From a10e8e47a5946623a60a1e36b9023c23926eae87 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Thu, 14 May 2026 13:31:31 -0400
Subject: [PATCH 001/222] fix: keep dependencies of `$state.eager`/`pending`
 (alternative approach) (#18218)

#18108, with two differences:

- we use a global map
- we use the parent reaction as the key, rather than traversing upwards
for a branch

I think this has the same outcome?

### Before submitting the PR, please make sure you do the following

- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).

### Tests and linting

- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/breezy-laws-train.md               |  5 +++
 .../src/internal/client/reactivity/batch.js   | 22 +++++++++++--
 .../samples/async-eager-block/_config.js      | 23 +++++++++++++
 .../samples/async-eager-block/main.svelte     | 20 ++++++++++++
 .../samples/async-eager-each-block/_config.js | 32 +++++++++++++++++++
 .../async-eager-each-block/main.svelte        | 24 ++++++++++++++
 6 files changed, 123 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/breezy-laws-train.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-eager-block/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-eager-block/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-eager-each-block/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-eager-each-block/main.svelte

diff --git a/.changeset/breezy-laws-train.md b/.changeset/breezy-laws-train.md
new file mode 100644
index 0000000000..5e88998a0a
--- /dev/null
+++ b/.changeset/breezy-laws-train.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: keep dependencies of `$state.eager/pending`
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index d822834324..a5c9a51eec 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -16,7 +16,8 @@ import {
 	EAGER_EFFECT,
 	ERROR_VALUE,
 	MANAGED_EFFECT,
-	REACTION_RAN
+	REACTION_RAN,
+	DESTROYING
 } from '#client/constants';
 import { async_mode_flag } from '../../flags/index.js';
 import { deferred, define_property, includes } from '../../shared/utils.js';
@@ -33,7 +34,7 @@ import { flush_tasks, queue_micro_task } from '../dom/task.js';
 import { DEV } from 'esm-env';
 import { invoke_error_boundary } from '../error-handling.js';
 import { flush_eager_effects, old_values, set_eager_effects, source, update } from './sources.js';
-import { eager_effect, unlink_effect } from './effects.js';
+import { eager_effect, teardown, unlink_effect } from './effects.js';
 import { defer_effect } from './utils.js';
 import { UNINITIALIZED } from '../../../constants.js';
 import { set_signal_status } from './status.js';
@@ -1234,6 +1235,9 @@ function eager_flush() {
 	});
 }
 
+/** @type {Map<Reaction, Source<number>>} */
+var version_map = new Map();
+
 /**
  * Implementation of `$state.eager(fn())`
  * @template T
@@ -1241,10 +1245,22 @@ function eager_flush() {
  * @returns {T}
  */
 export function eager(fn) {
-	var version = source(0);
 	var initial = true;
 	var value = /** @type {T} */ (undefined);
 
+	if (active_reaction === null) {
+		return fn();
+	}
+
+	let parent = active_reaction;
+
+	let version = version_map.get(parent) ?? source(0);
+	version_map.set(parent, version);
+
+	teardown(() => {
+		if (parent.f & DESTROYING) version_map.delete(parent);
+	});
+
 	get(version);
 
 	eager_effect(() => {
diff --git a/packages/svelte/tests/runtime-runes/samples/async-eager-block/_config.js b/packages/svelte/tests/runtime-runes/samples/async-eager-block/_config.js
new file mode 100644
index 0000000000..b6d283c8a5
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-eager-block/_config.js
@@ -0,0 +1,23 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		await tick();
+		const [increment, resolve] = target.querySelectorAll('button');
+
+		increment.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			'<button>increment</button> <button>resolve</button> 0 <p>loading...</p>'
+		);
+
+		resolve.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			'<button>increment</button> <button>resolve</button> 1 <p>1</p>'
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-eager-block/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-eager-block/main.svelte
new file mode 100644
index 0000000000..61f4705d06
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-eager-block/main.svelte
@@ -0,0 +1,20 @@
+<script>
+	let count = $state(0);
+
+	const queued = [];
+
+	async function delay(v) {
+		if (!v) return v;
+		return new Promise(r => queued.push(() => r(v)));
+	}
+</script>
+
+<button onclick={() => count++}>increment</button>
+<button onclick={() => queued.shift()?.()}>resolve</button>
+
+{await delay(count)} 
+{#if $state.eager(count) !== count}
+	<p>loading...</p>
+{:else}
+	<p>{count}</p>
+{/if}
diff --git a/packages/svelte/tests/runtime-runes/samples/async-eager-each-block/_config.js b/packages/svelte/tests/runtime-runes/samples/async-eager-each-block/_config.js
new file mode 100644
index 0000000000..a4921a5115
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-eager-each-block/_config.js
@@ -0,0 +1,32 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target, logs }) {
+		await tick();
+		const [increment, resolve] = target.querySelectorAll('button');
+		logs.length = 0;
+
+		increment.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`<button>increment</button> <button>resolve</button>
+			<ul><li>0 / 0</li><li>0 / loading...</li><li>0 / 0</li></ul>`
+		);
+
+		resolve.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`<button>increment</button> <button>resolve</button>
+			<ul><li>0 / 0</li><li>1 / 1</li><li>0 / 0</li></ul>`
+		);
+
+		assert.equal(
+			logs.some((l) => l.toString().includes('0 ') || l.toString().includes('2')),
+			false,
+			'only the second $state.eager should have been evaluated'
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-eager-each-block/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-eager-each-block/main.svelte
new file mode 100644
index 0000000000..f27e256e9f
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-eager-each-block/main.svelte
@@ -0,0 +1,24 @@
+<script>
+	let counts = $state([0, 0, 0]);
+	const queued = [];
+	async function delay(v) {
+		if (!v) return v;
+		return new Promise(r => queued.push(() => r(v)));
+	}
+</script>
+
+<button onclick={() => counts[1]++}>increment</button>
+<button onclick={() => queued.shift()?.()}>resolve</button>
+
+<ul>
+	{#each counts as count, i}
+		<li>
+			{await delay(count)} /
+			{#if console.log(i) || $state.eager(count) !== count}
+				loading...
+			{:else}
+				{count}
+			{/if}
+		</li>
+	{/each}
+</ul>

From 55f9c85c09d625c3dd80c71ce7542f57386fafb4 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Thu, 14 May 2026 14:03:20 -0400
Subject: [PATCH 002/222] Version Packages (#18158)

This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.


# Releases
## svelte@5.55.6

### Patch Changes

- fix: leave stale promises to wait for a later resolution, instead of
rejecting ([#18180](https://github.com/sveltejs/svelte/pull/18180))

- fix: keep dependencies of `$state.eager/pending`
([#18218](https://github.com/sveltejs/svelte/pull/18218))

- fix: reapply context after transforming error during SSR
([#18099](https://github.com/sveltejs/svelte/pull/18099))

- fix: don't rebase just-created batches
([#18117](https://github.com/sveltejs/svelte/pull/18117))

- chore: allow `null` for `pending` in typings
([#18201](https://github.com/sveltejs/svelte/pull/18201))

- fix: flush eager effects in production
([#18107](https://github.com/sveltejs/svelte/pull/18107))

- fix: rethrow error of failed iterable after calling `return()`
([#18169](https://github.com/sveltejs/svelte/pull/18169))

- fix: account for proxified instance when updating `bind:this`
([#18147](https://github.com/sveltejs/svelte/pull/18147))

- fix: ensure scheduled batch is flushed if not obsolete
([#18131](https://github.com/sveltejs/svelte/pull/18131))

- fix: resolve stale deriveds with latest value
([#18167](https://github.com/sveltejs/svelte/pull/18167))

- chore: remove unnecessary `increment_pending` calls
([#18183](https://github.com/sveltejs/svelte/pull/18183))

- fix: correctly compile component member expressions for SSR
([#18192](https://github.com/sveltejs/svelte/pull/18192))

- fix: reset `source.updated` stack traces after `flush`
([#18196](https://github.com/sveltejs/svelte/pull/18196))

- fix: replacing async 'blocking' strategy with 'merging'
([#18205](https://github.com/sveltejs/svelte/pull/18205))

- fix: allow `@debug` tags to reference awaited variables
([#18138](https://github.com/sveltejs/svelte/pull/18138))

- fix: re-run fallback props if dependencies update
([#18146](https://github.com/sveltejs/svelte/pull/18146))

- fix: abort running obsolete async branches
([#18118](https://github.com/sveltejs/svelte/pull/18118))

- fix: ignore comments when reading CSS values
([#18153](https://github.com/sveltejs/svelte/pull/18153))

- fix: wrap `Promise.all` in `save` during SSR
([#18178](https://github.com/sveltejs/svelte/pull/18178))

- fix: ignore false-positive errors of `$inspect` dependencies
([#18106](https://github.com/sveltejs/svelte/pull/18106))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/big-webs-sing.md        |  5 ----
 .changeset/breezy-laws-train.md    |  5 ----
 .changeset/cruel-boxes-serve.md    |  5 ----
 .changeset/easy-singers-retire.md  |  5 ----
 .changeset/fine-bushes-marry.md    |  5 ----
 .changeset/flat-shrimps-worry.md   |  5 ----
 .changeset/fresh-stars-grin.md     |  5 ----
 .changeset/full-waves-tease.md     |  5 ----
 .changeset/many-pandas-add.md      |  5 ----
 .changeset/modern-tables-fetch.md  |  5 ----
 .changeset/public-mammals-float.md |  5 ----
 .changeset/quiet-teams-pick.md     |  5 ----
 .changeset/red-crabs-ring.md       |  5 ----
 .changeset/shiny-squids-whisper.md |  5 ----
 .changeset/small-tools-walk.md     |  5 ----
 .changeset/smooth-poems-tap.md     |  5 ----
 .changeset/stupid-baboons-fall.md  |  5 ----
 .changeset/three-pears-build.md    |  5 ----
 .changeset/tough-knives-smell.md   |  5 ----
 .changeset/twelve-cooks-speak.md   |  5 ----
 packages/svelte/CHANGELOG.md       | 44 ++++++++++++++++++++++++++++++
 packages/svelte/package.json       |  2 +-
 packages/svelte/src/version.js     |  2 +-
 23 files changed, 46 insertions(+), 102 deletions(-)
 delete mode 100644 .changeset/big-webs-sing.md
 delete mode 100644 .changeset/breezy-laws-train.md
 delete mode 100644 .changeset/cruel-boxes-serve.md
 delete mode 100644 .changeset/easy-singers-retire.md
 delete mode 100644 .changeset/fine-bushes-marry.md
 delete mode 100644 .changeset/flat-shrimps-worry.md
 delete mode 100644 .changeset/fresh-stars-grin.md
 delete mode 100644 .changeset/full-waves-tease.md
 delete mode 100644 .changeset/many-pandas-add.md
 delete mode 100644 .changeset/modern-tables-fetch.md
 delete mode 100644 .changeset/public-mammals-float.md
 delete mode 100644 .changeset/quiet-teams-pick.md
 delete mode 100644 .changeset/red-crabs-ring.md
 delete mode 100644 .changeset/shiny-squids-whisper.md
 delete mode 100644 .changeset/small-tools-walk.md
 delete mode 100644 .changeset/smooth-poems-tap.md
 delete mode 100644 .changeset/stupid-baboons-fall.md
 delete mode 100644 .changeset/three-pears-build.md
 delete mode 100644 .changeset/tough-knives-smell.md
 delete mode 100644 .changeset/twelve-cooks-speak.md

diff --git a/.changeset/big-webs-sing.md b/.changeset/big-webs-sing.md
deleted file mode 100644
index 946a41d881..0000000000
--- a/.changeset/big-webs-sing.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: leave stale promises to wait for a later resolution, instead of rejecting
diff --git a/.changeset/breezy-laws-train.md b/.changeset/breezy-laws-train.md
deleted file mode 100644
index 5e88998a0a..0000000000
--- a/.changeset/breezy-laws-train.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: keep dependencies of `$state.eager/pending`
diff --git a/.changeset/cruel-boxes-serve.md b/.changeset/cruel-boxes-serve.md
deleted file mode 100644
index 592cec4d01..0000000000
--- a/.changeset/cruel-boxes-serve.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: reapply context after transforming error during SSR
diff --git a/.changeset/easy-singers-retire.md b/.changeset/easy-singers-retire.md
deleted file mode 100644
index 4420286e13..0000000000
--- a/.changeset/easy-singers-retire.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: don't rebase just-created batches
diff --git a/.changeset/fine-bushes-marry.md b/.changeset/fine-bushes-marry.md
deleted file mode 100644
index ccba53babe..0000000000
--- a/.changeset/fine-bushes-marry.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-chore: allow `null` for `pending` in typings
diff --git a/.changeset/flat-shrimps-worry.md b/.changeset/flat-shrimps-worry.md
deleted file mode 100644
index a5f76a0f9d..0000000000
--- a/.changeset/flat-shrimps-worry.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: flush eager effects in production
diff --git a/.changeset/fresh-stars-grin.md b/.changeset/fresh-stars-grin.md
deleted file mode 100644
index 3d56792d1e..0000000000
--- a/.changeset/fresh-stars-grin.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: rethrow error of failed iterable after calling `return()`
diff --git a/.changeset/full-waves-tease.md b/.changeset/full-waves-tease.md
deleted file mode 100644
index 3915334bf7..0000000000
--- a/.changeset/full-waves-tease.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: account for proxified instance when updating `bind:this`
diff --git a/.changeset/many-pandas-add.md b/.changeset/many-pandas-add.md
deleted file mode 100644
index 85de7acb35..0000000000
--- a/.changeset/many-pandas-add.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: ensure scheduled batch is flushed if not obsolete
diff --git a/.changeset/modern-tables-fetch.md b/.changeset/modern-tables-fetch.md
deleted file mode 100644
index 89543910fa..0000000000
--- a/.changeset/modern-tables-fetch.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: resolve stale deriveds with latest value
diff --git a/.changeset/public-mammals-float.md b/.changeset/public-mammals-float.md
deleted file mode 100644
index d890c9e070..0000000000
--- a/.changeset/public-mammals-float.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-chore: remove unnecessary `increment_pending` calls
diff --git a/.changeset/quiet-teams-pick.md b/.changeset/quiet-teams-pick.md
deleted file mode 100644
index ed046168be..0000000000
--- a/.changeset/quiet-teams-pick.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: correctly compile component member expressions for SSR
diff --git a/.changeset/red-crabs-ring.md b/.changeset/red-crabs-ring.md
deleted file mode 100644
index 82b53c5464..0000000000
--- a/.changeset/red-crabs-ring.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: reset `source.updated` stack traces after `flush`
diff --git a/.changeset/shiny-squids-whisper.md b/.changeset/shiny-squids-whisper.md
deleted file mode 100644
index a8d2d7378c..0000000000
--- a/.changeset/shiny-squids-whisper.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-"svelte": patch
----
-
-fix: replacing async 'blocking' strategy with 'merging'
diff --git a/.changeset/small-tools-walk.md b/.changeset/small-tools-walk.md
deleted file mode 100644
index 2b275368b3..0000000000
--- a/.changeset/small-tools-walk.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: allow `@debug` tags to reference awaited variables
diff --git a/.changeset/smooth-poems-tap.md b/.changeset/smooth-poems-tap.md
deleted file mode 100644
index ac160656cf..0000000000
--- a/.changeset/smooth-poems-tap.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: re-run fallback props if dependencies update
diff --git a/.changeset/stupid-baboons-fall.md b/.changeset/stupid-baboons-fall.md
deleted file mode 100644
index 66895ad015..0000000000
--- a/.changeset/stupid-baboons-fall.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: abort running obsolete async branches
diff --git a/.changeset/three-pears-build.md b/.changeset/three-pears-build.md
deleted file mode 100644
index 8a638149a3..0000000000
--- a/.changeset/three-pears-build.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: ignore comments when reading CSS values
diff --git a/.changeset/tough-knives-smell.md b/.changeset/tough-knives-smell.md
deleted file mode 100644
index 7687188c1a..0000000000
--- a/.changeset/tough-knives-smell.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: wrap `Promise.all` in `save` during SSR
diff --git a/.changeset/twelve-cooks-speak.md b/.changeset/twelve-cooks-speak.md
deleted file mode 100644
index d4fcd5c339..0000000000
--- a/.changeset/twelve-cooks-speak.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: ignore false-positive errors of `$inspect` dependencies
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 8e0f8a0916..e5ba5737c4 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,49 @@
 # svelte
 
+## 5.55.6
+
+### Patch Changes
+
+- fix: leave stale promises to wait for a later resolution, instead of rejecting ([#18180](https://github.com/sveltejs/svelte/pull/18180))
+
+- fix: keep dependencies of `$state.eager/pending` ([#18218](https://github.com/sveltejs/svelte/pull/18218))
+
+- fix: reapply context after transforming error during SSR ([#18099](https://github.com/sveltejs/svelte/pull/18099))
+
+- fix: don't rebase just-created batches ([#18117](https://github.com/sveltejs/svelte/pull/18117))
+
+- chore: allow `null` for `pending` in typings ([#18201](https://github.com/sveltejs/svelte/pull/18201))
+
+- fix: flush eager effects in production ([#18107](https://github.com/sveltejs/svelte/pull/18107))
+
+- fix: rethrow error of failed iterable after calling `return()` ([#18169](https://github.com/sveltejs/svelte/pull/18169))
+
+- fix: account for proxified instance when updating `bind:this` ([#18147](https://github.com/sveltejs/svelte/pull/18147))
+
+- fix: ensure scheduled batch is flushed if not obsolete ([#18131](https://github.com/sveltejs/svelte/pull/18131))
+
+- fix: resolve stale deriveds with latest value ([#18167](https://github.com/sveltejs/svelte/pull/18167))
+
+- chore: remove unnecessary `increment_pending` calls ([#18183](https://github.com/sveltejs/svelte/pull/18183))
+
+- fix: correctly compile component member expressions for SSR ([#18192](https://github.com/sveltejs/svelte/pull/18192))
+
+- fix: reset `source.updated` stack traces after `flush` ([#18196](https://github.com/sveltejs/svelte/pull/18196))
+
+- fix: replacing async 'blocking' strategy with 'merging' ([#18205](https://github.com/sveltejs/svelte/pull/18205))
+
+- fix: allow `@debug` tags to reference awaited variables ([#18138](https://github.com/sveltejs/svelte/pull/18138))
+
+- fix: re-run fallback props if dependencies update ([#18146](https://github.com/sveltejs/svelte/pull/18146))
+
+- fix: abort running obsolete async branches ([#18118](https://github.com/sveltejs/svelte/pull/18118))
+
+- fix: ignore comments when reading CSS values ([#18153](https://github.com/sveltejs/svelte/pull/18153))
+
+- fix: wrap `Promise.all` in `save` during SSR ([#18178](https://github.com/sveltejs/svelte/pull/18178))
+
+- fix: ignore false-positive errors of `$inspect` dependencies ([#18106](https://github.com/sveltejs/svelte/pull/18106))
+
 ## 5.55.5
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index a4ae208913..51aed56a3a 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.55.5",
+  "version": "5.55.6",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 04b0b0398a..b11e7635c7 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.55.5';
+export const VERSION = '5.55.6';
 export const PUBLIC_VERSION = '5';

From 547853e2406a2147ad7fb5ffeba95b01bd9642da Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Thu, 14 May 2026 20:51:28 +0200
Subject: [PATCH 003/222] Merge commit from fork

* fix: disallow empty attribute names during SSR

* Update packages/svelte/tests/server-side-rendering/samples/spread-attributes-event-handler-xss/main.svelte

Co-authored-by: Conduitry <git@chor.date>

---------

Co-authored-by: Elliott Johnson <hello@ell.iott.dev>
Co-authored-by: Conduitry <git@chor.date>
---
 .changeset/famous-webs-flash.md                            | 5 +++++
 packages/svelte/src/internal/server/index.js               | 2 +-
 .../spread-attributes-event-handler-xss/main.svelte        | 7 ++++++-
 3 files changed, 12 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/famous-webs-flash.md

diff --git a/.changeset/famous-webs-flash.md b/.changeset/famous-webs-flash.md
new file mode 100644
index 0000000000..75a01f689a
--- /dev/null
+++ b/.changeset/famous-webs-flash.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: disallow empty attribute names during SSR
diff --git a/packages/svelte/src/internal/server/index.js b/packages/svelte/src/internal/server/index.js
index 34d0133a31..12f76f188e 100644
--- a/packages/svelte/src/internal/server/index.js
+++ b/packages/svelte/src/internal/server/index.js
@@ -151,7 +151,7 @@ export function attributes(attrs, css_hash, classes, styles, flags = 0) {
 		// omit functions, internal svelte properties and invalid attribute names
 		if (typeof attrs[name] === 'function') continue;
 		if (name[0] === '$' && name[1] === '$') continue; // faster than name.startsWith('$$')
-		if (INVALID_ATTR_NAME_CHAR_REGEX.test(name)) continue;
+		if (name === '' || INVALID_ATTR_NAME_CHAR_REGEX.test(name)) continue;
 
 		var value = attrs[name];
 		var lower = name.toLowerCase();
diff --git a/packages/svelte/tests/server-side-rendering/samples/spread-attributes-event-handler-xss/main.svelte b/packages/svelte/tests/server-side-rendering/samples/spread-attributes-event-handler-xss/main.svelte
index 2a8c17f048..e47a19408e 100644
--- a/packages/svelte/tests/server-side-rendering/samples/spread-attributes-event-handler-xss/main.svelte
+++ b/packages/svelte/tests/server-side-rendering/samples/spread-attributes-event-handler-xss/main.svelte
@@ -5,7 +5,12 @@
 		onclick: 'alert(1)',
 		onerror: 'alert(1)',
 		onfocus: 'alert(1)',
-		onmouseover: 'alert(1)'
+		onmouseover: 'alert(1)',
+		' onload': 'alert(1)',
+		'\tonload': 'alert(1)',
+		'\u00a0onload': 'alert(1)',
+		"\t": "/onmouseover=alert(1)//",
+		"": "/onmouseover=alert(1)//"
 	};
 </script>
 

From d2375e2ebcab5c88feb5652f1a9d621b8f06b259 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Thu, 14 May 2026 20:51:56 +0200
Subject: [PATCH 004/222] Merge commit from fork

---
 .changeset/proud-dogs-go.md       |  5 ++++
 packages/svelte/src/utils.js      |  2 +-
 packages/svelte/src/utils.test.ts | 50 +++++++++++++++++++++++++++++++
 3 files changed, 56 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/proud-dogs-go.md
 create mode 100644 packages/svelte/src/utils.test.ts

diff --git a/.changeset/proud-dogs-go.md b/.changeset/proud-dogs-go.md
new file mode 100644
index 0000000000..c728466138
--- /dev/null
+++ b/.changeset/proud-dogs-go.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: harden regex
diff --git a/packages/svelte/src/utils.js b/packages/svelte/src/utils.js
index 57561e6dc7..54757a6f13 100644
--- a/packages/svelte/src/utils.js
+++ b/packages/svelte/src/utils.js
@@ -491,7 +491,7 @@ export function is_raw_text_element(name) {
 // Rejects strings containing whitespace, quotes, angle brackets, slashes, equals,
 // or other characters that could break out of a tag-name token and enable markup injection.
 export const REGEX_VALID_TAG_NAME =
-	/^[a-zA-Z][a-zA-Z0-9]*(-[a-zA-Z0-9.\-_\u00B7\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u037D\u037F-\u1FFF\u200C-\u200D\u203F-\u2040\u2070-\u218F\u2C00-\u2FEF\u3001-\uD7FF\uF900-\uFDCF\uFDF0-\uFFFD\u{10000}-\u{EFFFF}]+)*$/u;
+	/^[a-zA-Z][a-zA-Z0-9]*(-[a-zA-Z0-9.\-_\u00B7\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u037D\u037F-\u1FFF\u200C-\u200D\u203F-\u2040\u2070-\u218F\u2C00-\u2FEF\u3001-\uD7FF\uF900-\uFDCF\uFDF0-\uFFFD\u{10000}-\u{EFFFF}]*)?$/u;
 
 /**
  * Prevent devtools trying to make `location` a clickable link by inserting a zero-width space
diff --git a/packages/svelte/src/utils.test.ts b/packages/svelte/src/utils.test.ts
new file mode 100644
index 0000000000..02175ae93f
--- /dev/null
+++ b/packages/svelte/src/utils.test.ts
@@ -0,0 +1,50 @@
+import { expect, test } from 'vitest';
+import { REGEX_VALID_TAG_NAME } from './utils';
+
+test('REGEX_VALID_TAG_NAME accepts common HTML tag names', () => {
+	const common_html_tag_names = ['div', 'span', 'button', 'input', 'svg', 'math', 'a'];
+
+	for (const tag_name of common_html_tag_names) {
+		expect(REGEX_VALID_TAG_NAME.test(tag_name)).toBe(true);
+	}
+});
+
+test('REGEX_VALID_TAG_NAME accepts basic custom element names', () => {
+	const valid_custom_tag_names = ['my-element', 'x-foo', 'todo-item', 'my-element2'];
+
+	for (const tag_name of valid_custom_tag_names) {
+		expect(REGEX_VALID_TAG_NAME.test(tag_name)).toBe(true);
+	}
+});
+
+test('REGEX_VALID_TAG_NAME accepts spec-allowed custom element characters', () => {
+	const valid_custom_tag_names = [
+		'x-foo.bar',
+		'x-foo_bar',
+		'x-foo\u00B7bar',
+		'x-foo\u00FCbar',
+		'x-foo\u{1F600}bar',
+		'x-'
+	];
+
+	for (const tag_name of valid_custom_tag_names) {
+		expect(REGEX_VALID_TAG_NAME.test(tag_name)).toBe(true);
+	}
+});
+
+test('REGEX_VALID_TAG_NAME rejects invalid tag names', () => {
+	const invalid_tag_names = ['', '1', 'x\u00FC', '-x-foo', '1foo', 'x-foo bar', 'x-foo/', 'x-foo>'];
+
+	for (const tag_name of invalid_tag_names) {
+		expect(REGEX_VALID_TAG_NAME.test(tag_name)).toBe(false);
+	}
+});
+
+test('REGEX_VALID_TAG_NAME no ReDoS', () => {
+	const before = performance.now();
+	REGEX_VALID_TAG_NAME.test('a-----------------------------------!');
+	const after = performance.now();
+	if (after - before > 10) {
+		throw new Error(`REGEX_VALID_TAG_NAME is vulnerable to ReDoS`);
+	}
+});

From a16ebc67bbcf8f708360195687e1b2719463e1a4 Mon Sep 17 00:00:00 2001
From: Elliott Johnson <hello@ell.iott.dev>
Date: Thu, 14 May 2026 12:52:15 -0600
Subject: [PATCH 005/222] Merge commit from fork

https://github.com/sveltejs/svelte/security/advisories/GHSA-f3cj-j4f6-wq85

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/blue-lions-call.md                 |  5 +++
 .../svelte/src/internal/server/hydratable.js  |  9 +++--
 .../src/internal/server/hydratable.test.ts    | 33 +++++++++++++++++++
 playgrounds/sandbox/ssr-dev.js                |  5 +--
 playgrounds/sandbox/ssr-prod.js               |  5 +--
 5 files changed, 51 insertions(+), 6 deletions(-)
 create mode 100644 .changeset/blue-lions-call.md
 create mode 100644 packages/svelte/src/internal/server/hydratable.test.ts

diff --git a/.changeset/blue-lions-call.md b/.changeset/blue-lions-call.md
new file mode 100644
index 0000000000..f9ddb88505
--- /dev/null
+++ b/.changeset/blue-lions-call.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: prevent XSS on `hydratable` from user contents
diff --git a/packages/svelte/src/internal/server/hydratable.js b/packages/svelte/src/internal/server/hydratable.js
index 81f59ab2fd..be75288604 100644
--- a/packages/svelte/src/internal/server/hydratable.js
+++ b/packages/svelte/src/internal/server/hydratable.js
@@ -3,7 +3,6 @@ import { async_mode_flag } from '../flags/index.js';
 import { get_render_context } from './render-context.js';
 import * as e from './errors.js';
 import * as devalue from 'devalue';
-import { get_stack } from '../shared/dev.js';
 import { DEV } from 'esm-env';
 import { get_user_code_location } from './dev.js';
 
@@ -65,7 +64,13 @@ function encode(key, value, unresolved) {
 			const placeholder = `"${uid++}"`;
 			const p = value
 				.then((v) => {
-					entry.serialized = entry.serialized.replace(placeholder, `r(${uneval(v)})`);
+					entry.serialized = entry.serialized.replace(
+						placeholder,
+						// use the function form here to prevent any string replacement characters from being interpreted
+						// in `v`, as it's potentially user-controlled and therefore potentially malicious.
+						// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace#specifying_a_string_as_the_replacement
+						() => `r(${uneval(v)})`
+					);
 				})
 				.catch((devalue_error) =>
 					e.hydratable_serialization_failed(
diff --git a/packages/svelte/src/internal/server/hydratable.test.ts b/packages/svelte/src/internal/server/hydratable.test.ts
new file mode 100644
index 0000000000..8dd54c8f1d
--- /dev/null
+++ b/packages/svelte/src/internal/server/hydratable.test.ts
@@ -0,0 +1,33 @@
+import { afterAll, beforeAll, expect, test } from 'vitest';
+import { Renderer } from './renderer.js';
+import type { Component } from 'svelte';
+import { disable_async_mode_flag, enable_async_mode_flag } from '../flags/index.js';
+import { hydratable } from './hydratable.js';
+
+beforeAll(() => {
+	enable_async_mode_flag();
+});
+
+afterAll(() => {
+	disable_async_mode_flag();
+});
+
+test('treats replacement tokens in hydratable promise values as literals', async () => {
+	const component = (renderer: Renderer) => {
+		hydratable('key', () => Promise.resolve(`$'`));
+		renderer.child(async () => {
+			await Promise.resolve();
+		});
+		renderer.push('ok');
+	};
+
+	const { head } = await Renderer.render(component as unknown as Component);
+	const script_match = head.match(/<script(?:\s[^>]*)?>([\s\S]*)<\/script>/);
+
+	expect(script_match, 'expected hydratable script in head output').toBeTruthy();
+
+	const script_content = script_match![1];
+	expect(script_content).toContain('const h = (window.__svelte ??= {}).h ??= new Map();');
+	expect(script_content).toContain('r("$\'")');
+	expect(script_content).toMatch(/\[\s*"key"\s*,\s*r\("\$'"\)\s*\]/);
+});
diff --git a/playgrounds/sandbox/ssr-dev.js b/playgrounds/sandbox/ssr-dev.js
index 8a0c063d47..b770848ad1 100644
--- a/playgrounds/sandbox/ssr-dev.js
+++ b/playgrounds/sandbox/ssr-dev.js
@@ -29,8 +29,9 @@ polka()
 		const { head, body } = await render(App);
 
 		const html = transformed_template
-			.replace(`<!--ssr-head-->`, head)
-			.replace(`<!--ssr-body-->`, body)
+			// use function form to prevent any string replacement characters from being interpreted
+			.replace(`<!--ssr-head-->`, () => head)
+			.replace(`<!--ssr-body-->`, () => body)
 			// check that Safari doesn't break hydration
 			.replaceAll('+636-555-3226', '<a href="tel:+636-555-3226">+636-555-3226</a>');
 
diff --git a/playgrounds/sandbox/ssr-prod.js b/playgrounds/sandbox/ssr-prod.js
index 0c760188d4..e3ece4d5be 100644
--- a/playgrounds/sandbox/ssr-prod.js
+++ b/playgrounds/sandbox/ssr-prod.js
@@ -9,8 +9,9 @@ const { head, body } = await render(App);
 
 const rendered = fs
 	.readFileSync(path.resolve('./dist/client/index.html'), 'utf-8')
-	.replace(`<!--ssr-body-->`, body)
-	.replace(`<!--ssr-head-->`, head);
+	// use function form to prevent any string replacement characters from being interpreted
+	.replace(`<!--ssr-body-->`, () => body)
+	.replace(`<!--ssr-head-->`, () => head);
 
 const types = {
 	'.js': 'application/javascript',

From e1cbbd96441e82c9eb8a23a2903c0d06d3cda991 Mon Sep 17 00:00:00 2001
From: Elliott Johnson <hello@ell.iott.dev>
Date: Thu, 14 May 2026 12:59:01 -0600
Subject: [PATCH 006/222] Merge commit from fork

* fix: move Svelte runtime properties to symbols

Prevents DOM clobbering

* shorten names

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/six-snails-sell.md                 |  5 ++++
 .../svelte/src/internal/client/constants.js   |  5 ++++
 .../client/dom/elements/attributes.js         | 23 +++++++++++++------
 .../client/dom/elements/bindings/shared.js    | 10 ++++----
 .../src/internal/client/dom/elements/class.js |  7 +++---
 .../src/internal/client/dom/elements/misc.js  |  4 ++--
 .../src/internal/client/dom/elements/style.js |  7 +++---
 .../src/internal/client/dom/operations.js     | 23 ++++++++++---------
 packages/svelte/src/internal/client/render.js |  9 ++++----
 .../_config.js                                | 23 +++++++++++++++++++
 .../main.svelte                               | 20 ++++++++++++++++
 11 files changed, 97 insertions(+), 39 deletions(-)
 create mode 100644 .changeset/six-snails-sell.md
 create mode 100644 packages/svelte/tests/runtime-browser/samples/dom-clobbering-cache-symbols-spread/_config.js
 create mode 100644 packages/svelte/tests/runtime-browser/samples/dom-clobbering-cache-symbols-spread/main.svelte

diff --git a/.changeset/six-snails-sell.md b/.changeset/six-snails-sell.md
new file mode 100644
index 0000000000..6c61546e86
--- /dev/null
+++ b/.changeset/six-snails-sell.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: move Svelte runtime properties to symbols
diff --git a/packages/svelte/src/internal/client/constants.js b/packages/svelte/src/internal/client/constants.js
index f92fba73be..043b50b4b2 100644
--- a/packages/svelte/src/internal/client/constants.js
+++ b/packages/svelte/src/internal/client/constants.js
@@ -63,6 +63,11 @@ export const STATE_SYMBOL = Symbol('$state');
 export const LEGACY_PROPS = Symbol('legacy props');
 export const LOADING_ATTR_SYMBOL = Symbol('');
 export const PROXY_PATH_SYMBOL = Symbol('proxy path');
+export const ATTRIBUTES_CACHE = Symbol('attributes');
+export const CLASS_CACHE = Symbol('class');
+export const STYLE_CACHE = Symbol('style');
+export const TEXT_CACHE = Symbol('text');
+export const FORM_RESET_HANDLER = Symbol('form reset');
 /** An anchor might change, via this symbol on the original anchor we can tell HMR about the updated anchor */
 export const HMR_ANCHOR = Symbol('hmr anchor');
 
diff --git a/packages/svelte/src/internal/client/dom/elements/attributes.js b/packages/svelte/src/internal/client/dom/elements/attributes.js
index 0cec01191a..a193a70dd5 100644
--- a/packages/svelte/src/internal/client/dom/elements/attributes.js
+++ b/packages/svelte/src/internal/client/dom/elements/attributes.js
@@ -5,7 +5,12 @@ import { get_descriptors, get_prototype_of } from '../../../shared/utils.js';
 import { create_event, delegate, delegated, event, event_symbol } from './events.js';
 import { add_form_reset_listener, autofocus } from './misc.js';
 import * as w from '../../warnings.js';
-import { IS_XHTML, LOADING_ATTR_SYMBOL } from '#client/constants';
+import {
+	ATTRIBUTES_CACHE,
+	FORM_RESET_HANDLER,
+	IS_XHTML,
+	LOADING_ATTR_SYMBOL
+} from '#client/constants';
 import { queue_micro_task } from '../task.js';
 import { is_capture_event, can_delegate_event, normalize_attribute } from '../../../../utils.js';
 import {
@@ -69,8 +74,7 @@ export function remove_input_defaults(input) {
 		}
 	};
 
-	// @ts-expect-error
-	input.__on_r = remove_defaults;
+	/** @type {any} */ (input)[FORM_RESET_HANDLER] = remove_defaults;
 	queue_micro_task(remove_defaults);
 	add_form_reset_listener();
 }
@@ -561,8 +565,7 @@ export function attribute_effect(
  */
 function get_attributes(element) {
 	return /** @type {Record<string | symbol, unknown>} **/ (
-		// @ts-expect-error
-		element.__attributes ??= {
+		/** @type {any} */ (element)[ATTRIBUTES_CACHE] ??= {
 			[IS_CUSTOM_ELEMENT]: element.nodeName.includes('-'),
 			[IS_HTML]: element.namespaceURI === NAMESPACE_HTML
 		}
@@ -583,13 +586,19 @@ function get_setters(element) {
 	var proto = element; // In the case of custom elements there might be setters on the instance
 	var element_proto = Element.prototype;
 
-	// Stop at Element, from there on there's only unnecessary setters we're not interested in
+	// Stop at Element, from there on there's only unnecessary (and dangerous, like innerHTML) setters we're not interested in
 	// Do not use constructor.name here as that's unreliable in some browser environments
 	while (element_proto !== proto) {
 		descriptors = get_descriptors(proto);
 
 		for (var key in descriptors) {
-			if (descriptors[key].set) {
+			if (
+				descriptors[key].set &&
+				// better safe than sorry, we don't want spread attributes to mess with HTML content
+				key !== 'innerHTML' &&
+				key !== 'textContent' &&
+				key !== 'innerText'
+			) {
 				setters.push(key);
 			}
 		}
diff --git a/packages/svelte/src/internal/client/dom/elements/bindings/shared.js b/packages/svelte/src/internal/client/dom/elements/bindings/shared.js
index aa083776a5..303890adec 100644
--- a/packages/svelte/src/internal/client/dom/elements/bindings/shared.js
+++ b/packages/svelte/src/internal/client/dom/elements/bindings/shared.js
@@ -5,6 +5,7 @@ import {
 	set_active_effect,
 	set_active_reaction
 } from '../../../runtime.js';
+import { FORM_RESET_HANDLER } from '../../../constants.js';
 import { add_form_reset_listener } from '../misc.js';
 
 /**
@@ -58,18 +59,15 @@ export function without_reactive_context(fn) {
  */
 export function listen_to_event_and_reset_event(element, event, handler, on_reset = handler) {
 	element.addEventListener(event, () => without_reactive_context(handler));
-	// @ts-expect-error
-	const prev = element.__on_r;
+	const prev = /** @type {any} */ (element)[FORM_RESET_HANDLER];
 	if (prev) {
 		// special case for checkbox that can have multiple binds (group & checked)
-		// @ts-expect-error
-		element.__on_r = () => {
+		/** @type {any} */ (element)[FORM_RESET_HANDLER] = () => {
 			prev();
 			on_reset(true);
 		};
 	} else {
-		// @ts-expect-error
-		element.__on_r = () => on_reset(true);
+		/** @type {any} */ (element)[FORM_RESET_HANDLER] = () => on_reset(true);
 	}
 
 	add_form_reset_listener();
diff --git a/packages/svelte/src/internal/client/dom/elements/class.js b/packages/svelte/src/internal/client/dom/elements/class.js
index 038ce33f3e..6478707095 100644
--- a/packages/svelte/src/internal/client/dom/elements/class.js
+++ b/packages/svelte/src/internal/client/dom/elements/class.js
@@ -1,4 +1,5 @@
 import { to_class } from '../../../shared/attributes.js';
+import { CLASS_CACHE } from '../../constants.js';
 import { hydrating } from '../hydration.js';
 
 /**
@@ -11,8 +12,7 @@ import { hydrating } from '../hydration.js';
  * @returns {Record<string, boolean> | undefined}
  */
 export function set_class(dom, is_html, value, hash, prev_classes, next_classes) {
-	// @ts-expect-error need to add __className to patched prototype
-	var prev = dom.__className;
+	var prev = /** @type {any} */ (dom)[CLASS_CACHE];
 
 	if (
 		hydrating ||
@@ -35,8 +35,7 @@ export function set_class(dom, is_html, value, hash, prev_classes, next_classes)
 			}
 		}
 
-		// @ts-expect-error need to add __className to patched prototype
-		dom.__className = value;
+		/** @type {any} */ (dom)[CLASS_CACHE] = value;
 	} else if (next_classes && prev_classes !== next_classes) {
 		for (var key in next_classes) {
 			var is_present = !!next_classes[key];
diff --git a/packages/svelte/src/internal/client/dom/elements/misc.js b/packages/svelte/src/internal/client/dom/elements/misc.js
index f350d1df8c..ad34ab9c1d 100644
--- a/packages/svelte/src/internal/client/dom/elements/misc.js
+++ b/packages/svelte/src/internal/client/dom/elements/misc.js
@@ -1,6 +1,7 @@
 import { hydrating } from '../hydration.js';
 import { clear_text_content, get_first_child } from '../operations.js';
 import { queue_micro_task } from '../task.js';
+import { FORM_RESET_HANDLER } from '../../constants.js';
 
 /**
  * @param {HTMLElement} dom
@@ -45,8 +46,7 @@ export function add_form_reset_listener() {
 				Promise.resolve().then(() => {
 					if (!evt.defaultPrevented) {
 						for (const e of /**@type {HTMLFormElement} */ (evt.target).elements) {
-							// @ts-expect-error
-							e.__on_r?.();
+							/** @type {any} */ (e)[FORM_RESET_HANDLER]?.();
 						}
 					}
 				});
diff --git a/packages/svelte/src/internal/client/dom/elements/style.js b/packages/svelte/src/internal/client/dom/elements/style.js
index 3e05eec30e..740c225f29 100644
--- a/packages/svelte/src/internal/client/dom/elements/style.js
+++ b/packages/svelte/src/internal/client/dom/elements/style.js
@@ -1,4 +1,5 @@
 import { to_style } from '../../../shared/attributes.js';
+import { STYLE_CACHE } from '../../constants.js';
 import { hydrating } from '../hydration.js';
 
 /**
@@ -28,8 +29,7 @@ function update_styles(dom, prev = {}, next, priority) {
  * @param {Record<string, any> | [Record<string, any>, Record<string, any>]} [next_styles]
  */
 export function set_style(dom, value, prev_styles, next_styles) {
-	// @ts-expect-error
-	var prev = dom.__style;
+	var prev = /** @type {any} */ (dom)[STYLE_CACHE];
 
 	if (hydrating || prev !== value) {
 		var next_style_attr = to_style(value, next_styles);
@@ -42,8 +42,7 @@ export function set_style(dom, value, prev_styles, next_styles) {
 			}
 		}
 
-		// @ts-expect-error
-		dom.__style = value;
+		/** @type {any} */ (dom)[STYLE_CACHE] = value;
 	} else if (next_styles) {
 		if (Array.isArray(next_styles)) {
 			update_styles(dom, prev_styles?.[0], next_styles[0]);
diff --git a/packages/svelte/src/internal/client/dom/operations.js b/packages/svelte/src/internal/client/dom/operations.js
index 4036aa2d61..f6d05162ca 100644
--- a/packages/svelte/src/internal/client/dom/operations.js
+++ b/packages/svelte/src/internal/client/dom/operations.js
@@ -5,7 +5,14 @@ import { init_array_prototype_warnings } from '../dev/equality.js';
 import { get_descriptor, is_extensible } from '../../shared/utils.js';
 import { active_effect } from '../runtime.js';
 import { async_mode_flag } from '../../flags/index.js';
-import { TEXT_NODE, REACTION_RAN } from '#client/constants';
+import {
+	ATTRIBUTES_CACHE,
+	CLASS_CACHE,
+	REACTION_RAN,
+	STYLE_CACHE,
+	TEXT_CACHE,
+	TEXT_NODE
+} from '#client/constants';
 import { eager_block_effects } from '../reactivity/batch.js';
 import { NAMESPACE_HTML } from '../../../constants.js';
 
@@ -48,21 +55,15 @@ export function init_operations() {
 
 	if (is_extensible(element_prototype)) {
 		// the following assignments improve perf of lookups on DOM nodes
-		// @ts-expect-error
-		element_prototype.__click = undefined;
-		// @ts-expect-error
-		element_prototype.__className = undefined;
-		// @ts-expect-error
-		element_prototype.__attributes = null;
-		// @ts-expect-error
-		element_prototype.__style = undefined;
+		/** @type {any} */ (element_prototype)[CLASS_CACHE] = undefined;
+		/** @type {any} */ (element_prototype)[ATTRIBUTES_CACHE] = null;
+		/** @type {any} */ (element_prototype)[STYLE_CACHE] = undefined;
 		// @ts-expect-error
 		element_prototype.__e = undefined;
 	}
 
 	if (is_extensible(text_prototype)) {
-		// @ts-expect-error
-		text_prototype.__t = undefined;
+		/** @type {any} */ (text_prototype)[TEXT_CACHE] = undefined;
 	}
 
 	if (DEV) {
diff --git a/packages/svelte/src/internal/client/render.js b/packages/svelte/src/internal/client/render.js
index cb152ed9c1..50832fb3ff 100644
--- a/packages/svelte/src/internal/client/render.js
+++ b/packages/svelte/src/internal/client/render.js
@@ -23,7 +23,7 @@ import * as w from './warnings.js';
 import * as e from './errors.js';
 import { assign_nodes } from './dom/template.js';
 import { is_passive_event } from '../../utils.js';
-import { COMMENT_NODE, STATE_SYMBOL } from './constants.js';
+import { COMMENT_NODE, STATE_SYMBOL, TEXT_CACHE } from './constants.js';
 import { boundary } from './dom/blocks/boundary.js';
 
 /**
@@ -46,10 +46,9 @@ export function set_should_intro(value) {
 export function set_text(text, value) {
 	// For objects, we apply string coercion (which might make things like $state array references in the template reactive) before diffing
 	var str = value == null ? '' : typeof value === 'object' ? `${value}` : value;
-	// @ts-expect-error
-	if (str !== (text.__t ??= text.nodeValue)) {
-		// @ts-expect-error
-		text.__t = str;
+	// prettier-ignore
+	if (str !== (/** @type {any} */ (text)[TEXT_CACHE] ??= text.nodeValue)) {
+		/** @type {any} */ (text)[TEXT_CACHE] = str;
 		text.nodeValue = `${str}`;
 	}
 }
diff --git a/packages/svelte/tests/runtime-browser/samples/dom-clobbering-cache-symbols-spread/_config.js b/packages/svelte/tests/runtime-browser/samples/dom-clobbering-cache-symbols-spread/_config.js
new file mode 100644
index 0000000000..62248851db
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/samples/dom-clobbering-cache-symbols-spread/_config.js
@@ -0,0 +1,23 @@
+import { assert_ok, test } from '../../assert';
+
+export default test({
+	async test({ assert, target, waitUntil, window }) {
+		const form = target.querySelector('form');
+		const button = target.querySelector('button');
+		const [i1, i2, i3] = target.querySelectorAll('input');
+		assert_ok(form);
+		assert_ok(button);
+
+		assert.equal(form.id, 'initial-form');
+		assert.equal(form.className, 'first');
+		assert.equal(window.getComputedStyle(form).backgroundColor, 'rgb(255, 0, 0)');
+
+		button.click();
+		await waitUntil(() => form.id === 'updated-form');
+
+		assert.equal(form.id, 'updated-form');
+		assert.equal(form.className, 'second');
+		assert.equal(i3.id, '', 'input clobbered form');
+		assert.equal(window.getComputedStyle(form).backgroundColor, 'rgb(0, 0, 255)');
+	}
+});
diff --git a/packages/svelte/tests/runtime-browser/samples/dom-clobbering-cache-symbols-spread/main.svelte b/packages/svelte/tests/runtime-browser/samples/dom-clobbering-cache-symbols-spread/main.svelte
new file mode 100644
index 0000000000..60e9b80e81
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/samples/dom-clobbering-cache-symbols-spread/main.svelte
@@ -0,0 +1,20 @@
+<script>
+	let form_attributes = $state({ id: 'initial-form' });
+	let class_name = $state('first');
+	let background_color = $state('rgb(255, 0, 0)');
+
+	function update() {
+		form_attributes = { id: 'updated-form' };
+		class_name = 'second';
+		background_color = 'rgb(0, 0, 255)';
+	}
+</script>
+
+<button onclick={update}>update</button>
+
+<form {...form_attributes} class={class_name} style:background-color={background_color}>
+	<!-- the once non-symbol-ified hidden properties we used -->
+	<input {...{ name: '__className' }} value="x" />
+	<input {...{ name: '__style' }} value="y" />
+	<input {...{ name: '__attributes' }} value="z" />
+</form>

From 05523088173e10af0753877af6936088de924833 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Thu, 14 May 2026 15:00:51 -0400
Subject: [PATCH 007/222] chore: bump devalue (#18219)

---
 .changeset/eight-things-join.md |  5 +++++
 packages/svelte/package.json    |  2 +-
 pnpm-lock.yaml                  | 10 +++++-----
 3 files changed, 11 insertions(+), 6 deletions(-)
 create mode 100644 .changeset/eight-things-join.md

diff --git a/.changeset/eight-things-join.md b/.changeset/eight-things-join.md
new file mode 100644
index 0000000000..678d63db33
--- /dev/null
+++ b/.changeset/eight-things-join.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+chore: bump devalue
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 51aed56a3a..7e9521bb57 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -176,7 +176,7 @@
     "aria-query": "5.3.1",
     "axobject-query": "^4.1.0",
     "clsx": "^2.1.1",
-    "devalue": "^5.6.4",
+    "devalue": "^5.8.1",
     "esm-env": "^1.2.1",
     "esrap": "^2.2.4",
     "is-reference": "^3.0.3",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 0e2be208b6..1bfee5c769 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -96,8 +96,8 @@ importers:
         specifier: ^2.1.1
         version: 2.1.1
       devalue:
-        specifier: ^5.6.4
-        version: 5.6.4
+        specifier: ^5.8.1
+        version: 5.8.1
       esm-env:
         specifier: ^1.2.1
         version: 1.2.1
@@ -1418,8 +1418,8 @@ packages:
     engines: {node: '>=0.10'}
     hasBin: true
 
-  devalue@5.6.4:
-    resolution: {integrity: sha512-Gp6rDldRsFh/7XuouDbxMH3Mx8GMCcgzIb1pDTvNyn8pZGQ22u+Wa+lGV9dQCltFQ7uVw0MhRyb8XDskNFOReA==}
+  devalue@5.8.1:
+    resolution: {integrity: sha512-4CXDYRBGqN+57wVJkuXBYmpAVUSg3L6JAQa/DFqm238G73E1wuyc/JhGQJzN7vUf/CMphYau2zXbfWzDR5aTEw==}
 
   dir-glob@3.0.1:
     resolution: {integrity: sha512-WkrWp9GR4KXfKGYzOLmTuGVi1UWFfws377n9cc55/tb6DuqyF6pcQ5AbiHEshaDpY9v6oaSr2XCDidGmMwdzIA==}
@@ -3786,7 +3786,7 @@ snapshots:
   detect-libc@1.0.3:
     optional: true
 
-  devalue@5.6.4: {}
+  devalue@5.8.1: {}
 
   dir-glob@3.0.1:
     dependencies:

From 4d8f99a2709e3c02e48d8bc6c77458f4ba49d0e3 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Thu, 14 May 2026 13:06:06 -0600
Subject: [PATCH 008/222] Version Packages (#18220)

This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.


# Releases
## svelte@5.55.7

### Patch Changes

- fix: prevent XSS on `hydratable` from user contents
([`a16ebc67bbcf8f708360195687e1b2719463e1a4`](https://github.com/sveltejs/svelte/commit/a16ebc67bbcf8f708360195687e1b2719463e1a4))

- chore: bump devalue
([#18219](https://github.com/sveltejs/svelte/pull/18219))

- fix: disallow empty attribute names during SSR
([`547853e2406a2147ad7fb5ffeba95b01bd9642da`](https://github.com/sveltejs/svelte/commit/547853e2406a2147ad7fb5ffeba95b01bd9642da))

- fix: harden regex
([`d2375e2ebcab5c88feb5652f1a9d621b8f06b259`](https://github.com/sveltejs/svelte/commit/d2375e2ebcab5c88feb5652f1a9d621b8f06b259))

- fix: move Svelte runtime properties to symbols
([`e1cbbd96441e82c9eb8a23a2903c0d06d3cda991`](https://github.com/sveltejs/svelte/commit/e1cbbd96441e82c9eb8a23a2903c0d06d3cda991))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/blue-lions-call.md   |  5 -----
 .changeset/eight-things-join.md |  5 -----
 .changeset/famous-webs-flash.md |  5 -----
 .changeset/proud-dogs-go.md     |  5 -----
 .changeset/six-snails-sell.md   |  5 -----
 packages/svelte/CHANGELOG.md    | 14 ++++++++++++++
 packages/svelte/package.json    |  2 +-
 packages/svelte/src/version.js  |  2 +-
 8 files changed, 16 insertions(+), 27 deletions(-)
 delete mode 100644 .changeset/blue-lions-call.md
 delete mode 100644 .changeset/eight-things-join.md
 delete mode 100644 .changeset/famous-webs-flash.md
 delete mode 100644 .changeset/proud-dogs-go.md
 delete mode 100644 .changeset/six-snails-sell.md

diff --git a/.changeset/blue-lions-call.md b/.changeset/blue-lions-call.md
deleted file mode 100644
index f9ddb88505..0000000000
--- a/.changeset/blue-lions-call.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: prevent XSS on `hydratable` from user contents
diff --git a/.changeset/eight-things-join.md b/.changeset/eight-things-join.md
deleted file mode 100644
index 678d63db33..0000000000
--- a/.changeset/eight-things-join.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-chore: bump devalue
diff --git a/.changeset/famous-webs-flash.md b/.changeset/famous-webs-flash.md
deleted file mode 100644
index 75a01f689a..0000000000
--- a/.changeset/famous-webs-flash.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: disallow empty attribute names during SSR
diff --git a/.changeset/proud-dogs-go.md b/.changeset/proud-dogs-go.md
deleted file mode 100644
index c728466138..0000000000
--- a/.changeset/proud-dogs-go.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: harden regex
diff --git a/.changeset/six-snails-sell.md b/.changeset/six-snails-sell.md
deleted file mode 100644
index 6c61546e86..0000000000
--- a/.changeset/six-snails-sell.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: move Svelte runtime properties to symbols
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index e5ba5737c4..1255d8c6a0 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,19 @@
 # svelte
 
+## 5.55.7
+
+### Patch Changes
+
+- fix: prevent XSS on `hydratable` from user contents ([`a16ebc67bbcf8f708360195687e1b2719463e1a4`](https://github.com/sveltejs/svelte/commit/a16ebc67bbcf8f708360195687e1b2719463e1a4))
+
+- chore: bump devalue ([#18219](https://github.com/sveltejs/svelte/pull/18219))
+
+- fix: disallow empty attribute names during SSR ([`547853e2406a2147ad7fb5ffeba95b01bd9642da`](https://github.com/sveltejs/svelte/commit/547853e2406a2147ad7fb5ffeba95b01bd9642da))
+
+- fix: harden regex ([`d2375e2ebcab5c88feb5652f1a9d621b8f06b259`](https://github.com/sveltejs/svelte/commit/d2375e2ebcab5c88feb5652f1a9d621b8f06b259))
+
+- fix: move Svelte runtime properties to symbols ([`e1cbbd96441e82c9eb8a23a2903c0d06d3cda991`](https://github.com/sveltejs/svelte/commit/e1cbbd96441e82c9eb8a23a2903c0d06d3cda991))
+
 ## 5.55.6
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 7e9521bb57..2f0743641f 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.55.6",
+  "version": "5.55.7",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index b11e7635c7..6b0ed0aea8 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.55.6';
+export const VERSION = '5.55.7';
 export const PUBLIC_VERSION = '5';

From eb10a70cf1f003c3e93f3c4ecc9749870e7581c6 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Mon, 18 May 2026 17:36:17 +0200
Subject: [PATCH 009/222] fix: unset context synchronously in `run` (#18236)

Our `run` function which executes top level awaits (and synchronous
statements in-between/after) did not unset the context in time in case
the function returns an async value. In that case the context was still
around until the that promise resolves, which can be too late because
unrelated things can be intertwined with the batch.

The test shows this: Without the fix, the unrelated count incrementation
would not update the view until the top level awaits in the child are
done. In the test this just shows as a delayed visual update, but it
also can result in stale roots as shown in
https://github.com/sveltejs/svelte/issues/18221#issuecomment-4470921077
---
 .changeset/tangy-icons-dig.md                 |  5 ++++
 .../src/internal/client/reactivity/async.js   | 23 ++++++++++------
 .../async-run-isolated-batch/Child.svelte     |  7 +++++
 .../async-run-isolated-batch/_config.js       | 26 +++++++++++++++++++
 .../async-run-isolated-batch/main.svelte      | 23 ++++++++++++++++
 5 files changed, 76 insertions(+), 8 deletions(-)
 create mode 100644 .changeset/tangy-icons-dig.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-run-isolated-batch/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-run-isolated-batch/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-run-isolated-batch/main.svelte

diff --git a/.changeset/tangy-icons-dig.md b/.changeset/tangy-icons-dig.md
new file mode 100644
index 0000000000..6d87912bbb
--- /dev/null
+++ b/.changeset/tangy-icons-dig.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: unset context synchronously in `run`
diff --git a/packages/svelte/src/internal/client/reactivity/async.js b/packages/svelte/src/internal/client/reactivity/async.js
index c1d4cbcd67..12c5e9baa5 100644
--- a/packages/svelte/src/internal/client/reactivity/async.js
+++ b/packages/svelte/src/internal/client/reactivity/async.js
@@ -303,15 +303,21 @@ export function run(thunks) {
 			.then(() => {
 				restore();
 
-				if (errored) {
-					throw errored.error;
+				try {
+					if (errored) {
+						throw errored.error;
+					}
+
+					if (aborted(active)) {
+						throw STALE_REACTION;
+					}
+
+					return fn();
+				} finally {
+					// We gotta unset context directly in case the function returns a promise, in which case
+					// unset_context in .finally() would be too late ...
+					unset_context();
 				}
-
-				if (aborted(active)) {
-					throw STALE_REACTION;
-				}
-
-				return fn();
 			})
 			.catch(handle_error);
 
@@ -320,6 +326,7 @@ export function run(thunks) {
 
 		promise.finally(() => {
 			blocker.settled = true;
+			// ... but we also need it after such a promise has resolved in case it restores our context
 			unset_context();
 		});
 	}
diff --git a/packages/svelte/tests/runtime-runes/samples/async-run-isolated-batch/Child.svelte b/packages/svelte/tests/runtime-runes/samples/async-run-isolated-batch/Child.svelte
new file mode 100644
index 0000000000..6f84dc319e
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-run-isolated-batch/Child.svelte
@@ -0,0 +1,7 @@
+<script>
+	import { push } from "./main.svelte";
+	const x = await push(1);
+	const y = await push(2);
+</script>
+
+{x} {y}
diff --git a/packages/svelte/tests/runtime-runes/samples/async-run-isolated-batch/_config.js b/packages/svelte/tests/runtime-runes/samples/async-run-isolated-batch/_config.js
new file mode 100644
index 0000000000..a0dc38c660
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-run-isolated-batch/_config.js
@@ -0,0 +1,26 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		const [show, resolve, count] = target.querySelectorAll('button');
+
+		show.click();
+		await tick();
+		resolve.click();
+		await tick();
+		count.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			'<button>show</button> <button>resolve</button> <button>1</button>'
+		);
+
+		resolve.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			'1 2 <button>show</button> <button>resolve</button> <button>1</button>'
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-run-isolated-batch/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-run-isolated-batch/main.svelte
new file mode 100644
index 0000000000..0a5346cc47
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-run-isolated-batch/main.svelte
@@ -0,0 +1,23 @@
+<script module>
+	const queued = [];
+	export function push(v) {
+		return new Promise((fulfil) => {
+			queued.push(() => fulfil(v));
+		});
+	}
+</script>
+
+<script>
+	import Child from "./Child.svelte";
+
+	let show = $state(false);
+	let count = $state(0);
+</script>
+
+{#if show}
+	<Child />
+{/if}
+
+<button onclick={() => show = true}>show</button>
+<button onclick={() => queued.shift()?.()}>resolve</button>
+<button onclick={() => count++}>{count}</button>

From 1e899cba354d2b25593afc1bbf04bf3555b5d26a Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Mon, 18 May 2026 17:36:41 +0200
Subject: [PATCH 010/222] fix: execute uninitialized derived even if it's
 destroyed (#18228)

Turns out there are a few unavoidable cases where we have to execute the
derived even if we otherwise wouldn't, because of its lazy nature.
Fixes #18139
---
 .changeset/hungry-ads-beam.md                 |  5 +++
 .../internal/client/reactivity/deriveds.js    |  7 +++-
 .../Child.svelte                              | 10 ++++++
 .../_config.js                                | 32 +++++++++++++++++++
 .../main.svelte                               | 11 +++++++
 5 files changed, 64 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/hungry-ads-beam.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/transition-derived-uninitialized/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/transition-derived-uninitialized/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/transition-derived-uninitialized/main.svelte

diff --git a/.changeset/hungry-ads-beam.md b/.changeset/hungry-ads-beam.md
new file mode 100644
index 0000000000..260d177119
--- /dev/null
+++ b/.changeset/hungry-ads-beam.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: execute uninitialized derived even if it's destroyed
diff --git a/packages/svelte/src/internal/client/reactivity/deriveds.js b/packages/svelte/src/internal/client/reactivity/deriveds.js
index 83e23dfab6..75be018552 100644
--- a/packages/svelte/src/internal/client/reactivity/deriveds.js
+++ b/packages/svelte/src/internal/client/reactivity/deriveds.js
@@ -338,7 +338,12 @@ export function execute_derived(derived) {
 	var prev_active_effect = active_effect;
 	var parent = derived.parent;
 
-	if (!is_destroying_effect && parent !== null && (parent.f & (DESTROYED | INERT)) !== 0) {
+	if (
+		!is_destroying_effect &&
+		parent !== null &&
+		derived.v !== UNINITIALIZED && // if it was never evaluated before, it's guaranteed to fail downstream, so we try to execute instead
+		(parent.f & (DESTROYED | INERT)) !== 0
+	) {
 		w.derived_inert();
 
 		return derived.v;
diff --git a/packages/svelte/tests/runtime-runes/samples/transition-derived-uninitialized/Child.svelte b/packages/svelte/tests/runtime-runes/samples/transition-derived-uninitialized/Child.svelte
new file mode 100644
index 0000000000..20bd606d9b
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/transition-derived-uninitialized/Child.svelte
@@ -0,0 +1,10 @@
+<script>
+	import { fly } from 'svelte/transition';
+
+	// Not read before the outro, by which time the derived is destroyed
+	let duration = $derived(10);
+</script>
+
+<div in:fly={{ duration: 10 }} out:fly={{ duration }}>
+	hello
+</div>
diff --git a/packages/svelte/tests/runtime-runes/samples/transition-derived-uninitialized/_config.js b/packages/svelte/tests/runtime-runes/samples/transition-derived-uninitialized/_config.js
new file mode 100644
index 0000000000..734c84a0c4
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/transition-derived-uninitialized/_config.js
@@ -0,0 +1,32 @@
+import { flushSync } from 'svelte';
+import { raf } from '../../../animation-helpers';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		const [fly_in, fly_out] = target.querySelectorAll('button');
+
+		fly_in.click();
+		flushSync();
+		raf.tick(25);
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>fly in</button>
+				<button>fly out</button>
+				<div style="">hello</div>
+			`
+		);
+
+		fly_out.click();
+		flushSync();
+		raf.tick(50);
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>fly in</button>
+				<button>fly out</button>
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/transition-derived-uninitialized/main.svelte b/packages/svelte/tests/runtime-runes/samples/transition-derived-uninitialized/main.svelte
new file mode 100644
index 0000000000..4fc3395af8
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/transition-derived-uninitialized/main.svelte
@@ -0,0 +1,11 @@
+<script>
+	import Child from './Child.svelte';
+	let show = $state(false);
+</script>
+
+<button onclick={() => (show = true)}>fly in</button>
+<button onclick={() => (show = false)}>fly out</button>
+
+{#if show}
+	<Child />
+{/if}

From dc1f037fa67bf2fbdeb1c5f18b2b1f7d023077e3 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Mon, 18 May 2026 17:37:01 +0200
Subject: [PATCH 011/222] fix: don't run teardown effects when deriveds are
 unfreezed (#18227)

The logic was flawed - a teardown effect only has a teardown function
but not `fn` property, but unfreeze thought that everything with a
`teardown` needs to be unfreezed

Helps with #18221 (though likely doesn't fix it completely, at least not
the more general `batch.#roots`problems)
---
 .changeset/slimy-olives-cross.md              |  5 +++++
 .../internal/client/reactivity/deriveds.js    |  6 +++---
 .../async-state-eager-const/_config.js        | 21 +++++++++++++++++++
 .../async-state-eager-const/main.svelte       | 21 +++++++++++++++++++
 4 files changed, 50 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/slimy-olives-cross.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-state-eager-const/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-state-eager-const/main.svelte

diff --git a/.changeset/slimy-olives-cross.md b/.changeset/slimy-olives-cross.md
new file mode 100644
index 0000000000..3309e2deab
--- /dev/null
+++ b/.changeset/slimy-olives-cross.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: don't run teardown effects when deriveds are unfreezed
diff --git a/packages/svelte/src/internal/client/reactivity/deriveds.js b/packages/svelte/src/internal/client/reactivity/deriveds.js
index 75be018552..8d240bca31 100644
--- a/packages/svelte/src/internal/client/reactivity/deriveds.js
+++ b/packages/svelte/src/internal/client/reactivity/deriveds.js
@@ -452,8 +452,8 @@ export function freeze_derived_effects(derived) {
 			// make it a noop so it doesn't get called again if the derived
 			// is unfrozen. we don't set it to `null`, because the existence
 			// of a teardown function is what determines whether the
-			// effect runs again during unfreezing
-			e.teardown = noop;
+			// effect runs again during unfreezing (but not for teardown-only effects)
+			if (e.fn !== null) e.teardown = noop;
 			e.ac = null;
 
 			remove_reactions(e, 0);
@@ -471,7 +471,7 @@ export function unfreeze_derived_effects(derived) {
 	for (const e of derived.effects) {
 		// if the effect was previously frozen — indicated by the presence
 		// of a teardown function — unfreeze it
-		if (e.teardown) {
+		if (e.teardown && e.fn !== null) {
 			update_effect(e);
 		}
 	}
diff --git a/packages/svelte/tests/runtime-runes/samples/async-state-eager-const/_config.js b/packages/svelte/tests/runtime-runes/samples/async-state-eager-const/_config.js
new file mode 100644
index 0000000000..1511d443e5
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-state-eager-const/_config.js
@@ -0,0 +1,21 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	compileOptions: { dev: true }, // for testing that teardown effect in eager $.get(loaded) doesn't lead to a crash (because it means REACTION_RAN is set, which means unfreeze_derived runs)
+	async test({ assert, target }) {
+		const [count, shift] = target.querySelectorAll('button');
+
+		shift.click();
+		await tick();
+		assert.htmlEqual(target.innerHTML, `<button>0</button><button>shift</button><p>0</p>`);
+
+		count.click();
+		await tick();
+		assert.htmlEqual(target.innerHTML, `<button>1</button><button>shift</button><p>0 (...)</p>`);
+
+		shift.click();
+		await tick();
+		assert.htmlEqual(target.innerHTML, `<button>1</button><button>shift</button><p>1</p>`);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-state-eager-const/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-state-eager-const/main.svelte
new file mode 100644
index 0000000000..f0e2f1cdac
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-state-eager-const/main.svelte
@@ -0,0 +1,21 @@
+<script>
+	let count = $state(0);
+
+	let resolvers = [];
+
+	function push(value) {
+		const { promise, resolve } = Promise.withResolvers();
+		resolvers.push(() => resolve(value));
+		return promise;
+	}
+</script>
+
+<button onclick={() => count += 1}>{$state.eager(count)}</button>
+<button onclick={() => resolvers.shift()?.()}>shift</button>
+
+<svelte:boundary>
+	{@const loaded = $state.eager(count) === count}
+	<p>{await push(count)} {loaded ? '' : '(...)'}</p>
+
+	{#snippet pending()}{/snippet}
+</svelte:boundary>

From 2bc3592eb1ba1b37bde6c893e84b28e2f630db59 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Mon, 18 May 2026 11:53:31 -0400
Subject: [PATCH 012/222] fix: use named symbols everywhere (#18238)

This isn't _really_ a fix since these should never surface to the user,
but it's useful for debugging when they do, as in
https://github.com/sveltejs/kit/pull/15779. Instead of seeing `Symbol()`
we see e.g. `Symbol(uninitialized)` which makes it easier to understand
where a bug is coming from.
---
 .changeset/red-moles-talk.md                            | 5 +++++
 packages/svelte/src/constants.js                        | 2 +-
 packages/svelte/src/internal/client/reactivity/store.js | 2 +-
 packages/svelte/src/reactivity/url-search-params.js     | 2 +-
 4 files changed, 8 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/red-moles-talk.md

diff --git a/.changeset/red-moles-talk.md b/.changeset/red-moles-talk.md
new file mode 100644
index 0000000000..7e09dc9b9a
--- /dev/null
+++ b/.changeset/red-moles-talk.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: use named symbols everywhere
diff --git a/packages/svelte/src/constants.js b/packages/svelte/src/constants.js
index a3a109b943..1e721b7d30 100644
--- a/packages/svelte/src/constants.js
+++ b/packages/svelte/src/constants.js
@@ -32,7 +32,7 @@ export const ELEMENT_IS_NAMESPACED = 1;
 export const ELEMENT_PRESERVE_ATTRIBUTE_CASE = 1 << 1;
 export const ELEMENT_IS_INPUT = 1 << 2;
 
-export const UNINITIALIZED = Symbol();
+export const UNINITIALIZED = Symbol('uninitialized');
 
 // Dev-time component properties
 export const FILENAME = Symbol('filename');
diff --git a/packages/svelte/src/internal/client/reactivity/store.js b/packages/svelte/src/internal/client/reactivity/store.js
index 7124e23db8..726765b619 100644
--- a/packages/svelte/src/internal/client/reactivity/store.js
+++ b/packages/svelte/src/internal/client/reactivity/store.js
@@ -21,7 +21,7 @@ export let legacy_is_updating_store = false;
  */
 let is_store_binding = false;
 
-let IS_UNMOUNTED = Symbol();
+let IS_UNMOUNTED = Symbol('unmounted');
 
 /**
  * Gets the current value of a store. If the store isn't subscribed to yet, it will create a proxy
diff --git a/packages/svelte/src/reactivity/url-search-params.js b/packages/svelte/src/reactivity/url-search-params.js
index 2381e11875..2e70bf518d 100644
--- a/packages/svelte/src/reactivity/url-search-params.js
+++ b/packages/svelte/src/reactivity/url-search-params.js
@@ -4,7 +4,7 @@ import { tag } from '../internal/client/dev/tracing.js';
 import { get } from '../internal/client/runtime.js';
 import { get_current_url } from './url.js';
 
-export const REPLACE = Symbol();
+export const REPLACE = Symbol('replace');
 
 /**
  * A reactive version of the built-in [`URLSearchParams`](https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams) object.

From ca3f35bf7d3eeea6d0b5f477d208c3fd9c19988c Mon Sep 17 00:00:00 2001
From: OfirHaf <ofir135001@gmail.com>
Date: Mon, 18 May 2026 18:54:31 +0300
Subject: [PATCH 013/222] fix(print): handle svelte:body and fix keyframe
 percentage double-printing (#18234)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Fixes #18206 and fixes #18207 — both are printer bugs in
`packages/svelte/src/compiler/print/index.js`.

## Changes

### Fix 1: `svelte:body` crashes the printer (#18206)

`SvelteBody` was missing from the visitor map, causing a crash with
`Error: Not implemented: SvelteBody`. Added the handler (same one-liner
pattern as `SvelteDocument`, `SvelteHead`, etc.) and added `SvelteBody`
to the `is_block_element` check so whitespace is handled consistently.

### Fix 2: Keyframe percent stops print as `0%%` (#18207)

`Percentage.value` already includes the `%` sign (captured by
`/\d+(\.\d+)?%/y`), but the printer was writing `` `${node.value}%` `` —
appending a second `%`. Changed to `context.write(node.value)` to match
the `Nth` printer pattern directly above it.

Also updated the existing `style` snapshot which had `50%%` (the bug was
silently baked in), and added dedicated test samples for both fixes.
---
 .../fix-printer-svelte-body-keyframe-percent.md     |  5 +++++
 packages/svelte/src/compiler/print/index.js         |  7 ++++++-
 .../samples/css-keyframes-percent/input.svelte      |  7 +++++++
 .../samples/css-keyframes-percent/output.svelte     | 13 +++++++++++++
 .../svelte/tests/print/samples/style/output.svelte  |  2 +-
 .../tests/print/samples/svelte-body/input.svelte    |  1 +
 .../tests/print/samples/svelte-body/output.svelte   |  1 +
 7 files changed, 34 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/fix-printer-svelte-body-keyframe-percent.md
 create mode 100644 packages/svelte/tests/print/samples/css-keyframes-percent/input.svelte
 create mode 100644 packages/svelte/tests/print/samples/css-keyframes-percent/output.svelte
 create mode 100644 packages/svelte/tests/print/samples/svelte-body/input.svelte
 create mode 100644 packages/svelte/tests/print/samples/svelte-body/output.svelte

diff --git a/.changeset/fix-printer-svelte-body-keyframe-percent.md b/.changeset/fix-printer-svelte-body-keyframe-percent.md
new file mode 100644
index 0000000000..6854468835
--- /dev/null
+++ b/.changeset/fix-printer-svelte-body-keyframe-percent.md
@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+fix(print): handle `svelte:body` and fix keyframe percentage double-printing
diff --git a/packages/svelte/src/compiler/print/index.js b/packages/svelte/src/compiler/print/index.js
index 26dc1b88e8..c511ee6da0 100644
--- a/packages/svelte/src/compiler/print/index.js
+++ b/packages/svelte/src/compiler/print/index.js
@@ -247,7 +247,7 @@ const css_visitors = {
 	},
 
 	Percentage(node, context) {
-		context.write(`${node.value}%`);
+		context.write(node.value);
 	},
 
 	PseudoClassSelector(node, context) {
@@ -417,6 +417,7 @@ const svelte_visitors = (comments) => ({
 				const is_block_element =
 					child_node.type === 'RegularElement' ||
 					child_node.type === 'Component' ||
+					child_node.type === 'SvelteBody' ||
 					child_node.type === 'SvelteHead' ||
 					child_node.type === 'SvelteFragment' ||
 					child_node.type === 'SvelteBoundary' ||
@@ -821,6 +822,10 @@ const svelte_visitors = (comments) => ({
 		context.write('</style>');
 	},
 
+	SvelteBody(node, context) {
+		base_element(node, context, comments);
+	},
+
 	SvelteBoundary(node, context) {
 		base_element(node, context, comments);
 	},
diff --git a/packages/svelte/tests/print/samples/css-keyframes-percent/input.svelte b/packages/svelte/tests/print/samples/css-keyframes-percent/input.svelte
new file mode 100644
index 0000000000..b2a0e3aa7a
--- /dev/null
+++ b/packages/svelte/tests/print/samples/css-keyframes-percent/input.svelte
@@ -0,0 +1,7 @@
+<style>
+  @keyframes foo {
+    0% { left: 0px; }
+    50% { left: 50px; }
+    100% { left: 100px; }
+  }
+</style>
diff --git a/packages/svelte/tests/print/samples/css-keyframes-percent/output.svelte b/packages/svelte/tests/print/samples/css-keyframes-percent/output.svelte
new file mode 100644
index 0000000000..e35a5780fa
--- /dev/null
+++ b/packages/svelte/tests/print/samples/css-keyframes-percent/output.svelte
@@ -0,0 +1,13 @@
+<style>
+	@keyframes foo {
+		0% {
+			left: 0px;
+		}
+		50% {
+			left: 50px;
+		}
+		100% {
+			left: 100px;
+		}
+	}
+</style>
diff --git a/packages/svelte/tests/print/samples/style/output.svelte b/packages/svelte/tests/print/samples/style/output.svelte
index 03168cccae..9fc5e3fbba 100644
--- a/packages/svelte/tests/print/samples/style/output.svelte
+++ b/packages/svelte/tests/print/samples/style/output.svelte
@@ -19,7 +19,7 @@
 		from {
 			opacity: 0;
 		}
-		50%% {
+		50% {
 			opacity: 0.5;
 		}
 		to {
diff --git a/packages/svelte/tests/print/samples/svelte-body/input.svelte b/packages/svelte/tests/print/samples/svelte-body/input.svelte
new file mode 100644
index 0000000000..a4c26db5ce
--- /dev/null
+++ b/packages/svelte/tests/print/samples/svelte-body/input.svelte
@@ -0,0 +1 @@
+<svelte:body onmousemove={handleMousemove} />
diff --git a/packages/svelte/tests/print/samples/svelte-body/output.svelte b/packages/svelte/tests/print/samples/svelte-body/output.svelte
new file mode 100644
index 0000000000..e13eaae979
--- /dev/null
+++ b/packages/svelte/tests/print/samples/svelte-body/output.svelte
@@ -0,0 +1 @@
+<svelte:body onmousemove={handleMousemove}></svelte:body>

From f9440dc3ed28a9f1f518b0216d0e10fce00f1618 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Mon, 18 May 2026 18:44:05 +0200
Subject: [PATCH 014/222] Version Packages (#18239)

This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.


# Releases
## svelte@5.55.8

### Patch Changes

- fix(print): handle `svelte:body` and fix keyframe percentage
double-printing
([#18234](https://github.com/sveltejs/svelte/pull/18234))

- fix: execute uninitialized derived even if it's destroyed
([#18228](https://github.com/sveltejs/svelte/pull/18228))

- fix: use named symbols everywhere
([#18238](https://github.com/sveltejs/svelte/pull/18238))

- fix: don't run teardown effects when deriveds are unfreezed
([#18227](https://github.com/sveltejs/svelte/pull/18227))

- fix: unset context synchronously in `run`
([#18236](https://github.com/sveltejs/svelte/pull/18236))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .../fix-printer-svelte-body-keyframe-percent.md    |  5 -----
 .changeset/hungry-ads-beam.md                      |  5 -----
 .changeset/red-moles-talk.md                       |  5 -----
 .changeset/slimy-olives-cross.md                   |  5 -----
 .changeset/tangy-icons-dig.md                      |  5 -----
 packages/svelte/CHANGELOG.md                       | 14 ++++++++++++++
 packages/svelte/package.json                       |  2 +-
 packages/svelte/src/version.js                     |  2 +-
 8 files changed, 16 insertions(+), 27 deletions(-)
 delete mode 100644 .changeset/fix-printer-svelte-body-keyframe-percent.md
 delete mode 100644 .changeset/hungry-ads-beam.md
 delete mode 100644 .changeset/red-moles-talk.md
 delete mode 100644 .changeset/slimy-olives-cross.md
 delete mode 100644 .changeset/tangy-icons-dig.md

diff --git a/.changeset/fix-printer-svelte-body-keyframe-percent.md b/.changeset/fix-printer-svelte-body-keyframe-percent.md
deleted file mode 100644
index 6854468835..0000000000
--- a/.changeset/fix-printer-svelte-body-keyframe-percent.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-"svelte": patch
----
-
-fix(print): handle `svelte:body` and fix keyframe percentage double-printing
diff --git a/.changeset/hungry-ads-beam.md b/.changeset/hungry-ads-beam.md
deleted file mode 100644
index 260d177119..0000000000
--- a/.changeset/hungry-ads-beam.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: execute uninitialized derived even if it's destroyed
diff --git a/.changeset/red-moles-talk.md b/.changeset/red-moles-talk.md
deleted file mode 100644
index 7e09dc9b9a..0000000000
--- a/.changeset/red-moles-talk.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: use named symbols everywhere
diff --git a/.changeset/slimy-olives-cross.md b/.changeset/slimy-olives-cross.md
deleted file mode 100644
index 3309e2deab..0000000000
--- a/.changeset/slimy-olives-cross.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: don't run teardown effects when deriveds are unfreezed
diff --git a/.changeset/tangy-icons-dig.md b/.changeset/tangy-icons-dig.md
deleted file mode 100644
index 6d87912bbb..0000000000
--- a/.changeset/tangy-icons-dig.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: unset context synchronously in `run`
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 1255d8c6a0..36528c741b 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,19 @@
 # svelte
 
+## 5.55.8
+
+### Patch Changes
+
+- fix(print): handle `svelte:body` and fix keyframe percentage double-printing ([#18234](https://github.com/sveltejs/svelte/pull/18234))
+
+- fix: execute uninitialized derived even if it's destroyed ([#18228](https://github.com/sveltejs/svelte/pull/18228))
+
+- fix: use named symbols everywhere ([#18238](https://github.com/sveltejs/svelte/pull/18238))
+
+- fix: don't run teardown effects when deriveds are unfreezed ([#18227](https://github.com/sveltejs/svelte/pull/18227))
+
+- fix: unset context synchronously in `run` ([#18236](https://github.com/sveltejs/svelte/pull/18236))
+
 ## 5.55.7
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 2f0743641f..66a555880b 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.55.7",
+  "version": "5.55.8",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 6b0ed0aea8..446904cd14 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.55.7';
+export const VERSION = '5.55.8';
 export const PUBLIC_VERSION = '5';

From a5df6616ea6c8ee0984ff0fc7b04e51472f1d01d Mon Sep 17 00:00:00 2001
From: Sean Kenneth Doherty <Smaster7772@gmail.com>
Date: Mon, 18 May 2026 13:53:10 -0500
Subject: [PATCH 015/222] fix: avoid unnecessary stringify in server attributes
 (#18232)

### Before submitting the PR, please make sure you do the following

- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. Fixes #10031.
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).

### What this changes

Server attribute template generation currently wraps each dynamic
expression in `$.stringify`, even when the compiler can prove the
expression is a string or a known constant. This reuses the existing
scope evaluation metadata so server output can avoid `$.stringify` for
proven string/constant chunks while keeping it for possibly nullish
unknown values.

The updated snapshot covers a mixed attribute with a known string,
mutable state, `null`, numeric/undefined constants, a known
string-producing `typeof`, and an unknown prop value.

### Tests and linting

- [x] `pnpm test snapshot -t nullish-coallescence-omittance`
- [x] `pnpm test snapshot`
- [x] `pnpm --filter svelte check`
- [x] `pnpm lint`
- [x] `pnpm prettier --check .changeset/slow-bikes-serve.md`

---------

Co-authored-by: Rich Harris <hello@rich-harris.dev>
---
 .changeset/slow-bikes-serve.md                |  5 +++
 .../server/visitors/shared/utils.js           | 33 ++++++++++++-------
 .../_expected/client/index.svelte.js          | 13 ++++++--
 .../_expected/server/index.svelte.js          |  5 +--
 .../index.svelte                              |  4 ++-
 5 files changed, 42 insertions(+), 18 deletions(-)
 create mode 100644 .changeset/slow-bikes-serve.md

diff --git a/.changeset/slow-bikes-serve.md b/.changeset/slow-bikes-serve.md
new file mode 100644
index 0000000000..5e1d654353
--- /dev/null
+++ b/.changeset/slow-bikes-serve.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: inline primitive constants in attribute values during SSR
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
index 9b3ac3ad78..62e1c44094 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
@@ -229,18 +229,25 @@ export function build_attribute_value(
 				? node.data.replace(regex_whitespaces_strict, ' ')
 				: node.data;
 		} else {
-			expressions.push(
-				b.call(
-					'$.stringify',
-					transform(
-						/** @type {Expression} */ (context.visit(node.expression)),
-						node.metadata.expression
-					)
-				)
-			);
+			const evaluated = context.state.scope.evaluate(node.expression);
 
-			quasi = b.quasi('', i + 1 === value.length);
-			quasis.push(quasi);
+			if (evaluated.is_known) {
+				quasi.value.cooked += (evaluated.value ?? '') + '';
+			} else {
+				const expression = transform(
+					/** @type {Expression} */ (context.visit(node.expression)),
+					node.metadata.expression
+				);
+
+				expressions.push(
+					evaluated.is_string && evaluated.is_defined
+						? expression
+						: b.call('$.stringify', expression)
+				);
+
+				quasi = b.quasi('', i + 1 === value.length);
+				quasis.push(quasi);
+			}
 		}
 	}
 
@@ -248,7 +255,9 @@ export function build_attribute_value(
 		quasi.value.raw = sanitize_template_string(/** @type {string} */ (quasi.value.cooked));
 	}
 
-	return b.template(quasis, expressions);
+	return expressions.length > 0
+		? b.template(quasis, expressions)
+		: b.literal(/** @type {string} */ (quasi.value.cooked));
 }
 
 /**
diff --git a/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/client/index.svelte.js
index 5281a86582..837a7cd65a 100644
--- a/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/client/index.svelte.js
@@ -1,9 +1,9 @@
 import 'svelte/internal/disclose-version';
 import * as $ from 'svelte/internal/client';
 
-var root = $.from_html(`<h1></h1> <b></b> <button> </button> <h1></h1>`, 1);
+var root = $.from_html(`<h1></h1> <b></b> <button> </button> <h1></h1> <div></div>`, 1);
 
-export default function Nullish_coallescence_omittance($$anchor) {
+export default function Nullish_coallescence_omittance($$anchor, $$props) {
 	let name = 'world';
 	let count = $.state(0);
 	var fragment = root();
@@ -23,7 +23,14 @@ export default function Nullish_coallescence_omittance($$anchor) {
 	var h1_1 = $.sibling(button, 2);
 
 	h1_1.textContent = 'Hello, world';
-	$.template_effect(() => $.set_text(text, `Count is ${$.get(count) ?? ''}`));
+
+	var div = $.sibling(h1_1, 2);
+
+	$.template_effect(() => {
+		$.set_text(text, `Count is ${$.get(count) ?? ''}`);
+		$.set_attribute(div, 'title', `Hello, world ${$.get(count) ?? ''}  1  ${typeof $$props.value} ${$$props.value ?? ''}`);
+	});
+
 	$.delegated('click', button, () => $.update(count));
 	$.append($$anchor, fragment);
 }
diff --git a/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/server/index.svelte.js
index a7e580acb8..357a887c9b 100644
--- a/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/server/index.svelte.js
@@ -1,8 +1,9 @@
 import * as $ from 'svelte/internal/server';
 
-export default function Nullish_coallescence_omittance($$renderer) {
+export default function Nullish_coallescence_omittance($$renderer, $$props) {
 	let name = 'world';
 	let count = 0;
+	let { value } = $$props;
 
-	$$renderer.push(`<h1>Hello, world!</h1> <b>123</b> <button>Count is ${$.escape(count)}</button> <h1>Hello, world</h1>`);
+	$$renderer.push(`<h1>Hello, world!</h1> <b>123</b> <button>Count is ${$.escape(count)}</button> <h1>Hello, world</h1> <div${$.attr('title', `Hello, world ${$.stringify(count)}  1  ${typeof value} ${$.stringify(value)}`)}></div>`);
 }
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/index.svelte b/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/index.svelte
index a67c574fee..ed88f5a269 100644
--- a/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/index.svelte
+++ b/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/index.svelte
@@ -1,8 +1,10 @@
 <script>
     let name = 'world';
     let count = $state(0);
+    let { value } = $props();
 </script>
 <h1>Hello, {null}{name}!</h1>
 <b>{1 ?? 'stuff'}{2 ?? 'more stuff'}{3 ?? 'even more stuff'}</b>
 <button onclick={()=>count++}>Count is {count}</button>
-<h1>Hello, {name ?? 'earth' ?? null}</h1>
\ No newline at end of file
+<h1>Hello, {name ?? 'earth' ?? null}</h1>
+<div title="Hello, {name} {count} {null} {1} {undefined} {typeof value} {value}"></div>

From a63bf862c03d5c63b73e412f2ca952cb83d444d8 Mon Sep 17 00:00:00 2001
From: Mukunda Rao Katta <mukunda.vjcs6@gmail.com>
Date: Mon, 18 May 2026 12:42:20 -0700
Subject: [PATCH 016/222] docs: clarify context state getter pattern (#18226)

Closes #18022

This updates the context docs to show the getter pattern for state that
may be reassigned, such as primitive state. The new example passes a
function through context so children read the current value instead of
capturing the initial value.

This is a docs-only clarification and does not change runtime behavior.

Validation:

- `git diff --check`
- `pnpm exec prettier --check
documentation/docs/06-runtime/02-context.md`

Full `pnpm test`/`pnpm lint` were not run because this only changes
documentation.

---------

Co-authored-by: Rich Harris <hello@rich-harris.dev>
---
 documentation/docs/06-runtime/02-context.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/documentation/docs/06-runtime/02-context.md b/documentation/docs/06-runtime/02-context.md
index aee51c9a78..439272df8f 100644
--- a/documentation/docs/06-runtime/02-context.md
+++ b/documentation/docs/06-runtime/02-context.md
@@ -163,6 +163,8 @@ export const [getCounter, setCounter] = createContext<Counter>();
 
 Svelte will warn you if you get it wrong.
 
+Similarly, to pass primitive values through context, use functions as described in [Passing state into functions]($state#Passing-state-into-functions).
+
 ## Component testing
 
 When writing [component tests](testing#Unit-and-component-tests-with-Vitest-Component-testing), it can be useful to create a wrapper component that sets the context in order to check the behaviour of a component that uses it. As of version 5.49, you can do this sort of thing:

From be8ffeb2a4b0c36657fb5c1bdcf36971da814227 Mon Sep 17 00:00:00 2001
From: Kiwi <kiwisclubco@gmail.com>
Date: Tue, 19 May 2026 10:58:35 -0400
Subject: [PATCH 017/222] docs(contributing): fix grammar in Prioritization
 section (#18241)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Small typo in `CONTRIBUTING.md` — "the most important and active ones
repositories" reads like a leftover from an edit. Removed the dangling
"ones".

```diff
-PRs to the most important and active ones repositories get reviewed more quickly
+PRs to the most important and active repositories get reviewed more quickly
```
---
 CONTRIBUTING.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index e940252892..586c6fe6ae 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -43,7 +43,7 @@ The maintainers meet on the final Saturday of each month. While these meetings a
 
 ### Prioritization
 
-We do our best to review PRs and RFCs as they are sent, but it is difficult to keep up. We welcome help in reviewing PRs, RFCs, and issues. If an item aligns with the current priority on our [roadmap](https://svelte.dev/roadmap), it is more likely to be reviewed quickly. PRs to the most important and active ones repositories get reviewed more quickly while PRs to smaller inactive repos may sit for a bit before we periodically come by and review the pending PRs in a batch.
+We do our best to review PRs and RFCs as they are sent, but it is difficult to keep up. We welcome help in reviewing PRs, RFCs, and issues. If an item aligns with the current priority on our [roadmap](https://svelte.dev/roadmap), it is more likely to be reviewed quickly. PRs to the most important and active repositories get reviewed more quickly while PRs to smaller inactive repos may sit for a bit before we periodically come by and review the pending PRs in a batch.
 
 ## Bugs
 

From 000c594e05d27e3e56c08cf30274689615d99092 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Tue, 19 May 2026 22:16:03 +0200
Subject: [PATCH 018/222] fix: `{#await await ...}` and async dependencies
 fixes (#18243)

This started out as an investigation to get rid of the runtime code for
`{#await ...}` that deactivated a batch prior to reading the promise
function. That can result in a new batch being created if the promise
invocation happens to write a source.

Through that I discovered two other bugs:
1. The way we handle `{#await await ...}` was flawed around
SSR/hydration: On the server it would await the expression (which it
should not; `{#await await ...}` is kind of a weird special case here)
and during hydration it did not produce matching nodes, leading to
hydration fails.
2. When reading a dependency after an await expression which we add to
the current reaction, we did not deduplicate those reads. That can lead
to duplicate dependencies, which in turn can lead to bugs when
`remove_reaction` later runs. Conside this: You have `deps = [count,
unrelated, count]`. Now you do `remove_reactions(deps, 1)`, i.e. "remove
all reactions after the first one". That means the "disconnect these
from each other" logic runs for `count`, too, because it's also in the
third position, but that is wrong because it is also in the first
position, i.e. the connection should be kept.

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/clean-ties-start.md                |  5 +++
 .changeset/fair-otters-notice.md              |  5 +++
 .changeset/loud-phones-return.md              |  5 +++
 .../3-transform/client/visitors/AwaitBlock.js |  4 +-
 .../client/visitors/VariableDeclaration.js    | 18 +++++---
 .../3-transform/server/visitors/AwaitBlock.js |  9 +++-
 .../src/internal/client/dom/blocks/await.js   | 28 ++++++------
 .../svelte/src/internal/client/runtime.js     | 12 ++++--
 .../samples/async-await-block-2/_config.js    | 24 +++++++++++
 .../samples/async-await-block-2/main.svelte   | 22 ++++++++++
 .../async-duplicate-dependencies/_config.js   | 43 +++++++++++++++++++
 .../async-duplicate-dependencies/main.svelte  | 20 +++++++++
 12 files changed, 170 insertions(+), 25 deletions(-)
 create mode 100644 .changeset/clean-ties-start.md
 create mode 100644 .changeset/fair-otters-notice.md
 create mode 100644 .changeset/loud-phones-return.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-await-block-2/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-await-block-2/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-duplicate-dependencies/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-duplicate-dependencies/main.svelte

diff --git a/.changeset/clean-ties-start.md b/.changeset/clean-ties-start.md
new file mode 100644
index 0000000000..825ed675a5
--- /dev/null
+++ b/.changeset/clean-ties-start.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: don't unset batch when calling `{#await ...}` promise
diff --git a/.changeset/fair-otters-notice.md b/.changeset/fair-otters-notice.md
new file mode 100644
index 0000000000..eb5a181847
--- /dev/null
+++ b/.changeset/fair-otters-notice.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: promise-ify `{#await await ...}` expressions on the server and correctly hydrate them on the client
diff --git a/.changeset/loud-phones-return.md b/.changeset/loud-phones-return.md
new file mode 100644
index 0000000000..02f2b3a2e7
--- /dev/null
+++ b/.changeset/loud-phones-return.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: deduplicate dependencies that are added outside the init/update cycle
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/AwaitBlock.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/AwaitBlock.js
index 832c56818b..b8def178f2 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/AwaitBlock.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/AwaitBlock.js
@@ -71,14 +71,14 @@ export function AwaitBlock(node, context) {
 		'await'
 	);
 
-	if (node.metadata.expression.has_blockers()) {
+	if (node.metadata.expression.has_blockers() || node.metadata.expression.has_await) {
 		context.state.init.push(
 			b.stmt(
 				b.call(
 					'$.async',
 					context.state.node,
 					node.metadata.expression.blockers(),
-					b.array([]),
+					b.array([]), // {#await await ...} is special insofar that the await should not be waited on
 					b.arrow([context.state.node], b.block([stmt]))
 				)
 			)
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
index 16aa164d84..dffa79cd7a 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
@@ -386,13 +386,17 @@ export function VariableDeclaration(node, context) {
  * @param {Expression} value
  */
 function create_state_declarators(declarator, context, value) {
+	/**
+	 * @param {Expression} value
+	 * @param {string} name
+	 */
+	const mutable_source = (value, name) => {
+		const call = b.call('$.mutable_source', value, context.state.analysis.immutable && b.true);
+		return dev ? b.call('$.tag', call, b.literal(name)) : call;
+	};
+
 	if (declarator.id.type === 'Identifier') {
-		return [
-			b.declarator(
-				declarator.id,
-				b.call('$.mutable_source', value, context.state.analysis.immutable ? b.true : undefined)
-			)
-		];
+		return [b.declarator(declarator.id, mutable_source(value, declarator.id.name))];
 	}
 
 	const tmp = b.id(context.state.scope.generate('tmp'));
@@ -414,7 +418,7 @@ function create_state_declarators(declarator, context, value) {
 			return b.declarator(
 				path.node,
 				binding?.kind === 'state'
-					? b.call('$.mutable_source', value, context.state.analysis.immutable ? b.true : undefined)
+					? mutable_source(value, /** @type {Identifier} */ (path.node).name)
 					: value
 			);
 		})
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/AwaitBlock.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/AwaitBlock.js
index 84c2a81612..ba05ca1357 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/AwaitBlock.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/AwaitBlock.js
@@ -9,12 +9,19 @@ import { block_close, create_child_block } from './shared/utils.js';
  * @param {ComponentContext} context
  */
 export function AwaitBlock(node, context) {
+	let expression = /** @type {Expression} */ (context.visit(node.expression));
+	if (node.metadata.expression.has_await) {
+		// If this is an await expression, turn it into a IIFE so that the result is a promise.
+		// {#await await ...} is special insofar that the await should not be waited on.
+		expression = b.call(b.arrow([], expression, true));
+	}
+
 	/** @type {Statement} */
 	let statement = b.stmt(
 		b.call(
 			'$.await',
 			b.id('$$renderer'),
-			/** @type {Expression} */ (context.visit(node.expression)),
+			expression,
 			b.thunk(
 				node.pending ? /** @type {BlockStatement} */ (context.visit(node.pending)) : b.block([])
 			),
diff --git a/packages/svelte/src/internal/client/dom/blocks/await.js b/packages/svelte/src/internal/client/dom/blocks/await.js
index d6430547b5..194a7ccc0e 100644
--- a/packages/svelte/src/internal/client/dom/blocks/await.js
+++ b/packages/svelte/src/internal/client/dom/blocks/await.js
@@ -7,7 +7,8 @@ import {
 	hydrating,
 	skip_nodes,
 	set_hydrate_node,
-	set_hydrating
+	set_hydrating,
+	hydrate_node
 } from '../hydration.js';
 import { queue_micro_task } from '../task.js';
 import { HYDRATION_START_ELSE, UNINITIALIZED } from '../../../../constants.js';
@@ -15,6 +16,7 @@ import { is_runes } from '../../context.js';
 import { Batch, current_batch, flushSync, is_flushing_sync } from '../../reactivity/batch.js';
 import { BranchManager } from './branches.js';
 import { capture, unset_context } from '../../reactivity/async.js';
+import { DEV } from 'esm-env';
 
 const PENDING = 0;
 const THEN = 1;
@@ -42,16 +44,16 @@ export function await_block(node, get_input, pending_fn, then_fn, catch_fn) {
 	var value = runes ? source(v) : mutable_source(v, false, false);
 	var error = runes ? source(v) : mutable_source(v, false, false);
 
+	if (DEV) {
+		value.label = '{#await ...} value';
+		error.label = '{#await ...} error';
+	}
+
 	var branches = new BranchManager(node);
 
 	block(() => {
 		var batch = /** @type {Batch} */ (current_batch);
-
-		// we null out `current_batch` because otherwise `save(...)` will incorrectly restore it —
-		// the batch will already have been committed by the time it resolves
-		batch.deactivate();
 		var input = get_input();
-		batch.activate();
 
 		var destroyed = false;
 
@@ -79,15 +81,17 @@ export function await_block(node, get_input, pending_fn, then_fn, catch_fn) {
 				// We don't want to restore the previous batch here; {#await} blocks don't follow the async logic
 				// we have elsewhere, instead pending/resolve/fail states are each their own batch so to speak.
 				restore(false);
+				// ...but it might still be set here. That means a `save(...)` has restored it — but that batch will
+				// likely already have been committed by the time it resolves, and this resolve should be processed
+				// in a separate batch. We're not using batch.deactivate()/activate() above because get_input()
+				// could write to sources, which would then incorrectly create a new batch or could mess with
+				// async_derived expecting a current_batch to exist.
+				if (current_batch === batch) {
+					batch.deactivate();
+				}
 				// Make sure we have a batch, since the branch manager expects one to exist
 				Batch.ensure();
 
-				if (hydrating) {
-					// `restore()` could set `hydrating` to `true`, which we very much
-					// don't want — we want to restore everything _except_ this
-					set_hydrating(false);
-				}
-
 				try {
 					fn();
 				} finally {
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 033afe98dc..87abbd71b6 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -560,9 +560,15 @@ export function get(signal) {
 					}
 				}
 			} else {
-				// we're adding a dependency outside the init/update cycle
-				// (i.e. after an `await`)
-				(active_reaction.deps ??= []).push(signal);
+				// We're adding a dependency outside the init/update cycle (i.e. after an `await`).
+				// We have to deduplicate deps/reactions in this case or remove_reactions could
+				// disconnect deps/reactions that are actually still in use (if skip_deps says
+				// "disconnect all after this index" and some of the signals are also present in
+				// list prior to the cutoff index, i.e. that should be kept).
+				active_reaction.deps ??= [];
+				if (!includes.call(active_reaction.deps, signal)) {
+					active_reaction.deps.push(signal);
+				}
 
 				var reactions = signal.reactions;
 
diff --git a/packages/svelte/tests/runtime-runes/samples/async-await-block-2/_config.js b/packages/svelte/tests/runtime-runes/samples/async-await-block-2/_config.js
new file mode 100644
index 0000000000..0a927e64f6
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-await-block-2/_config.js
@@ -0,0 +1,24 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		await tick();
+		const [incremet, resolve] = target.querySelectorAll('button');
+
+		incremet.click();
+		await tick();
+		incremet.click();
+		await tick();
+		resolve.click();
+		await tick();
+		resolve.click();
+		await tick();
+		resolve.click();
+		await tick();
+		resolve.click();
+		await tick();
+
+		assert.htmlEqual(target.innerHTML, '<button>increment</button> <button>resolve</button> 4 4 1');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-await-block-2/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-await-block-2/main.svelte
new file mode 100644
index 0000000000..b619c6a949
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-await-block-2/main.svelte
@@ -0,0 +1,22 @@
+<script>
+	let count = $state(0);
+
+	const queue = [];
+
+	function push(v) {
+		if (v === 0) return v;
+
+		return new Promise((fulfil) => queue.push(() => fulfil(v)));
+	}
+
+	async function request(v) {
+		const result = $derived(await push(v));
+		return result + count;
+	}
+</script>
+
+<button onclick={() => count++}>increment</button>
+<button onclick={() => queue.shift()?.()}>resolve</button>
+{#await request(count) then result}{result}{/await}
+{#await await push(count) + count then result}{result}{/await}
+{#await await 1 then result}{result}{/await}
diff --git a/packages/svelte/tests/runtime-runes/samples/async-duplicate-dependencies/_config.js b/packages/svelte/tests/runtime-runes/samples/async-duplicate-dependencies/_config.js
new file mode 100644
index 0000000000..b7451282ac
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-duplicate-dependencies/_config.js
@@ -0,0 +1,43 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		await tick();
+		const [increment, resolve] = target.querySelectorAll('button');
+
+		increment.click();
+		await tick();
+		increment.click();
+		await tick();
+		resolve.click();
+		await tick();
+		resolve.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>increment</button>
+				<button>resolve</button>
+				4
+			`
+		);
+
+		increment.click();
+		await tick();
+		increment.click();
+		await tick();
+		resolve.click();
+		await tick();
+		resolve.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>increment</button>
+				<button>resolve</button>
+				8
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-duplicate-dependencies/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-duplicate-dependencies/main.svelte
new file mode 100644
index 0000000000..58a5848e3b
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-duplicate-dependencies/main.svelte
@@ -0,0 +1,20 @@
+<script>
+	let count = $state(0);
+
+	const queue = [];
+
+	function push(v) {
+		if (v === 0) return v;
+
+		return new Promise((fulfil) => queue.push(() => fulfil(v)));
+	}
+
+	async function request(v) {
+		const result = $derived(await push(v));
+		return result + count; // read existing dependency `count` once more
+	}
+</script>
+
+<button onclick={() => count++}>increment</button>
+<button onclick={() => queue.shift()?.()}>resolve</button>
+{await request(count)}

From d654db83ef3c299e0b7833e6c418ce02d6127abd Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Wed, 20 May 2026 03:04:31 +0200
Subject: [PATCH 019/222] fix: avoid false-positive batch invariant error
 (#18246)

Thanks to
https://github.com/sveltejs/svelte/issues/17940#issuecomment-4480016550
I was finally able to isolate and reproduce a false-positive invariant
error. I had a hunch this could happen and this shows it. Essentially,
you can end up in situations where two batches are scheduled to run in
the same microtask queue flush, and if the first rebases the second the
invariant will throw, which is wrong. We can avoid this by checking if a
decrement is queued.
---
 .changeset/slimy-frogs-share.md                  |  5 +++++
 .../src/internal/client/reactivity/batch.js      |  7 +++++--
 .../samples/async-pending-batch/_config.js       | 16 ++++++++++++++++
 .../samples/async-pending-batch/main.svelte      |  8 ++++++++
 4 files changed, 34 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/slimy-frogs-share.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-pending-batch/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-pending-batch/main.svelte

diff --git a/.changeset/slimy-frogs-share.md b/.changeset/slimy-frogs-share.md
new file mode 100644
index 0000000000..27a393d564
--- /dev/null
+++ b/.changeset/slimy-frogs-share.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: avoid false-positive batch invariant error
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index a5c9a51eec..ae4f5a6dac 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -679,7 +679,9 @@ export class Batch {
 					batch.discard();
 				}
 			} else if (sources.length > 0) {
-				if (DEV) {
+				// The microtask queue can contain the batch already scheduled to run right
+				// after this one is finished, so throwing the invariant would be wrong here.
+				if (DEV && !batch.#decrement_queued) {
 					invariant(batch.#roots.length === 0, 'Batch has scheduled roots');
 				}
 
@@ -732,7 +734,8 @@ export class Batch {
 				}
 
 				// Only apply and traverse when we know we triggered async work with marking the effects
-				if (batch.#roots.length > 0) {
+				// and know this won't run anyway right afterwards
+				if (batch.#roots.length > 0 && !batch.#decrement_queued) {
 					batch.apply();
 
 					for (var root of batch.#roots) {
diff --git a/packages/svelte/tests/runtime-runes/samples/async-pending-batch/_config.js b/packages/svelte/tests/runtime-runes/samples/async-pending-batch/_config.js
new file mode 100644
index 0000000000..e7359efa2d
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-pending-batch/_config.js
@@ -0,0 +1,16 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	// This test mainly checks that we don't run into the 'Batch has scheduled roots' invariant wrongly.
+	// It is crafted such that two batches are scheduled to run in the same microtask, and the first
+	// tries to rebase the second.
+	async test({ assert, target }) {
+		await tick();
+		const [run] = target.querySelectorAll('button');
+
+		run.click();
+		await tick();
+		assert.htmlEqual(target.innerHTML, '<button>run</button> none none 0');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-pending-batch/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-pending-batch/main.svelte
new file mode 100644
index 0000000000..19305cfb76
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-pending-batch/main.svelte
@@ -0,0 +1,8 @@
+<script>
+	let selectedId = $state(1);
+	let selectedOption = $derived(selectedId ? await selectedId : null);
+</script>
+
+<button onclick={() => (selectedId = null)}>run</button>
+
+{selectedId ?? "none"} {selectedOption ?? "none"} {$effect.pending()}

From ef319ed492869e075bfb29685a606bce4818adb7 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Wed, 20 May 2026 11:53:01 +0200
Subject: [PATCH 020/222] chore: bump acorn-typescript/esrap (#18248)

---
 packages/svelte/package.json                  |  4 +--
 .../svelte/scripts/process-messages/index.js  |  1 -
 pnpm-lock.yaml                                | 26 ++++++++++++-------
 3 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 66a555880b..f364b78e88 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -169,7 +169,7 @@
   "dependencies": {
     "@jridgewell/remapping": "^2.3.4",
     "@jridgewell/sourcemap-codec": "^1.5.0",
-    "@sveltejs/acorn-typescript": "^1.0.5",
+    "@sveltejs/acorn-typescript": "^1.0.10",
     "@types/estree": "^1.0.5",
     "@types/trusted-types": "^2.0.7",
     "acorn": "^8.12.1",
@@ -178,7 +178,7 @@
     "clsx": "^2.1.1",
     "devalue": "^5.8.1",
     "esm-env": "^1.2.1",
-    "esrap": "^2.2.4",
+    "esrap": "^2.2.9",
     "is-reference": "^3.0.3",
     "locate-character": "^3.0.0",
     "magic-string": "^0.30.11",
diff --git a/packages/svelte/scripts/process-messages/index.js b/packages/svelte/scripts/process-messages/index.js
index 1904f1dfb4..c8d7418db4 100644
--- a/packages/svelte/scripts/process-messages/index.js
+++ b/packages/svelte/scripts/process-messages/index.js
@@ -378,7 +378,6 @@ function run() {
 			};
 
 			const block = esrap.print(
-				// @ts-expect-error some bullshit
 				/** @type {ESTree.Program} */ ({ ...ast, body: [clone] }),
 				ts({ comments: [jsdoc_clone] })
 			).code;
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 1bfee5c769..25899b297d 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -75,8 +75,8 @@ importers:
         specifier: ^1.5.0
         version: 1.5.0
       '@sveltejs/acorn-typescript':
-        specifier: ^1.0.5
-        version: 1.0.5(acorn@8.16.0)
+        specifier: ^1.0.10
+        version: 1.0.10(acorn@8.16.0)
       '@types/estree':
         specifier: ^1.0.5
         version: 1.0.8
@@ -102,8 +102,8 @@ importers:
         specifier: ^1.2.1
         version: 1.2.1
       esrap:
-        specifier: ^2.2.4
-        version: 2.2.4
+        specifier: ^2.2.9
+        version: 2.2.9(@typescript-eslint/types@8.56.0)
       is-reference:
         specifier: ^3.0.3
         version: 3.0.3
@@ -1042,8 +1042,8 @@ packages:
     peerDependencies:
       eslint: '>=8.40.0'
 
-  '@sveltejs/acorn-typescript@1.0.5':
-    resolution: {integrity: sha512-IwQk4yfwLdibDlrXVE04jTZYlLnwsTT2PIOQQGNLWfjavGifnk1JD1LcZjZaBTRcxZu2FfPfNLOE04DSu9lqtQ==}
+  '@sveltejs/acorn-typescript@1.0.10':
+    resolution: {integrity: sha512-4WfKk68eTih+MiJD4fSbxN7E8kVBmTMPWHUPYjvl2N0rMs53YLTT8/YjKU5Dtnz5LqDjl7LEw4U7lXR2W3J5WA==}
     peerDependencies:
       acorn: ^8.9.0
 
@@ -1574,8 +1574,13 @@ packages:
     resolution: {integrity: sha512-Ap6G0WQwcU/LHsvLwON1fAQX9Zp0A2Y6Y/cJBl9r/JbW90Zyg4/zbG6zzKa2OTALELarYHmKu0GhpM5EO+7T0g==}
     engines: {node: '>=0.10'}
 
-  esrap@2.2.4:
-    resolution: {integrity: sha512-suICpxAmZ9A8bzJjEl/+rLJiDKC0X4gYWUxT6URAWBLvlXmtbZd5ySMu/N2ZGEtMCAmflUDPSehrP9BQcsGcSg==}
+  esrap@2.2.9:
+    resolution: {integrity: sha512-4KijP+NxCWthMCUC3qHbE6n4vCjqgJS1uAYKhuT/GWfFTf1Qyive2TgOjep+gzbSzRfnNyaN/UU9YmdOt8Eg0A==}
+    peerDependencies:
+      '@typescript-eslint/types': ^8.2.0
+    peerDependenciesMeta:
+      '@typescript-eslint/types':
+        optional: true
 
   esrecurse@4.3.0:
     resolution: {integrity: sha512-KmfKL3b6G+RXvP8N1vr3Tq1kL/oCFgn2NYXEtqP8/L3pKapUA4G8cFVaoF3SU323CD4XypR/ffioHmkti6/Tag==}
@@ -3392,7 +3397,7 @@ snapshots:
       eslint-visitor-keys: 3.4.3
       espree: 9.6.1
 
-  '@sveltejs/acorn-typescript@1.0.5(acorn@8.16.0)':
+  '@sveltejs/acorn-typescript@1.0.10(acorn@8.16.0)':
     dependencies:
       acorn: 8.16.0
 
@@ -4046,9 +4051,10 @@ snapshots:
     dependencies:
       estraverse: 5.3.0
 
-  esrap@2.2.4:
+  esrap@2.2.9(@typescript-eslint/types@8.56.0):
     dependencies:
       '@jridgewell/sourcemap-codec': 1.5.0
+    optionalDependencies:
       '@typescript-eslint/types': 8.56.0
 
   esrecurse@4.3.0:

From b65a3f3fc5e1607966e3e27f7e28fc691e622683 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Wed, 20 May 2026 12:07:18 +0200
Subject: [PATCH 021/222] Version Packages (#18240)

This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.


# Releases
## svelte@5.55.9

### Patch Changes

- fix: don't unset batch when calling `{#await ...}` promise
([#18243](https://github.com/sveltejs/svelte/pull/18243))

- fix: promise-ify `{#await await ...}` expressions on the server and
correctly hydrate them on the client
([#18243](https://github.com/sveltejs/svelte/pull/18243))

- fix: deduplicate dependencies that are added outside the init/update
cycle ([#18243](https://github.com/sveltejs/svelte/pull/18243))

- fix: avoid false-positive batch invariant error
([#18246](https://github.com/sveltejs/svelte/pull/18246))

- fix: inline primitive constants in attribute values during SSR
([#18232](https://github.com/sveltejs/svelte/pull/18232))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/clean-ties-start.md   |  5 -----
 .changeset/fair-otters-notice.md |  5 -----
 .changeset/loud-phones-return.md |  5 -----
 .changeset/slimy-frogs-share.md  |  5 -----
 .changeset/slow-bikes-serve.md   |  5 -----
 packages/svelte/CHANGELOG.md     | 14 ++++++++++++++
 packages/svelte/package.json     |  2 +-
 packages/svelte/src/version.js   |  2 +-
 8 files changed, 16 insertions(+), 27 deletions(-)
 delete mode 100644 .changeset/clean-ties-start.md
 delete mode 100644 .changeset/fair-otters-notice.md
 delete mode 100644 .changeset/loud-phones-return.md
 delete mode 100644 .changeset/slimy-frogs-share.md
 delete mode 100644 .changeset/slow-bikes-serve.md

diff --git a/.changeset/clean-ties-start.md b/.changeset/clean-ties-start.md
deleted file mode 100644
index 825ed675a5..0000000000
--- a/.changeset/clean-ties-start.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: don't unset batch when calling `{#await ...}` promise
diff --git a/.changeset/fair-otters-notice.md b/.changeset/fair-otters-notice.md
deleted file mode 100644
index eb5a181847..0000000000
--- a/.changeset/fair-otters-notice.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: promise-ify `{#await await ...}` expressions on the server and correctly hydrate them on the client
diff --git a/.changeset/loud-phones-return.md b/.changeset/loud-phones-return.md
deleted file mode 100644
index 02f2b3a2e7..0000000000
--- a/.changeset/loud-phones-return.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: deduplicate dependencies that are added outside the init/update cycle
diff --git a/.changeset/slimy-frogs-share.md b/.changeset/slimy-frogs-share.md
deleted file mode 100644
index 27a393d564..0000000000
--- a/.changeset/slimy-frogs-share.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: avoid false-positive batch invariant error
diff --git a/.changeset/slow-bikes-serve.md b/.changeset/slow-bikes-serve.md
deleted file mode 100644
index 5e1d654353..0000000000
--- a/.changeset/slow-bikes-serve.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: inline primitive constants in attribute values during SSR
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 36528c741b..1f3f9d1149 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,19 @@
 # svelte
 
+## 5.55.9
+
+### Patch Changes
+
+- fix: don't unset batch when calling `{#await ...}` promise ([#18243](https://github.com/sveltejs/svelte/pull/18243))
+
+- fix: promise-ify `{#await await ...}` expressions on the server and correctly hydrate them on the client ([#18243](https://github.com/sveltejs/svelte/pull/18243))
+
+- fix: deduplicate dependencies that are added outside the init/update cycle ([#18243](https://github.com/sveltejs/svelte/pull/18243))
+
+- fix: avoid false-positive batch invariant error ([#18246](https://github.com/sveltejs/svelte/pull/18246))
+
+- fix: inline primitive constants in attribute values during SSR ([#18232](https://github.com/sveltejs/svelte/pull/18232))
+
 ## 5.55.8
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index f364b78e88..b9bb48aa72 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.55.8",
+  "version": "5.55.9",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 446904cd14..ee05138797 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.55.8';
+export const VERSION = '5.55.9';
 export const PUBLIC_VERSION = '5';

From 65283bc13a54c41ee96940b559c1a027b8770882 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Wed, 20 May 2026 23:49:38 +0200
Subject: [PATCH 022/222] fix: transfer effects when merging batches (#18254)

An effect could be gated behind a branch. If we don't defer + transfer
them upon merge, the branch would still be marked clean but the effect
behind it is dirty but no longer reachable. It's not reachable via mark
either because that one only concerns itself with block/async effects,
and the branch gating the effect is not guaranteed to be touched by
that.

Fixes #18249

Little sad side-effect: Since we cannot reliably know _before_ traversal
if we have no blocking pending work left (the traversal could mark an if
block falsy which contains the last blocker), we gotta undo a
performance optimization.
---
 .changeset/evil-stars-wave.md                 |  5 +++
 .../src/internal/client/reactivity/batch.js   | 31 ++++++++++++-------
 .../async-batch-merge-effect/_config.js       | 25 +++++++++++++++
 .../async-batch-merge-effect/main.svelte      | 25 +++++++++++++++
 4 files changed, 74 insertions(+), 12 deletions(-)
 create mode 100644 .changeset/evil-stars-wave.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-batch-merge-effect/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-batch-merge-effect/main.svelte

diff --git a/.changeset/evil-stars-wave.md b/.changeset/evil-stars-wave.md
new file mode 100644
index 0000000000..b199afe1dd
--- /dev/null
+++ b/.changeset/evil-stars-wave.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: transfer effects when merging batches
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index ae4f5a6dac..2803ffc84c 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -289,19 +289,19 @@ export class Batch {
 			}
 		}
 
-		// we only reschedule previously-deferred effects if we expect
-		// to be able to run them after processing the batch
-		if (!this.#is_deferred()) {
-			for (const e of this.#dirty_effects) {
-				this.#maybe_dirty_effects.delete(e);
-				set_signal_status(e, DIRTY);
-				this.schedule(e);
-			}
+		// We always reschedule previously-deferred effects, not just when
+		// #is_deferred() is true, because traversing the tree could make
+		// an if block that contains the last blocking pending effect falsy,
+		// causing the block to no longer be deferred.
+		for (const e of this.#dirty_effects) {
+			this.#maybe_dirty_effects.delete(e);
+			set_signal_status(e, DIRTY);
+			this.schedule(e);
+		}
 
-			for (const e of this.#maybe_dirty_effects) {
-				set_signal_status(e, MAYBE_DIRTY);
-				this.schedule(e);
-			}
+		for (const e of this.#maybe_dirty_effects) {
+			set_signal_status(e, MAYBE_DIRTY);
+			this.schedule(e);
 		}
 
 		const roots = this.#roots;
@@ -362,6 +362,10 @@ export class Batch {
 		const earlier_batch = this.#find_earlier_batch();
 
 		if (earlier_batch) {
+			// If this batch collected deferred effects during traversal, they still need
+			// to run after being merged into the earlier batch.
+			this.#defer_effects(render_effects);
+			this.#defer_effects(effects);
 			earlier_batch.#merge(this);
 			return;
 		}
@@ -503,6 +507,9 @@ export class Batch {
 			if (d) deferred.promise.then(d.resolve);
 		}
 
+		// Mark is not guaranteed not touch these, so we transfer them
+		this.transfer_effects(batch.#dirty_effects, batch.#maybe_dirty_effects);
+
 		/**
 		 * mark all effects that depend on `batch.current`, except the
 		 * async effects that we just resolved (TODO unless they depend
diff --git a/packages/svelte/tests/runtime-runes/samples/async-batch-merge-effect/_config.js b/packages/svelte/tests/runtime-runes/samples/async-batch-merge-effect/_config.js
new file mode 100644
index 0000000000..c2be623de2
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-batch-merge-effect/_config.js
@@ -0,0 +1,25 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		await tick();
+		const [x, x_y, pop] = target.querySelectorAll('button');
+
+		x.click();
+		await tick();
+		x_y.click();
+		await tick();
+		pop.click();
+		await tick();
+		pop.click();
+		await tick();
+		pop.click();
+		await tick();
+
+		assert.htmlEqual(
+			target.innerHTML,
+			'<button>x</button> <button>x/y</button> <button>pop</button> 2 1 1'
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-batch-merge-effect/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-batch-merge-effect/main.svelte
new file mode 100644
index 0000000000..61efd4fca0
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-batch-merge-effect/main.svelte
@@ -0,0 +1,25 @@
+<script>
+	let x = $state(0);
+	let y = $state(0);
+
+	const queued = [];
+
+	function push(v) {
+		if (v === 0) return v;
+
+		return new Promise((fulfil) => {
+			queued.push(() => fulfil(v));
+		});
+	}
+</script>
+
+<button onclick={() => x++}>x</button>
+<button onclick={() => {x++;y++}}>x/y</button>
+<button onclick={() => (queued.pop()?.())}>pop</button>
+
+{await push(x)} {await push(y)}
+
+{#if true}
+	{y}
+{/if}
+

From 91a42e2ed6bda52205b269d28e70b9d15cd87292 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Thu, 21 May 2026 20:25:51 +0200
Subject: [PATCH 023/222] fix: correctly coordinate component-level effects
 inside async blocks (#18260)

While looking at the reproduction in
https://github.com/sveltejs/svelte/issues/18221#issuecomment-4497918414
I immediately got greeted with a runtime error when running it in the
playground (weirdly not in the Stackblitz version). The error was that a
component expected a binding to be set in onMount, but the timing of
onMount was wrong.

Turns out it's because our logic to determine whether or not to defer
top level effects is flawed. `REACTION_RAN`, which was used previously,
is already set if the initialized component is inside an async block. We
instead check for `component_context.i` which is set to `true` on
`pop()`.
---
 .changeset/tasty-tires-wait.md                         |  5 +++++
 .../svelte/src/internal/client/reactivity/effects.js   |  7 +++++--
 .../samples/async-effect-mount-timing/Child.svelte     |  6 ++++++
 .../samples/async-effect-mount-timing/_config.js       | 10 ++++++++++
 .../samples/async-effect-mount-timing/main.svelte      |  5 +++++
 5 files changed, 31 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/tasty-tires-wait.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-effect-mount-timing/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-effect-mount-timing/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-effect-mount-timing/main.svelte

diff --git a/.changeset/tasty-tires-wait.md b/.changeset/tasty-tires-wait.md
new file mode 100644
index 0000000000..0f3fd2d671
--- /dev/null
+++ b/.changeset/tasty-tires-wait.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: correctly coordinate component-level effects inside async blocks
diff --git a/packages/svelte/src/internal/client/reactivity/effects.js b/packages/svelte/src/internal/client/reactivity/effects.js
index 5bdba037b1..1bbda86fa7 100644
--- a/packages/svelte/src/internal/client/reactivity/effects.js
+++ b/packages/svelte/src/internal/client/reactivity/effects.js
@@ -20,7 +20,6 @@ import {
 	EFFECT,
 	DESTROYED,
 	INERT,
-	REACTION_RAN,
 	BLOCK_EFFECT,
 	ROOT_EFFECT,
 	EFFECT_TRANSPARENT,
@@ -213,7 +212,11 @@ export function user_effect(fn) {
 	// Non-nested `$effect(...)` in a component should be deferred
 	// until the component is mounted
 	var flags = /** @type {Effect} */ (active_effect).f;
-	var defer = !active_reaction && (flags & BRANCH_EFFECT) !== 0 && (flags & REACTION_RAN) === 0;
+	var defer =
+		!active_reaction &&
+		(flags & BRANCH_EFFECT) !== 0 &&
+		component_context !== null &&
+		!component_context.i;
 
 	if (defer) {
 		// Top-level `$effect(...)` in an unmounted component — defer until mount
diff --git a/packages/svelte/tests/runtime-runes/samples/async-effect-mount-timing/Child.svelte b/packages/svelte/tests/runtime-runes/samples/async-effect-mount-timing/Child.svelte
new file mode 100644
index 0000000000..18856d71e1
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-effect-mount-timing/Child.svelte
@@ -0,0 +1,6 @@
+<script>
+	let x;
+	$effect(() => console.log(!!x))
+</script>
+
+<div bind:this={x}></div>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-effect-mount-timing/_config.js b/packages/svelte/tests/runtime-runes/samples/async-effect-mount-timing/_config.js
new file mode 100644
index 0000000000..7a6e436825
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-effect-mount-timing/_config.js
@@ -0,0 +1,10 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	// Test that $effect/onMount etc at the top level of components are correctly deferred/coordinated if inside an async block
+	async test({ assert, logs }) {
+		await tick();
+		assert.deepEqual(logs, [true]);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-effect-mount-timing/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-effect-mount-timing/main.svelte
new file mode 100644
index 0000000000..934d9d7f5b
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-effect-mount-timing/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Child from './Child.svelte';
+</script>
+
+<Child foo={await 1} />

From 4656e6895dde764e99c01d9dd86379df2c881c8a Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Thu, 21 May 2026 20:26:09 +0200
Subject: [PATCH 024/222] fix: make unnecessary commit work less likely
 (#18263)

While looking at
https://github.com/sveltejs/svelte/issues/18221#issuecomment-4497918414
and trying to understand how the invariant can happen I noticed that we
are not correctly filtering during commit.
- we were not ignoring deriveds
- we were not comparing the correct values (checking `source.v` instead
of the saved value) and not checking if their "is a derived" state
differs

I'm not able to come up with a test where something fails without these
(possibly because it's more about an optimization to do less reruns and
not about correctness) fixes, but they do make sense.
---
 .changeset/tired-socks-brake.md               |  5 +++++
 .../src/internal/client/reactivity/batch.js   | 19 ++++++++++++-------
 2 files changed, 17 insertions(+), 7 deletions(-)
 create mode 100644 .changeset/tired-socks-brake.md

diff --git a/.changeset/tired-socks-brake.md b/.changeset/tired-socks-brake.md
new file mode 100644
index 0000000000..1d302ffa60
--- /dev/null
+++ b/.changeset/tired-socks-brake.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: make unnecessary commit work less likely
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 2803ffc84c..4952001dd6 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -677,8 +677,10 @@ export class Batch {
 
 			if (!batch.#started) continue;
 
-			// Re-run async/block effects that depend on distinct values changed in both batches
-			var others = [...batch.current.keys()].filter((s) => !this.current.has(s));
+			// Re-run async/block effects that depend on distinct values changed in both batches (ignoring deriveds)
+			var others = [...batch.current.keys()].filter(
+				(s) => !(/** @type {[any, boolean]} */ (batch.current.get(s))[1]) && !this.current.has(s)
+			);
 
 			if (others.length === 0) {
 				if (is_earlier) {
@@ -718,11 +720,14 @@ export class Batch {
 				}
 
 				checked = new Map();
-				var current_unequal = [...batch.current.keys()].filter((c) =>
-					this.current.has(c)
-						? /** @type {[any, boolean]} */ (this.current.get(c))[0] !== c.v
-						: true
-				);
+				var current_unequal = [...batch.current]
+					.filter(([c, v1]) => {
+						const v2 = this.current.get(c);
+						if (!v2) return true;
+						// Either their values are different or one is a derived but not the other
+						return v2[0] !== v1[0] || v2[1] !== v1[1];
+					})
+					.map(([c]) => c);
 
 				if (current_unequal.length > 0) {
 					for (const effect of this.#new_effects) {

From a6002b587c9d2f40fe2dc48391c372360abbaf0f Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Thu, 21 May 2026 20:26:47 +0200
Subject: [PATCH 025/222] fix: unlink errored and otherwise finished batch
 (#18264)

This fixes the issue in
https://github.com/sveltejs/svelte/issues/18221#issuecomment-4497918414
where an error can create follup-up invariant errors. The batch errors,
has no chance to run otherwise (no more pending work) and is therefore
"dead". That means we need to unlink it otherwise it's becoming a
"zombie" and hangs around, causing unnecessary and potentially buggy (as
seen in the reproduction) merge/commit work.

I was not able to reduce the reproduction down to a test case that fails
without the fix, but it does make a related error test from #17888 work
more correctly.
---
 .changeset/beige-bobcats-eat.md                             | 5 +++++
 packages/svelte/src/internal/client/reactivity/batch.js     | 6 ++++++
 .../tests/runtime-runes/samples/error-recovery/_config.js   | 6 +++---
 3 files changed, 14 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/beige-bobcats-eat.md

diff --git a/.changeset/beige-bobcats-eat.md b/.changeset/beige-bobcats-eat.md
new file mode 100644
index 0000000000..95390c3c2e
--- /dev/null
+++ b/.changeset/beige-bobcats-eat.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: unlink errored and otherwise finished batch
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 4952001dd6..b9721b6243 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -326,6 +326,12 @@ export class Batch {
 				this.#traverse(root, effects, render_effects);
 			} catch (e) {
 				reset_all(root);
+				// If there's no async work left, this branch is now dead and needs
+				// to be unlinked to not become a zombie that is never cleaned up.
+				// See https://github.com/sveltejs/svelte/issues/18221#issuecomment-4497918414
+				// for a (non-minimal) reproduction that demonstrates a case where this is necessary
+				// to not get follow-up false-positives via "batch has scheduled roots" invariant errors.
+				if (!this.#is_deferred()) this.#unlink();
 				throw e;
 			}
 		}
diff --git a/packages/svelte/tests/runtime-runes/samples/error-recovery/_config.js b/packages/svelte/tests/runtime-runes/samples/error-recovery/_config.js
index 52c1bbd1bf..1f80251806 100644
--- a/packages/svelte/tests/runtime-runes/samples/error-recovery/_config.js
+++ b/packages/svelte/tests/runtime-runes/samples/error-recovery/_config.js
@@ -2,7 +2,7 @@ import { flushSync } from 'svelte';
 import { test } from '../../test';
 
 export default test({
-	async test({ assert, target, compileOptions }) {
+	async test({ assert, target }) {
 		const [toggle, increment] = target.querySelectorAll('button');
 
 		flushSync(() => increment.click());
@@ -25,8 +25,8 @@ export default test({
 			`
 				<button>toggle</button>
 				<button>count: 2</button>
-				<p>show: ${compileOptions.experimental?.async ? 'false' : 'true'}</p>
-			`
+				<p>show: true</p>
+			` // show: false would also be fine; this is more about ensuring that things continue to work _somehow_
 		);
 	}
 });

From 078f901f611237d4c6fed16ef894f33572f9ccba Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Thu, 21 May 2026 20:27:13 +0200
Subject: [PATCH 026/222] fix: catch rejected promises while merging/committing
 (#18266)

A committing/merging batch can have promises that were rejected (e.g. as
obsolete). We gotta "forward" this rejection, too, instead of just the
successful promise. At best it results in a uncaught rejection
(`async-branch-merge-obsolete`), at worst it means error boundaries are
not correctly displayed (`async-later-promise-fails-first`).

Solves the reproduction in
https://github.com/sveltejs/svelte/issues/18221#issuecomment-4507803845
---
 .changeset/true-pigs-go.md                    |  5 ++++
 .../src/internal/client/reactivity/batch.js   |  4 +--
 .../async-branch-merge-obsolete/_config.js    | 17 +++++++++++++
 .../async-branch-merge-obsolete/main.svelte   | 21 ++++++++++++++++
 .../_config.js                                | 25 +++++++++++++++++++
 .../main.svelte                               | 22 ++++++++++++++++
 6 files changed, 92 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/true-pigs-go.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-branch-merge-obsolete/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-branch-merge-obsolete/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-later-promise-fails-first/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-later-promise-fails-first/main.svelte

diff --git a/.changeset/true-pigs-go.md b/.changeset/true-pigs-go.md
new file mode 100644
index 0000000000..b4900b38fa
--- /dev/null
+++ b/.changeset/true-pigs-go.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: catch rejected promises while merging/committing
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index b9721b6243..82c97cf95c 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -510,7 +510,7 @@ export class Batch {
 
 		for (const [effect, deferred] of batch.async_deriveds) {
 			const d = this.async_deriveds.get(effect);
-			if (d) deferred.promise.then(d.resolve);
+			if (d) deferred.promise.then(d.resolve).catch(d.reject);
 		}
 
 		// Mark is not guaranteed not touch these, so we transfer them
@@ -677,7 +677,7 @@ export class Batch {
 				// immediately resolving them? Likely not because of how this.apply() works.
 				for (const [effect, deferred] of this.async_deriveds) {
 					const d = batch.async_deriveds.get(effect);
-					if (d) deferred.promise.then(d.resolve);
+					if (d) deferred.promise.then(d.resolve).catch(d.reject);
 				}
 			}
 
diff --git a/packages/svelte/tests/runtime-runes/samples/async-branch-merge-obsolete/_config.js b/packages/svelte/tests/runtime-runes/samples/async-branch-merge-obsolete/_config.js
new file mode 100644
index 0000000000..faf1ff7f6b
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-branch-merge-obsolete/_config.js
@@ -0,0 +1,17 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		await tick();
+		const [increment] = target.querySelectorAll('button');
+
+		increment.click();
+		await tick();
+		increment.click();
+		await tick();
+		increment.click();
+		await tick();
+		assert.htmlEqual(target.innerHTML, '<button>increment</button> done');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-branch-merge-obsolete/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-branch-merge-obsolete/main.svelte
new file mode 100644
index 0000000000..4780442293
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-branch-merge-obsolete/main.svelte
@@ -0,0 +1,21 @@
+<script>
+	let count = $state(0);
+
+	const queued = [];
+
+	function push(v) {
+		if (v === 0) return v;
+
+		return new Promise((fulfil) => {
+			queued.push(() => fulfil(v));
+		});
+	}
+</script>
+
+<button onclick={() => count++}>increment</button>
+
+{#if count < 3}
+	{await push(count)}
+{:else}
+	done
+{/if}
diff --git a/packages/svelte/tests/runtime-runes/samples/async-later-promise-fails-first/_config.js b/packages/svelte/tests/runtime-runes/samples/async-later-promise-fails-first/_config.js
new file mode 100644
index 0000000000..5e18c953c7
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-later-promise-fails-first/_config.js
@@ -0,0 +1,25 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		await tick();
+		const [increment, pop] = target.querySelectorAll('button');
+
+		increment.click();
+		await tick();
+		increment.click();
+		await tick();
+		increment.click();
+		await tick();
+		pop.click();
+		await tick();
+		assert.htmlEqual(target.innerHTML, '<button>increment</button><button>pop</button> failed');
+
+		pop.click();
+		await tick();
+		pop.click();
+		await tick();
+		assert.htmlEqual(target.innerHTML, '<button>increment</button><button>pop</button> failed');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-later-promise-fails-first/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-later-promise-fails-first/main.svelte
new file mode 100644
index 0000000000..3293e4ab88
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-later-promise-fails-first/main.svelte
@@ -0,0 +1,22 @@
+<script>
+	let count = $state(0);
+
+	const queued = [];
+
+	function push(v) {
+		if (v === 0) return v;
+
+		return new Promise((fulfil,reject) => {
+			queued.push(() => v === 3 ? reject('boom') : fulfil(v));
+		});
+	}
+</script>
+
+<button onclick={() => count++}>increment</button>
+<button onclick={() => queued.pop()?.()}>pop</button>
+
+<svelte:boundary>
+	{await push(count)}
+
+	{#snippet failed()}failed{/snippet}
+</svelte:boundary>

From 04d408b29d059f131766448265768ce705801aaf Mon Sep 17 00:00:00 2001
From: Mathias Picker <48158184+MathiasWP@users.noreply.github.com>
Date: Thu, 21 May 2026 21:53:34 +0200
Subject: [PATCH 027/222] perf: walk composedPath() directly in delegated event
 propagation (#18268)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

## Summary

The propagation walk in `handle_event_propagation` already calls
`event.composedPath()` at the start to find the entry index, but then
re-derives the same chain step-by-step via `current_target.assignedSlot
|| current_target.parentNode || .host`. Three property reads per
iteration is measurable on the hot event path.

Walk the captured `path` array by index instead.

## Notes on behavior

`composedPath()` is the spec-compliant snapshot of the dispatch chain:
- Same shadow-DOM crossings (slots and shadow roots are included for
composed events).
- Same `host` traversal (composed-path crosses shadow boundaries when
appropriate).
- Differs from the previous walk in one edge case: if a handler removes
a parent mid-dispatch, the snapshot-based walk continues through the
captured chain (matches native browser semantics — the previous
`parentNode` walk would have stopped at a null parent).

## Performance

Measured in real Chromium on a click through a 30-deep tree with five
delegated handlers: **~245k hz → ~277k hz** (~+13%, ~−12% per-event
time).

## Test plan

- [x] All 6006 runtime tests pass (runtime-runes + runtime-legacy +
runtime-browser)
- [x] Native shadow-DOM event tests (in runtime-browser) pass unchanged

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 .changeset/event-walk-composed-path.md            |  5 +++++
 .../src/internal/client/dom/elements/events.js    | 15 +++++----------
 2 files changed, 10 insertions(+), 10 deletions(-)
 create mode 100644 .changeset/event-walk-composed-path.md

diff --git a/.changeset/event-walk-composed-path.md b/.changeset/event-walk-composed-path.md
new file mode 100644
index 0000000000..8b24573930
--- /dev/null
+++ b/.changeset/event-walk-composed-path.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+perf: walk composedPath() directly in delegated event propagation
diff --git a/packages/svelte/src/internal/client/dom/elements/events.js b/packages/svelte/src/internal/client/dom/elements/events.js
index 5aa41e1c4d..45e042a8c6 100644
--- a/packages/svelte/src/internal/client/dom/elements/events.js
+++ b/packages/svelte/src/internal/client/dom/elements/events.js
@@ -257,12 +257,7 @@ export function handle_event_propagation(event) {
 		var other_errors = [];
 
 		while (current_target !== null) {
-			/** @type {null | Element} */
-			var parent_element =
-				current_target.assignedSlot ||
-				current_target.parentNode ||
-				/** @type {any} */ (current_target).host ||
-				null;
+			if (current_target === handler_element) break;
 
 			try {
 				// @ts-expect-error
@@ -284,10 +279,10 @@ export function handle_event_propagation(event) {
 					throw_error = error;
 				}
 			}
-			if (event.cancelBubble || parent_element === handler_element || parent_element === null) {
-				break;
-			}
-			current_target = parent_element;
+			if (event.cancelBubble) break;
+
+			path_idx++;
+			current_target = path_idx < path.length ? /** @type {Element} */ (path[path_idx]) : null;
 		}
 
 		if (throw_error) {

From 8b961be0b190078815219e614b739b170e1087b1 Mon Sep 17 00:00:00 2001
From: Puneet Dixit <puneetdixit4321@gmail.com>
Date: Fri, 22 May 2026 01:54:11 +0530
Subject: [PATCH 028/222] fix: remove raw-text hydration markers (#18269)

Fixes #14413.

This keeps the temporary raw-text hydration sentinel used by dynamic
`<svelte:element>` from becoming part of the final DOM. Hydration still
gets a marker to advance through for raw-text children, but the marker
is removed after the child renderer runs, so `<style>` and `<script>`
contents stay identical to SSR output.

Tests:
- `pnpm test hydration -t svelte-head-dynamic-style`
- `pnpm test hydration`
- `pnpm test runtime-runes -t svelte-element`
- `pnpm lint`
- `git diff --check`

---------

Co-authored-by: Puneet Dixit <236133619+puneetdixit200@users.noreply.github.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/gentle-styles-hydrate.md                      | 5 +++++
 .../src/internal/client/dom/blocks/svelte-element.js     | 8 +++++---
 .../svelte/tests/hydration/samples/script/_expected.html | 2 +-
 .../samples/svelte-head-dynamic-style/_config.js         | 7 +++++++
 .../samples/svelte-head-dynamic-style/main.svelte        | 9 +++++++++
 5 files changed, 27 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/gentle-styles-hydrate.md
 create mode 100644 packages/svelte/tests/hydration/samples/svelte-head-dynamic-style/_config.js
 create mode 100644 packages/svelte/tests/hydration/samples/svelte-head-dynamic-style/main.svelte

diff --git a/.changeset/gentle-styles-hydrate.md b/.changeset/gentle-styles-hydrate.md
new file mode 100644
index 0000000000..f63d4e274c
--- /dev/null
+++ b/.changeset/gentle-styles-hydrate.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: remove temporary raw-text hydration markers
diff --git a/packages/svelte/src/internal/client/dom/blocks/svelte-element.js b/packages/svelte/src/internal/client/dom/blocks/svelte-element.js
index 6df020d2d7..84217c57e3 100644
--- a/packages/svelte/src/internal/client/dom/blocks/svelte-element.js
+++ b/packages/svelte/src/internal/client/dom/blocks/svelte-element.js
@@ -88,9 +88,11 @@ export function element(node, get_tag, is_svg, render_fn, get_namespace, locatio
 				assign_nodes(element, element);
 
 				if (render_fn) {
+					var tmp_comment = null;
+
 					if (hydrating && is_raw_text_element(next_tag)) {
-						// prevent hydration glitches
-						element.append(document.createComment(''));
+						// prevent hydration glitches (code just below expects an anchor)
+						element.append((tmp_comment = document.createComment('')));
 					}
 
 					// If hydrating, use the existing ssr comment as the anchor so that the
@@ -114,7 +116,7 @@ export function element(node, get_tag, is_svg, render_fn, get_namespace, locatio
 					// contains children, it's a user error (which is warned on elsewhere)
 					// and the DOM will be silently discarded
 					render_fn(element, child_anchor);
-
+					tmp_comment?.remove();
 					set_animation_effect_override(null);
 				}
 
diff --git a/packages/svelte/tests/hydration/samples/script/_expected.html b/packages/svelte/tests/hydration/samples/script/_expected.html
index b3a4d92219..3a19aa3b9b 100644
--- a/packages/svelte/tests/hydration/samples/script/_expected.html
+++ b/packages/svelte/tests/hydration/samples/script/_expected.html
@@ -1 +1 @@
-<!--[--><!----><script>{}<!----></script><!----><!--]-->
+<!--[--><!----><script>{}</script><!----><!--]-->
diff --git a/packages/svelte/tests/hydration/samples/svelte-head-dynamic-style/_config.js b/packages/svelte/tests/hydration/samples/svelte-head-dynamic-style/_config.js
new file mode 100644
index 0000000000..50e03336c6
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/svelte-head-dynamic-style/_config.js
@@ -0,0 +1,7 @@
+import { test } from '../../test';
+
+export default test({
+	props: {
+		css: 'body { color: red; }'
+	}
+});
diff --git a/packages/svelte/tests/hydration/samples/svelte-head-dynamic-style/main.svelte b/packages/svelte/tests/hydration/samples/svelte-head-dynamic-style/main.svelte
new file mode 100644
index 0000000000..7eacce62c2
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/svelte-head-dynamic-style/main.svelte
@@ -0,0 +1,9 @@
+<script>
+	let { css } = $props();
+</script>
+
+<svelte:head>
+	<svelte:element this="style" type="text/css">{css}</svelte:element>
+</svelte:head>
+
+<p>content</p>

From bb69f9c44cdd065ce69e5da7ab912e6c40fac77c Mon Sep 17 00:00:00 2001
From: wheelman <alcaminohot09@gmail.com>
Date: Fri, 22 May 2026 14:40:38 +0530
Subject: [PATCH 029/222] fix: declare `let:` directives before `{@const}` on
 slotted elements (#18271)

Fixes #18119 (missed a spot in #16985)
---
 .changeset/quiet-rivers-melt.md                   |  5 +++++
 .../3-transform/client/visitors/RegularElement.js |  4 ++--
 .../Nested.svelte                                 |  7 +++++++
 .../_config.js                                    | 15 +++++++++++++++
 .../main.svelte                                   | 10 ++++++++++
 5 files changed, 39 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/quiet-rivers-melt.md
 create mode 100644 packages/svelte/tests/runtime-legacy/samples/let-directive-and-const-tag-slotted/Nested.svelte
 create mode 100644 packages/svelte/tests/runtime-legacy/samples/let-directive-and-const-tag-slotted/_config.js
 create mode 100644 packages/svelte/tests/runtime-legacy/samples/let-directive-and-const-tag-slotted/main.svelte

diff --git a/.changeset/quiet-rivers-melt.md b/.changeset/quiet-rivers-melt.md
new file mode 100644
index 0000000000..7ce1b9b2d3
--- /dev/null
+++ b/.changeset/quiet-rivers-melt.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: declare `let:` directives before `{@const}` declarations on slotted elements
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
index 0579d80b74..1e6230a1f6 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
@@ -201,8 +201,8 @@ export function RegularElement(node, context) {
 		}
 	}
 
-	// Let bindings first, they can be used on attributes
-	context.state.init.push(...lets);
+	// Let bindings first, they can be used on attributes and `{@const}` declarations
+	context.state.let_directives.push(...lets);
 
 	const node_id = context.state.node;
 
diff --git a/packages/svelte/tests/runtime-legacy/samples/let-directive-and-const-tag-slotted/Nested.svelte b/packages/svelte/tests/runtime-legacy/samples/let-directive-and-const-tag-slotted/Nested.svelte
new file mode 100644
index 0000000000..417e539554
--- /dev/null
+++ b/packages/svelte/tests/runtime-legacy/samples/let-directive-and-const-tag-slotted/Nested.svelte
@@ -0,0 +1,7 @@
+<script>
+	export let things;
+</script>
+
+{#each things as thing}
+	<slot name="foo" {thing} />
+{/each}
diff --git a/packages/svelte/tests/runtime-legacy/samples/let-directive-and-const-tag-slotted/_config.js b/packages/svelte/tests/runtime-legacy/samples/let-directive-and-const-tag-slotted/_config.js
new file mode 100644
index 0000000000..bbbcd9ad12
--- /dev/null
+++ b/packages/svelte/tests/runtime-legacy/samples/let-directive-and-const-tag-slotted/_config.js
@@ -0,0 +1,15 @@
+import { test } from '../../test';
+
+// `let:` directives on a slotted element must be declared before sibling `{@const}`
+// declarations that capture them. In dev mode the `{@const}` derived is read eagerly,
+// so a wrong declaration order throws "Cannot access '...' before initialization".
+export default test({
+	compileOptions: {
+		dev: true
+	},
+
+	html: `
+		<div slot="foo"><span>1</span></div>
+		<div slot="foo"><span>2</span></div>
+	`
+});
diff --git a/packages/svelte/tests/runtime-legacy/samples/let-directive-and-const-tag-slotted/main.svelte b/packages/svelte/tests/runtime-legacy/samples/let-directive-and-const-tag-slotted/main.svelte
new file mode 100644
index 0000000000..e2530ef015
--- /dev/null
+++ b/packages/svelte/tests/runtime-legacy/samples/let-directive-and-const-tag-slotted/main.svelte
@@ -0,0 +1,10 @@
+<script>
+	import Nested from './Nested.svelte';
+</script>
+
+<Nested things={[1, 2]}>
+	<div slot="foo" let:thing>
+		{@const props = { thing }}
+		<span>{props.thing}</span>
+	</div>
+</Nested>

From f023e8d7c803040e9b719fabaed88439c388e8f3 Mon Sep 17 00:00:00 2001
From: Karl Georgsen <dev@karlgeorgsen.com>
Date: Fri, 22 May 2026 15:46:25 +0200
Subject: [PATCH 030/222] chore: add tag name to
 a11y_click_events_have_key_events warning (#18272)

Ref: https://github.com/sveltejs/svelte/issues/15100

Adds the tag name to the `a11y_click_events_have_key_events` warning
given when a non-interactive element has a click handler but no keyboard
events.
This already happens in `a11y_no_static_element_interactions`, and
should probably happen in many more messages.
---
 .changeset/true-dancers-tell.md                  |  5 +++++
 .../98-reference/.generated/compile-warnings.md  |  2 +-
 .../svelte/messages/compile-warnings/a11y.md     |  2 +-
 .../2-analyze/visitors/shared/a11y/index.js      |  2 +-
 packages/svelte/src/compiler/warnings.js         |  7 ++++---
 .../warnings.json                                | 16 ++++++++--------
 .../validator/samples/slot-warning/warnings.json |  2 +-
 .../samples/slot-warning2/warnings.json          |  2 +-
 8 files changed, 22 insertions(+), 16 deletions(-)
 create mode 100644 .changeset/true-dancers-tell.md

diff --git a/.changeset/true-dancers-tell.md b/.changeset/true-dancers-tell.md
new file mode 100644
index 0000000000..bd50b2ddc9
--- /dev/null
+++ b/.changeset/true-dancers-tell.md
@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+chore: add tag name to `a11y_click_events_have_key_events` warning
diff --git a/documentation/docs/98-reference/.generated/compile-warnings.md b/documentation/docs/98-reference/.generated/compile-warnings.md
index 7dfbe75888..fb53c644cf 100644
--- a/documentation/docs/98-reference/.generated/compile-warnings.md
+++ b/documentation/docs/98-reference/.generated/compile-warnings.md
@@ -62,7 +62,7 @@ Enforce that `autofocus` is not used on elements. Autofocusing elements can caus
 ### a11y_click_events_have_key_events
 
 ```
-Visible, non-interactive elements with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type="button">` or `<a>` might be more appropriate
+Visible, non-interactive element `<%element%>` with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type="button">` or `<a>` might be more appropriate
 ```
 
 Enforce that visible, non-interactive elements with an `onclick` event are accompanied by a keyboard event handler.
diff --git a/packages/svelte/messages/compile-warnings/a11y.md b/packages/svelte/messages/compile-warnings/a11y.md
index bc34829ce9..1f48ef0dd5 100644
--- a/packages/svelte/messages/compile-warnings/a11y.md
+++ b/packages/svelte/messages/compile-warnings/a11y.md
@@ -49,7 +49,7 @@ Enforce that `autofocus` is not used on elements. Autofocusing elements can caus
 
 ## a11y_click_events_have_key_events
 
-> Visible, non-interactive elements with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type="button">` or `<a>` might be more appropriate
+> Visible, non-interactive element `<%element%>` with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type="button">` or `<a>` might be more appropriate
 
 Enforce that visible, non-interactive elements with an `onclick` event are accompanied by a keyboard event handler.
 
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/a11y/index.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/a11y/index.js
index be3af1e59f..a6e801cf5a 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/a11y/index.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/a11y/index.js
@@ -302,7 +302,7 @@ export function check_element(node, context) {
 			const has_key_event =
 				handlers.has('keydown') || handlers.has('keyup') || handlers.has('keypress');
 			if (!has_key_event) {
-				w.a11y_click_events_have_key_events(node);
+				w.a11y_click_events_have_key_events(node, node.name);
 			}
 		}
 	}
diff --git a/packages/svelte/src/compiler/warnings.js b/packages/svelte/src/compiler/warnings.js
index 089cb1e118..c7d660a617 100644
--- a/packages/svelte/src/compiler/warnings.js
+++ b/packages/svelte/src/compiler/warnings.js
@@ -166,11 +166,12 @@ export function a11y_autofocus(node) {
 }
 
 /**
- * Visible, non-interactive elements with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type="button">` or `<a>` might be more appropriate
+ * Visible, non-interactive element `<%element%>` with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type="button">` or `<a>` might be more appropriate
  * @param {null | NodeLike} node
+ * @param {string} element
  */
-export function a11y_click_events_have_key_events(node) {
-	w(node, 'a11y_click_events_have_key_events', `Visible, non-interactive elements with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as \`<button type="button">\` or \`<a>\` might be more appropriate\nhttps://svelte.dev/e/a11y_click_events_have_key_events`);
+export function a11y_click_events_have_key_events(node, element) {
+	w(node, 'a11y_click_events_have_key_events', `Visible, non-interactive element \`<${element}>\` with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as \`<button type="button">\` or \`<a>\` might be more appropriate\nhttps://svelte.dev/e/a11y_click_events_have_key_events`);
 }
 
 /**
diff --git a/packages/svelte/tests/validator/samples/a11y-click-events-have-key-events/warnings.json b/packages/svelte/tests/validator/samples/a11y-click-events-have-key-events/warnings.json
index 0a759da957..a0d033ab16 100644
--- a/packages/svelte/tests/validator/samples/a11y-click-events-have-key-events/warnings.json
+++ b/packages/svelte/tests/validator/samples/a11y-click-events-have-key-events/warnings.json
@@ -1,7 +1,7 @@
 [
 	{
 		"code": "a11y_click_events_have_key_events",
-		"message": "Visible, non-interactive elements with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
+		"message": "Visible, non-interactive element `<div>` with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
 		"start": {
 			"line": 13,
 			"column": 0
@@ -13,7 +13,7 @@
 	},
 	{
 		"code": "a11y_click_events_have_key_events",
-		"message": "Visible, non-interactive elements with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
+		"message": "Visible, non-interactive element `<div>` with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
 		"start": {
 			"line": 15,
 			"column": 0
@@ -25,7 +25,7 @@
 	},
 	{
 		"code": "a11y_click_events_have_key_events",
-		"message": "Visible, non-interactive elements with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
+		"message": "Visible, non-interactive element `<section>` with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
 		"start": {
 			"line": 18,
 			"column": 0
@@ -37,7 +37,7 @@
 	},
 	{
 		"code": "a11y_click_events_have_key_events",
-		"message": "Visible, non-interactive elements with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
+		"message": "Visible, non-interactive element `<main>` with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
 		"start": {
 			"line": 20,
 			"column": 0
@@ -49,7 +49,7 @@
 	},
 	{
 		"code": "a11y_click_events_have_key_events",
-		"message": "Visible, non-interactive elements with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
+		"message": "Visible, non-interactive element `<article>` with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
 		"start": {
 			"line": 22,
 			"column": 0
@@ -61,7 +61,7 @@
 	},
 	{
 		"code": "a11y_click_events_have_key_events",
-		"message": "Visible, non-interactive elements with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
+		"message": "Visible, non-interactive element `<header>` with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
 		"start": {
 			"line": 24,
 			"column": 0
@@ -73,7 +73,7 @@
 	},
 	{
 		"code": "a11y_click_events_have_key_events",
-		"message": "Visible, non-interactive elements with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
+		"message": "Visible, non-interactive element `<footer>` with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
 		"start": {
 			"line": 26,
 			"column": 0
@@ -85,7 +85,7 @@
 	},
 	{
 		"code": "a11y_click_events_have_key_events",
-		"message": "Visible, non-interactive elements with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
+		"message": "Visible, non-interactive element `<footer>` with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
 		"start": {
 			"line": 28,
 			"column": 0
diff --git a/packages/svelte/tests/validator/samples/slot-warning/warnings.json b/packages/svelte/tests/validator/samples/slot-warning/warnings.json
index c146a7d716..e3cf5a8904 100644
--- a/packages/svelte/tests/validator/samples/slot-warning/warnings.json
+++ b/packages/svelte/tests/validator/samples/slot-warning/warnings.json
@@ -1,7 +1,7 @@
 [
 	{
 		"code": "a11y_click_events_have_key_events",
-		"message": "Visible, non-interactive elements with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
+		"message": "Visible, non-interactive element `<div>` with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
 		"start": {
 			"column": 1,
 			"line": 7
diff --git a/packages/svelte/tests/validator/samples/slot-warning2/warnings.json b/packages/svelte/tests/validator/samples/slot-warning2/warnings.json
index b8b9876ebb..95f6ff0733 100644
--- a/packages/svelte/tests/validator/samples/slot-warning2/warnings.json
+++ b/packages/svelte/tests/validator/samples/slot-warning2/warnings.json
@@ -1,7 +1,7 @@
 [
 	{
 		"code": "a11y_click_events_have_key_events",
-		"message": "Visible, non-interactive elements with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
+		"message": "Visible, non-interactive element `<div>` with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type=\"button\">` or `<a>` might be more appropriate",
 		"start": {
 			"column": 1,
 			"line": 8

From fe9ab936b6aa646ef87c636ec8803d42f8b7bb1d Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Fri, 22 May 2026 17:48:31 +0200
Subject: [PATCH 031/222] fix: allow `$derived(await ...)` in disconnected
 effect roots (#18273)

If `$effect.root` is created outside the component tree, the boundary
property is null

Fixes #18188
---
 .changeset/fine-corners-lay.md                        |  5 +++++
 .../svelte/src/internal/client/reactivity/deriveds.js |  5 ++++-
 .../async-async-disconnected-effect-root/_config.js   |  9 +++++++++
 .../async-async-disconnected-effect-root/main.svelte  | 11 +++++++++++
 4 files changed, 29 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/fine-corners-lay.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-async-disconnected-effect-root/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-async-disconnected-effect-root/main.svelte

diff --git a/.changeset/fine-corners-lay.md b/.changeset/fine-corners-lay.md
new file mode 100644
index 0000000000..badbc6f81f
--- /dev/null
+++ b/.changeset/fine-corners-lay.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: allow `$derived(await ...)` in disconnected effect roots
diff --git a/packages/svelte/src/internal/client/reactivity/deriveds.js b/packages/svelte/src/internal/client/reactivity/deriveds.js
index 8d240bca31..7ea6de6306 100644
--- a/packages/svelte/src/internal/client/reactivity/deriveds.js
+++ b/packages/svelte/src/internal/client/reactivity/deriveds.js
@@ -187,7 +187,10 @@ export function async_derived(fn, label, location) {
 				var decrement_pending = increment_pending();
 			}
 
-			if (/** @type {Boundary} */ (parent.b).is_rendered()) {
+			if (
+				// boundary can be null if the async derived is inside an $effect.root not connected to the component render tree
+				parent.b?.is_rendered()
+			) {
 				batch.async_deriveds.get(effect)?.reject(OBSOLETE);
 			} else {
 				// While the boundary is still showing pending, a new run supersedes all older in-flight runs
diff --git a/packages/svelte/tests/runtime-runes/samples/async-async-disconnected-effect-root/_config.js b/packages/svelte/tests/runtime-runes/samples/async-async-disconnected-effect-root/_config.js
new file mode 100644
index 0000000000..ecf048abc3
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-async-disconnected-effect-root/_config.js
@@ -0,0 +1,9 @@
+import { test } from '../../test';
+
+export default test({
+	// Test that an async derived inside an $effect.root not connected to the component tree still works
+	async test({ assert, logs }) {
+		await new Promise((resolve) => setTimeout(resolve, 10));
+		assert.deepEqual(logs, [1]);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-async-disconnected-effect-root/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-async-disconnected-effect-root/main.svelte
new file mode 100644
index 0000000000..37c8919023
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-async-disconnected-effect-root/main.svelte
@@ -0,0 +1,11 @@
+<script>
+	setTimeout(() => {
+		$effect.root(() => {
+			async function fn() {
+				const value = $derived(await 1);
+				return { get value() { return value } };
+			}
+			fn().then(r => console.log(r.value));
+		})
+	})
+</script>

From e6110d31c5be64f4964cda40abe1dd0bedd49eb9 Mon Sep 17 00:00:00 2001
From: Mathias Picker <48158184+MathiasWP@users.noreply.github.com>
Date: Tue, 26 May 2026 14:45:29 +0200
Subject: [PATCH 032/222] perf: use Set instead of Array for constant lookups
 in utils.js (#18250)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Several constant lookup tables in `utils.js` were arrays searched with
`Array.prototype.includes`, which is O(n). They're queried often — per
attribute during attribute setup and SSR, per event during event
delegation, and per identifier during compilation. Switching them to
`Set` makes each lookup O(1) without changing any public behaviour.
---
 .changeset/swift-sets-lookup.md |   5 ++
 packages/svelte/src/utils.js    | 128 ++++++++++++++++----------------
 2 files changed, 69 insertions(+), 64 deletions(-)
 create mode 100644 .changeset/swift-sets-lookup.md

diff --git a/.changeset/swift-sets-lookup.md b/.changeset/swift-sets-lookup.md
new file mode 100644
index 0000000000..af6f774ca4
--- /dev/null
+++ b/.changeset/swift-sets-lookup.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+perf: use `Set` for static attribute and event lookups
diff --git a/packages/svelte/src/utils.js b/packages/svelte/src/utils.js
index 54757a6f13..fa8ccdfe12 100644
--- a/packages/svelte/src/utils.js
+++ b/packages/svelte/src/utils.js
@@ -13,7 +13,7 @@ export function hash(str) {
 	return (hash >>> 0).toString(36);
 }
 
-const VOID_ELEMENT_NAMES = [
+const VOID_ELEMENT_NAMES = new Set([
 	'area',
 	'base',
 	'br',
@@ -30,17 +30,17 @@ const VOID_ELEMENT_NAMES = [
 	'source',
 	'track',
 	'wbr'
-];
+]);
 
 /**
  * Returns `true` if `name` is of a void element
  * @param {string} name
  */
 export function is_void(name) {
-	return VOID_ELEMENT_NAMES.includes(name) || name.toLowerCase() === '!doctype';
+	return VOID_ELEMENT_NAMES.has(name) || name.toLowerCase() === '!doctype';
 }
 
-const RESERVED_WORDS = [
+const RESERVED_WORDS = new Set([
 	'arguments',
 	'await',
 	'break',
@@ -89,14 +89,14 @@ const RESERVED_WORDS = [
 	'while',
 	'with',
 	'yield'
-];
+]);
 
 /**
  * Returns `true` if `word` is a reserved JavaScript keyword
  * @param {string} word
  */
 export function is_reserved(word) {
-	return RESERVED_WORDS.includes(word);
+	return RESERVED_WORDS.has(word);
 }
 
 /**
@@ -106,8 +106,8 @@ export function is_capture_event(name) {
 	return name.endsWith('capture') && name !== 'gotpointercapture' && name !== 'lostpointercapture';
 }
 
-/** List of Element events that will be delegated */
-const DELEGATED_EVENTS = [
+/** Set of Element events that will be delegated */
+const DELEGATED_EVENTS = new Set([
 	'beforeinput',
 	'click',
 	'change',
@@ -131,20 +131,20 @@ const DELEGATED_EVENTS = [
 	'touchend',
 	'touchmove',
 	'touchstart'
-];
+]);
 
 /**
  * Returns `true` if `event_name` is a delegated event
  * @param {string} event_name
  */
 export function can_delegate_event(event_name) {
-	return DELEGATED_EVENTS.includes(event_name);
+	return DELEGATED_EVENTS.has(event_name);
 }
 
 /**
  * Attributes that are boolean, i.e. they are present or not present.
  */
-const DOM_BOOLEAN_ATTRIBUTES = [
+const DOM_BOOLEAN_ATTRIBUTES = new Set([
 	'allowfullscreen',
 	'async',
 	'autofocus',
@@ -173,14 +173,14 @@ const DOM_BOOLEAN_ATTRIBUTES = [
 	'defer',
 	'disablepictureinpicture',
 	'disableremoteplayback'
-];
+]);
 
 /**
  * Returns `true` if `name` is a boolean attribute
  * @param {string} name
  */
 export function is_boolean_attribute(name) {
-	return DOM_BOOLEAN_ATTRIBUTES.includes(name);
+	return DOM_BOOLEAN_ATTRIBUTES.has(name);
 }
 
 /**
@@ -213,7 +213,7 @@ export function normalize_attribute(name) {
 	return ATTRIBUTE_ALIASES[name] ?? name;
 }
 
-const DOM_PROPERTIES = [
+const DOM_PROPERTIES = new Set([
 	...DOM_BOOLEAN_ATTRIBUTES,
 	'formNoValidate',
 	'isMap',
@@ -229,16 +229,16 @@ const DOM_PROPERTIES = [
 	'allowFullscreen',
 	'disablePictureInPicture',
 	'disableRemotePlayback'
-];
+]);
 
 /**
  * @param {string} name
  */
 export function is_dom_property(name) {
-	return DOM_PROPERTIES.includes(name);
+	return DOM_PROPERTIES.has(name);
 }
 
-const NON_STATIC_PROPERTIES = ['autofocus', 'muted', 'defaultValue', 'defaultChecked'];
+const NON_STATIC_PROPERTIES = new Set(['autofocus', 'muted', 'defaultValue', 'defaultChecked']);
 
 /**
  * Returns `true` if the given attribute cannot be set through the template
@@ -246,7 +246,7 @@ const NON_STATIC_PROPERTIES = ['autofocus', 'muted', 'defaultValue', 'defaultChe
  * @param {string} name
  */
 export function cannot_be_set_statically(name) {
-	return NON_STATIC_PROPERTIES.includes(name);
+	return NON_STATIC_PROPERTIES.has(name);
 }
 
 /**
@@ -258,24 +258,24 @@ export function cannot_be_set_statically(name) {
  * - they apply to mobile which is generally less performant
  * we're marking them as passive by default for other elements, too.
  */
-const PASSIVE_EVENTS = ['touchstart', 'touchmove'];
+const PASSIVE_EVENTS = new Set(['touchstart', 'touchmove']);
 
 /**
  * Returns `true` if `name` is a passive event
  * @param {string} name
  */
 export function is_passive_event(name) {
-	return PASSIVE_EVENTS.includes(name);
+	return PASSIVE_EVENTS.has(name);
 }
 
-const CONTENT_EDITABLE_BINDINGS = ['textContent', 'innerHTML', 'innerText'];
+const CONTENT_EDITABLE_BINDINGS = new Set(['textContent', 'innerHTML', 'innerText']);
 
 /** @param {string} name */
 export function is_content_editable_binding(name) {
-	return CONTENT_EDITABLE_BINDINGS.includes(name);
+	return CONTENT_EDITABLE_BINDINGS.has(name);
 }
 
-const LOAD_ERROR_ELEMENTS = [
+const LOAD_ERROR_ELEMENTS = new Set([
 	'body',
 	'embed',
 	'iframe',
@@ -285,17 +285,17 @@ const LOAD_ERROR_ELEMENTS = [
 	'script',
 	'style',
 	'track'
-];
+]);
 
 /**
  * Returns `true` if the element emits `load` and `error` events
  * @param {string} name
  */
 export function is_load_error_element(name) {
-	return LOAD_ERROR_ELEMENTS.includes(name);
+	return LOAD_ERROR_ELEMENTS.has(name);
 }
 
-const SVG_ELEMENTS = [
+const SVG_ELEMENTS = new Set([
 	'altGlyph',
 	'altGlyphDef',
 	'altGlyphItem',
@@ -382,14 +382,14 @@ const SVG_ELEMENTS = [
 	'use',
 	'view',
 	'vkern'
-];
+]);
 
 /** @param {string} name */
 export function is_svg(name) {
-	return SVG_ELEMENTS.includes(name);
+	return SVG_ELEMENTS.has(name);
 }
 
-const MATHML_ELEMENTS = [
+const MATHML_ELEMENTS = new Set([
 	'annotation',
 	'annotation-xml',
 	'maction',
@@ -420,64 +420,64 @@ const MATHML_ELEMENTS = [
 	'munder',
 	'munderover',
 	'semantics'
-];
+]);
 
 /** @param {string} name */
 export function is_mathml(name) {
-	return MATHML_ELEMENTS.includes(name);
+	return MATHML_ELEMENTS.has(name);
 }
 
-const STATE_CREATION_RUNES = /** @type {const} */ ([
-	'$state',
-	'$state.raw',
-	'$derived',
-	'$derived.by'
-]);
-
-const RUNES = /** @type {const} */ ([
-	...STATE_CREATION_RUNES,
-	'$state.eager',
-	'$state.snapshot',
-	'$props',
-	'$props.id',
-	'$bindable',
-	'$effect',
-	'$effect.pre',
-	'$effect.tracking',
-	'$effect.root',
-	'$effect.pending',
-	'$inspect',
-	'$inspect().with',
-	'$inspect.trace',
-	'$host'
-]);
-
-/** @typedef {typeof RUNES[number]} RuneName */
+const STATE_CREATION_RUNES = new Set(
+	/** @type {const} */ (['$state', '$state.raw', '$derived', '$derived.by'])
+);
+
+const RUNES = new Set(
+	/** @type {const} */ ([
+		...STATE_CREATION_RUNES,
+		'$state.eager',
+		'$state.snapshot',
+		'$props',
+		'$props.id',
+		'$bindable',
+		'$effect',
+		'$effect.pre',
+		'$effect.tracking',
+		'$effect.root',
+		'$effect.pending',
+		'$inspect',
+		'$inspect().with',
+		'$inspect.trace',
+		'$host'
+	])
+);
+
+/** @typedef {typeof RUNES extends Set<infer T> ? T : never} RuneName */
+/** @typedef {typeof STATE_CREATION_RUNES extends Set<infer T> ? T : never} StateCreationRuneName */
 
 /**
  * @param {string} name
  * @returns {name is RuneName}
  */
 export function is_rune(name) {
-	return RUNES.includes(/** @type {RuneName} */ (name));
+	return RUNES.has(/** @type {RuneName} */ (name));
 }
 
-/** @typedef {typeof STATE_CREATION_RUNES[number]} StateCreationRuneName */
-
 /**
  * @param {string} name
  * @returns {name is StateCreationRuneName}
  */
 export function is_state_creation_rune(name) {
-	return STATE_CREATION_RUNES.includes(/** @type {StateCreationRuneName} */ (name));
+	return STATE_CREATION_RUNES.has(/** @type {StateCreationRuneName} */ (name));
 }
 
-/** List of elements that require raw contents and should not have SSR comments put in them */
-const RAW_TEXT_ELEMENTS = /** @type {const} */ (['textarea', 'script', 'style', 'title']);
+/** Elements that require raw contents and should not have SSR comments put in them */
+const RAW_TEXT_ELEMENTS = new Set(/** @type {const} */ (['textarea', 'script', 'style', 'title']));
+
+/** @typedef {typeof RAW_TEXT_ELEMENTS extends Set<infer T> ? T : never} RawTextElement */
 
 /** @param {string} name */
 export function is_raw_text_element(name) {
-	return RAW_TEXT_ELEMENTS.includes(/** @type {typeof RAW_TEXT_ELEMENTS[number]} */ (name));
+	return RAW_TEXT_ELEMENTS.has(/** @type {RawTextElement} */ (name));
 }
 
 // Matches valid HTML/SVG/MathML element names and custom element names.

From 871e590c594c2c4ec42ad9fa160bff7f3e445784 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Tue, 26 May 2026 18:14:35 +0200
Subject: [PATCH 033/222] fix: settle discarded batch (#18290)

Without this the promise would never resolve
---
 .changeset/neat-groups-grin.md                |  5 +++
 .../src/internal/client/reactivity/batch.js   |  1 +
 .../samples/async-settled-discard/_config.js  | 37 +++++++++++++++++++
 .../samples/async-settled-discard/main.svelte | 22 +++++++++++
 4 files changed, 65 insertions(+)
 create mode 100644 .changeset/neat-groups-grin.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-settled-discard/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-settled-discard/main.svelte

diff --git a/.changeset/neat-groups-grin.md b/.changeset/neat-groups-grin.md
new file mode 100644
index 0000000000..1d615216f0
--- /dev/null
+++ b/.changeset/neat-groups-grin.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: settle discarded batch
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 82c97cf95c..08e8cf24c4 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -633,6 +633,7 @@ export class Batch {
 		this.#fork_commit_callbacks.clear();
 
 		this.#unlink();
+		this.#deferred?.resolve();
 	}
 
 	/**
diff --git a/packages/svelte/tests/runtime-runes/samples/async-settled-discard/_config.js b/packages/svelte/tests/runtime-runes/samples/async-settled-discard/_config.js
new file mode 100644
index 0000000000..29ed72d90a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-settled-discard/_config.js
@@ -0,0 +1,37 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target, logs }) {
+		await tick();
+		const [increment, pop] = target.querySelectorAll('button');
+
+		increment.click();
+		await tick();
+		increment.click();
+		await tick();
+		pop.click();
+		await tick();
+		assert.deepEqual(logs, ['settled 2', 'settled 2']);
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				2
+				<button>increment</button>
+				<button>pop</button>
+			`
+		);
+
+		pop.click();
+		await tick();
+		assert.deepEqual(logs, ['settled 2', 'settled 2']);
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				2
+				<button>increment</button>
+				<button>pop</button>
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-settled-discard/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-settled-discard/main.svelte
new file mode 100644
index 0000000000..c3675f8add
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-settled-discard/main.svelte
@@ -0,0 +1,22 @@
+<script>
+	import { settled } from "svelte";
+
+	let count = $state(0);
+	let queued = [];
+
+	function push(v) {
+		if (!v) return v;
+
+		return new Promise((resolve) => {
+			queued.push(() => resolve(v));
+		});
+	}
+</script>
+
+{await push(count)}
+<button onclick={async () => {
+	count++;
+	await settled();
+	console.log('settled ' + count);
+}}>increment</button>
+<button onclick={() => queued.pop()?.()}>pop</button>

From 60eaa92b0bdd576d8ad791a8ed7ad56bcb1575db Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Tue, 26 May 2026 18:16:27 +0200
Subject: [PATCH 034/222] fix: resume outro-ed branches if they were kept
 around (#18291)

If a branch is removed from the visible dom, it may be kept around
because a subsequent batch will intro it again. If we don't resume the
effects it will stay inert and therefore not react to updates anymore
---
 .changeset/sad-shoes-help.md                  |  5 ++
 .../internal/client/dom/blocks/branches.js    |  2 +
 .../samples/async-branch-reintro/_config.js   | 58 +++++++++++++++++++
 .../samples/async-branch-reintro/main.svelte  | 23 ++++++++
 4 files changed, 88 insertions(+)
 create mode 100644 .changeset/sad-shoes-help.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-branch-reintro/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-branch-reintro/main.svelte

diff --git a/.changeset/sad-shoes-help.md b/.changeset/sad-shoes-help.md
new file mode 100644
index 0000000000..76db87ba95
--- /dev/null
+++ b/.changeset/sad-shoes-help.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: resume outro-ed branches if they were kept around
diff --git a/packages/svelte/src/internal/client/dom/blocks/branches.js b/packages/svelte/src/internal/client/dom/blocks/branches.js
index 33c34f58bb..141b914537 100644
--- a/packages/svelte/src/internal/client/dom/blocks/branches.js
+++ b/packages/svelte/src/internal/client/dom/blocks/branches.js
@@ -90,6 +90,8 @@ export class BranchManager {
 			var offscreen = this.#offscreen.get(key);
 
 			if (offscreen) {
+				// effect could have been outro'ed before through a prior batch — resume if necessary
+				resume_effect(offscreen.effect);
 				this.#onscreen.set(key, offscreen.effect);
 				this.#offscreen.delete(key);
 
diff --git a/packages/svelte/tests/runtime-runes/samples/async-branch-reintro/_config.js b/packages/svelte/tests/runtime-runes/samples/async-branch-reintro/_config.js
new file mode 100644
index 0000000000..928db008e6
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-branch-reintro/_config.js
@@ -0,0 +1,58 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		await tick();
+		const [inc_count, inc_both, shift] = target.querySelectorAll('button');
+
+		inc_both.click();
+		await tick();
+		inc_count.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+			<button>increment count</button>
+			<button>increment both</button>
+			<button>shift</button>
+			0
+			0
+			<button>0</button>
+		`
+		);
+
+		shift.click();
+		await tick();
+		shift.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>increment count</button>
+				<button>increment both</button>
+				<button>shift</button>
+				1
+				2
+				<button>1</button>
+			`
+		);
+
+		const button = /** @type {HTMLButtonElement} */ (target.querySelector('button:last-child'));
+		button.click();
+		await tick();
+		shift.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>increment count</button>
+				<button>increment both</button>
+				<button>shift</button>
+				2
+				2
+				<button>2</button>
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-branch-reintro/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-branch-reintro/main.svelte
new file mode 100644
index 0000000000..92b7669fa9
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-branch-reintro/main.svelte
@@ -0,0 +1,23 @@
+<script>
+	let count = $state(0);
+	let other = $state(0);
+	let queued = [];
+
+	function push(v) {
+		if (!v) return v;
+
+		return new Promise((resolve) => {
+			queued.push(() => resolve(v));
+		});
+	}
+</script>
+
+<button onclick={() => count++}>increment count</button>
+<button onclick={() => {count++;other++}}>increment both</button>
+<button onclick={() => queued.shift()?.()}>shift</button>
+
+{await push(other)}
+{#if count % 2 === 0}
+	{await push(count)}
+	<button onclick={() => other++}>{other}</button>
+{/if}

From d2c7fa34945272aae500f90536aa9fdffdc35e7e Mon Sep 17 00:00:00 2001
From: RonGamzu <37371774+RonGamzu@users.noreply.github.com>
Date: Tue, 26 May 2026 19:21:51 +0300
Subject: [PATCH 035/222] fix: use consistent spelling in
 script_unknown_attribute warning (#18281)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

## Summary

The `script_unknown_attribute` warning message used American English
(`Unrecognized`) while every other user-facing error/warning in the
compiler uses British English (`Unrecognised`):

- `options_unrecognised` error: `Unrecognised compiler option…`
- `unknown_code` warning: `is not a recognised code`

This change updates `script_unknown_attribute` to match, then
regenerates `warnings.js` and the reference documentation from the
source message file via `node scripts/process-messages`.

## Test plan
- Spelling change is isolated to the `script_unknown_attribute` warning
message
- `warnings.js` and generated docs were updated by running `node
scripts/process-messages`
- All three occurrences (source, generated JS, generated docs) are
consistent
---
 .../docs/98-reference/.generated/compile-warnings.md          | 2 +-
 packages/svelte/messages/compile-warnings/template.md         | 2 +-
 packages/svelte/src/compiler/warnings.js                      | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/documentation/docs/98-reference/.generated/compile-warnings.md b/documentation/docs/98-reference/.generated/compile-warnings.md
index fb53c644cf..f372a010a5 100644
--- a/documentation/docs/98-reference/.generated/compile-warnings.md
+++ b/documentation/docs/98-reference/.generated/compile-warnings.md
@@ -842,7 +842,7 @@ Reassignments of module-level declarations will not cause reactive statements to
 ### script_unknown_attribute
 
 ```
-Unrecognized attribute — should be one of `generics`, `lang` or `module`. If this exists for a preprocessor, ensure that the preprocessor removes it
+Unrecognised attribute — should be one of `generics`, `lang` or `module`. If this exists for a preprocessor, ensure that the preprocessor removes it
 ```
 
 ### slot_element_deprecated
diff --git a/packages/svelte/messages/compile-warnings/template.md b/packages/svelte/messages/compile-warnings/template.md
index 3650e07b47..f1e32a6d18 100644
--- a/packages/svelte/messages/compile-warnings/template.md
+++ b/packages/svelte/messages/compile-warnings/template.md
@@ -107,7 +107,7 @@ This code will work when the component is rendered on the client (which is why t
 
 ## script_unknown_attribute
 
-> Unrecognized attribute — should be one of `generics`, `lang` or `module`. If this exists for a preprocessor, ensure that the preprocessor removes it
+> Unrecognised attribute — should be one of `generics`, `lang` or `module`. If this exists for a preprocessor, ensure that the preprocessor removes it
 
 ## slot_element_deprecated
 
diff --git a/packages/svelte/src/compiler/warnings.js b/packages/svelte/src/compiler/warnings.js
index c7d660a617..98f407671d 100644
--- a/packages/svelte/src/compiler/warnings.js
+++ b/packages/svelte/src/compiler/warnings.js
@@ -804,11 +804,11 @@ export function script_context_deprecated(node) {
 }
 
 /**
- * Unrecognized attribute — should be one of `generics`, `lang` or `module`. If this exists for a preprocessor, ensure that the preprocessor removes it
+ * Unrecognised attribute — should be one of `generics`, `lang` or `module`. If this exists for a preprocessor, ensure that the preprocessor removes it
  * @param {null | NodeLike} node
  */
 export function script_unknown_attribute(node) {
-	w(node, 'script_unknown_attribute', `Unrecognized attribute — should be one of \`generics\`, \`lang\` or \`module\`. If this exists for a preprocessor, ensure that the preprocessor removes it\nhttps://svelte.dev/e/script_unknown_attribute`);
+	w(node, 'script_unknown_attribute', `Unrecognised attribute — should be one of \`generics\`, \`lang\` or \`module\`. If this exists for a preprocessor, ensure that the preprocessor removes it\nhttps://svelte.dev/e/script_unknown_attribute`);
 }
 
 /**

From c9f7298270d4e913a2bb6826f5f193d95bf34cd6 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Tue, 26 May 2026 12:29:40 -0400
Subject: [PATCH 036/222] chore: fix spelling in test (#18292)

ugh i forgot to approve workflows in slop PR #18281 and now tests are
failing
---
 .../samples/script-invalid-spread-attribute/warnings.json       | 2 +-
 .../validator/samples/script-unknown-attribute/warnings.json    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/svelte/tests/validator/samples/script-invalid-spread-attribute/warnings.json b/packages/svelte/tests/validator/samples/script-invalid-spread-attribute/warnings.json
index c6748f711d..35045313ba 100644
--- a/packages/svelte/tests/validator/samples/script-invalid-spread-attribute/warnings.json
+++ b/packages/svelte/tests/validator/samples/script-invalid-spread-attribute/warnings.json
@@ -1,7 +1,7 @@
 [
 	{
 		"code": "script_unknown_attribute",
-		"message": "Unrecognized attribute — should be one of `generics`, `lang` or `module`. If this exists for a preprocessor, ensure that the preprocessor removes it",
+		"message": "Unrecognised attribute — should be one of `generics`, `lang` or `module`. If this exists for a preprocessor, ensure that the preprocessor removes it",
 		"start": {
 			"column": 8,
 			"line": 1
diff --git a/packages/svelte/tests/validator/samples/script-unknown-attribute/warnings.json b/packages/svelte/tests/validator/samples/script-unknown-attribute/warnings.json
index fdcad269a6..0d41c2dc12 100644
--- a/packages/svelte/tests/validator/samples/script-unknown-attribute/warnings.json
+++ b/packages/svelte/tests/validator/samples/script-unknown-attribute/warnings.json
@@ -1,7 +1,7 @@
 [
 	{
 		"code": "script_unknown_attribute",
-		"message": "Unrecognized attribute — should be one of `generics`, `lang` or `module`. If this exists for a preprocessor, ensure that the preprocessor removes it",
+		"message": "Unrecognised attribute — should be one of `generics`, `lang` or `module`. If this exists for a preprocessor, ensure that the preprocessor removes it",
 		"start": {
 			"column": 8,
 			"line": 1

From 070a0c4f7708ae0caa209ff762d98c0f117e6adb Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Tue, 26 May 2026 15:44:56 -0400
Subject: [PATCH 037/222] Revert "perf: use Set instead of Array for constant
 lookups in utils.js" (#18294)

Reverts sveltejs/svelte#18250
---
 .changeset/swift-sets-lookup.md |   5 --
 packages/svelte/src/utils.js    | 128 ++++++++++++++++----------------
 2 files changed, 64 insertions(+), 69 deletions(-)
 delete mode 100644 .changeset/swift-sets-lookup.md

diff --git a/.changeset/swift-sets-lookup.md b/.changeset/swift-sets-lookup.md
deleted file mode 100644
index af6f774ca4..0000000000
--- a/.changeset/swift-sets-lookup.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-perf: use `Set` for static attribute and event lookups
diff --git a/packages/svelte/src/utils.js b/packages/svelte/src/utils.js
index fa8ccdfe12..54757a6f13 100644
--- a/packages/svelte/src/utils.js
+++ b/packages/svelte/src/utils.js
@@ -13,7 +13,7 @@ export function hash(str) {
 	return (hash >>> 0).toString(36);
 }
 
-const VOID_ELEMENT_NAMES = new Set([
+const VOID_ELEMENT_NAMES = [
 	'area',
 	'base',
 	'br',
@@ -30,17 +30,17 @@ const VOID_ELEMENT_NAMES = new Set([
 	'source',
 	'track',
 	'wbr'
-]);
+];
 
 /**
  * Returns `true` if `name` is of a void element
  * @param {string} name
  */
 export function is_void(name) {
-	return VOID_ELEMENT_NAMES.has(name) || name.toLowerCase() === '!doctype';
+	return VOID_ELEMENT_NAMES.includes(name) || name.toLowerCase() === '!doctype';
 }
 
-const RESERVED_WORDS = new Set([
+const RESERVED_WORDS = [
 	'arguments',
 	'await',
 	'break',
@@ -89,14 +89,14 @@ const RESERVED_WORDS = new Set([
 	'while',
 	'with',
 	'yield'
-]);
+];
 
 /**
  * Returns `true` if `word` is a reserved JavaScript keyword
  * @param {string} word
  */
 export function is_reserved(word) {
-	return RESERVED_WORDS.has(word);
+	return RESERVED_WORDS.includes(word);
 }
 
 /**
@@ -106,8 +106,8 @@ export function is_capture_event(name) {
 	return name.endsWith('capture') && name !== 'gotpointercapture' && name !== 'lostpointercapture';
 }
 
-/** Set of Element events that will be delegated */
-const DELEGATED_EVENTS = new Set([
+/** List of Element events that will be delegated */
+const DELEGATED_EVENTS = [
 	'beforeinput',
 	'click',
 	'change',
@@ -131,20 +131,20 @@ const DELEGATED_EVENTS = new Set([
 	'touchend',
 	'touchmove',
 	'touchstart'
-]);
+];
 
 /**
  * Returns `true` if `event_name` is a delegated event
  * @param {string} event_name
  */
 export function can_delegate_event(event_name) {
-	return DELEGATED_EVENTS.has(event_name);
+	return DELEGATED_EVENTS.includes(event_name);
 }
 
 /**
  * Attributes that are boolean, i.e. they are present or not present.
  */
-const DOM_BOOLEAN_ATTRIBUTES = new Set([
+const DOM_BOOLEAN_ATTRIBUTES = [
 	'allowfullscreen',
 	'async',
 	'autofocus',
@@ -173,14 +173,14 @@ const DOM_BOOLEAN_ATTRIBUTES = new Set([
 	'defer',
 	'disablepictureinpicture',
 	'disableremoteplayback'
-]);
+];
 
 /**
  * Returns `true` if `name` is a boolean attribute
  * @param {string} name
  */
 export function is_boolean_attribute(name) {
-	return DOM_BOOLEAN_ATTRIBUTES.has(name);
+	return DOM_BOOLEAN_ATTRIBUTES.includes(name);
 }
 
 /**
@@ -213,7 +213,7 @@ export function normalize_attribute(name) {
 	return ATTRIBUTE_ALIASES[name] ?? name;
 }
 
-const DOM_PROPERTIES = new Set([
+const DOM_PROPERTIES = [
 	...DOM_BOOLEAN_ATTRIBUTES,
 	'formNoValidate',
 	'isMap',
@@ -229,16 +229,16 @@ const DOM_PROPERTIES = new Set([
 	'allowFullscreen',
 	'disablePictureInPicture',
 	'disableRemotePlayback'
-]);
+];
 
 /**
  * @param {string} name
  */
 export function is_dom_property(name) {
-	return DOM_PROPERTIES.has(name);
+	return DOM_PROPERTIES.includes(name);
 }
 
-const NON_STATIC_PROPERTIES = new Set(['autofocus', 'muted', 'defaultValue', 'defaultChecked']);
+const NON_STATIC_PROPERTIES = ['autofocus', 'muted', 'defaultValue', 'defaultChecked'];
 
 /**
  * Returns `true` if the given attribute cannot be set through the template
@@ -246,7 +246,7 @@ const NON_STATIC_PROPERTIES = new Set(['autofocus', 'muted', 'defaultValue', 'de
  * @param {string} name
  */
 export function cannot_be_set_statically(name) {
-	return NON_STATIC_PROPERTIES.has(name);
+	return NON_STATIC_PROPERTIES.includes(name);
 }
 
 /**
@@ -258,24 +258,24 @@ export function cannot_be_set_statically(name) {
  * - they apply to mobile which is generally less performant
  * we're marking them as passive by default for other elements, too.
  */
-const PASSIVE_EVENTS = new Set(['touchstart', 'touchmove']);
+const PASSIVE_EVENTS = ['touchstart', 'touchmove'];
 
 /**
  * Returns `true` if `name` is a passive event
  * @param {string} name
  */
 export function is_passive_event(name) {
-	return PASSIVE_EVENTS.has(name);
+	return PASSIVE_EVENTS.includes(name);
 }
 
-const CONTENT_EDITABLE_BINDINGS = new Set(['textContent', 'innerHTML', 'innerText']);
+const CONTENT_EDITABLE_BINDINGS = ['textContent', 'innerHTML', 'innerText'];
 
 /** @param {string} name */
 export function is_content_editable_binding(name) {
-	return CONTENT_EDITABLE_BINDINGS.has(name);
+	return CONTENT_EDITABLE_BINDINGS.includes(name);
 }
 
-const LOAD_ERROR_ELEMENTS = new Set([
+const LOAD_ERROR_ELEMENTS = [
 	'body',
 	'embed',
 	'iframe',
@@ -285,17 +285,17 @@ const LOAD_ERROR_ELEMENTS = new Set([
 	'script',
 	'style',
 	'track'
-]);
+];
 
 /**
  * Returns `true` if the element emits `load` and `error` events
  * @param {string} name
  */
 export function is_load_error_element(name) {
-	return LOAD_ERROR_ELEMENTS.has(name);
+	return LOAD_ERROR_ELEMENTS.includes(name);
 }
 
-const SVG_ELEMENTS = new Set([
+const SVG_ELEMENTS = [
 	'altGlyph',
 	'altGlyphDef',
 	'altGlyphItem',
@@ -382,14 +382,14 @@ const SVG_ELEMENTS = new Set([
 	'use',
 	'view',
 	'vkern'
-]);
+];
 
 /** @param {string} name */
 export function is_svg(name) {
-	return SVG_ELEMENTS.has(name);
+	return SVG_ELEMENTS.includes(name);
 }
 
-const MATHML_ELEMENTS = new Set([
+const MATHML_ELEMENTS = [
 	'annotation',
 	'annotation-xml',
 	'maction',
@@ -420,64 +420,64 @@ const MATHML_ELEMENTS = new Set([
 	'munder',
 	'munderover',
 	'semantics'
-]);
+];
 
 /** @param {string} name */
 export function is_mathml(name) {
-	return MATHML_ELEMENTS.has(name);
+	return MATHML_ELEMENTS.includes(name);
 }
 
-const STATE_CREATION_RUNES = new Set(
-	/** @type {const} */ (['$state', '$state.raw', '$derived', '$derived.by'])
-);
-
-const RUNES = new Set(
-	/** @type {const} */ ([
-		...STATE_CREATION_RUNES,
-		'$state.eager',
-		'$state.snapshot',
-		'$props',
-		'$props.id',
-		'$bindable',
-		'$effect',
-		'$effect.pre',
-		'$effect.tracking',
-		'$effect.root',
-		'$effect.pending',
-		'$inspect',
-		'$inspect().with',
-		'$inspect.trace',
-		'$host'
-	])
-);
-
-/** @typedef {typeof RUNES extends Set<infer T> ? T : never} RuneName */
-/** @typedef {typeof STATE_CREATION_RUNES extends Set<infer T> ? T : never} StateCreationRuneName */
+const STATE_CREATION_RUNES = /** @type {const} */ ([
+	'$state',
+	'$state.raw',
+	'$derived',
+	'$derived.by'
+]);
+
+const RUNES = /** @type {const} */ ([
+	...STATE_CREATION_RUNES,
+	'$state.eager',
+	'$state.snapshot',
+	'$props',
+	'$props.id',
+	'$bindable',
+	'$effect',
+	'$effect.pre',
+	'$effect.tracking',
+	'$effect.root',
+	'$effect.pending',
+	'$inspect',
+	'$inspect().with',
+	'$inspect.trace',
+	'$host'
+]);
+
+/** @typedef {typeof RUNES[number]} RuneName */
 
 /**
  * @param {string} name
  * @returns {name is RuneName}
  */
 export function is_rune(name) {
-	return RUNES.has(/** @type {RuneName} */ (name));
+	return RUNES.includes(/** @type {RuneName} */ (name));
 }
 
+/** @typedef {typeof STATE_CREATION_RUNES[number]} StateCreationRuneName */
+
 /**
  * @param {string} name
  * @returns {name is StateCreationRuneName}
  */
 export function is_state_creation_rune(name) {
-	return STATE_CREATION_RUNES.has(/** @type {StateCreationRuneName} */ (name));
+	return STATE_CREATION_RUNES.includes(/** @type {StateCreationRuneName} */ (name));
 }
 
-/** Elements that require raw contents and should not have SSR comments put in them */
-const RAW_TEXT_ELEMENTS = new Set(/** @type {const} */ (['textarea', 'script', 'style', 'title']));
-
-/** @typedef {typeof RAW_TEXT_ELEMENTS extends Set<infer T> ? T : never} RawTextElement */
+/** List of elements that require raw contents and should not have SSR comments put in them */
+const RAW_TEXT_ELEMENTS = /** @type {const} */ (['textarea', 'script', 'style', 'title']);
 
 /** @param {string} name */
 export function is_raw_text_element(name) {
-	return RAW_TEXT_ELEMENTS.has(/** @type {RawTextElement} */ (name));
+	return RAW_TEXT_ELEMENTS.includes(/** @type {typeof RAW_TEXT_ELEMENTS[number]} */ (name));
 }
 
 // Matches valid HTML/SVG/MathML element names and custom element names.

From c01e598fff2a851323fb61c6325ef51b87f019fd Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Tue, 26 May 2026 23:18:51 +0200
Subject: [PATCH 038/222] fix: avoid waterfall-warning when async resolves to
 same value (#18297)

---
 .changeset/swift-terms-exist.md               |  5 +++++
 .../internal/client/reactivity/deriveds.js    |  6 +++---
 .../async-derived-same-value/_config.js       | 19 +++++++++++++++++++
 .../async-derived-same-value/main.svelte      | 12 ++++++++++++
 4 files changed, 39 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/swift-terms-exist.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-derived-same-value/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-derived-same-value/main.svelte

diff --git a/.changeset/swift-terms-exist.md b/.changeset/swift-terms-exist.md
new file mode 100644
index 0000000000..cc69f1b3b1
--- /dev/null
+++ b/.changeset/swift-terms-exist.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: avoid waterfall-warning when async resolves to same value
diff --git a/packages/svelte/src/internal/client/reactivity/deriveds.js b/packages/svelte/src/internal/client/reactivity/deriveds.js
index 7ea6de6306..fd64f3b45d 100644
--- a/packages/svelte/src/internal/client/reactivity/deriveds.js
+++ b/packages/svelte/src/internal/client/reactivity/deriveds.js
@@ -230,9 +230,7 @@ export function async_derived(fn, label, location) {
 					signal.f ^= ERROR_VALUE;
 				}
 
-				internal_set(signal, value);
-
-				if (DEV && location !== undefined) {
+				if (DEV && location !== undefined && !signal.equals(value)) {
 					recent_async_deriveds.add(signal);
 
 					setTimeout(() => {
@@ -242,6 +240,8 @@ export function async_derived(fn, label, location) {
 						}
 					});
 				}
+
+				internal_set(signal, value);
 			}
 
 			batch.deactivate();
diff --git a/packages/svelte/tests/runtime-runes/samples/async-derived-same-value/_config.js b/packages/svelte/tests/runtime-runes/samples/async-derived-same-value/_config.js
new file mode 100644
index 0000000000..b4eb464e23
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-derived-same-value/_config.js
@@ -0,0 +1,19 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	compileOptions: { dev: true },
+	async test({ assert, target, warnings }) {
+		await tick();
+		const [button] = target.querySelectorAll('button');
+
+		button.click();
+		await tick();
+		assert.htmlEqual(target.innerHTML, '<button>1</button>');
+
+		button.click();
+		await tick();
+		assert.htmlEqual(target.innerHTML, '<button>1</button>');
+		assert.deepEqual(warnings, []);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-derived-same-value/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-derived-same-value/main.svelte
new file mode 100644
index 0000000000..78475047cd
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-derived-same-value/main.svelte
@@ -0,0 +1,12 @@
+<script>
+	let count = $state(0);
+	let unreactive = $derived(await push(count));
+
+	function push(v) {
+		if (!v) return v;
+
+		return Promise.resolve(1);
+	}
+</script>
+
+<button onclick={() => count++}>{unreactive}</button>

From b40c359d44196b7b87745259243333763ed61ec5 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Tue, 26 May 2026 23:37:17 +0200
Subject: [PATCH 039/222] fix: don't assume boundary exists during
 increment/decrement (#18289)

Follow-up to #18273 (not merged yet hence no changeset here): We can run
into a null-pointer when wanting to increment/decrement inside an effect
root that is outside a the component tree. Similarly, if not using the
component logic to unset context at the right time we gotta do it
"manually" inside `save`.

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
Co-authored-by: vercel[bot] <35613825+vercel[bot]@users.noreply.github.com>
---
 .../client/visitors/VariableDeclaration.js    |  4 ++--
 packages/svelte/src/compiler/utils/ast.js     |  5 ++--
 .../src/internal/client/reactivity/async.js   | 23 +++++++++++++++----
 .../main.svelte                               | 11 ---------
 .../_config.js                                |  8 ++++++-
 .../main.svelte                               | 19 +++++++++++++++
 .../_config.js                                | 14 +++++++++++
 .../main.svelte                               | 15 ++++++++++++
 8 files changed, 78 insertions(+), 21 deletions(-)
 delete mode 100644 packages/svelte/tests/runtime-runes/samples/async-async-disconnected-effect-root/main.svelte
 rename packages/svelte/tests/runtime-runes/samples/{async-async-disconnected-effect-root => async-disconnected-effect-root}/_config.js (57%)
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-disconnected-effect-root/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-unset-context-after-restore/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-unset-context-after-restore/main.svelte

diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
index dffa79cd7a..8b4891da8e 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
@@ -213,7 +213,7 @@ export function VariableDeclaration(node, context) {
 							location ? b.literal(location) : undefined
 						);
 
-						call = should_save ? save(call) : b.await(call);
+						call = should_save ? save(call, true) : b.await(call);
 
 						declarations.push(b.declarator(declarator.id, call));
 					} else {
@@ -251,7 +251,7 @@ export function VariableDeclaration(node, context) {
 								location ? b.literal(location) : undefined
 							);
 
-							call = should_save ? save(call) : b.await(call);
+							call = should_save ? save(call, true) : b.await(call);
 						}
 
 						declarations.push(b.declarator(id, call));
diff --git a/packages/svelte/src/compiler/utils/ast.js b/packages/svelte/src/compiler/utils/ast.js
index 75aadd905b..8d6df28f31 100644
--- a/packages/svelte/src/compiler/utils/ast.js
+++ b/packages/svelte/src/compiler/utils/ast.js
@@ -633,7 +633,8 @@ export function has_await_expression(node) {
 /**
  * Turns `await ...` to `(await $.save(...))()`
  * @param {ESTree.Expression} expression
+ * @param {boolean} unset
  */
-export function save(expression) {
-	return b.call(b.await(b.call('$.save', expression)));
+export function save(expression, unset = false) {
+	return b.call(b.await(b.call('$.save', expression, unset && b.true)));
 }
diff --git a/packages/svelte/src/internal/client/reactivity/async.js b/packages/svelte/src/internal/client/reactivity/async.js
index 12c5e9baa5..10cdb40c57 100644
--- a/packages/svelte/src/internal/client/reactivity/async.js
+++ b/packages/svelte/src/internal/client/reactivity/async.js
@@ -25,6 +25,7 @@ import {
 	set_reactivity_loss_tracker
 } from './deriveds.js';
 import { aborted } from './effects.js';
+import { queue_micro_task } from '../dom/task.js';
 
 /**
  * @param {Blocker[]} blockers
@@ -148,13 +149,25 @@ export function capture() {
  * `await a + b` becomes `(await $.save(a))() + b`
  * @template T
  * @param {Promise<T>} promise
+ * @param {boolean} unset
  * @returns {Promise<() => T>}
  */
-export async function save(promise) {
+export async function save(promise, unset) {
+	var batch = current_batch;
 	var restore = capture();
 	var value = await promise;
 
 	return () => {
+		if (unset) {
+			// If this is happening outside the context of an async derived,
+			// context will not automatically be unset
+			queue_micro_task(() => {
+				if (batch === current_batch) {
+					unset_context();
+				}
+			});
+		}
+
 		restore();
 		return value;
 	};
@@ -352,15 +365,15 @@ export function wait(blockers) {
  */
 export function increment_pending() {
 	var effect = /** @type {Effect} */ (active_effect);
-	var boundary = /** @type {Boundary} */ (effect.b);
+	var boundary = effect.b; // undefined if called outside the render tree, e.g. a standalone $effect.root
 	var batch = /** @type {Batch} */ (current_batch);
-	var blocking = boundary.is_rendered();
+	var blocking = !!boundary?.is_rendered();
 
-	boundary.update_pending_count(1, batch);
+	boundary?.update_pending_count(1, batch);
 	batch.increment(blocking, effect);
 
 	return () => {
-		boundary.update_pending_count(-1, batch);
+		boundary?.update_pending_count(-1, batch);
 		batch.decrement(blocking, effect);
 	};
 }
diff --git a/packages/svelte/tests/runtime-runes/samples/async-async-disconnected-effect-root/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-async-disconnected-effect-root/main.svelte
deleted file mode 100644
index 37c8919023..0000000000
--- a/packages/svelte/tests/runtime-runes/samples/async-async-disconnected-effect-root/main.svelte
+++ /dev/null
@@ -1,11 +0,0 @@
-<script>
-	setTimeout(() => {
-		$effect.root(() => {
-			async function fn() {
-				const value = $derived(await 1);
-				return { get value() { return value } };
-			}
-			fn().then(r => console.log(r.value));
-		})
-	})
-</script>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-async-disconnected-effect-root/_config.js b/packages/svelte/tests/runtime-runes/samples/async-disconnected-effect-root/_config.js
similarity index 57%
rename from packages/svelte/tests/runtime-runes/samples/async-async-disconnected-effect-root/_config.js
rename to packages/svelte/tests/runtime-runes/samples/async-disconnected-effect-root/_config.js
index ecf048abc3..fdc773751b 100644
--- a/packages/svelte/tests/runtime-runes/samples/async-async-disconnected-effect-root/_config.js
+++ b/packages/svelte/tests/runtime-runes/samples/async-disconnected-effect-root/_config.js
@@ -1,9 +1,15 @@
+import { tick } from 'svelte';
 import { test } from '../../test';
 
 export default test({
 	// Test that an async derived inside an $effect.root not connected to the component tree still works
 	async test({ assert, logs }) {
 		await new Promise((resolve) => setTimeout(resolve, 10));
-		assert.deepEqual(logs, [1]);
+		assert.deepEqual(logs, [1, 1]);
+		const [button] = document.querySelectorAll('button');
+
+		button.click();
+		await tick();
+		assert.deepEqual(logs, [1, 1, 2]);
 	}
 });
diff --git a/packages/svelte/tests/runtime-runes/samples/async-disconnected-effect-root/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-disconnected-effect-root/main.svelte
new file mode 100644
index 0000000000..3b42acf171
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-disconnected-effect-root/main.svelte
@@ -0,0 +1,19 @@
+<script>
+	let increment;
+
+	setTimeout(() => {
+		$effect.root(() => {
+			async function fn() {
+				let count = $state(1);
+				increment = () => { count++; };
+				const value = $derived(await count);
+				$effect.pre(() => console.log(value))
+				return { get value() { return value } };
+			}
+			fn().then(r => console.log(r.value));
+		})
+	})
+
+</script>
+
+<button onclick={() => increment()}>increment</button>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-unset-context-after-restore/_config.js b/packages/svelte/tests/runtime-runes/samples/async-unset-context-after-restore/_config.js
new file mode 100644
index 0000000000..ad543e91ae
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-unset-context-after-restore/_config.js
@@ -0,0 +1,14 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, logs }) {
+		await new Promise((resolve) => setTimeout(resolve, 10));
+		assert.deepEqual(logs, [1, 1]);
+		const [button] = document.querySelectorAll('button');
+
+		button.click();
+		await tick();
+		assert.deepEqual(logs, [1, 1, 2]);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-unset-context-after-restore/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-unset-context-after-restore/main.svelte
new file mode 100644
index 0000000000..a39c75fb94
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-unset-context-after-restore/main.svelte
@@ -0,0 +1,15 @@
+<script>
+	let increment;
+
+	async function fn() {
+		let count = $state(1);
+		increment = () => { count++; };
+		const value = $derived(await count);
+		$effect.pre(() => console.log(value))
+		return { get value() { return value } };
+	}
+	fn().then(r => console.log(r.value));
+
+</script>
+
+<button onclick={() => increment()}>increment</button>

From ec08dbc7ee156d34816586feb49bb8650579e41f Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 27 May 2026 04:20:27 -0400
Subject: [PATCH 040/222] fix: only unlink batch if we're done with it (#18298)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

alternative to #18296 — no need to make batches relinkable if we only
unlink them when we're fully done with them
---
 .changeset/khaki-states-train.md              |  5 +++
 .../src/internal/client/reactivity/batch.js   | 31 +++++++++----------
 2 files changed, 19 insertions(+), 17 deletions(-)
 create mode 100644 .changeset/khaki-states-train.md

diff --git a/.changeset/khaki-states-train.md b/.changeset/khaki-states-train.md
new file mode 100644
index 0000000000..5d4054fb15
--- /dev/null
+++ b/.changeset/khaki-states-train.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: properly unlink batches
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 08e8cf24c4..21e2cc6922 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -393,31 +393,30 @@ export class Batch {
 
 		var next_batch = /** @type {Batch | null} */ (/** @type {unknown} */ (current_batch));
 
-		if (this.linked && this.#pending === 0) {
+		if (this.#pending === 0 && (this.#roots.length === 0 || next_batch !== null)) {
 			this.#unlink();
-		}
 
-		// Order matters here - we need to commit and THEN continue flushing new batches, not the other way around,
-		// else we could start flushing a new batch and then, if it has pending work, rebase it right afterwards, which is wrong.
-		// In sync mode flushSync can cause #commit to wrongfully think that there needs to be a rebase, so we only do it in async mode
-		// TODO fix the underlying cause, otherwise this will likely regress when non-async mode is removed
-		if (async_mode_flag && !this.linked) {
-			this.#commit();
-			// Rebases can activate other batches or null it out, therefore restore the new one here
-			current_batch = next_batch;
+			// Order matters here - we need to commit and THEN continue flushing new batches, not the other way around,
+			// else we could start flushing a new batch and then, if it has pending work, rebase it right afterwards, which is wrong.
+			// In sync mode flushSync can cause #commit to wrongfully think that there needs to be a rebase, so we only do it in async mode
+			// TODO fix the underlying cause, otherwise this will likely regress when non-async mode is removed
+			if (async_mode_flag) {
+				this.#commit();
+				// Rebases can activate other batches or null it out, therefore restore the new one here
+				current_batch = next_batch;
+			}
 		}
 
 		// Edge case: During traversal new branches might create effects that run immediately and set state,
 		// causing an effect and therefore a root to be scheduled again. We need to traverse the current batch
 		// once more in that case - most of the time this will just clean up dirty branches.
 		if (this.#roots.length > 0) {
-			if (next_batch === null) {
+			if (next_batch !== null) {
+				const batch = next_batch;
+				batch.#roots.push(...this.#roots.filter((r) => !batch.#roots.includes(r)));
+			} else {
 				next_batch = this;
-				this.#link();
 			}
-
-			const batch = next_batch;
-			batch.#roots.push(...this.#roots.filter((r) => !batch.#roots.includes(r)));
 		}
 
 		if (next_batch !== null) {
@@ -644,8 +643,6 @@ export class Batch {
 	}
 
 	#commit() {
-		this.#unlink();
-
 		// If there are other pending batches, they now need to be 'rebased' —
 		// in other words, we re-run block/async effects with the newly
 		// committed state, unless the batch in question has a more

From e705369dee060e74ad9456e45824f36b1ee3c6cf Mon Sep 17 00:00:00 2001
From: Elliott Johnson <hello@ell.iott.dev>
Date: Wed, 27 May 2026 12:41:35 -0600
Subject: [PATCH 041/222] fix: propagate async @const blockers through closure
 references (#18309)

Right now, if you have the following:

```svelte
{@const data = await foo}
<p>{(() => data)()}<p>
```

It will blow up during CSR, because it tries to read `data` before it
exists. The solution to this is to consider references inside closures
as blockers for those closures. This _does_ mean we'll overblock in some
circumstances, such as:

```svelte
{@const data = await foo}
<button onclick={() => data}>foo<button>
```

But I wonder if that's actually incorrect? If the user were to click
`onclick` before `data` is ready, it would blow up.

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/iife-await-const-blocker.md             |  5 +++++
 .../3-transform/client/visitors/shared/utils.js    |  2 +-
 packages/svelte/src/compiler/phases/nodes.js       |  4 ++--
 .../samples/async-each-const-await-iife/_config.js | 14 ++++++++++++++
 .../async-each-const-await-iife/main.svelte        | 10 ++++++++++
 5 files changed, 32 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/iife-await-const-blocker.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-each-const-await-iife/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-each-const-await-iife/main.svelte

diff --git a/.changeset/iife-await-const-blocker.md b/.changeset/iife-await-const-blocker.md
new file mode 100644
index 0000000000..2b5c4f0323
--- /dev/null
+++ b/.changeset/iife-await-const-blocker.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: propagate async `@const` blockers through closure references so template expressions like `{(() => host)()}` correctly wait for the awaited value
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js
index 1f3c7b2256..51c84dd01c 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js
@@ -52,7 +52,7 @@ export class Memoizer {
 	 * @param {ExpressionMetadata} metadata
 	 */
 	check_blockers(metadata) {
-		for (const binding of metadata.dependencies) {
+		for (const binding of metadata.references) {
 			if (binding.blocker) {
 				this.#blockers.add(binding.blocker);
 			}
diff --git a/packages/svelte/src/compiler/phases/nodes.js b/packages/svelte/src/compiler/phases/nodes.js
index 2e54f333a8..48ebacb50b 100644
--- a/packages/svelte/src/compiler/phases/nodes.js
+++ b/packages/svelte/src/compiler/phases/nodes.js
@@ -102,8 +102,8 @@ export class ExpressionMetadata {
 		if (!this.#blockers) {
 			this.#blockers = new Set();
 
-			for (const d of this.dependencies) {
-				if (d.blocker) this.#blockers.add(d.blocker);
+			for (const r of this.references) {
+				if (r.blocker) this.#blockers.add(r.blocker);
 			}
 		}
 
diff --git a/packages/svelte/tests/runtime-runes/samples/async-each-const-await-iife/_config.js b/packages/svelte/tests/runtime-runes/samples/async-each-const-await-iife/_config.js
new file mode 100644
index 0000000000..958c3023f1
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-each-const-await-iife/_config.js
@@ -0,0 +1,14 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+// Tests that an IIFE referencing an `await` @const inside an {#each} block
+// correctly registers the async dependency so the template waits for the
+// resolved value instead of rendering with `undefined`.
+export default test({
+	mode: ['client', 'hydrate', 'async-server'],
+	ssrHtml: '<p>example.com</p>',
+	async test({ assert, target }) {
+		await tick();
+		assert.htmlEqual(target.innerHTML, '<p>example.com</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-each-const-await-iife/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-each-const-await-iife/main.svelte
new file mode 100644
index 0000000000..e0ccbb7892
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-each-const-await-iife/main.svelte
@@ -0,0 +1,10 @@
+<script>
+	async function get_host() {
+		return 'example.com';
+	}
+</script>
+
+{#each { length: 1 } as nothing}
+	{@const host = await get_host()}
+	<p>{(() => host)()}</p>
+{/each}

From d4be4e297365030b5cbcb676bda133f2840816b2 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Wed, 27 May 2026 21:02:19 +0200
Subject: [PATCH 042/222] chore: ensure treeshaking test runs during CI
 (#18302)

Would've caught the regression in #18250 - without this the tests were
all green, giving a false sense of "this is correct"
---
 packages/svelte/package.json | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index b9bb48aa72..a5af1e6ee9 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -138,7 +138,7 @@
     "templating"
   ],
   "scripts": {
-    "build": "rollup -c && pnpm generate",
+    "build": "rollup -c && pnpm generate && node scripts/check-treeshakeability.js",
     "dev": "node scripts/process-messages -w & rollup -cw",
     "check": "tsc --project tsconfig.runtime.json && tsc && cd ./tests/types && tsc",
     "check:tsgo": "tsgo --project tsconfig.runtime.json --skipLibCheck && tsgo --skipLibCheck",
@@ -146,7 +146,7 @@
     "generate": "node scripts/process-messages && node ./scripts/generate-types.js",
     "generate:version": "node ./scripts/generate-version.js",
     "generate:types": "node ./scripts/generate-types.js && tsc -p tsconfig.generated.json",
-    "prepublishOnly": "pnpm build && node scripts/check-treeshakeability.js",
+    "prepublishOnly": "pnpm build",
     "knip": "pnpm dlx knip"
   },
   "devDependencies": {

From 0da9f9e2ab515da16d624c5bc48b554beb179f92 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 27 May 2026 15:58:57 -0400
Subject: [PATCH 043/222] fix: disallow effect creation after `await` (#18299)

We incorrectly restore effect context after an`$derived(await ...)` if
it occurs inside an async function, but only for those, no other `await`
expressions. This is buggy and wrong. We only want to restore context
_inside_ an async derived expression (including template expressions)`
so that `await a + b` works correctly.

It's possible that this will be a breaking change (albeit not
semver-violating, because `experimental`) for some people if they are
creating effects after an `await` (other than at the top level of a
component). This is regrettable, but it should never have worked in the
first place.
---
 .../docs/98-reference/.generated/client-errors.md |  4 ++++
 packages/svelte/messages/client-errors/errors.md  |  4 ++++
 .../phases/2-analyze/visitors/AwaitExpression.js  |  3 +--
 .../client/visitors/VariableDeclaration.js        | 11 ++---------
 packages/svelte/src/compiler/utils/ast.js         |  5 ++---
 .../src/internal/client/reactivity/async.js       | 15 +--------------
 .../async-disconnected-effect-root/main.svelte    |  3 +--
 .../samples/async-effect-orphan/_config.js        | 12 ++++++++++++
 .../samples/async-effect-orphan/main.svelte       | 14 ++++++++++++++
 .../async-unset-context-after-restore/_config.js  | 14 --------------
 .../async-unset-context-after-restore/main.svelte | 15 ---------------
 11 files changed, 41 insertions(+), 59 deletions(-)
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-effect-orphan/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-effect-orphan/main.svelte
 delete mode 100644 packages/svelte/tests/runtime-runes/samples/async-unset-context-after-restore/_config.js
 delete mode 100644 packages/svelte/tests/runtime-runes/samples/async-unset-context-after-restore/main.svelte

diff --git a/documentation/docs/98-reference/.generated/client-errors.md b/documentation/docs/98-reference/.generated/client-errors.md
index 7fccac5808..2ab442afc3 100644
--- a/documentation/docs/98-reference/.generated/client-errors.md
+++ b/documentation/docs/98-reference/.generated/client-errors.md
@@ -88,6 +88,10 @@ Effect cannot be created inside a `$derived` value that was not itself created i
 `%rune%` can only be used inside an effect (e.g. during component initialisation)
 ```
 
+Effects can only be created while a parent effect is running. This means that they cannot, for example, be created inside an event handler or after an `await` expression (unless the `await` occurs directly inside a component's `<script>` tag, and not inside an async function).
+
+In very rare cases, it is appropriate to use [`$effect.root`]($effect#$effect.root) so that you can create effects outside the normal component lifecycle.
+
 ### effect_pending_outside_reaction
 
 ```
diff --git a/packages/svelte/messages/client-errors/errors.md b/packages/svelte/messages/client-errors/errors.md
index 3f20cb989d..3b00d1516b 100644
--- a/packages/svelte/messages/client-errors/errors.md
+++ b/packages/svelte/messages/client-errors/errors.md
@@ -60,6 +60,10 @@ The key expression in a keyed each block must return the same value when called
 
 > `%rune%` can only be used inside an effect (e.g. during component initialisation)
 
+Effects can only be created while a parent effect is running. This means that they cannot, for example, be created inside an event handler or after an `await` expression (unless the `await` occurs directly inside a component's `<script>` tag, and not inside an async function).
+
+In very rare cases, it is appropriate to use [`$effect.root`]($effect#$effect.root) so that you can create effects outside the normal component lifecycle.
+
 ## effect_pending_outside_reaction
 
 > `$effect.pending()` can only be called inside an effect or derived
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/AwaitExpression.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/AwaitExpression.js
index 545bc3be27..5a54d62471 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/AwaitExpression.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/AwaitExpression.js
@@ -115,8 +115,7 @@ function is_last_evaluated_expression(path, node) {
 				break;
 
 			case 'MemberExpression':
-				if (parent.computed && node === parent.object) return false;
-				break;
+				return false;
 
 			case 'ObjectExpression':
 				if (node !== parent.properties.at(-1)) return false;
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
index 8b4891da8e..72685a8e83 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
@@ -194,11 +194,6 @@ export function VariableDeclaration(node, context) {
 					/** @type {CallExpression} */ (init)
 				);
 
-				// for now, only wrap async derived in $.save if it's not
-				// a top-level instance derived. TODO in future maybe we
-				// can dewaterfall all of them?
-				const should_save = context.state.is_instance && context.state.scope.function_depth > 1;
-
 				if (declarator.id.type === 'Identifier') {
 					let expression = /** @type {Expression} */ (context.visit(value));
 
@@ -213,9 +208,7 @@ export function VariableDeclaration(node, context) {
 							location ? b.literal(location) : undefined
 						);
 
-						call = should_save ? save(call, true) : b.await(call);
-
-						declarations.push(b.declarator(declarator.id, call));
+						declarations.push(b.declarator(declarator.id, b.await(call)));
 					} else {
 						if (rune === '$derived') expression = b.thunk(expression);
 
@@ -251,7 +244,7 @@ export function VariableDeclaration(node, context) {
 								location ? b.literal(location) : undefined
 							);
 
-							call = should_save ? save(call, true) : b.await(call);
+							call = b.await(call);
 						}
 
 						declarations.push(b.declarator(id, call));
diff --git a/packages/svelte/src/compiler/utils/ast.js b/packages/svelte/src/compiler/utils/ast.js
index 8d6df28f31..75aadd905b 100644
--- a/packages/svelte/src/compiler/utils/ast.js
+++ b/packages/svelte/src/compiler/utils/ast.js
@@ -633,8 +633,7 @@ export function has_await_expression(node) {
 /**
  * Turns `await ...` to `(await $.save(...))()`
  * @param {ESTree.Expression} expression
- * @param {boolean} unset
  */
-export function save(expression, unset = false) {
-	return b.call(b.await(b.call('$.save', expression, unset && b.true)));
+export function save(expression) {
+	return b.call(b.await(b.call('$.save', expression)));
 }
diff --git a/packages/svelte/src/internal/client/reactivity/async.js b/packages/svelte/src/internal/client/reactivity/async.js
index 10cdb40c57..89115108d5 100644
--- a/packages/svelte/src/internal/client/reactivity/async.js
+++ b/packages/svelte/src/internal/client/reactivity/async.js
@@ -25,7 +25,6 @@ import {
 	set_reactivity_loss_tracker
 } from './deriveds.js';
 import { aborted } from './effects.js';
-import { queue_micro_task } from '../dom/task.js';
 
 /**
  * @param {Blocker[]} blockers
@@ -149,25 +148,13 @@ export function capture() {
  * `await a + b` becomes `(await $.save(a))() + b`
  * @template T
  * @param {Promise<T>} promise
- * @param {boolean} unset
  * @returns {Promise<() => T>}
  */
-export async function save(promise, unset) {
-	var batch = current_batch;
+export async function save(promise) {
 	var restore = capture();
 	var value = await promise;
 
 	return () => {
-		if (unset) {
-			// If this is happening outside the context of an async derived,
-			// context will not automatically be unset
-			queue_micro_task(() => {
-				if (batch === current_batch) {
-					unset_context();
-				}
-			});
-		}
-
 		restore();
 		return value;
 	};
diff --git a/packages/svelte/tests/runtime-runes/samples/async-disconnected-effect-root/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-disconnected-effect-root/main.svelte
index 3b42acf171..0ddb7d01d7 100644
--- a/packages/svelte/tests/runtime-runes/samples/async-disconnected-effect-root/main.svelte
+++ b/packages/svelte/tests/runtime-runes/samples/async-disconnected-effect-root/main.svelte
@@ -6,14 +6,13 @@
 			async function fn() {
 				let count = $state(1);
 				increment = () => { count++; };
+				$effect.pre(() => console.log(count))
 				const value = $derived(await count);
-				$effect.pre(() => console.log(value))
 				return { get value() { return value } };
 			}
 			fn().then(r => console.log(r.value));
 		})
 	})
-
 </script>
 
 <button onclick={() => increment()}>increment</button>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-effect-orphan/_config.js b/packages/svelte/tests/runtime-runes/samples/async-effect-orphan/_config.js
new file mode 100644
index 0000000000..b76ea85bfd
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-effect-orphan/_config.js
@@ -0,0 +1,12 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, logs }) {
+		await tick();
+
+		assert.deepEqual(logs, [
+			`effect_orphan\n\`$effect\` can only be used inside an effect (e.g. during component initialisation)\nhttps://svelte.dev/e/effect_orphan`
+		]);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-effect-orphan/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-effect-orphan/main.svelte
new file mode 100644
index 0000000000..086a048025
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-effect-orphan/main.svelte
@@ -0,0 +1,14 @@
+<script>
+	async function foo() {
+		await 0;
+		$effect(() => {
+			console.log('this effect is orphaned');
+		});
+	}
+
+	try {
+		await foo();
+	} catch (e) {
+		console.log(e.message)
+	}
+</script>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-unset-context-after-restore/_config.js b/packages/svelte/tests/runtime-runes/samples/async-unset-context-after-restore/_config.js
deleted file mode 100644
index ad543e91ae..0000000000
--- a/packages/svelte/tests/runtime-runes/samples/async-unset-context-after-restore/_config.js
+++ /dev/null
@@ -1,14 +0,0 @@
-import { tick } from 'svelte';
-import { test } from '../../test';
-
-export default test({
-	async test({ assert, logs }) {
-		await new Promise((resolve) => setTimeout(resolve, 10));
-		assert.deepEqual(logs, [1, 1]);
-		const [button] = document.querySelectorAll('button');
-
-		button.click();
-		await tick();
-		assert.deepEqual(logs, [1, 1, 2]);
-	}
-});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-unset-context-after-restore/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-unset-context-after-restore/main.svelte
deleted file mode 100644
index a39c75fb94..0000000000
--- a/packages/svelte/tests/runtime-runes/samples/async-unset-context-after-restore/main.svelte
+++ /dev/null
@@ -1,15 +0,0 @@
-<script>
-	let increment;
-
-	async function fn() {
-		let count = $state(1);
-		increment = () => { count++; };
-		const value = $derived(await count);
-		$effect.pre(() => console.log(value))
-		return { get value() { return value } };
-	}
-	fn().then(r => console.log(r.value));
-
-</script>
-
-<button onclick={() => increment()}>increment</button>

From 638ab370a561f97552229589f2f334655426fe5c Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Wed, 27 May 2026 22:52:40 +0200
Subject: [PATCH 044/222] fix: prevent batch unlinking twice (#18303)

Merged #18298 a bit too soon - there's still a situation which can
corrput the linked list: If we merge one batch into another, it will
unlink the batch immediately. But `discard` also calls it, running the
unlink logic again, which can corrupt the linked list.

