From 4e6104a9393e1b24831909bb3f6811568c3db413 Mon Sep 17 00:00:00 2001
From: Yash <69746573+xambassador@users.noreply.github.com>
Date: Fri, 12 Dec 2025 00:31:59 +0530
Subject: [PATCH 001/142] fix typo (#17347)

---
 packages/svelte/tests/README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/svelte/tests/README.md b/packages/svelte/tests/README.md
index 6dde66f6cb..9e450a7176 100644
--- a/packages/svelte/tests/README.md
+++ b/packages/svelte/tests/README.md
@@ -1,6 +1,6 @@
 # Test repo
 
-This repo tries to migrate as many tests from the currente Svelte project over to test against the new compiler/runtime.
+This repo tries to migrate as many tests from the current Svelte project over to test against the new compiler/runtime.
 
 ## Differences to the old test suite
 

From b268ccbf44a68353abd5e5dd9e48376afcd8a1ba Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Thu, 11 Dec 2025 15:19:40 -0500
Subject: [PATCH 002/142] fix: correctly reschedule deferred effects when
 reviving a batch after async work (#17332)

* WIP

* test

* fix: correctly reschedule deferred effects when reviving a batch after async work
---
 .changeset/lucky-wasps-grab.md                |  5 +++
 .../src/internal/client/reactivity/batch.js   | 33 ++++++++-----------
 .../Child.svelte                              |  3 ++
 .../async-reschedule-during-flush/_config.js  | 26 +++++++++++++++
 .../async-reschedule-during-flush/main.svelte | 23 +++++++++++++
 5 files changed, 71 insertions(+), 19 deletions(-)
 create mode 100644 .changeset/lucky-wasps-grab.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-reschedule-during-flush/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-reschedule-during-flush/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-reschedule-during-flush/main.svelte

diff --git a/.changeset/lucky-wasps-grab.md b/.changeset/lucky-wasps-grab.md
new file mode 100644
index 0000000000..d2d2283ccd
--- /dev/null
+++ b/.changeset/lucky-wasps-grab.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: correctly reschedule deferred effects when reviving a batch after async work
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 24dee51419..6f941c7ff2 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -44,7 +44,6 @@ import { eager_effect, unlink_effect } from './effects.js';
  *   effect: Effect | null;
  *   effects: Effect[];
  *   render_effects: Effect[];
- *   block_effects: Effect[];
  * }} EffectTarget
  */
 
@@ -128,15 +127,15 @@ export class Batch {
 
 	/**
 	 * Deferred effects (which run after async work has completed) that are DIRTY
-	 * @type {Effect[]}
+	 * @type {Set<Effect>}
 	 */
-	#dirty_effects = [];
+	#dirty_effects = new Set();
 
 	/**
 	 * Deferred effects that are MAYBE_DIRTY
-	 * @type {Effect[]}
+	 * @type {Set<Effect>}
 	 */
-	#maybe_dirty_effects = [];
+	#maybe_dirty_effects = new Set();
 
 	/**
 	 * A set of branches that still exist, but will be destroyed when this batch
@@ -167,8 +166,7 @@ export class Batch {
 			parent: null,
 			effect: null,
 			effects: [],
-			render_effects: [],
-			block_effects: []
+			render_effects: []
 		};
 
 		for (const root of root_effects) {
@@ -187,7 +185,6 @@ export class Batch {
 		if (this.is_deferred()) {
 			this.#defer_effects(target.effects);
 			this.#defer_effects(target.render_effects);
-			this.#defer_effects(target.block_effects);
 		} else {
 			// If sources are written to, then work needs to happen in a separate batch, else prior sources would be mixed with
 			// newly updated sources, which could lead to infinite loops when effects run over and over again.
@@ -228,8 +225,7 @@ export class Batch {
 					parent: target,
 					effect,
 					effects: [],
-					render_effects: [],
-					block_effects: []
+					render_effects: []
 				};
 			}
 
@@ -241,7 +237,7 @@ export class Batch {
 				} else if (async_mode_flag && (flags & (RENDER_EFFECT | MANAGED_EFFECT)) !== 0) {
 					target.render_effects.push(effect);
 				} else if (is_dirty(effect)) {
-					if ((effect.f & BLOCK_EFFECT) !== 0) target.block_effects.push(effect);
+					if ((effect.f & BLOCK_EFFECT) !== 0) this.#dirty_effects.add(effect);
 					update_effect(effect);
 				}
 
@@ -263,7 +259,6 @@ export class Batch {
 					// once the boundary is ready?
 					this.#defer_effects(target.effects);
 					this.#defer_effects(target.render_effects);
-					this.#defer_effects(target.block_effects);
 
 					target = /** @type {EffectTarget} */ (target.parent);
 				}
@@ -279,8 +274,11 @@ export class Batch {
 	 */
 	#defer_effects(effects) {
 		for (const e of effects) {
-			const target = (e.f & DIRTY) !== 0 ? this.#dirty_effects : this.#maybe_dirty_effects;
-			target.push(e);
+			if ((e.f & DIRTY) !== 0) {
+				this.#dirty_effects.add(e);
+			} else if ((e.f & MAYBE_DIRTY) !== 0) {
+				this.#maybe_dirty_effects.add(e);
+			}
 
 			// Since we're not executing these effects now, we need to clear any WAS_MARKED flags
 			// so that other batches can correctly reach these effects during their own traversal
@@ -390,8 +388,7 @@ export class Batch {
 				parent: null,
 				effect: null,
 				effects: [],
-				render_effects: [],
-				block_effects: []
+				render_effects: []
 			};
 
 			for (const batch of batches) {
@@ -484,6 +481,7 @@ export class Batch {
 
 	revive() {
 		for (const e of this.#dirty_effects) {
+			this.#maybe_dirty_effects.delete(e);
 			set_signal_status(e, DIRTY);
 			schedule_effect(e);
 		}
@@ -493,9 +491,6 @@ export class Batch {
 			schedule_effect(e);
 		}
 
-		this.#dirty_effects = [];
-		this.#maybe_dirty_effects = [];
-
 		this.flush();
 	}
 
diff --git a/packages/svelte/tests/runtime-runes/samples/async-reschedule-during-flush/Child.svelte b/packages/svelte/tests/runtime-runes/samples/async-reschedule-during-flush/Child.svelte
new file mode 100644
index 0000000000..2684005fcf
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-reschedule-during-flush/Child.svelte
@@ -0,0 +1,3 @@
+<script>
+	$effect(() => {})
+</script>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-reschedule-during-flush/_config.js b/packages/svelte/tests/runtime-runes/samples/async-reschedule-during-flush/_config.js
new file mode 100644
index 0000000000..a837d02f9f
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-reschedule-during-flush/_config.js
@@ -0,0 +1,26 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		const [a, b, resolve] = target.querySelectorAll('button');
+
+		a.click();
+		await tick();
+
+		b.click();
+		await tick();
+
+		resolve.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>a (true)</button>
+				<button>b (true)</button>
+				<button>resolve</button>
+				42
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-reschedule-during-flush/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-reschedule-during-flush/main.svelte
new file mode 100644
index 0000000000..48940017a8
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-reschedule-during-flush/main.svelte
@@ -0,0 +1,23 @@
+<script>
+	import Child from './Child.svelte';
+
+	let a = $state(false);
+	let b = $state(false);
+
+	let deferred = [];
+
+	function push(value) {
+		const d = Promise.withResolvers();
+		deferred.push(() => d.resolve(value))
+		return d.promise;
+	}
+</script>
+
+<button onclick={() => a = !a}>a ({a})</button>
+<button onclick={() => b = !b}>b ({b})</button>
+<button onclick={() => deferred.shift()()}>resolve</button>
+
+{#if a}
+	{await push(42)}
+	<Child />
+{/if}

From a544a9d5f3b1be263ff029c5d1fda9abb961660f Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Thu, 11 Dec 2025 15:31:08 -0500
Subject: [PATCH 003/142] Version Packages (#17343)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/lucky-wasps-grab.md    | 5 -----
 .changeset/smooth-comics-shine.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/lucky-wasps-grab.md
 delete mode 100644 .changeset/smooth-comics-shine.md

diff --git a/.changeset/lucky-wasps-grab.md b/.changeset/lucky-wasps-grab.md
deleted file mode 100644
index d2d2283ccd..0000000000
--- a/.changeset/lucky-wasps-grab.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: correctly reschedule deferred effects when reviving a batch after async work
diff --git a/.changeset/smooth-comics-shine.md b/.changeset/smooth-comics-shine.md
deleted file mode 100644
index 4bf26ed9f1..0000000000
--- a/.changeset/smooth-comics-shine.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: correctly print `!doctype` during `print`
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index b6ea395a9d..8acbef1e84 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,13 @@
 # svelte
 
+## 5.45.9
+
+### Patch Changes
+
+- fix: correctly reschedule deferred effects when reviving a batch after async work ([#17332](https://github.com/sveltejs/svelte/pull/17332))
+
+- fix: correctly print `!doctype` during `print` ([#17341](https://github.com/sveltejs/svelte/pull/17341))
+
 ## 5.45.8
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 86838513d2..abd151542d 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": "5.45.8",
+  "version": "5.45.9",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 69dae8a24e..d17a8a9a9c 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 = '5.45.8';
+export const VERSION = '5.45.9';
 export const PUBLIC_VERSION = '5';

From 00459a1d78a657e7372b2c92a8604cef8af1c511 Mon Sep 17 00:00:00 2001
From: Elliott Johnson <sejohnson@torchcloudconsulting.com>
Date: Thu, 11 Dec 2025 20:23:05 -0700
Subject: [PATCH 004/142] fix: race condition when importing
 `AsyncLocalStorage` (#17350)

* fix: race condition when importing `AsyncLocalStorage`

* types:

* tweak

* remove a line

* comment

* dumb esbuild

* final final pt2 final

* ugh
---
 .changeset/early-showers-marry.md             |  5 ++++
 .../src/internal/server/render-context.js     | 28 +++++++++++++------
 packages/svelte/tests/runtime-browser/test.ts |  1 +
 3 files changed, 26 insertions(+), 8 deletions(-)
 create mode 100644 .changeset/early-showers-marry.md

diff --git a/.changeset/early-showers-marry.md b/.changeset/early-showers-marry.md
new file mode 100644
index 0000000000..a599cefe64
--- /dev/null
+++ b/.changeset/early-showers-marry.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: race condition when importing `AsyncLocalStorage`
diff --git a/packages/svelte/src/internal/server/render-context.js b/packages/svelte/src/internal/server/render-context.js
index a33fff69d3..7a014a1b15 100644
--- a/packages/svelte/src/internal/server/render-context.js
+++ b/packages/svelte/src/internal/server/render-context.js
@@ -2,7 +2,7 @@
 /** @import { AsyncLocalStorage } from 'node:async_hooks' */
 /** @import { RenderContext } from '#server' */
 
-import { deferred } from '../shared/utils.js';
+import { deferred, noop } from '../shared/utils.js';
 import * as e from './errors.js';
 
 /** @type {Promise<void> | null} */
@@ -56,14 +56,26 @@ export async function with_render_context(fn) {
 
 /** @type {AsyncLocalStorage<RenderContext | null> | null} */
 let als = null;
+/** @type {Promise<void> | null} */
+let als_import = null;
 
-export async function init_render_context() {
-	if (als !== null) return;
-	try {
-		// @ts-ignore -- we don't include node types in the production build
-		const { AsyncLocalStorage } = await import('node:async_hooks');
-		als = new AsyncLocalStorage();
-	} catch {}
+/**
+ *
+ * @returns {Promise<void>}
+ */
+export function init_render_context() {
+	// It's important the right side of this assignment can run a maximum of one time
+	// otherwise it's possible for a very, very well-timed race condition to assign to `als`
+	// at the beginning of a render, and then another render to assign to it again, which causes
+	// the first render's second half to use a new instance of `als` which doesn't have its
+	// context anymore.
+	// @ts-ignore -- we don't include node types in the production build
+	als_import ??= import('node:async_hooks')
+		.then((hooks) => {
+			als = new hooks.AsyncLocalStorage();
+		})
+		.then(noop, noop);
+	return als_import;
 }
 