Sketch:

1. Batch A is pending.
2. Batch B starts later, intersects A, resolves first, and merges into
A.
3. B is unlinked immediately, but `A.oncommit(() => B.discard())`
remains.
4. Independent batch C is created while A is still pending and is linked
after A.
5. A commits, calls `B.discard()`, and B's stale `#prev`/`#next` can set
`A.#next = null` / `last_batch = A`, disconnecting C.

Not able to produce a failing test from it but it's definitely a fix we
need to make.

Also moved `#link` into a constructor, because it is (and should be)
used only once.

Also made the action after an error `discard` instead of just `#unlink`
because this batch is done for and e.g. pending `settled` should
resolve, too.
---
 .../src/internal/client/reactivity/batch.js   | 32 +++++++++++--------
 1 file changed, 18 insertions(+), 14 deletions(-)

diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 21e2cc6922..74448da03a 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -214,6 +214,18 @@ export class Batch {
 
 	#decrement_queued = false;
 
+	constructor() {
+		// link batch
+		if (last_batch === null) {
+			first_batch = last_batch = this;
+		} else {
+			last_batch.#next = this;
+			this.#prev = last_batch;
+		}
+
+		last_batch = this;
+	}
+
 	#is_deferred() {
 		if (this.is_fork) return true;
 
@@ -327,11 +339,11 @@ export class Batch {
 			} catch (e) {
 				reset_all(root);
 				// If there's no async work left, this branch is now dead and needs
-				// to be unlinked to not become a zombie that is never cleaned up.
+				// to be discarded to not become a zombie that is never cleaned up.
 				// See https://github.com/sveltejs/svelte/issues/18221#issuecomment-4497918414
 				// for a (non-minimal) reproduction that demonstrates a case where this is necessary
 				// to not get follow-up false-positives via "batch has scheduled roots" invariant errors.
-				if (!this.#is_deferred()) this.#unlink();
+				if (!this.#is_deferred()) this.discard();
 				throw e;
 			}
 		}
@@ -852,7 +864,6 @@ export class Batch {
 	static ensure() {
 		if (current_batch === null) {
 			const batch = (current_batch = new Batch());
-			batch.#link();
 
 			if (!is_processing && !is_flushing_sync) {
 				queue_micro_task(() => {
@@ -972,18 +983,11 @@ export class Batch {
 		this.#roots.push(e);
 	}
 
-	#link() {
-		if (last_batch === null) {
-			first_batch = last_batch = this;
-		} else {
-			last_batch.#next = this;
-			this.#prev = last_batch;
-		}
-
-		last_batch = this;
-	}
-
 	#unlink() {
+		// #merge calls #unlink, discard later on does it again - prevent
+		// running it multiple times to not corrupt the linked list
+		if (!this.linked) return;
+
 		var prev = this.#prev;
 		var next = this.#next;
 

From 49538608356eabc74fc182b03449112a4fa1f12d Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Wed, 27 May 2026 22:53:15 +0200
Subject: [PATCH 045/222] chore: remove unused class property (#18307)

remnant of blocker approach
---
 packages/svelte/src/internal/client/reactivity/batch.js | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 74448da03a..8dbcacf429 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -127,13 +127,6 @@ export class Batch {
 	 */
 	previous = new Map();
 
-	/**
-	 * Async effects which this batch doesn't take into account anymore when calculating blockers,
-	 * as it has a value for it already.
-	 * @type {Set<Effect>}
-	 */
-	unblocked = new Set();
-
 	/**
 	 * When the batch is committed (and the DOM is updated), we need to remove old branches
 	 * and append new ones by calling the functions added inside (if/each/key/etc) blocks

From 688671ec2328ed1739a2fb0ecf74a98d35d5e2b9 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 27 May 2026 17:20:15 -0400
Subject: [PATCH 046/222] chore: fix printing in sandbox (#18311)

when `PRINT` is true, the sandbox should write out the printed code. at
present it doesn't do this if `AST` is not also true
---
 playgrounds/sandbox/run.js | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/playgrounds/sandbox/run.js b/playgrounds/sandbox/run.js
index f79243d4e7..3b0602f716 100644
--- a/playgrounds/sandbox/run.js
+++ b/playgrounds/sandbox/run.js
@@ -59,19 +59,21 @@ for (const generate of /** @type {const} */ (['client', 'server'])) {
 		mkdirp(path.dirname(output_js));
 
 		if (generate === 'client') {
-			if (AST) {
+			if (AST || PRINT) {
 				const ast = parse(source, {
 					modern: true
 				});
 
-				write(
-					`${cwd}/output/ast/${file}.json`,
-					JSON.stringify(
-						ast,
-						(key, value) => (typeof value === 'bigint' ? ['BigInt', value.toString()] : value),
-						'\t'
-					)
-				);
+				if (AST) {
+					write(
+						`${cwd}/output/ast/${file}.json`,
+						JSON.stringify(
+							ast,
+							(key, value) => (typeof value === 'bigint' ? ['BigInt', value.toString()] : value),
+							'\t'
+						)
+					);
+				}
 
 				if (PRINT) {
 					const printed = print(ast);

From 0bb715d3cfe51134756e79b6193dacccfa77361f Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Wed, 27 May 2026 17:47:19 -0400
Subject: [PATCH 047/222] Version Packages (#18255)

This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.


# Releases
## svelte@5.55.10

### Patch Changes

- fix: unlink errored and otherwise finished batch
([#18264](https://github.com/sveltejs/svelte/pull/18264))

- perf: walk composedPath() directly in delegated event propagation
([#18268](https://github.com/sveltejs/svelte/pull/18268))

- fix: transfer effects when merging batches
([#18254](https://github.com/sveltejs/svelte/pull/18254))

- fix: allow `$derived(await ...)` in disconnected effect roots
([#18273](https://github.com/sveltejs/svelte/pull/18273))

- fix: remove temporary raw-text hydration markers
([#18269](https://github.com/sveltejs/svelte/pull/18269))

- fix: propagate async `@const` blockers through closure references so
template expressions like `{(() => host)()}` correctly wait for the
awaited value ([#18309](https://github.com/sveltejs/svelte/pull/18309))

- fix: properly unlink batches
([#18298](https://github.com/sveltejs/svelte/pull/18298))

- fix: settle discarded batch
([#18290](https://github.com/sveltejs/svelte/pull/18290))

- fix: declare `let:` directives before `{@const}` declarations on
slotted elements
([#18271](https://github.com/sveltejs/svelte/pull/18271))

- fix: resume outro-ed branches if they were kept around
([#18291](https://github.com/sveltejs/svelte/pull/18291))

- fix: avoid waterfall-warning when async resolves to same value
([#18297](https://github.com/sveltejs/svelte/pull/18297))

- fix: correctly coordinate component-level effects inside async blocks
([#18260](https://github.com/sveltejs/svelte/pull/18260))

- fix: make unnecessary commit work less likely
([#18263](https://github.com/sveltejs/svelte/pull/18263))

- chore: add tag name to `a11y_click_events_have_key_events` warning
([#18272](https://github.com/sveltejs/svelte/pull/18272))

- fix: catch rejected promises while merging/committing
([#18266](https://github.com/sveltejs/svelte/pull/18266))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/beige-bobcats-eat.md        |  5 ----
 .changeset/event-walk-composed-path.md |  5 ----
 .changeset/evil-stars-wave.md          |  5 ----
 .changeset/fine-corners-lay.md         |  5 ----
 .changeset/gentle-styles-hydrate.md    |  5 ----
 .changeset/iife-await-const-blocker.md |  5 ----
 .changeset/khaki-states-train.md       |  5 ----
 .changeset/neat-groups-grin.md         |  5 ----
 .changeset/quiet-rivers-melt.md        |  5 ----
 .changeset/sad-shoes-help.md           |  5 ----
 .changeset/swift-terms-exist.md        |  5 ----
 .changeset/tasty-tires-wait.md         |  5 ----
 .changeset/tired-socks-brake.md        |  5 ----
 .changeset/true-dancers-tell.md        |  5 ----
 .changeset/true-pigs-go.md             |  5 ----
 packages/svelte/CHANGELOG.md           | 34 ++++++++++++++++++++++++++
 packages/svelte/package.json           |  2 +-
 packages/svelte/src/version.js         |  2 +-
 18 files changed, 36 insertions(+), 77 deletions(-)
 delete mode 100644 .changeset/beige-bobcats-eat.md
 delete mode 100644 .changeset/event-walk-composed-path.md
 delete mode 100644 .changeset/evil-stars-wave.md
 delete mode 100644 .changeset/fine-corners-lay.md
 delete mode 100644 .changeset/gentle-styles-hydrate.md
 delete mode 100644 .changeset/iife-await-const-blocker.md
 delete mode 100644 .changeset/khaki-states-train.md
 delete mode 100644 .changeset/neat-groups-grin.md
 delete mode 100644 .changeset/quiet-rivers-melt.md
 delete mode 100644 .changeset/sad-shoes-help.md
 delete mode 100644 .changeset/swift-terms-exist.md
 delete mode 100644 .changeset/tasty-tires-wait.md
 delete mode 100644 .changeset/tired-socks-brake.md
 delete mode 100644 .changeset/true-dancers-tell.md
 delete mode 100644 .changeset/true-pigs-go.md

diff --git a/.changeset/beige-bobcats-eat.md b/.changeset/beige-bobcats-eat.md
deleted file mode 100644
index 95390c3c2e..0000000000
--- a/.changeset/beige-bobcats-eat.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: unlink errored and otherwise finished batch
diff --git a/.changeset/event-walk-composed-path.md b/.changeset/event-walk-composed-path.md
deleted file mode 100644
index 8b24573930..0000000000
--- a/.changeset/event-walk-composed-path.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-perf: walk composedPath() directly in delegated event propagation
diff --git a/.changeset/evil-stars-wave.md b/.changeset/evil-stars-wave.md
deleted file mode 100644
index b199afe1dd..0000000000
--- a/.changeset/evil-stars-wave.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: transfer effects when merging batches
diff --git a/.changeset/fine-corners-lay.md b/.changeset/fine-corners-lay.md
deleted file mode 100644
index badbc6f81f..0000000000
--- a/.changeset/fine-corners-lay.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: allow `$derived(await ...)` in disconnected effect roots
diff --git a/.changeset/gentle-styles-hydrate.md b/.changeset/gentle-styles-hydrate.md
deleted file mode 100644
index f63d4e274c..0000000000
--- a/.changeset/gentle-styles-hydrate.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: remove temporary raw-text hydration markers
diff --git a/.changeset/iife-await-const-blocker.md b/.changeset/iife-await-const-blocker.md
deleted file mode 100644
index 2b5c4f0323..0000000000
--- a/.changeset/iife-await-const-blocker.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: propagate async `@const` blockers through closure references so template expressions like `{(() => host)()}` correctly wait for the awaited value
diff --git a/.changeset/khaki-states-train.md b/.changeset/khaki-states-train.md
deleted file mode 100644
index 5d4054fb15..0000000000
--- a/.changeset/khaki-states-train.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: properly unlink batches
diff --git a/.changeset/neat-groups-grin.md b/.changeset/neat-groups-grin.md
deleted file mode 100644
index 1d615216f0..0000000000
--- a/.changeset/neat-groups-grin.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: settle discarded batch
diff --git a/.changeset/quiet-rivers-melt.md b/.changeset/quiet-rivers-melt.md
deleted file mode 100644
index 7ce1b9b2d3..0000000000
--- a/.changeset/quiet-rivers-melt.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: declare `let:` directives before `{@const}` declarations on slotted elements
diff --git a/.changeset/sad-shoes-help.md b/.changeset/sad-shoes-help.md
deleted file mode 100644
index 76db87ba95..0000000000
--- a/.changeset/sad-shoes-help.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: resume outro-ed branches if they were kept around
diff --git a/.changeset/swift-terms-exist.md b/.changeset/swift-terms-exist.md
deleted file mode 100644
index cc69f1b3b1..0000000000
--- a/.changeset/swift-terms-exist.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: avoid waterfall-warning when async resolves to same value
diff --git a/.changeset/tasty-tires-wait.md b/.changeset/tasty-tires-wait.md
deleted file mode 100644
index 0f3fd2d671..0000000000
--- a/.changeset/tasty-tires-wait.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: correctly coordinate component-level effects inside async blocks
diff --git a/.changeset/tired-socks-brake.md b/.changeset/tired-socks-brake.md
deleted file mode 100644
index 1d302ffa60..0000000000
--- a/.changeset/tired-socks-brake.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: make unnecessary commit work less likely
diff --git a/.changeset/true-dancers-tell.md b/.changeset/true-dancers-tell.md
deleted file mode 100644
index bd50b2ddc9..0000000000
--- a/.changeset/true-dancers-tell.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-"svelte": patch
----
-
-chore: add tag name to `a11y_click_events_have_key_events` warning
diff --git a/.changeset/true-pigs-go.md b/.changeset/true-pigs-go.md
deleted file mode 100644
index b4900b38fa..0000000000
--- a/.changeset/true-pigs-go.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: catch rejected promises while merging/committing
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 1f3f9d1149..ef40c5d159 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,39 @@
 # svelte
 
+## 5.55.10
+
+### Patch Changes
+
+- fix: unlink errored and otherwise finished batch ([#18264](https://github.com/sveltejs/svelte/pull/18264))
+
+- perf: walk composedPath() directly in delegated event propagation ([#18268](https://github.com/sveltejs/svelte/pull/18268))
+
+- fix: transfer effects when merging batches ([#18254](https://github.com/sveltejs/svelte/pull/18254))
+
+- fix: allow `$derived(await ...)` in disconnected effect roots ([#18273](https://github.com/sveltejs/svelte/pull/18273))
+
+- fix: remove temporary raw-text hydration markers ([#18269](https://github.com/sveltejs/svelte/pull/18269))
+
+- fix: propagate async `@const` blockers through closure references so template expressions like `{(() => host)()}` correctly wait for the awaited value ([#18309](https://github.com/sveltejs/svelte/pull/18309))
+
+- fix: properly unlink batches ([#18298](https://github.com/sveltejs/svelte/pull/18298))
+
+- fix: settle discarded batch ([#18290](https://github.com/sveltejs/svelte/pull/18290))
+
+- fix: declare `let:` directives before `{@const}` declarations on slotted elements ([#18271](https://github.com/sveltejs/svelte/pull/18271))
+
+- fix: resume outro-ed branches if they were kept around ([#18291](https://github.com/sveltejs/svelte/pull/18291))
+
+- fix: avoid waterfall-warning when async resolves to same value ([#18297](https://github.com/sveltejs/svelte/pull/18297))
+
+- fix: correctly coordinate component-level effects inside async blocks ([#18260](https://github.com/sveltejs/svelte/pull/18260))
+
+- fix: make unnecessary commit work less likely ([#18263](https://github.com/sveltejs/svelte/pull/18263))
+
+- chore: add tag name to `a11y_click_events_have_key_events` warning ([#18272](https://github.com/sveltejs/svelte/pull/18272))
+
+- fix: catch rejected promises while merging/committing ([#18266](https://github.com/sveltejs/svelte/pull/18266))
+
 ## 5.55.9
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index a5af1e6ee9..bd10bf5966 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.55.9",
+  "version": "5.55.10",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index ee05138797..638534d369 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.55.9';
+export const VERSION = '5.55.10';
 export const PUBLIC_VERSION = '5';

From 67090e8ee8a4ac3cb2926969f75cf161ace6367d Mon Sep 17 00:00:00 2001
From: Mathias Picker <48158184+MathiasWP@users.noreply.github.com>
Date: Thu, 28 May 2026 13:53:13 +0200
Subject: [PATCH 048/222] perf: store current_sources as Set for O(1)
 membership checks (#18278)

`current_sources` tracks the sources created within the active reaction
so that reading or writing them during that same reaction doesn't
trigger a re-run. It was an `Array` checked with
`Array.prototype.includes.call(...)` in three hot places: the
`state_unsafe_mutation` guard, `set()`'s destruction check, and
`schedule_possible_effect_self_invalidation`.

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/current-sources-set.md                    |  5 +++++
 .../svelte/src/internal/client/reactivity/sources.js |  3 +--
 packages/svelte/src/internal/client/runtime.js       | 12 ++++--------
 3 files changed, 10 insertions(+), 10 deletions(-)
 create mode 100644 .changeset/current-sources-set.md

diff --git a/.changeset/current-sources-set.md b/.changeset/current-sources-set.md
new file mode 100644
index 0000000000..e1a4dc43b2
--- /dev/null
+++ b/.changeset/current-sources-set.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+perf: store `current_sources` as a `Set` for O(1) membership checks
diff --git a/packages/svelte/src/internal/client/reactivity/sources.js b/packages/svelte/src/internal/client/reactivity/sources.js
index f374f6a26b..218941ab67 100644
--- a/packages/svelte/src/internal/client/reactivity/sources.js
+++ b/packages/svelte/src/internal/client/reactivity/sources.js
@@ -32,7 +32,6 @@ import {
 } from '#client/constants';
 import * as e from '../errors.js';
 import { legacy_mode_flag, tracing_mode_flag } from '../../flags/index.js';
-import { includes } from '../../shared/utils.js';
 import { tag_proxy } from '../dev/tracing.js';
 import { get_error } from '../../shared/dev.js';
 import { component_context, is_runes } from '../context.js';
@@ -158,7 +157,7 @@ export function set(source, value, should_proxy = false) {
 		(!untracking || (active_reaction.f & EAGER_EFFECT) !== 0) &&
 		is_runes() &&
 		(active_reaction.f & (DERIVED | BLOCK_EFFECT | ASYNC | EAGER_EFFECT)) !== 0 &&
-		(current_sources === null || !includes.call(current_sources, source))
+		(current_sources === null || !current_sources.has(source))
 	) {
 		e.state_unsafe_mutation();
 	}
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 87abbd71b6..8d70eee43c 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -90,18 +90,14 @@ export function set_active_effect(effect) {
 /**
  * When sources are created within a reaction, reading and writing
  * them within that reaction should not cause a re-run
- * @type {null | Source[]}
+ * @type {null | Set<Source>}
  */
 export let current_sources = null;
 
 /** @param {Value} value */
 export function push_reaction_value(value) {
 	if (active_reaction !== null && (!async_mode_flag || (active_reaction.f & DERIVED) !== 0)) {
-		if (current_sources === null) {
-			current_sources = [value];
-		} else {
-			current_sources.push(value);
-		}
+		(current_sources ??= new Set()).add(value);
 	}
 }
 
@@ -202,7 +198,7 @@ function schedule_possible_effect_self_invalidation(signal, effect, root = true)
 	var reactions = signal.reactions;
 	if (reactions === null) return;
 
-	if (!async_mode_flag && current_sources !== null && includes.call(current_sources, signal)) {
+	if (!async_mode_flag && current_sources !== null && current_sources.has(signal)) {
 		return;
 	}
 
@@ -540,7 +536,7 @@ export function get(signal) {
 		// we don't add the dependency, because that would create a memory leak
 		var destroyed = active_effect !== null && (active_effect.f & DESTROYED) !== 0;
 
-		if (!destroyed && (current_sources === null || !includes.call(current_sources, signal))) {
+		if (!destroyed && (current_sources === null || !current_sources.has(signal))) {
 			var deps = active_reaction.deps;
 
 			if ((active_reaction.f & REACTION_IS_UPDATING) !== 0) {

From 27e74c4df7b49f6b7663e00acd065a68ddaa337f Mon Sep 17 00:00:00 2001
From: Mathias Picker <48158184+MathiasWP@users.noreply.github.com>
Date: Thu, 28 May 2026 20:19:56 +0200
Subject: [PATCH 049/222] docs: add auto-generated browser support page
 (#18276)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

## Summary

Adds a [Browser
support](https://github.com/MathiasWP/svelte/blob/document-pipeline-draft/documentation/docs/07-misc/05-browser-support.md)
page listing the minimum browser versions Svelte's runtime and compiler
output require. The page (headline floor + per-feature requirements) is
auto-generated by `packages/svelte/scripts/generate-browser-support.js`,
which scans the code Svelte actually ships against the
[web-features](https://github.com/web-platform-dx/web-features) Baseline
dataset and resolves results to concrete browser versions via
[baseline-browser-mapping](https://github.com/web-platform-dx/baseline-browser-mapping).
CI fails if a PR moves the floor without regenerating the page.

For 5.55.9 the floor is **Baseline 2020**: Chrome/Edge 87, Firefox 83,
Safari 14.

## How it works

1. **Headline floor.** Each runtime entry from `pkg.exports` is bundled
with rollup using production conditions, then walked with TypeScript's
compiler API + TypeChecker. The walker (`browser-support.detector.js`)
flags any web-features ID the runtime references; the highest Baseline
year among them is the floor.
2. **Per-feature requirements.** Every user-facing surface is enumerated
programmatically — every `bind:*` from `binding_properties`, every
public subpackage export discovered via `pkg.exports` + `import * as
ns`, every rune from `RUNES`, and directives (`transition:` / `animate:`
/ `use:` / `@attach` / `{@html}` / custom elements). Each gets a
fixture, compiled and bundled like user code, then scanned. A row
appears only when the fixture's floor exceeds the runtime floor.
3. **Supplemental rules.** A handful of APIs `web-features` doesn't
catalogue (`getComputedStyle(...).zoom`, `box:
'device-pixel-content-box'`) are detected with the same type-aware
walker via a small `register_extra_rules` list with inline
justifications.
4. **Ignore sets.** `SAFE_TO_IGNORE` covers dataset bugs and
feature-detected APIs with graceful fallbacks. `BEHAVIORAL_IGNORE` hides
APIs reached only via specific user code from the headline (they still
surface as conditional rows); staleness-checked, so CI fails if an entry
no longer exists in the runtime.

Resolves #18198. Provides an answer to the long-standing #558.

## Test plan

- [ ] \`pnpm --filter svelte generate:browser-support\` regenerates the
page idempotently
- [ ] CI fails when a code change bumps the floor without regenerating
the page
- [ ] Page renders correctly on svelte.dev

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .github/workflows/ci.yml                      |   2 +
 .gitignore                                    |   1 +
 .../.generated/browser-support-features.md    |   7 +
 .../07-misc/.generated/browser-support.md     |  13 +
 .../docs/07-misc/05-browser-support.md        |  30 +
 eslint.config.js                              |   1 +
 packages/svelte/package.json                  |   5 +-
 .../scripts/browser-support.detector.js       | 417 +++++++++
 .../scripts/generate-browser-support.ts       | 874 ++++++++++++++++++
 packages/svelte/src/utils.js                  |   2 +-
 pnpm-lock.yaml                                |  31 +-
 11 files changed, 1378 insertions(+), 5 deletions(-)
 create mode 100644 documentation/docs/07-misc/.generated/browser-support-features.md
 create mode 100644 documentation/docs/07-misc/.generated/browser-support.md
 create mode 100644 documentation/docs/07-misc/05-browser-support.md
 create mode 100644 packages/svelte/scripts/browser-support.detector.js
 create mode 100644 packages/svelte/scripts/generate-browser-support.ts

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index df9f755874..4f72b6c23e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -98,6 +98,8 @@ jobs:
       - name: build and check generated types
         if: (${{ success() }} || ${{ failure() }}) # ensures this step runs even if previous steps fail
         run: pnpm build && { [ "`git status --porcelain=v1`" == "" ] || (echo "Generated types have changed — please regenerate types locally with `cd packages/svelte && pnpm generate:types` and commit the changes after you have reviewed them"; git diff; exit 1); }
+      - name: check browser-support docs page is up to date
+        run: '{ [ "`git status --porcelain=v1 documentation/docs/07-misc/05-browser-support.md`" == "" ] || (echo "The browser-support docs page is out of date — please regenerate it locally with \`cd packages/svelte && pnpm generate:browser-support\` and commit the changes"; git diff documentation/docs/07-misc/05-browser-support.md; exit 1); }'
   Benchmarks:
     permissions: {}
     runs-on: ubuntu-latest
diff --git a/.gitignore b/.gitignore
index d3c1819bd5..556cae6344 100644
--- a/.gitignore
+++ b/.gitignore
@@ -22,6 +22,7 @@ coverage
 .DS_Store
 
 tmp
+packages/svelte/scripts/_baseline/
 
 benchmarking/.profiles
 benchmarking/compare/.results
diff --git a/documentation/docs/07-misc/.generated/browser-support-features.md b/documentation/docs/07-misc/.generated/browser-support-features.md
new file mode 100644
index 0000000000..1e1a00d4d3
--- /dev/null
+++ b/documentation/docs/07-misc/.generated/browser-support-features.md
@@ -0,0 +1,7 @@
+<!-- generated in ../../../../../packages/svelte/scripts/generate-browser-support.ts. do not edit -->
+
+| Feature | Chrome/Edge | Firefox | Safari |
+| --- | ---: | ---: | ---: |
+| `$state.snapshot` | 98 | 94 | 15.4 |
+| `bind:devicePixelContentBoxSize` | <span style="color: var(--sk-fg-4)">—</span> | 93 | not supported |
+| `flip` from `svelte/animate` | <span style="color: var(--sk-fg-4)">—</span> | 126 | <span style="color: var(--sk-fg-4)">—</span> |
\ No newline at end of file
diff --git a/documentation/docs/07-misc/.generated/browser-support.md b/documentation/docs/07-misc/.generated/browser-support.md
new file mode 100644
index 0000000000..8c58588960
--- /dev/null
+++ b/documentation/docs/07-misc/.generated/browser-support.md
@@ -0,0 +1,13 @@
+<!-- generated in ../../../../../packages/svelte/scripts/generate-browser-support.ts. do not edit -->
+
+| Browser          | Minimum version |
+| ---------------- | --------------- |
+| Chrome/Edge      | 87              |
+| Firefox          | 83              |
+| Safari           | 14              |
+| Opera            | 73              |
+| Opera (Android)  | 62              |
+| Samsung Internet | 14.0            |
+| Android WebView  | 87              |
+
+> [!NOTE] This equates to a <a href="https://web-platform-dx.github.io/baseline/">Baseline</a> target of 2020.
\ No newline at end of file
diff --git a/documentation/docs/07-misc/05-browser-support.md b/documentation/docs/07-misc/05-browser-support.md
new file mode 100644
index 0000000000..1a8830bdb9
--- /dev/null
+++ b/documentation/docs/07-misc/05-browser-support.md
@@ -0,0 +1,30 @@
+---
+title: Browser support
+---
+
+The table below shows the minimum browser versions Svelte's runtime and compiled output are expected to work in.
+
+@include .generated/browser-support.md
+
+These numbers describe what Svelte's output _requires_ in order to run — they're derived from the APIs the code uses, not from a list of browsers the team commits to testing.
+
+## What is covered
+
+- **Svelte's runtime.** Everything you import from `svelte` or its subpackages, in the form your bundler ships to the browser.
+- **Compiler output.** The JavaScript the Svelte compiler emits from your `.svelte` files, including the DOM operations, bindings and transitions used in your components.
+
+## What is not covered
+
+- **Your own code** inside `<script>` blocks or `.svelte.js` files. If you use newer browser APIs the table will not reflect them — configure your own [browserslist](https://github.com/browserslist/browserslist) and polyfills accordingly.
+- **SvelteKit**, adapters and build tooling. See the [SvelteKit docs](https://svelte.dev/docs/kit) for the browser support story there.
+- **Internet Explorer 11.** Svelte's runtime relies on `Proxy`, which cannot be polyfilled. IE11 is not supported and there is no path to making it work.
+
+## Per-feature browser requirements
+
+Some Svelte features rely on browser APIs that exceed the floor above. The runtime still loads on older browsers — modern bundlers tree-shake the affected code when the feature is unused — but if you use one of these features, you need the higher minimum version listed here.
+
+@include .generated/browser-support-features.md
+
+## How this page stays accurate
+
+The minimum versions can only move forward in a minor or major release, and any change is recorded in the [changelog](https://github.com/sveltejs/svelte/blob/main/packages/svelte/CHANGELOG.md). Every Svelte feature — bindings, runes, directives, and module exports — is checked against the [web-features](https://www.npmjs.com/package/web-features) Baseline dataset on every pull request, and the build fails if a change requires newer browsers than the page reflects.
diff --git a/eslint.config.js b/eslint.config.js
index 0e8382427b..c573ce8fba 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -90,6 +90,7 @@ export default [
 			'**/tests',
 			'packages/svelte/scripts/process-messages/templates/*.js',
 			'packages/svelte/scripts/_bundle.js',
+			'packages/svelte/scripts/_baseline/**',
 			'packages/svelte/src/compiler/errors.js',
 			'packages/svelte/src/internal/client/errors.js',
 			'packages/svelte/src/internal/client/warnings.js',
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index bd10bf5966..5e3bb5e031 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -143,9 +143,10 @@
     "check": "tsc --project tsconfig.runtime.json && tsc && cd ./tests/types && tsc",
     "check:tsgo": "tsgo --project tsconfig.runtime.json --skipLibCheck && tsgo --skipLibCheck",
     "check:watch": "tsc --watch",
-    "generate": "node scripts/process-messages && node ./scripts/generate-types.js",
+    "generate": "node scripts/process-messages && node ./scripts/generate-types.js && pnpm generate:browser-support",
     "generate:version": "node ./scripts/generate-version.js",
     "generate:types": "node ./scripts/generate-types.js && tsc -p tsconfig.generated.json",
+    "generate:browser-support": "node ./scripts/generate-browser-support.ts",
     "prepublishOnly": "pnpm build",
     "knip": "pnpm dlx knip"
   },
@@ -158,8 +159,10 @@
     "@rollup/plugin-virtual": "^3.0.2",
     "@types/aria-query": "^5.0.4",
     "@types/node": "^20.11.5",
+    "baseline-browser-mapping": "^2.10.32",
     "dts-buddy": "^0.5.5",
     "esbuild": "^0.25.10",
+    "web-features": "^3.29.0",
     "rollup": "^4.59.0",
     "source-map": "^0.7.4",
     "tinyglobby": "^0.2.12",
diff --git a/packages/svelte/scripts/browser-support.detector.js b/packages/svelte/scripts/browser-support.detector.js
new file mode 100644
index 0000000000..17cdfc55f7
--- /dev/null
+++ b/packages/svelte/scripts/browser-support.detector.js
@@ -0,0 +1,417 @@
+import ts from 'typescript';
+import { features } from 'web-features';
+
+/**
+ * Maps compat-key suffixes under `javascript.operators` and
+ * `javascript.statements` (and a few other `javascript.*` subtrees) to
+ * detection callbacks. The callback receives a TS AST node and returns
+ * true if that node represents the operator or statement.
+ *
+ * @type {Record<string, (node: ts.Node) => boolean>}
+ */
+const SYNTAX_PREDICATES = {
+	nullish_coalescing: (node) =>
+		ts.isBinaryExpression(node) && node.operatorToken.kind === ts.SyntaxKind.QuestionQuestionToken,
+	nullish_coalescing_assignment: (node) =>
+		ts.isBinaryExpression(node) &&
+		node.operatorToken.kind === ts.SyntaxKind.QuestionQuestionEqualsToken,
+	logical_or_assignment: (node) =>
+		ts.isBinaryExpression(node) && node.operatorToken.kind === ts.SyntaxKind.BarBarEqualsToken,
+	logical_and_assignment: (node) =>
+		ts.isBinaryExpression(node) &&
+		node.operatorToken.kind === ts.SyntaxKind.AmpersandAmpersandEqualsToken,
+	optional_chaining: (node) =>
+		(ts.isPropertyAccessExpression(node) ||
+			ts.isElementAccessExpression(node) ||
+			ts.isCallExpression(node)) &&
+		node.questionDotToken !== undefined,
+	spread: (node) => ts.isSpreadElement(node) || ts.isSpreadAssignment(node),
+	destructuring: (node) => ts.isObjectBindingPattern(node) || ts.isArrayBindingPattern(node),
+	arrow_functions: (node) => ts.isArrowFunction(node),
+	try_catch_optional_binding: (node) =>
+		ts.isCatchClause(node) && node.variableDeclaration === undefined,
+	async_iteration: (node) => ts.isForOfStatement(node) && node.awaitModifier !== undefined,
+	for_await: (node) => ts.isForOfStatement(node) && node.awaitModifier !== undefined,
+	private_class_fields: (node) => ts.isPrivateIdentifier(node),
+	async_generator_function: (node) =>
+		(ts.isFunctionDeclaration(node) ||
+			ts.isFunctionExpression(node) ||
+			ts.isMethodDeclaration(node)) &&
+		node.asteriskToken !== undefined &&
+		(node.modifiers?.some((m) => m.kind === ts.SyntaxKind.AsyncKeyword) ?? false),
+	generator_function: (node) =>
+		(ts.isFunctionDeclaration(node) ||
+			ts.isFunctionExpression(node) ||
+			ts.isMethodDeclaration(node)) &&
+		node.asteriskToken !== undefined &&
+		!(node.modifiers?.some((m) => m.kind === ts.SyntaxKind.AsyncKeyword) ?? false),
+	async_function: (node) =>
+		(ts.isFunctionDeclaration(node) ||
+			ts.isFunctionExpression(node) ||
+			ts.isArrowFunction(node) ||
+			ts.isMethodDeclaration(node)) &&
+		(node.modifiers?.some((m) => m.kind === ts.SyntaxKind.AsyncKeyword) ?? false) &&
+		node.asteriskToken === undefined,
+	classes: (node) => ts.isClassDeclaration(node) || ts.isClassExpression(node),
+	let_const: (node) =>
+		ts.isVariableDeclarationList(node) &&
+		((node.flags & ts.NodeFlags.Let) !== 0 || (node.flags & ts.NodeFlags.Const) !== 0),
+	template_literals: (node) =>
+		ts.isTemplateExpression(node) || ts.isNoSubstitutionTemplateLiteral(node)
+};
+
+/**
+ * Walk `web-features` once and partition every `compat_features` path
+ * into the lookup tables the AST walker uses.
+ */
+function build_detection_maps() {
+	/** @type {Map<string, string>} identifier name → feature_id */
+	const globals = new Map();
+	/** @type {Map<string, Map<string, string>>} type → member → feature_id */
+	const members = new Map();
+	/** @type {Map<string, string>} string-literal value → feature_id */
+	const string_literals = new Map();
+	/** @type {Array<{ predicate: (n: ts.Node) => boolean, feature_id: string }>} */
+	const syntax_predicates = [];
+
+	const add_member = (
+		/** @type {string} */ type,
+		/** @type {string} */ member,
+		/** @type {string} */ feature_id
+	) => {
+		let by_member = members.get(type);
+		if (!by_member) {
+			by_member = new Map();
+			members.set(type, by_member);
+		}
+		// Only set if not already present — the first feature claiming a
+		// (type, member) pair wins. (Multiple features can map to the same
+		// pair via duplicated compat paths; we just need any.)
+		if (!by_member.has(member)) by_member.set(member, feature_id);
+	};
+
+	for (const [feature_id, feature] of Object.entries(features)) {
+		if (!('compat_features' in feature) || !feature.compat_features) continue;
+		for (const path of feature.compat_features) {
+			const parts = path.split('.');
+
+			// `api.X` → global identifier (constructor or function), e.g.
+			// `api.ResizeObserver`, `api.structuredClone`.
+			if (parts[0] === 'api' && parts.length === 2) {
+				globals.set(parts[1], feature_id);
+				continue;
+			}
+
+			// `api.X.Y` → member access on type X. E.g.
+			// `api.HTMLElement.inert`, `api.ResizeObserverEntry.contentBoxSize`.
+			if (parts[0] === 'api' && parts.length === 3) {
+				add_member(parts[1], parts[2], feature_id);
+				continue;
+			}
+
+			// `javascript.builtins.X` → global like Promise, Symbol, Proxy.
+			if (parts[0] === 'javascript' && parts[1] === 'builtins' && parts.length === 3) {
+				globals.set(parts[2], feature_id);
+				continue;
+			}
+
+			// `javascript.builtins.X.Y` → method/property on type X.
+			// We also accept the `ArrayConstructor`-style mapping for static
+			// methods: when the AST walker sees `Array.from(...)`, the
+			// receiver type's symbol name is `ArrayConstructor`, not `Array`.
+			if (parts[0] === 'javascript' && parts[1] === 'builtins' && parts.length === 4) {
+				add_member(parts[2], parts[3], feature_id);
+				add_member(`${parts[2]}Constructor`, parts[3], feature_id);
+				continue;
+			}
+
+			// `javascript.*` syntax: try the second segment first (covers
+			// `javascript.operators.X` and `javascript.statements.X`), then
+			// the last segment (covers `javascript.classes.private_class_fields`
+			// and similar).
+			if (parts[0] === 'javascript' && parts.length >= 3) {
+				const candidates = [parts[2], parts[parts.length - 1]];
+				for (const key of candidates) {
+					if (Object.hasOwn(SYNTAX_PREDICATES, key)) {
+						syntax_predicates.push({ predicate: SYNTAX_PREDICATES[key], feature_id });
+						break;
+					}
+				}
+				continue;
+			}
+		}
+	}
+
+	return { globals, members, string_literals, syntax_predicates };
+}
+
+const MAPS = build_detection_maps();
+
+/**
+ * Versions and friendly names for synthetic feature IDs registered via
+ * `register_extra_rules` — APIs the type-aware walker can see but that
+ * `web-features` doesn't (yet) catalogue. `versions_for_feature` consults
+ * this map before falling back to `web-features` lookups.
+ *
+ * @type {Map<string, { name: string, versions: Record<string, string | null>, baseline_year: number | null }>}
+ */
+const EXTRA_FEATURE_INFO = new Map();
+
+/**
+ * Register additional detection rules for APIs the `web-features` dataset
+ * doesn't track yet. Two rule shapes are accepted:
+ *
+ *   - **Member access**: `{ receiver_type, member, ... }` — flags
+ *     `expr.member` when `expr`'s type resolves to `receiver_type`.
+ *     Equivalent to a `api.X.Y` rule auto-derived from web-features.
+ *
+ *   - **String literal**: `{ string_literal, ... }` — flags any
+ *     occurrence of the literal value in source. Used for API options
+ *     that are string-typed (e.g. `{ box: 'device-pixel-content-box' }`).
+ *     The walker can be tightened later with a contextual-type check if
+ *     false positives ever surface; for now an exact match is enough
+ *     (these strings are too specific to occur incidentally).
+ *
+ * Each rule contributes its `feature_id`, per-browser versions,
+ * baseline year, and display name to the shared lookup tables.
+ *
+ * @param {Array<{
+ *   feature_id: string,
+ *   name: string,
+ *   baseline_year: number,
+ *   versions: Record<string, string | null>,
+ *   receiver_type?: string,
+ *   member?: string,
+ *   string_literal?: string
+ * }>} rules
+ */
+export function register_extra_rules(rules) {
+	for (const rule of rules) {
+		if (rule.receiver_type && rule.member) {
+			let by_member = MAPS.members.get(rule.receiver_type);
+			if (!by_member) {
+				by_member = new Map();
+				MAPS.members.set(rule.receiver_type, by_member);
+			}
+			// Don't overwrite an existing web-features rule; that's canonical.
+			if (!by_member.has(rule.member)) {
+				by_member.set(rule.member, rule.feature_id);
+			}
+		} else if (rule.string_literal) {
+			if (!MAPS.string_literals.has(rule.string_literal)) {
+				MAPS.string_literals.set(rule.string_literal, rule.feature_id);
+			}
+		}
+		EXTRA_FEATURE_INFO.set(rule.feature_id, {
+			name: rule.name,
+			baseline_year: rule.baseline_year,
+			versions: rule.versions
+		});
+	}
+}
+
+/**
+ * Compile bundle files into a single `ts.Program` so type-checking is
+ * amortised across all of them.
+ *
+ * @param {string[]} files
+ */
+function build_program(files) {
+	const program = ts.createProgram(files, {
+		allowJs: true,
+		checkJs: false,
+		target: ts.ScriptTarget.ESNext,
+		module: ts.ModuleKind.ESNext,
+		moduleResolution: ts.ModuleResolutionKind.Bundler,
+		lib: ['lib.esnext.d.ts', 'lib.dom.d.ts', 'lib.dom.iterable.d.ts'],
+		strict: false,
+		noEmit: true,
+		skipLibCheck: true,
+		isolatedModules: true,
+		noErrorTruncation: true
+	});
+	const checker = program.getTypeChecker();
+	return { program, checker };
+}
+
+/**
+ * Collect the names of a type and its base types so a `member` lookup
+ * keyed on (say) `HTMLElement` matches a receiver typed as
+ * `HTMLDivElement`. Also includes the apparent type to catch primitives
+ * (`'foo'` apparent-types to `String`).
+ *
+ * @param {ts.Type} type
+ * @param {ts.TypeChecker} checker
+ */
+function get_type_names(type, checker) {
+	const names = new Set();
+	const constituents = type.isUnionOrIntersection() ? type.types : [type];
+	for (const t of constituents) {
+		const symbol = t.getSymbol() ?? t.aliasSymbol;
+		if (symbol) names.add(symbol.getName());
+		for (const base of t.getBaseTypes?.() ?? []) {
+			const base_symbol = base.getSymbol() ?? base.aliasSymbol;
+			if (base_symbol) names.add(base_symbol.getName());
+		}
+		const apparent = checker.getApparentType(t);
+		if (apparent && apparent !== t) {
+			const apparent_symbol = apparent.getSymbol() ?? apparent.aliasSymbol;
+			if (apparent_symbol) names.add(apparent_symbol.getName());
+		}
+	}
+	return names;
+}
+
+/**
+ * Cheap test for whether a symbol refers to a global binding (declared
+ * in a lib.d.ts or ambient module) rather than a user-defined local.
+ *
+ * @param {ts.Symbol | undefined} symbol
+ */
+function is_global_binding(symbol) {
+	if (!symbol) return true; // unresolved → assume global
+	const declarations = symbol.getDeclarations() ?? [];
+	if (declarations.length === 0) return true;
+	for (const decl of declarations) {
+		const file_name = decl.getSourceFile().fileName;
+		if (file_name.includes('/lib.') && file_name.endsWith('.d.ts')) return true;
+	}
+	return false;
+}
+
+/**
+ * Walk a TS source file emitting feature IDs as they're discovered.
+ *
+ * @param {ts.SourceFile} source
+ * @param {ts.TypeChecker | null} checker
+ *   When `null`, type-aware checks (member access) are skipped. Used for
+ *   the compiler-output fixtures which are parsed without a Program.
+ * @param {(feature_id: string) => void} emit
+ */
+function walk_source(source, checker, emit) {
+	/** @param {ts.Node} node */
+	function visit(node) {
+		// Syntax predicates run regardless of whether we have a checker.
+		for (const { predicate, feature_id } of MAPS.syntax_predicates) {
+			if (predicate(node)) emit(feature_id);
+		}
+
+		// Global identifier detection.
+		if (
+			ts.isIdentifier(node) &&
+			!(ts.isPropertyAccessExpression(node.parent) && node.parent.name === node) &&
+			!ts.isPropertyAssignment(node.parent) &&
+			!ts.isMethodDeclaration(node.parent) &&
+			!ts.isPropertySignature(node.parent)
+		) {
+			const feature_id = MAPS.globals.get(node.text);
+			if (feature_id) {
+				if (!checker || is_global_binding(checker.getSymbolAtLocation(node))) {
+					emit(feature_id);
+				}
+			}
+		}
+
+		// String-literal detection. The walker matches by value alone;
+		// false positives are theoretically possible but the literal
+		// values we care about (e.g. `'device-pixel-content-box'`) are
+		// distinctive enough that one hasn't been observed.
+		if (ts.isStringLiteral(node) || ts.isNoSubstitutionTemplateLiteral(node)) {
+			const feature_id = MAPS.string_literals.get(node.text);
+			if (feature_id) emit(feature_id);
+		}
+
+		// Member access detection (requires the checker).
+		if (checker && ts.isPropertyAccessExpression(node)) {
+			const member_name = node.name.text;
+			const receiver_type = checker.getTypeAtLocation(node.expression);
+			const type_names = get_type_names(receiver_type, checker);
+			for (const type_name of type_names) {
+				const by_member = MAPS.members.get(type_name);
+				if (!by_member) continue;
+				const feature_id = by_member.get(member_name);
+				if (feature_id) {
+					emit(feature_id);
+					break;
+				}
+			}
+		}
+
+		ts.forEachChild(node, visit);
+	}
+
+	visit(source);
+}
+
+/**
+ * Detect features used in a set of bundle files. Returns the union of
+ * web-features IDs flagged across all files.
+ *
+ * @param {string[]} bundle_files Absolute paths to JS/TS files.
+ * @returns {Set<string>}
+ */
+export function detect_features(bundle_files) {
+	const { program, checker } = build_program(bundle_files);
+	const flagged = new Set();
+	for (const file of bundle_files) {
+		const source = program.getSourceFile(file);
+		if (!source) continue;
+		walk_source(source, checker, (id) => flagged.add(id));
+	}
+	return flagged;
+}
+
+/**
+ * Detect features used in a single in-memory source string. No type
+ * checker (so member-based rules silently skip) — useful for the
+ * compiler-output fixtures, where syntax-level detection is sufficient.
+ *
+ * @param {string} source_text
+ * @returns {Set<string>}
+ */
+export function detect_features_in_text(source_text) {
+	const source = ts.createSourceFile(
+		'fixture.js',
+		source_text,
+		ts.ScriptTarget.ESNext,
+		true,
+		ts.ScriptKind.JS
+	);
+	const flagged = new Set();
+	walk_source(source, null, (id) => flagged.add(id));
+	return flagged;
+}
+
+/**
+ * Per-browser minimum versions for a feature ID. Consults
+ * supplemental rules first (from `register_extra_rules`), then falls
+ * back to `web-features`. Returns null when neither has data.
+ *
+ * @param {string} feature_id
+ */
+export function versions_for_feature(feature_id) {
+	const extra = EXTRA_FEATURE_INFO.get(feature_id);
+	if (extra) return extra.versions;
+	const feature = features[feature_id];
+	if (!feature || !('status' in feature)) return null;
+	return /** @type {Record<string, string> | null} */ (
+		/** @type {unknown} */ (feature.status.support)
+	);
+}
+
+/**
+ * Baseline year for a feature. Returns `null` for features without a
+ * Baseline date (limited availability, supplemental rules without a
+ * year, or absent from the dataset).
+ *
+ * @param {string} feature_id
+ */
+export function baseline_year_for_feature(feature_id) {
+	const extra = EXTRA_FEATURE_INFO.get(feature_id);
+	if (extra) return extra.baseline_year;
+	const feature = features[feature_id];
+	if (!feature || !('status' in feature)) return null;
+	const status = /** @type {{ baseline_low_date?: string }} */ (feature.status);
+	if (!status.baseline_low_date) return null;
+	return Number(status.baseline_low_date.slice(0, 4));
+}
diff --git a/packages/svelte/scripts/generate-browser-support.ts b/packages/svelte/scripts/generate-browser-support.ts
new file mode 100644
index 0000000000..b447ba3bdc
--- /dev/null
+++ b/packages/svelte/scripts/generate-browser-support.ts
@@ -0,0 +1,874 @@
+// Regenerates `documentation/docs/07-misc/05-browser-support.md`.
+//
+// Pipeline:
+//   1. Bundle each runtime entry point with rollup using production export
+//      conditions, then walk the resulting JS with TypeScript's compiler
+//      API + TypeChecker. The walker (see `browser-support.detector.js`)
+//      flags any web-features ID the runtime references.
+//   2. Verify each entry in `BEHAVIORAL_IGNORE` is still flagged by the
+//      detector — if not, the entry can be removed.
+//   3. Enumerate every user-facing feature (each `bind:*`, every public
+//      subpackage export, every rune from the compiler's `RUNES` array,
+//      and the handful of directives that need their own fixtures). For
+//      each: compile, bundle, walk. If the bundle requires browser
+//      versions newer than the runtime floor, emit a row in the
+//      conditional-features table. Blind-spot regexes pick up APIs the
+//      AST walker can't see (string-literal constructor options,
+//      `getComputedStyle(...).zoom` reads).
+//   4. Translate floors into concrete browser versions via `web-features`
+//      data (exact per-feature versions), falling back to
+//      `baseline-browser-mapping` for year-only resolution.
+
+import fs from 'node:fs';
+import path from 'node:path';
+import process from 'node:process';
+import { fileURLToPath } from 'node:url';
+import { rollup, type OutputChunk } from 'rollup';
+import virtual from '@rollup/plugin-virtual';
+import { nodeResolve } from '@rollup/plugin-node-resolve';
+import { getCompatibleVersions } from 'baseline-browser-mapping';
+import {
+	detect_features,
+	detect_features_in_text,
+	versions_for_feature,
+	baseline_year_for_feature,
+	register_extra_rules
+} from './browser-support.detector.js';
+import { binding_properties } from '../src/compiler/phases/bindings.js';
+import { RUNES } from '../src/utils.js';
+import { compile as svelte_compile } from '../src/compiler/index.js';
+
+type BindingProperty = import('../src/compiler/phases/bindings.js').BindingProperty;
+type PackageExport = string | { browser?: string; default?: string };
+type CompilerFixture = { filename: string; code: string };
+type Feature = { name: string; source: string; kind: 'svelte' | 'js' };
+type BrowserVersions = Record<string, string | null>;
+type RuntimeFloor = number | 'newly';
+type ConditionalRow = {
+	name: string;
+	versions: BrowserVersions;
+	baseline_year: RuntimeFloor;
+};
+
+// Supplemental detection rules for APIs `web-features` doesn't track
+// yet. Each rule is checked with full TS type-aware precision — the
+// only reason it lives here instead of being auto-derived is that no
+// compat key in `web-features` covers the API.
+register_extra_rules([
+	{
+		// `getComputedStyle(current).zoom` walk in `svelte/animate`'s
+		// `flip` fallback path. Firefox didn't expose `.zoom` on
+		// `CSSStyleDeclaration` until v126 (May 2024) — pre-126 the read
+		// yields an empty string, breaking the animation math. No entry
+		// for it exists in `web-features` (CSS `zoom` is an IDL accessor
+		// without its own Baseline feature record).
+		receiver_type: 'CSSStyleDeclaration',
+		member: 'zoom',
+		feature_id: 'extra:css-zoom-read',
+		name: 'CSS zoom property reads (getComputedStyle(...).zoom)',
+		baseline_year: 2024,
+		versions: { firefox: '126' }
+	},
+	{
+		// `box: 'device-pixel-content-box'` in `bind_resize_observer`
+		// (size.js). The TS DOM lib declares the option value as part of
+		// the `ResizeObserverBoxOptions` union — we could check the
+		// contextual type, but matching the literal value is enough since
+		// the string is too specific to occur incidentally. Per MDN BCD:
+		//   - constructor option: Chrome 84, Firefox 93, Safari 15.4
+		//   - `ResizeObserverEntry.devicePixelContentBoxSize`: Safari NOT
+		//     SUPPORTED (`version_added: false`)
+		// Safari therefore silently accepts the option from 15.4 onwards
+		// but never exposes the matching entry property, so the binding
+		// reads `undefined` on any Safari.
+		string_literal: 'device-pixel-content-box',
+		feature_id: 'extra:device-pixel-content-box',
+		name: 'ResizeObserver `box: device-pixel-content-box` option + `entry.devicePixelContentBoxSize`',
+		baseline_year: 2023,
+		versions: {
+			chrome: '84',
+			edge: '84',
+			firefox: '93',
+			safari: null,
+			safari_ios: null
+		}
+	}
+]);
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+const pkg_dir = path.resolve(__dirname, '..');
+const repo_root = path.resolve(pkg_dir, '..', '..');
+const docs_dir = path.join(repo_root, 'documentation/docs/07-misc/.generated');
+const snapshot_dir = path.join(pkg_dir, 'tests/snapshot/samples');
+const tmp_dir = path.join(__dirname, '_baseline');
+
+const pkg = JSON.parse(fs.readFileSync(path.join(pkg_dir, 'package.json'), 'utf-8')) as {
+	exports: Record<string, PackageExport>;
+};
+
+/**
+ * Suppressions that should NEVER affect the floor regardless of whether
+ * the runtime currently uses the API. Two reasons an entry belongs here:
+ *
+ *   - The `web-features` dataset misclassifies the API (e.g.
+ *     `devicepixelratio` is marked Baseline `false` because Safari is
+ *     missing from its `support` map, but the property has shipped in
+ *     every Safari for over a decade).
+ *   - Svelte feature-detects the API at runtime with `?.` and degrades
+ *     gracefully when it's unavailable. Example: `trusted-types` in
+ *     `src/internal/client/dom/reconciler.js`.
+ *
+ * These are exempt from the staleness check.
+ */
+const SAFE_TO_IGNORE = new Set(['devicepixelratio', 'trusted-types']);
+
+/**
+ * Suppressions for features that DO live in the runtime but are reached
+ * only via a specific code path documented in the per-feature table on
+ * the docs page. The aggregate scan hides them so the headline floor
+ * reflects "load Svelte and use the basic runtime", not "use every
+ * conditional feature".
+ *
+ * Each entry MUST appear in the conditional-features table. The
+ * staleness check below also verifies the entry is still present in the
+ * runtime — if the detector doesn't flag it, the entry can be removed.
+ */
+const BEHAVIORAL_IGNORE = new Set([
+	'structured-clone',
+	'extra:css-zoom-read',
+	'extra:device-pixel-content-box'
+]);
+
+/** Aggregate ignore set — used for the headline floor. */
+const AGGREGATE_IGNORE = new Set([...SAFE_TO_IGNORE, ...BEHAVIORAL_IGNORE]);
+
+/**
+ * Subpaths in `pkg.exports` whose runtime is Node-only. Can't be derived
+ * from the exports map alone — `./compiler` has a `require:` field that
+ * hints at CJS, but `./server` and `./internal/server` are plain `default`
+ * entries indistinguishable from a browser module.
+ */
+const NODE_ONLY_EXPORTS = new Set(['./compiler', './server', './internal/server']);
+
+/**
+ * Every subpath in `pkg.exports` that ships browser JS. Type-only entries
+ * (`./action`, `./elements`) and the `./package.json` re-export filter out
+ * naturally on the `.js` check; only Node-only subpaths need an explicit
+ * exception, so new browser exports are picked up automatically.
+ */
+function browser_subpaths(): string[] {
+	const subpaths: string[] = [];
+	for (const [subpath, conditions] of Object.entries(pkg.exports)) {
+		if (NODE_ONLY_EXPORTS.has(subpath)) continue;
+		if (typeof conditions !== 'object' || conditions === null) continue;
+		const file = conditions.browser ?? conditions.default;
+		if (typeof file !== 'string' || !file.endsWith('.js')) continue;
+		subpaths.push(subpath);
+	}
+	return subpaths;
+}
+
+/**
+ * `.` → `svelte`, `./animate` → `svelte/animate`, etc.
+ */
+function importee_for(subpath: string): string {
+	return subpath === '.' ? 'svelte' : `svelte${subpath.slice(1)}`;
+}
+
+/**
+ * True if a subpath represents a public, user-facing subpackage whose
+ * named exports should each get their own per-feature fixture. Excludes
+ * the main entry (covered by the aggregate scan), the `./legacy` shim,
+ * and everything under `./internal/`.
+ */
+function is_public_subpackage(subpath: string): boolean {
+	return subpath !== '.' && subpath !== './legacy' && !subpath.startsWith('./internal');
+}
+
+/**
+ * For each public subpackage, dynamically import the module and return
+ * its named exports. Driven entirely by `pkg.exports`, so a new
+ * subpackage is picked up the next time the script runs.
+ */
+async function enumerate_subpackage_exports(): Promise<Record<string, string[]>> {
+	const result: Record<string, string[]> = {};
+	for (const subpath of browser_subpaths()) {
+		if (!is_public_subpackage(subpath)) continue;
+		const module_id = importee_for(subpath);
+		try {
+			const ns = await import(module_id);
+			const names = Object.keys(ns)
+				.filter((k) => k !== 'default')
+				.sort();
+			if (names.length > 0) result[module_id] = names;
+		} catch (err) {
+			const message = err instanceof Error ? err.message : String(err);
+			// eslint-disable-next-line no-console
+			console.warn(`  (could not enumerate ${module_id}: ${message.split('\n')[0]})`);
+		}
+	}
+	return result;
+}
+
+const rune_fixtures: Record<(typeof RUNES)[number], string> = {
+	$state: `<script>let v = $state(0); console.log(v);</script>`,
+	'$state.raw': `<script>let v = $state.raw({}); console.log(v);</script>`,
+	'$state.eager': `<script>let v = $state.eager(0); console.log(v);</script>`,
+	'$state.snapshot': `<script>const v = $state({}); const snap = $state.snapshot(v); console.log(snap);</script>`,
+	$derived: `<script>let a = $state(0); let d = $derived(a + 1); console.log(d);</script>`,
+	'$derived.by': `<script>let a = $state(0); let d = $derived.by(() => a + 1); console.log(d);</script>`,
+	$props: `<script>let { x } = $props(); console.log(x);</script>`,
+	'$props.id': `<script>const id = $props.id(); console.log(id);</script>`,
+	$bindable: `<script>let { v = $bindable() } = $props(); console.log(v);</script>`,
+	$effect: `<script>$effect(() => { console.log('e'); });</script>`,
+	'$effect.pre': `<script>$effect.pre(() => { console.log('p'); });</script>`,
+	'$effect.tracking': `<script>$effect(() => { console.log($effect.tracking()); });</script>`,
+	'$effect.root': `<script>const stop = $effect.root(() => () => {}); stop();</script>`,
+	'$effect.pending': `<script>$effect(() => { console.log($effect.pending()); });</script>`,
+	$inspect: `<script>let v = $state(0); $inspect(v);</script>`,
+	'$inspect().with': `<script>let v = $state(0); $inspect(v).with(() => {});</script>`,
+	'$inspect.trace': `<script>$effect(() => { $inspect.trace(); });</script>`,
+	$host: `<svelte:options customElement="x-y" />\n<script>const h = $host(); console.log(h);</script>`
+};
+
+function rune_fixture(rune: (typeof RUNES)[number]): string {
+	if (!Object.hasOwn(rune_fixtures, rune)) {
+		throw new Error(`Fixture missing for ${rune}`);
+	}
+
+	return rune_fixtures[rune];
+}
+
+/**
+ * Compiled-fixture sources for directives. Bindings are covered by the
+ * `binding_properties` enumeration; transitions, animate, actions, and
+ * `@attach` need explicit fixtures because they require accompanying
+ * imports or surrounding markup.
+ */
+const TESTED_DIRECTIVES = [
+	{
+		name: '`transition:` / `in:` / `out:`',
+		source: `<script>import { fade } from 'svelte/transition'; let show = $state(false);</script>{#if show}<div transition:fade></div>{/if}`
+	},
+	{
+		name: '`animate:`',
+		source: `<script>const flip = () => {}; let items = $state([1,2,3]);</script>{#each items as item (item)}<div animate:flip>{item}</div>{/each}`
+	},
+	{
+		name: '`use:` actions',
+		source: `<script>function action(node){return {destroy(){}}}</script><div use:action></div>`
+	},
+	{
+		name: '`@attach`',
+		source: `<script>const attachment = (node) => () => {};</script><div {@attach attachment}></div>`
+	},
+	{
+		name: '`{@html ...}`',
+		source: `<script>let html = $state('<b>x</b>');</script>{@html html}`
+	},
+	{
+		name: 'Custom elements (`<svelte:options customElement>`)',
+		source: `<svelte:options customElement="my-el" />\n<div></div>`
+	}
+];
+
+/**
+ * Filesystem-safe identifier for an importee like `svelte/internal/client`.
+ */
+function safe_name(importee: string): string {
+	return importee.replace(/[^a-z0-9]+/gi, '_');
+}
+
+/**
+ * Bundle an entry the way users receive it, so we scan the same code the
+ * browser does. Mirrors `check-treeshakeability.js`.
+ *
+ * `entry_code` is virtual module source: typically `export * from
+ * 'svelte/...'` for a runtime entry, or compiled fixture JS for a per-feature
+ * scan. `silent` suppresses rollup's circular-dependency warnings — used for
+ * fixture bundles where they're known and noisy.
+ */
+async function bundle(entry_code: string, options: { silent?: boolean } = {}): Promise<string> {
+	const built = await rollup({
+		input: '__entry__',
+		plugins: [
+			virtual({ __entry__: entry_code }),
+			{
+				name: 'resolve-svelte',
+				resolveId(id: string) {
+					if (id.startsWith('svelte')) {
+						const entry = pkg.exports[id.replace('svelte', '.')];
+						if (!entry) return;
+						if (typeof entry === 'string') return path.resolve(pkg_dir, entry);
+						const file = entry.browser ?? entry.default;
+						if (file) return path.resolve(pkg_dir, file);
+					}
+				}
+			},
+			nodeResolve({ exportConditions: ['production', 'import', 'browser', 'default'] })
+		],
+		// Treat optional peers / Node-only branches as external so we only scan
+		// code that actually runs in the browser.
+		external: ['esm-env'],
+		onwarn: options.silent
+			? () => {}
+			: (warning, handler) => {
+					if (warning.code === 'CIRCULAR_DEPENDENCY') return;
+					handler(warning);
+				}
+	});
+
+	const { output } = await built.generate({ format: 'esm' });
+	await built.close();
+
+	return output
+		.filter((chunk): chunk is OutputChunk => chunk.type === 'chunk')
+		.map((chunk) => chunk.code)
+		.join('\n');
+}
+
+/**
+ * Read every compiler-emitted client file from the snapshot tests. These
+ * fixtures cover the full range of patterns the compiler emits — bindings,
+ * transitions, `<svelte:element>`, async derived, hydration markers, etc.
+ */
+function load_compiler_output_fixtures(): CompilerFixture[] {
+	const fixtures: CompilerFixture[] = [];
+
+	for (const sample of fs.readdirSync(snapshot_dir)) {
+		const client_dir = path.join(snapshot_dir, sample, '_expected/client');
+		if (!fs.existsSync(client_dir)) continue;
+
+		for (const file of fs.readdirSync(client_dir)) {
+			if (!file.endsWith('.js')) continue;
+			fixtures.push({
+				filename: `${sample}/${file}`,
+				code: fs.readFileSync(path.join(client_dir, file), 'utf-8')
+			});
+		}
+	}
+
+	return fixtures;
+}
+
+/**
+ * Combine per-feature version data into a single Record. Takes the max
+ * (strictest) version per browser across the input feature IDs.
+ *
+ * `null` propagates as "not supported" — if any contributing feature
+ * marks a browser unsupported, the merged record does too.
+ *
+ * Returns `null` if NONE of the IDs have versions in `web-features` or
+ * supplemental rules, so callers can fall back to year-based mapping.
+ */
+function versions_from_features(ids: Iterable<string>): BrowserVersions | null {
+	const merged: BrowserVersions = {};
+	let any_found = false;
+
+	for (const id of ids) {
+		const support = versions_for_feature(id);
+		if (!support) continue;
+		any_found = true;
+		for (const [browser, version] of Object.entries(support)) {
+			const current = merged[browser];
+			// `null` means "not supported"; propagate it directly.
+			if (version === null) {
+				merged[browser] = null;
+				continue;
+			}
+			if (current === null) continue; // already known unsupported
+			if (current === undefined || Number(version) > Number(current)) {
+				merged[browser] = version;
+			}
+		}
+	}
+
+	return any_found ? merged : null;
+}
+
+/**
+ * Highest baseline year among `detected`, and the set of feature IDs that
+ * drove it. Used both for the aggregate runtime floor and for per-fixture
+ * scans — the two differ only in their ignore set.
+ */
+function compute_floor(
+	detected: Iterable<string>,
+	ignore: Set<string>
+): { year: number; drivers: Set<string> } {
+	let year = 0;
+	const drivers = new Set<string>();
+	for (const id of detected) {
+		if (ignore.has(id)) continue;
+		const y = baseline_year_for_feature(id);
+		if (!y) continue;
+		if (y > year) {
+			year = y;
+			drivers.clear();
+		}
+		if (y === year) drivers.add(id);
+	}
+	return { year, drivers };
+}
+
+/**
+ * Run the TS-based detector across the runtime bundles and the compiler-
+ * output fixtures, then compute the highest baseline year among the
+ * detected features (after subtracting `AGGREGATE_IGNORE`).
+ *
+ * `runtime_files` are absolute paths to runtime bundle files. Returns the
+ * minimum Baseline year the combined code satisfies.
+ */
+function find_minimum_target(
+	runtime_files: string[],
+	compiler_fixtures: CompilerFixture[]
+): number {
+	// Type-aware walk over the runtime bundles.
+	const detected = detect_features(runtime_files);
+
+	// Syntax-only walk over the compiler-output fixtures (text only, no
+	// program context; the bare TS source-file parser handles the syntax
+	// features the compiler emits).
+	for (const fixture of compiler_fixtures) {
+		for (const id of detect_features_in_text(fixture.code)) detected.add(id);
+	}
+
+	const { year, drivers } = compute_floor(detected, AGGREGATE_IGNORE);
+	// Floor at 2015 so the docs never claim a pre-ES6 target if every
+	// detected feature happens to lack a Baseline year.
+	const final_year = Math.max(year, 2015);
+
+	// eslint-disable-next-line no-console
+	console.log(`  → ${final_year} (features that drove the floor:)`);
+	for (const id of [...drivers].sort()) {
+		// eslint-disable-next-line no-console
+		console.log(`    - ${id}`);
+	}
+
+	return final_year;
+}
+
+/**
+ * Verify every entry in `BEHAVIORAL_IGNORE` is actually used by the
+ * runtime. Without this, a behavioural suppression can outlive the API
+ * it suppresses — the comment stays in the config pointing at code that
+ * no longer exists.
+ *
+ * `SAFE_TO_IGNORE` entries are exempt: they're safe to carry regardless
+ * of whether the runtime currently uses the API.
+ *
+ */
+function validate_ignore_features(runtime_files: string[]): void {
+	if (BEHAVIORAL_IGNORE.size === 0) return;
+	const detected = detect_features(runtime_files);
+	const stale = [...BEHAVIORAL_IGNORE].filter((id) => !detected.has(id));
+	if (stale.length > 0) {
+		throw new Error(
+			`BEHAVIORAL_IGNORE contains entries that the detector does not flag — ` +
+				`they can be removed:\n` +
+				stale.map((id) => `  - ${id}`).join('\n') +
+				`\n\nEdit \`packages/svelte/scripts/generate-browser-support.js\` ` +
+				`and delete the stale entries. If the API was removed from the runtime ` +
+				`as part of this change, that is exactly the intended signal.`
+		);
+	}
+}
+
+/**
+ * Build the full list of user-facing features to test for conditional
+ * floor bumps. Each feature gets a self-contained fixture, compiled and
+ * bundled like real user code, then scanned. If the bundle's floor
+ * exceeds the runtime floor, a row is auto-emitted in the docs.
+ *
+ * `subpackage_exports` maps subpath → list of exported symbols, produced by
+ * `enumerate_subpackage_exports`. Passed in rather than computed here so the
+ * dynamic-import discovery can happen once in `main`.
+ */
+function enumerate_features(subpackage_exports: Record<string, string[]>): Feature[] {
+	const features: Feature[] = [];
+
+	// Every `bind:*` accepted by the compiler. Element selection respects
+	// the `valid_elements` constraint declared in `binding_properties`.
+	for (const [name, props] of Object.entries(binding_properties)) {
+		const fixture = binding_fixture(name, props);
+		if (fixture) {
+			features.push({
+				name: `\`bind:${name}\``,
+				kind: 'svelte',
+				source: fixture
+			});
+		}
+	}
+
+	for (const [module, exports] of Object.entries(subpackage_exports)) {
+		for (const exp of exports) {
+			features.push({
+				name: `\`${exp}\` from \`${module}\``,
+				kind: 'js',
+				source: `import { ${exp} } from '${module}'; export const _ = ${exp};`
+			});
+		}
+	}
+
+	for (const rune of RUNES) {
+		features.push({
+			name: `\`${rune}\``,
+			kind: 'svelte',
+			source: rune_fixture(rune)
+		});
+	}
+
+	for (const directive of TESTED_DIRECTIVES) {
+		features.push({ name: directive.name, kind: 'svelte', source: directive.source });
+	}
+
+	return features;
+}
+
+/**
+ * Produce the `.svelte` source for a single binding fixture. Returns
+ * `null` for bindings the compiler treats as elements rather than
+ * properties (none currently, but defensive).
+ *
+ */
+function binding_fixture(name: string, props: BindingProperty): string {
+	// Map declared `valid_elements` to a concrete element + minimal attrs
+	// so the compiler accepts the binding.
+	const tag = (props.valid_elements ?? ['div'])[0];
+
+	// Pick a sensible initial value and attribute set per binding.
+	const reactive = `let v = $state();`;
+
+	if (tag === 'svelte:window') {
+		return `<script>${reactive}</script><svelte:window bind:${name}={v} />`;
+	}
+	if (tag === 'svelte:document') {
+		return `<script>${reactive}</script><svelte:document bind:${name}={v} />`;
+	}
+	if (tag === 'input') {
+		// `bind:checked` requires type="checkbox"|"radio"; `bind:group` too.
+		const type =
+			name === 'checked' || name === 'indeterminate'
+				? ' type="checkbox"'
+				: name === 'group'
+					? ' type="radio" value="a"'
+					: name === 'files'
+						? ' type="file"'
+						: '';
+		return `<script>${reactive}</script><input${type} bind:${name}={v} />`;
+	}
+	if (tag === 'details') {
+		return `<script>${reactive}</script><details bind:${name}={v}><summary>x</summary></details>`;
+	}
+
+	return `<script>${reactive}</script><${tag} bind:${name}={v}></${tag}>`;
+}
+
+/**
+ * Compile a `.svelte` fixture to JS (no-op for `.js` fixtures), then
+ * bundle the result through the shared `bundle` helper. Fixtures are tiny
+ * so circular-dep warnings from the Svelte runtime are silenced.
+ *
+ */
+async function bundle_fixture(feature: Feature): Promise<string> {
+	const entry_code =
+		feature.kind === 'svelte'
+			? svelte_compile(feature.source, {
+					generate: 'client',
+					filename: 'Fixture.svelte',
+					dev: false
+				}).js.code
+			: feature.source;
+	return bundle(entry_code, { silent: true });
+}
+
+/**
+ * Detect features in a single fixture bundle and report the per-fixture
+ * floor year along with the IDs that drove it. Used for the per-feature
+ * conditional table.
+ *
+ * `fixture_file` is the absolute path to the `.ts` bundle.
+ */
+function scan_fixture(fixture_file: string): {
+	year: number;
+	driving_ids: string[];
+} {
+	const { year, drivers } = compute_floor(detect_features([fixture_file]), SAFE_TO_IGNORE);
+
+	return {
+		year,
+		driving_ids: [...drivers]
+	};
+}
+
+/**
+ * Iterate every feature, bundle its fixture, scan it. Return the rows
+ * that need to appear in the conditional-features table.
+ */
+async function find_all_conditional_features(
+	runtime_floor: RuntimeFloor,
+	subpackage_exports: Record<string, string[]>
+): Promise<ConditionalRow[]> {
+	const runtime_year = typeof runtime_floor === 'number' ? runtime_floor : Infinity;
+	const features = enumerate_features(subpackage_exports);
+	const rows: ConditionalRow[] = [];
+
+	for (let i = 0; i < features.length; i++) {
+		const feature = features[i];
+		process.stdout.write(`\r  ${i + 1}/${features.length}  ${feature.name}`.padEnd(80));
+
+		let bundle_code;
+		try {
+			bundle_code = await bundle_fixture(feature);
+		} catch {
+			continue; // some fixtures (rare element combos) may fail to compile
+		}
+
+		// Write the bundle so the type-aware scanner can resolve its types.
+		const fixture_file = path.join(tmp_dir, `fixture_${i}.ts`);
+		fs.writeFileSync(fixture_file, bundle_code);
+
+		const scanned = scan_fixture(fixture_file);
+		const final_year = scanned.year;
+
+		// Skip features at or below the runtime floor — they don't need a row.
+		if (final_year <= runtime_year || final_year === 0) continue;
+
+		// Use exact per-feature versions where available (from web-features
+		// or supplemental rules), falling back to the conservative year
+		// mapping only if no feature has explicit version data.
+		let versions = versions_from_features(scanned.driving_ids);
+		if (!versions) {
+			try {
+				versions = browser_versions_for(final_year);
+			} catch {
+				continue;
+			}
+		}
+
+		rows.push({
+			name: feature.name,
+			versions,
+			baseline_year: final_year
+		});
+	}
+	process.stdout.write('\n');
+
+	return rows;
+}
+
+/**
+ * Render the per-feature browser-requirements table from the auto-detected
+ * rows. Sorted by Safari floor descending, then alphabetically.
+ */
+function render_conditional_table(rows: ConditionalRow[], runtime_floor: RuntimeFloor): string {
+	if (rows.length === 0) {
+		return '_No features currently require browser versions newer than the runtime floor._';
+	}
+
+	const browsers = [
+		['chrome', 'Chrome/Edge'],
+		['firefox', 'Firefox'],
+		['safari', 'Safari']
+	] as const;
+
+	const runtime_versions = browser_versions_for(runtime_floor);
+
+	const sorted = [...rows].sort((a, b) => {
+		const sa = Number(a.versions.safari ?? '0');
+		const sb = Number(b.versions.safari ?? '0');
+		if (sb !== sa) return sb - sa;
+		return a.name.localeCompare(b.name);
+	});
+
+	const header = '| Feature | ' + browsers.map(([, label]) => `${label}`).join(' | ') + ' |';
+	const sep = '| --- |' + browsers.map(() => ' ---: |').join('');
+
+	const body = sorted.map((entry) => {
+		const cells = browsers.map(([key]) => {
+			const v = entry.versions[key];
+			if (v === null) return 'not supported';
+			if (v === undefined) return '<span style="color: var(--sk-fg-4)">—</span>';
+			const floor_v = runtime_versions[key];
+			return floor_v && Number(v) <= Number(floor_v)
+				? '<span style="color: var(--sk-fg-4)">—</span>'
+				: v;
+		});
+		return `| ${entry.name} | ${cells.join(' | ')} |`;
+	});
+
+	return [header, sep, ...body].join('\n');
+}
+
+function browser_versions_for(target: RuntimeFloor): Record<string, string> {
+	// `targetYear` returns the minimum versions in which every feature that
+	// reached Baseline by the end of that year is supported. If the lint
+	// search fell through to `'newly'`, we use the current year — that gives
+	// the most recent Newly-available cutoff, which is the strongest
+	// statement `baseline-browser-mapping` is able to make.
+	const target_year = typeof target === 'number' ? target : new Date().getFullYear();
+
+	const versions = getCompatibleVersions({
+		targetYear: target_year,
+		includeDownstreamBrowsers: true
+	});
+
+	// The core Baseline browsers plus the downstream browsers worth listing
+	// in the docs. Downstream browsers come from `baseline-browser-mapping`'s
+	// dataset and represent the highest-traffic Chromium derivatives; the
+	// long tail (UC, QQ, Yandex, in-app Facebook/Instagram browsers, etc.)
+	// is omitted to keep the table focused.
+	const visible_browsers = new Set([
+		'chrome',
+		'chrome_android',
+		'edge',
+		'firefox',
+		'firefox_android',
+		'safari',
+		'safari_ios',
+		'opera',
+		'opera_android',
+		'samsunginternet_android',
+		'webview_android'
+	]);
+
+	const suffixes = ['_android', '_ios'];
+
+	const lookup: Record<string, string> = {};
+	outer: for (const { browser, version } of versions) {
+		if (visible_browsers.has(browser)) {
+			for (const suffix of suffixes) {
+				// skip e.g. 'Chrome (Android)' if it matches Chrome
+				if (browser.endsWith(suffix) && version === lookup[browser.replace(suffix, '')]) {
+					continue outer;
+				}
+			}
+
+			lookup[browser] = version;
+		}
+	}
+
+	return lookup;
+}
+
+function render_table(versions: Record<string, string>, target: RuntimeFloor): string {
+	// Chrome and Edge ship from the same engine and historically resolve to the
+	// same Baseline version. Collapse them into one row when they match, but
+	// fall back to listing them separately if they ever drift.
+	const chrome_edge: [string, string] | null =
+		versions.chrome && versions.chrome === versions.edge ? ['Chrome/Edge', versions.chrome] : null;
+
+	const base_rows: Array<[string, string]> = chrome_edge
+		? [chrome_edge, ['Chrome (Android)', versions.chrome_android]]
+		: [
+				['Chrome', versions.chrome],
+				['Chrome (Android)', versions.chrome_android],
+				['Edge', versions.edge]
+			];
+
+	const rows = [
+		...base_rows,
+		['Firefox', versions.firefox],
+		['Firefox (Android)', versions.firefox_android],
+		['Safari', versions.safari],
+		['Safari (iOS)', versions.safari_ios],
+		['Opera', versions.opera],
+		['Opera (Android)', versions.opera_android],
+		['Samsung Internet', versions.samsunginternet_android],
+		['Android WebView', versions.webview_android]
+	].filter(([label, version]) => version !== undefined) as Array<[string, string]>;
+
+	const headings = ['Browser', 'Minimum version'];
+
+	const widths = headings.map((heading, i) =>
+		Math.max(heading.length, ...rows.map((r) => String(r[i]).length))
+	);
+
+	const pad = (s: string, n: number) => s + ' '.repeat(Math.max(0, n - s.length));
+
+	const header = `| ${headings.map((heading, i) => pad(heading, widths[i])).join(' | ')} |`;
+	const sep = `| ${widths.map((width) => '-'.repeat(width)).join(' | ')} |`;
+	const body = rows
+		.map(([a, b]) => `| ${pad(a, widths[0])} | ${pad(String(b), widths[1])} |`)
+		.join('\n');
+
+	const target_label = target === 'newly' ? '"newly available"' : target;
+
+	return `${header}\n${sep}\n${body}\n\n> [!NOTE] This equates to a <a href="https://web-platform-dx.github.io/baseline/">Baseline</a> target of ${target_label}.`;
+}
+
+/* eslint-disable no-console */
+async function main() {
+	console.log('Preparing scratch directory…');
+	// Wipe and recreate so stale bundles can't leak into the next scan.
+	fs.rmSync(tmp_dir, { recursive: true, force: true });
+	fs.mkdirSync(tmp_dir, { recursive: true });
+
+	try {
+		console.log('Bundling runtime entries…');
+		const runtime_files: string[] = [];
+		for (const importee of browser_subpaths().map(importee_for)) {
+			// `import * as` + re-export keeps default and named exports
+			// alive, so flag modules (only a default export) don't produce
+			// empty chunks but their code still ends up in the scan.
+			const code = await bundle(`import * as __ns from '${importee}'; export default __ns;`);
+			const file = path.join(tmp_dir, `${safe_name(importee)}.ts`);
+			fs.writeFileSync(file, code);
+			runtime_files.push(file);
+		}
+
+		console.log('Loading compiler-output fixtures…');
+		const compiler_fixtures = load_compiler_output_fixtures();
+		console.log(`  (${compiler_fixtures.length} fixtures found)`);
+
+		console.log('Searching for the minimum Baseline target (type-aware)…');
+		const target = find_minimum_target(runtime_files, compiler_fixtures);
+
+		console.log('Checking BEHAVIORAL_IGNORE for stale entries…');
+		validate_ignore_features(runtime_files);
+		console.log('  no stale entries');
+
+		console.log('Enumerating subpackage exports…');
+		const subpackage_exports = await enumerate_subpackage_exports();
+		const total_exports = Object.values(subpackage_exports).reduce((n, list) => n + list.length, 0);
+		console.log(
+			`  ${total_exports} export(s) across ${Object.keys(subpackage_exports).length} subpackage(s)`
+		);
+
+		console.log('Scanning per-feature fixtures for conditional requirements…');
+		const conditional_rows = await find_all_conditional_features(target, subpackage_exports);
+		console.log(
+			`  ${conditional_rows.length} feature(s) require browsers newer than the runtime floor`
+		);
+
+		console.log('Resolving browser versions…');
+		const versions = browser_versions_for(target);
+
+		console.log('Rewriting docs page…');
+		generate('browser-support.md', render_table(versions, target));
+		generate('browser-support-features.md', render_conditional_table(conditional_rows, target));
+
+		console.log('Done.');
+	} finally {
+		// Ensure cleanup happens even on failure — otherwise leftover bundle
+		// files in `scripts/_baseline/` get picked up by `pnpm lint` on the
+		// next CI step and produce spurious naming/no-console errors.
+		fs.rmSync(tmp_dir, { recursive: true, force: true });
+	}
+}
+
+function generate(file: string, content: string): void {
+	const filename = path.join(docs_dir, file);
+
+	try {
+		fs.mkdirSync(path.dirname(file), { recursive: true });
+	} catch {}
+
+	const backlink = path.relative(filename, fileURLToPath(import.meta.url));
+
+	fs.writeFileSync(filename, `<!-- generated in ${backlink}. do not edit -->\n\n${content}`);
+}
+
+main().catch((err) => {
+	console.error(err);
+	process.exit(1);
+});
diff --git a/packages/svelte/src/utils.js b/packages/svelte/src/utils.js
index 54757a6f13..40b558d0f9 100644
--- a/packages/svelte/src/utils.js
+++ b/packages/svelte/src/utils.js
@@ -434,7 +434,7 @@ const STATE_CREATION_RUNES = /** @type {const} */ ([
 	'$derived.by'
 ]);
 
-const RUNES = /** @type {const} */ ([
+export const RUNES = /** @type {const} */ ([
 	...STATE_CREATION_RUNES,
 	'$state.eager',
 	'$state.snapshot',
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 25899b297d..4c077f0f6b 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -103,7 +103,7 @@ importers:
         version: 1.2.1
       esrap:
         specifier: ^2.2.9
-        version: 2.2.9(@typescript-eslint/types@8.56.0)
+        version: 2.2.9(@typescript-eslint/types@8.59.4)
       is-reference:
         specifier: ^3.0.3
         version: 3.0.3
@@ -141,6 +141,9 @@ importers:
       '@types/node':
         specifier: ^20.11.5
         version: 20.19.17
+      baseline-browser-mapping:
+        specifier: ^2.10.32
+        version: 2.10.32
       dts-buddy:
         specifier: ^0.5.5
         version: 0.5.5(typescript@5.5.4)
@@ -162,6 +165,9 @@ importers:
       vitest:
         specifier: ^2.1.9
         version: 2.1.9(@types/node@20.19.17)(jsdom@25.0.1)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+      web-features:
+        specifier: ^3.29.0
+        version: 3.29.0
 
   playgrounds/sandbox:
     devDependencies:
@@ -1153,6 +1159,10 @@ packages:
     resolution: {integrity: sha512-DBsLPs3GsWhX5HylbP9HNG15U0bnwut55Lx12bHB9MpXxQ+R5GC8MwQe+N1UFXxAeQDvEsEDY6ZYwX03K7Z6HQ==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
 
+  '@typescript-eslint/types@8.59.4':
+    resolution: {integrity: sha512-F1o7WJcCq+bc8dwcO/YsSEOudAH8RDtaOhM6wcAQhcUsFhnWQl81JKy48q1hoxAU0qrzM89+31GYh1515Zde3Q==}
+    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+
   '@typescript-eslint/typescript-estree@8.56.0':
     resolution: {integrity: sha512-ex1nTUMWrseMltXUHmR2GAQ4d+WjkZCT4f+4bVsps8QEdh0vlBsaCokKTPlnqBFqqGaxilDNJG7b8dolW2m43Q==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
@@ -1281,6 +1291,11 @@ packages:
   balanced-match@1.0.2:
     resolution: {integrity: sha512-3oSeUO0TMV67hN1AmbXsK4yaqU7tjiHlbxRDZOpH0KW9+CeX4bRAaX0Anxt0tx2MrpRpWwQaPwIlISEJhYU5Pw==}
 
+  baseline-browser-mapping@2.10.32:
+    resolution: {integrity: sha512-wbPvpyjJPC0zdfdKXxqEL3Ea+bOMD/87X4lftiJkkaBiuG6ALQy1SLmEd7BSmVCuwCQsBrCamgBoLyfFDD1EPg==}
+    engines: {node: '>=6.0.0'}
+    hasBin: true
+
   better-path-resolve@1.0.0:
     resolution: {integrity: sha512-pbnl5XzGBdrFU/wT4jqmJVPn2B6UHPBOhzMQkY/SPUPB6QtUXtmBHBIwCbXJol93mOpGMnQyP/+BB19q04xj7g==}
     engines: {node: '>=4'}
@@ -2660,6 +2675,9 @@ packages:
     resolution: {integrity: sha512-o8qghlI8NZHU1lLPrpi2+Uq7abh4GGPpYANlalzWxyWteJOCsr/P+oPBA49TOLu5FTZO4d3F9MnWJfiMo4BkmA==}
     engines: {node: '>=18'}
 
+  web-features@3.29.0:
+    resolution: {integrity: sha512-r8m0Xj77/PSHXEbv2U3UuLhw5gE4U+YAPek5hCor5DMsS9Qnwtxl5FSfam3dXQo7Gl0gxK9BRrcQLlOBZZZXpw==}
+
   webidl-conversions@3.0.1:
     resolution: {integrity: sha512-2JAn3z8AR6rjK8Sm8orRC0h/bcl/DqL7tRPdGZ4I1CjdF+EaMLmYxBHyXuKL849eucPFhvBoxMsflfOb8kxaeQ==}
 
@@ -3530,6 +3548,9 @@ snapshots:
 
   '@typescript-eslint/types@8.56.0': {}
 
+  '@typescript-eslint/types@8.59.4':
+    optional: true
+
   '@typescript-eslint/typescript-estree@8.56.0(typescript@5.5.4)':
     dependencies:
       '@typescript-eslint/project-service': 8.56.0(typescript@5.5.4)
@@ -3676,6 +3697,8 @@ snapshots:
 
   balanced-match@1.0.2: {}
 
+  baseline-browser-mapping@2.10.32: {}
+
   better-path-resolve@1.0.0:
     dependencies:
       is-windows: 1.0.2
@@ -4051,11 +4074,11 @@ snapshots:
     dependencies:
       estraverse: 5.3.0
 
-  esrap@2.2.9(@typescript-eslint/types@8.56.0):
+  esrap@2.2.9(@typescript-eslint/types@8.59.4):
     dependencies:
       '@jridgewell/sourcemap-codec': 1.5.0
     optionalDependencies:
-      '@typescript-eslint/types': 8.56.0
+      '@typescript-eslint/types': 8.59.4
 
   esrecurse@4.3.0:
     dependencies:
@@ -5036,6 +5059,8 @@ snapshots:
     dependencies:
       xml-name-validator: 5.0.0
 
+  web-features@3.29.0: {}
+
   webidl-conversions@3.0.1: {}
 
   webidl-conversions@7.0.0: {}

From a9916053d9bbad77143d34dd7fdd5ed8b2394413 Mon Sep 17 00:00:00 2001
From: Mathias Picker <48158184+MathiasWP@users.noreply.github.com>
Date: Thu, 28 May 2026 21:08:42 +0200
Subject: [PATCH 050/222] perf: use createElement instead of createElementNS
 for HTML elements (#18262)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

## Summary

The current wrapper always calls `document.createElementNS(namespace ??
NAMESPACE_HTML, tag, options)` — even for HTML elements (the >99% case),
and even when `options` would be `undefined`. Two effects compound:

1. **Route HTML elements through `createElement`** — Blink has a fast
path that skips the namespace lookup `createElementNS` always performs.
2. **Omit the trailing `undefined` argument** — V8/Blink take a slower
path for `createElementNS(ns, tag, undefined)` (and `createElement(tag,
undefined)`) than for the bare 2-arg form. This applies symmetrically to
the SVG/MathML branch, where the wrapper now also avoids the `undefined`
3rd arg.

The wrapper dispatches to the fastest call shape for every input —
`{HTML, non-HTML}` × `{with is, without is}` × no `undefined` ever.

## Affects

Every place Svelte constructs a DOM element internally:
`<svelte:element>`, `run_scripts`, the per-component `<style>` injector,
the `{@html}` wrapper, and the `<template>` element used to clone string
templates.

## Numbers

Measured in headless Chromium (Chromium 145) using the browser bench
harness from #18261, 2–3 runs, median. Lower per-call is better; higher
hz is better.

### Raw call shapes (what each shape costs in the browser)

|                                             |       hz | per-call |
| ------------------------------------------- | -------: | -------: |
| `createElement(tag)`                        |  ~1,210k | ~0.83 µs |
| `createElement(tag, undefined)`             |    ~901k | ~1.11 µs |
| `createElementNS(NS_HTML, tag)`             |    ~913k | ~1.10 µs |
| `createElementNS(NS_HTML, tag, undefined)`  |    ~630k | ~1.59 µs |
| `createElement(tag, { is })`                |    ~484k | ~2.07 µs |
| `createElementNS(SVG_NS, tag)`              |    ~333k | ~3.01 µs |
| `createElementNS(SVG_NS, tag, undefined)`   |    ~303k | ~3.30 µs |
| `createElementNS(SVG_NS, tag, { is })`      |    ~245k | ~4.08 µs |

Two stable effects fall out:

- **Trailing `undefined` is consistently slower** than the bare form —
~26% on `createElement`, ~31% on `createElementNS` (HTML), ~10% on
`createElementNS` (SVG).
- **`createElement` skips a namespace lookup** that `createElementNS`
always performs — ~32% delta for equal-shape calls (`createElement(tag)`
vs `createElementNS(NS_HTML, tag)`).

### Per-case impact of this PR

| Case (namespace, `is`) | Old wrapper call | Old hz | New wrapper call
| New hz | Speedup |
| ----------------------------- |
--------------------------------------------- | --------: |
------------------------------ | --------: | ------: |
| HTML, no `is` (dominant path) | `createElementNS(NS_HTML, tag,
undefined)` | ~630k | `createElement(tag)` | ~1,210k | **~92%** (1.92×)
|
| HTML, with `is` | `createElementNS(NS_HTML, tag, { is })` | (slow) |
`createElement(tag, { is })` | ~484k | similar to above (just the
NS-skip) |
| SVG/MathML, no `is` | `createElementNS(ns, tag, undefined)` | ~303k |
`createElementNS(ns, tag)` | ~333k | **~10%** |
| SVG/MathML, with `is` | `createElementNS(ns, tag, { is })` | ~245k |
same | ~245k | no change |

No measurable change in JSDOM (both shapes route through the same JS
implementation there).

The headline gain — **~92% on the dominant HTML-no-`is` path** —
combines both effects roughly equally: dropping the `undefined` (~46%)
and switching to `createElement` (~32%).

Wrapper-vs-raw was also verified: the new wrapper measured to within ±2%
of raw `document.createElement(tag)` for the HTML-no-`is` case, so the
function-call indirection adds no measurable overhead.

See #18261 for the benchmark and methodology.

## Test plan

- [x] All 5881 runtime tests still pass (runtime-runes + runtime-legacy)
- [x] `<svelte:element xmlns={null}>` correctly falls back to HTML
(covered by existing `dynamic-element-dynamic-namespace` test)
- [x] SVG/MathML namespaces still go through `createElementNS`
- [x] Custom-element `is` option still honoured on both branches

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 .changeset/create-element-fast-path.md             |  5 +++++
 .../svelte/src/internal/client/dom/operations.js   | 14 ++++++++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/create-element-fast-path.md

diff --git a/.changeset/create-element-fast-path.md b/.changeset/create-element-fast-path.md
new file mode 100644
index 0000000000..8b88a14163
--- /dev/null
+++ b/.changeset/create-element-fast-path.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+perf: use `createElement` instead of `createElementNS` for HTML elements
diff --git a/packages/svelte/src/internal/client/dom/operations.js b/packages/svelte/src/internal/client/dom/operations.js
index f6d05162ca..bc12a0b07e 100644
--- a/packages/svelte/src/internal/client/dom/operations.js
+++ b/packages/svelte/src/internal/client/dom/operations.js
@@ -233,6 +233,12 @@ export function should_defer_append() {
 }
 
 /**
+ * Branching here is intentional and load-bearing for perf. `createElement(tag)`
+ * hits a fast path in Blink that `createElementNS(NAMESPACE_HTML, tag)` doesn't,
+ * and passing an explicit `undefined` as the trailing options arg measurably
+ * slows both APIs. Funnelling every case through a single `createElementNS(ns,
+ * tag, options)` call would be smaller but slower on the HTML path.
+ *
  * @template {keyof HTMLElementTagNameMap | string} T
  * @param {T} tag
  * @param {string} [namespace]
@@ -240,9 +246,13 @@ export function should_defer_append() {
  * @returns {T extends keyof HTMLElementTagNameMap ? HTMLElementTagNameMap[T] : Element}
  */
 export function create_element(tag, namespace, is) {
-	let options = is ? { is } : undefined;
+	if (namespace == null || namespace === NAMESPACE_HTML) {
+		return /** @type {T extends keyof HTMLElementTagNameMap ? HTMLElementTagNameMap[T] : Element} */ (
+			is ? document.createElement(tag, { is }) : document.createElement(tag)
+		);
+	}
 	return /** @type {T extends keyof HTMLElementTagNameMap ? HTMLElementTagNameMap[T] : Element} */ (
-		document.createElementNS(namespace ?? NAMESPACE_HTML, tag, options)
+		is ? document.createElementNS(namespace, tag, { is }) : document.createElementNS(namespace, tag)
 	);
 }
 

From a9e82dd388815bdd3c86bec88afd997ec0dfe342 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 29 May 2026 07:51:17 -0400
Subject: [PATCH 051/222] chore: remove `on_fork_commit` (#18318)

Simon thinks it was because he thought that committing the fork != committing the batch, and that this could result in an error boundary showing up too late. But that's not the case
---
 .../internal/client/dom/blocks/boundary.js    |  2 +-
 .../src/internal/client/reactivity/batch.js   | 21 -------------------
 2 files changed, 1 insertion(+), 22 deletions(-)

diff --git a/packages/svelte/src/internal/client/dom/blocks/boundary.js b/packages/svelte/src/internal/client/dom/blocks/boundary.js
index beaa7d6869..0c0903ff52 100644
--- a/packages/svelte/src/internal/client/dom/blocks/boundary.js
+++ b/packages/svelte/src/internal/client/dom/blocks/boundary.js
@@ -396,7 +396,7 @@ export class Boundary {
 			if (this.#pending_effect) current_batch.skip_effect(this.#pending_effect);
 			if (this.#failed_effect) current_batch.skip_effect(this.#failed_effect);
 
-			current_batch.on_fork_commit(() => {
+			current_batch.oncommit(() => {
 				this.#handle_error(error);
 			});
 		} else {
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 8dbcacf429..3b82059788 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -140,12 +140,6 @@ export class Batch {
 	 */
 	#discard_callbacks = new Set();
 
-	/**
-	 * Callbacks that should run only when a fork is committed.
-	 * @type {Set<(batch: Batch) => void>}
-	 */
-	#fork_commit_callbacks = new Set();
-
 	/**
 	 * The number of async effects that are currently in flight
 	 */
@@ -634,7 +628,6 @@ export class Batch {
 	discard() {
 		for (const fn of this.#discard_callbacks) fn(this);
 		this.#discard_callbacks.clear();
-		this.#fork_commit_callbacks.clear();
 
 		this.#unlink();
 		this.#deferred?.resolve();
@@ -840,16 +833,6 @@ export class Batch {
 		this.#discard_callbacks.add(fn);
 	}
 
-	/** @param {(batch: Batch) => void} fn */
-	on_fork_commit(fn) {
-		this.#fork_commit_callbacks.add(fn);
-	}
-
-	run_fork_commit_callbacks() {
-		for (const fn of this.#fork_commit_callbacks) fn(this);
-		this.#fork_commit_callbacks.clear();
-	}
-
 	settled() {
 		return (this.#deferred ??= deferred()).promise;
 	}
@@ -1410,10 +1393,6 @@ export function fork(fn) {
 				source.wv = increment_write_version();
 			}
 
-			batch.activate();
-			batch.run_fork_commit_callbacks();
-			batch.deactivate();
-
 			// trigger any `$state.eager(...)` expressions with the new state.
 			// eager effects don't get scheduled like other effects, so we
 			// can't just encounter them during traversal, we need to

From 3fad9cf8380889dfda288bcd0e10bcdbb8136f35 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 29 May 2026 07:54:33 -0400
Subject: [PATCH 052/222] chore: fix browser-support regression check (#18316)

vercel bot caught this in the release PR
https://github.com/sveltejs/svelte/pull/18315#pullrequestreview-4383622174
---
 .github/workflows/ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4f72b6c23e..c25e191702 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -99,7 +99,7 @@ jobs:
         if: (${{ success() }} || ${{ failure() }}) # ensures this step runs even if previous steps fail
         run: pnpm build && { [ "`git status --porcelain=v1`" == "" ] || (echo "Generated types have changed — please regenerate types locally with `cd packages/svelte && pnpm generate:types` and commit the changes after you have reviewed them"; git diff; exit 1); }
       - name: check browser-support docs page is up to date
-        run: '{ [ "`git status --porcelain=v1 documentation/docs/07-misc/05-browser-support.md`" == "" ] || (echo "The browser-support docs page is out of date — please regenerate it locally with \`cd packages/svelte && pnpm generate:browser-support\` and commit the changes"; git diff documentation/docs/07-misc/05-browser-support.md; exit 1); }'
+        run: '{ [ "`git status --porcelain=v1 documentation/docs/07-misc/.generated/`" == "" ] || (echo "The browser-support docs page is out of date — please regenerate it locally with \`cd packages/svelte && pnpm generate:browser-support\` and commit the changes"; git diff documentation/docs/07-misc/.generated/; exit 1); }'
   Benchmarks:
     permissions: {}
     runs-on: ubuntu-latest

From 656dae67808651fa6a7ca5f8446e28e3a4e76a62 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 29 May 2026 07:55:42 -0400
Subject: [PATCH 053/222] chore: try and discourage slop, even a tiny bit
 (#18293)

i don't know how to stem the flood of slop PRs but maybe this will help
a tiny bit

---------

Co-authored-by: vercel[bot] <35613825+vercel[bot]@users.noreply.github.com>
---
 AGENTS.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/AGENTS.md b/AGENTS.md
index c6cd3ea310..7f143248aa 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -4,6 +4,8 @@ This guide is for AI coding agents working in the Svelte monorepo.
 
 **Important:** Read and follow [`CONTRIBUTING.md`](./CONTRIBUTING.md) as well - it contains essential information about testing, code structure, and contribution guidelines that applies here.
 
+When submitting a PR, you **MUST** read [`PULL_REQUEST_TEMPLATE.md`](./.github/PULL_REQUEST_TEMPLATE.md) and fill it out correctly. **DO NOT** submit a PR without running the full test suite.
+
 ## Quick Reference
 
 If asked to do a performance investigation, use the `performance-investigation` skill.

From 59d3a36f825d9f2ca29dbdbec0ad27e4f5bf1105 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Fri, 29 May 2026 14:05:13 +0200
Subject: [PATCH 054/222] feat: allow declarations in the template (#18282)

Allows `{let/const ...}` declarations in all places (and more) where we
already allow `{@const ...}` (which will eventually get deprecated in
favor of this new feature).

Closes: #16490


Companion PRs:
- https://github.com/sveltejs/language-tools/pull/3033
- https://github.com/sveltejs/prettier-plugin-svelte/pull/533
- https://github.com/sveltejs/eslint-plugin-svelte/pull/1533
- https://github.com/sveltejs/svelte-eslint-parser/pull/891

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/four-loops-agree.md                |   5 +
 .../docs/03-template-syntax/10-@const.md      |   2 +
 .../03-template-syntax/11-declaration-tags.md |  70 +++++++++++
 .../98-reference/.generated/compile-errors.md |  12 ++
 .../messages/compile-errors/template.md       |   8 ++
 packages/svelte/src/compiler/errors.js        |  18 +++
 packages/svelte/src/compiler/legacy.js        |   4 +
 .../src/compiler/phases/1-parse/acorn.js      |  45 ++++++-
 .../src/compiler/phases/1-parse/index.js      |   5 +-
 .../src/compiler/phases/1-parse/state/tag.js  |  92 +++++++++++++-
 .../src/compiler/phases/2-analyze/index.js    |   5 +
 .../src/compiler/phases/2-analyze/types.d.ts  |   4 +-
 .../2-analyze/visitors/CallExpression.js      |   3 +
 .../phases/2-analyze/visitors/ConstTag.js     |  27 +----
 .../2-analyze/visitors/DeclarationTag.js      |  58 +++++++++
 .../phases/2-analyze/visitors/Identifier.js   |   2 +-
 .../3-transform/client/transform-client.js    |  19 +--
 .../phases/3-transform/client/utils.js        |  21 ++++
 .../3-transform/client/visitors/ConstTag.js   |  37 ++----
 .../client/visitors/DeclarationTag.js         |  87 ++++++++++++++
 .../client/visitors/RegularElement.js         |  32 ++++-
 .../client/visitors/SvelteBoundary.js         |   9 +-
 .../3-transform/server/transform-server.js    |   2 +
 .../phases/3-transform/server/types.d.ts      |   2 +-
 .../3-transform/server/visitors/ConstTag.js   |  33 ++---
 .../server/visitors/DeclarationTag.js         |  85 +++++++++++++
 .../server/visitors/RegularElement.js         |  31 +++--
 .../src/compiler/phases/3-transform/utils.js  |   1 +
 packages/svelte/src/compiler/phases/nodes.js  |   1 +
 packages/svelte/src/compiler/print/index.js   |  42 +++++++
 .../svelte/src/compiler/types/template.d.ts   |  13 ++
 .../loose-declaration-tag/input.svelte        |   4 +
 .../samples/loose-declaration-tag/output.json | 113 ++++++++++++++++++
 .../samples/declaration-tag/input.svelte      |   7 ++
 .../samples/declaration-tag/output.svelte     |   7 ++
 .../async-declaration-tag-2/_config.js        |  13 ++
 .../async-declaration-tag-2/main.svelte       |  31 +++++
 .../samples/async-declaration-tag/_config.js  |  43 +++++++
 .../samples/async-declaration-tag/main.svelte |  20 ++++
 .../declaration-tags-no-script/_config.js     |  13 ++
 .../declaration-tags-no-script/main.svelte    |   3 +
 .../samples/declaration-tags/_config.js       |  37 ++++++
 .../samples/declaration-tags/main.svelte      |  29 +++++
 .../errors.json                               |  14 +++
 .../input.svelte                              |   3 +
 .../declaration-tag-invalid-type/errors.json  |  14 +++
 .../declaration-tag-invalid-type/input.svelte |   3 +
 .../declaration-tag-legacy-mode/errors.json   |  14 +++
 .../declaration-tag-legacy-mode/input.svelte  |   5 +
 .../declaration-tag-maybe-runes/errors.json   |   1 +
 .../declaration-tag-maybe-runes/input.svelte  |   6 +
 packages/svelte/types/index.d.ts              |   7 ++
 52 files changed, 1053 insertions(+), 109 deletions(-)
 create mode 100644 .changeset/four-loops-agree.md
 create mode 100644 documentation/docs/03-template-syntax/11-declaration-tags.md
 create mode 100644 packages/svelte/src/compiler/phases/2-analyze/visitors/DeclarationTag.js
 create mode 100644 packages/svelte/src/compiler/phases/3-transform/client/visitors/DeclarationTag.js
 create mode 100644 packages/svelte/src/compiler/phases/3-transform/server/visitors/DeclarationTag.js
 create mode 100644 packages/svelte/tests/parser-modern/samples/loose-declaration-tag/input.svelte
 create mode 100644 packages/svelte/tests/parser-modern/samples/loose-declaration-tag/output.json
 create mode 100644 packages/svelte/tests/print/samples/declaration-tag/input.svelte
 create mode 100644 packages/svelte/tests/print/samples/declaration-tag/output.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-declaration-tag-2/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-declaration-tag-2/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-declaration-tag/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-declaration-tag/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/declaration-tags-no-script/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/declaration-tags-no-script/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/declaration-tags/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/declaration-tags/main.svelte
 create mode 100644 packages/svelte/tests/validator/samples/declaration-tag-invalid-function/errors.json
 create mode 100644 packages/svelte/tests/validator/samples/declaration-tag-invalid-function/input.svelte
 create mode 100644 packages/svelte/tests/validator/samples/declaration-tag-invalid-type/errors.json
 create mode 100644 packages/svelte/tests/validator/samples/declaration-tag-invalid-type/input.svelte
 create mode 100644 packages/svelte/tests/validator/samples/declaration-tag-legacy-mode/errors.json
 create mode 100644 packages/svelte/tests/validator/samples/declaration-tag-legacy-mode/input.svelte
 create mode 100644 packages/svelte/tests/validator/samples/declaration-tag-maybe-runes/errors.json
 create mode 100644 packages/svelte/tests/validator/samples/declaration-tag-maybe-runes/input.svelte

diff --git a/.changeset/four-loops-agree.md b/.changeset/four-loops-agree.md
new file mode 100644
index 0000000000..46d30e8464
--- /dev/null
+++ b/.changeset/four-loops-agree.md
@@ -0,0 +1,5 @@
+---
+'svelte': minor
+---
+
+feat: allow declarations in the template
diff --git a/documentation/docs/03-template-syntax/10-@const.md b/documentation/docs/03-template-syntax/10-@const.md
index 2a587b7a3d..6f2edc1a37 100644
--- a/documentation/docs/03-template-syntax/10-@const.md
+++ b/documentation/docs/03-template-syntax/10-@const.md
@@ -2,6 +2,8 @@
 title: {@const ...}
 ---
 
+> [!NOTE] `{@const x = y}` is legacy syntax — use [`{const x = $derived(y)}`](declaration-tags) instead
+
 The `{@const ...}` tag defines a local constant.
 
 ```svelte
diff --git a/documentation/docs/03-template-syntax/11-declaration-tags.md b/documentation/docs/03-template-syntax/11-declaration-tags.md
new file mode 100644
index 0000000000..34b7164775
--- /dev/null
+++ b/documentation/docs/03-template-syntax/11-declaration-tags.md
@@ -0,0 +1,70 @@
+---
+title: {let/const ...}
+---
+
+Declaration tags define local variables inside markup with `const` or `let`:
+
+<!-- codeblock:start {"title":"Declaration tags"} -->
+```svelte
+<!--- file: App.svelte --->
+<script>
+	let boxes = [{ width: 10, height: 10 }, { width: 15, height: 15 }];
+</script>
+
+{#each boxes as box}
+	{const area = box.width * box.height}
+	{const label = `${box.width} ⨉ ${box.height} = ${area}`}
+
+	<p>{label}</p>
+{/each}
+```
+<!-- codeblock:end -->
+
+> [!NOTE] The [`{@const ...}`](@const) syntax is considered legacy — use declaration tags instead.
+
+When values should be reactive, you can use `$state` and `$derived`:
+
+<!-- codeblock:start {"title":"Reactive declaration tags"} -->
+```svelte
+<!--- file: App.svelte --->
+<script>
+	let user = $state({ name: 'Svelte' });
+	let editing = $state(false);
+</script>
+
+<p>Hello {user.name}</p>
+<button onclick={() => editing = true}>edit name</button>
+
+{#if editing}
+	{let name = $state(user.name)}
+	{const greeting = $derived(`Hello ${name}`)}
+
+	<hr>
+	<input bind:value={name} />
+	<p>{greeting}</p>
+
+	<button onclick={() => {
+		user.name = name;
+		editing = false;
+	}}>save</button>
+{/if}
+```
+<!-- codeblock:end -->
+
+Declaration tags can be used anywhere inside the component. They can reference values declared outside themselves (for example in the `<script>` tag or in `{#each ...}` blocks) and are 'visible' to everything in the same lexical scope (i.e. siblings, and children of those siblings):
+
+<!-- codeblock:start {"title":"Declaration tag scope"} -->
+```svelte
+<!--- file: App.svelte --->
+{const hello = 'hello'}
+{hello} <!-- 'hello' -->
+<div>
+	{const hello = 'hi'}
+	{hello} <!-- 'hi' -->
+	<div>
+		{hello} <!-- 'hi' -->
+	</div>
+</div>
+{hello} <!-- 'hello' -->
+```
+<!-- codeblock:end -->
diff --git a/documentation/docs/98-reference/.generated/compile-errors.md b/documentation/docs/98-reference/.generated/compile-errors.md
index 01b2dd1494..0d25173711 100644
--- a/documentation/docs/98-reference/.generated/compile-errors.md
+++ b/documentation/docs/98-reference/.generated/compile-errors.md
@@ -399,6 +399,18 @@ Invalid selector
 Cannot declare a variable with the same name as an import from `<script module>`
 ```
 
+### declaration_tag_invalid_type
+
+```
+Declaration tags must be `let` or `const` declarations
+```
+
+### declaration_tag_no_legacy_mode
+
+```
+Declaration tags cannot be used in legacy mode
+```
+
 ### derived_invalid_export
 
 ```
diff --git a/packages/svelte/messages/compile-errors/template.md b/packages/svelte/messages/compile-errors/template.md
index 6aa4335c11..6d1ae6ccbf 100644
--- a/packages/svelte/messages/compile-errors/template.md
+++ b/packages/svelte/messages/compile-errors/template.md
@@ -191,6 +191,14 @@ The same applies to components:
 
 > {@debug ...} arguments must be identifiers, not arbitrary expressions
 
+## declaration_tag_invalid_type
+
+> Declaration tags must be `let` or `const` declarations
+
+## declaration_tag_no_legacy_mode
+
+> Declaration tags cannot be used in legacy mode
+
 ## directive_invalid_value
 
 > Directive value must be a JavaScript expression enclosed in curly braces
diff --git a/packages/svelte/src/compiler/errors.js b/packages/svelte/src/compiler/errors.js
index 976925d181..ccb7fe833e 100644
--- a/packages/svelte/src/compiler/errors.js
+++ b/packages/svelte/src/compiler/errors.js
@@ -1004,6 +1004,24 @@ export function debug_tag_invalid_arguments(node) {
 	e(node, 'debug_tag_invalid_arguments', `{@debug ...} arguments must be identifiers, not arbitrary expressions\nhttps://svelte.dev/e/debug_tag_invalid_arguments`);
 }
 
+/**
+ * Declaration tags must be `let` or `const` declarations
+ * @param {null | number | NodeLike} node
+ * @returns {never}
+ */
+export function declaration_tag_invalid_type(node) {
+	e(node, 'declaration_tag_invalid_type', `Declaration tags must be \`let\` or \`const\` declarations\nhttps://svelte.dev/e/declaration_tag_invalid_type`);
+}
+
+/**
+ * Declaration tags cannot be used in legacy mode
+ * @param {null | number | NodeLike} node
+ * @returns {never}
+ */
+export function declaration_tag_no_legacy_mode(node) {
+	e(node, 'declaration_tag_no_legacy_mode', `Declaration tags cannot be used in legacy mode\nhttps://svelte.dev/e/declaration_tag_no_legacy_mode`);
+}
+
 /**
  * Directive value must be a JavaScript expression enclosed in curly braces
  * @param {null | number | NodeLike} node
diff --git a/packages/svelte/src/compiler/legacy.js b/packages/svelte/src/compiler/legacy.js
index 459858fe13..c51cd8434b 100644
--- a/packages/svelte/src/compiler/legacy.js
+++ b/packages/svelte/src/compiler/legacy.js
@@ -262,6 +262,10 @@ export function convert(source, ast) {
 				};
 			},
 			// @ts-ignore
+			DeclarationTag(node) {
+				return node;
+			},
+			// @ts-ignore
 			KeyBlock(node, { visit }) {
 				remove_surrounding_whitespace_nodes(node.fragment.nodes);
 				return {
diff --git a/packages/svelte/src/compiler/phases/1-parse/acorn.js b/packages/svelte/src/compiler/phases/1-parse/acorn.js
index 45a7c2a58c..d338f9ffb8 100644
--- a/packages/svelte/src/compiler/phases/1-parse/acorn.js
+++ b/packages/svelte/src/compiler/phases/1-parse/acorn.js
@@ -1,10 +1,11 @@
-/** @import { Comment, Program } from 'estree' */
+/** @import { Comment, Program, Statement } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { Parser } from './index.js' */
 import * as acorn from 'acorn';
 import { walk } from 'zimmerframe';
 import { tsPlugin } from '@sveltejs/acorn-typescript';
 import * as e from '../../errors.js';
+import { find_matching_bracket } from './utils/bracket.js';
 
 const JSParser = acorn.Parser;
 const TSParser = JSParser.extend(tsPlugin());
@@ -98,6 +99,48 @@ export function parse_expression_at(parser, source, index) {
 	}
 }
 
+/**
+ * @param {Parser} parser
+ * @param {string} source
+ * @param {number} index
+ * @returns {Statement}
+ */
+export function parse_statement_at(parser, source, index) {
+	const acorn = parser.ts ? TSParser : JSParser;
+	let end = find_matching_bracket(source, index, '{');
+	if (end === undefined) e.unexpected_eof(source.length);
+
+	while (source[end - 1] === ';') {
+		end -= 1;
+	}
+
+	const padded_source = `${' '.repeat(index)}${source.slice(index, end)}`;
+	const { onComment, add_comments } = get_comment_handlers(
+		padded_source,
+		parser.root.comments,
+		index
+	);
+
+	try {
+		const ast = acorn.parse(padded_source, {
+			onComment,
+			sourceType: 'module',
+			ecmaVersion: 16,
+			locations: true
+		});
+
+		add_comments(ast);
+
+		const statement = /** @type {Statement} */ (
+			/** @type {unknown} */ (/** @type {Program} */ (ast).body[0])
+		);
+		statement.end = Math.min(/** @type {number} */ (statement.end), end);
+		return statement;
+	} catch (e) {
+		handle_parse_error(e);
+	}
+}
+
 const regex_position_indicator = / \(\d+:\d+\)$/;
 
 /**
diff --git a/packages/svelte/src/compiler/phases/1-parse/index.js b/packages/svelte/src/compiler/phases/1-parse/index.js
index 5242cba31f..02d1629c99 100644
--- a/packages/svelte/src/compiler/phases/1-parse/index.js
+++ b/packages/svelte/src/compiler/phases/1-parse/index.js
@@ -302,7 +302,10 @@ export class Parser {
 	}
 
 	pop() {
-		this.fragments.pop();
+		const fragment = this.fragments.pop();
+		if (fragment?.metadata.transparent && fragment.nodes.some((n) => n.type === 'DeclarationTag')) {
+			fragment.metadata.transparent = false;
+		}
 		return this.stack.pop();
 	}
 
diff --git a/packages/svelte/src/compiler/phases/1-parse/state/tag.js b/packages/svelte/src/compiler/phases/1-parse/state/tag.js
index ff153128a5..7428c8660c 100644
--- a/packages/svelte/src/compiler/phases/1-parse/state/tag.js
+++ b/packages/svelte/src/compiler/phases/1-parse/state/tag.js
@@ -1,16 +1,18 @@
-/** @import { ArrowFunctionExpression, Expression, Identifier, Pattern } from 'estree' */
+/** @import { ArrowFunctionExpression, Expression, Identifier, Pattern, VariableDeclaration } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { Parser } from '../index.js' */
 import { walk } from 'zimmerframe';
 import * as e from '../../../errors.js';
 import { ExpressionMetadata } from '../../nodes.js';
-import { parse_expression_at } from '../acorn.js';
+import { parse_expression_at, parse_statement_at } from '../acorn.js';
 import read_pattern from '../read/context.js';
 import read_expression, { get_loose_identifier } from '../read/expression.js';
 import { create_fragment } from '../utils/create.js';
-import { match_bracket } from '../utils/bracket.js';
+import { find_matching_bracket, match_bracket } from '../utils/bracket.js';
 
 const regex_whitespace_with_closing_curly_brace = /\s*}/y;
+const regex_supported_declaration = /(?:let|const)\b/y;
+const regex_unsupported_declaration = /(?:var|function|class|type|interface|enum)\b/y;
 
 const pointy_bois = { '<': '>' };
 
@@ -31,6 +33,20 @@ export default function tag(parser) {
 		}
 	}
 
+	const declaration = read_declaration(parser);
+	if (declaration) {
+		parser.append({
+			type: 'DeclarationTag',
+			start,
+			end: parser.index,
+			declaration: /** @type {VariableDeclaration} */ (declaration),
+			metadata: {
+				expression: new ExpressionMetadata()
+			}
+		});
+		return;
+	}
+
 	const expression = read_expression(parser);
 
 	parser.allow_whitespace();
@@ -47,6 +63,76 @@ export default function tag(parser) {
 	});
 }
 
+/**
+ * @param {Parser} parser
+ * @returns {null | import('estree').VariableDeclaration}
+ */
+function read_declaration(parser) {
+	const start = parser.index;
+
+	const unsupported = parser.match_regex(regex_unsupported_declaration);
+	if (unsupported) {
+		e.declaration_tag_invalid_type({ start, end: start + unsupported.length });
+	}
+
+	if (!parser.match_regex(regex_supported_declaration)) {
+		return null;
+	}
+
+	/** @type {import('estree').Statement | import('estree').VariableDeclaration} */
+	let declaration;
+	try {
+		declaration = parse_statement_at(parser, parser.template, start);
+	} catch (error) {
+		if (!parser.loose) throw error;
+
+		const end = find_matching_bracket(parser.template, start, '{');
+		if (end === undefined) throw error;
+
+		parser.index = end;
+		const kind = parser.template.startsWith('const', start) ? 'const' : 'let';
+
+		declaration = {
+			type: 'VariableDeclaration',
+			kind,
+			declarations: [
+				{
+					type: 'VariableDeclarator',
+					id: {
+						type: 'Identifier',
+						name: '',
+						start: parser.index,
+						end: parser.index
+					},
+					init: null,
+					start: parser.index,
+					end: parser.index
+				}
+			],
+			start,
+			end
+		};
+	}
+
+	if (declaration.type !== 'VariableDeclaration') {
+		e.declaration_tag_invalid_type({
+			start: declaration.start ?? start,
+			end: declaration.end ?? parser.index
+		});
+	}
+
+	// TODO support using
+	if (declaration.kind !== 'let' && declaration.kind !== 'const') {
+		e.declaration_tag_invalid_type(declaration);
+	}
+
+	parser.index = /** @type {number} */ (declaration.end);
+	parser.allow_whitespace();
+	parser.eat('}', true);
+
+	return declaration;
+}
+
 /** @param {Parser} parser */
 function open(parser) {
 	let start = parser.index - 2;
diff --git a/packages/svelte/src/compiler/phases/2-analyze/index.js b/packages/svelte/src/compiler/phases/2-analyze/index.js
index dec0081aa9..ef20049697 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/index.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/index.js
@@ -36,6 +36,7 @@ import { ClassDeclaration } from './visitors/ClassDeclaration.js';
 import { ClassDirective } from './visitors/ClassDirective.js';
 import { Component } from './visitors/Component.js';
 import { ConstTag } from './visitors/ConstTag.js';
+import { DeclarationTag } from './visitors/DeclarationTag.js';
 import { DebugTag } from './visitors/DebugTag.js';
 import { EachBlock } from './visitors/EachBlock.js';
 import { ExportDefaultDeclaration } from './visitors/ExportDefaultDeclaration.js';
@@ -157,6 +158,7 @@ const visitors = {
 	ClassDirective,
 	Component,
 	ConstTag,
+	DeclarationTag,
 	DebugTag,
 	EachBlock,
 	ExportDefaultDeclaration,
@@ -312,6 +314,7 @@ export function analyze_module(source, options) {
 			options: /** @type {ValidatedCompileOptions} */ (options),
 			fragment: null,
 			parent_element: null,
+			in_declaration_tag: false,
 			reactive_statement: null,
 			derived_function_depth: -1
 		},
@@ -718,6 +721,7 @@ export function analyze_component(root, source, options) {
 				ast_type: ast === instance.ast ? 'instance' : ast === template.ast ? 'template' : 'module',
 				fragment: ast === template.ast ? ast : null,
 				parent_element: null,
+				in_declaration_tag: false,
 				has_props_rune: false,
 				component_slots: new Set(),
 				expression: null,
@@ -785,6 +789,7 @@ export function analyze_component(root, source, options) {
 				options,
 				fragment: ast === template.ast ? ast : null,
 				parent_element: null,
+				in_declaration_tag: false,
 				has_props_rune: false,
 				ast_type: ast === instance.ast ? 'instance' : ast === template.ast ? 'template' : 'module',
 				reactive_statement: null,
diff --git a/packages/svelte/src/compiler/phases/2-analyze/types.d.ts b/packages/svelte/src/compiler/phases/2-analyze/types.d.ts
index 354f1c0856..bd486a12ca 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/types.d.ts
+++ b/packages/svelte/src/compiler/phases/2-analyze/types.d.ts
@@ -16,6 +16,8 @@ export interface AnalysisState {
 	 * Parent doesn't necessarily mean direct path predecessor because there could be `#each`, `#if` etc in-between.
 	 */
 	parent_element: string | null;
+	/** True if inside DeclarationTag */
+	in_declaration_tag: boolean;
 	has_props_rune: boolean;
 	/** Which slots the current parent component has */
 	component_slots: Set<string>;
@@ -35,7 +37,7 @@ export interface AnalysisState {
 	 */
 	derived_function_depth: number;
 
-	/** Collected info about async `{@const }` declarations */
+	/** Collected info about async `{@const }`/`{let/const ...}` declarations */
 	async_consts?: {
 		id: Identifier;
 		/** How many `$.run(...)` entries are already allocated in this scope */
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js
index 52eba8c735..d3524af4db 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js
@@ -255,6 +255,9 @@ export function CallExpression(node, context) {
 		if (expression.has_await) {
 			context.state.analysis.async_deriveds.add(node);
 		}
+
+		// Tell surrounding declaration tag about metadata for correct calculation of blockers etc
+		if (context.state.in_declaration_tag) context.state.expression?.merge(expression);
 	} else if (rune === '$inspect') {
 		context.next({ ...context.state, function_depth: context.state.function_depth + 1 });
 	} else {
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/ConstTag.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/ConstTag.js
index 4f07249a39..64e93d3efe 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/ConstTag.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/ConstTag.js
@@ -1,8 +1,8 @@
 /** @import { AST } from '#compiler' */
 /** @import { Context } from '../types' */
 import * as e from '../../../errors.js';
-import * as b from '#compiler/builders';
 import { validate_opening_tag } from './shared/utils.js';
+import { mark_async_declaration } from './DeclarationTag.js';
 
 /**
  * @param {AST.ConstTag} node
@@ -44,28 +44,5 @@ export function ConstTag(node, context) {
 		derived_function_depth: context.state.function_depth + 1
 	});
 
-	const has_await = node.metadata.expression.has_await;
-	const blockers = [...node.metadata.expression.dependencies]
-		.map((dep) => dep.blocker)
-		.filter((b) => b !== null && b.object !== context.state.async_consts?.id);
-
-	if (has_await || context.state.async_consts || blockers.length > 0) {
-		const run = (context.state.async_consts ??= {
-			id: context.state.analysis.root.unique('promises'),
-			declaration_count: 0
-		});
-		node.metadata.promises_id = run.id;
-
-		const bindings = context.state.scope.get_bindings(declaration);
-
-		// keep the counter in sync with the number of thunks pushed in ConstTag in transform
-		// TODO 6.0 once non-async and non-runes mode is gone investigate making this more robust
-		// via something like the approach in https://github.com/sveltejs/svelte/pull/18032
-		const length = run.declaration_count + (blockers.length > 0 ? 1 : 0);
-		run.declaration_count += blockers.length > 0 ? 2 : 1;
-		const blocker = b.member(run.id, b.literal(length), true);
-		for (const binding of bindings) {
-			binding.blocker = blocker;
-		}
-	}
+	mark_async_declaration(context, node.metadata, [declaration]);
 }
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/DeclarationTag.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/DeclarationTag.js
new file mode 100644
index 0000000000..e75c05f355
--- /dev/null
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/DeclarationTag.js
@@ -0,0 +1,58 @@
+/** @import { AST } from '#compiler' */
+/** @import { Context } from '../types' */
+import * as b from '#compiler/builders';
+import * as e from '../../../errors.js';
+import { validate_opening_tag } from './shared/utils.js';
+
+/**
+ * @param {AST.DeclarationTag} node
+ * @param {Context} context
+ */
+export function DeclarationTag(node, context) {
+	validate_opening_tag(node, context.state, node.declaration.kind[0]);
+	if (!context.state.analysis.runes && !context.state.analysis.maybe_runes) {
+		e.declaration_tag_no_legacy_mode(node);
+	}
+
+	context.visit(node.declaration, {
+		...context.state,
+		in_declaration_tag: true,
+		expression: node.metadata.expression
+	});
+
+	mark_async_declaration(context, node.metadata, node.declaration.declarations);
+}
+
+/**
+ * @param {Context} context
+ * @param {AST.ConstTag['metadata'] | AST.DeclarationTag['metadata']} metadata
+ * @param {import('estree').VariableDeclarator[]} declarations
+ */
+export function mark_async_declaration(context, metadata, declarations) {
+	const has_await = metadata.expression.has_await;
+	const blockers = [...metadata.expression.dependencies]
+		.map((dep) => dep.blocker)
+		.filter((b) => b !== null && b.object !== context.state.async_consts?.id);
+
+	if (has_await || context.state.async_consts || blockers.length > 0) {
+		const run = (context.state.async_consts ??= {
+			id: context.state.analysis.root.unique('promises'),
+			declaration_count: 0
+		});
+		metadata.promises_id = run.id;
+
+		const bindings = declarations.flatMap((declaration) =>
+			context.state.scope.get_bindings(declaration)
+		);
+
+		// keep the counter in sync with the number of thunks pushed in transform
+		// TODO 6.0 once non-async and non-runes mode is gone investigate making this more robust
+		// via something like the approach in https://github.com/sveltejs/svelte/pull/18032
+		const length = run.declaration_count + (blockers.length > 0 ? 1 : 0);
+		run.declaration_count += blockers.length > 0 ? 2 : 1;
+		const blocker = b.member(run.id, b.literal(length), true);
+		for (const binding of bindings) {
+			binding.blocker = blocker;
+		}
+	}
+}
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/Identifier.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/Identifier.js
index 5c1e8031b8..ebb2fc2b67 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/Identifier.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/Identifier.js
@@ -162,7 +162,7 @@ export function Identifier(node, context) {
 		if (binding.metadata?.is_template_declaration && context.state.options.experimental.async) {
 			let snippet_name;
 
-			// Find out if this references a {@const ...} declaration of an implicit children snippet
+			// Find out if this references a {@const ...}/{let/const ...} declaration of an implicit children snippet
 			// when it is itself inside a snippet block at the same level. If so, error.
 			for (let i = context.path.length - 1; i >= 0; i--) {
 				const parent = context.path[i];
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js b/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js
index 5cd837d08e..6a71a49601 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js
@@ -4,7 +4,7 @@
 /** @import { Visitors, ComponentClientTransformState, ClientTransformState } from './types' */
 import { walk } from 'zimmerframe';
 import * as b from '#compiler/builders';
-import { build_getter, is_state_source } from './utils.js';
+import { build_getter, get_transform } from './utils.js';
 import { render_stylesheet } from '../css/index.js';
 import { dev, filename } from '../../../state.js';
 import { AnimateDirective } from './visitors/AnimateDirective.js';
@@ -22,6 +22,7 @@ import { ClassBody } from './visitors/ClassBody.js';
 import { Comment } from './visitors/Comment.js';
 import { Component } from './visitors/Component.js';
 import { ConstTag } from './visitors/ConstTag.js';
+import { DeclarationTag } from './visitors/DeclarationTag.js';
 import { DebugTag } from './visitors/DebugTag.js';
 import { EachBlock } from './visitors/EachBlock.js';
 import { ExportNamedDeclaration } from './visitors/ExportNamedDeclaration.js';
@@ -66,20 +67,7 @@ const visitors = {
 		const scope = state.scopes.get(node);
 
 		if (scope && scope !== state.scope) {
-			const transform = { ...state.transform };
-
-			for (const [name, binding] of scope.declarations) {
-				if (
-					binding.kind === 'normal' ||
-					// Reads of `$state(...)` declarations are not
-					// transformed if they are never reassigned
-					(binding.kind === 'state' && !is_state_source(binding, state.analysis))
-				) {
-					delete transform[name];
-				}
-			}
-
-			next({ ...state, transform, scope });
+			next({ ...state, transform: get_transform(scope, state), scope });
 		} else {
 			next();
 		}
@@ -99,6 +87,7 @@ const visitors = {
 	Comment,
 	Component,
 	ConstTag,
+	DeclarationTag,
 	DebugTag,
 	EachBlock,
 	ExportNamedDeclaration,
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/utils.js b/packages/svelte/src/compiler/phases/3-transform/client/utils.js
index f21fb43fc1..d52b438d92 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/utils.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/utils.js
@@ -179,3 +179,24 @@ export function create_derived(state, expression, async = false) {
 		return b.call(state.analysis.runes ? '$.derived' : '$.derived_safe_equal', thunk);
 	}
 }
+
+/**
+ * @param {Scope} scope
+ * @param {ClientTransformState} state
+ */
+export function get_transform(scope, state) {
+	const transform = { ...state.transform };
+
+	for (const [name, binding] of scope.declarations) {
+		if (
+			binding.kind === 'normal' ||
+			// Reads of `$state(...)` declarations are not
+			// transformed if they are never reassigned
+			(binding.kind === 'state' && !is_state_source(binding, state.analysis))
+		) {
+			delete transform[name];
+		}
+	}
+
+	return transform;
+}
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/ConstTag.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/ConstTag.js
index bf559cd24d..d05d7a8ed9 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/ConstTag.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/ConstTag.js
@@ -7,6 +7,7 @@ import * as b from '#compiler/builders';
 import { create_derived } from '../utils.js';
 import { get_value } from './shared/declarations.js';
 import { build_expression } from './shared/utils.js';
+import { add_async_declaration } from './DeclarationTag.js';
 
 /**
  * @param {AST.ConstTag} node
@@ -26,7 +27,7 @@ export function ConstTag(node, context) {
 
 		context.state.transform[declaration.id.name] = { read: get_value };
 
-		add_const_declaration(context.state, declaration.id, expression, node.metadata);
+		add_const_declaration(context, declaration.id, expression, node.metadata);
 	} else {
 		const identifiers = extract_identifiers(declaration.id);
 		const tmp = b.id(context.state.scope.generate('computed_const'));
@@ -63,7 +64,7 @@ export function ConstTag(node, context) {
 			expression = b.call('$.tag', expression, b.literal('[@const]'));
 		}
 
-		add_const_declaration(context.state, tmp, expression, node.metadata);
+		add_const_declaration(context, tmp, expression, node.metadata);
 
 		for (const node of identifiers) {
 			context.state.transform[node.name] = {
@@ -74,38 +75,26 @@ export function ConstTag(node, context) {
 }
 
 /**
- * @param {ComponentContext['state']} state
+ * @param {ComponentContext} context
  * @param {Identifier} id
  * @param {Expression} expression
  * @param {AST.ConstTag['metadata']} metadata
  */
-function add_const_declaration(state, id, expression, metadata) {
+function add_const_declaration(context, id, expression, metadata) {
 	// we need to eagerly evaluate the expression in order to hit any
 	// 'Cannot access x before initialization' errors
 	const after = dev ? [b.stmt(b.call('$.get', id))] : [];
 
-	const blockers = [...metadata.expression.dependencies]
-		.map((dep) => dep.blocker)
-		.filter((b) => b !== null && b.object !== state.async_consts?.id);
-
 	if (metadata.promises_id) {
-		const run = (state.async_consts ??= {
-			id: metadata.promises_id,
-			thunks: []
-		});
-
-		state.consts.push(b.let(id));
-
-		if (blockers.length === 1) {
-			run.thunks.push(b.thunk(b.member(/** @type {Expression} */ (blockers[0]), 'promise')));
-		} else if (blockers.length > 0) {
-			run.thunks.push(b.thunk(b.call('$.wait', b.array(blockers))));
-		}
-
-		// keep the number of thunks pushed in sync with ConstTag in analysis phase
-		const assignment = b.assignment('=', id, expression);
-		run.thunks.push(b.thunk(assignment, metadata.expression.has_await));
+		add_async_declaration(
+			context,
+			metadata,
+			[id],
+			[b.stmt(b.assignment('=', id, expression))],
+			'let'
+		);
 	} else {
+		const { state } = context;
 		state.consts.push(b.const(id, expression));
 		state.consts.push(...after);
 	}
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/DeclarationTag.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/DeclarationTag.js
new file mode 100644
index 0000000000..bff51b20dd
--- /dev/null
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/DeclarationTag.js
@@ -0,0 +1,87 @@
+/** @import { Expression, Identifier, Pattern, Statement, ExpressionStatement, VariableDeclaration } from 'estree' */
+/** @import { AST } from '#compiler' */
+/** @import { ComponentContext } from '../types' */
+import { extract_identifiers, has_await_expression } from '../../../../utils/ast.js';
+import * as b from '#compiler/builders';
+import { add_state_transformers } from './shared/declarations.js';
+
+/**
+ * @param {AST.DeclarationTag} node
+ * @param {ComponentContext} context
+ */
+export function DeclarationTag(node, context) {
+	const declaration = /** @type {Statement | undefined} */ (context.visit(node.declaration));
+	add_state_transformers(context);
+
+	if (
+		node.metadata.promises_id &&
+		node.declaration.type === 'VariableDeclaration' &&
+		declaration?.type === 'VariableDeclaration'
+	) {
+		const { ids, assignments } = build_async_declaration_parts(declaration);
+		add_async_declaration(context, node.metadata, ids, assignments, declaration.kind);
+	} else {
+		context.state.consts.push(declaration ?? node.declaration);
+	}
+}
+
+/**
+ * @param {VariableDeclaration} declaration
+ */
+export function build_async_declaration_parts(declaration) {
+	const ids = new Map();
+	for (const declarator of declaration.declarations) {
+		for (const id of extract_identifiers(declarator.id)) {
+			ids.set(id.name, id);
+		}
+	}
+
+	const assignments = declaration.declarations
+		.filter((declarator) => declarator.init !== null)
+		.map((declarator) =>
+			b.stmt(
+				b.assignment(
+					'=',
+					/** @type {Pattern} */ (declarator.id),
+					/** @type {Expression} */ (declarator.init)
+				)
+			)
+		);
+
+	return { ids: [...ids.values()], assignments };
+}
+
+/**
+ * @param {ComponentContext} context
+ * @param {AST.ConstTag['metadata'] | AST.DeclarationTag['metadata']} metadata
+ * @param {Identifier[]} ids
+ * @param {ExpressionStatement[]} assignments
+ * @param {VariableDeclaration['kind']} [kind]
+ */
+export function add_async_declaration(context, metadata, ids, assignments, kind = 'let') {
+	const run = (context.state.async_consts ??= {
+		id: /** @type {Identifier} */ (metadata.promises_id),
+		thunks: []
+	});
+
+	for (const id of ids) {
+		context.state.consts.push(kind === 'var' ? b.var(id.name) : b.let(id.name));
+	}
+
+	const blockers = [...metadata.expression.dependencies]
+		.map((dep) => dep.blocker)
+		.filter((b) => b !== null && b.object !== context.state.async_consts?.id);
+
+	if (blockers.length === 1) {
+		run.thunks.push(b.thunk(b.member(/** @type {Expression} */ (blockers[0]), 'promise')));
+	} else if (blockers.length > 0) {
+		run.thunks.push(b.thunk(b.call('$.wait', b.array(blockers))));
+	}
+
+	// keep the number of thunks pushed in sync with analysis phase
+	const has_await =
+		metadata.expression.has_await ||
+		assignments.some((assignment) => has_await_expression(assignment));
+	const body = assignments.length === 1 ? assignments[0].expression : b.block(assignments);
+	run.thunks.push(b.thunk(body, has_await));
+}
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
index 1e6230a1f6..543f4aea17 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
@@ -18,7 +18,7 @@ import {
 	is_customizable_select_element
 } from '../../../nodes.js';
 import { clean_nodes, determine_namespace_for_children } from '../../utils.js';
-import { build_getter } from '../utils.js';
+import { build_getter, get_transform } from '../utils.js';
 import {
 	get_attribute_name,
 	build_attribute_value,
@@ -300,11 +300,14 @@ export function RegularElement(node, context) {
 		}
 	}
 
+	const scope = /** @type {Scope} */ (context.state.scopes.get(node.fragment));
+
 	/** @type {ComponentClientTransformState} */
 	const state = {
 		...context.state,
 		metadata,
-		scope: /** @type {Scope} */ (context.state.scopes.get(node.fragment)),
+		scope,
+		transform: get_transform(scope, context.state),
 		preserve_whitespace: context.state.preserve_whitespace || name === 'pre' || name === 'textarea'
 	};
 
@@ -318,8 +321,19 @@ export function RegularElement(node, context) {
 		state.options.preserveComments
 	);
 
+	const has_declarations = !node.fragment.metadata.transparent;
+
 	/** @type {typeof state} */
-	const child_state = { ...state, init: [], update: [], after_update: [], snippets: [] };
+	const child_state = {
+		...state,
+		init: [],
+		update: [],
+		after_update: [],
+		snippets: [],
+		consts: has_declarations ? [] : state.consts,
+		async_consts: has_declarations ? undefined : state.async_consts,
+		memoizer: has_declarations ? new Memoizer() : state.memoizer
+	};
 
 	for (const node of hoisted) {
 		context.visit(node, child_state);
@@ -427,11 +441,21 @@ export function RegularElement(node, context) {
 		}
 	}
 
-	if (node.fragment.nodes.some((node) => node.type === 'SnippetBlock')) {
+	if (node.fragment.nodes.some((node) => node.type === 'SnippetBlock') || has_declarations) {
+		if (child_state.async_consts && child_state.async_consts.thunks.length > 0) {
+			child_state.consts.push(
+				b.var(
+					child_state.async_consts.id,
+					b.call('$.run', b.array(child_state.async_consts.thunks))
+				)
+			);
+		}
+
 		// Wrap children in `{...}` to avoid declaration conflicts
 		context.state.init.push(
 			b.block([
 				...child_state.snippets,
+				...child_state.consts,
 				...child_state.init,
 				...element_state.init,
 				child_state.update.length > 0 ? build_render_statement(child_state) : b.empty,
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/SvelteBoundary.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/SvelteBoundary.js
index f929a3bc47..eaffd15084 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/SvelteBoundary.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/SvelteBoundary.js
@@ -40,6 +40,7 @@ export function SvelteBoundary(node, context) {
 	const hoisted = [];
 
 	let has_const = false;
+	let has_declaration = false;
 
 	// const tags need to live inside the boundary, but might also be referenced in hoisted snippets.
 	// to resolve this we cheat: we duplicate const tags inside snippets
@@ -55,6 +56,10 @@ export function SvelteBoundary(node, context) {
 				});
 			}
 		}
+
+		if (child.type === 'DeclarationTag') {
+			has_declaration = true;
+		}
 	}
 
 	for (const child of node.fragment.nodes) {
@@ -68,10 +73,10 @@ export function SvelteBoundary(node, context) {
 		if (child.type === 'SnippetBlock') {
 			if (
 				context.state.options.experimental.async &&
-				has_const &&
+				(has_const || has_declaration) &&
 				!['failed', 'pending'].includes(child.expression.name)
 			) {
-				// we can't hoist snippets as they may reference const tags, so we just keep them in the fragment
+				// we can't hoist snippets as they may reference const/declaration tags, so we just keep them in the fragment
 				nodes.push(child);
 			} else {
 				/** @type {Statement[]} */
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js b/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
index 90a693b99a..24ca58bb41 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
@@ -15,6 +15,7 @@ import { CallExpression } from './visitors/CallExpression.js';
 import { ClassBody } from './visitors/ClassBody.js';
 import { Component } from './visitors/Component.js';
 import { ConstTag } from './visitors/ConstTag.js';
+import { DeclarationTag } from './visitors/DeclarationTag.js';
 import { DebugTag } from './visitors/DebugTag.js';
 import { EachBlock } from './visitors/EachBlock.js';
 import { ExpressionStatement } from './visitors/ExpressionStatement.js';
@@ -64,6 +65,7 @@ const template_visitors = {
 	AwaitBlock,
 	Component,
 	ConstTag,
+	DeclarationTag,
 	DebugTag,
 	EachBlock,
 	Fragment,
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/types.d.ts b/packages/svelte/src/compiler/phases/3-transform/server/types.d.ts
index 4912728a1e..2863955786 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/types.d.ts
+++ b/packages/svelte/src/compiler/phases/3-transform/server/types.d.ts
@@ -28,7 +28,7 @@ export interface ComponentServerTransformState extends ServerTransformState {
 	readonly preserve_whitespace: boolean;
 	/** True if the current node is a) a component or render tag and b) the sole child of a block  */
 	readonly is_standalone: boolean;
-	/** Transformed async `{@const }` declarations (if any) and those coming after them */
+	/** Transformed async `{@const }`/`{let/const ...}` declarations (if any) and those coming after them */
 	async_consts?: {
 		id: Identifier;
 		thunks: Expression[];
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/ConstTag.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/ConstTag.js
index 9420bdd6d2..cf56ef6910 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/ConstTag.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/ConstTag.js
@@ -1,8 +1,9 @@
-/** @import { Expression, Pattern, Statement } from 'estree' */
+/** @import { Expression, Pattern } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types.js' */
 import * as b from '#compiler/builders';
 import { extract_identifiers } from '../../../../utils/ast.js';
+import { add_async_declaration } from './DeclarationTag.js';
 
 /**
  * @param {AST.ConstTag} node
@@ -12,31 +13,15 @@ export function ConstTag(node, context) {
 	const declaration = node.declaration.declarations[0];
 	const id = /** @type {Pattern} */ (context.visit(declaration.id));
 	const init = /** @type {Expression} */ (context.visit(declaration.init));
-	const blockers = [...node.metadata.expression.dependencies]
-		.map((dep) => dep.blocker)
-		.filter((b) => b !== null && b.object !== context.state.async_consts?.id);
 
 	if (node.metadata.promises_id) {
-		const run = (context.state.async_consts ??= {
-			id: node.metadata.promises_id,
-			thunks: []
-		});
-
-		const identifiers = extract_identifiers(declaration.id);
-
-		for (const identifier of identifiers) {
-			context.state.init.push(b.let(identifier.name));
-		}
-
-		if (blockers.length === 1) {
-			run.thunks.push(b.thunk(/** @type {Expression} */ (blockers[0])));
-		} else if (blockers.length > 0) {
-			run.thunks.push(b.thunk(b.call('Promise.all', b.array(blockers))));
-		}
-
-		// keep the number of thunks pushed in sync with ConstTag in analysis phase
-		const assignment = b.assignment('=', id, init);
-		run.thunks.push(b.thunk(assignment, node.metadata.expression.has_await));
+		add_async_declaration(
+			context,
+			node.metadata,
+			extract_identifiers(id),
+			[b.stmt(b.assignment('=', id, init))],
+			'let'
+		);
 	} else {
 		context.state.init.push(b.const(id, init));
 	}
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/DeclarationTag.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/DeclarationTag.js
new file mode 100644
index 0000000000..8338700c0b
--- /dev/null
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/DeclarationTag.js
@@ -0,0 +1,85 @@
+/** @import { Expression, Identifier, Pattern, Statement, ExpressionStatement, VariableDeclaration } from 'estree' */
+/** @import { AST } from '#compiler' */
+/** @import { ComponentContext } from '../types.js' */
+import { extract_identifiers, has_await_expression } from '../../../../utils/ast.js';
+import * as b from '#compiler/builders';
+
+/**
+ * @param {AST.DeclarationTag} node
+ * @param {ComponentContext} context
+ */
+export function DeclarationTag(node, context) {
+	const declaration = /** @type {Statement} */ (context.visit(node.declaration));
+
+	if (
+		node.metadata.promises_id &&
+		node.declaration.type === 'VariableDeclaration' &&
+		declaration.type === 'VariableDeclaration'
+	) {
+		const { ids, assignments } = build_async_declaration_parts(declaration);
+		add_async_declaration(context, node.metadata, ids, assignments, declaration.kind);
+	} else {
+		context.state.init.push(declaration);
+	}
+}
+
+/**
+ * @param {VariableDeclaration} declaration
+ */
+export function build_async_declaration_parts(declaration) {
+	const ids = new Map();
+	for (const declarator of declaration.declarations) {
+		for (const id of extract_identifiers(declarator.id)) {
+			ids.set(id.name, id);
+		}
+	}
+
+	const assignments = declaration.declarations
+		.filter((declarator) => declarator.init !== null)
+		.map((declarator) =>
+			b.stmt(
+				b.assignment(
+					'=',
+					/** @type {Pattern} */ (declarator.id),
+					/** @type {Expression} */ (declarator.init)
+				)
+			)
+		);
+
+	return { ids: [...ids.values()], assignments };
+}
+
+/**
+ * @param {ComponentContext} context
+ * @param {AST.ConstTag['metadata'] | AST.DeclarationTag['metadata']} metadata
+ * @param {Identifier[]} ids
+ * @param {ExpressionStatement[]} assignments
+ * @param {VariableDeclaration['kind']} [kind]
+ */
+export function add_async_declaration(context, metadata, ids, assignments, kind = 'let') {
+	const run = (context.state.async_consts ??= {
+		id: /** @type {Identifier} */ (metadata.promises_id),
+		thunks: []
+	});
+
+	for (const id of ids) {
+		context.state.init.push(kind === 'var' ? b.var(id.name) : b.let(id.name));
+	}
+
+	const blockers = [...metadata.expression.dependencies]
+		.map((dep) => dep.blocker)
+		.filter((b) => b !== null && b.object !== context.state.async_consts?.id);
+
+	if (blockers.length === 1) {
+		run.thunks.push(b.thunk(/** @type {Expression} */ (blockers[0])));
+	} else if (blockers.length > 0) {
+		run.thunks.push(b.thunk(b.call('Promise.all', b.array(blockers))));
+	}
+
+	// keep the number of thunks pushed in sync with analysis phase
+	const has_await =
+		metadata.expression.has_await ||
+		assignments.some((assignment) => has_await_expression(assignment));
+	const body = assignments.length === 1 ? assignments[0].expression : b.block(assignments);
+	run.thunks.push(b.thunk(body, has_await));
+}
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/RegularElement.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/RegularElement.js
index 42d9bcb667..90c34d7035 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/RegularElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/RegularElement.js
@@ -17,17 +17,23 @@ import { is_customizable_select_element } from '../../../nodes.js';
 export function RegularElement(node, context) {
 	const name = context.state.namespace === 'html' ? node.name.toLowerCase() : node.name;
 	const namespace = determine_namespace_for_children(node, context.state.namespace);
+	const has_child_declarations = !node.fragment.metadata.transparent;
 
 	/** @type {ComponentServerTransformState} */
 	const state = {
 		...context.state,
 		namespace,
+		scope: /** @type {Scope} */ (context.state.scopes.get(node.fragment)),
 		preserve_whitespace:
 			context.state.preserve_whitespace || node.name === 'pre' || node.name === 'textarea',
 		init: [],
-		template: []
+		template: [],
+		async_consts: undefined
 	};
 
+	/** @type {ComponentServerTransformState} */
+	const attribute_state = { ...state, scope: context.state.scope };
+
 	const node_is_void = is_void(name);
 
 	const optimiser = new PromiseOptimiser();
@@ -50,7 +56,11 @@ export function RegularElement(node, context) {
 	if (!is_special) {
 		// only open the tag in the non-special path
 		state.template.push(b.literal(`<${name}`));
-		body = build_element_attributes(node, { ...context, state }, optimiser.transform);
+		body = build_element_attributes(
+			node,
+			{ ...context, state: attribute_state },
+			optimiser.transform
+		);
 		state.template.push(b.literal(node_is_void ? '/>' : '>')); // add `/>` for XHTML compliance
 	}
 
@@ -72,10 +82,7 @@ export function RegularElement(node, context) {
 		node.fragment.nodes,
 		context.path,
 		namespace,
-		{
-			...state,
-			scope: /** @type {Scope} */ (state.scopes.get(node.fragment))
-		},
+		state,
 		state.preserve_whitespace,
 		state.options.preserveComments
 	);
@@ -205,7 +212,17 @@ export function RegularElement(node, context) {
 		state.template.push(b.stmt(b.call('$.pop_element')));
 	}
 
-	if (optimiser.is_async()) {
+	if (has_child_declarations && state.async_consts && state.async_consts.thunks.length > 0) {
+		state.init.push(
+			b.var(state.async_consts.id, b.call('$$renderer.run', b.array(state.async_consts.thunks)))
+		);
+	}
+
+	if (has_child_declarations) {
+		context.state.template.push(
+			...optimiser.render([b.block([...state.init, ...build_template(state.template)])])
+		);
+	} else if (optimiser.is_async()) {
 		context.state.template.push(
 			...optimiser.render([...state.init, ...build_template(state.template)])
 		);
diff --git a/packages/svelte/src/compiler/phases/3-transform/utils.js b/packages/svelte/src/compiler/phases/3-transform/utils.js
index f61b59f3bd..c7fce61ff9 100644
--- a/packages/svelte/src/compiler/phases/3-transform/utils.js
+++ b/packages/svelte/src/compiler/phases/3-transform/utils.js
@@ -152,6 +152,7 @@ export function clean_nodes(
 
 		if (
 			node.type === 'ConstTag' ||
+			node.type === 'DeclarationTag' ||
 			node.type === 'DebugTag' ||
 			node.type === 'SvelteBody' ||
 			node.type === 'SvelteWindow' ||
diff --git a/packages/svelte/src/compiler/phases/nodes.js b/packages/svelte/src/compiler/phases/nodes.js
index 48ebacb50b..da7e73015b 100644
--- a/packages/svelte/src/compiler/phases/nodes.js
+++ b/packages/svelte/src/compiler/phases/nodes.js
@@ -217,6 +217,7 @@ function* find_descendants(fragment) {
 			case 'SnippetBlock':
 			case 'DebugTag':
 			case 'ConstTag':
+			case 'DeclarationTag':
 			case 'Comment':
 			case 'ExpressionTag':
 				break;
diff --git a/packages/svelte/src/compiler/print/index.js b/packages/svelte/src/compiler/print/index.js
index c511ee6da0..fbd7e86f12 100644
--- a/packages/svelte/src/compiler/print/index.js
+++ b/packages/svelte/src/compiler/print/index.js
@@ -603,6 +603,48 @@ const svelte_visitors = (comments) => ({
 		context.write('}');
 	},
 
+	DeclarationTag(node, context) {
+		context.write('{');
+
+		// This is duplicated from esrap's handling of VariableDeclaration,
+		// which we need to do in order to omit the trailing semicolon that esrap would add.
+		const open = context.new();
+		const join = context.new();
+		const child_context = context.new();
+
+		context.append(child_context);
+
+		child_context.write(`${node.declaration.kind} `);
+		child_context.append(open);
+
+		const declarations = node.declaration.declarations;
+		let first = true;
+
+		for (const d of declarations) {
+			if (!first) child_context.append(join);
+			first = false;
+
+			child_context.visit(d);
+		}
+
+		const length = child_context.measure() + 2 * (declarations.length - 1);
+
+		const multiline = child_context.multiline || (declarations.length > 1 && length > 50);
+
+		if (multiline) {
+			context.multiline = true;
+
+			if (declarations.length > 1) open.indent();
+			join.write(',');
+			join.newline();
+			if (declarations.length > 1) context.dedent();
+		} else {
+			join.write(', ');
+		}
+
+		context.write('}');
+	},
+
 	DebugTag(node, context) {
 		context.write('{@debug ');
 		let started = false;
diff --git a/packages/svelte/src/compiler/types/template.d.ts b/packages/svelte/src/compiler/types/template.d.ts
index 2964e46761..4d4b6fc21f 100644
--- a/packages/svelte/src/compiler/types/template.d.ts
+++ b/packages/svelte/src/compiler/types/template.d.ts
@@ -160,6 +160,18 @@ export namespace AST {
 		};
 	}
 
+	/** A `{let ...}` or `{const ...}` tag */
+	export interface DeclarationTag extends BaseNode {
+		type: 'DeclarationTag';
+		declaration: VariableDeclaration;
+		/** @internal */
+		metadata: {
+			expression: ExpressionMetadata;
+			/** If this declaration tag contains an await expression, or needs to wait on other async, this is set */
+			promises_id?: Identifier;
+		};
+	}
+
 	/** A `{@debug ...}` tag */
 	export interface DebugTag extends BaseNode {
 		type: 'DebugTag';
@@ -622,6 +634,7 @@ export namespace AST {
 	export type Tag =
 		| AST.AttachTag
 		| AST.ConstTag
+		| AST.DeclarationTag
 		| AST.DebugTag
 		| AST.ExpressionTag
 		| AST.HtmlTag
diff --git a/packages/svelte/tests/parser-modern/samples/loose-declaration-tag/input.svelte b/packages/svelte/tests/parser-modern/samples/loose-declaration-tag/input.svelte
new file mode 100644
index 0000000000..f222531638
--- /dev/null
+++ b/packages/svelte/tests/parser-modern/samples/loose-declaration-tag/input.svelte
@@ -0,0 +1,4 @@
+{#if true}
+	{let }
+	{const x = }
+{/if}
diff --git a/packages/svelte/tests/parser-modern/samples/loose-declaration-tag/output.json b/packages/svelte/tests/parser-modern/samples/loose-declaration-tag/output.json
new file mode 100644
index 0000000000..882e5f34f1
--- /dev/null
+++ b/packages/svelte/tests/parser-modern/samples/loose-declaration-tag/output.json
@@ -0,0 +1,113 @@
+{
+	"css": null,
+	"js": [],
+	"start": 0,
+	"end": 38,
+	"type": "Root",
+	"fragment": {
+		"type": "Fragment",
+		"nodes": [
+			{
+				"type": "IfBlock",
+				"elseif": false,
+				"start": 0,
+				"end": 38,
+				"test": {
+					"type": "Literal",
+					"start": 5,
+					"end": 9,
+					"loc": {
+						"start": {
+							"line": 1,
+							"column": 5
+						},
+						"end": {
+							"line": 1,
+							"column": 9
+						}
+					},
+					"value": true,
+					"raw": "true"
+				},
+				"consequent": {
+					"type": "Fragment",
+					"nodes": [
+						{
+							"type": "Text",
+							"start": 10,
+							"end": 12,
+							"raw": "\n\t",
+							"data": "\n\t"
+						},
+						{
+							"type": "DeclarationTag",
+							"start": 12,
+							"end": 18,
+							"declaration": {
+								"type": "VariableDeclaration",
+								"kind": "let",
+								"declarations": [
+									{
+										"type": "VariableDeclarator",
+										"id": {
+											"type": "Identifier",
+											"name": "",
+											"start": 17,
+											"end": 17
+										},
+										"init": null,
+										"start": 17,
+										"end": 17
+									}
+								],
+								"start": 13,
+								"end": 17
+							}
+						},
+						{
+							"type": "Text",
+							"start": 18,
+							"end": 20,
+							"raw": "\n\t",
+							"data": "\n\t"
+						},
+						{
+							"type": "DeclarationTag",
+							"start": 20,
+							"end": 32,
+							"declaration": {
+								"type": "VariableDeclaration",
+								"kind": "const",
+								"declarations": [
+									{
+										"type": "VariableDeclarator",
+										"id": {
+											"type": "Identifier",
+											"name": "",
+											"start": 31,
+											"end": 31
+										},
+										"init": null,
+										"start": 31,
+										"end": 31
+									}
+								],
+								"start": 21,
+								"end": 31
+							}
+						},
+						{
+							"type": "Text",
+							"start": 32,
+							"end": 33,
+							"raw": "\n",
+							"data": "\n"
+						}
+					]
+				},
+				"alternate": null
+			}
+		]
+	},
+	"options": null
+}
diff --git a/packages/svelte/tests/print/samples/declaration-tag/input.svelte b/packages/svelte/tests/print/samples/declaration-tag/input.svelte
new file mode 100644
index 0000000000..6dbb2af2dd
--- /dev/null
+++ b/packages/svelte/tests/print/samples/declaration-tag/input.svelte
@@ -0,0 +1,7 @@
+{#if visible}
+	{let count = 1}
+	{const doubled = count * 2}
+	{const label = 'count'}
+	{const format = (value) => `${label}: ${value}`}
+	<p>{format(doubled)}</p>
+{/if}
diff --git a/packages/svelte/tests/print/samples/declaration-tag/output.svelte b/packages/svelte/tests/print/samples/declaration-tag/output.svelte
new file mode 100644
index 0000000000..6dbb2af2dd
--- /dev/null
+++ b/packages/svelte/tests/print/samples/declaration-tag/output.svelte
@@ -0,0 +1,7 @@
+{#if visible}
+	{let count = 1}
+	{const doubled = count * 2}
+	{const label = 'count'}
+	{const format = (value) => `${label}: ${value}`}
+	<p>{format(doubled)}</p>
+{/if}
diff --git a/packages/svelte/tests/runtime-runes/samples/async-declaration-tag-2/_config.js b/packages/svelte/tests/runtime-runes/samples/async-declaration-tag-2/_config.js
new file mode 100644
index 0000000000..0dd4b870d5
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-declaration-tag-2/_config.js
@@ -0,0 +1,13 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['async-server', 'client', 'hydrate'],
+	ssrHtml: `<h1>Hello, world!</h1> 5 01234 5 sync 6 5 0 10`,
+
+	async test({ assert, target }) {
+		await tick();
+
+		assert.htmlEqual(target.innerHTML, `<h1>Hello, world!</h1> 5 01234 5 sync 6 5 0 10`);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-declaration-tag-2/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-declaration-tag-2/main.svelte
new file mode 100644
index 0000000000..f15065e4db
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-declaration-tag-2/main.svelte
@@ -0,0 +1,31 @@
+<script>
+	let name = $state('world');
+</script>
+
+<svelte:boundary>
+	{const sync = 'sync'}
+	{const number = await Promise.resolve(5)}
+	{const after_async =number + 1}
+	{const { length, 0: first } = await '01234'}
+
+	{#snippet greet()}
+		{const greeting = $derived(await `Hello, ${name}!`)}
+		<h1>{greeting}</h1>
+		{number}
+		{#if number > 4 && after_async && greeting}
+			{const length = $derived(await number)}
+			{#each { length }, index}
+				{const i = $derived(await index)}
+				{i}
+			{/each}
+		{/if}
+	{/snippet}
+
+	{@render greet()}
+	{number} {sync} {after_async} {length} {first}
+
+	{#if sync}
+		{const double = $derived(number * 2)}
+		{double}
+	{/if}
+</svelte:boundary>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-declaration-tag/_config.js b/packages/svelte/tests/runtime-runes/samples/async-declaration-tag/_config.js
new file mode 100644
index 0000000000..8fd2fc0976
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-declaration-tag/_config.js
@@ -0,0 +1,43 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		await tick();
+		const [top, change] = target.querySelectorAll('button');
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+			<button>name</button>
+			<button>change name</button>
+			<p>Hello name</p>
+			<div><span>nested Hi name</span></div>
+		`
+		);
+
+		top.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+			<button>other</button>
+			<button>change name</button>
+			<p>Hello name</p>
+			<div><span>nested Hi name</span></div>
+		`
+		);
+
+		change.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+			<button>other</button>
+			<button>change name</button>
+			<p>Hello other</p>
+			<div><span>nested Hi other</span></div>
+		`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-declaration-tag/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-declaration-tag/main.svelte
new file mode 100644
index 0000000000..4521ea2e41
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-declaration-tag/main.svelte
@@ -0,0 +1,20 @@
+<script>
+	const id = 'name';
+	const top_id = await 'name';
+</script>
+
+{let name = $state(top_id)}
+<button onclick={() => name = 'other'}>{name}</button>
+
+{#if id}
+	{let name = $state(await id)}
+	{let greeting = $derived(await `Hello ${name}`)}
+
+	<button onclick={() => name = 'other'}>change name</button>
+	<p>{greeting}</p>
+	<div>
+		{const nested = 'nested'}
+		{const greeting2 = $derived(await `Hi ${name}`)}
+		<span>{nested} {greeting2}</span>
+	</div>
+{/if}
diff --git a/packages/svelte/tests/runtime-runes/samples/declaration-tags-no-script/_config.js b/packages/svelte/tests/runtime-runes/samples/declaration-tags-no-script/_config.js
new file mode 100644
index 0000000000..901df42df7
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/declaration-tags-no-script/_config.js
@@ -0,0 +1,13 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	html: '<button>0 | 0</button>',
+	async test({ assert, target }) {
+		const [increment] = target.querySelectorAll('button');
+
+		increment.click();
+		await tick();
+		assert.htmlEqual(target.innerHTML, '<button>1 | 2</button>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/declaration-tags-no-script/main.svelte b/packages/svelte/tests/runtime-runes/samples/declaration-tags-no-script/main.svelte
new file mode 100644
index 0000000000..da72bc69c6
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/declaration-tags-no-script/main.svelte
@@ -0,0 +1,3 @@
+{let count = $state(0)}
+{let doubled = $derived(count * 2)}
+<button onclick={() => (count += 1)}>{count} | {doubled}</button>
diff --git a/packages/svelte/tests/runtime-runes/samples/declaration-tags/_config.js b/packages/svelte/tests/runtime-runes/samples/declaration-tags/_config.js
new file mode 100644
index 0000000000..54e390ec83
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/declaration-tags/_config.js
@@ -0,0 +1,37 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	html: `<button>top 2</button><button>toggle</button><button>2</button><p>4 total</p><div><span>nested</span></div><div><span>nested</span></div>`,
+	async test({ assert, target }) {
+		const [top, toggle, increment] = target.querySelectorAll('button');
+
+		top.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`<button>top 4</button><button>toggle</button><button>2</button><p>4 total</p><div><span>nested</span></div><div><span>nested</span></div>`
+		);
+
+		increment.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`<button>top 4</button><button>toggle</button><button>3</button><p>6 total</p><div><span>nested</span></div><div><span>nested</span></div>`
+		);
+
+		toggle.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`<button>top 4</button><button>toggle</button><div><span>nested</span></div>`
+		);
+
+		toggle.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`<button>top 4</button><button>toggle</button><button>2</button><p>4 total</p><div><span>nested</span></div><div><span>nested</span></div>`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/declaration-tags/main.svelte b/packages/svelte/tests/runtime-runes/samples/declaration-tags/main.svelte
new file mode 100644
index 0000000000..5953104092
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/declaration-tags/main.svelte
@@ -0,0 +1,29 @@
+<script>
+	let visible = $state(true);
+	let initial = $state(2);
+</script>
+
+{let top = $state(1)}
+{let top_doubled = $derived(top * 2)}
+
+<button onclick={() => (top += 1)}>top {top_doubled}</button>
+<button onclick={() => (visible = !visible)}>toggle</button>
+
+{#if visible}
+	{let counter = $state({ value: initial })}
+	{let doubled = $derived(counter.value * 2)}
+	{const suffix = ' total'}
+	{const format = (value) => `${value}${suffix}`}
+
+	<button onclick={() => (counter.value += 1)}>{counter.value}</button>
+	<p>{format(doubled)}</p>
+	<div>
+		{const doubled = 'nested'}
+		<span>{doubled}</span>
+	</div>
+{/if}
+
+<div>
+	{const nested = 'nested'}
+	<span>{nested}</span>
+</div>
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-invalid-function/errors.json b/packages/svelte/tests/validator/samples/declaration-tag-invalid-function/errors.json
new file mode 100644
index 0000000000..bf0266225f
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/declaration-tag-invalid-function/errors.json
@@ -0,0 +1,14 @@
+[
+	{
+		"code": "declaration_tag_invalid_type",
+		"message": "Declaration tags must be `let` or `const` declarations",
+		"start": {
+			"line": 2,
+			"column": 2
+		},
+		"end": {
+			"line": 2,
+			"column": 10
+		}
+	}
+]
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-invalid-function/input.svelte b/packages/svelte/tests/validator/samples/declaration-tag-invalid-function/input.svelte
new file mode 100644
index 0000000000..8cfdf59c0f
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/declaration-tag-invalid-function/input.svelte
@@ -0,0 +1,3 @@
+{#if true}
+	{function foo() {}}
+{/if}
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-invalid-type/errors.json b/packages/svelte/tests/validator/samples/declaration-tag-invalid-type/errors.json
new file mode 100644
index 0000000000..2a9b3c0140
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/declaration-tag-invalid-type/errors.json
@@ -0,0 +1,14 @@
+[
+	{
+		"code": "declaration_tag_invalid_type",
+		"message": "Declaration tags must be `let` or `const` declarations",
+		"start": {
+			"line": 2,
+			"column": 2
+		},
+		"end": {
+			"line": 2,
+			"column": 5
+		}
+	}
+]
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-invalid-type/input.svelte b/packages/svelte/tests/validator/samples/declaration-tag-invalid-type/input.svelte
new file mode 100644
index 0000000000..eb9fcd5e75
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/declaration-tag-invalid-type/input.svelte
@@ -0,0 +1,3 @@
+{#if true}
+	{var foo = 1}
+{/if}
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-legacy-mode/errors.json b/packages/svelte/tests/validator/samples/declaration-tag-legacy-mode/errors.json
new file mode 100644
index 0000000000..6b89f2eab8
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/declaration-tag-legacy-mode/errors.json
@@ -0,0 +1,14 @@
+[
+	{
+		"code": "declaration_tag_no_legacy_mode",
+		"message": "Declaration tags cannot be used in legacy mode",
+		"start": {
+			"line": 5,
+			"column": 0
+		},
+		"end": {
+			"line": 5,
+			"column": 19
+		}
+	}
+]
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-legacy-mode/input.svelte b/packages/svelte/tests/validator/samples/declaration-tag-legacy-mode/input.svelte
new file mode 100644
index 0000000000..026d4eff1e
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/declaration-tag-legacy-mode/input.svelte
@@ -0,0 +1,5 @@
+<script>
+	export let name = 'world';
+</script>
+
+{const foo = 'foo'}
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-maybe-runes/errors.json b/packages/svelte/tests/validator/samples/declaration-tag-maybe-runes/errors.json
new file mode 100644
index 0000000000..fe51488c70
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/declaration-tag-maybe-runes/errors.json
@@ -0,0 +1 @@
+[]
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-maybe-runes/input.svelte b/packages/svelte/tests/validator/samples/declaration-tag-maybe-runes/input.svelte
new file mode 100644
index 0000000000..081f242a81
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/declaration-tag-maybe-runes/input.svelte
@@ -0,0 +1,6 @@
+<script>
+	let name = 'world';
+</script>
+
+Usage when no explicit runes/legacy mode should be ok
+{const foo = world}
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index 3f71d44177..1c3795be80 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -1303,6 +1303,12 @@ declare module 'svelte/compiler' {
 			};
 		}
 
+		/** A `{let ...}` or `{const ...}` tag */
+		export interface DeclarationTag extends BaseNode {
+			type: 'DeclarationTag';
+			declaration: VariableDeclaration;
+		}
+
 		/** A `{@debug ...}` tag */
 		export interface DebugTag extends BaseNode {
 			type: 'DebugTag';
@@ -1613,6 +1619,7 @@ declare module 'svelte/compiler' {
 		export type Tag =
 			| AST.AttachTag
 			| AST.ConstTag
+			| AST.DeclarationTag
 			| AST.DebugTag
 			| AST.ExpressionTag
 			| AST.HtmlTag

From 5300843e8683948e15eebe8b3342cdef6614a41d Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 29 May 2026 09:28:27 -0400
Subject: [PATCH 055/222] chore: bump playwright (#18319)

hopefully this will fix the CI timeouts
---
 .github/workflows/ci.yml     |  2 +-
 package.json                 |  2 +-
 packages/svelte/package.json |  6 +--
 pnpm-lock.yaml               | 72 +++++++++++++++++++++---------------
 4 files changed, 47 insertions(+), 35 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c25e191702..7eff1b9fe7 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -80,7 +80,7 @@ jobs:
   Lint:
     permissions: {}
     runs-on: ubuntu-latest
-    timeout-minutes: 5
+    timeout-minutes: 10
     steps:
       - uses: actions/checkout@v6
       - uses: pnpm/action-setup@fc06bc1257f339d1d5d8b3a19a8cae5388b55320 # v4
diff --git a/package.json b/package.json
index 34079f43cf..f741ec3e1f 100644
--- a/package.json
+++ b/package.json
@@ -37,7 +37,7 @@
     "eslint-plugin-lube": "^0.5.1",
     "eslint-plugin-svelte": "^3.15.0",
     "jsdom": "25.0.1",
-    "playwright": "^1.58.0",
+    "playwright": "^1.60.0",
     "prettier": "^3.2.4",
     "prettier-plugin-svelte": "^3.4.0",
     "svelte": "workspace:^",
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 5e3bb5e031..713c7c04c0 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -152,7 +152,7 @@
   },
   "devDependencies": {
     "@jridgewell/trace-mapping": "^0.3.25",
-    "@playwright/test": "^1.58.0",
+    "@playwright/test": "^1.60.0",
     "@rollup/plugin-commonjs": "^28.0.1",
     "@rollup/plugin-node-resolve": "^15.3.0",
     "@rollup/plugin-terser": "^0.4.4",
@@ -162,12 +162,12 @@
     "baseline-browser-mapping": "^2.10.32",
     "dts-buddy": "^0.5.5",
     "esbuild": "^0.25.10",
-    "web-features": "^3.29.0",
     "rollup": "^4.59.0",
     "source-map": "^0.7.4",
     "tinyglobby": "^0.2.12",
     "typescript": "^5.5.4",
-    "vitest": "^2.1.9"
+    "vitest": "^2.1.9",
+    "web-features": "^3.29.0"
   },
   "dependencies": {
     "@jridgewell/remapping": "^2.3.4",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 4c077f0f6b..767af0515a 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -42,8 +42,8 @@ importers:
         specifier: 25.0.1
         version: 25.0.1
       playwright:
-        specifier: ^1.58.0
-        version: 1.58.0
+        specifier: ^1.60.0
+        version: 1.60.0
       prettier:
         specifier: ^3.2.4
         version: 3.2.4
@@ -121,8 +121,8 @@ importers:
         specifier: ^0.3.25
         version: 0.3.31
       '@playwright/test':
-        specifier: ^1.58.0
-        version: 1.58.0
+        specifier: ^1.60.0
+        version: 1.60.0
       '@rollup/plugin-commonjs':
         specifier: ^28.0.1
         version: 28.0.1(rollup@4.60.1)
@@ -864,8 +864,8 @@ packages:
     resolution: {integrity: sha512-+1VkjdD0QBLPodGrJUeqarH8VAIvQODIbwh9XpP5Syisf7YoQgsJKPNFoqqLQlu+VQ/tVSshMR6loPMn8U+dPg==}
     engines: {node: '>=14'}
 
-  '@playwright/test@1.58.0':
-    resolution: {integrity: sha512-fWza+Lpbj6SkQKCrU6si4iu+fD2dD3gxNHFhUPxsfXBPhnv3rRSQVd0NtBUT9Z/RhF/boCBcuUaMUSTRTopjZg==}
+  '@playwright/test@1.60.0':
+    resolution: {integrity: sha512-O71yZIbAh/PxDMNGns37GHBIfrVkEVyn+AXyIa5dOTfb4/xNvRWV+Vv/NMbNCtODB/pO7vLlF2OTmMVLhmr7Ag==}
     engines: {node: '>=18'}
     hasBin: true
 
@@ -1096,6 +1096,9 @@ packages:
   '@types/estree@1.0.8':
     resolution: {integrity: sha512-dWHzHa2WqEXI/O1E9OjrocMTKJl2mSrEolh1Iomrv6U+JuNwaHXsXx9bLu5gG7BUWFIN0skIQJQ/L1rIex4X6w==}
 
+  '@types/estree@1.0.9':
+    resolution: {integrity: sha512-GhdPgy1el4/ImP05X05Uw4cw2/M93BCUmnEvWZNStlCzEKME4Fkk+YpoA5OiHNQmoS7Cafb8Xa3Pya8m1Qrzeg==}
+
   '@types/json-schema@7.0.15':
     resolution: {integrity: sha512-5+fP8P8MFNC+AyZCDxrB2pkZFPGzqQWUzpSeuuVLvm8VMcorNYavBqoFcxK8bQz4Qsbn4oUEEem4wDLfcysGHA==}
 
@@ -1459,8 +1462,8 @@ packages:
   emoji-regex@9.2.2:
     resolution: {integrity: sha512-L18DaJsXSUk2+42pv8mLs5jJT2hqFkFE4j21wOmgbUqsZ2hL72NsUU785g9RXgo3s0ZNgVl42TiHp3ZtOv/Vyg==}
 
-  enhanced-resolve@5.20.1:
-    resolution: {integrity: sha512-Qohcme7V1inbAfvjItgw0EaxVX5q2rdVEZHRBrEQdRZTssLDGsL8Lwrznl8oQ/6kuTJONLaDcGjkNP247XEhcA==}
+  enhanced-resolve@5.22.1:
+    resolution: {integrity: sha512-6QEuw3zoX1SJQc7b87aBXke/no+mG2bTBgw29gWMQonLmpEkWoCAVkl+M49e48AZlWzxiDzDZzYdp6kobcyLww==}
     engines: {node: '>=10.13.0'}
 
   enquirer@2.4.1:
@@ -1699,8 +1702,8 @@ packages:
   function-bind@1.1.2:
     resolution: {integrity: sha512-7XHNxH7qX9xG5mIwxkhumTox/MIRNcOgDrxWsMt2pAr23WHp6MrRlN7FBSFpCpr+oVO0F744iUgR82nJMfG2SA==}
 
-  get-tsconfig@4.13.7:
-    resolution: {integrity: sha512-7tN6rFgBlMgpBML5j8typ92BKFi2sFQvIdpAqLA2beia5avZDrMs0FLZiM5etShWq5irVyGcGMEA1jcDaK7A/Q==}
+  get-tsconfig@4.14.0:
+    resolution: {integrity: sha512-yTb+8DXzDREzgvYmh6s9vHsSVCHeC0G3PI5bEXNBHtmshPnO+S5O7qgLEOn0I5QvMy6kpZN8K1NKGyilLb93wA==}
 
   glob-parent@5.1.2:
     resolution: {integrity: sha512-AOIgSQCepiJYwP3ARnGx+5VnTu2HBYdzbGP45eLw1vr3zB3vZLeyed1sC9hnbcOc9/SrMyM5RPQrkGz4aS9Zow==}
@@ -2162,13 +2165,13 @@ packages:
     resolution: {integrity: sha512-uB80kBFb/tfd68bVleG9T5GGsGPjJrLAUpR5PZIrhBnIaRTQRjqdJSsIKkOP6OAIFbj7GOrcudc5pNjZ+geV2g==}
     engines: {node: '>=6'}
 
-  playwright-core@1.58.0:
-    resolution: {integrity: sha512-aaoB1RWrdNi3//rOeKuMiS65UCcgOVljU46At6eFcOFPFHWtd2weHRRow6z/n+Lec0Lvu0k9ZPKJSjPugikirw==}
+  playwright-core@1.60.0:
+    resolution: {integrity: sha512-9bW6zvX/m0lEbgTKJ6YppOKx8H3VOPBMOCFh2irXFOT4BbHgrx5hPjwJYLT40Lu+4qtD36qKc/Hn56StUW57IA==}
     engines: {node: '>=18'}
     hasBin: true
 
-  playwright@1.58.0:
-    resolution: {integrity: sha512-2SVA0sbPktiIY/MCOPX8e86ehA/e+tDNq+e5Y8qjKYti2Z/JG7xnronT/TXTIkKbYGWlCbuucZ6dziEgkoEjQQ==}
+  playwright@1.60.0:
+    resolution: {integrity: sha512-hheHdokM8cdqCb0lcE3s+zT4t4W+vvjpGxsZlDnikarzx8tSzMebh3UiFtgqwFwnTnjYQcsyMF8ei2mCO/tpeA==}
     engines: {node: '>=18'}
     hasBin: true
 
@@ -2307,6 +2310,11 @@ packages:
     engines: {node: '>=10'}
     hasBin: true
 
+  semver@7.8.1:
+    resolution: {integrity: sha512-rkVq3IXh+4FDGch+KwzX3aV9W3kO54GyEgpvBzSyctDA6Xtd7RJQV1xmXbeQp5v7+VzLOfVqiutSE6GICgPFvg==}
+    engines: {node: '>=10'}
+    hasBin: true
+
   serialize-javascript@6.0.2:
     resolution: {integrity: sha512-Saa1xPByTTq2gdeFZYLLo+RFE35NHZkAbqZeWNd3BpzppeVisAqpDjcp8dyf6uIvEqJRd46jemmyA4iFIeVk8g==}
 
@@ -2403,8 +2411,8 @@ packages:
   symbol-tree@3.2.4:
     resolution: {integrity: sha512-9QNk5KwDF+Bvz+PyObkmSYjI5ksVUYtjW7AU22r2NKcfLJcXp96hkDWU3+XndOsUb+AQ9QhfzfCT2O+CNWT5Tw==}
 
-  tapable@2.3.2:
-    resolution: {integrity: sha512-1MOpMXuhGzGL5TTCZFItxCc0AARf1EZFQkGqMm7ERKj8+Hgr5oLvJOVFcC+lRmR8hCe2S3jC4T5D7Vg/d7/fhA==}
+  tapable@2.3.3:
+    resolution: {integrity: sha512-uxc/zpqFg6x7C8vOE7lh6Lbda8eEL9zmVm/PLeTPBRhh1xCgdWaQ+J1CUieGpIfm2HdtsUpRv+HshiasBMcc6A==}
     engines: {node: '>=6'}
 
   term-size@2.2.1:
@@ -3283,9 +3291,9 @@ snapshots:
   '@pkgjs/parseargs@0.11.0':
     optional: true
 
-  '@playwright/test@1.58.0':
+  '@playwright/test@1.60.0':
     dependencies:
-      playwright: 1.58.0
+      playwright: 1.60.0
 
   '@polka/url@1.0.0-next.25': {}
 
@@ -3463,13 +3471,15 @@ snapshots:
 
   '@types/eslint@8.56.12':
     dependencies:
-      '@types/estree': 1.0.8
+      '@types/estree': 1.0.9
       '@types/json-schema': 7.0.15
 
   '@types/esrecurse@4.3.1': {}
 
   '@types/estree@1.0.8': {}
 
+  '@types/estree@1.0.9': {}
+
   '@types/json-schema@7.0.15': {}
 
   '@types/node@12.20.55': {}
@@ -3840,10 +3850,10 @@ snapshots:
 
   emoji-regex@9.2.2: {}
 
-  enhanced-resolve@5.20.1:
+  enhanced-resolve@5.22.1:
     dependencies:
       graceful-fs: 4.2.11
-      tapable: 2.3.2
+      tapable: 2.3.3
 
   enquirer@2.4.1:
     dependencies:
@@ -3945,7 +3955,7 @@ snapshots:
   eslint-compat-utils@0.5.1(eslint@10.0.0):
     dependencies:
       eslint: 10.0.0
-      semver: 7.7.4
+      semver: 7.8.1
 
   eslint-config-prettier@9.1.0(eslint@10.0.0):
     dependencies:
@@ -3965,14 +3975,14 @@ snapshots:
   eslint-plugin-n@17.24.0(eslint@10.0.0)(typescript@5.5.4):
     dependencies:
       '@eslint-community/eslint-utils': 4.9.1(eslint@10.0.0)
-      enhanced-resolve: 5.20.1
+      enhanced-resolve: 5.22.1
       eslint: 10.0.0
       eslint-plugin-es-x: 7.8.0(eslint@10.0.0)
-      get-tsconfig: 4.13.7
+      get-tsconfig: 4.14.0
       globals: 15.15.0
       globrex: 0.1.2
       ignore: 5.3.2
-      semver: 7.7.4
+      semver: 7.8.1
       ts-declaration-location: 1.0.7(typescript@5.5.4)
     transitivePeerDependencies:
       - typescript
@@ -4176,7 +4186,7 @@ snapshots:
 
   function-bind@1.1.2: {}
 
-  get-tsconfig@4.13.7:
+  get-tsconfig@4.14.0:
     dependencies:
       resolve-pkg-maps: 1.0.0
 
@@ -4596,11 +4606,11 @@ snapshots:
 
   pify@4.0.1: {}
 
-  playwright-core@1.58.0: {}
+  playwright-core@1.60.0: {}
 
-  playwright@1.58.0:
+  playwright@1.60.0:
     dependencies:
-      playwright-core: 1.58.0
+      playwright-core: 1.60.0
     optionalDependencies:
       fsevents: 2.3.2
 
@@ -4742,6 +4752,8 @@ snapshots:
 
   semver@7.7.4: {}
 
+  semver@7.8.1: {}
+
   serialize-javascript@6.0.2:
     dependencies:
       randombytes: 2.1.0
@@ -4829,7 +4841,7 @@ snapshots:
 
   symbol-tree@3.2.4: {}
 
-  tapable@2.3.2: {}
+  tapable@2.3.3: {}
 
   term-size@2.2.1: {}
 

From 980c7e2321b5e9041e868c7d32de7029631a3650 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Fri, 29 May 2026 21:51:33 +0200
Subject: [PATCH 056/222] fix: don't error on `{type}` in declaration tags
 (#18321)

The `\b` in the regex matched on `}`, too, so you would get a very
confusing "invalid declaration tag" error on `{type}`. Match on
whitespace instead (because that's what has to come afterwards)

---------

Co-authored-by: vercel[bot] <35613825+vercel[bot]@users.noreply.github.com>
Co-authored-by: Vercel <vercel[bot]@users.noreply.github.com>
Co-authored-by: Rich-Harris <hello@rich-harris.dev>
---
 .../src/compiler/phases/1-parse/state/tag.js      |  5 ++++-
 .../declaration-tag-invalid-type-2/errors.json    | 14 ++++++++++++++
 .../declaration-tag-invalid-type-2/input.svelte   | 15 +++++++++++++++
 3 files changed, 33 insertions(+), 1 deletion(-)
 create mode 100644 packages/svelte/tests/validator/samples/declaration-tag-invalid-type-2/errors.json
 create mode 100644 packages/svelte/tests/validator/samples/declaration-tag-invalid-type-2/input.svelte

diff --git a/packages/svelte/src/compiler/phases/1-parse/state/tag.js b/packages/svelte/src/compiler/phases/1-parse/state/tag.js
index 7428c8660c..45d0081707 100644
--- a/packages/svelte/src/compiler/phases/1-parse/state/tag.js
+++ b/packages/svelte/src/compiler/phases/1-parse/state/tag.js
@@ -12,7 +12,10 @@ import { find_matching_bracket, match_bracket } from '../utils/bracket.js';
 
 const regex_whitespace_with_closing_curly_brace = /\s*}/y;
 const regex_supported_declaration = /(?:let|const)\b/y;
-const regex_unsupported_declaration = /(?:var|function|class|type|interface|enum)\b/y;
+// All except `type` are reserved keywords and cannot be used as variable names.
+// For type we check if it's not something like `type .x` / `type ()` / `type % 2` / ...
+const regex_unsupported_declaration =
+	/(?:(?:var|function|class|interface|enum)\b)|(?:type\s+[^?.(`<[&|%^}])/y;
 
 const pointy_bois = { '<': '>' };
 
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-invalid-type-2/errors.json b/packages/svelte/tests/validator/samples/declaration-tag-invalid-type-2/errors.json
new file mode 100644
index 0000000000..052636cddb
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/declaration-tag-invalid-type-2/errors.json
@@ -0,0 +1,14 @@
+[
+	{
+		"code": "declaration_tag_invalid_type",
+		"message": "Declaration tags must be `let` or `const` declarations",
+		"start": {
+			"line": 14,
+			"column": 2
+		},
+		"end": {
+			"line": 14,
+			"column": 8
+		}
+	}
+]
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-invalid-type-2/input.svelte b/packages/svelte/tests/validator/samples/declaration-tag-invalid-type-2/input.svelte
new file mode 100644
index 0000000000..129a8ac7ba
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/declaration-tag-invalid-type-2/input.svelte
@@ -0,0 +1,15 @@
+{#if true}
+	<!-- check that these doesn't trigger already -->
+	{type}
+	{type }
+	{type && foo}
+	{type || bar}
+	{type % 2}
+	{type .x}
+	{type ?.x}
+	{type ()}
+	{type [1]}
+	{type `tag`}
+	<!-- ... this one should trigger though -->
+	{type foo = boolean}
+{/if}

From a40c745fd95e855a7c667b24ee6bb149783d1813 Mon Sep 17 00:00:00 2001
From: Mathias Picker <48158184+MathiasWP@users.noreply.github.com>
Date: Fri, 29 May 2026 21:55:07 +0200
Subject: [PATCH 057/222] perf: hoist rest_props exclude list as a module-scope
 Set (#18252)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The compiler emitted an inline string array as the second argument to
`$.rest_props(...)`, and the runtime did a linear
`Array.prototype.includes` on it on every property access via the
rest-props Proxy.

The exclude list only depends on the component definition, not on the
instance, so it can be hoisted to module scope and shared by every
instance. Switching it to a `Set` at the same time makes each lookup
O(1).

For a component like `<Button ...rest />` rendered N times, this turns
one per-instance allocation (plus a linear search on every rest-prop
access) into one module-scope allocation plus O(1) lookups.

The legacy `$$restProps` path is unchanged — it mutates the exclude list
in its `deleteProperty` trap, so it can't share a hoisted Set across
instances.

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/hoist-rest-excludes.md                  |  5 +++++
 .../client/visitors/VariableDeclaration.js         | 14 ++++++++++++--
 packages/svelte/src/compiler/utils/builders.js     |  3 ++-
 .../svelte/src/internal/client/reactivity/props.js | 12 ++++++------
 .../_expected/client/index.svelte.js               |  4 +++-
 5 files changed, 28 insertions(+), 10 deletions(-)
 create mode 100644 .changeset/hoist-rest-excludes.md

diff --git a/.changeset/hoist-rest-excludes.md b/.changeset/hoist-rest-excludes.md
new file mode 100644
index 0000000000..52efb06092
--- /dev/null
+++ b/.changeset/hoist-rest-excludes.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+perf: hoist `rest_props` exclude list as a module-scope `Set`
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
index 72685a8e83..b9f4690179 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
@@ -49,8 +49,13 @@ export function VariableDeclaration(node, context) {
 				}
 
 				if (declarator.id.type === 'Identifier') {
+					const exclude_id = context.state.scope.root.unique('rest_excludes');
+					context.state.hoisted.push(
+						b.var(exclude_id, b.new('Set', b.array(seen.map((name) => b.literal(name)))))
+					);
+
 					/** @type {Expression[]} */
-					const args = [b.id('$$props'), b.array(seen.map((name) => b.literal(name)))];
+					const args = [b.id('$$props'), exclude_id];
 
 					if (dev) {
 						// include rest name, so we can provide informative error messages
@@ -95,8 +100,13 @@ export function VariableDeclaration(node, context) {
 							}
 						} else {
 							// RestElement
+							const exclude_id = context.state.scope.root.unique('rest_excludes');
+							context.state.hoisted.push(
+								b.var(exclude_id, b.new('Set', b.array(seen.map((name) => b.literal(name)))))
+							);
+
 							/** @type {Expression[]} */
-							const args = [b.id('$$props'), b.array(seen.map((name) => b.literal(name)))];
+							const args = [b.id('$$props'), exclude_id];
 
 							if (dev) {
 								// include rest name, so we can provide informative error messages
diff --git a/packages/svelte/src/compiler/utils/builders.js b/packages/svelte/src/compiler/utils/builders.js
index 7508caf3e7..1f48f7fd8b 100644
--- a/packages/svelte/src/compiler/utils/builders.js
+++ b/packages/svelte/src/compiler/utils/builders.js
@@ -686,7 +686,8 @@ export {
 	if_builder as if,
 	this_instance as this,
 	null_instance as null,
-	debugger_builder as debugger
+	debugger_builder as debugger,
+	new_builder as new
 };
 
 /**
diff --git a/packages/svelte/src/internal/client/reactivity/props.js b/packages/svelte/src/internal/client/reactivity/props.js
index 5626639a84..c2f3698809 100644
--- a/packages/svelte/src/internal/client/reactivity/props.js
+++ b/packages/svelte/src/internal/client/reactivity/props.js
@@ -49,11 +49,11 @@ export function update_pre_prop(fn, d = 1) {
 /**
  * The proxy handler for rest props (i.e. `const { x, ...rest } = $props()`).
  * Is passed the full `$$props` object and excludes the named props.
- * @type {ProxyHandler<{ props: Record<string | symbol, unknown>, exclude: Array<string | symbol>, name?: string }>}}
+ * @type {ProxyHandler<{ props: Record<string | symbol, unknown>, exclude: Set<string | symbol>, name?: string }>}}
  */
 const rest_props_handler = {
 	get(target, key) {
-		if (target.exclude.includes(key)) return;
+		if (target.exclude.has(key)) return;
 		return target.props[key];
 	},
 	set(target, key) {
@@ -65,7 +65,7 @@ const rest_props_handler = {
 		return false;
 	},
 	getOwnPropertyDescriptor(target, key) {
-		if (target.exclude.includes(key)) return;
+		if (target.exclude.has(key)) return;
 		if (key in target.props) {
 			return {
 				enumerable: true,
@@ -75,17 +75,17 @@ const rest_props_handler = {
 		}
 	},
 	has(target, key) {
-		if (target.exclude.includes(key)) return false;
+		if (target.exclude.has(key)) return false;
 		return key in target.props;
 	},
 	ownKeys(target) {
-		return Reflect.ownKeys(target.props).filter((key) => !target.exclude.includes(key));
+		return Reflect.ownKeys(target.props).filter((key) => !target.exclude.has(key));
 	}
 };
 
 /**
  * @param {Record<string, unknown>} props
- * @param {string[]} exclude
+ * @param {Set<string>} exclude
  * @param {string} [name]
  * @returns {Record<string, unknown>}
  */
diff --git a/packages/svelte/tests/snapshot/samples/props-identifier/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/props-identifier/_expected/client/index.svelte.js
index 5a46b9bbef..7df616f694 100644
--- a/packages/svelte/tests/snapshot/samples/props-identifier/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/props-identifier/_expected/client/index.svelte.js
@@ -1,10 +1,12 @@
 import 'svelte/internal/disclose-version';
 import * as $ from 'svelte/internal/client';
 
+var rest_excludes = new Set(['$$slots', '$$events', '$$legacy']);
+
 export default function Props_identifier($$anchor, $$props) {
 	$.push($$props, true);
 
-	let props = $.rest_props($$props, ['$$slots', '$$events', '$$legacy']);
+	let props = $.rest_props($$props, rest_excludes);
 
 	$$props.a;
 	props[a];

From 2fae91af6de9e526346ee096cef798bd54d2f7fd Mon Sep 17 00:00:00 2001
From: Mathias Picker <48158184+MathiasWP@users.noreply.github.com>
Date: Fri, 29 May 2026 21:58:58 +0200
Subject: [PATCH 058/222] perf: deduplicate identical hoisted templates within
 a component (#18320)

Byte-identical templates hoisted from different fragments, elements, or
branches now share a single `$.from_html` factory instead of each
emitting its own module-scope variable - this shrinks generated output
and avoids redundant runtime template parsing. Dedup is keyed on
`(content, flags)` and is skipped in dev mode (templates there are
wrapped in `$.add_locations`, which embeds per-call-site info).

### Before submitting the PR, please make sure you do the following

- [ ] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).

### Tests and linting

- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/dedupe-hoisted-templates.md        |  5 ++
 .../3-transform/client/transform-client.js    |  1 +
 .../client/transform-template/index.js        | 43 ++++++++++-
 .../phases/3-transform/client/types.d.ts      |  2 +
 .../3-transform/client/visitors/Fragment.js   |  7 +-
 .../client/visitors/RegularElement.js         |  6 +-
 .../_expected/client/index.svelte.js          |  4 +-
 .../_expected/client/index.svelte.js          | 44 +++++++++++
 .../_expected/server/index.svelte.js          | 24 ++++++
 .../samples/dedupe-templates/index.svelte     | 14 ++++
 .../_expected/client/index.svelte.js          |  4 +-
 .../_expected/client/index.svelte.js          |  4 +-
 .../_expected/client/index.svelte.js          | 76 ++++++++-----------
 13 files changed, 172 insertions(+), 62 deletions(-)
 create mode 100644 .changeset/dedupe-hoisted-templates.md
 create mode 100644 packages/svelte/tests/snapshot/samples/dedupe-templates/_expected/client/index.svelte.js
 create mode 100644 packages/svelte/tests/snapshot/samples/dedupe-templates/_expected/server/index.svelte.js
 create mode 100644 packages/svelte/tests/snapshot/samples/dedupe-templates/index.svelte

diff --git a/.changeset/dedupe-hoisted-templates.md b/.changeset/dedupe-hoisted-templates.md
new file mode 100644
index 0000000000..a91882f525
--- /dev/null
+++ b/.changeset/dedupe-hoisted-templates.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+perf: deduplicate identical hoisted templates within a component
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js b/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js
index 6a71a49601..552fe89960 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js
@@ -141,6 +141,7 @@ export function client_component(analysis, options) {
 		scopes: analysis.module.scopes,
 		is_instance: false,
 		hoisted: [b.import_all('$', 'svelte/internal/client'), ...analysis.instance_body.hoisted],
+		templates: new Map(),
 		node: /** @type {any} */ (null), // populated by the root node
 		legacy_reactive_imports: [],
 		legacy_reactive_statements: new Map(),
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/transform-template/index.js b/packages/svelte/src/compiler/phases/3-transform/client/transform-template/index.js
index 40c0907e38..5fdc88844b 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/transform-template/index.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/transform-template/index.js
@@ -1,3 +1,4 @@
+/** @import { TemplateLiteral } from 'estree' */
 /** @import { Namespace } from '#compiler' */
 /** @import { ComponentClientTransformState } from '../types.js' */
 /** @import { Node } from './types.js' */
@@ -31,14 +32,29 @@ function build_locations(nodes) {
 
 /**
  * @param {ComponentClientTransformState} state
- * @param {Namespace} namespace
+ * @param {string} name
  * @param {number} [flags]
  */
-export function transform_template(state, namespace, flags = 0) {
+export function transform_template(state, name, flags = 0) {
+	const namespace = state.metadata.namespace;
 	const tree = state.options.fragments === 'tree';
 
 	const expression = tree ? state.template.as_tree() : state.template.as_html();
 
+	const key =
+		tree || dev
+			? null
+			: get_template_key(
+					/** @type {TemplateLiteral} */ (expression),
+					state.metadata.namespace,
+					flags
+				);
+
+	if (key !== null) {
+		const existing = state.templates.get(key);
+		if (existing !== undefined) return existing;
+	}
+
 	if (tree) {
 		if (namespace === 'svg') flags |= TEMPLATE_USE_SVG;
 		if (namespace === 'mathml') flags |= TEMPLATE_USE_MATHML;
@@ -63,5 +79,26 @@ export function transform_template(state, namespace, flags = 0) {
 		);
 	}
 
-	return call;
+	const id = state.scope.root.unique(name);
+	state.hoisted.push(b.var(id, call));
+
+	if (key !== null) {
+		state.templates.set(key, id);
+	}
+
+	return id;
+}
+
+/**
+ * Returns a stable key for templates that are safe to deduplicate - plain
+ * `$.from_html`/`from_svg`/`from_mathml` factories with literal arguments - or `null`
+ * for anything else. Dev-mode templates are wrapped in `$.add_locations(...)`, which
+ * embeds per-call-site locations, so they never produce a key and are never shared.
+ * @param {TemplateLiteral} template
+ * @param {Namespace} namespace
+ * @param {number} flags
+ * @returns {string | null}
+ */
+function get_template_key(template, namespace, flags) {
+	return `${namespace} ${flags} ${template.quasis[0].value.raw}`;
 }
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/types.d.ts b/packages/svelte/src/compiler/phases/3-transform/client/types.d.ts
index 287bf24ac6..7a95a2d43c 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/types.d.ts
+++ b/packages/svelte/src/compiler/phases/3-transform/client/types.d.ts
@@ -40,6 +40,8 @@ export interface ComponentClientTransformState extends ClientTransformState {
 	readonly analysis: ComponentAnalysis;
 	readonly options: ValidatedCompileOptions;
 	readonly hoisted: Array<Statement | ModuleDeclaration>;
+	/** Deduplicates hoisted templates by content, mapping a template key to its hoisted identifier */
+	readonly templates: Map<string, Identifier>;
 	readonly events: Set<string>;
 	readonly store_to_invalidate?: string;
 
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/Fragment.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/Fragment.js
index ad0c487fb4..893b1db568 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/Fragment.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/Fragment.js
@@ -52,7 +52,6 @@ export function Fragment(node, context) {
 			(trimmed[0].type === 'IfBlock' &&
 				trimmed[0].elseif &&
 				/** @type {AST.IfBlock} */ (parent).metadata.flattened?.includes(trimmed[0])));
-	const template_name = context.state.scope.root.unique('root'); // TODO infer name from parent
 
 	/** @type {Statement[]} */
 	const body = [];
@@ -96,8 +95,7 @@ export function Fragment(node, context) {
 
 		let flags = state.template.needs_import_node ? TEMPLATE_USE_IMPORT_NODE : undefined;
 
-		const template = transform_template(state, namespace, flags);
-		state.hoisted.push(b.var(template_name, template));
+		const template_name = transform_template(state, 'root', flags);
 
 		state.init.unshift(b.var(id, b.call(template_name)));
 		close = b.stmt(b.call('$.append', b.id('$$anchor'), id));
@@ -147,8 +145,7 @@ export function Fragment(node, context) {
 				// special case — we can use `$.comment` instead of creating a unique template
 				state.init.unshift(b.var(id, b.call('$.comment')));
 			} else {
-				const template = transform_template(state, namespace, flags);
-				state.hoisted.push(b.var(template_name, template));
+				const template_name = transform_template(state, 'root', flags);
 
 				state.init.unshift(b.var(id, b.call(template_name)));
 			}
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
index 543f4aea17..8dcd3c7d6f 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
@@ -374,7 +374,6 @@ export function RegularElement(node, context) {
 		context.state.template.push_comment();
 
 		// Create a separate template for the rich content
-		const template_name = context.state.scope.root.unique(`${name}_content`);
 		const fragment_id = b.id(context.state.scope.generate('fragment'));
 		const anchor_id = b.id(context.state.scope.generate('anchor'));
 
@@ -398,9 +397,8 @@ export function RegularElement(node, context) {
 			}
 		);
 
-		// Transform the template to $.from_html(...) and hoist it
-		const template = transform_template(select_state, metadata.namespace, TEMPLATE_FRAGMENT);
-		context.state.hoisted.push(b.var(template_name, template));
+		// Transform the template to $.from_html(...) and hoist it (deduplicating identical templates)
+		const template_name = transform_template(select_state, `${name}_content`, TEMPLATE_FRAGMENT);
 
 		// Build the rich content function body
 		// The anchor is the child of the element (a hydration marker during hydration)
diff --git a/packages/svelte/tests/snapshot/samples/async-const/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-const/_expected/client/index.svelte.js
index 8bd7e97780..5c1d27ae54 100644
--- a/packages/svelte/tests/snapshot/samples/async-const/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-const/_expected/client/index.svelte.js
@@ -2,7 +2,7 @@ import 'svelte/internal/disclose-version';
 import 'svelte/internal/flags/async';
 import * as $ from 'svelte/internal/client';
 
-var root_1 = $.from_html(`<p> </p>`);
+var root = $.from_html(`<p> </p>`);
 
 export default function Async_const($$anchor) {
 	var fragment = $.comment();
@@ -18,7 +18,7 @@ export default function Async_const($$anchor) {
 				() => b = $.derived(() => $.get(a) + 1)
 			]);
 
-			var p = root_1();
+			var p = root();
 			var text = $.child(p, true);
 
 			$.reset(p);
diff --git a/packages/svelte/tests/snapshot/samples/dedupe-templates/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/dedupe-templates/_expected/client/index.svelte.js
new file mode 100644
index 0000000000..d0d474fa29
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/dedupe-templates/_expected/client/index.svelte.js
@@ -0,0 +1,44 @@
+import 'svelte/internal/disclose-version';
+import * as $ from 'svelte/internal/client';
+
+var root = $.from_html(`<p class="x">hello</p>`);
+var root_1 = $.from_html(`<!> <!>`, 1);
+
+export default function Dedupe_templates($$anchor, $$props) {
+	var fragment = root_1();
+	var node = $.first_child(fragment);
+
+	{
+		var consequent = ($$anchor) => {
+			var p = root();
+
+			$.append($$anchor, p);
+		};
+
+		var alternate = ($$anchor) => {
+			var p_1 = root();
+
+			$.append($$anchor, p_1);
+		};
+
+		$.if(node, ($$render) => {
+			if ($$props.a) $$render(consequent); else $$render(alternate, -1);
+		});
+	}
+
+	var node_1 = $.sibling(node, 2);
+
+	{
+		var consequent_1 = ($$anchor) => {
+			var p_2 = root();
+
+			$.append($$anchor, p_2);
+		};
+
+		$.if(node_1, ($$render) => {
+			if ($$props.b) $$render(consequent_1);
+		});
+	}
+
+	$.append($$anchor, fragment);
+}
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/dedupe-templates/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/dedupe-templates/_expected/server/index.svelte.js
new file mode 100644
index 0000000000..1f4a56779e
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/dedupe-templates/_expected/server/index.svelte.js
@@ -0,0 +1,24 @@
+import * as $ from 'svelte/internal/server';
+
+export default function Dedupe_templates($$renderer, $$props) {
+	let { a, b } = $$props;
+
+	if (a) {
+		$$renderer.push('<!--[0-->');
+		$$renderer.push(`<p class="x">hello</p>`);
+	} else {
+		$$renderer.push('<!--[-1-->');
+		$$renderer.push(`<p class="x">hello</p>`);
+	}
+
+	$$renderer.push(`<!--]--> `);
+
+	if (b) {
+		$$renderer.push('<!--[0-->');
+		$$renderer.push(`<p class="x">hello</p>`);
+	} else {
+		$$renderer.push('<!--[-1-->');
+	}
+
+	$$renderer.push(`<!--]-->`);
+}
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/dedupe-templates/index.svelte b/packages/svelte/tests/snapshot/samples/dedupe-templates/index.svelte
new file mode 100644
index 0000000000..c75b5481a5
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/dedupe-templates/index.svelte
@@ -0,0 +1,14 @@
+<script>
+	let { a, b } = $props();
+</script>
+
+<!-- identical static markup repeated across branches should share one hoisted template -->
+{#if a}
+	<p class="x">hello</p>
+{:else}
+	<p class="x">hello</p>
+{/if}
+
+{#if b}
+	<p class="x">hello</p>
+{/if}
diff --git a/packages/svelte/tests/snapshot/samples/delegated-locally-declared-shadowed/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/delegated-locally-declared-shadowed/_expected/client/index.svelte.js
index 43f2eadc09..d2f2f87f20 100644
--- a/packages/svelte/tests/snapshot/samples/delegated-locally-declared-shadowed/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/delegated-locally-declared-shadowed/_expected/client/index.svelte.js
@@ -2,14 +2,14 @@ import 'svelte/internal/disclose-version';
 import 'svelte/internal/flags/legacy';
 import * as $ from 'svelte/internal/client';
 
-var root_1 = $.from_html(`<button type="button">B</button>`);
+var root = $.from_html(`<button type="button">B</button>`);
 
 export default function Delegated_locally_declared_shadowed($$anchor) {
 	var fragment = $.comment();
 	var node = $.first_child(fragment);
 
 	$.each(node, 0, () => ({ length: 1 }), $.index, ($$anchor, $$item, index) => {
-		var button = root_1();
+		var button = root();
 
 		$.set_attribute(button, 'data-index', index);
 
diff --git a/packages/svelte/tests/snapshot/samples/each-index-non-null/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/each-index-non-null/_expected/client/index.svelte.js
index 804a7c26f1..049d47a96f 100644
--- a/packages/svelte/tests/snapshot/samples/each-index-non-null/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/each-index-non-null/_expected/client/index.svelte.js
@@ -2,14 +2,14 @@ import 'svelte/internal/disclose-version';
 import 'svelte/internal/flags/legacy';
 import * as $ from 'svelte/internal/client';
 
-var root_1 = $.from_html(`<p></p>`);
+var root = $.from_html(`<p></p>`);
 
 export default function Each_index_non_null($$anchor) {
 	var fragment = $.comment();
 	var node = $.first_child(fragment);
 
 	$.each(node, 0, () => Array(10), $.index, ($$anchor, $$item, i) => {
-		var p = root_1();
+		var p = root();
 
 		p.textContent = `index: ${i}`;
 		$.append($$anchor, p);
diff --git a/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js
index 8f8b115d70..c8354fe67e 100644
--- a/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js
@@ -4,63 +4,51 @@ import * as $ from 'svelte/internal/client';
 import Option from './Option.svelte';
 
 const opt = ($$anchor) => {
-	var option = root_1();
+	var option = root();
 
 	$.append($$anchor, option);
 };
 
 const option_snippet = ($$anchor) => {
-	var option_1 = root_2();
+	var option_1 = root_1();
 
 	$.append($$anchor, option_1);
 };
 
 const option_snippet2 = ($$anchor) => {
-	var option_2 = root_3();
+	var option_2 = root_2();
 
 	$.append($$anchor, option_2);
 };
 
 const conditional_option = ($$anchor) => {
-	var option_3 = root_4();
+	var option_3 = root_3();
 
 	$.append($$anchor, option_3);
 };
 
-var root_1 = $.from_html(`<option>Snippet</option>`);
-var root_2 = $.from_html(`<option>Rendered</option>`);
-var root_3 = $.from_html(`<option>Rendered in group</option>`);
-var root_4 = $.from_html(`<option>Conditional</option>`);
+var root = $.from_html(`<option>Snippet</option>`);
+var root_1 = $.from_html(`<option>Rendered</option>`);
+var root_2 = $.from_html(`<option>Rendered in group</option>`);
+var root_3 = $.from_html(`<option>Conditional</option>`);
 var option_content = $.from_html(`<span>Rich</span>`, 1);
-var root_5 = $.from_html(`<option> </option>`);
-var root_6 = $.from_html(`<option>Visible</option>`);
-var root_7 = $.from_html(`<option>Keyed</option>`);
+var root_4 = $.from_html(`<option> </option>`);
+var root_5 = $.from_html(`<option>Visible</option>`);
+var root_6 = $.from_html(`<option>Keyed</option>`);
 var select_content = $.from_html(`<!>`, 1);
-var root_8 = $.from_html(`<option> </option>`);
 var option_content_1 = $.from_html(`<strong>Bold</strong>`, 1);
-var root_9 = $.from_html(`<option> </option>`);
 var option_content_2 = $.from_html(`<em>Italic</em> text`, 1);
 var option_content_3 = $.from_html(`<span> </span>`, 1);
-var root_10 = $.from_html(`<option><!></option>`);
-var root_12 = $.from_html(`<option> </option>`);
-var root_13 = $.from_html(`<option>Boundary</option>`);
+var root_7 = $.from_html(`<option><!></option>`);
+var root_8 = $.from_html(`<option>Boundary</option>`);
 var option_content_4 = $.from_html(`<span>Rich in boundary</span>`, 1);
-var root_14 = $.from_html(`<option><!></option>`);
-var select_content_1 = $.from_html(`<!>`, 1);
-var select_content_2 = $.from_html(`<!>`, 1);
-var select_content_3 = $.from_html(`<!>`, 1);
-var optgroup_content = $.from_html(`<!>`, 1);
-var optgroup_content_1 = $.from_html(`<!>`, 1);
-var option_content_5 = $.from_html(`<!>`, 1);
-var select_content_4 = $.from_html(`<!>`, 1);
-var select_content_5 = $.from_html(`<!>`, 1);
-var root = $.from_html(`<select><option><!></option></select> <select></select> <select><!></select> <select><!></select>  <select><!></select> <select></select> <select><optgroup label="Group"><option><!></option></optgroup></select> <select><optgroup label="Group"></optgroup></select> <select><option><!></option></select> <select></select> <select><!></select> <select><!></select> <select><!></select> <select><!></select>  <select><!></select> <select><!></select> <select><optgroup label="Group"><!></optgroup></select>  <select><optgroup label="Group"><!></optgroup></select> <select><option><!></option></select> <select><!></select>  <select><!></select>`, 1);
+var root_9 = $.from_html(`<select><option><!></option></select> <select></select> <select><!></select> <select><!></select>  <select><!></select> <select></select> <select><optgroup label="Group"><option><!></option></optgroup></select> <select><optgroup label="Group"></optgroup></select> <select><option><!></option></select> <select></select> <select><!></select> <select><!></select> <select><!></select> <select><!></select>  <select><!></select> <select><!></select> <select><optgroup label="Group"><!></optgroup></select>  <select><optgroup label="Group"><!></optgroup></select> <select><option><!></option></select> <select><!></select>  <select><!></select>`, 1);
 
 export default function Select_with_rich_content($$anchor) {
 	let items = [1, 2, 3];
 	let show = true;
 	let html = '<option>From HTML</option>';
-	var fragment = root();
+	var fragment = root_9();
 	var select = $.first_child(fragment);
 	var option_4 = $.child(select);
 
@@ -76,7 +64,7 @@ export default function Select_with_rich_content($$anchor) {
 	var select_1 = $.sibling(select, 2);
 
 	$.each(select_1, 5, () => items, $.index, ($$anchor, item) => {
-		var option_5 = root_5();
+		var option_5 = root_4();
 		var text = $.child(option_5, true);
 
 		$.reset(option_5);
@@ -101,7 +89,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	{
 		var consequent = ($$anchor) => {
-			var option_6 = root_6();
+			var option_6 = root_5();
 
 			$.append($$anchor, option_6);
 		};
@@ -117,7 +105,7 @@ export default function Select_with_rich_content($$anchor) {
 	var node_1 = $.child(select_3);
 
 	$.key(node_1, () => items, ($$anchor) => {
-		var option_7 = root_7();
+		var option_7 = root_6();
 
 		$.append($$anchor, option_7);
 	});
@@ -139,7 +127,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.each(select_5, 5, () => items, $.index, ($$anchor, item) => {
 		const x = $.derived_safe_equal(() => $.get(item) * 2);
-		var option_8 = root_8();
+		var option_8 = root_4();
 		var text_1 = $.child(option_8, true);
 
 		$.reset(option_8);
@@ -177,7 +165,7 @@ export default function Select_with_rich_content($$anchor) {
 	var optgroup_1 = $.child(select_7);
 
 	$.each(optgroup_1, 5, () => items, $.index, ($$anchor, item) => {
-		var option_10 = root_9();
+		var option_10 = root_4();
 		var text_2 = $.child(option_10, true);
 
 		$.reset(option_10);
@@ -215,7 +203,7 @@ export default function Select_with_rich_content($$anchor) {
 	var select_9 = $.sibling(select_8, 2);
 
 	$.each(select_9, 5, () => items, $.index, ($$anchor, item) => {
-		var option_12 = root_10();
+		var option_12 = root_7();
 
 		$.customizable_select(option_12, () => {
 			var anchor_4 = $.child(option_12);
@@ -242,7 +230,7 @@ export default function Select_with_rich_content($$anchor) {
 			var node_4 = $.first_child(fragment_6);
 
 			$.each(node_4, 1, () => items, $.index, ($$anchor, item) => {
-				var option_13 = root_12();
+				var option_13 = root_4();
 				var text_4 = $.child(option_13, true);
 
 				$.reset(option_13);
@@ -274,7 +262,7 @@ export default function Select_with_rich_content($$anchor) {
 	var node_5 = $.child(select_11);
 
 	$.boundary(node_5, {}, ($$anchor) => {
-		var option_14 = root_13();
+		var option_14 = root_8();
 
 		$.append($$anchor, option_14);
 	});
@@ -285,7 +273,7 @@ export default function Select_with_rich_content($$anchor) {
 	var node_6 = $.child(select_12);
 
 	$.boundary(node_6, {}, ($$anchor) => {
-		var option_15 = root_14();
+		var option_15 = root_7();
 
 		$.customizable_select(option_15, () => {
 			var anchor_5 = $.child(option_15);
@@ -303,7 +291,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.customizable_select(select_13, () => {
 		var anchor_6 = $.child(select_13);
-		var fragment_8 = select_content_1();
+		var fragment_8 = select_content();
 		var node_7 = $.first_child(fragment_8);
 
 		Option(node_7, {});
@@ -314,7 +302,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.customizable_select(select_14, () => {
 		var anchor_7 = $.child(select_14);
-		var fragment_9 = select_content_2();
+		var fragment_9 = select_content();
 		var node_8 = $.first_child(fragment_9);
 
 		option_snippet(node_8);
@@ -325,7 +313,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.customizable_select(select_15, () => {
 		var anchor_8 = $.child(select_15);
-		var fragment_10 = select_content_3();
+		var fragment_10 = select_content();
 		var node_9 = $.first_child(fragment_10);
 
 		$.html(node_9, () => html);
@@ -337,7 +325,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.customizable_select(optgroup_2, () => {
 		var anchor_9 = $.child(optgroup_2);
-		var fragment_11 = optgroup_content();
+		var fragment_11 = select_content();
 		var node_10 = $.first_child(fragment_11);
 
 		Option(node_10, {});
@@ -351,7 +339,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.customizable_select(optgroup_3, () => {
 		var anchor_10 = $.child(optgroup_3);
-		var fragment_12 = optgroup_content_1();
+		var fragment_12 = select_content();
 		var node_11 = $.first_child(fragment_12);
 
 		option_snippet2(node_11);
@@ -365,7 +353,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.customizable_select(option_16, () => {
 		var anchor_11 = $.child(option_16);
-		var fragment_13 = option_content_5();
+		var fragment_13 = select_content();
 		var node_12 = $.first_child(fragment_13);
 
 		$.html(node_12, () => '<strong>Bold HTML</strong>');
@@ -378,7 +366,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.customizable_select(select_19, () => {
 		var anchor_12 = $.child(select_19);
-		var fragment_14 = select_content_4();
+		var fragment_14 = select_content();
 		var node_13 = $.first_child(fragment_14);
 
 		$.each(node_13, 1, () => items, $.index, ($$anchor, item) => {
@@ -392,7 +380,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.customizable_select(select_20, () => {
 		var anchor_13 = $.child(select_20);
-		var fragment_16 = select_content_5();
+		var fragment_16 = select_content();
 		var node_14 = $.first_child(fragment_16);
 
 		{

From 6a955758a67a3c9c80f58c45961c0db2a52d463f Mon Sep 17 00:00:00 2001
From: 7nik <kifiranet@gmail.com>
Date: Fri, 29 May 2026 23:22:55 +0300
Subject: [PATCH 059/222] docs: mention since version of delcaration tags
 (#18322)

---
 documentation/docs/03-template-syntax/11-declaration-tags.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/documentation/docs/03-template-syntax/11-declaration-tags.md b/documentation/docs/03-template-syntax/11-declaration-tags.md
index 34b7164775..e0edaf6a38 100644
--- a/documentation/docs/03-template-syntax/11-declaration-tags.md
+++ b/documentation/docs/03-template-syntax/11-declaration-tags.md
@@ -20,6 +20,8 @@ Declaration tags define local variables inside markup with `const` or `let`:
 ```
 <!-- codeblock:end -->
 
+> [!NOTE] Declaration tags are available since Svelte 5.56.
+
 > [!NOTE] The [`{@const ...}`](@const) syntax is considered legacy — use declaration tags instead.
 
 When values should be reactive, you can use `$state` and `$derived`:

From 6d26dce265de128d65a99e1735e576651d9c1a75 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 29 May 2026 17:05:12 -0400
Subject: [PATCH 060/222] allow class/function expressions in tags (#18324)

We shouldn't error on encountering `class` and `function`, because they
are treated as expressions rather than declarations
---
 .../src/compiler/phases/1-parse/state/tag.js      |  3 +--
 .../declaration-tag-invalid-function/errors.json  | 15 +--------------
 2 files changed, 2 insertions(+), 16 deletions(-)

diff --git a/packages/svelte/src/compiler/phases/1-parse/state/tag.js b/packages/svelte/src/compiler/phases/1-parse/state/tag.js
index 45d0081707..3c8eba4b26 100644
--- a/packages/svelte/src/compiler/phases/1-parse/state/tag.js
+++ b/packages/svelte/src/compiler/phases/1-parse/state/tag.js
@@ -14,8 +14,7 @@ const regex_whitespace_with_closing_curly_brace = /\s*}/y;
 const regex_supported_declaration = /(?:let|const)\b/y;
 // All except `type` are reserved keywords and cannot be used as variable names.
 // For type we check if it's not something like `type .x` / `type ()` / `type % 2` / ...
-const regex_unsupported_declaration =
-	/(?:(?:var|function|class|interface|enum)\b)|(?:type\s+[^?.(`<[&|%^}])/y;
+const regex_unsupported_declaration = /(?:(?:var|interface|enum)\b)|(?:type\s+[^?.(`<[&|%^}])/y;
 
 const pointy_bois = { '<': '>' };
 
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-invalid-function/errors.json b/packages/svelte/tests/validator/samples/declaration-tag-invalid-function/errors.json
index bf0266225f..fe51488c70 100644
--- a/packages/svelte/tests/validator/samples/declaration-tag-invalid-function/errors.json
+++ b/packages/svelte/tests/validator/samples/declaration-tag-invalid-function/errors.json
@@ -1,14 +1 @@
-[
-	{
-		"code": "declaration_tag_invalid_type",
-		"message": "Declaration tags must be `let` or `const` declarations",
-		"start": {
-			"line": 2,
-			"column": 2
-		},
-		"end": {
-			"line": 2,
-			"column": 10
-		}
-	}
-]
+[]

From 70afafe18e48a9973c5f711d62d87d088234655e Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Fri, 29 May 2026 17:55:34 -0400
Subject: [PATCH 061/222] Version Packages (#18315)

This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.


# Releases
## svelte@5.56.0

### Minor Changes

- feat: allow declarations in the template
([#18282](https://github.com/sveltejs/svelte/pull/18282))

### Patch Changes

- perf: use `createElement` instead of `createElementNS` for HTML
elements ([#18262](https://github.com/sveltejs/svelte/pull/18262))

- perf: store `current_sources` as a `Set` for O(1) membership checks
([#18278](https://github.com/sveltejs/svelte/pull/18278))

- perf: deduplicate identical hoisted templates within a component
([#18320](https://github.com/sveltejs/svelte/pull/18320))

- perf: hoist `rest_props` exclude list as a module-scope `Set`
([#18252](https://github.com/sveltejs/svelte/pull/18252))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/create-element-fast-path.md |  5 -----
 .changeset/current-sources-set.md      |  5 -----
 .changeset/dedupe-hoisted-templates.md |  5 -----
 .changeset/four-loops-agree.md         |  5 -----
 .changeset/hoist-rest-excludes.md      |  5 -----
 packages/svelte/CHANGELOG.md           | 16 ++++++++++++++++
 packages/svelte/package.json           |  2 +-
 packages/svelte/src/version.js         |  2 +-
 8 files changed, 18 insertions(+), 27 deletions(-)
 delete mode 100644 .changeset/create-element-fast-path.md
 delete mode 100644 .changeset/current-sources-set.md
 delete mode 100644 .changeset/dedupe-hoisted-templates.md
 delete mode 100644 .changeset/four-loops-agree.md
 delete mode 100644 .changeset/hoist-rest-excludes.md

diff --git a/.changeset/create-element-fast-path.md b/.changeset/create-element-fast-path.md
deleted file mode 100644
index 8b88a14163..0000000000
--- a/.changeset/create-element-fast-path.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-perf: use `createElement` instead of `createElementNS` for HTML elements
diff --git a/.changeset/current-sources-set.md b/.changeset/current-sources-set.md
deleted file mode 100644
index e1a4dc43b2..0000000000
--- a/.changeset/current-sources-set.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-perf: store `current_sources` as a `Set` for O(1) membership checks
diff --git a/.changeset/dedupe-hoisted-templates.md b/.changeset/dedupe-hoisted-templates.md
deleted file mode 100644
index a91882f525..0000000000
--- a/.changeset/dedupe-hoisted-templates.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-perf: deduplicate identical hoisted templates within a component
diff --git a/.changeset/four-loops-agree.md b/.changeset/four-loops-agree.md
deleted file mode 100644
index 46d30e8464..0000000000
--- a/.changeset/four-loops-agree.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': minor
----
-
-feat: allow declarations in the template
diff --git a/.changeset/hoist-rest-excludes.md b/.changeset/hoist-rest-excludes.md
deleted file mode 100644
index 52efb06092..0000000000
--- a/.changeset/hoist-rest-excludes.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-perf: hoist `rest_props` exclude list as a module-scope `Set`
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index ef40c5d159..57725580e7 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,21 @@
 # svelte
 
+## 5.56.0
+
+### Minor Changes
+
+- feat: allow declarations in the template ([#18282](https://github.com/sveltejs/svelte/pull/18282))
+
+### Patch Changes
+
+- perf: use `createElement` instead of `createElementNS` for HTML elements ([#18262](https://github.com/sveltejs/svelte/pull/18262))
+
+- perf: store `current_sources` as a `Set` for O(1) membership checks ([#18278](https://github.com/sveltejs/svelte/pull/18278))
+
+- perf: deduplicate identical hoisted templates within a component ([#18320](https://github.com/sveltejs/svelte/pull/18320))
+
+- perf: hoist `rest_props` exclude list as a module-scope `Set` ([#18252](https://github.com/sveltejs/svelte/pull/18252))
+
 ## 5.55.10
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 713c7c04c0..6e51dd9a93 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.55.10",
+  "version": "5.56.0",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 638534d369..1b080d134a 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.55.10';
+export const VERSION = '5.56.0';
 export const PUBLIC_VERSION = '5';

From e027d8bf224256714778b4fff41a926177a457f9 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 29 May 2026 17:55:55 -0400
Subject: [PATCH 062/222] chore: annotate `each_array` return value (#18325)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

tiny self-mergeable change extracted from #18035 — just turns
`each_array` from a `Derived<any[]>` to a `Derived<V[]>`
---
 packages/svelte/src/internal/client/dom/blocks/each.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/svelte/src/internal/client/dom/blocks/each.js b/packages/svelte/src/internal/client/dom/blocks/each.js
index 5f8adee1b5..2df1d6ffa1 100644
--- a/packages/svelte/src/internal/client/dom/blocks/each.js
+++ b/packages/svelte/src/internal/client/dom/blocks/each.js
@@ -203,7 +203,9 @@ export function each(node, flags, get_collection, get_key, render_fn, fallback_f
 	var each_array = derived_safe_equal(() => {
 		var collection = get_collection();
 
-		return is_array(collection) ? collection : collection == null ? [] : array_from(collection);
+		return /** @type {V[]} */ (
+			is_array(collection) ? collection : collection == null ? [] : array_from(collection)
+		);
 	});
 
 	if (DEV) {

From 05a3bce6bbfb10f19376ae2fcd5a80e92c7384c5 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Sat, 30 May 2026 08:03:58 -0400
Subject: [PATCH 063/222] chore: minor tidy-ups (#18326)

some more stuff extracted from #18035
---
 .../client/dom/elements/bindings/input.js     |  1 -
 .../src/internal/client/reactivity/async.js   | 33 +++++++++++++------
 .../src/internal/client/reactivity/effects.js |  6 ++--
 3 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/packages/svelte/src/internal/client/dom/elements/bindings/input.js b/packages/svelte/src/internal/client/dom/elements/bindings/input.js
index 55e61c3774..dadcac369c 100644
--- a/packages/svelte/src/internal/client/dom/elements/bindings/input.js
+++ b/packages/svelte/src/internal/client/dom/elements/bindings/input.js
@@ -7,7 +7,6 @@ import { is } from '../../../proxy.js';
 import { queue_micro_task } from '../../task.js';
 import { hydrating } from '../../hydration.js';
 import { tick, untrack } from '../../../runtime.js';
-import { is_runes } from '../../../context.js';
 import { current_batch, previous_batch } from '../../../reactivity/batch.js';
 import { async_mode_flag } from '../../../../flags/index.js';
 
diff --git a/packages/svelte/src/internal/client/reactivity/async.js b/packages/svelte/src/internal/client/reactivity/async.js
index 89115108d5..32d33d6f7a 100644
--- a/packages/svelte/src/internal/client/reactivity/async.js
+++ b/packages/svelte/src/internal/client/reactivity/async.js
@@ -1,4 +1,4 @@
-/** @import { Blocker, Effect, Value } from '#client' */
+/** @import { Blocker, Effect, Source, Value } from '#client' */
 import { DESTROYED, STALE_REACTION } from '#client/constants';
 import { DEV } from 'esm-env';
 import {
@@ -38,8 +38,22 @@ export function flatten(blockers, sync, async, fn) {
 	// Filter out already-settled blockers - no need to wait for them
 	var pending = blockers.filter((b) => !b.settled);
 
+	var deriveds = sync.map(d);
+
+	if (DEV) {
+		deriveds.forEach((d, i) => {
+			// TODO this is kinda useful for debugging but a lousy implementation —
+			// maybe the compiler could pass through the template string
+			d.label = sync[i]
+				.toString()
+				.replace('() => ', '')
+				.replaceAll('$.eager(() => ', '$state.eager(')
+				.replace(/\$\.get\((.+?)\)/g, (_, id) => id);
+		});
+	}
+
 	if (async.length === 0 && pending.length === 0) {
-		fn(sync.map(d));
+		fn(deriveds);
 		return;
 	}
 
@@ -53,8 +67,10 @@ export function flatten(blockers, sync, async, fn) {
 				? Promise.all(pending.map((b) => b.promise))
 				: null;
 
-	/** @param {Value[]} values */
-	function finish(values) {
+	/**
+	 * @param {Source[]} async
+	 */
+	function finish(async) {
 		if ((parent.f & DESTROYED) !== 0) {
 			return;
 		}
@@ -62,7 +78,7 @@ export function flatten(blockers, sync, async, fn) {
 		restore();
 
 		try {
-			fn(values);
+			fn([...deriveds, ...async]);
 		} catch (error) {
 			invoke_error_boundary(error, parent);
 		}
@@ -74,17 +90,14 @@ export function flatten(blockers, sync, async, fn) {
 
 	// Fast path: blockers but no async expressions
 	if (async.length === 0) {
-		/** @type {Promise<any>} */ (blocker_promise)
-			.then(() => finish(sync.map(d)))
-			.finally(decrement_pending);
-
+		/** @type {Promise<any>} */ (blocker_promise).then(() => finish([])).finally(decrement_pending);
 		return;
 	}
 
 	// Full path: has async expressions
 	function run() {
 		Promise.all(async.map((expression) => async_derived(expression)))
-			.then((result) => finish([...sync.map(d), ...result]))
+			.then(finish)
 			.catch((error) => invoke_error_boundary(error, parent))
 			.finally(decrement_pending);
 	}
diff --git a/packages/svelte/src/internal/client/reactivity/effects.js b/packages/svelte/src/internal/client/reactivity/effects.js
index 1bbda86fa7..c5d195dfae 100644
--- a/packages/svelte/src/internal/client/reactivity/effects.js
+++ b/packages/svelte/src/internal/client/reactivity/effects.js
@@ -387,7 +387,9 @@ export function render_effect(fn, flags = 0) {
  */
 export function template_effect(fn, sync = [], async = [], blockers = []) {
 	flatten(blockers, sync, async, (values) => {
-		create_effect(RENDER_EFFECT, () => fn(...values.map(get)));
+		create_effect(RENDER_EFFECT, () => {
+			fn(...values.map(get));
+		});
 	});
 }
 
@@ -518,7 +520,7 @@ export function destroy_effect(effect, remove_dom = true) {
 		removed = true;
 	}
 
-	set_signal_status(effect, DESTROYING);
+	effect.f |= DESTROYING;
 	destroy_effect_children(effect, remove_dom && !removed);
 	remove_reactions(effect, 0);
 

From 11985c020fe1f7f7755494929c5d59f44a45e990 Mon Sep 17 00:00:00 2001
From: ottomated <31470743+ottomated@users.noreply.github.com>
Date: Sun, 31 May 2026 08:41:49 -0700
Subject: [PATCH 064/222] docs: desloppify browser support page (#18333)

The text in https://svelte.dev/docs/svelte/browser-support is quite
redundant and has a lot of AI smell. I did my best to make it more
concise and remove some slop comments in the generation script.

Requires a companion PR in svelte.dev:
https://github.com/sveltejs/svelte.dev/pull/2013

<img width="620" height="809" alt="image"
src="https://github.com/user-attachments/assets/7be9d5ff-1623-4897-a2d4-9a601b20f54d"
/>

### Before submitting the PR, please make sure you do the following

- [ ] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [ ] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).

### Tests and linting

- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .prettierignore                               |   1 +
 .../.generated/browser-support-features.md    |   8 +-
 .../07-misc/.generated/browser-support.md     |  20 +-
 .../docs/07-misc/05-browser-support.md        |  23 +--
 .../scripts/generate-browser-support.ts       | 175 +++++++++---------
 5 files changed, 109 insertions(+), 118 deletions(-)

diff --git a/.prettierignore b/.prettierignore
index 92d9bc797b..28f447f359 100644
--- a/.prettierignore
+++ b/.prettierignore
@@ -8,6 +8,7 @@ packages/**/config/*.js
 # packages/svelte
 packages/svelte/messages/**/*.md
 packages/svelte/scripts/_bundle.js
+packages/svelte/scripts/_baseline/*.ts
 packages/svelte/src/compiler/errors.js
 packages/svelte/src/compiler/warnings.js
 packages/svelte/src/internal/client/errors.js
diff --git a/documentation/docs/07-misc/.generated/browser-support-features.md b/documentation/docs/07-misc/.generated/browser-support-features.md
index 1e1a00d4d3..1ed6da9e61 100644
--- a/documentation/docs/07-misc/.generated/browser-support-features.md
+++ b/documentation/docs/07-misc/.generated/browser-support-features.md
@@ -1,7 +1,7 @@
 <!-- generated in ../../../../../packages/svelte/scripts/generate-browser-support.ts. do not edit -->
 
 | Feature | Chrome/Edge | Firefox | Safari |
-| --- | ---: | ---: | ---: |
-| `$state.snapshot` | 98 | 94 | 15.4 |
-| `bind:devicePixelContentBoxSize` | <span style="color: var(--sk-fg-4)">—</span> | 93 | not supported |
-| `flip` from `svelte/animate` | <span style="color: var(--sk-fg-4)">—</span> | 126 | <span style="color: var(--sk-fg-4)">—</span> |
\ No newline at end of file
+| - | - | - | - |
+| [`$state.snapshot`](/docs/svelte/$state#$state.snapshot) | 98 | 94 | 15.4 |
+| [`bind:devicePixelContentBoxSize`](/docs/svelte/bind#Dimensions) | <span style="color: var(--sk-fg-4)">—</span> | 93 | not supported |
+| [`flip` from `svelte/animate`](/docs/svelte/svelte-animate#flip) | <span style="color: var(--sk-fg-4)">—</span> | 126 | <span style="color: var(--sk-fg-4)">—</span> |
diff --git a/documentation/docs/07-misc/.generated/browser-support.md b/documentation/docs/07-misc/.generated/browser-support.md
index 8c58588960..1e8b962856 100644
--- a/documentation/docs/07-misc/.generated/browser-support.md
+++ b/documentation/docs/07-misc/.generated/browser-support.md
@@ -1,13 +1,15 @@
 <!-- generated in ../../../../../packages/svelte/scripts/generate-browser-support.ts. do not edit -->
 
-| Browser          | Minimum version |
-| ---------------- | --------------- |
-| Chrome/Edge      | 87              |
-| Firefox          | 83              |
-| Safari           | 14              |
-| Opera            | 73              |
-| Opera (Android)  | 62              |
-| Samsung Internet | 14.0            |
-| Android WebView  | 87              |
+| Browser | Minimum version |
+| - | - |
+| Chrome/Edge | 87 |
+| Firefox | 83 |
+| Safari | 14 |
+| Opera | 73 |
+| Opera (Android) | 62 |
+| Samsung Internet | 14.0 |
+| Android WebView | 87 |
+| Internet Explorer | not supported |
+
 
 > [!NOTE] This equates to a <a href="https://web-platform-dx.github.io/baseline/">Baseline</a> target of 2020.
\ No newline at end of file
diff --git a/documentation/docs/07-misc/05-browser-support.md b/documentation/docs/07-misc/05-browser-support.md
index 1a8830bdb9..735f3126de 100644
--- a/documentation/docs/07-misc/05-browser-support.md
+++ b/documentation/docs/07-misc/05-browser-support.md
@@ -2,29 +2,14 @@
 title: Browser support
 ---
 
-The table below shows the minimum browser versions Svelte's runtime and compiled output are expected to work in.
+The table below shows the minimum browser versions Svelte is expected to work in, derived from the browser APIs used by Svelte's internal code.
 
 @include .generated/browser-support.md
 
-These numbers describe what Svelte's output _requires_ in order to run — they're derived from the APIs the code uses, not from a list of browsers the team commits to testing.
+This table only covers Svelte itself. It does not include [SvelteKit](/docs/kit), other Svelte libraries, or your own code.
 
-## What is covered
+## Exceptions
 
-- **Svelte's runtime.** Everything you import from `svelte` or its subpackages, in the form your bundler ships to the browser.
-- **Compiler output.** The JavaScript the Svelte compiler emits from your `.svelte` files, including the DOM operations, bindings and transitions used in your components.
-
-## What is not covered
-
-- **Your own code** inside `<script>` blocks or `.svelte.js` files. If you use newer browser APIs the table will not reflect them — configure your own [browserslist](https://github.com/browserslist/browserslist) and polyfills accordingly.
-- **SvelteKit**, adapters and build tooling. See the [SvelteKit docs](https://svelte.dev/docs/kit) for the browser support story there.
-- **Internet Explorer 11.** Svelte's runtime relies on `Proxy`, which cannot be polyfilled. IE11 is not supported and there is no path to making it work.
-
-## Per-feature browser requirements
-
-Some Svelte features rely on browser APIs that exceed the floor above. The runtime still loads on older browsers — modern bundlers tree-shake the affected code when the feature is unused — but if you use one of these features, you need the higher minimum version listed here.
+A few Svelte features require a higher minimum browser version. You'll only need to take the following table into consideration if you use these specific features.
 
 @include .generated/browser-support-features.md
-
-## How this page stays accurate
-
-The minimum versions can only move forward in a minor or major release, and any change is recorded in the [changelog](https://github.com/sveltejs/svelte/blob/main/packages/svelte/CHANGELOG.md). Every Svelte feature — bindings, runes, directives, and module exports — is checked against the [web-features](https://www.npmjs.com/package/web-features) Baseline dataset on every pull request, and the build fails if a change requires newer browsers than the page reflects.
diff --git a/packages/svelte/scripts/generate-browser-support.ts b/packages/svelte/scripts/generate-browser-support.ts
index b447ba3bdc..0a35a29413 100644
--- a/packages/svelte/scripts/generate-browser-support.ts
+++ b/packages/svelte/scripts/generate-browser-support.ts
@@ -1,3 +1,4 @@
+/* eslint-disable no-console */
 // Regenerates `documentation/docs/07-misc/05-browser-support.md`.
 //
 // Pipeline:
@@ -46,10 +47,17 @@ type BrowserVersions = Record<string, string | null>;
 type RuntimeFloor = number | 'newly';
 type ConditionalRow = {
 	name: string;
+	doc_link: string | null;
 	versions: BrowserVersions;
 	baseline_year: RuntimeFloor;
 };
 
+const doc_links: Record<string, string | null> = {
+	'`$state.snapshot`': '/docs/svelte/$state#$state.snapshot',
+	'`bind:devicePixelContentBoxSize`': '/docs/svelte/bind#Dimensions',
+	'`flip` from `svelte/animate`': '/docs/svelte/svelte-animate#flip'
+};
+
 // Supplemental detection rules for APIs `web-features` doesn't track
 // yet. Each rule is checked with full TS type-aware precision — the
 // only reason it lives here instead of being auto-derived is that no
@@ -125,13 +133,7 @@ const SAFE_TO_IGNORE = new Set(['devicepixelratio', 'trusted-types']);
 /**
  * Suppressions for features that DO live in the runtime but are reached
  * only via a specific code path documented in the per-feature table on
- * the docs page. The aggregate scan hides them so the headline floor
- * reflects "load Svelte and use the basic runtime", not "use every
- * conditional feature".
- *
- * Each entry MUST appear in the conditional-features table. The
- * staleness check below also verifies the entry is still present in the
- * runtime — if the detector doesn't flag it, the entry can be removed.
+ * the docs page.
  */
 const BEHAVIORAL_IGNORE = new Set([
 	'structured-clone',
@@ -203,7 +205,6 @@ async function enumerate_subpackage_exports(): Promise<Record<string, string[]>>
 			if (names.length > 0) result[module_id] = names;
 		} catch (err) {
 			const message = err instanceof Error ? err.message : String(err);
-			// eslint-disable-next-line no-console
 			console.warn(`  (could not enumerate ${module_id}: ${message.split('\n')[0]})`);
 		}
 	}
@@ -437,10 +438,8 @@ function find_minimum_target(
 	// detected feature happens to lack a Baseline year.
 	const final_year = Math.max(year, 2015);
 
-	// eslint-disable-next-line no-console
 	console.log(`  → ${final_year} (features that drove the floor:)`);
 	for (const id of [...drivers].sort()) {
-		// eslint-disable-next-line no-console
 		console.log(`    - ${id}`);
 	}
 
@@ -455,7 +454,6 @@ function find_minimum_target(
  *
  * `SAFE_TO_IGNORE` entries are exempt: they're safe to carry regardless
  * of whether the runtime currently uses the API.
- *
  */
 function validate_ignore_features(runtime_files: string[]): void {
 	if (BEHAVIORAL_IGNORE.size === 0) return;
@@ -528,14 +526,12 @@ function enumerate_features(subpackage_exports: Record<string, string[]>): Featu
  * Produce the `.svelte` source for a single binding fixture. Returns
  * `null` for bindings the compiler treats as elements rather than
  * properties (none currently, but defensive).
- *
  */
 function binding_fixture(name: string, props: BindingProperty): string {
 	// Map declared `valid_elements` to a concrete element + minimal attrs
 	// so the compiler accepts the binding.
 	const tag = (props.valid_elements ?? ['div'])[0];
 
-	// Pick a sensible initial value and attribute set per binding.
 	const reactive = `let v = $state();`;
 
 	if (tag === 'svelte:window') {
@@ -545,7 +541,7 @@ function binding_fixture(name: string, props: BindingProperty): string {
 		return `<script>${reactive}</script><svelte:document bind:${name}={v} />`;
 	}
 	if (tag === 'input') {
-		// `bind:checked` requires type="checkbox"|"radio"; `bind:group` too.
+		// `bind:checked` and `bind:group` require type="checkbox" | "radio"
 		const type =
 			name === 'checked' || name === 'indeterminate'
 				? ' type="checkbox"'
@@ -567,7 +563,6 @@ function binding_fixture(name: string, props: BindingProperty): string {
  * Compile a `.svelte` fixture to JS (no-op for `.js` fixtures), then
  * bundle the result through the shared `bundle` helper. Fixtures are tiny
  * so circular-dep warnings from the Svelte runtime are silenced.
- *
  */
 async function bundle_fixture(feature: Feature): Promise<string> {
 	const entry_code =
@@ -612,6 +607,8 @@ async function find_all_conditional_features(
 	const features = enumerate_features(subpackage_exports);
 	const rows: ConditionalRow[] = [];
 
+	const missing_doc_links: string[] = [];
+
 	for (let i = 0; i < features.length; i++) {
 		const feature = features[i];
 		process.stdout.write(`\r  ${i + 1}/${features.length}  ${feature.name}`.padEnd(80));
@@ -645,25 +642,35 @@ async function find_all_conditional_features(
 			}
 		}
 
+		let doc_link = doc_links[feature.name];
+		if (doc_link === undefined) {
+			doc_link = null;
+			missing_doc_links.push(feature.name);
+		}
+
 		rows.push({
 			name: feature.name,
+			doc_link,
 			versions,
 			baseline_year: final_year
 		});
 	}
 	process.stdout.write('\n');
 
+	if (missing_doc_links.length) {
+		throw new Error(`Missing documentation url for some features.
+Add them to the \`doc_links\` map in \`scripts/generate-browser-support.ts\`, or add an explicit \`null\` if they don't have a documentation url.
+${missing_doc_links.map((name) => `  - "${name}"`).join('\n')}`);
+	}
+
 	return rows;
 }
 
-/**
- * Render the per-feature browser-requirements table from the auto-detected
- * rows. Sorted by Safari floor descending, then alphabetically.
- */
-function render_conditional_table(rows: ConditionalRow[], runtime_floor: RuntimeFloor): string {
-	if (rows.length === 0) {
+function render_conditional_table(features: ConditionalRow[], runtime_floor: RuntimeFloor): string {
+	if (features.length === 0) {
 		return '_No features currently require browser versions newer than the runtime floor._';
 	}
+	features.sort((a, b) => a.name.localeCompare(b.name));
 
 	const browsers = [
 		['chrome', 'Chrome/Edge'],
@@ -671,32 +678,25 @@ function render_conditional_table(rows: ConditionalRow[], runtime_floor: Runtime
 		['safari', 'Safari']
 	] as const;
 
-	const runtime_versions = browser_versions_for(runtime_floor);
-
-	const sorted = [...rows].sort((a, b) => {
-		const sa = Number(a.versions.safari ?? '0');
-		const sb = Number(b.versions.safari ?? '0');
-		if (sb !== sa) return sb - sa;
-		return a.name.localeCompare(b.name);
-	});
-
-	const header = '| Feature | ' + browsers.map(([, label]) => `${label}`).join(' | ') + ' |';
-	const sep = '| --- |' + browsers.map(() => ' ---: |').join('');
+	const floor_versions = browser_versions_for(runtime_floor);
 
-	const body = sorted.map((entry) => {
-		const cells = browsers.map(([key]) => {
-			const v = entry.versions[key];
+	const rows: string[][] = [];
+	for (const row of features) {
+		const name_cell = row.doc_link ? `[${row.name}](${row.doc_link})` : row.name;
+		const versions = browsers.map(([key]) => {
+			const v = row.versions[key];
 			if (v === null) return 'not supported';
 			if (v === undefined) return '<span style="color: var(--sk-fg-4)">—</span>';
-			const floor_v = runtime_versions[key];
-			return floor_v && Number(v) <= Number(floor_v)
-				? '<span style="color: var(--sk-fg-4)">—</span>'
-				: v;
+			const floor_v = floor_versions[key];
+			if (floor_v && Number(v) <= Number(floor_v))
+				return '<span style="color: var(--sk-fg-4)">—</span>';
+
+			return v;
 		});
-		return `| ${entry.name} | ${cells.join(' | ')} |`;
-	});
+		rows.push([name_cell, ...versions]);
+	}
 
-	return [header, sep, ...body].join('\n');
+	return render_markdown_table(['Feature', ...browsers.map(([, label]) => `${label}`)], rows);
 }
 
 function browser_versions_for(target: RuntimeFloor): Record<string, string> {
@@ -750,53 +750,59 @@ function browser_versions_for(target: RuntimeFloor): Record<string, string> {
 	return lookup;
 }
 
-function render_table(versions: Record<string, string>, target: RuntimeFloor): string {
-	// Chrome and Edge ship from the same engine and historically resolve to the
-	// same Baseline version. Collapse them into one row when they match, but
-	// fall back to listing them separately if they ever drift.
-	const chrome_edge: [string, string] | null =
-		versions.chrome && versions.chrome === versions.edge ? ['Chrome/Edge', versions.chrome] : null;
-
-	const base_rows: Array<[string, string]> = chrome_edge
-		? [chrome_edge, ['Chrome (Android)', versions.chrome_android]]
-		: [
-				['Chrome', versions.chrome],
-				['Chrome (Android)', versions.chrome_android],
-				['Edge', versions.edge]
-			];
-
-	const rows = [
-		...base_rows,
-		['Firefox', versions.firefox],
-		['Firefox (Android)', versions.firefox_android],
-		['Safari', versions.safari],
-		['Safari (iOS)', versions.safari_ios],
-		['Opera', versions.opera],
-		['Opera (Android)', versions.opera_android],
-		['Samsung Internet', versions.samsunginternet_android],
-		['Android WebView', versions.webview_android]
-	].filter(([label, version]) => version !== undefined) as Array<[string, string]>;
-
-	const headings = ['Browser', 'Minimum version'];
-
-	const widths = headings.map((heading, i) =>
-		Math.max(heading.length, ...rows.map((r) => String(r[i]).length))
-	);
+const BROWSER = {
+	chrome: 'Chrome',
+	edge: 'Edge',
+	firefox: 'Firefox',
+	safari: 'Safari',
+	opera: 'Opera',
+	samsung_internet: 'Samsung Internet',
+	webview_android: 'Android WebView',
+	internet_explorer: 'Internet Explorer'
+};
 
-	const pad = (s: string, n: number) => s + ' '.repeat(Math.max(0, n - s.length));
+function render_browser_table(versions: Record<string, string>, target: RuntimeFloor): string {
+	const rows: Array<[string, string]> = [
+		[BROWSER.chrome, versions.chrome],
+		[`${BROWSER.chrome} (Android)`, versions.chrome_android]
+	];
 
-	const header = `| ${headings.map((heading, i) => pad(heading, widths[i])).join(' | ')} |`;
-	const sep = `| ${widths.map((width) => '-'.repeat(width)).join(' | ')} |`;
-	const body = rows
-		.map(([a, b]) => `| ${pad(a, widths[0])} | ${pad(String(b), widths[1])} |`)
-		.join('\n');
+	if (versions.chrome === versions.edge) {
+		rows[0][0] += `/${BROWSER.edge}`;
+	} else {
+		rows.push([BROWSER.edge, versions.edge]);
+	}
+
+	rows.push(
+		[BROWSER.firefox, versions.firefox],
+		[`${BROWSER.firefox} (Android)`, versions.firefox_android],
+		[BROWSER.safari, versions.safari],
+		[`${BROWSER.safari} (iOS)`, versions.safari_ios],
+		[BROWSER.opera, versions.opera],
+		[`${BROWSER.opera} (Android)`, versions.opera_android],
+		[BROWSER.samsung_internet, versions.samsunginternet_android],
+		[BROWSER.webview_android, versions.webview_android],
+		[BROWSER.internet_explorer, 'not supported']
+	);
 
 	const target_label = target === 'newly' ? '"newly available"' : target;
 
-	return `${header}\n${sep}\n${body}\n\n> [!NOTE] This equates to a <a href="https://web-platform-dx.github.io/baseline/">Baseline</a> target of ${target_label}.`;
+	return (
+		render_markdown_table(
+			['Browser', 'Minimum version'],
+			rows.filter(([, version]) => version !== undefined)
+		) +
+		`\n\n> [!NOTE] This equates to a <a href="https://web-platform-dx.github.io/baseline/">Baseline</a> target of ${target_label}.`
+	);
+}
+
+function render_markdown_table(headers: string[], rows: string[][]): string {
+	return `| ${headers.join(' | ')} |
+| ${headers.map(() => '-').join(' | ')} |
+${rows.map((row) => `| ${row.join(' | ')} |`).join('\n')}
+`;
 }
 
-/* eslint-disable no-console */
 async function main() {
 	console.log('Preparing scratch directory…');
 	// Wipe and recreate so stale bundles can't leak into the next scan.
@@ -844,14 +850,11 @@ async function main() {
 		const versions = browser_versions_for(target);
 
 		console.log('Rewriting docs page…');
-		generate('browser-support.md', render_table(versions, target));
+		generate('browser-support.md', render_browser_table(versions, target));
 		generate('browser-support-features.md', render_conditional_table(conditional_rows, target));
 
 		console.log('Done.');
 	} finally {
-		// Ensure cleanup happens even on failure — otherwise leftover bundle
-		// files in `scripts/_baseline/` get picked up by `pnpm lint` on the
-		// next CI step and produce spurious naming/no-console errors.
 		fs.rmSync(tmp_dir, { recursive: true, force: true });
 	}
 }

From 2f6307af65fdecce9e7f37ce78464d9431b266ce Mon Sep 17 00:00:00 2001
From: jiyujie2006 <49909156+jiyujie2006@users.noreply.github.com>
Date: Mon, 1 Jun 2026 00:07:28 +0800
Subject: [PATCH 065/222] Fix searchParams.set duplicate updates (#18336)

## Summary
- detect `SvelteURLSearchParams#set` changes by comparing duplicate
value lists instead of joined strings
- update reactive subscribers when duplicate params collapse to a single
value with the same concatenated text
- cover both `SvelteURLSearchParams` and `SvelteURL.searchParams`
synchronization

## Tests
- pnpm exec vitest run
packages/svelte/src/reactivity/url-search-params.test.ts -t
"URLSearchParams.set updates when duplicate values collapse to the same
joined string"
- pnpm exec vitest run
packages/svelte/src/reactivity/url-search-params.test.ts
packages/svelte/src/reactivity/url.test.ts

---------

Co-authored-by: Rich Harris <hello@rich-harris.dev>
---
 .changeset/search-params-duplicate-set.md     |  5 +++
 .../src/reactivity/url-search-params.js       |  5 ++-
 .../src/reactivity/url-search-params.test.ts  | 38 +++++++++++++++++++
 packages/svelte/src/reactivity/url.test.ts    | 19 ++++++++++
 4 files changed, 65 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/search-params-duplicate-set.md

diff --git a/.changeset/search-params-duplicate-set.md b/.changeset/search-params-duplicate-set.md
new file mode 100644
index 0000000000..9fcaa8b289
--- /dev/null
+++ b/.changeset/search-params-duplicate-set.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: update `SvelteURLSearchParams` when setting duplicate keys to the same joined value
diff --git a/packages/svelte/src/reactivity/url-search-params.js b/packages/svelte/src/reactivity/url-search-params.js
index 2e70bf518d..38cf3ebe4f 100644
--- a/packages/svelte/src/reactivity/url-search-params.js
+++ b/packages/svelte/src/reactivity/url-search-params.js
@@ -132,11 +132,12 @@ export class SvelteURLSearchParams extends URLSearchParams {
 	 * @returns {void}
 	 */
 	set(name, value) {
-		var previous = super.getAll(name).join('');
+		var previous = super.getAll(name);
 		super.set(name, value);
 		// can't use has(name, value), because for something like https://svelte.dev?foo=1&bar=2&foo=3
 		// if you set `foo` to 1, then foo=3 gets deleted whilst `has("foo", "1")` returns true
-		if (previous !== super.getAll(name).join('')) {
+		var current = super.getAll(name);
+		if (previous.length !== current.length || previous.some((value, i) => value !== current[i])) {
 			this.#update_url();
 			increment(this.#version);
 		}
diff --git a/packages/svelte/src/reactivity/url-search-params.test.ts b/packages/svelte/src/reactivity/url-search-params.test.ts
index 27a413a553..b0c84872b0 100644
--- a/packages/svelte/src/reactivity/url-search-params.test.ts
+++ b/packages/svelte/src/reactivity/url-search-params.test.ts
@@ -55,6 +55,44 @@ test('URLSearchParams.set', () => {
 	cleanup();
 });
 
+test('URLSearchParams.set updates when duplicate values collapse to the same joined string', () => {
+	const params = new SvelteURLSearchParams('a=ab&a=c');
+	const log: any = [];
+
+	const cleanup = effect_root(() => {
+		render_effect(() => {
+			log.push(params.toString());
+		});
+	});
+
+	flushSync(() => {
+		params.set('a', 'abc');
+	});
+
+	assert.deepEqual(log, ['a=ab&a=c', 'a=abc']);
+
+	cleanup();
+});
+
+test('URLSearchParams.set updates when duplicate values collapse to the same comma-joined string', () => {
+	const params = new SvelteURLSearchParams('a=a&a=b');
+	const log: any = [];
+
+	const cleanup = effect_root(() => {
+		render_effect(() => {
+			log.push(params.toString());
+		});
+	});
+
+	flushSync(() => {
+		params.set('a', 'a,b');
+	});
+
+	assert.deepEqual(log, ['a=a&a=b', 'a=a%2Cb']);
+
+	cleanup();
+});
+
 test('URLSearchParams.append', () => {
 	const params = new SvelteURLSearchParams();
 	const log: any = [];
diff --git a/packages/svelte/src/reactivity/url.test.ts b/packages/svelte/src/reactivity/url.test.ts
index a76efeb2b2..a79aa32315 100644
--- a/packages/svelte/src/reactivity/url.test.ts
+++ b/packages/svelte/src/reactivity/url.test.ts
@@ -115,6 +115,25 @@ test('url.searchParams', () => {
 	cleanup();
 });
 
+test('url.searchParams.set updates url when duplicate values collapse to the same joined string', () => {
+	const url = new SvelteURL('https://svelte.dev?a=ab&a=c');
+	const log: any = [];
+
+	const cleanup = effect_root(() => {
+		render_effect(() => {
+			log.push(url.href);
+		});
+	});
+
+	flushSync(() => {
+		url.searchParams.set('a', 'abc');
+	});
+
+	assert.deepEqual(log, ['https://svelte.dev/?a=ab&a=c', 'https://svelte.dev/?a=abc']);
+
+	cleanup();
+});
+
 test('url.search normalizes value', () => {
 	const url = new SvelteURL('https://svelte.dev');
 	const log: any = [];

From 378bb25097088c2277aa063408c62818cc1f6c4e Mon Sep 17 00:00:00 2001
From: jdoughty04 <jonathandoughty04@gmail.com>
Date: Sun, 31 May 2026 12:16:37 -0400
Subject: [PATCH 066/222] fix: set input type before spread value (#18345)

### Before submitting the PR, please make sure you do the following

- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).

### Tests and linting

- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`

Fixes #18332.

When spread props put `value` before a later `type="hidden"` on an
`<input>`, `set_attributes` currently writes the value while the element
is still a text input. Browsers sanitize text input values by removing
newlines, so the hidden input permanently loses them before `type` is
applied.

This sets an input's `type` first whenever the same spread update also
includes `value` or `__value`, so the existing value handling runs with
the final input type. The new runtime-browser sample covers both the
problematic spread-first order and the already-working type-first order.

Validation:

- `corepack pnpm lint`
- `CI=1 corepack pnpm test`
- `corepack pnpm vitest run
packages/svelte/tests/runtime-browser/test.ts -t
input-type-before-value-spread`

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
Co-authored-by: Rich Harris <hello@rich-harris.dev>
---
 .changeset/input-type-before-value.md             |  5 +++++
 .../internal/client/dom/elements/attributes.js    |  9 +++++++++
 .../input-type-before-value-spread/_config.js     | 15 +++++++++++++++
 .../input-type-before-value-spread/main.svelte    |  7 +++++++
 4 files changed, 36 insertions(+)
 create mode 100644 .changeset/input-type-before-value.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/input-type-before-value-spread/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/input-type-before-value-spread/main.svelte

diff --git a/.changeset/input-type-before-value.md b/.changeset/input-type-before-value.md
new file mode 100644
index 0000000000..68d02f920f
--- /dev/null
+++ b/.changeset/input-type-before-value.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: preserve newlines in spread input values when the `type` attribute is applied after `value`
diff --git a/packages/svelte/src/internal/client/dom/elements/attributes.js b/packages/svelte/src/internal/client/dom/elements/attributes.js
index a193a70dd5..589685b5f2 100644
--- a/packages/svelte/src/internal/client/dom/elements/attributes.js
+++ b/packages/svelte/src/internal/client/dom/elements/attributes.js
@@ -332,6 +332,15 @@ function set_attributes(
 
 	var setters = get_setters(element);
 
+	if (element.nodeName === INPUT_TAG && 'type' in next && ('value' in next || '__value' in next)) {
+		var type = next.type;
+
+		if (type !== current.type || (type === undefined && element.hasAttribute('type'))) {
+			current.type = type;
+			set_attribute(element, 'type', type, skip_warning);
+		}
+	}
+
 	// since key is captured we use const
 	for (const key in next) {
 		// let instead of var because referenced in a closure
diff --git a/packages/svelte/tests/runtime-runes/samples/input-type-before-value-spread/_config.js b/packages/svelte/tests/runtime-runes/samples/input-type-before-value-spread/_config.js
new file mode 100644
index 0000000000..7aeaf38eb0
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/input-type-before-value-spread/_config.js
@@ -0,0 +1,15 @@
+import { test } from '../../test';
+
+const value = 'line1\nline2\nline3';
+
+export default test({
+	mode: ['client'],
+	test({ assert, target }) {
+		const [spread_first, type_first] = target.querySelectorAll('input');
+
+		assert.equal(spread_first?.type, 'hidden');
+		assert.equal(spread_first?.value, value);
+		assert.equal(type_first?.type, 'hidden');
+		assert.equal(type_first?.value, value);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/input-type-before-value-spread/main.svelte b/packages/svelte/tests/runtime-runes/samples/input-type-before-value-spread/main.svelte
new file mode 100644
index 0000000000..16e72ab704
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/input-type-before-value-spread/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	const value = 'line1\nline2\nline3';
+	const spread = { name: 'field', value };
+</script>
+
+<input {...spread} type="hidden" />
+<input type="hidden" {...spread} />

From b76b937e0053b7368b9a94bf2b351b181bd2eda6 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Mon, 1 Jun 2026 03:59:37 -0400
Subject: [PATCH 067/222] fix: various declaration tag bugs (#18348)

closes #18334
---
 .../declaration-tag-multiple-declarators.md     |  5 +++++
 .../declaration-tag-state-referenced-locally.md |  5 +++++
 .changeset/declaration-tag-whitespace.md        |  5 +++++
 .../phases/2-analyze/visitors/DeclarationTag.js |  6 ++++--
 .../client/visitors/DeclarationTag.js           |  4 +++-
 .../_config.js                                  | 17 +++++++++++++++++
 .../main.svelte                                 | 10 ++++++++++
 .../input.svelte                                |  9 +++++++++
 .../warnings.json                               | 14 ++++++++++++++
 9 files changed, 72 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/declaration-tag-multiple-declarators.md
 create mode 100644 .changeset/declaration-tag-state-referenced-locally.md
 create mode 100644 .changeset/declaration-tag-whitespace.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/declaration-tag-multiple-declarators/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/declaration-tag-multiple-declarators/main.svelte
 create mode 100644 packages/svelte/tests/validator/samples/declaration-tag-state-referenced-locally/input.svelte
 create mode 100644 packages/svelte/tests/validator/samples/declaration-tag-state-referenced-locally/warnings.json

diff --git a/.changeset/declaration-tag-multiple-declarators.md b/.changeset/declaration-tag-multiple-declarators.md
new file mode 100644
index 0000000000..3f17162b54
--- /dev/null
+++ b/.changeset/declaration-tag-multiple-declarators.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: correctly transform references to earlier declarators in a declaration tag (e.g. `{let a = $state(0), b = $derived(a * 2)}`)
diff --git a/.changeset/declaration-tag-state-referenced-locally.md b/.changeset/declaration-tag-state-referenced-locally.md
new file mode 100644
index 0000000000..00803c3e1c
--- /dev/null
+++ b/.changeset/declaration-tag-state-referenced-locally.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: avoid spurious `state_referenced_locally` warnings for `$derived` declarations in declaration tags
diff --git a/.changeset/declaration-tag-whitespace.md b/.changeset/declaration-tag-whitespace.md
new file mode 100644
index 0000000000..b64d1dd5a1
--- /dev/null
+++ b/.changeset/declaration-tag-whitespace.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: tolerate whitespace before `let`/`const` in declaration tags
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/DeclarationTag.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/DeclarationTag.js
index e75c05f355..b5e8c931f1 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/DeclarationTag.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/DeclarationTag.js
@@ -2,14 +2,12 @@
 /** @import { Context } from '../types' */
 import * as b from '#compiler/builders';
 import * as e from '../../../errors.js';
-import { validate_opening_tag } from './shared/utils.js';
 
 /**
  * @param {AST.DeclarationTag} node
  * @param {Context} context
  */
 export function DeclarationTag(node, context) {
-	validate_opening_tag(node, context.state, node.declaration.kind[0]);
 	if (!context.state.analysis.runes && !context.state.analysis.maybe_runes) {
 		e.declaration_tag_no_legacy_mode(node);
 	}
@@ -17,6 +15,10 @@ export function DeclarationTag(node, context) {
 	context.visit(node.declaration, {
 		...context.state,
 		in_declaration_tag: true,
+		// the declaration lives in the fragment scope, which is one level deeper than the
+		// `function_depth` we're tracking here (`set_scope` doesn't update `function_depth`).
+		// align them so that `state_referenced_locally` warnings are calculated correctly
+		function_depth: context.state.scope.function_depth,
 		expression: node.metadata.expression
 	});
 
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/DeclarationTag.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/DeclarationTag.js
index bff51b20dd..abec5e828f 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/DeclarationTag.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/DeclarationTag.js
@@ -10,8 +10,10 @@ import { add_state_transformers } from './shared/declarations.js';
  * @param {ComponentContext} context
  */
 export function DeclarationTag(node, context) {
-	const declaration = /** @type {Statement | undefined} */ (context.visit(node.declaration));
+	// register the transformers _before_ visiting the declaration, so that
+	// later declarators can reference earlier ones (e.g. `{let a = $state(0), b = $derived(a * 2)}`)
 	add_state_transformers(context);
+	const declaration = /** @type {Statement | undefined} */ (context.visit(node.declaration));
 
 	if (
 		node.metadata.promises_id &&
diff --git a/packages/svelte/tests/runtime-runes/samples/declaration-tag-multiple-declarators/_config.js b/packages/svelte/tests/runtime-runes/samples/declaration-tag-multiple-declarators/_config.js
new file mode 100644
index 0000000000..c5846ba0bc
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/declaration-tag-multiple-declarators/_config.js
@@ -0,0 +1,17 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	html: `<button>increment</button><p>count: 0</p><p>doubled: 0</p><p>quadrupled: 0</p>`,
+	async test({ assert, target }) {
+		const [button] = target.querySelectorAll('button');
+
+		button.click();
+		await tick();
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`<button>increment</button><p>count: 1</p><p>doubled: 2</p><p>quadrupled: 4</p>`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/declaration-tag-multiple-declarators/main.svelte b/packages/svelte/tests/runtime-runes/samples/declaration-tag-multiple-declarators/main.svelte
new file mode 100644
index 0000000000..d6fb542396
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/declaration-tag-multiple-declarators/main.svelte
@@ -0,0 +1,10 @@
+<!-- a later declarator can reference an earlier one within the same tag... -->
+{let count = $state(0), doubled = $derived(count * 2)}
+
+<!-- ...and leading whitespace is tolerated -->
+{ let quadrupled = $derived(doubled * 2) }
+
+<button onclick={() => (count += 1)}>increment</button>
+<p>count: {count}</p>
+<p>doubled: {doubled}</p>
+<p>quadrupled: {quadrupled}</p>
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-state-referenced-locally/input.svelte b/packages/svelte/tests/validator/samples/declaration-tag-state-referenced-locally/input.svelte
new file mode 100644
index 0000000000..90cc208e72
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/declaration-tag-state-referenced-locally/input.svelte
@@ -0,0 +1,9 @@
+<!-- `$derived` reads happen inside a closure, so these should _not_ warn -->
+{let a = $state(0), b = $derived(a * 2)}
+{let c = $state(0)}
+{let d = $derived(c * 2)}
+
+<!-- this is a non-closure read of state, so it _should_ warn -->
+{let e = $state(0), f = e}
+
+{a}{b}{c}{d}{e}{f}
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-state-referenced-locally/warnings.json b/packages/svelte/tests/validator/samples/declaration-tag-state-referenced-locally/warnings.json
new file mode 100644
index 0000000000..9b87a3afb6
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/declaration-tag-state-referenced-locally/warnings.json
@@ -0,0 +1,14 @@
+[
+	{
+		"code": "state_referenced_locally",
+		"message": "This reference only captures the initial value of `e`. Did you mean to reference it inside a closure instead?",
+		"start": {
+			"line": 7,
+			"column": 24
+		},
+		"end": {
+			"line": 7,
+			"column": 25
+		}
+	}
+]

From c74f44fff99de06270c26098600f891835a15288 Mon Sep 17 00:00:00 2001
From: Yuichiro Yamashita <xydybaseball@gmail.com>
Date: Mon, 1 Jun 2026 17:03:41 +0900
Subject: [PATCH 068/222] fix: don't mistake `type` identifier expressions for
 TS `type` declarations in tags (#18330)

Detect TypeScript `type` declarations by actually parsing instead of by
character-class blacklists, so that expressions like `{type === 'all' ?
a : b}` or `{type instanceof Foo}` aren't misclassified as malformed
declarations.

Closes #18328

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/fix-type-identifier-in-tag.md      |  5 +
 .../src/compiler/phases/1-parse/state/tag.js  | 29 ++++--
 .../compiler/phases/1-parse/utils/bracket.js  | 11 ++-
 .../loose-declaration-tag/input.svelte        |  1 +
 .../samples/loose-declaration-tag/output.json | 38 +++++++-
 .../input.svelte                              |  1 +
 .../output.json                               | 92 +++++++++++++++++++
 .../errors.json                               |  6 +-
 .../input.svelte                              | 14 +++
 9 files changed, 181 insertions(+), 16 deletions(-)
 create mode 100644 .changeset/fix-type-identifier-in-tag.md
 create mode 100644 packages/svelte/tests/parser-modern/samples/tag-type-identifier-probe-comment/input.svelte
 create mode 100644 packages/svelte/tests/parser-modern/samples/tag-type-identifier-probe-comment/output.json

diff --git a/.changeset/fix-type-identifier-in-tag.md b/.changeset/fix-type-identifier-in-tag.md
new file mode 100644
index 0000000000..90e03da80f
--- /dev/null
+++ b/.changeset/fix-type-identifier-in-tag.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: more robust parsing of declaration tags with regards to `type`
diff --git a/packages/svelte/src/compiler/phases/1-parse/state/tag.js b/packages/svelte/src/compiler/phases/1-parse/state/tag.js
index 3c8eba4b26..15c79e0353 100644
--- a/packages/svelte/src/compiler/phases/1-parse/state/tag.js
+++ b/packages/svelte/src/compiler/phases/1-parse/state/tag.js
@@ -12,9 +12,9 @@ import { find_matching_bracket, match_bracket } from '../utils/bracket.js';
 
 const regex_whitespace_with_closing_curly_brace = /\s*}/y;
 const regex_supported_declaration = /(?:let|const)\b/y;
-// All except `type` are reserved keywords and cannot be used as variable names.
-// For type we check if it's not something like `type .x` / `type ()` / `type % 2` / ...
-const regex_unsupported_declaration = /(?:(?:var|interface|enum)\b)|(?:type\s+[^?.(`<[&|%^}])/y;
+const regex_unsupported_declaration = /(?:var|interface|enum)\b/y;
+// `type` is a contextual keyword; this is just a shape hint, confirmed by parsing.
+const regex_maybe_type_declaration = /type\b/y;
 
 const pointy_bois = { '<': '>' };
 
@@ -77,10 +77,17 @@ function read_declaration(parser) {
 		e.declaration_tag_invalid_type({ start, end: start + unsupported.length });
 	}
 
-	if (!parser.match_regex(regex_supported_declaration)) {
+	if (
+		!parser.match_regex(regex_supported_declaration) &&
+		// `type` is special, since it is not a reserved keyword and can be used
+		// as part of a valid expression. We gotta parse first and then see what it is.
+		!parser.match_regex(regex_maybe_type_declaration)
+	) {
 		return null;
 	}
 
+	const initial_comment_count = parser.root.comments.length;
+
 	/** @type {import('estree').Statement | import('estree').VariableDeclaration} */
 	let declaration;
 	try {
@@ -117,10 +124,16 @@ function read_declaration(parser) {
 	}
 
 	if (declaration.type !== 'VariableDeclaration') {
-		e.declaration_tag_invalid_type({
-			start: declaration.start ?? start,
-			end: declaration.end ?? parser.index
-		});
+		if (declaration.type === 'ExpressionStatement') {
+			parser.root.comments.length = initial_comment_count; // Else they show up duplicated
+			return null;
+		} else {
+			// This is a TSTypeAliasDeclaration
+			e.declaration_tag_invalid_type({
+				start: declaration.start ?? start,
+				end: declaration.end ?? parser.index
+			});
+		}
 	}
 
 	// TODO support using
diff --git a/packages/svelte/src/compiler/phases/1-parse/utils/bracket.js b/packages/svelte/src/compiler/phases/1-parse/utils/bracket.js
index 63fbc68fb3..567d999a59 100644
--- a/packages/svelte/src/compiler/phases/1-parse/utils/bracket.js
+++ b/packages/svelte/src/compiler/phases/1-parse/utils/bracket.js
@@ -39,7 +39,9 @@ function find_string_end(string, search_start_index, string_start_char) {
  * @returns {number} The index of the end of this regex expression, or `Infinity` if not found.
  */
 function find_regex_end(string, search_start_index) {
-	return find_unescaped_char(string, search_start_index, '/');
+	const slash = find_unescaped_char(string, search_start_index, '/');
+	const eol = find_unescaped_char(string, search_start_index, '\n');
+	return slash < eol ? slash : Infinity;
 }
 
 /**
@@ -114,7 +116,12 @@ export function find_matching_bracket(template, index, open) {
 					i = infinity_if_negative(template.indexOf('*/', i + 1)) + '*/'.length;
 					continue;
 				}
-				i = find_regex_end(template, i + 1) + '/'.length;
+				const end = find_regex_end(template, i + 1) + '/'.length;
+				if (end === Infinity) {
+					i++;
+				} else {
+					i = end;
+				}
 				continue;
 			}
 			default: {
diff --git a/packages/svelte/tests/parser-modern/samples/loose-declaration-tag/input.svelte b/packages/svelte/tests/parser-modern/samples/loose-declaration-tag/input.svelte
index f222531638..036d5283f5 100644
--- a/packages/svelte/tests/parser-modern/samples/loose-declaration-tag/input.svelte
+++ b/packages/svelte/tests/parser-modern/samples/loose-declaration-tag/input.svelte
@@ -1,4 +1,5 @@
 {#if true}
 	{let }
 	{const x = }
+	{let x = a / }
 {/if}
diff --git a/packages/svelte/tests/parser-modern/samples/loose-declaration-tag/output.json b/packages/svelte/tests/parser-modern/samples/loose-declaration-tag/output.json
index 882e5f34f1..270d16af94 100644
--- a/packages/svelte/tests/parser-modern/samples/loose-declaration-tag/output.json
+++ b/packages/svelte/tests/parser-modern/samples/loose-declaration-tag/output.json
@@ -2,7 +2,7 @@
 	"css": null,
 	"js": [],
 	"start": 0,
-	"end": 38,
+	"end": 54,
 	"type": "Root",
 	"fragment": {
 		"type": "Fragment",
@@ -11,7 +11,7 @@
 				"type": "IfBlock",
 				"elseif": false,
 				"start": 0,
-				"end": 38,
+				"end": 54,
 				"test": {
 					"type": "Literal",
 					"start": 5,
@@ -99,7 +99,39 @@
 						{
 							"type": "Text",
 							"start": 32,
-							"end": 33,
+							"end": 34,
+							"raw": "\n\t",
+							"data": "\n\t"
+						},
+						{
+							"type": "DeclarationTag",
+							"start": 34,
+							"end": 48,
+							"declaration": {
+								"type": "VariableDeclaration",
+								"kind": "let",
+								"declarations": [
+									{
+										"type": "VariableDeclarator",
+										"id": {
+											"type": "Identifier",
+											"name": "",
+											"start": 47,
+											"end": 47
+										},
+										"init": null,
+										"start": 47,
+										"end": 47
+									}
+								],
+								"start": 35,
+								"end": 47
+							}
+						},
+						{
+							"type": "Text",
+							"start": 48,
+							"end": 49,
 							"raw": "\n",
 							"data": "\n"
 						}
diff --git a/packages/svelte/tests/parser-modern/samples/tag-type-identifier-probe-comment/input.svelte b/packages/svelte/tests/parser-modern/samples/tag-type-identifier-probe-comment/input.svelte
new file mode 100644
index 0000000000..fa4195996e
--- /dev/null
+++ b/packages/svelte/tests/parser-modern/samples/tag-type-identifier-probe-comment/input.svelte
@@ -0,0 +1 @@
+{type instanceof /* probe */ Object}
diff --git a/packages/svelte/tests/parser-modern/samples/tag-type-identifier-probe-comment/output.json b/packages/svelte/tests/parser-modern/samples/tag-type-identifier-probe-comment/output.json
new file mode 100644
index 0000000000..4fe6468742
--- /dev/null
+++ b/packages/svelte/tests/parser-modern/samples/tag-type-identifier-probe-comment/output.json
@@ -0,0 +1,92 @@
+{
+	"css": null,
+	"js": [],
+	"start": 0,
+	"end": 36,
+	"type": "Root",
+	"fragment": {
+		"type": "Fragment",
+		"nodes": [
+			{
+				"type": "ExpressionTag",
+				"start": 0,
+				"end": 36,
+				"expression": {
+					"type": "BinaryExpression",
+					"start": 1,
+					"end": 35,
+					"loc": {
+						"start": {
+							"line": 1,
+							"column": 1
+						},
+						"end": {
+							"line": 1,
+							"column": 35
+						}
+					},
+					"left": {
+						"type": "Identifier",
+						"start": 1,
+						"end": 5,
+						"loc": {
+							"start": {
+								"line": 1,
+								"column": 1
+							},
+							"end": {
+								"line": 1,
+								"column": 5
+							}
+						},
+						"name": "type"
+					},
+					"operator": "instanceof",
+					"right": {
+						"type": "Identifier",
+						"start": 29,
+						"end": 35,
+						"loc": {
+							"start": {
+								"line": 1,
+								"column": 29
+							},
+							"end": {
+								"line": 1,
+								"column": 35
+							}
+						},
+						"name": "Object",
+						"leadingComments": [
+							{
+								"type": "Block",
+								"value": " probe ",
+								"start": 17,
+								"end": 28
+							}
+						]
+					}
+				}
+			}
+		]
+	},
+	"options": null,
+	"comments": [
+		{
+			"type": "Block",
+			"value": " probe ",
+			"start": 17,
+			"end": 28,
+			"loc": {
+				"start": {
+					"line": 1,
+					"column": 17
+				},
+				"end": {
+					"line": 1,
+					"column": 28
+				}
+			}
+		}
+	]
+}
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-invalid-type-2/errors.json b/packages/svelte/tests/validator/samples/declaration-tag-invalid-type-2/errors.json
index 052636cddb..a375ac5776 100644
--- a/packages/svelte/tests/validator/samples/declaration-tag-invalid-type-2/errors.json
+++ b/packages/svelte/tests/validator/samples/declaration-tag-invalid-type-2/errors.json
@@ -3,12 +3,12 @@
 		"code": "declaration_tag_invalid_type",
 		"message": "Declaration tags must be `let` or `const` declarations",
 		"start": {
-			"line": 14,
+			"line": 28,
 			"column": 2
 		},
 		"end": {
-			"line": 14,
-			"column": 8
+			"line": 28,
+			"column": 20
 		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-invalid-type-2/input.svelte b/packages/svelte/tests/validator/samples/declaration-tag-invalid-type-2/input.svelte
index 129a8ac7ba..88295cad58 100644
--- a/packages/svelte/tests/validator/samples/declaration-tag-invalid-type-2/input.svelte
+++ b/packages/svelte/tests/validator/samples/declaration-tag-invalid-type-2/input.svelte
@@ -1,3 +1,5 @@
+<script lang="ts"></script>
+
 {#if true}
 	<!-- check that these doesn't trigger already -->
 	{type}
@@ -10,6 +12,18 @@
 	{type ()}
 	{type [1]}
 	{type `tag`}
+	{type === 'all' ? 'All types' : type}
+	{type !== 'all'}
+	{type == 'all'}
+	{type != 'all'}
+	{type + 1}
+	{type - 1}
+	{type * 2}
+	{type / 2}
+	{type > 1}
+	{type instanceof Foo}
+	{type instanceof /* comment */ Object}
+	{type in foo}
 	<!-- ... this one should trigger though -->
 	{type foo = boolean}
 {/if}

From b471c15e61c90f820f0e059cfe90d56c135a8e3f Mon Sep 17 00:00:00 2001
From: Yuichiro Yamashita <xydybaseball@gmail.com>
Date: Mon, 1 Jun 2026 17:03:59 +0900
Subject: [PATCH 069/222] fix: don't hang on a tag whose expression ends with a
 trailing slash (#18350)

close https://github.com/sveltejs/svelte/issues/18349
---
 .changeset/fix-find-matching-bracket-infinite-loop.md |  5 +++++
 .../src/compiler/phases/1-parse/utils/bracket.js      |  6 +++++-
 .../samples/declaration-tag-trailing-slash/_config.js | 11 +++++++++++
 .../declaration-tag-trailing-slash/main.svelte        |  1 +
 4 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/fix-find-matching-bracket-infinite-loop.md
 create mode 100644 packages/svelte/tests/compiler-errors/samples/declaration-tag-trailing-slash/_config.js
 create mode 100644 packages/svelte/tests/compiler-errors/samples/declaration-tag-trailing-slash/main.svelte

diff --git a/.changeset/fix-find-matching-bracket-infinite-loop.md b/.changeset/fix-find-matching-bracket-infinite-loop.md
new file mode 100644
index 0000000000..c0656ea794
--- /dev/null
+++ b/.changeset/fix-find-matching-bracket-infinite-loop.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: prevent infinite loop when a tag's expression ends with a trailing `/` at the end of the input
diff --git a/packages/svelte/src/compiler/phases/1-parse/utils/bracket.js b/packages/svelte/src/compiler/phases/1-parse/utils/bracket.js
index 567d999a59..47299c9de5 100644
--- a/packages/svelte/src/compiler/phases/1-parse/utils/bracket.js
+++ b/packages/svelte/src/compiler/phases/1-parse/utils/bracket.js
@@ -107,7 +107,11 @@ export function find_matching_bracket(template, index, open) {
 				continue;
 			case '/': {
 				const next_char = template[i + 1];
-				if (!next_char) continue;
+				if (!next_char) {
+					// `/` is the last character; advance past it so we don't loop forever
+					i++;
+					continue;
+				}
 				if (next_char === '/') {
 					i = infinity_if_negative(template.indexOf('\n', i + 1)) + '\n'.length;
 					continue;
diff --git a/packages/svelte/tests/compiler-errors/samples/declaration-tag-trailing-slash/_config.js b/packages/svelte/tests/compiler-errors/samples/declaration-tag-trailing-slash/_config.js
new file mode 100644
index 0000000000..2e605631c5
--- /dev/null
+++ b/packages/svelte/tests/compiler-errors/samples/declaration-tag-trailing-slash/_config.js
@@ -0,0 +1,11 @@
+import { test } from '../../test';
+
+// A tag whose expression ends with a bare `/` at the end of the input used to
+// make `find_matching_bracket` loop forever; it should error instead of hanging.
+export default test({
+	error: {
+		code: 'unexpected_eof',
+		message: 'Unexpected end of input',
+		position: [12, 12]
+	}
+});
diff --git a/packages/svelte/tests/compiler-errors/samples/declaration-tag-trailing-slash/main.svelte b/packages/svelte/tests/compiler-errors/samples/declaration-tag-trailing-slash/main.svelte
new file mode 100644
index 0000000000..8ffdb88a18
--- /dev/null
+++ b/packages/svelte/tests/compiler-errors/samples/declaration-tag-trailing-slash/main.svelte
@@ -0,0 +1 @@
+{let x = a /
\ No newline at end of file

From 2afb895ffabe918d69f8463e06637b060b7a4dce Mon Sep 17 00:00:00 2001
From: hjaber <41503068+hjaber@users.noreply.github.com>
Date: Mon, 1 Jun 2026 14:36:18 -0700
Subject: [PATCH 070/222] fix: parse declaration tags with a division operator
 in the initializer (#18353)

Mimic what `parseExpressionAt` does

---------

Co-authored-by: hjaber <hjaber@users.noreply.github.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/declaration-tag-division.md        |  5 +++
 .../src/compiler/phases/1-parse/acorn.js      | 45 +++++++------------
 .../declaration-tag-division/input.svelte     | 20 +++++++++
 .../declaration-tag-division/output.svelte    | 20 +++++++++
 4 files changed, 61 insertions(+), 29 deletions(-)
 create mode 100644 .changeset/declaration-tag-division.md
 create mode 100644 packages/svelte/tests/print/samples/declaration-tag-division/input.svelte
 create mode 100644 packages/svelte/tests/print/samples/declaration-tag-division/output.svelte

diff --git a/.changeset/declaration-tag-division.md b/.changeset/declaration-tag-division.md
new file mode 100644
index 0000000000..de265f0ab1
--- /dev/null
+++ b/.changeset/declaration-tag-division.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: parse declaration tag contents more robustly
diff --git a/packages/svelte/src/compiler/phases/1-parse/acorn.js b/packages/svelte/src/compiler/phases/1-parse/acorn.js
index d338f9ffb8..fb60c228c5 100644
--- a/packages/svelte/src/compiler/phases/1-parse/acorn.js
+++ b/packages/svelte/src/compiler/phases/1-parse/acorn.js
@@ -5,7 +5,6 @@ import * as acorn from 'acorn';
 import { walk } from 'zimmerframe';
 import { tsPlugin } from '@sveltejs/acorn-typescript';
 import * as e from '../../errors.js';
-import { find_matching_bracket } from './utils/bracket.js';
 
 const JSParser = acorn.Parser;
 const TSParser = JSParser.extend(tsPlugin());
@@ -106,38 +105,26 @@ export function parse_expression_at(parser, source, index) {
  * @returns {Statement}
  */
 export function parse_statement_at(parser, source, index) {
-	const acorn = parser.ts ? TSParser : JSParser;
-	let end = find_matching_bracket(source, index, '{');
-	if (end === undefined) e.unexpected_eof(source.length);
-
-	while (source[end - 1] === ';') {
-		end -= 1;
-	}
-
-	const padded_source = `${' '.repeat(index)}${source.slice(index, end)}`;
-	const { onComment, add_comments } = get_comment_handlers(
-		padded_source,
-		parser.root.comments,
-		index
-	);
+	// cast to `any`: acorn's Parser constructor and parseStatement/nextToken aren't in its public types
+	const acorn = /** @type {any} */ (parser.ts ? TSParser : JSParser);
+	const { onComment, add_comments } = get_comment_handlers(source, parser.root.comments, index);
 
 	try {
-		const ast = acorn.parse(padded_source, {
-			onComment,
-			sourceType: 'module',
-			ecmaVersion: 16,
-			locations: true
-		});
-
-		add_comments(ast);
-
-		const statement = /** @type {Statement} */ (
-			/** @type {unknown} */ (/** @type {Program} */ (ast).body[0])
+		// This is like parseExpressionAt but for statements
+		const p = new acorn(
+			{ onComment, sourceType: 'module', ecmaVersion: 16, locations: true },
+			source,
+			index
 		);
-		statement.end = Math.min(/** @type {number} */ (statement.end), end);
+		p.nextToken();
+		const statement = /** @type {Statement} */ (p.parseStatement(null, true, Object.create(null)));
+		add_comments(/** @type {acorn.Node} */ (statement));
 		return statement;
-	} catch (e) {
-		handle_parse_error(e);
+	} catch (err) {
+		// A statement that runs to the end of the source (e.g. an unterminated declaration tag)
+		// is an EOF, not a stray token; preserve the friendlier `unexpected_eof` diagnostic.
+		if (/** @type {any} */ (err).pos === source.length) e.unexpected_eof(source.length);
+		handle_parse_error(err);
 	}
 }
 
diff --git a/packages/svelte/tests/print/samples/declaration-tag-division/input.svelte b/packages/svelte/tests/print/samples/declaration-tag-division/input.svelte
new file mode 100644
index 0000000000..0e20727748
--- /dev/null
+++ b/packages/svelte/tests/print/samples/declaration-tag-division/input.svelte
@@ -0,0 +1,20 @@
+<script lang="ts">
+	let visible = true;
+	let total = 10;
+	let width = 16;
+	let height = 9;
+	let divisor = 2;
+	let options: { fallback?: number } = {};
+</script>
+
+{#if visible}
+	{const half = total / 2}
+	{let derived = $derived(total / 4)}
+	{const member = width / height}
+	{const call = Math.max(total, 1) / 2}
+	{const string_then_division = 'ab' / divisor}
+	{const typed: number = total / 2}
+	{const { fallback = total / 2 } = options}
+	{const regex = /[}]/}
+	<p>{half} {derived} {member} {call} {string_then_division} {typed} {fallback} {regex}</p>
+{/if}
diff --git a/packages/svelte/tests/print/samples/declaration-tag-division/output.svelte b/packages/svelte/tests/print/samples/declaration-tag-division/output.svelte
new file mode 100644
index 0000000000..0e20727748
--- /dev/null
+++ b/packages/svelte/tests/print/samples/declaration-tag-division/output.svelte
@@ -0,0 +1,20 @@
+<script lang="ts">
+	let visible = true;
+	let total = 10;
+	let width = 16;
+	let height = 9;
+	let divisor = 2;
+	let options: { fallback?: number } = {};
+</script>
+
+{#if visible}
+	{const half = total / 2}
+	{let derived = $derived(total / 4)}
+	{const member = width / height}
+	{const call = Math.max(total, 1) / 2}
+	{const string_then_division = 'ab' / divisor}
+	{const typed: number = total / 2}
+	{const { fallback = total / 2 } = options}
+	{const regex = /[}]/}
+	<p>{half} {derived} {member} {call} {string_then_division} {typed} {fallback} {regex}</p>
+{/if}

From 56013a2c01454388ea5f58642377038f29cdec4a Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Mon, 1 Jun 2026 23:39:50 +0200
Subject: [PATCH 071/222] fix: check references for blockers on server, too
 (#18352)

We forgot the server in #18309

Fixes #18344
---
 .changeset/strong-cups-prove.md                      |  5 +++++
 .../3-transform/server/visitors/shared/utils.js      |  2 +-
 .../Child.svelte                                     |  5 +++++
 .../async-derived-prop-closure-hydration/_config.js  | 11 +++++++++++
 .../async-derived-prop-closure-hydration/main.svelte | 12 ++++++++++++
 5 files changed, 34 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/strong-cups-prove.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-derived-prop-closure-hydration/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-derived-prop-closure-hydration/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-derived-prop-closure-hydration/main.svelte

diff --git a/.changeset/strong-cups-prove.md b/.changeset/strong-cups-prove.md
new file mode 100644
index 0000000000..ad85a1feba
--- /dev/null
+++ b/.changeset/strong-cups-prove.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: check references for blockers on server, too
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
index 62e1c44094..3da6fcf321 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
@@ -343,7 +343,7 @@ export class PromiseOptimiser {
 	 * @param {ExpressionMetadata} metadata
 	 */
 	check_blockers(metadata) {
-		for (const binding of metadata.dependencies) {
+		for (const binding of metadata.references) {
 			if (binding.blocker) {
 				this.#blockers.add(binding.blocker);
 			}
diff --git a/packages/svelte/tests/runtime-runes/samples/async-derived-prop-closure-hydration/Child.svelte b/packages/svelte/tests/runtime-runes/samples/async-derived-prop-closure-hydration/Child.svelte
new file mode 100644
index 0000000000..6e5197b2fe
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-derived-prop-closure-hydration/Child.svelte
@@ -0,0 +1,5 @@
+<script>
+	let { onclick } = $props();
+</script>
+
+<button {onclick}>A button</button>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-derived-prop-closure-hydration/_config.js b/packages/svelte/tests/runtime-runes/samples/async-derived-prop-closure-hydration/_config.js
new file mode 100644
index 0000000000..37a3f0dae1
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-derived-prop-closure-hydration/_config.js
@@ -0,0 +1,11 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['hydrate'],
+
+	async test({ assert, target }) {
+		await tick();
+		assert.htmlEqual(target.innerHTML, 'foo <button>A button</button>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-derived-prop-closure-hydration/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-derived-prop-closure-hydration/main.svelte
new file mode 100644
index 0000000000..c87d3f8a08
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-derived-prop-closure-hydration/main.svelte
@@ -0,0 +1,12 @@
+<script>
+	import Button from './Child.svelte';
+
+	async function getFoo() {
+		return 'foo';
+	}
+
+	const foo = $derived(await getFoo());
+</script>
+
+{foo}
+<Button onclick={() => foo} />

From 5b8db1be35555fee3b938f9d7eab93f2aee48b7e Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Tue, 2 Jun 2026 00:01:39 +0200
Subject: [PATCH 072/222] fix: error at compile time on duplicate
 snippet/declaration tag definitions (#18351)

---
 .changeset/clever-poems-shave.md              |  5 ++++
 .../2-analyze/visitors/DeclarationTag.js      | 11 ++++++++
 .../phases/2-analyze/visitors/SnippetBlock.js | 25 +++++++++++--------
 .../errors.json                               | 14 +++++++++++
 .../input.svelte                              |  5 ++++
 .../snippet-already-declared/errors.json      | 14 +++++++++++
 .../snippet-already-declared/input.svelte     |  5 ++++
 7 files changed, 69 insertions(+), 10 deletions(-)
 create mode 100644 .changeset/clever-poems-shave.md
 create mode 100644 packages/svelte/tests/validator/samples/declaration-tag-already-declared/errors.json
 create mode 100644 packages/svelte/tests/validator/samples/declaration-tag-already-declared/input.svelte
 create mode 100644 packages/svelte/tests/validator/samples/snippet-already-declared/errors.json
 create mode 100644 packages/svelte/tests/validator/samples/snippet-already-declared/input.svelte

diff --git a/.changeset/clever-poems-shave.md b/.changeset/clever-poems-shave.md
new file mode 100644
index 0000000000..252c86b905
--- /dev/null
+++ b/.changeset/clever-poems-shave.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: error at compile time on duplicate snippet/declaration tag definitions
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/DeclarationTag.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/DeclarationTag.js
index b5e8c931f1..52e9480838 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/DeclarationTag.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/DeclarationTag.js
@@ -2,6 +2,7 @@
 /** @import { Context } from '../types' */
 import * as b from '#compiler/builders';
 import * as e from '../../../errors.js';
+import { extract_identifiers } from '../../../utils/ast.js';
 
 /**
  * @param {AST.DeclarationTag} node
@@ -12,6 +13,16 @@ export function DeclarationTag(node, context) {
 		e.declaration_tag_no_legacy_mode(node);
 	}
 
+	const is_top_level = context.path.length === 1 && context.path[0].type === 'Fragment';
+	if (is_top_level) {
+		const duplicate = node.declaration.declarations
+			.flatMap((declaration) => extract_identifiers(declaration.id))
+			.find((id) => context.state.analysis.instance.scope.declarations.has(id.name));
+		if (duplicate) {
+			e.declaration_duplicate(duplicate, duplicate.name);
+		}
+	}
+
 	context.visit(node.declaration, {
 		...context.state,
 		in_declaration_tag: true,
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/SnippetBlock.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/SnippetBlock.js
index c0350f8e6f..7618716ae5 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/SnippetBlock.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/SnippetBlock.js
@@ -25,19 +25,24 @@ export function SnippetBlock(node, context) {
 
 	context.next({ ...context.state, parent_element: null });
 
-	const can_hoist =
-		context.path.length === 1 &&
-		context.path[0].type === 'Fragment' &&
-		can_hoist_snippet(context.state.scope, context.state.scopes);
+	const is_top_level = context.path.length === 1 && context.path[0].type === 'Fragment';
 
-	const name = node.expression.name;
+	if (is_top_level) {
+		const name = node.expression.name;
 
-	if (can_hoist) {
-		const binding = /** @type {Binding} */ (context.state.scope.get(name));
-		context.state.analysis.module.scope.declarations.set(name, binding);
-	}
+		if (context.state.analysis.instance.scope.declarations.has(name)) {
+			e.declaration_duplicate(node.expression, name);
+		}
+
+		node.metadata.can_hoist =
+			is_top_level && can_hoist_snippet(context.state.scope, context.state.scopes);
 
-	node.metadata.can_hoist = can_hoist;
+		if (node.metadata.can_hoist) {
+			const name = node.expression.name;
+			const binding = /** @type {Binding} */ (context.state.scope.get(name));
+			context.state.analysis.module.scope.declarations.set(name, binding);
+		}
+	}
 
 	const { path } = context;
 	const parent = path.at(-2);
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-already-declared/errors.json b/packages/svelte/tests/validator/samples/declaration-tag-already-declared/errors.json
new file mode 100644
index 0000000000..723b060d19
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/declaration-tag-already-declared/errors.json
@@ -0,0 +1,14 @@
+[
+	{
+		"code": "declaration_duplicate",
+		"message": "`foo` has already been declared",
+		"start": {
+			"line": 5,
+			"column": 5
+		},
+		"end": {
+			"line": 5,
+			"column": 8
+		}
+	}
+]
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-already-declared/input.svelte b/packages/svelte/tests/validator/samples/declaration-tag-already-declared/input.svelte
new file mode 100644
index 0000000000..15372811fb
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/declaration-tag-already-declared/input.svelte
@@ -0,0 +1,5 @@
+<script>
+	let foo = 'bar';
+</script>
+
+{let foo = 'baz'}
diff --git a/packages/svelte/tests/validator/samples/snippet-already-declared/errors.json b/packages/svelte/tests/validator/samples/snippet-already-declared/errors.json
new file mode 100644
index 0000000000..bac71c2c81
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/snippet-already-declared/errors.json
@@ -0,0 +1,14 @@
+[
+	{
+		"code": "declaration_duplicate",
+		"message": "`foo` has already been declared",
+		"start": {
+			"line": 5,
+			"column": 10
+		},
+		"end": {
+			"line": 5,
+			"column": 13
+		}
+	}
+]
diff --git a/packages/svelte/tests/validator/samples/snippet-already-declared/input.svelte b/packages/svelte/tests/validator/samples/snippet-already-declared/input.svelte
new file mode 100644
index 0000000000..5745c2f8f9
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/snippet-already-declared/input.svelte
@@ -0,0 +1,5 @@
+<script>
+	let foo = 'bar';
+</script>
+
+{#snippet foo()}baz{/snippet}

From 3ef761b87b84a7aecd0e11aa4c21a41bb1c180e1 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Mon, 1 Jun 2026 18:36:01 -0400
Subject: [PATCH 073/222] Version Packages (#18346)

This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.


# Releases
## svelte@5.56.1

### Patch Changes

- fix: error at compile time on duplicate snippet/declaration tag
definitions ([#18351](https://github.com/sveltejs/svelte/pull/18351))

- fix: parse declaration tag contents more robustly
([#18353](https://github.com/sveltejs/svelte/pull/18353))

- fix: correctly transform references to earlier declarators in a
declaration tag (e.g. `{let a = $state(0), b = $derived(a * 2)}`)
([#18348](https://github.com/sveltejs/svelte/pull/18348))

- fix: avoid spurious `state_referenced_locally` warnings for `$derived`
declarations in declaration tags
([#18348](https://github.com/sveltejs/svelte/pull/18348))

- fix: tolerate whitespace before `let`/`const` in declaration tags
([#18348](https://github.com/sveltejs/svelte/pull/18348))

- fix: prevent infinite loop when a tag's expression ends with a
trailing `/` at the end of the input
([#18350](https://github.com/sveltejs/svelte/pull/18350))

- fix: more robust parsing of declaration tags with regards to `type`
([#18330](https://github.com/sveltejs/svelte/pull/18330))

- fix: preserve newlines in spread input values when the `type`
attribute is applied after `value`
([#18345](https://github.com/sveltejs/svelte/pull/18345))

- fix: update `SvelteURLSearchParams` when setting duplicate keys to the
same joined value
([#18336](https://github.com/sveltejs/svelte/pull/18336))

- fix: check references for blockers on server, too
([#18352](https://github.com/sveltejs/svelte/pull/18352))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/clever-poems-shave.md              |  5 ----
 .changeset/declaration-tag-division.md        |  5 ----
 .../declaration-tag-multiple-declarators.md   |  5 ----
 ...eclaration-tag-state-referenced-locally.md |  5 ----
 .changeset/declaration-tag-whitespace.md      |  5 ----
 ...fix-find-matching-bracket-infinite-loop.md |  5 ----
 .changeset/fix-type-identifier-in-tag.md      |  5 ----
 .changeset/input-type-before-value.md         |  5 ----
 .changeset/search-params-duplicate-set.md     |  5 ----
 .changeset/strong-cups-prove.md               |  5 ----
 packages/svelte/CHANGELOG.md                  | 24 +++++++++++++++++++
 packages/svelte/package.json                  |  2 +-
 packages/svelte/src/version.js                |  2 +-
 13 files changed, 26 insertions(+), 52 deletions(-)
 delete mode 100644 .changeset/clever-poems-shave.md
 delete mode 100644 .changeset/declaration-tag-division.md
 delete mode 100644 .changeset/declaration-tag-multiple-declarators.md
 delete mode 100644 .changeset/declaration-tag-state-referenced-locally.md
 delete mode 100644 .changeset/declaration-tag-whitespace.md
 delete mode 100644 .changeset/fix-find-matching-bracket-infinite-loop.md
 delete mode 100644 .changeset/fix-type-identifier-in-tag.md
 delete mode 100644 .changeset/input-type-before-value.md
 delete mode 100644 .changeset/search-params-duplicate-set.md
 delete mode 100644 .changeset/strong-cups-prove.md

diff --git a/.changeset/clever-poems-shave.md b/.changeset/clever-poems-shave.md
deleted file mode 100644
index 252c86b905..0000000000
--- a/.changeset/clever-poems-shave.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: error at compile time on duplicate snippet/declaration tag definitions
diff --git a/.changeset/declaration-tag-division.md b/.changeset/declaration-tag-division.md
deleted file mode 100644
index de265f0ab1..0000000000
--- a/.changeset/declaration-tag-division.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: parse declaration tag contents more robustly
diff --git a/.changeset/declaration-tag-multiple-declarators.md b/.changeset/declaration-tag-multiple-declarators.md
deleted file mode 100644
index 3f17162b54..0000000000
--- a/.changeset/declaration-tag-multiple-declarators.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: correctly transform references to earlier declarators in a declaration tag (e.g. `{let a = $state(0), b = $derived(a * 2)}`)
diff --git a/.changeset/declaration-tag-state-referenced-locally.md b/.changeset/declaration-tag-state-referenced-locally.md
deleted file mode 100644
index 00803c3e1c..0000000000
--- a/.changeset/declaration-tag-state-referenced-locally.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: avoid spurious `state_referenced_locally` warnings for `$derived` declarations in declaration tags
diff --git a/.changeset/declaration-tag-whitespace.md b/.changeset/declaration-tag-whitespace.md
deleted file mode 100644
index b64d1dd5a1..0000000000
--- a/.changeset/declaration-tag-whitespace.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: tolerate whitespace before `let`/`const` in declaration tags
diff --git a/.changeset/fix-find-matching-bracket-infinite-loop.md b/.changeset/fix-find-matching-bracket-infinite-loop.md
deleted file mode 100644
index c0656ea794..0000000000
--- a/.changeset/fix-find-matching-bracket-infinite-loop.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: prevent infinite loop when a tag's expression ends with a trailing `/` at the end of the input
diff --git a/.changeset/fix-type-identifier-in-tag.md b/.changeset/fix-type-identifier-in-tag.md
deleted file mode 100644
index 90e03da80f..0000000000
--- a/.changeset/fix-type-identifier-in-tag.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: more robust parsing of declaration tags with regards to `type`
diff --git a/.changeset/input-type-before-value.md b/.changeset/input-type-before-value.md
deleted file mode 100644
index 68d02f920f..0000000000
--- a/.changeset/input-type-before-value.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: preserve newlines in spread input values when the `type` attribute is applied after `value`
diff --git a/.changeset/search-params-duplicate-set.md b/.changeset/search-params-duplicate-set.md
deleted file mode 100644
index 9fcaa8b289..0000000000
--- a/.changeset/search-params-duplicate-set.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: update `SvelteURLSearchParams` when setting duplicate keys to the same joined value
diff --git a/.changeset/strong-cups-prove.md b/.changeset/strong-cups-prove.md
deleted file mode 100644
index ad85a1feba..0000000000
--- a/.changeset/strong-cups-prove.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: check references for blockers on server, too
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 57725580e7..a8a94bc691 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,29 @@
 # svelte
 
+## 5.56.1
+
+### Patch Changes
+
+- fix: error at compile time on duplicate snippet/declaration tag definitions ([#18351](https://github.com/sveltejs/svelte/pull/18351))
+
+- fix: parse declaration tag contents more robustly ([#18353](https://github.com/sveltejs/svelte/pull/18353))
+
+- fix: correctly transform references to earlier declarators in a declaration tag (e.g. `{let a = $state(0), b = $derived(a * 2)}`) ([#18348](https://github.com/sveltejs/svelte/pull/18348))
+
+- fix: avoid spurious `state_referenced_locally` warnings for `$derived` declarations in declaration tags ([#18348](https://github.com/sveltejs/svelte/pull/18348))
+
+- fix: tolerate whitespace before `let`/`const` in declaration tags ([#18348](https://github.com/sveltejs/svelte/pull/18348))
+
+- fix: prevent infinite loop when a tag's expression ends with a trailing `/` at the end of the input ([#18350](https://github.com/sveltejs/svelte/pull/18350))
+
+- fix: more robust parsing of declaration tags with regards to `type` ([#18330](https://github.com/sveltejs/svelte/pull/18330))
+
+- fix: preserve newlines in spread input values when the `type` attribute is applied after `value` ([#18345](https://github.com/sveltejs/svelte/pull/18345))
+
+- fix: update `SvelteURLSearchParams` when setting duplicate keys to the same joined value ([#18336](https://github.com/sveltejs/svelte/pull/18336))
+
+- fix: check references for blockers on server, too ([#18352](https://github.com/sveltejs/svelte/pull/18352))
+
 ## 5.56.0
 
 ### Minor Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 6e51dd9a93..ff2c0c4c3e 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.56.0",
+  "version": "5.56.1",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 1b080d134a..210d48461e 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.56.0';
+export const VERSION = '5.56.1';
 export const PUBLIC_VERSION = '5';

From a81f96549d6768586b6bdace0a3e5467cff114ce Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Tue, 2 Jun 2026 00:44:43 +0200
Subject: [PATCH 074/222] fix: reject pending async deriveds on discard
 (#18308)

The rejects all async deriveds of a batch as `OBSOLETE`, so they don't
hang around and bail early without triggering the batch.

If we don't do this, an async derived can trigger the already done
batch, which schedules an effect that is never flushed. Because it is
never flushed the branches it touched on its way up are never cleared,
and so anything else in that subtree is now unreactive.
---
 .changeset/warm-cougars-behave.md             |  5 +++
 .../src/internal/client/reactivity/batch.js   | 20 ++++++++--
 .../async-fork-obsolete-ignore/_config.js     | 39 +++++++++++++++++++
 .../async-fork-obsolete-ignore/main.svelte    | 23 +++++++++++
 4 files changed, 83 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/warm-cougars-behave.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-fork-obsolete-ignore/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-fork-obsolete-ignore/main.svelte

diff --git a/.changeset/warm-cougars-behave.md b/.changeset/warm-cougars-behave.md
new file mode 100644
index 0000000000..15e32f7436
--- /dev/null
+++ b/.changeset/warm-cougars-behave.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: reject pending async deriveds on discard
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 3b82059788..7d14b80519 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -41,6 +41,7 @@ import { set_signal_status } from './status.js';
 import { legacy_is_updating_store } from './store.js';
 import { invariant } from '../../shared/dev.js';
 import { log_effect_tree } from '../dev/debug.js';
+import { OBSOLETE } from './deriveds.js';
 
 /** @type {Batch | null} */
 let first_batch = null;
@@ -511,6 +512,10 @@ export class Batch {
 			if (d) deferred.promise.then(d.resolve).catch(d.reject);
 		}
 
+		// Clear them or else those that are still pending might get rejected on discard (after merged-into batch is done).
+		// This can happen when batch Y merged into X and Y has a pending boundary and therefore still-pending async deriveds inside.
+		batch.async_deriveds.clear();
+
 		// Mark is not guaranteed not touch these, so we transfer them
 		this.transfer_effects(batch.#dirty_effects, batch.#maybe_dirty_effects);
 
@@ -629,6 +634,10 @@ export class Batch {
 		for (const fn of this.#discard_callbacks) fn(this);
 		this.#discard_callbacks.clear();
 
+		for (const deferred of this.async_deriveds.values()) {
+			deferred.reject(OBSOLETE);
+		}
+
 		this.#unlink();
 		this.#deferred?.resolve();
 	}
@@ -677,12 +686,15 @@ export class Batch {
 				}
 			}
 
-			if (!batch.#started) continue;
+			var current = [...batch.current.keys()].filter(
+				(source) => !(/** @type {[any, boolean]} */ (batch.current.get(source))[1])
+			);
+
+			// If not started yet or no sources to update (which is e.g. possible for the very first batch) then bail
+			if (!batch.#started || current.length === 0) continue;
 
 			// Re-run async/block effects that depend on distinct values changed in both batches (ignoring deriveds)
-			var others = [...batch.current.keys()].filter(
-				(s) => !(/** @type {[any, boolean]} */ (batch.current.get(s))[1]) && !this.current.has(s)
-			);
+			var others = current.filter((source) => !this.current.has(source));
 
 			if (others.length === 0) {
 				if (is_earlier) {
diff --git a/packages/svelte/tests/runtime-runes/samples/async-fork-obsolete-ignore/_config.js b/packages/svelte/tests/runtime-runes/samples/async-fork-obsolete-ignore/_config.js
new file mode 100644
index 0000000000..e127fd03ec
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-fork-obsolete-ignore/_config.js
@@ -0,0 +1,39 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target, logs }) {
+		await tick();
+		const [fork, real, resolve] = target.querySelectorAll('button');
+
+		fork.click();
+		await tick();
+		resolve.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				0
+				<button>fork</button>
+				<button>real</button>
+				<button>resolve</button>
+			`
+		);
+		assert.deepEqual(logs, [0]);
+
+		real.click();
+		await tick();
+		resolve.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				1
+				<button>fork</button>
+				<button>real</button>
+				<button>resolve</button>
+			`
+		);
+		assert.deepEqual(logs, [0, 1]);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-fork-obsolete-ignore/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-fork-obsolete-ignore/main.svelte
new file mode 100644
index 0000000000..85056e02b8
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-fork-obsolete-ignore/main.svelte
@@ -0,0 +1,23 @@
+<script>
+	import { fork } from "svelte";
+
+	let count = $state(0);
+	let queued = [];
+
+	function push(v) {
+		if (!v) return v;
+
+		return new Promise((resolve) => {
+			queued.push(() => resolve(v));
+		});
+	}
+
+	$effect(() => {
+		console.log(count);
+	})
+</script>
+
+{await push(count)}
+<button onclick={() => fork(() => count++).discard()}>fork</button>
+<button onclick={() => count++}>real</button>
+<button onclick={() => queued.shift()?.()}>resolve</button>

From 85dcb91f7c890a4d6d6c23dcbcf1df23cc624272 Mon Sep 17 00:00:00 2001
From: Mathias Picker <48158184+MathiasWP@users.noreply.github.com>
Date: Tue, 2 Jun 2026 03:45:58 +0200
Subject: [PATCH 075/222] chore: upgrade to vitest v4 (#18265)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

## Summary

Bumps `vitest` and `@vitest/coverage-v8` from `^2.1.9` to `^4.1.7` (two
major versions). Three small test-harness updates compensate for vitest
4 behavior changes; all 7569 tests still pass.

- **`packages/svelte/tests/runtime-browser/test.ts`** — vitest 4 removed
the deprecated `describe(name, fn, opts)` signature. Pass options as the
second argument.
- **`packages/svelte/tests/runtime-legacy/shared.ts`** — vitest 4's
jsdom env binds `virtualConsole` to the original `globalThis.console`
reference *before* vitest wraps the console, so inline-`<script>` logs
and `jsdomError` events no longer reach per-test `console.{log,error}`
overrides. Restore vitest 2's behavior by re-routing the virtual console
through the live `console` in `beforeAll`. Also promote the window-error
listener to a named function and remove it in `finally` — previously
leaked listeners from earlier tests kept writing to module-level
`unhandled_rejection`, polluting later tests.
- **`vitest.config.js`** — bump `testTimeout` to 10s. The 5s default
trips a handful of dev-mode tests that exercise
`effect_update_depth_exceeded`, whose ~1000 Error-stack captures per
flush are slower under vitest 4's deeper async stacks.

## Test plan

- [x] `pnpm test` — 7569 passed, 63 skipped, 0 failed

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .github/workflows/ci.yml                      |   8 +-
 package.json                                  |   4 +-
 packages/svelte/package.json                  |   2 +-
 packages/svelte/tests/hydration/test.ts       |  17 +-
 packages/svelte/tests/runtime-browser/test.ts |   8 +-
 .../svelte/tests/runtime-legacy/shared.ts     |  80 +-
 packages/svelte/tests/sourcemaps/test.ts      |  16 +-
 pnpm-lock.yaml                                | 918 ++++--------------
 vitest-xhtml-environment.ts                   |   4 +-
 vitest.config.js                              |   5 +
 10 files changed, 319 insertions(+), 743 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7eff1b9fe7..365717755e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -18,12 +18,12 @@ jobs:
     strategy:
       matrix:
         include:
-          - node-version: 18
+          # Vitest 4 requires Node 20+, so tests run on 20/22/24. The published
+          # Svelte package still supports Node >=18 (see packages/svelte/package.json).
+          - node-version: 20
             os: windows-latest
-          - node-version: 18
+          - node-version: 20
             os: macOS-latest
-          - node-version: 18
-            os: ubuntu-latest
           - node-version: 20
             os: ubuntu-latest
           - node-version: 22
diff --git a/package.json b/package.json
index f741ec3e1f..0d2fbc7fd6 100644
--- a/package.json
+++ b/package.json
@@ -32,7 +32,7 @@
     "@svitejs/changesets-changelog-github-compact": "^1.1.0",
     "@types/node": "^20.11.5",
     "@types/picomatch": "^4.0.2",
-    "@vitest/coverage-v8": "^2.1.9",
+    "@vitest/coverage-v8": "^4.1.7",
     "eslint": "^10.0.0",
     "eslint-plugin-lube": "^0.5.1",
     "eslint-plugin-svelte": "^3.15.0",
@@ -44,6 +44,6 @@
     "typescript": "^5.5.4",
     "typescript-eslint": "^8.56.0",
     "v8-natives": "^1.2.5",
-    "vitest": "^2.1.9"
+    "vitest": "^4.1.7"
   }
 }
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index ff2c0c4c3e..b7e370dc7d 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -166,7 +166,7 @@
     "source-map": "^0.7.4",
     "tinyglobby": "^0.2.12",
     "typescript": "^5.5.4",
-    "vitest": "^2.1.9",
+    "vitest": "^4.1.7",
     "web-features": "^3.29.0"
   },
   "dependencies": {
diff --git a/packages/svelte/tests/hydration/test.ts b/packages/svelte/tests/hydration/test.ts
index 16e4070303..d2bf6fde34 100644
--- a/packages/svelte/tests/hydration/test.ts
+++ b/packages/svelte/tests/hydration/test.ts
@@ -25,7 +25,21 @@ interface HydrationTest extends BaseTest {
 	expect_hydration_error?: true;
 	snapshot?: (target: HTMLElement) => any;
 	test?: (
-		assert: typeof import('vitest').assert & {
+		// `_config.js` test callbacks rely on inferred parameter types, which
+		// TS treats as non-explicit and rejects for chai 5's assertion-function
+		// signatures (TS2775). Override the assertion methods we actually use
+		// with non-assertion equivalents.
+		assert: Omit<
+			typeof import('vitest').assert,
+			'ok' | 'isOk' | 'isTrue' | 'isFalse' | 'exists' | 'notExists' | 'instanceOf'
+		> & {
+			ok(value: unknown, message?: string): void;
+			isOk(value: unknown, message?: string): void;
+			isTrue(value: unknown, message?: string): void;
+			isFalse(value: unknown, message?: string): void;
+			exists(value: unknown, message?: string): void;
+			notExists(value: unknown, message?: string): void;
+			instanceOf(value: unknown, type: Function, message?: string): void;
 			htmlEqual(a: string, b: string, description?: string): void;
 		},
 		target: HTMLElement,
@@ -152,7 +166,6 @@ const { test, run } = suite<HydrationTest>(async (config, cwd) => {
 
 		if (config.test) {
 			await config.test(
-				// @ts-expect-error TS doesn't get it
 				{
 					...assert,
 					htmlEqual: assert_html_equal
diff --git a/packages/svelte/tests/runtime-browser/test.ts b/packages/svelte/tests/runtime-browser/test.ts
index 54cdc0f8be..22e8ad6489 100644
--- a/packages/svelte/tests/runtime-browser/test.ts
+++ b/packages/svelte/tests/runtime-browser/test.ts
@@ -42,9 +42,9 @@ const { run: run_browser_tests } = suite_with_variants<
 
 describe.concurrent(
 	'runtime-browser',
-	() => run_browser_tests(__dirname),
 	// Browser tests are brittle and slow on CI
-	{ timeout: 20000, retry: process.env.CI ? 1 : 0 }
+	{ timeout: 20000, retry: process.env.CI ? 1 : 0 },
+	() => run_browser_tests(__dirname)
 );
 
 const { run: run_ce_tests } = suite<ReturnType<typeof import('./assert').test>>(
@@ -55,9 +55,9 @@ const { run: run_ce_tests } = suite<ReturnType<typeof import('./assert').test>>(
 
 describe.concurrent(
 	'custom-elements',
-	() => run_ce_tests(__dirname, 'custom-elements-samples'),
 	// Browser tests are brittle and slow on CI
-	{ timeout: 20000, retry: process.env.CI ? 1 : 0 }
+	{ timeout: 20000, retry: process.env.CI ? 1 : 0 },
+	() => run_ce_tests(__dirname, 'custom-elements-samples')
 );
 
 async function run_test(
diff --git a/packages/svelte/tests/runtime-legacy/shared.ts b/packages/svelte/tests/runtime-legacy/shared.ts
index 6f30fb5d98..5c2d0dfe1c 100644
--- a/packages/svelte/tests/runtime-legacy/shared.ts
+++ b/packages/svelte/tests/runtime-legacy/shared.ts
@@ -15,19 +15,35 @@ import { clear } from '../../src/internal/client/reactivity/batch.js';
 import { hydrating } from '../../src/internal/client/dom/hydration.js';
 import { ssr_context } from '../../src/internal/server/context.js';
 
-type Assert = typeof import('vitest').assert & {
-	htmlEqual(a: string, b: string, description?: string): void;
-	htmlEqualWithOptions(
-		a: string,
-		b: string,
-		opts: {
-			preserveComments: boolean;
-			withoutNormalizeHtml: boolean;
-		},
-		description?: string
-	): void;
+// `_config.js` files call `assert.ok` etc. with `assert` typed via parameter
+// inference, which TypeScript treats as non-explicit. chai 5 (pulled in by
+// vitest 4) declares these as assertion functions (`asserts value`), so TS2775
+// fires on every call. Override the affected methods with non-assertion
+// signatures — the runtime behavior is unchanged.
+type NonAssertingMethods = {
+	ok(value: unknown, message?: string): void;
+	isOk(value: unknown, message?: string): void;
+	isTrue(value: unknown, message?: string): void;
+	isFalse(value: unknown, message?: string): void;
+	exists(value: unknown, message?: string): void;
+	notExists(value: unknown, message?: string): void;
+	instanceOf(value: unknown, type: Function, message?: string): void;
 };
 
+type Assert = Omit<typeof import('vitest').assert, keyof NonAssertingMethods> &
+	NonAssertingMethods & {
+		htmlEqual(a: string, b: string, description?: string): void;
+		htmlEqualWithOptions(
+			a: string,
+			b: string,
+			opts: {
+				preserveComments: boolean;
+				withoutNormalizeHtml: boolean;
+			},
+			description?: string
+		): void;
+	};
+
 // TODO remove this shim when we can
 // @ts-expect-error
 Promise.withResolvers = () => {
@@ -75,6 +91,7 @@ export interface RuntimeTest<Props extends Record<string, any> = Record<string,
 		raf: {
 			tick: (ms: number) => void;
 		};
+		snapshot: any;
 		target: HTMLElement;
 		window: Window & {
 			Event: typeof Event;
@@ -126,6 +143,16 @@ const listeners = process.rawListeners('unhandledRejection');
 beforeAll(() => {
 	// @ts-expect-error TODO huh?
 	process.prependListener('unhandledRejection', unhandled_rejection_handler);
+
+	// Route inline-`<script>` console calls through `globalThis.console` at
+	// call time, so per-test `console.{log,warn,error}` overrides see them.
+	// (jsdom scripts run in a VM with their own `console` object, separate
+	// from Node's `globalThis.console` — vitest 4's jsdom env no longer
+	// bridges them per-test.)
+	const vc = (window as any)._virtualConsole;
+	for (const m of ['log', 'warn', 'error'] as const) {
+		vc?.on(m, (...args: any[]) => console[m](...args));
+	}
 });
 
 beforeEach(() => {
@@ -255,6 +282,26 @@ async function run_test_variant(
 	let warnings: string[] = [];
 	let errors: string[] = [];
 	let manual_hydrate = false;
+	let intercept_errors = false;
+
+	// Capture phase so we still see the error if a test installs its own
+	// `stopImmediatePropagation` listener (e.g. event-handler-*). Named so we
+	// can remove it in `finally` — otherwise listeners from earlier tests leak
+	// and keep writing to module-level `unhandled_rejection`. When the test
+	// intercepts `errors`, mirror jsdom's `Uncaught [...]` format into the
+	// array — vitest 4's jsdom env no longer routes `jsdomError` to vitest's
+	// wrapped console reliably (works locally but not in CI's forks pool).
+	const window_error_listener = (e: ErrorEvent) => {
+		if (intercept_errors) {
+			const detail = e.error;
+			const is_error = detail && detail.name && detail.message !== undefined && detail.stack;
+			const error_string = is_error ? `[${detail.name}: ${detail.message}]` : String(detail);
+			errors.push(`Error: Uncaught ${error_string}\n${detail?.stack ?? ''}`, detail);
+		} else {
+			unhandled_rejection = e.error;
+		}
+		e.preventDefault();
+	};
 
 	{
 		// use some crude static analysis to determine if logs/warnings are intercepted.
@@ -317,6 +364,7 @@ async function run_test_variant(
 		}
 
 		if (str.slice(0, i).includes('errors') || config.errors) {
+			intercept_errors = true;
 			// eslint-disable-next-line no-console
 			console.error = (...args) => {
 				errors.push(...args);
@@ -348,10 +396,7 @@ async function run_test_variant(
 		window.document.head.innerHTML = styles ? `<style>${styles}</style>` : '';
 		window.document.body.innerHTML = '<main></main>';
 
-		window.addEventListener('error', (e) => {
-			unhandled_rejection = e.error;
-			e.preventDefault();
-		});
+		window.addEventListener('error', window_error_listener, true);
 
 		globalThis.requestAnimationFrame = globalThis.setTimeout;
 
@@ -423,7 +468,6 @@ async function run_test_variant(
 				await config.test_ssr({
 					logs,
 					warnings,
-					// @ts-expect-error
 					assert: {
 						...assert,
 						htmlEqual: assert_html_equal,
@@ -515,7 +559,6 @@ async function run_test_variant(
 					}
 
 					await config.test({
-						// @ts-expect-error TS doesn't get it
 						assert: {
 							...assert,
 							htmlEqual: assert_html_equal,
@@ -525,6 +568,7 @@ async function run_test_variant(
 						component: runes ? props : instance,
 						instance,
 						mod,
+						ok,
 						target,
 						snapshot,
 						window,
@@ -593,6 +637,8 @@ async function run_test_variant(
 			throw new Error('Hydration state was not cleared');
 		}
 
+		window.removeEventListener('error', window_error_listener, true);
+
 		config.after_test?.();
 
 		// Free up the microtask queue
diff --git a/packages/svelte/tests/sourcemaps/test.ts b/packages/svelte/tests/sourcemaps/test.ts
index 6749483079..b9d0e5abdc 100644
--- a/packages/svelte/tests/sourcemaps/test.ts
+++ b/packages/svelte/tests/sourcemaps/test.ts
@@ -31,7 +31,21 @@ interface SourcemapTest extends BaseTest {
 	/** The expected `sources` array in the source map */
 	css_map_sources?: string[];
 	test?: (obj: {
-		assert: typeof assert;
+		// chai 5's `asserts value` signatures trip TS2775 in `_config.js` files
+		// where `assert` is a destructured parameter (non-explicit). Override
+		// the assertion methods we use with non-assertion equivalents.
+		assert: Omit<
+			typeof assert,
+			'ok' | 'isOk' | 'isTrue' | 'isFalse' | 'exists' | 'notExists' | 'instanceOf'
+		> & {
+			ok(value: unknown, message?: string): void;
+			isOk(value: unknown, message?: string): void;
+			isTrue(value: unknown, message?: string): void;
+			isFalse(value: unknown, message?: string): void;
+			exists(value: unknown, message?: string): void;
+			notExists(value: unknown, message?: string): void;
+			instanceOf(value: unknown, type: Function, message?: string): void;
+		};
 		input: string;
 		map_preprocessed: any;
 		code_preprocessed: string;
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 767af0515a..a970a9cf6a 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -27,8 +27,8 @@ importers:
         specifier: ^4.0.2
         version: 4.0.2
       '@vitest/coverage-v8':
-        specifier: ^2.1.9
-        version: 2.1.9(vitest@2.1.9(@types/node@20.19.17)(jsdom@25.0.1)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+        specifier: ^4.1.7
+        version: 4.1.7(vitest@4.1.7)
       eslint:
         specifier: ^10.0.0
         version: 10.0.0
@@ -63,8 +63,8 @@ importers:
         specifier: ^1.2.5
         version: 1.2.5
       vitest:
-        specifier: ^2.1.9
-        version: 2.1.9(@types/node@20.19.17)(jsdom@25.0.1)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+        specifier: ^4.1.7
+        version: 4.1.7(@types/node@20.19.17)(@vitest/coverage-v8@4.1.7)(jsdom@25.0.1)(vite@7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
 
   packages/svelte:
     dependencies:
@@ -163,8 +163,8 @@ importers:
         specifier: ^5.5.4
         version: 5.5.4
       vitest:
-        specifier: ^2.1.9
-        version: 2.1.9(@types/node@20.19.17)(jsdom@25.0.1)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+        specifier: ^4.1.7
+        version: 4.1.7(@types/node@20.19.17)(@vitest/coverage-v8@4.1.7)(jsdom@25.0.1)(vite@7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
       web-features:
         specifier: ^3.29.0
         version: 3.29.0
@@ -202,20 +202,16 @@ packages:
     resolution: {integrity: sha512-1Yjs2SvM8TflER/OD3cOjhWWOZb58A2t7wpE2S9XfBYTiIl+XFhQG2bjy4Pu1I+EAlCNUzRDYDdFwFYUKvXcIA==}
     engines: {node: '>=0.10.0'}
 
-  '@ampproject/remapping@2.3.0':
-    resolution: {integrity: sha512-30iZtAPgz+LTIYoeivqYo853f02jBYSd5uGnGpkFV0M3xOt9aN73erkgYAmZU43x4VfqcnLxW9Kpg3R5LC4YYw==}
-    engines: {node: '>=6.0.0'}
-
-  '@babel/helper-string-parser@7.24.8':
-    resolution: {integrity: sha512-pO9KhhRcuUyGnJWwyEgnRJTSIZHiT+vMD0kPeD+so0l7mxkMT19g3pjY9GTnHySck/hDzq+dtW/4VgnMkippsQ==}
+  '@babel/helper-string-parser@7.27.1':
+    resolution: {integrity: sha512-qMlSxKbpRlAridDExk92nSobyDdpPijUq2DW6oDnUqd0iOGxmQjyqhMIihI9+zv4LPyZdRje2cavWPbCbWm3eA==}
     engines: {node: '>=6.9.0'}
 
-  '@babel/helper-validator-identifier@7.24.7':
-    resolution: {integrity: sha512-rR+PBcQ1SMQDDyF6X0wxtG8QyLCgUB0eRAGguqRLfkCA87l7yAP7ehq8SNj96OOGTO8OBV70KhuFYcIkHXOg0w==}
+  '@babel/helper-validator-identifier@7.28.5':
+    resolution: {integrity: sha512-qSs4ifwzKJSV39ucNjsvc6WVHs6b7S03sOh2OcHF9UHfVPqWWALUsNUVzhSBiItjRZoLHx7nIarVjqKVusUZ1Q==}
     engines: {node: '>=6.9.0'}
 
-  '@babel/parser@7.25.4':
-    resolution: {integrity: sha512-nq+eWrOgdtu3jG5Os4TQP3x3cLA8hR8TvJNjD8vnPa20WGycimcparWnLK4jJhElTK6SDyuJo1weMKO/5LpmLA==}
+  '@babel/parser@7.29.3':
+    resolution: {integrity: sha512-b3ctpQwp+PROvU/cttc4OYl4MzfJUWy6FZg+PMXfzmt/+39iHVF0sDfqay8TQM3JA2EUOyKcFZt75jWriQijsA==}
     engines: {node: '>=6.0.0'}
     hasBin: true
 
@@ -223,12 +219,13 @@ packages:
     resolution: {integrity: sha512-Q/N6JNWvIvPnLDvjlE1OUBLPQHH6l3CltCEsHIujp45zQUSSh8K+gHnaEX45yAT1nyngnINhvWtzN+Nb9D8RAQ==}
     engines: {node: '>=6.9.0'}
 
-  '@babel/types@7.25.4':
-    resolution: {integrity: sha512-zQ1ijeeCXVEh+aNL0RlmkPkG8HUiDcU2pzQQFjtbntgAczRASFzj4H+6+bV+dy1ntKR14I/DypeuRG1uma98iQ==}
+  '@babel/types@7.29.0':
+    resolution: {integrity: sha512-LwdZHpScM4Qz8Xw2iKSzS+cfglZzJGvofQICy7W7v4caru4EaAmyUuO6BGrbyQ2mYV11W0U8j5mBhd14dd3B0A==}
     engines: {node: '>=6.9.0'}
 
-  '@bcoe/v8-coverage@0.2.3':
-    resolution: {integrity: sha512-0hYQ8SB4Db5zvZB4axdMHGwEaQjkZzFjQiN9LVYvIFB2nSUHW9tYpxWriPrWDASIxiaXax83REcLxuSdnGPZtw==}
+  '@bcoe/v8-coverage@1.0.2':
+    resolution: {integrity: sha512-6zABk/ECA/QYSCQ1NGiVwwbQerUCZ+TQbp64Q3AgmfNvurHH0j8TtXa1qbShXA6qqkpAj4V5W8pP6mLe1mcMqA==}
+    engines: {node: '>=18'}
 
   '@changesets/apply-release-plan@7.0.14':
     resolution: {integrity: sha512-ddBvf9PHdy2YY0OUiEl3TV78mH9sckndJR14QAt87KLEbIov81XO0q0QAmvooBxXlqRRP8I9B7XOzZwQG7JkWA==}
@@ -288,12 +285,6 @@ packages:
   '@changesets/write@0.4.0':
     resolution: {integrity: sha512-CdTLvIOPiCNuH71pyDu3rA+Q0n65cmAbXnwWH84rKGiFumFzkmHNT8KHTMEchcxN+Kl8I54xGUhJ7l3E7X396Q==}
 
-  '@esbuild/aix-ppc64@0.21.5':
-    resolution: {integrity: sha512-1SDgH6ZSPTlggy1yI6+Dbkiz8xzpHJEVAlF/AM1tHPLsf5STom9rwtjE4hKAF20FfXXNTFqEYXyJNWh1GiZedQ==}
-    engines: {node: '>=12'}
-    cpu: [ppc64]
-    os: [aix]
-
   '@esbuild/aix-ppc64@0.25.11':
     resolution: {integrity: sha512-Xt1dOL13m8u0WE8iplx9Ibbm+hFAO0GsU2P34UNoDGvZYkY8ifSiy6Zuc1lYxfG7svWE2fzqCUmFp5HCn51gJg==}
     engines: {node: '>=18'}
@@ -306,12 +297,6 @@ packages:
     cpu: [ppc64]
     os: [aix]
 
-  '@esbuild/android-arm64@0.21.5':
-    resolution: {integrity: sha512-c0uX9VAUBQ7dTDCjq+wdyGLowMdtR/GoC2U5IYk/7D1H1JYC0qseD7+11iMP2mRLN9RcCMRcjC4YMclCzGwS/A==}
-    engines: {node: '>=12'}
-    cpu: [arm64]
-    os: [android]
-
   '@esbuild/android-arm64@0.25.11':
     resolution: {integrity: sha512-9slpyFBc4FPPz48+f6jyiXOx/Y4v34TUeDDXJpZqAWQn/08lKGeD8aDp9TMn9jDz2CiEuHwfhRmGBvpnd/PWIQ==}
     engines: {node: '>=18'}
@@ -324,12 +309,6 @@ packages:
     cpu: [arm64]
     os: [android]
 
-  '@esbuild/android-arm@0.21.5':
-    resolution: {integrity: sha512-vCPvzSjpPHEi1siZdlvAlsPxXl7WbOVUBBAowWug4rJHb68Ox8KualB+1ocNvT5fjv6wpkX6o/iEpbDrf68zcg==}
-    engines: {node: '>=12'}
-    cpu: [arm]
-    os: [android]
-
   '@esbuild/android-arm@0.25.11':
     resolution: {integrity: sha512-uoa7dU+Dt3HYsethkJ1k6Z9YdcHjTrSb5NUy66ZfZaSV8hEYGD5ZHbEMXnqLFlbBflLsl89Zke7CAdDJ4JI+Gg==}
     engines: {node: '>=18'}
@@ -342,12 +321,6 @@ packages:
     cpu: [arm]
     os: [android]
 
-  '@esbuild/android-x64@0.21.5':
-    resolution: {integrity: sha512-D7aPRUUNHRBwHxzxRvp856rjUHRFW1SdQATKXH2hqA0kAZb1hKmi02OpYRacl0TxIGz/ZmXWlbZgjwWYaCakTA==}
-    engines: {node: '>=12'}
-    cpu: [x64]
-    os: [android]
-
   '@esbuild/android-x64@0.25.11':
     resolution: {integrity: sha512-Sgiab4xBjPU1QoPEIqS3Xx+R2lezu0LKIEcYe6pftr56PqPygbB7+szVnzoShbx64MUupqoE0KyRlN7gezbl8g==}
     engines: {node: '>=18'}
@@ -360,12 +333,6 @@ packages:
     cpu: [x64]
     os: [android]
 
-  '@esbuild/darwin-arm64@0.21.5':
-    resolution: {integrity: sha512-DwqXqZyuk5AiWWf3UfLiRDJ5EDd49zg6O9wclZ7kUMv2WRFr4HKjXp/5t8JZ11QbQfUS6/cRCKGwYhtNAY88kQ==}
-    engines: {node: '>=12'}
-    cpu: [arm64]
-    os: [darwin]
-
   '@esbuild/darwin-arm64@0.25.11':
     resolution: {integrity: sha512-VekY0PBCukppoQrycFxUqkCojnTQhdec0vevUL/EDOCnXd9LKWqD/bHwMPzigIJXPhC59Vd1WFIL57SKs2mg4w==}
     engines: {node: '>=18'}
@@ -378,12 +345,6 @@ packages:
     cpu: [arm64]
     os: [darwin]
 
-  '@esbuild/darwin-x64@0.21.5':
-    resolution: {integrity: sha512-se/JjF8NlmKVG4kNIuyWMV/22ZaerB+qaSi5MdrXtd6R08kvs2qCN4C09miupktDitvh8jRFflwGFBQcxZRjbw==}
-    engines: {node: '>=12'}
-    cpu: [x64]
-    os: [darwin]
-
   '@esbuild/darwin-x64@0.25.11':
     resolution: {integrity: sha512-+hfp3yfBalNEpTGp9loYgbknjR695HkqtY3d3/JjSRUyPg/xd6q+mQqIb5qdywnDxRZykIHs3axEqU6l1+oWEQ==}
     engines: {node: '>=18'}
@@ -396,12 +357,6 @@ packages:
     cpu: [x64]
     os: [darwin]
 
-  '@esbuild/freebsd-arm64@0.21.5':
-    resolution: {integrity: sha512-5JcRxxRDUJLX8JXp/wcBCy3pENnCgBR9bN6JsY4OmhfUtIHe3ZW0mawA7+RDAcMLrMIZaf03NlQiX9DGyB8h4g==}
-    engines: {node: '>=12'}
-    cpu: [arm64]
-    os: [freebsd]
-
   '@esbuild/freebsd-arm64@0.25.11':
     resolution: {integrity: sha512-CmKjrnayyTJF2eVuO//uSjl/K3KsMIeYeyN7FyDBjsR3lnSJHaXlVoAK8DZa7lXWChbuOk7NjAc7ygAwrnPBhA==}
     engines: {node: '>=18'}
@@ -414,12 +369,6 @@ packages:
     cpu: [arm64]
     os: [freebsd]
 
-  '@esbuild/freebsd-x64@0.21.5':
-    resolution: {integrity: sha512-J95kNBj1zkbMXtHVH29bBriQygMXqoVQOQYA+ISs0/2l3T9/kj42ow2mpqerRBxDJnmkUDCaQT/dfNXWX/ZZCQ==}
-    engines: {node: '>=12'}
-    cpu: [x64]
-    os: [freebsd]
-
   '@esbuild/freebsd-x64@0.25.11':
     resolution: {integrity: sha512-Dyq+5oscTJvMaYPvW3x3FLpi2+gSZTCE/1ffdwuM6G1ARang/mb3jvjxs0mw6n3Lsw84ocfo9CrNMqc5lTfGOw==}
     engines: {node: '>=18'}
@@ -432,12 +381,6 @@ packages:
     cpu: [x64]
     os: [freebsd]
 
-  '@esbuild/linux-arm64@0.21.5':
-    resolution: {integrity: sha512-ibKvmyYzKsBeX8d8I7MH/TMfWDXBF3db4qM6sy+7re0YXya+K1cem3on9XgdT2EQGMu4hQyZhan7TeQ8XkGp4Q==}
-    engines: {node: '>=12'}
-    cpu: [arm64]
-    os: [linux]
-
   '@esbuild/linux-arm64@0.25.11':
     resolution: {integrity: sha512-Qr8AzcplUhGvdyUF08A1kHU3Vr2O88xxP0Tm8GcdVOUm25XYcMPp2YqSVHbLuXzYQMf9Bh/iKx7YPqECs6ffLA==}
     engines: {node: '>=18'}
@@ -450,12 +393,6 @@ packages:
     cpu: [arm64]
     os: [linux]
 
-  '@esbuild/linux-arm@0.21.5':
-    resolution: {integrity: sha512-bPb5AHZtbeNGjCKVZ9UGqGwo8EUu4cLq68E95A53KlxAPRmUyYv2D6F0uUI65XisGOL1hBP5mTronbgo+0bFcA==}
-    engines: {node: '>=12'}
-    cpu: [arm]
-    os: [linux]
-
   '@esbuild/linux-arm@0.25.11':
     resolution: {integrity: sha512-TBMv6B4kCfrGJ8cUPo7vd6NECZH/8hPpBHHlYI3qzoYFvWu2AdTvZNuU/7hsbKWqu/COU7NIK12dHAAqBLLXgw==}
     engines: {node: '>=18'}
@@ -468,12 +405,6 @@ packages:
     cpu: [arm]
     os: [linux]
 
-  '@esbuild/linux-ia32@0.21.5':
-    resolution: {integrity: sha512-YvjXDqLRqPDl2dvRODYmmhz4rPeVKYvppfGYKSNGdyZkA01046pLWyRKKI3ax8fbJoK5QbxblURkwK/MWY18Tg==}
-    engines: {node: '>=12'}
-    cpu: [ia32]
-    os: [linux]
-
   '@esbuild/linux-ia32@0.25.11':
     resolution: {integrity: sha512-TmnJg8BMGPehs5JKrCLqyWTVAvielc615jbkOirATQvWWB1NMXY77oLMzsUjRLa0+ngecEmDGqt5jiDC6bfvOw==}
     engines: {node: '>=18'}
@@ -486,12 +417,6 @@ packages:
     cpu: [ia32]
     os: [linux]
 
-  '@esbuild/linux-loong64@0.21.5':
-    resolution: {integrity: sha512-uHf1BmMG8qEvzdrzAqg2SIG/02+4/DHB6a9Kbya0XDvwDEKCoC8ZRWI5JJvNdUjtciBGFQ5PuBlpEOXQj+JQSg==}
-    engines: {node: '>=12'}
-    cpu: [loong64]
-    os: [linux]
-
   '@esbuild/linux-loong64@0.25.11':
     resolution: {integrity: sha512-DIGXL2+gvDaXlaq8xruNXUJdT5tF+SBbJQKbWy/0J7OhU8gOHOzKmGIlfTTl6nHaCOoipxQbuJi7O++ldrxgMw==}
     engines: {node: '>=18'}
@@ -504,12 +429,6 @@ packages:
     cpu: [loong64]
     os: [linux]
 
-  '@esbuild/linux-mips64el@0.21.5':
-    resolution: {integrity: sha512-IajOmO+KJK23bj52dFSNCMsz1QP1DqM6cwLUv3W1QwyxkyIWecfafnI555fvSGqEKwjMXVLokcV5ygHW5b3Jbg==}
-    engines: {node: '>=12'}
-    cpu: [mips64el]
-    os: [linux]
-
   '@esbuild/linux-mips64el@0.25.11':
     resolution: {integrity: sha512-Osx1nALUJu4pU43o9OyjSCXokFkFbyzjXb6VhGIJZQ5JZi8ylCQ9/LFagolPsHtgw6himDSyb5ETSfmp4rpiKQ==}
     engines: {node: '>=18'}
@@ -522,12 +441,6 @@ packages:
     cpu: [mips64el]
     os: [linux]
 
-  '@esbuild/linux-ppc64@0.21.5':
-    resolution: {integrity: sha512-1hHV/Z4OEfMwpLO8rp7CvlhBDnjsC3CttJXIhBi+5Aj5r+MBvy4egg7wCbe//hSsT+RvDAG7s81tAvpL2XAE4w==}
-    engines: {node: '>=12'}
-    cpu: [ppc64]
-    os: [linux]
-
   '@esbuild/linux-ppc64@0.25.11':
     resolution: {integrity: sha512-nbLFgsQQEsBa8XSgSTSlrnBSrpoWh7ioFDUmwo158gIm5NNP+17IYmNWzaIzWmgCxq56vfr34xGkOcZ7jX6CPw==}
     engines: {node: '>=18'}
@@ -540,12 +453,6 @@ packages:
     cpu: [ppc64]
     os: [linux]
 
-  '@esbuild/linux-riscv64@0.21.5':
-    resolution: {integrity: sha512-2HdXDMd9GMgTGrPWnJzP2ALSokE/0O5HhTUvWIbD3YdjME8JwvSCnNGBnTThKGEB91OZhzrJ4qIIxk/SBmyDDA==}
-    engines: {node: '>=12'}
-    cpu: [riscv64]
-    os: [linux]
-
   '@esbuild/linux-riscv64@0.25.11':
     resolution: {integrity: sha512-HfyAmqZi9uBAbgKYP1yGuI7tSREXwIb438q0nqvlpxAOs3XnZ8RsisRfmVsgV486NdjD7Mw2UrFSw51lzUk1ww==}
     engines: {node: '>=18'}
@@ -558,12 +465,6 @@ packages:
     cpu: [riscv64]
     os: [linux]
 
-  '@esbuild/linux-s390x@0.21.5':
-    resolution: {integrity: sha512-zus5sxzqBJD3eXxwvjN1yQkRepANgxE9lgOW2qLnmr8ikMTphkjgXu1HR01K4FJg8h1kEEDAqDcZQtbrRnB41A==}
-    engines: {node: '>=12'}
-    cpu: [s390x]
-    os: [linux]
-
   '@esbuild/linux-s390x@0.25.11':
     resolution: {integrity: sha512-HjLqVgSSYnVXRisyfmzsH6mXqyvj0SA7pG5g+9W7ESgwA70AXYNpfKBqh1KbTxmQVaYxpzA/SvlB9oclGPbApw==}
     engines: {node: '>=18'}
@@ -576,12 +477,6 @@ packages:
     cpu: [s390x]
     os: [linux]
 
-  '@esbuild/linux-x64@0.21.5':
-    resolution: {integrity: sha512-1rYdTpyv03iycF1+BhzrzQJCdOuAOtaqHTWJZCWvijKD2N5Xu0TtVC8/+1faWqcP9iBCWOmjmhoH94dH82BxPQ==}
-    engines: {node: '>=12'}
-    cpu: [x64]
-    os: [linux]
-
   '@esbuild/linux-x64@0.25.11':
     resolution: {integrity: sha512-HSFAT4+WYjIhrHxKBwGmOOSpphjYkcswF449j6EjsjbinTZbp8PJtjsVK1XFJStdzXdy/jaddAep2FGY+wyFAQ==}
     engines: {node: '>=18'}
@@ -606,12 +501,6 @@ packages:
     cpu: [arm64]
     os: [netbsd]
 
-  '@esbuild/netbsd-x64@0.21.5':
-    resolution: {integrity: sha512-Woi2MXzXjMULccIwMnLciyZH4nCIMpWQAs049KEeMvOcNADVxo0UBIQPfSmxB3CWKedngg7sWZdLvLczpe0tLg==}
-    engines: {node: '>=12'}
-    cpu: [x64]
-    os: [netbsd]
-
   '@esbuild/netbsd-x64@0.25.11':
     resolution: {integrity: sha512-u7tKA+qbzBydyj0vgpu+5h5AeudxOAGncb8N6C9Kh1N4n7wU1Xw1JDApsRjpShRpXRQlJLb9wY28ELpwdPcZ7A==}
     engines: {node: '>=18'}
@@ -636,12 +525,6 @@ packages:
     cpu: [arm64]
     os: [openbsd]
 
-  '@esbuild/openbsd-x64@0.21.5':
-    resolution: {integrity: sha512-HLNNw99xsvx12lFBUwoT8EVCsSvRNDVxNpjZ7bPn947b8gJPzeHWyNVhFsaerc0n3TsbOINvRP2byTZ5LKezow==}
-    engines: {node: '>=12'}
-    cpu: [x64]
-    os: [openbsd]
-
   '@esbuild/openbsd-x64@0.25.11':
     resolution: {integrity: sha512-CN+7c++kkbrckTOz5hrehxWN7uIhFFlmS/hqziSFVWpAzpWrQoAG4chH+nN3Be+Kzv/uuo7zhX716x3Sn2Jduw==}
     engines: {node: '>=18'}
@@ -666,12 +549,6 @@ packages:
     cpu: [arm64]
     os: [openharmony]
 
-  '@esbuild/sunos-x64@0.21.5':
-    resolution: {integrity: sha512-6+gjmFpfy0BHU5Tpptkuh8+uw3mnrvgs+dSPQXQOv3ekbordwnzTVEb4qnIvQcYXq6gzkyTnoZ9dZG+D4garKg==}
-    engines: {node: '>=12'}
-    cpu: [x64]
-    os: [sunos]
-
   '@esbuild/sunos-x64@0.25.11':
     resolution: {integrity: sha512-nq2xdYaWxyg9DcIyXkZhcYulC6pQ2FuCgem3LI92IwMgIZ69KHeY8T4Y88pcwoLIjbed8n36CyKoYRDygNSGhA==}
     engines: {node: '>=18'}
@@ -684,12 +561,6 @@ packages:
     cpu: [x64]
     os: [sunos]
 
-  '@esbuild/win32-arm64@0.21.5':
-    resolution: {integrity: sha512-Z0gOTd75VvXqyq7nsl93zwahcTROgqvuAcYDUr+vOv8uHhNSKROyU961kgtCD1e95IqPKSQKH7tBTslnS3tA8A==}
-    engines: {node: '>=12'}
-    cpu: [arm64]
-    os: [win32]
-
   '@esbuild/win32-arm64@0.25.11':
     resolution: {integrity: sha512-3XxECOWJq1qMZ3MN8srCJ/QfoLpL+VaxD/WfNRm1O3B4+AZ/BnLVgFbUV3eiRYDMXetciH16dwPbbHqwe1uU0Q==}
     engines: {node: '>=18'}
@@ -702,12 +573,6 @@ packages:
     cpu: [arm64]
     os: [win32]
 
-  '@esbuild/win32-ia32@0.21.5':
-    resolution: {integrity: sha512-SWXFF1CL2RVNMaVs+BBClwtfZSvDgtL//G/smwAc5oVK/UPu2Gu9tIaRgFmYFFKrmg3SyAjSrElf0TiJ1v8fYA==}
-    engines: {node: '>=12'}
-    cpu: [ia32]
-    os: [win32]
-
   '@esbuild/win32-ia32@0.25.11':
     resolution: {integrity: sha512-3ukss6gb9XZ8TlRyJlgLn17ecsK4NSQTmdIXRASVsiS2sQ6zPPZklNJT5GR5tE/MUarymmy8kCEf5xPCNCqVOA==}
     engines: {node: '>=18'}
@@ -720,12 +585,6 @@ packages:
     cpu: [ia32]
     os: [win32]
 
-  '@esbuild/win32-x64@0.21.5':
-    resolution: {integrity: sha512-tQd/1efJuzPC6rCFwEvLtci/xNFcTZknmXs98FYDfGE4wP9ClFV98nyKrzJKVPMhdDnjzLhdUyMX4PsQAPjwIw==}
-    engines: {node: '>=12'}
-    cpu: [x64]
-    os: [win32]
-
   '@esbuild/win32-x64@0.25.11':
     resolution: {integrity: sha512-D7Hpz6A2L4hzsRpPaCYkQnGOotdUpDzSGRIv9I+1ITdHROSFUWW95ZPZWQmGka1Fg7W3zFJowyn9WGwMJ0+KPA==}
     engines: {node: '>=18'}
@@ -810,14 +669,6 @@ packages:
     resolution: {integrity: sha512-WMz71T1JS624nWj2n2fnYAuPovhv7EUhk69R6i9dsVyzxt5eM3bjwvgk9L+APE1TRscGysAVMANkB0jh0LQZrQ==}
     engines: {node: 20 || >=22}
 
-  '@isaacs/cliui@8.0.2':
-    resolution: {integrity: sha512-O8jcjabXaleOG9DQ0+ARXWZBTfnP4WNAqzuiJK7ll44AmxGKv/J2M4TPjxjY3znBCfvBXFzucm1twdyFybFqEA==}
-    engines: {node: '>=12'}
-
-  '@istanbuljs/schema@0.1.3':
-    resolution: {integrity: sha512-ZXRY4jNvVgSVQ8DL3LTcakaAtXwTVUxE81hslsyD2AtoXW/wVob10HkOJ1X/pAlcI7D+2YoZKg5do8G/w6RYgA==}
-    engines: {node: '>=8'}
-
   '@jridgewell/gen-mapping@0.3.5':
     resolution: {integrity: sha512-IzL8ZoEDIBRWEzlCcRhOaCupYyN5gdIK+Q6fbFdPDg6HqX6jpkItn7DFIpW9LQzXG6Df9sA7+OKnq0qlz/GaQg==}
     engines: {node: '>=6.0.0'}
@@ -839,6 +690,9 @@ packages:
   '@jridgewell/sourcemap-codec@1.5.0':
     resolution: {integrity: sha512-gv3ZRaISU3fjPAgNsriBRqGWQL6quFx04YMPW/zD8XMLsU32mhCCbfbO6KZFLjvYpCZ8zyDEgqsgf+PwPaM7GQ==}
 
+  '@jridgewell/sourcemap-codec@1.5.5':
+    resolution: {integrity: sha512-cYQ9310grqxueWbl+WuIUIaiUaDcj7WOq5fVhEljNVgRfOUhY9fy2zTvfoqWsnebh8Sl70VScFbICvJnLKB0Og==}
+
   '@jridgewell/trace-mapping@0.3.31':
     resolution: {integrity: sha512-zzNR+SdQSDJzc8joaeP8QQoCQr8NuYx2dIIytl1QeBEZHJ9uW6hebsrYgbz8hJwUQao3TWCMtmfV8Nu1twOLAw==}
 
@@ -860,10 +714,6 @@ packages:
     resolution: {integrity: sha512-oGB+UxlgWcgQkgwo8GcEGwemoTFt3FIO9ababBmaGwXIoBKZ+GTy0pP185beGg7Llih/NSHSV2XAs1lnznocSg==}
     engines: {node: '>= 8'}
 
-  '@pkgjs/parseargs@0.11.0':
-    resolution: {integrity: sha512-+1VkjdD0QBLPodGrJUeqarH8VAIvQODIbwh9XpP5Syisf7YoQgsJKPNFoqqLQlu+VQ/tVSshMR6loPMn8U+dPg==}
-    engines: {node: '>=14'}
-
   '@playwright/test@1.60.0':
     resolution: {integrity: sha512-O71yZIbAh/PxDMNGns37GHBIfrVkEVyn+AXyIa5dOTfb4/xNvRWV+Vv/NMbNCtODB/pO7vLlF2OTmMVLhmr7Ag==}
     engines: {node: '>=18'}
@@ -1042,6 +892,9 @@ packages:
     cpu: [x64]
     os: [win32]
 
+  '@standard-schema/spec@1.1.0':
+    resolution: {integrity: sha512-l2aFy5jALhniG5HgqrD6jXLi/rUWrKvqN/qJx6yoJsgKhblVd+iqqU4RCXavm/jPityDo5TCvKMnpjKnOriy0w==}
+
   '@stylistic/eslint-plugin-js@1.8.0':
     resolution: {integrity: sha512-jdvnzt+pZPg8TfclZlTZPiUbbima93ylvQ+wNgHLNmup3obY6heQvgewSu9i2CfS61BnRByv+F9fxQLPoNeHag==}
     engines: {node: ^16.0.0 || >=18.0.0}
@@ -1087,6 +940,12 @@ packages:
   '@types/aria-query@5.0.4':
     resolution: {integrity: sha512-rfT93uj5s0PRL7EzccGMs3brplhcrghnDoV26NqKhCAS1hVo+WdNsPvE/yb6ilfr5hi2MEk6d5EWJTKdxg8jVw==}
 
+  '@types/chai@5.2.3':
+    resolution: {integrity: sha512-Mw558oeA9fFbv65/y4mHtXDs9bPnFMZAL/jxdPFUpOHHIXX91mcgEHbS5Lahr+pwZFR8A7GQleRWeI6cGFC2UA==}
+
+  '@types/deep-eql@4.0.2':
+    resolution: {integrity: sha512-c9h9dVVMigMPc4bwTvC5dxqtqJZwQPePsWjPlpSOnojbor6pGqdk541lfA7AqFQr5pB1BRdq0juY9db81BwyFw==}
+
   '@types/eslint@8.56.12':
     resolution: {integrity: sha512-03ruubjWyOHlmljCVoxSuNDdmfZDzsrrz0P2LeJsOXr+ZwFQ+0yQIwNCwt/GYhV7Z31fgtXJTAEs+FYlEL851g==}
 
@@ -1183,43 +1042,43 @@ packages:
     resolution: {integrity: sha512-q+SL+b+05Ud6LbEE35qe4A99P+htKTKVbyiNEe45eCbJFyh/HVK9QXwlrbz+Q4L8SOW4roxSVwXYj4DMBT7Ieg==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
 
-  '@vitest/coverage-v8@2.1.9':
-    resolution: {integrity: sha512-Z2cOr0ksM00MpEfyVE8KXIYPEcBFxdbLSs56L8PO0QQMxt/6bDj45uQfxoc96v05KW3clk7vvgP0qfDit9DmfQ==}
+  '@vitest/coverage-v8@4.1.7':
+    resolution: {integrity: sha512-qsYPeXc5Q9dFLd1i8Ap+Bx8sQgcp+rFVQo4R0dDsWNBzl26ldVF1qOO+RL24K7FDrR6pA+50XedRLSoSG24bVQ==}
     peerDependencies:
-      '@vitest/browser': 2.1.9
-      vitest: 2.1.9
+      '@vitest/browser': 4.1.7
+      vitest: 4.1.7
     peerDependenciesMeta:
       '@vitest/browser':
         optional: true
 
-  '@vitest/expect@2.1.9':
-    resolution: {integrity: sha512-UJCIkTBenHeKT1TTlKMJWy1laZewsRIzYighyYiJKZreqtdxSos/S1t+ktRMQWu2CKqaarrkeszJx1cgC5tGZw==}
+  '@vitest/expect@4.1.7':
+    resolution: {integrity: sha512-1R+tw0ortHEbZDGMymm+pN7/AFQ/RkFFdtd7EN+VBpynKmLbP8A3rpEXdshBJ7+8hQ9zBJh/i1s0yKNtxAnU7w==}
 
-  '@vitest/mocker@2.1.9':
-    resolution: {integrity: sha512-tVL6uJgoUdi6icpxmdrn5YNo3g3Dxv+IHJBr0GXHaEdTcw3F+cPKnsXFhli6nO+f/6SDKPHEK1UN+k+TQv0Ehg==}
+  '@vitest/mocker@4.1.7':
+    resolution: {integrity: sha512-vY7nuamKgfvpA1Koa3oYIw/k7D6kZnpGyNMZW8loow2bsBYla1TFdqTaXncWdRn4pgwNs+90RhnXhJScDwQeJA==}
     peerDependencies:
       msw: ^2.4.9
-      vite: ^5.0.0
+      vite: ^6.0.0 || ^7.0.0 || ^8.0.0
     peerDependenciesMeta:
       msw:
         optional: true
       vite:
         optional: true
 
-  '@vitest/pretty-format@2.1.9':
-    resolution: {integrity: sha512-KhRIdGV2U9HOUzxfiHmY8IFHTdqtOhIzCpd8WRdJiE7D/HUcZVD0EgQCVjm+Q9gkUXWgBvMmTtZgIG48wq7sOQ==}
+  '@vitest/pretty-format@4.1.7':
+    resolution: {integrity: sha512-umgCarTOYQWIaDMvGDRZij+6b9oVeLIyJzfN+AS88e0ZOU3QTgNNSTtjQOpcvWr3np1N0j4WgZj+sb3oYBDscw==}
 
-  '@vitest/runner@2.1.9':
-    resolution: {integrity: sha512-ZXSSqTFIrzduD63btIfEyOmNcBmQvgOVsPNPe0jYtESiXkhd8u2erDLnMxmGrDCwHCCHE7hxwRDCT3pt0esT4g==}
+  '@vitest/runner@4.1.7':
+    resolution: {integrity: sha512-BapjmAQ2aI78WdMEfeUWivnfVzB+VPGwWRQcJE0OUq7qEeEcBsCSf+0T5iREBNE5nBb4wA5Ya0W6IA+sghdEFw==}
 
-  '@vitest/snapshot@2.1.9':
-    resolution: {integrity: sha512-oBO82rEjsxLNJincVhLhaxxZdEtV0EFHMK5Kmx5sJ6H9L183dHECjiefOAdnqpIgT5eZwT04PoggUnW88vOBNQ==}
+  '@vitest/snapshot@4.1.7':
+    resolution: {integrity: sha512-ZacLzja+TmJeZ1h14xW2FB/WpeimUD3haBXQPyJqxvo8jQTmfeA8zv58mtjN2C7EHXZDYVcVYdYmAxjkWVvKCw==}
 
-  '@vitest/spy@2.1.9':
-    resolution: {integrity: sha512-E1B35FwzXXTs9FHNK6bDszs7mtydNi5MIfUWpceJ8Xbfb1gBMscAnwLbEu+B44ed6W3XjL9/ehLPHR1fkf1KLQ==}
+  '@vitest/spy@4.1.7':
+    resolution: {integrity: sha512-kbkI5LMWakyuTIvs6fUJ5qdIVb1XVKsYJAT4OJ938cHMROYMSfmoQdZy0aaAnjbbc8F61vkoTqz/Az+/HiIu5Q==}
 
-  '@vitest/utils@2.1.9':
-    resolution: {integrity: sha512-v0psaMSkNJ3A2NMrUEHFRzJtDPFn+/VWZ5WxImB21T9fjucJRmS7xCS3ppEnARb9y11OAzaD+P2Ps+b+BGX5iQ==}
+  '@vitest/utils@4.1.7':
+    resolution: {integrity: sha512-T532WBu791cBxJlCl6SO+J14l81DQx6uQHm1bQbmCDY7nqlEIgkza/UFnSBNaUtSf41unldDFjdOBYEQC4b5Hw==}
 
   acorn-jsx@5.3.2:
     resolution: {integrity: sha512-rq9s+JNhf0IChjtDXxllJ7g41oZk5SlXtp0LHwyA5cejwn7vKmKp4pPri6YEePv2PU65sAsegbXtIinmDFDXgQ==}
@@ -1246,18 +1105,6 @@ packages:
     resolution: {integrity: sha512-quJQXlTSUGL2LH9SUXo8VwsY4soanhgo6LNSm84E1LBcE8s3O0wpdiRzyR9z/ZZJMlMWv37qOOb9pdJlMUEKFQ==}
     engines: {node: '>=8'}
 
-  ansi-regex@6.0.1:
-    resolution: {integrity: sha512-n5M855fKb2SsfMIiFFoVrABHJC8QtHwVx+mHWP3QcEqBHYienj5dHSgjbxtC0WEZXYt4wcD6zrQElDPhFuZgfA==}
-    engines: {node: '>=12'}
-
-  ansi-styles@4.3.0:
-    resolution: {integrity: sha512-zbB9rCJAT1rbjiVDb2hqKFHNYLxgtk8NURxZ3IZwD3F6NtxbXZQCnnSi1Lkx+IDohdPlFp222wVALIheZJQSEg==}
-    engines: {node: '>=8'}
-
-  ansi-styles@6.2.1:
-    resolution: {integrity: sha512-bN798gFfQX+viw3R7yrGWRqnrN2oRkEkUjjl4JNn4E8GxxbjtG3FbrEIIY3l8/hrwUwIeCZvi4QuOTP4MErVug==}
-    engines: {node: '>=12'}
-
   ansis@4.1.0:
     resolution: {integrity: sha512-BGcItUBWSMRgOCe+SVZJ+S7yTRG0eGt9cXAHev72yuGcY23hnLA7Bky5L/xLyPINoSN95geovfBkqoTlNZYa7w==}
     engines: {node: '>=14'}
@@ -1284,6 +1131,9 @@ packages:
     resolution: {integrity: sha512-Izi8RQcffqCeNVgFigKli1ssklIbpHnCYc6AknXGYoB6grJqyeby7jv12JUQgmTAnIDnbck1uxksT4dzN3PWBA==}
     engines: {node: '>=12'}
 
+  ast-v8-to-istanbul@1.0.0:
+    resolution: {integrity: sha512-1fSfIwuDICFA4LKkCzRPO7F0hzFf0B7+Xqrl27ynQaa+Rh0e1Es0v6kWHPott3lU10AyAr7oKHa65OppjLn3Rg==}
+
   asynckit@0.4.0:
     resolution: {integrity: sha512-Oei9OH4tRh0YqU3GxhX79dM/mwVgvbZJaSNaRk+bshkj0S5cfHcgYakreBjrHwatXKbz+IoIdYLxrKim2MjW0Q==}
 
@@ -1324,21 +1174,13 @@ packages:
     resolution: {integrity: sha512-tjwM5exMg6BGRI+kNmTntNsvdZS1X8BFYS6tnJ2hdH0kVxM6/eVZ2xy+FqStSWvYmtfFMDLIxurorHwDKfDz5Q==}
     engines: {node: '>=18'}
 
-  cac@6.7.14:
-    resolution: {integrity: sha512-b6Ilus+c3RrdDk+JhLKUAQfzzgLEPy6wcXqS7f/xe1EETvsDP6GORG7SFuOs6cID5YkqchW/LXZbX5bc8j7ZcQ==}
-    engines: {node: '>=8'}
-
-  chai@5.3.3:
-    resolution: {integrity: sha512-4zNhdJD/iOjSH0A05ea+Ke6MU5mmpQcbQsSOkgdaUMJ9zTlDTD/GYlwohmIE2u0gaxHYiVHEn1Fw9mZ/ktJWgw==}
+  chai@6.2.2:
+    resolution: {integrity: sha512-NUPRluOfOiTKBKvWPtSD4PhFvWCqOi0BGStNWs57X9js7XGTprSmFoz5F0tWhR4WPjNeR9jXqdC7/UpSJTnlRg==}
     engines: {node: '>=18'}
 
   chardet@2.1.0:
     resolution: {integrity: sha512-bNFETTG/pM5ryzQ9Ad0lJOTa6HWD/YsScAR3EnCPZRPlQh77JocYktSHOUHelyhm8IARL+o4c4F1bP5KVOjiRA==}
 
-  check-error@2.1.1:
-    resolution: {integrity: sha512-OAlb+T7V4Op9OwdkjmguYRqncdlx5JiofwOAUkmTF+jNdHwzTaTs4sRAGpzLF3oOz5xAyDGrPgeIDFQmDOTiJw==}
-    engines: {node: '>= 16'}
-
   chokidar@3.6.0:
     resolution: {integrity: sha512-7VT13fmjotKpGipCW9JEQAusEPE+Ei8nl6/g4FBAmIm0GOOLMua9NDDo/DWp0ZAxCr3cPq5ZpBqmPAQgDda2Pw==}
     engines: {node: '>= 8.10.0'}
@@ -1351,13 +1193,6 @@ packages:
     resolution: {integrity: sha512-eYm0QWBtUrBWZWG0d386OGAw16Z995PiOVo2B7bjWSbHedGl5e0ZWaq65kOGgUSNesEIDkB9ISbTg/JK9dhCZA==}
     engines: {node: '>=6'}
 
-  color-convert@2.0.1:
-    resolution: {integrity: sha512-RRECPsj7iu/xb5oKYcsFHSppFNnsj/52OVTRKb4zP5onXwVF3zVmmToNcOfGC+CRDpfK/U584fMg38ZHCaElKQ==}
-    engines: {node: '>=7.0.0'}
-
-  color-name@1.1.4:
-    resolution: {integrity: sha512-dOy+3AuW3a2wNbZHIuMZpTcgjGuLU/uBL/ubcZF9OXbDo8ff4O8yVp5Bf0efS8uEoYo5q4Fx7dY9OgQGXgAsQA==}
-
   combined-stream@1.0.8:
     resolution: {integrity: sha512-FQN4MRfuJeHf7cBbBMJFXhKSDq+2kAArBlmRBvcvFE5BB1HZKXtSFASDhdlz9zOYwxh8lDdnvmMOe/+5cdoEdg==}
     engines: {node: '>= 0.8'}
@@ -1368,6 +1203,9 @@ packages:
   commondir@1.0.1:
     resolution: {integrity: sha512-W9pAhw0ja1Edb5GVdIF1mjZw/ASI0AlShXM83UUGe2DVr5TdAPEA1OA8m/g8zWp9x6On7gqufY+FatDbC3MDQg==}
 
+  convert-source-map@2.0.0:
+    resolution: {integrity: sha512-Kvp459HrV2FEJ1CAsi1Ku+MY3kasH19TFykTz2xWmMeq6bk2NU3XXvfJ+Q61m0xktWwt+1HSYf3JZsTms3aRJg==}
+
   cross-spawn@7.0.6:
     resolution: {integrity: sha512-uV2QOWP2nWzsy2aMp8aRibhi9dlzF5Hgh5SHaB9OiTGEyDTiJJyx0uy51QXdyWbtAHNua4XJzUKca3OzKUd3vA==}
     engines: {node: '>= 8'}
@@ -1400,10 +1238,6 @@ packages:
   decimal.js@10.4.3:
     resolution: {integrity: sha512-VBBaLc1MgL5XpzgIP7ny5Z6Nx3UrRkIViUkPUdtl9aya5amy3De1gsUUSB1g3+3sExYNjCAsAznmukyxCb1GRA==}
 
-  deep-eql@5.0.2:
-    resolution: {integrity: sha512-h5k/5U50IJJFpzfL6nO9jaaumfjO/f2NjK/oYB2Djzm4p9L+3T9qWpZqZ2hAbLPuuYq9wrU08WQyBTL5GbPk5Q==}
-    engines: {node: '>=6'}
-
   deep-is@0.1.4:
     resolution: {integrity: sha512-oIPzksmTg4/MriiaYGO+okXDT7ztn/w3Eptv/+gSIdMdKsJo0u4CfYNFJPy+4SKMuCqGw2wxnA+URMg3t8a/bQ==}
 
@@ -1453,15 +1287,6 @@ packages:
     peerDependencies:
       typescript: '>=5.0.4 <5.8'
 
-  eastasianwidth@0.2.0:
-    resolution: {integrity: sha512-I88TYZWc9XiYHRQ4/3c5rjjfgkjhLyW2luGIheGERbNQ6OY7yTybanSpDXZa8y7VUP9YmDcYa+eyq4ca7iLqWA==}
-
-  emoji-regex@8.0.0:
-    resolution: {integrity: sha512-MSjYzcWNOA0ewAHpz0MxpYFvwg6yjy1NG3xteoqz644VCo/RPgnr1/GGt+ic3iJTzQ8Eu3TdM14SawnVUmGE6A==}
-
-  emoji-regex@9.2.2:
-    resolution: {integrity: sha512-L18DaJsXSUk2+42pv8mLs5jJT2hqFkFE4j21wOmgbUqsZ2hL72NsUU785g9RXgo3s0ZNgVl42TiHp3ZtOv/Vyg==}
-
   enhanced-resolve@5.22.1:
     resolution: {integrity: sha512-6QEuw3zoX1SJQc7b87aBXke/no+mG2bTBgw29gWMQonLmpEkWoCAVkl+M49e48AZlWzxiDzDZzYdp6kobcyLww==}
     engines: {node: '>=10.13.0'}
@@ -1477,13 +1302,8 @@ packages:
   error-stack-parser-es@1.0.5:
     resolution: {integrity: sha512-5qucVt2XcuGMcEGgWI7i+yZpmpByQ8J1lHhcL7PwqCwu9FPP3VUXzT4ltHe5i2z9dePwEHcDVOAfSnHsOlCXRA==}
 
-  es-module-lexer@1.7.0:
-    resolution: {integrity: sha512-jEQoCwk8hyb2AZziIOLhDqpm5+2ww5uIE6lkO/6jcOCusfk6LhMHpXXfBLXTZ7Ydyt0j4VoUQv6uGNYbdW+kBA==}
-
-  esbuild@0.21.5:
-    resolution: {integrity: sha512-mg3OPMV4hXywwpoDxu3Qda5xCKQi+vCTZq8S9J/EpkhB2HzKXq4SNFZE3+NK93JYxc8VMSep+lOUSC/RVKaBqw==}
-    engines: {node: '>=12'}
-    hasBin: true
+  es-module-lexer@2.1.0:
+    resolution: {integrity: sha512-n27zTYMjYu1aj4MjCWzSP7G9r75utsaoc8m61weK+W8JMBGGQybd43GstCXZ3WNmSFtGT9wi59qQTW6mhTR5LQ==}
 
   esbuild@0.25.11:
     resolution: {integrity: sha512-KohQwyzrKTQmhXDW1PjCv3Tyspn9n5GcY2RTDqeORIdIJY8yKIF7sTSopFmn/wpMPW4rdPXI0UE5LJLuq3bx0Q==}
@@ -1618,8 +1438,8 @@ packages:
     resolution: {integrity: sha512-kVscqXk4OCp68SZ0dkgEKVi6/8ij300KBWTJq32P/dYeWTSwK41WyTxalN1eRmA5Z9UU/LX9D7FWSmV9SAYx6g==}
     engines: {node: '>=0.10.0'}
 
-  expect-type@1.2.2:
-    resolution: {integrity: sha512-JhFGDVJ7tmDJItKhYgJCGLOWjuK9vPxiXoUFLwLDc99NlmklilbiQJwoctZtt13+xMw91MCk/REan6MWHqDjyA==}
+  expect-type@1.3.0:
+    resolution: {integrity: sha512-knvyeauYhqjOYvQ66MznSMs83wmHrCycNEN6Ao+2AeYEfxUIkuiVxdEa1qlGEPK+We3n0THiDciYSsCcgW/DoA==}
     engines: {node: '>=12.0.0'}
 
   extendable-error@0.1.7:
@@ -1673,10 +1493,6 @@ packages:
   flatted@3.2.9:
     resolution: {integrity: sha512-36yxDn5H7OFZQla0/jFJmbIKTdZAQHngCedGxiMmpNfEZM0sdEeT+WczLQrjK6D7o2aiyLYDnkw0R3JK0Qv1RQ==}
 
-  foreground-child@3.3.0:
-    resolution: {integrity: sha512-Ld2g8rrAyMYFXBhEqMz8ZAHBi4J4uS1i/CxGMDnjyFWddMXLVcDp051DZfu+t7+ab7Wv6SMqpWmyFIj5UbfFvg==}
-    engines: {node: '>=14'}
-
   form-data@4.0.0:
     resolution: {integrity: sha512-ETEklSGi5t0QMZuiXoA/Q6vcnxcLQP5vdugSpuAyi6SVGi2clPPp+xgEhuMaHC+zGgn31Kd235W35f7Hykkaww==}
     engines: {node: '>= 6'}
@@ -1713,11 +1529,6 @@ packages:
     resolution: {integrity: sha512-XxwI8EOhVQgWp6iDL+3b0r86f4d6AX6zSU55HfB4ydCEuXLXc5FcYeOu+nnGftS4TEju/11rt4KJPTMgbfmv4A==}
     engines: {node: '>=10.13.0'}
 
-  glob@10.5.0:
-    resolution: {integrity: sha512-DfXN8DfhJ7NH3Oe7cFmu3NCu1wKbkReJ8TorzSAFbSKrlNaQSKfIzqYqVY8zlbs2NLBbWpRiU52GX2PbaBVNkg==}
-    deprecated: Old versions of glob are not supported, and contain widely publicized security vulnerabilities, which have been fixed in the current version. Please update. Support for old versions may be purchased (at exorbitant rates) by contacting i@izs.me
-    hasBin: true
-
   globals@15.15.0:
     resolution: {integrity: sha512-7ACyT3wmyp3I61S4fG682L0VA2RGD9otkqGJIwNUMF1SWUombIIk+af1unuDYgMm082aHYwD+mzJvv9Iu8dsgg==}
     engines: {node: '>=18'}
@@ -1806,10 +1617,6 @@ packages:
     resolution: {integrity: sha512-SbKbANkN603Vi4jEZv49LeVJMn4yGwsbzZworEoyEiutsN3nJYdbO36zfhGJ6QEDpOZIFkDtnq5JRxmvl3jsoQ==}
     engines: {node: '>=0.10.0'}
 
-  is-fullwidth-code-point@3.0.0:
-    resolution: {integrity: sha512-zymm5+u+sCsSWyD9qNaejV3DFvhCKclKdizYaJUuHA83RLjb7nSuGnddCHGv0hk+KY7BMAlsWeK4Ueg6EV6XQg==}
-    engines: {node: '>=8'}
-
   is-glob@4.0.3:
     resolution: {integrity: sha512-xelSayHH36ZgE7ZWhli7pW34hNbNl8Ojv5KVmkJD4hBdD3th8Tfk9vYasLM+mXWOZhFkgZfxhLSnrwRr4elSSg==}
     engines: {node: '>=0.10.0'}
@@ -1858,16 +1665,12 @@ packages:
     resolution: {integrity: sha512-GCfE1mtsHGOELCU8e/Z7YWzpmybrx/+dSTfLrvY8qRmaY6zXTKWn6WQIjaAFw069icm6GVMNkgu0NzI4iPZUNw==}
     engines: {node: '>=10'}
 
-  istanbul-lib-source-maps@5.0.6:
-    resolution: {integrity: sha512-yg2d+Em4KizZC5niWhQaIomgf5WlL4vOOjZ5xGCmF8SnPE/mDWWXgvRExdcpCgh9lLRRa1/fSYp2ymmbJ1pI+A==}
-    engines: {node: '>=10'}
-
-  istanbul-reports@3.1.7:
-    resolution: {integrity: sha512-BewmUXImeuRk2YY0PVbxgKAysvhRPUQE0h5QRM++nVWyubKGV0l8qQ5op8+B2DOmwSe63Jivj0BjkPQVf8fP5g==}
+  istanbul-reports@3.2.0:
+    resolution: {integrity: sha512-HGYWWS/ehqTV3xN10i23tkPkpH46MLCIMFNCaaKNavAXTF1RkqxawEPtnjnGZ6XKSInBKkiOA5BKS+aZiY3AvA==}
     engines: {node: '>=8'}
 
-  jackspeak@3.4.3:
-    resolution: {integrity: sha512-OGlZQpz2yfahA/Rd1Y8Cd9SIEsqvXkLVoSw/cgwhnhFMDbsQFeZYoJJ7bIZBS9BcamUW96asq/npPWugM+RQBw==}
+  js-tokens@10.0.0:
+    resolution: {integrity: sha512-lM/UBzQmfJRo9ABXbPWemivdCW8V2G8FHaHdypQaIy523snUjog0W71ayWXTjiR+ixeMyVHN2XcpnTd/liPg/Q==}
 
   js-yaml@3.14.2:
     resolution: {integrity: sha512-PMSmkqxr106Xa156c2M265Z+FTrPl+oxd/rgOQy2tijQeK5TxQ43psO1ZCwhVOSdnn+RzkzlRz/eY4BgJBYVpg==}
@@ -1988,17 +1791,14 @@ packages:
   lodash.startcase@4.4.0:
     resolution: {integrity: sha512-+WKqsK294HMSc2jEbNgpHpd0JfIBhp7rEV4aqXWqFr6AlXov+SlcgB1Fv01y2kGe3Gc8nMW7VA0SrGuSkRfIEg==}
 
-  loupe@3.2.1:
-    resolution: {integrity: sha512-CdzqowRJCeLU72bHvWqwRBBlLcMEtIvGrlvef74kMnV2AolS9Y8xUv1I0U/MNAWMhBlKIoyuEgoJ0t/bbwHbLQ==}
-
-  lru-cache@10.4.3:
-    resolution: {integrity: sha512-JNAzZcXrCt42VGLuYz0zfAzDfAvJWW6AfYlDBQyDV5DClI2m5sAmK+OIO7s59XfsRsWHp02jAJrRadPRGTt6SQ==}
-
   magic-string@0.30.17:
     resolution: {integrity: sha512-sNPKHvyjVf7gyjwS4xGTaW/mCnF8wnjtifKBEhxfZ7E/S8tQ0rssrwGNn6q8JH/ohItJfSQp9mBtQYuTlH5QnA==}
 
-  magicast@0.3.5:
-    resolution: {integrity: sha512-L0WhttDl+2BOsybvEOLK7fW3UA0OQ0IQ2d6Zl2x/a6vVRs3bAY0ECOSHHeL5jD+SbOpOCUEi0y1DgHEn9Qn1AQ==}
+  magic-string@0.30.21:
+    resolution: {integrity: sha512-vd2F4YUyEXKGcLHoq+TEyCjxueSeHnFxyyjNp80yg0XV4vUhnDer/lvvlqM/arB5bXQN5K2/3oinyCRyx8T2CQ==}
+
+  magicast@0.5.3:
+    resolution: {integrity: sha512-pVKE4UdSQ7DvHzivsCIFx2BJn1mHG6KsyrFcaxFx6tONdneEuThrDx0Cj3AMg58KyN4pzYT+LHOotxDQDjNvkw==}
 
   make-dir@4.0.0:
     resolution: {integrity: sha512-hXdUTZYIVOt1Ex//jAQi+wTZZpUpwBj/0QsOzqegb3rGMMeJiSEu5xLHnYfBrRV4RH2+OCSOO95Is/7x1WJ4bw==}
@@ -2028,10 +1828,6 @@ packages:
     resolution: {integrity: sha512-G6T0ZX48xgozx7587koeX9Ys2NYy6Gmv//P89sEte9V9whIapMNF4idKxnW2QtCcLiTWlb/wfCabAtAFWhhBow==}
     engines: {node: '>=16 || 14 >=14.17'}
 
-  minipass@7.1.2:
-    resolution: {integrity: sha512-qOOzS1cBTWYF4BH8fVePDBOO9iptMnGUEZwNc/cMWnTV2nVLZ7VoNWEPHkYczZA0pdoA7dl6e7FL659nX9S2aw==}
-    engines: {node: '>=16 || 14 >=14.17'}
-
   mri@1.2.0:
     resolution: {integrity: sha512-tzzskb3bG8LvYGFF/mDTpq3jpI6Q9wc3LEmBaghu+DdCssd1FakN7Bc0hVNmEyGq1bq3RgfkCb3cmQLpNPOroA==}
     engines: {node: '>=4'}
@@ -2067,6 +1863,9 @@ packages:
   nwsapi@2.2.12:
     resolution: {integrity: sha512-qXDmcVlZV4XRtKFzddidpfVP4oMSGhga+xdMc25mv8kaLUHtgzCDhUxkrN8exkGdTlLNaXj7CV3GtON7zuGZ+w==}
 
+  obug@2.1.1:
+    resolution: {integrity: sha512-uTqF9MuPraAQ+IsnPf366RG4cP9RtUi7MLO1N3KEc+wb0a6yKpeL0lmk2IB1jY5KHPAlTc6T/JRdC/YqxHNwkQ==}
+
   ohash@2.0.11:
     resolution: {integrity: sha512-RdR9FQrFwNBNXAr4GixM8YaRZRJ5PUWbKYbE5eOsrwAjJW0q2REGcf79oYPsLyskQCZG1PLN+S/K1V00joZAoQ==}
 
@@ -2109,9 +1908,6 @@ packages:
     resolution: {integrity: sha512-R4nPAVTAU0B9D35/Gk3uJf/7XYbQcyohSKdvAxIRSNghFl4e71hVoGnBNQz9cWaXxO2I10KTC+3jMdvvoKw6dQ==}
     engines: {node: '>=6'}
 
-  package-json-from-dist@1.0.0:
-    resolution: {integrity: sha512-dATvCeZN/8wQsGywez1mzHtTlP22H8OEfPrVMLNr4/eGa+ijtLn/6M5f0dY8UKNrC2O9UCU6SSoG3qRKnt7STw==}
-
   package-manager-detector@0.2.11:
     resolution: {integrity: sha512-BEnLolu+yuz22S56CU1SUKq3XC3PkwD5wv4ikR4MfGvnRVcmzXR9DwSlW2fEamyTPyXHomBJRzgapeuBvRNzJQ==}
 
@@ -2129,24 +1925,13 @@ packages:
   path-parse@1.0.7:
     resolution: {integrity: sha512-LDJzPVEEEPR+y48z93A0Ed0yXb8pAByGWo/k5YYdYgpY2/2EsOsksJrq7lOHxryrVOn1ejG6oAp8ahvOIQD8sw==}
 
-  path-scurry@1.11.1:
-    resolution: {integrity: sha512-Xa4Nw17FS9ApQFJ9umLiJS4orGjm7ZzwUrwamcGQuHSzDyth9boKDaycYdDcZDuqYATXw4HFXgaqWTctW/v1HA==}
-    engines: {node: '>=16 || 14 >=14.18'}
-
   path-type@4.0.0:
     resolution: {integrity: sha512-gDKb8aZMDeD/tZWs9P6+q0J9Mwkdl6xMV8TjnGP3qJVJ06bdMgkbBlLU8IdfOsIsFz2BW1rNVT3XuNEl8zPAvw==}
     engines: {node: '>=8'}
 
-  pathe@1.1.2:
-    resolution: {integrity: sha512-whLdWMYL2TwI08hn8/ZqAbrVemu0LNaNNJZX73O6qaIdCTfXutsLhMkjdENX0qhsQ9uIimo4/aQOmXkoon2nDQ==}
-
   pathe@2.0.3:
     resolution: {integrity: sha512-WUjGcAqP1gQacoQe+OBJsFA7Ld4DyXuUIjZ5cc75cLHvJ7dtNsTugphxIADwspS+AraAUePCKrSVtPLFj/F88w==}
 
-  pathval@2.0.0:
-    resolution: {integrity: sha512-vE7JKRyES09KiunauX7nd2Q9/L7lhok4smP9RZTDeD4MVs72Dp2qNFVz39Nz5a0FVEW0BJR6C0DYrq6unoziZA==}
-    engines: {node: '>= 14.16'}
-
   perfect-debounce@2.0.0:
     resolution: {integrity: sha512-fkEH/OBiKrqqI/yIgjR92lMfs2K8105zt/VT6+7eTjNwisrsh47CeIED9z58zI7DfKdH3uHAn25ziRZn3kgAow==}
 
@@ -2368,25 +2153,13 @@ packages:
   stackback@0.0.2:
     resolution: {integrity: sha512-1XMJE5fQo1jGH6Y/7ebnwPOBEkIEnT4QF32d5R1+VXdXveM0IBMJt8zfaxX1P3QhVwrYe+576+jkANtSS2mBbw==}
 
-  std-env@3.9.0:
-    resolution: {integrity: sha512-UGvjygr6F6tpH7o2qyqR6QYpwraIjKSdtzyBdyytFOHmPZY917kwdwLG0RbOjWOnKmnm3PeHjaoLLMie7kPLQw==}
-
-  string-width@4.2.3:
-    resolution: {integrity: sha512-wKyQRQpjJ0sIp62ErSZdGsjMJWsap5oRNihHhu6G7JVO/9jIB6UyevL+tXuOqrng8j/cxKTWyWUwvSTriiZz/g==}
-    engines: {node: '>=8'}
-
-  string-width@5.1.2:
-    resolution: {integrity: sha512-HnLOCR3vjcY8beoNLtcjZ5/nxn2afmME6lhrDrebokqMap+XbeW8n9TXpPDOqdGK5qcI3oT0GKTW6wC7EMiVqA==}
-    engines: {node: '>=12'}
+  std-env@4.1.0:
+    resolution: {integrity: sha512-Rq7ybcX2RuC55r9oaPVEW7/xu3tj8u4GeBYHBWCychFtzMIr86A7e3PPEBPT37sHStKX3+TiX/Fr/ACmJLVlLQ==}
 
   strip-ansi@6.0.1:
     resolution: {integrity: sha512-Y38VPSHcqkFrCpFnQ9vuSXmquuv5oXOKpGeT6aGrr3o3Gc9AlVa6JBfUSOCnbxGGZF+/0ooI7KrPuUSztUdU5A==}
     engines: {node: '>=8'}
 
-  strip-ansi@7.1.0:
-    resolution: {integrity: sha512-iq6eVVI64nQQTRYq2KtEg2d2uU7LElhTJwsH4YzIHZshxlgZms/wIc4VoDQTlG/IvVIrBKG06CrZnp0qv7hkcQ==}
-    engines: {node: '>=12'}
-
   strip-bom@3.0.0:
     resolution: {integrity: sha512-vavAMRXOgBVNF6nyEEmL3DBK19iRpDcoIwW+swQ+CbGiu7lju6t+JklA1MHweoWtadgt4ISVUsXLyDq34ddcwA==}
     engines: {node: '>=4'}
@@ -2424,30 +2197,19 @@ packages:
     engines: {node: '>=10'}
     hasBin: true
 
-  test-exclude@7.0.1:
-    resolution: {integrity: sha512-pFYqmTw68LXVjeWJMST4+borgQP2AyMNbg1BpZh9LbyhUeNkeaPF9gzfPGUAnSMV3qPYdWUwDIjjCLiSDOl7vg==}
-    engines: {node: '>=18'}
-
   tinybench@2.9.0:
     resolution: {integrity: sha512-0+DUvqWMValLmha6lr4kD8iAMK1HzV0/aKnCtWb9v9641TnP/MFb7Pc2bxoxQjTXAErryXVgUOfv2YqNllqGeg==}
 
-  tinyexec@0.3.2:
-    resolution: {integrity: sha512-KQQR9yN7R5+OSwaK0XQoj22pwHoTlgYqmUscPYoknOoWCWfj/5/ABTMRi69FrKU5ffPVh5QcFikpWJI/P1ocHA==}
+  tinyexec@1.1.2:
+    resolution: {integrity: sha512-dAqSqE/RabpBKI8+h26GfLq6Vb3JVXs30XYQjdMjaj/c2tS8IYYMbIzP599KtRj7c57/wYApb3QjgRgXmrCukA==}
+    engines: {node: '>=18'}
 
   tinyglobby@0.2.15:
     resolution: {integrity: sha512-j2Zq4NyQYG5XMST4cbs02Ak8iJUdxRM0XI5QyxXuZOzKOINmWurp3smXu3y5wDcJrptwpSjgXHzIQxR0omXljQ==}
     engines: {node: '>=12.0.0'}
 
-  tinypool@1.1.1:
-    resolution: {integrity: sha512-Zba82s87IFq9A9XmjiX5uZA/ARWDrB03OHlq+Vw1fSdt0I+4/Kutwy8BP4Y/y/aORMo61FQ0vIb5j44vSo5Pkg==}
-    engines: {node: ^18.0.0 || >=20.0.0}
-
-  tinyrainbow@1.2.0:
-    resolution: {integrity: sha512-weEDEq7Z5eTHPDh4xjX789+fHfF+P8boiFB+0vbWzpbnbsEr/GRaohi/uMKxg8RZMXnl1ItAi/IUHWMsjDV7kQ==}
-    engines: {node: '>=14.0.0'}
-
-  tinyspy@3.0.2:
-    resolution: {integrity: sha512-n1cw8k1k0x4pgA2+9XrOkFydTerNcJ1zWCO5Nn9scWHTD+5tp8dghT2x1uduQePZTZgd3Tupf+x9BxJjeJi77Q==}
+  tinyrainbow@3.1.0:
+    resolution: {integrity: sha512-Bf+ILmBgretUrdJxzXM0SgXLZ3XfiaUuOj/IKQHuTXip+05Xn+uyEYdVg0kYDipTBcLrCVyUzAPz7QmArb0mmw==}
     engines: {node: '>=14.0.0'}
 
   tldts-core@6.1.64:
@@ -2457,10 +2219,6 @@ packages:
     resolution: {integrity: sha512-ph4AE5BXWIOsSy9stpoeo7bYe/Cy7VfpciIH4RhVZUPItCJmhqWCN0EVzxd8BOHiyNb42vuJc6NWTjJkg91Tuw==}
     hasBin: true
 
-  to-fast-properties@2.0.0:
-    resolution: {integrity: sha512-/OaKK0xYrs3DmxRYqL/yDc+FxFUVYhDlXMhRmv3z915w2HF1tnN1omB354j8VUGO/hbRzyD6Y3sA7v7GS/ceog==}
-    engines: {node: '>=4'}
-
   to-regex-range@5.0.1:
     resolution: {integrity: sha512-65P7iz6X5yEr1cwcgvQxbbIw7Uk3gOy5dIdtZ4rDveLqhrdJP+Li/Hx6tyK0NEb+2GCyneCMJiGqrADCSNk8sQ==}
     engines: {node: '>=8.0'}
@@ -2555,11 +2313,6 @@ packages:
     peerDependencies:
       vite: ^2.6.0 || ^3.0.0 || ^4.0.0 || ^5.0.0-0 || ^6.0.0-0 || ^7.0.0-0
 
-  vite-node@2.1.9:
-    resolution: {integrity: sha512-AM9aQ/IPrW/6ENLQg3AGY4K1N2TGZdR5e4gu/MmmR2xR3Ll1+dib+nook92g4TV3PXVyeyxdWwtaCAiUL0hMxA==}
-    engines: {node: ^18.0.0 || >=20.0.0}
-    hasBin: true
-
   vite-plugin-devtools-json@1.0.0:
     resolution: {integrity: sha512-MobvwqX76Vqt/O4AbnNMNWoXWGrKUqZbphCUle/J2KXH82yKQiunOeKnz/nqEPosPsoWWPP9FtNuPBSYpiiwkw==}
     peerDependencies:
@@ -2575,37 +2328,6 @@ packages:
       '@nuxt/kit':
         optional: true
 
-  vite@5.4.20:
-    resolution: {integrity: sha512-j3lYzGC3P+B5Yfy/pfKNgVEg4+UtcIJcVRt2cDjIOmhLourAqPqf8P7acgxeiSgUB7E3p2P8/3gNIgDLpwzs4g==}
-    engines: {node: ^18.0.0 || >=20.0.0}
-    hasBin: true
-    peerDependencies:
-      '@types/node': ^18.0.0 || >=20.0.0
-      less: '*'
-      lightningcss: ^1.21.0
-      sass: '*'
-      sass-embedded: '*'
-      stylus: '*'
-      sugarss: '*'
-      terser: ^5.4.0
-    peerDependenciesMeta:
-      '@types/node':
-        optional: true
-      less:
-        optional: true
-      lightningcss:
-        optional: true
-      sass:
-        optional: true
-      sass-embedded:
-        optional: true
-      stylus:
-        optional: true
-      sugarss:
-        optional: true
-      terser:
-        optional: true
-
   vite@7.3.2:
     resolution: {integrity: sha512-Bby3NOsna2jsjfLVOHKes8sGwgl4TT0E6vvpYgnAYDIF/tie7MRaFthmKuHx1NSXjiTueXH3do80FMQgvEktRg==}
     engines: {node: ^20.19.0 || >=22.12.0}
@@ -2654,23 +2376,39 @@ packages:
       vite:
         optional: true
 
-  vitest@2.1.9:
-    resolution: {integrity: sha512-MSmPM9REYqDGBI8439mA4mWhV5sKmDlBKWIYbA3lRb2PTHACE0mgKwA8yQ2xq9vxDTuk4iPrECBAEW2aoFXY0Q==}
-    engines: {node: ^18.0.0 || >=20.0.0}
+  vitest@4.1.7:
+    resolution: {integrity: sha512-flYyaFd2CgoCoU+0UKt3pxksgC+S02iTDN0n3LtqaMeXsI9SBcdNujc2k0DeFLzUn/0k538yNjOSdwgCqcrwJA==}
+    engines: {node: ^20.0.0 || ^22.0.0 || >=24.0.0}
     hasBin: true
     peerDependencies:
       '@edge-runtime/vm': '*'
-      '@types/node': ^18.0.0 || >=20.0.0
-      '@vitest/browser': 2.1.9
-      '@vitest/ui': 2.1.9
+      '@opentelemetry/api': ^1.9.0
+      '@types/node': ^20.0.0 || ^22.0.0 || >=24.0.0
+      '@vitest/browser-playwright': 4.1.7
+      '@vitest/browser-preview': 4.1.7
+      '@vitest/browser-webdriverio': 4.1.7
+      '@vitest/coverage-istanbul': 4.1.7
+      '@vitest/coverage-v8': 4.1.7
+      '@vitest/ui': 4.1.7
       happy-dom: '*'
       jsdom: '*'
+      vite: ^6.0.0 || ^7.0.0 || ^8.0.0
     peerDependenciesMeta:
       '@edge-runtime/vm':
         optional: true
+      '@opentelemetry/api':
+        optional: true
       '@types/node':
         optional: true
-      '@vitest/browser':
+      '@vitest/browser-playwright':
+        optional: true
+      '@vitest/browser-preview':
+        optional: true
+      '@vitest/browser-webdriverio':
+        optional: true
+      '@vitest/coverage-istanbul':
+        optional: true
+      '@vitest/coverage-v8':
         optional: true
       '@vitest/ui':
         optional: true
@@ -2719,14 +2457,6 @@ packages:
     engines: {node: '>=8'}
     hasBin: true
 
-  wrap-ansi@7.0.0:
-    resolution: {integrity: sha512-YVGIj2kamLSTxw6NsZjoBxfSwsn0ycdesmc4p+Q21c5zPuZ1pl+NfxVdxPtdHvmNVOQ6XSYG4AUtyt/Fi7D16Q==}
-    engines: {node: '>=10'}
-
-  wrap-ansi@8.1.0:
-    resolution: {integrity: sha512-si7QWI6zUMq56bESFvagtmzMdGOtoxfR+Sez11Mobfc7tm+VkUckk9bW2UeffTGVUbOksxmSw0AA2gs8g71NCQ==}
-    engines: {node: '>=12'}
-
   ws@8.18.0:
     resolution: {integrity: sha512-8VbfWfHLbbwu3+N6OKsOMpBdT4kXPDDB9cJk2bJ6mh9ucxdlnNvH1e+roYkKmN9Nxw2yjz7VzeO9oOz2zJ04Pw==}
     engines: {node: '>=10.0.0'}
@@ -2765,28 +2495,22 @@ snapshots:
 
   '@aashutoshrathi/word-wrap@1.2.6': {}
 
-  '@ampproject/remapping@2.3.0':
-    dependencies:
-      '@jridgewell/gen-mapping': 0.3.5
-      '@jridgewell/trace-mapping': 0.3.31
-
-  '@babel/helper-string-parser@7.24.8': {}
+  '@babel/helper-string-parser@7.27.1': {}
 
-  '@babel/helper-validator-identifier@7.24.7': {}
+  '@babel/helper-validator-identifier@7.28.5': {}
 
-  '@babel/parser@7.25.4':
+  '@babel/parser@7.29.3':
     dependencies:
-      '@babel/types': 7.25.4
+      '@babel/types': 7.29.0
 
   '@babel/runtime@7.28.4': {}
 
-  '@babel/types@7.25.4':
+  '@babel/types@7.29.0':
     dependencies:
-      '@babel/helper-string-parser': 7.24.8
-      '@babel/helper-validator-identifier': 7.24.7
-      to-fast-properties: 2.0.0
+      '@babel/helper-string-parser': 7.27.1
+      '@babel/helper-validator-identifier': 7.28.5
 
-  '@bcoe/v8-coverage@0.2.3': {}
+  '@bcoe/v8-coverage@1.0.2': {}
 
   '@changesets/apply-release-plan@7.0.14':
     dependencies:
@@ -2939,153 +2663,102 @@ snapshots:
       human-id: 4.1.1
       prettier: 2.8.8
 
-  '@esbuild/aix-ppc64@0.21.5':
-    optional: true
-
   '@esbuild/aix-ppc64@0.25.11':
     optional: true
 
   '@esbuild/aix-ppc64@0.27.7':
     optional: true
 
-  '@esbuild/android-arm64@0.21.5':
-    optional: true
-
   '@esbuild/android-arm64@0.25.11':
     optional: true
 
   '@esbuild/android-arm64@0.27.7':
     optional: true
 
-  '@esbuild/android-arm@0.21.5':
-    optional: true
-
   '@esbuild/android-arm@0.25.11':
     optional: true
 
   '@esbuild/android-arm@0.27.7':
     optional: true
 
-  '@esbuild/android-x64@0.21.5':
-    optional: true
-
   '@esbuild/android-x64@0.25.11':
     optional: true
 
   '@esbuild/android-x64@0.27.7':
     optional: true
 
-  '@esbuild/darwin-arm64@0.21.5':
-    optional: true
-
   '@esbuild/darwin-arm64@0.25.11':
     optional: true
 
   '@esbuild/darwin-arm64@0.27.7':
     optional: true
 
-  '@esbuild/darwin-x64@0.21.5':
-    optional: true
-
   '@esbuild/darwin-x64@0.25.11':
     optional: true
 
   '@esbuild/darwin-x64@0.27.7':
     optional: true
 
-  '@esbuild/freebsd-arm64@0.21.5':
-    optional: true
-
   '@esbuild/freebsd-arm64@0.25.11':
     optional: true
 
   '@esbuild/freebsd-arm64@0.27.7':
     optional: true
 
-  '@esbuild/freebsd-x64@0.21.5':
-    optional: true
-
   '@esbuild/freebsd-x64@0.25.11':
     optional: true
 
   '@esbuild/freebsd-x64@0.27.7':
     optional: true
 
-  '@esbuild/linux-arm64@0.21.5':
-    optional: true
-
   '@esbuild/linux-arm64@0.25.11':
     optional: true
 
   '@esbuild/linux-arm64@0.27.7':
     optional: true
 
-  '@esbuild/linux-arm@0.21.5':
-    optional: true
-
   '@esbuild/linux-arm@0.25.11':
     optional: true
 
   '@esbuild/linux-arm@0.27.7':
     optional: true
 
-  '@esbuild/linux-ia32@0.21.5':
-    optional: true
-
   '@esbuild/linux-ia32@0.25.11':
     optional: true
 
   '@esbuild/linux-ia32@0.27.7':
     optional: true
 
-  '@esbuild/linux-loong64@0.21.5':
-    optional: true
-
   '@esbuild/linux-loong64@0.25.11':
     optional: true
 
   '@esbuild/linux-loong64@0.27.7':
     optional: true
 
-  '@esbuild/linux-mips64el@0.21.5':
-    optional: true
-
   '@esbuild/linux-mips64el@0.25.11':
     optional: true
 
   '@esbuild/linux-mips64el@0.27.7':
     optional: true
 
-  '@esbuild/linux-ppc64@0.21.5':
-    optional: true
-
   '@esbuild/linux-ppc64@0.25.11':
     optional: true
 
   '@esbuild/linux-ppc64@0.27.7':
     optional: true
 
-  '@esbuild/linux-riscv64@0.21.5':
-    optional: true
-
   '@esbuild/linux-riscv64@0.25.11':
     optional: true
 
   '@esbuild/linux-riscv64@0.27.7':
     optional: true
 
-  '@esbuild/linux-s390x@0.21.5':
-    optional: true
-
   '@esbuild/linux-s390x@0.25.11':
     optional: true
 
   '@esbuild/linux-s390x@0.27.7':
     optional: true
 
-  '@esbuild/linux-x64@0.21.5':
-    optional: true
-
   '@esbuild/linux-x64@0.25.11':
     optional: true
 
@@ -3098,9 +2771,6 @@ snapshots:
   '@esbuild/netbsd-arm64@0.27.7':
     optional: true
 
-  '@esbuild/netbsd-x64@0.21.5':
-    optional: true
-
   '@esbuild/netbsd-x64@0.25.11':
     optional: true
 
@@ -3113,9 +2783,6 @@ snapshots:
   '@esbuild/openbsd-arm64@0.27.7':
     optional: true
 
-  '@esbuild/openbsd-x64@0.21.5':
-    optional: true
-
   '@esbuild/openbsd-x64@0.25.11':
     optional: true
 
@@ -3128,36 +2795,24 @@ snapshots:
   '@esbuild/openharmony-arm64@0.27.7':
     optional: true
 
-  '@esbuild/sunos-x64@0.21.5':
-    optional: true
-
   '@esbuild/sunos-x64@0.25.11':
     optional: true
 
   '@esbuild/sunos-x64@0.27.7':
     optional: true
 
-  '@esbuild/win32-arm64@0.21.5':
-    optional: true
-
   '@esbuild/win32-arm64@0.25.11':
     optional: true
 
   '@esbuild/win32-arm64@0.27.7':
     optional: true
 
-  '@esbuild/win32-ia32@0.21.5':
-    optional: true
-
   '@esbuild/win32-ia32@0.25.11':
     optional: true
 
   '@esbuild/win32-ia32@0.27.7':
     optional: true
 
-  '@esbuild/win32-x64@0.21.5':
-    optional: true
-
   '@esbuild/win32-x64@0.25.11':
     optional: true
 
@@ -3222,17 +2877,6 @@ snapshots:
     dependencies:
       '@isaacs/balanced-match': 4.0.1
 
-  '@isaacs/cliui@8.0.2':
-    dependencies:
-      string-width: 5.1.2
-      string-width-cjs: string-width@4.2.3
-      strip-ansi: 7.1.0
-      strip-ansi-cjs: strip-ansi@6.0.1
-      wrap-ansi: 8.1.0
-      wrap-ansi-cjs: wrap-ansi@7.0.0
-
-  '@istanbuljs/schema@0.1.3': {}
-
   '@jridgewell/gen-mapping@0.3.5':
     dependencies:
       '@jridgewell/set-array': 1.2.1
@@ -3255,6 +2899,8 @@ snapshots:
 
   '@jridgewell/sourcemap-codec@1.5.0': {}
 
+  '@jridgewell/sourcemap-codec@1.5.5': {}
+
   '@jridgewell/trace-mapping@0.3.31':
     dependencies:
       '@jridgewell/resolve-uri': 3.1.1
@@ -3288,9 +2934,6 @@ snapshots:
       '@nodelib/fs.scandir': 2.1.5
       fastq: 1.16.0
 
-  '@pkgjs/parseargs@0.11.0':
-    optional: true
-
   '@playwright/test@1.60.0':
     dependencies:
       playwright: 1.60.0
@@ -3414,6 +3057,8 @@ snapshots:
   '@rollup/rollup-win32-x64-msvc@4.60.1':
     optional: true
 
+  '@standard-schema/spec@1.1.0': {}
+
   '@stylistic/eslint-plugin-js@1.8.0(eslint@10.0.0)':
     dependencies:
       '@types/eslint': 8.56.12
@@ -3469,6 +3114,13 @@ snapshots:
 
   '@types/aria-query@5.0.4': {}
 
+  '@types/chai@5.2.3':
+    dependencies:
+      '@types/deep-eql': 4.0.2
+      assertion-error: 2.0.1
+
+  '@types/deep-eql@4.0.2': {}
+
   '@types/eslint@8.56.12':
     dependencies:
       '@types/estree': 1.0.9
@@ -3592,63 +3244,60 @@ snapshots:
       '@typescript-eslint/types': 8.56.0
       eslint-visitor-keys: 5.0.0
 
-  '@vitest/coverage-v8@2.1.9(vitest@2.1.9(@types/node@20.19.17)(jsdom@25.0.1)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))':
+  '@vitest/coverage-v8@4.1.7(vitest@4.1.7)':
     dependencies:
-      '@ampproject/remapping': 2.3.0
-      '@bcoe/v8-coverage': 0.2.3
-      debug: 4.4.3
+      '@bcoe/v8-coverage': 1.0.2
+      '@vitest/utils': 4.1.7
+      ast-v8-to-istanbul: 1.0.0
       istanbul-lib-coverage: 3.2.2
       istanbul-lib-report: 3.0.1
-      istanbul-lib-source-maps: 5.0.6
-      istanbul-reports: 3.1.7
-      magic-string: 0.30.17
-      magicast: 0.3.5
-      std-env: 3.9.0
-      test-exclude: 7.0.1
-      tinyrainbow: 1.2.0
-      vitest: 2.1.9(@types/node@20.19.17)(jsdom@25.0.1)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
-    transitivePeerDependencies:
-      - supports-color
+      istanbul-reports: 3.2.0
+      magicast: 0.5.3
+      obug: 2.1.1
+      std-env: 4.1.0
+      tinyrainbow: 3.1.0
+      vitest: 4.1.7(@types/node@20.19.17)(@vitest/coverage-v8@4.1.7)(jsdom@25.0.1)(vite@7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
 
-  '@vitest/expect@2.1.9':
+  '@vitest/expect@4.1.7':
     dependencies:
-      '@vitest/spy': 2.1.9
-      '@vitest/utils': 2.1.9
-      chai: 5.3.3
-      tinyrainbow: 1.2.0
+      '@standard-schema/spec': 1.1.0
+      '@types/chai': 5.2.3
+      '@vitest/spy': 4.1.7
+      '@vitest/utils': 4.1.7
+      chai: 6.2.2
+      tinyrainbow: 3.1.0
 
-  '@vitest/mocker@2.1.9(vite@5.4.20(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))':
+  '@vitest/mocker@4.1.7(vite@7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))':
     dependencies:
-      '@vitest/spy': 2.1.9
+      '@vitest/spy': 4.1.7
       estree-walker: 3.0.3
-      magic-string: 0.30.17
+      magic-string: 0.30.21
     optionalDependencies:
-      vite: 5.4.20(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+      vite: 7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
 
-  '@vitest/pretty-format@2.1.9':
+  '@vitest/pretty-format@4.1.7':
     dependencies:
-      tinyrainbow: 1.2.0
+      tinyrainbow: 3.1.0
 
-  '@vitest/runner@2.1.9':
+  '@vitest/runner@4.1.7':
     dependencies:
-      '@vitest/utils': 2.1.9
-      pathe: 1.1.2
+      '@vitest/utils': 4.1.7
+      pathe: 2.0.3
 
-  '@vitest/snapshot@2.1.9':
+  '@vitest/snapshot@4.1.7':
     dependencies:
-      '@vitest/pretty-format': 2.1.9
-      magic-string: 0.30.17
-      pathe: 1.1.2
+      '@vitest/pretty-format': 4.1.7
+      '@vitest/utils': 4.1.7
+      magic-string: 0.30.21
+      pathe: 2.0.3
 
-  '@vitest/spy@2.1.9':
-    dependencies:
-      tinyspy: 3.0.2
+  '@vitest/spy@4.1.7': {}
 
-  '@vitest/utils@2.1.9':
+  '@vitest/utils@4.1.7':
     dependencies:
-      '@vitest/pretty-format': 2.1.9
-      loupe: 3.2.1
-      tinyrainbow: 1.2.0
+      '@vitest/pretty-format': 4.1.7
+      convert-source-map: 2.0.0
+      tinyrainbow: 3.1.0
 
   acorn-jsx@5.3.2(acorn@8.16.0):
     dependencies:
@@ -3673,14 +3322,6 @@ snapshots:
 
   ansi-regex@5.0.1: {}
 
-  ansi-regex@6.0.1: {}
-
-  ansi-styles@4.3.0:
-    dependencies:
-      color-convert: 2.0.1
-
-  ansi-styles@6.2.1: {}
-
   ansis@4.1.0: {}
 
   anymatch@3.1.3:
@@ -3701,6 +3342,12 @@ snapshots:
 
   assertion-error@2.0.1: {}
 
+  ast-v8-to-istanbul@1.0.0:
+    dependencies:
+      '@jridgewell/trace-mapping': 0.3.31
+      estree-walker: 3.0.3
+      js-tokens: 10.0.0
+
   asynckit@0.4.0: {}
 
   axobject-query@4.1.0: {}
@@ -3732,20 +3379,10 @@ snapshots:
     dependencies:
       run-applescript: 7.0.0
 
-  cac@6.7.14: {}
-
-  chai@5.3.3:
-    dependencies:
-      assertion-error: 2.0.1
-      check-error: 2.1.1
-      deep-eql: 5.0.2
-      loupe: 3.2.1
-      pathval: 2.0.0
+  chai@6.2.2: {}
 
   chardet@2.1.0: {}
 
-  check-error@2.1.1: {}
-
   chokidar@3.6.0:
     dependencies:
       anymatch: 3.1.3
@@ -3763,12 +3400,6 @@ snapshots:
 
   clsx@2.1.1: {}
 
-  color-convert@2.0.1:
-    dependencies:
-      color-name: 1.1.4
-
-  color-name@1.1.4: {}
-
   combined-stream@1.0.8:
     dependencies:
       delayed-stream: 1.0.0
@@ -3777,6 +3408,8 @@ snapshots:
 
   commondir@1.0.1: {}
 
+  convert-source-map@2.0.0: {}
+
   cross-spawn@7.0.6:
     dependencies:
       path-key: 3.1.1
@@ -3802,8 +3435,6 @@ snapshots:
 
   decimal.js@10.4.3: {}
 
-  deep-eql@5.0.2: {}
-
   deep-is@0.1.4: {}
 
   deepmerge@4.3.1: {}
@@ -3844,12 +3475,6 @@ snapshots:
       ts-api-utils: 1.3.0(typescript@5.5.4)
       typescript: 5.5.4
 
-  eastasianwidth@0.2.0: {}
-
-  emoji-regex@8.0.0: {}
-
-  emoji-regex@9.2.2: {}
-
   enhanced-resolve@5.22.1:
     dependencies:
       graceful-fs: 4.2.11
@@ -3864,33 +3489,7 @@ snapshots:
 
   error-stack-parser-es@1.0.5: {}
 
-  es-module-lexer@1.7.0: {}
-
-  esbuild@0.21.5:
-    optionalDependencies:
-      '@esbuild/aix-ppc64': 0.21.5
-      '@esbuild/android-arm': 0.21.5
-      '@esbuild/android-arm64': 0.21.5
-      '@esbuild/android-x64': 0.21.5
-      '@esbuild/darwin-arm64': 0.21.5
-      '@esbuild/darwin-x64': 0.21.5
-      '@esbuild/freebsd-arm64': 0.21.5
-      '@esbuild/freebsd-x64': 0.21.5
-      '@esbuild/linux-arm': 0.21.5
-      '@esbuild/linux-arm64': 0.21.5
-      '@esbuild/linux-ia32': 0.21.5
-      '@esbuild/linux-loong64': 0.21.5
-      '@esbuild/linux-mips64el': 0.21.5
-      '@esbuild/linux-ppc64': 0.21.5
-      '@esbuild/linux-riscv64': 0.21.5
-      '@esbuild/linux-s390x': 0.21.5
-      '@esbuild/linux-x64': 0.21.5
-      '@esbuild/netbsd-x64': 0.21.5
-      '@esbuild/openbsd-x64': 0.21.5
-      '@esbuild/sunos-x64': 0.21.5
-      '@esbuild/win32-arm64': 0.21.5
-      '@esbuild/win32-ia32': 0.21.5
-      '@esbuild/win32-x64': 0.21.5
+  es-module-lexer@2.1.0: {}
 
   esbuild@0.25.11:
     optionalDependencies:
@@ -4104,7 +3703,7 @@ snapshots:
 
   esutils@2.0.3: {}
 
-  expect-type@1.2.2: {}
+  expect-type@1.3.0: {}
 
   extendable-error@0.1.7: {}
 
@@ -4155,11 +3754,6 @@ snapshots:
 
   flatted@3.2.9: {}
 
-  foreground-child@3.3.0:
-    dependencies:
-      cross-spawn: 7.0.6
-      signal-exit: 4.1.0
-
   form-data@4.0.0:
     dependencies:
       asynckit: 0.4.0
@@ -4198,15 +3792,6 @@ snapshots:
     dependencies:
       is-glob: 4.0.3
 
-  glob@10.5.0:
-    dependencies:
-      foreground-child: 3.3.0
-      jackspeak: 3.4.3
-      minimatch: 9.0.5
-      minipass: 7.1.2
-      package-json-from-dist: 1.0.0
-      path-scurry: 1.11.1
-
   globals@15.15.0: {}
 
   globals@16.3.0: {}
@@ -4284,8 +3869,6 @@ snapshots:
 
   is-extglob@2.1.1: {}
 
-  is-fullwidth-code-point@3.0.0: {}
-
   is-glob@4.0.3:
     dependencies:
       is-extglob: 2.1.1
@@ -4328,24 +3911,12 @@ snapshots:
       make-dir: 4.0.0
       supports-color: 7.2.0
 
-  istanbul-lib-source-maps@5.0.6:
-    dependencies:
-      '@jridgewell/trace-mapping': 0.3.31
-      debug: 4.4.3
-      istanbul-lib-coverage: 3.2.2
-    transitivePeerDependencies:
-      - supports-color
-
-  istanbul-reports@3.1.7:
+  istanbul-reports@3.2.0:
     dependencies:
       html-escaper: 2.0.2
       istanbul-lib-report: 3.0.1
 
-  jackspeak@3.4.3:
-    dependencies:
-      '@isaacs/cliui': 8.0.2
-    optionalDependencies:
-      '@pkgjs/parseargs': 0.11.0
+  js-tokens@10.0.0: {}
 
   js-yaml@3.14.2:
     dependencies:
@@ -4463,18 +4034,18 @@ snapshots:
 
   lodash.startcase@4.4.0: {}
 
-  loupe@3.2.1: {}
-
-  lru-cache@10.4.3: {}
-
   magic-string@0.30.17:
     dependencies:
       '@jridgewell/sourcemap-codec': 1.5.0
 
-  magicast@0.3.5:
+  magic-string@0.30.21:
+    dependencies:
+      '@jridgewell/sourcemap-codec': 1.5.5
+
+  magicast@0.5.3:
     dependencies:
-      '@babel/parser': 7.25.4
-      '@babel/types': 7.25.4
+      '@babel/parser': 7.29.3
+      '@babel/types': 7.29.0
       source-map-js: 1.2.1
 
   make-dir@4.0.0:
@@ -4502,8 +4073,6 @@ snapshots:
     dependencies:
       brace-expansion: 2.0.2
 
-  minipass@7.1.2: {}
-
   mri@1.2.0: {}
 
   mrmime@2.0.0: {}
@@ -4523,6 +4092,8 @@ snapshots:
 
   nwsapi@2.2.12: {}
 
+  obug@2.1.1: {}
+
   ohash@2.0.11: {}
 
   open@10.2.0:
@@ -4567,8 +4138,6 @@ snapshots:
 
   p-try@2.2.0: {}
 
-  package-json-from-dist@1.0.0: {}
-
   package-manager-detector@0.2.11:
     dependencies:
       quansync: 0.2.11
@@ -4583,19 +4152,10 @@ snapshots:
 
   path-parse@1.0.7: {}
 
-  path-scurry@1.11.1:
-    dependencies:
-      lru-cache: 10.4.3
-      minipass: 7.1.2
-
   path-type@4.0.0: {}
 
-  pathe@1.1.2: {}
-
   pathe@2.0.3: {}
 
-  pathval@2.0.0: {}
-
   perfect-debounce@2.0.0: {}
 
   picocolors@1.1.1: {}
@@ -4798,28 +4358,12 @@ snapshots:
 
   stackback@0.0.2: {}
 
-  std-env@3.9.0: {}
-
-  string-width@4.2.3:
-    dependencies:
-      emoji-regex: 8.0.0
-      is-fullwidth-code-point: 3.0.0
-      strip-ansi: 6.0.1
-
-  string-width@5.1.2:
-    dependencies:
-      eastasianwidth: 0.2.0
-      emoji-regex: 9.2.2
-      strip-ansi: 7.1.0
+  std-env@4.1.0: {}
 
   strip-ansi@6.0.1:
     dependencies:
       ansi-regex: 5.0.1
 
-  strip-ansi@7.1.0:
-    dependencies:
-      ansi-regex: 6.0.1
-
   strip-bom@3.0.0: {}
 
   supports-color@7.2.0:
@@ -4852,26 +4396,16 @@ snapshots:
       commander: 2.20.3
       source-map-support: 0.5.21
 
-  test-exclude@7.0.1:
-    dependencies:
-      '@istanbuljs/schema': 0.1.3
-      glob: 10.5.0
-      minimatch: 9.0.5
-
   tinybench@2.9.0: {}
 
-  tinyexec@0.3.2: {}
+  tinyexec@1.1.2: {}
 
   tinyglobby@0.2.15:
     dependencies:
       fdir: 6.5.0(picomatch@4.0.4)
       picomatch: 4.0.4
 
-  tinypool@1.1.1: {}
-
-  tinyrainbow@1.2.0: {}
-
-  tinyspy@3.0.2: {}
+  tinyrainbow@3.1.0: {}
 
   tldts-core@6.1.64: {}
 
@@ -4879,8 +4413,6 @@ snapshots:
     dependencies:
       tldts-core: 6.1.64
 
-  to-fast-properties@2.0.0: {}
-
   to-regex-range@5.0.1:
     dependencies:
       is-number: 7.0.0
@@ -4962,24 +4494,6 @@ snapshots:
     dependencies:
       vite: 7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
 
-  vite-node@2.1.9(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0):
-    dependencies:
-      cac: 6.7.14
-      debug: 4.4.3
-      es-module-lexer: 1.7.0
-      pathe: 1.1.2
-      vite: 5.4.20(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
-    transitivePeerDependencies:
-      - '@types/node'
-      - less
-      - lightningcss
-      - sass
-      - sass-embedded
-      - stylus
-      - sugarss
-      - supports-color
-      - terser
-
   vite-plugin-devtools-json@1.0.0(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
     dependencies:
       uuid: 11.1.0
@@ -5000,11 +4514,14 @@ snapshots:
     transitivePeerDependencies:
       - supports-color
 
-  vite@5.4.20(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0):
+  vite@7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0):
     dependencies:
-      esbuild: 0.21.5
+      esbuild: 0.27.7
+      fdir: 6.5.0(picomatch@4.0.4)
+      picomatch: 4.0.4
       postcss: 8.5.9
       rollup: 4.60.1
+      tinyglobby: 0.2.15
     optionalDependencies:
       '@types/node': 20.19.17
       fsevents: 2.3.3
@@ -5031,41 +4548,34 @@ snapshots:
     optionalDependencies:
       vite: 7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
 
-  vitest@2.1.9(@types/node@20.19.17)(jsdom@25.0.1)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0):
-    dependencies:
-      '@vitest/expect': 2.1.9
-      '@vitest/mocker': 2.1.9(vite@5.4.20(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
-      '@vitest/pretty-format': 2.1.9
-      '@vitest/runner': 2.1.9
-      '@vitest/snapshot': 2.1.9
-      '@vitest/spy': 2.1.9
-      '@vitest/utils': 2.1.9
-      chai: 5.3.3
-      debug: 4.4.3
-      expect-type: 1.2.2
-      magic-string: 0.30.17
-      pathe: 1.1.2
-      std-env: 3.9.0
+  vitest@4.1.7(@types/node@20.19.17)(@vitest/coverage-v8@4.1.7)(jsdom@25.0.1)(vite@7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
+    dependencies:
+      '@vitest/expect': 4.1.7
+      '@vitest/mocker': 4.1.7(vite@7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+      '@vitest/pretty-format': 4.1.7
+      '@vitest/runner': 4.1.7
+      '@vitest/snapshot': 4.1.7
+      '@vitest/spy': 4.1.7
+      '@vitest/utils': 4.1.7
+      es-module-lexer: 2.1.0
+      expect-type: 1.3.0
+      magic-string: 0.30.21
+      obug: 2.1.1
+      pathe: 2.0.3
+      picomatch: 4.0.4
+      std-env: 4.1.0
       tinybench: 2.9.0
-      tinyexec: 0.3.2
-      tinypool: 1.1.1
-      tinyrainbow: 1.2.0
-      vite: 5.4.20(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
-      vite-node: 2.1.9(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+      tinyexec: 1.1.2
+      tinyglobby: 0.2.15
+      tinyrainbow: 3.1.0
+      vite: 7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
       why-is-node-running: 2.3.0
     optionalDependencies:
       '@types/node': 20.19.17
+      '@vitest/coverage-v8': 4.1.7(vitest@4.1.7)
       jsdom: 25.0.1
     transitivePeerDependencies:
-      - less
-      - lightningcss
       - msw
-      - sass
-      - sass-embedded
-      - stylus
-      - sugarss
-      - supports-color
-      - terser
 
   w3c-xmlserializer@5.0.0:
     dependencies:
@@ -5102,18 +4612,6 @@ snapshots:
       siginfo: 2.0.0
       stackback: 0.0.2
 
-  wrap-ansi@7.0.0:
-    dependencies:
-      ansi-styles: 4.3.0
-      string-width: 4.2.3
-      strip-ansi: 6.0.1
-
-  wrap-ansi@8.1.0:
-    dependencies:
-      ansi-styles: 6.2.1
-      string-width: 5.1.2
-      strip-ansi: 7.1.0
-
   ws@8.18.0: {}
 
   wsl-utils@0.1.0:
diff --git a/vitest-xhtml-environment.ts b/vitest-xhtml-environment.ts
index dc8b271440..4535f5a5e3 100644
--- a/vitest-xhtml-environment.ts
+++ b/vitest-xhtml-environment.ts
@@ -1,4 +1,4 @@
-import { type Environment, builtinEnvironments } from 'vitest/environments';
+import { type Environment, builtinEnvironments } from 'vitest/runtime';
 
 const xhtml_page = `<?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.0//EN" "http://www.w3.org/TR/xhtml-basic/xhtml-basic10.dtd">
@@ -6,7 +6,7 @@ const xhtml_page = `<?xml version="1.0" encoding="UTF-8"?>
 
 export default <Environment>{
 	name: 'jsdom-xhtml',
-	transformMode: 'web',
+	viteEnvironment: 'client',
 	setup(global, { jsdom = {} }) {
 		return builtinEnvironments.jsdom.setup(global, {
 			jsdom: {
diff --git a/vitest.config.js b/vitest.config.js
index ba1edb355b..116dfae9d8 100644
--- a/vitest.config.js
+++ b/vitest.config.js
@@ -29,6 +29,11 @@ export default defineConfig({
 	test: {
 		dir: '.',
 		reporters: ['dot'],
+		// A handful of dev-mode tests trigger Svelte's `effect_update_depth_exceeded`
+		// guard, which involves ~1000 Error objects per flush for stack tracking —
+		// slow enough under vitest 4's deeper async stacks (and CI's slower workers)
+		// to overrun the 5s default.
+		testTimeout: 30_000,
 		include: [
 			'packages/svelte/**/*.test.ts',
 			'packages/svelte/tests/*/test.ts',

From 1b4c43b8e59e22c1b8185421307fbab91e573866 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Wed, 3 Jun 2026 01:12:25 +0200
Subject: [PATCH 076/222] fix: ignore declaration tags for animation directive
 (#18366)

Fixes #18365
---
 .changeset/tangy-keys-drop.md                          |  5 +++++
 .../phases/2-analyze/visitors/shared/element.js        |  1 +
 .../animation-each-with-declaration-tag/errors.json    |  1 +
 .../animation-each-with-declaration-tag/input.svelte   | 10 ++++++++++
 4 files changed, 17 insertions(+)
 create mode 100644 .changeset/tangy-keys-drop.md
 create mode 100644 packages/svelte/tests/validator/samples/animation-each-with-declaration-tag/errors.json
 create mode 100644 packages/svelte/tests/validator/samples/animation-each-with-declaration-tag/input.svelte

diff --git a/.changeset/tangy-keys-drop.md b/.changeset/tangy-keys-drop.md
new file mode 100644
index 0000000000..38f0c10543
--- /dev/null
+++ b/.changeset/tangy-keys-drop.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: ignore declaration tags for animation directive
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/element.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/element.js
index 725a4aded8..ff02dee02a 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/element.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/element.js
@@ -100,6 +100,7 @@ export function validate_element(node, context) {
 					(n) =>
 						n.type !== 'Comment' &&
 						n.type !== 'ConstTag' &&
+						n.type !== 'DeclarationTag' &&
 						(n.type !== 'Text' || n.data.trim() !== '')
 				).length > 1
 			) {
diff --git a/packages/svelte/tests/validator/samples/animation-each-with-declaration-tag/errors.json b/packages/svelte/tests/validator/samples/animation-each-with-declaration-tag/errors.json
new file mode 100644
index 0000000000..fe51488c70
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/animation-each-with-declaration-tag/errors.json
@@ -0,0 +1 @@
+[]
diff --git a/packages/svelte/tests/validator/samples/animation-each-with-declaration-tag/input.svelte b/packages/svelte/tests/validator/samples/animation-each-with-declaration-tag/input.svelte
new file mode 100644
index 0000000000..680efa7eed
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/animation-each-with-declaration-tag/input.svelte
@@ -0,0 +1,10 @@
+<script>
+  function flip(){}
+</script>
+
+<div>
+  {#each [] as n (n)}
+    {const a = n}
+    <div animate:flip={a}></div>
+  {/each}
+</div>

From 94bd27953e0a5ffef80e9451b27e122d185d093f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Minh=20L=C3=AA?=
 <115204145+DucMinhNe@users.noreply.github.com>
Date: Wed, 3 Jun 2026 09:41:15 +0700
Subject: [PATCH 077/222] docs: fix invalid `rows` CSS property in {#each}
 chess-board example (#18367)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

## Problem

The `{#each}` docs page has a runnable "chess board" example whose
`<style>` block uses an invalid CSS property:

```css
.chess-board {
	display: grid;
	grid-template-columns: repeat(8, 1fr);
	rows: repeat(8, 1fr);   /* ← not a real CSS property */
	...
}
```

There is no `rows` shorthand or longhand in CSS, so this line is
silently dropped by every browser. The example clearly intends an 8×8
grid (note the matching `grid-template-columns` line directly above).

## Fix

`rows` → `grid-template-rows`. One line, in
`documentation/docs/03-template-syntax/03-each.md`. No prose changes.
---
 documentation/docs/03-template-syntax/03-each.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/documentation/docs/03-template-syntax/03-each.md b/documentation/docs/03-template-syntax/03-each.md
index 9fa699d493..5f7f494199 100644
--- a/documentation/docs/03-template-syntax/03-each.md
+++ b/documentation/docs/03-template-syntax/03-each.md
@@ -106,7 +106,7 @@ In case you just want to render something `n` times, you can omit the `as` part:
 	.chess-board {
 		display: grid;
 		grid-template-columns: repeat(8, 1fr);
-		rows: repeat(8, 1fr);
+		grid-template-rows: repeat(8, 1fr);
 		border: 1px solid black;
 		aspect-ratio: 1;
 

From e4bfc5f45af2fb5f5fe3f6ee6169b34a8a9db929 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Wed, 3 Jun 2026 17:31:29 +0200
Subject: [PATCH 078/222] chore: bump esrap dependency (#18372)

Avoid installing the broken 2.2.10 version

Closes #18369
---
 .changeset/soft-moments-exist.md |  5 +++++
 packages/svelte/package.json     |  2 +-
 pnpm-lock.yaml                   | 12 ++++++------
 3 files changed, 12 insertions(+), 7 deletions(-)
 create mode 100644 .changeset/soft-moments-exist.md

diff --git a/.changeset/soft-moments-exist.md b/.changeset/soft-moments-exist.md
new file mode 100644
index 0000000000..71a3148afa
--- /dev/null
+++ b/.changeset/soft-moments-exist.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+chore: bump esrap dependency
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index b7e370dc7d..45bb45c695 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -181,7 +181,7 @@
     "clsx": "^2.1.1",
     "devalue": "^5.8.1",
     "esm-env": "^1.2.1",
-    "esrap": "^2.2.9",
+    "esrap": "^2.2.11",
     "is-reference": "^3.0.3",
     "locate-character": "^3.0.0",
     "magic-string": "^0.30.11",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index a970a9cf6a..a619c24ad6 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -102,8 +102,8 @@ importers:
         specifier: ^1.2.1
         version: 1.2.1
       esrap:
-        specifier: ^2.2.9
-        version: 2.2.9(@typescript-eslint/types@8.59.4)
+        specifier: ^2.2.11
+        version: 2.2.11(@typescript-eslint/types@8.59.4)
       is-reference:
         specifier: ^3.0.3
         version: 3.0.3
@@ -1412,8 +1412,8 @@ packages:
     resolution: {integrity: sha512-Ap6G0WQwcU/LHsvLwON1fAQX9Zp0A2Y6Y/cJBl9r/JbW90Zyg4/zbG6zzKa2OTALELarYHmKu0GhpM5EO+7T0g==}
     engines: {node: '>=0.10'}
 
-  esrap@2.2.9:
-    resolution: {integrity: sha512-4KijP+NxCWthMCUC3qHbE6n4vCjqgJS1uAYKhuT/GWfFTf1Qyive2TgOjep+gzbSzRfnNyaN/UU9YmdOt8Eg0A==}
+  esrap@2.2.11:
+    resolution: {integrity: sha512-gPdx+I+BjYEinNMQaBXFjbaJVyoPMU4ZODg5mE+M4DqVG9VusAVHHjcBX+zqyITlI0DIARwDMMzZwAWj36dRoQ==}
     peerDependencies:
       '@typescript-eslint/types': ^8.2.0
     peerDependenciesMeta:
@@ -3683,9 +3683,9 @@ snapshots:
     dependencies:
       estraverse: 5.3.0
 
-  esrap@2.2.9(@typescript-eslint/types@8.59.4):
+  esrap@2.2.11(@typescript-eslint/types@8.59.4):
     dependencies:
-      '@jridgewell/sourcemap-codec': 1.5.0
+      '@jridgewell/sourcemap-codec': 1.5.5
     optionalDependencies:
       '@typescript-eslint/types': 8.59.4
 

From bdb1a0f847ba4f04252e9d26a7690dbfb0683da7 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Thu, 4 Jun 2026 02:59:57 +0200
Subject: [PATCH 079/222] fix: ensure async block assigns correct nodes to
 effect  (#18371)

If a block has a sole component child, we apply an optimization to not
need a template. But if that sole child is wrapped in `$.async`, it can
happens that the block's effect is assigned the wrong end node.

In the reproduction this happens because we have two components inside a
Child which is rendered only after an async block resolves. In
`$.append` we have logic to not reassign nodes when the active effect
didn't already run, which it has by the time we come across it (because
the async work had to resolve first; we added this in
https://github.com/sveltejs/svelte/pull/17120 to prevent the opposite,
nodes being "rewinded" to an earlier position) and so the second sibling
component's `$.append` will not set its end node to the effect. As a
result the end node is wrong (too early).

To fix this we assign the nodes in `$.async`. We could also use
`compareDocumentPosition` in `$.append` to only ever go forward, but
that feels a bit heavier performance-wise.

---------

Co-authored-by: paoloricciuti <ricciutipaolo@gmail.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/async-hydration-orphan-nodes.md    |  5 +++
 .../src/internal/client/dom/blocks/async.js   |  2 +
 packages/svelte/tests/hydration/test.ts       |  8 ++--
 .../samples/async-sole-if-child/Child.svelte  |  7 ++++
 .../samples/async-sole-if-child/Footer.svelte |  1 +
 .../samples/async-sole-if-child/Header.svelte |  1 +
 .../samples/async-sole-if-child/_config.js    | 38 +++++++++++++++++++
 .../samples/async-sole-if-child/main.svelte   | 11 ++++++
 8 files changed, 69 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/async-hydration-orphan-nodes.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Footer.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Header.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-sole-if-child/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-sole-if-child/main.svelte

diff --git a/.changeset/async-hydration-orphan-nodes.md b/.changeset/async-hydration-orphan-nodes.md
new file mode 100644
index 0000000000..4c35d6b74e
--- /dev/null
+++ b/.changeset/async-hydration-orphan-nodes.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: properly track effect end node for async sibling component
\ No newline at end of file
diff --git a/packages/svelte/src/internal/client/dom/blocks/async.js b/packages/svelte/src/internal/client/dom/blocks/async.js
index 170529a6b9..78e2ed44be 100644
--- a/packages/svelte/src/internal/client/dom/blocks/async.js
+++ b/packages/svelte/src/internal/client/dom/blocks/async.js
@@ -9,6 +9,7 @@ import {
 	set_hydrating,
 	skip_nodes
 } from '../hydration.js';
+import { assign_nodes } from '../template.js';
 
 /**
  * @param {TemplateNode} node
@@ -23,6 +24,7 @@ export function async(node, blockers = [], expressions = [], fn) {
 	if (was_hydrating) {
 		hydrate_next();
 		end = skip_nodes(false);
+		assign_nodes(node, end); // Necessary if this wraps the sole child of a block, else end marker can be wrong
 	}
 
 	if (expressions.length === 0 && blockers.every((b) => b.settled)) {
diff --git a/packages/svelte/tests/hydration/test.ts b/packages/svelte/tests/hydration/test.ts
index d2bf6fde34..0050130817 100644
--- a/packages/svelte/tests/hydration/test.ts
+++ b/packages/svelte/tests/hydration/test.ts
@@ -72,7 +72,7 @@ const { test, run } = suite<HydrationTest>(async (config, cwd) => {
 	const target = window.document.body;
 	const head = window.document.head;
 
-	const rendered = render((await import(`${cwd}/_output/server/main.svelte.js`)).default, {
+	const rendered = await render((await import(`${cwd}/_output/server/main.svelte.js`)).default, {
 		props: config.server_props ?? config.props ?? {},
 		idPrefix: config?.id_prefix
 	});
@@ -80,8 +80,8 @@ const { test, run } = suite<HydrationTest>(async (config, cwd) => {
 	const override = read(`${cwd}/_override.html`);
 	const override_head = read(`${cwd}/_override_head.html`);
 
-	fs.writeFileSync(`${cwd}/_output/body.html`, rendered.html + '\n');
-	target.innerHTML = override ?? rendered.html;
+	fs.writeFileSync(`${cwd}/_output/body.html`, rendered.body + '\n');
+	target.innerHTML = override ?? rendered.body;
 
 	if (rendered.head) {
 		fs.writeFileSync(`${cwd}/_output/head.html`, rendered.head + '\n');
@@ -145,7 +145,7 @@ const { test, run } = suite<HydrationTest>(async (config, cwd) => {
 
 		flushSync();
 
-		const expected = read(`${cwd}/_expected.html`) ?? rendered.html;
+		const expected = read(`${cwd}/_expected.html`) ?? rendered.body;
 		assert_html_equal(target.innerHTML, expected);
 
 		if (rendered.head) {
diff --git a/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Child.svelte b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Child.svelte
new file mode 100644
index 0000000000..304b7bd8a9
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Child.svelte
@@ -0,0 +1,7 @@
+<script>
+	import Header from './Header.svelte';
+	import Footer from './Footer.svelte';
+</script>
+ 
+<Header />
+<Footer />
diff --git a/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Footer.svelte b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Footer.svelte
new file mode 100644
index 0000000000..4c05c3d1ca
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Footer.svelte
@@ -0,0 +1 @@
+<footer>footer</footer>
\ No newline at end of file
diff --git a/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Header.svelte b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Header.svelte
new file mode 100644
index 0000000000..bb4683e48e
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Header.svelte
@@ -0,0 +1 @@
+<header>header</header>
\ No newline at end of file
diff --git a/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/_config.js b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/_config.js
new file mode 100644
index 0000000000..842a314f73
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/_config.js
@@ -0,0 +1,38 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		await tick();
+		const [toggle] = target.querySelectorAll('button');
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>toggle</button>
+				<header>header</header>
+				<footer>footer</footer>
+			`
+		);
+
+		toggle.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>toggle</button>
+			`
+		);
+
+		toggle.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>toggle</button>
+				<header>header</header>
+				<footer>footer</footer>
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/main.svelte
new file mode 100644
index 0000000000..9a061501dd
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/main.svelte
@@ -0,0 +1,11 @@
+<script>
+	import Child from './Child.svelte';
+
+	let show = $state(true);
+</script>
+
+<button onclick={() => (show = !show)}>toggle</button>
+
+{#if show}
+	<Child gate={await Promise.resolve(true)} />
+{/if}

From 3d5c4ab620a597dfa296486e96642cff88bf90ec Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Thu, 4 Jun 2026 03:49:19 +0200
Subject: [PATCH 080/222] fix: prevent false-positive reactivity loss warning
 (#18373)

By checking that current/previous batch are null we filter out false
positives. `reactivity_loss_tracker` is only reset after a microtask, so
if a flush happens before that, we get warnings for things we shouldn't
warn on.

Fixes #18370

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/rare-donkeys-repair.md                |  5 +++++
 .../src/internal/client/reactivity/async.js      |  8 ++++----
 packages/svelte/src/internal/client/runtime.js   |  6 ++++++
 .../_config.js                                   | 15 +++++++++++++++
 .../main.svelte                                  | 16 ++++++++++++++++
 5 files changed, 46 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/rare-donkeys-repair.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-reactivity-loss-no-false-positive-4/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-reactivity-loss-no-false-positive-4/main.svelte

diff --git a/.changeset/rare-donkeys-repair.md b/.changeset/rare-donkeys-repair.md
new file mode 100644
index 0000000000..bd22c564db
--- /dev/null
+++ b/.changeset/rare-donkeys-repair.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: prevent false-positive reactivity loss warning
diff --git a/packages/svelte/src/internal/client/reactivity/async.js b/packages/svelte/src/internal/client/reactivity/async.js
index 32d33d6f7a..13b6e42b3e 100644
--- a/packages/svelte/src/internal/client/reactivity/async.js
+++ b/packages/svelte/src/internal/client/reactivity/async.js
@@ -181,10 +181,10 @@ export async function save(promise) {
  * @returns {Promise<() => T>}
  */
 export async function track_reactivity_loss(promise) {
-	var previous_async_effect = reactivity_loss_tracker;
+	var previous_reactivity_loss_tracker = reactivity_loss_tracker;
 	// Ensure that unrelated reads after an async operation is kicked off don't cause false positives
 	queueMicrotask(() => {
-		if (reactivity_loss_tracker === previous_async_effect) {
+		if (reactivity_loss_tracker === previous_reactivity_loss_tracker) {
 			set_reactivity_loss_tracker(null);
 		}
 	});
@@ -192,12 +192,12 @@ export async function track_reactivity_loss(promise) {
 	var value = await promise;
 
 	return () => {
-		set_reactivity_loss_tracker(previous_async_effect);
+		set_reactivity_loss_tracker(previous_reactivity_loss_tracker);
 		// While this can result in false negatives it also guards against the more important
 		// false positives that would occur if this is the last in a chain of async operations,
 		// and the reactivity_loss_tracker would then stay around until the next async operation happens.
 		queueMicrotask(() => {
-			if (reactivity_loss_tracker === previous_async_effect) {
+			if (reactivity_loss_tracker === previous_reactivity_loss_tracker) {
 				set_reactivity_loss_tracker(null);
 			}
 		});
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 8d70eee43c..227203523e 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -51,6 +51,7 @@ import {
 	batch_values,
 	current_batch,
 	flushSync,
+	previous_batch,
 	schedule_effect
 } from './reactivity/batch.js';
 import { handle_error } from './error-handling.js';
@@ -581,6 +582,11 @@ export function get(signal) {
 		if (
 			!untracking &&
 			reactivity_loss_tracker &&
+			// By checking that current/previous batch are null we filter out false positives.
+			// reactivity_loss_tracker is only reset after a microtask, so if a flush happens
+			// before that, we get warnings for things we shouldn't warn on.
+			current_batch === null &&
+			previous_batch === null &&
 			!reactivity_loss_tracker.warned &&
 			(reactivity_loss_tracker.effect.f & REACTION_IS_UPDATING) === 0 &&
 			!reactivity_loss_tracker.effect_deps.has(signal)
diff --git a/packages/svelte/tests/runtime-runes/samples/async-reactivity-loss-no-false-positive-4/_config.js b/packages/svelte/tests/runtime-runes/samples/async-reactivity-loss-no-false-positive-4/_config.js
new file mode 100644
index 0000000000..4bd8adc9c5
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-reactivity-loss-no-false-positive-4/_config.js
@@ -0,0 +1,15 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	compileOptions: { dev: true },
+	async test({ assert, target, warnings }) {
+		await tick();
+		const [increment] = target.querySelectorAll('button');
+
+		increment.click();
+		await new Promise((resolve) => setTimeout(resolve, 10));
+		assert.htmlEqual(target.innerHTML, '<button>increment</button> 1 1');
+		assert.deepEqual(warnings, []);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-reactivity-loss-no-false-positive-4/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-reactivity-loss-no-false-positive-4/main.svelte
new file mode 100644
index 0000000000..d47d99e652
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-reactivity-loss-no-false-positive-4/main.svelte
@@ -0,0 +1,16 @@
+<script>
+	let x = $state(0);
+	let y = $state(0);
+</script>
+
+<button
+	onclick={() => {
+		x++;
+		queueMicrotask(() => queueMicrotask(() => y++));
+	}}
+>
+	increment
+</button>
+
+{await x}
+{y}

From 51baf1c1af4f02e2a8b009a87d932437f164b612 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Thu, 4 Jun 2026 22:28:18 +0200
Subject: [PATCH 081/222] Version Packages (#18357)

This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.