 // this has to be a function because rollup won't treeshake it if it's a constant
diff --git a/packages/svelte/tests/runtime-browser/test.ts b/packages/svelte/tests/runtime-browser/test.ts
index 63e601b115..597b2909dc 100644
--- a/packages/svelte/tests/runtime-browser/test.ts
+++ b/packages/svelte/tests/runtime-browser/test.ts
@@ -164,6 +164,7 @@ async function run_test(
 				}
 			],
 			bundle: true,
+			platform: 'node',
 			format: 'iife',
 			globalName: 'test_ssr'
 		});

From 5f249abeae003e8cbe535ef0ddc92c815c33dc3a Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Thu, 11 Dec 2025 22:26:58 -0500
Subject: [PATCH 005/142] Version Packages (#17353)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/early-showers-marry.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/early-showers-marry.md

diff --git a/.changeset/early-showers-marry.md b/.changeset/early-showers-marry.md
deleted file mode 100644
index a599cefe64..0000000000
--- a/.changeset/early-showers-marry.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: race condition when importing `AsyncLocalStorage`
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 8acbef1e84..d67510fd07 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,11 @@
 # svelte
 
+## 5.45.10
+
+### Patch Changes
+
+- fix: race condition when importing `AsyncLocalStorage` ([#17350](https://github.com/sveltejs/svelte/pull/17350))
+
 ## 5.45.9
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index abd151542d..ebbc3a0e62 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": "5.45.9",
+  "version": "5.45.10",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index d17a8a9a9c..e1b98ad1a8 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 = '5.45.9';
+export const VERSION = '5.45.10';
 export const PUBLIC_VERSION = '5';

From c86c4fdca10f9d46a024c1f672e60e1737c1f110 Mon Sep 17 00:00:00 2001
From: Elliott Johnson <sejohnson@torchcloudconsulting.com>
Date: Fri, 12 Dec 2025 13:59:26 -0700
Subject: [PATCH 006/142] feat: Add CSP support for `hydratable` (#17338)

---
 .changeset/soft-donkeys-serve.md              |  5 ++
 .../docs/06-runtime/05-hydratable.md          | 58 +++++++++++++++++
 .../98-reference/.generated/server-errors.md  |  6 ++
 .../svelte/messages/server-errors/errors.md   |  4 ++
 packages/svelte/src/internal/server/crypto.js | 41 ++++++++++++
 .../svelte/src/internal/server/crypto.test.ts | 15 +++++
 packages/svelte/src/internal/server/errors.js | 12 ++++
 packages/svelte/src/internal/server/index.js  |  9 ++-
 .../svelte/src/internal/server/renderer.js    | 62 +++++++++++++------
 .../svelte/src/internal/server/types.d.ts     |  7 +++
 packages/svelte/src/legacy/legacy-server.js   | 13 ++--
 packages/svelte/src/server/index.d.ts         |  4 +-
 .../samples/csp-config-error/_config.js       |  7 +++
 .../csp-config-error/_expected_head.html      | 12 ++++
 .../samples/csp-config-error/main.svelte      |  4 ++
 .../samples/csp-hash/_config.js               |  7 +++
 .../samples/csp-hash/_expected_head.html      | 12 ++++
 .../samples/csp-hash/main.svelte              |  4 ++
 .../samples/csp-nonce/_config.js              |  6 ++
 .../samples/csp-nonce/_expected_head.html     | 12 ++++
 .../samples/csp-nonce/main.svelte             |  4 ++
 .../tests/server-side-rendering/test.ts       | 11 +++-
 packages/svelte/types/index.d.ts              |  9 +++
 23 files changed, 294 insertions(+), 30 deletions(-)
 create mode 100644 .changeset/soft-donkeys-serve.md
 create mode 100644 packages/svelte/src/internal/server/crypto.js
 create mode 100644 packages/svelte/src/internal/server/crypto.test.ts
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/csp-config-error/_config.js
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/csp-config-error/_expected_head.html
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/csp-config-error/main.svelte
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/csp-hash/_config.js
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/csp-hash/_expected_head.html
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/csp-hash/main.svelte
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/csp-nonce/_config.js
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/csp-nonce/_expected_head.html
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/csp-nonce/main.svelte

diff --git a/.changeset/soft-donkeys-serve.md b/.changeset/soft-donkeys-serve.md
new file mode 100644
index 0000000000..f0c7236694
--- /dev/null
+++ b/.changeset/soft-donkeys-serve.md
@@ -0,0 +1,5 @@
+---
+"svelte": minor
+---
+
+feat: Add `csp` option to `render(...)`, and emit hashes when using `hydratable`
diff --git a/documentation/docs/06-runtime/05-hydratable.md b/documentation/docs/06-runtime/05-hydratable.md
index a5302f264d..f8d5130581 100644
--- a/documentation/docs/06-runtime/05-hydratable.md
+++ b/documentation/docs/06-runtime/05-hydratable.md
@@ -63,3 +63,61 @@ All data returned from a `hydratable` function must be serializable. But this do
 {await promises.one}
 {await promises.two}
 ```
+
+## CSP
+
+`hydratable` adds an inline `<script>` block to the `head` returned from `render`. If you're using [Content Security Policy](https://developer.mozilla.org/en-US/docs/Web/HTTP/Guides/CSP) (CSP), this script will likely fail to run. You can provide a `nonce` to `render`:
+
+```js
+/// file: server.js
+import { render } from 'svelte/server';
+import App from './App.svelte';
+// ---cut---
+const nonce = crypto.randomUUID();
+
+const { head, body } = await render(App, {
+	csp: { nonce }
+});
+```
+
+This will add the `nonce` to the script block, on the assumption that you will later add the same nonce to the CSP header of the document that contains it:
+
+```js
+/// file: server.js
+let response = new Response();
+let nonce = 'xyz123';
+// ---cut---
+response.headers.set(
+  'Content-Security-Policy',
+  `script-src 'nonce-${nonce}'`
+ );
+```
+
+It's essential that a `nonce` — which, British slang definition aside, means 'number used once' — is only used when dynamically server rendering an individual response.
+
+If instead you are generating static HTML ahead of time, you must use hashes instead:
+
+```js
+/// file: server.js
+import { render } from 'svelte/server';
+import App from './App.svelte';
+// ---cut---
+const { head, body, hashes } = await render(App, {
+	csp: { hash: true }
+});
+```
+
+`hashes.script` will be an array of strings like `["sha256-abcd123"]`. As with `nonce`, the hashes should be used in your CSP header:
+
+```js
+/// file: server.js
+let response = new Response();
+let hashes = { script: ['sha256-xyz123'] };
+// ---cut---
+response.headers.set(
+  'Content-Security-Policy',
+  `script-src ${hashes.script.map((hash) => `'${hash}'`).join(' ')}`
+ );
+```
+
+We recommend using `nonce` over hash if you can, as `hash` will interfere with streaming SSR in the future.
diff --git a/documentation/docs/98-reference/.generated/server-errors.md b/documentation/docs/98-reference/.generated/server-errors.md
index 4d05e04207..c98756afec 100644
--- a/documentation/docs/98-reference/.generated/server-errors.md
+++ b/documentation/docs/98-reference/.generated/server-errors.md
@@ -55,6 +55,12 @@ Cause:
 %stack%
 ```
 