# Releases
## svelte@5.56.2

### Patch Changes

- fix: properly track effect end node for async sibling component
([#18371](https://github.com/sveltejs/svelte/pull/18371))

- fix: prevent false-positive reactivity loss warning
([#18373](https://github.com/sveltejs/svelte/pull/18373))

- chore: bump esrap dependency
([#18372](https://github.com/sveltejs/svelte/pull/18372))

- fix: ignore declaration tags for animation directive
([#18366](https://github.com/sveltejs/svelte/pull/18366))

- fix: reject pending async deriveds on discard
([#18308](https://github.com/sveltejs/svelte/pull/18308))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/async-hydration-orphan-nodes.md |  5 -----
 .changeset/rare-donkeys-repair.md          |  5 -----
 .changeset/soft-moments-exist.md           |  5 -----
 .changeset/tangy-keys-drop.md              |  5 -----
 .changeset/warm-cougars-behave.md          |  5 -----
 packages/svelte/CHANGELOG.md               | 14 ++++++++++++++
 packages/svelte/package.json               |  2 +-
 packages/svelte/src/version.js             |  2 +-
 8 files changed, 16 insertions(+), 27 deletions(-)
 delete mode 100644 .changeset/async-hydration-orphan-nodes.md
 delete mode 100644 .changeset/rare-donkeys-repair.md
 delete mode 100644 .changeset/soft-moments-exist.md
 delete mode 100644 .changeset/tangy-keys-drop.md
 delete mode 100644 .changeset/warm-cougars-behave.md

diff --git a/.changeset/async-hydration-orphan-nodes.md b/.changeset/async-hydration-orphan-nodes.md
deleted file mode 100644
index 4c35d6b74e..0000000000
--- a/.changeset/async-hydration-orphan-nodes.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: properly track effect end node for async sibling component
\ No newline at end of file
diff --git a/.changeset/rare-donkeys-repair.md b/.changeset/rare-donkeys-repair.md
deleted file mode 100644
index bd22c564db..0000000000
--- a/.changeset/rare-donkeys-repair.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: prevent false-positive reactivity loss warning
diff --git a/.changeset/soft-moments-exist.md b/.changeset/soft-moments-exist.md
deleted file mode 100644
index 71a3148afa..0000000000
--- a/.changeset/soft-moments-exist.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-chore: bump esrap dependency
diff --git a/.changeset/tangy-keys-drop.md b/.changeset/tangy-keys-drop.md
deleted file mode 100644
index 38f0c10543..0000000000
--- a/.changeset/tangy-keys-drop.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: ignore declaration tags for animation directive
diff --git a/.changeset/warm-cougars-behave.md b/.changeset/warm-cougars-behave.md
deleted file mode 100644
index 15e32f7436..0000000000
--- a/.changeset/warm-cougars-behave.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: reject pending async deriveds on discard
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index a8a94bc691..6d36f7b456 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,19 @@
 # svelte
 
+## 5.56.2
+
+### Patch Changes
+
+- fix: properly track effect end node for async sibling component ([#18371](https://github.com/sveltejs/svelte/pull/18371))
+
+- fix: prevent false-positive reactivity loss warning ([#18373](https://github.com/sveltejs/svelte/pull/18373))
+
+- chore: bump esrap dependency ([#18372](https://github.com/sveltejs/svelte/pull/18372))
+
+- fix: ignore declaration tags for animation directive ([#18366](https://github.com/sveltejs/svelte/pull/18366))
+
+- fix: reject pending async deriveds on discard ([#18308](https://github.com/sveltejs/svelte/pull/18308))
+
 ## 5.56.1
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 45bb45c695..a098b2689f 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.56.1",
+  "version": "5.56.2",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 210d48461e..94d9a26dd9 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.56.1';
+export const VERSION = '5.56.2';
 export const PUBLIC_VERSION = '5';

From 3d83c9abe606415c2ceee215c76582ea9bcfa7b1 Mon Sep 17 00:00:00 2001
From: sijie-Z <1683039482@qq.com>
Date: Fri, 5 Jun 2026 21:35:31 +0800
Subject: [PATCH 082/222] fix: add bigint to Primitive type for $state.snapshot
 (#18388)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Fixes #18385

  ## Problem

`$state.snapshot` infers BigInt properties as `never` because `bigint`
is missing
from the `Primitive` type definition. BigInt is a valid JavaScript
primitive and is
  supported by `structuredClone`.

  ## Solution

Added `bigint` to the `Primitive` type in both
`packages/svelte/src/ambient.d.ts` and
  `packages/svelte/types/index.d.ts`.

  ## Before

  ```ts
  const object = $state({ number: 1n });
  const snapshot = $state.snapshot(object);
  // snapshot.number is inferred as never ❌

  After

  const object = $state({ number: 1n });
  const snapshot = $state.snapshot(object);
  // snapshot.number is correctly inferred as bigint ✅

  Tests and linting

  - [x] This is a type-only change, no runtime behavior affected

---------

Co-authored-by: Rich Harris <hello@rich-harris.dev>
---
 .changeset/some-parts-watch.md   | 5 +++++
 packages/svelte/src/ambient.d.ts | 2 +-
 packages/svelte/types/index.d.ts | 2 +-
 3 files changed, 7 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/some-parts-watch.md

diff --git a/.changeset/some-parts-watch.md b/.changeset/some-parts-watch.md
new file mode 100644
index 0000000000..7d19a32f22
--- /dev/null
+++ b/.changeset/some-parts-watch.md
@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+fix: type BigInts in `$state.snapshot(...)` return values
diff --git a/packages/svelte/src/ambient.d.ts b/packages/svelte/src/ambient.d.ts
index bbbc86c997..ed0a004fa1 100644
--- a/packages/svelte/src/ambient.d.ts
+++ b/packages/svelte/src/ambient.d.ts
@@ -24,7 +24,7 @@ declare function $state<T>(initial: T): T;
 declare function $state<T>(): T | undefined;
 
 declare namespace $state {
-	type Primitive = string | number | boolean | null | undefined;
+	type Primitive = string | number | bigint | boolean | null | undefined;
 
 	type TypedArray =
 		| Int8Array
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index 1c3795be80..5f41fabf60 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -3229,7 +3229,7 @@ declare function $state<T>(initial: T): T;
 declare function $state<T>(): T | undefined;
 
 declare namespace $state {
-	type Primitive = string | number | boolean | null | undefined;
+	type Primitive = string | number | bigint | boolean | null | undefined;
 
 	type TypedArray =
 		| Int8Array

From 71a6515bd648202b2795a80e68e7c9c7ac9ad4ee Mon Sep 17 00:00:00 2001
From: sijie-Z <1683039482@qq.com>
Date: Sat, 6 Jun 2026 03:17:49 +0800
Subject: [PATCH 083/222] fix: check boundary exists before calling error
 handler in async derived (#18384)

fixes #18383

I traced the issue to
`packages/svelte/src/internal/client/error-handling.js`, specifically
the `invoke_error_boundary` function. The problem is at line 56 where
`effect.b.error(error)` is called without checking if `effect.b` exists.

What happens is: when an async `$derived` rejects inside a
`<svelte:boundary>`, the error is handled correctly the first time. But
if the boundary is destroyed before the rejection fully settles (e.g.
component unmounts), a subsequent settle tries to call
`effect.b.error()` on a destroyed boundary where `effect.b` is `null`,
causing a `TypeError`.

The fix adds a null check for `effect.b` before calling `error()`. If
the boundary has been destroyed, we skip it and continue bubbling up to
the parent boundary. This way the error still gets handled properly
instead of crashing.

This could also be tested by creating a component with an async
`$derived` that rejects after the component unmounts, but I wanted to
get the fix up first for review.

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/fix-boundary-null.md               |  5 ++++
 .../src/internal/client/error-handling.js     |  6 ++++-
 packages/svelte/src/internal/client/index.js  |  1 -
 .../async-error-boundary-4/Child.svelte       |  6 +++++
 .../samples/async-error-boundary-4/_config.js | 13 +++++++++
 .../async-error-boundary-4/main.svelte        | 27 +++++++++++++++++++
 6 files changed, 56 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/fix-boundary-null.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-error-boundary-4/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-error-boundary-4/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-error-boundary-4/main.svelte

diff --git a/.changeset/fix-boundary-null.md b/.changeset/fix-boundary-null.md
new file mode 100644
index 0000000000..c87a47ce34
--- /dev/null
+++ b/.changeset/fix-boundary-null.md
@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+fix: ignore errors that occur in destroyed effects
diff --git a/packages/svelte/src/internal/client/error-handling.js b/packages/svelte/src/internal/client/error-handling.js
index 5d16759266..7c404dd933 100644
--- a/packages/svelte/src/internal/client/error-handling.js
+++ b/packages/svelte/src/internal/client/error-handling.js
@@ -3,7 +3,7 @@
 import { DEV } from 'esm-env';
 import { FILENAME } from '../../constants.js';
 import { is_firefox } from './dom/operations.js';
-import { ERROR_VALUE, BOUNDARY_EFFECT, REACTION_RAN, EFFECT } from './constants.js';
+import { ERROR_VALUE, BOUNDARY_EFFECT, REACTION_RAN, EFFECT, DESTROYED } from './constants.js';
 import { define_property, get_descriptor } from '../shared/utils.js';
 import { active_effect, active_reaction } from './runtime.js';
 
@@ -45,6 +45,10 @@ export function handle_error(error) {
  * @param {Effect | null} effect
  */
 export function invoke_error_boundary(error, effect) {
+	if (effect !== null && (effect.f & DESTROYED) !== 0) {
+		return;
+	}
+
 	while (effect !== null) {
 		if ((effect.f & BOUNDARY_EFFECT) !== 0) {
 			if ((effect.f & REACTION_RAN) === 0) {
diff --git a/packages/svelte/src/internal/client/index.js b/packages/svelte/src/internal/client/index.js
index 988998d067..fa6f9dda39 100644
--- a/packages/svelte/src/internal/client/index.js
+++ b/packages/svelte/src/internal/client/index.js
@@ -180,4 +180,3 @@ export {
 } from '../shared/validate.js';
 export { strict_equals, equals } from './dev/equality.js';
 export { log_if_contains_state } from './dev/console-log.js';
-export { invoke_error_boundary } from './error-handling.js';
diff --git a/packages/svelte/tests/runtime-runes/samples/async-error-boundary-4/Child.svelte b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-4/Child.svelte
new file mode 100644
index 0000000000..8bfc51bb7a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-4/Child.svelte
@@ -0,0 +1,6 @@
+<script>
+	const data = $derived(await Promise.reject(new Error('oops')));
+	const model = $derived({ title: data.title });
+</script>
+
+<h4>{model.title}</h4>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-error-boundary-4/_config.js b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-4/_config.js
new file mode 100644
index 0000000000..a3cda2f865
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-4/_config.js
@@ -0,0 +1,13 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		const [button] = target.querySelectorAll('button');
+
+		button.click();
+		await tick();
+
+		assert.htmlEqual(target.innerHTML, '<button>show</button><p>error was contained</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-error-boundary-4/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-4/main.svelte
new file mode 100644
index 0000000000..3b5f51742a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-4/main.svelte
@@ -0,0 +1,27 @@
+<script>
+	import Child from './Child.svelte';
+
+	let open = $state(false);
+</script>
+
+<svelte:boundary>
+	<button onclick={() => (open = true)}>show</button>
+
+	{#if open}
+		<svelte:boundary>
+			<Child />
+
+			{#snippet pending()}
+				<p>loading…</p>
+			{/snippet}
+
+			{#snippet failed()}
+				<p>error was contained</p>
+			{/snippet}
+		</svelte:boundary>
+	{/if}
+
+	{#snippet failed()}
+		<p>error escaped containment</p>
+	{/snippet}
+</svelte:boundary>

From a9f48540e236d326714a1148b9d61cf785c0f98a Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Sun, 7 Jun 2026 14:25:58 -0400
Subject: [PATCH 084/222] Version Packages (#18389)

This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.


# Releases
## svelte@5.56.3

### Patch Changes

- fix: ignore errors that occur in destroyed effects
([#18384](https://github.com/sveltejs/svelte/pull/18384))

- fix: type BigInts in `$state.snapshot(...)` return values
([#18388](https://github.com/sveltejs/svelte/pull/18388))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/fix-boundary-null.md | 5 -----
 .changeset/some-parts-watch.md  | 5 -----
 packages/svelte/CHANGELOG.md    | 8 ++++++++
 packages/svelte/package.json    | 2 +-
 packages/svelte/src/version.js  | 2 +-
 5 files changed, 10 insertions(+), 12 deletions(-)
 delete mode 100644 .changeset/fix-boundary-null.md
 delete mode 100644 .changeset/some-parts-watch.md

diff --git a/.changeset/fix-boundary-null.md b/.changeset/fix-boundary-null.md
deleted file mode 100644
index c87a47ce34..0000000000
--- a/.changeset/fix-boundary-null.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-"svelte": patch
----
-
-fix: ignore errors that occur in destroyed effects
diff --git a/.changeset/some-parts-watch.md b/.changeset/some-parts-watch.md
deleted file mode 100644
index 7d19a32f22..0000000000
--- a/.changeset/some-parts-watch.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-"svelte": patch
----
-
-fix: type BigInts in `$state.snapshot(...)` return values
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 6d36f7b456..02dd84ddff 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,13 @@
 # svelte
 
+## 5.56.3
+
+### Patch Changes
+
+- fix: ignore errors that occur in destroyed effects ([#18384](https://github.com/sveltejs/svelte/pull/18384))
+
+- fix: type BigInts in `$state.snapshot(...)` return values ([#18388](https://github.com/sveltejs/svelte/pull/18388))
+
 ## 5.56.2
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index a098b2689f..6bca1bd4a8 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.56.2",
+  "version": "5.56.3",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 94d9a26dd9..b6d4236ff8 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.56.2';
+export const VERSION = '5.56.3';
 export const PUBLIC_VERSION = '5';

From 8ea3ee8c62aed631d5c4bbc0870d491059ed7d03 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Mon, 15 Jun 2026 10:52:21 -0400
Subject: [PATCH 085/222] chore(deps-dev): bump esbuild from 0.25.11 to 0.28.1
 (#18427)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Bumps [esbuild](https://github.com/evanw/esbuild) from 0.25.11 to
0.28.1.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a
href="https://github.com/evanw/esbuild/releases">esbuild's
releases</a>.</em></p>
<blockquote>
<h2>v0.28.1</h2>
<ul>
<li>
<p>Disallow <code>\</code> in local development server HTTP requests (<a
href="https://github.com/evanw/esbuild/security/advisories/GHSA-g7r4-m6w7-qqqr">GHSA-g7r4-m6w7-qqqr</a>)</p>
<p>This release fixes a security issue where HTTP requests to esbuild's
local development server could traverse outside of the serve directory
on Windows using a <code>\</code> backslash character. It happened due
to the use of Go's <code>path.Clean()</code> function, which only
handles Unix-style <code>/</code> characters. HTTP requests with paths
containing <code>\</code> are no longer allowed.</p>
<p>Thanks to <a
href="https://github.com/dellalibera"><code>@​dellalibera</code></a> for
reporting this issue.</p>
</li>
<li>
<p>Add integrity checks to the Deno API (<a
href="https://github.com/evanw/esbuild/security/advisories/GHSA-gv7w-rqvm-qjhr">GHSA-gv7w-rqvm-qjhr</a>)</p>
<p>The previous release of esbuild added integrity checks to esbuild's
npm install script. This release also adds integrity checks to esbuild's
Deno install script. Now esbuild's Deno API will also fail with an error
if the downloaded esbuild binary contains something other than the
expected content.</p>
<p>Note that esbuild's Deno API installs from
<code>registry.npmjs.org</code> by default, but allows the
<code>NPM_CONFIG_REGISTRY</code> environment variable to override this
with a custom package registry. This change means that the esbuild
executable served by <code>NPM_CONFIG_REGISTRY</code> must now match the
expected content.</p>
<p>Thanks to <a
href="https://github.com/sondt99"><code>@​sondt99</code></a> for
reporting this issue.</p>
</li>
<li>
<p>Avoid inlining <code>using</code> and <code>await using</code>
declarations (<a
href="https://redirect.github.com/evanw/esbuild/issues/4482">#4482</a>)</p>
<p>Previously esbuild's minifier sometimes incorrectly inlined
<code>using</code> and <code>await using</code> declarations into
subsequent uses of that declaration, which then fails to dispose of the
resource correctly. This bug happened because inlining was done for
<code>let</code> and <code>const</code> declarations by avoiding doing
it for <code>var</code> declarations, which no longer worked when more
declaration types were added. Here's an example:</p>
<pre lang="js"><code>// Original code
{
  using x = new Resource()
  x.activate()
}
<p>// Old output (with --minify)<br />
new Resource().activate();</p>
<p>// New output (with --minify)<br />
{using e=new Resource;e.activate()}<br />
</code></pre></p>
</li>
<li>
<p>Fix module evaluation when an error is thrown (<a
href="https://redirect.github.com/evanw/esbuild/issues/4461">#4461</a>,
<a
href="https://redirect.github.com/evanw/esbuild/pull/4467">#4467</a>)</p>
<p>If an error is thrown during module evaluation, esbuild previously
didn't preserve the state of the module for subsequent module
references. This was observable if <code>import()</code> or
<code>require()</code> is used to import a module multiple times. The
thrown error is supposed to be thrown by every call to
<code>import()</code> or <code>require()</code>, not just the first.
With this release, esbuild will now throw the same error every time you
call <code>import()</code> or <code>require()</code> on a module that
throws during its evaluation.</p>
</li>
<li>
<p>Fix some edge cases around the <code>new</code> operator (<a
href="https://redirect.github.com/evanw/esbuild/issues/4477">#4477</a>)</p>
<p>Previously esbuild incorrectly printed certain edge cases involving
complex expressions inside the target of a <code>new</code> expression
(specifically an optional chain and/or a tagged template literal). The
generated code for the <code>new</code> target was not correctly wrapped
with parentheses, and either contained a syntax error or had different
semantics. These edge cases have been fixed so that they now correctly
wrap the <code>new</code> target in parentheses. Here is an example of
some affected code:</p>
<pre lang="js"><code>// Original code
new (foo()`bar`)()
new (foo()?.bar)()
<p>// Old output<br />
new foo()<code>bar</code>();<br />
new (foo())?.bar();</p>
<p></code></pre></p>
</li>
</ul>
<!-- raw HTML omitted -->
</blockquote>
<p>... (truncated)</p>
</details>
<details>
<summary>Changelog</summary>
<p><em>Sourced from <a
href="https://github.com/evanw/esbuild/blob/main/CHANGELOG-2025.md">esbuild's
changelog</a>.</em></p>
<blockquote>
<h1>Changelog: 2025</h1>
<p>This changelog documents all esbuild versions published in the year
2025 (versions 0.25.0 through 0.27.2).</p>
<h2>0.27.2</h2>
<ul>
<li>
<p>Allow import path specifiers starting with <code>#/</code> (<a
href="https://redirect.github.com/evanw/esbuild/pull/4361">#4361</a>)</p>
<p>Previously the specification for <code>package.json</code> disallowed
import path specifiers starting with <code>#/</code>, but this
restriction <a
href="https://redirect.github.com/nodejs/node/pull/60864">has recently
been relaxed</a> and support for it is being added across the JavaScript
ecosystem. One use case is using it for a wildcard pattern such as
mapping <code>#/*</code> to <code>./src/*</code> (previously you had to
use another character such as <code>#_*</code> instead, which was more
confusing). There is some more context in <a
href="https://redirect.github.com/nodejs/node/issues/49182">nodejs/node#49182</a>.</p>
<p>This change was contributed by <a
href="https://github.com/hybrist"><code>@​hybrist</code></a>.</p>
</li>
<li>
<p>Automatically add the <code>-webkit-mask</code> prefix (<a
href="https://redirect.github.com/evanw/esbuild/issues/4357">#4357</a>,
<a
href="https://redirect.github.com/evanw/esbuild/issues/4358">#4358</a>)</p>
<p>This release automatically adds the <code>-webkit-</code> vendor
prefix for the <a
href="https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/Properties/mask"><code>mask</code></a>
CSS shorthand property:</p>
<pre lang="css"><code>/* Original code */
main {
  mask: url(x.png) center/5rem no-repeat
}
<p>/* Old output (with --target=chrome110) */<br />
main {<br />
mask: url(x.png) center/5rem no-repeat;<br />
}</p>
<p>/* New output (with --target=chrome110) */<br />
main {<br />
-webkit-mask: url(x.png) center/5rem no-repeat;<br />
mask: url(x.png) center/5rem no-repeat;<br />
}<br />
</code></pre></p>
<p>This change was contributed by <a
href="https://github.com/BPJEnnova"><code>@​BPJEnnova</code></a>.</p>
</li>
<li>
<p>Additional minification of <code>switch</code> statements (<a
href="https://redirect.github.com/evanw/esbuild/issues/4176">#4176</a>,
<a
href="https://redirect.github.com/evanw/esbuild/issues/4359">#4359</a>)</p>
<p>This release contains additional minification patterns for reducing
<code>switch</code> statements. Here is an example:</p>
<pre lang="js"><code>// Original code
switch (x) {
  case 0:
    foo()
    break
  case 1:
  default:
    bar()
}
</code></pre>
</li>
</ul>
<!-- raw HTML omitted -->
</blockquote>
<p>... (truncated)</p>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="https://github.com/evanw/esbuild/commit/bb9db84c02433fbe37b3509f53f9f3e3cc48725e"><code>bb9db84</code></a>
publish 0.28.1 to npm</li>
<li><a
href="https://github.com/evanw/esbuild/commit/9ff053e53b8eeb990f59355dbea365277ac45ee2"><code>9ff053e</code></a>
security: add integrity checks to the Deno API</li>
<li><a
href="https://github.com/evanw/esbuild/commit/0a9bf2135b67c7e28989a5ba19f0f000805a5ab5"><code>0a9bf21</code></a>
enforce non-negative size in gzip parser</li>
<li><a
href="https://github.com/evanw/esbuild/commit/e2a1a7132058ee067fe736eac15f695861b8654e"><code>e2a1a71</code></a>
security: forbid <code>\\</code> in local dev server requests</li>
<li><a
href="https://github.com/evanw/esbuild/commit/83a2cbfc35809f4fd5152da59572d7bed7739d78"><code>83a2cbf</code></a>
fix <a
href="https://redirect.github.com/evanw/esbuild/issues/4482">#4482</a>:
don't inline <code>using</code> declarations</li>
<li><a
href="https://github.com/evanw/esbuild/commit/308ad745d824c77bc607603451b257d0f2fd9a38"><code>308ad74</code></a>
fix <a
href="https://redirect.github.com/evanw/esbuild/issues/4471">#4471</a>:
renaming of nested <code>var</code> declarations</li>
<li><a
href="https://github.com/evanw/esbuild/commit/f013f5f99a015bce92ec48d49181d4ad3177b29b"><code>f013f5f</code></a>
fix some typos</li>
<li><a
href="https://github.com/evanw/esbuild/commit/aafd6e48b1088336a5f5a17e930be7e840d43d8c"><code>aafd6e4</code></a>
chore: fix some minor issues in comments (<a
href="https://redirect.github.com/evanw/esbuild/issues/4462">#4462</a>)</li>
<li><a
href="https://github.com/evanw/esbuild/commit/15300c30b5e22f7cfcbed850c246d35095658386"><code>15300c3</code></a>
follow up: cjs evaluation fixes</li>
<li><a
href="https://github.com/evanw/esbuild/commit/1bda0c31d7697c0af44b3ab39b81e599e559a395"><code>1bda0c3</code></a>
fix <a
href="https://redirect.github.com/evanw/esbuild/issues/4461">#4461</a>,
fix <a
href="https://redirect.github.com/evanw/esbuild/issues/4467">#4467</a>:
esm evaluation fixes</li>
<li>Additional commits viewable in <a
href="https://github.com/evanw/esbuild/compare/v0.25.11...v0.28.1">compare
view</a></li>
</ul>
</details>
<details>
<summary>Maintainer changes</summary>
<p>This version was pushed to npm by <a
href="https://www.npmjs.com/~GitHub%20Actions">GitHub Actions</a>, a new
releaser for esbuild since your current version.</p>
</details>
<br />


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---
 packages/svelte/package.json |   2 +-
 pnpm-lock.yaml               | 342 ++++++++++++++++++-----------------
 2 files changed, 178 insertions(+), 166 deletions(-)

diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 6bca1bd4a8..eeca8e032e 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -161,7 +161,7 @@
     "@types/node": "^20.11.5",
     "baseline-browser-mapping": "^2.10.32",
     "dts-buddy": "^0.5.5",
-    "esbuild": "^0.25.10",
+    "esbuild": "^0.28.1",
     "rollup": "^4.59.0",
     "source-map": "^0.7.4",
     "tinyglobby": "^0.2.12",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index a619c24ad6..e86c927efe 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -148,8 +148,8 @@ importers:
         specifier: ^0.5.5
         version: 0.5.5(typescript@5.5.4)
       esbuild:
-        specifier: ^0.25.10
-        version: 0.25.11
+        specifier: ^0.28.1
+        version: 0.28.1
       rollup:
         specifier: ^4.59.0
         version: 4.60.1
@@ -285,23 +285,17 @@ packages:
   '@changesets/write@0.4.0':
     resolution: {integrity: sha512-CdTLvIOPiCNuH71pyDu3rA+Q0n65cmAbXnwWH84rKGiFumFzkmHNT8KHTMEchcxN+Kl8I54xGUhJ7l3E7X396Q==}
 
-  '@esbuild/aix-ppc64@0.25.11':
-    resolution: {integrity: sha512-Xt1dOL13m8u0WE8iplx9Ibbm+hFAO0GsU2P34UNoDGvZYkY8ifSiy6Zuc1lYxfG7svWE2fzqCUmFp5HCn51gJg==}
-    engines: {node: '>=18'}
-    cpu: [ppc64]
-    os: [aix]
-
   '@esbuild/aix-ppc64@0.27.7':
     resolution: {integrity: sha512-EKX3Qwmhz1eMdEJokhALr0YiD0lhQNwDqkPYyPhiSwKrh7/4KRjQc04sZ8db+5DVVnZ1LmbNDI1uAMPEUBnQPg==}
     engines: {node: '>=18'}
     cpu: [ppc64]
     os: [aix]
 
-  '@esbuild/android-arm64@0.25.11':
-    resolution: {integrity: sha512-9slpyFBc4FPPz48+f6jyiXOx/Y4v34TUeDDXJpZqAWQn/08lKGeD8aDp9TMn9jDz2CiEuHwfhRmGBvpnd/PWIQ==}
+  '@esbuild/aix-ppc64@0.28.1':
+    resolution: {integrity: sha512-Svl7tq8k/08+p6CXPpRjQ1fKX+1odH/BQbb48fV6fj3CWHhsoIOoY87w1oHXm0qEpkIK3ZfVgp0hed3XBXzXMQ==}
     engines: {node: '>=18'}
-    cpu: [arm64]
-    os: [android]
+    cpu: [ppc64]
+    os: [aix]
 
   '@esbuild/android-arm64@0.27.7':
     resolution: {integrity: sha512-62dPZHpIXzvChfvfLJow3q5dDtiNMkwiRzPylSCfriLvZeq0a1bWChrGx/BbUbPwOrsWKMn8idSllklzBy+dgQ==}
@@ -309,10 +303,10 @@ packages:
     cpu: [arm64]
     os: [android]
 
-  '@esbuild/android-arm@0.25.11':
-    resolution: {integrity: sha512-uoa7dU+Dt3HYsethkJ1k6Z9YdcHjTrSb5NUy66ZfZaSV8hEYGD5ZHbEMXnqLFlbBflLsl89Zke7CAdDJ4JI+Gg==}
+  '@esbuild/android-arm64@0.28.1':
+    resolution: {integrity: sha512-34EGEbCIAgosYz6goLcopX6Mo7NyGv9tfwEM2/7Ce2VcVRk568iSvniGWcUXIy7wEDR1wzolcxcriFVrWYcwBg==}
     engines: {node: '>=18'}
-    cpu: [arm]
+    cpu: [arm64]
     os: [android]
 
   '@esbuild/android-arm@0.27.7':
@@ -321,10 +315,10 @@ packages:
     cpu: [arm]
     os: [android]
 
-  '@esbuild/android-x64@0.25.11':
-    resolution: {integrity: sha512-Sgiab4xBjPU1QoPEIqS3Xx+R2lezu0LKIEcYe6pftr56PqPygbB7+szVnzoShbx64MUupqoE0KyRlN7gezbl8g==}
+  '@esbuild/android-arm@0.28.1':
+    resolution: {integrity: sha512-0k2F129Xdio1TdJfzJ8sy1Q47vUD2NnwdhiAf7drUN1EBTfPf4hsFCtmMgu/6m8JSzsBrlmVjudMBQqOfG8usQ==}
     engines: {node: '>=18'}
-    cpu: [x64]
+    cpu: [arm]
     os: [android]
 
   '@esbuild/android-x64@0.27.7':
@@ -333,11 +327,11 @@ packages:
     cpu: [x64]
     os: [android]
 
-  '@esbuild/darwin-arm64@0.25.11':
-    resolution: {integrity: sha512-VekY0PBCukppoQrycFxUqkCojnTQhdec0vevUL/EDOCnXd9LKWqD/bHwMPzigIJXPhC59Vd1WFIL57SKs2mg4w==}
+  '@esbuild/android-x64@0.28.1':
+    resolution: {integrity: sha512-dbwY7ltSMDWsRatcRpCnES4F+im88OCUgGZjy52shC7GqHRE/cYlxNbB4Z4UpJswpcc4Qxd2oE/ufM0p61IKng==}
     engines: {node: '>=18'}
-    cpu: [arm64]
-    os: [darwin]
+    cpu: [x64]
+    os: [android]
 
   '@esbuild/darwin-arm64@0.27.7':
     resolution: {integrity: sha512-5lckdqeuBPlKUwvoCXIgI2D9/ABmPq3Rdp7IfL70393YgaASt7tbju3Ac+ePVi3KDH6N2RqePfHnXkaDtY9fkw==}
@@ -345,10 +339,10 @@ packages:
     cpu: [arm64]
     os: [darwin]
 
-  '@esbuild/darwin-x64@0.25.11':
-    resolution: {integrity: sha512-+hfp3yfBalNEpTGp9loYgbknjR695HkqtY3d3/JjSRUyPg/xd6q+mQqIb5qdywnDxRZykIHs3axEqU6l1+oWEQ==}
+  '@esbuild/darwin-arm64@0.28.1':
+    resolution: {integrity: sha512-TZbWkQY7kvTAXbXUT7uVACR5cMHsDiSz9z7ZKAX/RTq/WJEk3QyRr0wZpNhBDX+/0CtdqUIJlOiodQcta6tY3Q==}
     engines: {node: '>=18'}
-    cpu: [x64]
+    cpu: [arm64]
     os: [darwin]
 
   '@esbuild/darwin-x64@0.27.7':
@@ -357,11 +351,11 @@ packages:
     cpu: [x64]
     os: [darwin]
 
-  '@esbuild/freebsd-arm64@0.25.11':
-    resolution: {integrity: sha512-CmKjrnayyTJF2eVuO//uSjl/K3KsMIeYeyN7FyDBjsR3lnSJHaXlVoAK8DZa7lXWChbuOk7NjAc7ygAwrnPBhA==}
+  '@esbuild/darwin-x64@0.28.1':
+    resolution: {integrity: sha512-zfdzgK9ACBNZLI/CyHTOx81SyNbM6YXn7rxSgX97VjyiPl9W1i4Ka4fgKECEoFCKGpvBj5qArWIGgQjOwkgskQ==}
     engines: {node: '>=18'}
-    cpu: [arm64]
-    os: [freebsd]
+    cpu: [x64]
+    os: [darwin]
 
   '@esbuild/freebsd-arm64@0.27.7':
     resolution: {integrity: sha512-B48PqeCsEgOtzME2GbNM2roU29AMTuOIN91dsMO30t+Ydis3z/3Ngoj5hhnsOSSwNzS+6JppqWsuhTp6E82l2w==}
@@ -369,10 +363,10 @@ packages:
     cpu: [arm64]
     os: [freebsd]
 
-  '@esbuild/freebsd-x64@0.25.11':
-    resolution: {integrity: sha512-Dyq+5oscTJvMaYPvW3x3FLpi2+gSZTCE/1ffdwuM6G1ARang/mb3jvjxs0mw6n3Lsw84ocfo9CrNMqc5lTfGOw==}
+  '@esbuild/freebsd-arm64@0.28.1':
+    resolution: {integrity: sha512-wG2EA8ENdEI0qhkSZMjfqrdY+ziCYCPMmtZjjIwOmXFjmyzEHn+UUxk5of+SYsjtfs3VpnlC7QLzSI5hY/rOAw==}
     engines: {node: '>=18'}
-    cpu: [x64]
+    cpu: [arm64]
     os: [freebsd]
 
   '@esbuild/freebsd-x64@0.27.7':
@@ -381,11 +375,11 @@ packages:
     cpu: [x64]
     os: [freebsd]
 
-  '@esbuild/linux-arm64@0.25.11':
-    resolution: {integrity: sha512-Qr8AzcplUhGvdyUF08A1kHU3Vr2O88xxP0Tm8GcdVOUm25XYcMPp2YqSVHbLuXzYQMf9Bh/iKx7YPqECs6ffLA==}
+  '@esbuild/freebsd-x64@0.28.1':
+    resolution: {integrity: sha512-i7dZ9vQgnvSCzi/rYCXNgtF/U+eKZNJBzu3eTQbRgHnM7tNSizLOkRFAl3qzVc/Op/u5YkHHa4pf/3DOYHthLQ==}
     engines: {node: '>=18'}
-    cpu: [arm64]
-    os: [linux]
+    cpu: [x64]
+    os: [freebsd]
 
   '@esbuild/linux-arm64@0.27.7':
     resolution: {integrity: sha512-RZPHBoxXuNnPQO9rvjh5jdkRmVizktkT7TCDkDmQ0W2SwHInKCAV95GRuvdSvA7w4VMwfCjUiPwDi0ZO6Nfe9A==}
@@ -393,10 +387,10 @@ packages:
     cpu: [arm64]
     os: [linux]
 
-  '@esbuild/linux-arm@0.25.11':
-    resolution: {integrity: sha512-TBMv6B4kCfrGJ8cUPo7vd6NECZH/8hPpBHHlYI3qzoYFvWu2AdTvZNuU/7hsbKWqu/COU7NIK12dHAAqBLLXgw==}
+  '@esbuild/linux-arm64@0.28.1':
+    resolution: {integrity: sha512-yHs+0uc8+nvEAfAfxrWQKK5peSNzBc4PegcMO0EJ2hT71uA7vB8Ihg2e77R2P7SG5uYjPbHlLLmve4LLLRCf0g==}
     engines: {node: '>=18'}
-    cpu: [arm]
+    cpu: [arm64]
     os: [linux]
 
   '@esbuild/linux-arm@0.27.7':
@@ -405,10 +399,10 @@ packages:
     cpu: [arm]
     os: [linux]
 
-  '@esbuild/linux-ia32@0.25.11':
-    resolution: {integrity: sha512-TmnJg8BMGPehs5JKrCLqyWTVAvielc615jbkOirATQvWWB1NMXY77oLMzsUjRLa0+ngecEmDGqt5jiDC6bfvOw==}
+  '@esbuild/linux-arm@0.28.1':
+    resolution: {integrity: sha512-qVXBOHQS+d5Y722GwJzJUtOLlX7km3CraOaGormF1pDtPd2C/l1SHRPgjLunLGe51Sh5YYWKMFDyV4SxgMQYTQ==}
     engines: {node: '>=18'}
-    cpu: [ia32]
+    cpu: [arm]
     os: [linux]
 
   '@esbuild/linux-ia32@0.27.7':
@@ -417,10 +411,10 @@ packages:
     cpu: [ia32]
     os: [linux]
 
-  '@esbuild/linux-loong64@0.25.11':
-    resolution: {integrity: sha512-DIGXL2+gvDaXlaq8xruNXUJdT5tF+SBbJQKbWy/0J7OhU8gOHOzKmGIlfTTl6nHaCOoipxQbuJi7O++ldrxgMw==}
+  '@esbuild/linux-ia32@0.28.1':
+    resolution: {integrity: sha512-d1z4ZuP0ajrfz/FhGT4vv278rX8KnPPJx8i5+AtK7TYbx9Le9F1hyzurZpkEyjkGa9dUGhQow4C1NmeGvqxN2w==}
     engines: {node: '>=18'}
-    cpu: [loong64]
+    cpu: [ia32]
     os: [linux]
 
   '@esbuild/linux-loong64@0.27.7':
@@ -429,10 +423,10 @@ packages:
     cpu: [loong64]
     os: [linux]
 
-  '@esbuild/linux-mips64el@0.25.11':
-    resolution: {integrity: sha512-Osx1nALUJu4pU43o9OyjSCXokFkFbyzjXb6VhGIJZQ5JZi8ylCQ9/LFagolPsHtgw6himDSyb5ETSfmp4rpiKQ==}
+  '@esbuild/linux-loong64@0.28.1':
+    resolution: {integrity: sha512-M5sRjUVZrkm1OAPR3dlOYzNmN+loZKGVi1VUQGrwuqLcbR6qeAz+famMhjASeH3YVKvZz+zT1jlh/keC3Rj/lg==}
     engines: {node: '>=18'}
-    cpu: [mips64el]
+    cpu: [loong64]
     os: [linux]
 
   '@esbuild/linux-mips64el@0.27.7':
@@ -441,10 +435,10 @@ packages:
     cpu: [mips64el]
     os: [linux]
 
-  '@esbuild/linux-ppc64@0.25.11':
-    resolution: {integrity: sha512-nbLFgsQQEsBa8XSgSTSlrnBSrpoWh7ioFDUmwo158gIm5NNP+17IYmNWzaIzWmgCxq56vfr34xGkOcZ7jX6CPw==}
+  '@esbuild/linux-mips64el@0.28.1':
+    resolution: {integrity: sha512-mRObBZeHh2OxcBFPWE/FjylkRgZdYuiTR3vaTozquCGOH14iP9oN4x4Ge81CoIDYQrXmIxpFumJBu5MtZpnQJQ==}
     engines: {node: '>=18'}
-    cpu: [ppc64]
+    cpu: [mips64el]
     os: [linux]
 
   '@esbuild/linux-ppc64@0.27.7':
@@ -453,10 +447,10 @@ packages:
     cpu: [ppc64]
     os: [linux]
 
-  '@esbuild/linux-riscv64@0.25.11':
-    resolution: {integrity: sha512-HfyAmqZi9uBAbgKYP1yGuI7tSREXwIb438q0nqvlpxAOs3XnZ8RsisRfmVsgV486NdjD7Mw2UrFSw51lzUk1ww==}
+  '@esbuild/linux-ppc64@0.28.1':
+    resolution: {integrity: sha512-slScBsMAb3GFDcdrCgLwZtPYRoH2H/youv10QiZyRjmsP48fznoveWytSgCI/R0ZcUgpc0ZhIUEx6LHts8yrfQ==}
     engines: {node: '>=18'}
-    cpu: [riscv64]
+    cpu: [ppc64]
     os: [linux]
 
   '@esbuild/linux-riscv64@0.27.7':
@@ -465,10 +459,10 @@ packages:
     cpu: [riscv64]
     os: [linux]
 
-  '@esbuild/linux-s390x@0.25.11':
-    resolution: {integrity: sha512-HjLqVgSSYnVXRisyfmzsH6mXqyvj0SA7pG5g+9W7ESgwA70AXYNpfKBqh1KbTxmQVaYxpzA/SvlB9oclGPbApw==}
+  '@esbuild/linux-riscv64@0.28.1':
+    resolution: {integrity: sha512-kw0owk1o0GFETUJyW0jc0G4Yzs0BHZn0JDZ8JRT088vjJYX777BAs1fDGxAC+q831qOs2DTC96mNsG2opdfyyQ==}
     engines: {node: '>=18'}
-    cpu: [s390x]
+    cpu: [riscv64]
     os: [linux]
 
   '@esbuild/linux-s390x@0.27.7':
@@ -477,10 +471,10 @@ packages:
     cpu: [s390x]
     os: [linux]
 
-  '@esbuild/linux-x64@0.25.11':
-    resolution: {integrity: sha512-HSFAT4+WYjIhrHxKBwGmOOSpphjYkcswF449j6EjsjbinTZbp8PJtjsVK1XFJStdzXdy/jaddAep2FGY+wyFAQ==}
+  '@esbuild/linux-s390x@0.28.1':
+    resolution: {integrity: sha512-/lAIjX8aYFRByhh6L5rYtPEDRqa9de/4V/juOXcta5frjvzXO4/sqEtyytse0g3zZFuWu5cDN0MkLz2qRDD2Ag==}
     engines: {node: '>=18'}
-    cpu: [x64]
+    cpu: [s390x]
     os: [linux]
 
   '@esbuild/linux-x64@0.27.7':
@@ -489,11 +483,11 @@ packages:
     cpu: [x64]
     os: [linux]
 
-  '@esbuild/netbsd-arm64@0.25.11':
-    resolution: {integrity: sha512-hr9Oxj1Fa4r04dNpWr3P8QKVVsjQhqrMSUzZzf+LZcYjZNqhA3IAfPQdEh1FLVUJSiu6sgAwp3OmwBfbFgG2Xg==}
+  '@esbuild/linux-x64@0.28.1':
+    resolution: {integrity: sha512-u/anNYF2mmVOEDwLtnQ1wOr3EZ9sTNGLWrsYGYwHWzGA3Si84IOkHXlbWTD1NB+9/1lcnweYKO54uhxZydNzfA==}
     engines: {node: '>=18'}
-    cpu: [arm64]
-    os: [netbsd]
+    cpu: [x64]
+    os: [linux]
 
   '@esbuild/netbsd-arm64@0.27.7':
     resolution: {integrity: sha512-b6pqtrQdigZBwZxAn1UpazEisvwaIDvdbMbmrly7cDTMFnw/+3lVxxCTGOrkPVnsYIosJJXAsILG9XcQS+Yu6w==}
@@ -501,10 +495,10 @@ packages:
     cpu: [arm64]
     os: [netbsd]
 
-  '@esbuild/netbsd-x64@0.25.11':
-    resolution: {integrity: sha512-u7tKA+qbzBydyj0vgpu+5h5AeudxOAGncb8N6C9Kh1N4n7wU1Xw1JDApsRjpShRpXRQlJLb9wY28ELpwdPcZ7A==}
+  '@esbuild/netbsd-arm64@0.28.1':
+    resolution: {integrity: sha512-oks0DYbLwWMmaakTsCb+zL4E+aHRVLom9IJZOAthMQEPiQmydXHkziYEsGYRx0uNV/IjEKGAV941JzH02pflqw==}
     engines: {node: '>=18'}
-    cpu: [x64]
+    cpu: [arm64]
     os: [netbsd]
 
   '@esbuild/netbsd-x64@0.27.7':
@@ -513,11 +507,11 @@ packages:
     cpu: [x64]
     os: [netbsd]
 
-  '@esbuild/openbsd-arm64@0.25.11':
-    resolution: {integrity: sha512-Qq6YHhayieor3DxFOoYM1q0q1uMFYb7cSpLD2qzDSvK1NAvqFi8Xgivv0cFC6J+hWVw2teCYltyy9/m/14ryHg==}
+  '@esbuild/netbsd-x64@0.28.1':
+    resolution: {integrity: sha512-aeL6lAnN89Hz43Mlh1G8ARasbuoYvSITDEx0tHh5b7jJnHcssqgjy9Yx430GDpmCa6OyrKoS0aNRjKundRizGg==}
     engines: {node: '>=18'}
-    cpu: [arm64]
-    os: [openbsd]
+    cpu: [x64]
+    os: [netbsd]
 
   '@esbuild/openbsd-arm64@0.27.7':
     resolution: {integrity: sha512-AFuojMQTxAz75Fo8idVcqoQWEHIXFRbOc1TrVcFSgCZtQfSdc1RXgB3tjOn/krRHENUB4j00bfGjyl2mJrU37A==}
@@ -525,10 +519,10 @@ packages:
     cpu: [arm64]
     os: [openbsd]
 
-  '@esbuild/openbsd-x64@0.25.11':
-    resolution: {integrity: sha512-CN+7c++kkbrckTOz5hrehxWN7uIhFFlmS/hqziSFVWpAzpWrQoAG4chH+nN3Be+Kzv/uuo7zhX716x3Sn2Jduw==}
+  '@esbuild/openbsd-arm64@0.28.1':
+    resolution: {integrity: sha512-MEFJe5C3R8pwXdZ5Y21oo6m7ePiS0d9pWucn99O/wvyJZChoIQKrQDxKrGeW8F5+T0okTHesAmDeiHDTIq0V/Q==}
     engines: {node: '>=18'}
-    cpu: [x64]
+    cpu: [arm64]
     os: [openbsd]
 
   '@esbuild/openbsd-x64@0.27.7':
@@ -537,11 +531,11 @@ packages:
     cpu: [x64]
     os: [openbsd]
 
-  '@esbuild/openharmony-arm64@0.25.11':
-    resolution: {integrity: sha512-rOREuNIQgaiR+9QuNkbkxubbp8MSO9rONmwP5nKncnWJ9v5jQ4JxFnLu4zDSRPf3x4u+2VN4pM4RdyIzDty/wQ==}
+  '@esbuild/openbsd-x64@0.28.1':
+    resolution: {integrity: sha512-i/ZLIOafE0Z8cI/XANJAixoJL/uRAoS2xOA3rb0xN+KK0K177cMAsQYkzHtBrtMXAKuAc7HGgcWiZ/sRC1Nxgw==}
     engines: {node: '>=18'}
-    cpu: [arm64]
-    os: [openharmony]
+    cpu: [x64]
+    os: [openbsd]
 
   '@esbuild/openharmony-arm64@0.27.7':
     resolution: {integrity: sha512-+KrvYb/C8zA9CU/g0sR6w2RBw7IGc5J2BPnc3dYc5VJxHCSF1yNMxTV5LQ7GuKteQXZtspjFbiuW5/dOj7H4Yw==}
@@ -549,11 +543,11 @@ packages:
     cpu: [arm64]
     os: [openharmony]
 
-  '@esbuild/sunos-x64@0.25.11':
-    resolution: {integrity: sha512-nq2xdYaWxyg9DcIyXkZhcYulC6pQ2FuCgem3LI92IwMgIZ69KHeY8T4Y88pcwoLIjbed8n36CyKoYRDygNSGhA==}
+  '@esbuild/openharmony-arm64@0.28.1':
+    resolution: {integrity: sha512-ge+Z7EXFNt2BO1oAMsVpiQ8EwndV9i1xXerAeTIK7AtPs3bKFXQM7nlRxDSIUIMeueR1CNXxqztLzdNeReKBJg==}
     engines: {node: '>=18'}
-    cpu: [x64]
-    os: [sunos]
+    cpu: [arm64]
+    os: [openharmony]
 
   '@esbuild/sunos-x64@0.27.7':
     resolution: {integrity: sha512-ikktIhFBzQNt/QDyOL580ti9+5mL/YZeUPKU2ivGtGjdTYoqz6jObj6nOMfhASpS4GU4Q/Clh1QtxWAvcYKamA==}
@@ -561,11 +555,11 @@ packages:
     cpu: [x64]
     os: [sunos]
 
-  '@esbuild/win32-arm64@0.25.11':
-    resolution: {integrity: sha512-3XxECOWJq1qMZ3MN8srCJ/QfoLpL+VaxD/WfNRm1O3B4+AZ/BnLVgFbUV3eiRYDMXetciH16dwPbbHqwe1uU0Q==}
+  '@esbuild/sunos-x64@0.28.1':
+    resolution: {integrity: sha512-BEjgtECkL3vY+SaSQ6nzVfiALUeFxpawyp8Jmf5PtYhf1Ug40N1h/hxlhts+f1FvSvarEigdxS3BlSMI2PJLcQ==}
     engines: {node: '>=18'}
-    cpu: [arm64]
-    os: [win32]
+    cpu: [x64]
+    os: [sunos]
 
   '@esbuild/win32-arm64@0.27.7':
     resolution: {integrity: sha512-7yRhbHvPqSpRUV7Q20VuDwbjW5kIMwTHpptuUzV+AA46kiPze5Z7qgt6CLCK3pWFrHeNfDd1VKgyP4O+ng17CA==}
@@ -573,10 +567,10 @@ packages:
     cpu: [arm64]
     os: [win32]
 
-  '@esbuild/win32-ia32@0.25.11':
-    resolution: {integrity: sha512-3ukss6gb9XZ8TlRyJlgLn17ecsK4NSQTmdIXRASVsiS2sQ6zPPZklNJT5GR5tE/MUarymmy8kCEf5xPCNCqVOA==}
+  '@esbuild/win32-arm64@0.28.1':
+    resolution: {integrity: sha512-lCv9eK/H6ZJWbE7bh2nw54CZ9M2nupBxJcTsdk/QQnWkdSjKGuxmmH8/GWrlT1eMmZfn4dGcCjRte397WqfQXA==}
     engines: {node: '>=18'}
-    cpu: [ia32]
+    cpu: [arm64]
     os: [win32]
 
   '@esbuild/win32-ia32@0.27.7':
@@ -585,10 +579,10 @@ packages:
     cpu: [ia32]
     os: [win32]
 
-  '@esbuild/win32-x64@0.25.11':
-    resolution: {integrity: sha512-D7Hpz6A2L4hzsRpPaCYkQnGOotdUpDzSGRIv9I+1ITdHROSFUWW95ZPZWQmGka1Fg7W3zFJowyn9WGwMJ0+KPA==}
+  '@esbuild/win32-ia32@0.28.1':
+    resolution: {integrity: sha512-zvb/mB2bSCoJOpoCBgYKKpX6YM6mJBlBUVUtVj41DlZJVEB6/0CKlRYxP5wWl1C1ILiCoAU5wZZ4q1P3qeS6Eg==}
     engines: {node: '>=18'}
-    cpu: [x64]
+    cpu: [ia32]
     os: [win32]
 
   '@esbuild/win32-x64@0.27.7':
@@ -597,6 +591,12 @@ packages:
     cpu: [x64]
     os: [win32]
 
+  '@esbuild/win32-x64@0.28.1':
+    resolution: {integrity: sha512-bm4Mowrv+GXMlpWX++EcXw/iLyd1o3+bJkC2DkWXYVvgZCqD/bSj9ctZeAMC3cIxgjRVR2Dufaiu4YPxr5gW1A==}
+    engines: {node: '>=18'}
+    cpu: [x64]
+    os: [win32]
+
   '@eslint-community/eslint-utils@4.9.1':
     resolution: {integrity: sha512-phrYmNiYppR7znFEdqgfWHXR6NCkZEK7hwWDHZUjit/2/U0r6XvkDl0SYnoM51Hq7FhCGdLDT6zxCCOY1hexsQ==}
     engines: {node: ^12.22.0 || ^14.17.0 || >=16.0.0}
@@ -936,6 +936,7 @@ packages:
   '@svitejs/changesets-changelog-github-compact@1.1.0':
     resolution: {integrity: sha512-qhUGGDHcpbY2zpjW3SwqchuW8J/5EzlPFud7xNntHKA7f3a/mx5+g+ruJKFHSAiVZYo30PALt+AyhmPUNKH/Og==}
     engines: {node: ^14.13.1 || ^16.0.0 || >=18}
+    deprecated: unmaintained
 
   '@types/aria-query@5.0.4':
     resolution: {integrity: sha512-rfT93uj5s0PRL7EzccGMs3brplhcrghnDoV26NqKhCAS1hVo+WdNsPvE/yb6ilfr5hi2MEk6d5EWJTKdxg8jVw==}
@@ -1090,6 +1091,11 @@ packages:
     engines: {node: '>=0.4.0'}
     hasBin: true
 
+  acorn@8.17.0:
+    resolution: {integrity: sha512-xRQbDb9BnwDafYNn6Vwl839DYVjqXYb1XVGtWAZ1kcDc6iwAL4hg3B1dZlRiuENFeO2H53gFG3in621AdERVAg==}
+    engines: {node: '>=0.4.0'}
+    hasBin: true
+
   agent-base@7.1.1:
     resolution: {integrity: sha512-H0TSyFNDMomMNJQBn8wFV5YC/2eJ+VXECwOadZJT554xP6cODZHPX3H9QMQECxvrgiSOP1pHjy1sMWQVYJOUOA==}
     engines: {node: '>= 14'}
@@ -1287,8 +1293,8 @@ packages:
     peerDependencies:
       typescript: '>=5.0.4 <5.8'
 
-  enhanced-resolve@5.22.1:
-    resolution: {integrity: sha512-6QEuw3zoX1SJQc7b87aBXke/no+mG2bTBgw29gWMQonLmpEkWoCAVkl+M49e48AZlWzxiDzDZzYdp6kobcyLww==}
+  enhanced-resolve@5.24.0:
+    resolution: {integrity: sha512-SkE2t82KlkkxQRVMVLAGKxLfORGQfrkx5dkj+vlgXRVNEdPc4eZcR+J/Fvj8C+yKSFH5L0q3NFlyufOVQnCcYQ==}
     engines: {node: '>=10.13.0'}
 
   enquirer@2.4.1:
@@ -1305,13 +1311,13 @@ packages:
   es-module-lexer@2.1.0:
     resolution: {integrity: sha512-n27zTYMjYu1aj4MjCWzSP7G9r75utsaoc8m61weK+W8JMBGGQybd43GstCXZ3WNmSFtGT9wi59qQTW6mhTR5LQ==}
 
-  esbuild@0.25.11:
-    resolution: {integrity: sha512-KohQwyzrKTQmhXDW1PjCv3Tyspn9n5GcY2RTDqeORIdIJY8yKIF7sTSopFmn/wpMPW4rdPXI0UE5LJLuq3bx0Q==}
+  esbuild@0.27.7:
+    resolution: {integrity: sha512-IxpibTjyVnmrIQo5aqNpCgoACA/dTKLTlhMHihVHhdkxKyPO1uBBthumT0rdHmcsk9uMonIWS0m4FljWzILh3w==}
     engines: {node: '>=18'}
     hasBin: true
 
-  esbuild@0.27.7:
-    resolution: {integrity: sha512-IxpibTjyVnmrIQo5aqNpCgoACA/dTKLTlhMHihVHhdkxKyPO1uBBthumT0rdHmcsk9uMonIWS0m4FljWzILh3w==}
+  esbuild@0.28.1:
+    resolution: {integrity: sha512-HrJrvZv5ayxBzPfwphOoNzkzOIIlifzk0KJrGK2c8R4+LKpMtpYLQeUdjnwjWv/LZlkH2laZk+4w78pi99D4Vw==}
     engines: {node: '>=18'}
     hasBin: true
 
@@ -2095,8 +2101,8 @@ packages:
     engines: {node: '>=10'}
     hasBin: true
 
-  semver@7.8.1:
-    resolution: {integrity: sha512-rkVq3IXh+4FDGch+KwzX3aV9W3kO54GyEgpvBzSyctDA6Xtd7RJQV1xmXbeQp5v7+VzLOfVqiutSE6GICgPFvg==}
+  semver@7.8.4:
+    resolution: {integrity: sha512-rUCObTnP32Q08R2uuIrt7r9PlEonuTmtuXYcW6s5kjdlj3xbnwe+21yXptAUYcMAABLkYYTtnmzb3w3EDZfueA==}
     engines: {node: '>=10'}
     hasBin: true
 
@@ -2663,162 +2669,162 @@ snapshots:
       human-id: 4.1.1
       prettier: 2.8.8
 
-  '@esbuild/aix-ppc64@0.25.11':
-    optional: true
-
   '@esbuild/aix-ppc64@0.27.7':
     optional: true
 
-  '@esbuild/android-arm64@0.25.11':
+  '@esbuild/aix-ppc64@0.28.1':
     optional: true
 
   '@esbuild/android-arm64@0.27.7':
     optional: true
 
-  '@esbuild/android-arm@0.25.11':
+  '@esbuild/android-arm64@0.28.1':
     optional: true
 
   '@esbuild/android-arm@0.27.7':
     optional: true
 
-  '@esbuild/android-x64@0.25.11':
+  '@esbuild/android-arm@0.28.1':
     optional: true
 
   '@esbuild/android-x64@0.27.7':
     optional: true
 
-  '@esbuild/darwin-arm64@0.25.11':
+  '@esbuild/android-x64@0.28.1':
     optional: true
 
   '@esbuild/darwin-arm64@0.27.7':
     optional: true
 
-  '@esbuild/darwin-x64@0.25.11':
+  '@esbuild/darwin-arm64@0.28.1':
     optional: true
 
   '@esbuild/darwin-x64@0.27.7':
     optional: true
 
-  '@esbuild/freebsd-arm64@0.25.11':
+  '@esbuild/darwin-x64@0.28.1':
     optional: true
 
   '@esbuild/freebsd-arm64@0.27.7':
     optional: true
 
-  '@esbuild/freebsd-x64@0.25.11':
+  '@esbuild/freebsd-arm64@0.28.1':
     optional: true
 
   '@esbuild/freebsd-x64@0.27.7':
     optional: true
 
-  '@esbuild/linux-arm64@0.25.11':
+  '@esbuild/freebsd-x64@0.28.1':
     optional: true
 
   '@esbuild/linux-arm64@0.27.7':
     optional: true
 
-  '@esbuild/linux-arm@0.25.11':
+  '@esbuild/linux-arm64@0.28.1':
     optional: true
 
   '@esbuild/linux-arm@0.27.7':
     optional: true
 
-  '@esbuild/linux-ia32@0.25.11':
+  '@esbuild/linux-arm@0.28.1':
     optional: true
 
   '@esbuild/linux-ia32@0.27.7':
     optional: true
 
-  '@esbuild/linux-loong64@0.25.11':
+  '@esbuild/linux-ia32@0.28.1':
     optional: true
 
   '@esbuild/linux-loong64@0.27.7':
     optional: true
 
-  '@esbuild/linux-mips64el@0.25.11':
+  '@esbuild/linux-loong64@0.28.1':
     optional: true
 
   '@esbuild/linux-mips64el@0.27.7':
     optional: true
 
-  '@esbuild/linux-ppc64@0.25.11':
+  '@esbuild/linux-mips64el@0.28.1':
     optional: true
 
   '@esbuild/linux-ppc64@0.27.7':
     optional: true
 
-  '@esbuild/linux-riscv64@0.25.11':
+  '@esbuild/linux-ppc64@0.28.1':
     optional: true
 
   '@esbuild/linux-riscv64@0.27.7':
     optional: true
 
-  '@esbuild/linux-s390x@0.25.11':
+  '@esbuild/linux-riscv64@0.28.1':
     optional: true
 
   '@esbuild/linux-s390x@0.27.7':
     optional: true
 
-  '@esbuild/linux-x64@0.25.11':
+  '@esbuild/linux-s390x@0.28.1':
     optional: true
 
   '@esbuild/linux-x64@0.27.7':
     optional: true
 
-  '@esbuild/netbsd-arm64@0.25.11':
+  '@esbuild/linux-x64@0.28.1':
     optional: true
 
   '@esbuild/netbsd-arm64@0.27.7':
     optional: true
 
-  '@esbuild/netbsd-x64@0.25.11':
+  '@esbuild/netbsd-arm64@0.28.1':
     optional: true
 
   '@esbuild/netbsd-x64@0.27.7':
     optional: true
 
-  '@esbuild/openbsd-arm64@0.25.11':
+  '@esbuild/netbsd-x64@0.28.1':
     optional: true
 
   '@esbuild/openbsd-arm64@0.27.7':
     optional: true
 
-  '@esbuild/openbsd-x64@0.25.11':
+  '@esbuild/openbsd-arm64@0.28.1':
     optional: true
 
   '@esbuild/openbsd-x64@0.27.7':
     optional: true
 
-  '@esbuild/openharmony-arm64@0.25.11':
+  '@esbuild/openbsd-x64@0.28.1':
     optional: true
 
   '@esbuild/openharmony-arm64@0.27.7':
     optional: true
 
-  '@esbuild/sunos-x64@0.25.11':
+  '@esbuild/openharmony-arm64@0.28.1':
     optional: true
 
   '@esbuild/sunos-x64@0.27.7':
     optional: true
 
-  '@esbuild/win32-arm64@0.25.11':
+  '@esbuild/sunos-x64@0.28.1':
     optional: true
 
   '@esbuild/win32-arm64@0.27.7':
     optional: true
 
-  '@esbuild/win32-ia32@0.25.11':
+  '@esbuild/win32-arm64@0.28.1':
     optional: true
 
   '@esbuild/win32-ia32@0.27.7':
     optional: true
 
-  '@esbuild/win32-x64@0.25.11':
+  '@esbuild/win32-ia32@0.28.1':
     optional: true
 
   '@esbuild/win32-x64@0.27.7':
     optional: true
 
+  '@esbuild/win32-x64@0.28.1':
+    optional: true
+
   '@eslint-community/eslint-utils@4.9.1(eslint@10.0.0)':
     dependencies:
       eslint: 10.0.0
@@ -3062,7 +3068,7 @@ snapshots:
   '@stylistic/eslint-plugin-js@1.8.0(eslint@10.0.0)':
     dependencies:
       '@types/eslint': 8.56.12
-      acorn: 8.16.0
+      acorn: 8.17.0
       escape-string-regexp: 4.0.0
       eslint: 10.0.0
       eslint-visitor-keys: 3.4.3
@@ -3303,8 +3309,14 @@ snapshots:
     dependencies:
       acorn: 8.16.0
 
+  acorn-jsx@5.3.2(acorn@8.17.0):
+    dependencies:
+      acorn: 8.17.0
+
   acorn@8.16.0: {}
 
+  acorn@8.17.0: {}
+
   agent-base@7.1.1:
     dependencies:
       debug: 4.4.3
@@ -3475,7 +3487,7 @@ snapshots:
       ts-api-utils: 1.3.0(typescript@5.5.4)
       typescript: 5.5.4
 
-  enhanced-resolve@5.22.1:
+  enhanced-resolve@5.24.0:
     dependencies:
       graceful-fs: 4.2.11
       tapable: 2.3.3
@@ -3491,35 +3503,6 @@ snapshots:
 
   es-module-lexer@2.1.0: {}
 
-  esbuild@0.25.11:
-    optionalDependencies:
-      '@esbuild/aix-ppc64': 0.25.11
-      '@esbuild/android-arm': 0.25.11
-      '@esbuild/android-arm64': 0.25.11
-      '@esbuild/android-x64': 0.25.11
-      '@esbuild/darwin-arm64': 0.25.11
-      '@esbuild/darwin-x64': 0.25.11
-      '@esbuild/freebsd-arm64': 0.25.11
-      '@esbuild/freebsd-x64': 0.25.11
-      '@esbuild/linux-arm': 0.25.11
-      '@esbuild/linux-arm64': 0.25.11
-      '@esbuild/linux-ia32': 0.25.11
-      '@esbuild/linux-loong64': 0.25.11
-      '@esbuild/linux-mips64el': 0.25.11
-      '@esbuild/linux-ppc64': 0.25.11
-      '@esbuild/linux-riscv64': 0.25.11
-      '@esbuild/linux-s390x': 0.25.11
-      '@esbuild/linux-x64': 0.25.11
-      '@esbuild/netbsd-arm64': 0.25.11
-      '@esbuild/netbsd-x64': 0.25.11
-      '@esbuild/openbsd-arm64': 0.25.11
-      '@esbuild/openbsd-x64': 0.25.11
-      '@esbuild/openharmony-arm64': 0.25.11
-      '@esbuild/sunos-x64': 0.25.11
-      '@esbuild/win32-arm64': 0.25.11
-      '@esbuild/win32-ia32': 0.25.11
-      '@esbuild/win32-x64': 0.25.11
-
   esbuild@0.27.7:
     optionalDependencies:
       '@esbuild/aix-ppc64': 0.27.7
@@ -3549,12 +3532,41 @@ snapshots:
       '@esbuild/win32-ia32': 0.27.7
       '@esbuild/win32-x64': 0.27.7
 
+  esbuild@0.28.1:
+    optionalDependencies:
+      '@esbuild/aix-ppc64': 0.28.1
+      '@esbuild/android-arm': 0.28.1
+      '@esbuild/android-arm64': 0.28.1
+      '@esbuild/android-x64': 0.28.1
+      '@esbuild/darwin-arm64': 0.28.1
+      '@esbuild/darwin-x64': 0.28.1
+      '@esbuild/freebsd-arm64': 0.28.1
+      '@esbuild/freebsd-x64': 0.28.1
+      '@esbuild/linux-arm': 0.28.1
+      '@esbuild/linux-arm64': 0.28.1
+      '@esbuild/linux-ia32': 0.28.1
+      '@esbuild/linux-loong64': 0.28.1
+      '@esbuild/linux-mips64el': 0.28.1
+      '@esbuild/linux-ppc64': 0.28.1
+      '@esbuild/linux-riscv64': 0.28.1
+      '@esbuild/linux-s390x': 0.28.1
+      '@esbuild/linux-x64': 0.28.1
+      '@esbuild/netbsd-arm64': 0.28.1
+      '@esbuild/netbsd-x64': 0.28.1
+      '@esbuild/openbsd-arm64': 0.28.1
+      '@esbuild/openbsd-x64': 0.28.1
+      '@esbuild/openharmony-arm64': 0.28.1
+      '@esbuild/sunos-x64': 0.28.1
+      '@esbuild/win32-arm64': 0.28.1
+      '@esbuild/win32-ia32': 0.28.1
+      '@esbuild/win32-x64': 0.28.1
+
   escape-string-regexp@4.0.0: {}
 
   eslint-compat-utils@0.5.1(eslint@10.0.0):
     dependencies:
       eslint: 10.0.0
-      semver: 7.8.1
+      semver: 7.8.4
 
   eslint-config-prettier@9.1.0(eslint@10.0.0):
     dependencies:
@@ -3574,14 +3586,14 @@ snapshots:
   eslint-plugin-n@17.24.0(eslint@10.0.0)(typescript@5.5.4):
     dependencies:
       '@eslint-community/eslint-utils': 4.9.1(eslint@10.0.0)
-      enhanced-resolve: 5.22.1
+      enhanced-resolve: 5.24.0
       eslint: 10.0.0
       eslint-plugin-es-x: 7.8.0(eslint@10.0.0)
       get-tsconfig: 4.14.0
       globals: 15.15.0
       globrex: 0.1.2
       ignore: 5.3.2
-      semver: 7.8.1
+      semver: 7.8.4
       ts-declaration-location: 1.0.7(typescript@5.5.4)
     transitivePeerDependencies:
       - typescript
@@ -3673,8 +3685,8 @@ snapshots:
 
   espree@9.6.1:
     dependencies:
-      acorn: 8.16.0
-      acorn-jsx: 5.3.2(acorn@8.16.0)
+      acorn: 8.17.0
+      acorn-jsx: 5.3.2(acorn@8.17.0)
       eslint-visitor-keys: 3.4.3
 
   esprima@4.0.1: {}
@@ -4312,7 +4324,7 @@ snapshots:
 
   semver@7.7.4: {}
 
-  semver@7.8.1: {}
+  semver@7.8.4: {}
 
   serialize-javascript@6.0.2:
     dependencies:

From 0510174bc0c908c9d4980274717191fdf46a38c6 Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Mon, 15 Jun 2026 12:08:45 -0400
Subject: [PATCH 086/222] fix: make `SvelteURLSearchParams` notifications
 accurate (#18425)

`SvelteURLSearchParams` has two notification bugs that surface through
`SvelteURL`.

The first is over-notification. Setting `url.href` always rebuilds the
params and bumps their version signal, even when the search string
didn't change at all. Effects that read `size` (or any params method)
re-run on every unrelated `href` write, which is #17218, where it caused
infinite effect loops in a router. The fix is a guard in the internal
replace path that bails out when the incoming params serialize
identically to the current ones.

The second is under-notification, and it's sneakier. Every read method
tracks the version signal, `get`, `getAll`, `has`, `keys`, `values`,
`entries`, `toString`, `size`, the iterator... except `forEach`, which
was never overridden. The inherited platform method reads the internal
list directly and subscribes to nothing, so a template that renders
params via `forEach` never updates:

```js
$effect(() => {
	url.searchParams.forEach((value, key) => entries.push(`${key}=${value}`)); // never re-runs
});
```

We found this one in the wild while making `page.url` a `SvelteURL` in
sveltejs/kit#16031. Kit's own test suite renders query params with
`forEach`, and the coarse object-identity signal that previously masked
the gap went away, leaving stale UI after client-side navigations. The
fix is the same one-line tracking pattern every other read method
already uses.

Fixes #17218

---

- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).

### Tests and linting

- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
---
 .changeset/quick-meals-shout.md               |  5 ++
 .../src/reactivity/url-search-params.js       | 15 ++++
 .../src/reactivity/url-search-params.test.ts  | 21 ++++++
 packages/svelte/src/reactivity/url.test.ts    | 74 +++++++++++++++++++
 4 files changed, 115 insertions(+)
 create mode 100644 .changeset/quick-meals-shout.md

diff --git a/.changeset/quick-meals-shout.md b/.changeset/quick-meals-shout.md
new file mode 100644
index 0000000000..21871edd67
--- /dev/null
+++ b/.changeset/quick-meals-shout.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: don't notify `searchParams` subscribers when the URL changes without affecting the search string
diff --git a/packages/svelte/src/reactivity/url-search-params.js b/packages/svelte/src/reactivity/url-search-params.js
index 38cf3ebe4f..d745bb6b08 100644
--- a/packages/svelte/src/reactivity/url-search-params.js
+++ b/packages/svelte/src/reactivity/url-search-params.js
@@ -54,6 +54,11 @@ export class SvelteURLSearchParams extends URLSearchParams {
 	 */
 	[REPLACE](params) {
 		if (this.#updating) return;
+
+		// the URL may have changed in a way that leaves the search string untouched —
+		// don't rebuild the params or notify readers if nothing changed
+		if (params.toString() === super.toString()) return;
+
 		this.#updating = true;
 
 		for (const key of [...super.keys()]) {
@@ -126,6 +131,16 @@ export class SvelteURLSearchParams extends URLSearchParams {
 		return super.keys();
 	}
 
+	/**
+	 * @param {(value: string, key: string, parent: URLSearchParams) => void} callback
+	 * @param {any} [this_arg]
+	 * @returns {void}
+	 */
+	forEach(callback, this_arg) {
+		get(this.#version);
+		super.forEach(callback, this_arg);
+	}
+
 	/**
 	 * @param {string} name
 	 * @param {string} value
diff --git a/packages/svelte/src/reactivity/url-search-params.test.ts b/packages/svelte/src/reactivity/url-search-params.test.ts
index b0c84872b0..765b4020f3 100644
--- a/packages/svelte/src/reactivity/url-search-params.test.ts
+++ b/packages/svelte/src/reactivity/url-search-params.test.ts
@@ -244,3 +244,24 @@ test('URLSearchParams.toString', () => {
 test('SvelteURLSearchParams instanceof URLSearchParams', () => {
 	assert.ok(new SvelteURLSearchParams() instanceof URLSearchParams);
 });
+
+test('params.forEach is reactive', () => {
+	const params = new SvelteURLSearchParams('foo=1');
+	const log: any = [];
+
+	const cleanup = effect_root(() => {
+		render_effect(() => {
+			const entries: string[] = [];
+			params.forEach((value, key) => entries.push(`${key}=${value}`));
+			log.push(entries.join('&'));
+		});
+	});
+
+	flushSync(() => {
+		params.set('foo', '2');
+	});
+
+	assert.deepEqual(log, ['foo=1', 'foo=2']);
+
+	cleanup();
+});
diff --git a/packages/svelte/src/reactivity/url.test.ts b/packages/svelte/src/reactivity/url.test.ts
index a79aa32315..d698116421 100644
--- a/packages/svelte/src/reactivity/url.test.ts
+++ b/packages/svelte/src/reactivity/url.test.ts
@@ -166,3 +166,77 @@ test('url.search normalizes value', () => {
 test('SvelteURL instanceof URL', () => {
 	assert.ok(new SvelteURL('https://svelte.dev') instanceof URL);
 });
+
+test('url.searchParams subscribers are not notified by changes that leave the search string untouched', () => {
+	const url = new SvelteURL('https://svelte.dev/a?foo=bar');
+	const log: any = [];
+
+	const cleanup = effect_root(() => {
+		render_effect(() => {
+			log.push(url.searchParams.toString());
+		});
+	});
+
+	flushSync(() => {
+		// does not affect the search string
+		url.pathname = '/b';
+	});
+
+	flushSync(() => {
+		// neither does this
+		url.href = 'https://svelte.dev/c?foo=bar#hash';
+	});
+
+	flushSync(() => {
+		// but this does
+		url.search = '?foo=baz';
+	});
+
+	assert.deepEqual(log, ['foo=bar', 'foo=baz']);
+
+	cleanup();
+});
+
+test('url.searchParams.size is not notified by unrelated href changes', () => {
+	const url = new SvelteURL('https://svelte.dev/?foo=bar');
+	const log: any = [];
+
+	const cleanup = effect_root(() => {
+		render_effect(() => {
+			log.push(url.searchParams.size);
+		});
+	});
+
+	flushSync(() => {
+		url.href = 'https://svelte.dev/other?foo=bar';
+	});
+
+	flushSync(() => {
+		url.searchParams.append('baz', 'qux');
+	});
+
+	assert.deepEqual(log, [1, 2]);
+
+	cleanup();
+});
+
+test('url.searchParams.forEach re-runs when the search string changes via the URL', () => {
+	const url = new SvelteURL('https://svelte.dev/?foo=1');
+	const log: any = [];
+
+	const cleanup = effect_root(() => {
+		render_effect(() => {
+			const entries: string[] = [];
+			url.searchParams.forEach((value, key) => entries.push(`${key}=${value}`));
+			log.push(entries.join('&'));
+		});
+	});
+
+	flushSync(() => {
+		url.href = 'https://svelte.dev/?bar=2';
+	});
+
+	assert.deepEqual(log, ['foo=1', 'bar=2']);
+
+	cleanup();
+});

From c4daa490bbbf483ebba117c1afb6f71b4b19e63c Mon Sep 17 00:00:00 2001
From: Yuichiro Yamashita <xydybaseball@gmail.com>
Date: Tue, 16 Jun 2026 01:18:02 +0900
Subject: [PATCH 087/222] fix: include wrapping parentheses in `{@const}`
 declarator end (#18436)

`{@const x = (a)}` (and any `{@const}` whose initializer is wrapped in
parentheses, e.g. `(a = b)`, `({ ... })`) produced a
`VariableDeclarator` whose `end` fell before the closing `)`.
`read_expression` strips the wrapping parens from the returned node but
advances the parser past them, so `init.end` excludes the `)` while the
parser position does not. Use the parser position for the declarator
`end` instead. Fixes source slices / tooling that rely on the node range
(the range previously yielded invalid, unbalanced source).

<img width="2064" height="1746" alt="image"
src="https://github.com/user-attachments/assets/64153ee5-d543-442d-8018-d3668acfd7a7"
/>


### Before submitting the PR, please make sure you do the following

- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).

### Tests and linting

- [ ] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
---
 .changeset/clean-melons-attack.md             |   5 +
 .../src/compiler/phases/1-parse/state/tag.js  |   6 +-
 .../const-tag-parenthesized-init/input.svelte |   6 +
 .../const-tag-parenthesized-init/output.json  | 527 ++++++++++++++++++
 4 files changed, 543 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/clean-melons-attack.md
 create mode 100644 packages/svelte/tests/parser-modern/samples/const-tag-parenthesized-init/input.svelte
 create mode 100644 packages/svelte/tests/parser-modern/samples/const-tag-parenthesized-init/output.json

diff --git a/.changeset/clean-melons-attack.md b/.changeset/clean-melons-attack.md
new file mode 100644
index 0000000000..8b5a9f2066
--- /dev/null
+++ b/.changeset/clean-melons-attack.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: include wrapping parentheses in `{@const}` declarator `end` position
diff --git a/packages/svelte/src/compiler/phases/1-parse/state/tag.js b/packages/svelte/src/compiler/phases/1-parse/state/tag.js
index 15c79e0353..f5314d04ed 100644
--- a/packages/svelte/src/compiler/phases/1-parse/state/tag.js
+++ b/packages/svelte/src/compiler/phases/1-parse/state/tag.js
@@ -783,6 +783,8 @@ function special(parser) {
 
 		const expression_start = parser.index;
 		const init = read_expression(parser);
+		// parser is past wrapping parens, but `init.end` is not — use the parser position
+		const declarator_end = parser.index;
 		if (
 			init.type === 'SequenceExpression' &&
 			!parser.template.substring(expression_start, init.start).includes('(')
@@ -801,7 +803,9 @@ function special(parser) {
 			declaration: {
 				type: 'VariableDeclaration',
 				kind: 'const',
-				declarations: [{ type: 'VariableDeclarator', id, init, start: id.start, end: init.end }],
+				declarations: [
+					{ type: 'VariableDeclarator', id, init, start: id.start, end: declarator_end }
+				],
 				start: start + 2, // start at const, not at @const
 				end: parser.index - 1
 			},
diff --git a/packages/svelte/tests/parser-modern/samples/const-tag-parenthesized-init/input.svelte b/packages/svelte/tests/parser-modern/samples/const-tag-parenthesized-init/input.svelte
new file mode 100644
index 0000000000..39bf04093e
--- /dev/null
+++ b/packages/svelte/tests/parser-modern/samples/const-tag-parenthesized-init/input.svelte
@@ -0,0 +1,6 @@
+{#each items as item}
+	{@const x = (item.value)}
+	{@const y = (a = item.n)}
+	{@const z = ({ a: item.a })}
+	{x}{y}{z.a}
+{/each}
diff --git a/packages/svelte/tests/parser-modern/samples/const-tag-parenthesized-init/output.json b/packages/svelte/tests/parser-modern/samples/const-tag-parenthesized-init/output.json
new file mode 100644
index 0000000000..3e8d8b23d5
--- /dev/null
+++ b/packages/svelte/tests/parser-modern/samples/const-tag-parenthesized-init/output.json
@@ -0,0 +1,527 @@
+{
+	"css": null,
+	"js": [],
+	"start": 0,
+	"end": 126,
+	"type": "Root",
+	"fragment": {
+		"type": "Fragment",
+		"nodes": [
+			{
+				"type": "EachBlock",
+				"start": 0,
+				"end": 126,
+				"expression": {
+					"type": "Identifier",
+					"start": 7,
+					"end": 12,
+					"loc": {
+						"start": {
+							"line": 1,
+							"column": 7
+						},
+						"end": {
+							"line": 1,
+							"column": 12
+						}
+					},
+					"name": "items"
+				},
+				"body": {
+					"type": "Fragment",
+					"nodes": [
+						{
+							"type": "Text",
+							"start": 21,
+							"end": 23,
+							"raw": "\n\t",
+							"data": "\n\t"
+						},
+						{
+							"type": "ConstTag",
+							"start": 23,
+							"end": 48,
+							"declaration": {
+								"type": "VariableDeclaration",
+								"kind": "const",
+								"declarations": [
+									{
+										"type": "VariableDeclarator",
+										"id": {
+											"type": "Identifier",
+											"name": "x",
+											"start": 31,
+											"end": 32,
+											"loc": {
+												"start": {
+													"line": 2,
+													"column": 9,
+													"character": 31
+												},
+												"end": {
+													"line": 2,
+													"column": 10,
+													"character": 32
+												}
+											}
+										},
+										"init": {
+											"type": "MemberExpression",
+											"start": 36,
+											"end": 46,
+											"loc": {
+												"start": {
+													"line": 2,
+													"column": 14
+												},
+												"end": {
+													"line": 2,
+													"column": 24
+												}
+											},
+											"object": {
+												"type": "Identifier",
+												"start": 36,
+												"end": 40,
+												"loc": {
+													"start": {
+														"line": 2,
+														"column": 14
+													},
+													"end": {
+														"line": 2,
+														"column": 18
+													}
+												},
+												"name": "item"
+											},
+											"property": {
+												"type": "Identifier",
+												"start": 41,
+												"end": 46,
+												"loc": {
+													"start": {
+														"line": 2,
+														"column": 19
+													},
+													"end": {
+														"line": 2,
+														"column": 24
+													}
+												},
+												"name": "value"
+											},
+											"computed": false,
+											"optional": false
+										},
+										"start": 31,
+										"end": 47
+									}
+								],
+								"start": 25,
+								"end": 47
+							}
+						},
+						{
+							"type": "Text",
+							"start": 48,
+							"end": 50,
+							"raw": "\n\t",
+							"data": "\n\t"
+						},
+						{
+							"type": "ConstTag",
+							"start": 50,
+							"end": 75,
+							"declaration": {
+								"type": "VariableDeclaration",
+								"kind": "const",
+								"declarations": [
+									{
+										"type": "VariableDeclarator",
+										"id": {
+											"type": "Identifier",
+											"name": "y",
+											"start": 58,
+											"end": 59,
+											"loc": {
+												"start": {
+													"line": 3,
+													"column": 9,
+													"character": 58
+												},
+												"end": {
+													"line": 3,
+													"column": 10,
+													"character": 59
+												}
+											}
+										},
+										"init": {
+											"type": "AssignmentExpression",
+											"start": 63,
+											"end": 73,
+											"loc": {
+												"start": {
+													"line": 3,
+													"column": 14
+												},
+												"end": {
+													"line": 3,
+													"column": 24
+												}
+											},
+											"operator": "=",
+											"left": {
+												"type": "Identifier",
+												"start": 63,
+												"end": 64,
+												"loc": {
+													"start": {
+														"line": 3,
+														"column": 14
+													},
+													"end": {
+														"line": 3,
+														"column": 15
+													}
+												},
+												"name": "a"
+											},
+											"right": {
+												"type": "MemberExpression",
+												"start": 67,
+												"end": 73,
+												"loc": {
+													"start": {
+														"line": 3,
+														"column": 18
+													},
+													"end": {
+														"line": 3,
+														"column": 24
+													}
+												},
+												"object": {
+													"type": "Identifier",
+													"start": 67,
+													"end": 71,
+													"loc": {
+														"start": {
+															"line": 3,
+															"column": 18
+														},
+														"end": {
+															"line": 3,
+															"column": 22
+														}
+													},
+													"name": "item"
+												},
+												"property": {
+													"type": "Identifier",
+													"start": 72,
+													"end": 73,
+													"loc": {
+														"start": {
+															"line": 3,
+															"column": 23
+														},
+														"end": {
+															"line": 3,
+															"column": 24
+														}
+													},
+													"name": "n"
+												},
+												"computed": false,
+												"optional": false
+											}
+										},
+										"start": 58,
+										"end": 74
+									}
+								],
+								"start": 52,
+								"end": 74
+							}
+						},
+						{
+							"type": "Text",
+							"start": 75,
+							"end": 77,
+							"raw": "\n\t",
+							"data": "\n\t"
+						},
+						{
+							"type": "ConstTag",
+							"start": 77,
+							"end": 105,
+							"declaration": {
+								"type": "VariableDeclaration",
+								"kind": "const",
+								"declarations": [
+									{
+										"type": "VariableDeclarator",
+										"id": {
+											"type": "Identifier",
+											"name": "z",
+											"start": 85,
+											"end": 86,
+											"loc": {
+												"start": {
+													"line": 4,
+													"column": 9,
+													"character": 85
+												},
+												"end": {
+													"line": 4,
+													"column": 10,
+													"character": 86
+												}
+											}
+										},
+										"init": {
+											"type": "ObjectExpression",
+											"start": 90,
+											"end": 103,
+											"loc": {
+												"start": {
+													"line": 4,
+													"column": 14
+												},
+												"end": {
+													"line": 4,
+													"column": 27
+												}
+											},
+											"properties": [
+												{
+													"type": "Property",
+													"start": 92,
+													"end": 101,
+													"loc": {
+														"start": {
+															"line": 4,
+															"column": 16
+														},
+														"end": {
+															"line": 4,
+															"column": 25
+														}
+													},
+													"method": false,
+													"shorthand": false,
+													"computed": false,
+													"key": {
+														"type": "Identifier",
+														"start": 92,
+														"end": 93,
+														"loc": {
+															"start": {
+																"line": 4,
+																"column": 16
+															},
+															"end": {
+																"line": 4,
+																"column": 17
+															}
+														},
+														"name": "a"
+													},
+													"value": {
+														"type": "MemberExpression",
+														"start": 95,
+														"end": 101,
+														"loc": {
+															"start": {
+																"line": 4,
+																"column": 19
+															},
+															"end": {
+																"line": 4,
+																"column": 25
+															}
+														},
+														"object": {
+															"type": "Identifier",
+															"start": 95,
+															"end": 99,
+															"loc": {
+																"start": {
+																	"line": 4,
+																	"column": 19
+																},
+																"end": {
+																	"line": 4,
+																	"column": 23
+																}
+															},
+															"name": "item"
+														},
+														"property": {
+															"type": "Identifier",
+															"start": 100,
+															"end": 101,
+															"loc": {
+																"start": {
+																	"line": 4,
+																	"column": 24
+																},
+																"end": {
+																	"line": 4,
+																	"column": 25
+																}
+															},
+															"name": "a"
+														},
+														"computed": false,
+														"optional": false
+													},
+													"kind": "init"
+												}
+											]
+										},
+										"start": 85,
+										"end": 104
+									}
+								],
+								"start": 79,
+								"end": 104
+							}
+						},
+						{
+							"type": "Text",
+							"start": 105,
+							"end": 107,
+							"raw": "\n\t",
+							"data": "\n\t"
+						},
+						{
+							"type": "ExpressionTag",
+							"start": 107,
+							"end": 110,
+							"expression": {
+								"type": "Identifier",
+								"start": 108,
+								"end": 109,
+								"loc": {
+									"start": {
+										"line": 5,
+										"column": 2
+									},
+									"end": {
+										"line": 5,
+										"column": 3
+									}
+								},
+								"name": "x"
+							}
+						},
+						{
+							"type": "ExpressionTag",
+							"start": 110,
+							"end": 113,
+							"expression": {
+								"type": "Identifier",
+								"start": 111,
+								"end": 112,
+								"loc": {
+									"start": {
+										"line": 5,
+										"column": 5
+									},
+									"end": {
+										"line": 5,
+										"column": 6
+									}
+								},
+								"name": "y"
+							}
+						},
+						{
+							"type": "ExpressionTag",
+							"start": 113,
+							"end": 118,
+							"expression": {
+								"type": "MemberExpression",
+								"start": 114,
+								"end": 117,
+								"loc": {
+									"start": {
+										"line": 5,
+										"column": 8
+									},
+									"end": {
+										"line": 5,
+										"column": 11
+									}
+								},
+								"object": {
+									"type": "Identifier",
+									"start": 114,
+									"end": 115,
+									"loc": {
+										"start": {
+											"line": 5,
+											"column": 8
+										},
+										"end": {
+											"line": 5,
+											"column": 9
+										}
+									},
+									"name": "z"
+								},
+								"property": {
+									"type": "Identifier",
+									"start": 116,
+									"end": 117,
+									"loc": {
+										"start": {
+											"line": 5,
+											"column": 10
+										},
+										"end": {
+											"line": 5,
+											"column": 11
+										}
+									},
+									"name": "a"
+								},
+								"computed": false,
+								"optional": false
+							}
+						},
+						{
+							"type": "Text",
+							"start": 118,
+							"end": 119,
+							"raw": "\n",
+							"data": "\n"
+						}
+					]
+				},
+				"context": {
+					"type": "Identifier",
+					"name": "item",
+					"start": 16,
+					"end": 20,
+					"loc": {
+						"start": {
+							"line": 1,
+							"column": 16,
+							"character": 16
+						},
+						"end": {
+							"line": 1,
+							"column": 20,
+							"character": 20
+						}
+					}
+				}
+			}
+		]
+	},
+	"options": null
+}

From a6985bcd24faa8ec4a8de671b2013d98b0bc629f Mon Sep 17 00:00:00 2001
From: "jyc.dev" <jycouet@gmail.com>
Date: Mon, 22 Jun 2026 13:03:18 +0200
Subject: [PATCH 088/222] fix: strip `?` from optional parameters in svelte
 lang ts (#18448)

In `esrap@2.2.12` we fixed the missing `?` in ts files
https://github.com/sveltejs/esrap/pull/139
It's good for `ts`, but bad for svelte compiler that was not removing it
as it was a esrap issue not printing it :/

This issue came: https://github.com/sveltejs/esrap/issues/141

This PR is fixing the issue in the compiler stripping the `?`
---
 .changeset/strip-optional-param-marker.md     |  5 +++++
 packages/svelte/package.json                  |  2 +-
 .../phases/1-parse/remove_typescript_nodes.js |  6 +++++
 .../_expected/client/index.svelte.js          | 22 +++++++++++++++++++
 .../_expected/server/index.svelte.js          | 15 +++++++++++++
 .../index.svelte                              | 14 ++++++++++++
 pnpm-lock.yaml                                | 12 +++++-----
 7 files changed, 69 insertions(+), 7 deletions(-)
 create mode 100644 .changeset/strip-optional-param-marker.md
 create mode 100644 packages/svelte/tests/snapshot/samples/typescript-optional-parameter/_expected/client/index.svelte.js
 create mode 100644 packages/svelte/tests/snapshot/samples/typescript-optional-parameter/_expected/server/index.svelte.js
 create mode 100644 packages/svelte/tests/snapshot/samples/typescript-optional-parameter/index.svelte

diff --git a/.changeset/strip-optional-param-marker.md b/.changeset/strip-optional-param-marker.md
new file mode 100644
index 0000000000..a6b759747c
--- /dev/null
+++ b/.changeset/strip-optional-param-marker.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: strip `?` from optional parameters in `<script lang="ts">` so generated JavaScript is valid
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index eeca8e032e..c1b9f44e36 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -181,7 +181,7 @@
     "clsx": "^2.1.1",
     "devalue": "^5.8.1",
     "esm-env": "^1.2.1",
-    "esrap": "^2.2.11",
+    "esrap": "^2.2.12",
     "is-reference": "^3.0.3",
     "locate-character": "^3.0.0",
     "magic-string": "^0.30.11",
diff --git a/packages/svelte/src/compiler/phases/1-parse/remove_typescript_nodes.js b/packages/svelte/src/compiler/phases/1-parse/remove_typescript_nodes.js
index 438d6fe48f..f573147367 100644
--- a/packages/svelte/src/compiler/phases/1-parse/remove_typescript_nodes.js
+++ b/packages/svelte/src/compiler/phases/1-parse/remove_typescript_nodes.js
@@ -30,6 +30,12 @@ const visitors = {
 		delete n.readonly;
 		delete n.definite;
 		delete n.override;
+
+		// `optional` is reused by JS optional chaining (`a?.b`, `a?.()`), so only
+		// strip the TypeScript optional marker (`x?: T`, `m?(): T`, `x?: T` fields)
+		if (n.type !== 'MemberExpression' && n.type !== 'CallExpression') {
+			delete n.optional;
+		}
 	},
 	Decorator(node) {
 		e.typescript_invalid_feature(node, 'decorators (related TSC proposal is not stage 4 yet)');
diff --git a/packages/svelte/tests/snapshot/samples/typescript-optional-parameter/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/typescript-optional-parameter/_expected/client/index.svelte.js
new file mode 100644
index 0000000000..3593b6c65e
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/typescript-optional-parameter/_expected/client/index.svelte.js
@@ -0,0 +1,22 @@
+import 'svelte/internal/disclose-version';
+import 'svelte/internal/flags/legacy';
+import * as $ from 'svelte/internal/client';
+
+export default function Typescript_optional_parameter($$anchor) {
+	// the `?` on the optional parameter must be stripped, but optional chaining
+	// (`x?.length`, `o?.b`) must be preserved
+	function a(x) {
+		return x?.length;
+	}
+
+	const o = {};
+	const v = o?.b?.c;
+
+	a();
+	$.next();
+
+	var text = $.text();
+
+	$.template_effect(() => $.set_text(text, v));
+	$.append($$anchor, text);
+}
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/typescript-optional-parameter/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/typescript-optional-parameter/_expected/server/index.svelte.js
new file mode 100644
index 0000000000..d6c5e271f0
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/typescript-optional-parameter/_expected/server/index.svelte.js
@@ -0,0 +1,15 @@
+import * as $ from 'svelte/internal/server';
+
+export default function Typescript_optional_parameter($$renderer) {
+	// the `?` on the optional parameter must be stripped, but optional chaining
+	// (`x?.length`, `o?.b`) must be preserved
+	function a(x) {
+		return x?.length;
+	}
+
+	const o = {};
+	const v = o?.b?.c;
+
+	a();
+	$$renderer.push(`<!---->${$.escape(v)}`);
+}
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/typescript-optional-parameter/index.svelte b/packages/svelte/tests/snapshot/samples/typescript-optional-parameter/index.svelte
new file mode 100644
index 0000000000..f6bcb53e47
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/typescript-optional-parameter/index.svelte
@@ -0,0 +1,14 @@
+<script lang="ts">
+	// the `?` on the optional parameter must be stripped, but optional chaining
+	// (`x?.length`, `o?.b`) must be preserved
+	function a(x?: string) {
+		return x?.length;
+	}
+
+	const o: { b?: { c: number } } = {};
+	const v = o?.b?.c;
+
+	a();
+</script>
+
+{v}
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index e86c927efe..6331fd0789 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -102,8 +102,8 @@ importers:
         specifier: ^1.2.1
         version: 1.2.1
       esrap:
-        specifier: ^2.2.11
-        version: 2.2.11(@typescript-eslint/types@8.59.4)
+        specifier: ^2.2.12
+        version: 2.2.12(@typescript-eslint/types@8.59.4)
       is-reference:
         specifier: ^3.0.3
         version: 3.0.3
@@ -1418,8 +1418,8 @@ packages:
     resolution: {integrity: sha512-Ap6G0WQwcU/LHsvLwON1fAQX9Zp0A2Y6Y/cJBl9r/JbW90Zyg4/zbG6zzKa2OTALELarYHmKu0GhpM5EO+7T0g==}
     engines: {node: '>=0.10'}
 
-  esrap@2.2.11:
-    resolution: {integrity: sha512-gPdx+I+BjYEinNMQaBXFjbaJVyoPMU4ZODg5mE+M4DqVG9VusAVHHjcBX+zqyITlI0DIARwDMMzZwAWj36dRoQ==}
+  esrap@2.2.12:
+    resolution: {integrity: sha512-On0QbLyaiAkVC4eXtgnXK9Kh2opit+3rcUSOc45DqJ2s/X2eXAHsGOKRSJ6IDagQEW5vPyivANfXUiqgXC67Rw==}
     peerDependencies:
       '@typescript-eslint/types': ^8.2.0
     peerDependenciesMeta:
@@ -2886,7 +2886,7 @@ snapshots:
   '@jridgewell/gen-mapping@0.3.5':
     dependencies:
       '@jridgewell/set-array': 1.2.1
-      '@jridgewell/sourcemap-codec': 1.5.0
+      '@jridgewell/sourcemap-codec': 1.5.5
       '@jridgewell/trace-mapping': 0.3.31
 
   '@jridgewell/remapping@2.3.4':
@@ -3695,7 +3695,7 @@ snapshots:
     dependencies:
       estraverse: 5.3.0
 
-  esrap@2.2.11(@typescript-eslint/types@8.59.4):
+  esrap@2.2.12(@typescript-eslint/types@8.59.4):
     dependencies:
       '@jridgewell/sourcemap-codec': 1.5.5
     optionalDependencies:

From 36ae0622a8da4c6e60d32cde199af3d7c3121cd3 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Mon, 22 Jun 2026 20:09:04 +0200
Subject: [PATCH 089/222] fix: always unset reactivity context after restoring
 it (#18453)

When calling `save`, we restore the context after the promise resolves.
But we do not unset it after the subsequent synchronous execution. That
means that until `unset_context` runs in `async_derived` we will not
have the correct (nulled) context. That causes problems if the `save`
isn't the last promise contributing to the `async_derived`, because it
means the context is not properly unset until the promise _after_ the
`save` within the `async_derived` settles. This can cause all sorts of
mixups, including a wrong mutation error.

fixes #18441
---
 .changeset/late-geese-fix.md                  |  5 +++
 .../src/internal/client/reactivity/async.js   |  2 +
 .../_config.js                                | 44 +++++++++++++++++++
 .../main.svelte                               | 28 ++++++++++++
 4 files changed, 79 insertions(+)
 create mode 100644 .changeset/late-geese-fix.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-parallel-derived-template-mutation/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-parallel-derived-template-mutation/main.svelte

diff --git a/.changeset/late-geese-fix.md b/.changeset/late-geese-fix.md
new file mode 100644
index 0000000000..b8e83fc8cd
--- /dev/null
+++ b/.changeset/late-geese-fix.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: always unset reactivity context after restoring it
diff --git a/packages/svelte/src/internal/client/reactivity/async.js b/packages/svelte/src/internal/client/reactivity/async.js
index 13b6e42b3e..2e7df92dc0 100644
--- a/packages/svelte/src/internal/client/reactivity/async.js
+++ b/packages/svelte/src/internal/client/reactivity/async.js
@@ -25,6 +25,7 @@ import {
 	set_reactivity_loss_tracker
 } from './deriveds.js';
 import { aborted } from './effects.js';
+import { queue_micro_task } from '../dom/task.js';
 
 /**
  * @param {Blocker[]} blockers
@@ -169,6 +170,7 @@ export async function save(promise) {
 
 	return () => {
 		restore();
+		queue_micro_task(unset_context);
 		return value;
 	};
 }
diff --git a/packages/svelte/tests/runtime-runes/samples/async-parallel-derived-template-mutation/_config.js b/packages/svelte/tests/runtime-runes/samples/async-parallel-derived-template-mutation/_config.js
new file mode 100644
index 0000000000..9650e88993
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-parallel-derived-template-mutation/_config.js
@@ -0,0 +1,44 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['client'],
+
+	compileOptions: {
+		dev: true
+	},
+
+	async test({ assert, target, errors }) {
+		await tick();
+		const [increment, update, resolve] = target.querySelectorAll('button');
+
+		increment.click();
+		await tick();
+
+		resolve.click();
+		await tick();
+
+		update.click();
+		await tick();
+
+		resolve.click();
+		await tick();
+
+		assert.deepEqual(
+			errors.filter((error) => error.includes('state_unsafe_mutation')),
+			[]
+		);
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>increment</button>
+				<button>update</button>
+				<button>resolve</button>
+				<p>count: 1</p>	
+				<p>submits: 1</p>	
+				<p>pending: 0</p>	
+				<p>2</p>	
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-parallel-derived-template-mutation/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-parallel-derived-template-mutation/main.svelte
new file mode 100644
index 0000000000..d9c804b314
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-parallel-derived-template-mutation/main.svelte
@@ -0,0 +1,28 @@
+<script>
+	const queued = [];
+
+	function push(value) {
+		if(!value) return value;
+		return new Promise((resolve) => queued.push(() => resolve(value)));
+	}
+
+	let count = $state(0);
+	let submits = $state(0);
+
+	const a = $derived(push(count));
+	const b = $derived(push(count));
+
+	async function updateAfterPromise() {
+		await Promise.resolve(); 
+		submits += 1;
+	}
+</script>
+
+<button onclick={() => (count += 1)}>increment</button>
+<button onclick={updateAfterPromise}>update</button>
+<button onclick={() => queued.shift()?.()}>resolve</button>
+
+<p>count: {count}</p>
+<p>submits: {submits}</p>
+<p>pending: {$effect.pending()}</p>
+<p>{await a + await b}</p>

From eae50dfd1c2269e37258ef5c09527003bcf61573 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Tue, 23 Jun 2026 14:44:52 -0400
Subject: [PATCH 090/222] Version Packages (#18435)

This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.


# Releases
## svelte@5.56.4

### Patch Changes

- fix: include wrapping parentheses in `{@const}` declarator `end`
position ([#18436](https://github.com/sveltejs/svelte/pull/18436))

- fix: always unset reactivity context after restoring it
([#18453](https://github.com/sveltejs/svelte/pull/18453))

- fix: don't notify `searchParams` subscribers when the URL changes
without affecting the search string
([#18425](https://github.com/sveltejs/svelte/pull/18425))

- fix: strip `?` from optional parameters in `<script lang="ts">` so
generated JavaScript is valid
([#18448](https://github.com/sveltejs/svelte/pull/18448))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/clean-melons-attack.md         |  5 -----
 .changeset/late-geese-fix.md              |  5 -----
 .changeset/quick-meals-shout.md           |  5 -----
 .changeset/strip-optional-param-marker.md |  5 -----
 packages/svelte/CHANGELOG.md              | 12 ++++++++++++
 packages/svelte/package.json              |  2 +-
 packages/svelte/src/version.js            |  2 +-
 7 files changed, 14 insertions(+), 22 deletions(-)
 delete mode 100644 .changeset/clean-melons-attack.md
 delete mode 100644 .changeset/late-geese-fix.md
 delete mode 100644 .changeset/quick-meals-shout.md
 delete mode 100644 .changeset/strip-optional-param-marker.md

diff --git a/.changeset/clean-melons-attack.md b/.changeset/clean-melons-attack.md
deleted file mode 100644
index 8b5a9f2066..0000000000
--- a/.changeset/clean-melons-attack.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: include wrapping parentheses in `{@const}` declarator `end` position
diff --git a/.changeset/late-geese-fix.md b/.changeset/late-geese-fix.md
deleted file mode 100644
index b8e83fc8cd..0000000000
--- a/.changeset/late-geese-fix.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: always unset reactivity context after restoring it
diff --git a/.changeset/quick-meals-shout.md b/.changeset/quick-meals-shout.md
deleted file mode 100644
index 21871edd67..0000000000
--- a/.changeset/quick-meals-shout.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: don't notify `searchParams` subscribers when the URL changes without affecting the search string
diff --git a/.changeset/strip-optional-param-marker.md b/.changeset/strip-optional-param-marker.md
deleted file mode 100644
index a6b759747c..0000000000
--- a/.changeset/strip-optional-param-marker.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: strip `?` from optional parameters in `<script lang="ts">` so generated JavaScript is valid
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 02dd84ddff..80b61facb0 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,17 @@
 # svelte
 
+## 5.56.4
+
+### Patch Changes
+
+- fix: include wrapping parentheses in `{@const}` declarator `end` position ([#18436](https://github.com/sveltejs/svelte/pull/18436))
+
+- fix: always unset reactivity context after restoring it ([#18453](https://github.com/sveltejs/svelte/pull/18453))
+
+- fix: don't notify `searchParams` subscribers when the URL changes without affecting the search string ([#18425](https://github.com/sveltejs/svelte/pull/18425))
+
+- fix: strip `?` from optional parameters in `<script lang="ts">` so generated JavaScript is valid ([#18448](https://github.com/sveltejs/svelte/pull/18448))
+
 ## 5.56.3
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index c1b9f44e36..34fa68c8a7 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.56.3",
+  "version": "5.56.4",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index b6d4236ff8..ef468a2f79 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.56.3';
+export const VERSION = '5.56.4';
 export const PUBLIC_VERSION = '5';

From b9e03714ebe1dbad9b31351f4e2d5487c90c670a Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Thu, 2 Jul 2026 08:30:23 +0200
Subject: [PATCH 091/222] fix: correctly transform declaration tags during SSR
 (#18492)

Closes #18490
---
 .changeset/rich-jokes-attack.md                             | 5 +++++
 .../phases/3-transform/server/visitors/shared/utils.js      | 6 ++++--
 .../samples/declaration-tags-transform/_expected.html       | 1 +
 .../samples/declaration-tags-transform/main.svelte          | 4 ++++
 4 files changed, 14 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/rich-jokes-attack.md
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/declaration-tags-transform/_expected.html
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/declaration-tags-transform/main.svelte

diff --git a/.changeset/rich-jokes-attack.md b/.changeset/rich-jokes-attack.md
new file mode 100644
index 0000000000..46e7d2d8c8
--- /dev/null
+++ b/.changeset/rich-jokes-attack.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: correctly transform declaration tags during SSR
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
index 3da6fcf321..56157cee37 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
@@ -60,7 +60,9 @@ export function process_children(nodes, { visit, state }) {
 				if (evaluated.is_known) {
 					quasi.value.cooked += escape_html((evaluated.value ?? '') + '');
 				} else {
-					expressions.push(b.call('$.escape', /** @type {Expression} */ (visit(node.expression))));
+					expressions.push(
+						b.call('$.escape', /** @type {Expression} */ (visit(node.expression, state)))
+					);
 
 					quasi = b.quasi('', i + 1 === sequence.length);
 					quasis.push(quasi);
@@ -80,7 +82,7 @@ export function process_children(nodes, { visit, state }) {
 		if (node.type === 'ExpressionTag' && node.metadata.expression.is_async()) {
 			flush();
 
-			const expression = /** @type {Expression} */ (visit(node.expression));
+			const expression = /** @type {Expression} */ (visit(node.expression, state));
 
 			let call = b.call(
 				'$$renderer.push',
diff --git a/packages/svelte/tests/server-side-rendering/samples/declaration-tags-transform/_expected.html b/packages/svelte/tests/server-side-rendering/samples/declaration-tags-transform/_expected.html
new file mode 100644
index 0000000000..5665318328
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/declaration-tags-transform/_expected.html
@@ -0,0 +1 @@
+<!--[--><div>number</div><!--]-->
\ No newline at end of file
diff --git a/packages/svelte/tests/server-side-rendering/samples/declaration-tags-transform/main.svelte b/packages/svelte/tests/server-side-rendering/samples/declaration-tags-transform/main.svelte
new file mode 100644
index 0000000000..d969f907a5
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/declaration-tags-transform/main.svelte
@@ -0,0 +1,4 @@
+<div>
+	{let dt = $derived(Date.parse("2026-10-01T00:00:00Z"))}
+	{typeof dt}
+</div>
\ No newline at end of file

From b1cadd1eae6a709fc5bdc596256b617986a71aaf Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Thu, 2 Jul 2026 16:31:54 +0200
Subject: [PATCH 092/222] chore: drop dead code that make TSGO fail (#18496)

---
 .changeset/big-months-shout.md                          | 5 +++++
 packages/svelte/src/internal/client/reactivity/props.js | 5 +----
 2 files changed, 6 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/big-months-shout.md

diff --git a/.changeset/big-months-shout.md b/.changeset/big-months-shout.md
new file mode 100644
index 0000000000..3d8ca0045e
--- /dev/null
+++ b/.changeset/big-months-shout.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+chore: drop dead code that make TSGO fail
diff --git a/packages/svelte/src/internal/client/reactivity/props.js b/packages/svelte/src/internal/client/reactivity/props.js
index c2f3698809..274d780b1e 100644
--- a/packages/svelte/src/internal/client/reactivity/props.js
+++ b/packages/svelte/src/internal/client/reactivity/props.js
@@ -91,10 +91,7 @@ const rest_props_handler = {
  */
 /*#__NO_SIDE_EFFECTS__*/
 export function rest_props(props, exclude, name) {
-	return new Proxy(
-		DEV ? { props, exclude, name, other: {}, to_proxy: [] } : { props, exclude },
-		rest_props_handler
-	);
+	return new Proxy(DEV ? { props, exclude, name } : { props, exclude }, rest_props_handler);
 }
 
 /**

From 8fb7ceeba5dd1d3b7fc3f587f4e2138bf1b978ed Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Mon, 6 Jul 2026 13:50:56 +0200
Subject: [PATCH 093/222] fix: don't treat declaration tags as parts inside
 each blocks (#18507)

Closes #18506

Declaration tags in the scope of an each block were considered "parts"
and transformed to use their value instead of the signal itself. We can
safely check on the `kind` of the binding since a `kind` of `state`,
`state_raw` or `derived` in the each scope needs to be a declaration tag
(and it's a stable reference so we can use them directly)
---
 .changeset/young-doodles-beam.md                       |  5 +++++
 .../phases/3-transform/client/visitors/shared/utils.js |  6 +++++-
 .../samples/declaration-tags-each/_config.js           | 10 ++++++++++
 .../samples/declaration-tags-each/main.svelte          |  6 ++++++
 4 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/young-doodles-beam.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/declaration-tags-each/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/declaration-tags-each/main.svelte

diff --git a/.changeset/young-doodles-beam.md b/.changeset/young-doodles-beam.md
new file mode 100644
index 0000000000..b68f55d241
--- /dev/null
+++ b/.changeset/young-doodles-beam.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: don't treat declaration tags as parts inside each blocks
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js
index 51c84dd01c..c305d53ea5 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js
@@ -8,7 +8,7 @@ import { sanitize_template_string } from '../../../../../utils/sanitize_template
 import { regex_is_valid_identifier } from '../../../../patterns.js';
 import is_reference from 'is-reference';
 import { dev, is_ignored, locator, component_name } from '../../../../../state.js';
-import { build_getter } from '../../utils.js';
+import { build_getter, is_state_source } from '../../utils.js';
 import { ExpressionMetadata } from '../../../../nodes.js';
 
 /**
@@ -272,6 +272,10 @@ export function build_bind_this(expression, value, { state, visit }) {
 			const binding = state.scope.get(node.name);
 			if (!binding) return;
 
+			// if it is a state or a derived it means is a declaration tag...in that case we don't want to pass the
+			// value but the signal itself or assignment will break
+			if (is_state_source(binding, state.analysis) || binding.kind === 'derived') return;
+
 			for (const [owner, scope] of state.scopes) {
 				if (owner.type === 'EachBlock' && scope === binding.scope) {
 					ids.push(node);
diff --git a/packages/svelte/tests/runtime-runes/samples/declaration-tags-each/_config.js b/packages/svelte/tests/runtime-runes/samples/declaration-tags-each/_config.js
new file mode 100644
index 0000000000..d5cdd103b5
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/declaration-tags-each/_config.js
@@ -0,0 +1,10 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ target, assert }) {
+		const [btn1, btn2] = target.querySelectorAll('button');
+		flushSync(() => btn2.click());
+		assert.equal(btn1.textContent, '1');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/declaration-tags-each/main.svelte b/packages/svelte/tests/runtime-runes/samples/declaration-tags-each/main.svelte
new file mode 100644
index 0000000000..04d55913b4
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/declaration-tags-each/main.svelte
@@ -0,0 +1,6 @@
+{#each Array(1)}
+	{let ref = $state()}
+	{let count = $state(0)}
+	<button onclick={()=>count++} bind:this={ref}>{count}</button>
+	<button onclick={()=>ref.click()}></button>
+{/each}
\ No newline at end of file

From 41642b70ee471dfe024dfface4c0c9939fa60d3b Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Thu, 9 Jul 2026 15:06:08 +0200
Subject: [PATCH 094/222] fix: avoid declaration tag warning in event handlers
 (#18500)

Closes #18493

Co-authored-by: justjavac <justjavac@gmail.com>
---
 .changeset/dull-oranges-fry.md                               | 5 +++++
 .../compiler/phases/2-analyze/visitors/shared/function.js    | 4 +++-
 .../declaration-tag-state-referenced-locally/input.svelte    | 4 ++++
 3 files changed, 12 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/dull-oranges-fry.md

diff --git a/.changeset/dull-oranges-fry.md b/.changeset/dull-oranges-fry.md
new file mode 100644
index 0000000000..0efcc6fa2d
--- /dev/null
+++ b/.changeset/dull-oranges-fry.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: avoid declaration tag warning in event handlers
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/function.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/function.js
index 7bdb2243f2..6b3d227eca 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/function.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/function.js
@@ -18,7 +18,9 @@ export function visit_function(node, context) {
 
 	context.next({
 		...context.state,
-		function_depth: context.state.function_depth + 1,
+		// we generally want to use scope.function_depth unless we specifically increased
+		// that in state.function_depth (e.g. a derived)
+		function_depth: Math.max(context.state.scope.function_depth, context.state.function_depth) + 1,
 		expression: null
 	});
 }
diff --git a/packages/svelte/tests/validator/samples/declaration-tag-state-referenced-locally/input.svelte b/packages/svelte/tests/validator/samples/declaration-tag-state-referenced-locally/input.svelte
index 90cc208e72..f422be9622 100644
--- a/packages/svelte/tests/validator/samples/declaration-tag-state-referenced-locally/input.svelte
+++ b/packages/svelte/tests/validator/samples/declaration-tag-state-referenced-locally/input.svelte
@@ -7,3 +7,7 @@
 {let e = $state(0), f = e}
 
 {a}{b}{c}{d}{e}{f}
+
+<button onclick={() => {
+	console.log(a);
+}}>a</button>
\ No newline at end of file

From 5edd8b0602c81494ebdad7f1a5d8077f869c2097 Mon Sep 17 00:00:00 2001
From: Ivan <273312799+Socialpranker@users.noreply.github.com>
Date: Thu, 9 Jul 2026 23:59:23 +0200
Subject: [PATCH 095/222] fix: chain preprocessor sourcemaps with an empty
 sources[0] (#18518)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

## Summary

Fixes #18491 — the compiler discards an upstream plugin's sourcemap when
it's generated without a `source` option (e.g. `new
MagicString(code).generateMap()`), producing wrong devtools/stack-trace
positions.

### Root cause

`compile()` already supports composing an incoming sourcemap into its
output via `options.sourcemap` (`merge_with_preprocessor_map` →
`apply_preprocessor_sourcemap` → `combine_sourcemaps` in
`packages/svelte/src/compiler/utils/mapped_code.js`). This is the same
mechanism `preprocess()` uses internally, and it's the documented
contract for tools that transform a `.svelte` file before compiling it
(see `CompileOptions.sourcemap`'s doc comment).

`combine_sourcemaps` composes maps by matching `sourcefile === filename`
(the basename of the file being compiled). A sourcemap produced by `new
MagicString(code).generateMap()` **without** a `source` option — which
is exactly what the reporter's Vite plugin does — has `sources: ['']`.
That empty string never equals `filename`, so `remapping()` treats the
node as a leaf (the "original" file) instead of a branch to keep
chaining through, and the whole incoming map is silently dropped. The
result: every position that flows through that segment resolves to `{
source: null, line: null, column: null }`, which is what produces the
wrong/missing devtools mapping described in the issue.

Vite itself already has to handle this exact ambiguity: in
`pluginContainer.ts`'s `_getCombinedSourcemap`, an empty `sources[0]`
from a MagicString-based transform is patched to refer to the file being
transformed before Vite uses it internally. This PR applies the same
normalization on svelte's side, so the contract holds regardless of
whether the caller happens to pass a `source` option to `generateMap()`.

### Fix

In `apply_preprocessor_sourcemap`, normalize an incoming map's `sources:
['']` (or `[null]`/`[undefined]`) to `[filename]` before calling
`combine_sourcemaps`, so the chain-matching step can actually find it.
---
 .changeset/tame-donkeys-jump.md               |  5 ++++
 .../svelte/src/compiler/utils/mapped_code.js  |  7 +++++
 .../samples/sourcemap-empty-source/_config.js | 29 +++++++++++++++++++
 .../sourcemap-empty-source/input.svelte       |  6 ++++
 4 files changed, 47 insertions(+)
 create mode 100644 .changeset/tame-donkeys-jump.md
 create mode 100644 packages/svelte/tests/sourcemaps/samples/sourcemap-empty-source/_config.js
 create mode 100644 packages/svelte/tests/sourcemaps/samples/sourcemap-empty-source/input.svelte

diff --git a/.changeset/tame-donkeys-jump.md b/.changeset/tame-donkeys-jump.md
new file mode 100644
index 0000000000..aae38910db
--- /dev/null
+++ b/.changeset/tame-donkeys-jump.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: chain preprocessor sourcemaps with an empty `sources[0]` instead of dropping them
diff --git a/packages/svelte/src/compiler/utils/mapped_code.js b/packages/svelte/src/compiler/utils/mapped_code.js
index 7686ba59c6..635743c0c4 100644
--- a/packages/svelte/src/compiler/utils/mapped_code.js
+++ b/packages/svelte/src/compiler/utils/mapped_code.js
@@ -311,6 +311,13 @@ function apply_preprocessor_sourcemap(filename, svelte_map, preprocessor_map_inp
 		typeof preprocessor_map_input === 'string'
 			? JSON.parse(preprocessor_map_input)
 			: preprocessor_map_input;
+	// A preprocessor map with a missing/empty `sources[0]` (e.g. from a MagicString transform
+	// created without a `source` option) can't be matched against `filename` during combination,
+	// which silently drops the chain instead of erroring. Normalize it to `filename` first, the
+	// same way Vite treats an empty `sources[0]` as referring to the file being transformed.
+	if (preprocessor_map.sources?.length === 1 && !preprocessor_map.sources[0]) {
+		preprocessor_map.sources = [filename];
+	}
 	const result_map = combine_sourcemaps(filename, [svelte_map, preprocessor_map]);
 	// Svelte expects a SourceMap which includes toUrl and toString. Instead of wrapping our output in a class,
 	// we just tack on the extra properties.
diff --git a/packages/svelte/tests/sourcemaps/samples/sourcemap-empty-source/_config.js b/packages/svelte/tests/sourcemaps/samples/sourcemap-empty-source/_config.js
new file mode 100644
index 0000000000..43a2a4c16a
--- /dev/null
+++ b/packages/svelte/tests/sourcemaps/samples/sourcemap-empty-source/_config.js
@@ -0,0 +1,29 @@
+import * as fs from 'node:fs';
+import MagicString from 'magic-string';
+import { test } from '../../test';
+
+// Simulates a bundler plugin (e.g. a Vite plugin using `magic-string`) that transforms
+// the Svelte source *before* it reaches `compile()`, and hands its own sourcemap to
+// `compileOptions.sourcemap` — the documented way to let svelte chain an upstream map
+// into its own output map. Crucially, the upstream map is generated *without* a `source`
+// option, exactly like `new MagicString(code).generateMap()` — this yields a sourcemap
+// whose `sources` is `['']`, which previously broke the chain entirely (see #18491)
+// instead of being treated as "this file", causing every mapping through it to resolve
+// to `{ source: null, line: null, column: null }`.
+const input = fs.readFileSync(new URL('./input.svelte', import.meta.url), 'utf-8');
+const src = new MagicString(input);
+src.overwrite(
+	src.original.indexOf('count * 2'),
+	src.original.indexOf('count * 2') + 'count * 2'.length,
+	'count * 2',
+	{
+		storeName: false
+	}
+);
+
+export default test({
+	compileOptions: {
+		sourcemap: src.generateMap({ hires: true })
+	},
+	client: [{ str: 'let doubled' }]
+});
diff --git a/packages/svelte/tests/sourcemaps/samples/sourcemap-empty-source/input.svelte b/packages/svelte/tests/sourcemaps/samples/sourcemap-empty-source/input.svelte
new file mode 100644
index 0000000000..b4e0b50bdb
--- /dev/null
+++ b/packages/svelte/tests/sourcemaps/samples/sourcemap-empty-source/input.svelte
@@ -0,0 +1,6 @@
+<script>
+	let count = 0;
+	let doubled = count * 2;
+</script>
+
+<button>clicks: {count}</button>

From c2b7642263ec1f9d89f5d027d68f272742c449a7 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Fri, 10 Jul 2026 15:24:35 +0200
Subject: [PATCH 096/222] chore: add benchmarks (#18523)

Add two kairo variants to better measure of `#traverse` / block effects
perf
---
 .../tests/kairo_broad_block.bench.js          | 47 ++++++++++++++++++
 .../tests/kairo_deep_block.bench.js           | 48 +++++++++++++++++++
 2 files changed, 95 insertions(+)
 create mode 100644 benchmarking/benchmarks/reactivity/tests/kairo_broad_block.bench.js
 create mode 100644 benchmarking/benchmarks/reactivity/tests/kairo_deep_block.bench.js

diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_broad_block.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_broad_block.bench.js
new file mode 100644
index 0000000000..e8451ec3fa
--- /dev/null
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_broad_block.bench.js
@@ -0,0 +1,47 @@
+import assert from 'node:assert';
+import * as $ from 'svelte/internal/client';
+import { block } from '../../../../packages/svelte/src/internal/client/reactivity/effects.js';
+
+// Like `kairo_broad`, but each derived is also read by a block effect, as
+// happens with e.g. `{#if derived}` in a component. Measures our #traverse perf better.
+export default () => {
+	let head = $.state(0);
+	let last = head;
+	let counter = 0;
+
+	const destroy = $.effect_root(() => {
+		for (let i = 0; i < 50; i++) {
+			let current = $.derived(() => {
+				return $.get(head) + i;
+			});
+			let current2 = $.derived(() => {
+				return $.get(current) + 1;
+			});
+			block(() => {
+				$.get(current2);
+			});
+			$.render_effect(() => {
+				$.get(current2);
+				counter++;
+			});
+			last = current2;
+		}
+	});
+
+	return {
+		destroy,
+		run() {
+			$.flush(() => {
+				$.set(head, 1);
+			});
+			counter = 0;
+			for (let i = 0; i < 50; i++) {
+				$.flush(() => {
+					$.set(head, i);
+				});
+				assert.equal($.get(last), i + 50);
+			}
+			assert.equal(counter, 50 * 50);
+		}
+	};
+};
diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_deep_block.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_deep_block.bench.js
new file mode 100644
index 0000000000..a8d9fa8c35
--- /dev/null
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_deep_block.bench.js
@@ -0,0 +1,48 @@
+import assert from 'node:assert';
+import * as $ from 'svelte/internal/client';
+import { block } from '../../../../packages/svelte/src/internal/client/reactivity/effects.js';
+
+let len = 50;
+const iter = 50;
+
+// Like `kairo_deep`, but the derived chain is also read by a block effect, as
+// happens with e.g. `{#if derived}` in a component. Measures our #traverse perf better.
+export default () => {
+	let head = $.state(0);
+	let current = head;
+	for (let i = 0; i < len; i++) {
+		let c = current;
+		current = $.derived(() => {
+			return $.get(c) + 1;
+		});
+	}
+	let counter = 0;
+
+	const destroy = $.effect_root(() => {
+		block(() => {
+			$.get(current);
+		});
+
+		$.render_effect(() => {
+			$.get(current);
+			counter++;
+		});
+	});
+
+	return {
+		destroy,
+		run() {
+			$.flush(() => {
+				$.set(head, 1);
+			});
+			counter = 0;
+			for (let i = 0; i < iter; i++) {
+				$.flush(() => {
+					$.set(head, i);
+				});
+				assert.equal($.get(current), len + i);
+			}
+			assert.equal(counter, iter);
+		}
+	};
+};

From bfbb026f2f7db6ced0d86ba0feb40587c0e8f598 Mon Sep 17 00:00:00 2001
From: JY Wey <34165386+JaiWey@users.noreply.github.com>
Date: Sat, 11 Jul 2026 01:42:01 +1200
Subject: [PATCH 097/222] fix: skip unnecessary derived effect in earlier batch
 (#18525)

fixes #18438
Currently the `mark` method inside `#merge` for `earlier_batch` will
schedule effect for undirty derived. Add the condition for derived to
prevent unnecessary effect be scheduled.