+### invalid_csp
+
+```
+`csp.nonce` was set while `csp.hash` was `true`. These options cannot be used simultaneously.
+```
+
 ### lifecycle_function_unavailable
 
 ```
diff --git a/packages/svelte/messages/server-errors/errors.md b/packages/svelte/messages/server-errors/errors.md
index ac2ecc0a40..fd4c17e2a7 100644
--- a/packages/svelte/messages/server-errors/errors.md
+++ b/packages/svelte/messages/server-errors/errors.md
@@ -43,6 +43,10 @@ This error occurs when using `hydratable` multiple times with the same key. To a
 > Cause:
 > %stack%
 
+## invalid_csp
+
+> `csp.nonce` was set while `csp.hash` was `true`. These options cannot be used simultaneously.
+
 ## lifecycle_function_unavailable
 
 > `%name%(...)` is not available on the server
diff --git a/packages/svelte/src/internal/server/crypto.js b/packages/svelte/src/internal/server/crypto.js
new file mode 100644
index 0000000000..8727635481
--- /dev/null
+++ b/packages/svelte/src/internal/server/crypto.js
@@ -0,0 +1,41 @@
+import { BROWSER } from 'esm-env';
+
+let text_encoder;
+// TODO - remove this and use global `crypto` when we drop Node 18
+let crypto;
+
+/** @param {string} data */
+export async function sha256(data) {
+	text_encoder ??= new TextEncoder();
+
+	// @ts-expect-error
+	crypto ??= globalThis.crypto?.subtle?.digest
+		? globalThis.crypto
+		: // @ts-ignore - we don't install node types in the prod build
+			(await import('node:crypto')).webcrypto;
+
+	const hash_buffer = await crypto.subtle.digest('SHA-256', text_encoder.encode(data));
+
+	return base64_encode(hash_buffer);
+}
+
+/**
+ * @param {Uint8Array} bytes
+ * @returns {string}
+ */
+export function base64_encode(bytes) {
+	// Using `Buffer` is faster than iterating
+	// @ts-ignore
+	if (!BROWSER && globalThis.Buffer) {
+		// @ts-ignore
+		return globalThis.Buffer.from(bytes).toString('base64');
+	}
+
+	let binary = '';
+
+	for (let i = 0; i < bytes.length; i++) {
+		binary += String.fromCharCode(bytes[i]);
+	}
+
+	return btoa(binary);
+}
diff --git a/packages/svelte/src/internal/server/crypto.test.ts b/packages/svelte/src/internal/server/crypto.test.ts
new file mode 100644
index 0000000000..2bde86676d
--- /dev/null
+++ b/packages/svelte/src/internal/server/crypto.test.ts
@@ -0,0 +1,15 @@
+import { assert, test } from 'vitest';
+import { sha256 } from './crypto.js';
+
+const inputs = [
+	['hello world', 'uU0nuZNNPgilLlLX2n2r+sSE7+N6U4DukIj3rOLvzek='],
+	['', '47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU='],
+	['abcd', 'iNQmb9TmM40TuEX88olXnSCciXgjuSF9o+Fhk28DFYk='],
+	['the quick brown fox jumps over the lazy dog', 'Bcbgjx2f2voDFH/Lj4LxJMdtL3Dj2Ynciq2159dFC+w='],
+	['工欲善其事，必先利其器', 'oPOthkQ1c5BbPpvrr5WlUBJPyD5e6JeVdWcqBs9zvjA=']
+];
+
+test.each(inputs)('sha256("%s")', async (input, expected) => {
+	const actual = await sha256(input);
+	assert.equal(actual, expected);
+});
diff --git a/packages/svelte/src/internal/server/errors.js b/packages/svelte/src/internal/server/errors.js
index 3d6c0ffbdd..c966c32062 100644
--- a/packages/svelte/src/internal/server/errors.js
+++ b/packages/svelte/src/internal/server/errors.js
@@ -80,6 +80,18 @@ ${stack}\nhttps://svelte.dev/e/hydratable_serialization_failed`);
 	throw error;
 }
 
+/**
+ * `csp.nonce` was set while `csp.hash` was `true`. These options cannot be used simultaneously.
+ * @returns {never}
+ */
+export function invalid_csp() {
+	const error = new Error(`invalid_csp\n\`csp.nonce\` was set while \`csp.hash\` was \`true\`. These options cannot be used simultaneously.\nhttps://svelte.dev/e/invalid_csp`);
+
+	error.name = 'Svelte error';
+
+	throw error;
+}
+
 /**
  * `%name%(...)` is not available on the server
  * @param {string} name
diff --git a/packages/svelte/src/internal/server/index.js b/packages/svelte/src/internal/server/index.js
index c0dbdbda14..015db09a64 100644
--- a/packages/svelte/src/internal/server/index.js
+++ b/packages/svelte/src/internal/server/index.js
@@ -1,7 +1,6 @@
 /** @import { ComponentType, SvelteComponent, Component } from 'svelte' */
-/** @import { RenderOutput } from '#server' */
+/** @import { Csp, RenderOutput } from '#server' */
 /** @import { Store } from '#shared' */
-/** @import { AccumulatedContent } from './renderer.js' */
 export { FILENAME, HMR } from '../../constants.js';
 import { attr, clsx, to_class, to_style } from '../shared/attributes.js';
 import { is_promise, noop } from '../shared/utils.js';
@@ -18,6 +17,7 @@ import { EMPTY_COMMENT, BLOCK_CLOSE, BLOCK_OPEN, BLOCK_OPEN_ELSE } from './hydra
 import { validate_store } from '../shared/validate.js';
 import { is_boolean_attribute, is_raw_text_element, is_void } from '../../utils.js';
 import { Renderer } from './renderer.js';
+import * as e from './errors.js';
 
 // https://html.spec.whatwg.org/multipage/syntax.html#attributes-2
 // https://infra.spec.whatwg.org/#noncharacter
@@ -56,10 +56,13 @@ export function element(renderer, tag, attributes_fn = noop, children_fn = noop)
  * 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.
  * @template {Record<string, any>} Props
  * @param {Component<Props> | ComponentType<SvelteComponent<Props>>} component
- * @param {{ props?: Omit<Props, '$$slots' | '$$events'>; context?: Map<any, any>; idPrefix?: string }} [options]
+ * @param {{ props?: Omit<Props, '$$slots' | '$$events'>; context?: Map<any, any>; idPrefix?: string; csp?: Csp }} [options]
  * @returns {RenderOutput}
  */
 export function render(component, options = {}) {
+	if (options.csp?.hash && options.csp.nonce) {
+		e.invalid_csp();
+	}
 	return Renderer.render(/** @type {Component<Props>} */ (component), options);
 }
 
diff --git a/packages/svelte/src/internal/server/renderer.js b/packages/svelte/src/internal/server/renderer.js
index 0cfb1a7a93..1ecc90ba1f 100644
--- a/packages/svelte/src/internal/server/renderer.js
+++ b/packages/svelte/src/internal/server/renderer.js
@@ -1,5 +1,5 @@
 /** @import { Component } from 'svelte' */
-/** @import { HydratableContext, RenderOutput, SSRContext, SyncRenderOutput } from './types.js' */
+/** @import { Csp, HydratableContext, RenderOutput, SSRContext, SyncRenderOutput, Sha256Source } from './types.js' */
 /** @import { MaybePromise } from '#shared' */
 import { async_mode_flag } from '../flags/index.js';
 import { abort } from './abort-signal.js';
@@ -9,7 +9,7 @@ import * as w from './warnings.js';
 import { BLOCK_CLOSE, BLOCK_OPEN } from './hydration.js';
 import { attributes } from './index.js';
 import { get_render_context, with_render_context, init_render_context } from './render-context.js';
-import { DEV } from 'esm-env';
+import { sha256 } from './crypto.js';
 
 /** @typedef {'head' | 'body'} RendererType */
 /** @typedef {{ [key in RendererType]: string }} AccumulatedContent */
@@ -376,13 +376,13 @@ export class Renderer {
 	 * 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.
 	 * @template {Record<string, any>} Props
 	 * @param {Component<Props>} component
-	 * @param {{ props?: Omit<Props, '$$slots' | '$$events'>; context?: Map<any, any>; idPrefix?: string }} [options]
+	 * @param {{ props?: Omit<Props, '$$slots' | '$$events'>; context?: Map<any, any>; idPrefix?: string; csp?: Csp }} [options]
 	 * @returns {RenderOutput}
 	 */
 	static render(component, options = {}) {
 		/** @type {AccumulatedContent | undefined} */
 		let sync;
-		/** @type {Promise<AccumulatedContent> | undefined} */
+		/** @type {Promise<AccumulatedContent & { hashes: { script: Sha256Source[] } }> | undefined} */
 		let async;
 
 		const result = /** @type {RenderOutput} */ ({});
@@ -404,6 +404,11 @@ export class Renderer {
 					return (sync ??= Renderer.#render(component, options)).body;
 				}
 			},
+			hashes: {
+				value: {
+					script: ''
+				}
+			},
 			then: {
 				value:
 					/**
@@ -420,7 +425,8 @@ export class Renderer {
 							const user_result = onfulfilled({
 								head: result.head,
 								body: result.body,
-								html: result.body
+								html: result.body,
+								hashes: { script: [] }
 							});
 							return Promise.resolve(user_result);
 						}
@@ -514,8 +520,8 @@ export class Renderer {
 	 *
 	 * @template {Record<string, any>} Props
 	 * @param {Component<Props>} component
-	 * @param {{ props?: Omit<Props, '$$slots' | '$$events'>; context?: Map<any, any>; idPrefix?: string }} options
-	 * @returns {Promise<AccumulatedContent>}
+	 * @param {{ props?: Omit<Props, '$$slots' | '$$events'>; context?: Map<any, any>; idPrefix?: string; csp?: Csp }} options
+	 * @returns {Promise<AccumulatedContent & { hashes: { script: Sha256Source[] } }>}
 	 */
 	static async #render_async(component, options) {
 		const previous_context = ssr_context;
@@ -585,19 +591,19 @@ export class Renderer {
 			await comparison;
 		}
 
-		return await Renderer.#hydratable_block(ctx);
+		return await this.#hydratable_block(ctx);
 	}
 
 	/**
 	 * @template {Record<string, any>} Props
 	 * @param {'sync' | 'async'} mode
 	 * @param {import('svelte').Component<Props>} component
-	 * @param {{ props?: Omit<Props, '$$slots' | '$$events'>; context?: Map<any, any>; idPrefix?: string }} options
+	 * @param {{ props?: Omit<Props, '$$slots' | '$$events'>; context?: Map<any, any>; idPrefix?: string; csp?: Csp }} options
 	 * @returns {Renderer}
 	 */
 	static #open_render(mode, component, options) {
 		const renderer = new Renderer(
-			new SSRState(mode, options.idPrefix ? options.idPrefix + '-' : '')
+			new SSRState(mode, options.idPrefix ? options.idPrefix + '-' : '', options.csp)
 		);
 
 		renderer.push(BLOCK_OPEN);
@@ -623,6 +629,7 @@ export class Renderer {
 	/**
 	 * @param {AccumulatedContent} content
 	 * @param {Renderer} renderer
+	 * @returns {AccumulatedContent & { hashes: { script: Sha256Source[] } }}
 	 */
 	static #close_render(content, renderer) {
 		for (const cleanup of renderer.#collect_on_destroy()) {
@@ -638,14 +645,17 @@ export class Renderer {
 
 		return {
 			head,
-			body
+			body,
+			hashes: {
+				script: renderer.global.csp.script_hashes
+			}
 		};
 	}
 
 	/**
 	 * @param {HydratableContext} ctx
 	 */
-	static async #hydratable_block(ctx) {
+	async #hydratable_block(ctx) {
 		if (ctx.lookup.size === 0) {
 			return null;
 		}
@@ -669,9 +679,7 @@ export class Renderer {
 				${prelude}`;
 		}
 
-		// TODO csp -- have discussed but not implemented
-		return `
-		<script>
+		const body = `
 			{
 				${prelude}
 
@@ -681,11 +689,27 @@ export class Renderer {
 					h.set(k, v);
 				}
 			}
-		</script>`;
+		`;
+
+		let csp_attr = '';
+		if (this.global.csp.nonce) {
+			csp_attr = ` nonce="${this.global.csp.nonce}"`;
+		} else if (this.global.csp.hash) {
+			// note to future selves: this doesn't need to be optimized with a Map<body, hash>
+			// because the it's impossible for identical data to occur multiple times in a single render
+			// (this would require the same hydratable key:value pair to be serialized multiple times)
+			const hash = await sha256(body);
+			this.global.csp.script_hashes.push(`sha256-${hash}`);
+		}
+
+		return `\n\t\t<script${csp_attr}>${body}</script>`;
 	}
 }
 
 export class SSRState {
+	/** @readonly @type {Csp & { script_hashes: Sha256Source[] }} */
+	csp;
+
 	/** @readonly @type {'sync' | 'async'} */
 	mode;
 
@@ -700,10 +724,12 @@ export class SSRState {
 
 	/**
 	 * @param {'sync' | 'async'} mode
-	 * @param {string} [id_prefix]
+	 * @param {string} id_prefix
+	 * @param {Csp} csp
 	 */
-	constructor(mode, id_prefix = '') {
+	constructor(mode, id_prefix = '', csp = { hash: false }) {
 		this.mode = mode;
+		this.csp = { ...csp, script_hashes: [] };
 
 		let uid = 1;
 		this.uid = () => `${id_prefix}s${uid++}`;
diff --git a/packages/svelte/src/internal/server/types.d.ts b/packages/svelte/src/internal/server/types.d.ts
index 05ee34fb17..ea6282c176 100644
--- a/packages/svelte/src/internal/server/types.d.ts
+++ b/packages/svelte/src/internal/server/types.d.ts
@@ -15,6 +15,8 @@ export interface SSRContext {
 	element?: Element;
 }
 
+export type Csp = { nonce?: string; hash?: boolean };
+
 export interface HydratableLookupEntry {
 	value: unknown;
 	serialized: string;
@@ -33,6 +35,8 @@ export interface RenderContext {
 	hydratable: HydratableContext;
 }
 
+export type Sha256Source = `sha256-${string}`;
+
 export interface SyncRenderOutput {
 	/** HTML that goes into the `<head>` */
 	head: string;
@@ -40,6 +44,9 @@ export interface SyncRenderOutput {
 	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 a50d961751..05b329bea1 100644
--- a/packages/svelte/src/legacy/legacy-server.js
+++ b/packages/svelte/src/legacy/legacy-server.js
@@ -1,14 +1,14 @@
 /** @import { SvelteComponent } from '../index.js' */
+/** @import { Csp } from '#server' */
 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';
-import * as w from '../internal/server/warnings.js';
 
 // By having this as a separate entry point for server environments, we save the client bundle from having to include the server runtime
 
 export { createClassComponent };
 
-/** @typedef {{ head: string, html: string, css: { code: string, map: null }}} LegacyRenderResult */
+/** @typedef {{ head: string, html: string, css: { code: string, map: null }; hashes?: { script: `sha256-${string}`[] } }} LegacyRenderResult */
 
 /**
  * Takes a Svelte 5 component and returns a Svelte 4 compatible component constructor.
@@ -25,10 +25,10 @@ export { createClassComponent };
  */
 export function asClassComponent(component) {
 	const component_constructor = as_class_component(component);
-	/** @type {(props?: {}, opts?: { $$slots?: {}; context?: Map<any, any>; }) => LegacyRenderResult & PromiseLike<LegacyRenderResult> } */
-	const _render = (props, { context } = {}) => {
+	/** @type {(props?: {}, opts?: { $$slots?: {}; context?: Map<any, any>; csp?: Csp }) => LegacyRenderResult & PromiseLike<LegacyRenderResult> } */
+	const _render = (props, { context, csp } = {}) => {
 		// @ts-expect-error the typings are off, but this will work if the component is compiled in SSR mode
-		const result = render(component, { props, context });
+		const result = render(component, { props, context, csp });
 
 		const munged = Object.defineProperties(
 			/** @type {LegacyRenderResult & PromiseLike<LegacyRenderResult>} */ ({}),
@@ -65,7 +65,8 @@ export function asClassComponent(component) {
 							return onfulfilled({
 								css: munged.css,
 								head: result.head,
-								html: result.body
+								html: result.body,
+								hashes: result.hashes
 							});
 						}, onrejected);
 					}
diff --git a/packages/svelte/src/server/index.d.ts b/packages/svelte/src/server/index.d.ts
index d5a3b813e6..f54bd5a5ca 100644
--- a/packages/svelte/src/server/index.d.ts
+++ b/packages/svelte/src/server/index.d.ts
@@ -1,4 +1,4 @@
-import type { RenderOutput } from '#server';
+import type { Csp, RenderOutput } from '#server';
 import type { ComponentProps, Component, SvelteComponent, ComponentType } from 'svelte';
 
 /**
@@ -16,6 +16,7 @@ export function render<
 					props?: Omit<Props, '$$slots' | '$$events'>;
 					context?: Map<any, any>;
 					idPrefix?: string;
+					csp?: Csp;
 				}
 			]
 		: [
@@ -24,6 +25,7 @@ export function render<
 					props: Omit<Props, '$$slots' | '$$events'>;
 					context?: Map<any, any>;
 					idPrefix?: string;
+					csp?: Csp;
 				}
 			]
 ): RenderOutput;
diff --git a/packages/svelte/tests/server-side-rendering/samples/csp-config-error/_config.js b/packages/svelte/tests/server-side-rendering/samples/csp-config-error/_config.js
new file mode 100644
index 0000000000..03626fc37b
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/csp-config-error/_config.js
@@ -0,0 +1,7 @@
+import { test } from '../../test';
+
+export default test({
+	mode: ['async'],
+	csp: { hash: true, nonce: 'test-nonce' },
+	error: 'invalid_csp'
+});
diff --git a/packages/svelte/tests/server-side-rendering/samples/csp-config-error/_expected_head.html b/packages/svelte/tests/server-side-rendering/samples/csp-config-error/_expected_head.html
new file mode 100644
index 0000000000..fb3c95f51f
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/csp-config-error/_expected_head.html
@@ -0,0 +1,12 @@
+<script nonce="test-nonce">
+{
+	const r = (v) => Promise.resolve(v);
+	const h = (window.__svelte ??= {}).h ??= new Map();
+
+	for (const [k, v] of [
+		["key",r("bar")]
+	]) {
+		h.set(k, v);
+	}
+}
+</script>
\ No newline at end of file
diff --git a/packages/svelte/tests/server-side-rendering/samples/csp-config-error/main.svelte b/packages/svelte/tests/server-side-rendering/samples/csp-config-error/main.svelte
new file mode 100644
index 0000000000..2c4726edf4
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/csp-config-error/main.svelte
@@ -0,0 +1,4 @@
+<script>
+	import { hydratable } from "svelte";
+    const foo = await hydratable('key', () => Promise.resolve('bar'));
+</script>
\ No newline at end of file
diff --git a/packages/svelte/tests/server-side-rendering/samples/csp-hash/_config.js b/packages/svelte/tests/server-side-rendering/samples/csp-hash/_config.js
new file mode 100644
index 0000000000..fe28087d86
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/csp-hash/_config.js
@@ -0,0 +1,7 @@
+import { test } from '../../test';
+
+export default test({
+	mode: ['async'],
+	csp: { hash: true },
+	script_hashes: ['sha256-J0xwNm40i0NVEdHYeMRThG7y90X+P/I1ElZGnpQ0AbU=']
+});
diff --git a/packages/svelte/tests/server-side-rendering/samples/csp-hash/_expected_head.html b/packages/svelte/tests/server-side-rendering/samples/csp-hash/_expected_head.html
new file mode 100644
index 0000000000..56319255d6
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/csp-hash/_expected_head.html
@@ -0,0 +1,12 @@
+<script>
+{
+	const r = (v) => Promise.resolve(v);
+				const h = (window.__svelte ??= {}).h ??= new Map();
+
+	for (const [k, v] of [
+		["key",r("bar")]
+	]) {
+		h.set(k, v);
+	}
+}
+</script>
\ No newline at end of file
diff --git a/packages/svelte/tests/server-side-rendering/samples/csp-hash/main.svelte b/packages/svelte/tests/server-side-rendering/samples/csp-hash/main.svelte
new file mode 100644
index 0000000000..2c4726edf4
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/csp-hash/main.svelte
@@ -0,0 +1,4 @@
+<script>
+	import { hydratable } from "svelte";
+    const foo = await hydratable('key', () => Promise.resolve('bar'));
+</script>
\ No newline at end of file
diff --git a/packages/svelte/tests/server-side-rendering/samples/csp-nonce/_config.js b/packages/svelte/tests/server-side-rendering/samples/csp-nonce/_config.js
new file mode 100644
index 0000000000..320c0f67f8
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/csp-nonce/_config.js
@@ -0,0 +1,6 @@
+import { test } from '../../test';
+
+export default test({
+	mode: ['async'],
+	csp: { nonce: 'test-nonce' }
+});
diff --git a/packages/svelte/tests/server-side-rendering/samples/csp-nonce/_expected_head.html b/packages/svelte/tests/server-side-rendering/samples/csp-nonce/_expected_head.html
new file mode 100644
index 0000000000..fb3c95f51f
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/csp-nonce/_expected_head.html
@@ -0,0 +1,12 @@
+<script nonce="test-nonce">
+{
+	const r = (v) => Promise.resolve(v);
+	const h = (window.__svelte ??= {}).h ??= new Map();
+
+	for (const [k, v] of [
+		["key",r("bar")]
+	]) {
+		h.set(k, v);
+	}
+}
+</script>
\ No newline at end of file
diff --git a/packages/svelte/tests/server-side-rendering/samples/csp-nonce/main.svelte b/packages/svelte/tests/server-side-rendering/samples/csp-nonce/main.svelte
new file mode 100644
index 0000000000..2c4726edf4
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/csp-nonce/main.svelte
@@ -0,0 +1,4 @@
+<script>
+	import { hydratable } from "svelte";
+    const foo = await hydratable('key', () => Promise.resolve('bar'));
+</script>
\ No newline at end of file
diff --git a/packages/svelte/tests/server-side-rendering/test.ts b/packages/svelte/tests/server-side-rendering/test.ts
index 4b33685608..2bfc84c7a1 100644
--- a/packages/svelte/tests/server-side-rendering/test.ts
+++ b/packages/svelte/tests/server-side-rendering/test.ts
@@ -21,6 +21,8 @@ interface SSRTest extends BaseTest {
 	id_prefix?: string;
 	withoutNormalizeHtml?: boolean;
 	error?: string;
+	csp?: { nonce: string } | { hash: true };
+	script_hashes?: string[];
 }
 
 // TODO remove this shim when we can
@@ -77,7 +79,8 @@ const { test, run } = suite_with_variants<SSRTest, 'sync' | 'async', CompileOpti
 		try {
 			const render_result = render(Component, {
 				props: config.props || {},
-				idPrefix: config.id_prefix
+				idPrefix: config.id_prefix,
+				csp: config.csp
 			});
 			rendered = is_async ? await render_result : render_result;
 		} catch (error) {
@@ -94,7 +97,7 @@ const { test, run } = suite_with_variants<SSRTest, 'sync' | 'async', CompileOpti
 			assert.fail('Expected an error to be thrown, but rendering succeeded.');
 		}
 
-		const { body, head } = rendered;
+		const { body, head, hashes } = rendered;
 
 		fs.writeFileSync(
 			`${test_dir}/_output/${is_async ? 'async_rendered.html' : 'rendered.html'}`,
@@ -140,6 +143,10 @@ const { test, run } = suite_with_variants<SSRTest, 'sync' | 'async', CompileOpti
 				}
 			}
 		}
+
+		if (config.script_hashes !== undefined) {
+			assert.deepEqual(hashes.script, config.script_hashes);
+		}
 	}
 );
 
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index 9ace341e16..d276b2a628 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -2553,6 +2553,7 @@ declare module 'svelte/server' {
 						props?: Omit<Props, '$$slots' | '$$events'>;
 						context?: Map<any, any>;
 						idPrefix?: string;
+						csp?: Csp;
 					}
 				]
 			: [
@@ -2561,9 +2562,14 @@ declare module 'svelte/server' {
 						props: Omit<Props, '$$slots' | '$$events'>;
 						context?: Map<any, any>;
 						idPrefix?: string;
+						csp?: Csp;
 					}
 				]
 	): RenderOutput;
+	type Csp = { nonce?: string; hash?: boolean };
+
+	type Sha256Source = `sha256-${string}`;
+
 	interface SyncRenderOutput {
 		/** HTML that goes into the `<head>` */
 		head: string;
@@ -2571,6 +2577,9 @@ declare module 'svelte/server' {
 		html: string;
 		/** HTML that goes somewhere into the `<body>` */
 		body: string;
+		hashes: {
+			script: Sha256Source[];
+		};
 	}
 
 	type RenderOutput = SyncRenderOutput & PromiseLike<SyncRenderOutput>;

From 435da13fddaf1872a3fb46a7e8a20bb73322148e Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Fri, 12 Dec 2025 18:52:20 -0500
Subject: [PATCH 007/142] Version Packages (#17358)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/soft-donkeys-serve.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/soft-donkeys-serve.md

diff --git a/.changeset/soft-donkeys-serve.md b/.changeset/soft-donkeys-serve.md
deleted file mode 100644
index f0c7236694..0000000000
--- a/.changeset/soft-donkeys-serve.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-"svelte": minor
----
-
-feat: Add `csp` option to `render(...)`, and emit hashes when using `hydratable`
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index d67510fd07..86718d924c 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,11 @@
 # svelte
 
+## 5.46.0
+
+### Minor Changes
+
+- feat: Add `csp` option to `render(...)`, and emit hashes when using `hydratable` ([#17338](https://github.com/sveltejs/svelte/pull/17338))
+
 ## 5.45.10
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index ebbc3a0e62..74c80536d3 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": "5.45.10",
+  "version": "5.46.0",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index e1b98ad1a8..4d102bbfbd 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 = '5.45.10';
+export const VERSION = '5.46.0';
 export const PUBLIC_VERSION = '5';

From 95a895a9d91d93ea6a9f8814e2ae57ccc25ee164 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Mon, 22 Dec 2025 13:48:20 -0500
Subject: [PATCH 008/142] fix: prevent infinite loop when HMRing a component
 with an `await` (#17380)

* fix: prevent infinite loop when HMRing a component with an `await`

* update test

* fix

* reintroduce old logic to fix ever-growing stack of block effects

* update snapshot

* tweak names for clarity, simplify `update` slightly

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/giant-gifts-mate.md                |  5 +++
 .../3-transform/client/transform-client.js    | 10 +----
 .../svelte/src/internal/client/dev/hmr.js     | 39 ++++++++++++-------
 .../hmr/_expected/client/index.svelte.js      |  5 +--
 playgrounds/sandbox/run.js                    |  1 +