```
if ((flags & DERIVED) !== 0) {
	mark(/** @type {Derived} */ (reaction));
}
```
---
 .changeset/curly-wasps-hide.md                |  5 ++++
 .../src/internal/client/reactivity/batch.js   |  6 ++++
 .../samples/async-batch-derived/_config.js    | 28 ++++++++++++++++++
 .../samples/async-batch-derived/main.svelte   | 29 +++++++++++++++++++
 4 files changed, 68 insertions(+)
 create mode 100644 .changeset/curly-wasps-hide.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-batch-derived/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-batch-derived/main.svelte

diff --git a/.changeset/curly-wasps-hide.md b/.changeset/curly-wasps-hide.md
new file mode 100644
index 0000000000..7e55d77ba0
--- /dev/null
+++ b/.changeset/curly-wasps-hide.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: skip unnecessary derived effect in earlier batch
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 7d14b80519..5becae2dc9 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -530,6 +530,12 @@ export class Batch {
 		const mark = (value) => {
 			var reactions = value.reactions;
 			if (reactions === null) return;
+			// skip if value is derived and is neither dirty nor maybe dirty. transitive
+			// deriveds (a derived depending on another derived) are only MAYBE_DIRTY, so
+			// we must continue traversing them to reach the effects that depend on them
+			if ((value.f & DERIVED) !== 0 && (value.f & (DIRTY | MAYBE_DIRTY)) === 0) {
+				return;
+			}
 
 			for (const reaction of reactions) {
 				var flags = reaction.f;
diff --git a/packages/svelte/tests/runtime-runes/samples/async-batch-derived/_config.js b/packages/svelte/tests/runtime-runes/samples/async-batch-derived/_config.js
new file mode 100644
index 0000000000..d5286d9d95
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-batch-derived/_config.js
@@ -0,0 +1,28 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		const [increment, pop] = target.querySelectorAll('button');
+
+		increment.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`<button>increment</button> <button>pop</button> <p>Loading...</p>`
+		);
+		increment.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`<button>increment</button> <button>pop</button> <p>Loading...</p>`
+		);
+		pop.click();
+		await tick();
+		assert.htmlEqual(target.innerHTML, `<button>increment</button> <button>pop</button> 2 2 1`);
+
+		pop.click();
+		await tick();
+		assert.htmlEqual(target.innerHTML, `<button>increment</button> <button>pop</button> 2 2 1`);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-batch-derived/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-batch-derived/main.svelte
new file mode 100644
index 0000000000..af7f0f468c
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-batch-derived/main.svelte
@@ -0,0 +1,29 @@
+<script>
+	let count = $state(0);
+	let other = $state(0);
+
+	const queue = [];
+  	let pending = $derived(defaultPending);
+	function push(v) {
+		return new Promise((resolve) => queue.push(() => resolve(v)));
+	}
+</script>
+
+<button onclick={() => {
+	if (count === 0) {
+		other++;
+		count++;
+	} else {
+		count++
+	}
+}}>increment</button>
+<button onclick={() => queue.pop()?.()}>pop</button>
+{#snippet defaultPending()}
+  <p>Loading...</p>
+{/snippet}
+
+{#if count > 0}
+	<svelte:boundary {pending}>
+		{await push(count)} {count} {other}
+	</svelte:boundary> 
+{/if}

From 08a9e9e7e43453e2146357dd72d44cca1e41e29e Mon Sep 17 00:00:00 2001
From: Rabindra Kumar Meher <rabindrameher116@gmail.com>
Date: Fri, 10 Jul 2026 19:29:34 +0530
Subject: [PATCH 098/222] fix: prevent derived connection leak in untracked
 contexts (#18517)

Fixes #18501.

Problem is that is_updating_effect was also set to true for branch/root effects which are not reactive

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 packages/svelte/src/internal/client/runtime.js |  5 ++++-
 packages/svelte/tests/signals/test.ts          | 18 ++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 227203523e..188d16a820 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -61,6 +61,9 @@ import { without_reactive_context } from './dom/elements/bindings/shared.js';
 import { set_signal_status, update_derived_status } from './reactivity/status.js';
 import * as w from './warnings.js';
 
+/**
+ * True if updating in an effect context that is reactive (i.e. not branch/root effects)
+ */
 let is_updating_effect = false;
 
 export let is_destroying_effect = false;
@@ -444,7 +447,7 @@ export function update_effect(effect) {
 	var was_updating_effect = is_updating_effect;
 
 	active_effect = effect;
-	is_updating_effect = true;
+	is_updating_effect = (flags & (BRANCH_EFFECT | ROOT_EFFECT)) === 0; // Branch/root effects are not reactive contexts
 
 	if (DEV) {
 		var previous_component_fn = dev_current_component_function;
diff --git a/packages/svelte/tests/signals/test.ts b/packages/svelte/tests/signals/test.ts
index 927ce2e665..07f79bd395 100644
--- a/packages/svelte/tests/signals/test.ts
+++ b/packages/svelte/tests/signals/test.ts
@@ -1503,4 +1503,22 @@ describe('signals', () => {
 			assert.deepEqual(log, ['inner destroyed', 'inner destroyed']);
 		};
 	});
+
+	test('derived read in an untracked context should not leak in deps reactions', () => {
+		return () => {
+			let s = state('hello');
+			let a = derived(() => $.get(s));
+			let b = derived(() => $.get(a));
+
+			let destroy = effect_root(() => {
+				$.get(b);
+			});
+
+			destroy();
+
+			// a was spuriously added to s.reactions via is_updating_effect
+			// even though the entire derived chain was read in an untracked context
+			assert.equal(s.reactions, null);
+		};
+	});
 });

From 8e4f26552c7dd40cc056a28357f6171542d2549d Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Fri, 10 Jul 2026 16:01:20 +0200
Subject: [PATCH 099/222] chore: changeset (#18527)

for #18517
---
 .changeset/common-ways-deny.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/common-ways-deny.md

diff --git a/.changeset/common-ways-deny.md b/.changeset/common-ways-deny.md
new file mode 100644
index 0000000000..75e9375965
--- /dev/null
+++ b/.changeset/common-ways-deny.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: don't (re)connect deriveds when read inside branch/root effects

From b4d1583ae20f3869a88a731d9a265c546c099f66 Mon Sep 17 00:00:00 2001
From: Thribhuvan <thribhuvan003@gmail.com>
Date: Fri, 10 Jul 2026 19:31:48 +0530
Subject: [PATCH 100/222] fix: transform computed keys in keyed each block
 destructuring patterns (#18521)

fixes #18519
---
 .changeset/shiny-keys-dance.md                |  5 ++++
 .../3-transform/client/visitors/EachBlock.js  |  5 +++-
 .../Child.svelte                              |  7 +++++
 .../_config.js                                | 29 +++++++++++++++++++
 .../main.svelte                               | 12 ++++++++
 5 files changed, 57 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/shiny-keys-dance.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/each-keyed-computed-destructuring-key/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/each-keyed-computed-destructuring-key/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/each-keyed-computed-destructuring-key/main.svelte

diff --git a/.changeset/shiny-keys-dance.md b/.changeset/shiny-keys-dance.md
new file mode 100644
index 0000000000..20cf754212
--- /dev/null
+++ b/.changeset/shiny-keys-dance.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: transform computed keys in keyed `{#each}` destructuring patterns
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/EachBlock.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/EachBlock.js
index a1371b516a..b33eddd461 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/EachBlock.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/EachBlock.js
@@ -294,7 +294,10 @@ export function EachBlock(node, context) {
 	let key_function = b.id('$.index');
 
 	if (node.metadata.keyed) {
-		const pattern = /** @type {Pattern} */ (node.context); // can only be keyed when a context is provided
+		// can only be keyed when a context is provided
+		const pattern = /** @type {Pattern} */ (
+			context.visit(/** @type {Pattern} */ (node.context), key_state)
+		);
 		const expression = /** @type {Expression} */ (
 			context.visit(/** @type {Expression} */ (node.key), key_state)
 		);
diff --git a/packages/svelte/tests/runtime-runes/samples/each-keyed-computed-destructuring-key/Child.svelte b/packages/svelte/tests/runtime-runes/samples/each-keyed-computed-destructuring-key/Child.svelte
new file mode 100644
index 0000000000..35544d0a55
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/each-keyed-computed-destructuring-key/Child.svelte
@@ -0,0 +1,7 @@
+<script>
+	let { labelKey, valueKey, options } = $props();
+</script>
+
+{#each options as { [labelKey]: label, [valueKey]: value } (value)}
+	<p>{label}: {value}</p>
+{/each}
diff --git a/packages/svelte/tests/runtime-runes/samples/each-keyed-computed-destructuring-key/_config.js b/packages/svelte/tests/runtime-runes/samples/each-keyed-computed-destructuring-key/_config.js
new file mode 100644
index 0000000000..8a8789d712
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/each-keyed-computed-destructuring-key/_config.js
@@ -0,0 +1,29 @@
+import { flushSync } from 'svelte';
+import { ok, test } from '../../test';
+
+// https://github.com/sveltejs/svelte/issues/18519
+export default test({
+	html: `
+		<button>reverse</button>
+		<p>1: a1</p>
+		<p>2: a2</p>
+		<p>3: a3</p>
+	`,
+
+	test({ assert, target }) {
+		const btn = target.querySelector('button');
+		ok(btn);
+
+		flushSync(() => btn.click());
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>reverse</button>
+				<p>3: a3</p>
+				<p>2: a2</p>
+				<p>1: a1</p>
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/each-keyed-computed-destructuring-key/main.svelte b/packages/svelte/tests/runtime-runes/samples/each-keyed-computed-destructuring-key/main.svelte
new file mode 100644
index 0000000000..6885a6918e
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/each-keyed-computed-destructuring-key/main.svelte
@@ -0,0 +1,12 @@
+<script>
+	import Child from './Child.svelte';
+
+	let options = $state([
+		{ a: 1, v: 'a1' },
+		{ a: 2, v: 'a2' },
+		{ a: 3, v: 'a3' }
+	]);
+</script>
+
+<button onclick={() => options.reverse()}>reverse</button>
+<Child {options} labelKey="a" valueKey="v" />

From af6f1d309b0fc7a9dcde7099b5f231078c9f5738 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Tue, 14 Jul 2026 00:06:53 +0200
Subject: [PATCH 101/222] chore: run every benchmark in its own process
 (#18542)

While benchmarking it became apparent that when running the full `pnpm
bench:compare` suite results could be wildly different compared to only
comparing single benchmarks. The reason (most likely) is that the
heap/GC/JIT state from one benchmark contaminates the others.

Therefore this adjusts the runners such that each benchmark entry is run
in its own forked process, not just each branch. This should give
better, more stable results.

Also a little fix to compare results by name; I made the mistake of
adding a new benchmark to main which wasn't present on other branches
yet, which made the results really confusing.
---
 benchmarking/compare/generate-report.js |  33 +++-
 benchmarking/compare/runner.js          |  73 +++++++--
 benchmarking/run.js                     | 203 +++++++++++++++---------
 3 files changed, 220 insertions(+), 89 deletions(-)

diff --git a/benchmarking/compare/generate-report.js b/benchmarking/compare/generate-report.js
index a61f58909b..a06aaf9fc2 100644
--- a/benchmarking/compare/generate-report.js
+++ b/benchmarking/compare/generate-report.js
@@ -33,11 +33,38 @@ export function generate_report(outdir) {
 
 	write('');
 
-	for (let i = 0; i < results[0].length; i += 1) {
-		write(`${results[0][i].benchmark}`);
+	// match results by benchmark name — branches may have different benchmark
+	// lists (e.g. a benchmark that only exists on one of the branches), so
+	// pairing by array index would misattribute results
+	const by_name = results.map((result) => new Map(result.map((r) => [r.benchmark, r])));
+
+	/** @type {string[]} */
+	const names = [];
+
+	for (const result of results) {
+		for (const { benchmark } of result) {
+			if (!names.includes(benchmark)) {
+				names.push(benchmark);
+			}
+		}
+	}
+
+	for (const name of names) {
+		const entries = by_name.map((map) => map.get(name));
+		const missing = entries
+			.map((entry, b) => (entry === undefined ? branches[b] : null))
+			.filter((branch) => branch !== null);
+
+		write(`${name}`);
+
+		if (missing.length > 0) {
+			write(`  skipped (missing on ${missing.join(', ')})`);
+			write('');
+			continue;
+		}
 
 		for (const metric of ['time', 'gc_time']) {
-			const times = results.map((result) => +result[i][metric]);
+			const times = entries.map((entry) => +entry[metric]);
 			let min = Infinity;
 			let max = -Infinity;
 			let min_index = -1;
diff --git a/benchmarking/compare/runner.js b/benchmarking/compare/runner.js
index 31a8e6b44b..fa746f9869 100644
--- a/benchmarking/compare/runner.js
+++ b/benchmarking/compare/runner.js
@@ -1,18 +1,67 @@
+import { fork } from 'node:child_process';
+import { fileURLToPath } from 'node:url';
 import { reactivity_benchmarks } from '../benchmarks/reactivity/index.js';
 import { with_cpu_profile } from '../utils.js';
 
-const results = [];
-const PROFILE_DIR = process.env.BENCH_PROFILE_DIR;
+const PROFILE_DIR = process.env.BENCH_PROFILE_DIR ?? null;
+const single = process.env.BENCH_SINGLE;
 
-for (let i = 0; i < reactivity_benchmarks.length; i += 1) {
-	const benchmark = reactivity_benchmarks[i];
+if (single) {
+	// child mode — run a single benchmark and report the result to the parent
+	const benchmark = reactivity_benchmarks.find((b) => b.label === single);
 
-	process.stderr.write(`Running ${i + 1}/${reactivity_benchmarks.length} ${benchmark.label} `);
-	results.push({
-		benchmark: benchmark.label,
-		...(await with_cpu_profile(PROFILE_DIR, benchmark.label, () => benchmark.fn()))
-	});
-	process.stderr.write('\x1b[2K\r');
-}
+	if (!benchmark) {
+		throw new Error(`Unknown benchmark ${single}`);
+	}
+
+	const result = await with_cpu_profile(PROFILE_DIR, benchmark.label, () => benchmark.fn());
+
+	// exit via the callback so the message is guaranteed to be delivered
+	/** @type {NodeJS.Process} */ (process).send(result, () => process.exit(0));
+} else {
+	// parent mode — run every benchmark in its own child process, so that
+	// heap/GC/JIT state from one benchmark cannot contaminate the others
+	const filename = fileURLToPath(import.meta.url);
+	const results = [];
+
+	for (let i = 0; i < reactivity_benchmarks.length; i += 1) {
+		const benchmark = reactivity_benchmarks[i];
+
+		process.stderr.write(`Running ${i + 1}/${reactivity_benchmarks.length} ${benchmark.label} `);
+
+		const result = await new Promise((fulfil, reject) => {
+			const child = fork(filename, [], {
+				env: {
+					...process.env,
+					BENCH_SINGLE: benchmark.label
+				}
+			});
+
+			/** @type {object | null} */
+			let message_received = null;
 
-process.send(results);
+			child.on('message', (message) => {
+				message_received = /** @type {object} */ (message);
+			});
+
+			child.on('error', reject);
+
+			child.on('exit', (code) => {
+				if (message_received === null) {
+					reject(new Error(`benchmark ${benchmark.label} exited with code ${code}`));
+				} else {
+					fulfil(message_received);
+				}
+			});
+		});
+
+		results.push({
+			benchmark: benchmark.label,
+			.../** @type {object} */ (result)
+		});
+
+		process.stderr.write('\x1b[2K\r');
+	}
+
+	/** @type {NodeJS.Process} */ (process).send(results);
+}
diff --git a/benchmarking/run.js b/benchmarking/run.js
index 80e40a5ff1..e44e816dd0 100644
--- a/benchmarking/run.js
+++ b/benchmarking/run.js
@@ -1,94 +1,149 @@
+import { fork } from 'node:child_process';
+import { fileURLToPath } from 'node:url';
 import * as $ from '../packages/svelte/src/internal/client/index.js';
 import { reactivity_benchmarks } from './benchmarks/reactivity/index.js';
 import { ssr_benchmarks } from './benchmarks/ssr/index.js';
 import { with_cpu_profile } from './utils.js';
 
-// e.g. `pnpm bench kairo` to only run the kairo benchmarks
-const filters = process.argv.slice(2);
-
 const PROFILE_DIR = './benchmarking/.profiles';
 
-const suites = [
-	{
-		benchmarks: reactivity_benchmarks.filter(
-			(b) => filters.length === 0 || filters.some((f) => b.label.includes(f))
-		),
-		name: 'reactivity benchmarks'
-	},
-	{
-		benchmarks: ssr_benchmarks.filter(
-			(b) => filters.length === 0 || filters.some((f) => b.label.includes(f))
-		),
-		name: 'server-side rendering benchmarks'
-	}
-].filter((suite) => suite.benchmarks.length > 0);
-
-if (suites.length === 0) {
-	console.log('No benchmarks matched provided filters');
-	process.exit(1);
-}
-
-const COLUMN_WIDTHS = [25, 9, 9];
-const TOTAL_WIDTH = COLUMN_WIDTHS.reduce((a, b) => a + b);
-
-const pad_right = (str, n) => str + ' '.repeat(n - str.length);
-const pad_left = (str, n) => ' '.repeat(n - str.length) + str;
+const single = process.env.BENCH_SINGLE;
 
-let total_time = 0;
-let total_gc_time = 0;
+if (single) {
+	// child mode — run a single benchmark and report the result to the parent
+	const benchmark = [...reactivity_benchmarks, ...ssr_benchmarks].find((b) => b.label === single);
 
-$.push({}, true);
+	if (!benchmark) {
+		throw new Error(`Unknown benchmark ${single}`);
+	}
 
-try {
-	for (const { benchmarks, name } of suites) {
-		let suite_time = 0;
-		let suite_gc_time = 0;
+	$.push({}, true);
+
+	const result = await with_cpu_profile(PROFILE_DIR, benchmark.label, () => benchmark.fn());
+
+	$.pop();
+
+	// exit via the callback so the message is guaranteed to be delivered
+	/** @type {NodeJS.Process} */ (process).send(result, () => process.exit(0));
+} else {
+	// parent mode — run every benchmark in its own child process, so that
+	// heap/GC/JIT state from one benchmark cannot contaminate the others
+
+	// e.g. `pnpm bench kairo` to only run the kairo benchmarks
+	const filters = process.argv.slice(2);
+
+	const suites = [
+		{
+			benchmarks: reactivity_benchmarks.filter(
+				(b) => filters.length === 0 || filters.some((f) => b.label.includes(f))
+			),
+			name: 'reactivity benchmarks'
+		},
+		{
+			benchmarks: ssr_benchmarks.filter(
+				(b) => filters.length === 0 || filters.some((f) => b.label.includes(f))
+			),
+			name: 'server-side rendering benchmarks'
+		}
+	].filter((suite) => suite.benchmarks.length > 0);
 
-		console.log(`\nRunning ${name}...\n`);
-		console.log(
-			pad_right('Benchmark', COLUMN_WIDTHS[0]) +
-				pad_left('Time', COLUMN_WIDTHS[1]) +
-				pad_left('GC time', COLUMN_WIDTHS[2])
-		);
-		console.log('='.repeat(TOTAL_WIDTH));
+	if (suites.length === 0) {
+		console.log('No benchmarks matched provided filters');
+		process.exit(1);
+	}
 
-		for (const benchmark of benchmarks) {
-			const results = await with_cpu_profile(PROFILE_DIR, benchmark.label, () => benchmark.fn());
+	const filename = fileURLToPath(import.meta.url);
+
+	/**
+	 * @param {string} label
+	 * @returns {Promise<{ time: number, gc_time: number }>}
+	 */
+	const run_benchmark = (label) => {
+		return new Promise((fulfil, reject) => {
+			const child = fork(filename, [], {
+				env: {
+					...process.env,
+					BENCH_SINGLE: label
+				}
+			});
+
+			/** @type {{ time: number, gc_time: number } | null} */
+			let result = null;
+
+			child.on('message', (message) => {
+				result = /** @type {{ time: number, gc_time: number }} */ (message);
+			});
+
+			child.on('error', reject);
+
+			child.on('exit', (code) => {
+				if (result === null) {
+					reject(new Error(`benchmark ${label} exited with code ${code}`));
+				} else {
+					fulfil(result);
+				}
+			});
+		});
+	};
+
+	const COLUMN_WIDTHS = [25, 9, 9];
+	const TOTAL_WIDTH = COLUMN_WIDTHS.reduce((a, b) => a + b);
+
+	/** @type {(str: string, n: number) => string} */
+	const pad_right = (str, n) => str + ' '.repeat(n - str.length);
+	/** @type {(str: string, n: number) => string} */
+	const pad_left = (str, n) => ' '.repeat(n - str.length) + str;
+
+	let total_time = 0;
+	let total_gc_time = 0;
+
+	try {
+		for (const { benchmarks, name } of suites) {
+			let suite_time = 0;
+			let suite_gc_time = 0;
+
+			console.log(`\nRunning ${name}...\n`);
+			console.log(
+				pad_right('Benchmark', COLUMN_WIDTHS[0]) +
+					pad_left('Time', COLUMN_WIDTHS[1]) +
+					pad_left('GC time', COLUMN_WIDTHS[2])
+			);
+			console.log('='.repeat(TOTAL_WIDTH));
+
+			for (const benchmark of benchmarks) {
+				const results = await run_benchmark(benchmark.label);
+				console.log(
+					pad_right(benchmark.label, COLUMN_WIDTHS[0]) +
+						pad_left(results.time.toFixed(2), COLUMN_WIDTHS[1]) +
+						pad_left(results.gc_time.toFixed(2), COLUMN_WIDTHS[2])
+				);
+				total_time += results.time;
+				total_gc_time += results.gc_time;
+				suite_time += results.time;
+				suite_gc_time += results.gc_time;
+			}
+
+			console.log('='.repeat(TOTAL_WIDTH));
 			console.log(
-				pad_right(benchmark.label, COLUMN_WIDTHS[0]) +
-					pad_left(results.time.toFixed(2), COLUMN_WIDTHS[1]) +
-					pad_left(results.gc_time.toFixed(2), COLUMN_WIDTHS[2])
+				pad_right('suite', COLUMN_WIDTHS[0]) +
+					pad_left(suite_time.toFixed(2), COLUMN_WIDTHS[1]) +
+					pad_left(suite_gc_time.toFixed(2), COLUMN_WIDTHS[2])
 			);
-			total_time += results.time;
-			total_gc_time += results.gc_time;
-			suite_time += results.time;
-			suite_gc_time += results.gc_time;
+			console.log('='.repeat(TOTAL_WIDTH));
 		}
 
-		console.log('='.repeat(TOTAL_WIDTH));
-		console.log(
-			pad_right('suite', COLUMN_WIDTHS[0]) +
-				pad_left(suite_time.toFixed(2), COLUMN_WIDTHS[1]) +
-				pad_left(suite_gc_time.toFixed(2), COLUMN_WIDTHS[2])
-		);
-		console.log('='.repeat(TOTAL_WIDTH));
-	}
-
-	if (PROFILE_DIR !== null) {
 		console.log(`\nCPU profiles written to ${PROFILE_DIR}`);
+	} catch (e) {
+		// eslint-disable-next-line no-console
+		console.error(e);
+		process.exit(1);
 	}
-} catch (e) {
-	// eslint-disable-next-line no-console
-	console.error(e);
-	process.exit(1);
-}
 
-$.pop();
+	console.log('');
 
-console.log('');
-
-console.log(
-	pad_right('total', COLUMN_WIDTHS[0]) +
-		pad_left(total_time.toFixed(2), COLUMN_WIDTHS[1]) +
-		pad_left(total_gc_time.toFixed(2), COLUMN_WIDTHS[2])
-);
+	console.log(
+		pad_right('total', COLUMN_WIDTHS[0]) +
+			pad_left(total_time.toFixed(2), COLUMN_WIDTHS[1]) +
+			pad_left(total_gc_time.toFixed(2), COLUMN_WIDTHS[2])
+	);
+}

From 4da9f74cd95e838acc56c4aa0d2e926d5f68972d Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Tue, 14 Jul 2026 00:07:24 +0200
Subject: [PATCH 102/222] chore: bench compare report as HTML (#18543)

Creates a `results.html` file which is much better to look at compared
to the terminal output.
---
 .gitignore                                 |   1 +
 benchmarking/compare/generate-report.js    |  46 +-
 benchmarking/compare/index.js              |   2 +-
 benchmarking/compare/results.template.html | 741 +++++++++++++++++++++
 4 files changed, 785 insertions(+), 5 deletions(-)
 create mode 100644 benchmarking/compare/results.template.html

diff --git a/.gitignore b/.gitignore
index 556cae6344..e4f9f9cf87 100644
--- a/.gitignore
+++ b/.gitignore
@@ -27,3 +27,4 @@ packages/svelte/scripts/_baseline/
 benchmarking/.profiles
 benchmarking/compare/.results
 benchmarking/compare/.profiles
+benchmarking/compare/results.html
diff --git a/benchmarking/compare/generate-report.js b/benchmarking/compare/generate-report.js
index a06aaf9fc2..70f7b30fbb 100644
--- a/benchmarking/compare/generate-report.js
+++ b/benchmarking/compare/generate-report.js
@@ -2,15 +2,27 @@ import fs from 'node:fs';
 import path from 'node:path';
 import { pathToFileURL } from 'node:url';
 
-export function generate_report(outdir) {
+const REPORT_DATA_PLACEHOLDER = '%%REPORT_DATA%%';
+const report_template = fs.readFileSync(
+	new URL('./results.template.html', import.meta.url),
+	'utf-8'
+);
+
+if (!report_template.includes(REPORT_DATA_PLACEHOLDER)) {
+	throw new Error(`Missing ${REPORT_DATA_PLACEHOLDER} in results.template.html`);
+}
+
+export function generate_report(outdir, branches) {
 	const result_files = fs
 		.readdirSync(outdir)
-		.filter((file) => file.endsWith('.json'))
+		.filter((file) => file.endsWith('.json') && (!branches || branches.includes(file.slice(0, -5))))
 		.sort((a, b) => a.localeCompare(b));
 
-	const branches = result_files.map((file) => file.slice(0, -5));
+	// always do this so that ordering lines up (branches argument might be passed in a different order than the result files are sorted
+	branches = result_files.map((file) => file.slice(0, -5));
+
 	const results = result_files.map((file) =>
-		JSON.parse(fs.readFileSync(`${outdir}/${file}`, 'utf-8'))
+		JSON.parse(fs.readFileSync(path.join(outdir, file), 'utf-8'))
 	);
 
 	if (results.length === 0) {
@@ -95,6 +107,32 @@ export function generate_report(outdir) {
 
 		write('');
 	}
+
+	const benchmarks = names.map((name) => ({
+		name,
+		values: by_name.map((map) => {
+			const entry = map.get(name);
+
+			if (entry === undefined) return null;
+
+			return {
+				time: Number(entry.time),
+				gc_time: Number(entry.gc_time)
+			};
+		})
+	}));
+	const data = JSON.stringify({
+		generated_at: new Date().toISOString(),
+		branches,
+		benchmarks
+	})
+		.replaceAll('<', '\\u003c')
+		.replaceAll('\u2028', '\\u2028')
+		.replaceAll('\u2029', '\\u2029');
+	const html_file = path.resolve(outdir, '../results.html');
+
+	fs.writeFileSync(html_file, report_template.replace(REPORT_DATA_PLACEHOLDER, data));
+	console.log(`\nHTML report written to ${html_file}`);
 }
 
 function char(i) {
diff --git a/benchmarking/compare/index.js b/benchmarking/compare/index.js
index 9064ee7da9..2e76f46e1b 100644
--- a/benchmarking/compare/index.js
+++ b/benchmarking/compare/index.js
@@ -85,4 +85,4 @@ if (PROFILE_DIR !== null) {
 	console.log(`\nCPU profiles written to ${PROFILE_DIR}`);
 }
 
-generate_report(outdir);
+generate_report(outdir, requested_branches);
diff --git a/benchmarking/compare/results.template.html b/benchmarking/compare/results.template.html
new file mode 100644
index 0000000000..02f208ac4f
--- /dev/null
+++ b/benchmarking/compare/results.template.html
@@ -0,0 +1,741 @@
+<!doctype html>
+<html lang="en">
+	<head>
+		<meta charset="utf-8" />
+		<meta name="viewport" content="width=device-width, initial-scale=1" />
+		<title>Benchmark comparison</title>
+		<style>
+			:root {
+				color-scheme: light;
+				font-family:
+					Inter,
+					ui-sans-serif,
+					system-ui,
+					-apple-system,
+					BlinkMacSystemFont,
+					'Segoe UI',
+					sans-serif;
+				font-variant-numeric: tabular-nums;
+				background: #f6f8fa;
+				color: #1f2328;
+			}
+
+			* {
+				box-sizing: border-box;
+			}
+
+			body {
+				margin: 0;
+				background: #f6f8fa;
+			}
+
+			main {
+				width: min(1600px, 100%);
+				margin: 0 auto;
+				padding: 40px clamp(16px, 3vw, 48px) 64px;
+			}
+
+			h1,
+			h2,
+			p {
+				margin-top: 0;
+			}
+
+			h1 {
+				margin-bottom: 8px;
+				font-size: clamp(28px, 4vw, 48px);
+				letter-spacing: -0.04em;
+			}
+
+			h2 {
+				margin-bottom: 14px;
+				font-size: 18px;
+				letter-spacing: -0.01em;
+			}
+
+			.intro {
+				max-width: 780px;
+				margin-bottom: 28px;
+				color: #59636e;
+				line-height: 1.6;
+			}
+
+			.summary {
+				display: grid;
+				grid-template-columns: repeat(3, minmax(0, 1fr));
+				gap: 12px;
+				margin-bottom: 32px;
+			}
+
+			.card,
+			.panel {
+				border: 1px solid #d0d7de;
+				background: #ffffff;
+				box-shadow: 0 8px 24px rgb(140 149 159 / 16%);
+			}
+
+			.card {
+				min-height: 112px;
+				padding: 18px 20px;
+				border-radius: 8px;
+			}
+
+			.card-label {
+				margin-bottom: 10px;
+				color: #59636e;
+				font-size: 12px;
+				font-weight: 700;
+				letter-spacing: 0.08em;
+				text-transform: uppercase;
+			}
+
+			.card-value {
+				font-size: 21px;
+				font-weight: 750;
+				letter-spacing: -0.02em;
+			}
+
+			.card-detail {
+				margin-top: 7px;
+				color: #59636e;
+				font-size: 13px;
+			}
+
+			.panel {
+				margin-bottom: 24px;
+				border-radius: 8px;
+				overflow: hidden;
+			}
+
+			.panel-heading {
+				display: flex;
+				align-items: end;
+				justify-content: space-between;
+				gap: 20px;
+				padding: 18px 20px;
+				border-bottom: 1px solid #d8dee4;
+			}
+
+			.panel-heading h2,
+			.panel-heading p {
+				margin-bottom: 0;
+			}
+
+			.help {
+				max-width: 720px;
+				color: #59636e;
+				font-size: 13px;
+				line-height: 1.5;
+			}
+
+			.controls {
+				display: flex;
+				flex-wrap: wrap;
+				gap: 12px;
+				padding: 14px 20px;
+				border-bottom: 1px solid #d8dee4;
+				background: #f6f8fa;
+			}
+
+			label {
+				display: flex;
+				align-items: center;
+				gap: 8px;
+				color: #59636e;
+				font-size: 13px;
+				font-weight: 650;
+			}
+
+			select {
+				max-width: 250px;
+				padding: 7px 30px 7px 9px;
+				border: 1px solid #afb8c1;
+				border-radius: 5px;
+				background: #ffffff;
+				color: #1f2328;
+				font: inherit;
+			}
+
+			.table-wrap {
+				overflow: auto;
+			}
+
+			table {
+				width: 100%;
+				border-collapse: separate;
+				border-spacing: 0;
+			}
+
+			th,
+			td {
+				padding: 11px 14px;
+				border-right: 1px solid #d8dee4;
+				border-bottom: 1px solid #d8dee4;
+				text-align: left;
+				vertical-align: middle;
+			}
+
+			th:last-child,
+			td:last-child {
+				border-right: 0;
+			}
+
+			tr:last-child td {
+				border-bottom: 0;
+			}
+
+			th {
+				background: #f6f8fa;
+				color: #59636e;
+				font-size: 12px;
+				font-weight: 700;
+				letter-spacing: 0.04em;
+				text-transform: uppercase;
+			}
+
+			th button {
+				width: 100%;
+				padding: 0;
+				border: 0;
+				background: transparent;
+				color: inherit;
+				font: inherit;
+				letter-spacing: inherit;
+				text-align: inherit;
+				text-transform: inherit;
+				cursor: pointer;
+			}
+
+			th button:hover,
+			th button:focus-visible {
+				color: #1f2328;
+			}
+
+			.standings td:nth-child(n + 2),
+			.standings th:nth-child(n + 2) {
+				text-align: right;
+			}
+
+			.rank {
+				display: inline-grid;
+				width: 24px;
+				height: 24px;
+				margin-right: 10px;
+				place-items: center;
+				border-radius: 50%;
+				background: #eaeef2;
+				color: #424a53;
+				font-size: 12px;
+				font-weight: 750;
+			}
+
+			.branch-name,
+			.benchmark-name {
+				font-weight: 700;
+			}
+
+			.benchmark-table {
+				min-width: max(900px, 100%);
+			}
+
+			.benchmark-table thead {
+				position: sticky;
+				top: 0;
+				z-index: 3;
+			}
+
+			.benchmark-table th:first-child,
+			.benchmark-table td:first-child {
+				position: sticky;
+				left: 0;
+				z-index: 2;
+				min-width: 220px;
+				background: #ffffff;
+			}
+
+			.benchmark-table th:first-child {
+				z-index: 4;
+				background: #f6f8fa;
+			}
+
+			.benchmark-table th:nth-child(2),
+			.benchmark-table td:nth-child(2) {
+				min-width: 150px;
+			}
+
+			.benchmark-table th:not(:first-child),
+			.benchmark-table td:not(:first-child) {
+				min-width: 175px;
+			}
+
+			.metric {
+				position: relative;
+				isolation: isolate;
+				background: hsl(var(--heat, 210) 74% 94%);
+			}
+
+			.metric::after {
+				position: absolute;
+				z-index: -1;
+				inset: auto 0 0;
+				height: 3px;
+				background: hsl(var(--heat, 210) 65% 43%);
+				content: '';
+			}
+
+			.time {
+				font-size: 15px;
+				font-weight: 750;
+			}
+
+			.delta {
+				margin-left: 7px;
+				color: #424a53;
+				font-size: 12px;
+				font-weight: 650;
+			}
+
+			.secondary {
+				margin-top: 5px;
+				color: #59636e;
+				font-size: 12px;
+			}
+
+			.winner {
+				color: #1a7f37;
+				font-weight: 700;
+			}
+
+			.missing {
+				background: #f6f8fa;
+				color: #6e7781;
+				font-style: italic;
+			}
+
+			footer {
+				color: #6e7781;
+				font-size: 12px;
+				text-align: right;
+			}
+
+			@media (max-width: 760px) {
+				main {
+					padding-top: 24px;
+				}
+
+				.summary {
+					grid-template-columns: 1fr;
+				}
+
+				.panel-heading {
+					align-items: start;
+					flex-direction: column;
+				}
+
+				.controls,
+				label {
+					align-items: stretch;
+					flex-direction: column;
+				}
+
+				select {
+					max-width: none;
+					width: 100%;
+				}
+			}
+		</style>
+	</head>
+	<body>
+		<main>
+			<h1>Benchmark comparison</h1>
+			<p class="intro">
+				Runtime results across branches. Green cells are fastest for an entry and red cells expose
+				the largest regressions. Overall runtime normalizes every benchmark to its fastest result
+				before averaging, so long-running entries do not outweigh short ones.
+			</p>
+
+			<section class="summary" id="summary" aria-label="Comparison summary"></section>
+
+			<section class="panel">
+				<div class="panel-heading">
+					<div>
+						<h2>Branch standings</h2>
+						<p class="help">
+							Wins count the fastest branch for each comparable entry. Normalized runtime is the
+							average slowdown against each entry's fastest result; lower is better. Click a heading
+							to sort.
+						</p>
+					</div>
+				</div>
+				<div class="table-wrap">
+					<table class="standings">
+						<thead>
+							<tr>
+								<th><button type="button" data-standing-sort="name">Branch</button></th>
+								<th><button type="button" data-standing-sort="wins">Wins</button></th>
+								<th>
+									<button type="button" data-standing-sort="score">Normalized runtime</button>
+								</th>
+							</tr>
+						</thead>
+						<tbody id="standings"></tbody>
+					</table>
+				</div>
+			</section>
+
+			<section class="panel">
+				<div class="panel-heading">
+					<div>
+						<h2>Results by benchmark</h2>
+						<p class="help">
+							Each cell shows runtime, difference from the winner, and GC time. Missing entries are
+							excluded from both standings.
+						</p>
+					</div>
+				</div>
+				<div class="controls">
+					<label
+						>Sort benchmarks
+						<select id="benchmark-sort"></select
+					></label>
+					<label
+						>Order branches
+						<select id="branch-order">
+							<option value="name">Branch name</option>
+							<option value="wins">Overall winner by wins</option>
+							<option value="score" selected>Overall winner by normalized runtime</option>
+						</select></label
+					>
+				</div>
+				<div class="table-wrap">
+					<table class="benchmark-table" id="benchmark-table"></table>
+				</div>
+			</section>
+
+			<footer id="generated"></footer>
+		</main>
+
+		<script type="application/json" id="report-data">
+			%%REPORT_DATA%%
+		</script>
+		<script>
+			const report = JSON.parse(document.querySelector('#report-data').textContent);
+			const number = new Intl.NumberFormat('en', {
+				maximumFractionDigits: 2,
+				minimumFractionDigits: 2
+			});
+			const score_number = new Intl.NumberFormat('en', {
+				maximumFractionDigits: 3,
+				minimumFractionDigits: 3
+			});
+
+			function analyze(benchmark) {
+				const complete =
+					benchmark.values.length === report.branches.length &&
+					benchmark.values.every(function (value) {
+						return value !== null && Number.isFinite(value.time) && value.time > 0;
+					});
+
+				if (!complete) return { comparable: false, min: 0, max: 0, winners: [], ratios: [] };
+
+				const times = benchmark.values.map(function (value) {
+					return value.time;
+				});
+				const min = Math.min.apply(null, times);
+				const max = Math.max.apply(null, times);
+				const winners = [];
+
+				times.forEach(function (time, index) {
+					if (time === min) winners.push(index);
+				});
+
+				return {
+					comparable: true,
+					min: min,
+					max: max,
+					winners: winners,
+					ratios: times.map(function (time) {
+						return time / min;
+					})
+				};
+			}
+
+			const analyzed = report.benchmarks.map(function (benchmark, index) {
+				return { benchmark: benchmark, stats: analyze(benchmark), index: index };
+			});
+			const comparable = analyzed.filter(function (entry) {
+				return entry.stats.comparable;
+			});
+			const standings = report.branches.map(function (name, index) {
+				let wins = 0;
+				let score = 0;
+
+				comparable.forEach(function (entry) {
+					if (entry.stats.winners.includes(index)) wins += 1;
+					score += entry.stats.ratios[index];
+				});
+
+				return {
+					name: name,
+					index: index,
+					wins: wins,
+					score: comparable.length === 0 ? Infinity : score / comparable.length
+				};
+			});
+
+			function compare_name(a, b) {
+				return a.name.localeCompare(b.name, undefined, { numeric: true });
+			}
+
+			function order_standings(key, direction) {
+				return standings.slice().sort(function (a, b) {
+					let result;
+					if (key === 'name') result = compare_name(a, b);
+					else result = a[key] - b[key];
+					return result === 0 ? compare_name(a, b) : result * direction;
+				});
+			}
+
+			function best(key, direction) {
+				const ordered = order_standings(key, direction);
+				if (ordered.length === 0) return [];
+				return ordered.filter(function (entry) {
+					return entry[key] === ordered[0][key];
+				});
+			}
+
+			function names(entries) {
+				return entries
+					.map(function (entry) {
+						return entry.name;
+					})
+					.join(', ');
+			}
+
+			function make(tag, class_name, text) {
+				const node = document.createElement(tag);
+				if (class_name) node.className = class_name;
+				if (text !== undefined) node.textContent = text;
+				return node;
+			}
+
+			const wins_best = best('wins', -1);
+			const score_best = best('score', 1);
+			const summary = document.querySelector('#summary');
+			[
+				{
+					label: 'Most benchmark wins',
+					value: comparable.length === 0 ? 'No comparable results' : names(wins_best),
+					detail:
+						comparable.length === 0
+							? ''
+							: wins_best[0].wins + ' of ' + comparable.length + ' entries'
+				},
+				{
+					label: 'Best normalized runtime',
+					value:
+						score_best.length === 0 || !Number.isFinite(score_best[0].score)
+							? 'No comparable results'
+							: names(score_best),
+					detail:
+						score_best.length === 0 || !Number.isFinite(score_best[0].score)
+							? ''
+							: score_number.format(score_best[0].score) + 'x average runtime'
+				},
+				{
+					label: 'Coverage',
+					value: comparable.length + ' comparable entries',
+					detail:
+						report.branches.length +
+						' branches, ' +
+						(report.benchmarks.length - comparable.length) +
+						' incomplete entries'
+				}
+			].forEach(function (item) {
+				const card = make('article', 'card');
+				card.append(
+					make('div', 'card-label', item.label),
+					make('div', 'card-value', item.value),
+					make('div', 'card-detail', item.detail)
+				);
+				summary.append(card);
+			});
+
+			let standing_sort = { key: 'score', direction: 1 };
+
+			function render_standings() {
+				const body = document.querySelector('#standings');
+				body.replaceChildren();
+				const score_order = order_standings('score', 1);
+
+				order_standings(standing_sort.key, standing_sort.direction).forEach(function (entry) {
+					const row = document.createElement('tr');
+					const branch = make('td');
+					branch.append(
+						make('span', 'rank', String(score_order.indexOf(entry) + 1)),
+						make('span', 'branch-name', entry.name)
+					);
+					row.append(
+						branch,
+						make('td', '', String(entry.wins)),
+						make(
+							'td',
+							'',
+							Number.isFinite(entry.score) ? score_number.format(entry.score) + 'x' : 'n/a'
+						)
+					);
+					body.append(row);
+				});
+
+				document.querySelectorAll('[data-standing-sort]').forEach(function (button) {
+					const active = button.dataset.standingSort === standing_sort.key;
+					button
+						.closest('th')
+						.setAttribute(
+							'aria-sort',
+							active ? (standing_sort.direction === 1 ? 'ascending' : 'descending') : 'none'
+						);
+					button.textContent =
+						button.dataset.standingSort === 'name'
+							? 'Branch'
+							: button.dataset.standingSort === 'wins'
+								? 'Wins'
+								: 'Normalized runtime';
+					if (active) button.textContent += standing_sort.direction === 1 ? ' ↑' : ' ↓';
+				});
+			}
+
+			document.querySelectorAll('[data-standing-sort]').forEach(function (button) {
+				button.addEventListener('click', function () {
+					const key = button.dataset.standingSort;
+					if (standing_sort.key === key) standing_sort.direction *= -1;
+					else standing_sort = { key: key, direction: key === 'wins' ? -1 : 1 };
+					render_standings();
+				});
+			});
+
+			const benchmark_sort = document.querySelector('#benchmark-sort');
+			[
+				['original', 'Original run order'],
+				['name', 'Benchmark name'],
+				['winner', 'Winner for entry'],
+				['spread', 'Largest spread']
+			]
+				.concat(
+					report.branches.map(function (branch, index) {
+						return ['branch:' + index, branch + ': slowest relative result'];
+					})
+				)
+				.forEach(function (option) {
+					const node = make('option', '', option[1]);
+					node.value = option[0];
+					benchmark_sort.append(node);
+				});
+
+			function branch_order() {
+				const key = document.querySelector('#branch-order').value;
+				if (key === 'name') return order_standings('name', 1);
+				if (key === 'wins') return order_standings('wins', -1);
+				return order_standings('score', 1);
+			}
+
+			function benchmark_order() {
+				const key = benchmark_sort.value;
+				return analyzed.slice().sort(function (a, b) {
+					if (key === 'original') return a.index - b.index;
+					if (key === 'name') return compare_name(a.benchmark, b.benchmark);
+					if (key === 'winner') {
+						const a_name = a.stats.comparable ? report.branches[a.stats.winners[0]] : '\uffff';
+						const b_name = b.stats.comparable ? report.branches[b.stats.winners[0]] : '\uffff';
+						return a_name.localeCompare(b_name) || compare_name(a.benchmark, b.benchmark);
+					}
+					if (key === 'spread') {
+						const a_spread = a.stats.comparable ? a.stats.max / a.stats.min : -1;
+						const b_spread = b.stats.comparable ? b.stats.max / b.stats.min : -1;
+						return b_spread - a_spread || compare_name(a.benchmark, b.benchmark);
+					}
+
+					const branch = Number(key.slice('branch:'.length));
+					const a_ratio = a.stats.comparable ? a.stats.ratios[branch] : -1;
+					const b_ratio = b.stats.comparable ? b.stats.ratios[branch] : -1;
+					return b_ratio - a_ratio || compare_name(a.benchmark, b.benchmark);
+				});
+			}
+
+			function render_benchmarks() {
+				const table = document.querySelector('#benchmark-table');
+				const branches = branch_order();
+				const head = document.createElement('thead');
+				const head_row = document.createElement('tr');
+				head_row.append(make('th', '', 'Benchmark'), make('th', '', 'Winner'));
+				branches.forEach(function (branch) {
+					head_row.append(make('th', '', branch.name));
+				});
+				head.append(head_row);
+
+				const body = document.createElement('tbody');
+				benchmark_order().forEach(function (entry) {
+					const row = document.createElement('tr');
+					row.append(make('td', 'benchmark-name', entry.benchmark.name));
+
+					const winner_names = entry.stats.winners.map(function (index) {
+						return report.branches[index];
+					});
+					row.append(
+						make(
+							'td',
+							winner_names.length === 0 ? 'missing' : 'winner',
+							winner_names.length === 0 ? 'Incomplete' : winner_names.join(', ')
+						)
+					);
+
+					branches.forEach(function (branch) {
+						const value = entry.benchmark.values[branch.index];
+						if (value === null || !Number.isFinite(value.time)) {
+							row.append(make('td', 'missing', 'Not available'));
+							return;
+						}
+
+						const cell = make('td', entry.stats.comparable ? 'metric' : 'missing');
+						const time = make('span', 'time', number.format(value.time) + ' ms');
+						cell.append(time);
+
+						if (entry.stats.comparable) {
+							const ratio = entry.stats.ratios[branch.index];
+							const heat =
+								entry.stats.max === entry.stats.min
+									? 0
+									: (value.time - entry.stats.min) / (entry.stats.max - entry.stats.min);
+							cell.style.setProperty('--heat', String(Math.round(142 - heat * 137)));
+							cell.append(
+								make(
+									'span',
+									'delta',
+									ratio === 1 ? 'fastest' : '+' + number.format((ratio - 1) * 100) + '%'
+								)
+							);
+						}
+
+						const gc = Number.isFinite(value.gc_time)
+							? number.format(value.gc_time) + ' ms'
+							: 'n/a';
+						cell.append(make('div', 'secondary', 'GC ' + gc));
+						row.append(cell);
+					});
+
+					body.append(row);
+				});
+
+				table.replaceChildren(head, body);
+			}
+
+			benchmark_sort.addEventListener('change', render_benchmarks);
+			document.querySelector('#branch-order').addEventListener('change', render_benchmarks);
+			document.querySelector('#generated').textContent =
+				'Generated ' + new Date(report.generated_at).toLocaleString();
+
+			render_standings();
+			render_benchmarks();
+		</script>
+	</body>
+</html>

From a91b0687866c8b2f78692010702bb811bf27b9a8 Mon Sep 17 00:00:00 2001
From: Fedor Nezhivoi <gyzerok@users.noreply.github.com>
Date: Tue, 14 Jul 2026 16:40:30 +0700
Subject: [PATCH 103/222] fix: abort deriveds own AbortSignal when it
 disconnects (#18400)

Fixes https://github.com/sveltejs/svelte/issues/18301

---------

Co-authored-by: Fedor Nezhivoi <f.nezhivoi@corp.vk.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/early-crabs-rest.md                |  5 +++++
 .../internal/client/reactivity/deriveds.js    |  9 +++++++--
 .../svelte/src/internal/client/runtime.js     |  8 ++++++++
 .../abort-signal-derived-destroy/Child.svelte | 20 +++++++++++++++++++
 .../abort-signal-derived-destroy/_config.js   | 14 +++++++++++++
 .../abort-signal-derived-destroy/main.svelte  | 14 +++++++++++++
 .../abort-signal-derived-set-state/_config.js |  2 ++
 .../main.svelte                               |  8 ++++----
 8 files changed, 74 insertions(+), 6 deletions(-)
 create mode 100644 .changeset/early-crabs-rest.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/abort-signal-derived-destroy/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/abort-signal-derived-destroy/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/abort-signal-derived-destroy/main.svelte

diff --git a/.changeset/early-crabs-rest.md b/.changeset/early-crabs-rest.md
new file mode 100644
index 0000000000..d3f290a5c2
--- /dev/null
+++ b/.changeset/early-crabs-rest.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: abort deriveds own AbortSignal when it disconnects
diff --git a/packages/svelte/src/internal/client/reactivity/deriveds.js b/packages/svelte/src/internal/client/reactivity/deriveds.js
index fd64f3b45d..6b48bc8a23 100644
--- a/packages/svelte/src/internal/client/reactivity/deriveds.js
+++ b/packages/svelte/src/internal/client/reactivity/deriveds.js
@@ -28,6 +28,7 @@ import {
 	skipped_deps,
 	new_deps
 } from '../runtime.js';
+import { without_reactive_context } from '../dom/elements/bindings/shared.js';
 import { equals, safe_equals } from './equality.js';
 import * as e from '../errors.js';
 import * as w from '../warnings.js';
@@ -450,14 +451,18 @@ export function freeze_derived_effects(derived) {
 		// if the effect has a teardown function or abort signal, call it
 		if (e.teardown || e.ac) {
 			e.teardown?.();
-			e.ac?.abort(STALE_REACTION);
+			if (e.ac !== null) {
+				without_reactive_context(() => {
+					/** @type {AbortController} */ (e.ac).abort(STALE_REACTION);
+					e.ac = null;
+				});
+			}
 
 			// make it a noop so it doesn't get called again if the derived
 			// is unfrozen. we don't set it to `null`, because the existence
 			// of a teardown function is what determines whether the
 			// effect runs again during unfreezing (but not for teardown-only effects)
 			if (e.fn !== null) e.teardown = noop;
-			e.ac = null;
 
 			remove_reactions(e, 0);
 			destroy_effect_children(e);
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 188d16a820..2ebce07916 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -408,6 +408,14 @@ function remove_reaction(signal, dependency) {
 			update_derived_status(derived);
 		}
 
+		// Call abort controller, noone's listening to this derived anymore
+		if (derived.ac !== null) {
+			without_reactive_context(() => {
+				/** @type {AbortController} */ (derived.ac).abort(STALE_REACTION);
+				derived.ac = null;
+			});
+		}
+
 		// freeze any effects inside this derived
 		freeze_derived_effects(derived);
 
diff --git a/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-destroy/Child.svelte b/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-destroy/Child.svelte
new file mode 100644
index 0000000000..5a837e5ea4
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-destroy/Child.svelte
@@ -0,0 +1,20 @@
+<script lang="ts">
+	import { getAbortSignal } from "svelte";
+
+	let { count, aborted = $bindable() } = $props()
+
+	let der = $derived.by(()=>{
+		const signal = getAbortSignal();
+
+		signal.addEventListener("abort", () => {
+			try {
+				aborted++;
+			} catch(e) {
+				console.error(e);
+			}
+		});
+		return count;
+	})
+</script>
+
+{der}
diff --git a/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-destroy/_config.js b/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-destroy/_config.js
new file mode 100644
index 0000000000..3c6ec98fe6
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-destroy/_config.js
@@ -0,0 +1,14 @@
+import { ok, test } from '../../test';
+import { flushSync } from 'svelte';
+
+export default test({
+	async test({ assert, target, errors }) {
+		const btn = target.querySelector('button');
+
+		flushSync(() => {
+			btn?.click();
+		});
+		assert.htmlEqual(target.innerHTML, '1 <button>increment</button>');
+		assert.deepEqual(errors, []);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-destroy/main.svelte b/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-destroy/main.svelte
new file mode 100644
index 0000000000..57c467a80c
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-destroy/main.svelte
@@ -0,0 +1,14 @@
+<script lang="ts">
+	import Child from './Child.svelte'
+
+	let count = $state(0);
+	let aborted = $state(0)
+</script>
+
+{aborted}
+
+<button onclick={() => count++}>increment</button>
+
+{#if count % 2 === 0}
+	<Child {count} bind:aborted={aborted} />
+{/if}
diff --git a/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-set-state/_config.js b/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-set-state/_config.js
index 2dacf188d7..aa38dd8280 100644
--- a/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-set-state/_config.js
+++ b/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-set-state/_config.js
@@ -4,9 +4,11 @@ import { flushSync } from 'svelte';
 export default test({
 	async test({ assert, target, errors }) {
 		const btn = target.querySelector('button');
+
 		flushSync(() => {
 			btn?.click();
 		});
+		assert.htmlEqual(target.innerHTML, '1:1 <button></button>');
 		assert.deepEqual(errors, []);
 	}
 });
diff --git a/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-set-state/main.svelte b/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-set-state/main.svelte
index ebefe38fb2..e76cecbac9 100644
--- a/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-set-state/main.svelte
+++ b/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-set-state/main.svelte
@@ -9,9 +9,9 @@
 		const signal = getAbortSignal();
 
 		signal.addEventListener("abort", () => {
-			try{
+			try {
 				aborted++;
-			}catch(e){
+			} catch(e) {
 				console.error(e);
 			}
 		});
@@ -19,6 +19,6 @@
 	})
 </script>
 
-{der}
+{der}:{aborted}
 
-<button onclick={() => count++}></button>
\ No newline at end of file
+<button onclick={() => count++}></button>

From edeef1f9f713ab1ffdba698ff6d92cce8da1c5b4 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Tue, 14 Jul 2026 11:41:20 +0200
Subject: [PATCH 104/222] chore: add some failing tests (#18528)

During my explorations I collected these new tests which are currently
failing. Two of them work on the incremental-batches branch, all of them
(adjusted for new behavior) pass on my uncommitted entangle batches
branch, and all of them also pass on another uncommitted experimental
branch of overlaying deriveds which will likely not land.
---
 .../_config.js                                | 42 +++++++++++++++++++
 .../main.svelte                               | 23 ++++++++++
 .../async-derived-not-overfiring/_config.js   | 35 ++++++++++++++++
 .../async-derived-not-overfiring/main.svelte  | 29 +++++++++++++
 .../async-derived-not-underfiring/_config.js  | 28 +++++++++++++
 .../async-derived-not-underfiring/main.svelte | 22 ++++++++++
 6 files changed, 179 insertions(+)
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-derived-log-outside-reactivity/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-derived-log-outside-reactivity/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-derived-not-overfiring/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-derived-not-overfiring/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-derived-not-underfiring/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-derived-not-underfiring/main.svelte

diff --git a/packages/svelte/tests/runtime-runes/samples/async-derived-log-outside-reactivity/_config.js b/packages/svelte/tests/runtime-runes/samples/async-derived-log-outside-reactivity/_config.js
new file mode 100644
index 0000000000..1a7ed0eb92
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-derived-log-outside-reactivity/_config.js
@@ -0,0 +1,42 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	skip: true, // TODO fix
+	async test({ assert, target, logs }) {
+		await tick();
+
+		const [a, b, log, resolve] = target.querySelectorAll('button');
+		const [p] = target.querySelectorAll('p');
+
+		a.click();
+		await tick();
+		assert.htmlEqual(p.innerHTML, '0 0 0');
+
+		b.click();
+		await tick();
+		assert.htmlEqual(p.innerHTML, '0 0 0');
+
+		log.click();
+		await tick();
+		assert.deepEqual(logs, [0, 2]);
+
+		resolve.click();
+		await tick();
+		assert.htmlEqual(p.innerHTML, '1 0 1');
+		assert.deepEqual(logs, [0, 2, 1]);
+
+		log.click();
+		await tick();
+		assert.deepEqual(logs, [0, 2, 1, 2]);
+
+		resolve.click();
+		await tick();
+		assert.htmlEqual(p.innerHTML, '1 1 2');
+		assert.deepEqual(logs, [0, 2, 1, 2, 2]);
+
+		log.click();
+		await tick();
+		assert.deepEqual(logs, [0, 2, 1, 2, 2, 2]);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-derived-log-outside-reactivity/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-derived-log-outside-reactivity/main.svelte
new file mode 100644
index 0000000000..bf543ba595
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-derived-log-outside-reactivity/main.svelte
@@ -0,0 +1,23 @@
+<script>
+	let a = $state(0);
+	let b = $state(0);
+
+	let d = $derived(a + b);
+
+	let queued = [];
+	function push(v) {
+		if (!v) return v;
+		return new Promise((resolve) => {
+			queued.push(() => resolve(v));
+		});
+	}
+
+	$effect(() => console.log(d));
+</script>
+
+<button onclick={() => a++}>a++</button>
+<button onclick={() => b++}>b++</button>
+<button onclick={() => console.log(d)}>log d</button>
+<button onclick={() => queued.shift()?.()}>resolve</button>
+
+<p>{await push(a)} {await push(b)} {d}</p>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-derived-not-overfiring/_config.js b/packages/svelte/tests/runtime-runes/samples/async-derived-not-overfiring/_config.js
new file mode 100644
index 0000000000..b959ba5407
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-derived-not-overfiring/_config.js
@@ -0,0 +1,35 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	skip: true, // TODO fix
+	async test({ assert, target, logs }) {
+		await tick();
+
+		const [a, b, log, resolve] = target.querySelectorAll('button');
+		const [div] = target.querySelectorAll('div');
+
+		assert.deepEqual(logs, ['e1 0', 'e2 0']);
+		logs.length = 0;
+
+		a.click();
+		await tick();
+		assert.htmlEqual(div.innerHTML, '<p>0</p> <p>0</p> <p>0</p>');
+
+		b.click();
+		await tick();
+		assert.htmlEqual(div.innerHTML, '<p>0</p> <p>1</p> <p>1</p>');
+
+		log.click();
+		await tick();
+		assert.deepEqual(logs, ['e1 1', 'e2 1', 'runs 2']); // ideally it's only 2 runs, one or two more would also be acceptable but not the 8 that it's today
+		logs.length = 0;
+
+		resolve.click();
+		await tick();
+		log.click();
+		await tick();
+		assert.htmlEqual(div.innerHTML, '<p>1</p> <p>2</p> <p>2</p>');
+		assert.deepEqual(logs, ['e1 2', 'e2 2', 'runs 3']);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-derived-not-overfiring/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-derived-not-overfiring/main.svelte
new file mode 100644
index 0000000000..784932ab5d
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-derived-not-overfiring/main.svelte
@@ -0,0 +1,29 @@
+<script>
+	let a = $state(0);
+	let b = $state(0);
+	let runs = 0;
+
+	let d = $derived((runs++, a + b));
+
+	const queued = [];
+	function push(v) {
+		if (!v) return v;
+		return new Promise((resolve) => {
+			queued.push(() => resolve(v));
+		});
+	}
+
+	$effect(() => console.log('e1 ' + d));
+	$effect(() => console.log('e2 ' + d));
+</script>
+
+<button onclick={() => a++}>a++</button>
+<button onclick={() => b++}>b++</button>
+<button onclick={() => console.log('runs ' + runs)}>log runs</button>
+<button onclick={() => queued.shift()?.()}>resolve</button>
+
+<div>
+	<p>{await push(a)}</p>
+	<p>{d}</p>
+	<p>{d}</p>
+</div>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-derived-not-underfiring/_config.js b/packages/svelte/tests/runtime-runes/samples/async-derived-not-underfiring/_config.js
new file mode 100644
index 0000000000..7d31d30b46
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-derived-not-underfiring/_config.js
@@ -0,0 +1,28 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	skip: true, // TODO fix
+	async test({ assert, target, logs }) {
+		await tick();
+
+		const [a, b, resolve] = target.querySelectorAll('button');
+		const [p] = target.querySelectorAll('p');
+
+		assert.deepEqual(logs, ['b: 0, d: 0']);
+		logs.length = 0;
+
+		a.click();
+		await tick();
+		b.click();
+		await tick();
+		assert.htmlEqual(p.innerHTML, '0 1');
+		assert.deepEqual(logs, ['b: 1, d: 0']);
+		logs.length = 0;
+
+		resolve.click();
+		await tick();
+		assert.htmlEqual(p.innerHTML, '2 1');
+		assert.deepEqual(logs, ['b: 1, d: 2']);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-derived-not-underfiring/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-derived-not-underfiring/main.svelte
new file mode 100644
index 0000000000..97d91ae994
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-derived-not-underfiring/main.svelte
@@ -0,0 +1,22 @@
+<script>
+	let a = $state(0);
+	let b = $state(0);
+
+	let d = $derived(a * 2);
+
+	const queued = [];
+	function push(v) {
+		if (!v) return v;
+		return new Promise((resolve) => {
+			queued.push(() => resolve(v));
+		});
+	}
+
+	$effect(() => console.log(`b: ${b}, d: ${d}`));
+</script>
+
+<button onclick={() => a++}>a++</button>
+<button onclick={() => b++}>b++</button>
+<button onclick={() => queued.shift()?.()}>resolve</button>
+
+<p>{await push(d)} {b}</p>

From 199ffebca375b29b65fcac53fc1825b452175a53 Mon Sep 17 00:00:00 2001
From: prashantg-pixi <prashant.g@zvky.com>
Date: Tue, 14 Jul 2026 15:21:13 +0530
Subject: [PATCH 105/222] fix: clear previous_task reference after abort in
 Tween (#18541)

avoids memory leaks
---
 .changeset/tween-previous-task-leak.md | 5 +++++
 packages/svelte/src/motion/tweened.js  | 1 +
 2 files changed, 6 insertions(+)
 create mode 100644 .changeset/tween-previous-task-leak.md

diff --git a/.changeset/tween-previous-task-leak.md b/.changeset/tween-previous-task-leak.md
new file mode 100644
index 0000000000..6208e7c87a
--- /dev/null
+++ b/.changeset/tween-previous-task-leak.md
@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+fix: clear previous_task reference after abort in Tween to prevent memory leak on interrupted tweens
diff --git a/packages/svelte/src/motion/tweened.js b/packages/svelte/src/motion/tweened.js
index a24148d075..460db0df64 100644
--- a/packages/svelte/src/motion/tweened.js
+++ b/packages/svelte/src/motion/tweened.js
@@ -275,6 +275,7 @@ export class Tween {
 				}
 
 				previous_task?.abort();
+				previous_task = null;
 			}
 
 			const elapsed = now - start;

From a4fd67e361914df612ae432ff75283c2d332ae18 Mon Sep 17 00:00:00 2001
From: adiGuba <frederic.martini@gmail.com>
Date: Tue, 14 Jul 2026 11:54:13 +0200
Subject: [PATCH 106/222] fix: $state.eager() is sometimes incorrect in SSR
 (#18530)

Fix #18529

A simple fix : `context.visit()` was missing on the argument of
`$state.eager()`, so the generated code can be incorrect in some case :
---
 .changeset/long-buttons-hunt.md                            | 5 +++++
 .../phases/3-transform/server/visitors/CallExpression.js   | 2 +-
 .../samples/state-eager/_expected.html                     | 2 ++
 .../server-side-rendering/samples/state-eager/main.svelte  | 7 +++++++
 4 files changed, 15 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/long-buttons-hunt.md
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/state-eager/_expected.html
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/state-eager/main.svelte

diff --git a/.changeset/long-buttons-hunt.md b/.changeset/long-buttons-hunt.md
new file mode 100644
index 0000000000..68d0b60ff4
--- /dev/null
+++ b/.changeset/long-buttons-hunt.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: ensure `$state.eager()` is correctly transormed for SSR output
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/CallExpression.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/CallExpression.js
index 8525fb6366..ac78f55da9 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/CallExpression.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/CallExpression.js
@@ -46,7 +46,7 @@ export function CallExpression(node, context) {
 	}
 
 	if (rune === '$state.eager') {
-		return node.arguments[0];
+		return context.visit(node.arguments[0]);
 	}
 
 	if (rune === '$state.snapshot') {
diff --git a/packages/svelte/tests/server-side-rendering/samples/state-eager/_expected.html b/packages/svelte/tests/server-side-rendering/samples/state-eager/_expected.html
new file mode 100644
index 0000000000..9d3ea2f5b4
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/state-eager/_expected.html
@@ -0,0 +1,2 @@
+<div>value=0</div>
+<div>eager=0</div>
\ No newline at end of file
diff --git a/packages/svelte/tests/server-side-rendering/samples/state-eager/main.svelte b/packages/svelte/tests/server-side-rendering/samples/state-eager/main.svelte
new file mode 100644
index 0000000000..d144914f72
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/state-eager/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	let props = $props();
+	const value = $derived(props.number ?? 0);
+</script>
+
+<div>value={value}</div>
+<div>eager={$state.eager(value)}</div>

From 602a873b6b82bba4e6edc91b039e2f6defbe3fc4 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Tue, 14 Jul 2026 13:59:06 +0200
Subject: [PATCH 107/222] Version Packages (#18497)

This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.


# Releases
## svelte@5.56.5

### Patch Changes

- chore: drop dead code that make TSGO fail
([#18496](https://github.com/sveltejs/svelte/pull/18496))

- fix: don't (re)connect deriveds when read inside branch/root effects
([#18527](https://github.com/sveltejs/svelte/pull/18527))

- fix: skip unnecessary derived effect in earlier batch
([#18525](https://github.com/sveltejs/svelte/pull/18525))

- fix: avoid declaration tag warning in event handlers
([#18500](https://github.com/sveltejs/svelte/pull/18500))

- fix: abort deriveds own AbortSignal when it disconnects
([#18400](https://github.com/sveltejs/svelte/pull/18400))

- fix: ensure `$state.eager()` is correctly transormed for SSR output
([#18530](https://github.com/sveltejs/svelte/pull/18530))

- fix: correctly transform declaration tags during SSR
([#18492](https://github.com/sveltejs/svelte/pull/18492))

- fix: transform computed keys in keyed `{#each}` destructuring patterns
([#18521](https://github.com/sveltejs/svelte/pull/18521))

- fix: chain preprocessor sourcemaps with an empty `sources[0]` instead
of dropping them
([#18518](https://github.com/sveltejs/svelte/pull/18518))

- fix: clear previous_task reference after abort in Tween to prevent
memory leak on interrupted tweens
([#18541](https://github.com/sveltejs/svelte/pull/18541))

- fix: don't treat declaration tags as parts inside each blocks
([#18507](https://github.com/sveltejs/svelte/pull/18507))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/big-months-shout.md         |  5 -----
 .changeset/common-ways-deny.md         |  5 -----
 .changeset/curly-wasps-hide.md         |  5 -----
 .changeset/dull-oranges-fry.md         |  5 -----
 .changeset/early-crabs-rest.md         |  5 -----
 .changeset/long-buttons-hunt.md        |  5 -----
 .changeset/rich-jokes-attack.md        |  5 -----
 .changeset/shiny-keys-dance.md         |  5 -----
 .changeset/tame-donkeys-jump.md        |  5 -----
 .changeset/tween-previous-task-leak.md |  5 -----
 .changeset/young-doodles-beam.md       |  5 -----
 packages/svelte/CHANGELOG.md           | 26 ++++++++++++++++++++++++++
 packages/svelte/package.json           |  2 +-
 packages/svelte/src/version.js         |  2 +-
 14 files changed, 28 insertions(+), 57 deletions(-)
 delete mode 100644 .changeset/big-months-shout.md
 delete mode 100644 .changeset/common-ways-deny.md
 delete mode 100644 .changeset/curly-wasps-hide.md
 delete mode 100644 .changeset/dull-oranges-fry.md
 delete mode 100644 .changeset/early-crabs-rest.md
 delete mode 100644 .changeset/long-buttons-hunt.md
 delete mode 100644 .changeset/rich-jokes-attack.md
 delete mode 100644 .changeset/shiny-keys-dance.md
 delete mode 100644 .changeset/tame-donkeys-jump.md
 delete mode 100644 .changeset/tween-previous-task-leak.md
 delete mode 100644 .changeset/young-doodles-beam.md

diff --git a/.changeset/big-months-shout.md b/.changeset/big-months-shout.md
deleted file mode 100644
index 3d8ca0045e..0000000000
--- a/.changeset/big-months-shout.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-chore: drop dead code that make TSGO fail
diff --git a/.changeset/common-ways-deny.md b/.changeset/common-ways-deny.md
deleted file mode 100644
index 75e9375965..0000000000
--- a/.changeset/common-ways-deny.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: don't (re)connect deriveds when read inside branch/root effects
diff --git a/.changeset/curly-wasps-hide.md b/.changeset/curly-wasps-hide.md
deleted file mode 100644
index 7e55d77ba0..0000000000
--- a/.changeset/curly-wasps-hide.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: skip unnecessary derived effect in earlier batch
diff --git a/.changeset/dull-oranges-fry.md b/.changeset/dull-oranges-fry.md
deleted file mode 100644
index 0efcc6fa2d..0000000000
--- a/.changeset/dull-oranges-fry.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: avoid declaration tag warning in event handlers
diff --git a/.changeset/early-crabs-rest.md b/.changeset/early-crabs-rest.md
deleted file mode 100644
index d3f290a5c2..0000000000
--- a/.changeset/early-crabs-rest.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: abort deriveds own AbortSignal when it disconnects
diff --git a/.changeset/long-buttons-hunt.md b/.changeset/long-buttons-hunt.md
deleted file mode 100644
index 68d0b60ff4..0000000000
--- a/.changeset/long-buttons-hunt.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: ensure `$state.eager()` is correctly transormed for SSR output
diff --git a/.changeset/rich-jokes-attack.md b/.changeset/rich-jokes-attack.md
deleted file mode 100644
index 46e7d2d8c8..0000000000
--- a/.changeset/rich-jokes-attack.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: correctly transform declaration tags during SSR
diff --git a/.changeset/shiny-keys-dance.md b/.changeset/shiny-keys-dance.md
deleted file mode 100644
index 20cf754212..0000000000
--- a/.changeset/shiny-keys-dance.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: transform computed keys in keyed `{#each}` destructuring patterns
diff --git a/.changeset/tame-donkeys-jump.md b/.changeset/tame-donkeys-jump.md
deleted file mode 100644
index aae38910db..0000000000
--- a/.changeset/tame-donkeys-jump.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: chain preprocessor sourcemaps with an empty `sources[0]` instead of dropping them
diff --git a/.changeset/tween-previous-task-leak.md b/.changeset/tween-previous-task-leak.md
deleted file mode 100644
index 6208e7c87a..0000000000
--- a/.changeset/tween-previous-task-leak.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-"svelte": patch
----
-
-fix: clear previous_task reference after abort in Tween to prevent memory leak on interrupted tweens
diff --git a/.changeset/young-doodles-beam.md b/.changeset/young-doodles-beam.md
deleted file mode 100644
index b68f55d241..0000000000
--- a/.changeset/young-doodles-beam.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: don't treat declaration tags as parts inside each blocks
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 80b61facb0..d80da025c9 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,31 @@
 # svelte
 
+## 5.56.5
+
+### Patch Changes
+
+- chore: drop dead code that make TSGO fail ([#18496](https://github.com/sveltejs/svelte/pull/18496))
+
+- fix: don't (re)connect deriveds when read inside branch/root effects ([#18527](https://github.com/sveltejs/svelte/pull/18527))
+
+- fix: skip unnecessary derived effect in earlier batch ([#18525](https://github.com/sveltejs/svelte/pull/18525))
+
+- fix: avoid declaration tag warning in event handlers ([#18500](https://github.com/sveltejs/svelte/pull/18500))
+
+- fix: abort deriveds own AbortSignal when it disconnects ([#18400](https://github.com/sveltejs/svelte/pull/18400))
+
+- fix: ensure `$state.eager()` is correctly transormed for SSR output ([#18530](https://github.com/sveltejs/svelte/pull/18530))
+
+- fix: correctly transform declaration tags during SSR ([#18492](https://github.com/sveltejs/svelte/pull/18492))
+
+- fix: transform computed keys in keyed `{#each}` destructuring patterns ([#18521](https://github.com/sveltejs/svelte/pull/18521))
+
+- fix: chain preprocessor sourcemaps with an empty `sources[0]` instead of dropping them ([#18518](https://github.com/sveltejs/svelte/pull/18518))
+
+- fix: clear previous_task reference after abort in Tween to prevent memory leak on interrupted tweens ([#18541](https://github.com/sveltejs/svelte/pull/18541))
+
+- fix: don't treat declaration tags as parts inside each blocks ([#18507](https://github.com/sveltejs/svelte/pull/18507))
+
 ## 5.56.4
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 34fa68c8a7..a26a3e4a76 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.56.4",
+  "version": "5.56.5",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index ef468a2f79..80b38c225a 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.56.4';
+export const VERSION = '5.56.5';
 export const PUBLIC_VERSION = '5';

From 22e0adb75a07442015feb0465cee1d3a61729e90 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Thu, 16 Jul 2026 10:42:31 +0200
Subject: [PATCH 108/222] fix: rerun derived that had an abort controller on
 reconnection (#18551)

Follow-up to #18400 - we need to mark a derived with an abort signal
that is frozen as dirty so it is guaranteed to rerun when it
reconnects/is re-requested. Else you could return a stale value, or
worse, you returned a promise from the derived which you aborted, and
it's now in the rejected state until you update one of its dependencies.
---
 .changeset/lucky-dolls-yell.md                |  5 +++
 .../svelte/src/internal/client/runtime.js     |  2 ++
 .../_config.js                                | 32 +++++++++++++++++++
 .../main.svelte                               | 32 +++++++++++++++++++
 4 files changed, 71 insertions(+)
 create mode 100644 .changeset/lucky-dolls-yell.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/abort-signal-derived-rerun-on-reconnect/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/abort-signal-derived-rerun-on-reconnect/main.svelte

diff --git a/.changeset/lucky-dolls-yell.md b/.changeset/lucky-dolls-yell.md
new file mode 100644
index 0000000000..d158f376d1
--- /dev/null
+++ b/.changeset/lucky-dolls-yell.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: rerun derived that had an abort controller on reconnection
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 2ebce07916..4458595d35 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -413,6 +413,8 @@ function remove_reaction(signal, dependency) {
 			without_reactive_context(() => {
 				/** @type {AbortController} */ (derived.ac).abort(STALE_REACTION);
 				derived.ac = null;
+				// ensure it reruns right away next time instead of potentially returning a rejected promise as its value
+				set_signal_status(derived, DIRTY);
 			});
 		}
 
diff --git a/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-rerun-on-reconnect/_config.js b/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-rerun-on-reconnect/_config.js
new file mode 100644
index 0000000000..7caf765e3b
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-rerun-on-reconnect/_config.js
@@ -0,0 +1,32 @@
+import { test } from '../../test';
+import { tick } from 'svelte';
+
+export default test({
+	async test({ assert, target }) {
+		const [increment, toggle, resolve] = target.querySelectorAll('button');
+		const [div] = target.querySelectorAll('div');
+
+		assert.htmlEqual(div.innerHTML, 'loading');
+		resolve.click();
+		await tick();
+		assert.htmlEqual(div.innerHTML, '0');
+
+		increment.click();
+		await tick();
+		assert.htmlEqual(div.innerHTML, 'loading');
+
+		toggle.click();
+		await tick();
+		assert.htmlEqual(div.innerHTML, '');
+
+		toggle.click();
+		await tick();
+		assert.htmlEqual(div.innerHTML, 'loading');
+
+		resolve.click(); // this one's for clearing the obsolete/aborted one from the queue
+		await tick();
+		resolve.click();
+		await tick();
+		assert.htmlEqual(div.innerHTML, '2');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-rerun-on-reconnect/main.svelte b/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-rerun-on-reconnect/main.svelte
new file mode 100644
index 0000000000..a047afdd44
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/abort-signal-derived-rerun-on-reconnect/main.svelte
@@ -0,0 +1,32 @@
+<script>
+	import { getAbortSignal } from 'svelte'
+	
+	let show = $state(true)
+	let count = $state(0);
+	let queued = [];
+
+	export function sleep(value, signal) {
+	  return new Promise((resolve, reject) => {
+	    signal.addEventListener('abort', reject, { once: true });
+		queued.push(() => resolve(value));
+	  });
+	}
+
+	const double = $derived(sleep(count * 2, getAbortSignal()));
+</script>
+
+<button onclick={() => count += 1}>clicks: {count}</button>
+<button onclick={() => show = !show}>toggle</button>
+<button onclick={() => queued.shift()?.()}>resolve</button>
+
+<div>
+	{#if show}
+		{#await double}
+			loading
+		{:then value}
+			{value}
+		{:catch}
+			error
+		{/await}
+	{/if}
+</div>

From d0dbe1a48013b9c405b518511f8330baf3a27bc9 Mon Sep 17 00:00:00 2001
From: Joe Schafer <joe.schafer@delta46.us>
Date: Thu, 16 Jul 2026 04:35:37 -0700
Subject: [PATCH 109/222] perf: skip quadratic blocker analysis when no
 top-level await (#18548)

Skip function reference tracing in `calculate_blockers` when a component
has no top-level `await`.

Blockers only represent dependencies on top-level async statements.
Without a top-level `await`, no binding can have a blocker, so tracing
every top-level function cannot affect the generated output. In large
components with many functions and transitive assignments, that
unnecessary work can become quadratic.
---
 .changeset/fast-cats-compile.md                        | 5 +++++
 packages/svelte/src/compiler/phases/2-analyze/index.js | 4 ++++
 2 files changed, 9 insertions(+)
 create mode 100644 .changeset/fast-cats-compile.md

diff --git a/.changeset/fast-cats-compile.md b/.changeset/fast-cats-compile.md
new file mode 100644
index 0000000000..585ce0ed1d
--- /dev/null
+++ b/.changeset/fast-cats-compile.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+perf: skip unnecessary blocker analysis when compiling components without top-level await
diff --git a/packages/svelte/src/compiler/phases/2-analyze/index.js b/packages/svelte/src/compiler/phases/2-analyze/index.js
index ef20049697..67e9030188 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/index.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/index.js
@@ -1221,6 +1221,10 @@ function calculate_blockers(instance, analysis) {
 		}
 	}
 
+	// With no top-level await, no binding can have a blocker and function tracing
+	// cannot affect the output.
+	if (!awaited) return;
+
 	flush_sync_group();
 
 	for (const fn of functions) {

From 4a6a85b5f149cc96514ed3bf5e59083b9246d394 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Fri, 17 Jul 2026 00:21:52 +0200
Subject: [PATCH 110/222] Version Packages (#18552)

This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.


# Releases
## svelte@5.56.6

### Patch Changes

- perf: skip unnecessary blocker analysis when compiling components
without top-level await
([#18548](https://github.com/sveltejs/svelte/pull/18548))

- fix: rerun derived that had an abort controller on reconnection
([#18551](https://github.com/sveltejs/svelte/pull/18551))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/fast-cats-compile.md | 5 -----
 .changeset/lucky-dolls-yell.md  | 5 -----
 packages/svelte/CHANGELOG.md    | 8 ++++++++
 packages/svelte/package.json    | 2 +-
 packages/svelte/src/version.js  | 2 +-
 5 files changed, 10 insertions(+), 12 deletions(-)
 delete mode 100644 .changeset/fast-cats-compile.md
 delete mode 100644 .changeset/lucky-dolls-yell.md

diff --git a/.changeset/fast-cats-compile.md b/.changeset/fast-cats-compile.md
deleted file mode 100644
index 585ce0ed1d..0000000000
--- a/.changeset/fast-cats-compile.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-perf: skip unnecessary blocker analysis when compiling components without top-level await
diff --git a/.changeset/lucky-dolls-yell.md b/.changeset/lucky-dolls-yell.md
deleted file mode 100644
index d158f376d1..0000000000
--- a/.changeset/lucky-dolls-yell.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: rerun derived that had an abort controller on reconnection
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index d80da025c9..0f26b571d3 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,13 @@
 # svelte
 
+## 5.56.6
+
+### Patch Changes
+
+- perf: skip unnecessary blocker analysis when compiling components without top-level await ([#18548](https://github.com/sveltejs/svelte/pull/18548))
+
+- fix: rerun derived that had an abort controller on reconnection ([#18551](https://github.com/sveltejs/svelte/pull/18551))
+
 ## 5.56.5
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index a26a3e4a76..855ba92a8d 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.56.5",
+  "version": "5.56.6",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 80b38c225a..05d88ef904 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.56.5';
+export const VERSION = '5.56.6';
 export const PUBLIC_VERSION = '5';

From b791cac54e2db43317f2bc6c8e41e694245c551e Mon Sep 17 00:00:00 2001
From: Manuel <30698007+manuel3108@users.noreply.github.com>
Date: Sat, 18 Jul 2026 14:47:30 +0200
Subject: [PATCH 111/222] chore: provide `indent` option for `print` (#18474)

Relevant for https://github.com/sveltejs/cli/pull/1138.
This is basically just an option from `esrap` that we pass through. That
will allow tools like `sv migrate` to provide a guessed indent based on
the other file contents and therefore allow us to produce way smaller
diffs. Since we are just passing an option, there is no need for a test
here.

Technically a `feat:` but i dont think this is relevant enough.

### Before submitting the PR, please make sure you do the following

- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [ ] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).

### Tests and linting

- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
---
 .changeset/short-otters-find.md               | 5 +++++
 packages/svelte/src/compiler/print/index.js   | 5 ++++-
 packages/svelte/src/compiler/print/types.d.ts | 1 +
 packages/svelte/types/index.d.ts              | 1 +
 4 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/short-otters-find.md

diff --git a/.changeset/short-otters-find.md b/.changeset/short-otters-find.md
new file mode 100644
index 0000000000..57194653b6
--- /dev/null
+++ b/.changeset/short-otters-find.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+chore: provide `indent` option for `print`
diff --git a/packages/svelte/src/compiler/print/index.js b/packages/svelte/src/compiler/print/index.js
index fbd7e86f12..a5fbc96fc8 100644
--- a/packages/svelte/src/compiler/print/index.js
+++ b/packages/svelte/src/compiler/print/index.js
@@ -30,7 +30,10 @@ export function print(ast, options = undefined) {
 			}),
 			...svelte_visitors(comments),
 			...css_visitors
-		})
+		}),
+		{
+			indent: options?.indent
+		}
 	);
 }
 
diff --git a/packages/svelte/src/compiler/print/types.d.ts b/packages/svelte/src/compiler/print/types.d.ts
index d0ff909525..9eccebb6f3 100644
--- a/packages/svelte/src/compiler/print/types.d.ts
+++ b/packages/svelte/src/compiler/print/types.d.ts
@@ -4,4 +4,5 @@ import type ts from 'esrap/languages/ts';
 export type Options = {
 	getLeadingComments?: NonNullable<Parameters<typeof ts>[0]>['getLeadingComments'] | undefined;
 	getTrailingComments?: NonNullable<Parameters<typeof ts>[0]>['getTrailingComments'] | undefined;
+	indent?: string; // default tab
 };
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index 5f41fabf60..d758022ae4 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -1854,6 +1854,7 @@ declare module 'svelte/compiler' {
 	type Options = {
 		getLeadingComments?: NonNullable<Parameters<typeof ts>[0]>['getLeadingComments'] | undefined;
 		getTrailingComments?: NonNullable<Parameters<typeof ts>[0]>['getTrailingComments'] | undefined;
+		indent?: string; // default tab
 	};
 
 	export {};

From d9e40d17cf751e22dbc3ec42b9cb50920e2d1229 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Sat, 18 Jul 2026 21:00:02 -0400
Subject: [PATCH 112/222] docs: update link on hooks page (#18564)

this docs page updated recently and broke everything
---
 documentation/docs/05-special-elements/01-svelte-boundary.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/documentation/docs/05-special-elements/01-svelte-boundary.md b/documentation/docs/05-special-elements/01-svelte-boundary.md
index e1ad00a50b..41ebee1564 100644
--- a/documentation/docs/05-special-elements/01-svelte-boundary.md
+++ b/documentation/docs/05-special-elements/01-svelte-boundary.md
@@ -109,7 +109,7 @@ By default, error boundaries have no effect on the server — if an error occurs
 
 Since 5.51 you can control this behaviour for boundaries with a `failed` snippet, by calling [`render(...)`](imperative-component-api#render) with a `transformError` function.
 
-> [!NOTE] If you're using Svelte via a framework such as SvelteKit, you most likely don't have direct access to the `render(...)` call — the framework must configure `transformError` on your behalf. SvelteKit will add support for this in the near future, via the [`handleError`](../kit/hooks#Shared-hooks-handleError) hook.
+> [!NOTE] If you're using Svelte via a framework such as SvelteKit, you most likely don't have direct access to the `render(...)` call — the framework must configure `transformError` on your behalf. SvelteKit will add support for this in the near future, via the [`handleError`](../kit/hooks#handleError) hook.
 
 The `transformError` function must return a JSON-stringifiable object which will be used to render the `failed` snippet. This object will be serialized and used to hydrate the snippet in the browser:
 

From b29d7002ecf9bc0036b18647c0b7677a7cb0a914 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Mon, 20 Jul 2026 15:23:49 -0400
Subject: [PATCH 113/222] Version Packages (#18560)

This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.


# Releases
## svelte@5.56.7

### Patch Changes

- chore: provide `indent` option for `print`
([#18474](https://github.com/sveltejs/svelte/pull/18474))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/short-otters-find.md | 5 -----
 packages/svelte/CHANGELOG.md    | 6 ++++++
 packages/svelte/package.json    | 2 +-
 packages/svelte/src/version.js  | 2 +-
 4 files changed, 8 insertions(+), 7 deletions(-)
 delete mode 100644 .changeset/short-otters-find.md

diff --git a/.changeset/short-otters-find.md b/.changeset/short-otters-find.md
deleted file mode 100644
index 57194653b6..0000000000
--- a/.changeset/short-otters-find.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-chore: provide `indent` option for `print`
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 0f26b571d3..a9b93f5341 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,11 @@
 # svelte
 
+## 5.56.7
+
+### Patch Changes
+
+- chore: provide `indent` option for `print` ([#18474](https://github.com/sveltejs/svelte/pull/18474))
+
 ## 5.56.6
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 855ba92a8d..67f349be71 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.56.6",
+  "version": "5.56.7",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 05d88ef904..e9737ec13c 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.56.6';
+export const VERSION = '5.56.7';
 export const PUBLIC_VERSION = '5';

From 2bace308e37ac1def958be750bd699ed302bb715 Mon Sep 17 00:00:00 2001
From: Floze <88098863+floze-the-genius@users.noreply.github.com>
Date: Wed, 22 Jul 2026 16:17:27 +0400
Subject: [PATCH 114/222] fix: preserve select selection with spread attributes
 (#18561)

Fixes #18557

A `<select>` with spread attributes initializes the option mutation
observer even when those attributes never provide a `value`. In that
case the element has no internal `__value`, but the observer previously
treated the missing property as an explicit `undefined` value and
deselected every option after an option was added or removed.

Only reapply the programmatic selection when `__value` is actually
present. This preserves the browser's current selection for spreads
without a value while keeping the existing behavior for bindings,
including an explicitly stored `undefined` value.

A runtime-legacy regression fixture covers both adding and removing an
option in client and hydration modes.

### Before submitting

- [x] References the existing issue
- [x] Uses a `fix:` title
- [x] Includes a regression test
- [x] Includes a patch changeset for `svelte`

### Test plan

- [x] `FILTER=select-spread-preserve-selection pnpm test runtime-legacy
--maxWorkers=1` (2 tests passed: client and hydrate)
- [x] `git diff --check`
- [ ] Full `pnpm test` was not run because the shared host was under
resource pressure and broad test processes were explicitly avoided
- [ ] `pnpm lint` and `pnpm check` were not run for the same reason
- [ ] Targeted repository Prettier check was attempted, but could not
start because `prettier-plugin-svelte` required the ungenerated
`packages/svelte/compiler/index.js`; no broad build or dependency
reinstall was run

### AI disclosure

AI-assisted: the implementation, regression test, and pull request text
were prepared with OpenAI Codex and reviewed by the contributor.

Co-authored-by: Paolo Ricciuti <ricciutipaolo@gmail.com>
---
 .changeset/tidy-select-spreads.md             |  5 ++++
 .../client/dom/elements/bindings/select.js    |  6 +++--
 .../_config.js                                | 25 +++++++++++++++++++
 .../main.svelte                               | 16 ++++++++++++
 4 files changed, 50 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/tidy-select-spreads.md
 create mode 100644 packages/svelte/tests/runtime-legacy/samples/select-spread-preserve-selection/_config.js
 create mode 100644 packages/svelte/tests/runtime-legacy/samples/select-spread-preserve-selection/main.svelte

diff --git a/.changeset/tidy-select-spreads.md b/.changeset/tidy-select-spreads.md
new file mode 100644
index 0000000000..3b14dc5d34
--- /dev/null
+++ b/.changeset/tidy-select-spreads.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: preserve select selection when spread attributes omit value
diff --git a/packages/svelte/src/internal/client/dom/elements/bindings/select.js b/packages/svelte/src/internal/client/dom/elements/bindings/select.js
index eb26062653..e390e23ea0 100644
--- a/packages/svelte/src/internal/client/dom/elements/bindings/select.js
+++ b/packages/svelte/src/internal/client/dom/elements/bindings/select.js
@@ -56,8 +56,10 @@ export function select_option(select, value, mounting = false) {
  */
 export function init_select(select) {
 	var observer = new MutationObserver(() => {
-		// @ts-ignore
-		select_option(select, select.__value);
+		if ('__value' in select) {
+			// @ts-ignore
+			select_option(select, select.__value);
+		}
 		// Deliberately don't update the potential binding value,
 		// the model should be preserved unless explicitly changed
 	});
diff --git a/packages/svelte/tests/runtime-legacy/samples/select-spread-preserve-selection/_config.js b/packages/svelte/tests/runtime-legacy/samples/select-spread-preserve-selection/_config.js
new file mode 100644
index 0000000000..8bc2f11e26
--- /dev/null
+++ b/packages/svelte/tests/runtime-legacy/samples/select-spread-preserve-selection/_config.js
@@ -0,0 +1,25 @@
+import { flushSync } from 'svelte';
+import { ok, test } from '../../test';
+
+export default test({
+	mode: ['client', 'hydrate'],
+
+	async test({ assert, component, target }) {
+		const select = target.querySelector('select');
+		ok(select);
+
+		assert.equal(select.selectedIndex, 0);
+
+		component.toggle();
+		flushSync();
+		await Promise.resolve();
+
+		assert.equal(select.selectedIndex, 0);
+
+		component.toggle();
+		flushSync();
+		await Promise.resolve();
+
+		assert.equal(select.selectedIndex, 0);
+	}
+});
diff --git a/packages/svelte/tests/runtime-legacy/samples/select-spread-preserve-selection/main.svelte b/packages/svelte/tests/runtime-legacy/samples/select-spread-preserve-selection/main.svelte
new file mode 100644
index 0000000000..229ce4fb73
--- /dev/null
+++ b/packages/svelte/tests/runtime-legacy/samples/select-spread-preserve-selection/main.svelte
@@ -0,0 +1,16 @@
+<script>
+	let show_extra = false;
+	const attributes = { 'aria-label': 'choice' };
+
+	export function toggle() {
+		show_extra = !show_extra;
+	}
+</script>
+
+<select {...attributes}>
+	<option value="">Choose an option</option>
+	<option value="first">First</option>
+	{#if show_extra}
+		<option value="extra">Extra</option>
+	{/if}
+</select>

From 3dde011d3a9e7b9145169da0b75dcd607a378c0e Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Thu, 23 Jul 2026 17:45:50 -0400
Subject: [PATCH 115/222] fix: call `onerror` and provide a working `reset`
 when hydrating a failed boundary (#18556)

Fixes #18555

A boundary that failed during SSR hydrates via
`#hydrate_failed_content`, which never calls `onerror` and passes the
`failed` snippet a no-op `reset`. Both came in with #17672, whose docs
say `onerror` "will be called upon hydration with the deserialized error
object". Once hydrated as failed, the boundary can never leave that
state. Downstream this is what keeps SvelteKit's `+error.svelte` mounted
after navigating away from a server-rendered error page
(sveltejs/kit#16345).

This extracts the reset/onerror machinery from `#handle_error` into
`#create_reset` and uses it in the hydration path too. `onerror` is
invoked in a microtask because it may mutate state, which is disallowed
while hydrating. `#handle_error` already invokes it asynchronously, so
the timing matches the error path.

The tests flip a `recovered` flag before calling `reset`, since the
child would otherwise throw again. That is the intended retry pattern,
and the same one kit uses when it resets route boundaries on navigation.
Verified against kit end to end, hydrating a server-rendered error page
and navigating away now tears it down with no kit changes needed.
---
 .changeset/hydrated-boundary-reset.md         |  5 ++
 .../internal/client/dom/blocks/boundary.js    | 89 ++++++++++++-------
 .../error-boundary-hydrate-1/_config.js       | 19 ++++
 .../error-boundary-hydrate-1/child.svelte     |  3 +
 .../error-boundary-hydrate-1/main.svelte      | 29 ++++++
 .../error-boundary-hydrate-2/_config.js       | 16 ++++
 .../error-boundary-hydrate-2/child.svelte     |  3 +
 .../error-boundary-hydrate-2/main.svelte      | 22 +++++
 8 files changed, 152 insertions(+), 34 deletions(-)
 create mode 100644 .changeset/hydrated-boundary-reset.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-1/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-1/child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-1/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-2/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-2/child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-2/main.svelte

diff --git a/.changeset/hydrated-boundary-reset.md b/.changeset/hydrated-boundary-reset.md
new file mode 100644
index 0000000000..799a57fd9b
--- /dev/null
+++ b/.changeset/hydrated-boundary-reset.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: call `onerror` and provide a working `reset` when hydrating a failed boundary
diff --git a/packages/svelte/src/internal/client/dom/blocks/boundary.js b/packages/svelte/src/internal/client/dom/blocks/boundary.js
index 0c0903ff52..4f655a3695 100644
--- a/packages/svelte/src/internal/client/dom/blocks/boundary.js
+++ b/packages/svelte/src/internal/client/dom/blocks/boundary.js
@@ -199,17 +199,68 @@ export class Boundary {
 	 */
 	#hydrate_failed_content(error) {
 		const failed = this.#props.failed;
+		const { reset, invoke_onerror } = this.#create_reset(error);
+
+		// `onerror` may mutate state, which is disallowed while hydrating
+		queue_micro_task(invoke_onerror);
+
 		if (!failed) return;
 
 		this.#failed_effect = branch(() => {
 			failed(
 				this.#anchor,
 				() => error,
-				() => () => {}
+				() => reset
 			);
 		});
 	}
 
+	/**
+	 * Creates the `reset` function for a failed boundary, along with a function
+	 * that invokes `onerror` with it (if provided)
+	 * @param {unknown} error
+	 * @returns {{ reset: () => void, invoke_onerror: () => void }}
+	 */
+	#create_reset(error) {
+		var did_reset = false;
+		var calling_on_error = false;
+
+		const reset = () => {
+			if (did_reset) {
+				w.svelte_boundary_reset_noop();
+				return;
+			}
+
+			did_reset = true;
+
+			if (calling_on_error) {
+				e.svelte_boundary_reset_onerror();
+			}
+
+			if (this.#failed_effect !== null) {
+				pause_effect(this.#failed_effect, () => {
+					this.#failed_effect = null;
+				});
+			}
+
+			this.#run(() => {
+				this.#render();
+			});
+		};
+
+		const invoke_onerror = () => {
+			try {
+				calling_on_error = true;
+				this.#props.onerror?.(error, reset);
+				calling_on_error = false;
+			} catch (err) {
+				invoke_error_boundary(err, this.#effect && this.#effect.parent);
+			}
+		};
+
+		return { reset, invoke_onerror };
+	}
+
 	#hydrate_pending_content() {
 		const pending = this.#props.pending;
 		if (!pending) return;
@@ -429,43 +480,13 @@ export class Boundary {
 			set_hydrate_node(skip_nodes());
 		}
 
-		var onerror = this.#props.onerror;
 		let failed = this.#props.failed;
-		var did_reset = false;
-		var calling_on_error = false;
-
-		const reset = () => {
-			if (did_reset) {
-				w.svelte_boundary_reset_noop();
-				return;
-			}
-
-			did_reset = true;
-
-			if (calling_on_error) {
-				e.svelte_boundary_reset_onerror();
-			}
-
-			if (this.#failed_effect !== null) {
-				pause_effect(this.#failed_effect, () => {
-					this.#failed_effect = null;
-				});
-			}
-
-			this.#run(() => {
-				this.#render();
-			});
-		};
 
 		/** @param {unknown} transformed_error */
 		const handle_error_result = (transformed_error) => {
-			try {
-				calling_on_error = true;
-				onerror?.(transformed_error, reset);
-				calling_on_error = false;
-			} catch (error) {
-				invoke_error_boundary(error, this.#effect && this.#effect.parent);
-			}
+			const { reset, invoke_onerror } = this.#create_reset(transformed_error);
+
+			invoke_onerror();
 
 			if (failed) {
 				this.#failed_effect = this.#run(() => {
diff --git a/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-1/_config.js b/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-1/_config.js
new file mode 100644
index 0000000000..f0aef7e92f
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-1/_config.js
@@ -0,0 +1,19 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['hydrate'],
+	ssrHtml: '<p>failed: error</p> <button>reset</button>',
+	transformError: () => 'error',
+
+	test({ assert, target, logs }) {
+		// `onerror` is called upon hydration with the deserialized error
+		assert.deepEqual(logs, ['onerror: error']);
+
+		const btn = target.querySelector('button');
+		btn?.click();
+		flushSync();
+
+		assert.htmlEqual(target.innerHTML, '<p>recovered</p> <button>reset</button>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-1/child.svelte b/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-1/child.svelte
new file mode 100644
index 0000000000..e93c7bb0fa
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-1/child.svelte
@@ -0,0 +1,3 @@
+<script>
+	throw new Error('unlucky');
+</script>
diff --git a/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-1/main.svelte b/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-1/main.svelte
new file mode 100644
index 0000000000..e84198473b
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-1/main.svelte
@@ -0,0 +1,29 @@
+<script>
+	import Child from './child.svelte';
+
+	let recovered = $state(false);
+	let reset_fn = $state();
+</script>
+
+<svelte:boundary
+	onerror={(error, reset) => {
+		console.log(`onerror: ${error}`);
+		reset_fn = reset;
+	}}
+>
+	{#if recovered}
+		<p>recovered</p>
+	{:else}
+		<Child />
+	{/if}
+
+	{#snippet failed(error)}
+		<p>failed: {error}</p>
+	{/snippet}
+</svelte:boundary>
+
+<button
+	onclick={() => {
+		recovered = true;
+		reset_fn();
+	}}>reset</button>
diff --git a/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-2/_config.js b/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-2/_config.js
new file mode 100644
index 0000000000..e5c52eb19c
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-2/_config.js
@@ -0,0 +1,16 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['hydrate'],
+	ssrHtml: '<p>failed: error</p> <button>reset</button>',
+	transformError: () => 'error',
+
+	test({ assert, target }) {
+		const btn = target.querySelector('button');
+		btn?.click();
+		flushSync();
+
+		assert.htmlEqual(target.innerHTML, '<p>recovered</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-2/child.svelte b/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-2/child.svelte
new file mode 100644
index 0000000000..e93c7bb0fa
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-2/child.svelte
@@ -0,0 +1,3 @@
+<script>
+	throw new Error('unlucky');
+</script>
diff --git a/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-2/main.svelte b/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-2/main.svelte
new file mode 100644
index 0000000000..1642a94e7a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/error-boundary-hydrate-2/main.svelte
@@ -0,0 +1,22 @@
+<script>
+	import Child from './child.svelte';
+
+	let recovered = $state(false);
+</script>
+
+<svelte:boundary>
+	{#if recovered}
+		<p>recovered</p>
+	{:else}
+		<Child />
+	{/if}
+
+	{#snippet failed(error, reset)}
+		<p>failed: {error}</p>
+		<button
+			onclick={() => {
+				recovered = true;
+				reset();
+			}}>reset</button>
+	{/snippet}
+</svelte:boundary>

From 23bc246a99c649c0c325509debb93e062948e240 Mon Sep 17 00:00:00 2001
From: Elliott Johnson <hello@ell.iott.dev>
Date: Fri, 24 Jul 2026 14:14:11 -0600
Subject: [PATCH 116/222] chore: Supply chain hardening (#18253)

`svelte`

Supply-chain hardening pass.

## Changes
- Bump `packageManager` from `pnpm@10.4.0` to `pnpm@10.33.4` with
`+sha512` integrity suffix.
- Add to `pnpm-workspace.yaml`:
  - `minimumReleaseAge: 1440`
  - `minimumReleaseAgeExclude: ['@sveltejs/*', svelte, esrap, devalue]`
  - `blockExoticSubdeps: true`
- Remove `pkg.pr.new.yml` workflow in favor of `pkg.svelte.dev`
- Pin all third-party GitHub Actions to full SHA with `# vX.Y.Z`
comments across `ci.yml`, `autofix.yml`, `release.yml`,
`ecosystem-ci-trigger.yml`
- Upgrade `pnpm/action-setup` references in `ci.yml`, `autofix.yml`,
`release.yml` from a SHA that was incorrectly labeled `# v4` (actually
`v5.0.0` / `v4.4.0`) to the current `v6.0.8` SHA so the version label
matches reality.
---
 .github/workflows/autofix.yml              |   8 +-
 .github/workflows/ci.yml                   |  30 +--
 .github/workflows/ecosystem-ci-trigger.yml |   8 +-
 .github/workflows/pkg.pr.new.yml           | 229 ---------------------
 .github/workflows/release.yml              |   6 +-
 package.json                               |   2 +-
 pnpm-workspace.yaml                        |  12 ++
 7 files changed, 39 insertions(+), 256 deletions(-)
 delete mode 100644 .github/workflows/pkg.pr.new.yml

diff --git a/.github/workflows/autofix.yml b/.github/workflows/autofix.yml
index b6c26e0792..5cdbd34e5b 100644
--- a/.github/workflows/autofix.yml
+++ b/.github/workflows/autofix.yml
@@ -28,7 +28,7 @@ jobs:
       - name: Get PR ref
         if: github.event_name != 'workflow_dispatch'
         id: pr
-        uses: actions/github-script@v8
+        uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8
         with:
           script: |
             const { data: pull } = await github.rest.pulls.get({
@@ -46,12 +46,12 @@ jobs:
               core.setFailed('PR is from a fork');
             }
             core.setOutput('ref', pull.head.ref);
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
         if: github.event_name == 'workflow_dispatch' || steps.pr.outcome == 'success'
         with:
           ref: ${{ github.event_name == 'workflow_dispatch' && github.ref || steps.pr.outputs.ref }}
-      - uses: pnpm/action-setup@b906affcce14559ad1aafd4ab0e942779e9f58b1 # v4.3.0
-      - uses: actions/setup-node@v6
+      - uses: pnpm/action-setup@0e279bb959325dab635dd2c09392533439d90093 # v6.0.8
+      - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6
         with:
           node-version: 24
           cache: pnpm
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 365717755e..3846690135 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -32,9 +32,9 @@ jobs:
             os: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v6
-      - uses: pnpm/action-setup@fc06bc1257f339d1d5d8b3a19a8cae5388b55320 # v4
-      - uses: actions/setup-node@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+      - uses: pnpm/action-setup@0e279bb959325dab635dd2c09392533439d90093 # v6.0.8
+      - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6
         with:
           node-version: ${{ matrix.node-version }}
           cache: pnpm
@@ -48,9 +48,9 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 10
     steps:
-      - uses: actions/checkout@v6
-      - uses: pnpm/action-setup@fc06bc1257f339d1d5d8b3a19a8cae5388b55320 # v4
-      - uses: actions/setup-node@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+      - uses: pnpm/action-setup@0e279bb959325dab635dd2c09392533439d90093 # v6.0.8
+      - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6
         with:
           node-version: 22
           cache: pnpm
@@ -65,9 +65,9 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:
-      - uses: actions/checkout@v6
-      - uses: pnpm/action-setup@fc06bc1257f339d1d5d8b3a19a8cae5388b55320 # v4
-      - uses: actions/setup-node@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+      - uses: pnpm/action-setup@0e279bb959325dab635dd2c09392533439d90093 # v6.0.8
+      - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6
         with:
           node-version: 24
           cache: pnpm
@@ -82,9 +82,9 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 10
     steps:
-      - uses: actions/checkout@v6
-      - uses: pnpm/action-setup@fc06bc1257f339d1d5d8b3a19a8cae5388b55320 # v4
-      - uses: actions/setup-node@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+      - uses: pnpm/action-setup@0e279bb959325dab635dd2c09392533439d90093 # v6.0.8
+      - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6
         with:
           node-version: 24
           cache: pnpm
@@ -105,9 +105,9 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 15
     steps:
-      - uses: actions/checkout@v6
-      - uses: pnpm/action-setup@fc06bc1257f339d1d5d8b3a19a8cae5388b55320 # v4
-      - uses: actions/setup-node@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+      - uses: pnpm/action-setup@0e279bb959325dab635dd2c09392533439d90093 # v6.0.8
+      - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6
         with:
           node-version: 24
           cache: pnpm
diff --git a/.github/workflows/ecosystem-ci-trigger.yml b/.github/workflows/ecosystem-ci-trigger.yml
index 8a6d1bf345..8691a64ca4 100644
--- a/.github/workflows/ecosystem-ci-trigger.yml
+++ b/.github/workflows/ecosystem-ci-trigger.yml
@@ -17,7 +17,7 @@ jobs:
       contents: read # to clone the repo
     steps:
       - name: Check User Permissions
-        uses: actions/github-script@v8
+        uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8
         id: check-permissions
         with:
           script: |
@@ -56,7 +56,7 @@ jobs:
             }
 
       - name: Get PR Data
-        uses: actions/github-script@v8
+        uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8
         id: get-pr-data
         with:
           script: |
@@ -106,7 +106,7 @@ jobs:
 
       - name: Generate Token
         id: generate-token
-        uses: actions/create-github-app-token@v2
+        uses: actions/create-github-app-token@fee1f7d63c2ff003460e3d139729b119787bc349 # v2
         with:
           app-id: ${{ secrets.ECOSYSTEM_CI_GITHUB_APP_ID }}
           private-key: ${{ secrets.ECOSYSTEM_CI_GITHUB_APP_PRIVATE_KEY }}
@@ -115,7 +115,7 @@ jobs:
             svelte-ecosystem-ci
 
       - name: Trigger Downstream Workflow
-        uses: actions/github-script@v8
+        uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8
         id: trigger
         env:
           COMMENT: ${{ github.event.comment.body }}
diff --git a/.github/workflows/pkg.pr.new.yml b/.github/workflows/pkg.pr.new.yml
deleted file mode 100644
index 0fcda5a778..0000000000
--- a/.github/workflows/pkg.pr.new.yml
+++ /dev/null
@@ -1,229 +0,0 @@
-name: pkg.pr.new
-on:
-  pull_request_target:
-    types: [opened, synchronize]
-  push:
-    branches: [main]
-  workflow_dispatch:
-    inputs:
-      sha:
-        description: 'Commit SHA to build'
-        required: true
-        type: string
-      pr:
-        description: 'PR number to comment on'
-        required: true
-        type: number
-
-permissions: {}
-
-jobs:
-  build:
-    # Skip pull_request_target events from forks — maintainers can use workflow_dispatch instead
-    if: >
-      github.event_name != 'pull_request_target' ||
-      github.event.pull_request.head.repo.full_name == github.repository
-    runs-on: ubuntu-latest
-    # No permissions — this job runs user-controlled code
-    permissions: {}
-
-    steps:
-      - uses: actions/checkout@v6
-        with:
-          # For pull_request_target, check out the PR head.
-          # For workflow_dispatch, check out the manually specified SHA.
-          # For push, fall back to the push SHA.
-          ref: ${{ github.event.pull_request.head.sha || inputs.sha || github.sha }}
-
-      - uses: pnpm/action-setup@fc06bc1257f339d1d5d8b3a19a8cae5388b55320 # v4
-      - uses: actions/setup-node@v6
-        with:
-          node-version: 22.x
-          cache: pnpm
-
-      - name: Install dependencies
-        run: pnpm install --frozen-lockfile
-
-      - name: Build
-        run: pnpm build
-
-      - run: pnpx pkg-pr-new publish --comment=off --json output.json --compact --no-template './packages/svelte'
-
-      - name: Upload output
-        uses: actions/upload-artifact@v4
-        with:
-          name: output
-          path: ./output.json
-
-  # Sanitizes the untrusted output from the build job before it's consumed by
-  # jobs with elevated permissions. This ensures that only known package names
-  # and valid SHA prefixes make it through.
-  sanitize:
-    needs: build
-    runs-on: ubuntu-latest
-
-    permissions: {}
-
-    steps:
-      - name: Download artifact
-        uses: actions/download-artifact@v7
-        with:
-          name: output
-
-      - name: Sanitize output
-        uses: actions/github-script@v8
-        with:
-          script: |
-            const fs = require('fs');
-            const raw = JSON.parse(fs.readFileSync('output.json', 'utf8'));
-
-            const ALLOWED_PACKAGES = new Set(['svelte']);
-            const SHA_PATTERN = /^[0-9a-f]{7}$/;
-
-            const packages = (raw.packages || [])
-              .filter(p => {
-                if (!ALLOWED_PACKAGES.has(p.name)) {
-                  console.log(`Skipping unexpected package: ${JSON.stringify(p.name)}`);
-                  return false;
-                }
-                const sha = p.url?.replace(/^.+@([^@]+)$/, '$1');
-                if (!sha || !SHA_PATTERN.test(sha)) {
-                  console.log(`Skipping package with invalid SHA: ${JSON.stringify(p.url)}`);
-                  return false;
-                }
-                return true;
-              })
-              .map(p => ({
-                name: p.name,
-                sha: p.url.replace(/^.+@([^@]+)$/, '$1'),
-              }));
-
-            fs.writeFileSync('sanitized-output.json', JSON.stringify({ packages }), 'utf8');
-
-      - name: Upload sanitized output
-        uses: actions/upload-artifact@v4
-        with:
-          name: sanitized-output
-          path: ./sanitized-output.json
-
-  comment:
-    needs: sanitize
-    if: github.event_name == 'pull_request_target' || github.event_name == 'workflow_dispatch'
-    runs-on: ubuntu-latest
-
-    permissions:
-      contents: read
-      pull-requests: write
-
-    steps:
-      - name: Download sanitized artifact
-        uses: actions/download-artifact@v7
-        with:
-          name: sanitized-output
-
-      - name: Resolve PR number
-        id: pr
-        uses: actions/github-script@v8
-        with:
-          script: |
-            if (context.eventName === 'pull_request_target') {
-              core.setOutput('number', context.issue.number);
-              return;
-            }
-
-            // For workflow_dispatch, use the explicitly provided PR number.
-            // We can't use listPullRequestsAssociatedWithCommit because fork
-            // commits don't exist in the base repo, so the API returns nothing.
-            const pr = Number('${{ inputs.pr }}');
-            if (!pr || isNaN(pr)) {
-              core.setFailed('workflow_dispatch requires a valid pr input');
-              return;
-            }
-
-            core.setOutput('number', pr);
-
-      - name: Post or update comment
-        uses: actions/github-script@v8
-        with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}
-          script: |
-            const fs = require('fs');
-            const { packages } = JSON.parse(fs.readFileSync('sanitized-output.json', 'utf8'));
-
-            if (packages.length === 0) {
-              console.log('No valid packages found. Skipping comment.');
-              return;
-            }
-
-            const issue_number = parseInt('${{ steps.pr.outputs.number }}', 10);
-
-            const bot_comment_identifier = `<!-- pkg.pr.new comment -->`;
-
-            const body = `${bot_comment_identifier}
-
-            [Playground](https://svelte.dev/playground?version=pr-${issue_number})
-
-            \`\`\`
-            ${packages.map(p => `pnpm add https://pkg.pr.new/${p.name}@${issue_number}`).join('\n')}
-            \`\`\`
-            `;
-
-            const comments = await github.rest.issues.listComments({
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              issue_number,
-            });
-            const existing = comments.data.find(c => c.body.includes(bot_comment_identifier));
-
-            if (existing) {
-              await github.rest.issues.updateComment({
-                owner: context.repo.owner,
-                repo: context.repo.repo,
-                comment_id: existing.id,
-                body,
-              });
-            } else {
-              await github.rest.issues.createComment({
-                owner: context.repo.owner,
-                repo: context.repo.repo,
-                issue_number,
-                body,
-              });
-            }
-
-  log:
-    needs: sanitize
-    if: github.event_name == 'push'
-    runs-on: ubuntu-latest
-
-    permissions: {}
-
-    steps:
-      - name: Download sanitized artifact
-        uses: actions/download-artifact@v7
-        with:
-          name: sanitized-output
-
-      - name: Log publish info
-        uses: actions/github-script@v8
-        with:
-          script: |
-            const fs = require('fs');
-            const { packages } = JSON.parse(fs.readFileSync('sanitized-output.json', 'utf8'));
-
-            if (packages.length === 0) {
-              console.log('No valid packages found.');
-              return;
-            }
-
-            console.log('\n' + '='.repeat(50));
-            console.log('Publish Information');
-            console.log('='.repeat(50));
-            for (const p of packages) {
-              console.log(`${p.name} - pnpm add https://pkg.pr.new/${p.name}@${p.sha}`);
-            }
-            const svelte = packages.find(p => p.name === 'svelte');
-            if (svelte) {
-              console.log(`\nPlayground: https://svelte.dev/playground?version=commit-${svelte.sha}`);
-            }
-            console.log('='.repeat(50));
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 359fcb7eea..12fe17582e 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -23,13 +23,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
         with:
           # This makes Actions fetch all Git history so that Changesets can generate changelogs with the correct commits
           fetch-depth: 0
-      - uses: pnpm/action-setup@fc06bc1257f339d1d5d8b3a19a8cae5388b55320 # v4
+      - uses: pnpm/action-setup@0e279bb959325dab635dd2c09392533439d90093 # v6.0.8
       - name: Setup Node.js
-        uses: actions/setup-node@v6
+        uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6
         with:
           node-version: 24.x
           cache: pnpm
diff --git a/package.json b/package.json
index 0d2fbc7fd6..a178d31698 100644
--- a/package.json
+++ b/package.json
@@ -5,7 +5,7 @@
   "private": true,
   "type": "module",
   "license": "MIT",
-  "packageManager": "pnpm@10.4.0",
+  "packageManager": "pnpm@10.33.4+sha512.1c67b3b359b2d408119ba1ed289f34b8fc3c6873412bec6fd264fbdc82489e510fcbecb9ce9d22dae7f3b76269d8441046014bdca53b9979cd7a561ad631b800",
   "engines": {
     "pnpm": ">=9.0.0"
   },
diff --git a/pnpm-workspace.yaml b/pnpm-workspace.yaml
index f94dac7cc7..8c81497078 100644
--- a/pnpm-workspace.yaml
+++ b/pnpm-workspace.yaml
@@ -1,3 +1,15 @@
+minimumReleaseAge: 2880
+minimumReleaseAgeExclude:
+  - '@sveltejs/*'
+  - svelte
+  - esrap
+  - devalue
+  - zimmerframe
+  - prettier-plugin-svelte
+  - svelte-check
+  - esm-env
+blockExoticSubdeps: true
+
 packages:
   - 'packages/*'
   - 'playgrounds/*'

From 44a7813730579b94004e182e5a67aab27aa9d2a6 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Sat, 25 Jul 2026 00:04:41 +0200
Subject: [PATCH 117/222] Version Packages (#18572)

This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.


# Releases
## svelte@5.56.8

### Patch Changes

- fix: call `onerror` and provide a working `reset` when hydrating a
failed boundary
([#18556](https://github.com/sveltejs/svelte/pull/18556))

- fix: preserve select selection when spread attributes omit value
([#18561](https://github.com/sveltejs/svelte/pull/18561))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/hydrated-boundary-reset.md | 5 -----
 .changeset/tidy-select-spreads.md     | 5 -----
 packages/svelte/CHANGELOG.md          | 8 ++++++++
 packages/svelte/package.json          | 2 +-
 packages/svelte/src/version.js        | 2 +-
 5 files changed, 10 insertions(+), 12 deletions(-)
 delete mode 100644 .changeset/hydrated-boundary-reset.md
 delete mode 100644 .changeset/tidy-select-spreads.md

diff --git a/.changeset/hydrated-boundary-reset.md b/.changeset/hydrated-boundary-reset.md
deleted file mode 100644
index 799a57fd9b..0000000000
--- a/.changeset/hydrated-boundary-reset.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: call `onerror` and provide a working `reset` when hydrating a failed boundary
diff --git a/.changeset/tidy-select-spreads.md b/.changeset/tidy-select-spreads.md
deleted file mode 100644
index 3b14dc5d34..0000000000
--- a/.changeset/tidy-select-spreads.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: preserve select selection when spread attributes omit value
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index a9b93f5341..722fc21052 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,13 @@
 # svelte
 
+## 5.56.8
+
+### Patch Changes
+
+- fix: call `onerror` and provide a working `reset` when hydrating a failed boundary ([#18556](https://github.com/sveltejs/svelte/pull/18556))
+
+- fix: preserve select selection when spread attributes omit value ([#18561](https://github.com/sveltejs/svelte/pull/18561))
+
 ## 5.56.7
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 67f349be71..82dd4faf61 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.56.7",
+  "version": "5.56.8",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index e9737ec13c..8fb86f3398 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.56.7';
+export const VERSION = '5.56.8';
 export const PUBLIC_VERSION = '5';

From 26786e92985842a6d563c67049a43bc5857bf792 Mon Sep 17 00:00:00 2001
From: Sankalp Thakur <31366524+sankalpsthakur@users.noreply.github.com>
Date: Sat, 8 Aug 2026 01:07:07 +0530
Subject: [PATCH 118/222] fix: skip controlled each fast path while another
 batch is pending (#18625)

Fixes #18610

### Problem

In async mode, a controlled keyed `{#each}` throws `TypeError: Cannot
read properties of undefined (reading 'e')` when its collection becomes
empty while an earlier batch is still pending on the same block.

The fast path in `pause_effects` cleared `state.items` and then called
`destroy_effects`, which walks pending batch keys and reads
`state.items.get(key).e`. Those EachItems are still needed for the
pending batch (preserved offscreen), so clearing the map makes the
dereference throw and aborts the commit mid-flight.

### Fix

Only take the controlled-each fast path when `state.pending.size === 0`,
so pending batches keep their items until they commit or discard.
---
 .changeset/async-each-controlled-pending.md   |  5 ++
 .../src/internal/client/dom/blocks/each.js    |  8 ++-
 .../_config.js                                | 50 +++++++++++++++++
 .../main.svelte                               | 54 +++++++++++++++++++
 4 files changed, 115 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/async-each-controlled-pending.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-each-controlled-empty-pending/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-each-controlled-empty-pending/main.svelte

diff --git a/.changeset/async-each-controlled-pending.md b/.changeset/async-each-controlled-pending.md
new file mode 100644
index 0000000000..c37f914d13
--- /dev/null
+++ b/.changeset/async-each-controlled-pending.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: skip controlled each fast path while another batch is pending
diff --git a/packages/svelte/src/internal/client/dom/blocks/each.js b/packages/svelte/src/internal/client/dom/blocks/each.js
index 2df1d6ffa1..9a2504f887 100644
--- a/packages/svelte/src/internal/client/dom/blocks/each.js
+++ b/packages/svelte/src/internal/client/dom/blocks/each.js
@@ -103,8 +103,12 @@ function pause_effects(state, to_destroy, controlled_anchor) {
 	if (remaining === 0) {
 		// If we're in a controlled each block (i.e. the block is the only child of an
 		// element), and we are removing all items, _and_ there are no out transitions,
-		// we can use the fast path — emptying the element and replacing the anchor
-		var fast_path = transitions.length === 0 && controlled_anchor !== null;
+		// we can use the fast path — emptying the element and replacing the anchor.
+		// Skip the fast path when another batch is still pending on this each block:
+		// that batch's keys still reference EachItems in `state.items`, which
+		// `destroy_effects` needs to preserve offscreen (see #18610).
+		var fast_path =
+			transitions.length === 0 && controlled_anchor !== null && state.pending.size === 0;
 
 		if (fast_path) {
 			var anchor = /** @type {Element} */ (controlled_anchor);
diff --git a/packages/svelte/tests/runtime-runes/samples/async-each-controlled-empty-pending/_config.js b/packages/svelte/tests/runtime-runes/samples/async-each-controlled-empty-pending/_config.js
new file mode 100644
index 0000000000..29d374deec
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-each-controlled-empty-pending/_config.js
@@ -0,0 +1,50 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+// Regression for #18610: emptying a controlled keyed {#each} while another
+// batch is still pending must not take the fast path that clears state.items
+// before destroy_effects walks pending keys.
+export default test({
+	mode: ['client'],
+
+	async test({ assert, target }) {
+		await tick();
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>startA</button>
+				<button>startB</button>
+				<button>settleB</button>
+				<p>A0/B0</p>
+				<div><span>1</span><span>2</span></div>
+			`
+		);
+
+		const [startA, startB, settleB] = target.querySelectorAll('button');
+
+		// Batch A: add key 9, then block forever on gate A.
+		startA.click();
+		await tick();
+
+		// Batch B: empty the collection, then block on gate B.
+		startB.click();
+		await tick();
+
+		// Settle B first so B commits while A is still pending.
+		// Without the fix this throws reading `.e` of undefined and leaves a/b stuck.
+		settleB.click();
+		await tick();
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>startA</button>
+				<button>startB</button>
+				<button>settleB</button>
+				<p>A0/B1</p>
+				<div></div>
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-each-controlled-empty-pending/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-each-controlled-empty-pending/main.svelte
new file mode 100644
index 0000000000..68c3937c25
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-each-controlled-empty-pending/main.svelte
@@ -0,0 +1,54 @@
+<script>
+	let base = $state([1, 2]);
+	let extraKey = $state(/** @type {number | null} */ (null));
+	let tickA = $state(0);
+	let tickB = $state(0);
+
+	// Two independent sources so the batches touch disjoint source sets
+	// and are not merged.
+	const items = $derived(extraKey === null ? base : [...base, extraKey]);
+
+	/** @type {((value: string) => void) | undefined} */
+	let resolveB;
+
+	/**
+	 * @param {string} name
+	 * @param {number} n
+	 */
+	const gate = (name, n) =>
+		n === 0
+			? Promise.resolve(`${name}0`)
+			: new Promise((r) => {
+					if (name === 'B') resolveB = r;
+				});
+
+	const a = $derived(await gate('A', tickA));
+	const b = $derived(await gate('B', tickB));
+
+	function startA() {
+		extraKey = 9;
+		tickA = 1;
+	}
+
+	function startB() {
+		base = [];
+		tickB = 1;
+	}
+
+	function settleB() {
+		resolveB?.('B1');
+	}
+</script>
+
+<button onclick={startA}>startA</button>
+<button onclick={startB}>startB</button>
+<button onclick={settleB}>settleB</button>
+
+<p>{a}/{b}</p>
+
+<!-- Sole child so the each block is controlled and the fast path applies. -->
+<div>
+	{#each items as item (item)}
+		<span>{item}</span>
+	{/each}
+</div>

From 3ed9db4ba78f61792b875b7651755a9c0a018037 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Wed, 12 Aug 2026 17:40:28 +0200
Subject: [PATCH 119/222] fix: don't duplicate comments in attributes (#18636)

An attribute with a comment would be printed again atop the following
attribute because we didn't take that case into account.
---
 .changeset/modern-otters-pick.md               |  5 +++++
 packages/svelte/src/compiler/print/index.js    | 18 ++++++++++++------
 .../comment-inside-attribute/input.svelte      |  7 +++++++
 .../comment-inside-attribute/output.svelte     |  7 +++++++
 4 files changed, 31 insertions(+), 6 deletions(-)
 create mode 100644 .changeset/modern-otters-pick.md
 create mode 100644 packages/svelte/tests/print/samples/comment-inside-attribute/input.svelte
 create mode 100644 packages/svelte/tests/print/samples/comment-inside-attribute/output.svelte

diff --git a/.changeset/modern-otters-pick.md b/.changeset/modern-otters-pick.md
new file mode 100644
index 0000000000..de5803e19f
--- /dev/null
+++ b/.changeset/modern-otters-pick.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: don't duplicate comments in attributes
diff --git a/packages/svelte/src/compiler/print/index.js b/packages/svelte/src/compiler/print/index.js
index a5fbc96fc8..fe76f31ad3 100644
--- a/packages/svelte/src/compiler/print/index.js
+++ b/packages/svelte/src/compiler/print/index.js
@@ -82,6 +82,7 @@ function attributes(node, attributes, context, comments) {
 	}
 
 	const separator = context.new();
+	let previous_attribute_end = node.start;
 
 	const children = attributes.map((attribute) => {
 		const child_context = context.new();
@@ -90,12 +91,16 @@ function attributes(node, attributes, context, comments) {
 			const comment = comments[comment_index];
 
 			if (comment.start < attribute.start) {
-				if (comment.type === 'Line') {
-					child_context.write('//' + comment.value);
-					child_context.newline();
-				} else {
-					child_context.write('/*' + comment.value + '*/'); // TODO match indentation?
-					child_context.append(separator);
+				// Inside a previous attribute's value can be comments which don't
+				// advance comment_index, therefore this additional check
+				if (comment.start >= previous_attribute_end) {
+					if (comment.type === 'Line') {
+						child_context.write('//' + comment.value);
+						child_context.newline();
+					} else {
+						child_context.write('/*' + comment.value + '*/'); // TODO match indentation?
+						child_context.append(separator);
+					}
 				}
 
 				comment_index += 1;
@@ -105,6 +110,7 @@ function attributes(node, attributes, context, comments) {
 		}
 
 		child_context.visit(attribute);
+		previous_attribute_end = attribute.end;
 
 		length += child_context.measure() + 1;
 
diff --git a/packages/svelte/tests/print/samples/comment-inside-attribute/input.svelte b/packages/svelte/tests/print/samples/comment-inside-attribute/input.svelte
new file mode 100644
index 0000000000..4575abf75a
--- /dev/null
+++ b/packages/svelte/tests/print/samples/comment-inside-attribute/input.svelte
@@ -0,0 +1,7 @@
+<Button
+	onclick={() => {
+		// belongs to onclick
+		run();
+	}}
+	onkeydown={() => run()}
+/>
diff --git a/packages/svelte/tests/print/samples/comment-inside-attribute/output.svelte b/packages/svelte/tests/print/samples/comment-inside-attribute/output.svelte
new file mode 100644
index 0000000000..4575abf75a
--- /dev/null
+++ b/packages/svelte/tests/print/samples/comment-inside-attribute/output.svelte
@@ -0,0 +1,7 @@
+<Button
+	onclick={() => {
+		// belongs to onclick
+		run();
+	}}
+	onkeydown={() => run()}
+/>

From a1d5035d1777be6ab177d3749668f599ccefc445 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Wed, 12 Aug 2026 19:13:47 +0200
Subject: [PATCH 120/222] fix: preserve CSS comments in the AST printer
 (#18637)

Adds a new `comments` array to the stylesheet node which CSS comments
are added to. Is subsequently used in `print` to see them in the output.

Alternative to #18475
---
 .changeset/soft-cats-comment.md               |   5 +
 packages/svelte/src/compiler/index.js         |   3 +-
 .../src/compiler/phases/1-parse/index.js      |   4 +
 .../src/compiler/phases/1-parse/read/style.js |  82 ++--
 .../phases/2-analyze/css/css-analyze.js       |   3 +
 .../compiler/phases/2-analyze/css/css-warn.js |   3 +
 .../compiler/phases/3-transform/css/index.js  |   3 +
 packages/svelte/src/compiler/print/index.js   | 361 +++++++++++-------
 packages/svelte/src/compiler/types/css.d.ts   |  10 +
 packages/svelte/tests/css-parse.test.ts       |  14 +-
 .../parser-legacy/samples/css/output.json     |   1 +
 .../whitespace-after-style-tag/output.json    |   1 +
 .../samples/css-nth-syntax/output.json        |  11 +-
 .../samples/css-pseudo-classes/output.json    | 173 ++++++++-
 .../script-style-no-markup/output.json        |  19 +
 .../semicolon-inside-quotes/output.json       |   4 +-
 .../print/samples/style-comments/input.svelte |  26 ++
 .../samples/style-comments/output.svelte      |  28 ++
 packages/svelte/types/index.d.ts              |  10 +
 19 files changed, 586 insertions(+), 175 deletions(-)
 create mode 100644 .changeset/soft-cats-comment.md
 create mode 100644 packages/svelte/tests/print/samples/style-comments/input.svelte
 create mode 100644 packages/svelte/tests/print/samples/style-comments/output.svelte

diff --git a/.changeset/soft-cats-comment.md b/.changeset/soft-cats-comment.md
new file mode 100644
index 0000000000..01b07c4d7d
--- /dev/null
+++ b/.changeset/soft-cats-comment.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: preserve CSS comments in the AST printer
diff --git a/packages/svelte/src/compiler/index.js b/packages/svelte/src/compiler/index.js
index 1d822514b9..599206ac6a 100644
--- a/packages/svelte/src/compiler/index.js
+++ b/packages/svelte/src/compiler/index.js
@@ -141,7 +141,8 @@ export function parseCss(source) {
 		type: 'StyleSheetFile',
 		start: 0,
 		end: source.length,
-		children
+		children,
+		comments: parser.css_comments
 	};
 }
 
diff --git a/packages/svelte/src/compiler/phases/1-parse/index.js b/packages/svelte/src/compiler/phases/1-parse/index.js
index 02d1629c99..fa7b292640 100644
--- a/packages/svelte/src/compiler/phases/1-parse/index.js
+++ b/packages/svelte/src/compiler/phases/1-parse/index.js
@@ -50,6 +50,9 @@ export class Parser {
 	/** */
 	index = 0;
 
+	/** @type {AST.CSS.CSSComment[]} */
+	css_comments = [];
+
 	/**
 	 * Creates a minimal parser instance for CSS-only parsing.
 	 * Skips Svelte component parsing setup.
@@ -61,6 +64,7 @@ export class Parser {
 		parser.template = source;
 		parser.index = 0;
 		parser.loose = false;
+		parser.css_comments = [];
 		return parser;
 	}
 
diff --git a/packages/svelte/src/compiler/phases/1-parse/read/style.js b/packages/svelte/src/compiler/phases/1-parse/read/style.js
index 160e5da277..5eb8c2b3e9 100644
--- a/packages/svelte/src/compiler/phases/1-parse/read/style.js
+++ b/packages/svelte/src/compiler/phases/1-parse/read/style.js
@@ -24,6 +24,7 @@ const REGEX_HTML_COMMENT_CLOSE = /-->/;
  */
 export default function read_style(parser, start, attributes) {
 	const content_start = parser.index;
+	parser.css_comments = [];
 	const children = read_body(parser, (p) => p.match('</style') || p.index >= p.template.length);
 	const content_end = parser.index;
 
@@ -36,6 +37,7 @@ export default function read_style(parser, start, attributes) {
 		end: parser.index,
 		attributes,
 		children,
+		comments: parser.css_comments,
 		content: {
 			start: content_start,
 			end: content_end,
@@ -229,18 +231,22 @@ function read_selector(parser, inside_pseudo_class = false) {
 				end: parser.index
 			});
 		} else if (parser.eat('::')) {
+			const name = read_identifier(parser);
+			/** @type {AST.CSS.SelectorList | null} */
+			let args = null;
+
+			if (parser.eat('(')) {
+				args = read_selector_list(parser, true);
+				parser.eat(')', true);
+			}
+
 			relative_selector.selectors.push({
 				type: 'PseudoElementSelector',
-				name: read_identifier(parser),
+				name,
 				start,
-				end: parser.index
+				end: parser.index,
+				...(args && { args })
 			});
-			// We read the inner selectors of a pseudo element to ensure it parses correctly,
-			// but we don't do anything with the result.
-			if (parser.eat('(')) {
-				read_selector_list(parser, true);
-				parser.eat(')', true);
-			}
 		} else if (parser.eat(':')) {
 			const name = read_identifier(parser);
 
@@ -323,7 +329,7 @@ function read_selector(parser, inside_pseudo_class = false) {
 		}
 
 		const index = parser.index;
-		allow_comment_or_whitespace(parser);
+		allow_comment_or_whitespace(parser, false);
 
 		if (parser.match(',') || (inside_pseudo_class ? parser.match(')') : parser.match('{'))) {
 			// rewind, so we know whether to continue building the selector list
@@ -449,7 +455,7 @@ function read_block_item(parser) {
 	// read ahead to understand whether we're dealing with a declaration or a nested rule.
 	// this involves some duplicated work, but avoids a try-catch that would disguise errors
 	const start = parser.index;
-	read_value(parser);
+	read_value(parser, false);
 	const char = parser.template[parser.index];
 	parser.index = start;
 
@@ -492,10 +498,13 @@ function read_declaration(parser) {
 
 /**
  * @param {Parser} parser
+ * @param {boolean} [capture_comments]
  * @returns {string}
  */
-function read_value(parser) {
+function read_value(parser, capture_comments = true) {
 	let value = '';
+	/** @type {AST.CSS.CSSComment[]} */
+	const value_comments = [];
 	let escaped = false;
 	let in_url = false;
 
@@ -523,6 +532,13 @@ function read_value(parser) {
 		} else if (char === '(' && value.slice(-3) === 'url') {
 			in_url = true;
 		} else if ((char === ';' || char === '{' || char === '}') && !in_url && !quote_mark) {
+			const leading_whitespace = value.length - value.trimStart().length;
+			for (const comment of value_comments) {
+				comment.position = Math.max(
+					0,
+					/** @type {number} */ (comment.position) - leading_whitespace
+				);
+			}
 			return value.trim();
 		} else if (
 			char === '/' &&
@@ -530,13 +546,11 @@ function read_value(parser) {
 			!quote_mark &&
 			parser.template[parser.index + 1] === '*'
 		) {
-			parser.index += 2;
-			while (parser.index < parser.template.length) {
-				if (parser.template[parser.index] === '*' && parser.template[parser.index + 1] === '/') {
-					parser.index += 2;
-					break;
-				}
-				parser.index++;
+			const comment = read_comment(parser);
+			if (capture_comments) {
+				comment.position = value.length;
+				parser.css_comments.push(comment);
+				value_comments.push(comment);
 			}
 			continue;
 		}
@@ -624,13 +638,16 @@ function read_identifier(parser) {
 	return identifier;
 }
 
-/** @param {Parser} parser */
-function allow_comment_or_whitespace(parser) {
+/**
+ * @param {Parser} parser
+ * @param {boolean} [capture_comments]
+ */
+function allow_comment_or_whitespace(parser, capture_comments = true) {
 	parser.allow_whitespace();
 	while (parser.match('/*') || parser.match('<!--')) {
-		if (parser.eat('/*')) {
-			parser.read_until(REGEX_COMMENT_CLOSE);
-			parser.eat('*/', true);
+		if (parser.match('/*')) {
+			const comment = read_comment(parser);
+			if (capture_comments) parser.css_comments.push(comment);
 		}
 
 		if (parser.eat('<!--')) {
@@ -642,6 +659,25 @@ function allow_comment_or_whitespace(parser) {
 	}
 }
 
+/**
+ * @param {Parser} parser
+ * @returns {AST.CSS.CSSComment}
+ */
+function read_comment(parser) {
+	const start = parser.index;
+	parser.eat('/*', true);
+	const value = parser.read_until(REGEX_COMMENT_CLOSE);
+	parser.eat('*/', true);
+	const end = parser.index;
+
+	return {
+		type: 'CSSComment',
+		value,
+		start,
+		end
+	};
+}
+
 /**
  * Parse standalone CSS content (not wrapped in `<style>`).
  * @param {Parser} parser
diff --git a/packages/svelte/src/compiler/phases/2-analyze/css/css-analyze.js b/packages/svelte/src/compiler/phases/2-analyze/css/css-analyze.js
index d6052c9c3e..023d4e768e 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/css/css-analyze.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/css/css-analyze.js
@@ -312,6 +312,9 @@ const css_visitors = {
 		}
 
 		context.next();
+	},
+	PseudoElementSelector() {
+		// Don't analyse these
 	}
 };
 
diff --git a/packages/svelte/src/compiler/phases/2-analyze/css/css-warn.js b/packages/svelte/src/compiler/phases/2-analyze/css/css-warn.js
index 238c83f00e..0964be1615 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/css/css-warn.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/css/css-warn.js
@@ -23,6 +23,9 @@ const visitors = {
 			context.next();
 		}
 	},
+	PseudoElementSelector() {
+		// Don't analyse these
+	},
 	ComplexSelector(node, context) {
 		if (
 			!node.metadata.used &&
diff --git a/packages/svelte/src/compiler/phases/3-transform/css/index.js b/packages/svelte/src/compiler/phases/3-transform/css/index.js
index 92b2706f22..537ab60a0e 100644
--- a/packages/svelte/src/compiler/phases/3-transform/css/index.js
+++ b/packages/svelte/src/compiler/phases/3-transform/css/index.js
@@ -374,6 +374,9 @@ const visitors = {
 		if (node.name === 'is' || node.name === 'where' || node.name === 'has' || node.name === 'not') {
 			context.next();
 		}
+	},
+	PseudoElementSelector() {
+		// Functional pseudo-element arguments are not scoped as selectors.
 	}
 };
 
diff --git a/packages/svelte/src/compiler/print/index.js b/packages/svelte/src/compiler/print/index.js
index fe76f31ad3..278cb0bd11 100644
--- a/packages/svelte/src/compiler/print/index.js
+++ b/packages/svelte/src/compiler/print/index.js
@@ -19,6 +19,9 @@ const LINE_BREAK_THRESHOLD = 50;
  */
 export function print(ast, options = undefined) {
 	const comments = (ast.type === 'Root' && ast.comments) || [];
+	const css_comments =
+		(ast.type === 'Root' ? ast.css?.comments : ast.type === 'StyleSheet' ? ast.comments : null) ||
+		[];
 
 	return esrap.print(
 		ast,
@@ -29,7 +32,7 @@ export function print(ast, options = undefined) {
 				getTrailingComments: options?.getTrailingComments
 			}),
 			...svelte_visitors(comments),
-			...css_visitors
+			...css_visitors(css_comments, comments)
 		}),
 		{
 			indent: options?.indent
@@ -177,161 +180,263 @@ function base_element(node, context, comments) {
 	context.append(child_context);
 }
 
-/** @type {Visitors<AST.SvelteNode>} */
-const css_visitors = {
-	Atrule(node, context) {
-		context.write(`@${node.name}`);
-		if (node.prelude) context.write(` ${node.prelude}`);
-
-		if (node.block) {
-			context.write(' ');
-			context.visit(node.block);
-		} else {
-			context.write(';');
-		}
-	},
+/**
+ * @param {AST.CSS.CSSComment[]} comments
+ * @param {AST.JSComment[]} js_comments
+ * @returns {Visitors<AST.SvelteNode>}
+ */
+function css_visitors(comments, js_comments) {
+	let comment_index = 0;
+
+	/** @param {number} end */
+	const has_comment_before = (end) => comments[comment_index]?.start < end;
+
+	/**
+	 * @param {Context} context
+	 * @param {AST.CSS.CSSComment} comment
+	 */
+	function write_comment(context, comment) {
+		context.write(`/*${comment.value}*/`);
+	}
 
-	AttributeSelector(node, context) {
-		context.write(`[${node.name}`);
-		if (node.matcher) {
-			context.write(node.matcher);
-			context.write(`"${node.value}"`);
-			if (node.flags) {
-				context.write(` ${node.flags}`);
-			}
+	/**
+	 * @param {Context} context
+	 * @param {number} end
+	 */
+	function write_inline_comments(context, end) {
+		let written = false;
+
+		while (has_comment_before(end)) {
+			if (written) context.write(' ');
+			write_comment(context, comments[comment_index++]);
+			written = true;
 		}
-		context.write(']');
-	},
 
-	Block(node, context) {
-		context.write('{');
+		return written;
+	}
 
-		if (node.children.length > 0) {
-			context.indent();
-			context.newline();
+	/**
+	 * @param {Context} context
+	 * @param {string} value
+	 * @param {number} end
+	 */
+	function write_value(context, value, end) {
+		let offset = 0;
+
+		while (has_comment_before(end)) {
+			const comment = comments[comment_index++];
+			const position = Math.max(offset, Math.min(comment.position ?? 0, value.length));
+			context.write(value.slice(offset, position));
+			write_comment(context, comment);
+			offset = position;
+		}
 
-			let started = false;
+		context.write(value.slice(offset));
+	}
 
-			for (const child of node.children) {
-				if (started) {
-					context.newline();
-				}
+	/**
+	 * @param {Context} context
+	 * @param {Array<AST.CSS.Rule | AST.CSS.Atrule | AST.CSS.Declaration>} children
+	 * @param {number} end
+	 * @param {boolean} margins
+	 */
+	function print_children(context, children, end, margins) {
+		let started = false;
 
-				context.visit(child);
+		const separate = () => {
+			if (!started) return;
+			if (margins) context.margin();
+			context.newline();
+		};
 
+		for (const child of children) {
+			while (has_comment_before(child.start)) {
+				separate();
+				write_comment(context, comments[comment_index++]);
 				started = true;
 			}
 
-			context.dedent();
-			context.newline();
+			separate();
+			context.visit(child);
+			started = true;
 		}
 
-		context.write('}');
-	},
+		while (has_comment_before(end)) {
+			separate();
+			write_comment(context, comments[comment_index++]);
+			started = true;
+		}
+	}
 
-	ClassSelector(node, context) {
-		context.write(`.${node.name}`);
-	},
+	/**
+	 * @param {AST.CSS.SelectorList} node
+	 * @param {Context} context
+	 * @param {boolean} multiline
+	 */
+	function print_selector_list(node, context, multiline) {
+		let needs_separator = false;
+		let remaining_selectors = node.children.length;
 
-	ComplexSelector(node, context) {
 		for (const selector of node.children) {
+			while (has_comment_before(selector.start)) {
+				if (needs_separator) context.write(' ');
+				write_comment(context, comments[comment_index++]);
+				needs_separator = true;
+			}
+
+			if (needs_separator) {
+				if (multiline) context.newline();
+				else context.write(' ');
+			}
+
 			context.visit(selector);
+			needs_separator = true;
+			remaining_selectors -= 1;
+
+			if (remaining_selectors > 0) context.write(',');
 		}
-	},
+	}
 
-	Declaration(node, context) {
-		context.write(`${node.property}: ${node.value};`);
-	},
+	return {
+		Atrule(node, context) {
+			context.write(`@${node.name}`);
 
-	IdSelector(node, context) {
-		context.write(`#${node.name}`);
-	},
+			const prelude_end = node.block?.start ?? node.end;
+			if (node.prelude || has_comment_before(prelude_end)) {
+				context.write(' ');
+				write_value(context, node.prelude, prelude_end);
+			}
 
-	NestingSelector(node, context) {
-		context.write('&');
-	},
+			if (node.block) {
+				context.write(' ');
+				context.visit(node.block);
+			} else {
+				context.write(';');
+			}
+		},
+
+		AttributeSelector(node, context) {
+			context.write(`[${node.name}`);
+			if (node.matcher) {
+				context.write(node.matcher);
+				context.write(`"${node.value}"`);
+				if (node.flags) context.write(` ${node.flags}`);
+			}
+			context.write(']');
+		},
 
-	Nth(node, context) {
-		context.write(node.value);
-	},
+		Block(node, context) {
+			context.write('{');
 
-	Percentage(node, context) {
-		context.write(node.value);
-	},
+			if (node.children.length > 0 || has_comment_before(node.end)) {
+				context.indent();
+				context.newline();
+				print_children(context, node.children, node.end, false);
+				context.dedent();
+				context.newline();
+			}
 
-	PseudoClassSelector(node, context) {
-		context.write(`:${node.name}`);
+			context.write('}');
+		},
 
-		if (node.args) {
-			context.write('(');
+		ClassSelector(node, context) {
+			context.write(`.${node.name}`);
+		},
 
-			let started = false;
+		ComplexSelector(node, context) {
+			for (const selector of node.children) context.visit(selector);
+		},
 
-			for (const arg of node.args.children) {
-				if (started) {
-					context.write(', ');
-				}
+		Declaration(node, context) {
+			context.write(`${node.property}: `);
+			write_value(context, node.value, node.end);
+			context.write(';');
+		},
 
-				context.visit(arg);
+		IdSelector(node, context) {
+			context.write(`#${node.name}`);
+		},
 
-				started = true;
-			}
+		NestingSelector(node, context) {
+			context.write('&');
+		},
 
-			context.write(')');
-		}
-	},
+		Nth(node, context) {
+			context.write(node.value);
+		},
 
-	PseudoElementSelector(node, context) {
-		context.write(`::${node.name}`);
-	},
+		Percentage(node, context) {
+			context.write(node.value);
+		},
 
-	RelativeSelector(node, context) {
-		if (node.combinator) {
-			if (node.combinator.name === ' ') {
-				context.write(' ');
-			} else {
-				context.write(` ${node.combinator.name} `);
+		PseudoClassSelector(node, context) {
+			context.write(`:${node.name}`);
+
+			if (node.args) {
+				context.write('(');
+				context.visit(node.args);
+				if (has_comment_before(node.end)) {
+					context.write(' ');
+					write_inline_comments(context, node.end);
+				}
+				context.write(')');
 			}
-		}
+		},
+
+		PseudoElementSelector(node, context) {
+			context.write(`::${node.name}`);
+			if (node.args) {
+				context.write('(');
+				context.visit(node.args);
+				if (has_comment_before(node.end)) {
+					context.write(' ');
+					write_inline_comments(context, node.end);
+				}
+				context.write(')');
+			}
+		},
 
-		for (const selector of node.selectors) {
-			context.visit(selector);
-		}
-	},
+		RelativeSelector(node, context) {
+			if (node.combinator) {
+				if (node.combinator.name === ' ') context.write(' ');
+				else context.write(` ${node.combinator.name} `);
+			}
 
-	Rule(node, context) {
-		let started = false;
+			for (const selector of node.selectors) context.visit(selector);
+		},
 
-		for (const selector of node.prelude.children) {
-			if (started) {
-				context.write(',');
-				context.newline();
-			}
+		Rule(node, context) {
+			print_selector_list(node.prelude, context, true);
+			context.write(' ');
+			if (write_inline_comments(context, node.block.start)) context.write(' ');
+			context.visit(node.block);
+		},
 
-			context.visit(selector);
-			started = true;
-		}
+		SelectorList(node, context) {
+			print_selector_list(node, context, false);
+		},
 
-		context.write(' ');
-		context.visit(node.block);
-	},
+		StyleSheet(node, context) {
+			context.write('<style');
+			attributes(node, node.attributes, context, js_comments);
+			context.write('>');
 
-	SelectorList(node, context) {
-		let started = false;
-		for (const selector of node.children) {
-			if (started) {
-				context.write(', ');
+			if (node.children.length > 0 || node.comments.length > 0) {
+				context.indent();
+				context.newline();
+				print_children(context, node.children, node.content.end, true);
+				context.dedent();
+				context.newline();
 			}
 
-			context.visit(selector);
-			started = true;
-		}
-	},
+			context.write('</style>');
+		},
 
-	TypeSelector(node, context) {
-		context.write(node.name);
-	}
-};
+		TypeSelector(node, context) {
+			context.write(node.name);
+		}
+	};
+}
 
 /**
  * @param {AST.JSComment[]} comments
@@ -845,34 +950,6 @@ const svelte_visitors = (comments) => ({
 		}
 	},
 
-	StyleSheet(node, context) {
-		context.write('<style');
-		attributes(node, node.attributes, context, comments);
-		context.write('>');
-
-		if (node.children.length > 0) {
-			context.indent();
-			context.newline();
-
-			let started = false;
-
-			for (const child of node.children) {
-				if (started) {
-					context.margin();
-					context.newline();
-				}
-
-				context.visit(child);
-				started = true;
-			}
-
-			context.dedent();
-			context.newline();
-		}
-
-		context.write('</style>');
-	},
-
 	SvelteBody(node, context) {
 		base_element(node, context, comments);
 	},
diff --git a/packages/svelte/src/compiler/types/css.d.ts b/packages/svelte/src/compiler/types/css.d.ts
index 13eb880d83..b0a763b6a1 100644
--- a/packages/svelte/src/compiler/types/css.d.ts
+++ b/packages/svelte/src/compiler/types/css.d.ts
@@ -8,6 +8,15 @@ export namespace _CSS {
 
 	export interface StyleSheetBase extends BaseNode {
 		children: Array<Atrule | Rule>;
+		/** CSS comments in source order */
+		comments: CSSComment[];
+	}
+
+	export interface CSSComment extends BaseNode {
+		type: 'CSSComment';
+		value: string;
+		/** Character offset in a containing declaration value or at-rule prelude */
+		position?: number;
 	}
 
 	export interface StyleSheetFile extends StyleSheetBase {
@@ -135,6 +144,7 @@ export namespace _CSS {
 	export interface PseudoElementSelector extends BaseNode {
 		type: 'PseudoElementSelector';
 		name: string;
+		args?: SelectorList;
 	}
 
 	export interface PseudoClassSelector extends BaseNode {
diff --git a/packages/svelte/tests/css-parse.test.ts b/packages/svelte/tests/css-parse.test.ts
index 3a53e97955..18903f0619 100644
--- a/packages/svelte/tests/css-parse.test.ts
+++ b/packages/svelte/tests/css-parse.test.ts
@@ -69,9 +69,21 @@ describe('parseCss', () => {
 	});
 
 	it('parses comments', () => {
-		const ast = parseCss('/* comment */ div { color: red; }');
+		const ast = parseCss(
+			'/* top */ div, /* selector */ span { /* block */ color: /* value */ red; }'
+		);
 		assert.equal(ast.children.length, 1);
 		assert.equal(ast.children[0].type, 'Rule');
+		assert.deepEqual(
+			ast.comments.map((comment) => comment.value),
+			[' top ', ' selector ', ' block ', ' value ']
+		);
+		assert.deepEqual(ast.comments[0], {
+			type: 'CSSComment',
+			value: ' top ',
+			start: 0,
+			end: 9
+		});
 	});
 
 	it('parses complex selectors', () => {
diff --git a/packages/svelte/tests/parser-legacy/samples/css/output.json b/packages/svelte/tests/parser-legacy/samples/css/output.json
index b3ecd7b671..82be06eeac 100644
--- a/packages/svelte/tests/parser-legacy/samples/css/output.json
+++ b/packages/svelte/tests/parser-legacy/samples/css/output.json
@@ -33,6 +33,7 @@
 		"type": "Style",
 		"start": 16,
 		"end": 56,
+		"comments": [],
 		"attributes": [],
 		"children": [
 			{
diff --git a/packages/svelte/tests/parser-legacy/samples/whitespace-after-style-tag/output.json b/packages/svelte/tests/parser-legacy/samples/whitespace-after-style-tag/output.json
index 2cadbc672f..3d17122d1f 100644
--- a/packages/svelte/tests/parser-legacy/samples/whitespace-after-style-tag/output.json
+++ b/packages/svelte/tests/parser-legacy/samples/whitespace-after-style-tag/output.json
@@ -33,6 +33,7 @@
 		"type": "Style",
 		"start": 16,
 		"end": 66,
+		"comments": [],
 		"attributes": [],
 		"children": [
 			{
diff --git a/packages/svelte/tests/parser-modern/samples/css-nth-syntax/output.json b/packages/svelte/tests/parser-modern/samples/css-nth-syntax/output.json
index 3ce5f33d09..e0adab2b9f 100644
--- a/packages/svelte/tests/parser-modern/samples/css-nth-syntax/output.json
+++ b/packages/svelte/tests/parser-modern/samples/css-nth-syntax/output.json
@@ -1071,6 +1071,14 @@
 				"end": 797
 			}
 		],
+		"comments": [
+			{
+				"type": "CSSComment",
+				"value": " test that all these are parsed correctly ",
+				"start": 12,
+				"end": 58
+			}
+		],
 		"content": {
 			"start": 7,
 			"end": 798,
@@ -1125,5 +1133,6 @@
 			}
 		]
 	},
-	"options": null
+	"options": null,
+	"comments": []
 }
diff --git a/packages/svelte/tests/parser-modern/samples/css-pseudo-classes/output.json b/packages/svelte/tests/parser-modern/samples/css-pseudo-classes/output.json
index d052affe46..714bb9ee19 100644
--- a/packages/svelte/tests/parser-modern/samples/css-pseudo-classes/output.json
+++ b/packages/svelte/tests/parser-modern/samples/css-pseudo-classes/output.json
@@ -25,7 +25,35 @@
 											"type": "PseudoElementSelector",
 											"name": "view-transition-old",
 											"start": 60,
-											"end": 81
+											"end": 86,
+											"args": {
+												"type": "SelectorList",
+												"start": 82,
+												"end": 85,
+												"children": [
+													{
+														"type": "ComplexSelector",
+														"start": 82,
+														"end": 85,
+														"children": [
+															{
+																"type": "RelativeSelector",
+																"combinator": null,
+																"selectors": [
+																	{
+																		"type": "TypeSelector",
+																		"name": "x-y",
+																		"start": 82,
+																		"end": 85
+																	}
+																],
+																"start": 82,
+																"end": 85
+															}
+														]
+													}
+												]
+											}
 										}
 									],
 									"start": 60,
@@ -89,7 +117,35 @@
 																		"type": "PseudoElementSelector",
 																		"name": "view-transition-old",
 																		"start": 119,
-																		"end": 140
+																		"end": 145,
+																		"args": {
+																			"type": "SelectorList",
+																			"start": 141,
+																			"end": 144,
+																			"children": [
+																				{
+																					"type": "ComplexSelector",
+																					"start": 141,
+																					"end": 144,
+																					"children": [
+																						{
+																							"type": "RelativeSelector",
+																							"combinator": null,
+																							"selectors": [
+																								{
+																									"type": "TypeSelector",
+																									"name": "x-y",
+																									"start": 141,
+																									"end": 144
+																								}
+																							],
+																							"start": 141,
+																							"end": 144
+																						}
+																					]
+																				}
+																			]
+																		}
 																	}
 																],
 																"start": 119,
@@ -147,7 +203,35 @@
 											"type": "PseudoElementSelector",
 											"name": "highlight",
 											"start": 171,
-											"end": 182
+											"end": 199,
+											"args": {
+												"type": "SelectorList",
+												"start": 183,
+												"end": 198,
+												"children": [
+													{
+														"type": "ComplexSelector",
+														"start": 183,
+														"end": 198,
+														"children": [
+															{
+																"type": "RelativeSelector",
+																"combinator": null,
+																"selectors": [
+																	{
+																		"type": "TypeSelector",
+																		"name": "rainbow-color-1",
+																		"start": 183,
+																		"end": 198
+																	}
+																],
+																"start": 183,
+																"end": 198
+															}
+														]
+													}
+												]
+											}
 										}
 									],
 									"start": 171,
@@ -200,7 +284,35 @@
 											"type": "PseudoElementSelector",
 											"name": "part",
 											"start": 234,
-											"end": 240
+											"end": 245,
+											"args": {
+												"type": "SelectorList",
+												"start": 241,
+												"end": 244,
+												"children": [
+													{
+														"type": "ComplexSelector",
+														"start": 241,
+														"end": 244,
+														"children": [
+															{
+																"type": "RelativeSelector",
+																"combinator": null,
+																"selectors": [
+																	{
+																		"type": "TypeSelector",
+																		"name": "foo",
+																		"start": 241,
+																		"end": 244
+																	}
+																],
+																"start": 241,
+																"end": 244
+															}
+														]
+													}
+												]
+											}
 										}
 									],
 									"start": 220,
@@ -247,7 +359,35 @@
 											"type": "PseudoElementSelector",
 											"name": "slotted",
 											"start": 266,
-											"end": 275
+											"end": 285,
+											"args": {
+												"type": "SelectorList",
+												"start": 276,
+												"end": 284,
+												"children": [
+													{
+														"type": "ComplexSelector",
+														"start": 276,
+														"end": 284,
+														"children": [
+															{
+																"type": "RelativeSelector",
+																"combinator": null,
+																"selectors": [
+																	{
+																		"type": "ClassSelector",
+																		"name": "content",
+																		"start": 276,
+																		"end": 284
+																	}
+																],
+																"start": 276,
+																"end": 284
+															}
+														]
+													}
+												]
+											}
 										}
 									],
 									"start": 266,
@@ -390,6 +530,26 @@
 				"end": 377
 			}
 		],
+		"comments": [
+			{
+				"type": "CSSComment",
+				"value": " test that all these are parsed correctly ",
+				"start": 12,
+				"end": 58
+			},
+			{
+				"type": "CSSComment",
+				"value": "button",
+				"start": 311,
+				"end": 321
+			},
+			{
+				"type": "CSSComment",
+				"value": "p after h1",
+				"start": 332,
+				"end": 346
+			}
+		],
 		"content": {
 			"start": 7,
 			"end": 378,
@@ -405,5 +565,6 @@
 		"type": "Fragment",
 		"nodes": []
 	},
-	"options": null
+	"options": null,
+	"comments": []
 }
diff --git a/packages/svelte/tests/parser-modern/samples/script-style-no-markup/output.json b/packages/svelte/tests/parser-modern/samples/script-style-no-markup/output.json
index db58a62148..68c38da524 100644
--- a/packages/svelte/tests/parser-modern/samples/script-style-no-markup/output.json
+++ b/packages/svelte/tests/parser-modern/samples/script-style-no-markup/output.json
@@ -53,6 +53,7 @@
 				"end": 82
 			}
 		],
+		"comments": [],
 		"content": {
 			"start": 61,
 			"end": 83,
@@ -77,6 +78,24 @@
 		]
 	},
 	"options": null,
+	"comments": [
+		{
+			"type": "Line",
+			"value": " script and style but no markup",
+			"start": 10,
+			"end": 43,
+			"loc": {
+				"start": {
+					"line": 2,
+					"column": 1
+				},
+				"end": {
+					"line": 2,
+					"column": 34
+				}
+			}
+		}
+	],
 	"instance": {
 		"type": "Script",
 		"start": 0,
diff --git a/packages/svelte/tests/parser-modern/samples/semicolon-inside-quotes/output.json b/packages/svelte/tests/parser-modern/samples/semicolon-inside-quotes/output.json
index 312bd7701e..66a63580b1 100644
--- a/packages/svelte/tests/parser-modern/samples/semicolon-inside-quotes/output.json
+++ b/packages/svelte/tests/parser-modern/samples/semicolon-inside-quotes/output.json
@@ -68,6 +68,7 @@
 				"end": 196
 			}
 		],
+		"comments": [],
 		"content": {
 			"start": 43,
 			"end": 197,
@@ -122,5 +123,6 @@
 			}
 		]
 	},
-	"options": null
+	"options": null,
+	"comments": []
 }
diff --git a/packages/svelte/tests/print/samples/style-comments/input.svelte b/packages/svelte/tests/print/samples/style-comments/input.svelte
new file mode 100644
index 0000000000..71b2505891
--- /dev/null
+++ b/packages/svelte/tests/print/samples/style-comments/input.svelte
@@ -0,0 +1,26 @@
+<style>
+	/* first */
+	/* second */
+	.foo, /* between */
+	.bar /* trailing */ {
+		/* block */
+		color: r /* value */ ed;
+	}
+
+	@media screen/* media */and (width > 0) {
+		/* nested */
+		.baz {
+			display: block;
+		}
+	}
+
+	.empty {
+		/* only */
+	}
+
+	.part::part(/* argument */ label) {
+		display: block;
+	}
+
+	/* last */
+</style>
diff --git a/packages/svelte/tests/print/samples/style-comments/output.svelte b/packages/svelte/tests/print/samples/style-comments/output.svelte
new file mode 100644
index 0000000000..cb913cc0b5
--- /dev/null
+++ b/packages/svelte/tests/print/samples/style-comments/output.svelte
@@ -0,0 +1,28 @@
+<style>
+	/* first */
+
+	/* second */
+
+	.foo, /* between */
+	.bar /* trailing */ {
+		/* block */
+		color: r /* value */ ed;
+	}
+
+	@media screen/* media */and (width > 0) {
+		/* nested */
+		.baz {
+			display: block;
+		}
+	}
+
+	.empty {
+		/* only */
+	}
+
+	.part::part(/* argument */ label) {
+		display: block;
+	}
+
+	/* last */
+</style>
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index d758022ae4..b89f61959f 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -1694,6 +1694,15 @@ declare module 'svelte/compiler' {
 
 		export interface StyleSheetBase extends BaseNode {
 			children: Array<Atrule | Rule>;
+			/** CSS comments in source order */
+			comments: CSSComment[];
+		}
+
+		export interface CSSComment extends BaseNode {
+			type: 'CSSComment';
+			value: string;
+			/** Character offset in a containing declaration value or at-rule prelude */
+			position?: number;
 		}
 
 		export interface StyleSheetFile extends StyleSheetBase {
@@ -1788,6 +1797,7 @@ declare module 'svelte/compiler' {
 		export interface PseudoElementSelector extends BaseNode {
 			type: 'PseudoElementSelector';
 			name: string;
+			args?: SelectorList;
 		}
 
 		export interface PseudoClassSelector extends BaseNode {

From ee6dff80cae6fdcb068647322090765c77f67ee4 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Wed, 12 Aug 2026 19:34:47 +0200
Subject: [PATCH 121/222] fix: better whitespace handling inside printer
 (#18638)

- preserve whitespace around elements if it leads to a line break
- preserve whitespace for whitespace-sensitive elements (pre, textarea,
title)

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/metal-cougars-chew.md              |   5 +
 packages/svelte/src/compiler/print/index.js   | 104 +++++++++++++-----
 .../element-content-wrapping/input.svelte     |   5 +
 .../element-content-wrapping/output.svelte    |   5 +
 .../preserve-whitespace-elements/input.svelte |  19 ++++
 .../output.svelte                             |  21 ++++
 6 files changed, 130 insertions(+), 29 deletions(-)
 create mode 100644 .changeset/metal-cougars-chew.md
 create mode 100644 packages/svelte/tests/print/samples/element-content-wrapping/input.svelte
 create mode 100644 packages/svelte/tests/print/samples/element-content-wrapping/output.svelte
 create mode 100644 packages/svelte/tests/print/samples/preserve-whitespace-elements/input.svelte
 create mode 100644 packages/svelte/tests/print/samples/preserve-whitespace-elements/output.svelte

diff --git a/.changeset/metal-cougars-chew.md b/.changeset/metal-cougars-chew.md
new file mode 100644
index 0000000000..a75fc14a55
--- /dev/null
+++ b/.changeset/metal-cougars-chew.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: better whitespace handling inside printer
diff --git a/packages/svelte/src/compiler/print/index.js b/packages/svelte/src/compiler/print/index.js
index 278cb0bd11..8759fe3013 100644
--- a/packages/svelte/src/compiler/print/index.js
+++ b/packages/svelte/src/compiler/print/index.js
@@ -19,6 +19,7 @@ const LINE_BREAK_THRESHOLD = 50;
  */
 export function print(ast, options = undefined) {
 	const comments = (ast.type === 'Root' && ast.comments) || [];
+	const state = { preserve_whitespace: 0 };
 	const css_comments =
 		(ast.type === 'Root' ? ast.css?.comments : ast.type === 'StyleSheet' ? ast.comments : null) ||
 		[];
@@ -31,7 +32,7 @@ export function print(ast, options = undefined) {
 				getLeadingComments: options?.getLeadingComments,
 				getTrailingComments: options?.getTrailingComments
 			}),
-			...svelte_visitors(comments),
+			...svelte_visitors(comments, state),
 			...css_visitors(css_comments, comments)
 		}),
 		{
@@ -43,9 +44,15 @@ export function print(ast, options = undefined) {
 /**
  * @param {Context} context
  * @param {AST.SvelteNode} node
+ * @param {boolean} preserve_whitespace
  * @param {boolean} allow_inline
  */
-function block(context, node, allow_inline = false) {
+function block(context, node, preserve_whitespace = false, allow_inline = false) {
+	if (preserve_whitespace) {
+		context.visit(node);
+		return;
+	}
+
 	const child_context = context.new();
 	child_context.visit(node);
 
@@ -146,8 +153,9 @@ function attributes(node, attributes, context, comments) {
  * @param {AST.BaseElement} node
  * @param {Context} context
  * @param {AST.JSComment[]} comments
+ * @param {{ preserve_whitespace: number }} state
  */
-function base_element(node, context, comments) {
+function base_element(node, context, comments, state) {
 	const child_context = context.new();
 
 	child_context.write('<' + node.name);
@@ -173,13 +181,30 @@ function base_element(node, context, comments) {
 		child_context.write(`${multiline_attributes ? '' : ' '}/>`);
 	} else {
 		child_context.write('>');
-		block(child_context, node.fragment, true);
+		block(child_context, node.fragment, state.preserve_whitespace > 0, true);
 		child_context.write(`</${node.name}>`);
 	}
 
 	context.append(child_context);
 }
 
+/**
+ * @param {AST.BaseElement} node
+ * @param {Context} context
+ * @param {AST.JSComment[]} comments
+ * @param {{ preserve_whitespace: number }} state
+ */
+function print_element(node, context, comments, state) {
+	const name = node.name.toLowerCase();
+	const preserve =
+		(node.type === 'RegularElement' || node.type === 'TitleElement') &&
+		(name === 'pre' || name === 'textarea' || name === 'title');
+
+	if (preserve) state.preserve_whitespace += 1;
+	base_element(node, context, comments, state);
+	if (preserve) state.preserve_whitespace -= 1;
+}
+
 /**
  * @param {AST.CSS.CSSComment[]} comments
  * @param {AST.JSComment[]} js_comments
@@ -440,9 +465,10 @@ function css_visitors(comments, js_comments) {
 
 /**
  * @param {AST.JSComment[]} comments
+ * @param {{ preserve_whitespace: number }} state
  * @returns {Visitors<AST.SvelteNode>}
  */
-const svelte_visitors = (comments) => ({
+const svelte_visitors = (comments, state) => ({
 	Root(node, context) {
 		if (node.options) {
 			context.write('<svelte:options');
@@ -474,11 +500,27 @@ const svelte_visitors = (comments) => ({
 		context.write('<script');
 		attributes(node, node.attributes, context, comments);
 		context.write('>');
-		block(context, node.content);
+		block(context, node.content, state.preserve_whitespace > 0);
 		context.write('</script>');
 	},
 
 	Fragment(node, context) {
+		if (state.preserve_whitespace > 0) {
+			for (const child of node.nodes) {
+				context.visit(child);
+				context.multiline ||= child.type === 'Text' && /[\r\n]/.test(child.data);
+			}
+			return;
+		}
+
+		const first = node.nodes[0];
+		const last = node.nodes.at(-1);
+		const has_surrounding_whitespace =
+			first?.type === 'Text' &&
+			/^\s/.test(first.data) &&
+			last?.type === 'Text' &&
+			/\s$/.test(last.data);
+
 		/** @type {AST.SvelteNode[][]} */
 		const items = [];
 
@@ -570,6 +612,10 @@ const svelte_visitors = (comments) => ({
 			});
 
 		multiline ||= width > LINE_BREAK_THRESHOLD;
+		// Normally context.newline() also makes context.multiline true, but the below loop only
+		// does that if we have more than one child context. If there's one long text block inside
+		// with whitespace at the edges we wanna split that up, too.
+		context.multiline ||= has_surrounding_whitespace && width > LINE_BREAK_THRESHOLD * 2;
 
 		for (let i = 0; i < child_contexts.length; i += 1) {
 			const prev = child_contexts[i];
@@ -636,7 +682,7 @@ const svelte_visitors = (comments) => ({
 
 		if (node.pending) {
 			context.write('}');
-			block(context, node.pending);
+			block(context, node.pending, state.preserve_whitespace > 0);
 			context.write('{:');
 		} else {
 			context.write(' ');
@@ -647,7 +693,7 @@ const svelte_visitors = (comments) => ({
 			if (node.value) context.visit(node.value);
 			context.write('}');
 
-			block(context, node.then);
+			block(context, node.then, state.preserve_whitespace > 0);
 
 			if (node.catch) {
 				context.write('{:');
@@ -659,7 +705,7 @@ const svelte_visitors = (comments) => ({
 			if (node.error) context.visit(node.error);
 			context.write('}');
 
-			block(context, node.catch);
+			block(context, node.catch, state.preserve_whitespace > 0);
 		}
 
 		context.write('{/await}');
@@ -703,7 +749,7 @@ const svelte_visitors = (comments) => ({
 	},
 
 	Component(node, context) {
-		base_element(node, context, comments);
+		print_element(node, context, comments, state);
 	},
 
 	ConstTag(node, context) {
@@ -793,11 +839,11 @@ const svelte_visitors = (comments) => ({
 
 		context.write('}');
 
-		block(context, node.body);
+		block(context, node.body, state.preserve_whitespace > 0);
 
 		if (node.fallback) {
 			context.write('{:else}');
-			block(context, node.fallback);
+			block(context, node.fallback, state.preserve_whitespace > 0);
 		}
 
 		context.write('{/each}');
@@ -821,13 +867,13 @@ const svelte_visitors = (comments) => ({
 			context.visit(node.test);
 			context.write('}');
 
-			block(context, node.consequent);
+			block(context, node.consequent, state.preserve_whitespace > 0);
 		} else {
 			context.write('{#if ');
 			context.visit(node.test);
 			context.write('}');
 
-			block(context, node.consequent);
+			block(context, node.consequent, state.preserve_whitespace > 0);
 		}
 
 		if (node.alternate !== null) {
@@ -839,7 +885,7 @@ const svelte_visitors = (comments) => ({
 				)
 			) {
 				context.write('{:else}');
-				block(context, node.alternate);
+				block(context, node.alternate, state.preserve_whitespace > 0);
 			} else {
 				context.visit(node.alternate);
 			}
@@ -854,7 +900,7 @@ const svelte_visitors = (comments) => ({
 		context.write('{#key ');
 		context.visit(node.expression);
 		context.write('}');
-		block(context, node.fragment);
+		block(context, node.fragment, state.preserve_whitespace > 0);
 		context.write('{/key}');
 	},
 
@@ -886,7 +932,7 @@ const svelte_visitors = (comments) => ({
 	},
 
 	RegularElement(node, context) {
-		base_element(node, context, comments);
+		print_element(node, context, comments, state);
 	},
 
 	RenderTag(node, context) {
@@ -896,7 +942,7 @@ const svelte_visitors = (comments) => ({
 	},
 
 	SlotElement(node, context) {
-		base_element(node, context, comments);
+		print_element(node, context, comments, state);
 	},
 
 	SnippetBlock(node, context) {
@@ -915,7 +961,7 @@ const svelte_visitors = (comments) => ({
 		}
 
 		context.write(')}');
-		block(context, node.body);
+		block(context, node.body, state.preserve_whitespace > 0);
 		context.write('{/snippet}');
 	},
 
@@ -951,11 +997,11 @@ const svelte_visitors = (comments) => ({
 	},
 
 	SvelteBody(node, context) {
-		base_element(node, context, comments);
+		print_element(node, context, comments, state);
 	},
 
 	SvelteBoundary(node, context) {
-		base_element(node, context, comments);
+		print_element(node, context, comments, state);
 	},
 
 	SvelteComponent(node, context) {
@@ -967,7 +1013,7 @@ const svelte_visitors = (comments) => ({
 		attributes(node, node.attributes, context, comments);
 		if (node.fragment && node.fragment.nodes.length > 0) {
 			context.write('>');
-			block(context, node.fragment, true);
+			block(context, node.fragment, state.preserve_whitespace > 0, true);
 			context.write(`</svelte:component>`);
 		} else {
 			context.write(' />');
@@ -975,7 +1021,7 @@ const svelte_visitors = (comments) => ({
 	},
 
 	SvelteDocument(node, context) {
-		base_element(node, context, comments);
+		print_element(node, context, comments, state);
 	},
 
 	SvelteElement(node, context) {
@@ -988,7 +1034,7 @@ const svelte_visitors = (comments) => ({
 
 		if (node.fragment && node.fragment.nodes.length > 0) {
 			context.write('>');
-			block(context, node.fragment);
+			block(context, node.fragment, state.preserve_whitespace > 0);
 			context.write(`</svelte:element>`);
 		} else {
 			context.write(' />');
@@ -996,19 +1042,19 @@ const svelte_visitors = (comments) => ({
 	},
 
 	SvelteFragment(node, context) {
-		base_element(node, context, comments);
+		print_element(node, context, comments, state);
 	},
 
 	SvelteHead(node, context) {
-		base_element(node, context, comments);
+		print_element(node, context, comments, state);
 	},
 
 	SvelteSelf(node, context) {
-		base_element(node, context, comments);
+		print_element(node, context, comments, state);
 	},
 
 	SvelteWindow(node, context) {
-		base_element(node, context, comments);
+		print_element(node, context, comments, state);
 	},
 
 	Text(node, context) {
@@ -1016,7 +1062,7 @@ const svelte_visitors = (comments) => ({
 	},
 
 	TitleElement(node, context) {
-		base_element(node, context, comments);
+		print_element(node, context, comments, state);
 	},
 
 	TransitionDirective(node, context) {
diff --git a/packages/svelte/tests/print/samples/element-content-wrapping/input.svelte b/packages/svelte/tests/print/samples/element-content-wrapping/input.svelte
new file mode 100644
index 0000000000..0667ace4fd
--- /dev/null
+++ b/packages/svelte/tests/print/samples/element-content-wrapping/input.svelte
@@ -0,0 +1,5 @@
+<button asdasd asdioqwjdoiqwjd qowdjqwoidjqowijdoiqj>
+    hello very long liiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiine
+</button>
+
+<span>hello very long liiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiine</span>
diff --git a/packages/svelte/tests/print/samples/element-content-wrapping/output.svelte b/packages/svelte/tests/print/samples/element-content-wrapping/output.svelte
new file mode 100644
index 0000000000..15622e960e
--- /dev/null
+++ b/packages/svelte/tests/print/samples/element-content-wrapping/output.svelte
@@ -0,0 +1,5 @@
+<button asdasd asdioqwjdoiqwjd qowdjqwoidjqowijdoiqj>
+	hello very long liiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiine
+</button>
+
+<span>hello very long liiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiine</span>
diff --git a/packages/svelte/tests/print/samples/preserve-whitespace-elements/input.svelte b/packages/svelte/tests/print/samples/preserve-whitespace-elements/input.svelte
new file mode 100644
index 0000000000..0736fd6bf5
--- /dev/null
+++ b/packages/svelte/tests/print/samples/preserve-whitespace-elements/input.svelte
@@ -0,0 +1,19 @@
+<pre>
+
+    hel
+
+    lo
+      .
+</pre>
+
+<pre>  before
+<span>  nested
+ text  </span>
+{#if visible}  conditional
+ value{/if}</pre>
+
+<textarea>  first
+    second  </textarea>
+
+<svelte:head><title>  hello
+  world  </title></svelte:head>
diff --git a/packages/svelte/tests/print/samples/preserve-whitespace-elements/output.svelte b/packages/svelte/tests/print/samples/preserve-whitespace-elements/output.svelte
new file mode 100644
index 0000000000..345a099dfc
--- /dev/null
+++ b/packages/svelte/tests/print/samples/preserve-whitespace-elements/output.svelte
@@ -0,0 +1,21 @@
+<pre>
+
+    hel
+
+    lo
+      .
+</pre>
+
+<pre>  before
+<span>  nested
+ text  </span>
+{#if visible}  conditional
+ value{/if}</pre>
+
+<textarea>  first
+    second  </textarea>
+
+<svelte:head>
+	<title>  hello
+  world  </title>
+</svelte:head>

From 20b341f10048cf1016a2028ac7eee5595cfef6a5 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Wed, 12 Aug 2026 14:08:05 -0400
Subject: [PATCH 122/222] Version Packages (#18628)

This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.


# Releases
## svelte@5.56.9

### Patch Changes

- fix: skip controlled each fast path while another batch is pending
([#18625](https://github.com/sveltejs/svelte/pull/18625))

- fix: better whitespace handling inside printer
([#18638](https://github.com/sveltejs/svelte/pull/18638))

- fix: don't duplicate comments in attributes
([#18636](https://github.com/sveltejs/svelte/pull/18636))

- fix: preserve CSS comments in the AST printer
([#18637](https://github.com/sveltejs/svelte/pull/18637))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/async-each-controlled-pending.md |  5 -----
 .changeset/metal-cougars-chew.md            |  5 -----
 .changeset/modern-otters-pick.md            |  5 -----
 .changeset/soft-cats-comment.md             |  5 -----
 packages/svelte/CHANGELOG.md                | 12 ++++++++++++
 packages/svelte/package.json                |  2 +-
 packages/svelte/src/version.js              |  2 +-
 7 files changed, 14 insertions(+), 22 deletions(-)
 delete mode 100644 .changeset/async-each-controlled-pending.md
 delete mode 100644 .changeset/metal-cougars-chew.md
 delete mode 100644 .changeset/modern-otters-pick.md
 delete mode 100644 .changeset/soft-cats-comment.md

diff --git a/.changeset/async-each-controlled-pending.md b/.changeset/async-each-controlled-pending.md
deleted file mode 100644
index c37f914d13..0000000000
--- a/.changeset/async-each-controlled-pending.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: skip controlled each fast path while another batch is pending
diff --git a/.changeset/metal-cougars-chew.md b/.changeset/metal-cougars-chew.md
deleted file mode 100644
index a75fc14a55..0000000000
--- a/.changeset/metal-cougars-chew.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: better whitespace handling inside printer
diff --git a/.changeset/modern-otters-pick.md b/.changeset/modern-otters-pick.md
deleted file mode 100644
index de5803e19f..0000000000
--- a/.changeset/modern-otters-pick.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: don't duplicate comments in attributes
diff --git a/.changeset/soft-cats-comment.md b/.changeset/soft-cats-comment.md
deleted file mode 100644
index 01b07c4d7d..0000000000
--- a/.changeset/soft-cats-comment.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: preserve CSS comments in the AST printer
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 722fc21052..5ec2101bf7 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,17 @@
 # svelte
 
+## 5.56.9
+
+### Patch Changes
+
+- fix: skip controlled each fast path while another batch is pending ([#18625](https://github.com/sveltejs/svelte/pull/18625))
+
+- fix: better whitespace handling inside printer ([#18638](https://github.com/sveltejs/svelte/pull/18638))
+
+- fix: don't duplicate comments in attributes ([#18636](https://github.com/sveltejs/svelte/pull/18636))
+
+- fix: preserve CSS comments in the AST printer ([#18637](https://github.com/sveltejs/svelte/pull/18637))
+
 ## 5.56.8
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 82dd4faf61..0bd1580969 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.56.8",
+  "version": "5.56.9",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 8fb86f3398..e3b4c740f0 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.56.8';
+export const VERSION = '5.56.9';
 export const PUBLIC_VERSION = '5';

From 135f4439c300b4bb996782e90f9d610b3373d574 Mon Sep 17 00:00:00 2001
From: Yuichiro Yamashita <xydybaseball@gmail.com>
Date: Fri, 14 Aug 2026 14:49:51 +0900
Subject: [PATCH 123/222] fix: increment private state fields through a
 non-`this` receiver (#18622)

---
 .changeset/quiet-donkeys-clap.md              |  5 ++++
 .../client/visitors/UpdateExpression.js       |  1 -
 .../_config.js                                | 22 ++++++++++++++++++
 .../main.svelte                               | 23 +++++++++++++++++++
 4 files changed, 50 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/quiet-donkeys-clap.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/class-private-state-increment-other-receiver/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/class-private-state-increment-other-receiver/main.svelte

diff --git a/.changeset/quiet-donkeys-clap.md b/.changeset/quiet-donkeys-clap.md
new file mode 100644
index 0000000000..dc9df3b7e1
--- /dev/null
+++ b/.changeset/quiet-donkeys-clap.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: increment private state fields through a non-`this` receiver
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/UpdateExpression.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/UpdateExpression.js
index 66952eb298..bc483daaed 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/UpdateExpression.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/UpdateExpression.js
@@ -13,7 +13,6 @@ export function UpdateExpression(node, context) {
 
 	if (
 		argument.type === 'MemberExpression' &&
-		argument.object.type === 'ThisExpression' &&
 		argument.property.type === 'PrivateIdentifier' &&
 		context.state.state_fields.has('#' + argument.property.name)
 	) {
diff --git a/packages/svelte/tests/runtime-runes/samples/class-private-state-increment-other-receiver/_config.js b/packages/svelte/tests/runtime-runes/samples/class-private-state-increment-other-receiver/_config.js
new file mode 100644
index 0000000000..8f023b602a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/class-private-state-increment-other-receiver/_config.js
@@ -0,0 +1,22 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	html: `<button>1</button><button>drop</button>`,
+
+	test({ assert, target }) {
+		const [bump, drop] = target.querySelectorAll('button');
+
+		bump?.click();
+		flushSync();
+		assert.htmlEqual(target.innerHTML, `<button>2</button><button>drop</button>`);
+
+		bump?.click();
+		flushSync();
+		assert.htmlEqual(target.innerHTML, `<button>3</button><button>drop</button>`);
+
+		drop?.click();
+		flushSync();
+		assert.htmlEqual(target.innerHTML, `<button>2</button><button>drop</button>`);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/class-private-state-increment-other-receiver/main.svelte b/packages/svelte/tests/runtime-runes/samples/class-private-state-increment-other-receiver/main.svelte
new file mode 100644
index 0000000000..67827aceee
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/class-private-state-increment-other-receiver/main.svelte
@@ -0,0 +1,23 @@
+<script>
+	class Counter {
+		#count = $state(1);
+
+		bump(other) {
+			other.#count++;
+		}
+
+		drop(other) {
+			--other.#count;
+		}
+
+		getCount() {
+			return this.#count;
+		}
+	}
+
+	const a = new Counter();
+	const b = new Counter();
+</script>
+
+<button onclick={() => a.bump(b)}>{b.getCount()}</button>
+<button onclick={() => a.drop(b)}>drop</button>

From 7725f77cca667aa1f7fb4b7b3219467f34e89313 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=EB=82=A8=EC=A0=95=EC=9A=B1?=
 <113816822+HelloWook@users.noreply.github.com>
Date: Fri, 14 Aug 2026 16:53:47 +0900
Subject: [PATCH 124/222] fix: apply CSS custom properties with falsy values on
 components (#18634)

---
 .changeset/css-props-falsy-values.md                 |  5 +++++
 .../src/internal/client/dom/blocks/css-props.js      |  6 +++---
 .../component-css-props-falsy/Component.svelte       |  1 +
 .../samples/component-css-props-falsy/_config.js     | 12 ++++++++++++
 .../samples/component-css-props-falsy/main.svelte    |  5 +++++
 5 files changed, 26 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/css-props-falsy-values.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/component-css-props-falsy/Component.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/component-css-props-falsy/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/component-css-props-falsy/main.svelte

diff --git a/.changeset/css-props-falsy-values.md b/.changeset/css-props-falsy-values.md
new file mode 100644
index 0000000000..677594ddaf
--- /dev/null
+++ b/.changeset/css-props-falsy-values.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: apply CSS custom properties with falsy values on components
diff --git a/packages/svelte/src/internal/client/dom/blocks/css-props.js b/packages/svelte/src/internal/client/dom/blocks/css-props.js
index 084a5561be..e5b5458d49 100644
--- a/packages/svelte/src/internal/client/dom/blocks/css-props.js
+++ b/packages/svelte/src/internal/client/dom/blocks/css-props.js
@@ -18,10 +18,10 @@ export function css_props(element, get_styles) {
 		for (var key in styles) {
 			var value = styles[key];
 
-			if (value) {
-				element.style.setProperty(key, value);
-			} else {
+			if (value == null || value === '') {
 				element.style.removeProperty(key);
+			} else {
+				element.style.setProperty(key, value);
 			}
 		}
 	});
diff --git a/packages/svelte/tests/runtime-runes/samples/component-css-props-falsy/Component.svelte b/packages/svelte/tests/runtime-runes/samples/component-css-props-falsy/Component.svelte
new file mode 100644
index 0000000000..0fd9beb678
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/component-css-props-falsy/Component.svelte
@@ -0,0 +1 @@
+<div>Hello</div>
diff --git a/packages/svelte/tests/runtime-runes/samples/component-css-props-falsy/_config.js b/packages/svelte/tests/runtime-runes/samples/component-css-props-falsy/_config.js
new file mode 100644
index 0000000000..78b14775e5
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/component-css-props-falsy/_config.js
@@ -0,0 +1,12 @@
+import { test } from '../../test';
+
+export default test({
+	ssrHtml: `<svelte-css-wrapper style="display: contents; --zero: 0; --one: 1;"><div>Hello</div></svelte-css-wrapper>`,
+
+	async test({ assert, target }) {
+		assert.htmlEqual(
+			target.innerHTML,
+			`<svelte-css-wrapper style="display: contents; --zero: 0; --one: 1;"><div>Hello</div></svelte-css-wrapper>`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/component-css-props-falsy/main.svelte b/packages/svelte/tests/runtime-runes/samples/component-css-props-falsy/main.svelte
new file mode 100644
index 0000000000..30c029b547
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/component-css-props-falsy/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Component from './Component.svelte';
+</script>
+
+<Component --zero={0} --one={1} --empty={''} --nullish={null} />

From 221dcae8ca50c84c99c9bf5475e91dc3aa25480e Mon Sep 17 00:00:00 2001
From: "svelte-triage-bot[bot]"
 <316883489+svelte-triage-bot[bot]@users.noreply.github.com>
Date: Fri, 14 Aug 2026 16:34:22 +0200
Subject: [PATCH 125/222] fix: preserve comment placement for server derived
 reads (#18641)

Fixes https://github.com/sveltejs/svelte/issues/18607.

For server output, `build_getter` reused a derived binding's declaration
identifier as the generated call callee. Esrap therefore associated
leading declaration comments with an earlier reference, potentially
emitting them immediately after `return` and triggering automatic
semicolon insertion. The getter returned `undefined` instead of the
derived value.

Fix it by avoiding the double-transform.

---------

Co-authored-by: svelte-triage-bot[bot] <316883489+svelte-triage-bot[bot]@users.noreply.github.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/tidy-cats-return.md                |  5 +
 .../server/visitors/shared/element.js         | 91 ++++++++++---------
 .../server/visitors/shared/utils.js           |  2 +-
 .../_config.js                                |  6 ++
 .../main.svelte                               | 14 +++
 5 files changed, 74 insertions(+), 44 deletions(-)
 create mode 100644 .changeset/tidy-cats-return.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/derived-forward-ref-leading-comments/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/derived-forward-ref-leading-comments/main.svelte

diff --git a/.changeset/tidy-cats-return.md b/.changeset/tidy-cats-return.md
new file mode 100644
index 0000000000..0c041196ef
--- /dev/null
+++ b/.changeset/tidy-cats-return.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: prevent declaration comments from breaking server derived references
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js
index 9c37b2fffe..6440510b01 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js
@@ -3,7 +3,7 @@
 /** @import { ComponentContext, ComponentServerTransformState } from '../../types.js' */
 import { is_event_attribute, is_text_attribute } from '../../../../../utils/ast.js';
 import { binding_properties } from '../../../../bindings.js';
-import { create_attribute, ExpressionMetadata, is_custom_element_node } from '../../../../nodes.js';
+import { ExpressionMetadata, is_custom_element_node } from '../../../../nodes.js';
 import { regex_starts_with_newline } from '../../../../patterns.js';
 import * as b from '#compiler/builders';
 import {
@@ -21,6 +21,11 @@ import { escape_html } from '../../../../../../escaping.js';
 
 const WHITESPACE_INSENSITIVE_ATTRIBUTES = ['class', 'style'];
 
+/**
+ * @typedef {{ type: 'transformed', name: string, expression: Expression }} TransformedAttribute
+ * An attribute whose expression has already been transformed and must not be visited again.
+ */
+
 /**
  * Writes the output to the template output. Some elements may have attributes on them that require the
  * their output to be the child content instead. In this case, an object is returned.
@@ -29,7 +34,7 @@ const WHITESPACE_INSENSITIVE_ATTRIBUTES = ['class', 'style'];
  * @param {(expression: Expression, metadata: ExpressionMetadata) => Expression} transform
  */
 export function build_element_attributes(node, context, transform) {
-	/** @type {Array<AST.Attribute | AST.SpreadAttribute>} */
+	/** @type {Array<AST.Attribute | AST.SpreadAttribute | TransformedAttribute>} */
 	const attributes = [];
 
 	/** @type {AST.ClassDirective[]} */
@@ -145,42 +150,26 @@ export function build_element_attributes(node, context, transform) {
 						attr.value[0].data === 'checkbox'
 				);
 
-				attributes.push(
-					create_attribute('checked', null, -1, -1, [
-						{
-							type: 'ExpressionTag',
-							start: -1,
-							end: -1,
-							expression: is_checkbox
-								? b.call(
-										b.member(attribute.expression, 'includes'),
-										build_attribute_value(value_attribute.value, context, transform)
-									)
-								: b.binary(
-										'===',
-										attribute.expression,
-										build_attribute_value(value_attribute.value, context, transform)
-									),
-							metadata: {
-								expression: new ExpressionMetadata()
-							}
-						}
-					])
-				);
+				attributes.push({
+					type: 'transformed',
+					name: 'checked',
+					expression: is_checkbox
+						? b.call(
+								b.member(expression, 'includes'),
+								build_attribute_value(value_attribute.value, context, transform)
+							)
+						: b.binary(
+								'===',
+								expression,
+								build_attribute_value(value_attribute.value, context, transform)
+							)
+				});
 			} else {
-				attributes.push(
-					create_attribute(attribute.name, null, -1, -1, [
-						{
-							type: 'ExpressionTag',
-							start: -1,
-							end: -1,
-							expression,
-							metadata: {
-								expression: new ExpressionMetadata()
-							}
-						}
-					])
-				);
+				attributes.push({
+					type: 'transformed',
+					name: get_attribute_name(node, attribute),
+					expression
+				});
 			}
 		} else if (attribute.type === 'SpreadAttribute') {
 			attributes.push(attribute);
@@ -217,7 +206,21 @@ export function build_element_attributes(node, context, transform) {
 	} else {
 		const css_hash = node.metadata.scoped ? context.state.analysis.css.hash : null;
 
-		for (const attribute of /** @type {AST.Attribute[]} */ (attributes)) {
+		for (const attribute of /** @type {Array<AST.Attribute | TransformedAttribute>} */ (
+			attributes
+		)) {
+			if (attribute.type === 'transformed') {
+				context.state.template.push(
+					b.call(
+						'$.attr',
+						b.literal(attribute.name),
+						attribute.expression,
+						is_boolean_attribute(attribute.name) && b.true
+					)
+				);
+				continue;
+			}
+
 			const name = get_attribute_name(node, attribute);
 			const can_use_literal =
 				(name !== 'class' || class_directives.length === 0) &&
@@ -298,14 +301,16 @@ function get_attribute_name(element, attribute) {
 
 /**
  * @param {AST.RegularElement | AST.SvelteElement} element
- * @param {Array<AST.Attribute | AST.SpreadAttribute | AST.BindDirective>} attributes
+ * @param {Array<AST.Attribute | AST.SpreadAttribute | AST.BindDirective | TransformedAttribute>} attributes
  * @param {ComponentContext} context
  * @param {(expression: Expression, metadata: ExpressionMetadata) => Expression} transform
  */
 export function build_spread_object(element, attributes, context, transform) {
 	const object = b.object(
 		attributes.map((attribute) => {
-			if (attribute.type === 'Attribute') {
+			if (attribute.type === 'transformed') {
+				return b.prop('init', b.key(attribute.name), attribute.expression);
+			} else if (attribute.type === 'Attribute') {
 				const name = get_attribute_name(element, attribute);
 				const value = build_attribute_value(
 					attribute.value,
@@ -340,7 +345,7 @@ export function build_spread_object(element, attributes, context, transform) {
 /**
  *
  * @param {AST.RegularElement | AST.SvelteElement} element
- * @param {Array<AST.Attribute | AST.SpreadAttribute>} attributes
+ * @param {Array<AST.Attribute | AST.SpreadAttribute | TransformedAttribute>} attributes
  * @param {AST.StyleDirective[]} style_directives
  * @param {AST.ClassDirective[]} class_directives
  * @param {ComponentContext} context
@@ -356,7 +361,7 @@ function build_element_spread_attributes(
 ) {
 	const args = prepare_element_spread(
 		element,
-		/** @type {Array<AST.Attribute | AST.SpreadAttribute | AST.BindDirective>} */ (attributes),
+		attributes,
 		style_directives,
 		class_directives,
 		context,
@@ -410,7 +415,7 @@ export function prepare_element_spread_object(element, context, transform) {
 /**
  * Prepare args for $.attributes(...): compute object, css_hash, classes, styles and flags.
  * @param {AST.RegularElement | AST.SvelteElement} element
- * @param {Array<AST.Attribute | AST.SpreadAttribute | AST.BindDirective>} attributes
+ * @param {Array<AST.Attribute | AST.SpreadAttribute | AST.BindDirective | TransformedAttribute>} attributes
  * @param {AST.StyleDirective[]} style_directives
  * @param {AST.ClassDirective[]} class_directives
  * @param {ComponentContext} context
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
index 56157cee37..28d2d762f9 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
@@ -286,7 +286,7 @@ export function build_getter(node, state) {
 	}
 
 	if (binding.kind === 'derived') {
-		return (binding.declaration_kind === 'var' ? b.maybe_call : b.call)(binding.node);
+		return (binding.declaration_kind === 'var' ? b.maybe_call : b.call)(node);
 	}
 
 	return node;
diff --git a/packages/svelte/tests/runtime-runes/samples/derived-forward-ref-leading-comments/_config.js b/packages/svelte/tests/runtime-runes/samples/derived-forward-ref-leading-comments/_config.js
new file mode 100644
index 0000000000..204581389d
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/derived-forward-ref-leading-comments/_config.js
@@ -0,0 +1,6 @@
+import { test } from '../../test';
+
+export default test({
+	ssrHtml: '<p>LATER</p> <input value="LATER">',
+	html: '<p>LATER</p> <input>'
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/derived-forward-ref-leading-comments/main.svelte b/packages/svelte/tests/runtime-runes/samples/derived-forward-ref-leading-comments/main.svelte
new file mode 100644
index 0000000000..f9a1a1a6fb
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/derived-forward-ref-leading-comments/main.svelte
@@ -0,0 +1,14 @@
+<script>
+	const ctx = {
+		get later() {
+			return later;
+		}
+	};
+
+	// a leading comment on the declaration
+	// that spans more than one line
+	let later = $derived.by(() => 'LATER');
+</script>
+
+<p>{ctx.later}</p>
+<input bind:value={later} />

From a224dd58671eb11f9b21e2a1c9f8fc48c0ece63a Mon Sep 17 00:00:00 2001
From: Yuuki Oohara <gmcthmy@gmail.com>
Date: Sat, 15 Aug 2026 01:07:16 +0900
Subject: [PATCH 126/222] fix: give effect teardowns the value from before the
 first write in a flush (#18620)

Fixes #18619

Make sure to not override old values with newer values that are part of the same flush

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/lucky-pears-smoke.md               |  5 +++++
 .../src/internal/client/reactivity/batch.js   |  1 +
 .../src/internal/client/reactivity/sources.js |  8 ++++++-
 .../_config.js                                | 17 +++++++++++++++
 .../main.svelte                               | 21 +++++++++++++++++++
 5 files changed, 51 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/lucky-pears-smoke.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/effect-teardown-multiple-writes/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/effect-teardown-multiple-writes/main.svelte

diff --git a/.changeset/lucky-pears-smoke.md b/.changeset/lucky-pears-smoke.md
new file mode 100644
index 0000000000..816a37dca5
--- /dev/null
+++ b/.changeset/lucky-pears-smoke.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: give effect teardowns the value from before the first write in a flush
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 5becae2dc9..8251f79298 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -420,6 +420,7 @@ export class Batch {
 		}
 
 		if (next_batch !== null) {
+			old_values.clear();
 			next_batch.#process();
 		}
 	}
diff --git a/packages/svelte/src/internal/client/reactivity/sources.js b/packages/svelte/src/internal/client/reactivity/sources.js
index 218941ab67..70be6489a4 100644
--- a/packages/svelte/src/internal/client/reactivity/sources.js
+++ b/packages/svelte/src/internal/client/reactivity/sources.js
@@ -180,7 +180,13 @@ export function set(source, value, should_proxy = false) {
  */
 export function internal_set(source, value, updated_during_traversal = null) {
 	if (!source.equals(value)) {
-		old_values.set(source, is_destroying_effect ? value : source.v);
+		if (is_destroying_effect) {
+			old_values.set(source, value);
+		} else if (!old_values.has(source)) {
+			// only record the value from before the first write in this flush, otherwise a
+			// teardown would see the value from before whichever write happened to be last
+			old_values.set(source, source.v);
+		}
 
 		var batch = Batch.ensure();
 		batch.capture(source, value);
diff --git a/packages/svelte/tests/runtime-runes/samples/effect-teardown-multiple-writes/_config.js b/packages/svelte/tests/runtime-runes/samples/effect-teardown-multiple-writes/_config.js
new file mode 100644
index 0000000000..7db4966106
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/effect-teardown-multiple-writes/_config.js
@@ -0,0 +1,17 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target, logs }) {
+		const button = target.querySelector('button');
+
+		flushSync(() => button?.click());
+
+		assert.deepEqual(logs, [
+			'register: one',
+			'unregister: one',
+			'leftover: none',
+			'register: three'
+		]);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/effect-teardown-multiple-writes/main.svelte b/packages/svelte/tests/runtime-runes/samples/effect-teardown-multiple-writes/main.svelte
new file mode 100644
index 0000000000..a3932aaa22
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/effect-teardown-multiple-writes/main.svelte
@@ -0,0 +1,21 @@
+<script>
+	let value = $state('one');
+
+	const registry = new Set();
+
+	$effect(() => {
+		registry.add(value);
+		console.log(`register: ${value}`);
+
+		return () => {
+			registry.delete(value);
+			console.log(`unregister: ${value}`);
+			console.log(`leftover: ${[...registry].join(', ') || 'none'}`);
+		};
+	});
+</script>
+
+<button onclick={() => {
+	value = 'two';
+	value = 'three';
+}}>go</button>

From c0987c09f816b5d7dcb5564d19c849f7e28b9e7a Mon Sep 17 00:00:00 2001
From: subotac <73706465+subotac@users.noreply.github.com>
Date: Fri, 14 Aug 2026 23:50:35 +0300
Subject: [PATCH 127/222]  fix: remove stale capture listeners from spread
 attributes (#18618)

Fixes #18608.

When `set_attributes` normalized removed spread attributes, it also
copied its internal `$$` listener bookkeeping keys into `next` with a
`null` value. This cleared the stored callback before event cleanup, so
removing a capture handler passed `null` to `removeEventListener` and
left the listener attached.

Skip internal `$$` keys during missing-attribute normalization. The
updated runtime-runes sample verifies replacing and then removing a
spread capture handler in both client and hydration modes.


---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/happy-spoons-talk.md               |  5 +++++
 .../client/dom/elements/attributes.js         |  3 ++-
 .../event-attribute-spread-update/_config.js  | 21 ++++++++++++++++---
 .../event-attribute-spread-update/main.svelte |  3 +++
 4 files changed, 28 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/happy-spoons-talk.md

diff --git a/.changeset/happy-spoons-talk.md b/.changeset/happy-spoons-talk.md
new file mode 100644
index 0000000000..cf165320db
--- /dev/null
+++ b/.changeset/happy-spoons-talk.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: clean up removed capture event handlers from spread attributes
diff --git a/packages/svelte/src/internal/client/dom/elements/attributes.js b/packages/svelte/src/internal/client/dom/elements/attributes.js
index 589685b5f2..8a25be7acd 100644
--- a/packages/svelte/src/internal/client/dom/elements/attributes.js
+++ b/packages/svelte/src/internal/client/dom/elements/attributes.js
@@ -315,7 +315,8 @@ function set_attributes(
 	var is_option_element = element.nodeName === OPTION_TAG;
 
 	for (var key in prev) {
-		if (!(key in next)) {
+		// don't null our internal $$onX listeners
+		if (!(key in next) && key[0] + key[1] !== '$$') {
 			next[key] = null;
 		}
 	}
diff --git a/packages/svelte/tests/runtime-runes/samples/event-attribute-spread-update/_config.js b/packages/svelte/tests/runtime-runes/samples/event-attribute-spread-update/_config.js
index af03eed4c9..5fbd37c768 100644
--- a/packages/svelte/tests/runtime-runes/samples/event-attribute-spread-update/_config.js
+++ b/packages/svelte/tests/runtime-runes/samples/event-attribute-spread-update/_config.js
@@ -3,16 +3,31 @@ import { test } from '../../test';
 
 export default test({
 	test({ assert, target }) {
-		const [change, increment] = target.querySelectorAll('button');
+		const [change, remove, increment] = target.querySelectorAll('button');
 
 		increment.click();
 		flushSync();
-		assert.htmlEqual(target.innerHTML, '<button>change handlers</button><button>1 / 1</button>');
+		assert.htmlEqual(
+			target.innerHTML,
+			'<button>change handlers</button><button>remove capture handler</button><button>1 / 1</button>'
+		);
 
 		change.click();
 		flushSync();
 		increment.click();
 		flushSync();
-		assert.htmlEqual(target.innerHTML, '<button>change handlers</button><button>3 / 3</button>');
+		assert.htmlEqual(
+			target.innerHTML,
+			'<button>change handlers</button><button>remove capture handler</button><button>3 / 3</button>'
+		);
+
+		remove.click();
+		flushSync();
+		increment.click();
+		flushSync();
+		assert.htmlEqual(
+			target.innerHTML,
+			'<button>change handlers</button><button>remove capture handler</button><button>5 / 3</button>'
+		);
 	}
 });
diff --git a/packages/svelte/tests/runtime-runes/samples/event-attribute-spread-update/main.svelte b/packages/svelte/tests/runtime-runes/samples/event-attribute-spread-update/main.svelte
index 32d4b242cc..ee049e469c 100644
--- a/packages/svelte/tests/runtime-runes/samples/event-attribute-spread-update/main.svelte
+++ b/packages/svelte/tests/runtime-runes/samples/event-attribute-spread-update/main.svelte
@@ -24,4 +24,7 @@
 >
 	change handlers
 </button>
+<button onclick={() => (attrs = { onclick: attrs.onclick, onclickcapture: undefined })}>
+	remove capture handler
+</button>
 <button {...attrs}>{delegated} / {non_delegated}</button>

From 248a2e1db4a497bc13cda883d1d8b2be4bb3a8e3 Mon Sep 17 00:00:00 2001
From: Yuichiro Yamashita <xydybaseball@gmail.com>
Date: Tue, 18 Aug 2026 21:26:56 +0900
Subject: [PATCH 128/222] fix: transform expressions inside labeled statements
 during server compilation (#18617)

close: #18615
---
 .changeset/clear-badgers-type.md                          | 5 +++++
 .../3-transform/server/visitors/LabeledStatement.js       | 1 +
 .../samples/labeled-statement-derived/_config.js          | 5 +++++
 .../samples/labeled-statement-derived/main.svelte         | 8 ++++++++
 4 files changed, 19 insertions(+)
 create mode 100644 .changeset/clear-badgers-type.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/labeled-statement-derived/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/labeled-statement-derived/main.svelte

diff --git a/.changeset/clear-badgers-type.md b/.changeset/clear-badgers-type.md
new file mode 100644
index 0000000000..3668aa7644
--- /dev/null
+++ b/.changeset/clear-badgers-type.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: transform expressions inside labeled statements during server compilation
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/LabeledStatement.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/LabeledStatement.js
index 83c828b839..e71e7473cd 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/LabeledStatement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/LabeledStatement.js
@@ -8,6 +8,7 @@ import * as b from '#compiler/builders';
  */
 export function LabeledStatement(node, context) {
 	if (context.state.analysis.runes || context.path.length > 1 || node.label.name !== '$') {
+		context.next();
 		return;
 	}
 
diff --git a/packages/svelte/tests/runtime-runes/samples/labeled-statement-derived/_config.js b/packages/svelte/tests/runtime-runes/samples/labeled-statement-derived/_config.js
new file mode 100644
index 0000000000..3507fb4707
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/labeled-statement-derived/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	html: '<p>correct</p>'
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/labeled-statement-derived/main.svelte b/packages/svelte/tests/runtime-runes/samples/labeled-statement-derived/main.svelte
new file mode 100644
index 0000000000..87cf8483f1
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/labeled-statement-derived/main.svelte
@@ -0,0 +1,8 @@
+<script>
+	let value = $derived(false);
+	let result = 'correct';
+
+	label: if (value) result = 'wrong';
+</script>
+
+<p>{result}</p>

From 9414eaa41b4a14109594589f275495aafff2968a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gautier=20Ben=20A=C3=AFm?=
 <48261497+GauBen@users.noreply.github.com>
Date: Tue, 18 Aug 2026 16:29:10 +0200
Subject: [PATCH 129/222] fix: prevent crash on async custom element attributes
 (#18661)

attributes setter logic wasn't async-aware

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/spotty-files-trade.md              |  5 +++
 .../client/visitors/RegularElement.js         | 15 ++++++-
 .../async-custom-element-attribute/_config.js | 11 +++++
 .../main.svelte                               | 41 +++++++++++++++++++
 .../_expected/client/main.svelte.js           |  2 +-
 5 files changed, 71 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/spotty-files-trade.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-custom-element-attribute/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-custom-element-attribute/main.svelte

diff --git a/.changeset/spotty-files-trade.md b/.changeset/spotty-files-trade.md
new file mode 100644
index 0000000000..39975b7a9a
--- /dev/null
+++ b/.changeset/spotty-files-trade.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: allow custom elements to receive async values as props
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
index 8dcd3c7d6f..1cf5abeb69 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
@@ -664,14 +664,25 @@ function build_element_attribute_update(element, node_id, name, value, attribute
  * @param {ComponentContext} context
  */
 function build_custom_element_attribute_update_assignment(node_id, attribute, context) {
-	const { value, has_state } = build_attribute_value(attribute.value, context);
+	const memoizer = new Memoizer();
+	const { value, has_state } = build_attribute_value(attribute.value, context, (value, metadata) =>
+		memoizer.add(value, metadata)
+	);
 
 	// don't lowercase name, as we set the element's property, which might be case sensitive
 	const call = b.call('$.set_custom_element_data', node_id, b.literal(attribute.name), value);
 
 	// this is different from other updates — it doesn't get grouped,
 	// because set_custom_element_data may not be idempotent
-	const update = has_state ? b.call('$.template_effect', b.thunk(call)) : call;
+	const update = has_state
+		? b.call(
+				'$.template_effect',
+				b.arrow(memoizer.apply(), call),
+				memoizer.sync_values(),
+				memoizer.async_values(),
+				memoizer.blockers()
+			)
+		: call;
 
 	context.state.init.push(b.stmt(update));
 }
diff --git a/packages/svelte/tests/runtime-runes/samples/async-custom-element-attribute/_config.js b/packages/svelte/tests/runtime-runes/samples/async-custom-element-attribute/_config.js
new file mode 100644
index 0000000000..788573d7cf
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-custom-element-attribute/_config.js
@@ -0,0 +1,11 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ target, assert }) {
+		await tick();
+		const [element] = target.querySelectorAll('async-custom-element');
+
+		assert.htmlEqual(element.innerHTML, `Hello foobar!`);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-custom-element-attribute/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-custom-element-attribute/main.svelte
new file mode 100644
index 0000000000..a047054069
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-custom-element-attribute/main.svelte
@@ -0,0 +1,41 @@
+<script>
+	class MyCustomElement extends HTMLElement {
+		constructor() {
+			super();
+			this._foo = null;
+			this._bar = null;
+		}
+
+		/**
+		 * @param {string} foo
+		 */
+		set foo(foo) {
+			this._foo = foo;
+			this.render();
+		}
+
+		/**
+		 * @param {string} foo
+		 */
+		set bar(bar) {
+			this._bar = bar;
+			this.render();
+		}
+
+		connectedCallback() {
+			this.render();
+		}
+
+		render() {
+			this.innerHTML = "Hello " + this._foo + this._bar + "!";
+		}
+	}
+
+	if (!customElements.get('async-custom-element')) {
+		customElements.define("async-custom-element", MyCustomElement);
+	}
+
+	const foo = $derived(await "foo");
+</script>
+
+<async-custom-element {foo} bar={await 'bar'}></async-custom-element>
diff --git a/packages/svelte/tests/snapshot/samples/dynamic-attributes-casing/_expected/client/main.svelte.js b/packages/svelte/tests/snapshot/samples/dynamic-attributes-casing/_expected/client/main.svelte.js
index eafadfc2ea..799c9f2139 100644
--- a/packages/svelte/tests/snapshot/samples/dynamic-attributes-casing/_expected/client/main.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/dynamic-attributes-casing/_expected/client/main.svelte.js
@@ -25,7 +25,7 @@ export default function Main($$anchor) {
 	var svg_1 = $.sibling(div_1, 2);
 	var custom_element_1 = $.sibling(svg_1, 2);
 
-	$.template_effect(() => $.set_custom_element_data(custom_element_1, 'fooBar', y()));
+	$.template_effect(($0) => $.set_custom_element_data(custom_element_1, 'fooBar', $0), [() => y()]);
 
 	$.template_effect(
 		($0, $1) => {

From a5ea12ee9313cf3f117b43ca38d3a594b888cbb2 Mon Sep 17 00:00:00 2001
From: Siddhesh Kabra <146343711+Xsidz@users.noreply.github.com>
Date: Tue, 18 Aug 2026 21:04:51 +0530
Subject: [PATCH 130/222] fix: skip Program comment nodes in migration to
 prevent crash (#18656)

Fixes #18304

The parent of a declaration could be the Program, on which HTML comments are added, which subsequently crashes the funciton. Ignore such comments.

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/fix-migrate-comment-no-position.md              | 5 +++++
 packages/svelte/src/compiler/migrate/index.js              | 7 ++++++-
 .../tests/migrate/samples/props-export-alias/input.svelte  | 1 +
 .../tests/migrate/samples/props-export-alias/output.svelte | 1 +
 4 files changed, 13 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/fix-migrate-comment-no-position.md

diff --git a/.changeset/fix-migrate-comment-no-position.md b/.changeset/fix-migrate-comment-no-position.md
new file mode 100644
index 0000000000..fa9981dc60
--- /dev/null
+++ b/.changeset/fix-migrate-comment-no-position.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: ignore comments of Program node during migration script
diff --git a/packages/svelte/src/compiler/migrate/index.js b/packages/svelte/src/compiler/migrate/index.js
index 0370155c12..3baef3ecae 100644
--- a/packages/svelte/src/compiler/migrate/index.js
+++ b/packages/svelte/src/compiler/migrate/index.js
@@ -1590,7 +1590,12 @@ function migrate_slot_usage(node, path, state) {
  */
 function extract_type_and_comment(declarator, state, path) {
 	const str = state.str;
-	const parent = path.at(-1);
+	let parent = path.at(-1);
+
+	if (parent?.type === 'Program') {
+		// We don't want comments from the program node
+		parent = undefined;
+	}
 
 	// Try to find jsdoc above the declaration
 	let comment_node = /** @type {Node} */ (parent)?.leadingComments?.at(-1);
diff --git a/packages/svelte/tests/migrate/samples/props-export-alias/input.svelte b/packages/svelte/tests/migrate/samples/props-export-alias/input.svelte
index 1cb57ef5fd..fc06166e21 100644
--- a/packages/svelte/tests/migrate/samples/props-export-alias/input.svelte
+++ b/packages/svelte/tests/migrate/samples/props-export-alias/input.svelte
@@ -1,3 +1,4 @@
+<!-- @component x -->
 <script lang="ts">
 	let klass = '';
 	export { klass as class }
diff --git a/packages/svelte/tests/migrate/samples/props-export-alias/output.svelte b/packages/svelte/tests/migrate/samples/props-export-alias/output.svelte
index c697083b28..433a9d04ed 100644
--- a/packages/svelte/tests/migrate/samples/props-export-alias/output.svelte
+++ b/packages/svelte/tests/migrate/samples/props-export-alias/output.svelte
@@ -1,3 +1,4 @@
+<!-- @component x -->
 <script lang="ts">
 	interface Props {
 		class?: string;

From 384ee73aa27b41beb214fe5f3e4cc4339b489ddd Mon Sep 17 00:00:00 2001
From: subotac <73706465+subotac@users.noreply.github.com>
Date: Wed, 19 Aug 2026 05:18:47 +0300
Subject: [PATCH 131/222] fix: preserve logical assignments to private state
 fields (#18594)

Fixes #18592.

Logical assignments to private `$state` fields were compiled as
unconditional setter calls. This preserves JavaScript short-circuiting
by evaluating the setter only when `||=`, `&&=`, or `??=` should assign.

The regression sample covers the no-assignment branch for all three
operators, alongside the existing assignment-path coverage.

### Before submitting the PR, please make sure you do the following

- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).

### Tests and linting

- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
---
 .changeset/tidy-ravens-assign.md              |  5 ++++
 .../client/visitors/AssignmentExpression.js   | 19 ++++++++++++---
 .../_config.js                                |  5 ++++
 .../main.svelte                               | 24 +++++++++++++++++++
 4 files changed, 50 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/tidy-ravens-assign.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/class-private-fields-logical-assignment/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/class-private-fields-logical-assignment/main.svelte

diff --git a/.changeset/tidy-ravens-assign.md b/.changeset/tidy-ravens-assign.md
new file mode 100644
index 0000000000..312adde9b5
--- /dev/null
+++ b/.changeset/tidy-ravens-assign.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: preserve short-circuiting for logical assignments to private state fields
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/AssignmentExpression.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/AssignmentExpression.js
index e66e3408e2..7ab148f0a3 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/AssignmentExpression.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/AssignmentExpression.js
@@ -1,4 +1,4 @@
-/** @import { AssignmentExpression, AssignmentOperator, Expression, Identifier, Pattern } from 'estree' */
+/** @import { AssignmentExpression, AssignmentOperator, Expression, Identifier, LogicalOperator, Pattern } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { Context } from '../types.js' */
 import * as b from '#compiler/builders';
@@ -79,8 +79,13 @@ function build_assignment(operator, left, right, context) {
 
 			// special case — assignment to private state field
 			if (left.property.type === 'PrivateIdentifier') {
+				const logical_operator = ['||=', '&&=', '??='].includes(operator)
+					? /** @type {LogicalOperator} */ (operator.slice(0, -1))
+					: null;
 				let value = /** @type {Expression} */ (
-					context.visit(build_assignment_value(operator, left, right))
+					context.visit(
+						logical_operator === null ? build_assignment_value(operator, left, right) : right
+					)
 				);
 
 				const needs_proxy =
@@ -88,7 +93,15 @@ function build_assignment(operator, left, right, context) {
 					is_non_coercive_operator(operator) &&
 					should_proxy(value, context.state.scope);
 
-				return b.call('$.set', left, value, needs_proxy && b.true);
+				const assignment = b.call('$.set', left, value, needs_proxy && b.true);
+
+				return logical_operator === null
+					? assignment
+					: b.logical(
+							logical_operator,
+							/** @type {Expression} */ (context.visit(left)),
+							assignment
+						);
 			}
 		}
 	}
diff --git a/packages/svelte/tests/runtime-runes/samples/class-private-fields-logical-assignment/_config.js b/packages/svelte/tests/runtime-runes/samples/class-private-fields-logical-assignment/_config.js
new file mode 100644
index 0000000000..d919c18396
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/class-private-fields-logical-assignment/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	html: `<p>truthy||value</p>`
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/class-private-fields-logical-assignment/main.svelte b/packages/svelte/tests/runtime-runes/samples/class-private-fields-logical-assignment/main.svelte
new file mode 100644
index 0000000000..cc74150b35
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/class-private-fields-logical-assignment/main.svelte
@@ -0,0 +1,24 @@
+<script>
+	class Values {
+		#or = $state.raw('truthy');
+		#and = $state.raw('');
+		#nullish = $state.raw('value');
+
+		get or() {
+			return (this.#or ||= 'assigned');
+		}
+
+		get and() {
+			return (this.#and &&= 'assigned');
+		}
+
+		get nullish() {
+			return (this.#nullish ??= 'assigned');
+		}
+	}
+
+	const values = new Values();
+	const result = $derived([values.or, values.and, values.nullish]);
+</script>
+
+<p>{result.join('|')}</p>

From fe4a56b0a8b065777c4f01dab63e4fbd260ef758 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gautier=20Ben=20A=C3=AFm?=
 <48261497+GauBen@users.noreply.github.com>
Date: Wed, 19 Aug 2026 16:06:15 +0200
Subject: [PATCH 132/222] fix: avoid double-calling a derived reference when
 destructuring (#18668)

Hi! This PR fixes #18666

### Before submitting the PR, please make sure you do the following

- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).

### Tests and linting

- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
---
 .changeset/nervous-dolls-clean.md                         | 5 +++++
 .../3-transform/server/visitors/VariableDeclaration.js    | 6 ++++--
 .../samples/derived-destructured-from-derived/_config.js  | 5 +++++
 .../samples/derived-destructured-from-derived/main.svelte | 8 ++++++++
 4 files changed, 22 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/nervous-dolls-clean.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/derived-destructured-from-derived/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/derived-destructured-from-derived/main.svelte

diff --git a/.changeset/nervous-dolls-clean.md b/.changeset/nervous-dolls-clean.md
new file mode 100644
index 0000000000..5b31bdd3c7
--- /dev/null
+++ b/.changeset/nervous-dolls-clean.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: avoid double-calling a derived reference when destructuring `$derived` of another `$derived` during server-side rendering
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/VariableDeclaration.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/VariableDeclaration.js
index 2c7b14afa5..108f65a884 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/VariableDeclaration.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/VariableDeclaration.js
@@ -102,9 +102,11 @@ export function VariableDeclaration(node, context) {
 				} else {
 					const call = /** @type {CallExpression} */ (declarator.init);
 
-					let rhs = value;
+					// - cannot be a SpreadElement because refused during analysis
+					// - use args[0] rather than value to avoid visiting twice (above in const value = ... and below in for-ofs)
+					let rhs = /** @type {Expression} */ (call.arguments[0]);
 
-					if (rune !== '$derived' || call.arguments[0].type !== 'Identifier') {
+					if (rune === '$derived.by' || call.arguments[0].type !== 'Identifier') {
 						const id = b.id(context.state.scope.generate('$$d'));
 
 						rhs = b.call(id);
diff --git a/packages/svelte/tests/runtime-runes/samples/derived-destructured-from-derived/_config.js b/packages/svelte/tests/runtime-runes/samples/derived-destructured-from-derived/_config.js
new file mode 100644
index 0000000000..a36c2adf7d
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/derived-destructured-from-derived/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	html: `<button>3</button>`
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/derived-destructured-from-derived/main.svelte b/packages/svelte/tests/runtime-runes/samples/derived-destructured-from-derived/main.svelte
new file mode 100644
index 0000000000..b1882243f4
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/derived-destructured-from-derived/main.svelte
@@ -0,0 +1,8 @@
+<script>
+	let name = $state('foo');
+	const foo = $derived(name);
+	const { length } = $derived(foo);
+</script>
+
+<!-- only needed to prevent constant folding, never run -->
+<button onclick={() => (name = 'longer')}>{length}</button>

From 8835003d41d23751d64e99492b7548ca554abd76 Mon Sep 17 00:00:00 2001
From: Marwan <145616984+marwan562@users.noreply.github.com>
Date: Thu, 20 Aug 2026 00:13:06 +0300
Subject: [PATCH 133/222] fix: preserve CSS escape sequences when printing
 selectors (#18667)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Fixes #18664

`print()` was writing selector names back out verbatim. The parser
decodes CSS escape sequences when it reads them — `\31` becomes `1`,
`\a` becomes a newline — so the printer produced selectors that either
failed to re-parse (`#123`) or silently meant something different
(`#line\nbreak` turns into a descendant combinator).

A small re-escaper (`escape_identifier`) is now used when printing type,
class, id, pseudo, attribute and at-rule names.

Also fixes a backslash parser bug in the process.

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/calm-foxes-reprint.md              |  5 ++
 .../src/compiler/phases/1-parse/read/style.js |  3 +-
 packages/svelte/src/compiler/print/index.js   | 76 +++++++++++++++--
 .../samples/css-escape-sequences/input.svelte | 25 ++++++
 .../css-escape-sequences/output.svelte        | 83 +++++++++++++++++++
 packages/svelte/tests/print/test.ts           |  4 +
 6 files changed, 188 insertions(+), 8 deletions(-)
 create mode 100644 .changeset/calm-foxes-reprint.md
 create mode 100644 packages/svelte/tests/print/samples/css-escape-sequences/input.svelte
 create mode 100644 packages/svelte/tests/print/samples/css-escape-sequences/output.svelte

diff --git a/.changeset/calm-foxes-reprint.md b/.changeset/calm-foxes-reprint.md
new file mode 100644
index 0000000000..08ea964bfe
--- /dev/null
+++ b/.changeset/calm-foxes-reprint.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: preserve CSS escape sequences when printing selectors
\ No newline at end of file
diff --git a/packages/svelte/src/compiler/phases/1-parse/read/style.js b/packages/svelte/src/compiler/phases/1-parse/read/style.js
index 5eb8c2b3e9..02e6d8d064 100644
--- a/packages/svelte/src/compiler/phases/1-parse/read/style.js
+++ b/packages/svelte/src/compiler/phases/1-parse/read/style.js
@@ -614,7 +614,8 @@ function read_identifier(parser) {
 		if (char === '\\') {
 			const sequence = parser.match_regex(REGEX_UNICODE_SEQUENCE);
 			if (sequence) {
-				identifier += String.fromCodePoint(parseInt(sequence.slice(1), 16));
+				const character = String.fromCodePoint(parseInt(sequence.slice(1), 16));
+				identifier += character === '\\' ? '\\\\' : character;
 				parser.index += sequence.length;
 			} else {
 				identifier += '\\' + parser.template[parser.index + 1];
diff --git a/packages/svelte/src/compiler/print/index.js b/packages/svelte/src/compiler/print/index.js
index 8759fe3013..c6964fc0b7 100644
--- a/packages/svelte/src/compiler/print/index.js
+++ b/packages/svelte/src/compiler/print/index.js
@@ -7,6 +7,68 @@ import { is_void } from '../../utils.js';
 /** Threshold for when content should be formatted on separate lines */
 const LINE_BREAK_THRESHOLD = 50;
 
+/** Characters that are valid in a CSS identifier without escaping */
+const REGEX_IDENTIFIER_CHAR = /^[a-zA-Z0-9_-]$/;
+
+/** Hex digits — a backslash followed by one of these is read as a hex escape */
+const REGEX_HEX_DIGIT = /[0-9a-fA-F]/;
+
+/**
+ * Re-escape a CSS identifier name so that it prints as valid CSS.
+ *
+ * `parse` decodes CSS escape sequences when building the AST — `\31` becomes `1`,
+ * `\a` becomes a newline — but keeps single-character escapes such as `\.` and
+ * escaped backslashes intact. When printing we therefore only need to escape the
+ * characters that would be illegal in a bare identifier: a leading digit, `-`
+ * followed by a digit, whitespace and control characters, and anything else that
+ * is not already escaped.
+ * @param {string} name
+ */
+function escape_identifier(name) {
+	let escaped = '';
+	let i = 0;
+
+	while (i < name.length) {
+		const char = name[i];
+
+		if (char === '\\') {
+			const next = name.charAt(i + 1);
+			if (next === '' || REGEX_HEX_DIGIT.test(next)) {
+				// A literal backslash in a name must itself be escaped: `\5c `
+				// re-parses to a backslash, whereas a backslash followed by a hex
+				// digit (or by nothing) would be read back as a hex escape.
+				escaped += '\\5c ';
+				i += 1;
+				continue;
+			}
+
+			// Already escaped — copy the backslash and the escaped character as-is.
+			escaped += '\\' + next;
+			i += 2;
+			continue;
+		}
+
+		const code = /** @type {number} */ (char.codePointAt(0));
+		const is_leading_digit = i === 0 && char >= '0' && char <= '9';
+		const is_leading_hyphen_digit =
+			i === 0 && char === '-' && name.charAt(i + 1) >= '0' && name.charAt(i + 1) <= '9';
+
+		if (
+			is_leading_digit ||
+			is_leading_hyphen_digit ||
+			!(REGEX_IDENTIFIER_CHAR.test(char) || code >= 160)
+		) {
+			escaped += `\\${code.toString(16)} `;
+		} else {
+			escaped += char;
+		}
+
+		i += 1;
+	}
+
+	return escaped;
+}
+
 /**
  * `print` converts a Svelte AST node back into Svelte source code.
  * It is primarily intended for tools that parse and transform components using the compiler’s modern AST representation.
@@ -324,7 +386,7 @@ function css_visitors(comments, js_comments) {
 
 	return {
 		Atrule(node, context) {
-			context.write(`@${node.name}`);
+			context.write(`@${escape_identifier(node.name)}`);
 
 			const prelude_end = node.block?.start ?? node.end;
 			if (node.prelude || has_comment_before(prelude_end)) {
@@ -341,7 +403,7 @@ function css_visitors(comments, js_comments) {
 		},
 
 		AttributeSelector(node, context) {
-			context.write(`[${node.name}`);
+			context.write(`[${escape_identifier(node.name)}`);
 			if (node.matcher) {
 				context.write(node.matcher);
 				context.write(`"${node.value}"`);
@@ -365,7 +427,7 @@ function css_visitors(comments, js_comments) {
 		},
 
 		ClassSelector(node, context) {
-			context.write(`.${node.name}`);
+			context.write(`.${escape_identifier(node.name)}`);
 		},
 
 		ComplexSelector(node, context) {
@@ -379,7 +441,7 @@ function css_visitors(comments, js_comments) {
 		},
 
 		IdSelector(node, context) {
-			context.write(`#${node.name}`);
+			context.write(`#${escape_identifier(node.name)}`);
 		},
 
 		NestingSelector(node, context) {
@@ -395,7 +457,7 @@ function css_visitors(comments, js_comments) {
 		},
 
 		PseudoClassSelector(node, context) {
-			context.write(`:${node.name}`);
+			context.write(`:${escape_identifier(node.name)}`);
 
 			if (node.args) {
 				context.write('(');
@@ -409,7 +471,7 @@ function css_visitors(comments, js_comments) {
 		},
 
 		PseudoElementSelector(node, context) {
-			context.write(`::${node.name}`);
+			context.write(`::${escape_identifier(node.name)}`);
 			if (node.args) {
 				context.write('(');
 				context.visit(node.args);
@@ -458,7 +520,7 @@ function css_visitors(comments, js_comments) {
 		},
 
 		TypeSelector(node, context) {
-			context.write(node.name);
+			context.write(node.name === '*' ? node.name : escape_identifier(node.name));
 		}
 	};
 }
diff --git a/packages/svelte/tests/print/samples/css-escape-sequences/input.svelte b/packages/svelte/tests/print/samples/css-escape-sequences/input.svelte
new file mode 100644
index 0000000000..db8e3e16a5
--- /dev/null
+++ b/packages/svelte/tests/print/samples/css-escape-sequences/input.svelte
@@ -0,0 +1,25 @@
+<div></div>
+
+<style>
+	#\31\32\33 { color: green; }
+	#\31 23 { color: green; }
+	#line\a break { color: green; }
+	#line\a
+break { color: green; }
+	li\.foo { color: green; }
+	.a\1f642 b { color: green; }
+	.a🙂b { color: green; }
+	#\2d 1foo { color: red; }
+	.a\5c b { color: red; }
+	.a\\b { color: red; }
+	.a\5c q { color: red; }
+	.a\\q { color: red; }
+	.a\5c  { color: red; }
+	.a\\ { color: red; }
+	#\5c a { color: red; }
+	[\31 data] { color: red; }
+	:\31 st-child { color: red; }
+	* { color: red; }
+	#id-selector { color: red; }
+	[data-attribute="value"] { color: red; }
+</style>
diff --git a/packages/svelte/tests/print/samples/css-escape-sequences/output.svelte b/packages/svelte/tests/print/samples/css-escape-sequences/output.svelte
new file mode 100644
index 0000000000..532d0a2562
--- /dev/null
+++ b/packages/svelte/tests/print/samples/css-escape-sequences/output.svelte
@@ -0,0 +1,83 @@
+<div></div>
+
+<style>
+	#\31 23 {
+		color: green;
+	}
+
+	#\31 23 {
+		color: green;
+	}
+
+	#line\a break {
+		color: green;
+	}
+
+	#line\a break {
+		color: green;
+	}
+
+	li\.foo {
+		color: green;
+	}
+
+	.a🙂b {
+		color: green;
+	}
+
+	.a🙂b {
+		color: green;
+	}
+
+	#\2d 1foo {
+		color: red;
+	}
+
+	.a\\b {
+		color: red;
+	}
+
+	.a\\b {
+		color: red;
+	}
+
+	.a\\q {
+		color: red;
+	}
+
+	.a\\q {
+		color: red;
+	}
+
+	.a\\ {
+		color: red;
+	}
+
+	.a\\ {
+		color: red;
+	}
+
+	#\\a {
+		color: red;
+	}
+
+	[\31 data] {
+		color: red;
+	}
+
+	:\31 st-child {
+		color: red;
+	}
+
+	* {
+		color: red;
+	}
+
+	#id-selector {
+		color: red;
+	}
+
+	[data-attribute="value"] {
+		color: red;
+	}
+</style>
diff --git a/packages/svelte/tests/print/test.ts b/packages/svelte/tests/print/test.ts
index aa007a7a54..4caecf90ae 100644
--- a/packages/svelte/tests/print/test.ts
+++ b/packages/svelte/tests/print/test.ts
@@ -12,6 +12,10 @@ const { test, run } = suite<PrintTest>(async (config, cwd) => {
 	const output = print(ast);
 	const outputCode = output.code.endsWith('\n') ? output.code : output.code + '\n';
 
+	// the printed output must itself be valid Svelte — `print` should never emit
+	// code that `parse` cannot read back (e.g. CSS escape sequences must round-trip)
+	parse(outputCode, { modern: true });
+
 	// run `UPDATE_SNAPSHOTS=true pnpm test print` to update print tests
 	if (process.env.UPDATE_SNAPSHOTS) {
 		fs.writeFileSync(`${cwd}/output.svelte`, outputCode);

From 19aa51d443474fd89592a55c3d3aa0ccc5c240e2 Mon Sep 17 00:00:00 2001
From: Madan kumar <winklemad@outlook.com>
Date: Thu, 20 Aug 2026 02:46:23 +0530
Subject: [PATCH 134/222] fix: print `{#await ... catch}` et al correctly
 (#18645)

needs to check the error value, not the then value

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/eighty-pugs-shave.md               |  5 ++++
 packages/svelte/src/compiler/print/index.js   |  2 +-
 .../print/samples/await-block/input.svelte    | 26 +++++++++++++++++++
 .../print/samples/await-block/output.svelte   | 26 +++++++++++++++++++
 4 files changed, 58 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/eighty-pugs-shave.md

diff --git a/.changeset/eighty-pugs-shave.md b/.changeset/eighty-pugs-shave.md
new file mode 100644
index 0000000000..0f0eaf9a6c
--- /dev/null
+++ b/.changeset/eighty-pugs-shave.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: correctly print `{#await ... catch x}` et al
diff --git a/packages/svelte/src/compiler/print/index.js b/packages/svelte/src/compiler/print/index.js
index c6964fc0b7..a3e10085de 100644
--- a/packages/svelte/src/compiler/print/index.js
+++ b/packages/svelte/src/compiler/print/index.js
@@ -763,7 +763,7 @@ const svelte_visitors = (comments, state) => ({
 		}
 
 		if (node.catch) {
-			context.write(node.value ? 'catch ' : 'catch');
+			context.write(node.error ? 'catch ' : 'catch');
 			if (node.error) context.visit(node.error);
 			context.write('}');
 
diff --git a/packages/svelte/tests/print/samples/await-block/input.svelte b/packages/svelte/tests/print/samples/await-block/input.svelte
index 10f0b3fb9e..ba0ba8c882 100644
--- a/packages/svelte/tests/print/samples/await-block/input.svelte
+++ b/packages/svelte/tests/print/samples/await-block/input.svelte
@@ -8,3 +8,29 @@
 	<!-- promise was rejected -->
 	<p>Something went wrong: {error.message}</p>
 {/await}
+
+{#await promise catch error}
+	<p>The error is {error}</p>
+{/await}
+
+{#await promise then value}
+	<p>The value is {value}</p>
+{/await}
+
+{#await promise catch}
+	<p>Something went wrong</p>
+{/await}
+
+{#await promise}
+	<p>waiting for the promise to resolve...</p>
+{:then}
+	<p>the promise resolved</p>
+{:catch error}
+	<p>The error is {error}</p>
+{/await}
+
+{#await promise}
+	<p>waiting for the promise to resolve...</p>
+{:catch}
+	<p>Something went wrong</p>
+{/await}
diff --git a/packages/svelte/tests/print/samples/await-block/output.svelte b/packages/svelte/tests/print/samples/await-block/output.svelte
index 10f0b3fb9e..ba0ba8c882 100644
--- a/packages/svelte/tests/print/samples/await-block/output.svelte
+++ b/packages/svelte/tests/print/samples/await-block/output.svelte
@@ -8,3 +8,29 @@
 	<!-- promise was rejected -->
 	<p>Something went wrong: {error.message}</p>
 {/await}
+
+{#await promise catch error}
+	<p>The error is {error}</p>
+{/await}
+
+{#await promise then value}
+	<p>The value is {value}</p>
+{/await}
+
+{#await promise catch}
+	<p>Something went wrong</p>
+{/await}
+
+{#await promise}
+	<p>waiting for the promise to resolve...</p>
+{:then}
+	<p>the promise resolved</p>
+{:catch error}
+	<p>The error is {error}</p>
+{/await}
+
+{#await promise}
+	<p>waiting for the promise to resolve...</p>
+{:catch}
+	<p>Something went wrong</p>
+{/await}

From 9c2494b134717141186887fab011972b9293d4ea Mon Sep 17 00:00:00 2001
From: "svelte-triage-bot[bot]"
 <316883489+svelte-triage-bot[bot]@users.noreply.github.com>
Date: Thu, 20 Aug 2026 10:42:04 +0200
Subject: [PATCH 135/222] fix: preserve namespaces in CSS type selectors
 (#18678)

Fixes #18677.

- preserve namespace prefixes on CSS `TypeSelector` AST nodes
- accept wildcard local names in `svg|*` and `*|*`
- retain namespaces when printing modern ASTs
- keep namespaced universal selectors intact while adding scoped CSS
selectors
- add compile and print regressions covering all four namespace forms

---------

Co-authored-by: svelte-triage-bot <team@svelte.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/pink-chairs-matter.md              |  5 +++++
 .../src/compiler/phases/1-parse/read/style.js | 14 +++++++++----
 .../compiler/phases/3-transform/css/index.js  |  6 +++++-
 packages/svelte/src/compiler/print/index.js   |  4 ++++
 packages/svelte/src/compiler/types/css.d.ts   |  1 +
 .../namespaced-type-selector/expected.css     | 17 +++++++++++++++
 .../namespaced-type-selector/input.svelte     | 21 +++++++++++++++++++
 .../css-namespaced-type-selector/input.svelte | 10 +++++++++
 .../output.svelte                             | 12 +++++++++++
 packages/svelte/types/index.d.ts              |  1 +
 10 files changed, 86 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/pink-chairs-matter.md
 create mode 100644 packages/svelte/tests/css/samples/namespaced-type-selector/expected.css
 create mode 100644 packages/svelte/tests/css/samples/namespaced-type-selector/input.svelte
 create mode 100644 packages/svelte/tests/print/samples/css-namespaced-type-selector/input.svelte
 create mode 100644 packages/svelte/tests/print/samples/css-namespaced-type-selector/output.svelte

diff --git a/.changeset/pink-chairs-matter.md b/.changeset/pink-chairs-matter.md
new file mode 100644
index 0000000000..6a8a6e75f3
--- /dev/null
+++ b/.changeset/pink-chairs-matter.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: preserve namespaces in CSS type selectors
diff --git a/packages/svelte/src/compiler/phases/1-parse/read/style.js b/packages/svelte/src/compiler/phases/1-parse/read/style.js
index 02e6d8d064..a07d7f6fea 100644
--- a/packages/svelte/src/compiler/phases/1-parse/read/style.js
+++ b/packages/svelte/src/compiler/phases/1-parse/read/style.js
@@ -204,15 +204,18 @@ function read_selector(parser, inside_pseudo_class = false) {
 			});
 		} else if (parser.eat('*')) {
 			let name = '*';
+			/** @type {string | undefined} */
+			let namespace;
 
 			if (parser.eat('|')) {
-				// * is the namespace (which we ignore)
-				name = read_identifier(parser);
+				namespace = name;
+				name = parser.eat('*') ? '*' : read_identifier(parser);
 			}
 
 			relative_selector.selectors.push({
 				type: 'TypeSelector',
 				name,
+				...(namespace !== undefined && { namespace }),
 				start,
 				end: parser.index
 			});
@@ -314,15 +317,18 @@ function read_selector(parser, inside_pseudo_class = false) {
 			});
 		} else if (!parser.match_regex(REGEX_COMBINATOR)) {
 			let name = read_identifier(parser);
+			/** @type {string | undefined} */
+			let namespace;
 
 			if (parser.eat('|')) {
-				// we ignore the namespace when trying to find matching element classes
-				name = read_identifier(parser);
+				namespace = name;
+				name = parser.eat('*') ? '*' : read_identifier(parser);
 			}
 
 			relative_selector.selectors.push({
 				type: 'TypeSelector',
 				name,
+				...(namespace !== undefined && { namespace }),
 				start,
 				end: parser.index
 			});
diff --git a/packages/svelte/src/compiler/phases/3-transform/css/index.js b/packages/svelte/src/compiler/phases/3-transform/css/index.js
index 537ab60a0e..bfeb426493 100644
--- a/packages/svelte/src/compiler/phases/3-transform/css/index.js
+++ b/packages/svelte/src/compiler/phases/3-transform/css/index.js
@@ -355,7 +355,11 @@ const visitors = {
 						continue;
 					}
 
-					if (selector.type === 'TypeSelector' && selector.name === '*') {
+					if (
+						selector.type === 'TypeSelector' &&
+						selector.name === '*' &&
+						selector.namespace === undefined
+					) {
 						context.state.code.update(selector.start, selector.end, modifier);
 					} else {
 						context.state.code.appendLeft(selector.end, modifier);
diff --git a/packages/svelte/src/compiler/print/index.js b/packages/svelte/src/compiler/print/index.js
index a3e10085de..4a78854e1e 100644
--- a/packages/svelte/src/compiler/print/index.js
+++ b/packages/svelte/src/compiler/print/index.js
@@ -520,6 +520,10 @@ function css_visitors(comments, js_comments) {
 		},
 
 		TypeSelector(node, context) {
+			if (node.namespace !== undefined) {
+				context.write(node.namespace === '*' ? '*' : escape_identifier(node.namespace));
+				context.write('|');
+			}
 			context.write(node.name === '*' ? node.name : escape_identifier(node.name));
 		}
 	};
diff --git a/packages/svelte/src/compiler/types/css.d.ts b/packages/svelte/src/compiler/types/css.d.ts
index b0a763b6a1..96b2bc3a7d 100644
--- a/packages/svelte/src/compiler/types/css.d.ts
+++ b/packages/svelte/src/compiler/types/css.d.ts
@@ -121,6 +121,7 @@ export namespace _CSS {
 	export interface TypeSelector extends BaseNode {
 		type: 'TypeSelector';
 		name: string;
+		namespace?: string;
 	}
 
 	export interface IdSelector extends BaseNode {
diff --git a/packages/svelte/tests/css/samples/namespaced-type-selector/expected.css b/packages/svelte/tests/css/samples/namespaced-type-selector/expected.css
new file mode 100644
index 0000000000..7672a34dcf
--- /dev/null
+++ b/packages/svelte/tests/css/samples/namespaced-type-selector/expected.css
@@ -0,0 +1,17 @@
+	@namespace svg url(http://www.w3.org/2000/svg);
+
+	svg|circle.svelte-xyz {
+		fill: red;
+	}
+
+	*|circle.svelte-xyz {
+		stroke: blue;
+	}
+
+	svg|*.svelte-xyz {
+		color: green;
+	}
+
+	*|*.svelte-xyz {
+		opacity: 0.5;
+	}
diff --git a/packages/svelte/tests/css/samples/namespaced-type-selector/input.svelte b/packages/svelte/tests/css/samples/namespaced-type-selector/input.svelte
new file mode 100644
index 0000000000..17586eab6f
--- /dev/null
+++ b/packages/svelte/tests/css/samples/namespaced-type-selector/input.svelte
@@ -0,0 +1,21 @@
+<svg><circle /></svg>
+
+<style>
+	@namespace svg url(http://www.w3.org/2000/svg);
+
+	svg|circle {
+		fill: red;
+	}
+
+	*|circle {
+		stroke: blue;
+	}
+
+	svg|* {
+		color: green;
+	}
+
+	*|* {
+		opacity: 0.5;
+	}
+</style>
diff --git a/packages/svelte/tests/print/samples/css-namespaced-type-selector/input.svelte b/packages/svelte/tests/print/samples/css-namespaced-type-selector/input.svelte
new file mode 100644
index 0000000000..5e170ceb2a
--- /dev/null
+++ b/packages/svelte/tests/print/samples/css-namespaced-type-selector/input.svelte
@@ -0,0 +1,10 @@
+<style>
+	@namespace svg url(http://www.w3.org/2000/svg);
+
+	svg|circle,
+	*|circle,
+	svg|*,
+	*|* {
+		fill: red;
+	}
+</style>
diff --git a/packages/svelte/tests/print/samples/css-namespaced-type-selector/output.svelte b/packages/svelte/tests/print/samples/css-namespaced-type-selector/output.svelte
new file mode 100644
index 0000000000..3723659b14
--- /dev/null
+++ b/packages/svelte/tests/print/samples/css-namespaced-type-selector/output.svelte
@@ -0,0 +1,12 @@
+
+
+<style>
+	@namespace svg url(http://www.w3.org/2000/svg);
+
+	svg|circle,
+	*|circle,
+	svg|*,
+	*|* {
+		fill: red;
+	}
+</style>
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index b89f61959f..aab3f4c0b4 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -1774,6 +1774,7 @@ declare module 'svelte/compiler' {
 		export interface TypeSelector extends BaseNode {
 			type: 'TypeSelector';
 			name: string;
+			namespace?: string;
 		}
 
 		export interface IdSelector extends BaseNode {

From ee1249b43cb702d1ea97274ba7849fb8153bd4e2 Mon Sep 17 00:00:00 2001
From: Nathan Asdarjian <nathanasdarjian@gmail.com>
Date: Thu, 20 Aug 2026 03:02:07 -0700
Subject: [PATCH 136/222] fix: preserve renderer type in copy() during SSR
 (#18616)

Fixes #18404

`<svelte:head>` combined with two or more components that each use `bind:` on a child component's prop corrupts a renderer's `.type` during SSR, misplacing the head hydration marker in `<body>` instead of `<head>`.

Reason: `copy()` (`packages/svelte/src/internal/server/renderer.js`) rebuilds via `new Renderer(this.global, this.#parent)`. That constructor defaults `.type` from the *parent's* current type, not from `this.type`. To fix it we therefore reassign it (like already do for the boundary elsewhere)
---
 .changeset/hydration-head-renderer-type.md           |  5 +++++
 packages/svelte/src/internal/server/renderer.js      |  1 +
 .../head-with-multiple-binding-components/Foo.svelte |  3 +++
 .../Wrapper.svelte                                   |  6 ++++++
 .../_expected.html                                   |  0
 .../_expected_head.html                              |  4 ++++
 .../main.svelte                                      | 12 ++++++++++++
 7 files changed, 31 insertions(+)
 create mode 100644 .changeset/hydration-head-renderer-type.md
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/Foo.svelte
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/Wrapper.svelte
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/_expected.html
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/_expected_head.html
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/main.svelte

diff --git a/.changeset/hydration-head-renderer-type.md b/.changeset/hydration-head-renderer-type.md
new file mode 100644
index 0000000000..bc566c158d
--- /dev/null
+++ b/.changeset/hydration-head-renderer-type.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: don't corrupt renderer type during SSR's legacy `bind:` retry loop
diff --git a/packages/svelte/src/internal/server/renderer.js b/packages/svelte/src/internal/server/renderer.js
index 35aac64721..ba6a361a90 100644
--- a/packages/svelte/src/internal/server/renderer.js
+++ b/packages/svelte/src/internal/server/renderer.js
@@ -451,6 +451,7 @@ export class Renderer {
 	 */
 	copy() {
 		const copy = new Renderer(this.global, this.#parent);
+		copy.type = this.type;
 		copy.#out = this.#out.map((item) => (item instanceof Renderer ? item.copy() : item));
 		copy.promise = this.promise;
 		return copy;
diff --git a/packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/Foo.svelte b/packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/Foo.svelte
new file mode 100644
index 0000000000..b991cdf968
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/Foo.svelte
@@ -0,0 +1,3 @@
+<script>
+	let { bar = $bindable() } = $props();
+</script>
diff --git a/packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/Wrapper.svelte b/packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/Wrapper.svelte
new file mode 100644
index 0000000000..d48c90fe59
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/Wrapper.svelte
@@ -0,0 +1,6 @@
+<script>
+	import Foo from './Foo.svelte';
+	let bar = $state();
+</script>
+
+<Foo bind:bar />
diff --git a/packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/_expected.html b/packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/_expected.html
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/_expected_head.html b/packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/_expected_head.html
new file mode 100644
index 0000000000..904fa1d9eb
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/_expected_head.html
@@ -0,0 +1,4 @@
+<!--ssr:0-->
+<link rel="canonical" href="/test">
+<meta name="description" content="test">
+<!--ssr:0-->
\ No newline at end of file
diff --git a/packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/main.svelte b/packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/main.svelte
new file mode 100644
index 0000000000..b68ccd07fe
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/head-with-multiple-binding-components/main.svelte
@@ -0,0 +1,12 @@
+<script>
+	import Wrapper from './Wrapper.svelte';
+</script>
+
+<svelte:head>
+	<link rel="canonical" href="/test" />
+	<meta name="description" content="test" />
+</svelte:head>
+
+<Wrapper />
+<Wrapper />
+<Wrapper />

From a4c60ccdbb4b68469444af216bdf5f565ddc2916 Mon Sep 17 00:00:00 2001
From: Sander Machado <sander.machado@barco.com>
Date: Thu, 20 Aug 2026 14:48:02 +0200
Subject: [PATCH 137/222] fix: append_styles resolving to `document.head` in WC
 (#18614)

Fixes #18288

Check the surrounding branch effect's start node to retrieve the correct root node instead of just the anchor, since the latter could come from each.js/branch.js and be a text node that is never going to get connected

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/free-signs-ask.md                  |  5 ++++
 .../svelte/src/internal/client/dom/css.js     |  7 +++++-
 .../deferred-nested-styles/Child.svelte       |  7 ++++++
 .../deferred-nested-styles/_config.js         | 24 +++++++++++++++++++
 .../deferred-nested-styles/main.svelte        | 18 ++++++++++++++
 5 files changed, 60 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/free-signs-ask.md
 create mode 100644 packages/svelte/tests/runtime-browser/custom-elements-samples/deferred-nested-styles/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-browser/custom-elements-samples/deferred-nested-styles/_config.js
 create mode 100644 packages/svelte/tests/runtime-browser/custom-elements-samples/deferred-nested-styles/main.svelte

diff --git a/.changeset/free-signs-ask.md b/.changeset/free-signs-ask.md
new file mode 100644
index 0000000000..7e6c925526
--- /dev/null
+++ b/.changeset/free-signs-ask.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: reliably resolve append_style to its correct root
diff --git a/packages/svelte/src/internal/client/dom/css.js b/packages/svelte/src/internal/client/dom/css.js
index 74bf2d49f9..23f4eff4f7 100644
--- a/packages/svelte/src/internal/client/dom/css.js
+++ b/packages/svelte/src/internal/client/dom/css.js
@@ -2,14 +2,19 @@ import { DEV } from 'esm-env';
 import { register_style } from '../dev/css.js';
 import { effect } from '../reactivity/effects.js';
 import { create_element } from './operations.js';
+import { active_effect } from '../runtime.js';
 
 /**
  * @param {Node} anchor
  * @param {{ hash: string, code: string }} css
  */
 export function append_styles(anchor, css) {
-	// Use `queue_micro_task` to ensure `anchor` is in the DOM, otherwise getRootNode() will yield wrong results
+	// Use an effect to ensure `anchor` is in the DOM, otherwise getRootNode() will yield wrong results
 	effect(() => {
+		// Bit of a hack: branches.js/each.js use offscreen fragments with temporary text nodes that will
+		// never be connected to the real dom. Therfore walk up to the branch that has created the component
+		// whose styles we want to append, and check its node instead. It will be connected by the time we get here.
+		anchor = active_effect?.parent?.nodes?.start ?? anchor;
 		var root = anchor.getRootNode();
 
 		var target = /** @type {ShadowRoot} */ (root).host
diff --git a/packages/svelte/tests/runtime-browser/custom-elements-samples/deferred-nested-styles/Child.svelte b/packages/svelte/tests/runtime-browser/custom-elements-samples/deferred-nested-styles/Child.svelte
new file mode 100644
index 0000000000..86064ab3b1
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/custom-elements-samples/deferred-nested-styles/Child.svelte
@@ -0,0 +1,7 @@
+<p>child</p>
+
+<style>
+	p {
+		color: rgb(255, 0, 0);
+	}
+</style>
diff --git a/packages/svelte/tests/runtime-browser/custom-elements-samples/deferred-nested-styles/_config.js b/packages/svelte/tests/runtime-browser/custom-elements-samples/deferred-nested-styles/_config.js
new file mode 100644
index 0000000000..739921ebf5
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/custom-elements-samples/deferred-nested-styles/_config.js
@@ -0,0 +1,24 @@
+import { assert_ok, test } from '../../assert';
+
+const tick = () => Promise.resolve();
+
+export default test({
+	async test({ assert, target }) {
+		target.innerHTML = '<my-app></my-app>';
+
+		// wait for the initial mount, the `onMount` reveal and the deferred re-render
+		await tick();
+		await tick();
+		await tick();
+		await tick();
+
+		/** @type {any} */
+		const el = target.querySelector('my-app');
+		const p = el.shadowRoot.querySelector('p');
+		assert_ok(p);
+
+		// The child's scoped styles must be injected into the shadow root, not `document.head`
+		assert_ok(el.shadowRoot.querySelector('style'));
+		assert.equal(getComputedStyle(p).color, 'rgb(255, 0, 0)');
+	}
+});
diff --git a/packages/svelte/tests/runtime-browser/custom-elements-samples/deferred-nested-styles/main.svelte b/packages/svelte/tests/runtime-browser/custom-elements-samples/deferred-nested-styles/main.svelte
new file mode 100644
index 0000000000..2bd0456fc1
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/custom-elements-samples/deferred-nested-styles/main.svelte
@@ -0,0 +1,18 @@
+<svelte:options customElement="my-app" />
+
+<script>
+	import { onMount } from 'svelte';
+	import Child from './Child.svelte';
+
+	let items = $state([]);
+
+	// Add the item _after_ the initial mount, so that the each block renders the
+	// new item into an offscreen anchor that is discarded once it's committed to
+	// the DOM. This reproduces styles being injected into `document.head` instead
+	// of the shadow root (https://github.com/sveltejs/svelte/issues/18288)
+	onMount(() => {
+		items = [1];
+	});
+</script>
+
+{#each items as item (item)}<Child />{/each}

From a166761b041922978b35126f60a7b4092fcc1148 Mon Sep 17 00:00:00 2001
From: Magnar Ovedal Myrtveit <magnar@myrtveit.com>
Date: Thu, 20 Aug 2026 15:15:27 +0200
Subject: [PATCH 138/222] fix: treat concise arrow function bodies as implicit
 returns when calculating blockers (#18613)

Fixes #18612.

A concise arrow body does not contain a `ReturnStatement` which we traverse in full calculate_blockers (else we bail on functions), so short-cut to `touch` there.


---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/light-pandas-attack.md                 |  5 +++++
 .../svelte/src/compiler/phases/2-analyze/index.js | 15 +++++++++------
 .../async-bind-factory-function-remote/_config.js |  4 ++--
 .../main.svelte                                   |  5 +++++
 4 files changed, 21 insertions(+), 8 deletions(-)
 create mode 100644 .changeset/light-pandas-attack.md

diff --git a/.changeset/light-pandas-attack.md b/.changeset/light-pandas-attack.md
new file mode 100644
index 0000000000..e6eface376
--- /dev/null
+++ b/.changeset/light-pandas-attack.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: treat concise arrow function bodies as implicit returns when calculating blockers
diff --git a/packages/svelte/src/compiler/phases/2-analyze/index.js b/packages/svelte/src/compiler/phases/2-analyze/index.js
index 67e9030188..d81053a08d 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/index.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/index.js
@@ -1235,12 +1235,15 @@ function calculate_blockers(instance, analysis) {
 				? /** @type {ESTree.FunctionExpression | ESTree.ArrowFunctionExpression} */ (fn.init)
 				: fn;
 
-		trace_references(
-			init.body,
-			reads_writes,
-			reads_writes,
-			/** @type {Scope} */ (instance.scopes.get(init))
-		);
+		const fn_scope = /** @type {Scope} */ (instance.scopes.get(init));
+
+		if (init.body.type === 'BlockStatement') {
+			trace_references(init.body, reads_writes, reads_writes, fn_scope);
+		} else {
+			// A concise arrow body is an implicit return, so treat it like the
+			// `ReturnStatement` visitor in `trace_references` would.
+			touch(init.body, fn_scope, reads_writes);
+		}
 
 		const max = [...reads_writes].reduce((max, binding) => {
 			if (binding.blocker) {
diff --git a/packages/svelte/tests/runtime-runes/samples/async-bind-factory-function-remote/_config.js b/packages/svelte/tests/runtime-runes/samples/async-bind-factory-function-remote/_config.js
index 080e2d278c..60e58b27a1 100644
--- a/packages/svelte/tests/runtime-runes/samples/async-bind-factory-function-remote/_config.js
+++ b/packages/svelte/tests/runtime-runes/samples/async-bind-factory-function-remote/_config.js
@@ -3,12 +3,12 @@ import { test } from '../../test';
 
 export default test({
 	mode: ['async-server', 'client', 'hydrate'],
-	ssrHtml: 'true true true true true',
+	ssrHtml: 'true true true true true true',
 
 	async test({ assert, target }) {
 		await new Promise((resolve) => setTimeout(resolve, 10));
 		await tick();
 
-		assert.htmlEqual(target.innerHTML, 'true true true true true');
+		assert.htmlEqual(target.innerHTML, 'true true true true true true');
 	}
 });
diff --git a/packages/svelte/tests/runtime-runes/samples/async-bind-factory-function-remote/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-bind-factory-function-remote/main.svelte
index 5f79a14830..4f8f2f97b8 100644
--- a/packages/svelte/tests/runtime-runes/samples/async-bind-factory-function-remote/main.svelte
+++ b/packages/svelte/tests/runtime-runes/samples/async-bind-factory-function-remote/main.svelte
@@ -21,6 +21,8 @@
 		const indirect = () => checkedFactory()();
 		return indirect;
 	}
+
+	const arrow = () => () => checked;
 </script>
 
 <!-- force into separate effects -->
@@ -39,3 +41,6 @@
 {#if true}
 	{indirectChecked2()()}
 {/if}
+{#if true}
+	{arrow()()}
+{/if}

From 24130c18e210dac351710fcdeb878235d2449bd9 Mon Sep 17 00:00:00 2001
From: kdelay <90545043+kdelay@users.noreply.github.com>
Date: Thu, 20 Aug 2026 22:16:47 +0900
Subject: [PATCH 139/222] fix: parse nth-child `of` syntax without whitespace
 after `of` (#18611)

Fixes #18609

A `<an+b> of <selector>` CSS statement does not need whitespace after `of` if it's followed by a CSS-known syntax (like a `.` which marks a class identifier). Adjust the regex accordingly.
---
 .changeset/chilled-lions-parse.md             |   5 +
 .../src/compiler/phases/1-parse/read/style.js |   5 +-
 .../samples/css-nth-of-minified/input.svelte  |  28 +
 .../samples/css-nth-of-minified/output.json   | 799 ++++++++++++++++++
 4 files changed, 836 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/chilled-lions-parse.md
 create mode 100644 packages/svelte/tests/parser-modern/samples/css-nth-of-minified/input.svelte
 create mode 100644 packages/svelte/tests/parser-modern/samples/css-nth-of-minified/output.json

diff --git a/.changeset/chilled-lions-parse.md b/.changeset/chilled-lions-parse.md
new file mode 100644
index 0000000000..1f2e4a0937
--- /dev/null
+++ b/.changeset/chilled-lions-parse.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: parse `:nth-child(2n of.foo)` where `of` is not followed by whitespace
diff --git a/packages/svelte/src/compiler/phases/1-parse/read/style.js b/packages/svelte/src/compiler/phases/1-parse/read/style.js
index a07d7f6fea..df036d0d33 100644
--- a/packages/svelte/src/compiler/phases/1-parse/read/style.js
+++ b/packages/svelte/src/compiler/phases/1-parse/read/style.js
@@ -7,8 +7,11 @@ const REGEX_CLOSING_BRACKET = /[\s\]]/;
 const REGEX_ATTRIBUTE_FLAGS = /[a-zA-Z]+/y; // only `i` and `s` are valid today, but make it future-proof
 const REGEX_COMBINATOR = /(\+|~|>|\|\|)/y;
 const REGEX_PERCENTAGE = /\d+(\.\d+)?%/y;
+// `of` must be preceded by whitespace, otherwise it would be part of the `<an+b>` token
+// (`2nof` is a single dimension token). It does not need to be followed by whitespace,
+// because a `.`, `#`, `[`, `*`, `:` or `&` already ends the `of` identifier — minifiers rely on that
 const REGEX_NTH_OF =
-	/(even|odd|\+?(\d+|\d*n(\s*[+-]\s*\d+)?)|-\d*n(\s*\+\s*\d+))((?=\s*[,)])|\s+of\s+)/y;
+	/(even|odd|\+?(\d+|\d*n(\s*[+-]\s*\d+)?)|-\d*n(\s*\+\s*\d+))((?=\s*[,)])|\s+of(\s+|(?=[.#[*:&])))/y;
 const REGEX_WHITESPACE_OR_COLON = /[\s:]/;
 const REGEX_LEADING_HYPHEN_OR_DIGIT = /-?\d/y;
 const REGEX_VALID_IDENTIFIER_CHAR = /[a-zA-Z0-9_-]/;
diff --git a/packages/svelte/tests/parser-modern/samples/css-nth-of-minified/input.svelte b/packages/svelte/tests/parser-modern/samples/css-nth-of-minified/input.svelte
new file mode 100644
index 0000000000..3aeda2abc7
--- /dev/null
+++ b/packages/svelte/tests/parser-modern/samples/css-nth-of-minified/input.svelte
@@ -0,0 +1,28 @@
+<style>
+	/* minifiers drop the whitespace after `of`, since the following token ends the identifier */
+	li:nth-child(2n of.important) {
+		background: red;
+	}
+	li:nth-child(even of#first) {
+		background: red;
+	}
+	li:nth-last-child(-n+3 of[data-active]) {
+		background: red;
+	}
+	li:nth-child(2n of*) {
+		background: red;
+	}
+	li:nth-child(2n of:not(.excluded)) {
+		background: red;
+	}
+	li:nth-child(2n of.a, .b) {
+		background: red;
+	}
+	ul {
+		& li:nth-child(2n of&.important) {
+			background: red;
+		}
+	}
+</style>
+
+<li>Foo</li>
diff --git a/packages/svelte/tests/parser-modern/samples/css-nth-of-minified/output.json b/packages/svelte/tests/parser-modern/samples/css-nth-of-minified/output.json
new file mode 100644
index 0000000000..04de9a5e0a
--- /dev/null
+++ b/packages/svelte/tests/parser-modern/samples/css-nth-of-minified/output.json
@@ -0,0 +1,799 @@
+{
+	"css": {
+		"type": "StyleSheet",
+		"start": 0,
+		"end": 511,
+		"attributes": [],
+		"children": [
+			{
+				"type": "Rule",
+				"prelude": {
+					"type": "SelectorList",
+					"start": 104,
+					"end": 133,
+					"children": [
+						{
+							"type": "ComplexSelector",
+							"start": 104,
+							"end": 133,
+							"children": [
+								{
+									"type": "RelativeSelector",
+									"combinator": null,
+									"selectors": [
+										{
+											"type": "TypeSelector",
+											"name": "li",
+											"start": 104,
+											"end": 106
+										},
+										{
+											"type": "PseudoClassSelector",
+											"name": "nth-child",
+											"args": {
+												"type": "SelectorList",
+												"start": 117,
+												"end": 132,
+												"children": [
+													{
+														"type": "ComplexSelector",
+														"start": 117,
+														"end": 132,
+														"children": [
+															{
+																"type": "RelativeSelector",
+																"combinator": null,
+																"selectors": [
+																	{
+																		"type": "Nth",
+																		"value": "2n of",
+																		"start": 117,
+																		"end": 122
+																	},
+																	{
+																		"type": "ClassSelector",
+																		"name": "important",
+																		"start": 122,
+																		"end": 132
+																	}
+																],
+																"start": 117,
+																"end": 132
+															}
+														]
+													}
+												]
+											},
+											"start": 106,
+											"end": 133
+										}
+									],
+									"start": 104,
+									"end": 133
+								}
+							]
+						}
+					]
+				},
+				"block": {
+					"type": "Block",
+					"start": 134,
+					"end": 157,
+					"children": [
+						{
+							"type": "Declaration",
+							"start": 138,
+							"end": 153,
+							"property": "background",
+							"value": "red"
+						}
+					]
+				},
+				"start": 104,
+				"end": 157
+			},
+			{
+				"type": "Rule",
+				"prelude": {
+					"type": "SelectorList",
+					"start": 159,
+					"end": 186,
+					"children": [
+						{
+							"type": "ComplexSelector",
+							"start": 159,
+							"end": 186,
+							"children": [
+								{
+									"type": "RelativeSelector",
+									"combinator": null,
+									"selectors": [
+										{
+											"type": "TypeSelector",
+											"name": "li",
+											"start": 159,
+											"end": 161
+										},
+										{
+											"type": "PseudoClassSelector",
+											"name": "nth-child",
+											"args": {
+												"type": "SelectorList",
+												"start": 172,
+												"end": 185,
+												"children": [
+													{
+														"type": "ComplexSelector",
+														"start": 172,
+														"end": 185,
+														"children": [
+															{
+																"type": "RelativeSelector",
+																"combinator": null,
+																"selectors": [
+																	{
+																		"type": "Nth",
+																		"value": "even of",
+																		"start": 172,
+																		"end": 179
+																	},
+																	{
+																		"type": "IdSelector",
+																		"name": "first",
+																		"start": 179,
+																		"end": 185
+																	}
+																],
+																"start": 172,
+																"end": 185
+															}
+														]
+													}
+												]
+											},
+											"start": 161,
+											"end": 186
+										}
+									],
+									"start": 159,
+									"end": 186
+								}
+							]
+						}
+					]
+				},
+				"block": {
+					"type": "Block",
+					"start": 187,
+					"end": 210,
+					"children": [
+						{
+							"type": "Declaration",
+							"start": 191,
+							"end": 206,
+							"property": "background",
+							"value": "red"
+						}
+					]
+				},
+				"start": 159,
+				"end": 210
+			},
+			{
+				"type": "Rule",
+				"prelude": {
+					"type": "SelectorList",
+					"start": 212,
+					"end": 251,
+					"children": [
+						{
+							"type": "ComplexSelector",
+							"start": 212,
+							"end": 251,
+							"children": [
+								{
+									"type": "RelativeSelector",
+									"combinator": null,
+									"selectors": [
+										{
+											"type": "TypeSelector",
+											"name": "li",
+											"start": 212,
+											"end": 214
+										},
+										{
+											"type": "PseudoClassSelector",
+											"name": "nth-last-child",
+											"args": {
+												"type": "SelectorList",
+												"start": 230,
+												"end": 250,
+												"children": [
+													{
+														"type": "ComplexSelector",
+														"start": 230,
+														"end": 250,
+														"children": [
+															{
+																"type": "RelativeSelector",
+																"combinator": null,
+																"selectors": [
+																	{
+																		"type": "Nth",
+																		"value": "-n+3 of",
+																		"start": 230,
+																		"end": 237
+																	},
+																	{
+																		"type": "AttributeSelector",
+																		"start": 237,
+																		"end": 250,
+																		"name": "data-active",
+																		"matcher": null,
+																		"value": null,
+																		"flags": null
+																	}
+																],
+																"start": 230,
+																"end": 250
+															}
+														]
+													}
+												]
+											},
+											"start": 214,
+											"end": 251
+										}
+									],
+									"start": 212,
+									"end": 251
+								}
+							]
+						}
+					]
+				},
+				"block": {
+					"type": "Block",
+					"start": 252,
+					"end": 275,
+					"children": [
+						{
+							"type": "Declaration",
+							"start": 256,
+							"end": 271,
+							"property": "background",
+							"value": "red"
+						}
+					]
+				},
+				"start": 212,
+				"end": 275
+			},
+			{
+				"type": "Rule",
+				"prelude": {
+					"type": "SelectorList",
+					"start": 277,
+					"end": 297,
+					"children": [
+						{
+							"type": "ComplexSelector",
+							"start": 277,
+							"end": 297,
+							"children": [
+								{
+									"type": "RelativeSelector",
+									"combinator": null,
+									"selectors": [
+										{
+											"type": "TypeSelector",
+											"name": "li",
+											"start": 277,
+											"end": 279
+										},
+										{
+											"type": "PseudoClassSelector",
+											"name": "nth-child",
+											"args": {
+												"type": "SelectorList",
+												"start": 290,
+												"end": 296,
+												"children": [
+													{
+														"type": "ComplexSelector",
+														"start": 290,
+														"end": 296,
+														"children": [
+															{
+																"type": "RelativeSelector",
+																"combinator": null,
+																"selectors": [
+																	{
+																		"type": "Nth",
+																		"value": "2n of",
+																		"start": 290,
+																		"end": 295
+																	},
+																	{
+																		"type": "TypeSelector",
+																		"name": "*",
+																		"start": 295,
+																		"end": 296
+																	}
+																],
+																"start": 290,
+																"end": 296
+															}
+														]
+													}
+												]
+											},
+											"start": 279,
+											"end": 297
+										}
+									],
+									"start": 277,
+									"end": 297
+								}
+							]
+						}
+					]
+				},
+				"block": {
+					"type": "Block",
+					"start": 298,
+					"end": 321,
+					"children": [
+						{
+							"type": "Declaration",
+							"start": 302,
+							"end": 317,
+							"property": "background",
+							"value": "red"
+						}
+					]
+				},
+				"start": 277,
+				"end": 321
+			},
+			{
+				"type": "Rule",
+				"prelude": {
+					"type": "SelectorList",
+					"start": 323,
+					"end": 357,
+					"children": [
+						{
+							"type": "ComplexSelector",
+							"start": 323,
+							"end": 357,
+							"children": [
+								{
+									"type": "RelativeSelector",
+									"combinator": null,
+									"selectors": [
+										{
+											"type": "TypeSelector",
+											"name": "li",
+											"start": 323,
+											"end": 325
+										},
+										{
+											"type": "PseudoClassSelector",
+											"name": "nth-child",
+											"args": {
+												"type": "SelectorList",
+												"start": 336,
+												"end": 356,
+												"children": [
+													{
+														"type": "ComplexSelector",
+														"start": 336,
+														"end": 356,
+														"children": [
+															{
+																"type": "RelativeSelector",
+																"combinator": null,
+																"selectors": [
+																	{
+																		"type": "Nth",
+																		"value": "2n of",
+																		"start": 336,
+																		"end": 341
+																	},
+																	{
+																		"type": "PseudoClassSelector",
+																		"name": "not",
+																		"args": {
+																			"type": "SelectorList",
+																			"start": 346,
+																			"end": 355,
+																			"children": [
+																				{
+																					"type": "ComplexSelector",
+																					"start": 346,
+																					"end": 355,
+																					"children": [
+																						{
+																							"type": "RelativeSelector",
+																							"combinator": null,
+																							"selectors": [
+																								{
+																									"type": "ClassSelector",
+																									"name": "excluded",
+																									"start": 346,
+																									"end": 355
+																								}
+																							],
+																							"start": 346,
+																							"end": 355
+																						}
+																					]
+																				}
+																			]
+																		},
+																		"start": 341,
+																		"end": 356
+																	}
+																],
+																"start": 336,
+																"end": 356
+															}
+														]
+													}
+												]
+											},
+											"start": 325,
+											"end": 357
+										}
+									],
+									"start": 323,
+									"end": 357
+								}
+							]
+						}
+					]
+				},
+				"block": {
+					"type": "Block",
+					"start": 358,
+					"end": 381,
+					"children": [
+						{
+							"type": "Declaration",
+							"start": 362,
+							"end": 377,
+							"property": "background",
+							"value": "red"
+						}
+					]
+				},
+				"start": 323,
+				"end": 381
+			},
+			{
+				"type": "Rule",
+				"prelude": {
+					"type": "SelectorList",
+					"start": 383,
+					"end": 408,
+					"children": [
+						{
+							"type": "ComplexSelector",
+							"start": 383,
+							"end": 408,
+							"children": [
+								{
+									"type": "RelativeSelector",
+									"combinator": null,
+									"selectors": [
+										{
+											"type": "TypeSelector",
+											"name": "li",
+											"start": 383,
+											"end": 385
+										},
+										{
+											"type": "PseudoClassSelector",
+											"name": "nth-child",
+											"args": {
+												"type": "SelectorList",
+												"start": 396,
+												"end": 407,
+												"children": [
+													{
+														"type": "ComplexSelector",
+														"start": 396,
+														"end": 403,
+														"children": [
+															{
+																"type": "RelativeSelector",
+																"combinator": null,
+																"selectors": [
+																	{
+																		"type": "Nth",
+																		"value": "2n of",
+																		"start": 396,
+																		"end": 401
+																	},
+																	{
+																		"type": "ClassSelector",
+																		"name": "a",
+																		"start": 401,
+																		"end": 403
+																	}
+																],
+																"start": 396,
+																"end": 403
+															}
+														]
+													},
+													{
+														"type": "ComplexSelector",
+														"start": 405,
+														"end": 407,
+														"children": [
+															{
+																"type": "RelativeSelector",
+																"combinator": null,
+																"selectors": [
+																	{
+																		"type": "ClassSelector",
+																		"name": "b",
+																		"start": 405,
+																		"end": 407
+																	}
+																],
+																"start": 405,
+																"end": 407
+															}
+														]
+													}
+												]
+											},
+											"start": 385,
+											"end": 408
+										}
+									],
+									"start": 383,
+									"end": 408
+								}
+							]
+						}
+					]
+				},
+				"block": {
+					"type": "Block",
+					"start": 409,
+					"end": 432,
+					"children": [
+						{
+							"type": "Declaration",
+							"start": 413,
+							"end": 428,
+							"property": "background",
+							"value": "red"
+						}
+					]
+				},
+				"start": 383,
+				"end": 432
+			},
+			{
+				"type": "Rule",
+				"prelude": {
+					"type": "SelectorList",
+					"start": 434,
+					"end": 436,
+					"children": [
+						{
+							"type": "ComplexSelector",
+							"start": 434,
+							"end": 436,
+							"children": [
+								{
+									"type": "RelativeSelector",
+									"combinator": null,
+									"selectors": [
+										{
+											"type": "TypeSelector",
+											"name": "ul",
+											"start": 434,
+											"end": 436
+										}
+									],
+									"start": 434,
+									"end": 436
+								}
+							]
+						}
+					]
+				},
+				"block": {
+					"type": "Block",
+					"start": 437,
+					"end": 502,
+					"children": [
+						{
+							"type": "Rule",
+							"prelude": {
+								"type": "SelectorList",
+								"start": 441,
+								"end": 473,
+								"children": [
+									{
+										"type": "ComplexSelector",
+										"start": 441,
+										"end": 473,
+										"children": [
+											{
+												"type": "RelativeSelector",
+												"combinator": null,
+												"selectors": [
+													{
+														"type": "NestingSelector",
+														"name": "&",
+														"start": 441,
+														"end": 442
+													}
+												],
+												"start": 441,
+												"end": 442
+											},
+											{
+												"type": "RelativeSelector",
+												"combinator": {
+													"type": "Combinator",
+													"name": " ",
+													"start": 442,
+													"end": 443
+												},
+												"selectors": [
+													{
+														"type": "TypeSelector",
+														"name": "li",
+														"start": 443,
+														"end": 445
+													},
+													{
+														"type": "PseudoClassSelector",
+														"name": "nth-child",
+														"args": {
+															"type": "SelectorList",
+															"start": 456,
+															"end": 472,
+															"children": [
+																{
+																	"type": "ComplexSelector",
+																	"start": 456,
+																	"end": 472,
+																	"children": [
+																		{
+																			"type": "RelativeSelector",
+																			"combinator": null,
+																			"selectors": [
+																				{
+																					"type": "Nth",
+																					"value": "2n of",
+																					"start": 456,
+																					"end": 461
+																				},
+																				{
+																					"type": "NestingSelector",
+																					"name": "&",
+																					"start": 461,
+																					"end": 462
+																				},
+																				{
+																					"type": "ClassSelector",
+																					"name": "important",
+																					"start": 462,
+																					"end": 472
+																				}
+																			],
+																			"start": 456,
+																			"end": 472
+																		}
+																	]
+																}
+															]
+														},
+														"start": 445,
+														"end": 473
+													}
+												],
+												"start": 442,
+												"end": 473
+											}
+										]
+									}
+								]
+							},
+							"block": {
+								"type": "Block",
+								"start": 474,
+								"end": 499,
+								"children": [
+									{
+										"type": "Declaration",
+										"start": 479,
+										"end": 494,
+										"property": "background",
+										"value": "red"
+									}
+								]
+							},
+							"start": 441,
+							"end": 499
+						}
+					]
+				},
+				"start": 434,
+				"end": 502
+			}
+		],
+		"comments": [
+			{
+				"type": "CSSComment",
+				"value": " minifiers drop the whitespace after `of`, since the following token ends the identifier ",
+				"start": 9,
+				"end": 102
+			}
+		],
+		"content": {
+			"start": 7,
+			"end": 503,
+			"styles": "\n\t/* minifiers drop the whitespace after `of`, since the following token ends the identifier */\n\tli:nth-child(2n of.important) {\n\t\tbackground: red;\n\t}\n\tli:nth-child(even of#first) {\n\t\tbackground: red;\n\t}\n\tli:nth-last-child(-n+3 of[data-active]) {\n\t\tbackground: red;\n\t}\n\tli:nth-child(2n of*) {\n\t\tbackground: red;\n\t}\n\tli:nth-child(2n of:not(.excluded)) {\n\t\tbackground: red;\n\t}\n\tli:nth-child(2n of.a, .b) {\n\t\tbackground: red;\n\t}\n\tul {\n\t\t& li:nth-child(2n of&.important) {\n\t\t\tbackground: red;\n\t\t}\n\t}\n",
+			"comment": null
+		}
+	},
+	"js": [],
+	"start": 0,
+	"end": 525,
+	"type": "Root",
+	"fragment": {
+		"type": "Fragment",
+		"nodes": [
+			{
+				"type": "Text",
+				"start": 511,
+				"end": 513,
+				"raw": "\n\n",
+				"data": "\n\n"
+			},
+			{
+				"type": "RegularElement",
+				"start": 513,
+				"end": 525,
+				"name": "li",
+				"name_loc": {
+					"start": {
+						"line": 28,
+						"column": 1,
+						"character": 514
+					},
+					"end": {
+						"line": 28,
+						"column": 3,
+						"character": 516
+					}
+				},
+				"attributes": [],
+				"fragment": {
+					"type": "Fragment",
+					"nodes": [
+						{
+							"type": "Text",
+							"start": 517,
+							"end": 520,
+							"raw": "Foo",
+							"data": "Foo"
+						}
+					]
+				}
+			}
+		]
+	},
+	"options": null,
+	"comments": []
+}

From 388840b1b29d9f02aebc649f705f4a01ca1c4b51 Mon Sep 17 00:00:00 2001
From: Rudevin <101231071+Rudevin17@users.noreply.github.com>
Date: Thu, 20 Aug 2026 21:23:11 +0800
Subject: [PATCH 140/222] docs: note that transitions bypass CSS
 prefers-reduced-motion (#18597)

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 documentation/docs/03-template-syntax/14-transition.md | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/documentation/docs/03-template-syntax/14-transition.md b/documentation/docs/03-template-syntax/14-transition.md
index 9b14b7b25b..5f722259b5 100644
--- a/documentation/docs/03-template-syntax/14-transition.md
+++ b/documentation/docs/03-template-syntax/14-transition.md
@@ -53,6 +53,12 @@ Transitions can have parameters.
 {/if}
 ```
 
+## Accessibility
+
+Transitions are driven by the [Web Animations API](https://developer.mozilla.org/en-US/docs/Web/API/Web_Animations_API) rather than by CSS. A global `@media (prefers-reduced-motion: reduce)` rule that zeroes `transition-duration` and `animation-duration` therefore has no effect on them.
+
+Use [`prefersReducedMotion`](svelte-motion#prefersReducedMotion) to adjust (or completely disable) the transition accordingly for devices who request reduced motion.
+
 ## Custom transition functions
 
 ```js

From 3feb34a9922bf64610d009d44b0865a7ae88c2ef Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Thu, 20 Aug 2026 09:26:06 -0400
Subject: [PATCH 141/222] chore: deduplicate client/server context helpers
 (#18580)

The server copy of `createContext` shipped without the `missing_context`
throw and #17580 had to hand-mirror the client body back in, so this
duplication has already cost a bug. This moves the realm-independent
parts, the `createContext` tuple, `get_parent_context`, and
`get_or_init_context_map`, into `internal/shared/context.js`, and each
realm keeps its public context functions as thin wrappers over its own
state.
---
 .changeset/shared-context-helpers.md          |  5 ++
 .../svelte/src/internal/client/context.js     | 52 +++---------------
 .../svelte/src/internal/server/context.js     | 55 +++----------------
 .../svelte/src/internal/shared/context.js     | 52 ++++++++++++++++++
 4 files changed, 73 insertions(+), 91 deletions(-)
 create mode 100644 .changeset/shared-context-helpers.md
 create mode 100644 packages/svelte/src/internal/shared/context.js

diff --git a/.changeset/shared-context-helpers.md b/.changeset/shared-context-helpers.md
new file mode 100644
index 0000000000..ecdfcb9a0e
--- /dev/null
+++ b/.changeset/shared-context-helpers.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+chore: deduplicate client and server context helpers
diff --git a/packages/svelte/src/internal/client/context.js b/packages/svelte/src/internal/client/context.js
index 0baef5c63e..f4890d0409 100644
--- a/packages/svelte/src/internal/client/context.js
+++ b/packages/svelte/src/internal/client/context.js
@@ -6,6 +6,7 @@ import { create_user_effect } from './reactivity/effects.js';
 import { async_mode_flag, legacy_mode_flag } from '../flags/index.js';
 import { FILENAME } from '../../constants.js';
 import { BRANCH_EFFECT } from './constants.js';
+import { create_context, get_or_init_context_map } from '../shared/context.js';
 
 /** @type {ComponentContext | null} */
 export let component_context = null;
@@ -79,18 +80,9 @@ export function set_dev_current_component_function(fn) {
  * @since 5.40.0
  */
 export function createContext() {
-	const key = {};
-
-	return [
-		() => {
-			if (!hasContext(key)) {
-				e.missing_context();
-			}
-
-			return getContext(key);
-		},
-		(context) => setContext(key, context)
-	];
+	return /** @type {[() => T, (context: T) => T]} */ (
+		create_context(getContext, setContext, hasContext)
+	);
 }
 
 /**
@@ -104,7 +96,7 @@ export function createContext() {
  * @returns {T}
  */
 export function getContext(key) {
-	const context_map = get_or_init_context_map('getContext');
+	const context_map = get_or_init_context_map(component_context, 'getContext');
 	const result = /** @type {T} */ (context_map.get(key));
 	return result;
 }
@@ -124,7 +116,7 @@ export function getContext(key) {
  * @returns {T}
  */
 export function setContext(key, context) {
-	const context_map = get_or_init_context_map('setContext');
+	const context_map = get_or_init_context_map(component_context, 'setContext');
 
 	if (async_mode_flag) {
 		var flags = /** @type {Effect} */ (active_effect).f;
@@ -151,7 +143,7 @@ export function setContext(key, context) {
  * @returns {boolean}
  */
 export function hasContext(key) {
-	const context_map = get_or_init_context_map('hasContext');
+	const context_map = get_or_init_context_map(component_context, 'hasContext');
 	return context_map.has(key);
 }
 
@@ -164,7 +156,7 @@ export function hasContext(key) {
  * @returns {T}
  */
 export function getAllContexts() {
-	const context_map = get_or_init_context_map('getAllContexts');
+	const context_map = get_or_init_context_map(component_context, 'getAllContexts');
 	return /** @type {T} */ (context_map);
 }
 
@@ -229,31 +221,3 @@ export function pop(component) {
 export function is_runes() {
 	return !legacy_mode_flag || (component_context !== null && component_context.l === null);
 }
-
-/**
- * @param {string} name
- * @returns {Map<unknown, unknown>}
- */
-function get_or_init_context_map(name) {
-	if (component_context === null) {
-		e.lifecycle_outside_component(name);
-	}
-
-	return (component_context.c ??= new Map(get_parent_context(component_context) || undefined));
-}
-
-/**
- * @param {ComponentContext} component_context
- * @returns {Map<unknown, unknown> | null}
- */
-function get_parent_context(component_context) {
-	let parent = component_context.p;
-	while (parent !== null) {
-		const context_map = parent.c;
-		if (context_map !== null) {
-			return context_map;
-		}
-		parent = parent.p;
-	}
-	return null;
-}
diff --git a/packages/svelte/src/internal/server/context.js b/packages/svelte/src/internal/server/context.js
index 6a7dc1f883..de11c11282 100644
--- a/packages/svelte/src/internal/server/context.js
+++ b/packages/svelte/src/internal/server/context.js
@@ -1,6 +1,6 @@
 /** @import { SSRContext } from '#server' */
 import { DEV } from 'esm-env';
-import * as e from './errors.js';
+import { create_context, get_or_init_context_map } from '../shared/context.js';
 
 /** @type {SSRContext | null} */
 export var ssr_context = null;
@@ -16,18 +16,9 @@ export function set_ssr_context(v) {
  * @since 5.40.0
  */
 export function createContext() {
-	const key = {};
-
-	return [
-		() => {
-			if (!hasContext(key)) {
-				e.missing_context();
-			}
-
-			return getContext(key);
-		},
-		(context) => setContext(key, context)
-	];
+	return /** @type {[() => T, (context: T) => T]} */ (
+		create_context(getContext, setContext, hasContext)
+	);
 }
 
 /**
@@ -36,7 +27,7 @@ export function createContext() {
  * @returns {T}
  */
 export function getContext(key) {
-	const context_map = get_or_init_context_map('getContext');
+	const context_map = get_or_init_context_map(ssr_context, 'getContext');
 	const result = /** @type {T} */ (context_map.get(key));
 
 	return result;
@@ -49,7 +40,7 @@ export function getContext(key) {
  * @returns {T}
  */
 export function setContext(key, context) {
-	get_or_init_context_map('setContext').set(key, context);
+	get_or_init_context_map(ssr_context, 'setContext').set(key, context);
 	return context;
 }
 
@@ -58,24 +49,12 @@ export function setContext(key, context) {
  * @returns {boolean}
  */
 export function hasContext(key) {
-	return get_or_init_context_map('hasContext').has(key);
+	return get_or_init_context_map(ssr_context, 'hasContext').has(key);
 }
 
 /** @returns {Map<any, any>} */
 export function getAllContexts() {
-	return get_or_init_context_map('getAllContexts');
-}
-
-/**
- * @param {string} name
- * @returns {Map<unknown, unknown>}
- */
-function get_or_init_context_map(name) {
-	if (ssr_context === null) {
-		e.lifecycle_outside_component(name);
-	}
-
-	return (ssr_context.c ??= new Map(get_parent_context(ssr_context) || undefined));
+	return get_or_init_context_map(ssr_context, 'getAllContexts');
 }
 
 /**
@@ -94,24 +73,6 @@ export function pop() {
 	ssr_context = /** @type {SSRContext} */ (ssr_context).p;
 }
 
-/**
- * @param {SSRContext} ssr_context
- * @returns {Map<unknown, unknown> | null}
- */
-function get_parent_context(ssr_context) {
-	let parent = ssr_context.p;
-
-	while (parent !== null) {
-		const context_map = parent.c;
-		if (context_map !== null) {
-			return context_map;
-		}
-		parent = parent.p;
-	}
-
-	return null;
-}
-
 /**
  * Wraps an `await` expression in such a way that the component context that was
  * active before the expression evaluated can be reapplied afterwards —
diff --git a/packages/svelte/src/internal/shared/context.js b/packages/svelte/src/internal/shared/context.js
new file mode 100644
index 0000000000..943e15e415
--- /dev/null
+++ b/packages/svelte/src/internal/shared/context.js
@@ -0,0 +1,52 @@
+import { lifecycle_outside_component, missing_context } from './errors.js';
+
+/**
+ * @template T
+ * @param {(key: object) => T} get_context
+ * @param {(key: object, context: T) => T} set_context
+ * @param {(key: object) => boolean} has_context
+ * @returns {[() => T, (context: T) => T]}
+ */
+export function create_context(get_context, set_context, has_context) {
+	const key = {};
+
+	return [
+		() => {
+			if (!has_context(key)) {
+				missing_context();
+			}
+
+			return get_context(key);
+		},
+		(context) => set_context(key, context)
+	];
+}
+
+/**
+ * @typedef {{ p: Context | null, c: Map<unknown, unknown> | null }} Context
+ */
+
+/**
+ * @param {Context} context
+ * @returns {Map<unknown, unknown> | null}
+ */
+function get_parent_context(context) {
+	let parent = context.p;
+	while (parent !== null && parent.c === null) {
+		parent = parent.p;
+	}
+	return parent?.c ?? null;
+}
+
+/**
+ * @param {Context | null} context
+ * @param {string} name
+ * @returns {Map<unknown, unknown>}
+ */
+export function get_or_init_context_map(context, name) {
+	if (context === null) {
+		lifecycle_outside_component(name);
+	}
+
+	return (context.c ??= new Map(get_parent_context(context) || undefined));
+}

From 2f684fefd79f6c9ac7975cc18410ba95319a34d6 Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Thu, 20 Aug 2026 09:45:42 -0400
Subject: [PATCH 142/222] docs: clarify that context lookup includes the
 current component and all ancestors (#18581)

Fixes #7916. Context lookup starts at the current component, not the
closest parent. `setContext` followed by `getContext` with the same key
in the same component returns the value.
---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/context-docs-wording.md            |  5 +++++
 .../98-reference/.generated/shared-errors.md  |  4 ++--
 .../svelte/messages/shared-errors/errors.md   |  4 ++--
 .../svelte/src/internal/client/context.js     | 21 +++++++++++--------
 packages/svelte/src/internal/shared/errors.js |  4 ++--
 packages/svelte/types/index.d.ts              | 21 +++++++++++--------
 6 files changed, 35 insertions(+), 24 deletions(-)
 create mode 100644 .changeset/context-docs-wording.md

diff --git a/.changeset/context-docs-wording.md b/.changeset/context-docs-wording.md
new file mode 100644
index 0000000000..6ec9d47ed9
--- /dev/null
+++ b/.changeset/context-docs-wording.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+docs: clarify that context lookup includes the current component and all ancestors
diff --git a/documentation/docs/98-reference/.generated/shared-errors.md b/documentation/docs/98-reference/.generated/shared-errors.md
index 739bd58b35..d7596fc068 100644
--- a/documentation/docs/98-reference/.generated/shared-errors.md
+++ b/documentation/docs/98-reference/.generated/shared-errors.md
@@ -75,10 +75,10 @@ Certain lifecycle methods can only be used during component initialisation. To f
 ### missing_context
 
 ```
-Context was not set in a parent component
+Context was not set in the current component or any of its ancestors
 ```
 
-The [`createContext()`](svelte#createContext) utility returns a `[get, set]` pair of functions. `get` will throw an error if `set` was not used to set the context in a parent component.
+The [`createContext()`](svelte#createContext) utility returns a `[get, set]` pair of functions. `get` will throw an error if `set` was not used to set the context in the current component or any of its ancestors.
 
 ### snippet_without_render_tag
 
diff --git a/packages/svelte/messages/shared-errors/errors.md b/packages/svelte/messages/shared-errors/errors.md
index 3ff474768e..43dca57ac8 100644
--- a/packages/svelte/messages/shared-errors/errors.md
+++ b/packages/svelte/messages/shared-errors/errors.md
@@ -62,9 +62,9 @@ Certain lifecycle methods can only be used during component initialisation. To f
 
 ## missing_context
 
-> Context was not set in a parent component
+> Context was not set in the current component or any of its ancestors
 
-The [`createContext()`](svelte#createContext) utility returns a `[get, set]` pair of functions. `get` will throw an error if `set` was not used to set the context in a parent component.
+The [`createContext()`](svelte#createContext) utility returns a `[get, set]` pair of functions. `get` will throw an error if `set` was not used to set the context in the current component or any of its ancestors.
 
 ## snippet_without_render_tag
 
diff --git a/packages/svelte/src/internal/client/context.js b/packages/svelte/src/internal/client/context.js
index f4890d0409..0a7b2cdf31 100644
--- a/packages/svelte/src/internal/client/context.js
+++ b/packages/svelte/src/internal/client/context.js
@@ -73,7 +73,8 @@ export function set_dev_current_component_function(fn) {
 /**
  * Returns a `[get, set]` pair of functions for working with context in a type-safe way.
  *
- * `get` will throw an error if no parent component called `set`.
+ * `get` will throw an error if `set` has not yet been called in the current component or any of
+ * its ancestors.
  *
  * @template T
  * @returns {[() => T, (context: T) => T]}
@@ -86,7 +87,9 @@ export function createContext() {
 }
 
 /**
- * Retrieves the context that belongs to the closest parent component with the specified `key`.
+ * Retrieves the context set with the specified `key` in the current component or any of its
+ * ancestors. If multiple components set the same key, the value from the closest one is returned.
+ * A `setContext` call in the current component is only visible to `getContext` calls that run after it.
  * Must be called during component initialisation.
  *
  * [`createContext`](https://svelte.dev/docs/svelte/svelte#createContext) is a type-safe alternative.
@@ -103,8 +106,8 @@ export function getContext(key) {
 
 /**
  * Associates an arbitrary `context` object with the current component and the specified `key`
- * and returns that object. The context is then available to children of the component
- * (including slotted content) with `getContext`.
+ * and returns that object. The context is then available to the component itself and all of its
+ * descendants (including slotted content) with `getContext`.
  *
  * Like lifecycle functions, this must be called during component initialisation.
  *
@@ -136,8 +139,8 @@ export function setContext(key, context) {
 }
 
 /**
- * Checks whether a given `key` has been set in the context of a parent component.
- * Must be called during component initialisation.
+ * Checks whether a given `key` has been set in the context of the current component or any of
+ * its ancestors. Must be called during component initialisation.
  *
  * @param {any} key
  * @returns {boolean}
@@ -148,9 +151,9 @@ export function hasContext(key) {
 }
 
 /**
- * Retrieves the whole context map that belongs to the closest parent component.
- * Must be called during component initialisation. Useful, for example, if you
- * programmatically create a component and want to pass the existing context to it.
+ * Retrieves the whole context map that belongs to the current component, including entries
+ * inherited from its ancestors. Must be called during component initialisation. Useful, for
+ * example, if you programmatically create a component and want to pass the existing context to it.
  *
  * @template {Map<any, any>} [T=Map<any, any>]
  * @returns {T}
diff --git a/packages/svelte/src/internal/shared/errors.js b/packages/svelte/src/internal/shared/errors.js
index a4ad8cecff..9e41788dc1 100644
--- a/packages/svelte/src/internal/shared/errors.js
+++ b/packages/svelte/src/internal/shared/errors.js
@@ -86,12 +86,12 @@ export function lifecycle_outside_component(name) {
 }
 
 /**
- * Context was not set in a parent component
+ * Context was not set in the current component or any of its ancestors
  * @returns {never}
  */
 export function missing_context() {
 	if (DEV) {
-		const error = new Error(`missing_context\nContext was not set in a parent component\nhttps://svelte.dev/e/missing_context`);
+		const error = new Error(`missing_context\nContext was not set in the current component or any of its ancestors\nhttps://svelte.dev/e/missing_context`);
 
 		error.name = 'Svelte error';
 
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index aab3f4c0b4..b752ef5e07 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -494,13 +494,16 @@ declare module 'svelte' {
 	/**
 	 * Returns a `[get, set]` pair of functions for working with context in a type-safe way.
 	 *
-	 * `get` will throw an error if no parent component called `set`.
+	 * `get` will throw an error if `set` has not yet been called in the current component or any of
+	 * its ancestors.
 	 *
 	 * @since 5.40.0
 	 */
 	export function createContext<T>(): [() => T, (context: T) => T];
 	/**
-	 * Retrieves the context that belongs to the closest parent component with the specified `key`.
+	 * Retrieves the context set with the specified `key` in the current component or any of its
+	 * ancestors. If multiple components set the same key, the value from the closest one is returned.
+	 * A `setContext` call in the current component is only visible to `getContext` calls that run after it.
 	 * Must be called during component initialisation.
 	 *
 	 * [`createContext`](https://svelte.dev/docs/svelte/svelte#createContext) is a type-safe alternative.
@@ -509,8 +512,8 @@ declare module 'svelte' {
 	export function getContext<T>(key: any): T;
 	/**
 	 * Associates an arbitrary `context` object with the current component and the specified `key`
-	 * and returns that object. The context is then available to children of the component
-	 * (including slotted content) with `getContext`.
+	 * and returns that object. The context is then available to the component itself and all of its
+	 * descendants (including slotted content) with `getContext`.
 	 *
 	 * Like lifecycle functions, this must be called during component initialisation.
 	 *
@@ -519,15 +522,15 @@ declare module 'svelte' {
 	 * */
 	export function setContext<T>(key: any, context: T): T;
 	/**
-	 * Checks whether a given `key` has been set in the context of a parent component.
-	 * Must be called during component initialisation.
+	 * Checks whether a given `key` has been set in the context of the current component or any of
+	 * its ancestors. Must be called during component initialisation.
 	 *
 	 * */
 	export function hasContext(key: any): boolean;
 	/**
-	 * Retrieves the whole context map that belongs to the closest parent component.
-	 * Must be called during component initialisation. Useful, for example, if you
-	 * programmatically create a component and want to pass the existing context to it.
+	 * Retrieves the whole context map that belongs to the current component, including entries
+	 * inherited from its ancestors. Must be called during component initialisation. Useful, for
+	 * example, if you programmatically create a component and want to pass the existing context to it.
 	 *
 	 * */
 	export function getAllContexts<T extends Map<any, any> = Map<any, any>>(): T;

From f159e14de767ed333c89d1f42380d80eb2978140 Mon Sep 17 00:00:00 2001
From: "jyc.dev" <jycouet@gmail.com>
Date: Thu, 20 Aug 2026 15:59:35 +0200
Subject: [PATCH 143/222] chore: switch to @changesets/changelog-github
 (#18570)

Switch `@svitejs/changesets-changelog-github-compact` to
`@changesets/changelog-github` (its new `template` option reproduces the
same compact output).
---
 .changeset/config.json |  2 +-
 package.json           |  2 +-
 pnpm-lock.yaml         | 88 +++++++++++++-----------------------------
 3 files changed, 28 insertions(+), 64 deletions(-)

diff --git a/.changeset/config.json b/.changeset/config.json
index b56077a922..785aa01e70 100644
--- a/.changeset/config.json
+++ b/.changeset/config.json
@@ -1,6 +1,6 @@
 {
 	"$schema": "https://unpkg.com/@changesets/config@2.3.0/schema.json",
-	"changelog": ["@svitejs/changesets-changelog-github-compact", { "repo": "sveltejs/svelte" }],
+	"changelog": ["@changesets/changelog-github", { "repo": "sveltejs/svelte", "template": "\n- {summary} {ref}" }],
 	"commit": false,
 	"fixed": [],
 	"linked": [],
diff --git a/package.json b/package.json
index a178d31698..16fc26bc32 100644
--- a/package.json
+++ b/package.json
@@ -26,10 +26,10 @@
     "bench:debug": "NODE_ENV=production node --allow-natives-syntax --inspect-brk ./benchmarking/run.js"
   },
   "devDependencies": {
+    "@changesets/changelog-github": "1.0.0-next.6",
     "@changesets/cli": "^2.29.8",
     "@eslint/js": "^10.0.0",
     "@sveltejs/eslint-config": "^9.0.0",
-    "@svitejs/changesets-changelog-github-compact": "^1.1.0",
     "@types/node": "^20.11.5",
     "@types/picomatch": "^4.0.2",
     "@vitest/coverage-v8": "^4.1.7",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 6331fd0789..095d166118 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -8,6 +8,9 @@ importers:
 
   .:
     devDependencies:
+      '@changesets/changelog-github':
+        specifier: 1.0.0-next.6
+        version: 1.0.0-next.6
       '@changesets/cli':
         specifier: ^2.29.8
         version: 2.29.8(@types/node@20.19.17)
@@ -17,9 +20,6 @@ importers:
       '@sveltejs/eslint-config':
         specifier: ^9.0.0
         version: 9.0.0(@eslint/js@10.0.1(eslint@10.0.0))(@stylistic/eslint-plugin-js@1.8.0(eslint@10.0.0))(eslint-config-prettier@9.1.0(eslint@10.0.0))(eslint-plugin-n@17.24.0(eslint@10.0.0)(typescript@5.5.4))(eslint-plugin-svelte@3.15.0(eslint@10.0.0)(svelte@packages+svelte))(eslint@10.0.0)(typescript-eslint@8.56.0(eslint@10.0.0)(typescript@5.5.4))(typescript@5.5.4)
-      '@svitejs/changesets-changelog-github-compact':
-        specifier: ^1.1.0
-        version: 1.1.0
       '@types/node':
         specifier: ^20.11.5
         version: 20.19.17
@@ -236,6 +236,10 @@ packages:
   '@changesets/changelog-git@0.2.1':
     resolution: {integrity: sha512-x/xEleCFLH28c3bQeQIyeZf8lFXyDFVn1SgcBiR2Tw/r4IAWlk1fzxCEZ6NxQAjF2Nwtczoen3OA2qR+UawQ8Q==}
 
+  '@changesets/changelog-github@1.0.0-next.6':
+    resolution: {integrity: sha512-0ShCWgNt50xP0mryAYT8wtSkMUinG8uhxXgCgwHZ4UvJnR2f4ns8OsGAxYu8FIds7kHFdLOz7qX4YQ6AX4tVUA==}
+    engines: {node: ^22.11 || ^24 || >=26}
+
   '@changesets/cli@2.29.8':
     resolution: {integrity: sha512-1weuGZpP63YWUYjay/E84qqwcnt5yJMM0tep10Up7Q5cS/DGe2IZ0Uj3HNMxGhCINZuR7aO9WBMdKnPit5ZDPA==}
     hasBin: true
@@ -249,8 +253,9 @@ packages:
   '@changesets/get-dependents-graph@2.1.3':
     resolution: {integrity: sha512-gphr+v0mv2I3Oxt19VdWRRUxq3sseyUpX9DaHpTUmLj92Y10AGy+XOtV+kbM6L/fDcpx7/ISDFK6T8A/P3lOdQ==}
 
-  '@changesets/get-github-info@0.5.2':
-    resolution: {integrity: sha512-JppheLu7S114aEs157fOZDjFqUDpm7eHdq5E8SSR0gUBTEK0cNSHsrSR5a66xs0z3RWuo46QvA3vawp8BxDHvg==}
+  '@changesets/get-github-info@1.0.0-next.4':
+    resolution: {integrity: sha512-Bosh+XOoFvLMzAj301tg6phbrEggBtvEccrnceEvYsKSM7PjcIa32Fy22SU5g+501HZywkdwcAlybdWF+e/zzw==}
+    engines: {node: ^22.11 || ^24 || >=26}
 
   '@changesets/get-release-plan@4.0.14':
     resolution: {integrity: sha512-yjZMHpUHgl4Xl5gRlolVuxDkm4HgSJqT93Ri1Uz8kGrQb+5iJ8dkXJ20M2j/Y4iV5QzS2c5SeTxVSKX+2eMI0g==}
@@ -282,6 +287,10 @@ packages:
   '@changesets/types@6.1.0':
     resolution: {integrity: sha512-rKQcJ+o1nKNgeoYRHKOS07tAMNd3YSN0uHaJOZYjBAgxfV7TUE7JE+z4BzZdQwb5hKaYbayKN5KrYV7ODb2rAA==}
 
+  '@changesets/types@7.0.0-next.7':
+    resolution: {integrity: sha512-1XyshLw+lRCg2DWxi1Qt3hbezjBostHzXvGXVgSzAeZ+fL+r2ikcMbpaQ98D9ivwKhYFf1FBbKbEc+XsBZsIJQ==}
+    engines: {node: ^22.11 || ^24 || >=26}
+
   '@changesets/write@0.4.0':
     resolution: {integrity: sha512-CdTLvIOPiCNuH71pyDu3rA+Q0n65cmAbXnwWH84rKGiFumFzkmHNT8KHTMEchcxN+Kl8I54xGUhJ7l3E7X396Q==}
 
@@ -933,11 +942,6 @@ packages:
       svelte: ^5.0.0
       vite: ^6.3.0 || ^7.0.0
 
-  '@svitejs/changesets-changelog-github-compact@1.1.0':
-    resolution: {integrity: sha512-qhUGGDHcpbY2zpjW3SwqchuW8J/5EzlPFud7xNntHKA7f3a/mx5+g+ruJKFHSAiVZYo30PALt+AyhmPUNKH/Og==}
-    engines: {node: ^14.13.1 || ^16.0.0 || >=18}
-    deprecated: unmaintained
-
   '@types/aria-query@5.0.4':
     resolution: {integrity: sha512-rfT93uj5s0PRL7EzccGMs3brplhcrghnDoV26NqKhCAS1hVo+WdNsPvE/yb6ilfr5hi2MEk6d5EWJTKdxg8jVw==}
 
@@ -1229,8 +1233,8 @@ packages:
     resolution: {integrity: sha512-ZYP5VBHshaDAiVZxjbRVcFJpc+4xGgT0bK3vzy1HLN8jTO975HEbuYzZJcHoQEY5K1a0z8YayJkyVETa08eNTg==}
     engines: {node: '>=18'}
 
-  dataloader@1.4.0:
-    resolution: {integrity: sha512-68s5jYdlvasItOJnCuI2Q9s4q98g0pCyL3HrcKJu8KNugUl8ahgmZYg38ysLTgQjjXX3H8CJLkAvWrclWfcalw==}
+  dataloader@2.2.3:
+    resolution: {integrity: sha512-y2krtASINtPFS1rSDjacrFgn1dcUuoREVabwlOGOe4SdxenREqwjwjElAdwvbGM7kgZz9a3KVicWR7vcz8rnzA==}
 
   debug@4.4.3:
     resolution: {integrity: sha512-RGwwWnwQvkVfavKVt22FGLw+xYSdzARwm0ru6DhTVA3umU5hZc28V3kO4stgYryrTlLpuvgI9GiijltAjNbcqA==}
@@ -1283,10 +1287,6 @@ packages:
     resolution: {integrity: sha512-WkrWp9GR4KXfKGYzOLmTuGVi1UWFfws377n9cc55/tb6DuqyF6pcQ5AbiHEshaDpY9v6oaSr2XCDidGmMwdzIA==}
     engines: {node: '>=8'}
 
-  dotenv@16.3.2:
-    resolution: {integrity: sha512-HTlk5nmhkm8F6JcdXvHIzaorzCoziNQT9mGxLPVXW8wJF1TiGSL60ZGB4gHWabHOaMmWmhvk2/lPHfnBiT78AQ==}
-    engines: {node: '>=12'}
-
   dts-buddy@0.5.5:
     resolution: {integrity: sha512-Mu5PJuP7C+EqZIwDtW/bG1tVli1UFhRIyW/dERBVBYk28OviTkribu9S2LpDQ0HF2MbkqnjQIkbbE6HnepdNTQ==}
     hasBin: true
@@ -1853,15 +1853,6 @@ packages:
   natural-compare@1.4.0:
     resolution: {integrity: sha512-OWND8ei3VtNC9h7V60qff3SVobHr996CTwgxubgyQYEpg290h9J0buyECNNJexkFm5sOajh5G116RYA1c8ZMSw==}
 
-  node-fetch@2.7.0:
-    resolution: {integrity: sha512-c4FRfUm/dbcWZ7U+1Wq0AwCyFL+3nt2bEw05wfxSz+DWpWsitgmSgYmy2dQdWyKC1694ELPqMs/YzUSNozLt8A==}
-    engines: {node: 4.x || >=6.0.0}
-    peerDependencies:
-      encoding: ^0.1.0
-    peerDependenciesMeta:
-      encoding:
-        optional: true
-
   normalize-path@3.0.0:
     resolution: {integrity: sha512-6eZs5Ls3WtCisHWp9S2GUy8dqkpGi4BVSz3GaqiE6ezub0512ESztXUwUB6C6IKbQkY2Pnb/mD4WYojCRwcwLA==}
     engines: {node: '>=0.10.0'}
@@ -2237,9 +2228,6 @@ packages:
     resolution: {integrity: sha512-FRKsF7cz96xIIeMZ82ehjC3xW2E+O2+v11udrDYewUbszngYhsGa8z6YUMMzO9QJZzzyd0nGGXnML/TReX6W8Q==}
     engines: {node: '>=16'}
 
-  tr46@0.0.3:
-    resolution: {integrity: sha512-N3WMsuqV66lT30CrXNbEjx4GEwlow3v6rr4mCcv6prnfwhS01rkgyFdjPNBYd9br7LpXV1+Emh01fHnq2Gdgrw==}
-
   tr46@5.0.0:
     resolution: {integrity: sha512-tk2G5R2KRwBd+ZN0zaEXpmzdKyOYksXwywulIX95MBODjSzMIuQnQ3m8JxgbhnL1LeVo7lqQKsYa1O3Htl7K5g==}
     engines: {node: '>=18'}
@@ -2430,9 +2418,6 @@ packages:
   web-features@3.29.0:
     resolution: {integrity: sha512-r8m0Xj77/PSHXEbv2U3UuLhw5gE4U+YAPek5hCor5DMsS9Qnwtxl5FSfam3dXQo7Gl0gxK9BRrcQLlOBZZZXpw==}
 
-  webidl-conversions@3.0.1:
-    resolution: {integrity: sha512-2JAn3z8AR6rjK8Sm8orRC0h/bcl/DqL7tRPdGZ4I1CjdF+EaMLmYxBHyXuKL849eucPFhvBoxMsflfOb8kxaeQ==}
-
   webidl-conversions@7.0.0:
     resolution: {integrity: sha512-VwddBukDzu71offAQR975unBIGqfKZpM+8ZX6ySk8nYhVoo5CYaZyzt3YBvYtRtO+aoGlqxPg/B87NGVZ/fu6g==}
     engines: {node: '>=12'}
@@ -2450,9 +2435,6 @@ packages:
     resolution: {integrity: sha512-1lfMEm2IEr7RIV+f4lUNPOqfFL+pO+Xw3fJSqmjX9AbXcXcYOkCe1P6+9VBZB6n94af16NfZf+sSk0JCBZC9aw==}
     engines: {node: '>=18'}
 
-  whatwg-url@5.0.0:
-    resolution: {integrity: sha512-saE57nupxk6v3HY35+jzBwYa0rKSy0XR8JSxZPwgLr7ys0IBzhGviA1/TUGJLmSVqs8pb9AnvICXEuOHLprYTw==}
-
   which@2.0.2:
     resolution: {integrity: sha512-BLI3Tl1TW3Pvl70l3yq3Y64i+awpwXqsGBYWkkqMtnbXgrMD+yj7rhW0kuEDxzJaYXGjEW5ogapKNMEKNMjibA==}
     engines: {node: '>= 8'}
@@ -2547,6 +2529,11 @@ snapshots:
     dependencies:
       '@changesets/types': 6.1.0
 
+  '@changesets/changelog-github@1.0.0-next.6':
+    dependencies:
+      '@changesets/get-github-info': 1.0.0-next.4
+      '@changesets/types': 7.0.0-next.7
+
   '@changesets/cli@2.29.8(@types/node@20.19.17)':
     dependencies:
       '@changesets/apply-release-plan': 7.0.14
@@ -2601,12 +2588,9 @@ snapshots:
       picocolors: 1.1.1
       semver: 7.7.4
 
-  '@changesets/get-github-info@0.5.2':
+  '@changesets/get-github-info@1.0.0-next.4':
     dependencies:
-      dataloader: 1.4.0
-      node-fetch: 2.7.0
-    transitivePeerDependencies:
-      - encoding
+      dataloader: 2.2.3
 
   '@changesets/get-release-plan@4.0.14':
     dependencies:
@@ -2662,6 +2646,8 @@ snapshots:
 
   '@changesets/types@6.1.0': {}
 
+  '@changesets/types@7.0.0-next.7': {}
+
   '@changesets/write@0.4.0':
     dependencies:
       '@changesets/types': 6.1.0
@@ -3111,13 +3097,6 @@ snapshots:
     transitivePeerDependencies:
       - supports-color
 
-  '@svitejs/changesets-changelog-github-compact@1.1.0':
-    dependencies:
-      '@changesets/get-github-info': 0.5.2
-      dotenv: 16.3.2
-    transitivePeerDependencies:
-      - encoding
-
   '@types/aria-query@5.0.4': {}
 
   '@types/chai@5.2.3':
@@ -3439,7 +3418,7 @@ snapshots:
       whatwg-mimetype: 4.0.0
       whatwg-url: 14.0.0
 
-  dataloader@1.4.0: {}
+  dataloader@2.2.3: {}
 
   debug@4.4.3:
     dependencies:
@@ -3473,8 +3452,6 @@ snapshots:
     dependencies:
       path-type: 4.0.0
 
-  dotenv@16.3.2: {}
-
   dts-buddy@0.5.5(typescript@5.5.4):
     dependencies:
       '@jridgewell/source-map': 0.3.6
@@ -4095,10 +4072,6 @@ snapshots:
 
   natural-compare@1.4.0: {}
 
-  node-fetch@2.7.0:
-    dependencies:
-      whatwg-url: 5.0.0
-
   normalize-path@3.0.0:
     optional: true
 
@@ -4435,8 +4408,6 @@ snapshots:
     dependencies:
       tldts: 6.1.64
 
-  tr46@0.0.3: {}
-
   tr46@5.0.0:
     dependencies:
       punycode: 2.3.1
@@ -4595,8 +4566,6 @@ snapshots:
 
   web-features@3.29.0: {}
 
-  webidl-conversions@3.0.1: {}
-
   webidl-conversions@7.0.0: {}
 
   whatwg-encoding@3.1.1:
@@ -4610,11 +4579,6 @@ snapshots:
       tr46: 5.0.0
       webidl-conversions: 7.0.0
 
-  whatwg-url@5.0.0:
-    dependencies:
-      tr46: 0.0.3
-      webidl-conversions: 3.0.1
-
   which@2.0.2:
     dependencies:
       isexe: 2.0.0

From ffc0e6e7ef5961ec81a9df90cd166e5d06ec33fd Mon Sep 17 00:00:00 2001
From: randalmurphal <49694326+randalmurphal@users.noreply.github.com>
Date: Thu, 20 Aug 2026 10:19:42 -0500
Subject: [PATCH 144/222] fix: release last_propagated_event after event
 propagation settles (#18569)

Fixes #18568

`last_propagated_event` was added in #16527 to stop Firefox from garbage collecting the event wrapper mid-propagation. The problem with this is that the even is now retained until the next event, which could be a while. This removes it after a macrotask.

Co-authored-by: rmurphy <rmurphy@fortressinfosec.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
---
 .changeset/spotty-ducks-refuse.md             |  5 +++++
 .../internal/client/dom/elements/events.js    | 20 ++++++++++++++++++-
 2 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/spotty-ducks-refuse.md

diff --git a/.changeset/spotty-ducks-refuse.md b/.changeset/spotty-ducks-refuse.md
new file mode 100644
index 0000000000..6faba7e89f
--- /dev/null
+++ b/.changeset/spotty-ducks-refuse.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: release `last_propagated_event` after event propagation settles so it no longer retains the last event's target subtree
diff --git a/packages/svelte/src/internal/client/dom/elements/events.js b/packages/svelte/src/internal/client/dom/elements/events.js
index 45e042a8c6..068c64b9ab 100644
--- a/packages/svelte/src/internal/client/dom/elements/events.js
+++ b/packages/svelte/src/internal/client/dom/elements/events.js
@@ -159,12 +159,15 @@ export function delegate(events) {
 }
 
 // used to store the reference to the currently propagated event
-// to prevent garbage collection between microtasks in Firefox
+// to prevent garbage collection between microtasks in Firefox (<= 141)
 // If the event object is GCed too early, the expando __root property
 // set on the event object is lost, causing the event delegation
 // to process the event twice
 let last_propagated_event = null;
 
+// whether a task is already queued to clear `last_propagated_event`
+let last_propagated_event_clear_scheduled = false;
+
 /**
  * @this {EventTarget}
  * @param {Event} event
@@ -179,6 +182,21 @@ export function handle_event_propagation(event) {
 
 	last_propagated_event = event;
 
+	// The reference is only needed while the event can still reach another
+	// delegated root, i.e. during the current (synchronous) dispatch and its
+	// microtask checkpoints. Clearing it in a later task preserves the
+	// Firefox workaround while making sure the slot doesn't retain the last
+	// event forever — through `event.target` it would otherwise keep the
+	// entire detached subtree of whatever the user last clicked in alive
+	// until the next delegated event happens to arrive.
+	if (!last_propagated_event_clear_scheduled) {
+		last_propagated_event_clear_scheduled = true;
+		setTimeout(() => {
+			last_propagated_event_clear_scheduled = false;
+			last_propagated_event = null;
+		});
+	}
+
 	// composedPath contains list of nodes the event has propagated through.
 	// We check `event_symbol` to skip all nodes below it in case this is a
 	// parent of the `event_symbol` node, which indicates that there's nested

From 950e2a837c344fa2d656cb98f471eba9a15ec4a4 Mon Sep 17 00:00:00 2001
From: Mukund Sarma <23266464+dnukumamras@users.noreply.github.com>
Date: Thu, 20 Aug 2026 08:22:27 -0700
Subject: [PATCH 145/222] fix: strip comments from inline style values in
 linear time (#18553)

`to_style()` strips CSS comments from an inline `style` value with
`/\s*\/\*.*?\*\/\s*/g`. The leading `\s*` makes the match retry from
every position, so a long run of whitespace backtracks in O(n^2). When a
dynamic `style={value}` sits on an element that also has a `style:`
directive, that regex runs on `value`, so a large whitespace string can
stall rendering (server) or the main thread (client).

### Fix

Drop the surrounding `\s*` and match only the comment: `/\/\*.*?\*\//g` to prevent quadratic regex.
The surrounding whitespace was already removed by the `.trim()`

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/strip-style-comments.md                | 5 +++++
 packages/svelte/src/internal/shared/attributes.js | 3 ++-
 2 files changed, 7 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/strip-style-comments.md

diff --git a/.changeset/strip-style-comments.md b/.changeset/strip-style-comments.md
new file mode 100644
index 0000000000..6a27e431df
--- /dev/null
+++ b/.changeset/strip-style-comments.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: strip comments from inline `style` values in linear time
diff --git a/packages/svelte/src/internal/shared/attributes.js b/packages/svelte/src/internal/shared/attributes.js
index 487a40baf3..bb1abf22c1 100644
--- a/packages/svelte/src/internal/shared/attributes.js
+++ b/packages/svelte/src/internal/shared/attributes.js
@@ -142,8 +142,9 @@ export function to_style(value, styles) {
 		}
 
 		if (value) {
+			// strip comments; surrounding whitespace is handled by the trims below (which is much faster than doing it through regex)
 			value = String(value)
-				.replaceAll(/\s*\/\*.*?\*\/\s*/g, '')
+				.replaceAll(/\/\*.*?\*\//g, '')
 				.trim();
 
 			/** @type {boolean | '"' | "'"} */

From 545205b4206bb5e7c070c55ae6b0600437291646 Mon Sep 17 00:00:00 2001
From: Joe Schafer <joe@canals.ai>
Date: Thu, 20 Aug 2026 08:41:55 -0700
Subject: [PATCH 146/222] perf: make async blocker analysis linear (#18549)

`trace_references` recreated a fresh seen set for every CallExpression,
so `touch` re-walked the same transitive assignment graph once per call.
For N calls reaching an N-deep binding chain, this was $O(N^2)$.

Share one seen set per trace_references invocation. Use separate sets
for the write-directed CallExpression touches and the read-directed
ReturnStatement touches. The shared set ensures each assignment-value
expression is walked at most once, making the traversal linear. `touch`
only ever adds to a fixed target set, so skipping an already-seen
expression never drops a binding: compiler output is byte-identical.

Complements #18548.

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/tidy-melons-attack.md              |  5 +++++
 .../src/compiler/phases/2-analyze/index.js    | 21 ++++++++++---------
 2 files changed, 16 insertions(+), 10 deletions(-)
 create mode 100644 .changeset/tidy-melons-attack.md

diff --git a/.changeset/tidy-melons-attack.md b/.changeset/tidy-melons-attack.md
new file mode 100644
index 0000000000..87e62a1c4d
--- /dev/null
+++ b/.changeset/tidy-melons-attack.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+perf: make async blocker analysis scale linearly with the number of top-level references
diff --git a/packages/svelte/src/compiler/phases/2-analyze/index.js b/packages/svelte/src/compiler/phases/2-analyze/index.js
index d81053a08d..f9cf2f1d89 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/index.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/index.js
@@ -958,7 +958,7 @@ function calculate_blockers(instance, analysis) {
 	 * @param {Set<Binding>} touched
 	 * @param {Set<ESTree.Node>} seen
 	 */
-	const touch = (expression, scope, touched, seen = new Set()) => {
+	const touch = (expression, scope, touched, seen) => {
 		if (seen.has(expression)) return;
 		seen.add(expression);
 
@@ -1015,6 +1015,13 @@ function calculate_blockers(instance, analysis) {
 			}
 		}
 
+		// Share seen nodes across calls so transitive assignments are only visited once.
+		// Keep separate read/write state because the target sets can differ.
+		/** @type {Set<ESTree.Node>} */
+		const writes_seen = new Set();
+		/** @type {Set<ESTree.Node>} */
+		const reads_seen = new Set();
+
 		walk(
 			node,
 			{ scope },
@@ -1044,13 +1051,7 @@ function calculate_blockers(instance, analysis) {
 					const rune = get_rune(node, context.state.scope);
 					if (rune === '$effect') return;
 
-					/** @type {Set<Binding>} */
-					const touched = new Set();
-					touch(node, context.state.scope, touched);
-
-					for (const b of touched) {
-						writes.add(b);
-					}
+					touch(node, context.state.scope, writes, writes_seen);
 				},
 				Identifier(node, context) {
 					const parent = /** @type {ESTree.Node} */ (context.path.at(-1));
@@ -1066,7 +1067,7 @@ function calculate_blockers(instance, analysis) {
 					// might be called immediately, so we have to touch all references within it. Example:
 					// function foo() { return () => blocker; } foo(); // blocker is touched
 					if (node.argument) {
-						touch(node.argument, context.state.scope, reads);
+						touch(node.argument, context.state.scope, reads, reads_seen);
 					}
 				},
 				// don't look inside functions until they are called
@@ -1242,7 +1243,7 @@ function calculate_blockers(instance, analysis) {
 		} else {
 			// A concise arrow body is an implicit return, so treat it like the
 			// `ReturnStatement` visitor in `trace_references` would.
-			touch(init.body, fn_scope, reads_writes);
+			touch(init.body, fn_scope, reads_writes, new Set());
 		}
 
 		const max = [...reads_writes].reduce((max, binding) => {

From 5ccdfe355739229573b20a2fa2ee49e38e3868fe Mon Sep 17 00:00:00 2001
From: Scott Wu <sw@scottwu.ca>
Date: Fri, 21 Aug 2026 00:05:45 +0800
Subject: [PATCH 147/222] docs: note comments within tags possibility (#18482)

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .../docs/03-template-syntax/01-basic-markup.md        | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/documentation/docs/03-template-syntax/01-basic-markup.md b/documentation/docs/03-template-syntax/01-basic-markup.md
index feecfe033e..436f307f84 100644
--- a/documentation/docs/03-template-syntax/01-basic-markup.md
+++ b/documentation/docs/03-template-syntax/01-basic-markup.md
@@ -215,3 +215,14 @@ You can add a special comment starting with `@component` that will show up when
 	</h1>
 </main>
 ````
+
+You can also put JavaScript-style comments within tags between attributes:
+
+```svelte
+<div
+  // this is a comment!
+  data-foo="bar"
+>
+  foo bar
+</div>
+```

From 56a036f4ce873a24ee6631a06d03d372523d7a9b Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Thu, 20 Aug 2026 15:13:38 -0400
Subject: [PATCH 148/222] Version Packages (#18640)

This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.