 playgrounds/sandbox/svelte.config.js          |  2 +-
 6 files changed, 36 insertions(+), 26 deletions(-)
 create mode 100644 .changeset/giant-gifts-mate.md

diff --git a/.changeset/giant-gifts-mate.md b/.changeset/giant-gifts-mate.md
new file mode 100644
index 0000000000..dc2486b698
--- /dev/null
+++ b/.changeset/giant-gifts-mate.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: prevent infinite loop when HMRing a component with an `await`
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 f51042eb7c..5c00aa591f 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
@@ -519,14 +519,9 @@ export function client_component(analysis, options) {
 
 	if (options.hmr) {
 		const id = b.id(analysis.name);
-		const HMR = b.id('$.HMR');
-
-		const existing = b.member(id, HMR, true);
-		const incoming = b.member(b.id('module.default'), HMR, true);
 
 		const accept_fn_body = [
-			b.stmt(b.assignment('=', b.member(incoming, 'source'), b.member(existing, 'source'))),
-			b.stmt(b.call('$.set', b.member(existing, 'source'), b.member(incoming, 'original')))
+			b.stmt(b.call(b.member(b.member(id, b.id('$.HMR'), true), 'update'), b.id('module.default')))
 		];
 
 		if (analysis.css.hash) {
@@ -535,8 +530,7 @@ export function client_component(analysis, options) {
 		}
 
 		const hmr = b.block([
-			b.stmt(b.assignment('=', id, b.call('$.hmr', id, b.thunk(b.member(existing, 'source'))))),
-
+			b.stmt(b.assignment('=', id, b.call('$.hmr', id))),
 			b.stmt(b.call('import.meta.hot.accept', b.arrow([b.id('module')], b.block(accept_fn_body))))
 		]);
 
diff --git a/packages/svelte/src/internal/client/dev/hmr.js b/packages/svelte/src/internal/client/dev/hmr.js
index 709a1b2722..9fa4e6ccbd 100644
--- a/packages/svelte/src/internal/client/dev/hmr.js
+++ b/packages/svelte/src/internal/client/dev/hmr.js
@@ -1,23 +1,25 @@
-/** @import { Source, Effect, TemplateNode } from '#client' */
+/** @import { Effect, TemplateNode } from '#client' */
 import { FILENAME, HMR } from '../../../constants.js';
 import { EFFECT_TRANSPARENT } from '#client/constants';
 import { hydrate_node, hydrating } from '../dom/hydration.js';
 import { block, branch, destroy_effect } from '../reactivity/effects.js';
-import { source } from '../reactivity/sources.js';
+import { set, source } from '../reactivity/sources.js';
 import { set_should_intro } from '../render.js';
 import { get } from '../runtime.js';
 
 /**
  * @template {(anchor: Comment, props: any) => any} Component
- * @param {Component} original
- * @param {() => Source<Component>} get_source
+ * @param {Component} fn
  */
-export function hmr(original, get_source) {
+export function hmr(fn) {
+	const current = source(fn);
+
 	/**
 	 * @param {TemplateNode} anchor
 	 * @param {any} props
 	 */
 	function wrapper(anchor, props) {
+		let component = {};
 		let instance = {};
 
 		/** @type {Effect} */
@@ -26,8 +28,9 @@ export function hmr(original, get_source) {
 		let ran = false;
 
 		block(() => {
-			const source = get_source();
-			const component = get(source);
+			if (component === (component = get(current))) {
+				return;
+			}
 
 			if (effect) {
 				// @ts-ignore
@@ -62,16 +65,24 @@ export function hmr(original, get_source) {
 	}
 
 	// @ts-expect-error
-	wrapper[FILENAME] = original[FILENAME];
+	wrapper[FILENAME] = fn[FILENAME];
 
 	// @ts-ignore
 	wrapper[HMR] = {
-		// When we accept an update, we set the original source to the new component
-		original,
-		// The `get_source` parameter reads `wrapper[HMR].source`, but in the `accept`
-		// function we always replace it with `previous[HMR].source`, which in practice
-		// means we only ever update the original
-		source: source(original)
+		fn,
+		current,
+		update: (/** @type {any} */ incoming) => {
+			// This logic ensures that the first version of the component is the one
+			// whose update function and therefore block effect is preserved across updates.
+			// If we don't do this dance and instead just use `incoming` as the new component
+			// and then update, we'll create an ever-growing stack of block effects.
+
+			// Trigger the original block effect
+			set(wrapper[HMR].current, incoming[HMR].fn);
+
+			// Replace the incoming source with the original one
+			incoming[HMR].current = wrapper[HMR].current;
+		}
 	};
 
 	return wrapper;
diff --git a/packages/svelte/tests/snapshot/samples/hmr/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/hmr/_expected/client/index.svelte.js
index 1fac1338c5..66d1a5af5a 100644
--- a/packages/svelte/tests/snapshot/samples/hmr/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/hmr/_expected/client/index.svelte.js
@@ -11,11 +11,10 @@ function Hmr($$anchor) {
 }
 
 if (import.meta.hot) {
-	Hmr = $.hmr(Hmr, () => Hmr[$.HMR].source);
+	Hmr = $.hmr(Hmr);
 
 	import.meta.hot.accept((module) => {
-		module.default[$.HMR].source = Hmr[$.HMR].source;
-		$.set(Hmr[$.HMR].source, module.default[$.HMR].original);
+		Hmr[$.HMR].update(module.default);
 	});
 }
 
diff --git a/playgrounds/sandbox/run.js b/playgrounds/sandbox/run.js
index 35bffb67a2..f79243d4e7 100644
--- a/playgrounds/sandbox/run.js
+++ b/playgrounds/sandbox/run.js
@@ -95,6 +95,7 @@ for (const generate of /** @type {const} */ (['client', 'server'])) {
 		if (generate === 'server' || FROM_HTML) {
 			from_html = compile(source, {
 				dev: DEV,
+				hmr: DEV,
 				filename: input,
 				generate,
 				runes: argv.values.runes,
diff --git a/playgrounds/sandbox/svelte.config.js b/playgrounds/sandbox/svelte.config.js
index 68ac605385..e1a6f1385b 100644
--- a/playgrounds/sandbox/svelte.config.js
+++ b/playgrounds/sandbox/svelte.config.js
@@ -1,6 +1,6 @@
 export default {
 	compilerOptions: {
-		hmr: false,
+		hmr: true,
 
 		experimental: {
 			async: true

From acd752524b0973036295aac2420a515ec55a5dd8 Mon Sep 17 00:00:00 2001
From: That Richan <11839880+that-richan@users.noreply.github.com>
Date: Mon, 22 Dec 2025 21:06:54 +0100
Subject: [PATCH 009/142] feat: type `currentTarget` in `on` function (#17370)

* feat: type `currentTarget` in `on` function

* `EventTarget &` is redundant, `Element` already extends `EventTarget`

* no need for optional chaining

* add currentTarget for other overloads

* update changeset

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/bumpy-radios-live.md        | 5 +++++
 packages/svelte/src/events/public.d.ts | 8 ++++----
 packages/svelte/tests/types/events.ts  | 2 ++
 packages/svelte/types/index.d.ts       | 8 ++++----
 4 files changed, 15 insertions(+), 8 deletions(-)
 create mode 100644 .changeset/bumpy-radios-live.md

diff --git a/.changeset/bumpy-radios-live.md b/.changeset/bumpy-radios-live.md
new file mode 100644
index 0000000000..f5aa4129c7
--- /dev/null
+++ b/.changeset/bumpy-radios-live.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: type `currentTarget` in `on` function
diff --git a/packages/svelte/src/events/public.d.ts b/packages/svelte/src/events/public.d.ts
index ff42e523b3..bf7b20c108 100644
--- a/packages/svelte/src/events/public.d.ts
+++ b/packages/svelte/src/events/public.d.ts
@@ -8,7 +8,7 @@
 export function on<Type extends keyof WindowEventMap>(
 	window: Window,
 	type: Type,
-	handler: (this: Window, event: WindowEventMap[Type]) => any,
+	handler: (this: Window, event: WindowEventMap[Type] & { currentTarget: Window }) => any,
 	options?: AddEventListenerOptions | undefined
 ): () => void;
 /**
@@ -19,7 +19,7 @@ export function on<Type extends keyof WindowEventMap>(
 export function on<Type extends keyof DocumentEventMap>(
 	document: Document,
 	type: Type,
-	handler: (this: Document, event: DocumentEventMap[Type]) => any,
+	handler: (this: Document, event: DocumentEventMap[Type] & { currentTarget: Document }) => any,
 	options?: AddEventListenerOptions | undefined
 ): () => void;
 /**
@@ -30,7 +30,7 @@ export function on<Type extends keyof DocumentEventMap>(
 export function on<Element extends HTMLElement, Type extends keyof HTMLElementEventMap>(
 	element: Element,
 	type: Type,
-	handler: (this: Element, event: HTMLElementEventMap[Type]) => any,
+	handler: (this: Element, event: HTMLElementEventMap[Type] & { currentTarget: Element }) => any,
 	options?: AddEventListenerOptions | undefined
 ): () => void;
 /**
@@ -41,7 +41,7 @@ export function on<Element extends HTMLElement, Type extends keyof HTMLElementEv
 export function on<Element extends MediaQueryList, Type extends keyof MediaQueryListEventMap>(
 	element: Element,
 	type: Type,
-	handler: (this: Element, event: MediaQueryListEventMap[Type]) => any,
+	handler: (this: Element, event: MediaQueryListEventMap[Type] & { currentTarget: Element }) => any,
 	options?: AddEventListenerOptions | undefined
 ): () => void;
 /**
diff --git a/packages/svelte/tests/types/events.ts b/packages/svelte/tests/types/events.ts
index 77891952be..a334cb5493 100644
--- a/packages/svelte/tests/types/events.ts
+++ b/packages/svelte/tests/types/events.ts
@@ -8,6 +8,8 @@ on(window, 'click', (e) => e.button);
 
 on(document, 'click', (e) => e.button);
 
+on(document.createElement('input'), 'input', (e) => e.currentTarget.value);
+
 on(
 	document.body,
 	'clidck',
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index d276b2a628..c0b89d8736 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -2810,7 +2810,7 @@ declare module 'svelte/events' {
 	export function on<Type extends keyof WindowEventMap>(
 		window: Window,
 		type: Type,
-		handler: (this: Window, event: WindowEventMap[Type]) => any,
+		handler: (this: Window, event: WindowEventMap[Type] & { currentTarget: Window }) => any,
 		options?: AddEventListenerOptions | undefined
 	): () => void;
 	/**
@@ -2821,7 +2821,7 @@ declare module 'svelte/events' {
 	export function on<Type extends keyof DocumentEventMap>(
 		document: Document,
 		type: Type,
-		handler: (this: Document, event: DocumentEventMap[Type]) => any,
+		handler: (this: Document, event: DocumentEventMap[Type] & { currentTarget: Document }) => any,
 		options?: AddEventListenerOptions | undefined
 	): () => void;
 	/**
@@ -2832,7 +2832,7 @@ declare module 'svelte/events' {
 	export function on<Element extends HTMLElement, Type extends keyof HTMLElementEventMap>(
 		element: Element,
 		type: Type,
-		handler: (this: Element, event: HTMLElementEventMap[Type]) => any,
+		handler: (this: Element, event: HTMLElementEventMap[Type] & { currentTarget: Element }) => any,
 		options?: AddEventListenerOptions | undefined
 	): () => void;
 	/**
@@ -2843,7 +2843,7 @@ declare module 'svelte/events' {
 	export function on<Element extends MediaQueryList, Type extends keyof MediaQueryListEventMap>(
 		element: Element,
 		type: Type,
-		handler: (this: Element, event: MediaQueryListEventMap[Type]) => any,
+		handler: (this: Element, event: MediaQueryListEventMap[Type] & { currentTarget: Element }) => any,
 		options?: AddEventListenerOptions | undefined
 	): () => void;
 	/**

From 31ac74fac7b1d6a1dc7aff1e462e657730aadfde Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Mon, 22 Dec 2025 15:09:30 -0500
Subject: [PATCH 010/142] fix: skip static optimisation for stateless deriveds
 after await (#17389)

---
 .changeset/deep-pears-juggle.md                          | 5 +++++
 .../phases/3-transform/client/visitors/RegularElement.js | 4 +++-
 .../phases/3-transform/client/visitors/shared/utils.js   | 2 +-
 .../samples/async-static-derived-after-await/_config.js  | 9 +++++++++
 .../samples/async-static-derived-after-await/main.svelte | 6 ++++++
 5 files changed, 24 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/deep-pears-juggle.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-static-derived-after-await/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-static-derived-after-await/main.svelte

diff --git a/.changeset/deep-pears-juggle.md b/.changeset/deep-pears-juggle.md
new file mode 100644
index 0000000000..4cba6b7dee
--- /dev/null
+++ b/.changeset/deep-pears-juggle.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: skip static optimisation for stateless deriveds after `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 50cef67171..690715df84 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
@@ -336,7 +336,9 @@ export function RegularElement(node, context) {
 		trimmed.every(
 			(node) =>
 				node.type === 'Text' ||
-				(!node.metadata.expression.has_state && !node.metadata.expression.has_await)
+				(!node.metadata.expression.has_state &&
+					!node.metadata.expression.has_await &&
+					!node.metadata.expression.has_blockers())
 		) &&
 		trimmed.some((node) => node.type === 'ExpressionTag');
 
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 6145f66d87..7256073096 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
@@ -134,7 +134,7 @@ export function build_template_chunk(
 
 			const evaluated = state.scope.evaluate(value);
 
-			has_await ||= node.metadata.expression.has_await;
+			has_await ||= node.metadata.expression.has_await || node.metadata.expression.has_blockers();
 			has_state ||= has_await || (node.metadata.expression.has_state && !evaluated.is_known);
 
 			if (values.length === 1) {
diff --git a/packages/svelte/tests/runtime-runes/samples/async-static-derived-after-await/_config.js b/packages/svelte/tests/runtime-runes/samples/async-static-derived-after-await/_config.js
new file mode 100644
index 0000000000..5c95b3149c
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-static-derived-after-await/_config.js
@@ -0,0 +1,9 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		await tick();
+		assert.htmlEqual(target.innerHTML, `<p>hello</p>`);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-static-derived-after-await/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-static-derived-after-await/main.svelte
new file mode 100644
index 0000000000..9ecc839c3c
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-static-derived-after-await/main.svelte
@@ -0,0 +1,6 @@
+<script>
+	await 0;
+	let message = $derived('hello');
+</script>
+
+<p>{message}</p>

From d8085c24badd48bfcba4d5344f9327e3b2f8fae8 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Wed, 24 Dec 2025 09:09:13 +0100
Subject: [PATCH 011/142] Version Packages (#17388)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/bumpy-radios-live.md |  5 -----
 .changeset/deep-pears-juggle.md |  5 -----
 .changeset/giant-gifts-mate.md  |  5 -----
 packages/svelte/CHANGELOG.md    | 10 ++++++++++
 packages/svelte/package.json    |  2 +-
 packages/svelte/src/version.js  |  2 +-
 6 files changed, 12 insertions(+), 17 deletions(-)
 delete mode 100644 .changeset/bumpy-radios-live.md
 delete mode 100644 .changeset/deep-pears-juggle.md
 delete mode 100644 .changeset/giant-gifts-mate.md

diff --git a/.changeset/bumpy-radios-live.md b/.changeset/bumpy-radios-live.md
deleted file mode 100644
index f5aa4129c7..0000000000
--- a/.changeset/bumpy-radios-live.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: type `currentTarget` in `on` function
diff --git a/.changeset/deep-pears-juggle.md b/.changeset/deep-pears-juggle.md
deleted file mode 100644
index 4cba6b7dee..0000000000
--- a/.changeset/deep-pears-juggle.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: skip static optimisation for stateless deriveds after `await`
diff --git a/.changeset/giant-gifts-mate.md b/.changeset/giant-gifts-mate.md
deleted file mode 100644
index dc2486b698..0000000000
--- a/.changeset/giant-gifts-mate.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: prevent infinite loop when HMRing a component with an `await`
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 86718d924c..dc0edbaf79 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,15 @@
 # svelte
 
+## 5.46.1
+
+### Patch Changes
+
+- fix: type `currentTarget` in `on` function ([#17370](https://github.com/sveltejs/svelte/pull/17370))
+
+- fix: skip static optimisation for stateless deriveds after `await` ([#17389](https://github.com/sveltejs/svelte/pull/17389))
+
+- fix: prevent infinite loop when HMRing a component with an `await` ([#17380](https://github.com/sveltejs/svelte/pull/17380))
+
 ## 5.46.0
 
 ### Minor Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 74c80536d3..7affd91207 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": "5.46.0",
+  "version": "5.46.1",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 4d102bbfbd..c28af94e19 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 = '5.46.0';
+export const VERSION = '5.46.1';
 export const PUBLIC_VERSION = '5';

From fcdb28c8827288055c95d2e79fd13cfce31b2175 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 26 Dec 2025 10:47:14 -0500
Subject: [PATCH 012/142] chore: disable HMR in playground (#17397)

---
 playgrounds/sandbox/svelte.config.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/playgrounds/sandbox/svelte.config.js b/playgrounds/sandbox/svelte.config.js
index e1a6f1385b..68ac605385 100644
--- a/playgrounds/sandbox/svelte.config.js
+++ b/playgrounds/sandbox/svelte.config.js
@@ -1,6 +1,6 @@
 export default {
 	compilerOptions: {
-		hmr: true,
+		hmr: false,
 
 		experimental: {
 			async: true

From 965bf6ceec0c6ee5347df6b04781fe9fe41aa5a5 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 26 Dec 2025 11:47:32 -0500
Subject: [PATCH 013/142] chore: better async setContext test (#17398)

---
 .../samples/async-set-context/A.svelte              | 13 +++++++++++++
 .../samples/async-set-context/B.svelte              | 12 ++++++++++++
 .../async-set-context/{Inner.svelte => C.svelte}    |  3 ++-
 .../samples/async-set-context/Outer.svelte          |  9 ---------
 .../samples/async-set-context/_config.js            |  4 ++--
 .../samples/async-set-context/main.svelte           |  4 ++--
 6 files changed, 31 insertions(+), 14 deletions(-)
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-set-context/A.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-set-context/B.svelte
 rename packages/svelte/tests/runtime-runes/samples/async-set-context/{Inner.svelte => C.svelte} (60%)
 delete mode 100644 packages/svelte/tests/runtime-runes/samples/async-set-context/Outer.svelte

diff --git a/packages/svelte/tests/runtime-runes/samples/async-set-context/A.svelte b/packages/svelte/tests/runtime-runes/samples/async-set-context/A.svelte
new file mode 100644
index 0000000000..5b85a553d4
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-set-context/A.svelte
@@ -0,0 +1,13 @@
+<script lang="ts">
+	import { setContext } from "svelte";
+	import B from "./B.svelte";
+
+	let greeting = 'hello';
+	setContext("greeting", greeting);
+
+	await Promise.resolve();
+
+	let recipient = 'world';
+</script>
+
+<B {recipient} />
diff --git a/packages/svelte/tests/runtime-runes/samples/async-set-context/B.svelte b/packages/svelte/tests/runtime-runes/samples/async-set-context/B.svelte
new file mode 100644
index 0000000000..2c93263ca5
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-set-context/B.svelte
@@ -0,0 +1,12 @@
+<script lang="ts">
+	import { setContext } from "svelte";
+	import C from "./C.svelte";
+
+	let { recipient } = $props();
+
+	// svelte-ignore state_referenced_locally
+	setContext("recipient", recipient);
+	await Promise.resolve();
+</script>
+
+<C />
diff --git a/packages/svelte/tests/runtime-runes/samples/async-set-context/Inner.svelte b/packages/svelte/tests/runtime-runes/samples/async-set-context/C.svelte
similarity index 60%
rename from packages/svelte/tests/runtime-runes/samples/async-set-context/Inner.svelte
rename to packages/svelte/tests/runtime-runes/samples/async-set-context/C.svelte
index 2c7fd5d43d..2aebf7a64f 100644
--- a/packages/svelte/tests/runtime-runes/samples/async-set-context/Inner.svelte
+++ b/packages/svelte/tests/runtime-runes/samples/async-set-context/C.svelte
@@ -2,6 +2,7 @@
 	import { getContext } from "svelte";
 
   let greeting = getContext("greeting");
+  let recipient = getContext("recipient");
 </script>
 
-<p>{greeting}</p>
\ No newline at end of file
+<p>{greeting} {recipient}</p>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-set-context/Outer.svelte b/packages/svelte/tests/runtime-runes/samples/async-set-context/Outer.svelte
deleted file mode 100644
index 9a493c5b75..0000000000
--- a/packages/svelte/tests/runtime-runes/samples/async-set-context/Outer.svelte
+++ /dev/null
@@ -1,9 +0,0 @@
-<script lang="ts">
-	import { setContext } from "svelte";
-	import Inner from "./Inner.svelte";
-
-	setContext("greeting", "hi");
-	await Promise.resolve();
-</script>
-
-<Inner />
diff --git a/packages/svelte/tests/runtime-runes/samples/async-set-context/_config.js b/packages/svelte/tests/runtime-runes/samples/async-set-context/_config.js
index 041f67a39e..aebed211cc 100644
--- a/packages/svelte/tests/runtime-runes/samples/async-set-context/_config.js
+++ b/packages/svelte/tests/runtime-runes/samples/async-set-context/_config.js
@@ -3,9 +3,9 @@ import { test } from '../../test';
 
 export default test({
 	mode: ['client', 'async-server'],
-	ssrHtml: `<p>hi</p>`,
+	ssrHtml: `<p>hello world</p>`,
 	async test({ assert, target }) {
 		await tick();
-		assert.htmlEqual(target.innerHTML, '<p>hi</p>');
+		assert.htmlEqual(target.innerHTML, '<p>hello world</p>');
 	}
 });
diff --git a/packages/svelte/tests/runtime-runes/samples/async-set-context/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-set-context/main.svelte
index 01b46bda93..e2189e7eb8 100644
--- a/packages/svelte/tests/runtime-runes/samples/async-set-context/main.svelte
+++ b/packages/svelte/tests/runtime-runes/samples/async-set-context/main.svelte
@@ -1,7 +1,7 @@
 <script lang="ts">
-	import Outer from "./Outer.svelte";
+	import A from "./A.svelte";
 
 	await Promise.resolve();
 </script>
 
-<Outer />
+<A />

From b1f44c46c3336df55ee6ebe38225ad746841af70 Mon Sep 17 00:00:00 2001
From: Tee Ming <chewteeming01@gmail.com>
Date: Sat, 3 Jan 2026 23:43:31 +0800
Subject: [PATCH 014/142] fix: correctly compile server code when using
 `$inspect` after a top-level await expression (#17407)

* add fix and test

* changeset

* Apply suggestion from @teemingc
---
 .changeset/spicy-years-stick.md                  |  5 +++++
 .../phases/3-transform/shared/transform-async.js |  9 ++++++++-
 .../async-top-level-inspect-server/_config.js    |  8 ++++++++
 .../_expected/client/index.svelte.js             | 16 ++++++++++++++++
 .../_expected/server/index.svelte.js             | 15 +++++++++++++++
 .../async-top-level-inspect-server/index.svelte  |  6 ++++++
 6 files changed, 58 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/spicy-years-stick.md
 create mode 100644 packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/_config.js
 create mode 100644 packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/_expected/client/index.svelte.js
 create mode 100644 packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/_expected/server/index.svelte.js
 create mode 100644 packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/index.svelte

diff --git a/.changeset/spicy-years-stick.md b/.changeset/spicy-years-stick.md
new file mode 100644
index 0000000000..76834e8381
--- /dev/null
+++ b/.changeset/spicy-years-stick.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: remove `$inspect` calls after await expressions when compiling for production server code
diff --git a/packages/svelte/src/compiler/phases/3-transform/shared/transform-async.js b/packages/svelte/src/compiler/phases/3-transform/shared/transform-async.js
index 2b9c219d7d..8d3a6b2769 100644
--- a/packages/svelte/src/compiler/phases/3-transform/shared/transform-async.js
+++ b/packages/svelte/src/compiler/phases/3-transform/shared/transform-async.js
@@ -86,7 +86,14 @@ export function transform_body(instance_body, runner, transform) {
 			}
 
 			if (s.node.type === 'ExpressionStatement') {
-				const expression = /** @type {ESTree.Expression} */ (transform(s.node.expression));
+				// the expression may be a $inspect call, which will be transformed into an empty statement
+				const expression = /** @type {ESTree.Expression | ESTree.EmptyStatement} */ (
+					transform(s.node.expression)
+				);
+
+				if (expression.type === 'EmptyStatement') {
+					return null;
+				}
 
 				return expression.type === 'AwaitExpression'
 					? b.thunk(expression, true)
diff --git a/packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/_config.js b/packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/_config.js
new file mode 100644
index 0000000000..6214e6b429
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/_config.js
@@ -0,0 +1,8 @@
+import { test } from '../../test';
+