# Releases
## svelte@5.56.10

### Patch Changes

- fix: preserve CSS escape sequences when printing selectors
([#18667](https://github.com/sveltejs/svelte/pull/18667))

- fix: parse `:nth-child(2n of.foo)` where `of` is not followed by
whitespace ([#18611](https://github.com/sveltejs/svelte/pull/18611))

- fix: transform expressions inside labeled statements during server
compilation ([#18617](https://github.com/sveltejs/svelte/pull/18617))

- docs: clarify that context lookup includes the current component and
all ancestors ([#18581](https://github.com/sveltejs/svelte/pull/18581))

- fix: apply CSS custom properties with falsy values on components
([#18634](https://github.com/sveltejs/svelte/pull/18634))

- fix: correctly print `{#await ... catch x}` et al
([#18645](https://github.com/sveltejs/svelte/pull/18645))

- fix: ignore comments of Program node during migration script
([#18656](https://github.com/sveltejs/svelte/pull/18656))

- fix: reliably resolve append_style to its correct root
([#18614](https://github.com/sveltejs/svelte/pull/18614))

- fix: clean up removed capture event handlers from spread attributes
([#18618](https://github.com/sveltejs/svelte/pull/18618))

- fix: don't corrupt renderer type during SSR's legacy `bind:` retry
loop ([#18616](https://github.com/sveltejs/svelte/pull/18616))

- fix: treat concise arrow function bodies as implicit returns when
calculating blockers
([#18613](https://github.com/sveltejs/svelte/pull/18613))

- fix: give effect teardowns the value from before the first write in a
flush ([#18620](https://github.com/sveltejs/svelte/pull/18620))

- fix: avoid double-calling a derived reference when destructuring
`$derived` of another `$derived` during server-side rendering
([#18668](https://github.com/sveltejs/svelte/pull/18668))

- fix: preserve namespaces in CSS type selectors
([#18678](https://github.com/sveltejs/svelte/pull/18678))

- fix: increment private state fields through a non-`this` receiver
([#18622](https://github.com/sveltejs/svelte/pull/18622))

- chore: deduplicate client and server context helpers
([#18580](https://github.com/sveltejs/svelte/pull/18580))

- fix: release `last_propagated_event` after event propagation settles
so it no longer retains the last event's target subtree
([#18569](https://github.com/sveltejs/svelte/pull/18569))

- fix: allow custom elements to receive async values as props
([#18661](https://github.com/sveltejs/svelte/pull/18661))

- fix: strip comments from inline `style` values in linear time
([#18553](https://github.com/sveltejs/svelte/pull/18553))

- fix: prevent declaration comments from breaking server derived
references ([#18641](https://github.com/sveltejs/svelte/pull/18641))

- perf: make async blocker analysis scale linearly with the number of
top-level references
([#18549](https://github.com/sveltejs/svelte/pull/18549))

- fix: preserve short-circuiting for logical assignments to private
state fields ([#18594](https://github.com/sveltejs/svelte/pull/18594))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/calm-foxes-reprint.md              |  5 --
 .changeset/chilled-lions-parse.md             |  5 --
 .changeset/clear-badgers-type.md              |  5 --
 .changeset/context-docs-wording.md            |  5 --
 .changeset/css-props-falsy-values.md          |  5 --
 .changeset/eighty-pugs-shave.md               |  5 --
 .changeset/fix-migrate-comment-no-position.md |  5 --
 .changeset/free-signs-ask.md                  |  5 --
 .changeset/happy-spoons-talk.md               |  5 --
 .changeset/hydration-head-renderer-type.md    |  5 --
 .changeset/light-pandas-attack.md             |  5 --
 .changeset/lucky-pears-smoke.md               |  5 --
 .changeset/nervous-dolls-clean.md             |  5 --
 .changeset/pink-chairs-matter.md              |  5 --
 .changeset/quiet-donkeys-clap.md              |  5 --
 .changeset/shared-context-helpers.md          |  5 --
 .changeset/spotty-ducks-refuse.md             |  5 --
 .changeset/spotty-files-trade.md              |  5 --
 .changeset/strip-style-comments.md            |  5 --
 .changeset/tidy-cats-return.md                |  5 --
 .changeset/tidy-melons-attack.md              |  5 --
 .changeset/tidy-ravens-assign.md              |  5 --
 packages/svelte/CHANGELOG.md                  | 48 +++++++++++++++++++
 packages/svelte/package.json                  |  2 +-
 packages/svelte/src/version.js                |  2 +-
 25 files changed, 50 insertions(+), 112 deletions(-)
 delete mode 100644 .changeset/calm-foxes-reprint.md
 delete mode 100644 .changeset/chilled-lions-parse.md
 delete mode 100644 .changeset/clear-badgers-type.md
 delete mode 100644 .changeset/context-docs-wording.md
 delete mode 100644 .changeset/css-props-falsy-values.md
 delete mode 100644 .changeset/eighty-pugs-shave.md
 delete mode 100644 .changeset/fix-migrate-comment-no-position.md
 delete mode 100644 .changeset/free-signs-ask.md
 delete mode 100644 .changeset/happy-spoons-talk.md
 delete mode 100644 .changeset/hydration-head-renderer-type.md
 delete mode 100644 .changeset/light-pandas-attack.md
 delete mode 100644 .changeset/lucky-pears-smoke.md
 delete mode 100644 .changeset/nervous-dolls-clean.md
 delete mode 100644 .changeset/pink-chairs-matter.md
 delete mode 100644 .changeset/quiet-donkeys-clap.md
 delete mode 100644 .changeset/shared-context-helpers.md
 delete mode 100644 .changeset/spotty-ducks-refuse.md
 delete mode 100644 .changeset/spotty-files-trade.md
 delete mode 100644 .changeset/strip-style-comments.md
 delete mode 100644 .changeset/tidy-cats-return.md
 delete mode 100644 .changeset/tidy-melons-attack.md
 delete mode 100644 .changeset/tidy-ravens-assign.md

diff --git a/.changeset/calm-foxes-reprint.md b/.changeset/calm-foxes-reprint.md
deleted file mode 100644
index 08ea964bfe..0000000000
--- a/.changeset/calm-foxes-reprint.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: preserve CSS escape sequences when printing selectors
\ No newline at end of file
diff --git a/.changeset/chilled-lions-parse.md b/.changeset/chilled-lions-parse.md
deleted file mode 100644
index 1f2e4a0937..0000000000
--- a/.changeset/chilled-lions-parse.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: parse `:nth-child(2n of.foo)` where `of` is not followed by whitespace
diff --git a/.changeset/clear-badgers-type.md b/.changeset/clear-badgers-type.md
deleted file mode 100644
index 3668aa7644..0000000000
--- a/.changeset/clear-badgers-type.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: transform expressions inside labeled statements during server compilation
diff --git a/.changeset/context-docs-wording.md b/.changeset/context-docs-wording.md
deleted file mode 100644
index 6ec9d47ed9..0000000000
--- a/.changeset/context-docs-wording.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-docs: clarify that context lookup includes the current component and all ancestors
diff --git a/.changeset/css-props-falsy-values.md b/.changeset/css-props-falsy-values.md
deleted file mode 100644
index 677594ddaf..0000000000
--- a/.changeset/css-props-falsy-values.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: apply CSS custom properties with falsy values on components
diff --git a/.changeset/eighty-pugs-shave.md b/.changeset/eighty-pugs-shave.md
deleted file mode 100644
index 0f0eaf9a6c..0000000000
--- a/.changeset/eighty-pugs-shave.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: correctly print `{#await ... catch x}` et al
diff --git a/.changeset/fix-migrate-comment-no-position.md b/.changeset/fix-migrate-comment-no-position.md
deleted file mode 100644
index fa9981dc60..0000000000
--- a/.changeset/fix-migrate-comment-no-position.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: ignore comments of Program node during migration script
diff --git a/.changeset/free-signs-ask.md b/.changeset/free-signs-ask.md
deleted file mode 100644
index 7e6c925526..0000000000
--- a/.changeset/free-signs-ask.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: reliably resolve append_style to its correct root
diff --git a/.changeset/happy-spoons-talk.md b/.changeset/happy-spoons-talk.md
deleted file mode 100644
index cf165320db..0000000000
--- a/.changeset/happy-spoons-talk.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: clean up removed capture event handlers from spread attributes
diff --git a/.changeset/hydration-head-renderer-type.md b/.changeset/hydration-head-renderer-type.md
deleted file mode 100644
index bc566c158d..0000000000
--- a/.changeset/hydration-head-renderer-type.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: don't corrupt renderer type during SSR's legacy `bind:` retry loop
diff --git a/.changeset/light-pandas-attack.md b/.changeset/light-pandas-attack.md
deleted file mode 100644
index e6eface376..0000000000
--- a/.changeset/light-pandas-attack.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: treat concise arrow function bodies as implicit returns when calculating blockers
diff --git a/.changeset/lucky-pears-smoke.md b/.changeset/lucky-pears-smoke.md
deleted file mode 100644
index 816a37dca5..0000000000
--- a/.changeset/lucky-pears-smoke.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: give effect teardowns the value from before the first write in a flush
diff --git a/.changeset/nervous-dolls-clean.md b/.changeset/nervous-dolls-clean.md
deleted file mode 100644
index 5b31bdd3c7..0000000000
--- a/.changeset/nervous-dolls-clean.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: avoid double-calling a derived reference when destructuring `$derived` of another `$derived` during server-side rendering
diff --git a/.changeset/pink-chairs-matter.md b/.changeset/pink-chairs-matter.md
deleted file mode 100644
index 6a8a6e75f3..0000000000
--- a/.changeset/pink-chairs-matter.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: preserve namespaces in CSS type selectors
diff --git a/.changeset/quiet-donkeys-clap.md b/.changeset/quiet-donkeys-clap.md
deleted file mode 100644
index dc9df3b7e1..0000000000
--- a/.changeset/quiet-donkeys-clap.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: increment private state fields through a non-`this` receiver
diff --git a/.changeset/shared-context-helpers.md b/.changeset/shared-context-helpers.md
deleted file mode 100644
index ecdfcb9a0e..0000000000
--- a/.changeset/shared-context-helpers.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-chore: deduplicate client and server context helpers
diff --git a/.changeset/spotty-ducks-refuse.md b/.changeset/spotty-ducks-refuse.md
deleted file mode 100644
index 6faba7e89f..0000000000
--- a/.changeset/spotty-ducks-refuse.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: release `last_propagated_event` after event propagation settles so it no longer retains the last event's target subtree
diff --git a/.changeset/spotty-files-trade.md b/.changeset/spotty-files-trade.md
deleted file mode 100644
index 39975b7a9a..0000000000
--- a/.changeset/spotty-files-trade.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: allow custom elements to receive async values as props
diff --git a/.changeset/strip-style-comments.md b/.changeset/strip-style-comments.md
deleted file mode 100644
index 6a27e431df..0000000000
--- a/.changeset/strip-style-comments.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: strip comments from inline `style` values in linear time
diff --git a/.changeset/tidy-cats-return.md b/.changeset/tidy-cats-return.md
deleted file mode 100644
index 0c041196ef..0000000000
--- a/.changeset/tidy-cats-return.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: prevent declaration comments from breaking server derived references
diff --git a/.changeset/tidy-melons-attack.md b/.changeset/tidy-melons-attack.md
deleted file mode 100644
index 87e62a1c4d..0000000000
--- a/.changeset/tidy-melons-attack.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-perf: make async blocker analysis scale linearly with the number of top-level references
diff --git a/.changeset/tidy-ravens-assign.md b/.changeset/tidy-ravens-assign.md
deleted file mode 100644
index 312adde9b5..0000000000
--- a/.changeset/tidy-ravens-assign.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: preserve short-circuiting for logical assignments to private state fields
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 5ec2101bf7..e66b3db109 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,53 @@
 # svelte
 
+## 5.56.10
+
+### Patch Changes
+
+- fix: preserve CSS escape sequences when printing selectors ([#18667](https://github.com/sveltejs/svelte/pull/18667))
+
+- fix: parse `:nth-child(2n of.foo)` where `of` is not followed by whitespace ([#18611](https://github.com/sveltejs/svelte/pull/18611))
+
+- fix: transform expressions inside labeled statements during server compilation ([#18617](https://github.com/sveltejs/svelte/pull/18617))
+
+- docs: clarify that context lookup includes the current component and all ancestors ([#18581](https://github.com/sveltejs/svelte/pull/18581))
+
+- fix: apply CSS custom properties with falsy values on components ([#18634](https://github.com/sveltejs/svelte/pull/18634))
+
+- fix: correctly print `{#await ... catch x}` et al ([#18645](https://github.com/sveltejs/svelte/pull/18645))
+
+- fix: ignore comments of Program node during migration script ([#18656](https://github.com/sveltejs/svelte/pull/18656))
+
+- fix: reliably resolve append_style to its correct root ([#18614](https://github.com/sveltejs/svelte/pull/18614))
+
+- fix: clean up removed capture event handlers from spread attributes ([#18618](https://github.com/sveltejs/svelte/pull/18618))
+
+- fix: don't corrupt renderer type during SSR's legacy `bind:` retry loop ([#18616](https://github.com/sveltejs/svelte/pull/18616))
+
+- fix: treat concise arrow function bodies as implicit returns when calculating blockers ([#18613](https://github.com/sveltejs/svelte/pull/18613))
+
+- fix: give effect teardowns the value from before the first write in a flush ([#18620](https://github.com/sveltejs/svelte/pull/18620))
+
+- fix: avoid double-calling a derived reference when destructuring `$derived` of another `$derived` during server-side rendering ([#18668](https://github.com/sveltejs/svelte/pull/18668))
+
+- fix: preserve namespaces in CSS type selectors ([#18678](https://github.com/sveltejs/svelte/pull/18678))
+
+- fix: increment private state fields through a non-`this` receiver ([#18622](https://github.com/sveltejs/svelte/pull/18622))
+
+- chore: deduplicate client and server context helpers ([#18580](https://github.com/sveltejs/svelte/pull/18580))
+
+- fix: release `last_propagated_event` after event propagation settles so it no longer retains the last event's target subtree ([#18569](https://github.com/sveltejs/svelte/pull/18569))
+
+- fix: allow custom elements to receive async values as props ([#18661](https://github.com/sveltejs/svelte/pull/18661))
+
+- fix: strip comments from inline `style` values in linear time ([#18553](https://github.com/sveltejs/svelte/pull/18553))
+
+- fix: prevent declaration comments from breaking server derived references ([#18641](https://github.com/sveltejs/svelte/pull/18641))
+
+- perf: make async blocker analysis scale linearly with the number of top-level references ([#18549](https://github.com/sveltejs/svelte/pull/18549))
+
+- fix: preserve short-circuiting for logical assignments to private state fields ([#18594](https://github.com/sveltejs/svelte/pull/18594))
+
 ## 5.56.9
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 0bd1580969..2da4ee428d 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.56.9",
+  "version": "5.56.10",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index e3b4c740f0..b9f1637abb 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.56.9';
+export const VERSION = '5.56.10';
 export const PUBLIC_VERSION = '5';

From a7ba9e85aa47583f84a19a622667bc4c97514c2f Mon Sep 17 00:00:00 2001
From: Ben McCann <322311+benmccann@users.noreply.github.com>
Date: Thu, 20 Aug 2026 13:34:02 -0700
Subject: [PATCH 149/222] docs: update mobile FAQ (#18665)

Updated to mention Symbiote Native

---------

Co-authored-by: vercel[bot] <35613825+vercel[bot]@users.noreply.github.com>
---
 documentation/docs/07-misc/99-faq.md | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/documentation/docs/07-misc/99-faq.md b/documentation/docs/07-misc/99-faq.md
index 035629e5ae..a9067b0703 100644
--- a/documentation/docs/07-misc/99-faq.md
+++ b/documentation/docs/07-misc/99-faq.md
@@ -99,7 +99,9 @@ However, you can use any router library. A sampling of available routers are hig
 
 While most mobile apps are written without using JavaScript, if you'd like to leverage your existing Svelte components and knowledge of Svelte when building mobile apps, you can turn a [SvelteKit SPA](https://kit.svelte.dev/docs/single-page-apps) into a mobile app with [Tauri](https://v2.tauri.app/start/frontend/sveltekit/) or [Capacitor](https://capacitorjs.com/solution/svelte). Mobile features like the camera, geolocation, and push notifications are available via plugins for both platforms.
 
-Some work has been completed towards [custom renderer support in Svelte 5](https://github.com/sveltejs/svelte/issues/15470), but this feature is not yet available. The custom rendering API would support additional mobile frameworks like Lynx JS and Svelte Native. Svelte Native was an option available for Svelte 4, but Svelte 5 does not currently support it. Svelte Native lets you write NativeScript apps using Svelte components that contain [NativeScript UI components](https://docs.nativescript.org/ui/) rather than DOM elements, which may be familiar for users coming from React Native.
+You can also write apps in Svelte that compiles to native components by using [Symbiote Native](https://docs.symbiote-native.dev/), which leverages the infrastructure provided by React Native.
+
+Work has been completed towards [custom renderer support in Svelte 5](https://github.com/sveltejs/svelte/issues/15470), but this feature is not yet merged. The custom rendering API will allow support in additional mobile frameworks like Lynx JS and Svelte Native. Symbiote Native will also adopt this API. Svelte Native was an option available for Svelte 4, but Svelte 5 does not currently support it. Svelte Native lets you write NativeScript apps using Svelte components that contain [NativeScript UI components](https://docs.nativescript.org/ui/) rather than DOM elements.
 
 ## Can I tell Svelte not to remove my unused styles?
 

From faf1e103c53675cbe71860f331d4fedd84c8d612 Mon Sep 17 00:00:00 2001
From: Siddhesh Kabra <146343711+Xsidz@users.noreply.github.com>
Date: Fri, 21 Aug 2026 02:20:44 +0530
Subject: [PATCH 150/222] fix: prevent onoutroend from firing twice when
 compilerOptions.hmr is true (#18655)

Fixes #18440

`hmr()` in `packages/svelte/src/internal/client/dev/hmr.js` wrapped a
component in a `block` effect containing a `branch` effect. It forwarded
the inner effect's `nodes` object to the outer block:

This shared the same reference, meaning `outer_block.nodes ===
inner_branch.nodes`. When `pause_children` collected transitions for
unmounting, Each collected transition had `out(check)` called multiple times,
starting multiple animations and firing `outroend` multiple times.

Fix by only copying `start`/`end` (the DOM range info the outer block needs)
without sharing the transitions array:
---
 .changeset/fix-hmr-onoutroend-double-fire.md  |  5 +++++
 .../svelte/src/internal/client/dev/hmr.js     | 19 +++++++++++++++----
 2 files changed, 20 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/fix-hmr-onoutroend-double-fire.md

diff --git a/.changeset/fix-hmr-onoutroend-double-fire.md b/.changeset/fix-hmr-onoutroend-double-fire.md
new file mode 100644
index 0000000000..0eafbfa731
--- /dev/null
+++ b/.changeset/fix-hmr-onoutroend-double-fire.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: prevent onoutroend from firing twice when compilerOptions.hmr is true
diff --git a/packages/svelte/src/internal/client/dev/hmr.js b/packages/svelte/src/internal/client/dev/hmr.js
index 73dba95f9b..0e988fe66d 100644
--- a/packages/svelte/src/internal/client/dev/hmr.js
+++ b/packages/svelte/src/internal/client/dev/hmr.js
@@ -57,10 +57,21 @@ export function hmr(fn) {
 				if (ran) set_should_intro(true);
 			});
 
-			// Forward the nodes from the inner effect to the outer active effect which would
-			// get them if the HMR wrapper wasn't there. Do this inside the block not outside
-			// so that HMR updates to the component will also update the nodes on the active effect.
-			/** @type {Effect} */ (active_effect).nodes = effect.nodes;
+			// Forward the start/end DOM nodes from the inner effect to the outer active effect
+			// which would get them if the HMR wrapper wasn't there. Do this inside the block not
+			// outside so that HMR updates to the component will also update the nodes on the
+			// active effect. We copy only start/end, not the full nodes object, so that
+			// pause_children does not collect transitions from both effects and fire outroend twice.
+			var inner_nodes = effect.nodes;
+			if (inner_nodes) {
+				var ae = /** @type {Effect} */ (active_effect);
+				if (ae.nodes) {
+					ae.nodes.start = inner_nodes.start;
+					ae.nodes.end = inner_nodes.end;
+				} else {
+					ae.nodes = { start: inner_nodes.start, end: inner_nodes.end, a: null, t: null };
+				}
+			}
 		}, EFFECT_TRANSPARENT);
 
 		ran = true;

From cac27c783ed0c12011fa223825b6877dc6760825 Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Thu, 20 Aug 2026 16:51:54 -0400
Subject: [PATCH 151/222] feat: export RenderOutput, SyncRenderOutput, Csp and
 Sha256Source from svelte/server (#18648)

`render` returns `RenderOutput` and takes `csp: Csp`, but both are
declared in `src/internal/server/types.d.ts` and never exported. The
generated `svelte/server` block has them without `export`, so nothing
outside the repo can import them and the docs page names `RenderOutput`
as the return type with nothing on the page defining it.

Moves them into `src/server/public.d.ts` the way `svelte/motion` went in
#17967, rather than re-exporting internals.
---
 .changeset/olive-jars-repeat.md                |  5 +++++
 packages/svelte/src/internal/server/index.js   |  2 +-
 .../svelte/src/internal/server/renderer.js     |  3 ++-
 packages/svelte/src/internal/server/types.d.ts | 18 ------------------
 packages/svelte/src/legacy/legacy-server.js    |  2 +-
 packages/svelte/src/server/index.d.ts          |  4 +++-
 packages/svelte/src/server/public.d.ts         | 17 +++++++++++++++++
 .../svelte/tests/server-side-rendering/test.ts |  3 +--
 packages/svelte/types/index.d.ts               |  8 ++++----
 9 files changed, 34 insertions(+), 28 deletions(-)
 create mode 100644 .changeset/olive-jars-repeat.md
 create mode 100644 packages/svelte/src/server/public.d.ts

diff --git a/.changeset/olive-jars-repeat.md b/.changeset/olive-jars-repeat.md
new file mode 100644
index 0000000000..815b5adf71
--- /dev/null
+++ b/.changeset/olive-jars-repeat.md
@@ -0,0 +1,5 @@
+---
+'svelte': minor
+---
+
+feat: export `RenderOutput`, `SyncRenderOutput`, `Csp` and `Sha256Source` from `svelte/server`
diff --git a/packages/svelte/src/internal/server/index.js b/packages/svelte/src/internal/server/index.js
index 12f76f188e..3d8ec5fe5e 100644
--- a/packages/svelte/src/internal/server/index.js
+++ b/packages/svelte/src/internal/server/index.js
@@ -1,5 +1,5 @@
 /** @import { ComponentType, SvelteComponent, Component } from 'svelte' */
-/** @import { Csp, RenderOutput } from '#server' */
+/** @import { Csp, RenderOutput } from '../../server/public.js' */
 /** @import { Store } from '#shared' */
 export { FILENAME, HMR } from '../../constants.js';
 import { attr, clsx, to_class, to_style } from '../shared/attributes.js';
diff --git a/packages/svelte/src/internal/server/renderer.js b/packages/svelte/src/internal/server/renderer.js
index ba6a361a90..5fb0bb86d5 100644
--- a/packages/svelte/src/internal/server/renderer.js
+++ b/packages/svelte/src/internal/server/renderer.js
@@ -1,5 +1,6 @@
 /** @import { Component } from 'svelte' */
-/** @import { Csp, HydratableContext, RenderOutput, SSRContext, SyncRenderOutput, Sha256Source } from './types.js' */
+/** @import { HydratableContext, SSRContext } from './types.js' */
+/** @import { Csp, RenderOutput, SyncRenderOutput, Sha256Source } from '../../server/public.js' */
 /** @import { MaybePromise } from '#shared' */
 import { async_mode_flag } from '../flags/index.js';
 import { abort } from './abort-signal.js';
diff --git a/packages/svelte/src/internal/server/types.d.ts b/packages/svelte/src/internal/server/types.d.ts
index ea6282c176..899255d366 100644
--- a/packages/svelte/src/internal/server/types.d.ts
+++ b/packages/svelte/src/internal/server/types.d.ts
@@ -15,8 +15,6 @@ export interface SSRContext {
 	element?: Element;
 }
 
-export type Csp = { nonce?: string; hash?: boolean };
-
 export interface HydratableLookupEntry {
 	value: unknown;
 	serialized: string;
@@ -34,19 +32,3 @@ export interface HydratableContext {
 export interface RenderContext {
 	hydratable: HydratableContext;
 }
-
-export type Sha256Source = `sha256-${string}`;
-
-export interface SyncRenderOutput {
-	/** HTML that goes into the `<head>` */
-	head: string;
-	/** @deprecated use `body` instead */
-	html: string;
-	/** HTML that goes somewhere into the `<body>` */
-	body: string;
-	hashes: {
-		script: Sha256Source[];
-	};
-}
-
-export type RenderOutput = SyncRenderOutput & PromiseLike<SyncRenderOutput>;
diff --git a/packages/svelte/src/legacy/legacy-server.js b/packages/svelte/src/legacy/legacy-server.js
index 2c43aab6ac..913f2dccb2 100644
--- a/packages/svelte/src/legacy/legacy-server.js
+++ b/packages/svelte/src/legacy/legacy-server.js
@@ -1,5 +1,5 @@
 /** @import { SvelteComponent } from '../index.js' */
-/** @import { Csp } from '#server' */
+/** @import { Csp } from '../server/public.js' */
 import { asClassComponent as as_class_component, createClassComponent } from './legacy-client.js';
 import { render } from '../internal/server/index.js';
 import { async_mode_flag } from '../internal/flags/index.js';
diff --git a/packages/svelte/src/server/index.d.ts b/packages/svelte/src/server/index.d.ts
index db75afb9ed..7297c57490 100644
--- a/packages/svelte/src/server/index.d.ts
+++ b/packages/svelte/src/server/index.d.ts
@@ -1,6 +1,8 @@
-import type { Csp, RenderOutput } from '#server';
+import type { Csp, RenderOutput } from './public.js';
 import type { ComponentProps, Component, SvelteComponent, ComponentType } from 'svelte';
 
+export type { Csp, RenderOutput, SyncRenderOutput, Sha256Source } from './public.js';
+
 /**
  * Only available on the server and when compiling with the `server` option.
  * Takes a component and returns an object with `body` and `head` properties on it, which you can use to populate the HTML when server-rendering your app.
diff --git a/packages/svelte/src/server/public.d.ts b/packages/svelte/src/server/public.d.ts
new file mode 100644
index 0000000000..8ef98aef9c
--- /dev/null
+++ b/packages/svelte/src/server/public.d.ts
@@ -0,0 +1,17 @@
+export type Csp = { nonce?: string; hash?: boolean };
+
+export type Sha256Source = `sha256-${string}`;
+
+export interface SyncRenderOutput {
+	/** HTML that goes into the `<head>` */
+	head: string;
+	/** @deprecated use `body` instead */
+	html: string;
+	/** HTML that goes somewhere into the `<body>` */
+	body: string;
+	hashes: {
+		script: Sha256Source[];
+	};
+}
+
+export type RenderOutput = SyncRenderOutput & PromiseLike<SyncRenderOutput>;
diff --git a/packages/svelte/tests/server-side-rendering/test.ts b/packages/svelte/tests/server-side-rendering/test.ts
index 2dcaa85708..16f7c422b8 100644
--- a/packages/svelte/tests/server-side-rendering/test.ts
+++ b/packages/svelte/tests/server-side-rendering/test.ts
@@ -6,13 +6,12 @@
 
 import * as fs from 'node:fs';
 import { assert } from 'vitest';
-import { render } from 'svelte/server';
+import { render, type SyncRenderOutput } from 'svelte/server';
 import { compile_directory, should_update_expected, try_read_file } from '../helpers.js';
 import { assert_html_equal_with_options } from '../html_equal.js';
 import { suite_with_variants, type BaseTest } from '../suite.js';
 import type { CompileOptions } from '#compiler';
 import { seen } from '../../src/internal/server/dev.js';
-import type { SyncRenderOutput } from '#server';
 
 interface SSRTest extends BaseTest {
 	mode?: ('sync' | 'async')[];
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index b752ef5e07..5fcae1b2e0 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -2616,11 +2616,11 @@ declare module 'svelte/server' {
 					}
 				]
 	): RenderOutput;
-	type Csp = { nonce?: string; hash?: boolean };
+	export type Csp = { nonce?: string; hash?: boolean };
 
-	type Sha256Source = `sha256-${string}`;
+	export type Sha256Source = `sha256-${string}`;
 
-	interface SyncRenderOutput {
+	export interface SyncRenderOutput {
 		/** HTML that goes into the `<head>` */
 		head: string;
 		/** @deprecated use `body` instead */
@@ -2632,7 +2632,7 @@ declare module 'svelte/server' {
 		};
 	}
 
-	type RenderOutput = SyncRenderOutput & PromiseLike<SyncRenderOutput>;
+	export type RenderOutput = SyncRenderOutput & PromiseLike<SyncRenderOutput>;
 
 	export {};
 }

From f5f70343df452f32c6a1ea918bb458d8117706ce Mon Sep 17 00:00:00 2001
From: Liam O'Dea <liam.j.odea@gmail.com>
Date: Thu, 20 Aug 2026 23:11:14 +0200
Subject: [PATCH 152/222] =?UTF-8?q?perf:=20O(n=C2=B2)=E2=86=92O(n)=20Map?=
 =?UTF-8?q?=20lookups=20for=20legacy=20reactive=20statements=20(#18602)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .changeset/legacy-reactive-map-lookups.md                    | 5 +++++
 packages/svelte/src/compiler/phases/2-analyze/index.js       | 3 ++-
 .../compiler/phases/3-transform/client/transform-client.js   | 4 ++--
 .../compiler/phases/3-transform/server/transform-server.js   | 4 ++--
 4 files changed, 11 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/legacy-reactive-map-lookups.md

diff --git a/.changeset/legacy-reactive-map-lookups.md b/.changeset/legacy-reactive-map-lookups.md
new file mode 100644
index 0000000000..ec6f4fbf9d
--- /dev/null
+++ b/.changeset/legacy-reactive-map-lookups.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+perf: O(n²)→O(n) Map lookups for legacy `$:` reactive statement ordering
diff --git a/packages/svelte/src/compiler/phases/2-analyze/index.js b/packages/svelte/src/compiler/phases/2-analyze/index.js
index f9cf2f1d89..1fd83e65b9 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/index.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/index.js
@@ -1318,7 +1318,8 @@ function order_reactive_statements(unsorted_reactive_declarations) {
 	 * @returns
 	 */
 	const add_declaration = (node, declaration) => {
-		if ([...reactive_declarations.values()].includes(declaration)) return;
+		// Visited set: each ReactiveStatement is stored under exactly one LabeledStatement node
+		if (reactive_declarations.has(node)) return;
 
 		for (const binding of declaration.dependencies) {
 			if (declaration.assignments.has(binding)) continue;
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js b/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js
index 552fe89960..cbb5f2eac7 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js
@@ -247,11 +247,11 @@ export function client_component(analysis, options) {
 	}
 
 	for (const [node] of analysis.reactive_statements) {
-		const statement = [...state.legacy_reactive_statements].find(([n]) => n === node);
+		const statement = state.legacy_reactive_statements.get(node);
 		if (statement === undefined) {
 			throw new Error('Could not find reactive statement');
 		}
-		instance.body.push(statement[1]);
+		instance.body.push(statement);
 	}
 
 	if (analysis.reactive_statements.size > 0) {
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js b/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
index 24ca58bb41..0a533aec37 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
@@ -148,7 +148,7 @@ export function server_component(analysis, options) {
 	const legacy_reactive_declarations = [];
 
 	for (const [node] of analysis.reactive_statements) {
-		const statement = [...state.legacy_reactive_statements].find(([n]) => n === node);
+		const statement = state.legacy_reactive_statements.get(node);
 		if (statement === undefined) {
 			throw new Error('Could not find reactive statement');
 		}
@@ -165,7 +165,7 @@ export function server_component(analysis, options) {
 			}
 		}
 
-		instance.body.push(statement[1]);
+		instance.body.push(statement);
 	}
 
 	if (legacy_reactive_declarations.length > 0) {

From f4918d86f3f82cb03535836c329457b1a57e1fdb Mon Sep 17 00:00:00 2001
From: Jared Dunham <dunhamjared130@gmail.com>
Date: Thu, 20 Aug 2026 16:30:04 -0500
Subject: [PATCH 153/222] docs: added generic type parameter example for $state
 (#18494)

---
 documentation/docs/07-misc/03-typescript.md | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/documentation/docs/07-misc/03-typescript.md b/documentation/docs/07-misc/03-typescript.md
index b7f49f9c6f..daa73b5e98 100644
--- a/documentation/docs/07-misc/03-typescript.md
+++ b/documentation/docs/07-misc/03-typescript.md
@@ -170,6 +170,12 @@ If you don't give `$state` an initial value, part of its types will be `undefine
 let count: number = $state();
 ```
 
+You can pass the type directly as a generic parameter to safely handle this. TypeScript will infer the variable as `number | undefined`.
+
+```ts
+let count = $state<number>();
+```
+
 If you know that the variable _will_ be defined before you first use it, use an `as` casting. This is especially useful in the context of classes:
 
 ```ts

From 38ef714f1a2fa0e74b60e74ca46a8977ddac26b7 Mon Sep 17 00:00:00 2001
From: Kamil Jakubus <kamiljkbz@protonmail.com>
Date: Thu, 20 Aug 2026 23:30:19 +0200
Subject: [PATCH 154/222] fix: scope SSR boundary failed snippets to their
 boundary (#18593)

Each `<svelte:boundary>` with:

```svelte
{#snippet failed(error)}
  ...
{/snippet}
```

generated a function named failed. Sibling boundaries placed both
functions in the same SSR scope:

```js
{
  function failed() {}
  function failed() {} // Identifier `failed` has already been declared
}
```

Resulting in a `[PARSE_ERROR] Identifier `failed` has already been
declared` error during build time.

A let declaration such as `{const x = 0}` can create a nested lexical
block, exposing the collision.

The fix gives each boundary its own scope:

```js
{
  function failed() {}
  $$renderer.boundary({ failed }, ...);
}

{
  function failed() {}
  $$renderer.boundary({ failed }, ...);
}
``
---
 .changeset/young-papers-hide.md                     |  5 +++++
 .../3-transform/server/visitors/SvelteBoundary.js   | 13 +++++++++----
 .../_expected.html                                  |  1 +
 .../boundary-duplicate-failed-snippets/main.svelte  | 11 +++++++++++
 4 files changed, 26 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/young-papers-hide.md
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/boundary-duplicate-failed-snippets/_expected.html
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/boundary-duplicate-failed-snippets/main.svelte

diff --git a/.changeset/young-papers-hide.md b/.changeset/young-papers-hide.md
new file mode 100644
index 0000000000..7df1f114b9
--- /dev/null
+++ b/.changeset/young-papers-hide.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: scope SSR boundary failed snippets to their boundary
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteBoundary.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteBoundary.js
index 47a07a1312..feef4bd1a9 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteBoundary.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteBoundary.js
@@ -1,4 +1,4 @@
-/** @import { BlockStatement } from 'estree' */
+/** @import { BlockStatement, Statement } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types' */
 import * as b from '#compiler/builders';
@@ -84,6 +84,9 @@ export function SvelteBoundary(node, context) {
 	}
 
 	const props = b.object([]);
+	/** @type {Statement[]} */
+	const init = [];
+
 	if (failed_attribute && !failed_snippet) {
 		const failed_callee = build_attribute_value(
 			failed_attribute.value,
@@ -95,13 +98,15 @@ export function SvelteBoundary(node, context) {
 
 		props.properties.push(b.init('failed', failed_callee));
 	} else if (failed_snippet) {
-		context.visit(failed_snippet, context.state);
+		context.visit(failed_snippet, { ...context.state, init });
 		props.properties.push(b.init('failed', failed_snippet.expression));
 	}
 
-	context.state.template.push(
-		b.stmt(b.call('$$renderer.boundary', props, b.arrow([b.id('$$renderer')], children_body)))
+	const boundary = b.stmt(
+		b.call('$$renderer.boundary', props, b.arrow([b.id('$$renderer')], children_body))
 	);
+
+	context.state.template.push(init.length > 0 ? b.block([...init, boundary]) : boundary);
 }
 
 /**
diff --git a/packages/svelte/tests/server-side-rendering/samples/boundary-duplicate-failed-snippets/_expected.html b/packages/svelte/tests/server-side-rendering/samples/boundary-duplicate-failed-snippets/_expected.html
new file mode 100644
index 0000000000..7c89b545c5
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/boundary-duplicate-failed-snippets/_expected.html
@@ -0,0 +1 @@
+<div></div>
diff --git a/packages/svelte/tests/server-side-rendering/samples/boundary-duplicate-failed-snippets/main.svelte b/packages/svelte/tests/server-side-rendering/samples/boundary-duplicate-failed-snippets/main.svelte
new file mode 100644
index 0000000000..126c9ea304
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/boundary-duplicate-failed-snippets/main.svelte
@@ -0,0 +1,11 @@
+<div>
+	{const x = 0}
+
+	<svelte:boundary>
+		{#snippet failed()}{/snippet}
+	</svelte:boundary>
+
+	<svelte:boundary>
+		{#snippet failed()}{/snippet}
+	</svelte:boundary>
+</div>

From 07dda4056b56024dd263eb93c8d7d1c16c9a72d6 Mon Sep 17 00:00:00 2001
From: AminBouchareb <93881530+el-amin-dev@users.noreply.github.com>
Date: Thu, 20 Aug 2026 22:30:33 +0100
Subject: [PATCH 155/222] docs: document rune_missing_parentheses compiler
 error (#18589)

---
 .../docs/98-reference/.generated/compile-errors.md   | 12 ++++++++++++
 packages/svelte/messages/compile-errors/script.md    | 12 ++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/documentation/docs/98-reference/.generated/compile-errors.md b/documentation/docs/98-reference/.generated/compile-errors.md
index 0d25173711..02e762dc48 100644
--- a/documentation/docs/98-reference/.generated/compile-errors.md
+++ b/documentation/docs/98-reference/.generated/compile-errors.md
@@ -821,6 +821,18 @@ Cannot use `%rune%` rune in non-runes mode
 Cannot use rune without parentheses
 ```
 
+Runes are keywords rather than values — they can't be assigned to a variable or passed to a function, only called. Referencing one without parentheses is therefore an error...
+
+```js
+let count = $state;
+```
+
+...whether it's a rune like `$state` or one reached through a property, like `$derived.by`. Add the parentheses, along with any arguments the rune expects:
+
+```js
+let count = $state(0);
+```
+
 ### rune_removed
 
 ```
diff --git a/packages/svelte/messages/compile-errors/script.md b/packages/svelte/messages/compile-errors/script.md
index 743fe31fde..9980db4c19 100644
--- a/packages/svelte/messages/compile-errors/script.md
+++ b/packages/svelte/messages/compile-errors/script.md
@@ -186,6 +186,18 @@ This turned out to be buggy and unpredictable, particularly when working with de
 
 > Cannot use rune without parentheses
 
+Runes are keywords rather than values — they can't be assigned to a variable or passed to a function, only called. Referencing one without parentheses is therefore an error...
+
+```js
+let count = $state;
+```
+
+...whether it's a rune like `$state` or one reached through a property, like `$derived.by`. Add the parentheses, along with any arguments the rune expects:
+
+```js
+let count = $state(0);
+```
+
 ## rune_removed
 
 > The `%name%` rune has been removed

From 793e309d4e2c2442ad62e5b44d5ded5ee530fd2a Mon Sep 17 00:00:00 2001
From: john gravois <jgravois@compiler.la>
Date: Thu, 20 Aug 2026 14:41:46 -0700
Subject: [PATCH 156/222] docs: fix typo in basic markup doc (#18434)

the current example in the docs conflates two different (commonly
associated) words.


https://www.reddit.com/r/namenerds/comments/1m6yiw6/what_do_we_think_of_the_name_aretha/
---
 documentation/docs/03-template-syntax/01-basic-markup.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/documentation/docs/03-template-syntax/01-basic-markup.md b/documentation/docs/03-template-syntax/01-basic-markup.md
index 436f307f84..89e01cf1ed 100644
--- a/documentation/docs/03-template-syntax/01-basic-markup.md
+++ b/documentation/docs/03-template-syntax/01-basic-markup.md
@@ -202,7 +202,7 @@ You can add a special comment starting with `@component` that will show up when
 - You can also use code blocks here.
 - Usage:
   ```html
-  <Main name="Arethra">
+  <Main name="Aretha">
   ```
 -->
 <script>

From 44bd73f3e59f7f9f74ed16bb577d355a71d895f1 Mon Sep 17 00:00:00 2001
From: Hyunbin Seo <47051820+hyunbinseo@users.noreply.github.com>
Date: Fri, 21 Aug 2026 06:43:25 +0900
Subject: [PATCH 157/222] =?UTF-8?q?docs:=20replace=20N-ary=20times=20`?=
 =?UTF-8?q?=E2=A8=89`=20with=20multiplication=20sign=20`=C3=97`=20(#18418)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Replaces the incorrect N-Ary Times Operator `⨉` (U+2A09) with the
correct Multiplication Sign `×` (U+00D7) in the box dimension label.
Former is intended for mathematical set theory and type theory contexts.
For physical dimensions (width × height), `×` is the correct symbol.
---
 documentation/docs/03-template-syntax/11-declaration-tags.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/documentation/docs/03-template-syntax/11-declaration-tags.md b/documentation/docs/03-template-syntax/11-declaration-tags.md
index e0edaf6a38..2ae1214b9c 100644
--- a/documentation/docs/03-template-syntax/11-declaration-tags.md
+++ b/documentation/docs/03-template-syntax/11-declaration-tags.md
@@ -13,7 +13,7 @@ Declaration tags define local variables inside markup with `const` or `let`:
 
 {#each boxes as box}
 	{const area = box.width * box.height}
-	{const label = `${box.width} ⨉ ${box.height} = ${area}`}
+	{const label = `${box.width} × ${box.height} = ${area}`}
 
 	<p>{label}</p>
 {/each}

From 09a67efcfcc9c67a402d57408451d43403ee89c1 Mon Sep 17 00:00:00 2001
From: Alexander Kireyev <ak.chatman.media@gmail.com>
Date: Fri, 21 Aug 2026 04:51:33 +0700
Subject: [PATCH 158/222] fix: warn on undeclared shorthand event handlers on
 svelte:window/document/body (#18480)

Same as we already did on regular elements.
Fixes #18275

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/cool-spoons-tap.md                 |  5 +++
 .../phases/2-analyze/visitors/SvelteBody.js   |  8 ++--
 .../2-analyze/visitors/SvelteDocument.js      |  8 ++--
 .../phases/2-analyze/visitors/SvelteWindow.js |  8 ++--
 .../2-analyze/visitors/shared/element.js      | 10 +----
 .../phases/2-analyze/visitors/shared/utils.js | 24 +++++++++++-
 .../_config.js                                |  3 ++
 .../input.svelte                              |  7 ++++
 .../warnings.json                             | 38 +++++++++++++++++++
 9 files changed, 90 insertions(+), 21 deletions(-)
 create mode 100644 .changeset/cool-spoons-tap.md
 create mode 100644 packages/svelte/tests/validator/samples/global-event-reference-special-elements/_config.js
 create mode 100644 packages/svelte/tests/validator/samples/global-event-reference-special-elements/input.svelte
 create mode 100644 packages/svelte/tests/validator/samples/global-event-reference-special-elements/warnings.json

diff --git a/.changeset/cool-spoons-tap.md b/.changeset/cool-spoons-tap.md
new file mode 100644
index 0000000000..461db03a81
--- /dev/null
+++ b/.changeset/cool-spoons-tap.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: warn on undeclared shorthand event handlers on `<svelte:window>`, `<svelte:document>` and `<svelte:body>`
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteBody.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteBody.js
index 82bc592c14..39b559b32f 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteBody.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteBody.js
@@ -3,6 +3,7 @@
 import * as e from '../../../errors.js';
 import { is_event_attribute } from '../../../utils/ast.js';
 import { disallow_children } from './shared/special-element.js';
+import { check_global_event_reference } from './shared/utils.js';
 
 /**
  * @param {AST.SvelteBody} node
@@ -11,10 +12,9 @@ import { disallow_children } from './shared/special-element.js';
 export function SvelteBody(node, context) {
 	disallow_children(node);
 	for (const attribute of node.attributes) {
-		if (
-			attribute.type === 'SpreadAttribute' ||
-			(attribute.type === 'Attribute' && !is_event_attribute(attribute))
-		) {
+		if (attribute.type === 'Attribute' && is_event_attribute(attribute)) {
+			check_global_event_reference(attribute, context);
+		} else if (attribute.type === 'SpreadAttribute' || attribute.type === 'Attribute') {
 			e.svelte_body_illegal_attribute(attribute);
 		}
 	}
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteDocument.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteDocument.js
index fe54ebf30d..23e984f607 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteDocument.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteDocument.js
@@ -3,6 +3,7 @@
 import { disallow_children } from './shared/special-element.js';
 import * as e from '../../../errors.js';
 import { is_event_attribute } from '../../../utils/ast.js';
+import { check_global_event_reference } from './shared/utils.js';
 
 /**
  * @param {AST.SvelteDocument} node
@@ -12,10 +13,9 @@ export function SvelteDocument(node, context) {
 	disallow_children(node);
 
 	for (const attribute of node.attributes) {
-		if (
-			attribute.type === 'SpreadAttribute' ||
-			(attribute.type === 'Attribute' && !is_event_attribute(attribute))
-		) {
+		if (attribute.type === 'Attribute' && is_event_attribute(attribute)) {
+			check_global_event_reference(attribute, context);
+		} else if (attribute.type === 'SpreadAttribute' || attribute.type === 'Attribute') {
 			e.illegal_element_attribute(attribute, 'svelte:document');
 		}
 	}
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteWindow.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteWindow.js
index 20f5abc5d6..5281c7a635 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteWindow.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteWindow.js
@@ -3,6 +3,7 @@
 import { disallow_children } from './shared/special-element.js';
 import * as e from '../../../errors.js';
 import { is_event_attribute } from '../../../utils/ast.js';
+import { check_global_event_reference } from './shared/utils.js';
 
 /**
  * @param {AST.SvelteWindow} node
@@ -12,10 +13,9 @@ export function SvelteWindow(node, context) {
 	disallow_children(node);
 
 	for (const attribute of node.attributes) {
-		if (
-			attribute.type === 'SpreadAttribute' ||
-			(attribute.type === 'Attribute' && !is_event_attribute(attribute))
-		) {
+		if (attribute.type === 'Attribute' && is_event_attribute(attribute)) {
+			check_global_event_reference(attribute, context);
+		} else if (attribute.type === 'SpreadAttribute' || attribute.type === 'Attribute') {
 			e.illegal_element_attribute(attribute, 'svelte:window');
 		}
 	}
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/element.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/element.js
index ff02dee02a..6a0c58ca30 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/element.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/element.js
@@ -9,6 +9,7 @@ import {
 	validate_attribute_name,
 	validate_slot_attribute
 } from './attribute.js';
+import { check_global_event_reference } from './utils.js';
 
 const EVENT_MODIFIERS = [
 	'preventDefault',
@@ -64,14 +65,7 @@ export function validate_element(node, context) {
 					e.attribute_invalid_event_handler(attribute);
 				}
 
-				const value = get_attribute_expression(attribute);
-				if (
-					value.type === 'Identifier' &&
-					value.name === attribute.name &&
-					!context.state.scope.get(value.name)
-				) {
-					w.attribute_global_event_reference(attribute, attribute.name);
-				}
+				check_global_event_reference(attribute, context);
 			}
 
 			if (attribute.name === 'slot') {
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/utils.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/utils.js
index 35116d715a..a32355abf5 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/utils.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/utils.js
@@ -4,7 +4,11 @@
 /** @import { Scope } from '../../../scope' */
 /** @import { NodeLike } from '../../../../errors.js' */
 import * as e from '../../../../errors.js';
-import { extract_identifiers, get_parent } from '../../../../utils/ast.js';
+import {
+	extract_identifiers,
+	get_attribute_expression,
+	get_parent
+} from '../../../../utils/ast.js';
 import * as w from '../../../../warnings.js';
 import * as b from '#compiler/builders';
 import { get_rune } from '../../../scope.js';
@@ -298,3 +302,21 @@ export function validate_export(node, scope, name) {
 		e.state_invalid_export(node);
 	}
 }
+
+/**
+ * Warns when an event attribute uses the shorthand form (`{onclick}`) but the
+ * referenced name isn't declared, so it silently resolves to the global handler.
+ * @param {AST.Attribute & { value: [AST.ExpressionTag] | AST.ExpressionTag }} attribute
+ * @param {Context} context
+ */
+export function check_global_event_reference(attribute, context) {
+	const value = get_attribute_expression(attribute);
+
+	if (
+		value.type === 'Identifier' &&
+		value.name === attribute.name &&
+		!context.state.scope.get(value.name)
+	) {
+		w.attribute_global_event_reference(attribute, attribute.name);
+	}
+}
diff --git a/packages/svelte/tests/validator/samples/global-event-reference-special-elements/_config.js b/packages/svelte/tests/validator/samples/global-event-reference-special-elements/_config.js
new file mode 100644
index 0000000000..f47bee71df
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/global-event-reference-special-elements/_config.js
@@ -0,0 +1,3 @@
+import { test } from '../../test';
+
+export default test({});
diff --git a/packages/svelte/tests/validator/samples/global-event-reference-special-elements/input.svelte b/packages/svelte/tests/validator/samples/global-event-reference-special-elements/input.svelte
new file mode 100644
index 0000000000..3ea7674419
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/global-event-reference-special-elements/input.svelte
@@ -0,0 +1,7 @@
+<script>
+	let onkeydown;
+</script>
+
+<svelte:window {onkeydown} {onresize} />
+<svelte:document {onvisibilitychange} />
+<svelte:body {onfocus} />
diff --git a/packages/svelte/tests/validator/samples/global-event-reference-special-elements/warnings.json b/packages/svelte/tests/validator/samples/global-event-reference-special-elements/warnings.json
new file mode 100644
index 0000000000..e69a45ab3e
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/global-event-reference-special-elements/warnings.json
@@ -0,0 +1,38 @@
+[
+	{
+		"code": "attribute_global_event_reference",
+		"message": "You are referencing `globalThis.onresize`. Did you forget to declare a variable with that name?",
+		"start": {
+			"column": 27,
+			"line": 5
+		},
+		"end": {
+			"column": 37,
+			"line": 5
+		}
+	},
+	{
+		"code": "attribute_global_event_reference",
+		"message": "You are referencing `globalThis.onvisibilitychange`. Did you forget to declare a variable with that name?",
+		"start": {
+			"column": 17,
+			"line": 6
+		},
+		"end": {
+			"column": 37,
+			"line": 6
+		}
+	},
+	{
+		"code": "attribute_global_event_reference",
+		"message": "You are referencing `globalThis.onfocus`. Did you forget to declare a variable with that name?",
+		"start": {
+			"column": 13,
+			"line": 7
+		},
+		"end": {
+			"column": 22,
+			"line": 7
+		}
+	}
+]

From 2d2e5df26e0defc3ad5d0feb3b61e86a7145633f Mon Sep 17 00:00:00 2001
From: Khaled Waleed <foxilated@gmail.com>
Date: Fri, 21 Aug 2026 13:58:47 +0300
Subject: [PATCH 159/222] fix: don't turn component instances stored in $state
 into state proxies (#18646)

Fixes #18416.

We previously said that we don't want to handle component instances specifically when they're wrapped with state in  #16747 - though the use case presented back then was much more arcane than the one in #18416. Therefore we now don't proxify component instances anymore, which also makes the dev time proxy warning obsolete.

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/olive-crabs-refuse.md              |  5 +++++
 .../.generated/client-warnings.md             | 21 -------------------
 .../messages/client-warnings/warnings.md      | 19 -----------------
 .../svelte/src/internal/client/constants.js   |  2 ++
 .../svelte/src/internal/client/context.js     | 14 +++++++++++--
 .../client/dom/elements/bindings/this.js      |  9 ++++++--
 packages/svelte/src/internal/client/proxy.js  | 11 +++++++---
 packages/svelte/src/internal/client/render.js | 12 ++++-------
 .../svelte/src/internal/client/warnings.js    | 11 ----------
 .../Child.svelte                              |  7 +++++++
 .../_config.js                                | 15 +++++++++++++
 .../bind-this-component-in-state-dev/data.js  |  1 +
 .../main.svelte                               | 11 ++++++++++
 .../bind-this-component-in-state/Child.svelte |  7 +++++++
 .../bind-this-component-in-state/_config.js   | 11 ++++++++++
 .../bind-this-component-in-state/data.js      |  1 +
 .../bind-this-component-in-state/main.svelte  | 11 ++++++++++
 17 files changed, 102 insertions(+), 66 deletions(-)
 create mode 100644 .changeset/olive-crabs-refuse.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state-dev/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state-dev/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state-dev/data.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state-dev/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state/data.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state/main.svelte

diff --git a/.changeset/olive-crabs-refuse.md b/.changeset/olive-crabs-refuse.md
new file mode 100644
index 0000000000..a928ae7f19
--- /dev/null
+++ b/.changeset/olive-crabs-refuse.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: don't turn component instances stored in `$state` into state proxies
diff --git a/documentation/docs/98-reference/.generated/client-warnings.md b/documentation/docs/98-reference/.generated/client-warnings.md
index 73c97c253c..75eff181f9 100644
--- a/documentation/docs/98-reference/.generated/client-warnings.md
+++ b/documentation/docs/98-reference/.generated/client-warnings.md
@@ -339,27 +339,6 @@ Reactive `$state(...)` proxies and the values they proxy have different identiti
 
 To resolve this, ensure you're comparing values where both values were created with `$state(...)`, or neither were. Note that `$state.raw(...)` will _not_ create a state proxy.
 
-### state_proxy_unmount
-
-```
-Tried to unmount a state proxy, rather than a component
-```
-
-`unmount` was called with a state proxy:
-
-```js
-import { mount, unmount } from 'svelte';
-import Component from './Component.svelte';
-let target = document.body;
-// ---cut---
-let component = $state(mount(Component, { target }));
-
-// later...
-unmount(component);
-```
-
-Avoid using `$state` here. If `component` _does_ need to be reactive for some reason, use `$state.raw` instead.
-
 ### svelte_boundary_reset_noop
 
 ```
diff --git a/packages/svelte/messages/client-warnings/warnings.md b/packages/svelte/messages/client-warnings/warnings.md
index 58d00f3933..ac2e103ffe 100644
--- a/packages/svelte/messages/client-warnings/warnings.md
+++ b/packages/svelte/messages/client-warnings/warnings.md
@@ -295,25 +295,6 @@ To silence the warning, ensure that `value`:
 
 To resolve this, ensure you're comparing values where both values were created with `$state(...)`, or neither were. Note that `$state.raw(...)` will _not_ create a state proxy.
 
-## state_proxy_unmount
-
-> Tried to unmount a state proxy, rather than a component
-
-`unmount` was called with a state proxy:
-
-```js
-import { mount, unmount } from 'svelte';
-import Component from './Component.svelte';
-let target = document.body;
-// ---cut---
-let component = $state(mount(Component, { target }));
-
-// later...
-unmount(component);
-```
-
-Avoid using `$state` here. If `component` _does_ need to be reactive for some reason, use `$state.raw` instead.
-
 ## svelte_boundary_reset_noop
 
 > A `<svelte:boundary>` `reset` function only resets the boundary the first time it is called
diff --git a/packages/svelte/src/internal/client/constants.js b/packages/svelte/src/internal/client/constants.js
index 043b50b4b2..b92ea8598b 100644
--- a/packages/svelte/src/internal/client/constants.js
+++ b/packages/svelte/src/internal/client/constants.js
@@ -60,6 +60,8 @@ export const ASYNC = 1 << 22;
 export const ERROR_VALUE = 1 << 23;
 
 export const STATE_SYMBOL = Symbol('$state');
+/** Marks component export objects, so that `proxy(...)` leaves them untouched */
+export const COMPONENT_SYMBOL = Symbol('component');
 export const LEGACY_PROPS = Symbol('legacy props');
 export const LOADING_ATTR_SYMBOL = Symbol('');
 export const PROXY_PATH_SYMBOL = Symbol('proxy path');
diff --git a/packages/svelte/src/internal/client/context.js b/packages/svelte/src/internal/client/context.js
index 0a7b2cdf31..e1571862ed 100644
--- a/packages/svelte/src/internal/client/context.js
+++ b/packages/svelte/src/internal/client/context.js
@@ -5,7 +5,8 @@ import { active_effect, active_reaction } from './runtime.js';
 import { create_user_effect } from './reactivity/effects.js';
 import { async_mode_flag, legacy_mode_flag } from '../flags/index.js';
 import { FILENAME } from '../../constants.js';
-import { BRANCH_EFFECT } from './constants.js';
+import { BRANCH_EFFECT, COMPONENT_SYMBOL } from './constants.js';
+import { define_property } from '../shared/utils.js';
 import { create_context, get_or_init_context_map } from '../shared/context.js';
 
 /** @type {ComponentContext | null} */
@@ -217,7 +218,16 @@ export function pop(component) {
 		dev_current_component_function = component_context?.function ?? null;
 	}
 
-	return component ?? /** @type {T} */ ({});
+	return mark_as_component(component);
+}
+
+/**
+ * Add a symbol to the object (or create one if undefined) to mark it as a component so it isn't proxified.
+ * @param {any} component
+ */
+export function mark_as_component(component = {}) {
+	define_property(component, COMPONENT_SYMBOL, { value: true });
+	return component;
 }
 
 /** @returns {boolean} */
diff --git a/packages/svelte/src/internal/client/dom/elements/bindings/this.js b/packages/svelte/src/internal/client/dom/elements/bindings/this.js
index 52f0c213d3..705adc99ec 100644
--- a/packages/svelte/src/internal/client/dom/elements/bindings/this.js
+++ b/packages/svelte/src/internal/client/dom/elements/bindings/this.js
@@ -1,6 +1,6 @@
 /** @import { ComponentContext, Effect } from '#client' */
 import { DESTROYING, STATE_SYMBOL } from '#client/constants';
-import { component_context } from '../../../context.js';
+import { component_context, mark_as_component } from '../../../context.js';
 import { effect, render_effect } from '../../../reactivity/effects.js';
 import { active_effect, untrack } from '../../../runtime.js';
 
@@ -23,7 +23,12 @@ function is_bound_this(bound_value, element_or_component) {
  * 										returns all the parts of the each block context that are used in the expression
  * @returns {void}
  */
-export function bind_this(element_or_component = {}, update, get_value, get_parts) {
+export function bind_this(
+	element_or_component = mark_as_component(),
+	update,
+	get_value,
+	get_parts
+) {
 	var component_effect = /** @type {ComponentContext} */ (component_context).r;
 	var parent = /** @type {Effect} */ (active_effect);
 
diff --git a/packages/svelte/src/internal/client/proxy.js b/packages/svelte/src/internal/client/proxy.js
index 51333e597f..91d82f8903 100644
--- a/packages/svelte/src/internal/client/proxy.js
+++ b/packages/svelte/src/internal/client/proxy.js
@@ -22,7 +22,7 @@ import {
 	flush_eager_effects,
 	set_eager_effects_deferred
 } from './reactivity/sources.js';
-import { PROXY_PATH_SYMBOL, STATE_SYMBOL } from '#client/constants';
+import { COMPONENT_SYMBOL, PROXY_PATH_SYMBOL, STATE_SYMBOL } from '#client/constants';
 import { UNINITIALIZED } from '../../constants.js';
 import * as e from './errors.js';
 import { tag } from './dev/tracing.js';
@@ -38,8 +38,13 @@ const regex_is_valid_identifier = /^[a-zA-Z_$][a-zA-Z_$0-9]*$/;
  * @returns {T}
  */
 export function proxy(value) {
-	// if non-proxyable, or is already a proxy, return `value`
-	if (typeof value !== 'object' || value === null || STATE_SYMBOL in value) {
+	// if non-proxyable, a component instance, or already a proxy, return `value`
+	if (
+		typeof value !== 'object' ||
+		value === null ||
+		STATE_SYMBOL in value ||
+		COMPONENT_SYMBOL in value
+	) {
 		return value;
 	}
 
diff --git a/packages/svelte/src/internal/client/render.js b/packages/svelte/src/internal/client/render.js
index 50832fb3ff..2abedb3a55 100644
--- a/packages/svelte/src/internal/client/render.js
+++ b/packages/svelte/src/internal/client/render.js
@@ -10,7 +10,7 @@ import {
 } from './dom/operations.js';
 import { HYDRATION_END, HYDRATION_ERROR, HYDRATION_START } from '../../constants.js';
 import { active_effect } from './runtime.js';
-import { push, pop, component_context } from './context.js';
+import { push, pop, component_context, mark_as_component } from './context.js';
 import { component_root } from './reactivity/effects.js';
 import { hydrate_node, hydrating, set_hydrate_node, set_hydrating } from './dom/hydration.js';
 import { array_from } from '../shared/utils.js';
@@ -23,7 +23,7 @@ import * as w from './warnings.js';
 import * as e from './errors.js';
 import { assign_nodes } from './dom/template.js';
 import { is_passive_event } from '../../utils.js';
-import { COMMENT_NODE, STATE_SYMBOL, TEXT_CACHE } from './constants.js';
+import { COMMENT_NODE, TEXT_CACHE } from './constants.js';
 import { boundary } from './dom/blocks/boundary.js';
 
 /**
@@ -193,7 +193,7 @@ function _mount(
 
 				should_intro = intro;
 				// @ts-expect-error the public typings are not what the actual function looks like
-				component = Component(anchor_node, props) || {};
+				component = Component(anchor_node, props) || mark_as_component();
 				should_intro = true;
 
 				if (hydrating) {
@@ -323,11 +323,7 @@ export function unmount(component, options) {
 	}
 
 	if (DEV) {
-		if (STATE_SYMBOL in component) {
-			w.state_proxy_unmount();
-		} else {
-			w.lifecycle_double_unmount();
-		}
+		w.lifecycle_double_unmount();
 	}
 
 	return Promise.resolve();
diff --git a/packages/svelte/src/internal/client/warnings.js b/packages/svelte/src/internal/client/warnings.js
index f4e605ac96..ced1a8b2c3 100644
--- a/packages/svelte/src/internal/client/warnings.js
+++ b/packages/svelte/src/internal/client/warnings.js
@@ -247,17 +247,6 @@ export function state_proxy_equality_mismatch(operator) {
 	}
 }
 
-/**
- * Tried to unmount a state proxy, rather than a component
- */
-export function state_proxy_unmount() {
-	if (DEV) {
-		console.warn(`%c[svelte] state_proxy_unmount\n%cTried to unmount a state proxy, rather than a component\nhttps://svelte.dev/e/state_proxy_unmount`, bold, normal);
-	} else {
-		console.warn(`https://svelte.dev/e/state_proxy_unmount`);
-	}
-}
-
 /**
  * A `<svelte:boundary>` `reset` function only resets the boundary the first time it is called
  */
diff --git a/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state-dev/Child.svelte b/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state-dev/Child.svelte
new file mode 100644
index 0000000000..2eb83744c4
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state-dev/Child.svelte
@@ -0,0 +1,7 @@
+<script>
+	import { items } from './data.js';
+
+	export const myArr = items;
+</script>
+
+<p>child</p>
diff --git a/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state-dev/_config.js b/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state-dev/_config.js
new file mode 100644
index 0000000000..daf97f7da6
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state-dev/_config.js
@@ -0,0 +1,15 @@
+import { test } from '../../test';
+import { items } from './data.js';
+
+export default test({
+	compileOptions: {
+		dev: true
+	},
+
+	html: `<p>child</p>`,
+
+	test({ assert, instance }) {
+		// ensure component instance doesn't get proxified (https://github.com/sveltejs/svelte/issues/18416)
+		assert.ok(instance.get_first().myArr === items);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state-dev/data.js b/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state-dev/data.js
new file mode 100644
index 0000000000..06c15d09e4
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state-dev/data.js
@@ -0,0 +1 @@
+export const items = [{ id: 5, name: 'John' }];
diff --git a/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state-dev/main.svelte b/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state-dev/main.svelte
new file mode 100644
index 0000000000..5f5ecddab2
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state-dev/main.svelte
@@ -0,0 +1,11 @@
+<script>
+	import Child from './Child.svelte';
+
+	const components = $state({});
+
+	export function get_first() {
+		return components.first;
+	}
+</script>
+
+<Child bind:this={components.first} />
diff --git a/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state/Child.svelte b/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state/Child.svelte
new file mode 100644
index 0000000000..2eb83744c4
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state/Child.svelte
@@ -0,0 +1,7 @@
+<script>
+	import { items } from './data.js';
+
+	export const myArr = items;
+</script>
+
+<p>child</p>
diff --git a/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state/_config.js b/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state/_config.js
new file mode 100644
index 0000000000..e845e6932e
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state/_config.js
@@ -0,0 +1,11 @@
+import { test } from '../../test';
+import { items } from './data.js';
+
+export default test({
+	html: `<p>child</p>`,
+
+	test({ assert, instance }) {
+		// ensure component instance doesn't get proxified (https://github.com/sveltejs/svelte/issues/18416)
+		assert.ok(instance.get_first().myArr === items);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state/data.js b/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state/data.js
new file mode 100644
index 0000000000..06c15d09e4
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state/data.js
@@ -0,0 +1 @@
+export const items = [{ id: 5, name: 'John' }];
diff --git a/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state/main.svelte b/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state/main.svelte
new file mode 100644
index 0000000000..5f5ecddab2
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/bind-this-component-in-state/main.svelte
@@ -0,0 +1,11 @@
+<script>
+	import Child from './Child.svelte';
+
+	const components = $state({});
+
+	export function get_first() {
+		return components.first;
+	}
+</script>
+
+<Child bind:this={components.first} />

From 9d0062d60784474ac9e618733e51d8ef6315d13c Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Fri, 21 Aug 2026 07:08:14 -0400
Subject: [PATCH 160/222] fix: make template store subscriptions wait for the
 promise that assigns the store (#18582)

Blockers didn't include analyzing implicit store subscriptions, which could also only happen in the template.

Also needs to defer store unsubscribe until after the async template has settled in case the store value is read after an async blocker, in which case unsubscribe synchronously is too soon.

Fixes https://github.com/sveltejs/kit/issues/15119
---
 .changeset/async-store-sub-blocker.md         |  5 ++++
 .../src/compiler/phases/2-analyze/index.js    | 17 +++++++++++++
 .../3-transform/server/transform-server.js    | 25 +++++++++++++------
 .../async-store-sub-blocker/_config.js        | 14 +++++++++++
 .../async-store-sub-blocker/main.svelte       | 16 ++++++++++++
 .../async-store-sub-teardown/_config.js       | 18 +++++++++++++
 .../async-store-sub-teardown/main.svelte      | 11 ++++++++
 .../samples/async-store-sub-teardown/store.js | 23 +++++++++++++++++
 8 files changed, 122 insertions(+), 7 deletions(-)
 create mode 100644 .changeset/async-store-sub-blocker.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-store-sub-blocker/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-store-sub-blocker/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-store-sub-teardown/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-store-sub-teardown/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-store-sub-teardown/store.js

diff --git a/.changeset/async-store-sub-blocker.md b/.changeset/async-store-sub-blocker.md
new file mode 100644
index 0000000000..0222dac846
--- /dev/null
+++ b/.changeset/async-store-sub-blocker.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: block template store subscriptions on the promise that assigns the store
diff --git a/packages/svelte/src/compiler/phases/2-analyze/index.js b/packages/svelte/src/compiler/phases/2-analyze/index.js
index 1fd83e65b9..45f703901d 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/index.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/index.js
@@ -1228,6 +1228,23 @@ function calculate_blockers(instance, analysis) {
 
 	flush_sync_group();
 
+	// a store subscription must wait on whatever blocks the store itself; this must happen
+	// before function tracing so that functions reading `$store` inherit the blocker
+	for (const [name, binding] of instance.scope.declarations) {
+		if (binding.kind !== 'store_sub') continue;
+
+		const store_blocker = instance.scope.get(name.slice(1))?.blocker;
+		if (!store_blocker) continue;
+
+		if (
+			!binding.blocker ||
+			/** @type {ESTree.SimpleLiteral & { value: number }} */ (binding.blocker.property).value <
+				/** @type {ESTree.SimpleLiteral & { value: number }} */ (store_blocker.property).value
+		) {
+			binding.blocker = store_blocker;
+		}
+	}
+
 	for (const fn of functions) {
 		/** @type {Set<Binding>} */
 		const reads_writes = new Set();
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js b/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
index 0a533aec37..44690a1efe 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
@@ -210,14 +210,25 @@ export function server_component(analysis, options) {
 		];
 	}
 
-	if (
-		[...analysis.instance.scope.declarations.values()].some(
-			(binding) => binding.kind === 'store_sub'
-		)
-	) {
+	const store_subs = [...analysis.instance.scope.declarations.values()].filter(
+		(binding) => binding.kind === 'store_sub'
+	);
+
+	// a blocked subscription is only created once its promise resolves, so its teardown must wait until the render is done
+	const defer_store_teardown = store_subs.some((binding) => binding.blocker);
+
+	if (store_subs.length > 0) {
 		instance.body.unshift(b.var('$$store_subs'));
+
+		const unsubscribe = b.if(
+			b.id('$$store_subs'),
+			b.stmt(b.call('$.unsubscribe_stores', b.id('$$store_subs')))
+		);
+
 		template.body.push(
-			b.if(b.id('$$store_subs'), b.stmt(b.call('$.unsubscribe_stores', b.id('$$store_subs'))))
+			defer_store_teardown
+				? b.stmt(b.call('$$renderer.on_destroy', b.arrow([], b.block([unsubscribe]))))
+				: unsubscribe
 		);
 	}
 
@@ -257,7 +268,7 @@ export function server_component(analysis, options) {
 		);
 	}
 
-	let should_inject_context = dev || analysis.needs_context;
+	let should_inject_context = dev || analysis.needs_context || defer_store_teardown;
 
 	if (should_inject_context) {
 		component_block = b.block([
diff --git a/packages/svelte/tests/runtime-runes/samples/async-store-sub-blocker/_config.js b/packages/svelte/tests/runtime-runes/samples/async-store-sub-blocker/_config.js
new file mode 100644
index 0000000000..896385e609
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-store-sub-blocker/_config.js
@@ -0,0 +1,14 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+// Tests that a store subscription only present in the template waits for the
+// promise that assigns the store instead of subscribing to `undefined`,
+// including when the subscription is read through a function.
+export default test({
+	mode: ['client', 'hydrate', 'async-server'],
+	ssrHtml: '<p>hello</p> <p>hello</p>',
+	async test({ assert, target }) {
+		await tick();
+		assert.htmlEqual(target.innerHTML, '<p>hello</p> <p>hello</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-store-sub-blocker/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-store-sub-blocker/main.svelte
new file mode 100644
index 0000000000..04c707c66d
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-store-sub-blocker/main.svelte
@@ -0,0 +1,16 @@
+<script>
+	import { writable } from 'svelte/store';
+
+	async function get_store() {
+		return writable('hello');
+	}
+
+	const store = await get_store();
+
+	function read() {
+		return $store;
+	}
+</script>
+
+<p>{$store}</p>
+<p>{read()}</p>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-store-sub-teardown/_config.js b/packages/svelte/tests/runtime-runes/samples/async-store-sub-teardown/_config.js
new file mode 100644
index 0000000000..ac60694648
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-store-sub-teardown/_config.js
@@ -0,0 +1,18 @@
+import { test } from '../../test';
+import { counts, reset } from './store.js';
+
+// A blocked store subscription is created after the synchronous part of the
+// render has finished, so the teardown must wait for the async work.
+export default test({
+	mode: ['async-server'],
+
+	before_test() {
+		reset();
+	},
+
+	ssrHtml: '<p>hello</p>',
+
+	test_ssr({ assert }) {
+		assert.deepEqual(counts, { subscribes: 1, unsubscribes: 1 });
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-store-sub-teardown/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-store-sub-teardown/main.svelte
new file mode 100644
index 0000000000..8d17e701d3
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-store-sub-teardown/main.svelte
@@ -0,0 +1,11 @@
+<script>
+	import { store } from './store.js';
+
+	async function get_store() {
+		return store;
+	}
+
+	const s = await get_store();
+</script>
+
+<p>{$s}</p>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-store-sub-teardown/store.js b/packages/svelte/tests/runtime-runes/samples/async-store-sub-teardown/store.js
new file mode 100644
index 0000000000..4922c1b027
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-store-sub-teardown/store.js
@@ -0,0 +1,23 @@
+import { writable } from 'svelte/store';
+
+export const counts = { subscribes: 0, unsubscribes: 0 };
+
+const inner = writable('hello');
+
+export const store = {
+	/** @param {(value: string) => void} fn */
+	subscribe(fn) {
+		counts.subscribes += 1;
+		const unsubscribe = inner.subscribe(fn);
+
+		return () => {
+			counts.unsubscribes += 1;
+			unsubscribe();
+		};
+	}
+};
+
+export function reset() {
+	counts.subscribes = 0;
+	counts.unsubscribes = 0;
+}

From 6266debb21f0a7e6971ac9a117c9180e480022e3 Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Fri, 21 Aug 2026 07:35:44 -0400
Subject: [PATCH 161/222] docs: clarify when `$effect.pre` runs relative to DOM
 updates (#18534)

Related to #16648 - describe the `$effect.pre` in more detail

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/witty-donuts-explain.md                  | 5 +++++
 documentation/docs/02-runes/04-$effect.md           | 2 ++
 documentation/docs/06-runtime/03-lifecycle-hooks.md | 2 +-
 packages/svelte/src/ambient.d.ts                    | 2 +-
 packages/svelte/types/index.d.ts                    | 2 +-
 5 files changed, 10 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/witty-donuts-explain.md

diff --git a/.changeset/witty-donuts-explain.md b/.changeset/witty-donuts-explain.md
new file mode 100644
index 0000000000..6ee8f66da6
--- /dev/null
+++ b/.changeset/witty-donuts-explain.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+chore: clarify when `$effect.pre` runs relative to DOM updates
diff --git a/documentation/docs/02-runes/04-$effect.md b/documentation/docs/02-runes/04-$effect.md
index a13fc7bc46..de18add08f 100644
--- a/documentation/docs/02-runes/04-$effect.md
+++ b/documentation/docs/02-runes/04-$effect.md
@@ -205,6 +205,8 @@ In rare cases, you may need to run code _before_ the DOM updates. For this we ca
 </div>
 ```
 
+`$effect.pre` runs before DOM updates that are scheduled after it, not before every DOM mutation in the flush - DOM of parent components may already be updated. When using [await expressions](await-expressions), block updates like `{#if ...}` and `{#each ...}` in the same component also run before `$effect.pre`.
+
 Apart from the timing, `$effect.pre` works exactly like `$effect`.
 
 ## `$effect.tracking`
diff --git a/documentation/docs/06-runtime/03-lifecycle-hooks.md b/documentation/docs/06-runtime/03-lifecycle-hooks.md
index 95e1c260c1..c714dc2e52 100644
--- a/documentation/docs/06-runtime/03-lifecycle-hooks.md
+++ b/documentation/docs/06-runtime/03-lifecycle-hooks.md
@@ -102,7 +102,7 @@ To implement a chat window that autoscrolls to the bottom when new messages appe
 
 In Svelte 4, we do this with `beforeUpdate`, but this is a flawed approach — it fires before _every_ update, whether it's relevant or not. In the example below, we need to introduce checks like `updatingMessages` to make sure we don't mess with the scroll position when someone toggles dark mode.
 
-With runes, we can use `$effect.pre`, which behaves the same as `$effect` but runs before the DOM is updated. As long as we explicitly reference `messages` inside the effect body, it will run whenever `messages` changes, but _not_ when `theme` changes.
+With runes, we can use `$effect.pre`, which behaves the same as `$effect` but runs before DOM updates scheduled after it (see [$effect.pre]($effect#$effect.pre) for the exact ordering). As long as we explicitly reference `messages` inside the effect body, it will run whenever `messages` changes, but _not_ when `theme` changes.
 
 `beforeUpdate`, and its equally troublesome counterpart `afterUpdate`, are therefore deprecated in Svelte 5.
 
diff --git a/packages/svelte/src/ambient.d.ts b/packages/svelte/src/ambient.d.ts
index ed0a004fa1..a9b2cebe1a 100644
--- a/packages/svelte/src/ambient.d.ts
+++ b/packages/svelte/src/ambient.d.ts
@@ -261,7 +261,7 @@ declare function $effect(fn: () => void | (() => void)): void;
 declare namespace $effect {
 	/**
 	 * Runs code right before a component is mounted to the DOM, and then whenever its dependencies change, i.e. `$state` or `$derived` values.
-	 * The timing of the execution is right before the DOM is updated.
+	 * The timing of the execution is right before the DOM that comes after it is updated; parent DOM may already have been updated by the time it runs.
 	 *
 	 * Example:
 	 * ```ts
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index 5fcae1b2e0..96be34ef9e 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -3481,7 +3481,7 @@ declare function $effect(fn: () => void | (() => void)): void;
 declare namespace $effect {
 	/**
 	 * Runs code right before a component is mounted to the DOM, and then whenever its dependencies change, i.e. `$state` or `$derived` values.
-	 * The timing of the execution is right before the DOM is updated.
+	 * The timing of the execution is right before the DOM that comes after it is updated; parent DOM may already have been updated by the time it runs.
 	 *
 	 * Example:
 	 * ```ts

From b2a24b0426f1a302a3d741526a33555fde28f269 Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Fri, 21 Aug 2026 07:51:00 -0400
Subject: [PATCH 162/222] fix: run `onDestroy` callbacks when a server render
 throws (#18585)

Fixes #18584.

There's multiple parts to this
- abort signal was buggy. It wasn't scoped per render, so cross-talk was possible. Fix by scoping to renderer
- onDestroy callbacks were skipped when something throws. Fix by carefully aborting the rest of the tree, waiting for settle, collect all callbacks and then call them

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/great-hoops-tickle.md              |   5 +
 .../src/internal/server/abort-signal.js       |  17 +-
 .../svelte/src/internal/server/renderer.js    | 190 +++++++++++++-----
 .../src/internal/server/renderer.test.ts      | 173 ++++++++++++++++
 4 files changed, 331 insertions(+), 54 deletions(-)
 create mode 100644 .changeset/great-hoops-tickle.md

diff --git a/.changeset/great-hoops-tickle.md b/.changeset/great-hoops-tickle.md
new file mode 100644
index 0000000000..94b32588f1
--- /dev/null
+++ b/.changeset/great-hoops-tickle.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: run `onDestroy` callbacks when a server render throws
diff --git a/packages/svelte/src/internal/server/abort-signal.js b/packages/svelte/src/internal/server/abort-signal.js
index a769a46e3d..16047bdbb1 100644
--- a/packages/svelte/src/internal/server/abort-signal.js
+++ b/packages/svelte/src/internal/server/abort-signal.js
@@ -1,13 +1,12 @@
-import { STALE_REACTION } from '#client/constants';
+import { ssr_context } from './context.js';
 
-/** @type {AbortController | null} */
-let controller = null;
+export function getAbortSignal() {
+	let context = ssr_context;
 
-export function abort() {
-	controller?.abort(STALE_REACTION);
-	controller = null;
-}
+	while (context !== null) {
+		if (context.r !== null) return context.r.global.get_abort_signal();
+		context = context.p;
+	}
 
-export function getAbortSignal() {
-	return (controller ??= new AbortController()).signal;
+	return new AbortController().signal;
 }
diff --git a/packages/svelte/src/internal/server/renderer.js b/packages/svelte/src/internal/server/renderer.js
index 5fb0bb86d5..1a5199d18e 100644
--- a/packages/svelte/src/internal/server/renderer.js
+++ b/packages/svelte/src/internal/server/renderer.js
@@ -3,7 +3,7 @@
 /** @import { Csp, RenderOutput, SyncRenderOutput, Sha256Source } from '../../server/public.js' */
 /** @import { MaybePromise } from '#shared' */
 import { async_mode_flag } from '../flags/index.js';
-import { abort } from './abort-signal.js';
+import { STALE_REACTION } from '../client/constants.js';
 import { pop, push, set_ssr_context, ssr_context } from './context.js';
 import * as e from './errors.js';
 import * as w from './warnings.js';
@@ -180,7 +180,7 @@ export class Renderer {
 		// prevent unhandled rejections, and attach the promise to the renderer instance
 		// so that rejections correctly cause rendering to fail
 		promise.catch(noop);
-		this.promise = promise;
+		this.promise = this.global.track(promise);
 
 		return promises;
 	}
@@ -225,7 +225,7 @@ export class Renderer {
 				e.await_invalid();
 			}
 
-			child.promise = result;
+			child.promise = child.global.track(result);
 		}
 
 		return child;
@@ -273,7 +273,7 @@ export class Renderer {
 					e.await_invalid();
 				}
 				result.catch(noop);
-				child.promise = result;
+				child.promise = child.global.track(result);
 			}
 		} catch (error) {
 			// synchronous errors are handled here, async errors will be handled in #collect_content_async
@@ -293,12 +293,14 @@ export class Renderer {
 					e.await_invalid();
 				}
 
-				child.promise = /** @type {Promise<unknown>} */ (result).then((transformed) => {
-					set_ssr_context(parent_context);
-					child.#out.push(Renderer.#serialize_failed_boundary(transformed));
-					failed_snippet(child, transformed, noop);
-					child.#out.push(BLOCK_CLOSE);
-				});
+				child.promise = child.global.track(
+					/** @type {Promise<unknown>} */ (result).then((transformed) => {
+						set_ssr_context(parent_context);
+						child.#out.push(Renderer.#serialize_failed_boundary(transformed));
+						failed_snippet(child, transformed, noop);
+						child.#out.push(BLOCK_CLOSE);
+					})
+				);
 				child.promise.catch(noop);
 			} else {
 				child.#out.push(Renderer.#serialize_failed_boundary(result));
@@ -317,8 +319,11 @@ export class Renderer {
 	 */
 	component(fn, component_fn) {
 		push(component_fn);
-		const child = this.child(fn);
-		child.#is_component_body = true;
+		// mark before running so `onDestroy` callbacks are still collected if `fn` throws
+		this.child((renderer) => {
+			renderer.#is_component_body = true;
+			return fn(renderer);
+		});
 		pop();
 	}
 
@@ -626,6 +631,49 @@ export class Renderer {
 		}
 	}
 
+	/**
+	 * Runs every `onDestroy` callback in this renderer tree. On a failed render,
+	 * cleanup errors are suppressed so they do not mask the render error.
+	 * @param {boolean} suppress_errors
+	 */
+	#run_on_destroy(suppress_errors) {
+		let first_error;
+		let has_error = false;
+
+		for (const cleanup of this.#collect_on_destroy()) {
+			try {
+				cleanup();
+			} catch (error) {
+				if (!suppress_errors && !has_error) {
+					first_error = error;
+					has_error = true;
+				}
+			}
+		}
+
+		if (has_error) throw first_error;
+	}
+
+	/**
+	 * @param {'sync' | 'async'} mode
+	 * @param {{ idPrefix?: string; csp?: Csp; transformError?: (error: unknown) => unknown }} options
+	 * @returns {Renderer}
+	 */
+	static #create(mode, options) {
+		if (options.idPrefix?.includes('--')) {
+			e.invalid_id_prefix();
+		}
+
+		return new Renderer(
+			new SSRState(
+				mode,
+				options.idPrefix ? options.idPrefix + '-' : '',
+				options.csp,
+				options.transformError
+			)
+		);
+	}
+
 	/**
 	 * Render a component. Throws if any of the children are performing asynchronous work.
 	 *
@@ -636,13 +684,27 @@ export class Renderer {
 	 */
 	static #render(component, options) {
 		var previous_context = ssr_context;
+		const renderer = Renderer.#create('sync', options);
+		/** @type {AccumulatedContent | undefined} */
+		let result;
+		let render_error;
+		let failed = false;
+
 		try {
-			const renderer = Renderer.#open_render('sync', component, options);
+			try {
+				Renderer.#open_render(renderer, component, options);
+				result = Renderer.#close_render(renderer.#collect_content(), renderer);
+			} catch (error) {
+				render_error = error;
+				failed = true;
+			}
+
+			renderer.#run_on_destroy(failed);
+			if (failed) throw render_error;
 
-			const content = renderer.#collect_content();
-			return Renderer.#close_render(content, renderer);
+			return /** @type {AccumulatedContent} */ (result);
 		} finally {
-			abort();
+			renderer.global.abort();
 			set_ssr_context(previous_context);
 		}
 	}
@@ -657,18 +719,35 @@ export class Renderer {
 	 */
 	static async #render_async(component, options) {
 		const previous_context = ssr_context;
+		const renderer = Renderer.#create('async', options);
+		/** @type {(AccumulatedContent & { hashes: { script: Sha256Source[] } }) | undefined} */
+		let result;
+		let render_error;
+		let failed = false;
 
 		try {
-			const renderer = Renderer.#open_render('async', component, options);
-			const content = await renderer.#collect_content_async();
-			const hydratables = await renderer.#collect_hydratables();
-			if (hydratables !== null) {
-				content.head = hydratables + content.head;
+			try {
+				Renderer.#open_render(renderer, component, options);
+				const content = await renderer.#collect_content_async();
+				const hydratables = await renderer.#collect_hydratables();
+				if (hydratables !== null) {
+					content.head = hydratables + content.head;
+				}
+				result = Renderer.#close_render(content, renderer);
+			} catch (error) {
+				render_error = error;
+				failed = true;
+				renderer.global.abort();
+				await renderer.global.settle();
 			}
-			return Renderer.#close_render(content, renderer);
+
+			renderer.#run_on_destroy(failed);
+			if (failed) throw render_error;
+
+			return /** @type {AccumulatedContent & { hashes: { script: Sha256Source[] } }} */ (result);
 		} finally {
 			set_ssr_context(previous_context);
-			abort();
+			renderer.global.abort();
 		}
 	}
 
@@ -760,28 +839,15 @@ export class Renderer {
 
 	/**
 	 * @template {Record<string, any>} Props
-	 * @param {'sync' | 'async'} mode
+	 * @param {Renderer} renderer
 	 * @param {import('svelte').Component<Props>} component
 	 * @param {{ props?: Omit<Props, '$$slots' | '$$events'>; context?: Map<any, any>; idPrefix?: string; csp?: Csp; transformError?: (error: unknown) => unknown }} options
-	 * @returns {Renderer}
+	 * @returns {void}
 	 */
-	static #open_render(mode, component, options) {
-		if (options.idPrefix?.includes('--')) {
-			e.invalid_id_prefix();
-		}
-
+	static #open_render(renderer, component, options) {
 		var previous_context = ssr_context;
 
 		try {
-			const renderer = new Renderer(
-				new SSRState(
-					mode,
-					options.idPrefix ? options.idPrefix + '-' : '',
-					options.csp,
-					options.transformError
-				)
-			);
-
 			/** @type {SSRContext} */
 			const context = { p: null, c: options.context ?? null, r: renderer };
 			set_ssr_context(context);
@@ -790,8 +856,6 @@ export class Renderer {
 			// @ts-expect-error
 			component(renderer, options.props ?? {});
 			renderer.push(BLOCK_CLOSE);
-
-			return renderer;
 		} finally {
 			set_ssr_context(previous_context);
 		}
@@ -803,10 +867,6 @@ export class Renderer {
 	 * @returns {AccumulatedContent & { hashes: { script: Sha256Source[] } }}
 	 */
 	static #close_render(content, renderer) {
-		for (const cleanup of renderer.#collect_on_destroy()) {
-			cleanup();
-		}
-
 		let head = content.head + renderer.global.get_title();
 		let body = content.body;
 
@@ -890,6 +950,14 @@ export class SSRState {
 	/** @readonly @type {Set<{ hash: string; code: string }>} */
 	css = new Set();
 
+	/** @type {Set<Promise<unknown>>} */
+	#pending = new Set();
+
+	/** @type {AbortController | null} */
+	#controller = null;
+
+	#aborted = false;
+
 	/**
 	 * `transformError` passed to `render`. Called when an error boundary catches an error.
 	 * Throws by default if unset in `render`.
@@ -920,6 +988,38 @@ export class SSRState {
 		this.uid = () => `${id_prefix}s${uid++}`;
 	}
 
+	/**
+	 * @template T
+	 * @param {Promise<T>} promise
+	 * @returns {Promise<T>}
+	 */
+	track(promise) {
+		this.#pending.add(promise);
+		promise.then(
+			() => this.#pending.delete(promise),
+			() => this.#pending.delete(promise)
+		);
+		return promise;
+	}
+
+	async settle() {
+		while (this.#pending.size > 0) {
+			await Promise.allSettled([...this.#pending]);
+		}
+	}
+
+	abort() {
+		if (this.#aborted) return;
+		this.#aborted = true;
+		this.#controller?.abort(STALE_REACTION);
+	}
+
+	get_abort_signal() {
+		const controller = (this.#controller ??= new AbortController());
+		if (this.#aborted) controller.abort(STALE_REACTION);
+		return controller.signal;
+	}
+
 	get_title() {
 		return this.#title.value;
 	}
diff --git a/packages/svelte/src/internal/server/renderer.test.ts b/packages/svelte/src/internal/server/renderer.test.ts
index 8e98c41796..1adfdda64c 100644
--- a/packages/svelte/src/internal/server/renderer.test.ts
+++ b/packages/svelte/src/internal/server/renderer.test.ts
@@ -2,6 +2,7 @@ import { afterAll, beforeAll, describe, expect, test } from 'vitest';
 import { Renderer, SSRState } from './renderer.js';
 import type { Component } from 'svelte';
 import { disable_async_mode_flag, enable_async_mode_flag } from '../flags/index.js';
+import { getAbortSignal } from './abort-signal.js';
 
 test('collects synchronous body content by default', () => {
 	const component = (renderer: Renderer) => {
@@ -466,4 +467,176 @@ describe('async', () => {
 		await Renderer.render(component as unknown as Component);
 		expect(destroyed).toEqual(['c', 'e', 'a', 'b', 'b*', 'd']);
 	});
+
+	test('on_destroy callbacks run when a sync render throws', () => {
+		const destroyed: string[] = [];
+		const component = (renderer: Renderer) => {
+			renderer.component((renderer) => {
+				renderer.on_destroy(() => destroyed.push('a'));
+				renderer.child(() => {
+					throw new Error('boom');
+				});
+			});
+		};
+
+		expect(() => Renderer.render(component as unknown as Component).body).toThrow('boom');
+		expect(destroyed).toEqual(['a']);
+	});
+
+	test('on_destroy callbacks run when an async render rejects', async () => {
+		const destroyed: string[] = [];
+		const component = (renderer: Renderer) => {
+			renderer.component((renderer) => {
+				renderer.on_destroy(() => destroyed.push('a'));
+				renderer.child(async () => {
+					await Promise.resolve();
+					throw new Error('boom');
+				});
+			});
+		};
+
+		await expect(Renderer.render(component as unknown as Component)).rejects.toThrow('boom');
+		expect(destroyed).toEqual(['a']);
+	});
+
+	test('on_destroy waits for in-flight renderers when an async render rejects', async () => {
+		const events: string[] = [];
+		let initialised = false;
+
+		const component = (renderer: Renderer) => {
+			renderer.component((renderer) => {
+				// rejects while the sibling component below is still in flight
+				renderer.child(async () => {
+					await Promise.resolve();
+					throw new Error('boom');
+				});
+
+				renderer.component((renderer) => {
+					renderer.on_destroy(() => events.push(`before-await (initialised: ${initialised})`));
+					renderer.child(async () => {
+						await new Promise((f) => setTimeout(f, 10));
+						initialised = true;
+						renderer.on_destroy(() => events.push('after-await'));
+					});
+				});
+			});
+		};
+
+		await expect(Renderer.render(component as unknown as Component)).rejects.toThrow('boom');
+		expect(events).toEqual(['before-await (initialised: true)', 'after-await']);
+	});
+
+	test('aborts in-flight renderers before waiting for them', async () => {
+		const events: string[] = [];
+		const component = (renderer: Renderer) => {
+			renderer.component((renderer) => {
+				renderer.child(async () => {
+					await Promise.resolve();
+					throw new Error('boom');
+				});
+
+				renderer.component((renderer) => {
+					renderer.on_destroy(() => events.push('destroyed'));
+					renderer.child(async () => {
+						const signal = getAbortSignal();
+						await new Promise((_, reject) => {
+							signal.addEventListener('abort', () => reject(signal.reason), { once: true });
+						});
+					});
+				});
+			});
+		};
+
+		await expect(Renderer.render(component as unknown as Component)).rejects.toThrow('boom');
+		expect(events).toEqual(['destroyed']);
+	});
+
+	test('on_destroy waits for every run invocation when an async render rejects', async () => {
+		const events: string[] = [];
+		let initialised = false;
+		const component = (renderer: Renderer) => {
+			renderer.component((renderer) => {
+				renderer.on_destroy(() => events.push(`destroyed (initialised: ${initialised})`));
+				renderer.run([
+					async () => {
+						await new Promise((resolve) => setTimeout(resolve, 10));
+						initialised = true;
+						renderer.on_destroy(() => events.push('destroyed after await'));
+					}
+				]);
+				renderer.run([
+					async () => {
+						await Promise.resolve();
+						throw new Error('boom');
+					}
+				]);
+			});
+		};
+
+		await expect(Renderer.render(component as unknown as Component)).rejects.toThrow('boom');
+		expect(events).toEqual(['destroyed (initialised: true)', 'destroyed after await']);
+	});
+
+	test('abort signals are scoped to a render', async () => {
+		let signal: AbortSignal;
+		let start!: () => void;
+		let resume!: () => void;
+		const started = new Promise<void>((resolve) => (start = resolve));
+		const resumed = new Promise<void>((resolve) => (resume = resolve));
+		const component = (renderer: Renderer) => {
+			renderer.child(async () => {
+				signal = getAbortSignal();
+				start();
+				await resumed;
+			});
+		};
+
+		const first_render = Promise.resolve(Renderer.render(component as unknown as Component));
+		await started;
+		await Renderer.render((() => {}) as unknown as Component);
+		expect(signal!.aborted).toBe(false);
+
+		resume();
+		await first_render;
+		expect(signal!.aborted).toBe(true);
+	});
+
+	test('a throwing on_destroy callback does not mask a sync render error', () => {
+		const destroyed: string[] = [];
+		const component = (renderer: Renderer) => {
+			renderer.component((renderer) => {
+				renderer.on_destroy(() => {
+					destroyed.push('a');
+					throw new Error('cleanup failed');
+				});
+				renderer.on_destroy(() => destroyed.push('b'));
+				renderer.child(() => {
+					throw new Error('boom');
+				});
+			});
+		};
+
+		expect(() => Renderer.render(component as unknown as Component).body).toThrow('boom');
+		expect(destroyed).toEqual(['a', 'b']);
+	});
+
+	test('a throwing on_destroy callback does not mask an async render error', async () => {
+		const destroyed: string[] = [];
+		const component = (renderer: Renderer) => {
+			renderer.component((renderer) => {
+				renderer.on_destroy(() => {
+					destroyed.push('a');
+					throw new Error('cleanup failed');
+				});
+				renderer.on_destroy(() => destroyed.push('b'));
+				renderer.child(async () => {
+					await Promise.resolve();
+					throw new Error('boom');
+				});
+			});
+		};
+
+		await expect(Renderer.render(component as unknown as Component)).rejects.toThrow('boom');
+		expect(destroyed).toEqual(['a', 'b']);
+	});
 });

From 06c9b7929a1cb5294e7f00faa3d24b7a65556a58 Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Fri, 21 Aug 2026 14:16:19 +0200
Subject: [PATCH 163/222] fix: prevent `selectedcontent` mutation from changing
 the selected option (#18495)

Basically, in a situation like this

```svelte
<script lang="ts">
	let value = $state('A');
</script>

<input oninput={() => {}} />
<select bind:value>
	<button><selectedcontent></selectedcontent></button>
	<option>A</option>
	<option>B</option>
	<option>C</option>
</select>

<style>
	select,::picker(select){
		appearance: base-select;
	}
</style>
```
what happens is that the `oninput` is delegated and so it registers the
global listener (which means it listen on every `oninput` not just the
one from the input). When the select change, the `input` event is
dispatched first, the listener runs, doesn't find an `__input` handler
and returns. Now before the `change` event is emitted, the
`MutationObserver` in `init_select` is triggered by the browser updating
`selectedcontent` and invokes `select_option` with `select.__value`.
However, since the `change` event has yet to fire, `select.__value`
still has the old value, so we "reselect" that. When the change event
runs, the selected option is effectively the old one and the whole thing
breaks.

I had to add the test in `runtime-browser` because JSDom doesn't support
`selectedcontent`
---
 .changeset/tidy-pandas-refuse.md              |  5 +++
 .../client/dom/elements/bindings/select.js    | 32 ++++++++++++++++---
 .../_config.js                                | 22 +++++++++++++
 .../main.svelte                               | 17 ++++++++++
 4 files changed, 71 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/tidy-pandas-refuse.md
 create mode 100644 packages/svelte/tests/runtime-browser/samples/selectedcontent-oninput-interfere/_config.js
 create mode 100644 packages/svelte/tests/runtime-browser/samples/selectedcontent-oninput-interfere/main.svelte

diff --git a/.changeset/tidy-pandas-refuse.md b/.changeset/tidy-pandas-refuse.md
new file mode 100644
index 0000000000..7034a3e267
--- /dev/null
+++ b/.changeset/tidy-pandas-refuse.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: prevent `selectedcontent` mutation from changing the selected option
diff --git a/packages/svelte/src/internal/client/dom/elements/bindings/select.js b/packages/svelte/src/internal/client/dom/elements/bindings/select.js
index e390e23ea0..a408613104 100644
--- a/packages/svelte/src/internal/client/dom/elements/bindings/select.js
+++ b/packages/svelte/src/internal/client/dom/elements/bindings/select.js
@@ -55,11 +55,14 @@ export function select_option(select, value, mounting = false) {
  * @param {HTMLSelectElement} select
  */
 export function init_select(select) {
-	var observer = new MutationObserver(() => {
-		if ('__value' in select) {
-			// @ts-ignore
-			select_option(select, select.__value);
-		}
+	var observer = new MutationObserver((entries) => {
+		// Mutations related to `<selectedcontent>` can never affect the option list.
+		// Reacting to them could revert a user-initiated selection change, because the
+		// records are delivered as soon as any listener returns (e.g. a delegated `input`
+		// handler), which can happen before the `change` handler has updated `__value`
+		if (entries.every(is_selectedcontent_mutation) || !('__value' in select)) return;
+		// @ts-ignore
+		select_option(select, select.__value);
 		// Deliberately don't update the potential binding value,
 		// the model should be preserved unless explicitly changed
 	});
@@ -164,3 +167,22 @@ function get_option_value(option) {
 		return option.value;
 	}
 }
+
+/**
+ * Returns `true` if the mutation stems from the browser mirroring the selected
+ * option's content into `<selectedcontent>`, or from us replacing the
+ * `<selectedcontent>` element with a clone of itself
+ * @param {MutationRecord} entry
+ */
+function is_selectedcontent_mutation(entry) {
+	if (/** @type {Element} */ (entry.target).closest('selectedcontent') !== null) {
+		return true;
+	}
+
+	if (entry.type === 'childList') {
+		var nodes = [...entry.addedNodes, ...entry.removedNodes];
+		return nodes.length > 0 && nodes.every((node) => node.nodeName === 'SELECTEDCONTENT');
+	}
+
+	return false;
+}
diff --git a/packages/svelte/tests/runtime-browser/samples/selectedcontent-oninput-interfere/_config.js b/packages/svelte/tests/runtime-browser/samples/selectedcontent-oninput-interfere/_config.js
new file mode 100644
index 0000000000..d153eceeb7
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/samples/selectedcontent-oninput-interfere/_config.js
@@ -0,0 +1,22 @@
+import { flushSync } from 'svelte';
+import { ok, test } from '../../assert';
+
+export default test({
+	async test({ target, assert }) {
+		const select = target.querySelector('select');
+		ok(select);
+
+		select.value = 'B';
+		select.dispatchEvent(new Event('input', { bubbles: true }));
+
+		// because another element has a delegated `oninput` handler, a global `input`
+		// listener runs and, once it returns, a microtask checkpoint delivers the
+		// mutation records *before* the `change` event — we emulate that checkpoint here
+		await Promise.resolve();
+
+		select.dispatchEvent(new Event('change', { bubbles: true }));
+		flushSync();
+
+		assert.equal(select.value, 'B');
+	}
+});
diff --git a/packages/svelte/tests/runtime-browser/samples/selectedcontent-oninput-interfere/main.svelte b/packages/svelte/tests/runtime-browser/samples/selectedcontent-oninput-interfere/main.svelte
new file mode 100644
index 0000000000..97634042ff
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/samples/selectedcontent-oninput-interfere/main.svelte
@@ -0,0 +1,17 @@
+<script lang="ts">
+	let value = $state('A');
+</script>
+
+<input oninput={() => {}} />
+<select bind:value>
+	<button><selectedcontent></selectedcontent></button>
+	<option>A</option>
+	<option>B</option>
+	<option>C</option>
+</select>
+
+<style>
+	select,::picker(select){
+		appearance: base-select;
+	}
+</style>
\ No newline at end of file

From 8bf9ec87000fffd3805ebaac3586a0502cf92900 Mon Sep 17 00:00:00 2001
From: Barry <91018388+barry166@users.noreply.github.com>
Date: Fri, 21 Aug 2026 21:45:41 +0800
Subject: [PATCH 164/222] docs: clarify $bindable fallback binding requirement
 (#18477)

---
 documentation/docs/02-runes/06-$bindable.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/documentation/docs/02-runes/06-$bindable.md b/documentation/docs/02-runes/06-$bindable.md
index 3675a56b16..a3be662785 100644
--- a/documentation/docs/02-runes/06-$bindable.md
+++ b/documentation/docs/02-runes/06-$bindable.md
@@ -52,3 +52,5 @@ In this case, you can specify a fallback value for when no prop is passed at all
 /// file: FancyInput.svelte
 let { value = $bindable('fallback'), ...props } = $props();
 ```
+
+When a bindable prop has a fallback value, the parent must pass a value other than `undefined` if it uses `bind:`. This avoids ambiguity about which value should apply, since the parent and child should share the same value for a binding.

From 224fcadbd5034f0ac6d89b6f8525a58acde8eed4 Mon Sep 17 00:00:00 2001
From: Rupankar Dutta <rupankardutta5686@gmail.com>
Date: Fri, 21 Aug 2026 19:24:15 +0530
Subject: [PATCH 165/222] fix: route $derived teardown errors through
 invoke_error_boundary (#18486)

Fixes #18485

Two parts to this:
1. explicitly invoke error boundary during teardown errors, else they go missing/bubble up outside the render tree
2. skip destroying/destroyed boundaries will searching a handler

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/boundary-teardown-error-routing.md |  5 +++
 .../src/internal/client/error-handling.js     | 12 +++++-
 .../internal/client/error-handling.test.ts    | 39 +++++++++++++++++++
 .../src/internal/client/reactivity/effects.js |  6 +++
 .../samples/error-boundary-28/Trigger.svelte  | 12 ++++++
 .../samples/error-boundary-28/_config.js      | 23 +++++++++++
 .../samples/error-boundary-28/main.svelte     | 24 ++++++++++++
 7 files changed, 119 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/boundary-teardown-error-routing.md
 create mode 100644 packages/svelte/src/internal/client/error-handling.test.ts
 create mode 100644 packages/svelte/tests/runtime-runes/samples/error-boundary-28/Trigger.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/error-boundary-28/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/error-boundary-28/main.svelte

diff --git a/.changeset/boundary-teardown-error-routing.md b/.changeset/boundary-teardown-error-routing.md
new file mode 100644
index 0000000000..0b2249bf22
--- /dev/null
+++ b/.changeset/boundary-teardown-error-routing.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: route $derived teardown errors through invoke_error_boundary
diff --git a/packages/svelte/src/internal/client/error-handling.js b/packages/svelte/src/internal/client/error-handling.js
index 7c404dd933..a46281d36c 100644
--- a/packages/svelte/src/internal/client/error-handling.js
+++ b/packages/svelte/src/internal/client/error-handling.js
@@ -3,7 +3,14 @@
 import { DEV } from 'esm-env';
 import { FILENAME } from '../../constants.js';
 import { is_firefox } from './dom/operations.js';
-import { ERROR_VALUE, BOUNDARY_EFFECT, REACTION_RAN, EFFECT, DESTROYED } from './constants.js';
+import {
+	ERROR_VALUE,
+	BOUNDARY_EFFECT,
+	REACTION_RAN,
+	EFFECT,
+	DESTROYED,
+	DESTROYING
+} from './constants.js';
 import { define_property, get_descriptor } from '../shared/utils.js';
 import { active_effect, active_reaction } from './runtime.js';
 
@@ -50,7 +57,8 @@ export function invoke_error_boundary(error, effect) {
 	}
 
 	while (effect !== null) {
-		if ((effect.f & BOUNDARY_EFFECT) !== 0) {
+		// Skip boundaries that are destroyed/destroying and cannot meaningfully handle the error.
+		if ((effect.f & BOUNDARY_EFFECT) !== 0 && (effect.f & (DESTROYED | DESTROYING)) === 0) {
 			if ((effect.f & REACTION_RAN) === 0) {
 				// we are still creating the boundary effect
 				throw error;
diff --git a/packages/svelte/src/internal/client/error-handling.test.ts b/packages/svelte/src/internal/client/error-handling.test.ts
new file mode 100644
index 0000000000..2eb6093a2c
--- /dev/null
+++ b/packages/svelte/src/internal/client/error-handling.test.ts
@@ -0,0 +1,39 @@
+import { assert, test } from 'vitest';
+import { BOUNDARY_EFFECT, DESTROYED, REACTION_RAN } from './constants';
+import { invoke_error_boundary } from './error-handling';
+import type { Effect } from './types';
+
+test('ignores errors from a destroyed entry effect', () => {
+	const error = new Error('original');
+	let handled = null;
+	const boundary = {
+		f: BOUNDARY_EFFECT | REACTION_RAN,
+		b: { error: (error: unknown) => (handled = error) },
+		parent: null
+	} as unknown as Effect;
+	const effect = { f: DESTROYED, parent: boundary } as Effect;
+
+	invoke_error_boundary(error, effect);
+
+	assert.equal(handled, null);
+});
+
+test('skips destroyed boundary ancestors without masking the error', () => {
+	const error = new Error('original');
+	let handled = null;
+	const live_boundary = {
+		f: BOUNDARY_EFFECT | REACTION_RAN,
+		b: { error: (error: unknown) => (handled = error) },
+		parent: null
+	} as unknown as Effect;
+	const destroyed_boundary = {
+		f: BOUNDARY_EFFECT | DESTROYED | REACTION_RAN,
+		b: null,
+		parent: live_boundary
+	} as unknown as Effect;
+	const effect = { f: 0, parent: destroyed_boundary } as Effect;
+
+	invoke_error_boundary(error, effect);
+
+	assert.equal(handled, error);
+});
diff --git a/packages/svelte/src/internal/client/reactivity/effects.js b/packages/svelte/src/internal/client/reactivity/effects.js
index c5d195dfae..7e53138aae 100644
--- a/packages/svelte/src/internal/client/reactivity/effects.js
+++ b/packages/svelte/src/internal/client/reactivity/effects.js
@@ -36,6 +36,7 @@ import {
 	MANAGED_EFFECT,
 	DESTROYING
 } from '#client/constants';
+import { invoke_error_boundary } from '../error-handling.js';
 import * as e from '../errors.js';
 import { DEV } from 'esm-env';
 import { define_property } from '../../shared/utils.js';
@@ -449,6 +450,11 @@ export function execute_effect_teardown(effect) {
 		set_active_reaction(null);
 		try {
 			teardown.call(null);
+		} catch (error) {
+			// Route teardown errors through the boundary system so that a live
+			// ancestor <svelte:boundary> can handle them. Boundaries that are
+			// themselves mid-teardown are skipped by invoke_error_boundary.
+			invoke_error_boundary(error, effect.parent);
 		} finally {
 			set_is_destroying_effect(previously_destroying_effect);
 			set_active_reaction(previous_reaction);
diff --git a/packages/svelte/tests/runtime-runes/samples/error-boundary-28/Trigger.svelte b/packages/svelte/tests/runtime-runes/samples/error-boundary-28/Trigger.svelte
new file mode 100644
index 0000000000..46b4bd1c30
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/error-boundary-28/Trigger.svelte
@@ -0,0 +1,12 @@
+<script>
+	let { getValue } = $props();
+
+	// Reads reactive state during teardown
+	$effect(() => {
+		return () => {
+			getValue();
+		};
+	});
+</script>
+
+<span>trigger</span>
diff --git a/packages/svelte/tests/runtime-runes/samples/error-boundary-28/_config.js b/packages/svelte/tests/runtime-runes/samples/error-boundary-28/_config.js
new file mode 100644
index 0000000000..4802089124
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/error-boundary-28/_config.js
@@ -0,0 +1,23 @@
+import { flushSync, tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	// Regression test for https://github.com/sveltejs/svelte/issues/18485.
+	// A $derived that re-executes and throws during teardown should route the
+	// error to a live ancestor boundary.
+	mode: ['client'],
+	async test({ assert, target }) {
+		const [break_it, unmount] = target.querySelectorAll('button');
+
+		break_it.click();
+		flushSync();
+
+		assert.doesNotThrow(() => {
+			unmount.click();
+			flushSync();
+		});
+
+		await tick();
+		assert.htmlEqual(target.innerHTML, '<p>caught</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/error-boundary-28/main.svelte b/packages/svelte/tests/runtime-runes/samples/error-boundary-28/main.svelte
new file mode 100644
index 0000000000..e100be2169
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/error-boundary-28/main.svelte
@@ -0,0 +1,24 @@
+<script>
+	import Trigger from './Trigger.svelte';
+
+	let mounted = $state(true);
+	let broken = $state(false);
+
+	// Throwing derived — nothing in the live template reads `appContext`, so
+	// invalidating it does NOT throw immediately (becomes dirty-and-unread).
+	let data = $derived(broken ? null : { value: 'ok' });
+	let appContext = $derived(data.value);
+</script>
+
+<svelte:boundary>
+	<button onclick={() => (broken = true)}>break</button>
+	<button onclick={() => (mounted = false)}>unmount</button>
+
+	{#if mounted}
+		<Trigger getValue={() => appContext} />
+	{/if}
+
+	{#snippet failed()}
+		<p>caught</p>
+	{/snippet}
+</svelte:boundary>

From a1ec9c8eb7e5fd7e4e02de22e2c18a51ae7aadc7 Mon Sep 17 00:00:00 2001
From: Giorgio Maria Federico Birnthaler
 <129273127+Dodothereal@users.noreply.github.com>
Date: Fri, 21 Aug 2026 16:22:14 +0200
Subject: [PATCH 166/222] chore: fix typo in read_version JSDoc (#18470)

---
 packages/svelte/src/internal/client/runtime.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 4458595d35..e0914b8f70 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -133,7 +133,7 @@ export function set_untracked_writes(value) {
  **/
 export let write_version = 1;
 
-/** @type {number} Used to version each read of a source of derived to avoid duplicating depedencies inside a reaction */
+/** @type {number} Used to version each read of a source of derived to avoid duplicating dependencies inside a reaction */
 let read_version = 0;
 
 export let update_version = read_version;

From 3405b5e735e46aaff057bfa8e5fcdb21391ca89a Mon Sep 17 00:00:00 2001
From: adiGuba <frederic.martini@gmail.com>
Date: Fri, 21 Aug 2026 17:05:32 +0200
Subject: [PATCH 167/222] fix: distinct memoizer on style/class directives
 (#18466)

Fix #18465

The style and classe directives are generated using an unique memoizer for all the class/style directive, which means if you have multiple of the same time on one element you have overly broad invalidation/reruns. This fixes it by having one memoizer call per directive instead of collecting them.

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/lemon-bikes-marry.md               |  5 +++
 .../client/visitors/RegularElement.js         | 22 ++--------
 .../class-directive-memoize/_config.js        | 37 ++++++++++++++++
 .../class-directive-memoize/main.svelte       | 10 +++++
 .../style-directive-memoize/_config.js        | 42 +++++++++++++++++++
 .../style-directive-memoize/main.svelte       | 10 +++++
 6 files changed, 108 insertions(+), 18 deletions(-)
 create mode 100644 .changeset/lemon-bikes-marry.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/class-directive-memoize/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/class-directive-memoize/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/style-directive-memoize/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/style-directive-memoize/main.svelte

diff --git a/.changeset/lemon-bikes-marry.md b/.changeset/lemon-bikes-marry.md
new file mode 100644
index 0000000000..6b1c431a30
--- /dev/null
+++ b/.changeset/lemon-bikes-marry.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: distinct memoizer on style/class directives
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
index 1cf5abeb69..de09d3ef60 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
@@ -4,7 +4,6 @@
 /** @import { Scope } from '../../../scope' */
 import {
 	cannot_be_set_statically,
-	is_boolean_attribute,
 	is_dom_property,
 	is_load_error_element
 } from '../../../../../utils.js';
@@ -13,7 +12,6 @@ import { is_event_attribute, is_text_attribute } from '../../../../utils/ast.js'
 import * as b from '#compiler/builders';
 import {
 	create_attribute,
-	ExpressionMetadata,
 	is_custom_element_node,
 	is_customizable_select_element
 } from '../../../nodes.js';
@@ -528,18 +526,12 @@ export function build_class_directives_object(
 ) {
 	let properties = [];
 
-	const metadata = new ExpressionMetadata();
-
 	for (const d of class_directives) {
-		metadata.merge(d.metadata.expression);
-
 		const expression = /** @type Expression */ (context.visit(d.expression));
-		properties.push(b.init(d.name, expression));
+		properties.push(b.init(d.name, memoizer.add(expression, d.metadata.expression)));
 	}
 
-	const directives = b.object(properties);
-
-	return memoizer.add(directives, metadata);
+	return b.object(properties);
 }
 
 /**
@@ -555,23 +547,17 @@ export function build_style_directives_object(
 	const normal = b.object([]);
 	const important = b.object([]);
 
-	const metadata = new ExpressionMetadata();
-
 	for (const d of style_directives) {
-		metadata.merge(d.metadata.expression);
-
 		const expression =
 			d.value === true
 				? build_getter(b.id(d.name), context.state)
 				: build_attribute_value(d.value, context).value;
 
 		const object = d.modifiers.includes('important') ? important : normal;
-		object.properties.push(b.init(d.name, expression));
+		object.properties.push(b.init(d.name, memoizer.add(expression, d.metadata.expression)));
 	}
 
-	const directives = important.properties.length ? b.array([normal, important]) : normal;
-
-	return memoizer.add(directives, metadata);
+	return important.properties.length ? b.array([normal, important]) : normal;
 }
 
 /**
diff --git a/packages/svelte/tests/runtime-runes/samples/class-directive-memoize/_config.js b/packages/svelte/tests/runtime-runes/samples/class-directive-memoize/_config.js
new file mode 100644
index 0000000000..964993787f
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/class-directive-memoize/_config.js
@@ -0,0 +1,37 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+// This test counts mutations on hydration
+// set_style() should not mutate style on hydration, except if mismatch
+export default test({
+	mode: ['server', 'hydrate', 'client'],
+
+	ssrHtml: `
+		<button>click</button>
+		<div class="red"></div>
+	`,
+
+	html: `
+		<button>click</button>
+		<div class="red"></div>
+	`,
+
+	test({ target, assert, logs }) {
+		flushSync();
+
+		assert.deepEqual(logs, ['is_red()']);
+
+		const btn = target.querySelector('button');
+		const div = target.querySelector('div');
+
+		assert.equal(div?.className, 'red');
+
+		btn?.click();
+
+		flushSync();
+
+		assert.equal(div?.className, 'red active');
+		// only one call here
+		assert.deepEqual(logs, ['is_red()']);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/class-directive-memoize/main.svelte b/packages/svelte/tests/runtime-runes/samples/class-directive-memoize/main.svelte
new file mode 100644
index 0000000000..3a6d02e626
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/class-directive-memoize/main.svelte
@@ -0,0 +1,10 @@
+<script>
+    function is_red() {
+        console.log("is_red()");
+        return "red";
+    }
+
+    let active = $state(false);
+</script>
+<button onclick={() => active = true}>click</button>
+<div class:red={is_red()} class:active></div>
\ No newline at end of file
diff --git a/packages/svelte/tests/runtime-runes/samples/style-directive-memoize/_config.js b/packages/svelte/tests/runtime-runes/samples/style-directive-memoize/_config.js
new file mode 100644
index 0000000000..5638a8ee13
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/style-directive-memoize/_config.js
@@ -0,0 +1,42 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+// This test counts mutations on hydration
+// set_style() should not mutate style on hydration, except if mismatch
+export default test({
+	mode: ['server', 'hydrate', 'client'],
+
+	ssrHtml: `
+		<button>click</button>
+		<div style="background-color: red; font-size: 1em;"></div>
+	`,
+
+	html: `
+		<button>click</button>
+		<div style="background-color: red; font-size: 1em;"></div>
+	`,
+
+	test({ target, assert, logs }) {
+		flushSync();
+
+		assert.deepEqual(logs, ['makeColor()']);
+
+		const btn = target.querySelector('button');
+		const div = target.querySelector('div');
+
+		// Note : we cannot compare HTML because set_style() use dom.style.cssText
+		// which can alter the format of the attribute...
+
+		assert.equal(div?.style.backgroundColor, 'red');
+		assert.equal(div?.style.fontSize, '1em');
+
+		btn?.click();
+
+		flushSync();
+
+		assert.equal(div?.style.backgroundColor, 'red');
+		assert.equal(div?.style.fontSize, '2em');
+		// only one call here
+		assert.deepEqual(logs, ['makeColor()']);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/style-directive-memoize/main.svelte b/packages/svelte/tests/runtime-runes/samples/style-directive-memoize/main.svelte
new file mode 100644
index 0000000000..444d686745
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/style-directive-memoize/main.svelte
@@ -0,0 +1,10 @@
+<script>
+    function makeColor() {
+        console.log("makeColor()");
+        return "red";
+    }
+
+    let size = $state('1em');
+</script>
+<button onclick={() => size = '2em'}>click</button>
+<div style:background-color={makeColor()} style:font-size={size}></div>
\ No newline at end of file

From 3b559bbf96cffb48e782e89aca251e0ca4ccc5bc Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Fri, 21 Aug 2026 16:08:53 -0400
Subject: [PATCH 168/222] fix: avoid NaN keyframe values in slide transition
 (#18430)

Fixes #14205

When a `slide` transition runs on an element without a layout box, for example inside a `display: none` parent, `getComputedStyle` returns values like `auto` for the animated dimensions. These were passed through `parseFloat` unguarded, so the generated css contained `height: NaNpx` and the browser rejected the keyframe property with an "Invalid keyframe value" warning on every transition.

Fix it by omitting properties if they have unparseable numbers - it's the same outcome but you don't see a warning.

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/tough-pandas-shout.md              |  5 ++++
 packages/svelte/src/transition/index.js       | 25 ++++++++++++-----
 .../transition-slide-hidden-parent/_config.js | 27 +++++++++++++++++++
 .../main.svelte                               | 13 +++++++++
 4 files changed, 63 insertions(+), 7 deletions(-)
 create mode 100644 .changeset/tough-pandas-shout.md
 create mode 100644 packages/svelte/tests/runtime-browser/samples/transition-slide-hidden-parent/_config.js
 create mode 100644 packages/svelte/tests/runtime-browser/samples/transition-slide-hidden-parent/main.svelte

diff --git a/.changeset/tough-pandas-shout.md b/.changeset/tough-pandas-shout.md
new file mode 100644
index 0000000000..b0f6ea64fd
--- /dev/null
+++ b/.changeset/tough-pandas-shout.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: avoid `NaN` keyframe values in `slide` transition for elements without a layout box
diff --git a/packages/svelte/src/transition/index.js b/packages/svelte/src/transition/index.js
index 898a929eb1..31e8fbde2b 100644
--- a/packages/svelte/src/transition/index.js
+++ b/packages/svelte/src/transition/index.js
@@ -28,6 +28,17 @@ function split_css_unit(value) {
 	return split ? [parseFloat(split[1]), split[2] || 'px'] : [/** @type {number} */ (value), 'px'];
 }
 
+/**
+ * Omits unresolved dimensions rather than passing invalid values to Web Animations.
+ *
+ * @param {string} property
+ * @param {number} value
+ * @param {number} t
+ */
+function css_dimension(property, value, t) {
+	return Number.isNaN(value) ? '' : `${property}: ${t * value}px;`;
+}
+
 /**
  * Animates a `blur` filter alongside an element's opacity.
  *
@@ -138,13 +149,13 @@ export function slide(node, { delay = 0, duration = 400, easing = cubic_out, axi
 		css: (t) =>
 			'overflow: hidden;' +
 			`opacity: ${Math.min(t * 20, 1) * opacity};` +
-			`${primary_property}: ${t * primary_property_value}px;` +
-			`padding-${secondary_properties[0]}: ${t * padding_start_value}px;` +
-			`padding-${secondary_properties[1]}: ${t * padding_end_value}px;` +
-			`margin-${secondary_properties[0]}: ${t * margin_start_value}px;` +
-			`margin-${secondary_properties[1]}: ${t * margin_end_value}px;` +
-			`border-${secondary_properties[0]}-width: ${t * border_width_start_value}px;` +
-			`border-${secondary_properties[1]}-width: ${t * border_width_end_value}px;` +
+			css_dimension(primary_property, primary_property_value, t) +
+			css_dimension(`padding-${secondary_properties[0]}`, padding_start_value, t) +
+			css_dimension(`padding-${secondary_properties[1]}`, padding_end_value, t) +
+			css_dimension(`margin-${secondary_properties[0]}`, margin_start_value, t) +
+			css_dimension(`margin-${secondary_properties[1]}`, margin_end_value, t) +
+			css_dimension(`border-${secondary_properties[0]}-width`, border_width_start_value, t) +
+			css_dimension(`border-${secondary_properties[1]}-width`, border_width_end_value, t) +
 			`min-${primary_property}: 0`
 	};
 }
diff --git a/packages/svelte/tests/runtime-browser/samples/transition-slide-hidden-parent/_config.js b/packages/svelte/tests/runtime-browser/samples/transition-slide-hidden-parent/_config.js
new file mode 100644
index 0000000000..a8c1e07111
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/samples/transition-slide-hidden-parent/_config.js
@@ -0,0 +1,27 @@
+import { ok, test } from '../../assert';
+
+export default test({
+	async test({ assert, window }) {
+		window.document.querySelector('button')?.click();
+		await new Promise((r) => setTimeout(r, 100));
+
+		const p = window.document.querySelector('p');
+		const animations = /** @type {HTMLElement} */ (p).getAnimations();
+		assert.equal(animations.length, 1);
+
+		// when the element has no layout box, computed dimensions resolve to 'auto',
+		// which must not end up as NaN values that the browser rejects (#14205)
+		const effect = /** @type {KeyframeEffect} */ (animations[0].effect);
+		const keyframes = effect.getKeyframes();
+		ok(keyframes.length > 0);
+		assert.equal(effect.getTiming().duration, 400);
+
+		for (const keyframe of keyframes) {
+			ok(!('height' in keyframe), 'unresolved height should be omitted');
+
+			for (const value of Object.values(keyframe)) {
+				ok(!String(value).includes('NaN'), `unexpected NaN in keyframe: ${value}`);
+			}
+		}
+	}
+});
diff --git a/packages/svelte/tests/runtime-browser/samples/transition-slide-hidden-parent/main.svelte b/packages/svelte/tests/runtime-browser/samples/transition-slide-hidden-parent/main.svelte
new file mode 100644
index 0000000000..e1a7c54bdb
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/samples/transition-slide-hidden-parent/main.svelte
@@ -0,0 +1,13 @@
+<script>
+	import { slide } from 'svelte/transition';
+
+	let visible = $state(false);
+</script>
+
+<button onclick={() => (visible = !visible)}>toggle</button>
+
+<div style="display: none">
+	{#if visible}
+		<p transition:slide>hello</p>
+	{/if}
+</div>

From a6153f1d2a9168f8371149fbd775fa428c718a9b Mon Sep 17 00:00:00 2001
From: "svelte-triage-bot[bot]"
 <316883489+svelte-triage-bot[bot]@users.noreply.github.com>
Date: Fri, 21 Aug 2026 22:16:30 +0200
Subject: [PATCH 169/222] fix: preserve whitespace after inline elements when
 printing (#18685)

Fixes #18683.

The printer previously trimmed leading whitespace after an inline
element and failed to replace it when the fragment stayed on one line.
Track that whitespace while grouping fragment nodes and emit a space for
inline output, while retaining newline-based separation for multiline
output.

Adds regression coverage for whitespace following an inline element and
updates existing print snapshots that exposed the same behavior.
---
 .changeset/gentle-spaces-print.md             |  5 +++
 packages/svelte/src/compiler/print/index.js   | 37 +++++++++++--------
 .../tests/print/samples/comment/output.svelte |  2 +-
 .../samples/expression-tag/output.svelte      |  2 +-
 .../inline-element-whitespace/input.svelte    |  1 +
 .../inline-element-whitespace/output.svelte   |  1 +
 .../samples/regular-element/output.svelte     |  2 +-
 7 files changed, 31 insertions(+), 19 deletions(-)
 create mode 100644 .changeset/gentle-spaces-print.md
 create mode 100644 packages/svelte/tests/print/samples/inline-element-whitespace/input.svelte
 create mode 100644 packages/svelte/tests/print/samples/inline-element-whitespace/output.svelte

diff --git a/.changeset/gentle-spaces-print.md b/.changeset/gentle-spaces-print.md
new file mode 100644
index 0000000000..70b337fcd7
--- /dev/null
+++ b/.changeset/gentle-spaces-print.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: preserve whitespace after inline elements when printing
diff --git a/packages/svelte/src/compiler/print/index.js b/packages/svelte/src/compiler/print/index.js
index 4a78854e1e..554e788654 100644
--- a/packages/svelte/src/compiler/print/index.js
+++ b/packages/svelte/src/compiler/print/index.js
@@ -587,15 +587,19 @@ const svelte_visitors = (comments, state) => ({
 			last?.type === 'Text' &&
 			/\s$/.test(last.data);
 
-		/** @type {AST.SvelteNode[][]} */
+		/** @type {{ nodes: AST.SvelteNode[]; leading_whitespace: boolean }[]} */
 		const items = [];
 
 		/** @type {AST.SvelteNode[]} */
 		let sequence = [];
+		let leading_whitespace = false;
 
 		const flush = () => {
-			items.push(sequence);
-			sequence = [];
+			if (sequence.length > 0) {
+				items.push({ nodes: sequence, leading_whitespace });
+				sequence = [];
+				leading_whitespace = false;
+			}
 		};
 
 		for (let i = 0; i < node.nodes.length; i += 1) {
@@ -624,6 +628,7 @@ const svelte_visitors = (comments, state) => ({
 
 				if (child_node.data.startsWith(' ') && prev && prev.type !== 'ExpressionTag') {
 					flush();
+					leading_whitespace = true;
 					child_node.data = child_node.data.trimStart();
 				}
 
@@ -662,20 +667,18 @@ const svelte_visitors = (comments, state) => ({
 		let multiline = false;
 		let width = 0;
 
-		const child_contexts = items
-			.filter((x) => x.length > 0)
-			.map((sequence) => {
-				const child_context = context.new();
+		const child_contexts = items.map(({ nodes, leading_whitespace }) => {
+			const child_context = context.new();
 
-				for (const node of sequence) {
-					child_context.visit(node);
-					multiline ||= child_context.multiline;
-				}
+			for (const node of nodes) {
+				child_context.visit(node);
+				multiline ||= child_context.multiline;
+			}
 
-				width += child_context.measure();
+			width += child_context.measure() + (leading_whitespace ? 1 : 0);
 
-				return child_context;
-			});
+			return { context: child_context, leading_whitespace };
+		});
 
 		multiline ||= width > LINE_BREAK_THRESHOLD;
 		// Normally context.newline() also makes context.multiline true, but the below loop only
@@ -687,14 +690,16 @@ const svelte_visitors = (comments, state) => ({
 			const prev = child_contexts[i];
 			const next = child_contexts[i + 1];
 
-			context.append(prev);
+			context.append(prev.context);
 
 			if (next) {
-				if (prev.multiline || next.multiline) {
+				if (prev.context.multiline || next.context.multiline) {
 					context.margin();
 					context.newline();
 				} else if (multiline) {
 					context.newline();
+				} else if (next.leading_whitespace) {
+					context.write(' ');
 				}
 			}
 		}
diff --git a/packages/svelte/tests/print/samples/comment/output.svelte b/packages/svelte/tests/print/samples/comment/output.svelte
index f2f97b65be..2cac5f4048 100644
--- a/packages/svelte/tests/print/samples/comment/output.svelte
+++ b/packages/svelte/tests/print/samples/comment/output.svelte
@@ -1,3 +1,3 @@
-<!-- inline --><!-- 
+<!-- inline --> <!-- 
     multiline
 -->
diff --git a/packages/svelte/tests/print/samples/expression-tag/output.svelte b/packages/svelte/tests/print/samples/expression-tag/output.svelte
index 9142a59631..5af5746d87 100644
--- a/packages/svelte/tests/print/samples/expression-tag/output.svelte
+++ b/packages/svelte/tests/print/samples/expression-tag/output.svelte
@@ -1 +1 @@
-<span>{name}</span><span>{count + 1}</span>
+<span>{name}</span> <span>{count + 1}</span>
diff --git a/packages/svelte/tests/print/samples/inline-element-whitespace/input.svelte b/packages/svelte/tests/print/samples/inline-element-whitespace/input.svelte
new file mode 100644
index 0000000000..e442ae954c
--- /dev/null
+++ b/packages/svelte/tests/print/samples/inline-element-whitespace/input.svelte
@@ -0,0 +1 @@
+<p>Hello <strong>bold</strong> world</p>
diff --git a/packages/svelte/tests/print/samples/inline-element-whitespace/output.svelte b/packages/svelte/tests/print/samples/inline-element-whitespace/output.svelte
new file mode 100644
index 0000000000..e442ae954c
--- /dev/null
+++ b/packages/svelte/tests/print/samples/inline-element-whitespace/output.svelte
@@ -0,0 +1 @@
+<p>Hello <strong>bold</strong> world</p>
diff --git a/packages/svelte/tests/print/samples/regular-element/output.svelte b/packages/svelte/tests/print/samples/regular-element/output.svelte
index 0cf7c2472f..f5fd3c8f42 100644
--- a/packages/svelte/tests/print/samples/regular-element/output.svelte
+++ b/packages/svelte/tests/print/samples/regular-element/output.svelte
@@ -1 +1 @@
-<div><a href="/foo">bar</a></div><br />
+<div><a href="/foo">bar</a></div> <br />

From 78979c87c96e6071502e8111a2fc5f312ad586b8 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 21 Aug 2026 22:24:11 +0200
Subject: [PATCH 170/222] chore(deps-dev): bump vite from 7.3.2 to 7.3.5
 (#18444)

---
 playgrounds/sandbox/package.json |   2 +-
 pnpm-lock.yaml                   | 366 ++++++++++++++++++++++++++-----
 2 files changed, 315 insertions(+), 53 deletions(-)

diff --git a/playgrounds/sandbox/package.json b/playgrounds/sandbox/package.json
index 12676777cb..bb7f5f0c81 100644
--- a/playgrounds/sandbox/package.json
+++ b/playgrounds/sandbox/package.json
@@ -21,7 +21,7 @@
     "polka": "^1.0.0-next.25",
     "svelte": "workspace:*",
     "tinyglobby": "^0.2.12",
-    "vite": "^7.3.2",
+    "vite": "^7.3.5",
     "vite-plugin-devtools-json": "^1.0.0",
     "vite-plugin-inspect": "^11.3.3"
   }
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 095d166118..70dcf70e5b 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -64,7 +64,7 @@ importers:
         version: 1.2.5
       vitest:
         specifier: ^4.1.7
-        version: 4.1.7(@types/node@20.19.17)(@vitest/coverage-v8@4.1.7)(jsdom@25.0.1)(vite@7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+        version: 4.1.7(@types/node@20.19.17)(@vitest/coverage-v8@4.1.7)(jsdom@25.0.1)(vite@7.3.5(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
 
   packages/svelte:
     dependencies:
@@ -164,7 +164,7 @@ importers:
         version: 5.5.4
       vitest:
         specifier: ^4.1.7
-        version: 4.1.7(@types/node@20.19.17)(@vitest/coverage-v8@4.1.7)(jsdom@25.0.1)(vite@7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+        version: 4.1.7(@types/node@20.19.17)(@vitest/coverage-v8@4.1.7)(jsdom@25.0.1)(vite@7.3.5(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
       web-features:
         specifier: ^3.29.0
         version: 3.29.0
@@ -173,7 +173,7 @@ importers:
     devDependencies:
       '@sveltejs/vite-plugin-svelte':
         specifier: ^6.2.0
-        version: 6.2.0(svelte@packages+svelte)(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+        version: 6.2.0(svelte@packages+svelte)(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
       '@types/node':
         specifier: ^24.5.2
         version: 24.5.2
@@ -187,14 +187,14 @@ importers:
         specifier: ^0.2.12
         version: 0.2.15
       vite:
-        specifier: ^7.3.2
-        version: 7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+        specifier: ^7.3.5
+        version: 7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
       vite-plugin-devtools-json:
         specifier: ^1.0.0
-        version: 1.0.0(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+        version: 1.0.0(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
       vite-plugin-inspect:
         specifier: ^11.3.3
-        version: 11.3.3(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+        version: 11.3.3(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
 
 packages:
 
@@ -781,126 +781,251 @@ packages:
     cpu: [arm]
     os: [android]
 
+  '@rollup/rollup-android-arm-eabi@4.62.2':
+    resolution: {integrity: sha512-6o7ZLZK+BeenkZCFNDXqpbjw9bD6nuWonvS/lwQJp7NoVVxm6p3qE7qQ5jGuBjiFsgvqjD8mZAU5oWxTmbOeOg==}
+    cpu: [arm]
+    os: [android]
+
   '@rollup/rollup-android-arm64@4.60.1':
     resolution: {integrity: sha512-YjG/EwIDvvYI1YvYbHvDz/BYHtkY4ygUIXHnTdLhG+hKIQFBiosfWiACWortsKPKU/+dUwQQCKQM3qrDe8c9BA==}
     cpu: [arm64]
     os: [android]
 
+  '@rollup/rollup-android-arm64@4.62.2':
+    resolution: {integrity: sha512-BaH7BllCACHoH1LguOU56UItGfUWjujlO65kS9LAodViaN4bwIKd7oeW/ZHJ/4ljr/7MIiENnNy3HJ0zXv8Zkw==}
+    cpu: [arm64]
+    os: [android]
+
   '@rollup/rollup-darwin-arm64@4.60.1':
     resolution: {integrity: sha512-mjCpF7GmkRtSJwon+Rq1N8+pI+8l7w5g9Z3vWj4T7abguC4Czwi3Yu/pFaLvA3TTeMVjnu3ctigusqWUfjZzvw==}
     cpu: [arm64]
     os: [darwin]
 
+  '@rollup/rollup-darwin-arm64@4.62.2':
+    resolution: {integrity: sha512-v39RCCvj4He82I9sFmk+M1VZ0PLM9sfsLVikjfx2hYBNALhrrOR2D3JjQA6AhlaSOgcR+RzrKY7e1+bT6SUO/A==}
+    cpu: [arm64]
+    os: [darwin]
+
   '@rollup/rollup-darwin-x64@4.60.1':
     resolution: {integrity: sha512-haZ7hJ1JT4e9hqkoT9R/19XW2QKqjfJVv+i5AGg57S+nLk9lQnJ1F/eZloRO3o9Scy9CM3wQ9l+dkXtcBgN5Ew==}
     cpu: [x64]
     os: [darwin]
 
+  '@rollup/rollup-darwin-x64@4.62.2':
+    resolution: {integrity: sha512-yl0y2vq3S3lHeuXhEdss6TWfKW8vkujImO12tn4ZkG/4oghr09LvdYm2RElVjokTQiUvDUGXLGsYeLqUMCKpGA==}
+    cpu: [x64]
+    os: [darwin]
+
   '@rollup/rollup-freebsd-arm64@4.60.1':
     resolution: {integrity: sha512-czw90wpQq3ZsAVBlinZjAYTKduOjTywlG7fEeWKUA7oCmpA8xdTkxZZlwNJKWqILlq0wehoZcJYfBvOyhPTQ6w==}
     cpu: [arm64]
     os: [freebsd]
 
+  '@rollup/rollup-freebsd-arm64@4.62.2':
+    resolution: {integrity: sha512-tT4pvt4qXD+vEoezupCWi+a1F0vvDiksiHc+PxRlYTOH1I6/X4id9jPxTP+Fg+545euaFT1jJVs4CEdHZAU1vw==}
+    cpu: [arm64]
+    os: [freebsd]
+
   '@rollup/rollup-freebsd-x64@4.60.1':
     resolution: {integrity: sha512-KVB2rqsxTHuBtfOeySEyzEOB7ltlB/ux38iu2rBQzkjbwRVlkhAGIEDiiYnO2kFOkJp+Z7pUXKyrRRFuFUKt+g==}
     cpu: [x64]
     os: [freebsd]
 
+  '@rollup/rollup-freebsd-x64@4.62.2':
+    resolution: {integrity: sha512-6nU5F2wCW+qvCBhTn1pdIU3bzsIoF7EUwsCDRxilWGprQR6yd508YnH9+OKFCwpfS8pjZqDUmnCAr7exax0XCg==}
+    cpu: [x64]
+    os: [freebsd]
+
   '@rollup/rollup-linux-arm-gnueabihf@4.60.1':
     resolution: {integrity: sha512-L+34Qqil+v5uC0zEubW7uByo78WOCIrBvci69E7sFASRl0X7b/MB6Cqd1lky/CtcSVTydWa2WZwFuWexjS5o6g==}
     cpu: [arm]
     os: [linux]
 
+  '@rollup/rollup-linux-arm-gnueabihf@4.62.2':
+    resolution: {integrity: sha512-n1GJHPOvpIfhi3TmrCeh6S6URt9BFCt0KQE3qvexyGCTAKpR4Lg+eWvNZEqu7epxwus/8ElT3hacYEucm49SZg==}
+    cpu: [arm]
+    os: [linux]
+
   '@rollup/rollup-linux-arm-musleabihf@4.60.1':
     resolution: {integrity: sha512-n83O8rt4v34hgFzlkb1ycniJh7IR5RCIqt6mz1VRJD6pmhRi0CXdmfnLu9dIUS6buzh60IvACM842Ffb3xd6Gg==}
     cpu: [arm]
     os: [linux]
 
+  '@rollup/rollup-linux-arm-musleabihf@4.62.2':
+    resolution: {integrity: sha512-JqgflS8wEB+UXV/vS1RpRbifGBeN4D5lz8D8oOFbFZw4vedvdOgCFAjfBmIMdW3yL10XpQQ0Ambepw6MXrhOnA==}
+    cpu: [arm]
+    os: [linux]
+
   '@rollup/rollup-linux-arm64-gnu@4.60.1':
     resolution: {integrity: sha512-Nql7sTeAzhTAja3QXeAI48+/+GjBJ+QmAH13snn0AJSNL50JsDqotyudHyMbO2RbJkskbMbFJfIJKWA6R1LCJQ==}
     cpu: [arm64]
     os: [linux]
 
+  '@rollup/rollup-linux-arm64-gnu@4.62.2':
+    resolution: {integrity: sha512-wnFJkogWvN4jm/hQRF2UBaeUmk20j5+DmHvoyWii2b8HJDyvz1MF2OU/6ynXt2KR63rbZLWkFpoytpdc/yBuSA==}
+    cpu: [arm64]
+    os: [linux]
+
   '@rollup/rollup-linux-arm64-musl@4.60.1':
     resolution: {integrity: sha512-+pUymDhd0ys9GcKZPPWlFiZ67sTWV5UU6zOJat02M1+PiuSGDziyRuI/pPue3hoUwm2uGfxdL+trT6Z9rxnlMA==}
     cpu: [arm64]
     os: [linux]
 
+  '@rollup/rollup-linux-arm64-musl@4.62.2':
+    resolution: {integrity: sha512-HVu2bp0zhvJ8xHEV9+UUs7S90VadmBSY3LcIMvozbPo4AuMGDWlz3ymHLHZPX4hR67TKTt8Qp5PJ5RBg/i+RMQ==}
+    cpu: [arm64]
+    os: [linux]
+
   '@rollup/rollup-linux-loong64-gnu@4.60.1':
     resolution: {integrity: sha512-VSvgvQeIcsEvY4bKDHEDWcpW4Yw7BtlKG1GUT4FzBUlEKQK0rWHYBqQt6Fm2taXS+1bXvJT6kICu5ZwqKCnvlQ==}
     cpu: [loong64]
     os: [linux]
 
+  '@rollup/rollup-linux-loong64-gnu@4.62.2':
+    resolution: {integrity: sha512-mQqqAV8QaoSgr9I2fKDLY2BAVvmKjWoGiu/cSYQonsLvtqwEn1E4QYfnCOcp5zoEqNhsDYin1s6jx/VJmrxlZg==}
+    cpu: [loong64]
+    os: [linux]
+
   '@rollup/rollup-linux-loong64-musl@4.60.1':
     resolution: {integrity: sha512-4LqhUomJqwe641gsPp6xLfhqWMbQV04KtPp7/dIp0nzPxAkNY1AbwL5W0MQpcalLYk07vaW9Kp1PBhdpZYYcEw==}
     cpu: [loong64]
     os: [linux]
 
+  '@rollup/rollup-linux-loong64-musl@4.62.2':
+    resolution: {integrity: sha512-IxKLoxCQ2IWi6bT2akyDUBGsOImDKB+sPp4EsTmwFQ/fMwpCKm8uLSSgP/Kx/QYUgKis6SEZ5/Nlhup0DIA0PQ==}
+    cpu: [loong64]
+    os: [linux]
+
   '@rollup/rollup-linux-ppc64-gnu@4.60.1':
     resolution: {integrity: sha512-tLQQ9aPvkBxOc/EUT6j3pyeMD6Hb8QF2BTBnCQWP/uu1lhc9AIrIjKnLYMEroIz/JvtGYgI9dF3AxHZNaEH0rw==}
     cpu: [ppc64]
     os: [linux]
 
+  '@rollup/rollup-linux-ppc64-gnu@4.62.2':
+    resolution: {integrity: sha512-Mk5ha2RQSgyFfmYYLkBpPnUk8D8FriBxesO1u9O75X0mHgXL1UQcH5Itl2lurWL2tj0RxV9b9tJgipac0hRY9A==}
+    cpu: [ppc64]
+    os: [linux]
+
   '@rollup/rollup-linux-ppc64-musl@4.60.1':
     resolution: {integrity: sha512-RMxFhJwc9fSXP6PqmAz4cbv3kAyvD1etJFjTx4ONqFP9DkTkXsAMU4v3Vyc5BgzC+anz7nS/9tp4obsKfqkDHg==}
     cpu: [ppc64]
     os: [linux]
 
+  '@rollup/rollup-linux-ppc64-musl@4.62.2':
+    resolution: {integrity: sha512-CjvEnqJL/0/TQ3TXX3OPIJ/kmBellrWd4heXUmHeJlTnmwjKpSJzoehLaL6Xk0ZnMHBu9dZuFADNOrtjF4v+2w==}
+    cpu: [ppc64]
+    os: [linux]
+
   '@rollup/rollup-linux-riscv64-gnu@4.60.1':
     resolution: {integrity: sha512-QKgFl+Yc1eEk6MmOBfRHYF6lTxiiiV3/z/BRrbSiW2I7AFTXoBFvdMEyglohPj//2mZS4hDOqeB0H1ACh3sBbg==}
     cpu: [riscv64]
     os: [linux]
 
+  '@rollup/rollup-linux-riscv64-gnu@4.62.2':
+    resolution: {integrity: sha512-1SiZbzwdkaDURsew/tSOrooKiYy7EQGT6m8ufavAi9NEyQb/6VuIxFXAL1fqa4iZe3g4NbNk4P7J32z2tw5Mgg==}
+    cpu: [riscv64]
+    os: [linux]
+
   '@rollup/rollup-linux-riscv64-musl@4.60.1':
     resolution: {integrity: sha512-RAjXjP/8c6ZtzatZcA1RaQr6O1TRhzC+adn8YZDnChliZHviqIjmvFwHcxi4JKPSDAt6Uhf/7vqcBzQJy0PDJg==}
     cpu: [riscv64]
     os: [linux]
 
+  '@rollup/rollup-linux-riscv64-musl@4.62.2':
+    resolution: {integrity: sha512-nQts12zJ3NQRoE6uYljOH89v7szzLDvG2JD/vsX+vGXU8w/At1GowTZ5/7qeFQ8m7L55rpR8Okugnuo5bgjy2Q==}
+    cpu: [riscv64]
+    os: [linux]
+
   '@rollup/rollup-linux-s390x-gnu@4.60.1':
     resolution: {integrity: sha512-wcuocpaOlaL1COBYiA89O6yfjlp3RwKDeTIA0hM7OpmhR1Bjo9j31G1uQVpDlTvwxGn2nQs65fBFL5UFd76FcQ==}
     cpu: [s390x]
     os: [linux]
 
+  '@rollup/rollup-linux-s390x-gnu@4.62.2':
+    resolution: {integrity: sha512-E9/ll019jhPIJgpzfZoIkBGhcz+kKNgVWYRY0zr9srBdPPFVpvOKW8VaJKUbeK+eZXyQF9ltME+Kk6affeaPgg==}
+    cpu: [s390x]
+    os: [linux]
+
   '@rollup/rollup-linux-x64-gnu@4.60.1':
     resolution: {integrity: sha512-77PpsFQUCOiZR9+LQEFg9GClyfkNXj1MP6wRnzYs0EeWbPcHs02AXu4xuUbM1zhwn3wqaizle3AEYg5aeoohhg==}
     cpu: [x64]
     os: [linux]
 
+  '@rollup/rollup-linux-x64-gnu@4.62.2':
+    resolution: {integrity: sha512-5BqxR/pshjey51iliyzTD5Xi3EN0aLmQ2lZ3lvefVV9c82BvrLo2/6OT55iifpWBufs6kdwWbuOKS841DrmK9A==}
+    cpu: [x64]
+    os: [linux]
+
   '@rollup/rollup-linux-x64-musl@4.60.1':
     resolution: {integrity: sha512-5cIATbk5vynAjqqmyBjlciMJl1+R/CwX9oLk/EyiFXDWd95KpHdrOJT//rnUl4cUcskrd0jCCw3wpZnhIHdD9w==}
     cpu: [x64]
     os: [linux]
 
+  '@rollup/rollup-linux-x64-musl@4.62.2':
+    resolution: {integrity: sha512-uNN83XxQrRAh/w0/pmAfibcwyb6YWt4gP+dpnQKPVJshAloQ785ii8CT8ZCIxkGg9opVsvAlGhFitSm6D1Jjpg==}
+    cpu: [x64]
+    os: [linux]
+
   '@rollup/rollup-openbsd-x64@4.60.1':
     resolution: {integrity: sha512-cl0w09WsCi17mcmWqqglez9Gk8isgeWvoUZ3WiJFYSR3zjBQc2J5/ihSjpl+VLjPqjQ/1hJRcqBfLjssREQILw==}
     cpu: [x64]
     os: [openbsd]
 
+  '@rollup/rollup-openbsd-x64@4.62.2':
+    resolution: {integrity: sha512-srjEIxSH3LRnJN6THczDHWQplqEMFiAJrTab0msUryh9kwNpkICf3Ea6q6MN/2cZwRFUNx5w+h6Hpi4QuHS6Zg==}
+    cpu: [x64]
+    os: [openbsd]
+
   '@rollup/rollup-openharmony-arm64@4.60.1':
     resolution: {integrity: sha512-4Cv23ZrONRbNtbZa37mLSueXUCtN7MXccChtKpUnQNgF010rjrjfHx3QxkS2PI7LqGT5xXyYs1a7LbzAwT0iCA==}
     cpu: [arm64]
     os: [openharmony]
 
+  '@rollup/rollup-openharmony-arm64@4.62.2':
+    resolution: {integrity: sha512-8hOJnxgbyObnCm5AlRA3A931xX19xq80RjVTKgJOvEKWqJruP/Uf12IbAOaDjjEXYRewwHLfmF0YRIdK3OwKWA==}
+    cpu: [arm64]
+    os: [openharmony]
+
   '@rollup/rollup-win32-arm64-msvc@4.60.1':
     resolution: {integrity: sha512-i1okWYkA4FJICtr7KpYzFpRTHgy5jdDbZiWfvny21iIKky5YExiDXP+zbXzm3dUcFpkEeYNHgQ5fuG236JPq0g==}
     cpu: [arm64]
     os: [win32]
 
+  '@rollup/rollup-win32-arm64-msvc@4.62.2':
+    resolution: {integrity: sha512-mmF4AY1i0hG/bLWUctUq59gtmgaSIRa3cu/A3JFRp/sCNEme2bgDEiDS22P9FbnJB8NJNF4jPJiSP5RHQpUTDg==}
+    cpu: [arm64]
+    os: [win32]
+
   '@rollup/rollup-win32-ia32-msvc@4.60.1':
     resolution: {integrity: sha512-u09m3CuwLzShA0EYKMNiFgcjjzwqtUMLmuCJLeZWjjOYA3IT2Di09KaxGBTP9xVztWyIWjVdsB2E9goMjZvTQg==}
     cpu: [ia32]
     os: [win32]
 
+  '@rollup/rollup-win32-ia32-msvc@4.62.2':
+    resolution: {integrity: sha512-DZgkknc6jhHrk46V25vbAM0zZkyP0nSDkJB8/dRkLTxv470dOmWDqGoEJl/9A0dFfS7yE3REOwNDxpHwSLSt0Q==}
+    cpu: [ia32]
+    os: [win32]
+
   '@rollup/rollup-win32-x64-gnu@4.60.1':
     resolution: {integrity: sha512-k+600V9Zl1CM7eZxJgMyTUzmrmhB/0XZnF4pRypKAlAgxmedUA+1v9R+XOFv56W4SlHEzfeMtzujLJD22Uz5zg==}
     cpu: [x64]
     os: [win32]
 
+  '@rollup/rollup-win32-x64-gnu@4.62.2':
+    resolution: {integrity: sha512-T6xr6ucWSFto+VGajA8YH26LdpHRuP4YLHEKAtCWvJDOlnmWcDZVCI2Jmjr+IFHDlt2zRaTAKE4tfjTaWLgJBg==}
+    cpu: [x64]
+    os: [win32]
+
   '@rollup/rollup-win32-x64-msvc@4.60.1':
     resolution: {integrity: sha512-lWMnixq/QzxyhTV6NjQJ4SFo1J6PvOX8vUx5Wb4bBPsEb+8xZ89Bz6kOXpfXj9ak9AHTQVQzlgzBEc1SyM27xQ==}
     cpu: [x64]
     os: [win32]
 
+  '@rollup/rollup-win32-x64-msvc@4.62.2':
+    resolution: {integrity: sha512-BfzEnDJOt9T8M989/lA37EcJgat01wLRnoi5dQf3QzOH7jzpqTAzdDbVfRljVr5r+jzKqpbHeyOfAaXxAd0PAA==}
+    cpu: [x64]
+    os: [win32]
+
   '@standard-schema/spec@1.1.0':
     resolution: {integrity: sha512-l2aFy5jALhniG5HgqrD6jXLi/rUWrKvqN/qJx6yoJsgKhblVd+iqqU4RCXavm/jPityDo5TCvKMnpjKnOriy0w==}
 
@@ -1850,6 +1975,11 @@ packages:
     engines: {node: ^10 || ^12 || ^13.7 || ^14 || >=15.0.1}
     hasBin: true
 
+  nanoid@3.3.13:
+    resolution: {integrity: sha512-sPdqC6ByMVVGvF1ynvvMo0/o+oD1VX7DaHhijt1bFgjvBkHBib4t49GoNDhf2NDta4oeUNlaGbSt5K7qjZ955Q==}
+    engines: {node: ^10 || ^12 || ^13.7 || ^14 || >=15.0.1}
+    hasBin: true
+
   natural-compare@1.4.0:
     resolution: {integrity: sha512-OWND8ei3VtNC9h7V60qff3SVobHr996CTwgxubgyQYEpg290h9J0buyECNNJexkFm5sOajh5G116RYA1c8ZMSw==}
 
@@ -1989,6 +2119,10 @@ packages:
     resolution: {integrity: sha512-8sLjZwK0R+JlxlYcTuVnyT2v+htpdrjDOKuMcOVdYjt52Lh8hWRYpxBPoKx/Zg+bcjc3wx6fmQevMmUztS/ccA==}
     engines: {node: '>=4'}
 
+  postcss@8.5.15:
+    resolution: {integrity: sha512-FfR8sjd4em2T6fb3I2MwAJU7HWVMr9zba+enmQeeWFfCbm+UOC/0X4DS8XtpUTMwWMGbjKYP7xjfNekzyGmB3A==}
+    engines: {node: ^10 || ^12 || >=14}
+
   postcss@8.5.9:
     resolution: {integrity: sha512-7a70Nsot+EMX9fFU3064K/kdHWZqGVY+BADLyXc8Dfv+mTLLVl6JzJpPaCZ2kQL9gIJvKXSLMHhqdRRjwQeFtw==}
     engines: {node: ^10 || ^12 || >=14}
@@ -2058,6 +2192,11 @@ packages:
     engines: {node: '>=18.0.0', npm: '>=8.0.0'}
     hasBin: true
 
+  rollup@4.62.2:
+    resolution: {integrity: sha512-RFnrW4lhXA3s3eqHDZvN654g8OTjzRfqpIRJYczCGB6HzphckVAi/Qh4tbPUbRuDi7s1Llv8g/NspLkttY3gTA==}
+    engines: {node: '>=18.0.0', npm: '>=8.0.0'}
+    hasBin: true
+
   rrweb-cssom@0.7.1:
     resolution: {integrity: sha512-TrEMa7JGdVm0UThDJSx7ddw5nVm3UJS9o9CCIZ72B1vSyEZoziDqBYP3XIoi/12lKrJR8rE3jeFHMok2F/Mnsg==}
 
@@ -2092,8 +2231,8 @@ packages:
     engines: {node: '>=10'}
     hasBin: true
 
-  semver@7.8.4:
-    resolution: {integrity: sha512-rUCObTnP32Q08R2uuIrt7r9PlEonuTmtuXYcW6s5kjdlj3xbnwe+21yXptAUYcMAABLkYYTtnmzb3w3EDZfueA==}
+  semver@7.8.5:
+    resolution: {integrity: sha512-Y7/KDsb8LjooZpwaqGyulO6DQlksgCncchHGk+sZIY4SBvUocMBEFH5Ur1fI4dV+Jvl0w6cjvucaIi40puRioA==}
     engines: {node: '>=10'}
     hasBin: true
 
@@ -2205,6 +2344,10 @@ packages:
     resolution: {integrity: sha512-j2Zq4NyQYG5XMST4cbs02Ak8iJUdxRM0XI5QyxXuZOzKOINmWurp3smXu3y5wDcJrptwpSjgXHzIQxR0omXljQ==}
     engines: {node: '>=12.0.0'}
 
+  tinyglobby@0.2.17:
+    resolution: {integrity: sha512-wXR/dYpcqKmfWpEdZjiKJOwCNFndD0DMnrW/cYjVGttEkBfVgcLFHoNrlj47mjOVic9yyNu65alsgF4NQyTa2g==}
+    engines: {node: '>=12.0.0'}
+
   tinyrainbow@3.1.0:
     resolution: {integrity: sha512-Bf+ILmBgretUrdJxzXM0SgXLZ3XfiaUuOj/IKQHuTXip+05Xn+uyEYdVg0kYDipTBcLrCVyUzAPz7QmArb0mmw==}
     engines: {node: '>=14.0.0'}
@@ -2322,8 +2465,8 @@ packages:
       '@nuxt/kit':
         optional: true
 
-  vite@7.3.2:
-    resolution: {integrity: sha512-Bby3NOsna2jsjfLVOHKes8sGwgl4TT0E6vvpYgnAYDIF/tie7MRaFthmKuHx1NSXjiTueXH3do80FMQgvEktRg==}
+  vite@7.3.5:
+    resolution: {integrity: sha512-KuOaNhcnGFN2zIPGA7wRmzF+lJA1sea7rHq17aiJ++9lzY1WWG6Jpwqwe1KNbRVPIqHmr8GLYx7jbrQcN/7/ww==}
     engines: {node: ^20.19.0 || >=22.12.0}
     hasBin: true
     peerDependencies:
@@ -2977,78 +3120,153 @@ snapshots:
   '@rollup/rollup-android-arm-eabi@4.60.1':
     optional: true
 
+  '@rollup/rollup-android-arm-eabi@4.62.2':
+    optional: true
+
   '@rollup/rollup-android-arm64@4.60.1':
     optional: true
 
+  '@rollup/rollup-android-arm64@4.62.2':
+    optional: true
+
   '@rollup/rollup-darwin-arm64@4.60.1':
     optional: true
 
+  '@rollup/rollup-darwin-arm64@4.62.2':
+    optional: true
+
   '@rollup/rollup-darwin-x64@4.60.1':
     optional: true
 
+  '@rollup/rollup-darwin-x64@4.62.2':
+    optional: true
+
   '@rollup/rollup-freebsd-arm64@4.60.1':
     optional: true
 
+  '@rollup/rollup-freebsd-arm64@4.62.2':
+    optional: true
+
   '@rollup/rollup-freebsd-x64@4.60.1':
     optional: true
 
+  '@rollup/rollup-freebsd-x64@4.62.2':
+    optional: true
+
   '@rollup/rollup-linux-arm-gnueabihf@4.60.1':
     optional: true
 
+  '@rollup/rollup-linux-arm-gnueabihf@4.62.2':
+    optional: true
+
   '@rollup/rollup-linux-arm-musleabihf@4.60.1':
     optional: true
 
+  '@rollup/rollup-linux-arm-musleabihf@4.62.2':
+    optional: true
+
   '@rollup/rollup-linux-arm64-gnu@4.60.1':
     optional: true
 
+  '@rollup/rollup-linux-arm64-gnu@4.62.2':
+    optional: true
+
   '@rollup/rollup-linux-arm64-musl@4.60.1':
     optional: true
 
+  '@rollup/rollup-linux-arm64-musl@4.62.2':
+    optional: true
+
   '@rollup/rollup-linux-loong64-gnu@4.60.1':
     optional: true
 
+  '@rollup/rollup-linux-loong64-gnu@4.62.2':
+    optional: true
+
   '@rollup/rollup-linux-loong64-musl@4.60.1':
     optional: true
 
+  '@rollup/rollup-linux-loong64-musl@4.62.2':
+    optional: true
+
   '@rollup/rollup-linux-ppc64-gnu@4.60.1':
     optional: true
 
+  '@rollup/rollup-linux-ppc64-gnu@4.62.2':
+    optional: true
+
   '@rollup/rollup-linux-ppc64-musl@4.60.1':
     optional: true
 
+  '@rollup/rollup-linux-ppc64-musl@4.62.2':
+    optional: true
+
   '@rollup/rollup-linux-riscv64-gnu@4.60.1':
     optional: true
 
+  '@rollup/rollup-linux-riscv64-gnu@4.62.2':
+    optional: true
+
   '@rollup/rollup-linux-riscv64-musl@4.60.1':
     optional: true
 
+  '@rollup/rollup-linux-riscv64-musl@4.62.2':
+    optional: true
+
   '@rollup/rollup-linux-s390x-gnu@4.60.1':
     optional: true
 
+  '@rollup/rollup-linux-s390x-gnu@4.62.2':
+    optional: true
+
   '@rollup/rollup-linux-x64-gnu@4.60.1':
     optional: true
 
+  '@rollup/rollup-linux-x64-gnu@4.62.2':
+    optional: true
+
   '@rollup/rollup-linux-x64-musl@4.60.1':
     optional: true
 
+  '@rollup/rollup-linux-x64-musl@4.62.2':
+    optional: true
+
   '@rollup/rollup-openbsd-x64@4.60.1':
     optional: true
 
+  '@rollup/rollup-openbsd-x64@4.62.2':
+    optional: true
+
   '@rollup/rollup-openharmony-arm64@4.60.1':
     optional: true
 
+  '@rollup/rollup-openharmony-arm64@4.62.2':
+    optional: true
+
   '@rollup/rollup-win32-arm64-msvc@4.60.1':
     optional: true
 
+  '@rollup/rollup-win32-arm64-msvc@4.62.2':
+    optional: true
+
   '@rollup/rollup-win32-ia32-msvc@4.60.1':
     optional: true
 
+  '@rollup/rollup-win32-ia32-msvc@4.62.2':
+    optional: true
+
   '@rollup/rollup-win32-x64-gnu@4.60.1':
     optional: true
 
+  '@rollup/rollup-win32-x64-gnu@4.62.2':
+    optional: true
+
   '@rollup/rollup-win32-x64-msvc@4.60.1':
     optional: true
 
+  '@rollup/rollup-win32-x64-msvc@4.62.2':
+    optional: true
+
   '@standard-schema/spec@1.1.0': {}
 
   '@stylistic/eslint-plugin-js@1.8.0(eslint@10.0.0)':
@@ -3076,24 +3294,24 @@ snapshots:
       typescript: 5.5.4
       typescript-eslint: 8.56.0(eslint@10.0.0)(typescript@5.5.4)
 
-  '@sveltejs/vite-plugin-svelte-inspector@5.0.1(@sveltejs/vite-plugin-svelte@6.2.0(svelte@packages+svelte)(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)))(svelte@packages+svelte)(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))':
+  '@sveltejs/vite-plugin-svelte-inspector@5.0.1(@sveltejs/vite-plugin-svelte@6.2.0(svelte@packages+svelte)(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)))(svelte@packages+svelte)(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))':
     dependencies:
-      '@sveltejs/vite-plugin-svelte': 6.2.0(svelte@packages+svelte)(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+      '@sveltejs/vite-plugin-svelte': 6.2.0(svelte@packages+svelte)(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
       debug: 4.4.3
       svelte: link:packages/svelte
-      vite: 7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+      vite: 7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
     transitivePeerDependencies:
       - supports-color
 
-  '@sveltejs/vite-plugin-svelte@6.2.0(svelte@packages+svelte)(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))':
+  '@sveltejs/vite-plugin-svelte@6.2.0(svelte@packages+svelte)(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))':
     dependencies:
-      '@sveltejs/vite-plugin-svelte-inspector': 5.0.1(@sveltejs/vite-plugin-svelte@6.2.0(svelte@packages+svelte)(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)))(svelte@packages+svelte)(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+      '@sveltejs/vite-plugin-svelte-inspector': 5.0.1(@sveltejs/vite-plugin-svelte@6.2.0(svelte@packages+svelte)(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)))(svelte@packages+svelte)(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
       debug: 4.4.3
       deepmerge: 4.3.1
       magic-string: 0.30.17
       svelte: link:packages/svelte
-      vite: 7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
-      vitefu: 1.1.1(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+      vite: 7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+      vitefu: 1.1.1(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
     transitivePeerDependencies:
       - supports-color
 
@@ -3207,7 +3425,7 @@ snapshots:
       debug: 4.4.3
       minimatch: 9.0.5
       semver: 7.7.4
-      tinyglobby: 0.2.15
+      tinyglobby: 0.2.17
       ts-api-utils: 2.4.0(typescript@5.5.4)
       typescript: 5.5.4
     transitivePeerDependencies:
@@ -3241,7 +3459,7 @@ snapshots:
       obug: 2.1.1
       std-env: 4.1.0
       tinyrainbow: 3.1.0
-      vitest: 4.1.7(@types/node@20.19.17)(@vitest/coverage-v8@4.1.7)(jsdom@25.0.1)(vite@7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+      vitest: 4.1.7(@types/node@20.19.17)(@vitest/coverage-v8@4.1.7)(jsdom@25.0.1)(vite@7.3.5(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
 
   '@vitest/expect@4.1.7':
     dependencies:
@@ -3252,13 +3470,13 @@ snapshots:
       chai: 6.2.2
       tinyrainbow: 3.1.0
 
-  '@vitest/mocker@4.1.7(vite@7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))':
+  '@vitest/mocker@4.1.7(vite@7.3.5(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))':
     dependencies:
       '@vitest/spy': 4.1.7
       estree-walker: 3.0.3
       magic-string: 0.30.21
     optionalDependencies:
-      vite: 7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+      vite: 7.3.5(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
 
   '@vitest/pretty-format@4.1.7':
     dependencies:
@@ -3543,7 +3761,7 @@ snapshots:
   eslint-compat-utils@0.5.1(eslint@10.0.0):
     dependencies:
       eslint: 10.0.0
-      semver: 7.8.4
+      semver: 7.8.5
 
   eslint-config-prettier@9.1.0(eslint@10.0.0):
     dependencies:
@@ -3570,7 +3788,7 @@ snapshots:
       globals: 15.15.0
       globrex: 0.1.2
       ignore: 5.3.2
-      semver: 7.8.4
+      semver: 7.8.5
       ts-declaration-location: 1.0.7(typescript@5.5.4)
     transitivePeerDependencies:
       - typescript
@@ -4070,6 +4288,8 @@ snapshots:
 
   nanoid@3.3.11: {}
 
+  nanoid@3.3.13: {}
+
   natural-compare@1.4.0: {}
 
   normalize-path@3.0.0:
@@ -4175,15 +4395,21 @@ snapshots:
     dependencies:
       postcss: 8.5.9
 
-  postcss-scss@4.0.9(postcss@8.5.9):
+  postcss-scss@4.0.9(postcss@8.5.15):
     dependencies:
-      postcss: 8.5.9
+      postcss: 8.5.15
 
   postcss-selector-parser@7.1.0:
     dependencies:
       cssesc: 3.0.0
       util-deprecate: 1.0.2
 
+  postcss@8.5.15:
+    dependencies:
+      nanoid: 3.3.13
+      picocolors: 1.1.1
+      source-map-js: 1.2.1
+
   postcss@8.5.9:
     dependencies:
       nanoid: 3.3.11
@@ -4268,6 +4494,37 @@ snapshots:
       '@rollup/rollup-win32-x64-msvc': 4.60.1
       fsevents: 2.3.3
 
+  rollup@4.62.2:
+    dependencies:
+      '@types/estree': 1.0.9
+    optionalDependencies:
+      '@rollup/rollup-android-arm-eabi': 4.62.2
+      '@rollup/rollup-android-arm64': 4.62.2
+      '@rollup/rollup-darwin-arm64': 4.62.2
+      '@rollup/rollup-darwin-x64': 4.62.2
+      '@rollup/rollup-freebsd-arm64': 4.62.2
+      '@rollup/rollup-freebsd-x64': 4.62.2
+      '@rollup/rollup-linux-arm-gnueabihf': 4.62.2
+      '@rollup/rollup-linux-arm-musleabihf': 4.62.2
+      '@rollup/rollup-linux-arm64-gnu': 4.62.2
+      '@rollup/rollup-linux-arm64-musl': 4.62.2
+      '@rollup/rollup-linux-loong64-gnu': 4.62.2
+      '@rollup/rollup-linux-loong64-musl': 4.62.2
+      '@rollup/rollup-linux-ppc64-gnu': 4.62.2
+      '@rollup/rollup-linux-ppc64-musl': 4.62.2
+      '@rollup/rollup-linux-riscv64-gnu': 4.62.2
+      '@rollup/rollup-linux-riscv64-musl': 4.62.2
+      '@rollup/rollup-linux-s390x-gnu': 4.62.2
+      '@rollup/rollup-linux-x64-gnu': 4.62.2
+      '@rollup/rollup-linux-x64-musl': 4.62.2
+      '@rollup/rollup-openbsd-x64': 4.62.2
+      '@rollup/rollup-openharmony-arm64': 4.62.2
+      '@rollup/rollup-win32-arm64-msvc': 4.62.2
+      '@rollup/rollup-win32-ia32-msvc': 4.62.2
+      '@rollup/rollup-win32-x64-gnu': 4.62.2
+      '@rollup/rollup-win32-x64-msvc': 4.62.2
+      fsevents: 2.3.3
+
   rrweb-cssom@0.7.1: {}
 
   run-applescript@7.0.0: {}
@@ -4297,7 +4554,7 @@ snapshots:
 
   semver@7.7.4: {}
 
-  semver@7.8.4: {}
+  semver@7.8.5: {}
 
   serialize-javascript@6.0.2:
     dependencies:
@@ -4362,8 +4619,8 @@ snapshots:
       eslint-scope: 8.4.0
       eslint-visitor-keys: 4.2.1
       espree: 10.1.0
-      postcss: 8.5.9
-      postcss-scss: 4.0.9(postcss@8.5.9)
+      postcss: 8.5.15
+      postcss-scss: 4.0.9(postcss@8.5.15)
       postcss-selector-parser: 7.1.0
     optionalDependencies:
       svelte: link:packages/svelte
@@ -4390,6 +4647,11 @@ snapshots:
       fdir: 6.5.0(picomatch@4.0.4)
       picomatch: 4.0.4
 
+  tinyglobby@0.2.17:
+    dependencies:
+      fdir: 6.5.0(picomatch@4.0.4)
+      picomatch: 4.0.4
+
   tinyrainbow@3.1.0: {}
 
   tldts-core@6.1.64: {}
@@ -4467,22 +4729,22 @@ snapshots:
 
   v8-natives@1.2.5: {}
 
-  vite-dev-rpc@1.1.0(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
+  vite-dev-rpc@1.1.0(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
     dependencies:
       birpc: 2.5.0
-      vite: 7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
-      vite-hot-client: 2.1.0(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+      vite: 7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+      vite-hot-client: 2.1.0(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
 
-  vite-hot-client@2.1.0(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
+  vite-hot-client@2.1.0(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
     dependencies:
-      vite: 7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+      vite: 7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
 
-  vite-plugin-devtools-json@1.0.0(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
+  vite-plugin-devtools-json@1.0.0(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
     dependencies:
       uuid: 11.1.0
-      vite: 7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+      vite: 7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
 
-  vite-plugin-inspect@11.3.3(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
+  vite-plugin-inspect@11.3.3(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
     dependencies:
       ansis: 4.1.0
       debug: 4.4.3
@@ -4492,19 +4754,19 @@ snapshots:
       perfect-debounce: 2.0.0
       sirv: 3.0.2
       unplugin-utils: 0.3.0
-      vite: 7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
-      vite-dev-rpc: 1.1.0(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+      vite: 7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+      vite-dev-rpc: 1.1.0(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
     transitivePeerDependencies:
       - supports-color
 
-  vite@7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0):
+  vite@7.3.5(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0):
     dependencies:
       esbuild: 0.27.7
       fdir: 6.5.0(picomatch@4.0.4)
       picomatch: 4.0.4
-      postcss: 8.5.9
-      rollup: 4.60.1
-      tinyglobby: 0.2.15
+      postcss: 8.5.15
+      rollup: 4.62.2
+      tinyglobby: 0.2.17
     optionalDependencies:
       '@types/node': 20.19.17
       fsevents: 2.3.3
@@ -4512,14 +4774,14 @@ snapshots:
       sass: 1.70.0
       terser: 5.27.0
 
-  vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0):
+  vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0):
     dependencies:
       esbuild: 0.27.7
       fdir: 6.5.0(picomatch@4.0.4)
       picomatch: 4.0.4
-      postcss: 8.5.9
-      rollup: 4.60.1
-      tinyglobby: 0.2.15
+      postcss: 8.5.15
+      rollup: 4.62.2
+      tinyglobby: 0.2.17
     optionalDependencies:
       '@types/node': 24.5.2
       fsevents: 2.3.3
@@ -4527,14 +4789,14 @@ snapshots:
       sass: 1.70.0
       terser: 5.27.0
 
-  vitefu@1.1.1(vite@7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
+  vitefu@1.1.1(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
     optionalDependencies:
-      vite: 7.3.2(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+      vite: 7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
 
-  vitest@4.1.7(@types/node@20.19.17)(@vitest/coverage-v8@4.1.7)(jsdom@25.0.1)(vite@7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
+  vitest@4.1.7(@types/node@20.19.17)(@vitest/coverage-v8@4.1.7)(jsdom@25.0.1)(vite@7.3.5(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
     dependencies:
       '@vitest/expect': 4.1.7
-      '@vitest/mocker': 4.1.7(vite@7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+      '@vitest/mocker': 4.1.7(vite@7.3.5(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
       '@vitest/pretty-format': 4.1.7
       '@vitest/runner': 4.1.7
       '@vitest/snapshot': 4.1.7
@@ -4551,7 +4813,7 @@ snapshots:
       tinyexec: 1.1.2
       tinyglobby: 0.2.15
       tinyrainbow: 3.1.0
-      vite: 7.3.2(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+      vite: 7.3.5(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
       why-is-node-running: 2.3.0
     optionalDependencies:
       '@types/node': 20.19.17

From a6560bbe08bd25105152e23cb80465a9e7d0c95a Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Fri, 21 Aug 2026 16:29:02 -0400
Subject: [PATCH 171/222] fix: don't resurrect outroing elements when an
 ancestor block is paused and resumed (#18431)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Fixes #15604

Given two nested blocks that both transition:

```svelte
{#if fetching}
	<p>loading</p>
{:else}
	<div transition:fade>
		{#if shown}
			<div class="red" transition:fade|global>red square</div>
		{/if}
	</div>
{/if}
```

and this sequence, where each step happens before the previous fade
finished:

```js
shown = false;    // red square starts fading out
fetching = true;  // outer block starts fading out too
fetching = false; // 50ms later
```

the red square should finish fading out and be removed, since `shown` is
still false. Instead it fades back in and stays on screen: resuming the
outer block walks the whole subtree, clears `INERT` on every effect and
plays `in()` on every transition it finds — including the inner block's,
so the square's outro is aborted and the removal callback waiting on it
never runs. The inner block has no reason to re-run on its own, `shown`
never changed again.

The root issue is that `INERT` records no ownership — it can't
distinguish "paused by the ancestor currently being resumed" (revive)
from "paused by its own block for its own reasons" (leave alone). The
pause side already has this restraint: `pause_children` refuses to touch
a subtree that is already `INERT`. The resume side had nothing to check.
This PR marks the one effect `pause_effect` was actually called on — the
root of the paused subtree — with a `PAUSED` flag, and gives resume the
same restraint:

```js
function resume_children(effect, local) {
	if ((effect.f & PAUSED) !== 0) return;
```

so a resume can only ever undo its own pause; the flag is only cleared
by `resume_effect` on that exact effect. If `shown` flips back to true
while the outer block is paused, this still works: the inner block
effect carries no `PAUSED` itself, so it is resumed and rescheduled,
re-evaluates its condition and revives its own branch.
---
 .changeset/quiet-falcons-search.md            |  5 ++++
 .../svelte/src/internal/client/constants.js   |  7 +++++
 .../src/internal/client/reactivity/effects.js |  9 +++++-
 .../_config.js                                | 23 +++++++++++++++
 .../main.svelte                               | 19 ++++++++++++
 .../_config.js                                | 24 +++++++++++++++
 .../main.svelte                               | 19 ++++++++++++
 .../_config.js                                | 29 +++++++++++++++++++
 .../main.svelte                               | 19 ++++++++++++
 9 files changed, 153 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/quiet-falcons-search.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume-each/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume-each/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume-flipback/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume-flipback/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume/main.svelte

diff --git a/.changeset/quiet-falcons-search.md b/.changeset/quiet-falcons-search.md
new file mode 100644
index 0000000000..8c5c4dedca
--- /dev/null
+++ b/.changeset/quiet-falcons-search.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: don't resurrect outroing elements when an ancestor block is paused and resumed
diff --git a/packages/svelte/src/internal/client/constants.js b/packages/svelte/src/internal/client/constants.js
index b92ea8598b..e0b7a8779b 100644
--- a/packages/svelte/src/internal/client/constants.js
+++ b/packages/svelte/src/internal/client/constants.js
@@ -15,6 +15,13 @@ export const BLOCK_EFFECT = 1 << 4;
 export const BRANCH_EFFECT = 1 << 5;
 export const ROOT_EFFECT = 1 << 6;
 export const BOUNDARY_EFFECT = 1 << 7;
+/**
+ * Set on the effect that `pause_effect` was called on, i.e. the root of a paused subtree,
+ * as opposed to its descendants which are merely `INERT`. This allows `resume_effect` on
+ * an ancestor to skip subtrees that were paused for their own reasons (such as a block
+ * whose condition is still false) rather than resurrecting them
+ */
+export const PAUSED = 1 << 8;
 /**
  * Indicates that a reaction is connected to an effect root — either it is an effect,
  * or it is a derived that is depended on by at least one effect. If a derived has
diff --git a/packages/svelte/src/internal/client/reactivity/effects.js b/packages/svelte/src/internal/client/reactivity/effects.js
index 7e53138aae..e69a639a94 100644
--- a/packages/svelte/src/internal/client/reactivity/effects.js
+++ b/packages/svelte/src/internal/client/reactivity/effects.js
@@ -34,7 +34,8 @@ import {
 	ASYNC,
 	CONNECTED,
 	MANAGED_EFFECT,
-	DESTROYING
+	DESTROYING,
+	PAUSED
 } from '#client/constants';
 import { invoke_error_boundary } from '../error-handling.js';
 import * as e from '../errors.js';
@@ -616,6 +617,7 @@ export function pause_effect(effect, callback, destroy = true) {
 	/** @type {TransitionManager[]} */
 	var transitions = [];
 
+	effect.f |= PAUSED;
 	pause_children(effect, transitions, true);
 
 	var fn = () => {
@@ -683,6 +685,7 @@ function pause_children(effect, transitions, local) {
  * @param {Effect} effect
  */
 export function resume_effect(effect) {
+	effect.f &= ~PAUSED;
 	resume_children(effect, true);
 }
 
@@ -691,6 +694,10 @@ export function resume_effect(effect) {
  * @param {boolean} local
  */
 function resume_children(effect, local) {
+	// this subtree was paused for its own reasons (e.g. a block whose condition
+	// is still false) — its controller will resume or destroy it
+	if ((effect.f & PAUSED) !== 0) return;
+
 	if ((effect.f & INERT) === 0) return;
 	effect.f ^= INERT;
 
diff --git a/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume-each/_config.js b/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume-each/_config.js
new file mode 100644
index 0000000000..7ccfd72f00
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume-each/_config.js
@@ -0,0 +1,23 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+// #15604 — a removed each item mid-outro must not be resurrected by an ancestor pause/resume
+export default test({
+	test({ assert, target, raf }) {
+		const [remove, fetch] = target.querySelectorAll('button');
+
+		raf.tick(200);
+		assert.equal(target.querySelectorAll('.item').length, 3);
+
+		flushSync(() => remove.click());
+
+		flushSync(() => fetch.click());
+		raf.tick(30);
+
+		flushSync(() => fetch.click());
+		raf.tick(2000);
+
+		const items = [...target.querySelectorAll('.item')].map((el) => el.textContent);
+		assert.deepEqual(items, ['a', 'c']);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume-each/main.svelte b/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume-each/main.svelte
new file mode 100644
index 0000000000..36e685e3c8
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume-each/main.svelte
@@ -0,0 +1,19 @@
+<script>
+	import { fade } from 'svelte/transition';
+
+	let fetching = $state(false);
+	let items = $state(['a', 'b', 'c']);
+</script>
+
+<button onclick={() => (items = items.filter((i) => i !== 'b'))}>remove</button>
+<button onclick={() => (fetching = !fetching)}>fetch</button>
+
+{#if fetching}
+	<p>loading</p>
+{:else}
+	<div transition:fade={{ duration: 100 }}>
+		{#each items as item (item)}
+			<div class="item" transition:fade|global={{ duration: 100 }}>{item}</div>
+		{/each}
+	</div>
+{/if}
diff --git a/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume-flipback/_config.js b/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume-flipback/_config.js
new file mode 100644
index 0000000000..a8e5e99bbf
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume-flipback/_config.js
@@ -0,0 +1,24 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+// #15604 companion — flipping the condition back while the ancestor is paused must still revive the element
+export default test({
+	test({ assert, target, raf }) {
+		const [toggle, fetch] = target.querySelectorAll('button');
+
+		raf.tick(200);
+		assert.ok(target.querySelector('.red'));
+
+		flushSync(() => toggle.click());
+
+		flushSync(() => fetch.click());
+		raf.tick(30);
+
+		flushSync(() => toggle.click());
+
+		flushSync(() => fetch.click());
+		raf.tick(2000);
+
+		assert.ok(target.querySelector('.red'));
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume-flipback/main.svelte b/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume-flipback/main.svelte
new file mode 100644
index 0000000000..71a3ea2090
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume-flipback/main.svelte
@@ -0,0 +1,19 @@
+<script>
+	import { fade } from 'svelte/transition';
+
+	let fetching = $state(false);
+	let shown = $state(true);
+</script>
+
+<button onclick={() => (shown = !shown)}>toggle</button>
+<button onclick={() => (fetching = !fetching)}>fetch</button>
+
+{#if fetching}
+	<p>loading</p>
+{:else}
+	<div transition:fade={{ duration: 100 }}>
+		{#if shown}
+			<div class="red" transition:fade|global={{ duration: 100 }}>red</div>
+		{/if}
+	</div>
+{/if}
diff --git a/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume/_config.js b/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume/_config.js
new file mode 100644
index 0000000000..4009eea204
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume/_config.js
@@ -0,0 +1,29 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+// #15604 — an element mid-outro must not be resurrected when an ancestor
+// block is paused and resumed while the element's own condition is still false.
+// The outer `transition:fade` matters: it keeps the outer branch alive (pending
+// its own outro) so that toggling back takes the resume path
+export default test({
+	test({ assert, target, raf }) {
+		const [hide, fetch] = target.querySelectorAll('button');
+
+		// let the mount intro (dom variant) finish
+		raf.tick(200);
+		assert.ok(target.querySelector('.red'));
+
+		// start the outro of the inner block
+		flushSync(() => hide.click());
+
+		// pause the outer block while the outro is in flight...
+		flushSync(() => fetch.click());
+		raf.tick(250);
+
+		// ...then resume it before either outro completes
+		flushSync(() => fetch.click());
+		raf.tick(2000);
+
+		assert.equal(target.querySelector('.red'), null);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume/main.svelte b/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume/main.svelte
new file mode 100644
index 0000000000..0060401b8e
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/transition-global-nested-resume/main.svelte
@@ -0,0 +1,19 @@
+<script>
+	import { fade } from 'svelte/transition';
+
+	let fetching = $state(false);
+	let shown = $state(true);
+</script>
+
+<button onclick={() => (shown = false)}>hide</button>
+<button onclick={() => (fetching = !fetching)}>fetch</button>
+
+{#if fetching}
+	<p>loading</p>
+{:else}
+	<div transition:fade={{ duration: 100 }}>
+		{#if shown}
+			<div class="red" transition:fade|global={{ duration: 100 }}>red</div>
+		{/if}
+	</div>
+{/if}

From 2ac73663918645a20e4fe2294ff1073ca306d973 Mon Sep 17 00:00:00 2001
From: PD Shaheed Ali Khan <phenomenalonep28@gmail.com>
Date: Sat, 22 Aug 2026 02:18:58 +0530
Subject: [PATCH 172/222] perf: optimize simple object destructuring in @const
 tags (#18390)

This PR resolves a `TODO` in `ConstTag.js` regarding the optimization of
simple object pattern matching cases like `{@const { x } = y}`.

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/optimize-const-tag.md              |  5 ++++
 .../src/compiler/phases/1-parse/acorn.js      |  2 +-
 .../3-transform/client/visitors/ConstTag.js   | 23 ++++++++++++++-----
 3 files changed, 23 insertions(+), 7 deletions(-)
 create mode 100644 .changeset/optimize-const-tag.md

diff --git a/.changeset/optimize-const-tag.md b/.changeset/optimize-const-tag.md
new file mode 100644
index 0000000000..90c6a6b5d2
--- /dev/null
+++ b/.changeset/optimize-const-tag.md
@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+perf: optimize simple object destructuring in `@const` tags
diff --git a/packages/svelte/src/compiler/phases/1-parse/acorn.js b/packages/svelte/src/compiler/phases/1-parse/acorn.js
index fb60c228c5..070183f984 100644
--- a/packages/svelte/src/compiler/phases/1-parse/acorn.js
+++ b/packages/svelte/src/compiler/phases/1-parse/acorn.js
@@ -59,7 +59,7 @@ export function parse(source, comments, typescript, is_script) {
 
 		return /** @type {Program} */ (ast);
 	} catch (err) {
-		// TODO the `return` in necessary for TS<7 due to a bug; otherwise
+		// TODO the `return` is necessary for TS<7 due to a bug; otherwise
 		// the `finally` block is regarded as unreachable
 		return handle_parse_error(err);
 	} finally {
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/ConstTag.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/ConstTag.js
index d05d7a8ed9..63c84a507c 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/ConstTag.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/ConstTag.js
@@ -45,18 +45,29 @@ export function ConstTag(node, context) {
 			transform
 		});
 
-		// TODO optimise the simple `{ x } = y` case — we can just return `y`
-		// instead of destructuring it only to return a new object
+		const is_simple_object_pattern =
+			declaration.id.type === 'ObjectPattern' &&
+			declaration.id.properties.every(
+				(p) =>
+					p.type === 'Property' &&
+					!p.computed &&
+					p.key.type === 'Identifier' &&
+					p.value.type === 'Identifier' &&
+					p.key.name === p.value.name
+			);
+
 		const init = build_expression(
 			{ ...context, state: child_state },
 			declaration.init,
 			node.metadata.expression
 		);
 
-		const block = b.block([
-			b.const(/** @type {Pattern} */ (context.visit(declaration.id, child_state)), init),
-			b.return(b.object(identifiers.map((node) => b.prop('init', node, node))))
-		]);
+		const block = is_simple_object_pattern
+			? b.block([b.return(init)])
+			: b.block([
+					b.const(/** @type {Pattern} */ (context.visit(declaration.id, child_state)), init),
+					b.return(b.object(identifiers.map((node) => b.prop('init', node, node))))
+				]);
 
 		let expression = create_derived(context.state, block, node.metadata.expression.has_await);
 

From 63b4c3652dfe0d4b692dd9278b5f668a0b67a76b Mon Sep 17 00:00:00 2001
From: sliang-code <sihanlia@andrew.cmu.edu>
Date: Sat, 22 Aug 2026 04:59:35 +0800
Subject: [PATCH 173/222] fix: don't apply scoped CSS class to elements inside
 <svelte:head> (#18160)

skip elements inside head, they should not get hashes

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/hungry-plums-roll.md                       |  5 +++++
 .../src/compiler/phases/2-analyze/css/css-prune.js    | 10 ++++++++++
 .../samples/head-css-no-class/_expected_head.html     |  1 +
 .../hydration/samples/head-css-no-class/main.svelte   | 11 +++++++++++
 4 files changed, 27 insertions(+)
 create mode 100644 .changeset/hungry-plums-roll.md
 create mode 100644 packages/svelte/tests/hydration/samples/head-css-no-class/_expected_head.html
 create mode 100644 packages/svelte/tests/hydration/samples/head-css-no-class/main.svelte

diff --git a/.changeset/hungry-plums-roll.md b/.changeset/hungry-plums-roll.md
new file mode 100644
index 0000000000..b5e3688eb5
--- /dev/null
+++ b/.changeset/hungry-plums-roll.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: never apply class hash to elements inside `<svelte:head>`
diff --git a/packages/svelte/src/compiler/phases/2-analyze/css/css-prune.js b/packages/svelte/src/compiler/phases/2-analyze/css/css-prune.js
index 39f485a9f7..dff6bb9b5a 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/css/css-prune.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/css/css-prune.js
@@ -122,6 +122,13 @@ const any_selector = {
  */
 const seen = new Set();
 
+/**
+ * @param {Compiler.AST.RegularElement | Compiler.AST.SvelteElement | Compiler.AST.RenderTag | Compiler.AST.Component | Compiler.AST.SvelteComponent | Compiler.AST.SvelteSelf} node
+ */
+function is_inside_svelte_head(node) {
+	return node.metadata.path.some((ancestor) => ancestor.type === 'SvelteHead');
+}
+
 /**
  *
  * @param {Compiler.AST.CSS.StyleSheet} stylesheet
@@ -143,6 +150,9 @@ export function prune(stylesheet, elements) {
 				seen.clear();
 
 				if (
+					// Elements rendered through <svelte:head> are not style-scopable.
+					// Prevent css hash injection (class="s-...") on tags like <meta>, <link>, <script>.
+					!is_inside_svelte_head(element) &&
 					apply_selector(
 						selectors,
 						/** @type {Compiler.AST.CSS.Rule} */ (node.metadata.rule),
diff --git a/packages/svelte/tests/hydration/samples/head-css-no-class/_expected_head.html b/packages/svelte/tests/hydration/samples/head-css-no-class/_expected_head.html
new file mode 100644
index 0000000000..497ca987cc
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/head-css-no-class/_expected_head.html
@@ -0,0 +1 @@
+<meta name="author" content="Re:Designed"> <link rel="author" href="https://example.com"> <script type="application/ld+json"></script>
\ No newline at end of file
diff --git a/packages/svelte/tests/hydration/samples/head-css-no-class/main.svelte b/packages/svelte/tests/hydration/samples/head-css-no-class/main.svelte
new file mode 100644
index 0000000000..29336a17ba
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/head-css-no-class/main.svelte
@@ -0,0 +1,11 @@
+<svelte:head>
+	<meta name="author" content="Re:Designed" />
+	<link rel="author" href="https://example.com" />
+	<script type="application/ld+json"></script>
+</svelte:head>
+
+<div>dummy</div>
+
+<style>
+	* { color: red }
+</style>

From 15720b16a5ef33e3e1f4301c77b94ec375070e73 Mon Sep 17 00:00:00 2001
From: ChaseCopeland <106773491+chasec22@users.noreply.github.com>
Date: Fri, 21 Aug 2026 14:32:03 -0700
Subject: [PATCH 174/222] docs: Updated docs to include information on easing
 functions (#16070)

closes #15992

This is a minor update to the easing documents. It adds an overview
description for the module and short descriptions for each of the easing
functions.

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Co-authored-by: vercel[bot] <35613825+vercel[bot]@users.noreply.github.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .../docs/98-reference/21-svelte-easing.md     |   2 +
 packages/svelte/src/easing/index.js           |  62 +++++++
 packages/svelte/types/index.d.ts              | 154 ++++++++++++++----
 3 files changed, 188 insertions(+), 30 deletions(-)

diff --git a/documentation/docs/98-reference/21-svelte-easing.md b/documentation/docs/98-reference/21-svelte-easing.md
index 3f47963cde..a2b49ff4a9 100644
--- a/documentation/docs/98-reference/21-svelte-easing.md
+++ b/documentation/docs/98-reference/21-svelte-easing.md
@@ -2,4 +2,6 @@
 title: svelte/easing
 ---
 
+This module provides a set of functions that allow you to manipulate time values in different ways. It’s particularly useful for animations when combined with the `motion` module. 
+
 > MODULE: svelte/easing
diff --git a/packages/svelte/src/easing/index.js b/packages/svelte/src/easing/index.js
index 08c86933ab..c2f7e63bc0 100644
--- a/packages/svelte/src/easing/index.js
+++ b/packages/svelte/src/easing/index.js
@@ -4,6 +4,8 @@ Distributed under MIT License https://github.com/mattdesl/eases/blob/master/LICE
 */
 
 /**
+ * Returns value as is.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -12,6 +14,8 @@ export function linear(t) {
 }
 
 /**
+ * Rebound effect on start and end of value range.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -22,6 +26,8 @@ export function backInOut(t) {
 }
 
 /**
+ * Rebound effect on start.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -31,6 +37,8 @@ export function backIn(t) {
 }
 
 /**
+ * Rebound effect on end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -40,6 +48,8 @@ export function backOut(t) {
 }
 
 /**
+ * Bounce effect on end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -61,6 +71,8 @@ export function bounceOut(t) {
 }
 
 /**
+ * Bounce effect on start and end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -69,6 +81,8 @@ export function bounceInOut(t) {
 }
 
 /**
+ * Bounce effect on start.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -77,6 +91,8 @@ export function bounceIn(t) {
 }
 
 /**
+ * Circular effect, accelerate on start, decelerate towards end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -86,6 +102,8 @@ export function circInOut(t) {
 }
 
 /**
+ * Circular effect, accelerate on start.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -94,6 +112,8 @@ export function circIn(t) {
 }
 
 /**
+ * Circular effect, decelerate towards end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -102,6 +122,8 @@ export function circOut(t) {
 }
 
 /**
+ * Cubic scaling, accelerate on start, decelerate towards end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -110,6 +132,8 @@ export function cubicInOut(t) {
 }
 
 /**
+ * Cubic scaling, accelerate on start
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -118,6 +142,8 @@ export function cubicIn(t) {
 }
 
 /**
+ * Cubic scaling, decelerate towards end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -127,6 +153,8 @@ export function cubicOut(t) {
 }
 
 /**
+ * Elastic effect on start and end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -140,6 +168,8 @@ export function elasticInOut(t) {
 }
 
 /**
+ * Elastic effect on start.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -148,6 +178,8 @@ export function elasticIn(t) {
 }
 
 /**
+ * Elastic effect on end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -156,6 +188,8 @@ export function elasticOut(t) {
 }
 
 /**
+ * Exponential effect on start and end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -168,6 +202,8 @@ export function expoInOut(t) {
 }
 
 /**
+ * Exponential effect on start.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -176,6 +212,8 @@ export function expoIn(t) {
 }
 
 /**
+ * Exponential effect on end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -184,6 +222,8 @@ export function expoOut(t) {
 }
 
 /**
+ * Quadratic scaling, accelerate on start, decelerate towards end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -195,6 +235,8 @@ export function quadInOut(t) {
 }
 
 /**
+ * Quadratic scaling, accelerate on start.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -203,6 +245,8 @@ export function quadIn(t) {
 }
 
 /**
+ * Quadratic scaling, decelerate towards end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -211,6 +255,8 @@ export function quadOut(t) {
 }
 
 /**
+ * Quartic scaling, accelerate on start, decelerate towards end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -219,6 +265,8 @@ export function quartInOut(t) {
 }
 
 /**
+ * Quartic scaling, accelerate on start.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -227,6 +275,8 @@ export function quartIn(t) {
 }
 
 /**
+ * Quartic scaling, decelerate towards end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -235,6 +285,8 @@ export function quartOut(t) {
 }
 
 /**
+ * Quintic scaling, accelerate on start, decelerate towards end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -244,6 +296,8 @@ export function quintInOut(t) {
 }
 
 /**
+ * Quintic scaling, accelerate on start.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -252,6 +306,8 @@ export function quintIn(t) {
 }
 
 /**
+ * Quintic scaling, decelerate towards end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -260,6 +316,8 @@ export function quintOut(t) {
 }
 
 /**
+ * Sinusoidal effect, accelerate on start, decelerate towards end.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -268,6 +326,8 @@ export function sineInOut(t) {
 }
 
 /**
+ * Sinusoidal effect, accelerate on start.
+ *
  * @param {number} t
  * @returns {number}
  */
@@ -278,6 +338,8 @@ export function sineIn(t) {
 }
 
 /**
+ * Sinusoidal effect, decelerate towards end.
+ *
  * @param {number} t
  * @returns {number}
  */
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index 96be34ef9e..dcc6dc5914 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -1875,66 +1875,160 @@ declare module 'svelte/compiler' {
 }
 
 declare module 'svelte/easing' {
+	/**
+	 * Returns value as is.
+	 *
+	 * */
 	export function linear(t: number): number;
-
+	/**
+	 * Rebound effect on start and end of value range.
+	 *
+	 * */
 	export function backInOut(t: number): number;
-
+	/**
+	 * Rebound effect on start.
+	 *
+	 * */
 	export function backIn(t: number): number;
-
+	/**
+	 * Rebound effect on end.
+	 *
+	 * */
 	export function backOut(t: number): number;
-
+	/**
+	 * Bounce effect on end.
+	 *
+	 * */
 	export function bounceOut(t: number): number;
-
+	/**
+	 * Bounce effect on start and end.
+	 *
+	 * */
 	export function bounceInOut(t: number): number;
-
+	/**
+	 * Bounce effect on start.
+	 *
+	 * */
 	export function bounceIn(t: number): number;
-
+	/**
+	 * Circular effect, accelerate on start, decelerate towards end.
+	 *
+	 * */
 	export function circInOut(t: number): number;
-
+	/**
+	 * Circular effect, accelerate on start.
+	 *
+	 * */
 	export function circIn(t: number): number;
-
+	/**
+	 * Circular effect, decelerate towards end.
+	 *
+	 * */
 	export function circOut(t: number): number;
-
+	/**
+	 * Cubic scaling, accelerate on start, decelerate towards end.
+	 *
+	 * */
 	export function cubicInOut(t: number): number;
-
+	/**
+	 * Cubic scaling, accelerate on start
+	 *
+	 * */
 	export function cubicIn(t: number): number;
-
+	/**
+	 * Cubic scaling, decelerate towards end.
+	 *
+	 * */
 	export function cubicOut(t: number): number;
-
+	/**
+	 * Elastic effect on start and end.
+	 *
+	 * */
 	export function elasticInOut(t: number): number;
-
+	/**
+	 * Elastic effect on start.
+	 *
+	 * */
 	export function elasticIn(t: number): number;
-
+	/**
+	 * Elastic effect on end.
+	 *
+	 * */
 	export function elasticOut(t: number): number;
-
+	/**
+	 * Exponential effect on start and end.
+	 *
+	 * */
 	export function expoInOut(t: number): number;
-
+	/**
+	 * Exponential effect on start.
+	 *
+	 * */
 	export function expoIn(t: number): number;
-
+	/**
+	 * Exponential effect on end.
+	 *
+	 * */
 	export function expoOut(t: number): number;
-
+	/**
+	 * Quadratic scaling, accelerate on start, decelerate towards end.
+	 *
+	 * */
 	export function quadInOut(t: number): number;
-
+	/**
+	 * Quadratic scaling, accelerate on start.
+	 *
+	 * */
 	export function quadIn(t: number): number;
-
+	/**
+	 * Quadratic scaling, decelerate towards end.
+	 *
+	 * */
 	export function quadOut(t: number): number;
-
+	/**
+	 * Quartic scaling, accelerate on start, decelerate towards end.
+	 *
+	 * */
 	export function quartInOut(t: number): number;
-
+	/**
+	 * Quartic scaling, accelerate on start.
+	 *
+	 * */
 	export function quartIn(t: number): number;
-
+	/**
+	 * Quartic scaling, decelerate towards end.
+	 *
+	 * */
 	export function quartOut(t: number): number;
-
+	/**
+	 * Quintic scaling, accelerate on start, decelerate towards end.
+	 *
+	 * */
 	export function quintInOut(t: number): number;
-
+	/**
+	 * Quintic scaling, accelerate on start.
+	 *
+	 * */
 	export function quintIn(t: number): number;
-
+	/**
+	 * Quintic scaling, decelerate towards end.
+	 *
+	 * */
 	export function quintOut(t: number): number;
-
+	/**
+	 * Sinusoidal effect, accelerate on start, decelerate towards end.
+	 *
+	 * */
 	export function sineInOut(t: number): number;
-
+	/**
+	 * Sinusoidal effect, accelerate on start.
+	 *
+	 * */
 	export function sineIn(t: number): number;
-
+	/**
+	 * Sinusoidal effect, decelerate towards end.
+	 *
+	 * */
 	export function sineOut(t: number): number;
 
 	export {};

From 4b61851ec80054c465b23603aafe2a7d69819438 Mon Sep 17 00:00:00 2001
From: "svelte-triage-bot[bot]"
 <316883489+svelte-triage-bot[bot]@users.noreply.github.com>
Date: Mon, 24 Aug 2026 13:59:50 +0200
Subject: [PATCH 175/222] fix: clean up svelte:head anchors on unmount (#18697)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

include client-created <svelte:head> anchors in the head effect’s DOM range
remove anchors through the existing HEAD_EFFECT teardown
add client and hydration regression coverage for repeated mount/unmount cycles
Fixes #18695

---------

Co-authored-by: svelte-triage-bot <team@svelte.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/clean-head-anchors.md              |  5 +++++
 .../internal/client/dom/blocks/svelte-head.js |  8 ++++++++
 .../svelte-head-anchor-cleanup/Head.svelte    |  3 +++
 .../svelte-head-anchor-cleanup/_config.js     | 19 +++++++++++++++++++
 .../svelte-head-anchor-cleanup/main.svelte    | 11 +++++++++++
 5 files changed, 46 insertions(+)
 create mode 100644 .changeset/clean-head-anchors.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/svelte-head-anchor-cleanup/Head.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/svelte-head-anchor-cleanup/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/svelte-head-anchor-cleanup/main.svelte

diff --git a/.changeset/clean-head-anchors.md b/.changeset/clean-head-anchors.md
new file mode 100644
index 0000000000..d58283f502
--- /dev/null
+++ b/.changeset/clean-head-anchors.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: remove `<svelte:head>` anchors on unmount
diff --git a/packages/svelte/src/internal/client/dom/blocks/svelte-head.js b/packages/svelte/src/internal/client/dom/blocks/svelte-head.js
index 5721f7b056..d22d74b275 100644
--- a/packages/svelte/src/internal/client/dom/blocks/svelte-head.js
+++ b/packages/svelte/src/internal/client/dom/blocks/svelte-head.js
@@ -52,6 +52,14 @@ export function head(hash, render_fn) {
 		block(() => {
 			var e = branch(() => render_fn(anchor));
 			e.f |= HEAD_EFFECT;
+
+			if (!hydrating) {
+				if (e.nodes === null) {
+					e.nodes = { start: anchor, end: anchor, a: null, t: null };
+				} else {
+					e.nodes.end = anchor;
+				}
+			}
 		});
 	} finally {
 		if (was_hydrating) {
diff --git a/packages/svelte/tests/runtime-runes/samples/svelte-head-anchor-cleanup/Head.svelte b/packages/svelte/tests/runtime-runes/samples/svelte-head-anchor-cleanup/Head.svelte
new file mode 100644
index 0000000000..fa5ae4a349
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/svelte-head-anchor-cleanup/Head.svelte
@@ -0,0 +1,3 @@
+<svelte:head>
+	<meta name="test" content="value" />
+</svelte:head>
diff --git a/packages/svelte/tests/runtime-runes/samples/svelte-head-anchor-cleanup/_config.js b/packages/svelte/tests/runtime-runes/samples/svelte-head-anchor-cleanup/_config.js
new file mode 100644
index 0000000000..57ef735497
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/svelte-head-anchor-cleanup/_config.js
@@ -0,0 +1,19 @@
+import { flushSync } from 'svelte';
+import { ok, test } from '../../test';
+
+export default test({
+	mode: ['client', 'hydrate'],
+
+	test({ assert, target, window }) {
+		const initial = window.document.head.childNodes.length;
+		const button = target.querySelector('button');
+		ok(button);
+
+		for (let i = 0; i < 3; i++) {
+			flushSync(() => button.click());
+			flushSync(() => button.click());
+		}
+
+		assert.equal(window.document.head.childNodes.length, initial);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/svelte-head-anchor-cleanup/main.svelte b/packages/svelte/tests/runtime-runes/samples/svelte-head-anchor-cleanup/main.svelte
new file mode 100644
index 0000000000..f4cfefbadf
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/svelte-head-anchor-cleanup/main.svelte
@@ -0,0 +1,11 @@
+<script>
+	import Head from './Head.svelte';
+
+	let show = $state(false);
+</script>
+
+<button onclick={() => (show = !show)}>toggle</button>
+
+{#if show}
+	<Head />
+{/if}

From 721244ad3ba75675414521d02af8581dcb5902c6 Mon Sep 17 00:00:00 2001
From: "svelte-triage-bot[bot]"
 <316883489+svelte-triage-bot[bot]@users.noreply.github.com>
Date: Mon, 24 Aug 2026 14:14:18 +0200
Subject: [PATCH 176/222] fix: track SvelteDate snapshots in reactions (#18700)

Read the Date value through `getTime()` before cloning it to get reactive updates from `SvelteDate`.

Closes #18698

---------

Co-authored-by: svelte-triage-bot <team@svelte.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/calm-dates-track.md                      |  5 +++++
 packages/svelte/src/internal/shared/clone.js        |  2 ++
 .../samples/state-snapshot-svelte-date/_config.js   | 13 +++++++++++++
 .../samples/state-snapshot-svelte-date/main.svelte  |  9 +++++++++
 4 files changed, 29 insertions(+)
 create mode 100644 .changeset/calm-dates-track.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/state-snapshot-svelte-date/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/state-snapshot-svelte-date/main.svelte

diff --git a/.changeset/calm-dates-track.md b/.changeset/calm-dates-track.md
new file mode 100644
index 0000000000..e7275ae556
--- /dev/null
+++ b/.changeset/calm-dates-track.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: track SvelteDate snapshots in reactions
diff --git a/packages/svelte/src/internal/shared/clone.js b/packages/svelte/src/internal/shared/clone.js
index 1a83adf8c5..ba0c731047 100644
--- a/packages/svelte/src/internal/shared/clone.js
+++ b/packages/svelte/src/internal/shared/clone.js
@@ -105,6 +105,8 @@ function clone(value, cloned, path, paths, original = null, no_tojson = false) {
 		}
 
 		if (value instanceof Date) {
+			// Ensure SvelteDate snapshots are tracked
+			value.getTime();
 			return /** @type {Snapshot<T>} */ (structuredClone(value));
 		}
 
diff --git a/packages/svelte/tests/runtime-runes/samples/state-snapshot-svelte-date/_config.js b/packages/svelte/tests/runtime-runes/samples/state-snapshot-svelte-date/_config.js
new file mode 100644
index 0000000000..53d8e1d4ff
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/state-snapshot-svelte-date/_config.js
@@ -0,0 +1,13 @@
+import { test } from '../../test';
+import { tick } from 'svelte';
+
+export default test({
+	async test({ assert, target }) {
+		assert.htmlEqual(target.innerHTML, '<button>update</button><p>1970-01-01T00:00:00.000Z</p>');
+
+		target.querySelector('button')?.click();
+		await tick();
+
+		assert.htmlEqual(target.innerHTML, '<button>update</button><p>1970-01-02T00:00:00.000Z</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/state-snapshot-svelte-date/main.svelte b/packages/svelte/tests/runtime-runes/samples/state-snapshot-svelte-date/main.svelte
new file mode 100644
index 0000000000..634a7ee3e8
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/state-snapshot-svelte-date/main.svelte
@@ -0,0 +1,9 @@
+<script>
+	import { SvelteDate } from 'svelte/reactivity';
+
+	const date = new SvelteDate(0);
+	const snapshot = $derived($state.snapshot(date));
+</script>
+
+<button onclick={() => date.setTime(86400000)}>update</button>
+<p>{snapshot.toISOString()}</p>

From 1be496f0a61bf7c1da912caab62804e5e173ca5b Mon Sep 17 00:00:00 2001
From: Bao Nguyen <39545125+giaBaoJS@users.noreply.github.com>
Date: Mon, 24 Aug 2026 20:14:16 +0700
Subject: [PATCH 177/222] fix: accept `onfocusin`/`onfocusout` in
 `a11y_mouse_events_have_key_events` (#18689)

Fixes #8089

focusin/focusout are the bubble variants of focus/blur

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/large-schools-smell.md                |  5 +++++
 .../98-reference/.generated/compile-warnings.md  |  2 +-
 .../svelte/messages/compile-warnings/a11y.md     |  2 +-
 .../2-analyze/visitors/shared/a11y/index.js      | 16 ++++++++++++++--
 .../input.svelte                                 |  4 ++++
 5 files changed, 25 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/large-schools-smell.md

diff --git a/.changeset/large-schools-smell.md b/.changeset/large-schools-smell.md
new file mode 100644
index 0000000000..61ef571f02
--- /dev/null
+++ b/.changeset/large-schools-smell.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: accept `onfocusin`/`onfocusout` in `a11y_mouse_events_have_key_events`
diff --git a/documentation/docs/98-reference/.generated/compile-warnings.md b/documentation/docs/98-reference/.generated/compile-warnings.md
index f372a010a5..237ec105f6 100644
--- a/documentation/docs/98-reference/.generated/compile-warnings.md
+++ b/documentation/docs/98-reference/.generated/compile-warnings.md
@@ -360,7 +360,7 @@ Enforce that heading elements (`h1`, `h2`, etc.) and anchors have content and th
 '%event%' event must be accompanied by '%accompanied_by%' event
 ```
 
-Enforce that `onmouseover` and `onmouseout` are accompanied by `onfocus` and `onblur`, respectively. This helps to ensure that any functionality triggered by these mouse events is also accessible to keyboard users.
+Enforce that `onmouseover` and `onmouseout` are accompanied by `onfocus` (or `onfocusin`) and `onblur` (or `onfocusout`), respectively. This helps to ensure that any functionality triggered by these mouse events is also accessible to keyboard users.
 
 ```svelte
 <!-- A11y: onmouseover must be accompanied by onfocus -->
diff --git a/packages/svelte/messages/compile-warnings/a11y.md b/packages/svelte/messages/compile-warnings/a11y.md
index 1f48ef0dd5..915032bb93 100644
--- a/packages/svelte/messages/compile-warnings/a11y.md
+++ b/packages/svelte/messages/compile-warnings/a11y.md
@@ -300,7 +300,7 @@ Enforce that heading elements (`h1`, `h2`, etc.) and anchors have content and th
 
 > '%event%' event must be accompanied by '%accompanied_by%' event
 
-Enforce that `onmouseover` and `onmouseout` are accompanied by `onfocus` and `onblur`, respectively. This helps to ensure that any functionality triggered by these mouse events is also accessible to keyboard users.
+Enforce that `onmouseover` and `onmouseout` are accompanied by `onfocus` (or `onfocusin`) and `onblur` (or `onfocusout`), respectively. This helps to ensure that any functionality triggered by these mouse events is also accessible to keyboard users.
 
 ```svelte
 <!-- A11y: onmouseover must be accompanied by onfocus -->
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/a11y/index.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/a11y/index.js
index a6e801cf5a..e09ab018a8 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/a11y/index.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/a11y/index.js
@@ -373,11 +373,23 @@ export function check_element(node, context) {
 		}
 	}
 
-	if (!has_spread && handlers.has('mouseover') && !handlers.has('focus')) {
+	// `focus`/`blur` don't bubble, so an element that isn't focusable itself can only be notified
+	// about focus changes inside it through `focusin`/`focusout` — accept those as well
+	if (
+		!has_spread &&
+		handlers.has('mouseover') &&
+		!handlers.has('focus') &&
+		!handlers.has('focusin')
+	) {
 		w.a11y_mouse_events_have_key_events(node, 'mouseover', 'focus');
 	}
 
-	if (!has_spread && handlers.has('mouseout') && !handlers.has('blur')) {
+	if (
+		!has_spread &&
+		handlers.has('mouseout') &&
+		!handlers.has('blur') &&
+		!handlers.has('focusout')
+	) {
 		w.a11y_mouse_events_have_key_events(node, 'mouseout', 'blur');
 	}
 
diff --git a/packages/svelte/tests/validator/samples/a11y-mouse-events-have-key-events/input.svelte b/packages/svelte/tests/validator/samples/a11y-mouse-events-have-key-events/input.svelte
index f9fe4f15c1..85e9384c98 100644
--- a/packages/svelte/tests/validator/samples/a11y-mouse-events-have-key-events/input.svelte
+++ b/packages/svelte/tests/validator/samples/a11y-mouse-events-have-key-events/input.svelte
@@ -17,3 +17,7 @@
 <div onmouseout={() => {}} onblur={() => {}}></div>
 <!-- svelte-ignore a11y_no_static_element_interactions -->
 <div onmouseout={() => {}} {...otherProps}></div>
+<!-- svelte-ignore a11y_no_static_element_interactions -->
+<div onmouseover={() => {}} onfocusin={() => {}}></div>
+<!-- svelte-ignore a11y_no_static_element_interactions -->
+<div onmouseout={() => {}} onfocusout={() => {}}></div>

From f2648b353778493494c6dd3a7d020b1f08eb5def Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Mon, 24 Aug 2026 13:01:48 -0400
Subject: [PATCH 178/222] fix: end a restored reaction context at the end of
 its synchronous segment (#18694)

When an async expression resumes after a pickled `await`, the thunk
returned by `save()` in `reactivity/async.js` calls `restore()` to
re-arm `active_reaction` for the rest of the expression, then disarms it
with `queue_micro_task(unset_context)`. Any microtask already queued
before that one runs inside the restored context. If it writes to a
source, `set()` throws `state_unsafe_mutation` in production, since the
guard is not dev-only. #18453 introduced the queued disarm and noted
this case in review as unavoidable. SvelteKit hits it in practice: its
fetch continuations write to internal `$state` (sveltejs/kit#16914), and
a user's `$derived((await q()).length)` resuming in the same tick makes
that write throw and drops the update signal.

The context restored by a `save` thunk now ends with the synchronous
segment it was restored in. A `restored` flag is set by the thunk and
consumed on entry to `save` and `track_reactivity_loss`, so every
suspension ends it; once an expression contains a pickled await, the
analysis pickles every later await in it too (`has_pickled_await` on
`ExpressionMetadata`), so a trailing await compiles to `$.save` rather
than a bare `await`. At the end of the body, `async_thunk` in
`3-transform/client/utils.js` wraps the return expression in
`$.unsave(...)` when the metadata has a pickled await. If the body
throws instead, the context is unset by `async_derived`'s existing
`finally`, as before. The queued microtask in `save` is removed.

Output is unchanged for expressions that pickle nothing (`$derived(await
a)` compiles byte for byte the same). Expressions with a pickled await
gain one `$.unsave(` call per body, and their trailing await becomes a
`$.save`, 4 to 6 bytes gzipped in the added tests. At runtime a boolean
write replaces a queued microtask per resume. `bench:compare` shows no
difference outside run-to-run noise.

Two runtime tests reproduce the throw without any library involved, one
in dev and one with the prod `await` shape, and fail on `main`.

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/quiet-context-segment.md           |   5 +
 .../src/compiler/phases/2-analyze/index.js    |   4 +-
 .../2-analyze/visitors/AwaitExpression.js     |  14 ++-
 .../2-analyze/visitors/CallExpression.js      |   2 +-
 .../phases/3-transform/client/utils.js        |  43 +++++--
 .../3-transform/client/visitors/AwaitBlock.js |  12 +-
 .../3-transform/client/visitors/ConstTag.js   |   4 +-
 .../client/visitors/DeclarationTag.js         |   3 +-
 .../3-transform/client/visitors/EachBlock.js  |   5 +-
 .../3-transform/client/visitors/HtmlTag.js    |   3 +-
 .../3-transform/client/visitors/IfBlock.js    |   3 +-
 .../3-transform/client/visitors/KeyBlock.js   |   3 +-
 .../client/visitors/SvelteElement.js          |   3 +-
 .../client/visitors/VariableDeclaration.js    |  15 ++-
 .../client/visitors/shared/utils.js           |  10 +-
 packages/svelte/src/compiler/phases/nodes.js  |   4 +
 .../svelte/src/compiler/phases/types.d.ts     |   2 +-
 packages/svelte/src/internal/client/index.js  |   1 +
 .../src/internal/client/reactivity/async.js   |  26 ++++-
 .../async-save-await-block-pending/_config.js |  20 ++++
 .../main.svelte                               |  14 +++
 .../_config.js                                |  22 ++++
 .../main.svelte                               |  20 ++++
 .../_config.js                                |  21 ++++
 .../main.svelte                               |  21 ++++
 .../async-save-throwing-expression/_config.js |  20 ++++
 .../main.svelte                               |  26 +++++
 .../_expected/client/index.svelte.js          |  14 ++-
 .../_expected/client/index.svelte.js          | 110 +++++++++++-------
 .../_expected/client/index.svelte.js          |  30 ++++-
 30 files changed, 393 insertions(+), 87 deletions(-)
 create mode 100644 .changeset/quiet-context-segment.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-save-await-block-pending/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-save-await-block-pending/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-save-foreign-microtask-mutation-prod/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-save-foreign-microtask-mutation-prod/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-save-foreign-microtask-mutation/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-save-foreign-microtask-mutation/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-save-throwing-expression/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-save-throwing-expression/main.svelte

diff --git a/.changeset/quiet-context-segment.md b/.changeset/quiet-context-segment.md
new file mode 100644
index 0000000000..7af36f8ed3
--- /dev/null
+++ b/.changeset/quiet-context-segment.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: end a restored reaction context at the end of its synchronous segment
diff --git a/packages/svelte/src/compiler/phases/2-analyze/index.js b/packages/svelte/src/compiler/phases/2-analyze/index.js
index 45f703901d..f6fb14a870 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/index.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/index.js
@@ -285,7 +285,7 @@ export function analyze_module(source, options) {
 		runes: true,
 		immutable: true,
 		tracing: false,
-		async_deriveds: new Set(),
+		async_deriveds: new Map(),
 		comments,
 		classes: new Map(),
 		pickled_awaits: new Set()
@@ -557,7 +557,7 @@ export function analyze_component(root, source, options) {
 		source,
 		snippet_renderers: new Map(),
 		snippets: new Set(),
-		async_deriveds: new Set(),
+		async_deriveds: new Map(),
 		pickled_awaits: new Set(),
 		instance_body: {
 			sync: [],
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/AwaitExpression.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/AwaitExpression.js
index 5a54d62471..c29f469ad0 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/AwaitExpression.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/AwaitExpression.js
@@ -1,6 +1,7 @@
 /** @import { AwaitExpression, Expression, SpreadElement, Property } from 'estree' */
 /** @import { Context } from '../types' */
 /** @import { AST } from '#compiler' */
+/** @import { ExpressionMetadata } from '../../nodes.js' */
 import * as e from '../../../errors.js';
 
 /**
@@ -10,15 +11,20 @@ import * as e from '../../../errors.js';
 export function AwaitExpression(node, context) {
 	const tla = context.state.ast_type === 'instance' && context.state.function_depth === 1;
 
-	// preserve context for awaits that precede other expressions in template or `$derived(...)`
 	if (
 		is_reactive_expression(
 			context.path,
 			context.state.derived_function_depth === context.state.function_depth
-		) &&
-		!is_last_evaluated_expression(context.path, node)
+		)
 	) {
-		context.state.analysis.pickled_awaits.add(node);
+		const expression = /** @type {ExpressionMetadata} */ (context.state.expression);
+
+		// preserve context for awaits that precede other expressions in template or `$derived(...)`,
+		// and for any await that follows one, so the restored context ends at the next suspension
+		if (expression.has_pickled_await || !is_last_evaluated_expression(context.path, node)) {
+			context.state.analysis.pickled_awaits.add(node);
+			expression.has_pickled_await = true;
+		}
 	}
 
 	let suspend = tla;
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js
index d3524af4db..312a93e5fd 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js
@@ -253,7 +253,7 @@ export function CallExpression(node, context) {
 		});
 
 		if (expression.has_await) {
-			context.state.analysis.async_deriveds.add(node);
+			context.state.analysis.async_deriveds.set(node, expression);
 		}
 
 		// Tell surrounding declaration tag about metadata for correct calculation of blockers etc
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/utils.js b/packages/svelte/src/compiler/phases/3-transform/client/utils.js
index d52b438d92..9cdfa5cae1 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/utils.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/utils.js
@@ -2,6 +2,7 @@
 /** @import { Binding } from '#compiler' */
 /** @import { ClientTransformState, ComponentClientTransformState } from './types.js' */
 /** @import { Analysis } from '../../types.js' */
+/** @import { ExpressionMetadata } from '../../nodes.js' */
 /** @import { Scope } from '../../scope.js' */
 import * as b from '#compiler/builders';
 import { is_simple_expression, save } from '../../../utils/ast.js';
@@ -164,20 +165,46 @@ export function should_proxy(node, scope) {
 	return true;
 }
 
+/**
+ * An async thunk. If an `await` inside restores the reaction context via `$.save`,
+ * the body exits through `$.unsave` so the context cannot leak into foreign microtasks
+ * that run before the returned promise settles
+ * @param {Expression | BlockStatement} body
+ * @param {ExpressionMetadata} metadata
+ */
+export function async_thunk(body, metadata) {
+	if (!metadata.has_pickled_await) {
+		return b.arrow([], body, true);
+	}
+
+	const block = body.type === 'BlockStatement' ? body : b.block([b.return(body)]);
+
+	return b.arrow(
+		[],
+		b.block([
+			{
+				type: 'TryStatement',
+				block,
+				handler: null,
+				finalizer: b.block([b.stmt(b.call('$.unsave'))])
+			}
+		]),
+		true
+	);
+}
+
 /**
  * Svelte legacy mode should use safe equals in most places, runes mode shouldn't
  * @param {ComponentClientTransformState} state
  * @param {Expression | BlockStatement} expression
- * @param {boolean} [async]
+ * @param {ExpressionMetadata} [metadata]
  */
-export function create_derived(state, expression, async = false) {
-	const thunk = b.thunk(expression, async);
-
-	if (async) {
-		return save(b.call('$.async_derived', thunk));
-	} else {
-		return b.call(state.analysis.runes ? '$.derived' : '$.derived_safe_equal', thunk);
+export function create_derived(state, expression, metadata) {
+	if (metadata?.has_await) {
+		return save(b.call('$.async_derived', async_thunk(expression, metadata)));
 	}
+
+	return b.call(state.analysis.runes ? '$.derived' : '$.derived_safe_equal', b.thunk(expression));
 }
 
 /**
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/AwaitBlock.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/AwaitBlock.js
index b8def178f2..986cd789d9 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/AwaitBlock.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/AwaitBlock.js
@@ -1,9 +1,9 @@
 /** @import { BlockStatement, Pattern, Statement } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { ComponentClientTransformState, ComponentContext } from '../types' */
-import { extract_identifiers, is_expression_async } from '../../../../utils/ast.js';
+import { extract_identifiers } from '../../../../utils/ast.js';
 import * as b from '#compiler/builders';
-import { create_derived } from '../utils.js';
+import { async_thunk, create_derived } from '../utils.js';
 import { get_value } from './shared/declarations.js';
 import { build_expression, add_svelte_meta } from './shared/utils.js';
 
@@ -15,10 +15,10 @@ export function AwaitBlock(node, context) {
 	context.state.template.push_comment();
 
 	// Visit {#await <expression>} first to ensure that scopes are in the correct order
-	const expression = b.thunk(
-		build_expression(context, node.expression, node.metadata.expression),
-		node.metadata.expression.has_await
-	);
+	const input = build_expression(context, node.expression, node.metadata.expression);
+	const expression = node.metadata.expression.has_await
+		? async_thunk(input, node.metadata.expression)
+		: b.thunk(input);
 
 	let then_block;
 	let catch_block;
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/ConstTag.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/ConstTag.js
index 63c84a507c..b3b2358e4c 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/ConstTag.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/ConstTag.js
@@ -19,7 +19,7 @@ export function ConstTag(node, context) {
 	if (declaration.id.type === 'Identifier') {
 		const init = build_expression(context, declaration.init, node.metadata.expression);
 
-		let expression = create_derived(context.state, init, node.metadata.expression.has_await);
+		let expression = create_derived(context.state, init, node.metadata.expression);
 
 		if (dev) {
 			expression = b.call('$.tag', expression, b.literal(declaration.id.name));
@@ -69,7 +69,7 @@ export function ConstTag(node, context) {
 					b.return(b.object(identifiers.map((node) => b.prop('init', node, node))))
 				]);
 
-		let expression = create_derived(context.state, block, node.metadata.expression.has_await);
+		let expression = create_derived(context.state, block, node.metadata.expression);
 
 		if (dev) {
 			expression = b.call('$.tag', expression, b.literal('[@const]'));
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/DeclarationTag.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/DeclarationTag.js
index abec5e828f..3f78b53c90 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/DeclarationTag.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/DeclarationTag.js
@@ -3,6 +3,7 @@
 /** @import { ComponentContext } from '../types' */
 import { extract_identifiers, has_await_expression } from '../../../../utils/ast.js';
 import * as b from '#compiler/builders';
+import { async_thunk } from '../utils.js';
 import { add_state_transformers } from './shared/declarations.js';
 
 /**
@@ -85,5 +86,5 @@ export function add_async_declaration(context, metadata, ids, assignments, kind
 		metadata.expression.has_await ||
 		assignments.some((assignment) => has_await_expression(assignment));
 	const body = assignments.length === 1 ? assignments[0].expression : b.block(assignments);
-	run.thunks.push(b.thunk(body, has_await));
+	run.thunks.push(has_await ? async_thunk(body, metadata.expression) : b.thunk(body));
 }
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/EachBlock.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/EachBlock.js
index b33eddd461..e0bd8d797a 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/EachBlock.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/EachBlock.js
@@ -12,6 +12,7 @@ import {
 import { dev } from '../../../../state.js';
 import { extract_paths, object } from '../../../../utils/ast.js';
 import * as b from '#compiler/builders';
+import { async_thunk } from '../utils.js';
 import { get_value } from './shared/declarations.js';
 import { build_expression, add_svelte_meta } from './shared/utils.js';
 
@@ -313,7 +314,9 @@ export function EachBlock(node, context) {
 
 	const has_await = node.metadata.expression.has_await;
 
-	const get_collection = b.thunk(collection, has_await);
+	const get_collection = has_await
+		? async_thunk(collection, node.metadata.expression)
+		: b.thunk(collection);
 	const thunk = has_await ? b.thunk(b.call('$.get', b.id('$$collection'))) : get_collection;
 
 	const render_args = [b.id('$$anchor'), item];
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/HtmlTag.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/HtmlTag.js
index 6c8b7c0354..910f0a1239 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/HtmlTag.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/HtmlTag.js
@@ -2,6 +2,7 @@
 /** @import { ComponentContext } from '../types' */
 import { is_ignored } from '../../../../state.js';
 import * as b from '#compiler/builders';
+import { async_thunk } from '../utils.js';
 import { build_expression } from './shared/utils.js';
 
 /**
@@ -46,7 +47,7 @@ export function HtmlTag(node, context) {
 					'$.async',
 					context.state.node,
 					node.metadata.expression.blockers(),
-					has_await ? b.array([b.thunk(expression, true)]) : b.void0,
+					has_await ? b.array([async_thunk(expression, node.metadata.expression)]) : b.void0,
 					b.arrow(
 						has_await ? [context.state.node, b.id('$$html')] : [context.state.node],
 						b.block([statement])
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/IfBlock.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/IfBlock.js
index b0cd51ce3f..5dcb3991c2 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/IfBlock.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/IfBlock.js
@@ -2,6 +2,7 @@
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types' */
 import * as b from '#compiler/builders';
+import { async_thunk } from '../utils.js';
 import { build_expression, add_svelte_meta } from './shared/utils.js';
 
 /**
@@ -117,7 +118,7 @@ export function IfBlock(node, context) {
 					'$.async',
 					context.state.node,
 					node.metadata.expression.blockers(),
-					has_await ? b.array([b.thunk(expression, true)]) : b.void0,
+					has_await ? b.array([async_thunk(expression, node.metadata.expression)]) : b.void0,
 					b.arrow(
 						has_await ? [context.state.node, b.id('$$condition')] : [context.state.node],
 						b.block(statements)
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/KeyBlock.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/KeyBlock.js
index 143a4e8edd..1831e7abab 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/KeyBlock.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/KeyBlock.js
@@ -2,6 +2,7 @@
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types' */
 import * as b from '#compiler/builders';
+import { async_thunk } from '../utils.js';
 import { build_expression, add_svelte_meta } from './shared/utils.js';
 
 /**
@@ -31,7 +32,7 @@ export function KeyBlock(node, context) {
 					'$.async',
 					context.state.node,
 					node.metadata.expression.blockers(),
-					has_await ? b.array([b.thunk(expression, true)]) : b.void0,
+					has_await ? b.array([async_thunk(expression, node.metadata.expression)]) : b.void0,
 					b.arrow(
 						has_await ? [context.state.node, b.id('$$key')] : [context.state.node],
 						b.block([statement])
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/SvelteElement.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/SvelteElement.js
index 10024298fa..909b4e0b71 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/SvelteElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/SvelteElement.js
@@ -4,6 +4,7 @@
 import { dev, locator } from '../../../../state.js';
 import { is_text_attribute } from '../../../../utils/ast.js';
 import * as b from '#compiler/builders';
+import { async_thunk } from '../utils.js';
 import { determine_namespace_for_children } from '../../utils.js';
 import {
 	build_attribute_value,
@@ -147,7 +148,7 @@ export function SvelteElement(node, context) {
 					'$.async',
 					context.state.node,
 					node.metadata.expression.blockers(),
-					has_await ? b.array([b.thunk(expression, true)]) : b.void0,
+					has_await ? b.array([async_thunk(expression, node.metadata.expression)]) : b.void0,
 					b.arrow(
 						has_await ? [context.state.node, b.id('$$tag')] : [context.state.node],
 						b.block(statements)
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
index b9f4690179..246feaccf6 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
@@ -6,7 +6,13 @@ import { extract_paths, save } from '../../../../utils/ast.js';
 import * as b from '#compiler/builders';
 import * as assert from '../../../../utils/assert.js';
 import { get_rune } from '../../../scope.js';
-import { get_prop_source, is_prop_source, is_state_source, should_proxy } from '../utils.js';
+import {
+	async_thunk,
+	get_prop_source,
+	is_prop_source,
+	is_state_source,
+	should_proxy
+} from '../utils.js';
 import { get_value } from './shared/declarations.js';
 
 /**
@@ -200,9 +206,10 @@ export function VariableDeclaration(node, context) {
 			}
 
 			if (rune === '$derived' || rune === '$derived.by') {
-				const is_async = context.state.analysis.async_deriveds.has(
+				const metadata = context.state.analysis.async_deriveds.get(
 					/** @type {CallExpression} */ (init)
 				);
+				const is_async = metadata !== undefined;
 
 				if (declarator.id.type === 'Identifier') {
 					let expression = /** @type {Expression} */ (context.visit(value));
@@ -213,7 +220,7 @@ export function VariableDeclaration(node, context) {
 						/** @type {Expression} */
 						let call = b.call(
 							'$.async_derived',
-							b.thunk(expression, true),
+							async_thunk(expression, metadata),
 							dev && b.literal(declarator.id.name),
 							location ? b.literal(location) : undefined
 						);
@@ -246,7 +253,7 @@ export function VariableDeclaration(node, context) {
 
 							call = b.call(
 								'$.async_derived',
-								b.thunk(expression, true),
+								async_thunk(expression, metadata),
 								dev &&
 									b.literal(
 										`[$derived ${declarator.id.type === 'ArrayPattern' ? 'iterable' : 'object'}]`
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js
index c305d53ea5..64ae573984 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js
@@ -8,7 +8,7 @@ import { sanitize_template_string } from '../../../../../utils/sanitize_template
 import { regex_is_valid_identifier } from '../../../../patterns.js';
 import is_reference from 'is-reference';
 import { dev, is_ignored, locator, component_name } from '../../../../../state.js';
-import { build_getter, is_state_source } from '../../utils.js';
+import { async_thunk, build_getter, is_state_source } from '../../utils.js';
 import { ExpressionMetadata } from '../../../../nodes.js';
 
 /**
@@ -16,10 +16,10 @@ import { ExpressionMetadata } from '../../../../nodes.js';
  * from templates and replacing them with `$0`, `$1` etc
  */
 export class Memoizer {
-	/** @type {Array<{ id: Identifier, expression: Expression }>} */
+	/** @type {Array<{ id: Identifier, expression: Expression, metadata: ExpressionMetadata }>} */
 	#sync = [];
 
-	/** @type {Array<{ id: Identifier, expression: Expression }>} */
+	/** @type {Array<{ id: Identifier, expression: Expression, metadata: ExpressionMetadata }>} */
 	#async = [];
 
 	/** @type {Set<Expression>} */
@@ -43,7 +43,7 @@ export class Memoizer {
 
 		const id = b.id('#'); // filled in later
 
-		(metadata.has_await ? this.#async : this.#sync).push({ id, expression });
+		(metadata.has_await ? this.#async : this.#sync).push({ id, expression, metadata });
 
 		return id;
 	}
@@ -84,7 +84,7 @@ export class Memoizer {
 		if (this.#async.length === 0) return;
 		// use `b.arrow` rather than `b.thunk` so that deferred async/template effects
 		// always read live bindings rather than a possibly stale snapshot.
-		return b.array(this.#async.map((memo) => b.arrow([], memo.expression, true)));
+		return b.array(this.#async.map((memo) => async_thunk(memo.expression, memo.metadata)));
 	}
 
 	sync_values() {
diff --git a/packages/svelte/src/compiler/phases/nodes.js b/packages/svelte/src/compiler/phases/nodes.js
index da7e73015b..fea447a7c5 100644
--- a/packages/svelte/src/compiler/phases/nodes.js
+++ b/packages/svelte/src/compiler/phases/nodes.js
@@ -77,6 +77,9 @@ export class ExpressionMetadata {
 	/** True if the expression contains `await` */
 	has_await = false;
 
+	/** True if an `await` restores the reaction context afterwards, so the thunk must end it */
+	has_pickled_await = false;
+
 	/** True if the expression includes a member expression */
 	has_member_expression = false;
 
@@ -142,6 +145,7 @@ export class ExpressionMetadata {
 		this.has_state ||= source.has_state;
 		this.has_call ||= source.has_call;
 		this.has_await ||= source.has_await;
+		this.has_pickled_await ||= source.has_pickled_await;
 		this.has_member_expression ||= source.has_member_expression;
 		this.has_assignment ||= source.has_assignment;
 		this.#blockers = null; // so that blockers are recalculated
diff --git a/packages/svelte/src/compiler/phases/types.d.ts b/packages/svelte/src/compiler/phases/types.d.ts
index a1a85ce145..38fa80ac4b 100644
--- a/packages/svelte/src/compiler/phases/types.d.ts
+++ b/packages/svelte/src/compiler/phases/types.d.ts
@@ -63,7 +63,7 @@ export interface Analysis {
 	accessors: boolean;
 
 	/** A set of deriveds that contain `await` expressions */
-	async_deriveds: Set<CallExpression>;
+	async_deriveds: Map<CallExpression, ExpressionMetadata>;
 	/** Awaits needing context preservation */
 	pickled_awaits: Set<AwaitExpression>;
 }
diff --git a/packages/svelte/src/internal/client/index.js b/packages/svelte/src/internal/client/index.js
index fa6f9dda39..6cdf81c155 100644
--- a/packages/svelte/src/internal/client/index.js
+++ b/packages/svelte/src/internal/client/index.js
@@ -103,6 +103,7 @@ export {
 	run,
 	save,
 	track_reactivity_loss,
+	unsave,
 	run_after_blockers,
 	wait
 } from './reactivity/async.js';
diff --git a/packages/svelte/src/internal/client/reactivity/async.js b/packages/svelte/src/internal/client/reactivity/async.js
index 2e7df92dc0..a75f97a54f 100644
--- a/packages/svelte/src/internal/client/reactivity/async.js
+++ b/packages/svelte/src/internal/client/reactivity/async.js
@@ -8,7 +8,6 @@ import {
 	set_component_context,
 	set_dev_stack
 } from '../context.js';
-import { Boundary } from '../dom/blocks/boundary.js';
 import { invoke_error_boundary } from '../error-handling.js';
 import {
 	active_effect,
@@ -25,7 +24,6 @@ import {
 	set_reactivity_loss_tracker
 } from './deriveds.js';
 import { aborted } from './effects.js';
-import { queue_micro_task } from '../dom/task.js';
 
 /**
  * @param {Blocker[]} blockers
@@ -156,6 +154,9 @@ export function capture() {
 	};
 }
 
+/** `true` between a `save` thunk restoring a context and the end of that synchronous segment */
+var restored = false;
+
 /**
  * Wraps an `await` expression in such a way that the effect context that was
  * active before the expression evaluated can be reapplied afterwards —
@@ -166,15 +167,32 @@ export function capture() {
  */
 export async function save(promise) {
 	var restore = capture();
+	// the context restored by an earlier `save` in this expression must not
+	// outlive the synchronous segment that is about to end at this `await`
+	unsave();
 	var value = await promise;
 
 	return () => {
 		restore();
-		queue_micro_task(unset_context);
+		restored = true;
 		return value;
 	};
 }
 
+/**
+ * Unset the context if a `save` thunk restored it in the current synchronous segment,
+ * so that a foreign microtask can never run inside a restored reaction context.
+ * Called at every suspension point, and at the end of async expression bodies —
+ * `async () => (await $.save(a))().b` becomes `async () => { try { return (await $.save(a))().b; } finally { $.unsave(); } }`
+ * @template T
+ * @param {T} [value]
+ * @returns {T}
+ */
+export function unsave(value) {
+	if (restored) unset_context();
+	return /** @type {T} */ (value);
+}
+
 /**
  * Reset `current_async_effect` after the `promise` resolves, so
  * that we can emit `await_reactivity_loss` warnings
@@ -183,6 +201,7 @@ export async function save(promise) {
  * @returns {Promise<() => T>}
  */
 export async function track_reactivity_loss(promise) {
+	unsave();
 	var previous_reactivity_loss_tracker = reactivity_loss_tracker;
 	// Ensure that unrelated reads after an async operation is kicked off don't cause false positives
 	queueMicrotask(() => {
@@ -269,6 +288,7 @@ export async function* for_await_track_reactivity_loss(iterable) {
 }
 
 export function unset_context(deactivate_batch = true) {
+	restored = false;
 	set_active_effect(null);
 	set_active_reaction(null);
 	set_component_context(null);
diff --git a/packages/svelte/tests/runtime-runes/samples/async-save-await-block-pending/_config.js b/packages/svelte/tests/runtime-runes/samples/async-save-await-block-pending/_config.js
new file mode 100644
index 0000000000..9608e294e7
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-save-await-block-pending/_config.js
@@ -0,0 +1,20 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['client'],
+	compileOptions: {
+		dev: true
+	},
+
+	async test({ assert, target, errors }) {
+		await new Promise((resolve) => setTimeout(resolve, 20));
+		await tick();
+
+		assert.deepEqual(
+			errors.filter((error) => error.includes('state_unsafe_mutation')),
+			[]
+		);
+		assert.htmlEqual(target.innerHTML, '<p>pending</p><p>1</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-save-await-block-pending/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-save-await-block-pending/main.svelte
new file mode 100644
index 0000000000..3545c69451
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-save-await-block-pending/main.svelte
@@ -0,0 +1,14 @@
+<script>
+	let foreign = $state(0);
+	const input = Promise.resolve({ pending: new Promise(() => {}) });
+
+	setTimeout(() => {
+		foreign += 1;
+	});
+</script>
+
+{#await (await input).pending}
+	<p>pending</p>
+{/await}
+
+<p>{foreign}</p>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-save-foreign-microtask-mutation-prod/_config.js b/packages/svelte/tests/runtime-runes/samples/async-save-foreign-microtask-mutation-prod/_config.js
new file mode 100644
index 0000000000..050ee60e09
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-save-foreign-microtask-mutation-prod/_config.js
@@ -0,0 +1,22 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['client'],
+
+	compileOptions: {
+		dev: false
+	},
+
+	async test({ assert, target, errors }) {
+		await tick();
+		await tick();
+		await tick();
+
+		assert.deepEqual(
+			errors.filter((error) => error.includes('state_unsafe_mutation')),
+			[]
+		);
+		assert.htmlEqual(target.innerHTML, '<p>4 1</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-save-foreign-microtask-mutation-prod/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-save-foreign-microtask-mutation-prod/main.svelte
new file mode 100644
index 0000000000..ef69eb1154
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-save-foreign-microtask-mutation-prod/main.svelte
@@ -0,0 +1,20 @@
+<script>
+	let foreign = $state(0);
+
+	const items = Promise.resolve([1, 2, 3]);
+	const one = Promise.resolve(1);
+
+	// lands the write while the derived is suspended on `await one`, after the
+	// context restored for `.length` — in production that await has no dev hook
+	items.then(() => {
+		queueMicrotask(() => {
+			queueMicrotask(() => {
+				foreign += 1;
+			});
+		});
+	});
+
+	const total = $derived((await items).length + (await one));
+</script>
+
+<p>{total} {foreign}</p>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-save-foreign-microtask-mutation/_config.js b/packages/svelte/tests/runtime-runes/samples/async-save-foreign-microtask-mutation/_config.js
new file mode 100644
index 0000000000..371cca3ff3
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-save-foreign-microtask-mutation/_config.js
@@ -0,0 +1,21 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['client'],
+
+	compileOptions: {
+		dev: true
+	},
+
+	async test({ assert, target, errors }) {
+		await tick();
+		await tick();
+
+		assert.deepEqual(
+			errors.filter((error) => error.includes('state_unsafe_mutation')),
+			[]
+		);
+		assert.htmlEqual(target.innerHTML, '<p>3 1</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-save-foreign-microtask-mutation/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-save-foreign-microtask-mutation/main.svelte
new file mode 100644
index 0000000000..c85206e7f1
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-save-foreign-microtask-mutation/main.svelte
@@ -0,0 +1,21 @@
+<script>
+	let foreign = $state(0);
+
+	const items = Promise.resolve([1, 2, 3]);
+
+	// registered before the derived, so it runs first when `items` settles.
+	// Two nested microtasks land the write in the window between the compiled
+	// continuation restoring the derived's context and svelte's queued unset
+	items.then(() => {
+		queueMicrotask(() => {
+			queueMicrotask(() => {
+				foreign += 1;
+			});
+		});
+	});
+
+	// `.length` follows the await, so the compiler pickles it via `$.save`
+	const length = $derived((await items).length);
+</script>
+
+<p>{length} {foreign}</p>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-save-throwing-expression/_config.js b/packages/svelte/tests/runtime-runes/samples/async-save-throwing-expression/_config.js
new file mode 100644
index 0000000000..5999daa5d2
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-save-throwing-expression/_config.js
@@ -0,0 +1,20 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['client'],
+	compileOptions: {
+		dev: true
+	},
+
+	async test({ assert, target, errors }) {
+		await tick();
+		await tick();
+
+		assert.deepEqual(
+			errors.filter((error) => error.includes('state_unsafe_mutation')),
+			[]
+		);
+		assert.htmlEqual(target.innerHTML, '<p>failed</p><p>1</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-save-throwing-expression/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-save-throwing-expression/main.svelte
new file mode 100644
index 0000000000..e94bf86568
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-save-throwing-expression/main.svelte
@@ -0,0 +1,26 @@
+<script>
+	let foreign = $state(0);
+	const input = Promise.resolve({
+		get value() {
+			throw new Error('boom');
+		}
+	});
+
+	input.then(() => {
+		queueMicrotask(() => {
+			queueMicrotask(() => {
+				foreign += 1;
+			});
+		});
+	});
+</script>
+
+<svelte:boundary onerror={() => {}}>
+	{#snippet failed()}
+		<p>failed</p>
+	{/snippet}
+
+	<p>{(await input).value}</p>
+</svelte:boundary>
+
+<p>{foreign}</p>
diff --git a/packages/svelte/tests/snapshot/samples/async-const/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-const/_expected/client/index.svelte.js
index 5c1d27ae54..b3e9e87aca 100644
--- a/packages/svelte/tests/snapshot/samples/async-const/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-const/_expected/client/index.svelte.js
@@ -14,7 +14,19 @@ export default function Async_const($$anchor) {
 			let b;
 
 			var promises = $.run([
-				async () => a = (await $.save($.async_derived(async () => (await $.save(1))())))(),
+				async () => {
+					try {
+						return a = (await $.save($.async_derived(async () => {
+							try {
+								return (await $.save(1))();
+							} finally {
+								$.unsave();
+							}
+						})))();
+					} finally {
+						$.unsave();
+					}
+				},
 				() => b = $.derived(() => $.get(a) + 1)
 			]);
 
diff --git a/packages/svelte/tests/snapshot/samples/async-if-chain/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-if-chain/_expected/client/index.svelte.js
index 8d21c2ceef..ca99d1c0c5 100644
--- a/packages/svelte/tests/snapshot/samples/async-if-chain/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-if-chain/_expected/client/index.svelte.js
@@ -90,52 +90,78 @@ export default function Async_if_chain($$anchor) {
 
 	var node_3 = $.sibling(node_1, 2);
 
-	$.async(node_3, [$$promises[0]], [async () => (await $.save(foo))() > 10], (node_3, $$condition) => {
-		var consequent_5 = ($$anchor) => {
-			var text_7 = $.text('foo');
-
-			$.append($$anchor, text_7);
-		};
-
-		var consequent_6 = ($$anchor) => {
-			var text_8 = $.text('bar');
-
-			$.append($$anchor, text_8);
-		};
-
-		var alternate_4 = ($$anchor) => {
-			var fragment_2 = $.comment();
-			var node_4 = $.first_child(fragment_2);
-
-			$.async(node_4, [$$promises[0]], [async () => (await $.save(foo))() > 5], (node_4, $$condition) => {
-				var consequent_7 = ($$anchor) => {
-					var text_9 = $.text('baz');
-
-					$.append($$anchor, text_9);
-				};
-
-				var alternate_3 = ($$anchor) => {
-					var text_10 = $.text('else');
-
-					$.append($$anchor, text_10);
-				};
-
-				$.if(
+	$.async(
+		node_3,
+		[$$promises[0]],
+		[
+			async () => {
+				try {
+					return (await $.save(foo))() > 10;
+				} finally {
+					$.unsave();
+				}
+			}
+		],
+		(node_3, $$condition) => {
+			var consequent_5 = ($$anchor) => {
+				var text_7 = $.text('foo');
+
+				$.append($$anchor, text_7);
+			};
+
+			var consequent_6 = ($$anchor) => {
+				var text_8 = $.text('bar');
+
+				$.append($$anchor, text_8);
+			};
+
+			var alternate_4 = ($$anchor) => {
+				var fragment_2 = $.comment();
+				var node_4 = $.first_child(fragment_2);
+
+				$.async(
 					node_4,
-					($$render) => {
-						if ($.get($$condition)) $$render(consequent_7); else $$render(alternate_3, -1);
-					},
-					true
+					[$$promises[0]],
+					[
+						async () => {
+							try {
+								return (await $.save(foo))() > 5;
+							} finally {
+								$.unsave();
+							}
+						}
+					],
+					(node_4, $$condition) => {
+						var consequent_7 = ($$anchor) => {
+							var text_9 = $.text('baz');
+
+							$.append($$anchor, text_9);
+						};
+
+						var alternate_3 = ($$anchor) => {
+							var text_10 = $.text('else');
+
+							$.append($$anchor, text_10);
+						};
+
+						$.if(
+							node_4,
+							($$render) => {
+								if ($.get($$condition)) $$render(consequent_7); else $$render(alternate_3, -1);
+							},
+							true
+						);
+					}
 				);
-			});
 
-			$.append($$anchor, fragment_2);
-		};
+				$.append($$anchor, fragment_2);
+			};
 
-		$.if(node_3, ($$render) => {
-			if ($.get($$condition)) $$render(consequent_5); else if (bar) $$render(consequent_6, 1); else $$render(alternate_4, -1);
-		});
-	});
+			$.if(node_3, ($$render) => {
+				if ($.get($$condition)) $$render(consequent_5); else if (bar) $$render(consequent_6, 1); else $$render(alternate_4, -1);
+			});
+		}
+	);
 
 	var node_5 = $.sibling(node_3, 2);
 
diff --git a/packages/svelte/tests/snapshot/samples/async-in-derived/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-in-derived/_expected/client/index.svelte.js
index 79b8ad0040..327dc4918c 100644
--- a/packages/svelte/tests/snapshot/samples/async-in-derived/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-in-derived/_expected/client/index.svelte.js
@@ -34,8 +34,34 @@ export default function Async_in_derived($$anchor, $$props) {
 			let no2;
 
 			var promises = $.run([
-				async () => yes1 = (await $.save($.async_derived(async () => (await $.save(1))())))(),
-				async () => yes2 = (await $.save($.async_derived(async () => foo((await $.save(1))()))))(),
+				async () => {
+					try {
+						return yes1 = (await $.save($.async_derived(async () => {
+							try {
+								return (await $.save(1))();
+							} finally {
+								$.unsave();
+							}
+						})))();
+					} finally {
+						$.unsave();
+					}
+				},
+
+				async () => {
+					try {
+						return yes2 = (await $.save($.async_derived(async () => {
+							try {
+								return foo((await $.save(1))());
+							} finally {
+								$.unsave();
+							}
+						})))();
+					} finally {
+						$.unsave();
+					}
+				},
+
 				() => no1 = $.derived(() => (async () => {
 					return await 1;
 				})()),

From 6f5dd04a0040db09c3171afd9d5e39071db6069d Mon Sep 17 00:00:00 2001
From: Ashok Kaushik <56879395+kaushikashok45@users.noreply.github.com>
Date: Tue, 25 Aug 2026 01:45:27 +0530
Subject: [PATCH 179/222] fix: Fixes error thrown on use of select with no
 options (#18449)

Fixes #18445.
---
 .changeset/every-rabbits-rule.md                             | 5 +++++
 .../phases/3-transform/client/visitors/shared/fragment.js    | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/every-rabbits-rule.md

diff --git a/.changeset/every-rabbits-rule.md b/.changeset/every-rabbits-rule.md
new file mode 100644
index 0000000000..e78df191a5
--- /dev/null
+++ b/.changeset/every-rabbits-rule.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: prevent malformed AST output for `<select>` with static `value` attribute
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/fragment.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/fragment.js
index f77af74f7e..38346e64b2 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/fragment.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/fragment.js
@@ -161,7 +161,7 @@ export function is_static_element(node) {
 		}
 
 		if (
-			['input', 'textarea'].includes(node.name) &&
+			['input', 'textarea', 'select'].includes(node.name) &&
 			['value', 'checked'].includes(attribute.name)
 		) {
 			return false;

From b20b2ee85eedc03670326d687fcf6afda07f01bf Mon Sep 17 00:00:00 2001
From: JY Wey <34165386+JaiWey@users.noreply.github.com>
Date: Tue, 25 Aug 2026 08:16:19 +1200
Subject: [PATCH 180/222] fix: avoid css tree-shaking for exported Snippet
 (#18540)

fix #16404

Currently one file can have multiple exports but only one `cssScopeTo` variable, which is hard coded to `default` inside vite-plugin-svelte.

Therefore set hasGlobal to `true` in case we export a snippet to not have this scoping enabled in v-p-s

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/three-peas-smoke.md                      |  5 +++++
 .../svelte/src/compiler/phases/2-analyze/index.js   |  5 +++++
 .../tests/css/samples/snippet-exported/_config.js   |  5 +++++
 .../tests/css/samples/snippet-exported/expected.css |  4 ++++
 .../tests/css/samples/snippet-exported/input.svelte | 13 +++++++++++++
 5 files changed, 32 insertions(+)
 create mode 100644 .changeset/three-peas-smoke.md
 create mode 100644 packages/svelte/tests/css/samples/snippet-exported/_config.js
 create mode 100644 packages/svelte/tests/css/samples/snippet-exported/expected.css
 create mode 100644 packages/svelte/tests/css/samples/snippet-exported/input.svelte

diff --git a/.changeset/three-peas-smoke.md b/.changeset/three-peas-smoke.md
new file mode 100644
index 0000000000..9a151c0046
--- /dev/null
+++ b/.changeset/three-peas-smoke.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: avoid css tree-shaking for exported Snippet
diff --git a/packages/svelte/src/compiler/phases/2-analyze/index.js b/packages/svelte/src/compiler/phases/2-analyze/index.js
index f6fb14a870..1cdd218ea8 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/index.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/index.js
@@ -832,6 +832,11 @@ export function analyze_component(root, source, options) {
 					} else {
 						e.export_undefined(specifier, name);
 					}
+				} else if (binding.initial?.type === 'SnippetBlock') {
+					// If a snippet is exported, a consumer could only import this named export and not the default export (the component).
+					// In this case we need to set hasGlobal of our output to true so that e.g. vite-plugin-svelte does not tell Vite to
+					// tree-shake the CSS if the default export is not used.
+					analysis.css.has_global = true;
 				}
 			}
 		}
diff --git a/packages/svelte/tests/css/samples/snippet-exported/_config.js b/packages/svelte/tests/css/samples/snippet-exported/_config.js
new file mode 100644
index 0000000000..30953854ad
--- /dev/null
+++ b/packages/svelte/tests/css/samples/snippet-exported/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	hasGlobal: true
+});
diff --git a/packages/svelte/tests/css/samples/snippet-exported/expected.css b/packages/svelte/tests/css/samples/snippet-exported/expected.css
new file mode 100644
index 0000000000..65d0c35e7c
--- /dev/null
+++ b/packages/svelte/tests/css/samples/snippet-exported/expected.css
@@ -0,0 +1,4 @@
+
+	.inner.svelte-xyz {
+		color: red;
+	}
diff --git a/packages/svelte/tests/css/samples/snippet-exported/input.svelte b/packages/svelte/tests/css/samples/snippet-exported/input.svelte
new file mode 100644
index 0000000000..3aef144e26
--- /dev/null
+++ b/packages/svelte/tests/css/samples/snippet-exported/input.svelte
@@ -0,0 +1,13 @@
+<script module>
+	export { outer };
+</script>
+
+{#snippet outer()}
+	<p class="inner"></p>
+{/snippet}
+
+<style>
+	.inner {
+		color: red;
+	}
+</style>

From fdb3aa8ba846a23e1bda47583507ac785e50f7e1 Mon Sep 17 00:00:00 2001
From: Mathias Picker <48158184+MathiasWP@users.noreply.github.com>
Date: Mon, 24 Aug 2026 22:46:50 +0200
Subject: [PATCH 181/222] perf: store setters cache as Set instead of Array
 (#18251)

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/setters-cache-set.md                      |  5 +++++
 .../src/internal/client/dom/elements/attributes.js   | 12 ++++++------
 2 files changed, 11 insertions(+), 6 deletions(-)
 create mode 100644 .changeset/setters-cache-set.md

diff --git a/.changeset/setters-cache-set.md b/.changeset/setters-cache-set.md
new file mode 100644
index 0000000000..2013446bc5
--- /dev/null
+++ b/.changeset/setters-cache-set.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+perf: store setters cache as `Set` instead of `Array`
diff --git a/packages/svelte/src/internal/client/dom/elements/attributes.js b/packages/svelte/src/internal/client/dom/elements/attributes.js
index 8a25be7acd..3d71abcd10 100644
--- a/packages/svelte/src/internal/client/dom/elements/attributes.js
+++ b/packages/svelte/src/internal/client/dom/elements/attributes.js
@@ -201,7 +201,7 @@ export function set_attribute(element, attribute, value, skip_warning) {
 
 	if (value == null) {
 		element.removeAttribute(attribute);
-	} else if (typeof value !== 'string' && get_setters(element).includes(attribute)) {
+	} else if (typeof value !== 'string' && get_setters(element).has(attribute)) {
 		// @ts-ignore
 		element[attribute] = value;
 	} else {
@@ -252,7 +252,7 @@ export function set_custom_element_data(node, prop, value) {
 			// customElements may not be available in browser extension contexts
 			!customElements ||
 			customElements.get(node.getAttribute('is') || node.nodeName.toLowerCase())
-				? get_setters(node).includes(prop)
+				? get_setters(node).has(prop)
 				: value && typeof value === 'object')
 		) {
 			// @ts-expect-error
@@ -473,7 +473,7 @@ function set_attributes(
 				}
 			} else if (
 				is_default ||
-				(setters.includes(name) && (is_custom_element || typeof value !== 'string'))
+				((is_custom_element || typeof value !== 'string') && setters.has(name))
 			) {
 				// @ts-ignore
 				element[name] = value;
@@ -582,7 +582,7 @@ function get_attributes(element) {
 	);
 }
 
-/** @type {Map<string, string[]>} */
+/** @type {Map<string, Set<string>>} */
 var setters_cache = new Map();
 
 /** @param {Element} element */
@@ -590,7 +590,7 @@ function get_setters(element) {
 	var cache_key = element.getAttribute('is') || element.nodeName;
 	var setters = setters_cache.get(cache_key);
 	if (setters) return setters;
-	setters_cache.set(cache_key, (setters = []));
+	setters_cache.set(cache_key, (setters = new Set()));
 
 	var descriptors;
 	var proto = element; // In the case of custom elements there might be setters on the instance
@@ -609,7 +609,7 @@ function get_setters(element) {
 				key !== 'textContent' &&
 				key !== 'innerText'
 			) {
-				setters.push(key);
+				setters.add(key);
 			}
 		}
 

From 2b740e496e857ae9e53bd15f5d5d7a2d4398139b Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Tue, 25 Aug 2026 04:14:43 -0400
Subject: [PATCH 182/222] fix: commit a reaction's dependencies even when it
 throws (#18703)

Fixes #18414 and a second bug with the same cause.

`update_reaction` in `runtime.js` commits a reaction's dependencies
after `fn()` returns: it swaps in `new_deps`, removes stale reactions
and registers the reaction into each new dep's `reactions`. When `fn()`
throws, the whole block is skipped. Two things go wrong from that.

A derived that the run read for the first time was already set
`CONNECTED` in `get` and registered itself into its own deps'
`reactions` during `update_derived`, but the throwing reaction never
registers as its reader. It sits in its deps' `reactions` with
`reactions === null` of its own, `remove_reaction`'s disconnect cascade
can never reach it, and it retains its `ctx`, closures and DOM past
component destruction and `unmount()`.

A derived that throws during its own run ends up with no dependencies at
all. It is not in its sources' `reactions`, so a later change to them
never re-runs it, and for an unowned derived `update_derived` then marks
the error value CLEAN because the derived has no deps. Anything reading
it keeps getting the first error forever.

The commit block is now `update_dependencies` and the `catch` calls it
before `handle_error`, so a failing reaction keeps the deps it read up
to the throw. That subscribes it to the inputs that produced the error,
and lets the normal disconnect cascade clean up when it is destroyed
(`Boundary.#handle_error` destroys the failed effect).

Co-authored-by: Randy Murphy <randalmurphal@users.noreply.github.com>
---
 .changeset/quiet-deriveds-unwind.md           |  5 ++
 .../svelte/src/internal/client/runtime.js     | 76 +++++++++++--------
 packages/svelte/tests/signals/test.ts         | 70 +++++++++++++++++
 3 files changed, 119 insertions(+), 32 deletions(-)
 create mode 100644 .changeset/quiet-deriveds-unwind.md

diff --git a/.changeset/quiet-deriveds-unwind.md b/.changeset/quiet-deriveds-unwind.md
new file mode 100644
index 0000000000..8036bdb781
--- /dev/null
+++ b/.changeset/quiet-deriveds-unwind.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: keep the dependencies of a reaction that throws, so deriveds it read are neither leaked nor stuck in their error
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index e0914b8f70..a881403f58 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -258,37 +258,7 @@ export function update_reaction(reaction) {
 		var fn = /** @type {Function} */ (reaction.fn);
 		var result = fn();
 		reaction.f |= REACTION_RAN;
-		var deps = reaction.deps;
-
-		// Don't remove reactions during fork;
-		// they must remain for when fork is discarded
-		var is_fork = current_batch?.is_fork;
-
-		if (new_deps !== null) {
-			var i;
-
-			if (!is_fork) {
-				remove_reactions(reaction, skipped_deps);
-			}
-
-			if (deps !== null && skipped_deps > 0) {
-				deps.length = skipped_deps + new_deps.length;
-				for (i = 0; i < new_deps.length; i++) {
-					deps[skipped_deps + i] = new_deps[i];
-				}
-			} else {
-				reaction.deps = deps = new_deps;
-			}
-
-			if (effect_tracking() && (reaction.f & CONNECTED) !== 0) {
-				for (i = skipped_deps; i < deps.length; i++) {
-					(deps[i].reactions ??= []).push(reaction);
-				}
-			}
-		} else if (!is_fork && deps !== null && skipped_deps < deps.length) {
-			remove_reactions(reaction, skipped_deps);
-			deps.length = skipped_deps;
-		}
+		var deps = update_dependencies(reaction);
 
 		// If we're inside an effect and we have untracked writes, then we need to
 		// ensure that if any of those untracked writes result in re-invalidation
@@ -300,7 +270,7 @@ export function update_reaction(reaction) {
 			deps !== null &&
 			(reaction.f & (DERIVED | MAYBE_DIRTY | DIRTY)) === 0
 		) {
-			for (i = 0; i < /** @type {Source[]} */ (untracked_writes).length; i++) {
+			for (var i = 0; i < /** @type {Source[]} */ (untracked_writes).length; i++) {
 				schedule_possible_effect_self_invalidation(
 					untracked_writes[i],
 					/** @type {Effect} */ (reaction)
@@ -344,6 +314,9 @@ export function update_reaction(reaction) {
 
 		return result;
 	} catch (error) {
+		// still commit the deps read before the throw, otherwise deriveds connected by this run keep no reader and the reaction never re-runs when they change
+		update_dependencies(reaction);
+
 		return handle_error(error);
 	} finally {
 		reaction.f ^= REACTION_IS_UPDATING;
@@ -358,6 +331,45 @@ export function update_reaction(reaction) {
 	}
 }
 
+/**
+ * @param {Reaction} reaction
+ */
+function update_dependencies(reaction) {
+	var deps = reaction.deps;
+
+	// Don't remove reactions during fork;
+	// they must remain for when fork is discarded
+	var is_fork = current_batch?.is_fork;
+
+	if (new_deps !== null) {
+		var i;
+
+		if (!is_fork) {
+			remove_reactions(reaction, skipped_deps);
+		}
+
+		if (deps !== null && skipped_deps > 0) {
+			deps.length = skipped_deps + new_deps.length;
+			for (i = 0; i < new_deps.length; i++) {
+				deps[skipped_deps + i] = new_deps[i];
+			}
+		} else {
+			reaction.deps = deps = new_deps;
+		}
+
+		if (effect_tracking() && (reaction.f & CONNECTED) !== 0) {
+			for (i = skipped_deps; i < deps.length; i++) {
+				(deps[i].reactions ??= []).push(reaction);
+			}
+		}
+	} else if (!is_fork && deps !== null && skipped_deps < deps.length) {
+		remove_reactions(reaction, skipped_deps);
+		deps.length = skipped_deps;
+	}
+
+	return deps;
+}
+
 /**
  * @template V
  * @param {Reaction} signal
diff --git a/packages/svelte/tests/signals/test.ts b/packages/svelte/tests/signals/test.ts
index 07f79bd395..c1ebc3ec75 100644
--- a/packages/svelte/tests/signals/test.ts
+++ b/packages/svelte/tests/signals/test.ts
@@ -1521,4 +1521,74 @@ describe('signals', () => {
 			assert.equal(s.reactions, null);
 		};
 	});
+
+	// https://github.com/sveltejs/svelte/issues/18414
+	test('a reaction that throws after first-reading a fresh derived does not leak it', () => {
+		const src = state(0);
+		const pane = derived(() => $.get(src));
+		const base = derived(() => $.get(pane) + ':base');
+		const extra = derived(() => $.get(pane) + ':extra');
+		const flag = state(false);
+
+		const destroy = effect_root(() => {
+			render_effect(() => {
+				if ($.get(flag)) {
+					$.get(extra);
+					throw new Error('render boom');
+				} else {
+					$.get(base);
+				}
+			});
+		});
+
+		return () => {
+			try {
+				flushSync(() => set(flag, true));
+			} catch {}
+
+			destroy();
+
+			assert.equal(src.reactions, null);
+		};
+	});
+
+	test('a derived that throws on its first run re-runs when its dependencies change', () => {
+		const s = state(0);
+		const fn = () => {
+			if ($.get(s) === 0) throw new Error('boom');
+			return $.get(s);
+		};
+		const owned = derived(fn);
+		const previous_effect = $.active_effect;
+		$.set_active_effect(null);
+		const unowned = derived(fn);
+		$.set_active_effect(previous_effect);
+		const log: any[] = [];
+
+		const destroy = effect_root(() => {
+			render_effect(() => {
+				for (const d of [owned, unowned]) {
+					try {
+						log.push($.get(d));
+					} catch {
+						log.push('error');
+					}
+				}
+			});
+		});
+
+		return () => {
+			assert.notEqual(owned.parent, null);
+			assert.equal(unowned.parent, null);
+
+			flushSync();
+			assert.deepEqual(log, ['error', 'error']);
+
+			flushSync(() => set(s, 1));
+			assert.deepEqual(log, ['error', 'error', 1, 1]);
+
+			destroy();
+			assert.equal(s.reactions, null);
+		};
+	});
 });

From 1b02aa28c8d746280617f59d6126b8b60f6cd748 Mon Sep 17 00:00:00 2001
From: Jawad Ali <contact.jawaddd@gmail.com>
Date: Tue, 25 Aug 2026 13:28:46 +0500
Subject: [PATCH 183/222] fix: decode uppercase-X hex numeric character
 references (#18708)

uppercase X is also valid per the HTML spec
---
 .changeset/uppercase-hex-entities.md                         | 5 +++++
 packages/svelte/src/compiler/phases/1-parse/utils/html.js    | 4 ++--
 .../tests/runtime-legacy/samples/html-entities/_config.js    | 1 +
 .../tests/runtime-legacy/samples/html-entities/main.svelte   | 1 +
 4 files changed, 9 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/uppercase-hex-entities.md

diff --git a/.changeset/uppercase-hex-entities.md b/.changeset/uppercase-hex-entities.md
new file mode 100644
index 0000000000..e6e13d5df5
--- /dev/null
+++ b/.changeset/uppercase-hex-entities.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: decode uppercase-`X` hex numeric character references (`&#X...;`)
diff --git a/packages/svelte/src/compiler/phases/1-parse/utils/html.js b/packages/svelte/src/compiler/phases/1-parse/utils/html.js
index a0c2a5b06f..1d660298c7 100644
--- a/packages/svelte/src/compiler/phases/1-parse/utils/html.js
+++ b/packages/svelte/src/compiler/phases/1-parse/utils/html.js
@@ -20,7 +20,7 @@ function reg_exp_entity(entity_name, is_attribute_value) {
 
 /** @param {boolean} is_attribute_value */
 function get_entity_pattern(is_attribute_value) {
-	const reg_exp_num = '#(?:x[a-fA-F\\d]+|\\d+)(?:;)?';
+	const reg_exp_num = '#(?:[xX][a-fA-F\\d]+|\\d+)(?:;)?';
 	const reg_exp_entities = Object.keys(entities).map(
 		/** @param {any} entity_name */ (entity_name) => reg_exp_entity(entity_name, is_attribute_value)
 	);
@@ -50,7 +50,7 @@ export function decode_character_references(html, is_attribute_value) {
 			// Handle named entities
 			if (entity[0] !== '#') {
 				code = entities[entity];
-			} else if (entity[1] === 'x') {
+			} else if (entity[1] === 'x' || entity[1] === 'X') {
 				code = parseInt(entity.substring(2), 16);
 			} else {
 				code = parseInt(entity.substring(1), 10);
diff --git a/packages/svelte/tests/runtime-legacy/samples/html-entities/_config.js b/packages/svelte/tests/runtime-legacy/samples/html-entities/_config.js
index add763989e..82c87495c4 100644
--- a/packages/svelte/tests/runtime-legacy/samples/html-entities/_config.js
+++ b/packages/svelte/tests/runtime-legacy/samples/html-entities/_config.js
@@ -7,6 +7,7 @@ export default test({
 		<span>*</span>
 		<span>*</span>
 		<span>*</span>
+		<span>*</span>
 
 		<span></span>
 		<span>A</span>
diff --git a/packages/svelte/tests/runtime-legacy/samples/html-entities/main.svelte b/packages/svelte/tests/runtime-legacy/samples/html-entities/main.svelte
index 2d0d66c939..25a60cb930 100644
--- a/packages/svelte/tests/runtime-legacy/samples/html-entities/main.svelte
+++ b/packages/svelte/tests/runtime-legacy/samples/html-entities/main.svelte
@@ -2,6 +2,7 @@
 <span>&midast;</span>
 <span>&#x0002A;</span>
 <span>&#x0002A</span>
+<span>&#X0002A;</span>
 <span>&#42;</span>
 
 <span>&#10;</span>

From 6b16b7f73fe8223ad7ab8bc629c98ba6d581f5cf Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Tue, 25 Aug 2026 04:35:46 -0400
Subject: [PATCH 184/222] fix: keep defaultChecked on hydrated radio inputs
 with spread attributes (#18701)

radio buttons were missing in the type check - remove the check instead (aligns with how we do it in the compiler, see `has_default_value_attribute`). Strictly speaking not fully correct but pragmatic solution that doesn't have any impact in practise

Needed by sveltejs/kit#16926.
---
 .changeset/keep-radio-default-checked.md      |  5 ++++
 .../client/dom/elements/attributes.js         |  7 ++----
 .../_config.js                                | 23 +++++++++++++++++++
 .../main.svelte                               |  9 ++++++++
 4 files changed, 39 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/keep-radio-default-checked.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/form-default-checked-radio-spread/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/form-default-checked-radio-spread/main.svelte

diff --git a/.changeset/keep-radio-default-checked.md b/.changeset/keep-radio-default-checked.md
new file mode 100644
index 0000000000..b3b32afda6
--- /dev/null
+++ b/.changeset/keep-radio-default-checked.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: keep `defaultChecked` on hydrated radio inputs with spread attributes
diff --git a/packages/svelte/src/internal/client/dom/elements/attributes.js b/packages/svelte/src/internal/client/dom/elements/attributes.js
index 3d71abcd10..69d4dd42a8 100644
--- a/packages/svelte/src/internal/client/dom/elements/attributes.js
+++ b/packages/svelte/src/internal/client/dom/elements/attributes.js
@@ -291,11 +291,8 @@ function set_attributes(
 	skip_warning = false
 ) {
 	if (hydrating && should_remove_defaults && element.nodeName === INPUT_TAG) {
-		var input = /** @type {HTMLInputElement} */ (element);
-		var attribute = input.type === 'checkbox' ? 'defaultChecked' : 'defaultValue';
-
-		if (!(attribute in next)) {
-			remove_input_defaults(input);
+		if (!('defaultValue' in next || 'defaultChecked' in next)) {
+			remove_input_defaults(/** @type {HTMLInputElement} */ (element));
 		}
 	}
 
diff --git a/packages/svelte/tests/runtime-runes/samples/form-default-checked-radio-spread/_config.js b/packages/svelte/tests/runtime-runes/samples/form-default-checked-radio-spread/_config.js
new file mode 100644
index 0000000000..3f3134ee7a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/form-default-checked-radio-spread/_config.js
@@ -0,0 +1,23 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['hydrate'],
+
+	async test({ assert, target }) {
+		const [a, b, reset] = target.querySelectorAll('input');
+
+		// let the deferred hydration cleanup run
+		await Promise.resolve();
+		flushSync();
+
+		b.checked = true;
+		reset.click();
+		await Promise.resolve();
+		flushSync();
+
+		assert.equal(a.defaultChecked, true);
+		assert.equal(a.checked, true);
+		assert.equal(b.checked, false);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/form-default-checked-radio-spread/main.svelte b/packages/svelte/tests/runtime-runes/samples/form-default-checked-radio-spread/main.svelte
new file mode 100644
index 0000000000..cb7ff0abd3
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/form-default-checked-radio-spread/main.svelte
@@ -0,0 +1,9 @@
+<script>
+	let spread = { defaultChecked: true, checked: true };
+</script>
+
+<form>
+	<input type="radio" name="option" value="a" {...spread} />
+	<input type="radio" name="option" value="b" />
+	<input type="reset" value="Reset" />
+</form>

From c894afd8c73e4f08a377909f29aa58177a256277 Mon Sep 17 00:00:00 2001
From: Jawad Ali <contact.jawaddd@gmail.com>
Date: Tue, 25 Aug 2026 13:37:34 +0500
Subject: [PATCH 185/222] fix: sync SvelteURL port when protocol setter clears
 it (#18705)

Per the WHATWG URL spec, assigning a new protocol can clear the URL's port when the current port equals the new scheme's default port. Therefore also `set` the port when the protocol is updated.
---
 .changeset/svelte-url-protocol-port.md     |  5 +++++
 packages/svelte/src/reactivity/url.js      |  2 ++
 packages/svelte/src/reactivity/url.test.ts | 22 ++++++++++++++++++++++
 3 files changed, 29 insertions(+)
 create mode 100644 .changeset/svelte-url-protocol-port.md

diff --git a/.changeset/svelte-url-protocol-port.md b/.changeset/svelte-url-protocol-port.md
new file mode 100644
index 0000000000..2c37fce4ab
--- /dev/null
+++ b/.changeset/svelte-url-protocol-port.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: sync `SvelteURL` port signal when the protocol setter clears the port
diff --git a/packages/svelte/src/reactivity/url.js b/packages/svelte/src/reactivity/url.js
index 549a20baa7..1e24e774ee 100644
--- a/packages/svelte/src/reactivity/url.js
+++ b/packages/svelte/src/reactivity/url.js
@@ -163,6 +163,8 @@ export class SvelteURL extends URL {
 	set protocol(value) {
 		super.protocol = value;
 		set(this.#protocol, super.protocol);
+		// changing the protocol can clear the port when it matches the new scheme's default
+		set(this.#port, super.port);
 	}
 
 	get search() {
diff --git a/packages/svelte/src/reactivity/url.test.ts b/packages/svelte/src/reactivity/url.test.ts
index d698116421..72518d730a 100644
--- a/packages/svelte/src/reactivity/url.test.ts
+++ b/packages/svelte/src/reactivity/url.test.ts
@@ -240,3 +240,25 @@ test('url.searchParams.forEach re-runs when the search string changes via the UR
 
 	cleanup();
 });
+
+test('url.port is updated when the protocol change clears the port', () => {
+	const url = new SvelteURL('http://example.com:443/');
+	const log: any = [];
+
+	const cleanup = effect_root(() => {
+		render_effect(() => {
+			log.push(url.port);
+		});
+	});
+
+	flushSync(() => {
+		// 443 is the default port for https, so it gets stripped
+		url.protocol = 'https:';
+	});
+
+	assert.equal(url.port, '');
+	assert.equal(url.href, 'https://example.com/');
+	assert.deepEqual(log, ['443', '']);
+
+	cleanup();
+});

From 135f1ec004352048454e732202c0bc8332816242 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Tue, 25 Aug 2026 11:24:45 +0200
Subject: [PATCH 186/222] fix: more robust rendering of Svelte custom element
 slots (#18710)

Instead of checking the given nodes at startup and only injecting those
into the inner Svelte component constructor, we are now detecting (via
the `$$host` property) whether or not the component is rendered as a
custom element, and in that case create all slots as real slots right
away.

Fixes #13638
Fixes #8997 (therefore closes #8999)
---
 .changeset/open-parents-stare.md              |  5 ++++
 .../src/internal/client/dom/blocks/slot.js    | 19 +++++++++++++
 .../$$slot-dynamic-content/_config.js         |  8 +++---
 .../html-slots/_config.js                     | 28 +++++++++++++++----
 .../no-shadow-dom/_config.js                  |  3 +-
 .../no-shadow-dom/main.svelte                 |  1 +
 6 files changed, 53 insertions(+), 11 deletions(-)
 create mode 100644 .changeset/open-parents-stare.md

diff --git a/.changeset/open-parents-stare.md b/.changeset/open-parents-stare.md
new file mode 100644
index 0000000000..cb94267ea0
--- /dev/null
+++ b/.changeset/open-parents-stare.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: more robust rendering of Svelte custom element slots
diff --git a/packages/svelte/src/internal/client/dom/blocks/slot.js b/packages/svelte/src/internal/client/dom/blocks/slot.js
index 10b2959582..491f04a5ea 100644
--- a/packages/svelte/src/internal/client/dom/blocks/slot.js
+++ b/packages/svelte/src/internal/client/dom/blocks/slot.js
@@ -1,4 +1,6 @@
 import { hydrate_next, hydrating } from '../hydration.js';
+import { create_element, create_text } from '../operations.js';
+import { append } from '../template.js';
 
 /**
  * @param {Comment} anchor
@@ -12,6 +14,23 @@ export function slot(anchor, $$props, name, slot_props, fallback_fn) {
 		hydrate_next();
 	}
 
+	// Custom element slots are native DOM slots.
+	// Use the stored reference because the shadow root may be closed.
+	if ($$props.$$host?.$$shadowRoot) {
+		const element = create_element('slot');
+		if (name !== 'default') element.name = name;
+
+		append(anchor, element);
+
+		if (fallback_fn !== null) {
+			const fallback_anchor = create_text();
+			element.append(fallback_anchor);
+			fallback_fn(fallback_anchor);
+		}
+
+		return;
+	}
+
 	var slot_fn = $$props.$$slots?.[name];
 	// Interop: Can use snippets to fill slots
 	var is_interop = false;
diff --git a/packages/svelte/tests/runtime-browser/custom-elements-samples/$$slot-dynamic-content/_config.js b/packages/svelte/tests/runtime-browser/custom-elements-samples/$$slot-dynamic-content/_config.js
index 8ade347a79..3fd5a09888 100644
--- a/packages/svelte/tests/runtime-browser/custom-elements-samples/$$slot-dynamic-content/_config.js
+++ b/packages/svelte/tests/runtime-browser/custom-elements-samples/$$slot-dynamic-content/_config.js
@@ -14,8 +14,8 @@ export default test({
 		assert.htmlEqual(
 			ce.shadowRoot.innerHTML,
 			`
-		<slot></slot>
-		<p>named fallback</p>
+		<slot>fallback</slot>
+		<slot name="named"><p>named fallback</p></slot>
 	`
 		);
 
@@ -23,8 +23,8 @@ export default test({
 		assert.htmlEqual(
 			ce.shadowRoot.innerHTML,
 			`
-		<slot></slot>
-		<p>named fallback</p>
+		<slot>fallback</slot>
+		<slot name="named"><p>named fallback</p></slot>
 	`
 		);
 	}
diff --git a/packages/svelte/tests/runtime-browser/custom-elements-samples/html-slots/_config.js b/packages/svelte/tests/runtime-browser/custom-elements-samples/html-slots/_config.js
index 287e2987b8..e3e8ce072b 100644
--- a/packages/svelte/tests/runtime-browser/custom-elements-samples/html-slots/_config.js
+++ b/packages/svelte/tests/runtime-browser/custom-elements-samples/html-slots/_config.js
@@ -3,10 +3,7 @@ const tick = () => Promise.resolve();
 
 export default test({
 	async test({ assert, target }) {
-		target.innerHTML = `
-		<custom-element>
-			<strong>slotted</strong>
-		</custom-element>`;
+		target.innerHTML = '<custom-element></custom-element>';
 		await tick();
 		await tick();
 
@@ -16,7 +13,26 @@ export default test({
 		const div = el.shadowRoot.children[0];
 		const [slot0, slot1] = div.children;
 
-		assert.equal(slot0.assignedNodes()[1], target.querySelector('strong'));
-		assert.equal(slot1.innerHTML, 'foo fallback content');
+		assert.equal(slot0.localName, 'slot');
+		assert.equal(slot0.assignedNodes().length, 0);
+		assert.equal(slot0.innerHTML, '<p>default fallback content</p>');
+		assert.equal(slot1.localName, 'slot');
+		assert.equal(slot1.name, 'foo');
+		assert.equal(slot1.assignedNodes().length, 0);
+		assert.equal(slot1.innerHTML, '<p>foo fallback content</p>');
+
+		const default_content = document.createElement('strong');
+		default_content.textContent = 'default content';
+		el.append(default_content);
+
+		const named_content = document.createElement('strong');
+		named_content.slot = 'foo';
+		named_content.textContent = 'named content';
+		el.append(named_content);
+
+		assert.equal(slot0.assignedNodes().length, 1);
+		assert.equal(slot0.assignedNodes()[0], default_content);
+		assert.equal(slot1.assignedNodes().length, 1);
+		assert.equal(slot1.assignedNodes()[0], named_content);
 	}
 });
diff --git a/packages/svelte/tests/runtime-browser/custom-elements-samples/no-shadow-dom/_config.js b/packages/svelte/tests/runtime-browser/custom-elements-samples/no-shadow-dom/_config.js
index cd8550120a..e83491418a 100644
--- a/packages/svelte/tests/runtime-browser/custom-elements-samples/no-shadow-dom/_config.js
+++ b/packages/svelte/tests/runtime-browser/custom-elements-samples/no-shadow-dom/_config.js
@@ -3,7 +3,7 @@ const tick = () => Promise.resolve();
 
 export default test({
 	async test({ assert, target }) {
-		target.innerHTML = '<custom-element name="world"></custom-element>';
+		target.innerHTML = '<custom-element name="world"><span>slotted</span></custom-element>';
 		await tick();
 		await tick();
 
@@ -15,5 +15,6 @@ export default test({
 		assert.equal(el.shadowRoot, null);
 		assert.equal(h1.innerHTML, 'Hello world!');
 		assert.equal(getComputedStyle(h1).color, 'rgb(255, 0, 0)');
+		assert.equal(el.querySelector('slot').innerHTML, '');
 	}
 });
diff --git a/packages/svelte/tests/runtime-browser/custom-elements-samples/no-shadow-dom/main.svelte b/packages/svelte/tests/runtime-browser/custom-elements-samples/no-shadow-dom/main.svelte
index 36fea3c43e..1c14fb98d8 100644
--- a/packages/svelte/tests/runtime-browser/custom-elements-samples/no-shadow-dom/main.svelte
+++ b/packages/svelte/tests/runtime-browser/custom-elements-samples/no-shadow-dom/main.svelte
@@ -5,6 +5,7 @@
 </script>
 
 <h1>Hello {name}!</h1>
+<slot>fallback</slot>
 
 <style>
 	h1 {

From 359413f5122bf866175e516141515c5387ad7743 Mon Sep 17 00:00:00 2001
From: Mathias Picker <48158184+MathiasWP@users.noreply.github.com>
Date: Tue, 25 Aug 2026 11:47:17 +0200
Subject: [PATCH 187/222] perf: treat `<img loading>` as a static element again
 (#18711)

Emits less code and skips two live DOM traversals per instance.

`is_static_element` treats `<img>` with a `loading` attribute as
non-static. That was added in #14237 so `RegularElement` could emit
`$.handle_lazy_img(node_id)`, which needed a reference to the element.
#15272 deleted `handle_lazy_img` (replaced by `importNode`) and removed
the call site, but left this check behind.


---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/tidy-owls-repeat.md                               | 5 +++++
 .../phases/3-transform/client/visitors/shared/fragment.js    | 5 -----
 .../skip-static-subtree/_expected/client/index.svelte.js     | 5 +----
 3 files changed, 6 insertions(+), 9 deletions(-)
 create mode 100644 .changeset/tidy-owls-repeat.md

diff --git a/.changeset/tidy-owls-repeat.md b/.changeset/tidy-owls-repeat.md
new file mode 100644
index 0000000000..2ef02e2051
--- /dev/null
+++ b/.changeset/tidy-owls-repeat.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+perf: treat `<img loading>` as a static element again
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/fragment.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/fragment.js
index 38346e64b2..72104481ec 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/fragment.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/fragment.js
@@ -171,11 +171,6 @@ export function is_static_element(node) {
 			return false;
 		}
 
-		// We need to apply src and loading after appending the img to the DOM for lazy loading to work
-		if (node.name === 'img' && attribute.name === 'loading') {
-			return false;
-		}
-
 		if (attribute.value !== true && !is_text_attribute(attribute)) {
 			return false;
 		}
diff --git a/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/client/index.svelte.js
index 78147659ff..85f7601bd7 100644
--- a/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/client/index.svelte.js
@@ -40,10 +40,7 @@ export default function Skip_static_subtree($$anchor, $$props) {
 
 	option.value = option.__value = 'a';
 	$.reset(select);
-
-	var img = $.sibling(select, 2);
-
-	$.next(2);
+	$.next(4);
 	$.template_effect(() => $.set_text(text, $$props.title));
 	$.append($$anchor, fragment);
 }
\ No newline at end of file

From 8299cbf11b266a561c822a7212526f3fbbadc53e Mon Sep 17 00:00:00 2001
From: Mathias Picker <48158184+MathiasWP@users.noreply.github.com>
Date: Tue, 25 Aug 2026 13:25:40 +0200
Subject: [PATCH 188/222] perf: use `$.comment()` for single comment templates
 (#18714)

Move the "single comment, we can make this faster" optimization into `transform_template` so all usage locations can benefit (e.g. select/option elements)

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/quiet-swans-invent.md              |  5 +++++
 .../client/transform-template/index.js        |  6 ++++++
 .../3-transform/client/visitors/Fragment.js   |  9 ++-------
 .../_expected/client/index.svelte.js          | 19 +++++++++----------
 4 files changed, 22 insertions(+), 17 deletions(-)
 create mode 100644 .changeset/quiet-swans-invent.md

diff --git a/.changeset/quiet-swans-invent.md b/.changeset/quiet-swans-invent.md
new file mode 100644
index 0000000000..3b35a933d5
--- /dev/null
+++ b/.changeset/quiet-swans-invent.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+perf: use `$.comment()` for single-comment templates
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/transform-template/index.js b/packages/svelte/src/compiler/phases/3-transform/client/transform-template/index.js
index 5fdc88844b..4c6d5f4ece 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/transform-template/index.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/transform-template/index.js
@@ -39,6 +39,12 @@ export function transform_template(state, name, flags = 0) {
 	const namespace = state.metadata.namespace;
 	const tree = state.options.fragments === 'tree';
 
+	const { nodes } = state.template;
+	const is_lone_anchor = nodes.length === 1 && nodes[0].type === 'comment';
+
+	// special case - `$.comment` creates the anchor more cheaply than cloning a template
+	if (is_lone_anchor) return b.id('$.comment');
+
 	const expression = tree ? state.template.as_tree() : state.template.as_html();
 
 	const key =
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/Fragment.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/Fragment.js
index 893b1db568..1272290c4a 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/Fragment.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/Fragment.js
@@ -141,14 +141,9 @@ export function Fragment(node, context) {
 				flags |= TEMPLATE_USE_IMPORT_NODE;
 			}
 
-			if (state.template.nodes.length === 1 && state.template.nodes[0].type === 'comment') {
-				// special case — we can use `$.comment` instead of creating a unique template
-				state.init.unshift(b.var(id, b.call('$.comment')));
-			} else {
-				const template_name = transform_template(state, 'root', flags);
+			const template_name = transform_template(state, 'root', flags);
 
-				state.init.unshift(b.var(id, b.call(template_name)));
-			}
+			state.init.unshift(b.var(id, b.call(template_name)));
 
 			close = b.stmt(b.call('$.append', b.id('$$anchor'), id));
 		}
diff --git a/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js
index c8354fe67e..fbeecbafb3 100644
--- a/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js
@@ -35,7 +35,6 @@ var option_content = $.from_html(`<span>Rich</span>`, 1);
 var root_4 = $.from_html(`<option> </option>`);
 var root_5 = $.from_html(`<option>Visible</option>`);
 var root_6 = $.from_html(`<option>Keyed</option>`);
-var select_content = $.from_html(`<!>`, 1);
 var option_content_1 = $.from_html(`<strong>Bold</strong>`, 1);
 var option_content_2 = $.from_html(`<em>Italic</em> text`, 1);
 var option_content_3 = $.from_html(`<span> </span>`, 1);
@@ -116,7 +115,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.customizable_select(select_4, () => {
 		var anchor_1 = $.child(select_4);
-		var fragment_2 = select_content();
+		var fragment_2 = $.comment();
 		var node_2 = $.first_child(fragment_2);
 
 		opt(node_2);
@@ -291,7 +290,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.customizable_select(select_13, () => {
 		var anchor_6 = $.child(select_13);
-		var fragment_8 = select_content();
+		var fragment_8 = $.comment();
 		var node_7 = $.first_child(fragment_8);
 
 		Option(node_7, {});
@@ -302,7 +301,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.customizable_select(select_14, () => {
 		var anchor_7 = $.child(select_14);
-		var fragment_9 = select_content();
+		var fragment_9 = $.comment();
 		var node_8 = $.first_child(fragment_9);
 
 		option_snippet(node_8);
@@ -313,7 +312,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.customizable_select(select_15, () => {
 		var anchor_8 = $.child(select_15);
-		var fragment_10 = select_content();
+		var fragment_10 = $.comment();
 		var node_9 = $.first_child(fragment_10);
 
 		$.html(node_9, () => html);
@@ -325,7 +324,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.customizable_select(optgroup_2, () => {
 		var anchor_9 = $.child(optgroup_2);
-		var fragment_11 = select_content();
+		var fragment_11 = $.comment();
 		var node_10 = $.first_child(fragment_11);
 
 		Option(node_10, {});
@@ -339,7 +338,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.customizable_select(optgroup_3, () => {
 		var anchor_10 = $.child(optgroup_3);
-		var fragment_12 = select_content();
+		var fragment_12 = $.comment();
 		var node_11 = $.first_child(fragment_12);
 
 		option_snippet2(node_11);
@@ -353,7 +352,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.customizable_select(option_16, () => {
 		var anchor_11 = $.child(option_16);
-		var fragment_13 = select_content();
+		var fragment_13 = $.comment();
 		var node_12 = $.first_child(fragment_13);
 
 		$.html(node_12, () => '<strong>Bold HTML</strong>');
@@ -366,7 +365,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.customizable_select(select_19, () => {
 		var anchor_12 = $.child(select_19);
-		var fragment_14 = select_content();
+		var fragment_14 = $.comment();
 		var node_13 = $.first_child(fragment_14);
 
 		$.each(node_13, 1, () => items, $.index, ($$anchor, item) => {
@@ -380,7 +379,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.customizable_select(select_20, () => {
 		var anchor_13 = $.child(select_20);
-		var fragment_16 = select_content();
+		var fragment_16 = $.comment();
 		var node_14 = $.first_child(fragment_16);
 
 		{

From 6b99f9fb52ae8db0f1d7f28b4cbdbcc2f4187a34 Mon Sep 17 00:00:00 2001
From: Mathias Picker <48158184+MathiasWP@users.noreply.github.com>
Date: Tue, 25 Aug 2026 13:26:32 +0200
Subject: [PATCH 189/222] perf: reuse the cached value in the
 `<option>`/`<select>` value guard (#18713)

One fewer evaluation of the value expression per update.

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/eighty-moons-happen.md             |  5 ++
 .../client/visitors/RegularElement.js         | 53 +++++++++++--------
 .../_expected/client/index.svelte.js          |  8 +--
 3 files changed, 40 insertions(+), 26 deletions(-)
 create mode 100644 .changeset/eighty-moons-happen.md

diff --git a/.changeset/eighty-moons-happen.md b/.changeset/eighty-moons-happen.md
new file mode 100644
index 0000000000..94fb3d313d
--- /dev/null
+++ b/.changeset/eighty-moons-happen.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+perf: reuse the cached value in the `<option>`/`<select>` value guard
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
index de09d3ef60..ab15d55670 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
@@ -701,28 +701,32 @@ function build_element_special_value_attribute(
 	);
 
 	const evaluated = context.state.scope.evaluate(value);
-	const assignment = b.assignment('=', b.member(node_id, '__value'), value);
 
-	const set_value_assignment = b.assignment(
-		'=',
-		b.member(node_id, 'value'),
-		evaluated.is_defined ? assignment : b.logical('??', assignment, b.literal(''))
-	);
+	/** @param {Expression} value */
+	const build_update = (value) => {
+		const assignment = b.assignment('=', b.member(node_id, '__value'), value);
 
-	const update = b.stmt(
-		is_select_with_value
-			? b.sequence([
-					set_value_assignment,
-					// This ensures a one-way street to the DOM in case it's <select {value}>
-					// and not <select bind:value>. We need it in addition to $.init_select
-					// because the select value is not reflected as an attribute, so the
-					// mutation observer wouldn't notice.
-					b.call('$.select_option', node_id, value)
-				])
-			: synthetic
-				? assignment
-				: set_value_assignment
-	);
+		const set_value_assignment = b.assignment(
+			'=',
+			b.member(node_id, 'value'),
+			evaluated.is_defined ? assignment : b.logical('??', assignment, b.literal(''))
+		);
+
+		return b.stmt(
+			is_select_with_value
+				? b.sequence([
+						set_value_assignment,
+						// This ensures a one-way street to the DOM in case it's <select {value}>
+						// and not <select bind:value>. We need it in addition to $.init_select
+						// because the select value is not reflected as an attribute, so the
+						// mutation observer wouldn't notice.
+						b.call('$.select_option', node_id, value)
+					])
+				: synthetic
+					? assignment
+					: set_value_assignment
+		);
+	};
 
 	if (has_state) {
 		const id = b.id(state.scope.generate(`${node_id.name}_value`));
@@ -733,9 +737,14 @@ function build_element_special_value_attribute(
 		const init = element === 'option' ? b.object([]) : undefined;
 
 		state.init.push(b.var(id, init));
-		state.update.push(b.if(b.binary('!==', id, b.assignment('=', id, value)), b.block([update])));
+
+		// the guard already evaluated `value` into `id`, so read that back rather than
+		// evaluating the same expression (and its signal reads) a second time
+		state.update.push(
+			b.if(b.binary('!==', id, b.assignment('=', id, value)), b.block([build_update(id)]))
+		);
 	} else {
-		state.init.push(update);
+		state.init.push(build_update(value));
 	}
 
 	if (is_select_with_value) {
diff --git a/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js
index fbeecbafb3..f24736e931 100644
--- a/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js
@@ -74,7 +74,7 @@ export default function Select_with_rich_content($$anchor) {
 			$.set_text(text, $.get(item));
 
 			if (option_5_value !== (option_5_value = $.get(item))) {
-				option_5.__value = $.get(item);
+				option_5.__value = option_5_value;
 			}
 		});
 
@@ -137,7 +137,7 @@ export default function Select_with_rich_content($$anchor) {
 			$.set_text(text_1, $.get(x));
 
 			if (option_8_value !== (option_8_value = $.get(x))) {
-				option_8.__value = $.get(x);
+				option_8.__value = option_8_value;
 			}
 		});
 
@@ -175,7 +175,7 @@ export default function Select_with_rich_content($$anchor) {
 			$.set_text(text_2, $.get(item));
 
 			if (option_10_value !== (option_10_value = $.get(item))) {
-				option_10.__value = $.get(item);
+				option_10.__value = option_10_value;
 			}
 		});
 
@@ -240,7 +240,7 @@ export default function Select_with_rich_content($$anchor) {
 					$.set_text(text_4, $.get(item));
 
 					if (option_13_value !== (option_13_value = $.get(item))) {
-						option_13.__value = $.get(item);
+						option_13.__value = option_13_value;
 					}
 				});
 

From 34489c10df97de6af941a1c21b0cadbc85bfd7cf Mon Sep 17 00:00:00 2001
From: Mathias Picker <48158184+MathiasWP@users.noreply.github.com>
Date: Tue, 25 Aug 2026 14:13:21 +0200
Subject: [PATCH 190/222] perf: emit `$.only_child` for elements with a single
 child (#18717)

`<p>{text}</p>` and friends compile to `var x = $.child(p, true);
$.reset(p);`. Across the 4,020 components in `packages/svelte/tests`,
that exact pair occurs 1,885 times, more than any other adjacent
statement pair.

`$.only_child` does both, reducing the number of statements in the compiled output
---
 .changeset/olive-pugs-shake.md                |  5 +++
 .../client/visitors/RegularElement.js         | 40 ++++++++++++++++++-
 .../src/internal/client/dom/operations.js     | 22 +++++++++-
 packages/svelte/src/internal/client/index.js  |  1 +
 .../_expected/client/index.svelte.js          |  3 +-
 .../_expected/client/index.svelte.js          |  3 +-
 .../_expected/client/index.svelte.js          |  5 +--
 .../_expected/client/index.svelte.js          |  5 +--
 .../_expected/client/index.svelte.js          | 23 +++--------
 .../_expected/client/index.svelte.js          |  5 +--
 .../_expected/client/index.svelte.js          |  3 +-
 11 files changed, 76 insertions(+), 39 deletions(-)
 create mode 100644 .changeset/olive-pugs-shake.md

diff --git a/.changeset/olive-pugs-shake.md b/.changeset/olive-pugs-shake.md
new file mode 100644
index 0000000000..abd0db2152
--- /dev/null
+++ b/.changeset/olive-pugs-shake.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+perf: emit `$.only_child` for elements with a single child
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
index ab15d55670..4c1538c331 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
@@ -1,4 +1,4 @@
-/** @import { ArrayExpression, Expression, ExpressionStatement, Identifier, MemberExpression, ObjectExpression } from 'estree' */
+/** @import { ArrayExpression, Expression, ExpressionStatement, Identifier, MemberExpression, ObjectExpression, Statement } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { ComponentClientTransformState, ComponentContext } from '../types' */
 /** @import { Scope } from '../../../scope' */
@@ -432,7 +432,7 @@ export function RegularElement(node, context) {
 			state: child_state
 		});
 
-		if (needs_reset) {
+		if (needs_reset && !fold_reset_into_child(child_state.init, context.state.node)) {
 			child_state.init.push(b.stmt(b.call('$.reset', context.state.node)));
 		}
 	}
@@ -751,3 +751,39 @@ function build_element_special_value_attribute(
 		state.init.push(b.stmt(b.call('$.init_select', node_id)));
 	}
 }
+
+/**
+ * `<p>{text}</p>` and friends produce `var x = $.child(p, true); $.reset(p);`. That pair is
+ * by far the most common shape in compiled output, and `$.only_child` does both, so fold the
+ * two together when the `$.child(...)` is the last thing we emitted for this element.
+ * @param {Statement[]} init
+ * @param {Expression} node_id
+ * @returns {boolean} whether the reset was folded in
+ */
+function fold_reset_into_child(init, node_id) {
+	const last = init.at(-1);
+
+	if (
+		node_id?.type !== 'Identifier' ||
+		last?.type !== 'VariableDeclaration' ||
+		last.declarations.length !== 1
+	) {
+		return false;
+	}
+
+	const call = last.declarations[0].init;
+
+	if (
+		call?.type !== 'CallExpression' ||
+		call.callee.type !== 'Identifier' ||
+		call.callee.name !== '$.child' ||
+		call.arguments[0]?.type !== 'Identifier' ||
+		call.arguments[0].name !== node_id.name
+	) {
+		return false;
+	}
+
+	call.callee = b.id('$.only_child');
+
+	return true;
+}
diff --git a/packages/svelte/src/internal/client/dom/operations.js b/packages/svelte/src/internal/client/dom/operations.js
index bc12a0b07e..21b5ee4ecb 100644
--- a/packages/svelte/src/internal/client/dom/operations.js
+++ b/packages/svelte/src/internal/client/dom/operations.js
@@ -1,5 +1,5 @@
 /** @import { Effect, TemplateNode } from '#client' */
-import { hydrate_node, hydrating, set_hydrate_node } from './hydration.js';
+import { hydrate_node, hydrating, reset, set_hydrate_node } from './hydration.js';
 import { DEV } from 'esm-env';
 import { init_array_prototype_warnings } from '../dev/equality.js';
 import { get_descriptor, is_extensible } from '../../shared/utils.js';
@@ -165,6 +165,26 @@ export function first_child(node, is_text = false) {
 	return hydrate_node;
 }
 
+/**
+ * `child`, for the very common case of an element with exactly one child. Resetting the
+ * hydration cursor is part of the same step, so the compiler doesn't have to emit a
+ * separate `reset` call for every `<p>{text}</p>` in an app.
+ * Don't mark this as side-effect-free, hydration needs to walk all nodes
+ * @param {TemplateNode} node
+ * @param {boolean} [is_text]
+ * @returns {TemplateNode | null}
+ */
+export function only_child(node, is_text = false) {
+	if (!hydrating) {
+		return get_first_child(node);
+	}
+
+	var first = child(node, is_text);
+	reset(node);
+
+	return first;
+}
+
 /**
  * Don't mark this as side-effect-free, hydration needs to walk all nodes
  * @param {TemplateNode} node
diff --git a/packages/svelte/src/internal/client/index.js b/packages/svelte/src/internal/client/index.js
index 6cdf81c155..8c922b0b84 100644
--- a/packages/svelte/src/internal/client/index.js
+++ b/packages/svelte/src/internal/client/index.js
@@ -164,6 +164,7 @@ export { proxy } from './proxy.js';
 export { create_custom_element } from './dom/elements/custom-element.js';
 export {
 	child,
+	only_child,
 	first_child,
 	sibling,
 	$window as window,
diff --git a/packages/svelte/tests/snapshot/samples/async-const/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-const/_expected/client/index.svelte.js
index b3e9e87aca..41ab26212c 100644
--- a/packages/svelte/tests/snapshot/samples/async-const/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-const/_expected/client/index.svelte.js
@@ -31,9 +31,8 @@ export default function Async_const($$anchor) {
 			]);
 
 			var p = root();
-			var text = $.child(p, true);
+			var text = $.only_child(p, true);
 
-			$.reset(p);
 			$.template_effect(() => $.set_text(text, $.get(b)), void 0, void 0, [promises[1]]);
 			$.append($$anchor, p);
 		};
diff --git a/packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/_expected/client/index.svelte.js
index 668c936e4e..c5b700ffec 100644
--- a/packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/_expected/client/index.svelte.js
@@ -8,9 +8,8 @@ export default function Async_top_level_inspect_server($$anchor) {
 	var data;
 	var $$promises = $.run([async () => data = await Promise.resolve(42), () => void 0]);
 	var p = root();
-	var text = $.child(p, true);
+	var text = $.only_child(p, true);
 
-	$.reset(p);
 	$.template_effect(() => $.set_text(text, data), void 0, void 0, [$$promises[1]]);
 	$.append($$anchor, p);
 }
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/await-block-scope/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/await-block-scope/_expected/client/index.svelte.js
index e1b87d6280..7097ec24d9 100644
--- a/packages/svelte/tests/snapshot/samples/await-block-scope/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/await-block-scope/_expected/client/index.svelte.js
@@ -13,10 +13,7 @@ export default function Await_block_scope($$anchor) {
 
 	var fragment = root();
 	var button = $.first_child(fragment);
-	var text = $.child(button);
-
-	$.reset(button);
-
+	var text = $.only_child(button);
 	var node = $.sibling(button, 2);
 
 	$.await(node, () => $.get(promise), null, ($$anchor, counter) => {});
diff --git a/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/client/index.svelte.js
index 837a7cd65a..8fe9663290 100644
--- a/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/client/index.svelte.js
@@ -16,10 +16,7 @@ export default function Nullish_coallescence_omittance($$anchor, $$props) {
 	b.textContent = '123';
 
 	var button = $.sibling(b, 2);
-	var text = $.child(button);
-
-	$.reset(button);
-
+	var text = $.only_child(button);
 	var h1_1 = $.sibling(button, 2);
 
 	h1_1.textContent = 'Hello, world';
diff --git a/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js
index f24736e931..36b774340b 100644
--- a/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js
@@ -64,10 +64,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.each(select_1, 5, () => items, $.index, ($$anchor, item) => {
 		var option_5 = root_4();
-		var text = $.child(option_5, true);
-
-		$.reset(option_5);
-
+		var text = $.only_child(option_5, true);
 		var option_5_value = {};
 
 		$.template_effect(() => {
@@ -127,10 +124,7 @@ export default function Select_with_rich_content($$anchor) {
 	$.each(select_5, 5, () => items, $.index, ($$anchor, item) => {
 		const x = $.derived_safe_equal(() => $.get(item) * 2);
 		var option_8 = root_4();
-		var text_1 = $.child(option_8, true);
-
-		$.reset(option_8);
-
+		var text_1 = $.only_child(option_8, true);
 		var option_8_value = {};
 
 		$.template_effect(() => {
@@ -165,10 +159,7 @@ export default function Select_with_rich_content($$anchor) {
 
 	$.each(optgroup_1, 5, () => items, $.index, ($$anchor, item) => {
 		var option_10 = root_4();
-		var text_2 = $.child(option_10, true);
-
-		$.reset(option_10);
-
+		var text_2 = $.only_child(option_10, true);
 		var option_10_value = {};
 
 		$.template_effect(() => {
@@ -208,9 +199,8 @@ export default function Select_with_rich_content($$anchor) {
 			var anchor_4 = $.child(option_12);
 			var fragment_5 = option_content_3();
 			var span = $.first_child(fragment_5);
-			var text_3 = $.child(span, true);
+			var text_3 = $.only_child(span, true);
 
-			$.reset(span);
 			$.template_effect(() => $.set_text(text_3, $.get(item)));
 			$.append(anchor_4, fragment_5);
 		});
@@ -230,10 +220,7 @@ export default function Select_with_rich_content($$anchor) {
 
 			$.each(node_4, 1, () => items, $.index, ($$anchor, item) => {
 				var option_13 = root_4();
-				var text_4 = $.child(option_13, true);
-
-				$.reset(option_13);
-
+				var text_4 = $.only_child(option_13, true);
 				var option_13_value = {};
 
 				$.template_effect(() => {
diff --git a/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/client/index.svelte.js
index 85f7601bd7..30976b40e6 100644
--- a/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/client/index.svelte.js
@@ -7,10 +7,7 @@ export default function Skip_static_subtree($$anchor, $$props) {
 	var fragment = root();
 	var main = $.sibling($.first_child(fragment), 2);
 	var h1 = $.child(main);
-	var text = $.child(h1, true);
-
-	$.reset(h1);
-
+	var text = $.only_child(h1, true);
 	var node = $.sibling(h1, 10);
 
 	$.html(node, () => $$props.content);
diff --git a/packages/svelte/tests/snapshot/samples/text-nodes-deriveds/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/text-nodes-deriveds/_expected/client/index.svelte.js
index 4148a546c8..a6a38f475c 100644
--- a/packages/svelte/tests/snapshot/samples/text-nodes-deriveds/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/text-nodes-deriveds/_expected/client/index.svelte.js
@@ -16,9 +16,8 @@ export default function Text_nodes_deriveds($$anchor) {
 	}
 
 	var p = root();
-	var text = $.child(p);
+	var text = $.only_child(p);
 
-	$.reset(p);
 	$.template_effect(($0, $1) => $.set_text(text, `${$0 ?? ''}${$1 ?? ''}`), [() => text1(), () => text2()]);
 	$.append($$anchor, p);
 }
\ No newline at end of file

From b433f3cd878814d6d141be359e5dafa9959b5f9e Mon Sep 17 00:00:00 2001
From: Bao Nguyen <39545125+giaBaoJS@users.noreply.github.com>
Date: Tue, 25 Aug 2026 19:22:56 +0700
Subject: [PATCH 191/222] fix: preserve line feed character references in
 attribute values (#18691)

Fixes #15555

Pass on whether we're in an attribute to not replace the charcode with the whitespace charcode in that case
---
 .changeset/tricky-donkeys-clap.md             |  5 ++
 .../src/compiler/phases/1-parse/utils/html.js | 15 ++++--
 .../convert-entities-line-feed/input.svelte   |  1 +
 .../convert-entities-line-feed/output.json    | 53 +++++++++++++++++++
 .../html-entity-line-feed/Component.svelte    |  5 ++
 .../samples/html-entity-line-feed/_config.js  | 15 ++++++
 .../samples/html-entity-line-feed/main.svelte |  9 ++++
 7 files changed, 98 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/tricky-donkeys-clap.md
 create mode 100644 packages/svelte/tests/parser-legacy/samples/convert-entities-line-feed/input.svelte
 create mode 100644 packages/svelte/tests/parser-legacy/samples/convert-entities-line-feed/output.json
 create mode 100644 packages/svelte/tests/runtime-runes/samples/html-entity-line-feed/Component.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/html-entity-line-feed/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/html-entity-line-feed/main.svelte

diff --git a/.changeset/tricky-donkeys-clap.md b/.changeset/tricky-donkeys-clap.md
new file mode 100644
index 0000000000..b363b4ff57
--- /dev/null
+++ b/.changeset/tricky-donkeys-clap.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: preserve line feed character references in attribute values
diff --git a/packages/svelte/src/compiler/phases/1-parse/utils/html.js b/packages/svelte/src/compiler/phases/1-parse/utils/html.js
index 1d660298c7..ccb2005054 100644
--- a/packages/svelte/src/compiler/phases/1-parse/utils/html.js
+++ b/packages/svelte/src/compiler/phases/1-parse/utils/html.js
@@ -60,7 +60,7 @@ export function decode_character_references(html, is_attribute_value) {
 				return match;
 			}
 
-			return String.fromCodePoint(validate_code(code));
+			return String.fromCodePoint(validate_code(code, is_attribute_value));
 		}
 	);
 }
@@ -75,10 +75,15 @@ const NUL = 0;
 // Also see: https://en.wikipedia.org/wiki/Plane_(Unicode)
 // Also see: https://html.spec.whatwg.org/multipage/parsing.html#preprocessing-the-input-stream
 
-/** @param {number} code */
-function validate_code(code) {
-	// line feed becomes generic whitespace
-	if (code === 10) {
+/**
+ * @param {number} code
+ * @param {boolean} is_attribute_value
+ */
+function validate_code(code, is_attribute_value) {
+	// line feed becomes generic whitespace, since it is collapsed along with the
+	// surrounding whitespace anyway. In an attribute value it is significant, so it
+	// is left alone there
+	if (code === 10 && !is_attribute_value) {
 		return 32;
 	}
 
diff --git a/packages/svelte/tests/parser-legacy/samples/convert-entities-line-feed/input.svelte b/packages/svelte/tests/parser-legacy/samples/convert-entities-line-feed/input.svelte
new file mode 100644
index 0000000000..3ce2c605d6
--- /dev/null
+++ b/packages/svelte/tests/parser-legacy/samples/convert-entities-line-feed/input.svelte
@@ -0,0 +1 @@
+<p title="A&#x0A;B">A&#x0A;B</p>
diff --git a/packages/svelte/tests/parser-legacy/samples/convert-entities-line-feed/output.json b/packages/svelte/tests/parser-legacy/samples/convert-entities-line-feed/output.json
new file mode 100644
index 0000000000..5d1127ccdc
--- /dev/null
+++ b/packages/svelte/tests/parser-legacy/samples/convert-entities-line-feed/output.json
@@ -0,0 +1,53 @@
+{
+	"html": {
+		"type": "Fragment",
+		"start": 0,
+		"end": 32,
+		"children": [
+			{
+				"type": "Element",
+				"start": 0,
+				"end": 32,
+				"name": "p",
+				"attributes": [
+					{
+						"type": "Attribute",
+						"start": 3,
+						"end": 19,
+						"name": "title",
+						"name_loc": {
+							"start": {
+								"line": 1,
+								"column": 3,
+								"character": 3
+							},
+							"end": {
+								"line": 1,
+								"column": 8,
+								"character": 8
+							}
+						},
+						"value": [
+							{
+								"start": 10,
+								"end": 18,
+								"type": "Text",
+								"raw": "A&#x0A;B",
+								"data": "A\nB"
+							}
+						]
+					}
+				],
+				"children": [
+					{
+						"type": "Text",
+						"start": 20,
+						"end": 28,
+						"raw": "A&#x0A;B",
+						"data": "A B"
+					}
+				]
+			}
+		]
+	}
+}
diff --git a/packages/svelte/tests/runtime-runes/samples/html-entity-line-feed/Component.svelte b/packages/svelte/tests/runtime-runes/samples/html-entity-line-feed/Component.svelte
new file mode 100644
index 0000000000..85b608c739
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/html-entity-line-feed/Component.svelte
@@ -0,0 +1,5 @@
+<script>
+	const { text } = $props();
+</script>
+
+<span id="prop">{text}</span>
diff --git a/packages/svelte/tests/runtime-runes/samples/html-entity-line-feed/_config.js b/packages/svelte/tests/runtime-runes/samples/html-entity-line-feed/_config.js
new file mode 100644
index 0000000000..f6befd7703
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/html-entity-line-feed/_config.js
@@ -0,0 +1,15 @@
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		// a line feed entity in an attribute value stays a line feed...
+		assert.equal(target.querySelector('#attr')?.getAttribute('title'), 'A\nB');
+		assert.equal(target.querySelector('#attr-decimal')?.getAttribute('title'), 'A\nB');
+
+		// ...including when the attribute is a prop passed to a component
+		assert.equal(target.querySelector('#prop')?.textContent, 'A\nB');
+
+		// other entities in attribute values still decode
+		assert.equal(target.querySelector('#attr-other-entity')?.getAttribute('title'), '©');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/html-entity-line-feed/main.svelte b/packages/svelte/tests/runtime-runes/samples/html-entity-line-feed/main.svelte
new file mode 100644
index 0000000000..d7f5684351
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/html-entity-line-feed/main.svelte
@@ -0,0 +1,9 @@
+<script>
+	import Component from './Component.svelte';
+</script>
+
+<span id="attr" title="A&#x0A;B"></span>
+<span id="attr-decimal" title="A&#10;B"></span>
+<span id="attr-other-entity" title="&copy;"></span>
+
+<Component text="A&#x0A;B" />

From c575b07bca37178cd8ce8c10389ece6dd33e8c96 Mon Sep 17 00:00:00 2001
From: Ion <ivanterescheenko@gmail.com>
Date: Tue, 25 Aug 2026 16:15:19 +0200
Subject: [PATCH 192/222] feat: support `defaultValue` on `<select>` (#18591)

Closes #18447

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/tall-hounds-tap.md                 |  5 +
 .../docs/03-template-syntax/12-bind.md        | 13 +++
 packages/svelte/elements.d.ts                 |  3 +
 .../client/visitors/RegularElement.js         | 26 +++++
 .../client/visitors/shared/element.js         |  7 +-
 .../server/visitors/RegularElement.js         |  2 +-
 .../server/visitors/shared/element.js         |  4 +-
 .../client/dom/elements/attributes.js         | 50 +++++-----
 .../client/dom/elements/bindings/select.js    | 56 ++++++++++-
 packages/svelte/src/internal/client/index.js  |  9 +-
 .../svelte/src/internal/server/renderer.js    | 21 ++--
 .../form-default-value-select/_config.js      | 96 +++++++++++++++++++
 .../form-default-value-select/main.svelte     | 79 +++++++++++++++
 .../select-default-value/_expected.html       | 25 +++++
 .../samples/select-default-value/main.svelte  | 34 +++++++
 15 files changed, 393 insertions(+), 37 deletions(-)
 create mode 100644 .changeset/tall-hounds-tap.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/form-default-value-select/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/form-default-value-select/main.svelte
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/select-default-value/_expected.html
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/select-default-value/main.svelte

diff --git a/.changeset/tall-hounds-tap.md b/.changeset/tall-hounds-tap.md
new file mode 100644
index 0000000000..3a9f7d79cb
--- /dev/null
+++ b/.changeset/tall-hounds-tap.md
@@ -0,0 +1,5 @@
+---
+'svelte': minor
+---
+
+feat: support `defaultValue` on `<select>`
diff --git a/documentation/docs/03-template-syntax/12-bind.md b/documentation/docs/03-template-syntax/12-bind.md
index b93f207e71..ee91d607f0 100644
--- a/documentation/docs/03-template-syntax/12-bind.md
+++ b/documentation/docs/03-template-syntax/12-bind.md
@@ -251,6 +251,19 @@ You can give the `<select>` a default value by adding a `selected` attribute to
 </select>
 ```
 
+Since 5.57.0, if a `<select>` has a `defaultValue` and is part of a form, it will revert to that value instead of the empty string when the form is reset. Note that for the initial render the value of the binding takes precedence unless it is `null` or `undefined`.
+
+```svelte
+<form>
+	<select bind:value defaultValue="b">
+		<option>a</option>
+		<option>b</option>
+		<option>c</option>
+	</select>
+	<input type="reset" value="Reset">
+</form>
+```
+
 ## `<audio>`
 
 `<audio>` elements have their own set of bindings — five two-way ones...
diff --git a/packages/svelte/elements.d.ts b/packages/svelte/elements.d.ts
index daa40635b6..15837f831a 100644
--- a/packages/svelte/elements.d.ts
+++ b/packages/svelte/elements.d.ts
@@ -1352,6 +1352,9 @@ export interface HTMLSelectAttributes extends HTMLAttributes<HTMLSelectElement>
 	required?: boolean | undefined | null;
 	size?: number | undefined | null;
 	value?: any;
+	// needs both casing variants because language tools does lowercase names of non-shorthand attributes
+	defaultValue?: any;
+	defaultvalue?: any;
 
 	'on:change'?: ChangeEventHandler<HTMLSelectElement> | undefined | null;
 	onchange?: ChangeEventHandler<HTMLSelectElement> | undefined | null;
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
index 4c1538c331..401891b41b 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
@@ -229,6 +229,12 @@ export function RegularElement(node, context) {
 				continue;
 			}
 
+			// `<select defaultValue>` needs the options to exist before it can mark one
+			// as selected, so it is handled after the children, alongside `value`
+			if (node.name === 'select' && get_attribute_name(node, attribute) === 'defaultValue') {
+				continue;
+			}
+
 			const name = get_attribute_name(node, attribute);
 
 			if (
@@ -511,6 +517,26 @@ export function RegularElement(node, context) {
 		}
 	}
 
+	// deferred from the attribute loop above, so that the options it selects from
+	// have been created and had their values assigned
+	if (!has_spread && name === 'select') {
+		for (const attribute of /** @type {AST.Attribute[]} */ (attributes)) {
+			if (get_attribute_name(node, attribute) === 'defaultValue') {
+				const { value, has_state } = build_attribute_value(attribute.value, context, (v, m) =>
+					context.state.memoizer.add(v, m)
+				);
+
+				const update = b.stmt(b.call('$.set_default_select_value', node_id, value));
+
+				(has_state ? context.state.update : context.state.init).push(update);
+				if (!bindings.has('value')) {
+					context.state.init.push(b.stmt(b.call('$.init_select', node_id)));
+				}
+				break;
+			}
+		}
+	}
+
 	context.state.template.pop_element();
 }
 
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/element.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/element.js
index 58ed88855f..ec0ca83cb4 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/element.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/element.js
@@ -30,6 +30,7 @@ export function build_attribute_effect(
 ) {
 	/** @type {ObjectExpression['properties']} */
 	const values = [];
+	const is_select = element.type === 'RegularElement' && element.name === 'select';
 
 	const memoizer = new Memoizer();
 
@@ -48,7 +49,11 @@ export function build_attribute_effect(
 				context.state.init.push(b.var(id, value));
 				values.push(b.init(attribute.name, b.id(id)));
 			} else {
-				values.push(b.init(attribute.name, value));
+				const name =
+					is_select && normalize_attribute(attribute.name) === 'defaultValue'
+						? 'defaultValue'
+						: attribute.name;
+				values.push(b.init(name, value));
 			}
 		} else {
 			let value = /** @type {Expression} */ (context.visit(attribute));
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/RegularElement.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/RegularElement.js
index 90c34d7035..f31de46378 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/RegularElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/RegularElement.js
@@ -46,7 +46,7 @@ export function RegularElement(node, context) {
 		node.attributes.some(
 			(attribute) =>
 				((attribute.type === 'Attribute' || attribute.type === 'BindDirective') &&
-					attribute.name === 'value') ||
+					(attribute.name === 'value' || attribute.name.toLowerCase() === 'defaultvalue')) ||
 				attribute.type === 'SpreadAttribute'
 		);
 	const is_option_special = name === 'option';
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js
index 6440510b01..5081d12c80 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js
@@ -306,12 +306,14 @@ function get_attribute_name(element, attribute) {
  * @param {(expression: Expression, metadata: ExpressionMetadata) => Expression} transform
  */
 export function build_spread_object(element, attributes, context, transform) {
+	const is_select = element.type === 'RegularElement' && element.name === 'select';
 	const object = b.object(
 		attributes.map((attribute) => {
 			if (attribute.type === 'transformed') {
 				return b.prop('init', b.key(attribute.name), attribute.expression);
 			} else if (attribute.type === 'Attribute') {
-				const name = get_attribute_name(element, attribute);
+				let name = get_attribute_name(element, attribute);
+				if (is_select && name === 'defaultvalue') name = 'defaultValue';
 				const value = build_attribute_value(
 					attribute.value,
 					context,
diff --git a/packages/svelte/src/internal/client/dom/elements/attributes.js b/packages/svelte/src/internal/client/dom/elements/attributes.js
index 69d4dd42a8..7439db56e9 100644
--- a/packages/svelte/src/internal/client/dom/elements/attributes.js
+++ b/packages/svelte/src/internal/client/dom/elements/attributes.js
@@ -26,7 +26,12 @@ import { set_class } from './class.js';
 import { set_style } from './style.js';
 import { ATTACHMENT_KEY, NAMESPACE_HTML, UNINITIALIZED } from '../../../../constants.js';
 import { branch, destroy_effect, effect, managed } from '../../reactivity/effects.js';
-import { init_select, select_option } from './bindings/select.js';
+import {
+	init_select,
+	select_option,
+	set_default_select_value,
+	set_selected
+} from './bindings/select.js';
 import { flatten } from '../../reactivity/async.js';
 
 export const CLASS = Symbol('class');
@@ -122,25 +127,6 @@ export function set_checked(element, checked) {
 	element.checked = checked;
 }
 
-/**
- * Sets the `selected` attribute on an `option` element.
- * Not set through the property because that doesn't reflect to the DOM,
- * which means it wouldn't be taken into account when a form is reset.
- * @param {HTMLOptionElement} element
- * @param {boolean} selected
- */
-export function set_selected(element, selected) {
-	if (selected) {
-		// The selected option could've changed via user selection, and
-		// setting the value without this check would set it back.
-		if (!element.hasAttribute('selected')) {
-			element.setAttribute('selected', '');
-		}
-	} else {
-		element.removeAttribute('selected');
-	}
-}
-
 /**
  * Applies the default checked property without influencing the current checked property.
  * @param {HTMLInputElement} element
@@ -310,6 +296,7 @@ function set_attributes(
 
 	var current = prev || {};
 	var is_option_element = element.nodeName === OPTION_TAG;
+	var is_select_element = element.nodeName === SELECT_TAG;
 
 	for (var key in prev) {
 		// don't null our internal $$onX listeners
@@ -446,6 +433,9 @@ function set_attributes(
 
 			var is_default = name === 'defaultValue' || name === 'defaultChecked';
 
+			// A select's default value is represented by selected options, not a property.
+			if (is_select_element && name === 'defaultValue') continue;
+
 			if (value == null && !is_custom_element && !is_default) {
 				attributes[key] = null;
 
@@ -531,8 +521,16 @@ export function attribute_effect(
 				skip_warning
 			);
 
-			if (inited && is_select && 'value' in next) {
-				select_option(/** @type {HTMLSelectElement} */ (element), next.value);
+			if (inited && is_select) {
+				var select = /** @type {HTMLSelectElement} */ (element);
+
+				if ('defaultValue' in next) {
+					set_default_select_value(select, next.defaultValue, false);
+				}
+
+				if ('value' in next) {
+					select_option(select, next.value);
+				}
 			}
 
 			for (let symbol of Object.getOwnPropertySymbols(effects)) {
@@ -557,7 +555,13 @@ export function attribute_effect(
 			var select = /** @type {HTMLSelectElement} */ (element);
 
 			effect(() => {
-				select_option(select, /** @type {Record<string | symbol, any>} */ (prev).value, true);
+				var attrs = /** @type {Record<string | symbol, any>} */ (prev);
+
+				if ('defaultValue' in attrs) {
+					set_default_select_value(select, attrs.defaultValue, true);
+				}
+
+				select_option(select, attrs.value, true);
 				init_select(select);
 			});
 		}
diff --git a/packages/svelte/src/internal/client/dom/elements/bindings/select.js b/packages/svelte/src/internal/client/dom/elements/bindings/select.js
index a408613104..fd1ebb92b8 100644
--- a/packages/svelte/src/internal/client/dom/elements/bindings/select.js
+++ b/packages/svelte/src/internal/client/dom/elements/bindings/select.js
@@ -6,6 +6,50 @@ import * as w from '../../../warnings.js';
 import { Batch, current_batch, previous_batch } from '../../../reactivity/batch.js';
 import { async_mode_flag } from '../../../../flags/index.js';
 
+/**
+ * Sets the `selected` attribute on an option so form reset can restore it.
+ * @param {HTMLOptionElement} option
+ * @param {boolean} selected
+ */
+export function set_selected(option, selected) {
+	if (selected) {
+		if (!option.hasAttribute('selected')) option.setAttribute('selected', '');
+	} else {
+		option.removeAttribute('selected');
+	}
+}
+
+/**
+ * Sets the options a form reset should restore without changing the current selection.
+ * The initial call is allowed to establish the current selection when no value exists.
+ * @param {HTMLSelectElement} select
+ * @param {any} value
+ * @param {boolean} [mounting]
+ */
+export function set_default_select_value(select, value, mounting = !('__defaultValue' in select)) {
+	// The DOM cannot recover unmatched, object or multiple defaults from selected options.
+	// Keep the requested value so option mutations can reapply it; property presence also
+	// distinguishes the initial application from later updates when the value is undefined.
+	// @ts-expect-error
+	select.__defaultValue = value;
+	var values = select.multiple ? (value == null ? [] : value) : null;
+
+	if (select.multiple && !is_array(values)) return;
+	var selected = !mounting || '__value' in select ? new Set(select.selectedOptions) : null;
+
+	for (var option of select.options) {
+		var option_value = get_option_value(option);
+		var is_selected = select.multiple
+			? /** @type {any[]} */ (values).includes(option_value)
+			: is(option_value, value);
+		set_selected(option, is_selected);
+	}
+
+	if (selected !== null) {
+		for (option of select.options) option.selected = selected.has(option);
+	}
+}
+
 /**
  * Selects the correct option(s) (depending on whether this is a multiple select)
  * @template V
@@ -60,9 +104,15 @@ export function init_select(select) {
 		// Reacting to them could revert a user-initiated selection change, because the
 		// records are delivered as soon as any listener returns (e.g. a delegated `input`
 		// handler), which can happen before the `change` handler has updated `__value`
-		if (entries.every(is_selectedcontent_mutation) || !('__value' in select)) return;
-		// @ts-ignore
-		select_option(select, select.__value);
+		if (entries.every(is_selectedcontent_mutation)) return;
+
+		if ('__defaultValue' in select) {
+			set_default_select_value(select, select.__defaultValue, false);
+		}
+
+		if ('__value' in select) {
+			select_option(select, select.__value);
+		}
 		// Deliberately don't update the potential binding value,
 		// the model should be preserved unless explicitly changed
 	});
diff --git a/packages/svelte/src/internal/client/index.js b/packages/svelte/src/internal/client/index.js
index 8c922b0b84..15e92aa255 100644
--- a/packages/svelte/src/internal/client/index.js
+++ b/packages/svelte/src/internal/client/index.js
@@ -33,7 +33,6 @@ export {
 	set_xlink_attribute,
 	set_value,
 	set_checked,
-	set_selected,
 	set_default_checked,
 	set_default_value,
 	CLASS,
@@ -62,7 +61,13 @@ export {
 } from './dom/elements/bindings/media.js';
 export { bind_online } from './dom/elements/bindings/navigator.js';
 export { bind_prop } from './dom/elements/bindings/props.js';
-export { bind_select_value, init_select, select_option } from './dom/elements/bindings/select.js';
+export {
+	bind_select_value,
+	init_select,
+	select_option,
+	set_selected,
+	set_default_select_value
+} from './dom/elements/bindings/select.js';
 export { bind_element_size, bind_resize_observer } from './dom/elements/bindings/size.js';
 export { bind_this } from './dom/elements/bindings/this.js';
 export {
diff --git a/packages/svelte/src/internal/server/renderer.js b/packages/svelte/src/internal/server/renderer.js
index 1a5199d18e..240a7aa686 100644
--- a/packages/svelte/src/internal/server/renderer.js
+++ b/packages/svelte/src/internal/server/renderer.js
@@ -13,7 +13,7 @@ import { attributes } from './index.js';
 import { get_render_context, with_render_context, init_render_context } from './render-context.js';
 import { sha256 } from './crypto.js';
 import * as devalue from 'devalue';
-import { has_own_property, noop } from '../shared/utils.js';
+import { has_own_property, is_array, noop } from '../shared/utils.js';
 import { escape_html } from '../../escaping.js';
 
 /** @typedef {'head' | 'body'} RendererType */
@@ -89,7 +89,7 @@ export class Renderer {
 	 * State that is local to the branch it is declared in.
 	 * It will be shallow-copied to all children.
 	 *
-	 * @type {{ select_value: string | undefined }}
+	 * @type {{ select_value: any, select_default_multiple: boolean }}
 	 */
 	local;
 
@@ -101,7 +101,9 @@ export class Renderer {
 		this.#parent = parent;
 
 		this.global = global;
-		this.local = parent ? { ...parent.local } : { select_value: undefined };
+		this.local = parent
+			? { ...parent.local }
+			: { select_value: undefined, select_default_multiple: false };
 		this.type = parent ? parent.type : 'body';
 	}
 
@@ -338,11 +340,14 @@ export class Renderer {
 	 * @returns {void}
 	 */
 	select(attrs, fn, css_hash, classes, styles, flags, is_rich) {
-		const { value, ...select_attrs } = attrs;
+		const { value, defaultValue, ...select_attrs } = attrs;
+		if (select_attrs.multiple === '') select_attrs.multiple = true;
 
 		this.push(`<select${attributes(select_attrs, css_hash, classes, styles, flags)}>`);
 		this.child((renderer) => {
-			renderer.local.select_value = value;
+			renderer.local.select_value = value === undefined ? defaultValue : value;
+			renderer.local.select_default_multiple =
+				value === undefined && Boolean(select_attrs.multiple);
 			fn(renderer);
 		});
 		this.push(`${is_rich ? '<!>' : ''}</select>`);
@@ -370,7 +375,11 @@ export class Renderer {
 				value = attrs.value;
 			}
 
-			if (value === this.local.select_value) {
+			if (
+				this.local.select_default_multiple
+					? is_array(this.local.select_value) && this.local.select_value.includes(value)
+					: value === this.local.select_value
+			) {
 				renderer.#out.push(' selected=""');
 			}
 
diff --git a/packages/svelte/tests/runtime-runes/samples/form-default-value-select/_config.js b/packages/svelte/tests/runtime-runes/samples/form-default-value-select/_config.js
new file mode 100644
index 0000000000..5d0c964969
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/form-default-value-select/_config.js
@@ -0,0 +1,96 @@
+import { test } from '../../test';
+import { flushSync } from 'svelte';
+
+export default test({
+	async test({ assert, target }) {
+		/** @param {HTMLSelectElement} select @param {boolean[]} expected */
+		function check(select, expected) {
+			assert.deepEqual(
+				[...select.options].map((option) => option.selected),
+				expected
+			);
+		}
+
+		/** @param {HTMLSelectElement} select @param {number[]} indexes */
+		function select(select, indexes) {
+			for (let i = 0; i < select.options.length; i++) {
+				select.options[i].selected = indexes.includes(i);
+			}
+			select.dispatchEvent(new Event('change', { bubbles: true }));
+		}
+
+		const selects = target.querySelectorAll('select');
+		const reset = /** @type {HTMLInputElement} */ (target.querySelector('input[type=reset]'));
+		/** @param {string} name */
+		const button = (name) => /** @type {HTMLButtonElement} */ (target.querySelector(`.${name}`));
+
+		check(selects[0], [false, true, false]);
+		check(selects[1], [false, false, true]);
+		check(selects[2], [false, true, false]);
+		check(selects[3], [true]);
+		check(selects[4], [false, true]);
+		check(selects[5], [false, true, false]);
+		check(selects[6], [true, false]);
+		check(selects[7], [true, false, true]);
+		check(selects[8], [false, false, true]);
+
+		select(selects[0], [2]);
+		select(selects[1], [0]);
+		select(selects[5], [2]);
+		select(selects[7], [1]);
+		flushSync();
+
+		reset.click();
+		await Promise.resolve();
+		flushSync();
+		check(selects[0], [false, true, false]);
+		check(selects[1], [false, true, false]);
+		check(selects[5], [false, true, false]);
+		check(selects[7], [true, false, true]);
+
+		select(selects[2], [2]);
+		select(selects[5], [2]);
+		button('update').click();
+		flushSync();
+		check(selects[2], [false, false, true]);
+		check(selects[5], [false, false, true]);
+		assert.deepEqual(
+			[...selects[5].options].map((option) => option.defaultSelected),
+			[true, false, false]
+		);
+
+		button('add').click();
+		flushSync();
+		await Promise.resolve();
+		check(selects[3], [true, false]);
+		assert.equal(selects[3].options[1].defaultSelected, true);
+
+		reset.click();
+		await Promise.resolve();
+		flushSync();
+		check(selects[0], [true, false, false]);
+		check(selects[2], [true, false, false]);
+		check(selects[3], [false, true]);
+		check(selects[5], [true, false, false]);
+
+		select(selects[5], [2]);
+		select(selects[7], [1]);
+		button('remove').click();
+		button('clear').click();
+		flushSync();
+		assert.equal(
+			[...selects[5].options].some((option) => option.defaultSelected),
+			false
+		);
+		assert.equal(
+			[...selects[7].options].some((option) => option.defaultSelected),
+			false
+		);
+
+		reset.click();
+		await Promise.resolve();
+		flushSync();
+		check(selects[5], [true, false, false]);
+		check(selects[7], [false, false, false]);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/form-default-value-select/main.svelte b/packages/svelte/tests/runtime-runes/samples/form-default-value-select/main.svelte
new file mode 100644
index 0000000000..daa1f9ceee
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/form-default-value-select/main.svelte
@@ -0,0 +1,79 @@
+<script>
+	let selected1 = $state();
+	let selected2 = $state('c');
+	let selected3 = $state();
+	let selected4 = $state(['c']);
+	let defaultValue = $state('b');
+	let multipleDefault = $state(/** @type {string[] | undefined} */ (['a', 'c']));
+	let options = $state(['a']);
+	let props = $state({ defaultValue: 'b' });
+</script>
+
+<form>
+	<select {defaultValue} bind:value={selected1}>
+		<option value="a">A</option>
+		<option value="b">B</option>
+		<option value="c">C</option>
+	</select>
+
+	<select {defaultValue} bind:value={selected2}>
+		<option value="a">A</option>
+		<option value="b">B</option>
+		<option value="c">C</option>
+	</select>
+
+	<select {defaultValue}>
+		<option value="a">A</option>
+		<option value="b">B</option>
+		<option value="c">C</option>
+	</select>
+
+	<select defaultValue="b">
+		{#each options as option}
+			<option value={option}>{option}</option>
+		{/each}
+	</select>
+
+	<select defaultvalue="b">
+		<option value="a">A</option>
+		<option value="b">B</option>
+	</select>
+
+	<select {...props} bind:value={selected3}>
+		<option value="a">A</option>
+		<option value="b">B</option>
+		<option value="c">C</option>
+	</select>
+
+	<select {...{ defaultValue: 'b' }} defaultValue="a">
+		<option value="a">A</option>
+		<option value="b">B</option>
+	</select>
+
+	<select multiple defaultValue={multipleDefault}>
+		<option value="a">A</option>
+		<option value="b">B</option>
+		<option value="c">C</option>
+	</select>
+
+	<select multiple defaultValue={multipleDefault} bind:value={selected4}>
+		<option value="a">A</option>
+		<option value="b">B</option>
+		<option value="c">C</option>
+	</select>
+
+	<input type="reset" value="Reset" />
+	<button
+		type="button"
+		class="update"
+		onclick={() => {
+			defaultValue = 'a';
+			props.defaultValue = 'a';
+		}}>Update defaults</button
+	>
+	<button type="button" class="add" onclick={() => options.push('b')}>Add option</button>
+	<button type="button" class="remove" onclick={() => delete props.defaultValue}>Remove default</button>
+	<button type="button" class="clear" onclick={() => (multipleDefault = undefined)}>Clear defaults</button>
+</form>
+
+<p>{selected1} {selected2} {selected3} {selected4.join(',')}</p>
diff --git a/packages/svelte/tests/server-side-rendering/samples/select-default-value/_expected.html b/packages/svelte/tests/server-side-rendering/samples/select-default-value/_expected.html
new file mode 100644
index 0000000000..482f4a9d4c
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/select-default-value/_expected.html
@@ -0,0 +1,25 @@
+<select>
+	<option value="a">A</option>
+	<option selected="" value="b">B</option>
+</select>
+<select>
+	<option value="a">A</option>
+	<option selected="" value="b">B</option>
+</select>
+<select>
+	<option selected="" value="a">A</option>
+	<option value="b">B</option>
+</select>
+<select multiple="">
+	<option selected="" value="a">A</option>
+	<option value="b">B</option>
+	<option selected="" value="c">C</option>
+</select>
+<select>
+	<option value="a">A</option>
+	<option selected="" value="b">B</option>
+</select>
+<select>
+	<option selected="" value="a">A</option>
+	<option value="b">B</option>
+</select>
diff --git a/packages/svelte/tests/server-side-rendering/samples/select-default-value/main.svelte b/packages/svelte/tests/server-side-rendering/samples/select-default-value/main.svelte
new file mode 100644
index 0000000000..fe5a858dd0
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/select-default-value/main.svelte
@@ -0,0 +1,34 @@
+<script>
+	const props = { defaultValue: 'b' };
+</script>
+
+<select defaultValue="b">
+	<option value="a">A</option>
+	<option value="b">B</option>
+</select>
+
+<select {...props}>
+	<option value="a">A</option>
+	<option value="b">B</option>
+</select>
+
+<select defaultValue="b" value="a">
+	<option value="a">A</option>
+	<option value="b">B</option>
+</select>
+
+<select multiple="" defaultValue={['a', 'c']}>
+	<option value="a">A</option>
+	<option value="b">B</option>
+	<option value="c">C</option>
+</select>
+
+<select defaultvalue="b">
+	<option value="a">A</option>
+	<option value="b">B</option>
+</select>
+
+<select {...{ defaultValue: 'b' }} defaultValue="a">
+	<option value="a">A</option>
+	<option value="b">B</option>
+</select>

From 14ec75c5fe88e4f54ab588fa8e7ca92493cd1116 Mon Sep 17 00:00:00 2001
From: Mathias Picker <48158184+MathiasWP@users.noreply.github.com>
Date: Tue, 25 Aug 2026 16:16:17 +0200
Subject: [PATCH 193/222] perf: fold SSR block-open markers into the branch's
 first push (#18712)

One fewer `$$renderer.push` per rendered branch
---
 .changeset/gold-moons-shave.md                |  5 ++
 .../3-transform/server/visitors/EachBlock.js  | 10 +++-
 .../3-transform/server/visitors/IfBlock.js    |  8 +--
 .../server/visitors/shared/utils.js           | 30 +++++++++++
 .../_expected/server/index.svelte.js          |  3 +-
 .../_expected/server/index.svelte.js          | 54 +++++++------------
 .../_expected/server/index.svelte.js          |  9 ++--
 .../_expected/server/index.svelte.js          |  3 +-
 8 files changed, 70 insertions(+), 52 deletions(-)
 create mode 100644 .changeset/gold-moons-shave.md

diff --git a/.changeset/gold-moons-shave.md b/.changeset/gold-moons-shave.md
new file mode 100644
index 0000000000..9ee98321b7
--- /dev/null
+++ b/.changeset/gold-moons-shave.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+perf: fold SSR block-open markers into the branch's first push
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/EachBlock.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/EachBlock.js
index cb5a61d52f..923c4dd394 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/EachBlock.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/EachBlock.js
@@ -2,7 +2,13 @@
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types.js' */
 import * as b from '#compiler/builders';
-import { block_close, block_open, block_open_else, create_child_block } from './shared/utils.js';
+import {
+	block_close,
+	block_open,
+	block_open_else,
+	create_child_block,
+	prepend_block_marker
+} from './shared/utils.js';
 
 /**
  * @param {AST.EachBlock} node
@@ -51,7 +57,7 @@ export function EachBlock(node, context) {
 
 		const fallback = /** @type {BlockStatement} */ (context.visit(node.fallback));
 
-		fallback.body.unshift(b.stmt(b.call(b.id('$$renderer.push'), block_open_else)));
+		prepend_block_marker(fallback, /** @type {string} */ (block_open_else.value));
 
 		statements.push(
 			b.if(
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/IfBlock.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/IfBlock.js
index 2d1a22605c..ea636e2064 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/IfBlock.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/IfBlock.js
@@ -2,7 +2,7 @@
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types.js' */
 import * as b from '#compiler/builders';
-import { block_close, create_child_block } from './shared/utils.js';
+import { block_close, create_child_block, prepend_block_marker } from './shared/utils.js';
 
 /**
  * @param {AST.IfBlock} node
@@ -10,7 +10,7 @@ import { block_close, create_child_block } from './shared/utils.js';
  */
 export function IfBlock(node, context) {
 	const consequent = /** @type {BlockStatement} */ (context.visit(node.consequent));
-	consequent.body.unshift(b.stmt(b.call(b.id('$$renderer.push'), b.literal(`<!--[0-->`))));
+	prepend_block_marker(consequent, `<!--[0-->`);
 
 	/** @type {IfStatement} */
 	let if_statement = b.if(/** @type {Expression} */ (context.visit(node.test)), consequent);
@@ -22,7 +22,7 @@ export function IfBlock(node, context) {
 	// Walk the else-if chain, flattening branches
 	for (const elseif of node.metadata.flattened ?? []) {
 		const branch = /** @type {BlockStatement} */ (context.visit(elseif.consequent));
-		branch.body.unshift(b.stmt(b.call(b.id('$$renderer.push'), b.literal(`<!--[${index++}-->`))));
+		prepend_block_marker(branch, `<!--[${index++}-->`);
 
 		current_if = current_if.alternate = b.if(
 			/** @type {Expression} */ (context.visit(elseif.test)),
@@ -34,7 +34,7 @@ export function IfBlock(node, context) {
 	// Handle final else (or remaining async chain)
 	const final_alternate = alt ? /** @type {BlockStatement} */ (context.visit(alt)) : b.block([]);
 
-	final_alternate.body.unshift(b.stmt(b.call(b.id('$$renderer.push'), b.literal(`<!--[-1-->`))));
+	prepend_block_marker(final_alternate, `<!--[-1-->`);
 	current_if.alternate = final_alternate;
 
 	context.state.template.push(
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
index 28d2d762f9..f38ae6164c 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
@@ -180,6 +180,36 @@ export function build_template(template) {
 	return statements;
 }
 
+/**
+ * Prepends a hydration marker (e.g. `<!--[0-->`) to a branch. The branch has already been
+ * turned into statements by `build_template`, so if it happens to start with a static
+ * `$$renderer.push(...)` we fold the marker into that call rather than emitting a second one.
+ * @param {BlockStatement} block
+ * @param {string} marker
+ */
+export function prepend_block_marker(block, marker) {
+	const first = block.body[0];
+
+	if (
+		first?.type === 'ExpressionStatement' &&
+		first.expression.type === 'CallExpression' &&
+		first.expression.callee.type === 'Identifier' &&
+		first.expression.callee.name === '$$renderer.push' &&
+		first.expression.arguments.length === 1 &&
+		first.expression.arguments[0].type === 'TemplateLiteral'
+	) {
+		const quasi = first.expression.arguments[0].quasis[0];
+
+		// markers never contain characters that need escaping in a template literal
+		quasi.value.cooked = marker + quasi.value.cooked;
+		quasi.value.raw = marker + quasi.value.raw;
+
+		return;
+	}
+
+	block.body.unshift(b.stmt(b.call(b.id('$$renderer.push'), b.literal(marker))));
+}
+
 /**
  *
  * @param {AST.Attribute['value']} value
diff --git a/packages/svelte/tests/snapshot/samples/async-each-fallback-hoisting/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-each-fallback-hoisting/_expected/server/index.svelte.js
index b331875d04..71ccba4d59 100644
--- a/packages/svelte/tests/snapshot/samples/async-each-fallback-hoisting/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-each-fallback-hoisting/_expected/server/index.svelte.js
@@ -15,8 +15,7 @@ export default function Async_each_fallback_hoisting($$renderer) {
 				$$renderer.push(async () => $.escape(await Promise.reject('This should never be reached')));
 			}
 		} else {
-			$$renderer.push('<!--[!-->');
-			$$renderer.push(`<!---->`);
+			$$renderer.push(`<!--[!--><!---->`);
 			$$renderer.push(async () => $.escape(await Promise.resolve(4)));
 		}
 	});
diff --git a/packages/svelte/tests/snapshot/samples/async-if-chain/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-if-chain/_expected/server/index.svelte.js
index 3fc25288ad..466683b868 100644
--- a/packages/svelte/tests/snapshot/samples/async-if-chain/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-if-chain/_expected/server/index.svelte.js
@@ -12,14 +12,11 @@ export default function Async_if_chain($$renderer) {
 
 	$$renderer.async_block([$$promises[0]], ($$renderer) => {
 		if (foo) {
-			$$renderer.push('<!--[0-->');
-			$$renderer.push(`foo`);
+			$$renderer.push(`<!--[0-->foo`);
 		} else if (bar) {
-			$$renderer.push('<!--[1-->');
-			$$renderer.push(`bar`);
+			$$renderer.push(`<!--[1-->bar`);
 		} else {
-			$$renderer.push('<!--[-1-->');
-			$$renderer.push(`else`);
+			$$renderer.push(`<!--[-1-->else`);
 		}
 	});
 
@@ -27,21 +24,17 @@ export default function Async_if_chain($$renderer) {
 
 	$$renderer.async_block([$$promises[0]], async ($$renderer) => {
 		if ((await $.save(foo))()) {
-			$$renderer.push('<!--[0-->');
-			$$renderer.push(`foo`);
+			$$renderer.push(`<!--[0-->foo`);
 		} else if (bar) {
-			$$renderer.push('<!--[1-->');
-			$$renderer.push(`bar`);
+			$$renderer.push(`<!--[1-->bar`);
 		} else {
 			$$renderer.push('<!--[-1-->');
 
 			$$renderer.child_block(async ($$renderer) => {
 				if ((await $.save(baz))()) {
-					$$renderer.push('<!--[0-->');
-					$$renderer.push(`baz`);
+					$$renderer.push(`<!--[0-->baz`);
 				} else {
-					$$renderer.push('<!--[-1-->');
-					$$renderer.push(`else`);
+					$$renderer.push(`<!--[-1-->else`);
 				}
 			});
 
@@ -53,21 +46,17 @@ export default function Async_if_chain($$renderer) {
 
 	$$renderer.async_block([$$promises[0]], async ($$renderer) => {
 		if ((await $.save(foo))() > 10) {
-			$$renderer.push('<!--[0-->');
-			$$renderer.push(`foo`);
+			$$renderer.push(`<!--[0-->foo`);
 		} else if (bar) {
-			$$renderer.push('<!--[1-->');
-			$$renderer.push(`bar`);
+			$$renderer.push(`<!--[1-->bar`);
 		} else {
 			$$renderer.push('<!--[-1-->');
 
 			$$renderer.async_block([$$promises[0]], async ($$renderer) => {
 				if ((await $.save(foo))() > 5) {
-					$$renderer.push('<!--[0-->');
-					$$renderer.push(`baz`);
+					$$renderer.push(`<!--[0-->baz`);
 				} else {
-					$$renderer.push('<!--[-1-->');
-					$$renderer.push(`else`);
+					$$renderer.push(`<!--[-1-->else`);
 				}
 			});
 
@@ -78,31 +67,24 @@ export default function Async_if_chain($$renderer) {
 	$$renderer.push(`<!--]--> `);
 
 	if (simple1) {
-		$$renderer.push('<!--[0-->');
-		$$renderer.push(`foo`);
+		$$renderer.push(`<!--[0-->foo`);
 	} else if (simple2 > 10) {
-		$$renderer.push('<!--[1-->');
-		$$renderer.push(`bar`);
+		$$renderer.push(`<!--[1-->bar`);
 	} else if (complex1() * complex2 > 100) {
-		$$renderer.push('<!--[2-->');
-		$$renderer.push(`baz`);
+		$$renderer.push(`<!--[2-->baz`);
 	} else {
-		$$renderer.push('<!--[-1-->');
-		$$renderer.push(`else`);
+		$$renderer.push(`<!--[-1-->else`);
 	}
 
 	$$renderer.push(`<!--]--> `);
 
 	$$renderer.async_block([$$promises[0]], ($$renderer) => {
 		if (blocking() > 10) {
-			$$renderer.push('<!--[0-->');
-			$$renderer.push(`foo`);
+			$$renderer.push(`<!--[0-->foo`);
 		} else if (blocking() > 5) {
-			$$renderer.push('<!--[1-->');
-			$$renderer.push(`bar`);
+			$$renderer.push(`<!--[1-->bar`);
 		} else {
-			$$renderer.push('<!--[-1-->');
-			$$renderer.push(`else`);
+			$$renderer.push(`<!--[-1-->else`);
 		}
 	});
 
diff --git a/packages/svelte/tests/snapshot/samples/dedupe-templates/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/dedupe-templates/_expected/server/index.svelte.js
index 1f4a56779e..be305165cb 100644
--- a/packages/svelte/tests/snapshot/samples/dedupe-templates/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/dedupe-templates/_expected/server/index.svelte.js
@@ -4,18 +4,15 @@ export default function Dedupe_templates($$renderer, $$props) {
 	let { a, b } = $$props;
 
 	if (a) {
-		$$renderer.push('<!--[0-->');
-		$$renderer.push(`<p class="x">hello</p>`);
+		$$renderer.push(`<!--[0--><p class="x">hello</p>`);
 	} else {
-		$$renderer.push('<!--[-1-->');
-		$$renderer.push(`<p class="x">hello</p>`);
+		$$renderer.push(`<!--[-1--><p class="x">hello</p>`);
 	}
 
 	$$renderer.push(`<!--]--> `);
 
 	if (b) {
-		$$renderer.push('<!--[0-->');
-		$$renderer.push(`<p class="x">hello</p>`);
+		$$renderer.push(`<!--[0--><p class="x">hello</p>`);
 	} else {
 		$$renderer.push('<!--[-1-->');
 	}
diff --git a/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/server/index.svelte.js
index bc346b4b0a..de22dc2f96 100644
--- a/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/server/index.svelte.js
@@ -148,8 +148,7 @@ export default function Select_with_rich_content($$renderer) {
 	$$renderer.push(`<!--]--></select> <select>`);
 
 	if (show) {
-		$$renderer.push('<!--[0-->');
-		$$renderer.push(`<!--[-->`);
+		$$renderer.push(`<!--[0--><!--[-->`);
 
 		const each_array_4 = $.ensure_array_like(items);
 

From 68e7c9b5218b613c2b58be98bc5910bfa0dbacd4 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Tue, 25 Aug 2026 16:24:46 +0200
Subject: [PATCH 194/222] fix: transform derived assignments and select
 function bindings correctly during server-side rendering (#18669)

follow-up to the fix in #18607 - there are a two more bugs related to
writeable deriveds in that area
---
 .changeset/slow-dots-smile.md                          |  5 +++++
 .../server/visitors/AssignmentExpression.js            |  2 +-
 .../3-transform/server/visitors/shared/element.js      |  5 ++---
 .../derived-forward-ref-leading-comments/_config.js    |  6 ------
 .../samples/derived-leading-comments/_config.js        |  6 ++++++
 .../main.svelte                                        | 10 ++++++++++
 .../samples/select-function-binding-derived/_config.js |  9 +++++++++
 .../select-function-binding-derived/main.svelte        |  9 +++++++++
 8 files changed, 42 insertions(+), 10 deletions(-)
 create mode 100644 .changeset/slow-dots-smile.md
 delete mode 100644 packages/svelte/tests/runtime-runes/samples/derived-forward-ref-leading-comments/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/derived-leading-comments/_config.js
 rename packages/svelte/tests/runtime-runes/samples/{derived-forward-ref-leading-comments => derived-leading-comments}/main.svelte (55%)
 create mode 100644 packages/svelte/tests/runtime-runes/samples/select-function-binding-derived/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/select-function-binding-derived/main.svelte

diff --git a/.changeset/slow-dots-smile.md b/.changeset/slow-dots-smile.md
new file mode 100644
index 0000000000..18d2517b6c
--- /dev/null
+++ b/.changeset/slow-dots-smile.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: transform derived assignments and select function bindings correctly during server-side rendering
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/AssignmentExpression.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/AssignmentExpression.js
index e6a1a86aa8..d555b6bb1d 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/AssignmentExpression.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/AssignmentExpression.js
@@ -110,7 +110,7 @@ function build_assignment(operator, left, right, context) {
 			context.visit(build_assignment_value(operator, left, right))
 		);
 
-		return b.call(binding.node, value);
+		return b.call(object, value);
 	}
 
 	return null;
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js
index 5081d12c80..b4f4facb5d 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js
@@ -324,10 +324,9 @@ export function build_spread_object(element, attributes, context, transform) {
 				return b.prop('init', b.key(name), value);
 			} else if (attribute.type === 'BindDirective') {
 				const name = get_attribute_name(element, attribute);
+				const expression = /** @type {Expression} */ (context.visit(attribute.expression));
 				const value =
-					attribute.expression.type === 'SequenceExpression'
-						? b.call(attribute.expression.expressions[0])
-						: /** @type {Expression} */ (context.visit(attribute.expression));
+					expression.type === 'SequenceExpression' ? b.call(expression.expressions[0]) : expression;
 
 				return b.prop('init', b.key(name), value);
 			}
diff --git a/packages/svelte/tests/runtime-runes/samples/derived-forward-ref-leading-comments/_config.js b/packages/svelte/tests/runtime-runes/samples/derived-forward-ref-leading-comments/_config.js
deleted file mode 100644
index 204581389d..0000000000
--- a/packages/svelte/tests/runtime-runes/samples/derived-forward-ref-leading-comments/_config.js
+++ /dev/null
@@ -1,6 +0,0 @@
-import { test } from '../../test';
-
-export default test({
-	ssrHtml: '<p>LATER</p> <input value="LATER">',
-	html: '<p>LATER</p> <input>'
-});
diff --git a/packages/svelte/tests/runtime-runes/samples/derived-leading-comments/_config.js b/packages/svelte/tests/runtime-runes/samples/derived-leading-comments/_config.js
new file mode 100644
index 0000000000..2048fbadf7
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/derived-leading-comments/_config.js
@@ -0,0 +1,6 @@
+import { test } from '../../test';
+
+export default test({
+	ssrHtml: '<p>y:y</p> <p>LATER</p> <input value="LATER">',
+	html: '<p>y:y</p> <p>LATER</p> <input>'
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/derived-forward-ref-leading-comments/main.svelte b/packages/svelte/tests/runtime-runes/samples/derived-leading-comments/main.svelte
similarity index 55%
rename from packages/svelte/tests/runtime-runes/samples/derived-forward-ref-leading-comments/main.svelte
rename to packages/svelte/tests/runtime-runes/samples/derived-leading-comments/main.svelte
index f9a1a1a6fb..0424d3fb15 100644
--- a/packages/svelte/tests/runtime-runes/samples/derived-forward-ref-leading-comments/main.svelte
+++ b/packages/svelte/tests/runtime-runes/samples/derived-leading-comments/main.svelte
@@ -1,4 +1,13 @@
 <script>
+	function write(value) {
+		return foo = value;
+	}
+
+	// a leading comment on the declaration
+	// that spans more than one line
+	let foo = $derived('x');
+	let bar = write('y');
+
 	const ctx = {
 		get later() {
 			return later;
@@ -10,5 +19,6 @@
 	let later = $derived.by(() => 'LATER');
 </script>
 
+<p>{foo}:{bar}</p>
 <p>{ctx.later}</p>
 <input bind:value={later} />
diff --git a/packages/svelte/tests/runtime-runes/samples/select-function-binding-derived/_config.js b/packages/svelte/tests/runtime-runes/samples/select-function-binding-derived/_config.js
new file mode 100644
index 0000000000..13b7302cee
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/select-function-binding-derived/_config.js
@@ -0,0 +1,9 @@
+import { test } from '../../test';
+
+export default test({
+	ssrHtml: '<select><option value="a">a</option><option value="b" selected="">b</option></select>',
+	test({ assert, target }) {
+		const select = /** @type {HTMLSelectElement} */ (target.querySelector('select'));
+		assert.equal(select.value, 'b');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/select-function-binding-derived/main.svelte b/packages/svelte/tests/runtime-runes/samples/select-function-binding-derived/main.svelte
new file mode 100644
index 0000000000..2c14566193
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/select-function-binding-derived/main.svelte
@@ -0,0 +1,9 @@
+<script>
+	let source = $state('b');
+	let value = $derived(source);
+</script>
+
+<select bind:value={() => value, (next) => (value = next)}>
+	<option value="a">a</option>
+	<option value="b">b</option>
+</select>

From c7d8233a5ce70546971413ba84282ba0518a0828 Mon Sep 17 00:00:00 2001
From: "svelte-triage-bot[bot]"
 <316883489+svelte-triage-bot[bot]@users.noreply.github.com>
Date: Tue, 25 Aug 2026 16:47:30 +0200
Subject: [PATCH 195/222] fix: apply ownership mutation ignores to bindings
 (#18718)

Fixes #18715.

Copy ignore comment info to the generated assignment so it's recognized later

---------

Co-authored-by: svelte-triage-bot <team@svelte.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/fix-binding-ownership-ignore.md    |  5 ++++
 .../client/visitors/BindDirective.js          | 23 ++++++++-----------
 .../Item.svelte                               |  6 +++++
 .../_config.js                                | 22 ++++++++++++++++++
 .../main.svelte                               |  8 +++++++
 5 files changed, 51 insertions(+), 13 deletions(-)
 create mode 100644 .changeset/fix-binding-ownership-ignore.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-binding-ignore/Item.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-binding-ignore/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-binding-ignore/main.svelte

diff --git a/.changeset/fix-binding-ownership-ignore.md b/.changeset/fix-binding-ownership-ignore.md
new file mode 100644
index 0000000000..13c9c797e3
--- /dev/null
+++ b/.changeset/fix-binding-ownership-ignore.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: apply ownership mutation ignores to binding assignments
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/BindDirective.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/BindDirective.js
index 6838e5006d..c7bf24b3f9 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/BindDirective.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/BindDirective.js
@@ -1,7 +1,7 @@
 /** @import { CallExpression, Expression, Pattern } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types' */
-import { dev, is_ignored } from '../../../../state.js';
+import { dev, ignore_map, is_ignored } from '../../../../state.js';
 import { is_text_attribute } from '../../../../utils/ast.js';
 import * as b from '#compiler/builders';
 import { binding_properties } from '../../../bindings.js';
@@ -40,9 +40,15 @@ export function BindDirective(node, context) {
 			validate_binding(context.state, node, expression);
 		}
 
-		const assignment = /** @type {Expression} */ (
-			context.visit(b.assignment('=', /** @type {Pattern} */ (node.expression), b.id('$$value')))
+		const raw_assignment = b.assignment(
+			'=',
+			/** @type {Pattern} */ (node.expression),
+			b.id('$$value')
 		);
+		// The assignment is generated, so inherit any ignores attached to the binding
+		ignore_map.set(raw_assignment, ignore_map.get(node) ?? []);
+
+		const assignment = /** @type {Expression} */ (context.visit(raw_assignment));
 
 		if (dev) {
 			// in dev, create named functions, so that `$inspect(...)` delivers
@@ -58,16 +64,7 @@ export function BindDirective(node, context) {
 			get = b.thunk(expression);
 
 			/** @type {Expression | undefined} */
-			set = b.unthunk(
-				b.arrow(
-					[b.id('$$value')],
-					/** @type {Expression} */ (
-						context.visit(
-							b.assignment('=', /** @type {Pattern} */ (node.expression), b.id('$$value'))
-						)
-					)
-				)
-			);
+			set = b.unthunk(b.arrow([b.id('$$value')], assignment));
 
 			if (get === set) {
 				set = undefined;
diff --git a/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-binding-ignore/Item.svelte b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-binding-ignore/Item.svelte
new file mode 100644
index 0000000000..7beabf6124
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-binding-ignore/Item.svelte
@@ -0,0 +1,6 @@
+<script>
+	let { item } = $props();
+</script>
+
+<!-- svelte-ignore ownership_invalid_mutation -->
+<input bind:value={item.heading} />
diff --git a/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-binding-ignore/_config.js b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-binding-ignore/_config.js
new file mode 100644
index 0000000000..11229fd13e
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-binding-ignore/_config.js
@@ -0,0 +1,22 @@
+import { flushSync } from 'svelte';
+import { ok, test } from '../../test';
+
+export default test({
+	mode: ['client'],
+	compileOptions: {
+		dev: true
+	},
+	test({ assert, target, warnings }) {
+		const input = target.querySelector('input');
+		const output = target.querySelector('p');
+		ok(input);
+		ok(output);
+
+		input.value = 'renamed';
+		input.dispatchEvent(new Event('input', { bubbles: true }));
+		flushSync();
+
+		assert.equal(output.textContent, 'renamed');
+		assert.deepEqual(warnings, []);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-binding-ignore/main.svelte b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-binding-ignore/main.svelte
new file mode 100644
index 0000000000..e5b926cb9c
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-binding-ignore/main.svelte
@@ -0,0 +1,8 @@
+<script>
+	import Item from './Item.svelte';
+
+	let item = $state({ heading: 'initial' });
+</script>
+
+<Item {item} />
+<p>{item.heading}</p>

From 955b701df2d4c44215844a07a6112462558c2a1e Mon Sep 17 00:00:00 2001
From: Khaled Waleed <foxilated@gmail.com>
Date: Tue, 25 Aug 2026 17:48:09 +0300
Subject: [PATCH 196/222] fix: measure nested transitions before applying their
 starting styles (#18647)

Fixes #18421 (regression from #16035, which re-broke the #4784
scenario).

Since #16035 the dummy delay animation runs with `fill: 'forwards'`, so
an intro's `t = 0` styles (for `slide`, `height: 0`) apply the moment
the transition is created and stay applied until the real animation
starts a frame later. Transition functions of other elements in the same
batch run after that and measure a collapsed DOM. With nested intros
(the TreeView from the issue), intro effects run deepest-first, so every
ancestor's `slide` captures a height where its children are pinned at 0.
On the issue's REPL every `<ul>` animates `0px -> 36px` (the height of a
single row) and then jumps to its real size when the animation finishes,
which is the "children pop out" behavior from #4784.

The fix waits one microtask before applying the initial styles and
creating the dummy, the same way deferred transitions (`crossfade`)
already work in `animate()`. Everything in the batch measures the DOM
first; the microtask still runs before the next paint, so elements never
render unstyled and the #14732 behavior is preserved. Verified in a real
browser that a delayed intro (`delay: 300`) stays held at `height: 0`
for the whole delay, including the first painted frame.

Most of the diff is the existing dummy/onfinish block moving into
`queue_micro_task`; hiding whitespace shows the actual change.
---
 .changeset/moody-lamps-slide.md               |   5 +
 .../client/dom/elements/transitions.js        | 149 ++++++++++--------
 .../transition-nested-measure/Nested.svelte   |  14 ++
 .../transition-nested-measure/_config.js      |  36 +++++
 .../transition-nested-measure/main.svelte     |  11 ++
 5 files changed, 147 insertions(+), 68 deletions(-)
 create mode 100644 .changeset/moody-lamps-slide.md
 create mode 100644 packages/svelte/tests/runtime-browser/samples/transition-nested-measure/Nested.svelte
 create mode 100644 packages/svelte/tests/runtime-browser/samples/transition-nested-measure/_config.js
 create mode 100644 packages/svelte/tests/runtime-browser/samples/transition-nested-measure/main.svelte

diff --git a/.changeset/moody-lamps-slide.md b/.changeset/moody-lamps-slide.md
new file mode 100644
index 0000000000..5832f12e42
--- /dev/null
+++ b/.changeset/moody-lamps-slide.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: measure nested transitions before applying their starting styles
diff --git a/packages/svelte/src/internal/client/dom/elements/transitions.js b/packages/svelte/src/internal/client/dom/elements/transitions.js
index 7c4d385807..67b177841a 100644
--- a/packages/svelte/src/internal/client/dom/elements/transitions.js
+++ b/packages/svelte/src/internal/client/dom/elements/transitions.js
@@ -337,6 +337,7 @@ export function transition(flags, element, get_fn, get_params) {
  */
 function animate(element, options, counterpart, t2, on_begin, on_finish) {
 	var is_intro = t2 === 1;
+	var aborted = false;
 
 	if (is_function(options)) {
 		// In the case of a deferred transition (such as `crossfade`), `option` will be
@@ -344,7 +345,6 @@ function animate(element, options, counterpart, t2, on_begin, on_finish) {
 		// once the DOM has been updated...
 		/** @type {Animation} */
 		var a;
-		var aborted = false;
 
 		queue_micro_task(() => {
 			if (aborted) return;
@@ -381,99 +381,112 @@ function animate(element, options, counterpart, t2, on_begin, on_finish) {
 
 	const { delay = 0, css, tick, easing = linear } = options;
 
-	var keyframes = [];
+	/** @type {globalThis.Animation} */
+	var animation;
 
-	if (is_intro && counterpart === undefined) {
-		if (tick) {
-			tick(0, 1); // TODO put in nested effect, to avoid interleaved reads/writes?
-		}
+	var get_t = () => 1 - t2;
 
-		if (css) {
-			var styles = css_to_keyframe(css(0, 1));
-			keyframes.push(styles, styles);
-		}
-	}
+	// wait a microtask before applying the initial styles and creating the dummy animation,
+	// so that transitions created in the same batch (e.g. on nested elements) all measure
+	// the DOM first (#18421). this still happens before the next paint, so the element
+	// won't be rendered without styles applied (#14732)
+	queue_micro_task(() => {
+		if (aborted) return;
 
-	var get_t = () => 1 - t2;
+		var keyframes = [];
 
-	// create a dummy animation that lasts as long as the delay (but with whatever devtools
-	// multiplier is in effect). in the common case that it is `0`, we keep it anyway so that
-	// the CSS keyframes aren't created until the DOM is updated
-	//
-	// fill forwards to prevent the element from rendering without styles applied
-	// see https://github.com/sveltejs/svelte/issues/14732
-	var animation = element.animate(keyframes, { duration: delay, fill: 'forwards' });
+		if (is_intro && counterpart === undefined) {
+			if (tick) {
+				tick(0, 1); // TODO put in nested effect, to avoid interleaved reads/writes?
+			}
 
-	animation.onfinish = () => {
-		// remove dummy animation from the stack to prevent conflict with main animation
-		animation.cancel();
+			if (css) {
+				var styles = css_to_keyframe(css(0, 1));
+				keyframes.push(styles, styles);
+			}
+		}
 
-		on_begin();
+		// create a dummy animation that lasts as long as the delay (but with whatever devtools
+		// multiplier is in effect). in the common case that it is `0`, we keep it anyway so that
+		// the CSS keyframes aren't created until the DOM is updated
+		//
+		// fill forwards to prevent the element from rendering without styles applied
+		// see https://github.com/sveltejs/svelte/issues/14732
+		animation = element.animate(keyframes, { duration: delay, fill: 'forwards' });
 
-		// for bidirectional transitions, we start from the current position,
-		// rather than doing a full intro/outro
-		var t1 = counterpart?.t() ?? 1 - t2;
-		counterpart?.abort();
+		animation.onfinish = () => {
+			// remove dummy animation from the stack to prevent conflict with main animation
+			animation.cancel();
 
-		var delta = t2 - t1;
-		var duration = /** @type {number} */ (options.duration) * Math.abs(delta);
-		var keyframes = [];
+			on_begin();
 
-		if (duration > 0) {
-			/**
-			 * Whether or not the CSS includes `overflow: hidden`, in which case we need to
-			 * add it as an inline style to work around a Safari <18 bug
-			 * TODO 6.0 remove this, if possible
-			 */
-			var needs_overflow_hidden = false;
+			// for bidirectional transitions, we start from the current position,
+			// rather than doing a full intro/outro
+			var t1 = counterpart?.t() ?? 1 - t2;
+			counterpart?.abort();
 
-			if (css) {
-				var n = Math.ceil(duration / (1000 / 60)); // `n` must be an integer, or we risk missing the `t2` value
+			var delta = t2 - t1;
+			var duration = /** @type {number} */ (options.duration) * Math.abs(delta);
+			var keyframes = [];
+
+			if (duration > 0) {
+				/**
+				 * Whether or not the CSS includes `overflow: hidden`, in which case we need to
+				 * add it as an inline style to work around a Safari <18 bug
+				 * TODO 6.0 remove this, if possible
+				 */
+				var needs_overflow_hidden = false;
 
-				for (var i = 0; i <= n; i += 1) {
-					var t = t1 + delta * easing(i / n);
-					var styles = css_to_keyframe(css(t, 1 - t));
-					keyframes.push(styles);
+				if (css) {
+					var n = Math.ceil(duration / (1000 / 60)); // `n` must be an integer, or we risk missing the `t2` value
 
-					needs_overflow_hidden ||= styles.overflow === 'hidden';
+					for (var i = 0; i <= n; i += 1) {
+						var t = t1 + delta * easing(i / n);
+						var styles = css_to_keyframe(css(t, 1 - t));
+						keyframes.push(styles);
+
+						needs_overflow_hidden ||= styles.overflow === 'hidden';
+					}
 				}
-			}
 
-			if (needs_overflow_hidden) {
-				/** @type {HTMLElement} */ (element).style.overflow = 'hidden';
-			}
+				if (needs_overflow_hidden) {
+					/** @type {HTMLElement} */ (element).style.overflow = 'hidden';
+				}
 
-			get_t = () => {
-				var time = /** @type {number} */ (
-					/** @type {globalThis.Animation} */ (animation).currentTime
-				);
+				get_t = () => {
+					var time = /** @type {number} */ (
+						/** @type {globalThis.Animation} */ (animation).currentTime
+					);
 
-				return t1 + delta * easing(time / duration);
-			};
+					return t1 + delta * easing(time / duration);
+				};
 
-			if (tick) {
-				loop(() => {
-					if (animation.playState !== 'running') return false;
+				if (tick) {
+					loop(() => {
+						if (animation.playState !== 'running') return false;
 
-					var t = get_t();
-					tick(t, 1 - t);
+						var t = get_t();
+						tick(t, 1 - t);
 
-					return true;
-				});
+						return true;
+					});
+				}
 			}
-		}
 
-		animation = element.animate(keyframes, { duration, fill: 'forwards' });
+			animation = element.animate(keyframes, { duration, fill: 'forwards' });
 
-		animation.onfinish = () => {
-			get_t = () => t2;
-			tick?.(t2, 1 - t2);
-			on_finish();
+			animation.onfinish = () => {
+				get_t = () => t2;
+				tick?.(t2, 1 - t2);
+				on_finish();
+			};
 		};
-	};
+	});
 
 	return {
 		abort: () => {
+			aborted = true;
+
 			if (animation) {
 				animation.cancel();
 				// This prevents memory leaks in Chromium
diff --git a/packages/svelte/tests/runtime-browser/samples/transition-nested-measure/Nested.svelte b/packages/svelte/tests/runtime-browser/samples/transition-nested-measure/Nested.svelte
new file mode 100644
index 0000000000..eeb325059f
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/samples/transition-nested-measure/Nested.svelte
@@ -0,0 +1,14 @@
+<script>
+	import Nested from './Nested.svelte';
+	import { slide } from 'svelte/transition';
+
+	let { depth } = $props();
+</script>
+
+<div class="level-{depth}" in:slide|global={{ duration: 100 }}>
+	{#if depth > 0}
+		<Nested depth={depth - 1} />
+	{:else}
+		<div style="height: 100px">leaf</div>
+	{/if}
+</div>
diff --git a/packages/svelte/tests/runtime-browser/samples/transition-nested-measure/_config.js b/packages/svelte/tests/runtime-browser/samples/transition-nested-measure/_config.js
new file mode 100644
index 0000000000..00e5cb02a2
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/samples/transition-nested-measure/_config.js
@@ -0,0 +1,36 @@
+import { test } from '../../assert';
+
+export default test({
+	async test({ assert, target }) {
+		const button = target.querySelector('button');
+		button?.click();
+
+		// wait for the transition's keyframes to be created
+		const animation = await new Promise((resolve, reject) => {
+			const start = performance.now();
+
+			function check() {
+				const outer = target.querySelector('.level-2');
+				const animation = outer
+					?.getAnimations()
+					.find((a) => a.effect?.getTiming().duration === 100);
+
+				if (animation) {
+					resolve(animation);
+				} else if (performance.now() - start > 2000) {
+					reject(new Error('timed out waiting for the transition to start'));
+				} else {
+					requestAnimationFrame(check);
+				}
+			}
+
+			check();
+		});
+
+		// the outermost `slide` must have measured the element with its
+		// descendants at their natural size, not collapsed to zero by their
+		// own starting styles (#18421)
+		const keyframes = animation.effect?.getKeyframes() ?? [];
+		assert.equal(keyframes[keyframes.length - 1].height, '100px');
+	}
+});
diff --git a/packages/svelte/tests/runtime-browser/samples/transition-nested-measure/main.svelte b/packages/svelte/tests/runtime-browser/samples/transition-nested-measure/main.svelte
new file mode 100644
index 0000000000..a64a0cd2f4
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/samples/transition-nested-measure/main.svelte
@@ -0,0 +1,11 @@
+<script>
+	import Nested from './Nested.svelte';
+
+	let visible = $state(false);
+</script>
+
+<button onclick={() => (visible = !visible)}>toggle</button>
+
+{#if visible}
+	<Nested depth={2} />
+{/if}

From 0f458d5abaafaeaaeb15009700e6f7747c8f4121 Mon Sep 17 00:00:00 2001
From: Bao Nguyen <39545125+giaBaoJS@users.noreply.github.com>
Date: Tue, 25 Aug 2026 22:43:16 +0700
Subject: [PATCH 197/222] fix: report `derived_invalid_export` for `export let
 x = $derived(...)` (#18692)

Fixes #15842

Run the more targeted validations first

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/heavy-pumas-report.md              |  5 +++++
 .../visitors/ExportNamedDeclaration.js        | 20 +++++++++----------
 .../runes-export-let-derived/_config.js       |  9 +++++++++
 .../runes-export-let-derived/main.svelte      |  4 ++++
 4 files changed, 28 insertions(+), 10 deletions(-)
 create mode 100644 .changeset/heavy-pumas-report.md
 create mode 100644 packages/svelte/tests/compiler-errors/samples/runes-export-let-derived/_config.js
 create mode 100644 packages/svelte/tests/compiler-errors/samples/runes-export-let-derived/main.svelte

diff --git a/.changeset/heavy-pumas-report.md b/.changeset/heavy-pumas-report.md
new file mode 100644
index 0000000000..71a9422828
--- /dev/null
+++ b/.changeset/heavy-pumas-report.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: report `derived_invalid_export` for `export let x = $derived(...)` in runes mode
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/ExportNamedDeclaration.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/ExportNamedDeclaration.js
index 5b8d9ba053..dec6ebe2b4 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/ExportNamedDeclaration.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/ExportNamedDeclaration.js
@@ -1,4 +1,4 @@
-/** @import { ExportNamedDeclaration, Identifier } from 'estree' */
+/** @import { ExportNamedDeclaration, Identifier, VariableDeclaration } from 'estree' */
 /** @import { Context } from '../types' */
 import * as e from '../../../errors.js';
 import { extract_identifiers } from '../../../utils/ast.js';
@@ -23,15 +23,6 @@ export function ExportNamedDeclaration(node, context) {
 	}
 
 	if (node.declaration?.type === 'VariableDeclaration') {
-		// in runes mode, forbid `export let`
-		if (
-			context.state.analysis.runes &&
-			context.state.ast_type === 'instance' &&
-			node.declaration.kind === 'let'
-		) {
-			e.legacy_export_invalid(node);
-		}
-
 		for (const declarator of node.declaration.declarations) {
 			for (const id of extract_identifiers(declarator.id)) {
 				const binding = context.state.scope.get(id.name);
@@ -46,6 +37,15 @@ export function ExportNamedDeclaration(node, context) {
 				}
 			}
 		}
+
+		// in runes mode, forbid `export let`
+		if (
+			context.state.analysis.runes &&
+			context.state.ast_type === 'instance' &&
+			node.declaration.kind === 'let'
+		) {
+			e.legacy_export_invalid(node);
+		}
 	}
 
 	if (context.state.analysis.runes) {
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-export-let-derived/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-export-let-derived/_config.js
new file mode 100644
index 0000000000..852f56ebcc
--- /dev/null
+++ b/packages/svelte/tests/compiler-errors/samples/runes-export-let-derived/_config.js
@@ -0,0 +1,9 @@
+import { test } from '../../test';
+
+export default test({
+	error: {
+		code: 'derived_invalid_export',
+		message:
+			'Cannot export derived state from a module. To expose the current derived value, export a function returning its value'
+	}
+});
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-export-let-derived/main.svelte b/packages/svelte/tests/compiler-errors/samples/runes-export-let-derived/main.svelte
new file mode 100644
index 0000000000..512caf75f8
--- /dev/null
+++ b/packages/svelte/tests/compiler-errors/samples/runes-export-let-derived/main.svelte
@@ -0,0 +1,4 @@
+<script>
+	let count = $state(0);
+	export let double = $derived(count * 2);
+</script>

From bfc9b65b3d3c929046ba3ff594d4ae4ac300ffea Mon Sep 17 00:00:00 2001
From: Sushanth012 <146400678+Sushanth012@users.noreply.github.com>
Date: Tue, 25 Aug 2026 08:48:20 -0700
Subject: [PATCH 198/222] docs: clarify mounting components with context
 (#18515)

Closes #18462.
---
 documentation/docs/06-runtime/02-context.md | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/documentation/docs/06-runtime/02-context.md b/documentation/docs/06-runtime/02-context.md
index 439272df8f..a1e0347b7b 100644
--- a/documentation/docs/06-runtime/02-context.md
+++ b/documentation/docs/06-runtime/02-context.md
@@ -165,9 +165,9 @@ Svelte will warn you if you get it wrong.
 
 Similarly, to pass primitive values through context, use functions as described in [Passing state into functions]($state#Passing-state-into-functions).
 