+export default test({
+	compileOptions: {
+		experimental: { async: true },
+		dev: false
+	}
+});
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
new file mode 100644
index 0000000000..e8aa8dfa11
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/_expected/client/index.svelte.js
@@ -0,0 +1,16 @@
+import 'svelte/internal/disclose-version';
+import 'svelte/internal/flags/async';
+import * as $ from 'svelte/internal/client';
+
+var root = $.from_html(`<p> </p>`);
+
+export default function Async_top_level_inspect_server($$anchor) {
+	var data;
+	var $$promises = $.run([async () => data = await Promise.resolve(42),,]);
+	var p = root();
+	var text = $.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/async-top-level-inspect-server/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/_expected/server/index.svelte.js
new file mode 100644
index 0000000000..eb99a2fe1d
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/_expected/server/index.svelte.js
@@ -0,0 +1,15 @@
+import 'svelte/internal/flags/async';
+import * as $ from 'svelte/internal/server';
+
+export default function Async_top_level_inspect_server($$renderer) {
+	var data;
+	var $$promises = $$renderer.run([async () => data = await Promise.resolve(42),,]);
+
+	$$renderer.push(`<p>`);
+
+	$$renderer.async([$$promises[1]], ($$renderer) => {
+		$$renderer.push(() => $.escape(data));
+	});
+
+	$$renderer.push(`</p>`);
+}
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/index.svelte b/packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/index.svelte
new file mode 100644
index 0000000000..06bb995b1e
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/index.svelte
@@ -0,0 +1,6 @@
+<script>
+	let data = await Promise.resolve(42);
+	$inspect(data);
+</script>
+
+<p>{data}</p>

From 37f08493c966401326b4bab9763e92c0a977f71a Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Mon, 5 Jan 2026 11:55:14 +0000
Subject: [PATCH 015/142] chore: eagerly assign labels to async deriveds
 (#17420)

---
 .../client/visitors/VariableDeclaration.js            | 11 +++++------
 .../svelte/src/internal/client/reactivity/deriveds.js |  5 ++++-
 2 files changed, 9 insertions(+), 7 deletions(-)

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 57dba202ba..16aa164d84 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
@@ -209,11 +209,11 @@ export function VariableDeclaration(node, context) {
 						let call = b.call(
 							'$.async_derived',
 							b.thunk(expression, true),
+							dev && b.literal(declarator.id.name),
 							location ? b.literal(location) : undefined
 						);
 
 						call = should_save ? save(call) : b.await(call);
-						if (dev) call = b.call('$.tag', call, b.literal(declarator.id.name));
 
 						declarations.push(b.declarator(declarator.id, call));
 					} else {
@@ -244,17 +244,16 @@ export function VariableDeclaration(node, context) {
 							call = b.call(
 								'$.async_derived',
 								b.thunk(expression, true),
+								dev &&
+									b.literal(
+										`[$derived ${declarator.id.type === 'ArrayPattern' ? 'iterable' : 'object'}]`
+									),
 								location ? b.literal(location) : undefined
 							);
 
 							call = should_save ? save(call) : b.await(call);
 						}
 
-						if (dev) {
-							const label = `[$derived ${declarator.id.type === 'ArrayPattern' ? 'iterable' : 'object'}]`;
-							call = b.call('$.tag', call, b.literal(label));
-						}
-
 						declarations.push(b.declarator(id, call));
 					}
 
diff --git a/packages/svelte/src/internal/client/reactivity/deriveds.js b/packages/svelte/src/internal/client/reactivity/deriveds.js
index b2d5d59ae1..ee8ba29c21 100644
--- a/packages/svelte/src/internal/client/reactivity/deriveds.js
+++ b/packages/svelte/src/internal/client/reactivity/deriveds.js
@@ -93,11 +93,12 @@ export function derived(fn) {
 /**
  * @template V
  * @param {() => V | Promise<V>} fn
+ * @param {string} [label]
  * @param {string} [location] If provided, print a warning if the value is not read immediately after update
  * @returns {Promise<Source<V>>}
  */
 /*#__NO_SIDE_EFFECTS__*/
-export function async_derived(fn, location) {
+export function async_derived(fn, label, location) {
 	let parent = /** @type {Effect | null} */ (active_effect);
 
 	if (parent === null) {
@@ -109,6 +110,8 @@ export function async_derived(fn, location) {
 	var promise = /** @type {Promise<V>} */ (/** @type {unknown} */ (undefined));
 	var signal = source(/** @type {V} */ (UNINITIALIZED));
 
+	if (DEV) signal.label = label;
+
 	// only suspend in async deriveds created on initialisation
 	var should_suspend = !active_reaction;
 

From 1482ae8726a40329fe540fb7f20e3517edd318fd Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 7 Jan 2026 15:38:00 +0000
Subject: [PATCH 016/142] chore: remove `async_body` (#17425)

* chore: remove unused async_body

* unused
---
 packages/svelte/src/internal/client/index.js  |  1 -
 .../src/internal/client/reactivity/async.js   | 46 -------------------
 2 files changed, 47 deletions(-)

diff --git a/packages/svelte/src/internal/client/index.js b/packages/svelte/src/internal/client/index.js
index a2add3ec59..a2666d8712 100644
--- a/packages/svelte/src/internal/client/index.js
+++ b/packages/svelte/src/internal/client/index.js
@@ -98,7 +98,6 @@ export {
 	with_script
 } from './dom/template.js';
 export {
-	async_body,
 	for_await_track_reactivity_loss,
 	run,
 	save,
diff --git a/packages/svelte/src/internal/client/reactivity/async.js b/packages/svelte/src/internal/client/reactivity/async.js
index e48aff3d7f..631af24807 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_from_async_derived
 } from './deriveds.js';
 import { aborted } from './effects.js';
-import { hydrate_next, hydrating, set_hydrate_node, skip_nodes } from '../dom/hydration.js';
 
 /**
  * @param {Array<Promise<void>>} blockers
@@ -211,51 +210,6 @@ export function unset_context() {
 	}
 }
 
-/**
- * @param {TemplateNode} anchor
- * @param {(target: TemplateNode) => Promise<void>} fn
- */
-export async function async_body(anchor, fn) {
-	var boundary = get_boundary();
-	var batch = /** @type {Batch} */ (current_batch);
-	var blocking = !boundary.is_pending();
-
-	boundary.update_pending_count(1);
-	batch.increment(blocking);
-
-	var active = /** @type {Effect} */ (active_effect);
-
-	var was_hydrating = hydrating;
-	var next_hydrate_node = undefined;
-
-	if (was_hydrating) {
-		hydrate_next();
-		next_hydrate_node = skip_nodes(false);
-	}
-
-	try {
-		var promise = fn(anchor);
-	} finally {
-		if (next_hydrate_node) {
-			set_hydrate_node(next_hydrate_node);
-			hydrate_next();
-		}
-	}
-
-	try {
-		await promise;
-	} catch (error) {
-		if (!aborted(active)) {
-			invoke_error_boundary(error, active);
-		}
-	} finally {
-		boundary.update_pending_count(-1);
-		batch.decrement(blocking);
-
-		unset_context();
-	}
-}
-
 /**
  * @param {Array<() => void | Promise<void>>} thunks
  */

From 41e86438145d42c8ddf00fe1a44eaf3a7b8319c8 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 7 Jan 2026 16:39:10 +0000
Subject: [PATCH 017/142] fix: clear batch between runs (alternative approach)
 (#17424)

* fix: clear batch between runs

* changeset

* add comment and note-to-self

* associate effects with boundaries, albeit clumsily

* remove unused async_body

* dry out

* fix

* simplify

* clarify

* tweak

* unused

* unused

* add an explanatory comment
---
 .changeset/tall-clocks-turn.md                |   5 +
 .../src/internal/client/dom/blocks/async.js   |   2 +-
 .../internal/client/dom/blocks/boundary.js    |  65 ++++++---
 .../src/internal/client/reactivity/async.js   |  12 +-
 .../src/internal/client/reactivity/batch.js   | 124 ++++++------------
 .../internal/client/reactivity/deriveds.js    |   2 +-
 .../src/internal/client/reactivity/utils.js   |  40 ++++++
 .../Child.svelte                              |  15 +++
 .../async-clear-batch-between-runs/_config.js |  32 +++++
 .../main.svelte                               |  19 +++
 10 files changed, 209 insertions(+), 107 deletions(-)
 create mode 100644 .changeset/tall-clocks-turn.md
 create mode 100644 packages/svelte/src/internal/client/reactivity/utils.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-clear-batch-between-runs/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-clear-batch-between-runs/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-clear-batch-between-runs/main.svelte

diff --git a/.changeset/tall-clocks-turn.md b/.changeset/tall-clocks-turn.md
new file mode 100644
index 0000000000..22cefcff30
--- /dev/null
+++ b/.changeset/tall-clocks-turn.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: clear batch between runs
diff --git a/packages/svelte/src/internal/client/dom/blocks/async.js b/packages/svelte/src/internal/client/dom/blocks/async.js
index 3d320d2ea9..3bc1eecba7 100644
--- a/packages/svelte/src/internal/client/dom/blocks/async.js
+++ b/packages/svelte/src/internal/client/dom/blocks/async.js
@@ -21,7 +21,7 @@ import { get_boundary } from './boundary.js';
 export function async(node, blockers = [], expressions = [], fn) {
 	var boundary = get_boundary();
 	var batch = /** @type {Batch} */ (current_batch);
-	var blocking = !boundary.is_pending();
+	var blocking = boundary.is_rendered();
 
 	boundary.update_pending_count(1);
 	batch.increment(blocking);
diff --git a/packages/svelte/src/internal/client/dom/blocks/boundary.js b/packages/svelte/src/internal/client/dom/blocks/boundary.js
index 140e876330..92f4c0a104 100644
--- a/packages/svelte/src/internal/client/dom/blocks/boundary.js
+++ b/packages/svelte/src/internal/client/dom/blocks/boundary.js
@@ -2,8 +2,10 @@
 import {
 	BOUNDARY_EFFECT,
 	COMMENT_NODE,
+	DIRTY,
 	EFFECT_PRESERVED,
-	EFFECT_TRANSPARENT
+	EFFECT_TRANSPARENT,
+	MAYBE_DIRTY
 } from '#client/constants';
 import { HYDRATION_START_ELSE } from '../../../../constants.js';
 import { component_context, set_component_context } from '../../context.js';
@@ -20,7 +22,8 @@ import {
 	active_reaction,
 	get,
 	set_active_effect,
-	set_active_reaction
+	set_active_reaction,
+	set_signal_status
 } from '../../runtime.js';
 import {
 	hydrate_next,
@@ -34,11 +37,12 @@ import { queue_micro_task } from '../task.js';
 import * as e from '../../errors.js';
 import * as w from '../../warnings.js';
 import { DEV } from 'esm-env';
-import { Batch } from '../../reactivity/batch.js';
+import { Batch, schedule_effect } from '../../reactivity/batch.js';
 import { internal_set, source } from '../../reactivity/sources.js';
 import { tag } from '../../dev/tracing.js';
 import { createSubscriber } from '../../../../reactivity/create-subscriber.js';
 import { create_text } from '../operations.js';
+import { defer_effect } from '../../reactivity/utils.js';
 
 /**
  * @typedef {{
@@ -64,7 +68,7 @@ export class Boundary {
 	/** @type {Boundary | null} */
 	parent;
 
-	#pending = false;
+	is_pending = false;
 
 	/** @type {TemplateNode} */
 	#anchor;
@@ -101,6 +105,12 @@ export class Boundary {
 
 	#is_creating_fallback = false;
 
+	/** @type {Set<Effect>} */
+	#dirty_effects = new Set();
+
+	/** @type {Set<Effect>} */
+	#maybe_dirty_effects = new Set();
+
 	/**
 	 * A source containing the number of pending async deriveds/expressions.
 	 * Only created if `$effect.pending()` is used inside the boundary,
@@ -134,7 +144,7 @@ export class Boundary {
 
 		this.parent = /** @type {Effect} */ (active_effect).b;
 
-		this.#pending = !!this.#props.pending;
+		this.is_pending = !!this.#props.pending;
 
 		this.#effect = block(() => {
 			/** @type {Effect} */ (active_effect).b = this;
@@ -164,7 +174,7 @@ export class Boundary {
 				if (this.#pending_count > 0) {
 					this.#show_pending_snippet();
 				} else {
-					this.#pending = false;
+					this.is_pending = false;
 				}
 			}
 
@@ -187,7 +197,7 @@ export class Boundary {
 
 		// Since server rendered resolved content, we never show pending state
 		// Even if client-side async operations are still running, the content is already displayed
-		this.#pending = false;
+		this.is_pending = false;
 	}
 
 	#hydrate_pending_content() {
@@ -212,7 +222,7 @@ export class Boundary {
 					this.#pending_effect = null;
 				});
 
-				this.#pending = false;
+				this.is_pending = false;
 			}