-## Component testing
+## Mounting components with context
 
-When writing [component tests](testing#Unit-and-component-tests-with-Vitest-Component-testing), it can be useful to create a wrapper component that sets the context in order to check the behaviour of a component that uses it. As of version 5.49, you can do this sort of thing:
+To mount a component with specific context, create a wrapper component that sets the context before rendering the component. This is useful for [component tests](testing#Unit-and-component-tests-with-Vitest-Component-testing), or any other scenario that needs to provide context through `mount`. As of version 5.49, you can do this sort of thing:
 
 ```js
 import { mount, unmount } from 'svelte';
@@ -193,6 +193,8 @@ test('MyComponent', () => {
 
 This approach also works with [`hydrate`](imperative-component-api#hydrate) and [`render`](imperative-component-api#render).
 
+The context set by the wrapper only applies to that mounted component tree. Each call to `mount`, `hydrate` or `render` creates a separate wrapper instance, so the context does not leak into other mounted components.
+
 ## Replacing global state
 
 When you have state shared by many different components, you might be tempted to put it in its own module and just import it wherever it's needed:

From aadc97ce1be06e3dad4b98469ac385a07f34fd06 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Tue, 25 Aug 2026 12:06:14 -0400
Subject: [PATCH 199/222] fix: simplify boundary error handling and handle
 hydration errors correctly (#18539)

remove the `catch` clause in `this.#run` - in two locations there's already a catch, and in the hydration-location we have to add special handling for hydration errors.

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .../internal/client/dom/blocks/boundary.js    | 33 ++++++++++++-------
 .../async-error-boundary-5/Child.svelte       |  7 ++++
 .../samples/async-error-boundary-5/_config.js | 14 ++++++++
 .../async-error-boundary-5/main.svelte        | 24 ++++++++++++++
 4 files changed, 66 insertions(+), 12 deletions(-)
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-error-boundary-5/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-error-boundary-5/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-error-boundary-5/main.svelte

diff --git a/packages/svelte/src/internal/client/dom/blocks/boundary.js b/packages/svelte/src/internal/client/dom/blocks/boundary.js
index 4f655a3695..fd6bbdf5b4 100644
--- a/packages/svelte/src/internal/client/dom/blocks/boundary.js
+++ b/packages/svelte/src/internal/client/dom/blocks/boundary.js
@@ -1,14 +1,8 @@
 /** @import { Effect, Source, TemplateNode, } from '#client' */
-import {
-	BOUNDARY_EFFECT,
-	DIRTY,
-	EFFECT_PRESERVED,
-	EFFECT_TRANSPARENT,
-	MAYBE_DIRTY
-} from '#client/constants';
+import { BOUNDARY_EFFECT, EFFECT_PRESERVED, EFFECT_TRANSPARENT } from '#client/constants';
 import { HYDRATION_START_ELSE, HYDRATION_START_FAILED } from '../../../../constants.js';
 import { component_context, set_component_context } from '../../context.js';
-import { handle_error, invoke_error_boundary } from '../../error-handling.js';
+import { invoke_error_boundary } from '../../error-handling.js';
 import {
 	block,
 	branch,
@@ -271,13 +265,31 @@ export class Boundary {
 		queue_micro_task(() => {
 			var fragment = (this.#offscreen_fragment = document.createDocumentFragment());
 			var anchor = create_text();
+			var handled = false;
 
 			fragment.append(anchor);
 
 			this.#main_effect = this.#run(() => {
-				return branch(() => this.#children(anchor));
+				try {
+					return branch(() => this.#children(anchor));
+				} catch (error) {
+					try {
+						this.error(error);
+						handled = true;
+					} catch (error) {
+						invoke_error_boundary(error, this.#effect.parent);
+					}
+
+					return null;
+				}
 			});
 
+			if (this.#main_effect === null) {
+				this.#offscreen_fragment = null;
+				if (handled) this.#resolve(/** @type {Batch} */ (current_batch));
+				return;
+			}
+
 			if (this.#pending_count === 0) {
 				this.#anchor.before(fragment);
 				this.#offscreen_fragment = null;
@@ -362,9 +374,6 @@ export class Boundary {
 		try {
 			Batch.ensure();
 			return fn();
-		} catch (e) {
-			handle_error(e);
-			return null;
 		} finally {
 			set_active_effect(previous_effect);
 			set_active_reaction(previous_reaction);
diff --git a/packages/svelte/tests/runtime-runes/samples/async-error-boundary-5/Child.svelte b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-5/Child.svelte
new file mode 100644
index 0000000000..a49033a8cc
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-5/Child.svelte
@@ -0,0 +1,7 @@
+<script>
+	const { environment } = $props();
+
+	if (environment === 'client') {
+		throw new Error('oops');
+	}
+</script>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-error-boundary-5/_config.js b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-5/_config.js
new file mode 100644
index 0000000000..29e470e46f
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-5/_config.js
@@ -0,0 +1,14 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['hydrate'],
+	server_props: { environment: 'server' },
+	props: { environment: 'client' },
+	ssrHtml: 'loading inner loading nested',
+
+	async test({ assert, target }) {
+		await tick();
+		assert.htmlEqual(target.innerHTML, 'inner failed: oops outer failed: oops');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-error-boundary-5/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-5/main.svelte
new file mode 100644
index 0000000000..16a54630d0
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-5/main.svelte
@@ -0,0 +1,24 @@
+<script>
+	import Child from './Child.svelte';
+
+	const { environment } = $props();
+</script>
+
+<svelte:boundary>
+	<Child {environment} />
+	{await new Promise(() => {})}
+
+	{#snippet pending()}loading inner{/snippet}
+	{#snippet failed(error)}inner failed: {error.message}{/snippet}
+</svelte:boundary>
+
+<svelte:boundary>
+	<svelte:boundary>
+		<Child {environment} />
+		{await new Promise(() => {})}
+
+		{#snippet pending()}loading nested{/snippet}
+	</svelte:boundary>
+
+	{#snippet failed(error)}outer failed: {error.message}{/snippet}
+</svelte:boundary>

From 4d5139552dac8593c5e020846fa7ce8e96ea97b7 Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Tue, 25 Aug 2026 15:51:14 -0400
Subject: [PATCH 200/222] fix: block declaration tags on async values read
 inside closures (#18533)

Fixes #18469

Declaration tags collect blockers from `metadata.expression.dependencies`, which only sees eager reads, so a `$derived` reading an async declaration inside a closure gets no blocker and evaluates while the value is still `undefined`. Align with template expressions which already collect blockers from `references`

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/thick-plums-wave.md                  |  5 +++++
 .../phases/2-analyze/visitors/DeclarationTag.js |  3 ++-
 .../client/visitors/DeclarationTag.js           |  2 +-
 .../server/visitors/DeclarationTag.js           |  2 +-
 packages/svelte/tests/runtime-legacy/shared.ts  |  6 +++---
 .../samples/async-const-closure-read/_config.js | 10 ++++++++++
 .../async-const-closure-read/main.svelte        | 12 ++++++++++++
 .../async-declaration-closure-read/_config.js   | 11 +++++++++++
 .../async-declaration-closure-read/main.svelte  | 17 +++++++++++++++++
 9 files changed, 62 insertions(+), 6 deletions(-)
 create mode 100644 .changeset/thick-plums-wave.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-const-closure-read/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-const-closure-read/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-declaration-closure-read/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-declaration-closure-read/main.svelte

diff --git a/.changeset/thick-plums-wave.md b/.changeset/thick-plums-wave.md
new file mode 100644
index 0000000000..d8b454bb90
--- /dev/null
+++ b/.changeset/thick-plums-wave.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: block declaration tags and `{@const}` on async values read inside closures
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/DeclarationTag.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/DeclarationTag.js
index 52e9480838..2f72b16c72 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/DeclarationTag.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/DeclarationTag.js
@@ -43,7 +43,8 @@ export function DeclarationTag(node, context) {
  */
 export function mark_async_declaration(context, metadata, declarations) {
 	const has_await = metadata.expression.has_await;
-	const blockers = [...metadata.expression.dependencies]
+	// reads inside closures must block too, like they do in template expressions
+	const blockers = [...metadata.expression.references]
 		.map((dep) => dep.blocker)
 		.filter((b) => b !== null && b.object !== context.state.async_consts?.id);
 
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/DeclarationTag.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/DeclarationTag.js
index 3f78b53c90..ceb81a468d 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/DeclarationTag.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/DeclarationTag.js
@@ -71,7 +71,7 @@ export function add_async_declaration(context, metadata, ids, assignments, kind
 		context.state.consts.push(kind === 'var' ? b.var(id.name) : b.let(id.name));
 	}
 
-	const blockers = [...metadata.expression.dependencies]
+	const blockers = [...metadata.expression.references]
 		.map((dep) => dep.blocker)
 		.filter((b) => b !== null && b.object !== context.state.async_consts?.id);
 
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/DeclarationTag.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/DeclarationTag.js
index 8338700c0b..3fbff7167b 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/DeclarationTag.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/DeclarationTag.js
@@ -66,7 +66,7 @@ export function add_async_declaration(context, metadata, ids, assignments, kind
 		context.state.init.push(kind === 'var' ? b.var(id.name) : b.let(id.name));
 	}
 
-	const blockers = [...metadata.expression.dependencies]
+	const blockers = [...metadata.expression.references]
 		.map((dep) => dep.blocker)
 		.filter((b) => b !== null && b.object !== context.state.async_consts?.id);
 
diff --git a/packages/svelte/tests/runtime-legacy/shared.ts b/packages/svelte/tests/runtime-legacy/shared.ts
index 5c2d0dfe1c..de6749c0e7 100644
--- a/packages/svelte/tests/runtime-legacy/shared.ts
+++ b/packages/svelte/tests/runtime-legacy/shared.ts
@@ -177,11 +177,11 @@ export function runtime_suite(runes: boolean) {
 		['dom', 'hydrate', 'ssr', 'async-ssr'],
 		(variant, config, test_name) => {
 			if (!async_mode && (config.skip_no_async || test_name.startsWith('async-'))) {
-				return true;
+				return 'no-test';
 			}
 
 			if (async_mode && config.skip_async) {
-				return true;
+				return 'no-test';
 			}
 
 			if (variant === 'hydrate') {
@@ -195,9 +195,9 @@ export function runtime_suite(runes: boolean) {
 			) {
 				return 'no-test';
 			}
-
 			if (variant === 'ssr') {
 				if (
+					(test_name.startsWith('async-') && !config.mode?.includes('server')) ||
 					(config.mode && !config.mode.includes('server')) ||
 					(!config.test_ssr &&
 						config.html === undefined &&
diff --git a/packages/svelte/tests/runtime-runes/samples/async-const-closure-read/_config.js b/packages/svelte/tests/runtime-runes/samples/async-const-closure-read/_config.js
new file mode 100644
index 0000000000..be0e3c7f40
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-const-closure-read/_config.js
@@ -0,0 +1,10 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+// #18469 — a @const in a nested snippet reading an async declaration through a closure must block on it
+export default test({
+	async test({ assert, target }) {
+		await tick();
+		assert.htmlEqual(target.innerHTML, '<p>true</p> <p>false</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-const-closure-read/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-const-closure-read/main.svelte
new file mode 100644
index 0000000000..881455ec27
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-const-closure-read/main.svelte
@@ -0,0 +1,12 @@
+<script>
+	async function getValue() {
+		return new Set(['a', 'b', 'c']);
+	}
+
+	const value = await getValue();
+</script>
+
+{#each [['a', 'b'], ['a', 'x']] as keys}
+	{@const all_present = keys.every((k) => value.has(k))}
+	<p>{all_present}</p>
+{/each}
diff --git a/packages/svelte/tests/runtime-runes/samples/async-declaration-closure-read/_config.js b/packages/svelte/tests/runtime-runes/samples/async-declaration-closure-read/_config.js
new file mode 100644
index 0000000000..6a10f6928a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-declaration-closure-read/_config.js
@@ -0,0 +1,11 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+// #18469 — a sync $derived in a nested snippet reading an async declaration through a closure must block on it
+export default test({
+	ssrHtml: '<p>true</p> <p>false</p>',
+	async test({ assert, target }) {
+		await tick();
+		assert.htmlEqual(target.innerHTML, '<p>true</p> <p>false</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-declaration-closure-read/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-declaration-closure-read/main.svelte
new file mode 100644
index 0000000000..ddd9a10b04
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-declaration-closure-read/main.svelte
@@ -0,0 +1,17 @@
+<script>
+	async function getValue() {
+		return new Set(['a', 'b', 'c']);
+	}
+</script>
+
+{#snippet outer()}
+	{const value = $derived(await getValue())}
+	{#snippet inner(keys)}
+		{const all_present = $derived(keys.every((k) => value.has(k)))}
+		<p>{all_present}</p>
+	{/snippet}
+	{@render inner(['a', 'b'])}
+	{@render inner(['a', 'x'])}
+{/snippet}
+
+{@render outer()}

From 864de81bb67372af9783081b039d946dcdb5aabf Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Wed, 26 Aug 2026 04:10:48 -0400
Subject: [PATCH 201/222] fix: keep the current selection of a `<select>` when
 its `defaultValue` is applied (#18719)

Also ensure init_select isn't called multiple times

Follow-up to #18591.
---
 .../client/visitors/RegularElement.js         | 36 ++++++-----
 .../client/dom/elements/attributes.js         |  4 +-
 .../client/dom/elements/bindings/select.js    | 64 ++++++++++++-------
 .../form-default-value-select/_config.js      |  2 +-
 .../_config.js                                | 52 +++++++++++++++
 .../main.svelte                               | 37 +++++++++++
 .../_config.js                                | 30 +++++++++
 .../main.svelte                               | 21 ++++++
 8 files changed, 204 insertions(+), 42 deletions(-)
 create mode 100644 packages/svelte/tests/runtime-runes/samples/select-default-value-preserve-selection/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/select-default-value-preserve-selection/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/select-default-value-single-observer/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/select-default-value-single-observer/main.svelte

diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
index 401891b41b..adc9ec72dd 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
@@ -520,20 +520,28 @@ export function RegularElement(node, context) {
 	// deferred from the attribute loop above, so that the options it selects from
 	// have been created and had their values assigned
 	if (!has_spread && name === 'select') {
-		for (const attribute of /** @type {AST.Attribute[]} */ (attributes)) {
-			if (get_attribute_name(node, attribute) === 'defaultValue') {
-				const { value, has_state } = build_attribute_value(attribute.value, context, (v, m) =>
-					context.state.memoizer.add(v, m)
-				);
+		const default_value = /** @type {AST.Attribute[]} */ (attributes).find(
+			(attribute) => get_attribute_name(node, attribute) === 'defaultValue'
+		);
 
-				const update = b.stmt(b.call('$.set_default_select_value', node_id, value));
+		if (default_value) {
+			const { value, has_state } = build_attribute_value(default_value.value, context, (v, m) =>
+				context.state.memoizer.add(v, m)
+			);
 
-				(has_state ? context.state.update : context.state.init).push(update);
-				if (!bindings.has('value')) {
-					context.state.init.push(b.stmt(b.call('$.init_select', node_id)));
-				}
-				break;
-			}
+			(has_state ? context.state.update : context.state.init).push(
+				b.stmt(b.call('$.set_default_select_value', node_id, value))
+			);
+		}
+
+		const value_attribute = lookup.get('value');
+		const dynamic_value =
+			value_attribute !== undefined &&
+			value_attribute.value !== true &&
+			!is_text_attribute(value_attribute);
+
+		if (default_value || dynamic_value || bindings.has('value')) {
+			context.state.init.push(b.stmt(b.call('$.init_select', node_id)));
 		}
 	}
 
@@ -772,10 +780,6 @@ function build_element_special_value_attribute(
 	} else {
 		state.init.push(build_update(value));
 	}
-
-	if (is_select_with_value) {
-		state.init.push(b.stmt(b.call('$.init_select', node_id)));
-	}
 }
 
 /**
diff --git a/packages/svelte/src/internal/client/dom/elements/attributes.js b/packages/svelte/src/internal/client/dom/elements/attributes.js
index 7439db56e9..0fe1b8b2d3 100644
--- a/packages/svelte/src/internal/client/dom/elements/attributes.js
+++ b/packages/svelte/src/internal/client/dom/elements/attributes.js
@@ -525,7 +525,7 @@ export function attribute_effect(
 				var select = /** @type {HTMLSelectElement} */ (element);
 
 				if ('defaultValue' in next) {
-					set_default_select_value(select, next.defaultValue, false);
+					set_default_select_value(select, next.defaultValue);
 				}
 
 				if ('value' in next) {
@@ -558,7 +558,7 @@ export function attribute_effect(
 				var attrs = /** @type {Record<string | symbol, any>} */ (prev);
 
 				if ('defaultValue' in attrs) {
-					set_default_select_value(select, attrs.defaultValue, true);
+					set_default_select_value(select, attrs.defaultValue);
 				}
 
 				select_option(select, attrs.value, true);
diff --git a/packages/svelte/src/internal/client/dom/elements/bindings/select.js b/packages/svelte/src/internal/client/dom/elements/bindings/select.js
index fd1ebb92b8..cac7531ed2 100644
--- a/packages/svelte/src/internal/client/dom/elements/bindings/select.js
+++ b/packages/svelte/src/internal/client/dom/elements/bindings/select.js
@@ -20,33 +20,54 @@ export function set_selected(option, selected) {
 }
 
 /**
- * Sets the options a form reset should restore without changing the current selection.
- * The initial call is allowed to establish the current selection when no value exists.
+ * Sets the options a form reset should restore. The first call selects
+ * them if nothing has set a value, later calls leave the current selection alone.
  * @param {HTMLSelectElement} select
  * @param {any} value
- * @param {boolean} [mounting]
  */
-export function set_default_select_value(select, value, mounting = !('__defaultValue' in select)) {
-	// The DOM cannot recover unmatched, object or multiple defaults from selected options.
-	// Keep the requested value so option mutations can reapply it; property presence also
-	// distinguishes the initial application from later updates when the value is undefined.
+export function set_default_select_value(select, value) {
+	var mounting = !('__defaultValue' in select);
+	// @ts-expect-error
+	if (!mounting && select.__defaultValue === value) return;
 	// @ts-expect-error
 	select.__defaultValue = value;
-	var values = select.multiple ? (value == null ? [] : value) : null;
+	apply_default_select_value(select, !mounting || '__value' in select);
+}
 
-	if (select.multiple && !is_array(values)) return;
-	var selected = !mounting || '__value' in select ? new Set(select.selectedOptions) : null;
+/**
+ * Marks the options matching `__defaultValue` as selected. Without `preserve`
+ * a newly matching option gets selected, as an inserted `<option selected>` would.
+ * @param {HTMLSelectElement} select
+ * @param {boolean} preserve
+ */
+function apply_default_select_value(select, preserve) {
+	// @ts-expect-error
+	var value = select.__defaultValue;
+	var multiple = select.multiple;
+	var values = multiple ? value ?? [] : null;
+
+	if (multiple && !is_array(values)) return;
+
+	var index = select.selectedIndex;
+	var selected = preserve && multiple ? new Set(select.selectedOptions) : null;
 
 	for (var option of select.options) {
 		var option_value = get_option_value(option);
-		var is_selected = select.multiple
-			? /** @type {any[]} */ (values).includes(option_value)
-			: is(option_value, value);
-		set_selected(option, is_selected);
+		set_selected(
+			option,
+			multiple ? /** @type {any[]} */ (values).includes(option_value) : is(option_value, value)
+		);
 	}
 
+	if (!preserve) return;
+
 	if (selected !== null) {
-		for (option of select.options) option.selected = selected.has(option);
+		for (option of select.options) {
+			var was_selected = selected.has(option);
+			if (option.selected !== was_selected) option.selected = was_selected;
+		}
+	} else if (select.selectedIndex !== index) {
+		select.selectedIndex = index;
 	}
 }
 
@@ -91,11 +112,10 @@ export function select_option(select, value, mounting = false) {
 }
 
 /**
- * Selects the correct option(s) if `value` is given,
- * and then sets up a mutation observer to sync the
- * current selection to the dom when it changes. Such
- * changes could for example occur when options are
- * inside an `#each` block.
+ * Sets up a mutation observer to sync the current selection
+ * and default to the dom when the options change, for example
+ * when they are inside an `#each` block. Called once per `<select>`,
+ * by the compiled output or by `attribute_effect` for spreads.
  * @param {HTMLSelectElement} select
  */
 export function init_select(select) {
@@ -107,7 +127,7 @@ export function init_select(select) {
 		if (entries.every(is_selectedcontent_mutation)) return;
 
 		if ('__defaultValue' in select) {
-			set_default_select_value(select, select.__defaultValue, false);
+			apply_default_select_value(select, false);
 		}
 
 		if ('__value' in select) {
@@ -204,8 +224,6 @@ export function bind_select_value(select, get, set = get) {
 		select.__value = value;
 		mounting = false;
 	});
-
-	init_select(select);
 }
 
 /** @param {HTMLOptionElement} option */
diff --git a/packages/svelte/tests/runtime-runes/samples/form-default-value-select/_config.js b/packages/svelte/tests/runtime-runes/samples/form-default-value-select/_config.js
index 5d0c964969..784d20a0ce 100644
--- a/packages/svelte/tests/runtime-runes/samples/form-default-value-select/_config.js
+++ b/packages/svelte/tests/runtime-runes/samples/form-default-value-select/_config.js
@@ -62,7 +62,7 @@ export default test({
 		button('add').click();
 		flushSync();
 		await Promise.resolve();
-		check(selects[3], [true, false]);
+		check(selects[3], [false, true]);
 		assert.equal(selects[3].options[1].defaultSelected, true);
 
 		reset.click();
diff --git a/packages/svelte/tests/runtime-runes/samples/select-default-value-preserve-selection/_config.js b/packages/svelte/tests/runtime-runes/samples/select-default-value-preserve-selection/_config.js
new file mode 100644
index 0000000000..d409732ab8
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/select-default-value-preserve-selection/_config.js
@@ -0,0 +1,52 @@
+import { flushSync } from 'svelte';
+import { ok, test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		const [nothing, unmatched, spread, late, touched] = target.querySelectorAll('select');
+		const [change_default, change_spread, load, add] = target.querySelectorAll('button');
+		const p = target.querySelector('p');
+		ok(p);
+
+		assert.equal(nothing.selectedIndex, -1);
+		assert.equal(unmatched.selectedIndex, -1);
+		assert.equal(spread.selectedIndex, -1);
+		assert.equal(late.selectedIndex, -1);
+		assert.equal(touched.value, 'b');
+
+		change_default.click();
+		change_spread.click();
+		flushSync();
+
+		assert.equal(nothing.selectedIndex, -1);
+		assert.equal(unmatched.selectedIndex, -1);
+		assert.equal(spread.selectedIndex, -1);
+		assert.equal(spread.className, 'two');
+		assert.htmlEqual(p.innerHTML, 'zzz null');
+		assert.deepEqual(
+			[...nothing.options].map((option) => option.defaultSelected),
+			[true, false]
+		);
+
+		// a default change never moves the current selection
+		assert.equal(touched.value, 'b');
+
+		// a default whose option arrives later selects it
+		load.click();
+		flushSync();
+		await Promise.resolve();
+		assert.equal(late.value, 'b');
+
+		// a user selection survives option mutations and default changes
+		touched.options[2].selected = true;
+		touched.dispatchEvent(new Event('change', { bubbles: true }));
+		add.click();
+		flushSync();
+		await Promise.resolve();
+		assert.equal(touched.value, 'c');
+		assert.deepEqual(
+			[...touched.options].map((option) => option.defaultSelected),
+			[true, false, false, false]
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/select-default-value-preserve-selection/main.svelte b/packages/svelte/tests/runtime-runes/samples/select-default-value-preserve-selection/main.svelte
new file mode 100644
index 0000000000..c7fdea482c
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/select-default-value-preserve-selection/main.svelte
@@ -0,0 +1,37 @@
+<script>
+	let unmatched = $state('zzz');
+	let nothing = $state(null);
+	let defaultValue = $state('b');
+	let props = $state({ defaultValue: 'b', class: 'one' });
+	let late = $state([]);
+	let options = $state(['a', 'b', 'c']);
+</script>
+
+<select value={null} {defaultValue}>
+	<option value="a">A</option>
+	<option value="b">B</option>
+</select>
+
+<select bind:value={unmatched} {defaultValue}>
+	<option value="a">A</option>
+	<option value="b">B</option>
+</select>
+
+<select {...props} bind:value={nothing}>
+	<option value="a">A</option>
+	<option value="b">B</option>
+</select>
+
+<select defaultValue="b">
+	{#each late as option}<option value={option}>{option}</option>{/each}
+</select>
+
+<select {defaultValue}>
+	{#each options as option}<option value={option}>{option}</option>{/each}
+</select>
+
+<button onclick={() => (defaultValue = 'a')}>change default</button>
+<button onclick={() => (props.class = 'two')}>change class</button>
+<button onclick={() => (late = ['a', 'b', 'c'])}>load options</button>
+<button onclick={() => options.push('d')}>add option</button>
+<p>{unmatched} {String(nothing)}</p>
diff --git a/packages/svelte/tests/runtime-runes/samples/select-default-value-single-observer/_config.js b/packages/svelte/tests/runtime-runes/samples/select-default-value-single-observer/_config.js
new file mode 100644
index 0000000000..411a7868f7
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/select-default-value-single-observer/_config.js
@@ -0,0 +1,30 @@
+import { test } from '../../test';
+
+let observers = 0;
+const MutationObserver = globalThis.MutationObserver;
+
+export default test({
+	before_test() {
+		observers = 0;
+		globalThis.MutationObserver = class extends MutationObserver {
+			/** @param {MutationCallback} callback */
+			constructor(callback) {
+				super(callback);
+				observers++;
+			}
+		};
+	},
+
+	after_test() {
+		globalThis.MutationObserver = MutationObserver;
+	},
+
+	test({ assert, target }) {
+		const selects = target.querySelectorAll('select');
+		for (const select of selects) {
+			assert.equal(select.selectedIndex, 0);
+			assert.equal(select.options[1].defaultSelected, true);
+		}
+		assert.equal(observers, selects.length);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/select-default-value-single-observer/main.svelte b/packages/svelte/tests/runtime-runes/samples/select-default-value-single-observer/main.svelte
new file mode 100644
index 0000000000..7754b3c6fd
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/select-default-value-single-observer/main.svelte
@@ -0,0 +1,21 @@
+<script>
+	let value = $state('a');
+	let bound = $state('a');
+	let spread = $state('a');
+	let props = { defaultValue: 'b' };
+</script>
+
+<select {value} defaultValue="b">
+	<option value="a">A</option>
+	<option value="b">B</option>
+</select>
+
+<select bind:value={bound} defaultValue="b">
+	<option value="a">A</option>
+	<option value="b">B</option>
+</select>
+
+<select {...props} bind:value={spread}>
+	<option value="a">A</option>
+	<option value="b">B</option>
+</select>

From 2e8b57bc580b47004e4c48bf7dce11d4696ac785 Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Wed, 26 Aug 2026 04:11:35 -0400
Subject: [PATCH 202/222] fix: render `selected` options for `<select
 multiple>` with an array `value` on the server (#18720)

Follow-up to #18591.

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .../svelte/src/internal/server/renderer.js    | 19 ++++++-----
 .../binding-select-multiple/_config.js        | 33 +++++++++++++------
 .../select-multiple-value/_expected.html      |  5 +++
 .../samples/select-multiple-value/main.svelte |  5 +++
 4 files changed, 43 insertions(+), 19 deletions(-)
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/select-multiple-value/_expected.html
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/select-multiple-value/main.svelte

diff --git a/packages/svelte/src/internal/server/renderer.js b/packages/svelte/src/internal/server/renderer.js
index 240a7aa686..a30c302693 100644
--- a/packages/svelte/src/internal/server/renderer.js
+++ b/packages/svelte/src/internal/server/renderer.js
@@ -89,7 +89,7 @@ export class Renderer {
 	 * State that is local to the branch it is declared in.
 	 * It will be shallow-copied to all children.
 	 *
-	 * @type {{ select_value: any, select_default_multiple: boolean }}
+	 * @type {{ select_value: any, multiple: boolean }}
 	 */
 	local;
 
@@ -101,9 +101,7 @@ export class Renderer {
 		this.#parent = parent;
 
 		this.global = global;
-		this.local = parent
-			? { ...parent.local }
-			: { select_value: undefined, select_default_multiple: false };
+		this.local = parent ? { ...parent.local } : { select_value: undefined, multiple: false };
 		this.type = parent ? parent.type : 'body';
 	}
 
@@ -346,8 +344,7 @@ export class Renderer {
 		this.push(`<select${attributes(select_attrs, css_hash, classes, styles, flags)}>`);
 		this.child((renderer) => {
 			renderer.local.select_value = value === undefined ? defaultValue : value;
-			renderer.local.select_default_multiple =
-				value === undefined && Boolean(select_attrs.multiple);
+			renderer.local.multiple = !!select_attrs.multiple;
 			fn(renderer);
 		});
 		this.push(`${is_rich ? '<!>' : ''}</select>`);
@@ -375,10 +372,14 @@ export class Renderer {
 				value = attrs.value;
 			}
 
+			var select_value = this.local.select_value;
+
 			if (
-				this.local.select_default_multiple
-					? is_array(this.local.select_value) && this.local.select_value.includes(value)
-					: value === this.local.select_value
+				// Super edge-case, but theoretically someone could use arrays with non-multiple selects,
+				// so we gotta check for the multiple attribute presence, too.
+				this.local.multiple && is_array(select_value)
+					? select_value.includes(value)
+					: value === select_value
 			) {
 				renderer.#out.push(' selected=""');
 			}
diff --git a/packages/svelte/tests/runtime-legacy/samples/binding-select-multiple/_config.js b/packages/svelte/tests/runtime-legacy/samples/binding-select-multiple/_config.js
index 42c0e018e5..d7c1b8d339 100644
--- a/packages/svelte/tests/runtime-legacy/samples/binding-select-multiple/_config.js
+++ b/packages/svelte/tests/runtime-legacy/samples/binding-select-multiple/_config.js
@@ -6,17 +6,30 @@ export default test({
 		return { selected: ['two', 'three'] };
 	},
 
-	html: `
+	ssrHtml: `
 		<select multiple>
 			<option>one</option>
-			<option>two</option>
-			<option>three</option>
+			<option selected>two</option>
+			<option selected>three</option>
 		</select>
 
 		<p>selected: two, three</p>
 	`,
 
-	test({ assert, component, target, window }) {
+	test({ assert, component, target, window, variant }) {
+		const selected = variant === 'hydrate' ? ' selected' : '';
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+			<select multiple>
+				<option>one</option>
+				<option${selected}>two</option>
+				<option${selected}>three</option>
+			</select>
+
+			<p>selected: two, three</p>
+		`
+		);
 		const select = target.querySelector('select');
 		ok(select);
 		const options = [...target.querySelectorAll('option')];
@@ -33,8 +46,8 @@ export default test({
 			`
 			<select multiple>
 				<option>one</option>
-				<option>two</option>
-				<option>three</option>
+				<option${selected}>two</option>
+				<option${selected}>three</option>
 			</select>
 
 			<p>selected: three</p>
@@ -51,8 +64,8 @@ export default test({
 			`
 			<select multiple>
 				<option>one</option>
-				<option>two</option>
-				<option>three</option>
+				<option${selected}>two</option>
+				<option${selected}>three</option>
 			</select>
 
 			<p>selected: one, three</p>
@@ -70,8 +83,8 @@ export default test({
 			`
 			<select multiple>
 				<option>one</option>
-				<option>two</option>
-				<option>three</option>
+				<option${selected}>two</option>
+				<option${selected}>three</option>
 			</select>
 
 			<p>selected: one, two</p>
diff --git a/packages/svelte/tests/server-side-rendering/samples/select-multiple-value/_expected.html b/packages/svelte/tests/server-side-rendering/samples/select-multiple-value/_expected.html
new file mode 100644
index 0000000000..c0ab4a082e
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/select-multiple-value/_expected.html
@@ -0,0 +1,5 @@
+<select multiple="">
+	<option selected="" value="a">A</option>
+	<option value="b">B</option>
+	<option selected="" value="c">C</option>
+</select>
diff --git a/packages/svelte/tests/server-side-rendering/samples/select-multiple-value/main.svelte b/packages/svelte/tests/server-side-rendering/samples/select-multiple-value/main.svelte
new file mode 100644
index 0000000000..6bde3f597a
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/select-multiple-value/main.svelte
@@ -0,0 +1,5 @@
+<select multiple value={['a', 'c']}>
+	<option value="a">A</option>
+	<option value="b">B</option>
+	<option value="c">C</option>
+</select>

From 7c6f36aa924700baca30f8fb0f03dde4d46a1d21 Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Wed, 26 Aug 2026 04:19:59 -0400
Subject: [PATCH 203/222] fix: keep boolean attributes with an empty string
 value when rendering attribute objects on the server (#18721)

`<input disabled="" {...props}>` and any other boolean attribute written as `""` now renders on the server the way it does on the client and in plain markup.
---
 .changeset/ssr-empty-boolean-attribute.md              |  5 +++++
 packages/svelte/src/internal/shared/attributes.js      |  3 ++-
 .../empty-boolean-attribute-object/_expected.html      |  6 ++++++
 .../samples/empty-boolean-attribute-object/main.svelte | 10 ++++++++++
 4 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/ssr-empty-boolean-attribute.md
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/empty-boolean-attribute-object/_expected.html
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/empty-boolean-attribute-object/main.svelte

diff --git a/.changeset/ssr-empty-boolean-attribute.md b/.changeset/ssr-empty-boolean-attribute.md
new file mode 100644
index 0000000000..dbf5465014
--- /dev/null
+++ b/.changeset/ssr-empty-boolean-attribute.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: keep boolean attributes with an empty string value when rendering attribute objects on the server
diff --git a/packages/svelte/src/internal/shared/attributes.js b/packages/svelte/src/internal/shared/attributes.js
index bb1abf22c1..68994bf85e 100644
--- a/packages/svelte/src/internal/shared/attributes.js
+++ b/packages/svelte/src/internal/shared/attributes.js
@@ -27,7 +27,8 @@ export function attr(name, value, is_boolean = false) {
 	if (name === 'hidden' && value !== 'until-found') {
 		is_boolean = true;
 	}
-	if (value == null || (!value && is_boolean)) return '';
+	// `''` is a present boolean attribute, as it is in markup and on the client
+	if (value == null || (is_boolean && !value && value !== '')) return '';
 	const normalized =
 		(has_own_property.call(replacements, name) && replacements[name].get(value)) || value;
 	const assignment = is_boolean ? `=""` : `="${escape_html(normalized, true)}"`;
diff --git a/packages/svelte/tests/server-side-rendering/samples/empty-boolean-attribute-object/_expected.html b/packages/svelte/tests/server-side-rendering/samples/empty-boolean-attribute-object/_expected.html
new file mode 100644
index 0000000000..0c9cc0cd8c
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/empty-boolean-attribute-object/_expected.html
@@ -0,0 +1,6 @@
+<input disabled="">
+<input hidden="">
+<input>
+<select multiple="">
+	<option selected="" value="a">A</option>
+</select>
diff --git a/packages/svelte/tests/server-side-rendering/samples/empty-boolean-attribute-object/main.svelte b/packages/svelte/tests/server-side-rendering/samples/empty-boolean-attribute-object/main.svelte
new file mode 100644
index 0000000000..25af2b774d
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/empty-boolean-attribute-object/main.svelte
@@ -0,0 +1,10 @@
+<script>
+	const props = {};
+</script>
+
+<input disabled="" {...props} />
+<input hidden="" {...props} />
+<input disabled={false} {...props} />
+<select multiple="" value="a">
+	<option value="a">A</option>
+</select>

From 08c2a72907838f8466bfff91f1deff2dc1bccd57 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Wed, 26 Aug 2026 11:29:50 +0200
Subject: [PATCH 204/222] chore: set Vitest reporter for github actions
 (#18722)

test failures show up really bad now, minimal is way better for github actions
---
 vitest.config.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/vitest.config.js b/vitest.config.js
index 116dfae9d8..faabcfbea4 100644
--- a/vitest.config.js
+++ b/vitest.config.js
@@ -28,7 +28,7 @@ export default defineConfig({
 	},
 	test: {
 		dir: '.',
-		reporters: ['dot'],
+		reporters: process.env.GITHUB_ACTIONS === 'true' ? ['minimal'] : ['dot'],
 		// A handful of dev-mode tests trigger Svelte's `effect_update_depth_exceeded`
 		// guard, which involves ~1000 Error objects per flush for stack tracking —
 		// slow enough under vitest 4's deeper async stacks (and CI's slower workers)

From 05b69164d11aa241f16c9d3904d91fb4aa357970 Mon Sep 17 00:00:00 2001
From: Xia Chao <shapirolutts@gmail.com>
Date: Thu, 27 Aug 2026 21:44:40 +0800
Subject: [PATCH 205/222] fix: omit bind:focused from SSR output (#18724)

---------

Co-authored-by: Xia Chao <236466140+bun-unsafe@users.noreply.github.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/omit-bind-focused-ssr.md             | 5 +++++
 packages/svelte/src/compiler/phases/bindings.js | 4 +++-
 2 files changed, 8 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/omit-bind-focused-ssr.md

diff --git a/.changeset/omit-bind-focused-ssr.md b/.changeset/omit-bind-focused-ssr.md
new file mode 100644
index 0000000000..80200808aa
--- /dev/null
+++ b/.changeset/omit-bind-focused-ssr.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: omit `bind:focused` from SSR output (it has no HTML attribute)
diff --git a/packages/svelte/src/compiler/phases/bindings.js b/packages/svelte/src/compiler/phases/bindings.js
index 6714a6e77d..dfe78da98c 100644
--- a/packages/svelte/src/compiler/phases/bindings.js
+++ b/packages/svelte/src/compiler/phases/bindings.js
@@ -23,7 +23,9 @@ export const binding_properties = {
 		event: 'durationchange',
 		omit_in_ssr: true
 	},
-	focused: {},
+	focused: {
+		omit_in_ssr: true // no corresponding HTML attribute
+	},
 	paused: {
 		valid_elements: ['audio', 'video'],
 		omit_in_ssr: true,

From edbe11ebc93c26410867748a34c4ed311d128de0 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Thu, 27 Aug 2026 16:27:08 +0200
Subject: [PATCH 206/222] fix: properly apply static textarea value attribute
 during CSR (#18727)

Fixes #18574
Simpler alternative to #18627 - we just special-case this in the "should
this be treated as a dynamic attribute" branches so `$.set_value(...)`
is always generated. Given how edge-case-y this is (why would you not
just write it into the body of the textarea?) this is fine.
---
 .changeset/polite-zoos-melt.md                  |  5 +++++
 .../client/visitors/RegularElement.js           |  1 +
 .../samples/textarea-value/_config.js           | 17 +++++++++++------
 .../samples/textarea-value/main.svelte          |  3 ++-
 4 files changed, 19 insertions(+), 7 deletions(-)
 create mode 100644 .changeset/polite-zoos-melt.md

diff --git a/.changeset/polite-zoos-melt.md b/.changeset/polite-zoos-melt.md
new file mode 100644
index 0000000000..cfff0e82e4
--- /dev/null
+++ b/.changeset/polite-zoos-melt.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: properly apply static textarea value attribute during CSR
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
index adc9ec72dd..0a32e0dd53 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js
@@ -240,6 +240,7 @@ export function RegularElement(node, context) {
 			if (
 				!is_custom_element &&
 				!cannot_be_set_statically(attribute.name) &&
+				(name !== 'value' || node.name !== 'textarea') &&
 				(attribute.value === true || is_text_attribute(attribute)) &&
 				(name !== 'class' || class_directives.length === 0) &&
 				(name !== 'style' || style_directives.length === 0)
diff --git a/packages/svelte/tests/runtime-legacy/samples/textarea-value/_config.js b/packages/svelte/tests/runtime-legacy/samples/textarea-value/_config.js
index 06264b653b..30e2633154 100644
--- a/packages/svelte/tests/runtime-legacy/samples/textarea-value/_config.js
+++ b/packages/svelte/tests/runtime-legacy/samples/textarea-value/_config.js
@@ -5,14 +5,19 @@ export default test({
 		return { foo: 42 };
 	},
 
-	html: '<textarea></textarea>',
-	ssrHtml: '<textarea>42</textarea>',
+	ssrHtml: '<textarea>42</textarea> <textarea>static</textarea>',
 
-	test({ assert, component, target }) {
-		const textarea = /** @type {HTMLTextAreaElement} */ (target.querySelector('textarea'));
-		assert.strictEqual(textarea.value, '42');
+	test({ assert, component, target, variant }) {
+		assert.htmlEqual(
+			target.innerHTML,
+			`<textarea></textarea> <textarea>${variant === 'hydrate' ? 'static' : ''}</textarea>`
+		);
+
+		const [textarea1, textarea2] = target.querySelectorAll('textarea');
+		assert.strictEqual(textarea1.value, '42');
+		assert.strictEqual(textarea2.value, 'static');
 
 		component.foo = 43;
-		assert.strictEqual(textarea.value, '43');
+		assert.strictEqual(textarea1.value, '43');
 	}
 });
diff --git a/packages/svelte/tests/runtime-legacy/samples/textarea-value/main.svelte b/packages/svelte/tests/runtime-legacy/samples/textarea-value/main.svelte
index 7eaf783f7f..203a3ed039 100644
--- a/packages/svelte/tests/runtime-legacy/samples/textarea-value/main.svelte
+++ b/packages/svelte/tests/runtime-legacy/samples/textarea-value/main.svelte
@@ -2,4 +2,5 @@
 	export let foo;
 </script>
 
-<textarea value='{foo}'/>
\ No newline at end of file
+<textarea value='{foo}'/>
+<textarea value="static"></textarea>

From 74197ccbe1d84cab76c1eefbf3def43903661691 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Thu, 27 Aug 2026 17:05:23 +0200
Subject: [PATCH 207/222] feat: add getOrInsert/getOrInsertComputed to
 SvelteMap (#18728)

Closes #18014
---
 .changeset/tasty-years-hammer.md           |  5 ++
 packages/svelte/src/reactivity/map.js      | 22 ++++++
 packages/svelte/src/reactivity/map.test.ts | 79 ++++++++++++++++++++++
 packages/svelte/types/index.d.ts           |  4 ++
 4 files changed, 110 insertions(+)
 create mode 100644 .changeset/tasty-years-hammer.md

diff --git a/.changeset/tasty-years-hammer.md b/.changeset/tasty-years-hammer.md
new file mode 100644
index 0000000000..42b559ac9f
--- /dev/null
+++ b/.changeset/tasty-years-hammer.md
@@ -0,0 +1,5 @@
+---
+'svelte': minor
+---
+
+feat: add getOrInsert/getOrInsertComputed to SvelteMap
diff --git a/packages/svelte/src/reactivity/map.js b/packages/svelte/src/reactivity/map.js
index 48d06a05a7..935db8fcb1 100644
--- a/packages/svelte/src/reactivity/map.js
+++ b/packages/svelte/src/reactivity/map.js
@@ -153,6 +153,28 @@ export class SvelteMap extends Map {
 		return super.get(key);
 	}
 
+	/**
+	 * @param {K} key
+	 * @param {V} value
+	 * */
+	getOrInsert(key, value) {
+		if (!super.has(key)) {
+			this.set(key, value);
+		}
+		return /** @type {V} */ (this.get(key));
+	}
+
+	/**
+	 * @param {K} key
+	 * @param {(key: K) => V} callbackFn
+	 */
+	getOrInsertComputed(key, callbackFn) {
+		if (!super.has(key)) {
+			this.set(key, callbackFn(key));
+		}
+		return /** @type {V} */ (this.get(key));
+	}
+
 	/**
 	 * @param {K} key
 	 * @param {V} value
diff --git a/packages/svelte/src/reactivity/map.test.ts b/packages/svelte/src/reactivity/map.test.ts
index 8bb6f72f7b..f5cbb21923 100644
--- a/packages/svelte/src/reactivity/map.test.ts
+++ b/packages/svelte/src/reactivity/map.test.ts
@@ -100,6 +100,85 @@ test('map.get(...)', () => {
 	cleanup();
 });
 
+test('map.getOrInsert(...)', () => {
+	const map = new SvelteMap([
+		[2, 2],
+		[3, 3]
+	]);
+
+	const log: any = [];
+
+	const cleanup = effect_root(() => {
+		render_effect(() => {
+			log.push('get 1', map.getOrInsert(1, 1));
+		});
+
+		render_effect(() => {
+			log.push('get 2', map.getOrInsert(2, 2));
+		});
+
+		render_effect(() => {
+			log.push('get 3', map.getOrInsert(3, 4));
+		});
+	});
+
+	flushSync(() => {
+		map.delete(2);
+	});
+
+	flushSync(() => {
+		map.set(2, 2);
+	});
+
+	assert.deepEqual(log, ['get 1', 1, 'get 2', 2, 'get 3', 3, 'get 2', 2]);
+
+	cleanup();
+});
+
+test('map.getOrInsertComputed(...)', () => {
+	const map = new SvelteMap([
+		[2, 2],
+		[3, 3]
+	]);
+
+	const log: any = [];
+
+	const cleanup = effect_root(() => {
+		render_effect(() => {
+			log.push(
+				'get 1',
+				map.getOrInsertComputed(1, (k) => k)
+			);
+		});
+
+		render_effect(() => {
+			log.push(
+				'get 2',
+				map.getOrInsertComputed(2, (k) => k)
+			);
+		});
+
+		render_effect(() => {
+			log.push(
+				'get 3',
+				map.getOrInsertComputed(3, () => 4)
+			);
+		});
+	});
+
+	flushSync(() => {
+		map.delete(2);
+	});
+
+	flushSync(() => {
+		map.set(2, 2);
+	});
+
+	assert.deepEqual(log, ['get 1', 1, 'get 2', 2, 'get 3', 3, 'get 2', 2]);
+
+	cleanup();
+});
+
 test('map.has(...)', () => {
 	const map = new SvelteMap([
 		[1, 1],
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index dcc6dc5914..9e69796691 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -2466,6 +2466,10 @@ declare module 'svelte/reactivity' {
 		
 		constructor(value?: Iterable<readonly [K, V]> | null | undefined);
 		
+		getOrInsert(key: K, value: V): V;
+		
+		getOrInsertComputed(key: K, callbackFn: (key: K) => V): V;
+		
 		set(key: K, value: V): this;
 		#private;
 	}

From 5034b59e9e6cff42451d9136650f5fbde4c25260 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Thu, 27 Aug 2026 22:38:50 +0200
Subject: [PATCH 208/222] chore: bump playwright (#18729)

supports later ubuntu versions
---
 package.json                 |  2 +-
 packages/svelte/package.json |  2 +-
 pnpm-lock.yaml               | 66 ++++++++++++++++++++++++++----------
 3 files changed, 50 insertions(+), 20 deletions(-)

diff --git a/package.json b/package.json
index 16fc26bc32..8004698dd1 100644
--- a/package.json
+++ b/package.json
@@ -37,7 +37,7 @@
     "eslint-plugin-lube": "^0.5.1",
     "eslint-plugin-svelte": "^3.15.0",
     "jsdom": "25.0.1",
-    "playwright": "^1.60.0",
+    "playwright": "^1.62.0",
     "prettier": "^3.2.4",
     "prettier-plugin-svelte": "^3.4.0",
     "svelte": "workspace:^",
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 2da4ee428d..1f85001520 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -152,7 +152,7 @@
   },
   "devDependencies": {
     "@jridgewell/trace-mapping": "^0.3.25",
-    "@playwright/test": "^1.60.0",
+    "@playwright/test": "^1.62.0",
     "@rollup/plugin-commonjs": "^28.0.1",
     "@rollup/plugin-node-resolve": "^15.3.0",
     "@rollup/plugin-terser": "^0.4.4",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 70dcf70e5b..9224650e7d 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -42,8 +42,8 @@ importers:
         specifier: 25.0.1
         version: 25.0.1
       playwright:
-        specifier: ^1.60.0
-        version: 1.60.0
+        specifier: ^1.62.0
+        version: 1.62.1
       prettier:
         specifier: ^3.2.4
         version: 3.2.4
@@ -121,8 +121,8 @@ importers:
         specifier: ^0.3.25
         version: 0.3.31
       '@playwright/test':
-        specifier: ^1.60.0
-        version: 1.60.0
+        specifier: ^1.62.0
+        version: 1.62.1
       '@rollup/plugin-commonjs':
         specifier: ^28.0.1
         version: 28.0.1(rollup@4.60.1)
@@ -723,9 +723,9 @@ packages:
     resolution: {integrity: sha512-oGB+UxlgWcgQkgwo8GcEGwemoTFt3FIO9ababBmaGwXIoBKZ+GTy0pP185beGg7Llih/NSHSV2XAs1lnznocSg==}
     engines: {node: '>= 8'}
 
-  '@playwright/test@1.60.0':
-    resolution: {integrity: sha512-O71yZIbAh/PxDMNGns37GHBIfrVkEVyn+AXyIa5dOTfb4/xNvRWV+Vv/NMbNCtODB/pO7vLlF2OTmMVLhmr7Ag==}
-    engines: {node: '>=18'}
+  '@playwright/test@1.62.1':
+    resolution: {integrity: sha512-DTcUc8qii+cpHvtOwggMtBRMjKZHXYWdw8syRYu2vtzuq4Wxphqq4NfCs5Zt44L6mA8rfDfj+PHnxFc/FeK6mQ==}
+    engines: {node: '>=20'}
     hasBin: true
 
   '@polka/url@1.0.0-next.25':
@@ -840,131 +840,157 @@ packages:
     resolution: {integrity: sha512-L+34Qqil+v5uC0zEubW7uByo78WOCIrBvci69E7sFASRl0X7b/MB6Cqd1lky/CtcSVTydWa2WZwFuWexjS5o6g==}
     cpu: [arm]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-arm-gnueabihf@4.62.2':
     resolution: {integrity: sha512-n1GJHPOvpIfhi3TmrCeh6S6URt9BFCt0KQE3qvexyGCTAKpR4Lg+eWvNZEqu7epxwus/8ElT3hacYEucm49SZg==}
     cpu: [arm]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-arm-musleabihf@4.60.1':
     resolution: {integrity: sha512-n83O8rt4v34hgFzlkb1ycniJh7IR5RCIqt6mz1VRJD6pmhRi0CXdmfnLu9dIUS6buzh60IvACM842Ffb3xd6Gg==}
     cpu: [arm]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-linux-arm-musleabihf@4.62.2':
     resolution: {integrity: sha512-JqgflS8wEB+UXV/vS1RpRbifGBeN4D5lz8D8oOFbFZw4vedvdOgCFAjfBmIMdW3yL10XpQQ0Ambepw6MXrhOnA==}
     cpu: [arm]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-linux-arm64-gnu@4.60.1':
     resolution: {integrity: sha512-Nql7sTeAzhTAja3QXeAI48+/+GjBJ+QmAH13snn0AJSNL50JsDqotyudHyMbO2RbJkskbMbFJfIJKWA6R1LCJQ==}
     cpu: [arm64]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-arm64-gnu@4.62.2':
     resolution: {integrity: sha512-wnFJkogWvN4jm/hQRF2UBaeUmk20j5+DmHvoyWii2b8HJDyvz1MF2OU/6ynXt2KR63rbZLWkFpoytpdc/yBuSA==}
     cpu: [arm64]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-arm64-musl@4.60.1':
     resolution: {integrity: sha512-+pUymDhd0ys9GcKZPPWlFiZ67sTWV5UU6zOJat02M1+PiuSGDziyRuI/pPue3hoUwm2uGfxdL+trT6Z9rxnlMA==}
     cpu: [arm64]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-linux-arm64-musl@4.62.2':
     resolution: {integrity: sha512-HVu2bp0zhvJ8xHEV9+UUs7S90VadmBSY3LcIMvozbPo4AuMGDWlz3ymHLHZPX4hR67TKTt8Qp5PJ5RBg/i+RMQ==}
     cpu: [arm64]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-linux-loong64-gnu@4.60.1':
     resolution: {integrity: sha512-VSvgvQeIcsEvY4bKDHEDWcpW4Yw7BtlKG1GUT4FzBUlEKQK0rWHYBqQt6Fm2taXS+1bXvJT6kICu5ZwqKCnvlQ==}
     cpu: [loong64]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-loong64-gnu@4.62.2':
     resolution: {integrity: sha512-mQqqAV8QaoSgr9I2fKDLY2BAVvmKjWoGiu/cSYQonsLvtqwEn1E4QYfnCOcp5zoEqNhsDYin1s6jx/VJmrxlZg==}
     cpu: [loong64]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-loong64-musl@4.60.1':
     resolution: {integrity: sha512-4LqhUomJqwe641gsPp6xLfhqWMbQV04KtPp7/dIp0nzPxAkNY1AbwL5W0MQpcalLYk07vaW9Kp1PBhdpZYYcEw==}
     cpu: [loong64]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-linux-loong64-musl@4.62.2':
     resolution: {integrity: sha512-IxKLoxCQ2IWi6bT2akyDUBGsOImDKB+sPp4EsTmwFQ/fMwpCKm8uLSSgP/Kx/QYUgKis6SEZ5/Nlhup0DIA0PQ==}
     cpu: [loong64]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-linux-ppc64-gnu@4.60.1':
     resolution: {integrity: sha512-tLQQ9aPvkBxOc/EUT6j3pyeMD6Hb8QF2BTBnCQWP/uu1lhc9AIrIjKnLYMEroIz/JvtGYgI9dF3AxHZNaEH0rw==}
     cpu: [ppc64]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-ppc64-gnu@4.62.2':
     resolution: {integrity: sha512-Mk5ha2RQSgyFfmYYLkBpPnUk8D8FriBxesO1u9O75X0mHgXL1UQcH5Itl2lurWL2tj0RxV9b9tJgipac0hRY9A==}
     cpu: [ppc64]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-ppc64-musl@4.60.1':
     resolution: {integrity: sha512-RMxFhJwc9fSXP6PqmAz4cbv3kAyvD1etJFjTx4ONqFP9DkTkXsAMU4v3Vyc5BgzC+anz7nS/9tp4obsKfqkDHg==}
     cpu: [ppc64]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-linux-ppc64-musl@4.62.2':
     resolution: {integrity: sha512-CjvEnqJL/0/TQ3TXX3OPIJ/kmBellrWd4heXUmHeJlTnmwjKpSJzoehLaL6Xk0ZnMHBu9dZuFADNOrtjF4v+2w==}
     cpu: [ppc64]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-linux-riscv64-gnu@4.60.1':
     resolution: {integrity: sha512-QKgFl+Yc1eEk6MmOBfRHYF6lTxiiiV3/z/BRrbSiW2I7AFTXoBFvdMEyglohPj//2mZS4hDOqeB0H1ACh3sBbg==}
     cpu: [riscv64]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-riscv64-gnu@4.62.2':
     resolution: {integrity: sha512-1SiZbzwdkaDURsew/tSOrooKiYy7EQGT6m8ufavAi9NEyQb/6VuIxFXAL1fqa4iZe3g4NbNk4P7J32z2tw5Mgg==}
     cpu: [riscv64]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-riscv64-musl@4.60.1':
     resolution: {integrity: sha512-RAjXjP/8c6ZtzatZcA1RaQr6O1TRhzC+adn8YZDnChliZHviqIjmvFwHcxi4JKPSDAt6Uhf/7vqcBzQJy0PDJg==}
     cpu: [riscv64]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-linux-riscv64-musl@4.62.2':
     resolution: {integrity: sha512-nQts12zJ3NQRoE6uYljOH89v7szzLDvG2JD/vsX+vGXU8w/At1GowTZ5/7qeFQ8m7L55rpR8Okugnuo5bgjy2Q==}
     cpu: [riscv64]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-linux-s390x-gnu@4.60.1':
     resolution: {integrity: sha512-wcuocpaOlaL1COBYiA89O6yfjlp3RwKDeTIA0hM7OpmhR1Bjo9j31G1uQVpDlTvwxGn2nQs65fBFL5UFd76FcQ==}
     cpu: [s390x]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-s390x-gnu@4.62.2':
     resolution: {integrity: sha512-E9/ll019jhPIJgpzfZoIkBGhcz+kKNgVWYRY0zr9srBdPPFVpvOKW8VaJKUbeK+eZXyQF9ltME+Kk6affeaPgg==}
     cpu: [s390x]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-x64-gnu@4.60.1':
     resolution: {integrity: sha512-77PpsFQUCOiZR9+LQEFg9GClyfkNXj1MP6wRnzYs0EeWbPcHs02AXu4xuUbM1zhwn3wqaizle3AEYg5aeoohhg==}
     cpu: [x64]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-x64-gnu@4.62.2':
     resolution: {integrity: sha512-5BqxR/pshjey51iliyzTD5Xi3EN0aLmQ2lZ3lvefVV9c82BvrLo2/6OT55iifpWBufs6kdwWbuOKS841DrmK9A==}
     cpu: [x64]
     os: [linux]
+    libc: [glibc]
 
   '@rollup/rollup-linux-x64-musl@4.60.1':
     resolution: {integrity: sha512-5cIATbk5vynAjqqmyBjlciMJl1+R/CwX9oLk/EyiFXDWd95KpHdrOJT//rnUl4cUcskrd0jCCw3wpZnhIHdD9w==}
     cpu: [x64]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-linux-x64-musl@4.62.2':
     resolution: {integrity: sha512-uNN83XxQrRAh/w0/pmAfibcwyb6YWt4gP+dpnQKPVJshAloQ785ii8CT8ZCIxkGg9opVsvAlGhFitSm6D1Jjpg==}
     cpu: [x64]
     os: [linux]
+    libc: [musl]
 
   '@rollup/rollup-openbsd-x64@4.60.1':
     resolution: {integrity: sha512-cl0w09WsCi17mcmWqqglez9Gk8isgeWvoUZ3WiJFYSR3zjBQc2J5/ihSjpl+VLjPqjQ/1hJRcqBfLjssREQILw==}
@@ -1875,24 +1901,28 @@ packages:
     engines: {node: '>= 12.0.0'}
     cpu: [arm64]
     os: [linux]
+    libc: [glibc]
 
   lightningcss-linux-arm64-musl@1.23.0:
     resolution: {integrity: sha512-cU00LGb6GUXCwof6ACgSMKo3q7XYbsyTj0WsKHLi1nw7pV0NCq8nFTn6ZRBYLoKiV8t+jWl0Hv8KkgymmK5L5g==}
     engines: {node: '>= 12.0.0'}
     cpu: [arm64]
     os: [linux]
+    libc: [musl]
 
   lightningcss-linux-x64-gnu@1.23.0:
     resolution: {integrity: sha512-q4jdx5+5NfB0/qMbXbOmuC6oo7caPnFghJbIAV90cXZqgV8Am3miZhC4p+sQVdacqxfd+3nrle4C8icR3p1AYw==}
     engines: {node: '>= 12.0.0'}
     cpu: [x64]
     os: [linux]
+    libc: [glibc]
 
   lightningcss-linux-x64-musl@1.23.0:
     resolution: {integrity: sha512-G9Ri3qpmF4qef2CV/80dADHKXRAQeQXpQTLx7AiQrBYQHqBjB75oxqj06FCIe5g4hNCqLPnM9fsO4CyiT1sFSQ==}
     engines: {node: '>= 12.0.0'}
     cpu: [x64]
     os: [linux]
+    libc: [musl]
 
   lightningcss-win32-x64-msvc@1.23.0:
     resolution: {integrity: sha512-1rcBDJLU+obPPJM6qR5fgBUiCdZwZLafZM5f9kwjFLkb/UBNIzmae39uCSmh71nzPCTXZqHbvwu23OWnWEz+eg==}
@@ -2077,14 +2107,14 @@ packages:
     resolution: {integrity: sha512-uB80kBFb/tfd68bVleG9T5GGsGPjJrLAUpR5PZIrhBnIaRTQRjqdJSsIKkOP6OAIFbj7GOrcudc5pNjZ+geV2g==}
     engines: {node: '>=6'}
 
-  playwright-core@1.60.0:
-    resolution: {integrity: sha512-9bW6zvX/m0lEbgTKJ6YppOKx8H3VOPBMOCFh2irXFOT4BbHgrx5hPjwJYLT40Lu+4qtD36qKc/Hn56StUW57IA==}
-    engines: {node: '>=18'}
+  playwright-core@1.62.1:
+    resolution: {integrity: sha512-wPYSwEBJY9GHraISXqyqtx0na0LpO3XEX7jNDhntbex7tzUS7kLnZsOlFruFJB4Hi/rhDMjXGqHewDZ68nYZVw==}
+    engines: {node: '>=20'}
     hasBin: true
 
-  playwright@1.60.0:
-    resolution: {integrity: sha512-hheHdokM8cdqCb0lcE3s+zT4t4W+vvjpGxsZlDnikarzx8tSzMebh3UiFtgqwFwnTnjYQcsyMF8ei2mCO/tpeA==}
-    engines: {node: '>=18'}
+  playwright@1.62.1:
+    resolution: {integrity: sha512-0M+L3LAD8/nm554LOla9Ayx0j0tmFZ0FBcoQ7F1VuVHpM/XpiC8RcDzBQB8W5+hA8L22THxELzeF+2WcUzvcLg==}
+    engines: {node: '>=20'}
     hasBin: true
 
   polka@1.0.0-next.25:
@@ -3069,9 +3099,9 @@ snapshots:
       '@nodelib/fs.scandir': 2.1.5
       fastq: 1.16.0
 
-  '@playwright/test@1.60.0':
+  '@playwright/test@1.62.1':
     dependencies:
-      playwright: 1.60.0
+      playwright: 1.62.1
 
   '@polka/url@1.0.0-next.25': {}
 
@@ -4371,11 +4401,11 @@ snapshots:
 
   pify@4.0.1: {}
 
-  playwright-core@1.60.0: {}
+  playwright-core@1.62.1: {}
 
-  playwright@1.60.0:
+  playwright@1.62.1:
     dependencies:
-      playwright-core: 1.60.0
+      playwright-core: 1.62.1
     optionalDependencies:
       fsevents: 2.3.2
 

From 4ae5eb3f23df00de4d60bf40ff5a96580a0719dc Mon Sep 17 00:00:00 2001
From: Adnane Taghi <taghi.adnane@proton.me>
Date: Thu, 27 Aug 2026 21:58:40 +0100
Subject: [PATCH 209/222] feat: add has function to createContext (#18472)

closes #18471.

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/short-feet-admire.md                    |  5 +++++
 documentation/docs/06-runtime/02-context.md        |  2 +-
 .../docs/98-reference/.generated/shared-errors.md  |  2 +-
 packages/svelte/messages/shared-errors/errors.md   |  2 +-
 packages/svelte/src/internal/client/context.js     |  6 +++---
 packages/svelte/src/internal/server/context.js     |  4 ++--
 packages/svelte/src/internal/shared/context.js     |  5 +++--
 .../create-context-programmatic/Child.svelte       |  8 +++++++-
 .../samples/create-context-programmatic/_config.js |  2 +-
 .../create-context-programmatic/main.svelte        | 14 +++++++++-----
 .../samples/create-context/Child.svelte            |  8 +++++++-
 .../samples/create-context/_config.js              |  2 +-
 .../samples/create-context/main.svelte             |  6 ++++--
 packages/svelte/types/index.d.ts                   |  4 ++--
 14 files changed, 47 insertions(+), 23 deletions(-)
 create mode 100644 .changeset/short-feet-admire.md

diff --git a/.changeset/short-feet-admire.md b/.changeset/short-feet-admire.md
new file mode 100644
index 0000000000..fdf56477c9
--- /dev/null
+++ b/.changeset/short-feet-admire.md
@@ -0,0 +1,5 @@
+---
+'svelte': minor
+---
+
+feat: add `has` function to `createContext`
diff --git a/documentation/docs/06-runtime/02-context.md b/documentation/docs/06-runtime/02-context.md
index a1e0347b7b..f67339c6cf 100644
--- a/documentation/docs/06-runtime/02-context.md
+++ b/documentation/docs/06-runtime/02-context.md
@@ -4,7 +4,7 @@ title: Context
 
 Context allows components to access values owned by parent components without passing them down as props (potentially through many layers of intermediate components, known as 'prop-drilling').
 
-By creating a `[get, set]` pair of functions with `createContext`, you can set the context in a parent component and get it in a child component:
+By creating a `[get, set, has]` triplet of functions with `createContext`, you can set the context in a parent component and get it in a child component:
 
 <!-- codeblock:start {"title":"Context","selected":"context.ts"} -->
 ```svelte
diff --git a/documentation/docs/98-reference/.generated/shared-errors.md b/documentation/docs/98-reference/.generated/shared-errors.md
index d7596fc068..44616d7c8d 100644
--- a/documentation/docs/98-reference/.generated/shared-errors.md
+++ b/documentation/docs/98-reference/.generated/shared-errors.md
@@ -78,7 +78,7 @@ Certain lifecycle methods can only be used during component initialisation. To f
 Context was not set in the current component or any of its ancestors
 ```
 
-The [`createContext()`](svelte#createContext) utility returns a `[get, set]` pair of functions. `get` will throw an error if `set` was not used to set the context in the current component or any of its ancestors.
+The [`createContext()`](svelte#createContext) utility returns a `[get, set, has]` triplet of functions. `get` will throw an error if `set` was not used to set the context in the current component or any of its ancestors.
 
 ### snippet_without_render_tag
 
diff --git a/packages/svelte/messages/shared-errors/errors.md b/packages/svelte/messages/shared-errors/errors.md
index 43dca57ac8..e005e34fc8 100644
--- a/packages/svelte/messages/shared-errors/errors.md
+++ b/packages/svelte/messages/shared-errors/errors.md
@@ -64,7 +64,7 @@ Certain lifecycle methods can only be used during component initialisation. To f
 
 > Context was not set in the current component or any of its ancestors
 
-The [`createContext()`](svelte#createContext) utility returns a `[get, set]` pair of functions. `get` will throw an error if `set` was not used to set the context in the current component or any of its ancestors.
+The [`createContext()`](svelte#createContext) utility returns a `[get, set, has]` triplet of functions. `get` will throw an error if `set` was not used to set the context in the current component or any of its ancestors.
 
 ## snippet_without_render_tag
 
diff --git a/packages/svelte/src/internal/client/context.js b/packages/svelte/src/internal/client/context.js
index e1571862ed..c3bb660e8c 100644
--- a/packages/svelte/src/internal/client/context.js
+++ b/packages/svelte/src/internal/client/context.js
@@ -72,17 +72,17 @@ export function set_dev_current_component_function(fn) {
 }
 
 /**
- * Returns a `[get, set]` pair of functions for working with context in a type-safe way.
+ * Returns a `[get, set, has]` triplet of functions for working with context in a type-safe way.
  *
  * `get` will throw an error if `set` has not yet been called in the current component or any of
  * its ancestors.
  *
  * @template T
- * @returns {[() => T, (context: T) => T]}
+ * @returns {[() => T, (context: T) => T, () => boolean]}
  * @since 5.40.0
  */
 export function createContext() {
-	return /** @type {[() => T, (context: T) => T]} */ (
+	return /** @type {[() => T, (context: T) => T, () => boolean]} */ (
 		create_context(getContext, setContext, hasContext)
 	);
 }
diff --git a/packages/svelte/src/internal/server/context.js b/packages/svelte/src/internal/server/context.js
index de11c11282..b204c4c138 100644
--- a/packages/svelte/src/internal/server/context.js
+++ b/packages/svelte/src/internal/server/context.js
@@ -12,11 +12,11 @@ export function set_ssr_context(v) {
 
 /**
  * @template T
- * @returns {[() => T, (context: T) => T]}
+ * @returns {[() => T, (context: T) => T, () => boolean]}
  * @since 5.40.0
  */
 export function createContext() {
-	return /** @type {[() => T, (context: T) => T]} */ (
+	return /** @type {[() => T, (context: T) => T, () => boolean]} */ (
 		create_context(getContext, setContext, hasContext)
 	);
 }
diff --git a/packages/svelte/src/internal/shared/context.js b/packages/svelte/src/internal/shared/context.js
index 943e15e415..005c009101 100644
--- a/packages/svelte/src/internal/shared/context.js
+++ b/packages/svelte/src/internal/shared/context.js
@@ -5,7 +5,7 @@ import { lifecycle_outside_component, missing_context } from './errors.js';
  * @param {(key: object) => T} get_context
  * @param {(key: object, context: T) => T} set_context
  * @param {(key: object) => boolean} has_context
- * @returns {[() => T, (context: T) => T]}
+ * @returns {[() => T, (context: T) => T, () => boolean]}
  */
 export function create_context(get_context, set_context, has_context) {
 	const key = {};
@@ -18,7 +18,8 @@ export function create_context(get_context, set_context, has_context) {
 
 			return get_context(key);
 		},
-		(context) => set_context(key, context)
+		(context) => set_context(key, context),
+		() => has_context(key)
 	];
 }
 
diff --git a/packages/svelte/tests/runtime-runes/samples/create-context-programmatic/Child.svelte b/packages/svelte/tests/runtime-runes/samples/create-context-programmatic/Child.svelte
index 3e39d5043e..0255132ad6 100644
--- a/packages/svelte/tests/runtime-runes/samples/create-context-programmatic/Child.svelte
+++ b/packages/svelte/tests/runtime-runes/samples/create-context-programmatic/Child.svelte
@@ -1,7 +1,13 @@
 <script>
-	import { get } from './main.svelte';
+	import { get, has, has_unset } from './main.svelte';
 
 	const message = get();
 </script>
 
 <h1>{message}</h1>
+{#if has()}
+	<h2>it's me</h2>
+{/if}
+{#if !has_unset()}
+	<h2>or not</h2>
+{/if}
diff --git a/packages/svelte/tests/runtime-runes/samples/create-context-programmatic/_config.js b/packages/svelte/tests/runtime-runes/samples/create-context-programmatic/_config.js
index f4374c8759..c2eeca0de8 100644
--- a/packages/svelte/tests/runtime-runes/samples/create-context-programmatic/_config.js
+++ b/packages/svelte/tests/runtime-runes/samples/create-context-programmatic/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	ssrHtml: `<div></div>`,
-	html: `<div><h1>hello</h1></div>`,
+	html: `<div><h1>hello</h1><h2>it's me</h2><h2>or not</h2></div>`,
 
 	test() {}
 });
diff --git a/packages/svelte/tests/runtime-runes/samples/create-context-programmatic/main.svelte b/packages/svelte/tests/runtime-runes/samples/create-context-programmatic/main.svelte
index 3c42dbf180..8f4fb67d23 100644
--- a/packages/svelte/tests/runtime-runes/samples/create-context-programmatic/main.svelte
+++ b/packages/svelte/tests/runtime-runes/samples/create-context-programmatic/main.svelte
@@ -3,9 +3,11 @@
 	import Child from './Child.svelte';
 
 	/** @type {ReturnType<typeof createContext<string>>} */
-	const [get, set] = createContext();
+	const [get, set, has] = createContext();
+	/** @type {ReturnType<typeof createContext<string>>} */
+	const [, , has_unset] = createContext();
 
-	export { get };
+	export { get, has, has_unset };
 
 	function Wrapper(Component) {
 		return (...args) => {
@@ -15,6 +17,8 @@
 	}
 </script>
 
-<div {@attach (target) => {
-	mount(Wrapper(Child), { target });
-}}></div>
+<div
+	{@attach (target) => {
+		mount(Wrapper(Child), { target });
+	}}
+></div>
diff --git a/packages/svelte/tests/runtime-runes/samples/create-context/Child.svelte b/packages/svelte/tests/runtime-runes/samples/create-context/Child.svelte
index 3e39d5043e..0255132ad6 100644
--- a/packages/svelte/tests/runtime-runes/samples/create-context/Child.svelte
+++ b/packages/svelte/tests/runtime-runes/samples/create-context/Child.svelte
@@ -1,7 +1,13 @@
 <script>
-	import { get } from './main.svelte';
+	import { get, has, has_unset } from './main.svelte';
 
 	const message = get();
 </script>
 
 <h1>{message}</h1>
+{#if has()}
+	<h2>it's me</h2>
+{/if}
+{#if !has_unset()}
+	<h2>or not</h2>
+{/if}
diff --git a/packages/svelte/tests/runtime-runes/samples/create-context/_config.js b/packages/svelte/tests/runtime-runes/samples/create-context/_config.js
index 4ae28e68bd..fa782095de 100644
--- a/packages/svelte/tests/runtime-runes/samples/create-context/_config.js
+++ b/packages/svelte/tests/runtime-runes/samples/create-context/_config.js
@@ -1,5 +1,5 @@
 import { test } from '../../test';
 
 export default test({
-	html: `<h1>hello</h1>`
+	html: `<h1>hello</h1><h2>it's me</h2><h2>or not</h2>`
 });
diff --git a/packages/svelte/tests/runtime-runes/samples/create-context/main.svelte b/packages/svelte/tests/runtime-runes/samples/create-context/main.svelte
index 8d3c50ba55..35093f4c4e 100644
--- a/packages/svelte/tests/runtime-runes/samples/create-context/main.svelte
+++ b/packages/svelte/tests/runtime-runes/samples/create-context/main.svelte
@@ -2,9 +2,11 @@
 	import { createContext } from 'svelte';
 
 	/** @type {ReturnType<typeof createContext<string>>} */
-	const [get, set] = createContext();
+	const [get, set, has] = createContext();
+	/** @type {ReturnType<typeof createContext<string>>} */
+	const [, , has_unset] = createContext();
 
-	export { get };
+	export { get, has, has_unset };
 </script>
 
 <script>
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index 9e69796691..661b840354 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -492,14 +492,14 @@ declare module 'svelte' {
 	 */
 	export function fork(fn: () => void): Fork;
 	/**
-	 * Returns a `[get, set]` pair of functions for working with context in a type-safe way.
+	 * Returns a `[get, set, has]` triplet of functions for working with context in a type-safe way.
 	 *
 	 * `get` will throw an error if `set` has not yet been called in the current component or any of
 	 * its ancestors.
 	 *
 	 * @since 5.40.0
 	 */
-	export function createContext<T>(): [() => T, (context: T) => T];
+	export function createContext<T>(): [() => T, (context: T) => T, () => boolean];
 	/**
 	 * Retrieves the context set with the specified `key` in the current component or any of its
 	 * ancestors. If multiple components set the same key, the value from the closest one is returned.

From 6374a2a0db1cc2130e9ee69a233ce6d4c7334f82 Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Fri, 28 Aug 2026 04:52:34 -0400
Subject: [PATCH 210/222] chore: move `@types/trusted-types` to devDependencies
 (#18730)

Only referenced by a JSDoc `@import` in
`src/internal/client/dom/blocks/html.js`; nothing in the published
`types/index.d.ts` uses it, so consumers do not need it installed.
---
 .changeset/quiet-types-move.md | 5 +++++
 packages/svelte/package.json   | 2 +-
 pnpm-lock.yaml                 | 6 +++---
 3 files changed, 9 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/quiet-types-move.md

diff --git a/.changeset/quiet-types-move.md b/.changeset/quiet-types-move.md
new file mode 100644
index 0000000000..5c7180a01f
--- /dev/null
+++ b/.changeset/quiet-types-move.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+chore: move `@types/trusted-types` to devDependencies
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 1f85001520..37489ac109 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -159,6 +159,7 @@
     "@rollup/plugin-virtual": "^3.0.2",
     "@types/aria-query": "^5.0.4",
     "@types/node": "^20.11.5",
+    "@types/trusted-types": "^2.0.7",
     "baseline-browser-mapping": "^2.10.32",
     "dts-buddy": "^0.5.5",
     "esbuild": "^0.28.1",
@@ -174,7 +175,6 @@
     "@jridgewell/sourcemap-codec": "^1.5.0",
     "@sveltejs/acorn-typescript": "^1.0.10",
     "@types/estree": "^1.0.5",
-    "@types/trusted-types": "^2.0.7",
     "acorn": "^8.12.1",
     "aria-query": "5.3.1",
     "axobject-query": "^4.1.0",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 9224650e7d..c51620fff5 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -80,9 +80,6 @@ importers:
       '@types/estree':
         specifier: ^1.0.5
         version: 1.0.8
-      '@types/trusted-types':
-        specifier: ^2.0.7
-        version: 2.0.7
       acorn:
         specifier: ^8.12.1
         version: 8.16.0
@@ -141,6 +138,9 @@ importers:
       '@types/node':
         specifier: ^20.11.5
         version: 20.19.17
+      '@types/trusted-types':
+        specifier: ^2.0.7
+        version: 2.0.7
       baseline-browser-mapping:
         specifier: ^2.10.32
         version: 2.10.32

From 7bc0a70fe64dbb3fa3848b741963f31d1e10a8dc Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Sat, 29 Aug 2026 01:26:56 +0200
Subject: [PATCH 211/222] Version Packages (#18682)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.


# Releases
## svelte@5.57.0

### Minor Changes

- feat: export `RenderOutput`, `SyncRenderOutput`, `Csp` and
`Sha256Source` from `svelte/server`
([#18648](https://github.com/sveltejs/svelte/pull/18648))

- feat: add `has` function to `createContext`
([#18472](https://github.com/sveltejs/svelte/pull/18472))

- feat: support `defaultValue` on `<select>`
([#18591](https://github.com/sveltejs/svelte/pull/18591))

- feat: add getOrInsert/getOrInsertComputed to SvelteMap
([#18728](https://github.com/sveltejs/svelte/pull/18728))

### Patch Changes

- fix: block template store subscriptions on the promise that assigns
the store ([#18582](https://github.com/sveltejs/svelte/pull/18582))

- fix: route $derived teardown errors through invoke_error_boundary
([#18486](https://github.com/sveltejs/svelte/pull/18486))

- fix: track SvelteDate snapshots in reactions
([#18700](https://github.com/sveltejs/svelte/pull/18700))

- fix: remove `<svelte:head>` anchors on unmount
([#18697](https://github.com/sveltejs/svelte/pull/18697))

- fix: warn on undeclared shorthand event handlers on `<svelte:window>`,
`<svelte:document>` and `<svelte:body>`
([#18480](https://github.com/sveltejs/svelte/pull/18480))

- perf: reuse the cached value in the `<option>`/`<select>` value guard
([#18713](https://github.com/sveltejs/svelte/pull/18713))

- fix: prevent malformed AST output for `<select>` with static `value`
attribute ([#18449](https://github.com/sveltejs/svelte/pull/18449))

- fix: apply ownership mutation ignores to binding assignments
([#18718](https://github.com/sveltejs/svelte/pull/18718))

- fix: prevent onoutroend from firing twice when compilerOptions.hmr is
true ([#18655](https://github.com/sveltejs/svelte/pull/18655))

- fix: preserve whitespace after inline elements when printing
([#18685](https://github.com/sveltejs/svelte/pull/18685))

- perf: fold SSR block-open markers into the branch's first push
([#18712](https://github.com/sveltejs/svelte/pull/18712))

- fix: run `onDestroy` callbacks when a server render throws
([#18585](https://github.com/sveltejs/svelte/pull/18585))

- fix: report `derived_invalid_export` for `export let x =
$derived(...)` in runes mode
([#18692](https://github.com/sveltejs/svelte/pull/18692))

- fix: never apply class hash to elements inside `<svelte:head>`
([#18160](https://github.com/sveltejs/svelte/pull/18160))

- fix: keep `defaultChecked` on hydrated radio inputs with spread
attributes ([#18701](https://github.com/sveltejs/svelte/pull/18701))

- fix: accept `onfocusin`/`onfocusout` in
`a11y_mouse_events_have_key_events`
([#18689](https://github.com/sveltejs/svelte/pull/18689))

- perf: O(n²)→O(n) Map lookups for legacy `$:` reactive statement
ordering ([#18602](https://github.com/sveltejs/svelte/pull/18602))

- fix: distinct memoizer on style/class directives
([#18466](https://github.com/sveltejs/svelte/pull/18466))

- fix: measure nested transitions before applying their starting styles
([#18647](https://github.com/sveltejs/svelte/pull/18647))

- fix: don't turn component instances stored in `$state` into state
proxies ([#18646](https://github.com/sveltejs/svelte/pull/18646))

- perf: emit `$.only_child` for elements with a single child
([#18717](https://github.com/sveltejs/svelte/pull/18717))

- fix: omit `bind:focused` from SSR output (it has no HTML attribute)
([#18724](https://github.com/sveltejs/svelte/pull/18724))

- fix: more robust rendering of Svelte custom element slots
([#18710](https://github.com/sveltejs/svelte/pull/18710))

- perf: optimize simple object destructuring in `@const` tags
([#18390](https://github.com/sveltejs/svelte/pull/18390))

- fix: properly apply static textarea value attribute during CSR
([#18727](https://github.com/sveltejs/svelte/pull/18727))

- fix: end a restored reaction context at the end of its synchronous
segment ([#18694](https://github.com/sveltejs/svelte/pull/18694))

- fix: keep the dependencies of a reaction that throws, so deriveds it
read are neither leaked nor stuck in their error
([#18703](https://github.com/sveltejs/svelte/pull/18703))

- fix: don't resurrect outroing elements when an ancestor block is
paused and resumed
([#18431](https://github.com/sveltejs/svelte/pull/18431))

- perf: use `$.comment()` for single-comment templates
([#18714](https://github.com/sveltejs/svelte/pull/18714))

- chore: move `@types/trusted-types` to devDependencies
([#18730](https://github.com/sveltejs/svelte/pull/18730))

- perf: store setters cache as `Set` instead of `Array`
([#18251](https://github.com/sveltejs/svelte/pull/18251))

- fix: transform derived assignments and select function bindings
correctly during server-side rendering
([#18669](https://github.com/sveltejs/svelte/pull/18669))

- fix: keep boolean attributes with an empty string value when rendering
attribute objects on the server
([#18721](https://github.com/sveltejs/svelte/pull/18721))

- fix: sync `SvelteURL` port signal when the protocol setter clears the
port ([#18705](https://github.com/sveltejs/svelte/pull/18705))

- fix: block declaration tags and `{@const}` on async values read inside
closures ([#18533](https://github.com/sveltejs/svelte/pull/18533))

- fix: avoid css tree-shaking for exported Snippet
([#18540](https://github.com/sveltejs/svelte/pull/18540))

- perf: treat `<img loading>` as a static element again
([#18711](https://github.com/sveltejs/svelte/pull/18711))

- fix: prevent `selectedcontent` mutation from changing the selected
option ([#18495](https://github.com/sveltejs/svelte/pull/18495))

- fix: avoid `NaN` keyframe values in `slide` transition for elements
without a layout box
([#18430](https://github.com/sveltejs/svelte/pull/18430))

- fix: preserve line feed character references in attribute values
([#18691](https://github.com/sveltejs/svelte/pull/18691))

- fix: decode uppercase-`X` hex numeric character references (`&#X...;`)
([#18708](https://github.com/sveltejs/svelte/pull/18708))

- chore: clarify when `$effect.pre` runs relative to DOM updates
([#18534](https://github.com/sveltejs/svelte/pull/18534))

- fix: scope SSR boundary failed snippets to their boundary
([#18593](https://github.com/sveltejs/svelte/pull/18593))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/async-store-sub-blocker.md         |   5 -
 .changeset/boundary-teardown-error-routing.md |   5 -
 .changeset/calm-dates-track.md                |   5 -
 .changeset/clean-head-anchors.md              |   5 -
 .changeset/cool-spoons-tap.md                 |   5 -
 .changeset/eighty-moons-happen.md             |   5 -
 .changeset/every-rabbits-rule.md              |   5 -
 .changeset/fix-binding-ownership-ignore.md    |   5 -
 .changeset/fix-hmr-onoutroend-double-fire.md  |   5 -
 .changeset/gentle-spaces-print.md             |   5 -
 .changeset/gold-moons-shave.md                |   5 -
 .changeset/great-hoops-tickle.md              |   5 -
 .changeset/heavy-pumas-report.md              |   5 -
 .changeset/hungry-plums-roll.md               |   5 -
 .changeset/keep-radio-default-checked.md      |   5 -
 .changeset/large-schools-smell.md             |   5 -
 .changeset/legacy-reactive-map-lookups.md     |   5 -
 .changeset/lemon-bikes-marry.md               |   5 -
 .changeset/moody-lamps-slide.md               |   5 -
 .changeset/olive-crabs-refuse.md              |   5 -
 .changeset/olive-jars-repeat.md               |   5 -
 .changeset/olive-pugs-shake.md                |   5 -
 .changeset/omit-bind-focused-ssr.md           |   5 -
 .changeset/open-parents-stare.md              |   5 -
 .changeset/optimize-const-tag.md              |   5 -
 .changeset/polite-zoos-melt.md                |   5 -
 .changeset/quiet-context-segment.md           |   5 -
 .changeset/quiet-deriveds-unwind.md           |   5 -
 .changeset/quiet-falcons-search.md            |   5 -
 .changeset/quiet-swans-invent.md              |   5 -
 .changeset/quiet-types-move.md                |   5 -
 .changeset/setters-cache-set.md               |   5 -
 .changeset/short-feet-admire.md               |   5 -
 .changeset/slow-dots-smile.md                 |   5 -
 .changeset/ssr-empty-boolean-attribute.md     |   5 -
 .changeset/svelte-url-protocol-port.md        |   5 -
 .changeset/tall-hounds-tap.md                 |   5 -
 .changeset/tasty-years-hammer.md              |   5 -
 .changeset/thick-plums-wave.md                |   5 -
 .changeset/three-peas-smoke.md                |   5 -
 .changeset/tidy-owls-repeat.md                |   5 -
 .changeset/tidy-pandas-refuse.md              |   5 -
 .changeset/tough-pandas-shout.md              |   5 -
 .changeset/tricky-donkeys-clap.md             |   5 -
 .changeset/uppercase-hex-entities.md          |   5 -
 .changeset/witty-donuts-explain.md            |   5 -
 .changeset/young-papers-hide.md               |   5 -
 packages/svelte/CHANGELOG.md                  | 100 ++++++++++++++++++
 packages/svelte/package.json                  |   2 +-
 packages/svelte/src/version.js                |   2 +-
 50 files changed, 102 insertions(+), 237 deletions(-)
 delete mode 100644 .changeset/async-store-sub-blocker.md
 delete mode 100644 .changeset/boundary-teardown-error-routing.md
 delete mode 100644 .changeset/calm-dates-track.md
 delete mode 100644 .changeset/clean-head-anchors.md
 delete mode 100644 .changeset/cool-spoons-tap.md
 delete mode 100644 .changeset/eighty-moons-happen.md
 delete mode 100644 .changeset/every-rabbits-rule.md
 delete mode 100644 .changeset/fix-binding-ownership-ignore.md
 delete mode 100644 .changeset/fix-hmr-onoutroend-double-fire.md
 delete mode 100644 .changeset/gentle-spaces-print.md
 delete mode 100644 .changeset/gold-moons-shave.md
 delete mode 100644 .changeset/great-hoops-tickle.md
 delete mode 100644 .changeset/heavy-pumas-report.md
 delete mode 100644 .changeset/hungry-plums-roll.md
 delete mode 100644 .changeset/keep-radio-default-checked.md
 delete mode 100644 .changeset/large-schools-smell.md
 delete mode 100644 .changeset/legacy-reactive-map-lookups.md
 delete mode 100644 .changeset/lemon-bikes-marry.md
 delete mode 100644 .changeset/moody-lamps-slide.md
 delete mode 100644 .changeset/olive-crabs-refuse.md
 delete mode 100644 .changeset/olive-jars-repeat.md
 delete mode 100644 .changeset/olive-pugs-shake.md
 delete mode 100644 .changeset/omit-bind-focused-ssr.md
 delete mode 100644 .changeset/open-parents-stare.md
 delete mode 100644 .changeset/optimize-const-tag.md
 delete mode 100644 .changeset/polite-zoos-melt.md
 delete mode 100644 .changeset/quiet-context-segment.md
 delete mode 100644 .changeset/quiet-deriveds-unwind.md
 delete mode 100644 .changeset/quiet-falcons-search.md
 delete mode 100644 .changeset/quiet-swans-invent.md
 delete mode 100644 .changeset/quiet-types-move.md
 delete mode 100644 .changeset/setters-cache-set.md
 delete mode 100644 .changeset/short-feet-admire.md
 delete mode 100644 .changeset/slow-dots-smile.md
 delete mode 100644 .changeset/ssr-empty-boolean-attribute.md
 delete mode 100644 .changeset/svelte-url-protocol-port.md
 delete mode 100644 .changeset/tall-hounds-tap.md
 delete mode 100644 .changeset/tasty-years-hammer.md
 delete mode 100644 .changeset/thick-plums-wave.md
 delete mode 100644 .changeset/three-peas-smoke.md
 delete mode 100644 .changeset/tidy-owls-repeat.md
 delete mode 100644 .changeset/tidy-pandas-refuse.md
 delete mode 100644 .changeset/tough-pandas-shout.md
 delete mode 100644 .changeset/tricky-donkeys-clap.md
 delete mode 100644 .changeset/uppercase-hex-entities.md
 delete mode 100644 .changeset/witty-donuts-explain.md
 delete mode 100644 .changeset/young-papers-hide.md

diff --git a/.changeset/async-store-sub-blocker.md b/.changeset/async-store-sub-blocker.md
deleted file mode 100644
index 0222dac846..0000000000
--- a/.changeset/async-store-sub-blocker.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: block template store subscriptions on the promise that assigns the store
diff --git a/.changeset/boundary-teardown-error-routing.md b/.changeset/boundary-teardown-error-routing.md
deleted file mode 100644
index 0b2249bf22..0000000000
--- a/.changeset/boundary-teardown-error-routing.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: route $derived teardown errors through invoke_error_boundary
diff --git a/.changeset/calm-dates-track.md b/.changeset/calm-dates-track.md
deleted file mode 100644
index e7275ae556..0000000000
--- a/.changeset/calm-dates-track.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: track SvelteDate snapshots in reactions
diff --git a/.changeset/clean-head-anchors.md b/.changeset/clean-head-anchors.md
deleted file mode 100644
index d58283f502..0000000000
--- a/.changeset/clean-head-anchors.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: remove `<svelte:head>` anchors on unmount
diff --git a/.changeset/cool-spoons-tap.md b/.changeset/cool-spoons-tap.md
deleted file mode 100644
index 461db03a81..0000000000
--- a/.changeset/cool-spoons-tap.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: warn on undeclared shorthand event handlers on `<svelte:window>`, `<svelte:document>` and `<svelte:body>`
diff --git a/.changeset/eighty-moons-happen.md b/.changeset/eighty-moons-happen.md
deleted file mode 100644
index 94fb3d313d..0000000000
--- a/.changeset/eighty-moons-happen.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-perf: reuse the cached value in the `<option>`/`<select>` value guard
diff --git a/.changeset/every-rabbits-rule.md b/.changeset/every-rabbits-rule.md
deleted file mode 100644
index e78df191a5..0000000000
--- a/.changeset/every-rabbits-rule.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: prevent malformed AST output for `<select>` with static `value` attribute
diff --git a/.changeset/fix-binding-ownership-ignore.md b/.changeset/fix-binding-ownership-ignore.md
deleted file mode 100644
index 13c9c797e3..0000000000
--- a/.changeset/fix-binding-ownership-ignore.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: apply ownership mutation ignores to binding assignments
diff --git a/.changeset/fix-hmr-onoutroend-double-fire.md b/.changeset/fix-hmr-onoutroend-double-fire.md
deleted file mode 100644
index 0eafbfa731..0000000000
--- a/.changeset/fix-hmr-onoutroend-double-fire.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: prevent onoutroend from firing twice when compilerOptions.hmr is true
diff --git a/.changeset/gentle-spaces-print.md b/.changeset/gentle-spaces-print.md
deleted file mode 100644
index 70b337fcd7..0000000000
--- a/.changeset/gentle-spaces-print.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: preserve whitespace after inline elements when printing
diff --git a/.changeset/gold-moons-shave.md b/.changeset/gold-moons-shave.md
deleted file mode 100644
index 9ee98321b7..0000000000
--- a/.changeset/gold-moons-shave.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-perf: fold SSR block-open markers into the branch's first push
diff --git a/.changeset/great-hoops-tickle.md b/.changeset/great-hoops-tickle.md
deleted file mode 100644
index 94b32588f1..0000000000
--- a/.changeset/great-hoops-tickle.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: run `onDestroy` callbacks when a server render throws
diff --git a/.changeset/heavy-pumas-report.md b/.changeset/heavy-pumas-report.md
deleted file mode 100644
index 71a9422828..0000000000
--- a/.changeset/heavy-pumas-report.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: report `derived_invalid_export` for `export let x = $derived(...)` in runes mode
diff --git a/.changeset/hungry-plums-roll.md b/.changeset/hungry-plums-roll.md
deleted file mode 100644
index b5e3688eb5..0000000000
--- a/.changeset/hungry-plums-roll.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: never apply class hash to elements inside `<svelte:head>`
diff --git a/.changeset/keep-radio-default-checked.md b/.changeset/keep-radio-default-checked.md
deleted file mode 100644
index b3b32afda6..0000000000
--- a/.changeset/keep-radio-default-checked.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: keep `defaultChecked` on hydrated radio inputs with spread attributes
diff --git a/.changeset/large-schools-smell.md b/.changeset/large-schools-smell.md
deleted file mode 100644
index 61ef571f02..0000000000
--- a/.changeset/large-schools-smell.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: accept `onfocusin`/`onfocusout` in `a11y_mouse_events_have_key_events`
diff --git a/.changeset/legacy-reactive-map-lookups.md b/.changeset/legacy-reactive-map-lookups.md
deleted file mode 100644
index ec6f4fbf9d..0000000000
--- a/.changeset/legacy-reactive-map-lookups.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-perf: O(n²)→O(n) Map lookups for legacy `$:` reactive statement ordering
diff --git a/.changeset/lemon-bikes-marry.md b/.changeset/lemon-bikes-marry.md
deleted file mode 100644
index 6b1c431a30..0000000000
--- a/.changeset/lemon-bikes-marry.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: distinct memoizer on style/class directives
diff --git a/.changeset/moody-lamps-slide.md b/.changeset/moody-lamps-slide.md
deleted file mode 100644
index 5832f12e42..0000000000
--- a/.changeset/moody-lamps-slide.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: measure nested transitions before applying their starting styles
diff --git a/.changeset/olive-crabs-refuse.md b/.changeset/olive-crabs-refuse.md
deleted file mode 100644
index a928ae7f19..0000000000
--- a/.changeset/olive-crabs-refuse.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: don't turn component instances stored in `$state` into state proxies
diff --git a/.changeset/olive-jars-repeat.md b/.changeset/olive-jars-repeat.md
deleted file mode 100644
index 815b5adf71..0000000000
--- a/.changeset/olive-jars-repeat.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': minor
----
-
-feat: export `RenderOutput`, `SyncRenderOutput`, `Csp` and `Sha256Source` from `svelte/server`
diff --git a/.changeset/olive-pugs-shake.md b/.changeset/olive-pugs-shake.md
deleted file mode 100644
index abd0db2152..0000000000
--- a/.changeset/olive-pugs-shake.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-perf: emit `$.only_child` for elements with a single child
diff --git a/.changeset/omit-bind-focused-ssr.md b/.changeset/omit-bind-focused-ssr.md
deleted file mode 100644
index 80200808aa..0000000000
--- a/.changeset/omit-bind-focused-ssr.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: omit `bind:focused` from SSR output (it has no HTML attribute)
diff --git a/.changeset/open-parents-stare.md b/.changeset/open-parents-stare.md
deleted file mode 100644
index cb94267ea0..0000000000
--- a/.changeset/open-parents-stare.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: more robust rendering of Svelte custom element slots
diff --git a/.changeset/optimize-const-tag.md b/.changeset/optimize-const-tag.md
deleted file mode 100644
index 90c6a6b5d2..0000000000
--- a/.changeset/optimize-const-tag.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-"svelte": patch
----
-
-perf: optimize simple object destructuring in `@const` tags
diff --git a/.changeset/polite-zoos-melt.md b/.changeset/polite-zoos-melt.md
deleted file mode 100644
index cfff0e82e4..0000000000
--- a/.changeset/polite-zoos-melt.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: properly apply static textarea value attribute during CSR
diff --git a/.changeset/quiet-context-segment.md b/.changeset/quiet-context-segment.md
deleted file mode 100644
index 7af36f8ed3..0000000000
--- a/.changeset/quiet-context-segment.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: end a restored reaction context at the end of its synchronous segment
diff --git a/.changeset/quiet-deriveds-unwind.md b/.changeset/quiet-deriveds-unwind.md
deleted file mode 100644
index 8036bdb781..0000000000
--- a/.changeset/quiet-deriveds-unwind.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: keep the dependencies of a reaction that throws, so deriveds it read are neither leaked nor stuck in their error
diff --git a/.changeset/quiet-falcons-search.md b/.changeset/quiet-falcons-search.md
deleted file mode 100644
index 8c5c4dedca..0000000000
--- a/.changeset/quiet-falcons-search.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: don't resurrect outroing elements when an ancestor block is paused and resumed
diff --git a/.changeset/quiet-swans-invent.md b/.changeset/quiet-swans-invent.md
deleted file mode 100644
index 3b35a933d5..0000000000
--- a/.changeset/quiet-swans-invent.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-perf: use `$.comment()` for single-comment templates
diff --git a/.changeset/quiet-types-move.md b/.changeset/quiet-types-move.md
deleted file mode 100644
index 5c7180a01f..0000000000
--- a/.changeset/quiet-types-move.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-chore: move `@types/trusted-types` to devDependencies
diff --git a/.changeset/setters-cache-set.md b/.changeset/setters-cache-set.md
deleted file mode 100644
index 2013446bc5..0000000000
--- a/.changeset/setters-cache-set.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-perf: store setters cache as `Set` instead of `Array`
diff --git a/.changeset/short-feet-admire.md b/.changeset/short-feet-admire.md
deleted file mode 100644
index fdf56477c9..0000000000
--- a/.changeset/short-feet-admire.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': minor
----
-
-feat: add `has` function to `createContext`
diff --git a/.changeset/slow-dots-smile.md b/.changeset/slow-dots-smile.md
deleted file mode 100644
index 18d2517b6c..0000000000
--- a/.changeset/slow-dots-smile.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: transform derived assignments and select function bindings correctly during server-side rendering
diff --git a/.changeset/ssr-empty-boolean-attribute.md b/.changeset/ssr-empty-boolean-attribute.md
deleted file mode 100644
index dbf5465014..0000000000
--- a/.changeset/ssr-empty-boolean-attribute.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: keep boolean attributes with an empty string value when rendering attribute objects on the server
diff --git a/.changeset/svelte-url-protocol-port.md b/.changeset/svelte-url-protocol-port.md
deleted file mode 100644
index 2c37fce4ab..0000000000
--- a/.changeset/svelte-url-protocol-port.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: sync `SvelteURL` port signal when the protocol setter clears the port
diff --git a/.changeset/tall-hounds-tap.md b/.changeset/tall-hounds-tap.md
deleted file mode 100644
index 3a9f7d79cb..0000000000
--- a/.changeset/tall-hounds-tap.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': minor
----
-
-feat: support `defaultValue` on `<select>`
diff --git a/.changeset/tasty-years-hammer.md b/.changeset/tasty-years-hammer.md
deleted file mode 100644
index 42b559ac9f..0000000000
--- a/.changeset/tasty-years-hammer.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': minor
----
-
-feat: add getOrInsert/getOrInsertComputed to SvelteMap
diff --git a/.changeset/thick-plums-wave.md b/.changeset/thick-plums-wave.md
deleted file mode 100644
index d8b454bb90..0000000000
--- a/.changeset/thick-plums-wave.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: block declaration tags and `{@const}` on async values read inside closures
diff --git a/.changeset/three-peas-smoke.md b/.changeset/three-peas-smoke.md
deleted file mode 100644
index 9a151c0046..0000000000
--- a/.changeset/three-peas-smoke.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: avoid css tree-shaking for exported Snippet
diff --git a/.changeset/tidy-owls-repeat.md b/.changeset/tidy-owls-repeat.md
deleted file mode 100644
index 2ef02e2051..0000000000
--- a/.changeset/tidy-owls-repeat.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-perf: treat `<img loading>` as a static element again
diff --git a/.changeset/tidy-pandas-refuse.md b/.changeset/tidy-pandas-refuse.md
deleted file mode 100644
index 7034a3e267..0000000000
--- a/.changeset/tidy-pandas-refuse.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: prevent `selectedcontent` mutation from changing the selected option
diff --git a/.changeset/tough-pandas-shout.md b/.changeset/tough-pandas-shout.md
deleted file mode 100644
index b0f6ea64fd..0000000000
--- a/.changeset/tough-pandas-shout.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: avoid `NaN` keyframe values in `slide` transition for elements without a layout box
diff --git a/.changeset/tricky-donkeys-clap.md b/.changeset/tricky-donkeys-clap.md
deleted file mode 100644
index b363b4ff57..0000000000
--- a/.changeset/tricky-donkeys-clap.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: preserve line feed character references in attribute values
diff --git a/.changeset/uppercase-hex-entities.md b/.changeset/uppercase-hex-entities.md
deleted file mode 100644
index e6e13d5df5..0000000000
--- a/.changeset/uppercase-hex-entities.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: decode uppercase-`X` hex numeric character references (`&#X...;`)
diff --git a/.changeset/witty-donuts-explain.md b/.changeset/witty-donuts-explain.md
deleted file mode 100644
index 6ee8f66da6..0000000000
--- a/.changeset/witty-donuts-explain.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-chore: clarify when `$effect.pre` runs relative to DOM updates
diff --git a/.changeset/young-papers-hide.md b/.changeset/young-papers-hide.md
deleted file mode 100644
index 7df1f114b9..0000000000
--- a/.changeset/young-papers-hide.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: scope SSR boundary failed snippets to their boundary
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index e66b3db109..e88e078486 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,105 @@
 # svelte
 
+## 5.57.0
+
+### Minor Changes
+
+- feat: export `RenderOutput`, `SyncRenderOutput`, `Csp` and `Sha256Source` from `svelte/server` ([#18648](https://github.com/sveltejs/svelte/pull/18648))
+
+- feat: add `has` function to `createContext` ([#18472](https://github.com/sveltejs/svelte/pull/18472))
+
+- feat: support `defaultValue` on `<select>` ([#18591](https://github.com/sveltejs/svelte/pull/18591))
+
+- feat: add getOrInsert/getOrInsertComputed to SvelteMap ([#18728](https://github.com/sveltejs/svelte/pull/18728))
+
+### Patch Changes
+
+- fix: block template store subscriptions on the promise that assigns the store ([#18582](https://github.com/sveltejs/svelte/pull/18582))
+
+- fix: route $derived teardown errors through invoke_error_boundary ([#18486](https://github.com/sveltejs/svelte/pull/18486))
+
+- fix: track SvelteDate snapshots in reactions ([#18700](https://github.com/sveltejs/svelte/pull/18700))
+
+- fix: remove `<svelte:head>` anchors on unmount ([#18697](https://github.com/sveltejs/svelte/pull/18697))
+
+- fix: warn on undeclared shorthand event handlers on `<svelte:window>`, `<svelte:document>` and `<svelte:body>` ([#18480](https://github.com/sveltejs/svelte/pull/18480))
+
+- perf: reuse the cached value in the `<option>`/`<select>` value guard ([#18713](https://github.com/sveltejs/svelte/pull/18713))
+
+- fix: prevent malformed AST output for `<select>` with static `value` attribute ([#18449](https://github.com/sveltejs/svelte/pull/18449))
+
+- fix: apply ownership mutation ignores to binding assignments ([#18718](https://github.com/sveltejs/svelte/pull/18718))
+
+- fix: prevent onoutroend from firing twice when compilerOptions.hmr is true ([#18655](https://github.com/sveltejs/svelte/pull/18655))
+
+- fix: preserve whitespace after inline elements when printing ([#18685](https://github.com/sveltejs/svelte/pull/18685))
+
+- perf: fold SSR block-open markers into the branch's first push ([#18712](https://github.com/sveltejs/svelte/pull/18712))
+
+- fix: run `onDestroy` callbacks when a server render throws ([#18585](https://github.com/sveltejs/svelte/pull/18585))
+
+- fix: report `derived_invalid_export` for `export let x = $derived(...)` in runes mode ([#18692](https://github.com/sveltejs/svelte/pull/18692))
+
+- fix: never apply class hash to elements inside `<svelte:head>` ([#18160](https://github.com/sveltejs/svelte/pull/18160))
+
+- fix: keep `defaultChecked` on hydrated radio inputs with spread attributes ([#18701](https://github.com/sveltejs/svelte/pull/18701))
+
+- fix: accept `onfocusin`/`onfocusout` in `a11y_mouse_events_have_key_events` ([#18689](https://github.com/sveltejs/svelte/pull/18689))
+
+- perf: O(n²)→O(n) Map lookups for legacy `$:` reactive statement ordering ([#18602](https://github.com/sveltejs/svelte/pull/18602))
+
+- fix: distinct memoizer on style/class directives ([#18466](https://github.com/sveltejs/svelte/pull/18466))
+
+- fix: measure nested transitions before applying their starting styles ([#18647](https://github.com/sveltejs/svelte/pull/18647))
+
+- fix: don't turn component instances stored in `$state` into state proxies ([#18646](https://github.com/sveltejs/svelte/pull/18646))
+
+- perf: emit `$.only_child` for elements with a single child ([#18717](https://github.com/sveltejs/svelte/pull/18717))
+
+- fix: omit `bind:focused` from SSR output (it has no HTML attribute) ([#18724](https://github.com/sveltejs/svelte/pull/18724))
+
+- fix: more robust rendering of Svelte custom element slots ([#18710](https://github.com/sveltejs/svelte/pull/18710))
+
+- perf: optimize simple object destructuring in `@const` tags ([#18390](https://github.com/sveltejs/svelte/pull/18390))
+
+- fix: properly apply static textarea value attribute during CSR ([#18727](https://github.com/sveltejs/svelte/pull/18727))
+
+- fix: end a restored reaction context at the end of its synchronous segment ([#18694](https://github.com/sveltejs/svelte/pull/18694))
+
+- fix: keep the dependencies of a reaction that throws, so deriveds it read are neither leaked nor stuck in their error ([#18703](https://github.com/sveltejs/svelte/pull/18703))
+
+- fix: don't resurrect outroing elements when an ancestor block is paused and resumed ([#18431](https://github.com/sveltejs/svelte/pull/18431))
+
+- perf: use `$.comment()` for single-comment templates ([#18714](https://github.com/sveltejs/svelte/pull/18714))
+
+- chore: move `@types/trusted-types` to devDependencies ([#18730](https://github.com/sveltejs/svelte/pull/18730))
+
+- perf: store setters cache as `Set` instead of `Array` ([#18251](https://github.com/sveltejs/svelte/pull/18251))
+
+- fix: transform derived assignments and select function bindings correctly during server-side rendering ([#18669](https://github.com/sveltejs/svelte/pull/18669))
+
+- fix: keep boolean attributes with an empty string value when rendering attribute objects on the server ([#18721](https://github.com/sveltejs/svelte/pull/18721))
+
+- fix: sync `SvelteURL` port signal when the protocol setter clears the port ([#18705](https://github.com/sveltejs/svelte/pull/18705))
+
+- fix: block declaration tags and `{@const}` on async values read inside closures ([#18533](https://github.com/sveltejs/svelte/pull/18533))
+
+- fix: avoid css tree-shaking for exported Snippet ([#18540](https://github.com/sveltejs/svelte/pull/18540))
+
+- perf: treat `<img loading>` as a static element again ([#18711](https://github.com/sveltejs/svelte/pull/18711))
+
+- fix: prevent `selectedcontent` mutation from changing the selected option ([#18495](https://github.com/sveltejs/svelte/pull/18495))
+
+- fix: avoid `NaN` keyframe values in `slide` transition for elements without a layout box ([#18430](https://github.com/sveltejs/svelte/pull/18430))
+
+- fix: preserve line feed character references in attribute values ([#18691](https://github.com/sveltejs/svelte/pull/18691))
+
+- fix: decode uppercase-`X` hex numeric character references (`&#X...;`) ([#18708](https://github.com/sveltejs/svelte/pull/18708))
+
+- chore: clarify when `$effect.pre` runs relative to DOM updates ([#18534](https://github.com/sveltejs/svelte/pull/18534))
+
+- fix: scope SSR boundary failed snippets to their boundary ([#18593](https://github.com/sveltejs/svelte/pull/18593))
+
 ## 5.56.10
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 37489ac109..b8a25432eb 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.56.10",
+  "version": "5.57.0",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index b9f1637abb..46620a618b 100644
--- a/packages/svelte/src/version.js
+++ b/packages/svelte/src/version.js
@@ -4,5 +4,5 @@
  * The current version, as set in package.json.
  * @type {string}
  */
-export const VERSION = '5.56.10';
+export const VERSION = '5.57.0';
 export const PUBLIC_VERSION = '5';

From 214dd3d005e78c90d6c93e76a07b801303f53b53 Mon Sep 17 00:00:00 2001
From: "svelte-triage-bot[bot]"
 <316883489+svelte-triage-bot[bot]@users.noreply.github.com>
Date: Mon, 31 Aug 2026 08:38:45 +0200
Subject: [PATCH 212/222] fix: cancel deferred event listener attachment
 (#18749)

Fixes #18748
---
 .changeset/calm-events-cleanup.md             |  5 +++++
 .../internal/client/dom/elements/events.js    |  7 ++++++-
 .../Child.svelte                              |  1 +
 .../_config.js                                |  8 +++++++
 .../main.svelte                               | 21 +++++++++++++++++++
 5 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/calm-events-cleanup.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/event-cleanup-before-attachment/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/event-cleanup-before-attachment/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/event-cleanup-before-attachment/main.svelte

diff --git a/.changeset/calm-events-cleanup.md b/.changeset/calm-events-cleanup.md
new file mode 100644
index 0000000000..4f5c2357f1
--- /dev/null
+++ b/.changeset/calm-events-cleanup.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: cancel deferred event listeners during cleanup
diff --git a/packages/svelte/src/internal/client/dom/elements/events.js b/packages/svelte/src/internal/client/dom/elements/events.js
index 068c64b9ab..0ed2ffc085 100644
--- a/packages/svelte/src/internal/client/dom/elements/events.js
+++ b/packages/svelte/src/internal/client/dom/elements/events.js
@@ -78,8 +78,11 @@ export function create_event(event_name, dom, handler, options = {}) {
 		event_name.startsWith('touch') ||
 		event_name === 'wheel'
 	) {
+		target_handler.__removed = false;
 		queue_micro_task(() => {
-			dom.addEventListener(event_name, target_handler, options);
+			if (!target_handler.__removed) {
+				dom.addEventListener(event_name, target_handler, options);
+			}
 		});
 	} else {
 		dom.addEventListener(event_name, target_handler, options);
@@ -102,6 +105,7 @@ export function on(element, type, handler, options = {}) {
 	var target_handler = create_event(type, element, handler, options);
 
 	return () => {
+		target_handler.__removed = true;
 		element.removeEventListener(type, target_handler, options);
 	};
 }
@@ -128,6 +132,7 @@ export function event(event_name, dom, handler, capture, passive) {
 		dom instanceof HTMLMediaElement
 	) {
 		teardown(() => {
+			target_handler.__removed = true;
 			dom.removeEventListener(event_name, target_handler, options);
 		});
 	}
diff --git a/packages/svelte/tests/runtime-runes/samples/event-cleanup-before-attachment/Child.svelte b/packages/svelte/tests/runtime-runes/samples/event-cleanup-before-attachment/Child.svelte
new file mode 100644
index 0000000000..98e09b7a20
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/event-cleanup-before-attachment/Child.svelte
@@ -0,0 +1 @@
+<svelte:document onpointerdown={() => console.log('template')} />
diff --git a/packages/svelte/tests/runtime-runes/samples/event-cleanup-before-attachment/_config.js b/packages/svelte/tests/runtime-runes/samples/event-cleanup-before-attachment/_config.js
new file mode 100644
index 0000000000..0e29a46e36
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/event-cleanup-before-attachment/_config.js
@@ -0,0 +1,8 @@
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, logs }) {
+		await new Promise((resolve) => setTimeout(resolve));
+		assert.deepEqual(logs, []);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/event-cleanup-before-attachment/main.svelte b/packages/svelte/tests/runtime-runes/samples/event-cleanup-before-attachment/main.svelte
new file mode 100644
index 0000000000..d5a8f1a201
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/event-cleanup-before-attachment/main.svelte
@@ -0,0 +1,21 @@
+<script>
+	import { mount, onMount, unmount } from 'svelte';
+	import { on } from 'svelte/events';
+	import Child from './Child.svelte';
+
+	let target;
+
+	onMount(async () => {
+		const off = on(document, 'wheel', () => console.log('on'));
+		off();
+
+		const child = mount(Child, { target });
+		unmount(child);
+
+		await Promise.resolve();
+		document.dispatchEvent(new Event('wheel'));
+		document.dispatchEvent(new Event('pointerdown'));
+	});
+</script>
+
+<div bind:this={target}></div>

From 504a7536c6fd1aa2c977503d6a4e7abb2b806902 Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Mon, 31 Aug 2026 04:49:15 -0400
Subject: [PATCH 213/222] perf: stop scanning the whole template for every
 expression (#18738)

Parsing a 90 KB component drops from 460 ms to 35 ms; typical components
parse ~30% faster.

`read_pattern` blanked out the entire template before the pattern with
`replace(/[^\n]/g, ' ')` to keep positions aligned, and
`acorn.parseExpressionAt` re-counted lines from the top of the file on
every call. Acorn never looks before `pos`, so the real template can be
the prefix, and acorn 8.18's `startLocation` takes the line we already
have from the locator.

The blanking also had `loc.column` off by one for every node inside a
destructured pattern (noted in #18087), hence the snapshot updates.
---
 packages/svelte/package.json                  |   2 +-
 .../src/compiler/phases/1-parse/acorn.js      |  31 ++++-
 .../compiler/phases/1-parse/read/context.js   |  21 +--
 .../src/compiler/phases/1-parse/state/tag.js  |   9 +-
 .../each-block-destructured/output.json       |  20 +--
 .../output.json                               | 131 +++++++++---------
 .../each-block-object-pattern/output.json     | 131 +++++++++---------
 .../samples/loose-valid-each-as/output.json   |  21 +--
 pnpm-lock.yaml                                |  47 +++----
 9 files changed, 209 insertions(+), 204 deletions(-)

diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index b8a25432eb..73261b2864 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -175,7 +175,7 @@
     "@jridgewell/sourcemap-codec": "^1.5.0",
     "@sveltejs/acorn-typescript": "^1.0.10",
     "@types/estree": "^1.0.5",
-    "acorn": "^8.12.1",
+    "acorn": "^8.18.0",
     "aria-query": "5.3.1",
     "axobject-query": "^4.1.0",
     "clsx": "^2.1.1",
diff --git a/packages/svelte/src/compiler/phases/1-parse/acorn.js b/packages/svelte/src/compiler/phases/1-parse/acorn.js
index 070183f984..3c3ad2bc8a 100644
--- a/packages/svelte/src/compiler/phases/1-parse/acorn.js
+++ b/packages/svelte/src/compiler/phases/1-parse/acorn.js
@@ -5,6 +5,7 @@ import * as acorn from 'acorn';
 import { walk } from 'zimmerframe';
 import { tsPlugin } from '@sveltejs/acorn-typescript';
 import * as e from '../../errors.js';
+import { locator } from '../../state.js';
 
 const JSParser = acorn.Parser;
 const TSParser = JSParser.extend(tsPlugin());
@@ -87,7 +88,8 @@ export function parse_expression_at(parser, source, index) {
 			sourceType: 'module',
 			ecmaVersion: 16,
 			locations: true,
-			preserveParens: true
+			preserveParens: true,
+			startLocation: start_location(parser, index)
 		});
 
 		add_comments(ast);
@@ -112,7 +114,13 @@ export function parse_statement_at(parser, source, index) {
 	try {
 		// This is like parseExpressionAt but for statements
 		const p = new acorn(
-			{ onComment, sourceType: 'module', ecmaVersion: 16, locations: true },
+			{
+				onComment,
+				sourceType: 'module',
+				ecmaVersion: 16,
+				locations: true,
+				startLocation: start_location(parser, index)
+			},
 			source,
 			index
 		);
@@ -128,6 +136,25 @@ export function parse_statement_at(parser, source, index) {
 	}
 }
 
+const regex_non_lf_line_break = /\r(?!\n)|[\u2028\u2029]/;
+
+let last_template = '';
+let lf_only = true;
+
+/**
+ * Without `startLocation`, acorn counts the lines before `index` on every call.
+ * It also breaks lines on bare `\r`, `\u2028` and `\u2029`, which the locator doesn't, so those templates are left to acorn
+ * @param {Parser} parser
+ * @param {number} index
+ */
+function start_location(parser, index) {
+	if (parser.template !== last_template) {
+		last_template = parser.template;
+		lf_only = !regex_non_lf_line_break.test(last_template);
+	}
+	return lf_only ? locator(index) : undefined;
+}
+
 const regex_position_indicator = / \(\d+:\d+\)$/;
 
 /**
diff --git a/packages/svelte/src/compiler/phases/1-parse/read/context.js b/packages/svelte/src/compiler/phases/1-parse/read/context.js
index cdb239ef5b..821fdcf338 100644
--- a/packages/svelte/src/compiler/phases/1-parse/read/context.js
+++ b/packages/svelte/src/compiler/phases/1-parse/read/context.js
@@ -2,7 +2,6 @@
 /** @import { Parser } from '../index.js' */
 import { match_bracket } from '../utils/bracket.js';
 import { parse_expression_at, remove_parens } from '../acorn.js';
-import { regex_not_newline_characters } from '../../patterns.js';
 import * as e from '../../../errors.js';
 
 /**
@@ -33,24 +32,10 @@ export default function read_pattern(parser) {
 	i = match_bracket(parser, start);
 	parser.index = i;
 
-	const pattern_string = parser.template.slice(start, i);
-
-	// the length of the `space_with_newline` has to be start - 1
-	// because we added a `(` in front of the pattern_string,
-	// which shifted the entire string to right by 1
-	// so we offset it by removing 1 character in the `space_with_newline`
-	// to achieve that, we remove the 1st space encountered,
-	// so it will not affect the `column` of the node
-	let space_with_newline = parser.template
-		.slice(0, start)
-		.replace(regex_not_newline_characters, ' ');
-	const first_space = space_with_newline.indexOf(' ');
-	space_with_newline =
-		space_with_newline.slice(0, first_space) + space_with_newline.slice(first_space + 1);
-
+	// acorn never reads before `start`, so the template itself can serve as the prefix
 	/** @type {any} */
 	let expression = remove_parens(
-		parse_expression_at(parser, `${space_with_newline}(${pattern_string} = 1)`, start - 1)
+		parse_expression_at(parser, parser.template.slice(0, i) + ' = 1', start)
 	);
 
 	expression = expression.left;
@@ -80,7 +65,7 @@ function read_type_annotation(parser) {
 	const insert = '_ as ';
 	let a = parser.index - insert.length;
 	const template =
-		parser.template.slice(0, a).replace(/[^\n]/g, ' ') +
+		parser.template.slice(0, a) +
 		insert +
 		// If this is a type annotation for a function parameter, Acorn-TS will treat subsequent
 		// parameters as part of a sequence expression instead, and will then error on optional
diff --git a/packages/svelte/src/compiler/phases/1-parse/state/tag.js b/packages/svelte/src/compiler/phases/1-parse/state/tag.js
index f5314d04ed..9cc0a41375 100644
--- a/packages/svelte/src/compiler/phases/1-parse/state/tag.js
+++ b/packages/svelte/src/compiler/phases/1-parse/state/tag.js
@@ -488,12 +488,13 @@ function open(parser) {
 			parser.eat(')', true);
 		}
 
-		const prelude = parser.template.slice(0, params_start).replace(/\S/g, ' ');
-		const params = parser.template.slice(params_start, parser.index);
-
 		let function_expression = matched
 			? /** @type {ArrowFunctionExpression} */ (
-					parse_expression_at(parser, prelude + `${params} => {}`, params_start)
+					parse_expression_at(
+						parser,
+						parser.template.slice(0, parser.index) + ' => {}',
+						params_start
+					)
 				)
 			: { params: [] };
 
diff --git a/packages/svelte/tests/parser-legacy/samples/each-block-destructured/output.json b/packages/svelte/tests/parser-legacy/samples/each-block-destructured/output.json
index 684051e304..d87eefe38c 100644
--- a/packages/svelte/tests/parser-legacy/samples/each-block-destructured/output.json
+++ b/packages/svelte/tests/parser-legacy/samples/each-block-destructured/output.json
@@ -82,11 +82,11 @@
 					"loc": {
 						"start": {
 							"line": 5,
-							"column": 19
+							"column": 18
 						},
 						"end": {
 							"line": 5,
-							"column": 40
+							"column": 39
 						}
 					},
 					"elements": [
@@ -97,11 +97,11 @@
 							"loc": {
 								"start": {
 									"line": 5,
-									"column": 20
+									"column": 19
 								},
 								"end": {
 									"line": 5,
-									"column": 23
+									"column": 22
 								}
 							},
 							"name": "key"
@@ -113,11 +113,11 @@
 							"loc": {
 								"start": {
 									"line": 5,
-									"column": 25
+									"column": 24
 								},
 								"end": {
 									"line": 5,
-									"column": 30
+									"column": 29
 								}
 							},
 							"name": "value"
@@ -129,11 +129,11 @@
 							"loc": {
 								"start": {
 									"line": 5,
-									"column": 32
+									"column": 31
 								},
 								"end": {
 									"line": 5,
-									"column": 39
+									"column": 38
 								}
 							},
 							"argument": {
@@ -143,11 +143,11 @@
 								"loc": {
 									"start": {
 										"line": 5,
-										"column": 35
+										"column": 34
 									},
 									"end": {
 										"line": 5,
-										"column": 39
+										"column": 38
 									}
 								},
 								"name": "rest"
diff --git a/packages/svelte/tests/parser-modern/samples/each-block-object-pattern-special-characters/output.json b/packages/svelte/tests/parser-modern/samples/each-block-object-pattern-special-characters/output.json
index 7fd5deb3ea..40127f1ef9 100644
--- a/packages/svelte/tests/parser-modern/samples/each-block-object-pattern-special-characters/output.json
+++ b/packages/svelte/tests/parser-modern/samples/each-block-object-pattern-special-characters/output.json
@@ -170,11 +170,11 @@
 					"loc": {
 						"start": {
 							"line": 3,
-							"column": 13
+							"column": 12
 						},
 						"end": {
 							"line": 3,
-							"column": 24
+							"column": 23
 						}
 					},
 					"properties": [
@@ -185,11 +185,11 @@
 							"loc": {
 								"start": {
 									"line": 3,
-									"column": 15
+									"column": 14
 								},
 								"end": {
 									"line": 3,
-									"column": 22
+									"column": 21
 								}
 							},
 							"method": false,
@@ -202,11 +202,11 @@
 								"loc": {
 									"start": {
 										"line": 3,
-										"column": 15
+										"column": 14
 									},
 									"end": {
 										"line": 3,
-										"column": 16
+										"column": 15
 									}
 								},
 								"name": "y"
@@ -218,11 +218,11 @@
 								"loc": {
 									"start": {
 										"line": 3,
-										"column": 15
+										"column": 14
 									},
 									"end": {
 										"line": 3,
-										"column": 22
+										"column": 21
 									}
 								},
 								"left": {
@@ -232,11 +232,11 @@
 									"loc": {
 										"start": {
 											"line": 3,
-											"column": 15
+											"column": 14
 										},
 										"end": {
 											"line": 3,
-											"column": 16
+											"column": 15
 										}
 									},
 									"name": "y"
@@ -248,11 +248,11 @@
 									"loc": {
 										"start": {
 											"line": 3,
-											"column": 19
+											"column": 18
 										},
 										"end": {
 											"line": 3,
-											"column": 22
+											"column": 21
 										}
 									},
 									"value": "{",
@@ -302,11 +302,11 @@
 					"loc": {
 						"start": {
 							"line": 5,
-							"column": 13
+							"column": 12
 						},
 						"end": {
 							"line": 5,
-							"column": 24
+							"column": 23
 						}
 					},
 					"properties": [
@@ -317,11 +317,11 @@
 							"loc": {
 								"start": {
 									"line": 5,
-									"column": 15
+									"column": 14
 								},
 								"end": {
 									"line": 5,
-									"column": 22
+									"column": 21
 								}
 							},
 							"method": false,
@@ -334,11 +334,11 @@
 								"loc": {
 									"start": {
 										"line": 5,
-										"column": 15
+										"column": 14
 									},
 									"end": {
 										"line": 5,
-										"column": 16
+										"column": 15
 									}
 								},
 								"name": "y"
@@ -350,11 +350,11 @@
 								"loc": {
 									"start": {
 										"line": 5,
-										"column": 15
+										"column": 14
 									},
 									"end": {
 										"line": 5,
-										"column": 22
+										"column": 21
 									}
 								},
 								"left": {
@@ -364,11 +364,11 @@
 									"loc": {
 										"start": {
 											"line": 5,
-											"column": 15
+											"column": 14
 										},
 										"end": {
 											"line": 5,
-											"column": 16
+											"column": 15
 										}
 									},
 									"name": "y"
@@ -380,11 +380,11 @@
 									"loc": {
 										"start": {
 											"line": 5,
-											"column": 19
+											"column": 18
 										},
 										"end": {
 											"line": 5,
-											"column": 22
+											"column": 21
 										}
 									},
 									"value": "]",
@@ -434,11 +434,11 @@
 					"loc": {
 						"start": {
 							"line": 7,
-							"column": 13
+							"column": 12
 						},
 						"end": {
 							"line": 7,
-							"column": 29
+							"column": 28
 						}
 					},
 					"properties": [
@@ -449,11 +449,11 @@
 							"loc": {
 								"start": {
 									"line": 7,
-									"column": 15
+									"column": 14
 								},
 								"end": {
 									"line": 7,
-									"column": 27
+									"column": 26
 								}
 							},
 							"method": false,
@@ -466,11 +466,11 @@
 								"loc": {
 									"start": {
 										"line": 7,
-										"column": 15
+										"column": 14
 									},
 									"end": {
 										"line": 7,
-										"column": 16
+										"column": 15
 									}
 								},
 								"name": "y"
@@ -482,11 +482,11 @@
 								"loc": {
 									"start": {
 										"line": 7,
-										"column": 15
+										"column": 14
 									},
 									"end": {
 										"line": 7,
-										"column": 27
+										"column": 26
 									}
 								},
 								"left": {
@@ -496,11 +496,11 @@
 									"loc": {
 										"start": {
 											"line": 7,
-											"column": 15
+											"column": 14
 										},
 										"end": {
 											"line": 7,
-											"column": 16
+											"column": 15
 										}
 									},
 									"name": "y"
@@ -512,11 +512,11 @@
 									"loc": {
 										"start": {
 											"line": 7,
-											"column": 19
+											"column": 18
 										},
 										"end": {
 											"line": 7,
-											"column": 27
+											"column": 26
 										}
 									},
 									"expressions": [
@@ -527,11 +527,11 @@
 											"loc": {
 												"start": {
 													"line": 7,
-													"column": 22
+													"column": 21
 												},
 												"end": {
 													"line": 7,
-													"column": 25
+													"column": 24
 												}
 											},
 											"expressions": [],
@@ -543,11 +543,11 @@
 													"loc": {
 														"start": {
 															"line": 7,
-															"column": 23
+															"column": 22
 														},
 														"end": {
 															"line": 7,
-															"column": 24
+															"column": 23
 														}
 													},
 													"value": {
@@ -567,11 +567,11 @@
 											"loc": {
 												"start": {
 													"line": 7,
-													"column": 20
+													"column": 19
 												},
 												"end": {
 													"line": 7,
-													"column": 20
+													"column": 19
 												}
 											},
 											"value": {
@@ -587,11 +587,11 @@
 											"loc": {
 												"start": {
 													"line": 7,
-													"column": 26
+													"column": 25
 												},
 												"end": {
 													"line": 7,
-													"column": 26
+													"column": 25
 												}
 											},
 											"value": {
@@ -646,11 +646,11 @@
 					"loc": {
 						"start": {
 							"line": 9,
-							"column": 13
+							"column": 12
 						},
 						"end": {
 							"line": 9,
-							"column": 32
+							"column": 31
 						}
 					},
 					"properties": [
@@ -661,11 +661,11 @@
 							"loc": {
 								"start": {
 									"line": 9,
-									"column": 15
+									"column": 14
 								},
 								"end": {
 									"line": 9,
-									"column": 30
+									"column": 29
 								}
 							},
 							"method": false,
@@ -678,11 +678,11 @@
 								"loc": {
 									"start": {
 										"line": 9,
-										"column": 15
+										"column": 14
 									},
 									"end": {
 										"line": 9,
-										"column": 16
+										"column": 15
 									}
 								},
 								"name": "y"
@@ -694,11 +694,11 @@
 								"loc": {
 									"start": {
 										"line": 9,
-										"column": 15
+										"column": 14
 									},
 									"end": {
 										"line": 9,
-										"column": 30
+										"column": 29
 									}
 								},
 								"left": {
@@ -708,11 +708,11 @@
 									"loc": {
 										"start": {
 											"line": 9,
-											"column": 15
+											"column": 14
 										},
 										"end": {
 											"line": 9,
-											"column": 16
+											"column": 15
 										}
 									},
 									"name": "y"
@@ -724,11 +724,11 @@
 									"loc": {
 										"start": {
 											"line": 9,
-											"column": 19
+											"column": 18
 										},
 										"end": {
 											"line": 9,
-											"column": 30
+											"column": 29
 										}
 									},
 									"expressions": [
@@ -739,11 +739,11 @@
 											"loc": {
 												"start": {
 													"line": 9,
-													"column": 22
+													"column": 21
 												},
 												"end": {
 													"line": 9,
-													"column": 28
+													"column": 27
 												}
 											},
 											"expressions": [],
@@ -755,11 +755,11 @@
 													"loc": {
 														"start": {
 															"line": 9,
-															"column": 23
+															"column": 22
 														},
 														"end": {
 															"line": 9,
-															"column": 27
+															"column": 26
 														}
 													},
 													"value": {
@@ -779,11 +779,11 @@
 											"loc": {
 												"start": {
 													"line": 9,
-													"column": 20
+													"column": 19
 												},
 												"end": {
 													"line": 9,
-													"column": 20
+													"column": 19
 												}
 											},
 											"value": {
@@ -799,11 +799,11 @@
 											"loc": {
 												"start": {
 													"line": 9,
-													"column": 29
+													"column": 28
 												},
 												"end": {
 													"line": 9,
-													"column": 29
+													"column": 28
 												}
 											},
 											"value": {
@@ -822,5 +822,6 @@
 			}
 		]
 	},
-	"options": null
+	"options": null,
+	"comments": []
 }
diff --git a/packages/svelte/tests/parser-modern/samples/each-block-object-pattern/output.json b/packages/svelte/tests/parser-modern/samples/each-block-object-pattern/output.json
index 7e2fe09ea2..60fb4c4c09 100644
--- a/packages/svelte/tests/parser-modern/samples/each-block-object-pattern/output.json
+++ b/packages/svelte/tests/parser-modern/samples/each-block-object-pattern/output.json
@@ -495,11 +495,11 @@
 					"loc": {
 						"start": {
 							"line": 5,
-							"column": 18
+							"column": 17
 						},
 						"end": {
 							"line": 5,
-							"column": 57
+							"column": 56
 						}
 					},
 					"properties": [
@@ -510,11 +510,11 @@
 							"loc": {
 								"start": {
 									"line": 5,
-									"column": 20
+									"column": 19
 								},
 								"end": {
 									"line": 5,
-									"column": 42
+									"column": 41
 								}
 							},
 							"method": false,
@@ -527,11 +527,11 @@
 								"loc": {
 									"start": {
 										"line": 5,
-										"column": 20
+										"column": 19
 									},
 									"end": {
 										"line": 5,
-										"column": 24
+										"column": 23
 									}
 								},
 								"name": "name"
@@ -543,11 +543,11 @@
 								"loc": {
 									"start": {
 										"line": 5,
-										"column": 20
+										"column": 19
 									},
 									"end": {
 										"line": 5,
-										"column": 42
+										"column": 41
 									}
 								},
 								"left": {
@@ -557,11 +557,11 @@
 									"loc": {
 										"start": {
 											"line": 5,
-											"column": 20
+											"column": 19
 										},
 										"end": {
 											"line": 5,
-											"column": 24
+											"column": 23
 										}
 									},
 									"name": "name"
@@ -573,11 +573,11 @@
 									"loc": {
 										"start": {
 											"line": 5,
-											"column": 27
+											"column": 26
 										},
 										"end": {
 											"line": 5,
-											"column": 42
+											"column": 41
 										}
 									},
 									"expressions": [
@@ -588,11 +588,11 @@
 											"loc": {
 												"start": {
 													"line": 5,
-													"column": 35
+													"column": 34
 												},
 												"end": {
 													"line": 5,
-													"column": 40
+													"column": 39
 												}
 											},
 											"value": "Doe",
@@ -607,11 +607,11 @@
 											"loc": {
 												"start": {
 													"line": 5,
-													"column": 28
+													"column": 27
 												},
 												"end": {
 													"line": 5,
-													"column": 33
+													"column": 32
 												}
 											},
 											"value": {
@@ -627,11 +627,11 @@
 											"loc": {
 												"start": {
 													"line": 5,
-													"column": 41
+													"column": 40
 												},
 												"end": {
 													"line": 5,
-													"column": 41
+													"column": 40
 												}
 											},
 											"value": {
@@ -652,11 +652,11 @@
 							"loc": {
 								"start": {
 									"line": 5,
-									"column": 44
+									"column": 43
 								},
 								"end": {
 									"line": 5,
-									"column": 55
+									"column": 54
 								}
 							},
 							"method": false,
@@ -669,11 +669,11 @@
 								"loc": {
 									"start": {
 										"line": 5,
-										"column": 44
+										"column": 43
 									},
 									"end": {
 										"line": 5,
-										"column": 48
+										"column": 47
 									}
 								},
 								"name": "cool"
@@ -685,11 +685,11 @@
 								"loc": {
 									"start": {
 										"line": 5,
-										"column": 44
+										"column": 43
 									},
 									"end": {
 										"line": 5,
-										"column": 55
+										"column": 54
 									}
 								},
 								"left": {
@@ -699,11 +699,11 @@
 									"loc": {
 										"start": {
 											"line": 5,
-											"column": 44
+											"column": 43
 										},
 										"end": {
 											"line": 5,
-											"column": 48
+											"column": 47
 										}
 									},
 									"name": "cool"
@@ -715,11 +715,11 @@
 									"loc": {
 										"start": {
 											"line": 5,
-											"column": 51
+											"column": 50
 										},
 										"end": {
 											"line": 5,
-											"column": 55
+											"column": 54
 										}
 									},
 									"value": true,
@@ -906,11 +906,11 @@
 					"loc": {
 						"start": {
 							"line": 9,
-							"column": 18
+							"column": 17
 						},
 						"end": {
 							"line": 9,
-							"column": 79
+							"column": 78
 						}
 					},
 					"properties": [
@@ -921,11 +921,11 @@
 							"loc": {
 								"start": {
 									"line": 9,
-									"column": 20
+									"column": 19
 								},
 								"end": {
 									"line": 9,
-									"column": 64
+									"column": 63
 								}
 							},
 							"method": false,
@@ -938,11 +938,11 @@
 								"loc": {
 									"start": {
 										"line": 9,
-										"column": 20
+										"column": 19
 									},
 									"end": {
 										"line": 9,
-										"column": 24
+										"column": 23
 									}
 								},
 								"name": "name"
@@ -954,11 +954,11 @@
 								"loc": {
 									"start": {
 										"line": 9,
-										"column": 20
+										"column": 19
 									},
 									"end": {
 										"line": 9,
-										"column": 64
+										"column": 63
 									}
 								},
 								"left": {
@@ -968,11 +968,11 @@
 									"loc": {
 										"start": {
 											"line": 9,
-											"column": 20
+											"column": 19
 										},
 										"end": {
 											"line": 9,
-											"column": 24
+											"column": 23
 										}
 									},
 									"name": "name"
@@ -984,11 +984,11 @@
 									"loc": {
 										"start": {
 											"line": 9,
-											"column": 27
+											"column": 26
 										},
 										"end": {
 											"line": 9,
-											"column": 64
+											"column": 63
 										}
 									},
 									"callee": {
@@ -998,11 +998,11 @@
 										"loc": {
 											"start": {
 												"line": 9,
-												"column": 28
+												"column": 27
 											},
 											"end": {
 												"line": 9,
-												"column": 61
+												"column": 60
 											}
 										},
 										"id": null,
@@ -1017,11 +1017,11 @@
 											"loc": {
 												"start": {
 													"line": 9,
-													"column": 34
+													"column": 33
 												},
 												"end": {
 													"line": 9,
-													"column": 61
+													"column": 60
 												}
 											},
 											"body": [
@@ -1032,11 +1032,11 @@
 													"loc": {
 														"start": {
 															"line": 9,
-															"column": 36
+															"column": 35
 														},
 														"end": {
 															"line": 9,
-															"column": 59
+															"column": 58
 														}
 													},
 													"argument": {
@@ -1046,11 +1046,11 @@
 														"loc": {
 															"start": {
 																"line": 9,
-																"column": 43
+																"column": 42
 															},
 															"end": {
 																"line": 9,
-																"column": 58
+																"column": 57
 															}
 														},
 														"expressions": [
@@ -1061,11 +1061,11 @@
 																"loc": {
 																	"start": {
 																		"line": 9,
-																		"column": 51
+																		"column": 50
 																	},
 																	"end": {
 																		"line": 9,
-																		"column": 56
+																		"column": 55
 																	}
 																},
 																"value": "Doe",
@@ -1080,11 +1080,11 @@
 																"loc": {
 																	"start": {
 																		"line": 9,
-																		"column": 44
+																		"column": 43
 																	},
 																	"end": {
 																		"line": 9,
-																		"column": 49
+																		"column": 48
 																	}
 																},
 																"value": {
@@ -1100,11 +1100,11 @@
 																"loc": {
 																	"start": {
 																		"line": 9,
-																		"column": 57
+																		"column": 56
 																	},
 																	"end": {
 																		"line": 9,
-																		"column": 57
+																		"column": 56
 																	}
 																},
 																"value": {
@@ -1132,11 +1132,11 @@
 							"loc": {
 								"start": {
 									"line": 9,
-									"column": 66
+									"column": 65
 								},
 								"end": {
 									"line": 9,
-									"column": 77
+									"column": 76
 								}
 							},
 							"method": false,
@@ -1149,11 +1149,11 @@
 								"loc": {
 									"start": {
 										"line": 9,
-										"column": 66
+										"column": 65
 									},
 									"end": {
 										"line": 9,
-										"column": 70
+										"column": 69
 									}
 								},
 								"name": "cool"
@@ -1165,11 +1165,11 @@
 								"loc": {
 									"start": {
 										"line": 9,
-										"column": 66
+										"column": 65
 									},
 									"end": {
 										"line": 9,
-										"column": 77
+										"column": 76
 									}
 								},
 								"left": {
@@ -1179,11 +1179,11 @@
 									"loc": {
 										"start": {
 											"line": 9,
-											"column": 66
+											"column": 65
 										},
 										"end": {
 											"line": 9,
-											"column": 70
+											"column": 69
 										}
 									},
 									"name": "cool"
@@ -1195,11 +1195,11 @@
 									"loc": {
 										"start": {
 											"line": 9,
-											"column": 73
+											"column": 72
 										},
 										"end": {
 											"line": 9,
-											"column": 77
+											"column": 76
 										}
 									},
 									"value": true,
@@ -1213,5 +1213,6 @@
 			}
 		]
 	},
-	"options": null
+	"options": null,
+	"comments": []
 }
diff --git a/packages/svelte/tests/parser-modern/samples/loose-valid-each-as/output.json b/packages/svelte/tests/parser-modern/samples/loose-valid-each-as/output.json
index 441cf71519..a4181faf3e 100644
--- a/packages/svelte/tests/parser-modern/samples/loose-valid-each-as/output.json
+++ b/packages/svelte/tests/parser-modern/samples/loose-valid-each-as/output.json
@@ -133,11 +133,11 @@
 					"loc": {
 						"start": {
 							"line": 5,
-							"column": 15
+							"column": 14
 						},
 						"end": {
 							"line": 5,
-							"column": 39
+							"column": 38
 						}
 					},
 					"elements": [
@@ -148,11 +148,11 @@
 							"loc": {
 								"start": {
 									"line": 5,
-									"column": 16
+									"column": 15
 								},
 								"end": {
 									"line": 5,
-									"column": 19
+									"column": 18
 								}
 							},
 							"name": "key"
@@ -164,11 +164,11 @@
 							"loc": {
 								"start": {
 									"line": 5,
-									"column": 21
+									"column": 20
 								},
 								"end": {
 									"line": 5,
-									"column": 38
+									"column": 37
 								}
 							},
 							"left": {
@@ -178,11 +178,11 @@
 								"loc": {
 									"start": {
 										"line": 5,
-										"column": 21
+										"column": 20
 									},
 									"end": {
 										"line": 5,
-										"column": 26
+										"column": 25
 									}
 								},
 								"name": "value"
@@ -194,11 +194,11 @@
 								"loc": {
 									"start": {
 										"line": 5,
-										"column": 29
+										"column": 28
 									},
 									"end": {
 										"line": 5,
-										"column": 38
+										"column": 37
 									}
 								},
 								"value": "default",
@@ -211,6 +211,7 @@
 		]
 	},
 	"options": null,
+	"comments": [],
 	"instance": {
 		"type": "Script",
 		"start": 0,
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index c51620fff5..f9897fb4b4 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -76,13 +76,13 @@ importers:
         version: 1.5.0
       '@sveltejs/acorn-typescript':
         specifier: ^1.0.10
-        version: 1.0.10(acorn@8.16.0)
+        version: 1.0.10(acorn@8.18.0)
       '@types/estree':
         specifier: ^1.0.5
         version: 1.0.8
       acorn:
-        specifier: ^8.12.1
-        version: 8.16.0
+        specifier: ^8.18.0
+        version: 8.18.0
       aria-query:
         specifier: 5.3.1
         version: 5.3.1
@@ -1241,13 +1241,8 @@ packages:
     peerDependencies:
       acorn: ^6.0.0 || ^7.0.0 || ^8.0.0
 
-  acorn@8.16.0:
-    resolution: {integrity: sha512-UVJyE9MttOsBQIDKw1skb9nAwQuR5wuGD3+82K6JgJlm/Y+KI92oNsMNGZCYdDsVtRHSak0pcV5Dno5+4jh9sw==}
-    engines: {node: '>=0.4.0'}
-    hasBin: true
-
-  acorn@8.17.0:
-    resolution: {integrity: sha512-xRQbDb9BnwDafYNn6Vwl839DYVjqXYb1XVGtWAZ1kcDc6iwAL4hg3B1dZlRiuENFeO2H53gFG3in621AdERVAg==}
+  acorn@8.18.0:
+    resolution: {integrity: sha512-lGq+9yr1/GuAWaVYIHRjvvySG5/4VfKIvC8EWxStPdcDh/Ka7FG3twP6v4d5BkravUilhIAsG4Qj83t02LWUPQ==}
     engines: {node: '>=0.4.0'}
     hasBin: true
 
@@ -3302,15 +3297,15 @@ snapshots:
   '@stylistic/eslint-plugin-js@1.8.0(eslint@10.0.0)':
     dependencies:
       '@types/eslint': 8.56.12
-      acorn: 8.17.0
+      acorn: 8.18.0
       escape-string-regexp: 4.0.0
       eslint: 10.0.0
       eslint-visitor-keys: 3.4.3
       espree: 9.6.1
 
-  '@sveltejs/acorn-typescript@1.0.10(acorn@8.16.0)':
+  '@sveltejs/acorn-typescript@1.0.10(acorn@8.18.0)':
     dependencies:
-      acorn: 8.16.0
+      acorn: 8.18.0
 
   '@sveltejs/eslint-config@9.0.0(@eslint/js@10.0.1(eslint@10.0.0))(@stylistic/eslint-plugin-js@1.8.0(eslint@10.0.0))(eslint-config-prettier@9.1.0(eslint@10.0.0))(eslint-plugin-n@17.24.0(eslint@10.0.0)(typescript@5.5.4))(eslint-plugin-svelte@3.15.0(eslint@10.0.0)(svelte@packages+svelte))(eslint@10.0.0)(typescript-eslint@8.56.0(eslint@10.0.0)(typescript@5.5.4))(typescript@5.5.4)':
     dependencies:
@@ -3532,17 +3527,11 @@ snapshots:
       convert-source-map: 2.0.0
       tinyrainbow: 3.1.0
 
-  acorn-jsx@5.3.2(acorn@8.16.0):
+  acorn-jsx@5.3.2(acorn@8.18.0):
     dependencies:
-      acorn: 8.16.0
-
-  acorn-jsx@5.3.2(acorn@8.17.0):
-    dependencies:
-      acorn: 8.17.0
-
-  acorn@8.16.0: {}
+      acorn: 8.18.0
 
-  acorn@8.17.0: {}
+  acorn@8.18.0: {}
 
   agent-base@7.1.1:
     dependencies:
@@ -3898,20 +3887,20 @@ snapshots:
 
   espree@10.1.0:
     dependencies:
-      acorn: 8.16.0
-      acorn-jsx: 5.3.2(acorn@8.16.0)
+      acorn: 8.18.0
+      acorn-jsx: 5.3.2(acorn@8.18.0)
       eslint-visitor-keys: 4.2.1
 
   espree@11.1.0:
     dependencies:
-      acorn: 8.16.0
-      acorn-jsx: 5.3.2(acorn@8.16.0)
+      acorn: 8.18.0
+      acorn-jsx: 5.3.2(acorn@8.18.0)
       eslint-visitor-keys: 5.0.0
 
   espree@9.6.1:
     dependencies:
-      acorn: 8.17.0
-      acorn-jsx: 5.3.2(acorn@8.17.0)
+      acorn: 8.18.0
+      acorn-jsx: 5.3.2(acorn@8.18.0)
       eslint-visitor-keys: 3.4.3
 
   esprima@4.0.1: {}
@@ -4664,7 +4653,7 @@ snapshots:
   terser@5.27.0:
     dependencies:
       '@jridgewell/source-map': 0.3.6
-      acorn: 8.16.0
+      acorn: 8.18.0
       commander: 2.20.3
       source-map-support: 0.5.21
 

From 34142af3a1125dd512bfb88b396a2e1de1dace45 Mon Sep 17 00:00:00 2001
From: Nic Polumeyv <nicolas.polum@outlook.com>
Date: Mon, 31 Aug 2026 04:49:16 -0400
Subject: [PATCH 214/222] perf: build identifier and member chain expressions
 without acorn (#18740)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

After #18738 the biggest thing left in the parser profile was acorn's
constructor, `getOptions` and `wordsRegexp` alone were around 12% of
parse time. `parseExpressionAt` is `new Parser()` followed by
`parseExpression()`, and we call it for every expression in the
template. For something like `{name}` the constructor (normalizing
options, four keyword regexes, scope state) is about 2 µs while the
actual parse is under 1 µs, and components have dozens of these.

The fix seemed to belong in acorn, cache the options and regexes so
repeated `parseExpressionAt` calls stop redoing them. I lasted about
twenty minutes in acorn's constructor... I was way in over my head. The
Svelte alternative was one parser per component, reset between
expressions, but that means re-initializing acorn's and
acorn-typescript's internals by hand and breaking whenever either adds a
field.

I realized most of the expressions in the test corpus are an identifier
or an `a.b.c` chain, and you don't need a JS parser for those. So that's
this fix. `read_expression` now scans for that shape, builds the nodes
itself in the form acorn would, and hands everything else to acorn like
before.No behavior change, verified byte-for-byte against acorn on the
test corpus.

About 18% faster parsing on typical components on top of #18738.

I guess this should be a fix for acorn, rather than here, so I'm not
against closing this.

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/easy-points-tan.md                 |   5 +
 .../src/compiler/phases/1-parse/acorn.js      |  13 +-
 .../phases/1-parse/read/expression.js         | 112 +++++++++++++++++-
 3 files changed, 125 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/easy-points-tan.md

diff --git a/.changeset/easy-points-tan.md b/.changeset/easy-points-tan.md
new file mode 100644
index 0000000000..60edbf94eb
--- /dev/null
+++ b/.changeset/easy-points-tan.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+perf: speed up parser interactions with Acorn or avoid them where possible
diff --git a/packages/svelte/src/compiler/phases/1-parse/acorn.js b/packages/svelte/src/compiler/phases/1-parse/acorn.js
index 3c3ad2bc8a..add61ea19f 100644
--- a/packages/svelte/src/compiler/phases/1-parse/acorn.js
+++ b/packages/svelte/src/compiler/phases/1-parse/acorn.js
@@ -142,17 +142,24 @@ let last_template = '';
 let lf_only = true;
 
 /**
- * Without `startLocation`, acorn counts the lines before `index` on every call.
- * It also breaks lines on bare `\r`, `\u2028` and `\u2029`, which the locator doesn't, so those templates are left to acorn
+ * Without `startLocation`, acorn counts the lines before `index` on every call
  * @param {Parser} parser
  * @param {number} index
  */
 function start_location(parser, index) {
+	return has_lf_line_breaks_only(parser) ? locator(index) : undefined;
+}
+
+/**
+ * acorn breaks lines on bare `\r`, `\u2028` and `\u2029`, which the locator doesn't
+ * @param {Parser} parser
+ */
+export function has_lf_line_breaks_only(parser) {
 	if (parser.template !== last_template) {
 		last_template = parser.template;
 		lf_only = !regex_non_lf_line_break.test(last_template);
 	}
-	return lf_only ? locator(index) : undefined;
+	return lf_only;
 }
 
 const regex_position_indicator = / \(\d+:\d+\)$/;
diff --git a/packages/svelte/src/compiler/phases/1-parse/read/expression.js b/packages/svelte/src/compiler/phases/1-parse/read/expression.js
index 1c8f097c2f..b63ad443a8 100644
--- a/packages/svelte/src/compiler/phases/1-parse/read/expression.js
+++ b/packages/svelte/src/compiler/phases/1-parse/read/expression.js
@@ -1,9 +1,13 @@
-/** @import { Expression } from 'estree' */
+/** @import { Expression, Identifier } from 'estree' */
 /** @import { Parser } from '../index.js' */
-import { parse_expression_at, remove_parens } from '../acorn.js';
+// @ts-expect-error acorn type definitions are borked in the release we use
+import { isIdentifierStart, isIdentifierChar } from 'acorn';
+import { has_lf_line_breaks_only, parse_expression_at, remove_parens } from '../acorn.js';
 import { regex_whitespace } from '../../patterns.js';
 import * as e from '../../../errors.js';
 import { find_matching_bracket } from '../utils/bracket.js';
+import { is_reserved } from '../../../../utils.js';
+import { locator } from '../../../state.js';
 
 /**
  * @param {Parser} parser
@@ -33,6 +37,9 @@ export function get_loose_identifier(parser, opening_token) {
  * @returns {Expression}
  */
 export default function read_expression(parser, opening_token, disallow_loose) {
+	const simple = read_simple_expression(parser);
+	if (simple) return simple;
+
 	try {
 		const node = parse_expression_at(parser, parser.template, parser.index);
 
@@ -57,3 +64,104 @@ export default function read_expression(parser, opening_token, disallow_loose) {
 		throw err;
 	}
 }
+
+/**
+ * Most template expressions are an identifier or a `a.b.c` member chain followed by `}`.
+ * Those are built directly for better parse performance, with the same shape acorn would produce; anything else goes to acorn
+ * @param {Parser} parser
+ * @returns {Expression | null}
+ */
+function read_simple_expression(parser) {
+	if (!has_lf_line_breaks_only(parser)) return null;
+
+	const template = parser.template;
+	const index = parser.index;
+
+	parser.allow_whitespace();
+	const start = parser.index;
+
+	let end = read_word(template, start);
+	if (end === -1 || is_reserved(template.slice(start, end))) {
+		parser.index = index;
+		return null;
+	}
+
+	/** @type {Expression} */
+	let node = identifier(template, start, end);
+
+	while (template[end] === '.') {
+		const property_end = read_word(template, end + 1);
+		if (property_end === -1) {
+			parser.index = index;
+			return null;
+		}
+
+		node = {
+			type: 'MemberExpression',
+			start,
+			end: property_end,
+			loc: { start: position(start), end: position(property_end) },
+			object: node,
+			property: identifier(template, end + 1, property_end),
+			computed: false,
+			optional: false
+		};
+
+		end = property_end;
+	}
+
+	parser.index = end;
+	parser.allow_whitespace();
+
+	if (!parser.match('}')) {
+		parser.index = index;
+		return null;
+	}
+
+	parser.index = end;
+	return node;
+}
+
+/**
+ * @param {string} template
+ * @param {number} start
+ * @returns {number} the end of the identifier starting at `start`, or -1
+ */
+function read_word(template, start) {
+	if (start >= template.length) return -1;
+
+	const code = /** @type {number} */ (template.codePointAt(start));
+	if (!isIdentifierStart(code, true)) return -1;
+
+	let end = start + (code <= 0xffff ? 1 : 2);
+
+	while (end < template.length) {
+		const code = /** @type {number} */ (template.codePointAt(end));
+		if (!isIdentifierChar(code, true)) break;
+		end += code <= 0xffff ? 1 : 2;
+	}
+
+	return end;
+}
+
+/**
+ * @param {string} template
+ * @param {number} start
+ * @param {number} end
+ * @returns {Identifier}
+ */
+function identifier(template, start, end) {
+	return {
+		type: 'Identifier',
+		start,
+		end,
+		loc: { start: position(start), end: position(end) },
+		name: template.slice(start, end)
+	};
+}
+
+/** @param {number} index */
+function position(index) {
+	const { line, column } = locator(index);
+	return { line, column };
+}

From b1142efe966cc7091fb6d79b1756e79ad97b4f59 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Mon, 31 Aug 2026 14:19:55 +0200
Subject: [PATCH 215/222] perf: speed up parser a little bit (#18736)

~5% in local benchmarks by avoiding regex in some places
---
 .changeset/tall-kids-juggle.md                |   5 +
 .../src/compiler/phases/1-parse/index.js      |  42 ++++----
 .../compiler/phases/1-parse/read/script.js    |   2 +-
 .../src/compiler/phases/1-parse/read/style.js |   8 +-
 .../compiler/phases/1-parse/state/element.js  | 100 +++++++++++-------
 .../src/compiler/phases/1-parse/utils/html.js |   2 +
 .../phases/1-parse/utils/whitespace.js        |  18 ++++
 packages/svelte/src/compiler/state.js         |  14 ++-
 .../src/compiler/utils/compile_diagnostic.js  |   2 +-
 9 files changed, 123 insertions(+), 70 deletions(-)
 create mode 100644 .changeset/tall-kids-juggle.md
 create mode 100644 packages/svelte/src/compiler/phases/1-parse/utils/whitespace.js

diff --git a/.changeset/tall-kids-juggle.md b/.changeset/tall-kids-juggle.md
new file mode 100644
index 0000000000..f116590a28
--- /dev/null
+++ b/.changeset/tall-kids-juggle.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+perf: avoid regex matching in parser where possible
diff --git a/packages/svelte/src/compiler/phases/1-parse/index.js b/packages/svelte/src/compiler/phases/1-parse/index.js
index fa7b292640..8edd403487 100644
--- a/packages/svelte/src/compiler/phases/1-parse/index.js
+++ b/packages/svelte/src/compiler/phases/1-parse/index.js
@@ -10,25 +10,7 @@ import read_options from './read/options.js';
 import { is_reserved } from '../../../utils.js';
 import { disallow_children } from '../2-analyze/visitors/shared/special-element.js';
 import * as state from '../../state.js';
-
-/** @param {number} cc */
-function is_whitespace(cc) {
-	// fast path for common whitespace
-	if (cc === 32 || (cc <= 13 && cc >= 9)) return true;
-	// rare whitespace — \u00a0, \u1680, \u2000-\u200a, \u2028, \u2029, \u202f, \u205f, \u3000, \ufeff
-	if (cc < 160) return false;
-	return (
-		cc === 160 ||
-		cc === 5760 ||
-		(cc >= 8192 && cc <= 8202) ||
-		cc === 8232 ||
-		cc === 8233 ||
-		cc === 8239 ||
-		cc === 8287 ||
-		cc === 12288 ||
-		cc === 65279
-	);
-}
+import { is_whitespace } from './utils/whitespace.js';
 
 const regex_lang_attribute =
 	/<!--[^]*?-->|<script\s+(?:[^>]*|(?:[^=>'"/]+=(?:"[^"]*"|'[^']*'|[^>\s]+)\s+)*)lang=(["'])?([^"' >]+)\1[^>]*>/g;
@@ -278,8 +260,27 @@ export class Parser {
 		};
 	}
 
+	/** @param {string} delimiter */
+	read_until(delimiter) {
+		if (this.index >= this.template.length) {
+			if (this.loose) return '';
+			e.unexpected_eof(this.template.length);
+		}
+
+		const start = this.index;
+		const index = this.template.indexOf(delimiter, start);
+
+		if (index !== -1) {
+			this.index = index;
+			return this.template.slice(start, this.index);
+		}
+
+		this.index = this.template.length;
+		return this.template.slice(start);
+	}
+
 	/** @param {RegExp} pattern */
-	read_until(pattern) {
+	read_until_regex(pattern) {
 		if (this.index >= this.template.length) {
 			if (this.loose) return '';
 			e.unexpected_eof(this.template.length);
@@ -302,6 +303,7 @@ export class Parser {
 			e.expected_whitespace(this.index);
 		}
 
+		this.index++;
 		this.allow_whitespace();
 	}
 
diff --git a/packages/svelte/src/compiler/phases/1-parse/read/script.js b/packages/svelte/src/compiler/phases/1-parse/read/script.js
index 4472ce61c3..48fb540f9c 100644
--- a/packages/svelte/src/compiler/phases/1-parse/read/script.js
+++ b/packages/svelte/src/compiler/phases/1-parse/read/script.js
@@ -22,7 +22,7 @@ const ALLOWED_ATTRIBUTES = ['context', 'generics', 'lang', 'module'];
  */
 export function read_script(parser, start, attributes) {
 	const script_start = parser.index;
-	const data = parser.read_until(regex_closing_script_tag);
+	const data = parser.read_until_regex(regex_closing_script_tag);
 	if (parser.index >= parser.template.length) {
 		e.element_unclosed(parser.template.length, 'script');
 	}
diff --git a/packages/svelte/src/compiler/phases/1-parse/read/style.js b/packages/svelte/src/compiler/phases/1-parse/read/style.js
index df036d0d33..574c353adb 100644
--- a/packages/svelte/src/compiler/phases/1-parse/read/style.js
+++ b/packages/svelte/src/compiler/phases/1-parse/read/style.js
@@ -16,8 +16,6 @@ const REGEX_WHITESPACE_OR_COLON = /[\s:]/;
 const REGEX_LEADING_HYPHEN_OR_DIGIT = /-?\d/y;
 const REGEX_VALID_IDENTIFIER_CHAR = /[a-zA-Z0-9_-]/;
 const REGEX_UNICODE_SEQUENCE = /\\[0-9a-fA-F]{1,6}(\r\n|\s)?/y;
-const REGEX_COMMENT_CLOSE = /\*\//;
-const REGEX_HTML_COMMENT_CLOSE = /-->/;
 
 /**
  * @param {Parser} parser
@@ -478,7 +476,7 @@ function read_block_item(parser) {
 function read_declaration(parser) {
 	const start = parser.index;
 
-	const property = parser.read_until(REGEX_WHITESPACE_OR_COLON);
+	const property = parser.read_until_regex(REGEX_WHITESPACE_OR_COLON);
 	parser.allow_whitespace();
 	parser.eat(':');
 	let index = parser.index;
@@ -661,7 +659,7 @@ function allow_comment_or_whitespace(parser, capture_comments = true) {
 		}
 
 		if (parser.eat('<!--')) {
-			parser.read_until(REGEX_HTML_COMMENT_CLOSE);
+			parser.read_until('-->');
 			parser.eat('-->', true);
 		}
 
@@ -676,7 +674,7 @@ function allow_comment_or_whitespace(parser, capture_comments = true) {
 function read_comment(parser) {
 	const start = parser.index;
 	parser.eat('/*', true);
-	const value = parser.read_until(REGEX_COMMENT_CLOSE);
+	const value = parser.read_until('*/');
 	parser.eat('*/', true);
 	const end = parser.index;
 
diff --git a/packages/svelte/src/compiler/phases/1-parse/state/element.js b/packages/svelte/src/compiler/phases/1-parse/state/element.js
index a14dd167a5..220fe24b9d 100644
--- a/packages/svelte/src/compiler/phases/1-parse/state/element.js
+++ b/packages/svelte/src/compiler/phases/1-parse/state/element.js
@@ -15,13 +15,10 @@ import { get_attribute_expression, is_expression_attribute } from '../../../util
 import { closing_tag_omitted } from '../../../../html-tree-validation.js';
 import { list } from '../../../utils/string.js';
 import { locator } from '../../../state.js';
-import * as b from '#compiler/builders';
+import { is_whitespace } from '../utils/whitespace.js';
 
 const regex_invalid_unquoted_attribute_value = /(\/>|[\s"'=<>`])/y;
 const regex_closing_textarea_tag = /<\/textarea(\s[^>]*)?>/iy;
-const regex_closing_comment = /-->/;
-const regex_whitespace_or_slash_or_closing_tag = /(\s|\/|>)/;
-const regex_token_ending_character = /[\s=/>"']/;
 const regex_starts_with_quote_characters = /["']/y;
 const regex_attribute_value = /(?:"([^"]*)"|'([^'])*'|([^>\s]+))/y;
 const regex_doctype_name = /^![a-zA-Z]+$/;
@@ -67,7 +64,7 @@ export default function element(parser) {
 	let parent = parser.current();
 
 	if (parser.eat('!--')) {
-		const data = parser.read_until(regex_closing_comment);
+		const data = parser.read_until('-->');
 		parser.eat('-->', true);
 
 		parser.append({
@@ -81,7 +78,7 @@ export default function element(parser) {
 	}
 
 	if (parser.eat('/')) {
-		const name = parser.read_until(regex_whitespace_or_slash_or_closing_tag);
+		const name = read_tag_name(parser);
 
 		parser.allow_whitespace();
 		parser.eat('>', true);
@@ -137,7 +134,7 @@ export default function element(parser) {
 		return;
 	}
 
-	const tag = read_tag(parser, regex_whitespace_or_slash_or_closing_tag);
+	const tag = read_tag(parser);
 
 	if (tag.name.startsWith('svelte:') && !meta_tags.has(tag.name)) {
 		const bounds = { start: start + 1, end: start + 1 + tag.name.length };
@@ -475,7 +472,7 @@ function parent_is_shadowroot_template(stack) {
 function read_static_attribute(parser) {
 	const start = parser.index;
 
-	const tag = read_tag(parser, regex_token_ending_character);
+	const tag = read_tag(parser, true);
 	if (!tag.name) return null;
 
 	/** @type {true | Array<AST.Text | AST.ExpressionTag>} */
@@ -607,7 +604,7 @@ function read_attribute(parser) {
 		}
 	}
 
-	const tag = read_tag(parser, regex_token_ending_character);
+	const tag = read_tag(parser, true);
 
 	if (!tag.name) return null;
 
@@ -731,7 +728,7 @@ function read_comment(parser) {
 	const start = parser.index;
 
 	if (parser.eat('//')) {
-		const value = parser.read_until(/\n/);
+		const value = parser.read_until('\n');
 		const end = parser.index;
 
 		return {
@@ -747,7 +744,7 @@ function read_comment(parser) {
 	}
 
 	if (parser.eat('/*')) {
-		const value = parser.read_until(/\*\//);
+		const value = parser.read_until('*/');
 
 		parser.eat('*/');
 		const end = parser.index;
@@ -847,25 +844,21 @@ function read_attribute_value(parser) {
  * @returns {any[]}
  */
 function read_sequence(parser, done, location) {
-	/** @type {AST.Text} */
-	let current_chunk = {
-		start: parser.index,
-		end: -1,
-		type: 'Text',
-		raw: '',
-		data: ''
-	};
-
 	/** @type {Array<AST.Text | AST.ExpressionTag>} */
 	const chunks = [];
+	let chunk_start = parser.index;
 
 	/** @param {number} end */
 	function flush(end) {
-		if (end > current_chunk.start) {
-			current_chunk.raw = parser.template.slice(current_chunk.start, end);
-			current_chunk.data = decode_character_references(current_chunk.raw, true);
-			current_chunk.end = end;
-			chunks.push(current_chunk);
+		if (end > chunk_start) {
+			const raw = parser.template.slice(chunk_start, end);
+			chunks.push({
+				start: chunk_start,
+				end,
+				type: 'Text',
+				raw,
+				data: decode_character_references(raw, true)
+			});
 		}
 	}
 
@@ -879,12 +872,14 @@ function read_sequence(parser, done, location) {
 			if (parser.match('#')) {
 				const index = parser.index - 1;
 				parser.eat('#');
-				const name = parser.read_until(/[^a-z]/);
+				// const name = parser.read_until_regex(/[^a-z]/);
+				const name = read_lowercase_name(parser);
 				e.block_invalid_placement(index, name, location);
 			} else if (parser.match('@')) {
 				const index = parser.index - 1;
 				parser.eat('@');
-				const name = parser.read_until(/[^a-z]/);
+				// const name = parser.read_until_regex(/[^a-z]/);
+				const name = read_lowercase_name(parser);
 				e.tag_invalid_placement(index, name, location);
 			}
 
@@ -907,14 +902,7 @@ function read_sequence(parser, done, location) {
 			};
 
 			chunks.push(chunk);
-
-			current_chunk = {
-				start: parser.index,
-				end: -1,
-				type: 'Text',
-				raw: '',
-				data: ''
-			};
+			chunk_start = parser.index;
 		} else {
 			parser.index++;
 		}
@@ -929,12 +917,36 @@ function read_sequence(parser, done, location) {
 
 /**
  * @param {Parser} parser
- * @param {RegExp} regex
+ * @param {boolean} [attribute]
+ */
+function read_tag_name(parser, attribute = false) {
+	const start = parser.index;
+	if (start >= parser.template.length && !parser.loose) e.unexpected_eof(parser.template.length);
+
+	while (parser.index < parser.template.length) {
+		const cc = parser.template.charCodeAt(parser.index);
+		if (
+			is_whitespace(cc) ||
+			cc === 47 || // /
+			cc === 62 || // >
+			(attribute && (cc === 34 || cc === 39 || cc === 61)) // " ' =
+		) {
+			break;
+		}
+		parser.index += 1;
+	}
+
+	return parser.template.slice(start, parser.index);
+}
+
+/**
+ * @param {Parser} parser
+ * @param {boolean} [attribute]
  * @returns {Identifier & { start: number, end: number, loc: SourceLocation }}
  */
-function read_tag(parser, regex) {
+function read_tag(parser, attribute = false) {
 	const start = parser.index;
-	const name = parser.read_until(regex);
+	const name = read_tag_name(parser, attribute);
 	const end = parser.index;
 
 	return {
@@ -948,3 +960,15 @@ function read_tag(parser, regex) {
 		}
 	};
 }
+
+/** @param {Parser} parser */
+function read_lowercase_name(parser) {
+	const start = parser.index;
+	while (parser.index < parser.template.length) {
+		const cc = parser.template.charCodeAt(parser.index);
+		// a-z
+		if (cc < 97 || cc > 122) break;
+		parser.index += 1;
+	}
+	return parser.template.slice(start, parser.index);
+}
diff --git a/packages/svelte/src/compiler/phases/1-parse/utils/html.js b/packages/svelte/src/compiler/phases/1-parse/utils/html.js
index ccb2005054..dd0b0224a6 100644
--- a/packages/svelte/src/compiler/phases/1-parse/utils/html.js
+++ b/packages/svelte/src/compiler/phases/1-parse/utils/html.js
@@ -38,6 +38,8 @@ const entity_pattern_attr_value = get_entity_pattern(true);
  * @param {boolean} is_attribute_value
  */
 export function decode_character_references(html, is_attribute_value) {
+	if (html.indexOf('&') === -1) return html; // fast path
+
 	const entity_pattern = is_attribute_value ? entity_pattern_attr_value : entity_pattern_content;
 	return html.replace(
 		entity_pattern,
diff --git a/packages/svelte/src/compiler/phases/1-parse/utils/whitespace.js b/packages/svelte/src/compiler/phases/1-parse/utils/whitespace.js
new file mode 100644
index 0000000000..b9a7efc9a3
--- /dev/null
+++ b/packages/svelte/src/compiler/phases/1-parse/utils/whitespace.js
@@ -0,0 +1,18 @@
+/** @param {number} cc */
+export function is_whitespace(cc) {
+	// fast path for common whitespace
+	if (cc === 32 || (cc <= 13 && cc >= 9)) return true;
+	// rare whitespace — \u00a0, \u1680, \u2000-\u200a, \u2028, \u2029, \u202f, \u205f, \u3000, \ufeff
+	if (cc < 160) return false;
+	return (
+		cc === 160 ||
+		cc === 5760 ||
+		(cc >= 8192 && cc <= 8202) ||
+		cc === 8232 ||
+		cc === 8233 ||
+		cc === 8239 ||
+		cc === 8287 ||
+		cc === 12288 ||
+		cc === 65279
+	);
+}
diff --git a/packages/svelte/src/compiler/state.js b/packages/svelte/src/compiler/state.js
index 5ae001ec50..51a02a61e1 100644
--- a/packages/svelte/src/compiler/state.js
+++ b/packages/svelte/src/compiler/state.js
@@ -33,10 +33,14 @@ export let component_name = '<unknown>';
 export let source;
 
 /**
- * The source code split into lines (set by `set_source`)
- * @type {string[]}
+ * The source code split into lines, initialized when a diagnostic needs a code frame
+ * @type {string[] | undefined}
  */
-export let source_lines = [];
+let source_lines;
+
+export function get_source_lines() {
+	return (source_lines ??= source.split('\n'));
+}
 
 /**
  * True if compiling with `dev: true`
@@ -52,7 +56,7 @@ export let locator;
 /** @param {string} value */
 export function set_source(value) {
 	source = value;
-	source_lines = source.split('\n');
+	source_lines = undefined;
 
 	const l = getLocator(source, { offsetLine: 1 });
 
@@ -141,7 +145,7 @@ export function reset(state) {
 	runes = false;
 	component_name = UNKNOWN_FILENAME;
 	source = '';
-	source_lines = [];
+	source_lines = undefined;
 	filename = (state.filename ?? UNKNOWN_FILENAME).replace(/\\/g, '/');
 	warning_filter = state.warning ?? (() => true);
 	warnings = [];
diff --git a/packages/svelte/src/compiler/utils/compile_diagnostic.js b/packages/svelte/src/compiler/utils/compile_diagnostic.js
index 95d028ee35..ab0732c958 100644
--- a/packages/svelte/src/compiler/utils/compile_diagnostic.js
+++ b/packages/svelte/src/compiler/utils/compile_diagnostic.js
@@ -15,7 +15,7 @@ function tabs_to_spaces(str) {
  * @param {number} column
  */
 function get_code_frame(line, column) {
-	const lines = state.source_lines;
+	const lines = state.get_source_lines();
 	const frame_start = Math.max(0, line - 2);
 	const frame_end = Math.min(line + 3, lines.length);
 	const digits = String(frame_end + 1).length;

From b2c22ab66d0978dfa14bb92196a6ab45ad0031a4 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Mon, 31 Aug 2026 14:25:50 +0200
Subject: [PATCH 216/222] chore: add regression test for teardown value
 behavior (#18751)

#18746 would've introduced a bug that makes this test fail. Add it now
so we don't regress in the future
---
 .../effect-loop-teardown-value/_config.js     |  9 ++++++
 .../effect-loop-teardown-value/main.svelte    | 28 +++++++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 packages/svelte/tests/runtime-runes/samples/effect-loop-teardown-value/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/effect-loop-teardown-value/main.svelte

diff --git a/packages/svelte/tests/runtime-runes/samples/effect-loop-teardown-value/_config.js b/packages/svelte/tests/runtime-runes/samples/effect-loop-teardown-value/_config.js
new file mode 100644
index 0000000000..9dc79c3c5a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/effect-loop-teardown-value/_config.js
@@ -0,0 +1,9 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	test({ assert, target, logs }) {
+		flushSync(() => target.querySelector('button')?.click());
+		assert.deepEqual(logs, ['setup: two', 'cleanup: two']);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/effect-loop-teardown-value/main.svelte b/packages/svelte/tests/runtime-runes/samples/effect-loop-teardown-value/main.svelte
new file mode 100644
index 0000000000..b57cfd65e0
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/effect-loop-teardown-value/main.svelte
@@ -0,0 +1,28 @@
+<script>
+	let start = $state(false);
+	let enabled = $state(false);
+	let advance = $state(false);
+	let value = $state('one');
+
+	$effect(() => {
+		if (start) {
+			value = 'two';
+			enabled = true;
+		}
+	});
+
+	$effect(() => {
+		if (enabled) {
+			console.log(`setup: ${value}`);
+			advance = true;
+
+			return () => console.log(`cleanup: ${value}`);
+		}
+	});
+
+	$effect(() => {
+		if (advance) enabled = false;
+	});
+</script>
+
+<button onclick={() => (start = true)}>start</button>

From b580455c9cf5c903c1726866e6808b81332480fc Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Mon, 31 Aug 2026 14:58:37 +0200
Subject: [PATCH 217/222] fix: serialize input default values during SSR
 (#18733)

Alternative to #18452

---------

Co-authored-by: svelte-triage-bot <team@svelte.com>
---
 .changeset/green-inputs-ssr.md                        |  5 +++++
 .../3-transform/server/visitors/shared/element.js     |  8 ++++++++
 packages/svelte/src/internal/server/index.js          | 11 +++++++++--
 .../samples/input-default-value/_config.js            |  3 +++
 .../samples/input-default-value/_expected.html        |  6 ++++++
 .../samples/input-default-value/main.svelte           | 10 ++++++++++
 6 files changed, 41 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/green-inputs-ssr.md
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/input-default-value/_config.js
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/input-default-value/_expected.html
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/input-default-value/main.svelte

diff --git a/.changeset/green-inputs-ssr.md b/.changeset/green-inputs-ssr.md
new file mode 100644
index 0000000000..e034d0e79a
--- /dev/null
+++ b/.changeset/green-inputs-ssr.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: serialize input default values during server rendering
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js
index b4f4facb5d..c19d760f48 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js
@@ -80,6 +80,14 @@ export function build_element_attributes(node, context, transform) {
 				) {
 					events_to_capture.add(attribute.name);
 				}
+			} else if (
+				node.type === 'RegularElement' &&
+				node.name === 'input' &&
+				(attribute.name === 'defaultValue' || attribute.name === 'defaultChecked')
+			) {
+				attributes.push(attribute);
+				// deopt to spread at runtime, where we can handle interaction of value/defaultValue etc
+				has_spread = true;
 				// the defaultValue/defaultChecked properties don't exist as attributes
 			} else if (attribute.name !== 'defaultValue' && attribute.name !== 'defaultChecked') {
 				if (attribute.name === 'class') {
diff --git a/packages/svelte/src/internal/server/index.js b/packages/svelte/src/internal/server/index.js
index 3d8ec5fe5e..20bef78306 100644
--- a/packages/svelte/src/internal/server/index.js
+++ b/packages/svelte/src/internal/server/index.js
@@ -146,8 +146,10 @@ export function attributes(attrs, css_hash, classes, styles, flags = 0) {
 	const is_html = (flags & ELEMENT_IS_NAMESPACED) === 0;
 	const lowercase = (flags & ELEMENT_PRESERVE_ATTRIBUTE_CASE) === 0;
 	const is_input = (flags & ELEMENT_IS_INPUT) !== 0;
+	const names = Object.keys(attrs);
 
-	for (name of Object.keys(attrs)) {
+	outer: for (let i = 0; i < names.length; i++) {
+		name = names[i];
 		// omit functions, internal svelte properties and invalid attribute names
 		if (typeof attrs[name] === 'function') continue;
 		if (name[0] === '$' && name[1] === '$') continue; // faster than name.startsWith('$$')
@@ -163,8 +165,13 @@ export function attributes(attrs, css_hash, classes, styles, flags = 0) {
 
 		if (is_input) {
 			if (name === 'defaultvalue' || name === 'defaultchecked') {
+				// value/checked takes precedence over defaultValue/defaultChecked
 				name = name === 'defaultvalue' ? 'value' : 'checked';
-				if (attrs[name]) continue;
+				if (name in attrs) continue;
+				// We're checking prior entries aswell because "name in attrs" is not enough as the attributes may have different casing
+				for (let j = 0; j < names.length; j++) {
+					if (names[j].toLowerCase() === name) continue outer;
+				}
 			}
 		}
 
diff --git a/packages/svelte/tests/server-side-rendering/samples/input-default-value/_config.js b/packages/svelte/tests/server-side-rendering/samples/input-default-value/_config.js
new file mode 100644
index 0000000000..f47bee71df
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/input-default-value/_config.js
@@ -0,0 +1,3 @@
+import { test } from '../../test';
+
+export default test({});
diff --git a/packages/svelte/tests/server-side-rendering/samples/input-default-value/_expected.html b/packages/svelte/tests/server-side-rendering/samples/input-default-value/_expected.html
new file mode 100644
index 0000000000..87635c9545
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/input-default-value/_expected.html
@@ -0,0 +1,6 @@
+<input value="hello" />
+<input type="checkbox" checked />
+<input value="spread" checked />
+<input value="" />
+<input value="" />
+<input value="" />
diff --git a/packages/svelte/tests/server-side-rendering/samples/input-default-value/main.svelte b/packages/svelte/tests/server-side-rendering/samples/input-default-value/main.svelte
new file mode 100644
index 0000000000..e1ad517850
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/input-default-value/main.svelte
@@ -0,0 +1,10 @@
+<script>
+	const props = { defaultValue: 'spread', defaultChecked: true };
+</script>
+
+<input defaultValue="hello" />
+<input type="checkbox" defaultChecked />
+<input {...props} />
+<input {...props} value="" checked={false} />
+<input value="" checked={false} {...props} />
+<input {...props} {...{ VALUE: '', CHECKED: false }} />

From 9d91a40fafcb126b857384fc39219d44877df631 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Mon, 31 Aug 2026 16:23:42 +0200
Subject: [PATCH 218/222] chore: bump packages (#18752)

esrap bump ensures a bugfix, devalue silences vulnerability reports
---
 packages/svelte/package.json              |  12 +-
 packages/svelte/src/compiler/utils/ast.js |   7 +-
 packages/svelte/src/internal/types.d.ts   |   6 +
 pnpm-lock.yaml                            | 460 ++++------------------
 4 files changed, 94 insertions(+), 391 deletions(-)

diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 73261b2864..53e5516bf6 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -171,17 +171,17 @@
     "web-features": "^3.29.0"
   },
   "dependencies": {
-    "@jridgewell/remapping": "^2.3.4",
-    "@jridgewell/sourcemap-codec": "^1.5.0",
-    "@sveltejs/acorn-typescript": "^1.0.10",
-    "@types/estree": "^1.0.5",
+    "@jridgewell/remapping": "^2.3.5",
+    "@jridgewell/sourcemap-codec": "^1.6.0",
+    "@sveltejs/acorn-typescript": "^1.0.13",
+    "@types/estree": "^1.0.9",
     "acorn": "^8.18.0",
     "aria-query": "5.3.1",
     "axobject-query": "^4.1.0",
     "clsx": "^2.1.1",
-    "devalue": "^5.8.1",
+    "devalue": "^5.9.2",
     "esm-env": "^1.2.1",
-    "esrap": "^2.2.12",
+    "esrap": "^2.3.6",
     "is-reference": "^3.0.3",
     "locate-character": "^3.0.0",
     "magic-string": "^0.30.11",
diff --git a/packages/svelte/src/compiler/utils/ast.js b/packages/svelte/src/compiler/utils/ast.js
index 75aadd905b..927674bd18 100644
--- a/packages/svelte/src/compiler/utils/ast.js
+++ b/packages/svelte/src/compiler/utils/ast.js
@@ -286,7 +286,7 @@ function _extract_paths(paths, inserts, param, expression, update_expression, ha
 					const props = [];
 
 					for (const p of param.properties) {
-						if (p.type === 'Property' && p.key.type !== 'PrivateIdentifier') {
+						if (p.type === 'Property') {
 							if (p.key.type === 'Identifier' && !p.computed) {
 								props.push(b.literal(p.key.name));
 							} else if (p.key.type === 'Literal') {
@@ -548,10 +548,7 @@ export function is_expression_async(expression) {
 				if (property.type === 'SpreadElement') {
 					return is_expression_async(property.argument);
 				} else if (property.type === 'Property') {
-					return (
-						(property.key.type !== 'PrivateIdentifier' && is_expression_async(property.key)) ||
-						is_expression_async(property.value)
-					);
+					return is_expression_async(property.key) || is_expression_async(property.value);
 				}
 			});
 		}
diff --git a/packages/svelte/src/internal/types.d.ts b/packages/svelte/src/internal/types.d.ts
index 12b2e5d4fb..2f9ff8d75b 100644
--- a/packages/svelte/src/internal/types.d.ts
+++ b/packages/svelte/src/internal/types.d.ts
@@ -1,2 +1,8 @@
 /** Anything except a function */
 export type NotFunction<T> = T extends Function ? never : T;
+
+declare global {
+	// @ts-ignore devalue has it in its types, but it's not part of the standard lib at the version our runtime is.
+	// We're not actually doing anything with it so we silence the error this ay
+	type Float16Array = any;
+}
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index f9897fb4b4..e7fee7b592 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -69,17 +69,17 @@ importers:
   packages/svelte:
     dependencies:
       '@jridgewell/remapping':
-        specifier: ^2.3.4
-        version: 2.3.4
+        specifier: ^2.3.5
+        version: 2.3.5
       '@jridgewell/sourcemap-codec':
-        specifier: ^1.5.0
-        version: 1.5.0
+        specifier: ^1.6.0
+        version: 1.6.0
       '@sveltejs/acorn-typescript':
-        specifier: ^1.0.10
-        version: 1.0.10(acorn@8.18.0)
+        specifier: ^1.0.13
+        version: 1.0.13(acorn@8.18.0)
       '@types/estree':
-        specifier: ^1.0.5
-        version: 1.0.8
+        specifier: ^1.0.9
+        version: 1.0.9
       acorn:
         specifier: ^8.18.0
         version: 8.18.0
@@ -93,14 +93,14 @@ importers:
         specifier: ^2.1.1
         version: 2.1.1
       devalue:
-        specifier: ^5.8.1
-        version: 5.8.1
+        specifier: ^5.9.2
+        version: 5.9.2
       esm-env:
         specifier: ^1.2.1
         version: 1.2.1
       esrap:
-        specifier: ^2.2.12
-        version: 2.2.12(@typescript-eslint/types@8.59.4)
+        specifier: ^2.3.6
+        version: 2.3.6(@typescript-eslint/types@8.59.4)
       is-reference:
         specifier: ^3.0.3
         version: 3.0.3
@@ -109,7 +109,7 @@ importers:
         version: 3.0.0
       magic-string:
         specifier: ^0.30.11
-        version: 0.30.17
+        version: 0.30.21
       zimmerframe:
         specifier: ^1.1.2
         version: 1.1.2
@@ -122,16 +122,16 @@ importers:
         version: 1.62.1
       '@rollup/plugin-commonjs':
         specifier: ^28.0.1
-        version: 28.0.1(rollup@4.60.1)
+        version: 28.0.1(rollup@4.62.2)
       '@rollup/plugin-node-resolve':
         specifier: ^15.3.0
-        version: 15.3.0(rollup@4.60.1)
+        version: 15.3.0(rollup@4.62.2)
       '@rollup/plugin-terser':
         specifier: ^0.4.4
-        version: 0.4.4(rollup@4.60.1)
+        version: 0.4.4(rollup@4.62.2)
       '@rollup/plugin-virtual':
         specifier: ^3.0.2
-        version: 3.0.2(rollup@4.60.1)
+        version: 3.0.2(rollup@4.62.2)
       '@types/aria-query':
         specifier: ^5.0.4
         version: 5.0.4
@@ -152,13 +152,13 @@ importers:
         version: 0.28.1
       rollup:
         specifier: ^4.59.0
-        version: 4.60.1
+        version: 4.62.2
       source-map:
         specifier: ^0.7.4
         version: 0.7.4
       tinyglobby:
         specifier: ^0.2.12
-        version: 0.2.15
+        version: 0.2.17
       typescript:
         specifier: ^5.5.4
         version: 5.5.4
@@ -185,7 +185,7 @@ importers:
         version: link:../../packages/svelte
       tinyglobby:
         specifier: ^0.2.12
-        version: 0.2.15
+        version: 0.2.17
       vite:
         specifier: ^7.3.5
         version: 7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
@@ -682,8 +682,8 @@ packages:
     resolution: {integrity: sha512-IzL8ZoEDIBRWEzlCcRhOaCupYyN5gdIK+Q6fbFdPDg6HqX6jpkItn7DFIpW9LQzXG6Df9sA7+OKnq0qlz/GaQg==}
     engines: {node: '>=6.0.0'}
 
-  '@jridgewell/remapping@2.3.4':
-    resolution: {integrity: sha512-aG+WvAz17rhbzhKNkSeMLgbkPPK82ovXdONvmucbGhUqcroRFLLVhoGAk4xEI17gHpXgNX3sr0/B1ybRUsbEWw==}
+  '@jridgewell/remapping@2.3.5':
+    resolution: {integrity: sha512-LI9u/+laYG4Ds1TDKSJW2YPrIlcVYOwi2fUC6xB43lueCjgxV4lffOCZCtYFiH6TNOX+tQKXx97T4IKHbhyHEQ==}
 
   '@jridgewell/resolve-uri@3.1.1':
     resolution: {integrity: sha512-dSYZh7HhCDtCKm4QakX0xFpsRDqjjtZf/kjI/v3T3Nwt5r8/qz/M19F9ySyOqU94SXBmeG9ttTul+YnR4LOxFA==}
@@ -696,11 +696,8 @@ packages:
   '@jridgewell/source-map@0.3.6':
     resolution: {integrity: sha512-1ZJTZebgqllO79ue2bm3rIGud/bOe0pP5BjSRCRxxYkEZS8STV7zN84UBbiYu7jy+eCKSnVIUgoWWE/tt+shMQ==}
 
-  '@jridgewell/sourcemap-codec@1.5.0':
-    resolution: {integrity: sha512-gv3ZRaISU3fjPAgNsriBRqGWQL6quFx04YMPW/zD8XMLsU32mhCCbfbO6KZFLjvYpCZ8zyDEgqsgf+PwPaM7GQ==}
-
-  '@jridgewell/sourcemap-codec@1.5.5':
-    resolution: {integrity: sha512-cYQ9310grqxueWbl+WuIUIaiUaDcj7WOq5fVhEljNVgRfOUhY9fy2zTvfoqWsnebh8Sl70VScFbICvJnLKB0Og==}
+  '@jridgewell/sourcemap-codec@1.6.0':
+    resolution: {integrity: sha512-T7jf+5zgsZHwNJ4lvQ7/aezbyk0nNX+zJVWpmHA7VYsEx7a7qr5Rg5IbtJFqkgze5Y2sruq1RUY8Q837Od7iFw==}
 
   '@jridgewell/trace-mapping@0.3.31':
     resolution: {integrity: sha512-zzNR+SdQSDJzc8joaeP8QQoCQr8NuYx2dIIytl1QeBEZHJ9uW6hebsrYgbz8hJwUQao3TWCMtmfV8Nu1twOLAw==}
@@ -776,277 +773,139 @@ packages:
       rollup:
         optional: true
 
-  '@rollup/rollup-android-arm-eabi@4.60.1':
-    resolution: {integrity: sha512-d6FinEBLdIiK+1uACUttJKfgZREXrF0Qc2SmLII7W2AD8FfiZ9Wjd+rD/iRuf5s5dWrr1GgwXCvPqOuDquOowA==}
-    cpu: [arm]
-    os: [android]
-
   '@rollup/rollup-android-arm-eabi@4.62.2':
     resolution: {integrity: sha512-6o7ZLZK+BeenkZCFNDXqpbjw9bD6nuWonvS/lwQJp7NoVVxm6p3qE7qQ5jGuBjiFsgvqjD8mZAU5oWxTmbOeOg==}
     cpu: [arm]
     os: [android]
 
-  '@rollup/rollup-android-arm64@4.60.1':
-    resolution: {integrity: sha512-YjG/EwIDvvYI1YvYbHvDz/BYHtkY4ygUIXHnTdLhG+hKIQFBiosfWiACWortsKPKU/+dUwQQCKQM3qrDe8c9BA==}
-    cpu: [arm64]
-    os: [android]
-
   '@rollup/rollup-android-arm64@4.62.2':
     resolution: {integrity: sha512-BaH7BllCACHoH1LguOU56UItGfUWjujlO65kS9LAodViaN4bwIKd7oeW/ZHJ/4ljr/7MIiENnNy3HJ0zXv8Zkw==}
     cpu: [arm64]
     os: [android]
 
-  '@rollup/rollup-darwin-arm64@4.60.1':
-    resolution: {integrity: sha512-mjCpF7GmkRtSJwon+Rq1N8+pI+8l7w5g9Z3vWj4T7abguC4Czwi3Yu/pFaLvA3TTeMVjnu3ctigusqWUfjZzvw==}
-    cpu: [arm64]
-    os: [darwin]
-
   '@rollup/rollup-darwin-arm64@4.62.2':
     resolution: {integrity: sha512-v39RCCvj4He82I9sFmk+M1VZ0PLM9sfsLVikjfx2hYBNALhrrOR2D3JjQA6AhlaSOgcR+RzrKY7e1+bT6SUO/A==}
     cpu: [arm64]
     os: [darwin]
 
-  '@rollup/rollup-darwin-x64@4.60.1':
-    resolution: {integrity: sha512-haZ7hJ1JT4e9hqkoT9R/19XW2QKqjfJVv+i5AGg57S+nLk9lQnJ1F/eZloRO3o9Scy9CM3wQ9l+dkXtcBgN5Ew==}
-    cpu: [x64]
-    os: [darwin]
-
   '@rollup/rollup-darwin-x64@4.62.2':
     resolution: {integrity: sha512-yl0y2vq3S3lHeuXhEdss6TWfKW8vkujImO12tn4ZkG/4oghr09LvdYm2RElVjokTQiUvDUGXLGsYeLqUMCKpGA==}
     cpu: [x64]
     os: [darwin]
 
-  '@rollup/rollup-freebsd-arm64@4.60.1':
-    resolution: {integrity: sha512-czw90wpQq3ZsAVBlinZjAYTKduOjTywlG7fEeWKUA7oCmpA8xdTkxZZlwNJKWqILlq0wehoZcJYfBvOyhPTQ6w==}
-    cpu: [arm64]
-    os: [freebsd]
-
   '@rollup/rollup-freebsd-arm64@4.62.2':
     resolution: {integrity: sha512-tT4pvt4qXD+vEoezupCWi+a1F0vvDiksiHc+PxRlYTOH1I6/X4id9jPxTP+Fg+545euaFT1jJVs4CEdHZAU1vw==}
     cpu: [arm64]
     os: [freebsd]
 
-  '@rollup/rollup-freebsd-x64@4.60.1':
-    resolution: {integrity: sha512-KVB2rqsxTHuBtfOeySEyzEOB7ltlB/ux38iu2rBQzkjbwRVlkhAGIEDiiYnO2kFOkJp+Z7pUXKyrRRFuFUKt+g==}
-    cpu: [x64]
-    os: [freebsd]
-
   '@rollup/rollup-freebsd-x64@4.62.2':
     resolution: {integrity: sha512-6nU5F2wCW+qvCBhTn1pdIU3bzsIoF7EUwsCDRxilWGprQR6yd508YnH9+OKFCwpfS8pjZqDUmnCAr7exax0XCg==}
     cpu: [x64]
     os: [freebsd]
 
-  '@rollup/rollup-linux-arm-gnueabihf@4.60.1':
-    resolution: {integrity: sha512-L+34Qqil+v5uC0zEubW7uByo78WOCIrBvci69E7sFASRl0X7b/MB6Cqd1lky/CtcSVTydWa2WZwFuWexjS5o6g==}
-    cpu: [arm]
-    os: [linux]
-    libc: [glibc]
-
   '@rollup/rollup-linux-arm-gnueabihf@4.62.2':
     resolution: {integrity: sha512-n1GJHPOvpIfhi3TmrCeh6S6URt9BFCt0KQE3qvexyGCTAKpR4Lg+eWvNZEqu7epxwus/8ElT3hacYEucm49SZg==}
     cpu: [arm]
     os: [linux]
     libc: [glibc]
 
-  '@rollup/rollup-linux-arm-musleabihf@4.60.1':
-    resolution: {integrity: sha512-n83O8rt4v34hgFzlkb1ycniJh7IR5RCIqt6mz1VRJD6pmhRi0CXdmfnLu9dIUS6buzh60IvACM842Ffb3xd6Gg==}
-    cpu: [arm]
-    os: [linux]
-    libc: [musl]
-
   '@rollup/rollup-linux-arm-musleabihf@4.62.2':
     resolution: {integrity: sha512-JqgflS8wEB+UXV/vS1RpRbifGBeN4D5lz8D8oOFbFZw4vedvdOgCFAjfBmIMdW3yL10XpQQ0Ambepw6MXrhOnA==}
     cpu: [arm]
     os: [linux]
     libc: [musl]
 
-  '@rollup/rollup-linux-arm64-gnu@4.60.1':
-    resolution: {integrity: sha512-Nql7sTeAzhTAja3QXeAI48+/+GjBJ+QmAH13snn0AJSNL50JsDqotyudHyMbO2RbJkskbMbFJfIJKWA6R1LCJQ==}
-    cpu: [arm64]
-    os: [linux]
-    libc: [glibc]
-
   '@rollup/rollup-linux-arm64-gnu@4.62.2':
     resolution: {integrity: sha512-wnFJkogWvN4jm/hQRF2UBaeUmk20j5+DmHvoyWii2b8HJDyvz1MF2OU/6ynXt2KR63rbZLWkFpoytpdc/yBuSA==}
     cpu: [arm64]
     os: [linux]
     libc: [glibc]
 
-  '@rollup/rollup-linux-arm64-musl@4.60.1':
-    resolution: {integrity: sha512-+pUymDhd0ys9GcKZPPWlFiZ67sTWV5UU6zOJat02M1+PiuSGDziyRuI/pPue3hoUwm2uGfxdL+trT6Z9rxnlMA==}
-    cpu: [arm64]
-    os: [linux]
-    libc: [musl]
-
   '@rollup/rollup-linux-arm64-musl@4.62.2':
     resolution: {integrity: sha512-HVu2bp0zhvJ8xHEV9+UUs7S90VadmBSY3LcIMvozbPo4AuMGDWlz3ymHLHZPX4hR67TKTt8Qp5PJ5RBg/i+RMQ==}
     cpu: [arm64]
     os: [linux]
     libc: [musl]
 
-  '@rollup/rollup-linux-loong64-gnu@4.60.1':
-    resolution: {integrity: sha512-VSvgvQeIcsEvY4bKDHEDWcpW4Yw7BtlKG1GUT4FzBUlEKQK0rWHYBqQt6Fm2taXS+1bXvJT6kICu5ZwqKCnvlQ==}
-    cpu: [loong64]
-    os: [linux]
-    libc: [glibc]
-
   '@rollup/rollup-linux-loong64-gnu@4.62.2':
     resolution: {integrity: sha512-mQqqAV8QaoSgr9I2fKDLY2BAVvmKjWoGiu/cSYQonsLvtqwEn1E4QYfnCOcp5zoEqNhsDYin1s6jx/VJmrxlZg==}
     cpu: [loong64]
     os: [linux]
     libc: [glibc]
 
-  '@rollup/rollup-linux-loong64-musl@4.60.1':
-    resolution: {integrity: sha512-4LqhUomJqwe641gsPp6xLfhqWMbQV04KtPp7/dIp0nzPxAkNY1AbwL5W0MQpcalLYk07vaW9Kp1PBhdpZYYcEw==}
-    cpu: [loong64]
-    os: [linux]
-    libc: [musl]
-
   '@rollup/rollup-linux-loong64-musl@4.62.2':
     resolution: {integrity: sha512-IxKLoxCQ2IWi6bT2akyDUBGsOImDKB+sPp4EsTmwFQ/fMwpCKm8uLSSgP/Kx/QYUgKis6SEZ5/Nlhup0DIA0PQ==}
     cpu: [loong64]
     os: [linux]
     libc: [musl]
 
-  '@rollup/rollup-linux-ppc64-gnu@4.60.1':
-    resolution: {integrity: sha512-tLQQ9aPvkBxOc/EUT6j3pyeMD6Hb8QF2BTBnCQWP/uu1lhc9AIrIjKnLYMEroIz/JvtGYgI9dF3AxHZNaEH0rw==}
-    cpu: [ppc64]
-    os: [linux]
-    libc: [glibc]
-
   '@rollup/rollup-linux-ppc64-gnu@4.62.2':
     resolution: {integrity: sha512-Mk5ha2RQSgyFfmYYLkBpPnUk8D8FriBxesO1u9O75X0mHgXL1UQcH5Itl2lurWL2tj0RxV9b9tJgipac0hRY9A==}
     cpu: [ppc64]
     os: [linux]
     libc: [glibc]
 
-  '@rollup/rollup-linux-ppc64-musl@4.60.1':
-    resolution: {integrity: sha512-RMxFhJwc9fSXP6PqmAz4cbv3kAyvD1etJFjTx4ONqFP9DkTkXsAMU4v3Vyc5BgzC+anz7nS/9tp4obsKfqkDHg==}
-    cpu: [ppc64]
-    os: [linux]
-    libc: [musl]
-
   '@rollup/rollup-linux-ppc64-musl@4.62.2':
     resolution: {integrity: sha512-CjvEnqJL/0/TQ3TXX3OPIJ/kmBellrWd4heXUmHeJlTnmwjKpSJzoehLaL6Xk0ZnMHBu9dZuFADNOrtjF4v+2w==}
     cpu: [ppc64]
     os: [linux]
     libc: [musl]
 
-  '@rollup/rollup-linux-riscv64-gnu@4.60.1':
-    resolution: {integrity: sha512-QKgFl+Yc1eEk6MmOBfRHYF6lTxiiiV3/z/BRrbSiW2I7AFTXoBFvdMEyglohPj//2mZS4hDOqeB0H1ACh3sBbg==}
-    cpu: [riscv64]
-    os: [linux]
-    libc: [glibc]
-
   '@rollup/rollup-linux-riscv64-gnu@4.62.2':
     resolution: {integrity: sha512-1SiZbzwdkaDURsew/tSOrooKiYy7EQGT6m8ufavAi9NEyQb/6VuIxFXAL1fqa4iZe3g4NbNk4P7J32z2tw5Mgg==}
     cpu: [riscv64]
     os: [linux]
     libc: [glibc]
 
-  '@rollup/rollup-linux-riscv64-musl@4.60.1':
-    resolution: {integrity: sha512-RAjXjP/8c6ZtzatZcA1RaQr6O1TRhzC+adn8YZDnChliZHviqIjmvFwHcxi4JKPSDAt6Uhf/7vqcBzQJy0PDJg==}
-    cpu: [riscv64]
-    os: [linux]
-    libc: [musl]
-
   '@rollup/rollup-linux-riscv64-musl@4.62.2':
     resolution: {integrity: sha512-nQts12zJ3NQRoE6uYljOH89v7szzLDvG2JD/vsX+vGXU8w/At1GowTZ5/7qeFQ8m7L55rpR8Okugnuo5bgjy2Q==}
     cpu: [riscv64]
     os: [linux]
     libc: [musl]
 
-  '@rollup/rollup-linux-s390x-gnu@4.60.1':
-    resolution: {integrity: sha512-wcuocpaOlaL1COBYiA89O6yfjlp3RwKDeTIA0hM7OpmhR1Bjo9j31G1uQVpDlTvwxGn2nQs65fBFL5UFd76FcQ==}
-    cpu: [s390x]
-    os: [linux]
-    libc: [glibc]
-
   '@rollup/rollup-linux-s390x-gnu@4.62.2':
     resolution: {integrity: sha512-E9/ll019jhPIJgpzfZoIkBGhcz+kKNgVWYRY0zr9srBdPPFVpvOKW8VaJKUbeK+eZXyQF9ltME+Kk6affeaPgg==}
     cpu: [s390x]
     os: [linux]
     libc: [glibc]
 
-  '@rollup/rollup-linux-x64-gnu@4.60.1':
-    resolution: {integrity: sha512-77PpsFQUCOiZR9+LQEFg9GClyfkNXj1MP6wRnzYs0EeWbPcHs02AXu4xuUbM1zhwn3wqaizle3AEYg5aeoohhg==}
-    cpu: [x64]
-    os: [linux]
-    libc: [glibc]
-
   '@rollup/rollup-linux-x64-gnu@4.62.2':
     resolution: {integrity: sha512-5BqxR/pshjey51iliyzTD5Xi3EN0aLmQ2lZ3lvefVV9c82BvrLo2/6OT55iifpWBufs6kdwWbuOKS841DrmK9A==}
     cpu: [x64]
     os: [linux]
     libc: [glibc]
 
-  '@rollup/rollup-linux-x64-musl@4.60.1':
-    resolution: {integrity: sha512-5cIATbk5vynAjqqmyBjlciMJl1+R/CwX9oLk/EyiFXDWd95KpHdrOJT//rnUl4cUcskrd0jCCw3wpZnhIHdD9w==}
-    cpu: [x64]
-    os: [linux]
-    libc: [musl]
-
   '@rollup/rollup-linux-x64-musl@4.62.2':
     resolution: {integrity: sha512-uNN83XxQrRAh/w0/pmAfibcwyb6YWt4gP+dpnQKPVJshAloQ785ii8CT8ZCIxkGg9opVsvAlGhFitSm6D1Jjpg==}
     cpu: [x64]
     os: [linux]
     libc: [musl]
 
-  '@rollup/rollup-openbsd-x64@4.60.1':
-    resolution: {integrity: sha512-cl0w09WsCi17mcmWqqglez9Gk8isgeWvoUZ3WiJFYSR3zjBQc2J5/ihSjpl+VLjPqjQ/1hJRcqBfLjssREQILw==}
-    cpu: [x64]
-    os: [openbsd]
-
   '@rollup/rollup-openbsd-x64@4.62.2':
     resolution: {integrity: sha512-srjEIxSH3LRnJN6THczDHWQplqEMFiAJrTab0msUryh9kwNpkICf3Ea6q6MN/2cZwRFUNx5w+h6Hpi4QuHS6Zg==}
     cpu: [x64]
     os: [openbsd]
 
-  '@rollup/rollup-openharmony-arm64@4.60.1':
-    resolution: {integrity: sha512-4Cv23ZrONRbNtbZa37mLSueXUCtN7MXccChtKpUnQNgF010rjrjfHx3QxkS2PI7LqGT5xXyYs1a7LbzAwT0iCA==}
-    cpu: [arm64]
-    os: [openharmony]
-
   '@rollup/rollup-openharmony-arm64@4.62.2':
     resolution: {integrity: sha512-8hOJnxgbyObnCm5AlRA3A931xX19xq80RjVTKgJOvEKWqJruP/Uf12IbAOaDjjEXYRewwHLfmF0YRIdK3OwKWA==}
     cpu: [arm64]
     os: [openharmony]
 
-  '@rollup/rollup-win32-arm64-msvc@4.60.1':
-    resolution: {integrity: sha512-i1okWYkA4FJICtr7KpYzFpRTHgy5jdDbZiWfvny21iIKky5YExiDXP+zbXzm3dUcFpkEeYNHgQ5fuG236JPq0g==}
-    cpu: [arm64]
-    os: [win32]
-
   '@rollup/rollup-win32-arm64-msvc@4.62.2':
     resolution: {integrity: sha512-mmF4AY1i0hG/bLWUctUq59gtmgaSIRa3cu/A3JFRp/sCNEme2bgDEiDS22P9FbnJB8NJNF4jPJiSP5RHQpUTDg==}
     cpu: [arm64]
     os: [win32]
 
-  '@rollup/rollup-win32-ia32-msvc@4.60.1':
-    resolution: {integrity: sha512-u09m3CuwLzShA0EYKMNiFgcjjzwqtUMLmuCJLeZWjjOYA3IT2Di09KaxGBTP9xVztWyIWjVdsB2E9goMjZvTQg==}
-    cpu: [ia32]
-    os: [win32]
-
   '@rollup/rollup-win32-ia32-msvc@4.62.2':
     resolution: {integrity: sha512-DZgkknc6jhHrk46V25vbAM0zZkyP0nSDkJB8/dRkLTxv470dOmWDqGoEJl/9A0dFfS7yE3REOwNDxpHwSLSt0Q==}
     cpu: [ia32]
     os: [win32]
 
-  '@rollup/rollup-win32-x64-gnu@4.60.1':
-    resolution: {integrity: sha512-k+600V9Zl1CM7eZxJgMyTUzmrmhB/0XZnF4pRypKAlAgxmedUA+1v9R+XOFv56W4SlHEzfeMtzujLJD22Uz5zg==}
-    cpu: [x64]
-    os: [win32]
-
   '@rollup/rollup-win32-x64-gnu@4.62.2':
     resolution: {integrity: sha512-T6xr6ucWSFto+VGajA8YH26LdpHRuP4YLHEKAtCWvJDOlnmWcDZVCI2Jmjr+IFHDlt2zRaTAKE4tfjTaWLgJBg==}
     cpu: [x64]
     os: [win32]
 
-  '@rollup/rollup-win32-x64-msvc@4.60.1':
-    resolution: {integrity: sha512-lWMnixq/QzxyhTV6NjQJ4SFo1J6PvOX8vUx5Wb4bBPsEb+8xZ89Bz6kOXpfXj9ak9AHTQVQzlgzBEc1SyM27xQ==}
-    cpu: [x64]
-    os: [win32]
-
   '@rollup/rollup-win32-x64-msvc@4.62.2':
     resolution: {integrity: sha512-BfzEnDJOt9T8M989/lA37EcJgat01wLRnoi5dQf3QzOH7jzpqTAzdDbVfRljVr5r+jzKqpbHeyOfAaXxAd0PAA==}
     cpu: [x64]
@@ -1061,8 +920,8 @@ packages:
     peerDependencies:
       eslint: '>=8.40.0'
 
-  '@sveltejs/acorn-typescript@1.0.10':
-    resolution: {integrity: sha512-4WfKk68eTih+MiJD4fSbxN7E8kVBmTMPWHUPYjvl2N0rMs53YLTT8/YjKU5Dtnz5LqDjl7LEw4U7lXR2W3J5WA==}
+  '@sveltejs/acorn-typescript@1.0.13':
+    resolution: {integrity: sha512-wgKggnhZVL9Bfx1OaKKTrYY9BFRk6C8UAkQNUcIv1+llzYrIqy+RZm5HPKzn0NpEBvTVhTqB4kQyllZywsRBRQ==}
     peerDependencies:
       acorn: ^8.9.0
 
@@ -1108,9 +967,6 @@ packages:
   '@types/esrecurse@4.3.1':
     resolution: {integrity: sha512-xJBAbDifo5hpffDBuHl0Y8ywswbiAp/Wi7Y/GtAgSlZyIABppyurxVueOPE8LUQOxdlgi6Zqce7uoEpqNTeiUw==}
 
-  '@types/estree@1.0.8':
-    resolution: {integrity: sha512-dWHzHa2WqEXI/O1E9OjrocMTKJl2mSrEolh1Iomrv6U+JuNwaHXsXx9bLu5gG7BUWFIN0skIQJQ/L1rIex4X6w==}
-
   '@types/estree@1.0.9':
     resolution: {integrity: sha512-GhdPgy1el4/ImP05X05Uw4cw2/M93BCUmnEvWZNStlCzEKME4Fkk+YpoA5OiHNQmoS7Cafb8Xa3Pya8m1Qrzeg==}
 
@@ -1426,8 +1282,8 @@ packages:
     engines: {node: '>=0.10'}
     hasBin: true
 
-  devalue@5.8.1:
-    resolution: {integrity: sha512-4CXDYRBGqN+57wVJkuXBYmpAVUSg3L6JAQa/DFqm238G73E1wuyc/JhGQJzN7vUf/CMphYau2zXbfWzDR5aTEw==}
+  devalue@5.9.2:
+    resolution: {integrity: sha512-po4PAY5c53tw5XMocSnf8A/5OHhbbUftpr93aEN6BBoAdntUmK7vu7wOATqvt7cXO7m1Cl4gMVn6p7n6n4mj0w==}
 
   dir-glob@3.0.1:
     resolution: {integrity: sha512-WkrWp9GR4KXfKGYzOLmTuGVi1UWFfws377n9cc55/tb6DuqyF6pcQ5AbiHEshaDpY9v6oaSr2XCDidGmMwdzIA==}
@@ -1564,8 +1420,8 @@ packages:
     resolution: {integrity: sha512-Ap6G0WQwcU/LHsvLwON1fAQX9Zp0A2Y6Y/cJBl9r/JbW90Zyg4/zbG6zzKa2OTALELarYHmKu0GhpM5EO+7T0g==}
     engines: {node: '>=0.10'}
 
-  esrap@2.2.12:
-    resolution: {integrity: sha512-On0QbLyaiAkVC4eXtgnXK9Kh2opit+3rcUSOc45DqJ2s/X2eXAHsGOKRSJ6IDagQEW5vPyivANfXUiqgXC67Rw==}
+  esrap@2.3.6:
+    resolution: {integrity: sha512-yc0OC12UjPqLoc+fe+v5GNs4TOjAigUw3sTikfC+xeBPGUw7gDRz3DtYaqEhxyMVJojcSWJw7jT0QWR+CbuE/A==}
     peerDependencies:
       '@typescript-eslint/types': ^8.2.0
     peerDependenciesMeta:
@@ -1947,9 +1803,6 @@ packages:
   lodash.startcase@4.4.0:
     resolution: {integrity: sha512-+WKqsK294HMSc2jEbNgpHpd0JfIBhp7rEV4aqXWqFr6AlXov+SlcgB1Fv01y2kGe3Gc8nMW7VA0SrGuSkRfIEg==}
 
-  magic-string@0.30.17:
-    resolution: {integrity: sha512-sNPKHvyjVf7gyjwS4xGTaW/mCnF8wnjtifKBEhxfZ7E/S8tQ0rssrwGNn6q8JH/ohItJfSQp9mBtQYuTlH5QnA==}
-
   magic-string@0.30.21:
     resolution: {integrity: sha512-vd2F4YUyEXKGcLHoq+TEyCjxueSeHnFxyyjNp80yg0XV4vUhnDer/lvvlqM/arB5bXQN5K2/3oinyCRyx8T2CQ==}
 
@@ -1995,11 +1848,6 @@ packages:
   ms@2.1.3:
     resolution: {integrity: sha512-6FlzubTLZG3J2a/NVCAleEhjzq5oxgHyaCU9yYXvcLsvoVaHJq/s5xXI6/XXP6tz7R9xAOtHnSO/tXtF3WRTlA==}
 
-  nanoid@3.3.11:
-    resolution: {integrity: sha512-N8SpfPUnUp1bK+PMYW8qSWdl9U+wwNWI4QKxOYDy9JAro3WMX7p2OeVRF9v+347pnakNevPmiHhNmZ2HbFA76w==}
-    engines: {node: ^10 || ^12 || ^13.7 || ^14 || >=15.0.1}
-    hasBin: true
-
   nanoid@3.3.13:
     resolution: {integrity: sha512-sPdqC6ByMVVGvF1ynvvMo0/o+oD1VX7DaHhijt1bFgjvBkHBib4t49GoNDhf2NDta4oeUNlaGbSt5K7qjZ955Q==}
     engines: {node: ^10 || ^12 || ^13.7 || ^14 || >=15.0.1}
@@ -2148,10 +1996,6 @@ packages:
     resolution: {integrity: sha512-FfR8sjd4em2T6fb3I2MwAJU7HWVMr9zba+enmQeeWFfCbm+UOC/0X4DS8XtpUTMwWMGbjKYP7xjfNekzyGmB3A==}
     engines: {node: ^10 || ^12 || >=14}
 
-  postcss@8.5.9:
-    resolution: {integrity: sha512-7a70Nsot+EMX9fFU3064K/kdHWZqGVY+BADLyXc8Dfv+mTLLVl6JzJpPaCZ2kQL9gIJvKXSLMHhqdRRjwQeFtw==}
-    engines: {node: ^10 || ^12 || >=14}
-
   prelude-ls@1.2.1:
     resolution: {integrity: sha512-vkcDPrRZo1QZLbn5RLGPpg/WmIQ65qoWWhcGKf/b5eplkkarX0m9z8ppCat4mlOqUsWpyNuYgO3VRyrYHSzX5g==}
     engines: {node: '>= 0.8.0'}
@@ -2212,11 +2056,6 @@ packages:
     resolution: {integrity: sha512-U9nH88a3fc/ekCF1l0/UP1IosiuIjyTh7hBvXVMHYgVcfGvt897Xguj2UOLDeI5BG2m7/uwyaLVT6fbtCwTyzw==}
     engines: {iojs: '>=1.0.0', node: '>=0.10.0'}
 
-  rollup@4.60.1:
-    resolution: {integrity: sha512-VmtB2rFU/GroZ4oL8+ZqXgSA38O6GR8KSIvWmEFv63pQ0G6KaBH9s07PO8XTXP4vI+3UJUEypOfjkGfmSBBR0w==}
-    engines: {node: '>=18.0.0', npm: '>=8.0.0'}
-    hasBin: true
-
   rollup@4.62.2:
     resolution: {integrity: sha512-RFnrW4lhXA3s3eqHDZvN654g8OTjzRfqpIRJYczCGB6HzphckVAi/Qh4tbPUbRuDi7s1Llv8g/NspLkttY3gTA==}
     engines: {node: '>=18.0.0', npm: '>=8.0.0'}
@@ -2251,11 +2090,6 @@ packages:
     resolution: {integrity: sha512-xAg7SOnEhrm5zI3puOOKyy1OMcMlIJZYNJY7xLBwSze0UjhPLnWfj2GF2EpT0jmzaJKIWKHLsaSSajf35bcYnA==}
     engines: {node: '>=v12.22.7'}
 
-  semver@7.7.4:
-    resolution: {integrity: sha512-vFKC2IEtQnVhpT78h1Yp8wzwrf8CM+MzKMHGJZfBtzhZNycRFnXsHk6E5TxIkkMsgNS7mdX3AGB7x2QM2di4lA==}
-    engines: {node: '>=10'}
-    hasBin: true
-
   semver@7.8.5:
     resolution: {integrity: sha512-Y7/KDsb8LjooZpwaqGyulO6DQlksgCncchHGk+sZIY4SBvUocMBEFH5Ur1fI4dV+Jvl0w6cjvucaIi40puRioA==}
     engines: {node: '>=10'}
@@ -2365,10 +2199,6 @@ packages:
     resolution: {integrity: sha512-dAqSqE/RabpBKI8+h26GfLq6Vb3JVXs30XYQjdMjaj/c2tS8IYYMbIzP599KtRj7c57/wYApb3QjgRgXmrCukA==}
     engines: {node: '>=18'}
 
-  tinyglobby@0.2.15:
-    resolution: {integrity: sha512-j2Zq4NyQYG5XMST4cbs02Ak8iJUdxRM0XI5QyxXuZOzKOINmWurp3smXu3y5wDcJrptwpSjgXHzIQxR0omXljQ==}
-    engines: {node: '>=12.0.0'}
-
   tinyglobby@0.2.17:
     resolution: {integrity: sha512-wXR/dYpcqKmfWpEdZjiKJOwCNFndD0DMnrW/cYjVGttEkBfVgcLFHoNrlj47mjOVic9yyNu65alsgF4NQyTa2g==}
     engines: {node: '>=12.0.0'}
@@ -2682,7 +2512,7 @@ snapshots:
       outdent: 0.5.0
       prettier: 2.8.8
       resolve-from: 5.0.0
-      semver: 7.7.4
+      semver: 7.8.5
 
   '@changesets/assemble-release-plan@6.0.9':
     dependencies:
@@ -2691,7 +2521,7 @@ snapshots:
       '@changesets/should-skip-package': 0.1.2
       '@changesets/types': 6.1.0
       '@manypkg/get-packages': 1.1.3
-      semver: 7.7.4
+      semver: 7.8.5
 
   '@changesets/changelog-git@0.2.1':
     dependencies:
@@ -2729,7 +2559,7 @@ snapshots:
       package-manager-detector: 0.2.11
       picocolors: 1.1.1
       resolve-from: 5.0.0
-      semver: 7.7.4
+      semver: 7.8.5
       spawndamnit: 3.0.1
       term-size: 2.2.1
     transitivePeerDependencies:
@@ -2754,7 +2584,7 @@ snapshots:
       '@changesets/types': 6.1.0
       '@manypkg/get-packages': 1.1.3
       picocolors: 1.1.1
-      semver: 7.7.4
+      semver: 7.8.5
 
   '@changesets/get-github-info@1.0.0-next.4':
     dependencies:
@@ -3040,10 +2870,10 @@ snapshots:
   '@jridgewell/gen-mapping@0.3.5':
     dependencies:
       '@jridgewell/set-array': 1.2.1
-      '@jridgewell/sourcemap-codec': 1.5.5
+      '@jridgewell/sourcemap-codec': 1.6.0
       '@jridgewell/trace-mapping': 0.3.31
 
-  '@jridgewell/remapping@2.3.4':
+  '@jridgewell/remapping@2.3.5':
     dependencies:
       '@jridgewell/gen-mapping': 0.3.5
       '@jridgewell/trace-mapping': 0.3.31
@@ -3057,14 +2887,12 @@ snapshots:
       '@jridgewell/gen-mapping': 0.3.5
       '@jridgewell/trace-mapping': 0.3.31
 
-  '@jridgewell/sourcemap-codec@1.5.0': {}
-
-  '@jridgewell/sourcemap-codec@1.5.5': {}
+  '@jridgewell/sourcemap-codec@1.6.0': {}
 
   '@jridgewell/trace-mapping@0.3.31':
     dependencies:
       '@jridgewell/resolve-uri': 3.1.1
-      '@jridgewell/sourcemap-codec': 1.5.0
+      '@jridgewell/sourcemap-codec': 1.6.0
 
   '@manypkg/find-root@1.1.0':
     dependencies:
@@ -3100,195 +2928,120 @@ snapshots:
 
   '@polka/url@1.0.0-next.25': {}
 
-  '@rollup/plugin-commonjs@28.0.1(rollup@4.60.1)':
+  '@rollup/plugin-commonjs@28.0.1(rollup@4.62.2)':
     dependencies:
-      '@rollup/pluginutils': 5.1.0(rollup@4.60.1)
+      '@rollup/pluginutils': 5.1.0(rollup@4.62.2)
       commondir: 1.0.1
       estree-walker: 2.0.2
       fdir: 6.5.0(picomatch@4.0.4)
       is-reference: 1.2.1
-      magic-string: 0.30.17
+      magic-string: 0.30.21
       picomatch: 4.0.4
     optionalDependencies:
-      rollup: 4.60.1
+      rollup: 4.62.2
 
-  '@rollup/plugin-node-resolve@15.3.0(rollup@4.60.1)':
+  '@rollup/plugin-node-resolve@15.3.0(rollup@4.62.2)':
     dependencies:
-      '@rollup/pluginutils': 5.1.0(rollup@4.60.1)
+      '@rollup/pluginutils': 5.1.0(rollup@4.62.2)
       '@types/resolve': 1.20.2
       deepmerge: 4.3.1
       is-module: 1.0.0
       resolve: 1.22.8
     optionalDependencies:
-      rollup: 4.60.1
+      rollup: 4.62.2
 
-  '@rollup/plugin-terser@0.4.4(rollup@4.60.1)':
+  '@rollup/plugin-terser@0.4.4(rollup@4.62.2)':
     dependencies:
       serialize-javascript: 6.0.2
       smob: 1.4.1
       terser: 5.27.0
     optionalDependencies:
-      rollup: 4.60.1
+      rollup: 4.62.2
 
-  '@rollup/plugin-virtual@3.0.2(rollup@4.60.1)':
+  '@rollup/plugin-virtual@3.0.2(rollup@4.62.2)':
     optionalDependencies:
-      rollup: 4.60.1
+      rollup: 4.62.2
 
-  '@rollup/pluginutils@5.1.0(rollup@4.60.1)':
+  '@rollup/pluginutils@5.1.0(rollup@4.62.2)':
     dependencies:
-      '@types/estree': 1.0.8
+      '@types/estree': 1.0.9
       estree-walker: 2.0.2
       picomatch: 2.3.2
     optionalDependencies:
-      rollup: 4.60.1
-
-  '@rollup/rollup-android-arm-eabi@4.60.1':
-    optional: true
+      rollup: 4.62.2
 
   '@rollup/rollup-android-arm-eabi@4.62.2':
     optional: true
 
-  '@rollup/rollup-android-arm64@4.60.1':
-    optional: true
-
   '@rollup/rollup-android-arm64@4.62.2':
     optional: true
 
-  '@rollup/rollup-darwin-arm64@4.60.1':
-    optional: true
-
   '@rollup/rollup-darwin-arm64@4.62.2':
     optional: true
 
-  '@rollup/rollup-darwin-x64@4.60.1':
-    optional: true
-
   '@rollup/rollup-darwin-x64@4.62.2':
     optional: true
 
-  '@rollup/rollup-freebsd-arm64@4.60.1':
-    optional: true
-
   '@rollup/rollup-freebsd-arm64@4.62.2':
     optional: true
 
-  '@rollup/rollup-freebsd-x64@4.60.1':
-    optional: true
-
   '@rollup/rollup-freebsd-x64@4.62.2':
     optional: true
 
-  '@rollup/rollup-linux-arm-gnueabihf@4.60.1':
-    optional: true
-
   '@rollup/rollup-linux-arm-gnueabihf@4.62.2':
     optional: true
 
-  '@rollup/rollup-linux-arm-musleabihf@4.60.1':
-    optional: true
-
   '@rollup/rollup-linux-arm-musleabihf@4.62.2':
     optional: true
 
-  '@rollup/rollup-linux-arm64-gnu@4.60.1':
-    optional: true
-
   '@rollup/rollup-linux-arm64-gnu@4.62.2':
     optional: true
 
-  '@rollup/rollup-linux-arm64-musl@4.60.1':
-    optional: true
-
   '@rollup/rollup-linux-arm64-musl@4.62.2':
     optional: true
 
-  '@rollup/rollup-linux-loong64-gnu@4.60.1':
-    optional: true
-
   '@rollup/rollup-linux-loong64-gnu@4.62.2':
     optional: true
 
-  '@rollup/rollup-linux-loong64-musl@4.60.1':
-    optional: true
-
   '@rollup/rollup-linux-loong64-musl@4.62.2':
     optional: true
 
-  '@rollup/rollup-linux-ppc64-gnu@4.60.1':
-    optional: true
-
   '@rollup/rollup-linux-ppc64-gnu@4.62.2':
     optional: true
 
-  '@rollup/rollup-linux-ppc64-musl@4.60.1':
-    optional: true
-
   '@rollup/rollup-linux-ppc64-musl@4.62.2':
     optional: true
 
-  '@rollup/rollup-linux-riscv64-gnu@4.60.1':
-    optional: true
-
   '@rollup/rollup-linux-riscv64-gnu@4.62.2':
     optional: true
 
-  '@rollup/rollup-linux-riscv64-musl@4.60.1':
-    optional: true
-
   '@rollup/rollup-linux-riscv64-musl@4.62.2':
     optional: true
 
-  '@rollup/rollup-linux-s390x-gnu@4.60.1':
-    optional: true
-
   '@rollup/rollup-linux-s390x-gnu@4.62.2':
     optional: true
 
-  '@rollup/rollup-linux-x64-gnu@4.60.1':
-    optional: true
-
   '@rollup/rollup-linux-x64-gnu@4.62.2':
     optional: true
 
-  '@rollup/rollup-linux-x64-musl@4.60.1':
-    optional: true
-
   '@rollup/rollup-linux-x64-musl@4.62.2':
     optional: true
 
-  '@rollup/rollup-openbsd-x64@4.60.1':
-    optional: true
-
   '@rollup/rollup-openbsd-x64@4.62.2':
     optional: true
 
-  '@rollup/rollup-openharmony-arm64@4.60.1':
-    optional: true
-
   '@rollup/rollup-openharmony-arm64@4.62.2':
     optional: true
 
-  '@rollup/rollup-win32-arm64-msvc@4.60.1':
-    optional: true
-
   '@rollup/rollup-win32-arm64-msvc@4.62.2':
     optional: true
 
-  '@rollup/rollup-win32-ia32-msvc@4.60.1':
-    optional: true
-
   '@rollup/rollup-win32-ia32-msvc@4.62.2':
     optional: true
 
-  '@rollup/rollup-win32-x64-gnu@4.60.1':
-    optional: true
-
   '@rollup/rollup-win32-x64-gnu@4.62.2':
     optional: true
 
-  '@rollup/rollup-win32-x64-msvc@4.60.1':
-    optional: true
-
   '@rollup/rollup-win32-x64-msvc@4.62.2':
     optional: true
 
@@ -3303,7 +3056,7 @@ snapshots:
       eslint-visitor-keys: 3.4.3
       espree: 9.6.1
 
-  '@sveltejs/acorn-typescript@1.0.10(acorn@8.18.0)':
+  '@sveltejs/acorn-typescript@1.0.13(acorn@8.18.0)':
     dependencies:
       acorn: 8.18.0
 
@@ -3333,7 +3086,7 @@ snapshots:
       '@sveltejs/vite-plugin-svelte-inspector': 5.0.1(@sveltejs/vite-plugin-svelte@6.2.0(svelte@packages+svelte)(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)))(svelte@packages+svelte)(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
       debug: 4.4.3
       deepmerge: 4.3.1
-      magic-string: 0.30.17
+      magic-string: 0.30.21
       svelte: link:packages/svelte
       vite: 7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
       vitefu: 1.1.1(vite@7.3.5(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
@@ -3356,8 +3109,6 @@ snapshots:
 
   '@types/esrecurse@4.3.1': {}
 
-  '@types/estree@1.0.8': {}
-
   '@types/estree@1.0.9': {}
 
   '@types/json-schema@7.0.15': {}
@@ -3409,7 +3160,7 @@ snapshots:
   '@typescript-eslint/project-service@8.56.0(typescript@5.5.4)':
     dependencies:
       '@typescript-eslint/tsconfig-utils': 8.56.0(typescript@5.5.4)
-      '@typescript-eslint/types': 8.56.0
+      '@typescript-eslint/types': 8.59.4
       debug: 4.4.3
       typescript: 5.5.4
     transitivePeerDependencies:
@@ -3438,8 +3189,7 @@ snapshots:
 
   '@typescript-eslint/types@8.56.0': {}
 
-  '@typescript-eslint/types@8.59.4':
-    optional: true
+  '@typescript-eslint/types@8.59.4': {}
 
   '@typescript-eslint/typescript-estree@8.56.0(typescript@5.5.4)':
     dependencies:
@@ -3449,7 +3199,7 @@ snapshots:
       '@typescript-eslint/visitor-keys': 8.56.0
       debug: 4.4.3
       minimatch: 9.0.5
-      semver: 7.7.4
+      semver: 7.8.5
       tinyglobby: 0.2.17
       ts-api-utils: 2.4.0(typescript@5.5.4)
       typescript: 5.5.4
@@ -3683,7 +3433,7 @@ snapshots:
   detect-libc@1.0.3:
     optional: true
 
-  devalue@5.8.1: {}
+  devalue@5.9.2: {}
 
   dir-glob@3.0.1:
     dependencies:
@@ -3692,12 +3442,12 @@ snapshots:
   dts-buddy@0.5.5(typescript@5.5.4):
     dependencies:
       '@jridgewell/source-map': 0.3.6
-      '@jridgewell/sourcemap-codec': 1.5.0
+      '@jridgewell/sourcemap-codec': 1.6.0
       kleur: 4.1.5
       locate-character: 3.0.0
-      magic-string: 0.30.17
+      magic-string: 0.30.21
       sade: 1.8.1
-      tinyglobby: 0.2.15
+      tinyglobby: 0.2.17
       ts-api-utils: 1.3.0(typescript@5.5.4)
       typescript: 5.5.4
 
@@ -3815,15 +3565,15 @@ snapshots:
   eslint-plugin-svelte@3.15.0(eslint@10.0.0)(svelte@packages+svelte):
     dependencies:
       '@eslint-community/eslint-utils': 4.9.1(eslint@10.0.0)
-      '@jridgewell/sourcemap-codec': 1.5.0
+      '@jridgewell/sourcemap-codec': 1.6.0
       eslint: 10.0.0
       esutils: 2.0.3
       globals: 16.3.0
       known-css-properties: 0.37.0
-      postcss: 8.5.9
-      postcss-load-config: 3.1.4(postcss@8.5.9)
-      postcss-safe-parser: 7.0.1(postcss@8.5.9)
-      semver: 7.7.4
+      postcss: 8.5.15
+      postcss-load-config: 3.1.4(postcss@8.5.15)
+      postcss-safe-parser: 7.0.1(postcss@8.5.15)
+      semver: 7.8.5
       svelte-eslint-parser: 1.4.1(svelte@packages+svelte)
     optionalDependencies:
       svelte: link:packages/svelte
@@ -3838,7 +3588,7 @@ snapshots:
   eslint-scope@9.1.0:
     dependencies:
       '@types/esrecurse': 4.3.1
-      '@types/estree': 1.0.8
+      '@types/estree': 1.0.9
       esrecurse: 4.3.0
       estraverse: 5.3.0
 
@@ -3859,7 +3609,7 @@ snapshots:
       '@humanfs/node': 0.16.7
       '@humanwhocodes/module-importer': 1.0.1
       '@humanwhocodes/retry': 0.4.3
-      '@types/estree': 1.0.8
+      '@types/estree': 1.0.9
       ajv: 6.12.6
       cross-spawn: 7.0.6
       debug: 4.4.3
@@ -3909,9 +3659,9 @@ snapshots:
     dependencies:
       estraverse: 5.3.0
 
-  esrap@2.2.12(@typescript-eslint/types@8.59.4):
+  esrap@2.3.6(@typescript-eslint/types@8.59.4):
     dependencies:
-      '@jridgewell/sourcemap-codec': 1.5.5
+      '@jridgewell/sourcemap-codec': 1.6.0
     optionalDependencies:
       '@typescript-eslint/types': 8.59.4
 
@@ -3925,7 +3675,7 @@ snapshots:
 
   estree-walker@3.0.3:
     dependencies:
-      '@types/estree': 1.0.8
+      '@types/estree': 1.0.9
 
   esutils@2.0.3: {}
 
@@ -4111,11 +3861,11 @@ snapshots:
 
   is-reference@1.2.1:
     dependencies:
-      '@types/estree': 1.0.8
+      '@types/estree': 1.0.9
 
   is-reference@3.0.3:
     dependencies:
-      '@types/estree': 1.0.8
+      '@types/estree': 1.0.9
 
   is-subdir@1.2.0:
     dependencies:
@@ -4260,13 +4010,9 @@ snapshots:
 
   lodash.startcase@4.4.0: {}
 
-  magic-string@0.30.17:
-    dependencies:
-      '@jridgewell/sourcemap-codec': 1.5.0
-
   magic-string@0.30.21:
     dependencies:
-      '@jridgewell/sourcemap-codec': 1.5.5
+      '@jridgewell/sourcemap-codec': 1.6.0
 
   magicast@0.5.3:
     dependencies:
@@ -4276,7 +4022,7 @@ snapshots:
 
   make-dir@4.0.0:
     dependencies:
-      semver: 7.7.4
+      semver: 7.8.5
 
   merge2@1.4.1: {}
 
@@ -4305,8 +4051,6 @@ snapshots:
 
   ms@2.1.3: {}
 
-  nanoid@3.3.11: {}
-
   nanoid@3.3.13: {}
 
   natural-compare@1.4.0: {}
@@ -4403,16 +4147,16 @@ snapshots:
       '@polka/url': 1.0.0-next.25
       trouter: 4.0.0
 
-  postcss-load-config@3.1.4(postcss@8.5.9):
+  postcss-load-config@3.1.4(postcss@8.5.15):
     dependencies:
       lilconfig: 2.1.0
       yaml: 1.10.2
     optionalDependencies:
-      postcss: 8.5.9
+      postcss: 8.5.15
 
-  postcss-safe-parser@7.0.1(postcss@8.5.9):
+  postcss-safe-parser@7.0.1(postcss@8.5.15):
     dependencies:
-      postcss: 8.5.9
+      postcss: 8.5.15
 
   postcss-scss@4.0.9(postcss@8.5.15):
     dependencies:
@@ -4429,12 +4173,6 @@ snapshots:
       picocolors: 1.1.1
       source-map-js: 1.2.1
 
-  postcss@8.5.9:
-    dependencies:
-      nanoid: 3.3.11
-      picocolors: 1.1.1
-      source-map-js: 1.2.1
-
   prelude-ls@1.2.1: {}
 
   prettier-plugin-svelte@3.4.0(prettier@3.2.4)(svelte@packages+svelte):
@@ -4482,37 +4220,6 @@ snapshots:
 
   reusify@1.0.4: {}
 
-  rollup@4.60.1:
-    dependencies:
-      '@types/estree': 1.0.8
-    optionalDependencies:
-      '@rollup/rollup-android-arm-eabi': 4.60.1
-      '@rollup/rollup-android-arm64': 4.60.1
-      '@rollup/rollup-darwin-arm64': 4.60.1
-      '@rollup/rollup-darwin-x64': 4.60.1
-      '@rollup/rollup-freebsd-arm64': 4.60.1
-      '@rollup/rollup-freebsd-x64': 4.60.1
-      '@rollup/rollup-linux-arm-gnueabihf': 4.60.1
-      '@rollup/rollup-linux-arm-musleabihf': 4.60.1
-      '@rollup/rollup-linux-arm64-gnu': 4.60.1
-      '@rollup/rollup-linux-arm64-musl': 4.60.1
-      '@rollup/rollup-linux-loong64-gnu': 4.60.1
-      '@rollup/rollup-linux-loong64-musl': 4.60.1
-      '@rollup/rollup-linux-ppc64-gnu': 4.60.1
-      '@rollup/rollup-linux-ppc64-musl': 4.60.1
-      '@rollup/rollup-linux-riscv64-gnu': 4.60.1
-      '@rollup/rollup-linux-riscv64-musl': 4.60.1
-      '@rollup/rollup-linux-s390x-gnu': 4.60.1
-      '@rollup/rollup-linux-x64-gnu': 4.60.1
-      '@rollup/rollup-linux-x64-musl': 4.60.1
-      '@rollup/rollup-openbsd-x64': 4.60.1
-      '@rollup/rollup-openharmony-arm64': 4.60.1
-      '@rollup/rollup-win32-arm64-msvc': 4.60.1
-      '@rollup/rollup-win32-ia32-msvc': 4.60.1
-      '@rollup/rollup-win32-x64-gnu': 4.60.1
-      '@rollup/rollup-win32-x64-msvc': 4.60.1
-      fsevents: 2.3.3
-
   rollup@4.62.2:
     dependencies:
       '@types/estree': 1.0.9
@@ -4571,8 +4278,6 @@ snapshots:
     dependencies:
       xmlchars: 2.2.0
 
-  semver@7.7.4: {}
-
   semver@7.8.5: {}
 
   serialize-javascript@6.0.2:
@@ -4661,11 +4366,6 @@ snapshots:
 
   tinyexec@1.1.2: {}
 
-  tinyglobby@0.2.15:
-    dependencies:
-      fdir: 6.5.0(picomatch@4.0.4)
-      picomatch: 4.0.4
-
   tinyglobby@0.2.17:
     dependencies:
       fdir: 6.5.0(picomatch@4.0.4)
@@ -4830,7 +4530,7 @@ snapshots:
       std-env: 4.1.0
       tinybench: 2.9.0
       tinyexec: 1.1.2
-      tinyglobby: 0.2.15
+      tinyglobby: 0.2.17
       tinyrainbow: 3.1.0
       vite: 7.3.5(@types/node@20.19.17)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
       why-is-node-running: 2.3.0

From 4bf15ae6f304b9aa49a4396c3f51dc423d0722dc Mon Sep 17 00:00:00 2001
From: Bao Nguyen <39545125+giaBaoJS@users.noreply.github.com>
Date: Tue, 1 Sep 2026 03:23:00 +0700
Subject: [PATCH 219/222] fix: throw when `setContext` is called after an
 `await` during SSR (#18739)

Fixes #17233.
---
 .changeset/olive-mice-argue.md                   |  5 +++++
 .../98-reference/.generated/client-errors.md     |  8 --------
 .../98-reference/.generated/shared-errors.md     |  8 ++++++++
 packages/svelte/messages/client-errors/errors.md |  6 ------
 packages/svelte/messages/shared-errors/errors.md |  6 ++++++
 packages/svelte/src/internal/client/errors.js    | 16 ----------------
 packages/svelte/src/internal/server/context.js   | 11 +++++++++--
 packages/svelte/src/internal/server/renderer.js  | 13 ++++++++++---
 packages/svelte/src/internal/server/types.d.ts   |  2 ++
 packages/svelte/src/internal/shared/errors.js    | 16 ++++++++++++++++
 .../async-context-throws-after-await/_config.js  |  3 +--
 11 files changed, 57 insertions(+), 37 deletions(-)
 create mode 100644 .changeset/olive-mice-argue.md

diff --git a/.changeset/olive-mice-argue.md b/.changeset/olive-mice-argue.md
new file mode 100644
index 0000000000..6d749bcc3b
--- /dev/null
+++ b/.changeset/olive-mice-argue.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: throw `set_context_after_init` when `setContext` is called after an `await` during SSR
diff --git a/documentation/docs/98-reference/.generated/client-errors.md b/documentation/docs/98-reference/.generated/client-errors.md
index 2ab442afc3..3f37be269d 100644
--- a/documentation/docs/98-reference/.generated/client-errors.md
+++ b/documentation/docs/98-reference/.generated/client-errors.md
@@ -225,14 +225,6 @@ Rest element properties of `$props()` such as `%property%` are readonly
 The `%rune%` rune is only available inside `.svelte` and `.svelte.js/ts` files
 ```
 
-### set_context_after_init
-
-```
-`setContext` must be called when a component first initializes, not in a subsequent effect or after an `await` expression
-```
-
-This restriction only applies when using the `experimental.async` option, which will be active by default in Svelte 6.
-
 ### state_descriptors_fixed
 
 ```
diff --git a/documentation/docs/98-reference/.generated/shared-errors.md b/documentation/docs/98-reference/.generated/shared-errors.md
index 44616d7c8d..db8c45c0c7 100644
--- a/documentation/docs/98-reference/.generated/shared-errors.md
+++ b/documentation/docs/98-reference/.generated/shared-errors.md
@@ -80,6 +80,14 @@ Context was not set in the current component or any of its ancestors
 
 The [`createContext()`](svelte#createContext) utility returns a `[get, set, has]` triplet of functions. `get` will throw an error if `set` was not used to set the context in the current component or any of its ancestors.
 
+### set_context_after_init
+
+```
+`setContext` must be called when a component first initializes, not in a subsequent effect or after an `await` expression
+```
+
+This restriction only applies when using the `experimental.async` option, which will be active by default in Svelte 6.
+
 ### snippet_without_render_tag
 
 ```
diff --git a/packages/svelte/messages/client-errors/errors.md b/packages/svelte/messages/client-errors/errors.md
index 3b00d1516b..85bdd68010 100644
--- a/packages/svelte/messages/client-errors/errors.md
+++ b/packages/svelte/messages/client-errors/errors.md
@@ -171,12 +171,6 @@ This can happen if you render a hydratable on the client that was not rendered o
 
 > The `%rune%` rune is only available inside `.svelte` and `.svelte.js/ts` files
 
-## set_context_after_init
-
-> `setContext` must be called when a component first initializes, not in a subsequent effect or after an `await` expression
-
-This restriction only applies when using the `experimental.async` option, which will be active by default in Svelte 6.
-
 ## state_descriptors_fixed
 
 > Property descriptors defined on `$state` objects must contain `value` and always be `enumerable`, `configurable` and `writable`.
diff --git a/packages/svelte/messages/shared-errors/errors.md b/packages/svelte/messages/shared-errors/errors.md
index e005e34fc8..acb59b4190 100644
--- a/packages/svelte/messages/shared-errors/errors.md
+++ b/packages/svelte/messages/shared-errors/errors.md
@@ -66,6 +66,12 @@ Certain lifecycle methods can only be used during component initialisation. To f
 
 The [`createContext()`](svelte#createContext) utility returns a `[get, set, has]` triplet of functions. `get` will throw an error if `set` was not used to set the context in the current component or any of its ancestors.
 
+## set_context_after_init
+
+> `setContext` must be called when a component first initializes, not in a subsequent effect or after an `await` expression
+
+This restriction only applies when using the `experimental.async` option, which will be active by default in Svelte 6.
+
 ## snippet_without_render_tag
 
 > Attempted to render a snippet without a `{@render}` block. This would cause the snippet code to be stringified instead of its content being rendered to the DOM. To fix this, change `{snippet}` to `{@render snippet()}`.
diff --git a/packages/svelte/src/internal/client/errors.js b/packages/svelte/src/internal/client/errors.js
index d60c2dd280..175bb2e528 100644
--- a/packages/svelte/src/internal/client/errors.js
+++ b/packages/svelte/src/internal/client/errors.js
@@ -429,22 +429,6 @@ export function rune_outside_svelte(rune) {
 	}
 }
 
-/**
- * `setContext` must be called when a component first initializes, not in a subsequent effect or after an `await` expression
- * @returns {never}
- */
-export function set_context_after_init() {
-	if (DEV) {
-		const error = new Error(`set_context_after_init\n\`setContext\` must be called when a component first initializes, not in a subsequent effect or after an \`await\` expression\nhttps://svelte.dev/e/set_context_after_init`);
-
-		error.name = 'Svelte error';
-
-		throw error;
-	} else {
-		throw new Error(`https://svelte.dev/e/set_context_after_init`);
-	}
-}
-
 /**
  * Property descriptors defined on `$state` objects must contain `value` and always be `enumerable`, `configurable` and `writable`.
  * @returns {never}
diff --git a/packages/svelte/src/internal/server/context.js b/packages/svelte/src/internal/server/context.js
index b204c4c138..80d437907e 100644
--- a/packages/svelte/src/internal/server/context.js
+++ b/packages/svelte/src/internal/server/context.js
@@ -1,6 +1,7 @@
 /** @import { SSRContext } from '#server' */
 import { DEV } from 'esm-env';
 import { create_context, get_or_init_context_map } from '../shared/context.js';
+import * as e from './errors.js';
 
 /** @type {SSRContext | null} */
 export var ssr_context = null;
@@ -40,7 +41,13 @@ export function getContext(key) {
  * @returns {T}
  */
 export function setContext(key, context) {
-	get_or_init_context_map(ssr_context, 'setContext').set(key, context);
+	const context_map = get_or_init_context_map(ssr_context, 'setContext');
+
+	if (/** @type {SSRContext} */ (ssr_context).i) {
+		e.set_context_after_init();
+	}
+
+	context_map.set(key, context);
 	return context;
 }
 
@@ -61,7 +68,7 @@ export function getAllContexts() {
  * @param {Function} [fn]
  */
 export function push(fn) {
-	ssr_context = { p: ssr_context, c: null, r: null };
+	ssr_context = { p: ssr_context, c: null, r: null, i: false };
 
 	if (DEV) {
 		ssr_context.function = fn;
diff --git a/packages/svelte/src/internal/server/renderer.js b/packages/svelte/src/internal/server/renderer.js
index a30c302693..6b3c1b28dd 100644
--- a/packages/svelte/src/internal/server/renderer.js
+++ b/packages/svelte/src/internal/server/renderer.js
@@ -162,6 +162,11 @@ export class Renderer {
 		let promise = Promise.resolve(thunks[0]());
 		const promises = [promise];
 
+		if (context !== null && thunks.length > 1) {
+			// the remaining thunks run after an `await`, by which point it is too late to set context
+			context.i = true;
+		}
+
 		for (const fn of thunks.slice(1)) {
 			promise = promise.then(() => {
 				const previous_context = ssr_context;
@@ -209,7 +214,8 @@ export class Renderer {
 			...ssr_context,
 			p: parent,
 			c: null,
-			r: child
+			r: child,
+			i: ssr_context?.i ?? false
 		});
 
 		const result = fn(child);
@@ -260,7 +266,8 @@ export class Renderer {
 			...ssr_context,
 			p: parent_context,
 			c: null,
-			r: child
+			r: child,
+			i: ssr_context?.i ?? false
 		});
 
 		try {
@@ -859,7 +866,7 @@ export class Renderer {
 
 		try {
 			/** @type {SSRContext} */
-			const context = { p: null, c: options.context ?? null, r: renderer };
+			const context = { p: null, c: options.context ?? null, r: renderer, i: false };
 			set_ssr_context(context);
 
 			renderer.push(BLOCK_OPEN);
diff --git a/packages/svelte/src/internal/server/types.d.ts b/packages/svelte/src/internal/server/types.d.ts
index 899255d366..0e8a4cb678 100644
--- a/packages/svelte/src/internal/server/types.d.ts
+++ b/packages/svelte/src/internal/server/types.d.ts
@@ -9,6 +9,8 @@ export interface SSRContext {
 	c: null | Map<unknown, unknown>;
 	/** renderer */
 	r: null | Renderer;
+	/** True if initialized, i.e. an `await` was reached */
+	i: boolean;
 	/** dev mode only: the current component function */
 	function?: any;
 	/** dev mode only: the current element */
diff --git a/packages/svelte/src/internal/shared/errors.js b/packages/svelte/src/internal/shared/errors.js
index 9e41788dc1..6cbbe82ca5 100644
--- a/packages/svelte/src/internal/shared/errors.js
+++ b/packages/svelte/src/internal/shared/errors.js
@@ -101,6 +101,22 @@ export function missing_context() {
 	}
 }
 
+/**
+ * `setContext` must be called when a component first initializes, not in a subsequent effect or after an `await` expression
+ * @returns {never}
+ */
+export function set_context_after_init() {
+	if (DEV) {
+		const error = new Error(`set_context_after_init\n\`setContext\` must be called when a component first initializes, not in a subsequent effect or after an \`await\` expression\nhttps://svelte.dev/e/set_context_after_init`);
+
+		error.name = 'Svelte error';
+
+		throw error;
+	} else {
+		throw new Error(`https://svelte.dev/e/set_context_after_init`);
+	}
+}
+
 /**
  * Attempted to render a snippet without a `{@render}` block. This would cause the snippet code to be stringified instead of its content being rendered to the DOM. To fix this, change `{snippet}` to `{@render snippet()}`.
  * @returns {never}
diff --git a/packages/svelte/tests/server-side-rendering/samples/async-context-throws-after-await/_config.js b/packages/svelte/tests/server-side-rendering/samples/async-context-throws-after-await/_config.js
index 2d1b6be570..85622d23d3 100644
--- a/packages/svelte/tests/server-side-rendering/samples/async-context-throws-after-await/_config.js
+++ b/packages/svelte/tests/server-side-rendering/samples/async-context-throws-after-await/_config.js
@@ -1,7 +1,6 @@
 import { test } from '../../test';
 
 export default test({
-	skip: true, // TODO it appears there might be an actual bug here; the promise isn't ever actually awaited in spite of being awaited in the component
 	mode: ['async'],
-	error: 'lifecycle_outside_component'
+	error: 'set_context_after_init'
 });

From 6f7857af5921f03dcad2057c92be4b169ac4df4a Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Thu, 3 Sep 2026 15:24:50 +0200
Subject: [PATCH 220/222] chore: compiler profiling + parser bench (#18767)

Used these to speed up parsing/find compilation bottlenecks. Useful for
later analysis therefore committing it.
---
 benchmarking/analyze-compiler-profile.js      | 346 ++++++++++++++++++
 benchmarking/benchmarks/compiler/index.js     |   3 +
 .../benchmarks/compiler/parser.bench.js       |  58 +++
 benchmarking/compiler-profiling.md            |  43 +++
 benchmarking/profile-compiler.js              |  94 +++++
 benchmarking/run.js                           |  12 +-
 package.json                                  |   1 +
 7 files changed, 556 insertions(+), 1 deletion(-)
 create mode 100644 benchmarking/analyze-compiler-profile.js
 create mode 100644 benchmarking/benchmarks/compiler/index.js
 create mode 100644 benchmarking/benchmarks/compiler/parser.bench.js
 create mode 100644 benchmarking/compiler-profiling.md
 create mode 100644 benchmarking/profile-compiler.js

diff --git a/benchmarking/analyze-compiler-profile.js b/benchmarking/analyze-compiler-profile.js
new file mode 100644
index 0000000000..41729b7d93
--- /dev/null
+++ b/benchmarking/analyze-compiler-profile.js
@@ -0,0 +1,346 @@
+import fs from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const root = path.resolve(fileURLToPath(import.meta.url), '../..');
+const compiler_path = 'packages/svelte/src/compiler/';
+
+/**
+ * Merge V8 profiles from a Vitest run into a compiler-only flame graph and hotspot summary.
+ * Samples retain callees outside the compiler once execution has entered compiler code.
+ * @param {string} run_dir
+ */
+export function analyze_compiler_profiles(run_dir) {
+	const raw_dir = path.join(run_dir, 'raw');
+	const profile_files = fs
+		.readdirSync(raw_dir)
+		.filter((file) => file.endsWith('.cpuprofile'))
+		.sort();
+
+	if (profile_files.length === 0) {
+		throw new Error(`No CPU profiles found in ${raw_dir}`);
+	}
+
+	/** @type {Array<{ name: string, file?: string, line?: number, col?: number }>} */
+	const frames = [];
+	/** @type {Map<string, number>} */
+	const frame_indices = new Map();
+	/** @type {Map<string, { stack: number[], weight: number }>} */
+	const stacks = new Map();
+	/** @type {Map<string, Hotspot>} */
+	const hotspots = new Map();
+	/** @type {Map<string, Hotspot>} */
+	const files = new Map();
+	let total_time = 0;
+	let compiler_time = 0;
+	let garbage_collection_time = 0;
+	let total_samples = 0;
+	let compiler_samples = 0;
+
+	for (const profile_file of profile_files) {
+		let profile;
+		try {
+			profile = JSON.parse(fs.readFileSync(path.join(raw_dir, profile_file), 'utf8'));
+		} catch (error) {
+			throw new Error(`Could not parse CPU profile ${profile_file}`, { cause: error });
+		}
+		const nodes = Array.isArray(profile.nodes) ? profile.nodes : [];
+		const samples = Array.isArray(profile.samples) ? profile.samples : [];
+		const time_deltas = Array.isArray(profile.timeDeltas) ? profile.timeDeltas : [];
+		const nodes_by_id = new Map(nodes.map((node) => [node.id, node]));
+		const parents = new Map();
+
+		for (const node of nodes) {
+			for (const child of node.children || []) {
+				parents.set(child, node.id);
+			}
+		}
+
+		for (let i = 0; i < samples.length; i += 1) {
+			const weight = typeof time_deltas[i] === 'number' ? time_deltas[i] : 1;
+			const stack = get_stack(samples[i], nodes_by_id, parents);
+			total_time += weight;
+			total_samples += 1;
+
+			if (stack.at(-1)?.function_name === '(garbage collector)') {
+				garbage_collection_time += weight;
+			}
+
+			const compiler_index = stack.findIndex((frame) => frame.url.includes(compiler_path));
+			if (compiler_index === -1) continue;
+
+			const compiler_stack = stack.slice(compiler_index);
+			const stack_indices = compiler_stack.map(get_frame_index);
+			const stack_key = stack_indices.join(',');
+			const existing_stack = stacks.get(stack_key);
+
+			if (existing_stack) {
+				existing_stack.weight += weight;
+			} else {
+				stacks.set(stack_key, { stack: stack_indices, weight });
+			}
+
+			compiler_time += weight;
+			compiler_samples += 1;
+
+			const leaf = compiler_stack.at(-1);
+			if (leaf) {
+				get_hotspot(hotspots, frame_key(leaf), leaf).self += weight;
+				get_hotspot(files, leaf.url || '(native)', {
+					...leaf,
+					function_name: leaf.url || '(native)'
+				}).self += weight;
+			}
+
+			const seen_frames = new Set();
+			const seen_files = new Set();
+
+			for (const frame of compiler_stack) {
+				const key = frame_key(frame);
+				if (!seen_frames.has(key)) {
+					get_hotspot(hotspots, key, frame).inclusive += weight;
+					seen_frames.add(key);
+				}
+
+				const file = frame.url || '(native)';
+				if (!seen_files.has(file)) {
+					get_hotspot(files, file, { ...frame, function_name: file }).inclusive += weight;
+					seen_files.add(file);
+				}
+			}
+		}
+	}
+
+	if (compiler_time === 0) {
+		throw new Error('The CPU profiles contain no samples from packages/svelte/src/compiler');
+	}
+
+	const hotspot_rows = rank(hotspots, compiler_time);
+	const file_rows = rank(files, compiler_time);
+	const compact_stacks = [...stacks.values()];
+	const summary = {
+		profile_files: profile_files.length,
+		total_samples,
+		compiler_samples,
+		total_time_microseconds: total_time,
+		compiler_time_microseconds: compiler_time,
+		garbage_collection_time_microseconds: garbage_collection_time,
+		compiler_share_percent: (compiler_time * 100) / total_time,
+		hotspots: hotspot_rows,
+		files: file_rows
+	};
+	const speedscope = {
+		$schema: 'https://www.speedscope.app/file-format-schema.json',
+		name: `Svelte compiler: ${path.basename(run_dir)}`,
+		exporter: 'Svelte compiler test profiler',
+		activeProfileIndex: 0,
+		shared: { frames },
+		profiles: [
+			{
+				type: 'sampled',
+				name: 'Compiler-active samples from pnpm test',
+				unit: 'microseconds',
+				startValue: 0,
+				endValue: compiler_time,
+				samples: compact_stacks.map((entry) => entry.stack),
+				weights: compact_stacks.map((entry) => entry.weight)
+			}
+		]
+	};
+
+	fs.writeFileSync(
+		path.join(run_dir, 'flamegraph.speedscope.json'),
+		`${JSON.stringify(speedscope)}\n`
+	);
+	fs.writeFileSync(path.join(run_dir, 'summary.json'), `${JSON.stringify(summary, null, '\t')}\n`);
+	fs.writeFileSync(path.join(run_dir, 'summary.md'), render_markdown(summary));
+
+	return summary;
+
+	/** @param {Frame} frame */
+	function get_frame_index(frame) {
+		const key = frame_key(frame);
+		const existing = frame_indices.get(key);
+		if (existing !== undefined) return existing;
+
+		const index = frames.length;
+		const location = frame.url ? ` (${frame.url}:${frame.line})` : '';
+		frames.push({
+			name: `${frame.function_name}${location}`,
+			...(frame.url ? { file: frame.url, line: frame.line, col: frame.column } : {})
+		});
+		frame_indices.set(key, index);
+		return index;
+	}
+}
+
+/**
+ * @param {number} leaf_id
+ * @param {Map<number, any>} nodes_by_id
+ * @param {Map<number, number>} parents
+ * @returns {Frame[]}
+ */
+function get_stack(leaf_id, nodes_by_id, parents) {
+	/** @type {Frame[]} */
+	const stack = [];
+	const seen = new Set();
+	let id = leaf_id;
+
+	while (typeof id === 'number' && !seen.has(id)) {
+		seen.add(id);
+		const node = nodes_by_id.get(id);
+		if (!node) break;
+
+		const call_frame = node.callFrame || {};
+		stack.push({
+			function_name: call_frame.functionName || '(anonymous)',
+			url: normalize_url(call_frame.url || ''),
+			line: typeof call_frame.lineNumber === 'number' ? call_frame.lineNumber + 1 : 0,
+			column: typeof call_frame.columnNumber === 'number' ? call_frame.columnNumber + 1 : 0
+		});
+		id = parents.get(id);
+	}
+
+	return stack.reverse();
+}
+
+/** @param {string} url */
+function normalize_url(url) {
+	if (!url) return '';
+
+	let pathname = url.replace(/^\/\@fs\//, '/').replace(/[?#].*$/, '');
+	if (pathname.startsWith('file://')) {
+		try {
+			pathname = fileURLToPath(pathname);
+		} catch {
+			return url;
+		}
+	}
+
+	if (path.isAbsolute(pathname)) {
+		const relative = path.relative(root, pathname);
+		if (!relative.startsWith('..') && !path.isAbsolute(relative)) {
+			pathname = relative;
+		}
+	}
+
+	return pathname.replaceAll(path.sep, '/');
+}
+
+/** @param {Frame} frame */
+function frame_key(frame) {
+	return `${frame.function_name}\0${frame.url}\0${frame.line}\0${frame.column}`;
+}
+
+/**
+ * @param {Map<string, Hotspot>} collection
+ * @param {string} key
+ * @param {Frame} frame
+ */
+function get_hotspot(collection, key, frame) {
+	let hotspot = collection.get(key);
+	if (!hotspot) {
+		hotspot = { ...frame, self: 0, inclusive: 0 };
+		collection.set(key, hotspot);
+	}
+	return hotspot;
+}
+
+/**
+ * @param {Map<string, Hotspot>} collection
+ * @param {number} total
+ */
+function rank(collection, total) {
+	return [...collection.values()]
+		.map((hotspot) => ({
+			function: hotspot.function_name,
+			url: hotspot.url,
+			line: hotspot.line,
+			column: hotspot.column,
+			self_microseconds: hotspot.self,
+			self_percent: (hotspot.self * 100) / total,
+			inclusive_microseconds: hotspot.inclusive,
+			inclusive_percent: (hotspot.inclusive * 100) / total
+		}))
+		.sort(
+			(a, b) =>
+				b.self_microseconds - a.self_microseconds ||
+				b.inclusive_microseconds - a.inclusive_microseconds
+		);
+}
+
+/** @param {ReturnType<typeof analyze_compiler_profiles>} summary */
+function render_markdown(summary) {
+	const lines = [
+		'# Svelte compiler CPU profile',
+		'',
+		'Open `flamegraph.speedscope.json` in [Speedscope](https://www.speedscope.app/) for the interactive flame graph.',
+		'',
+		'## Coverage',
+		'',
+		'| Metric | Value |',
+		'| --- | ---: |',
+		`| Raw profiles | ${summary.profile_files} |`,
+		`| All profiled CPU time | ${format_time(summary.total_time_microseconds)} |`,
+		`| Compiler-active CPU time | ${format_time(summary.compiler_time_microseconds)} |`,
+		`| Compiler share | ${summary.compiler_share_percent.toFixed(2)}% |`,
+		`| All-process garbage collection | ${format_time(summary.garbage_collection_time_microseconds)} |`,
+		'',
+		'Compiler-active time includes external callees while a compiler frame is on the stack. Garbage collection is reported for context but cannot be attributed to compiler stacks by V8.',
+		'',
+		'## Top Self Hotspots',
+		'',
+		'| Rank | Function | Location | Self | Self % | Inclusive | Inclusive % |',
+		'| ---: | --- | --- | ---: | ---: | ---: | ---: |'
+	];
+
+	for (const [index, row] of summary.hotspots.slice(0, 50).entries()) {
+		lines.push(render_row(index, row));
+	}
+
+	lines.push(
+		'',
+		'## Top Files',
+		'',
+		'| Rank | File | Self | Self % | Inclusive | Inclusive % |',
+		'| ---: | --- | ---: | ---: | ---: | ---: |'
+	);
+
+	for (const [index, row] of summary.files.slice(0, 50).entries()) {
+		lines.push(
+			`| ${index + 1} | ${escape_cell(row.function)} | ${format_time(row.self_microseconds)} | ${row.self_percent.toFixed(2)}% | ${format_time(row.inclusive_microseconds)} | ${row.inclusive_percent.toFixed(2)}% |`
+		);
+	}
+
+	return `${lines.join('\n')}\n`;
+}
+
+/** @param {number} index @param {ReturnType<typeof rank>[number]} row */
+function render_row(index, row) {
+	const location = row.url ? `${row.url}:${row.line}:${row.column}` : '(native)';
+	return `| ${index + 1} | ${escape_cell(row.function)} | ${escape_cell(location)} | ${format_time(row.self_microseconds)} | ${row.self_percent.toFixed(2)}% | ${format_time(row.inclusive_microseconds)} | ${row.inclusive_percent.toFixed(2)}% |`;
+}
+
+/** @param {number} microseconds */
+function format_time(microseconds) {
+	return `${(microseconds / 1000).toFixed(1)} ms`;
+}
+
+/** @param {string} value */
+function escape_cell(value) {
+	return value.replaceAll('|', '\\|');
+}
+
+if (process.argv[1] && path.resolve(process.argv[1]) === fileURLToPath(import.meta.url)) {
+	const run_dir = process.argv[2];
+	if (!run_dir) {
+		console.error('Usage: node benchmarking/analyze-compiler-profile.js <profile-run-directory>');
+		process.exit(1);
+	}
+	analyze_compiler_profiles(path.resolve(run_dir));
+}
+
+/**
+ * @typedef {{ function_name: string, url: string, line: number, column: number }} Frame
+ * @typedef {Frame & { self: number, inclusive: number }} Hotspot
+ */
diff --git a/benchmarking/benchmarks/compiler/index.js b/benchmarking/benchmarks/compiler/index.js
new file mode 100644
index 0000000000..6db5ca139d
--- /dev/null
+++ b/benchmarking/benchmarks/compiler/index.js
@@ -0,0 +1,3 @@
+import { parser_benchmarks } from './parser.bench.js';
+
+export const compiler_benchmarks = parser_benchmarks;
diff --git a/benchmarking/benchmarks/compiler/parser.bench.js b/benchmarking/benchmarks/compiler/parser.bench.js
new file mode 100644
index 0000000000..3ff0fefbe7
--- /dev/null
+++ b/benchmarking/benchmarks/compiler/parser.bench.js
@@ -0,0 +1,58 @@
+import { parse } from '../../../packages/svelte/src/compiler/phases/1-parse/index.js';
+import { fastest_test } from '../../utils.js';
+
+const elements_source = Array.from(
+	{ length: 1000 },
+	(_, i) =>
+		`<!-- item ${i} --><section data-index="${i}" class="card card-${i}" title="plain text ${i}"><h2>Item ${i} has a reasonably long entity-free text value</h2><input disabled value="prefix {value} suffix"><textarea>plain {value} text</textarea></section>`
+).join('\n');
+
+const script_style_source = `<script>
+	// line comment
+	/* block comment */
+	const value = 42;
+</script>
+
+<style>
+${Array.from(
+	{ length: 1000 },
+	(_, i) => `.item-${i} { /* property ${i} */ color: red; margin-inline: ${i}px; }`
+).join('\n')}
+</style>`;
+
+const typescript_source = `${Array.from(
+	{ length: 1000 },
+	(_, i) => `<div data-index="${i}">Item ${i}</div>`
+).join('\n')}
+{value as number}
+<script lang="ts">
+	let value: number = 42;
+</script>${' \n'.repeat(1000)}`;
+
+/**
+ * @param {string} label
+ * @param {string} source
+ * @param {number} iterations
+ */
+function create_parser_benchmark(label, source, iterations) {
+	return {
+		label,
+		fn: async () => {
+			for (let i = 0; i < iterations; i++) {
+				parse(source);
+			}
+
+			return await fastest_test(10, () => {
+				for (let i = 0; i < iterations; i++) {
+					parse(source);
+				}
+			});
+		}
+	};
+}
+
+export const parser_benchmarks = [
+	create_parser_benchmark('parser_elements', elements_source, 5),
+	create_parser_benchmark('parser_script_style', script_style_source, 50),
+	create_parser_benchmark('parser_typescript', typescript_source, 25)
+];
diff --git a/benchmarking/compiler-profiling.md b/benchmarking/compiler-profiling.md
new file mode 100644
index 0000000000..cc2196958e
--- /dev/null
+++ b/benchmarking/compiler-profiling.md
@@ -0,0 +1,43 @@
+# Compiler CPU profiling
+
+Run the full test suite with V8 CPU profiling enabled in every Vitest worker:
+
+```sh
+pnpm profile:compiler
+```
+
+Arguments are passed to `pnpm test`, so a smaller smoke run can target a suite:
+
+```sh
+pnpm profile:compiler snapshot
+```
+
+Each run is stored under `benchmarking/.profiles/compiler-tests/<timestamp>`. Set
+`SVELTE_PROFILE_NAME` to give a run a stable name; existing runs are never overwritten.
+`benchmarking/.profiles/compiler-tests/latest.txt` contains the latest successful run name.
+
+Each run contains:
+
+- `raw/*.cpuprofile`: the original V8 profile from every Vitest worker
+- `flamegraph.speedscope.json`: compiler-active stacks merged for use in
+  [Speedscope](https://www.speedscope.app/)
+- `summary.md`: ranked self/inclusive hotspots and files
+- `summary.json`: the same measurements for further analysis
+- `manifest.json`: the command, revision, timestamps, and test result
+
+The merged profile includes downstream callees while a compiler source frame is on the stack.
+This captures parser, walker, and printer dependencies without including unrelated test runtime.
+V8 reports garbage collection outside the originating stack, so the summary reports process-wide
+GC separately rather than attributing it to the compiler.
+
+The default sampling interval is 5 ms. It can be changed for shorter, focused runs:
+
+```sh
+SVELTE_CPU_PROF_INTERVAL=1000 pnpm profile:compiler snapshot
+```
+
+Existing raw profiles can be analyzed again without rerunning tests:
+
+```sh
+node benchmarking/analyze-compiler-profile.js benchmarking/.profiles/compiler-tests/<run>
+```
diff --git a/benchmarking/profile-compiler.js b/benchmarking/profile-compiler.js
new file mode 100644
index 0000000000..323c2d27ea
--- /dev/null
+++ b/benchmarking/profile-compiler.js
@@ -0,0 +1,94 @@
+import fs from 'node:fs';
+import path from 'node:path';
+import { spawnSync } from 'node:child_process';
+import { fileURLToPath } from 'node:url';
+import { analyze_compiler_profiles } from './analyze-compiler-profile.js';
+
+const root = path.resolve(fileURLToPath(import.meta.url), '../..');
+const profiles_root = path.join(root, 'benchmarking/.profiles/compiler-tests');
+const requested_name = process.env.SVELTE_PROFILE_NAME;
+const run_name = safe(requested_name || new Date().toISOString().replaceAll(':', '-'));
+const run_dir = path.join(profiles_root, run_name);
+const raw_dir = path.join(run_dir, 'raw');
+const test_args = process.argv.slice(2);
+const sampling_interval = process.env.SVELTE_CPU_PROF_INTERVAL || '5000';
+
+if (fs.existsSync(run_dir)) {
+	console.error(`Profile run already exists: ${path.relative(root, run_dir)}`);
+	process.exit(1);
+}
+
+fs.mkdirSync(raw_dir, { recursive: true });
+
+const revision = spawnSync('git', ['rev-parse', 'HEAD'], {
+	cwd: root,
+	encoding: 'utf8'
+});
+const started_at = new Date().toISOString();
+const manifest_file = path.join(run_dir, 'manifest.json');
+const command = [
+	'pnpm',
+	'test',
+	'--execArgv=--cpu-prof',
+	`--execArgv=--cpu-prof-dir=${raw_dir}`,
+	`--execArgv=--cpu-prof-interval=${sampling_interval}`,
+	...test_args
+];
+
+write_manifest({
+	command,
+	revision: revision.status === 0 ? revision.stdout.trim() : null,
+	started_at,
+	status: 'running'
+});
+
+console.log(`Compiler profiles will be written to ${path.relative(root, run_dir)}`);
+
+const result = spawnSync(command[0], command.slice(1), {
+	cwd: root,
+	stdio: 'inherit'
+});
+
+let analysis_error = null;
+
+try {
+	analyze_compiler_profiles(run_dir);
+	fs.writeFileSync(path.join(profiles_root, 'latest.txt'), `${run_name}\n`);
+} catch (error) {
+	analysis_error = error instanceof Error ? error.stack || error.message : String(error);
+	console.error(analysis_error);
+}
+
+write_manifest({
+	command,
+	revision: revision.status === 0 ? revision.stdout.trim() : null,
+	started_at,
+	finished_at: new Date().toISOString(),
+	status: result.status === 0 && analysis_error === null ? 'completed' : 'failed',
+	test_exit_code: result.status,
+	test_signal: result.signal,
+	analysis_error
+});
+
+if (result.error) {
+	console.error(result.error);
+}
+
+if (result.status === 0 && analysis_error === null) {
+	console.log(
+		`Compiler flame graph: ${path.relative(root, path.join(run_dir, 'flamegraph.speedscope.json'))}`
+	);
+	console.log(`Compiler hotspot summary: ${path.relative(root, path.join(run_dir, 'summary.md'))}`);
+} else {
+	process.exitCode = result.status || 1;
+}
+
+/** @param {string} value */
+function safe(value) {
+	return value.replace(/[^a-z0-9._-]+/gi, '_');
+}
+
+/** @param {Record<string, unknown>} manifest */
+function write_manifest(manifest) {
+	fs.writeFileSync(manifest_file, `${JSON.stringify(manifest, null, '\t')}\n`);
+}
diff --git a/benchmarking/run.js b/benchmarking/run.js
index e44e816dd0..322960e866 100644
--- a/benchmarking/run.js
+++ b/benchmarking/run.js
@@ -1,6 +1,7 @@
 import { fork } from 'node:child_process';
 import { fileURLToPath } from 'node:url';
 import * as $ from '../packages/svelte/src/internal/client/index.js';
+import { compiler_benchmarks } from './benchmarks/compiler/index.js';
 import { reactivity_benchmarks } from './benchmarks/reactivity/index.js';
 import { ssr_benchmarks } from './benchmarks/ssr/index.js';
 import { with_cpu_profile } from './utils.js';
@@ -11,7 +12,9 @@ const single = process.env.BENCH_SINGLE;
 
 if (single) {
 	// child mode — run a single benchmark and report the result to the parent
-	const benchmark = [...reactivity_benchmarks, ...ssr_benchmarks].find((b) => b.label === single);
+	const benchmark = [...compiler_benchmarks, ...reactivity_benchmarks, ...ssr_benchmarks].find(
+		(b) => b.label === single
+	);
 
 	if (!benchmark) {
 		throw new Error(`Unknown benchmark ${single}`);
@@ -33,6 +36,13 @@ if (single) {
 	const filters = process.argv.slice(2);
 
 	const suites = [
+		// Commenting out because we rarely need to run it
+		// {
+		// 	benchmarks: compiler_benchmarks.filter(
+		// 		(b) => filters.length === 0 || filters.some((f) => b.label.includes(f))
+		// 	),
+		// 	name: 'compiler benchmarks'
+		// },
 		{
 			benchmarks: reactivity_benchmarks.filter(
 				(b) => filters.length === 0 || filters.some((f) => b.label.includes(f))
diff --git a/package.json b/package.json
index 8004698dd1..41f93d526c 100644
--- a/package.json
+++ b/package.json
@@ -19,6 +19,7 @@
     "lint": "eslint && prettier --check .",
     "format": "prettier --write .",
     "test": "vitest run",
+    "profile:compiler": "node ./benchmarking/profile-compiler.js",
     "changeset:version": "changeset version && pnpm -r generate:version && git add --all",
     "changeset:publish": "changeset publish",
     "bench": "NODE_ENV=production node --allow-natives-syntax ./benchmarking/run.js",

From 9e695442380a7c3bec5bf90d6c7341c3e1ae9bac Mon Sep 17 00:00:00 2001
From: JY Wey <34165386+JaiWey@users.noreply.github.com>
Date: Fri, 4 Sep 2026 02:06:28 +1200
Subject: [PATCH 221/222] fix: in non-async mode, only push variable to
 current_sources when active_reaction is updating (#18550)

fix: #16814

in non-async mode, when the derived inside `SvelteDate` is created and
evaluated, the `#reaction` is from the `active_reaction` when the
`SvelteDate` instance is created, which could possible in NON_UPDATING
state, so the derived should not be added to `current_sources` to
prevent re-run.

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/tricky-cooks-help.md               |  5 +++
 .../svelte/src/internal/client/runtime.js     |  6 ++-
 packages/svelte/tests/signals/test.ts         | 39 +++++++++++++++++++
 3 files changed, 49 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/tricky-cooks-help.md

diff --git a/.changeset/tricky-cooks-help.md b/.changeset/tricky-cooks-help.md
new file mode 100644
index 0000000000..f61c7944a1
--- /dev/null
+++ b/.changeset/tricky-cooks-help.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: in non-async mode, only push variable to current_sources when active_reaction is updating
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index a881403f58..d86c349445 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -100,7 +100,11 @@ export let current_sources = null;
 
 /** @param {Value} value */
 export function push_reaction_value(value) {
-	if (active_reaction !== null && (!async_mode_flag || (active_reaction.f & DERIVED) !== 0)) {
+	if (
+		active_reaction !== null &&
+		((!async_mode_flag && (active_reaction.f & REACTION_IS_UPDATING) !== 0) ||
+			(active_reaction.f & DERIVED) !== 0)
+	) {
 		(current_sources ??= new Set()).add(value);
 	}
 }
diff --git a/packages/svelte/tests/signals/test.ts b/packages/svelte/tests/signals/test.ts
index c1ebc3ec75..285dc1b3ce 100644
--- a/packages/svelte/tests/signals/test.ts
+++ b/packages/svelte/tests/signals/test.ts
@@ -1591,4 +1591,43 @@ describe('signals', () => {
 			assert.equal(s.reactions, null);
 		};
 	});
+
+	// https://github.com/sveltejs/svelte/issues/16814
+	it('does not treat values created for inactive reactions as current', () => {
+		push({}, true);
+
+		const trigger = state(false);
+		const value = state(0);
+		const log: number[] = [];
+		let inactive_reaction: Effect;
+
+		const destroy = effect_root(() => {
+			render_effect(() => {
+				$.get(trigger);
+				inactive_reaction = $.active_reaction as Effect;
+			});
+
+			render_effect(() => {
+				$.get(trigger);
+
+				const reaction = $.active_reaction;
+				$.set_active_reaction(inactive_reaction);
+				$.push_reaction_value(value);
+				$.set_active_reaction(reaction);
+
+				log.push($.get(value));
+			});
+		});
+
+		try {
+			flushSync();
+			flushSync(() => set(trigger, true));
+			flushSync(() => set(value, 1));
+
+			assert.deepEqual(log, [0, 0, 1]);
+		} finally {
+			destroy();
+			pop();
+		}
+	});
 });

From 5895c637b04dc8667020c8d326807c3f3a984472 Mon Sep 17 00:00:00 2001
From: Bao Nguyen <39545125+giaBaoJS@users.noreply.github.com>
Date: Thu, 3 Sep 2026 21:31:52 +0700
Subject: [PATCH 222/222] fix: recognise `aria-braillelabel` and
 `aria-brailleroledescription` as known ARIA attributes (#18765)

---
 .changeset/wild-cases-smile.md                               | 5 +++++
 .../phases/2-analyze/visitors/shared/a11y/constants.js       | 2 +-
 .../tests/validator/samples/a11y-aria-props/input.svelte     | 3 ++-
 3 files changed, 8 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/wild-cases-smile.md

diff --git a/.changeset/wild-cases-smile.md b/.changeset/wild-cases-smile.md
new file mode 100644
index 0000000000..ac5edacfd1
--- /dev/null
+++ b/.changeset/wild-cases-smile.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: recognise `aria-braillelabel` and `aria-brailleroledescription` as known ARIA attributes
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/a11y/constants.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/a11y/constants.js
index 49099c2cb1..a2cd91333b 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/a11y/constants.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/a11y/constants.js
@@ -4,7 +4,7 @@ import { roles as roles_map, elementRoles } from 'aria-query';
 import { AXObjects, elementAXObjects } from 'axobject-query';
 
 export const aria_attributes =
-	'activedescendant atomic autocomplete busy checked colcount colindex colspan controls current describedby description details disabled dropeffect errormessage expanded flowto grabbed haspopup hidden invalid keyshortcuts label labelledby level live modal multiline multiselectable orientation owns placeholder posinset pressed readonly relevant required roledescription rowcount rowindex rowspan selected setsize sort valuemax valuemin valuenow valuetext'.split(
+	'activedescendant atomic autocomplete braillelabel brailleroledescription busy checked colcount colindex colspan controls current describedby description details disabled dropeffect errormessage expanded flowto grabbed haspopup hidden invalid keyshortcuts label labelledby level live modal multiline multiselectable orientation owns placeholder posinset pressed readonly relevant required roledescription rowcount rowindex rowspan selected setsize sort valuemax valuemin valuenow valuetext'.split(
 		' '
 	);
 
diff --git a/packages/svelte/tests/validator/samples/a11y-aria-props/input.svelte b/packages/svelte/tests/validator/samples/a11y-aria-props/input.svelte
index 21c6327960..7e4bf7b3b3 100644
--- a/packages/svelte/tests/validator/samples/a11y-aria-props/input.svelte
+++ b/packages/svelte/tests/validator/samples/a11y-aria-props/input.svelte
@@ -1 +1,2 @@
-<input type="image" aria-labeledby="foo">
\ No newline at end of file
+<input type="image" aria-labeledby="foo">
+<div aria-braillelabel="foo" aria-brailleroledescription="bar"></div>