 		});
 	}
@@ -220,7 +230,7 @@ export class Boundary {
 	#get_anchor() {
 		var anchor = this.#anchor;
 
-		if (this.#pending) {
+		if (this.is_pending) {
 			this.#pending_anchor = create_text();
 			this.#anchor.before(this.#pending_anchor);
 
@@ -231,11 +241,19 @@ export class Boundary {
 	}
 
 	/**
-	 * Returns `true` if the effect exists inside a boundary whose pending snippet is shown
+	 * Defer an effect inside a pending boundary until the boundary resolves
+	 * @param {Effect} effect
+	 */
+	defer_effect(effect) {
+		defer_effect(effect, this.#dirty_effects, this.#maybe_dirty_effects);
+	}
+
+	/**
+	 * Returns `false` if the effect exists inside a boundary whose pending snippet is shown
 	 * @returns {boolean}
 	 */
-	is_pending() {
-		return this.#pending || (!!this.parent && this.parent.is_pending());
+	is_rendered() {
+		return !this.is_pending && (!this.parent || this.parent.is_rendered());
 	}
 
 	has_pending_snippet() {
@@ -298,7 +316,24 @@ export class Boundary {
 		this.#pending_count += d;
 
 		if (this.#pending_count === 0) {
-			this.#pending = false;
+			this.is_pending = false;
+
+			// any effects that were encountered and deferred during traversal
+			// should be rescheduled — after the next traversal (which will happen
+			// immediately, due to the same update that brought us here)
+			// the effects will be flushed
+			for (const e of this.#dirty_effects) {
+				set_signal_status(e, DIRTY);
+				schedule_effect(e);
+			}
+
+			for (const e of this.#maybe_dirty_effects) {
+				set_signal_status(e, MAYBE_DIRTY);
+				schedule_effect(e);
+			}
+
+			this.#dirty_effects.clear();
+			this.#maybe_dirty_effects.clear();
 
 			if (this.#pending_effect) {
 				pause_effect(this.#pending_effect, () => {
@@ -394,7 +429,7 @@ export class Boundary {
 
 			// we intentionally do not try to find the nearest pending boundary. If this boundary has one, we'll render it on reset
 			// but it would be really weird to show the parent's boundary on a child reset.
-			this.#pending = this.has_pending_snippet();
+			this.is_pending = this.has_pending_snippet();
 
 			this.#main_effect = this.#run(() => {
 				this.#is_creating_fallback = false;
@@ -404,7 +439,7 @@ export class Boundary {
 			if (this.#pending_count > 0) {
 				this.#show_pending_snippet();
 			} else {
-				this.#pending = false;
+				this.is_pending = false;
 			}
 		};
 
diff --git a/packages/svelte/src/internal/client/reactivity/async.js b/packages/svelte/src/internal/client/reactivity/async.js
index 631af24807..334bf8f145 100644
--- a/packages/svelte/src/internal/client/reactivity/async.js
+++ b/packages/svelte/src/internal/client/reactivity/async.js
@@ -218,7 +218,7 @@ export function run(thunks) {
 
 	var boundary = get_boundary();
 	var batch = /** @type {Batch} */ (current_batch);
-	var blocking = !boundary.is_pending();
+	var blocking = boundary.is_rendered();
 
 	boundary.update_pending_count(1);
 	batch.increment(blocking);
@@ -252,17 +252,13 @@ export function run(thunks) {
 					throw STALE_REACTION;
 				}
 
-				try {
-					restore();
-					return fn();
-				} finally {
-					// TODO do we need it here as well as below?
-					unset_context();
-				}
+				restore();
+				return fn();
 			})
 			.catch(handle_error)
 			.finally(() => {
 				unset_context();
+				current_batch?.deactivate();
 			});
 
 		promises.push(promise);
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 6f941c7ff2..6dd90ba1b4 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -1,5 +1,6 @@
 /** @import { Fork } from 'svelte' */
 /** @import { Derived, Effect, Reaction, Source, Value } from '#client' */
+/** @import { Boundary } from '../dom/blocks/boundary' */
 import {
 	BLOCK_EFFECT,
 	BRANCH_EFFECT,
@@ -17,7 +18,6 @@ import {
 	EAGER_EFFECT,
 	HEAD_EFFECT,
 	ERROR_VALUE,
-	WAS_MARKED,
 	MANAGED_EFFECT
 } from '#client/constants';
 import { async_mode_flag } from '../../flags/index.js';
@@ -37,15 +37,7 @@ 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';
-
-/**
- * @typedef {{
- *   parent: EffectTarget | null;
- *   effect: Effect | null;
- *   effects: Effect[];
- *   render_effects: Effect[];
- * }} EffectTarget
- */
+import { defer_effect } from './utils.js';
 
 /** @type {Set<Batch>} */
 const batches = new Set();
@@ -161,16 +153,14 @@ export class Batch {
 
 		this.apply();
 
-		/** @type {EffectTarget} */
-		var target = {
-			parent: null,
-			effect: null,
-			effects: [],
-			render_effects: []
-		};
+		/** @type {Effect[]} */
+		var effects = [];
+
+		/** @type {Effect[]} */
+		var render_effects = [];
 
 		for (const root of root_effects) {
-			this.#traverse_effect_tree(root, target);
+			this.#traverse_effect_tree(root, effects, render_effects);
 			// Note: #traverse_effect_tree runs block effects eagerly, which can schedule effects,
 			// which means queued_root_effects now may be filled again.
 
@@ -183,16 +173,16 @@ export class Batch {
 		}
 
 		if (this.is_deferred()) {
-			this.#defer_effects(target.effects);
-			this.#defer_effects(target.render_effects);
+			this.#defer_effects(render_effects);
+			this.#defer_effects(effects);
 		} else {
 			// If sources are written to, then work needs to happen in a separate batch, else prior sources would be mixed with
 			// newly updated sources, which could lead to infinite loops when effects run over and over again.
 			previous_batch = this;
 			current_batch = null;
 
-			flush_queued_effects(target.render_effects);
-			flush_queued_effects(target.effects);
+			flush_queued_effects(render_effects);
+			flush_queued_effects(effects);
 
 			previous_batch = null;
 
@@ -206,13 +196,17 @@ export class Batch {
 	 * Traverse the effect tree, executing effects or stashing
 	 * them for later execution as appropriate
 	 * @param {Effect} root
-	 * @param {EffectTarget} target
+	 * @param {Effect[]} effects
+	 * @param {Effect[]} render_effects
 	 */
-	#traverse_effect_tree(root, target) {
+	#traverse_effect_tree(root, effects, render_effects) {
 		root.f ^= CLEAN;
 
 		var effect = root.first;
 
+		/** @type {Effect | null} */
+		var pending_boundary = null;
+
 		while (effect !== null) {
 			var flags = effect.f;
 			var is_branch = (flags & (BRANCH_EFFECT | ROOT_EFFECT)) !== 0;
@@ -220,24 +214,32 @@ export class Batch {
 
 			var skip = is_skippable_branch || (flags & INERT) !== 0 || this.skipped_effects.has(effect);
 
-			if ((effect.f & BOUNDARY_EFFECT) !== 0 && effect.b?.is_pending()) {
-				target = {
-					parent: target,
-					effect,
-					effects: [],
-					render_effects: []
-				};
+			// Inside a `<svelte:boundary>` with a pending snippet,
+			// all effects are deferred until the boundary resolves
+			// (except block/async effects, which run immediately)
+			if (
+				async_mode_flag &&
+				pending_boundary === null &&
+				(flags & BOUNDARY_EFFECT) !== 0 &&
+				effect.b?.is_pending
+			) {
+				pending_boundary = effect;
 			}
 
 			if (!skip && effect.fn !== null) {
 				if (is_branch) {
 					effect.f ^= CLEAN;
+				} else if (
+					pending_boundary !== null &&
+					(flags & (EFFECT | RENDER_EFFECT | MANAGED_EFFECT)) !== 0
+				) {
+					/** @type {Boundary} */ (pending_boundary.b).defer_effect(effect);
 				} else if ((flags & EFFECT) !== 0) {
-					target.effects.push(effect);
+					effects.push(effect);
 				} else if (async_mode_flag && (flags & (RENDER_EFFECT | MANAGED_EFFECT)) !== 0) {
-					target.render_effects.push(effect);
+					render_effects.push(effect);
 				} else if (is_dirty(effect)) {
-					if ((effect.f & BLOCK_EFFECT) !== 0) this.#dirty_effects.add(effect);
+					if ((flags & BLOCK_EFFECT) !== 0) this.#dirty_effects.add(effect);
 					update_effect(effect);
 				}
 
@@ -253,14 +255,8 @@ export class Batch {
 			effect = effect.next;
 
 			while (effect === null && parent !== null) {
-				if (parent === target.effect) {
-					// TODO rather than traversing into pending boundaries and deferring the effects,
-					// could we just attach the effects _to_ the pending boundary and schedule them
-					// once the boundary is ready?
-					this.#defer_effects(target.effects);
-					this.#defer_effects(target.render_effects);
-
-					target = /** @type {EffectTarget} */ (target.parent);
+				if (parent === pending_boundary) {
+					pending_boundary = null;
 				}
 
 				effect = parent.next;
@@ -273,36 +269,8 @@ export class Batch {
 	 * @param {Effect[]} effects
 	 */
 	#defer_effects(effects) {
-		for (const e of effects) {
-			if ((e.f & DIRTY) !== 0) {
-				this.#dirty_effects.add(e);
-			} else if ((e.f & MAYBE_DIRTY) !== 0) {
-				this.#maybe_dirty_effects.add(e);
-			}
-
-			// Since we're not executing these effects now, we need to clear any WAS_MARKED flags
-			// so that other batches can correctly reach these effects during their own traversal
-			this.#clear_marked(e.deps);
-
-			// mark as clean so they get scheduled if they depend on pending async state
-			set_signal_status(e, CLEAN);
-		}
-	}
-
-	/**
-	 * @param {Value[] | null} deps
-	 */
-	#clear_marked(deps) {
-		if (deps === null) return;
-
-		for (const dep of deps) {
-			if ((dep.f & DERIVED) === 0 || (dep.f & WAS_MARKED) === 0) {
-				continue;
-			}
-
-			dep.f ^= WAS_MARKED;
-
-			this.#clear_marked(/** @type {Derived} */ (dep).deps);
+		for (var i = 0; i < effects.length; i += 1) {
+			defer_effect(effects[i], this.#dirty_effects, this.#maybe_dirty_effects);
 		}
 	}
 
@@ -383,14 +351,6 @@ export class Batch {
 			var previous_batch_values = batch_values;
 			var is_earlier = true;
 
-			/** @type {EffectTarget} */
-			var dummy_target = {
-				parent: null,
-				effect: null,
-				effects: [],
-				render_effects: []
-			};
-
 			for (const batch of batches) {
 				if (batch === this) {
 					is_earlier = false;
@@ -439,10 +399,10 @@ export class Batch {
 						batch.apply();
 
 						for (const root of queued_root_effects) {
-							batch.#traverse_effect_tree(root, dummy_target);
+							batch.#traverse_effect_tree(root, [], []);
 						}
 
-						// TODO do we need to do anything with `target`? defer block effects?
+						// TODO do we need to do anything with the dummy effect arrays?
 
 						batch.deactivate();
 					}
diff --git a/packages/svelte/src/internal/client/reactivity/deriveds.js b/packages/svelte/src/internal/client/reactivity/deriveds.js
index ee8ba29c21..9dc324d3f9 100644
--- a/packages/svelte/src/internal/client/reactivity/deriveds.js
+++ b/packages/svelte/src/internal/client/reactivity/deriveds.js
@@ -150,7 +150,7 @@ export function async_derived(fn, label, location) {
 		var batch = /** @type {Batch} */ (current_batch);
 
 		if (should_suspend) {
-			var blocking = !boundary.is_pending();
+			var blocking = boundary.is_rendered();
 
 			boundary.update_pending_count(1);
 			batch.increment(blocking);
diff --git a/packages/svelte/src/internal/client/reactivity/utils.js b/packages/svelte/src/internal/client/reactivity/utils.js
new file mode 100644
index 0000000000..0dd6b3212d
--- /dev/null
+++ b/packages/svelte/src/internal/client/reactivity/utils.js
@@ -0,0 +1,40 @@
+/** @import { Derived, Effect, Value } from '#client' */
+import { CLEAN, DERIVED, DIRTY, MAYBE_DIRTY, WAS_MARKED } from '#client/constants';
+import { set_signal_status } from '../runtime.js';
+
+/**
+ * @param {Value[] | null} deps
+ */
+function clear_marked(deps) {
+	if (deps === null) return;
+
+	for (const dep of deps) {
+		if ((dep.f & DERIVED) === 0 || (dep.f & WAS_MARKED) === 0) {
+			continue;
+		}
+
+		dep.f ^= WAS_MARKED;
+
+		clear_marked(/** @type {Derived} */ (dep).deps);
+	}
+}
+
+/**
+ * @param {Effect} effect
+ * @param {Set<Effect>} dirty_effects
+ * @param {Set<Effect>} maybe_dirty_effects
+ */
+export function defer_effect(effect, dirty_effects, maybe_dirty_effects) {
+	if ((effect.f & DIRTY) !== 0) {
+		dirty_effects.add(effect);
+	} else if ((effect.f & MAYBE_DIRTY) !== 0) {
+		maybe_dirty_effects.add(effect);
+	}
+
+	// Since we're not executing these effects now, we need to clear any WAS_MARKED flags
+	// so that other batches can correctly reach these effects during their own traversal
+	clear_marked(effect.deps);
+
+	// mark as clean so they get scheduled if they depend on pending async state
+	set_signal_status(effect, CLEAN);
+}
diff --git a/packages/svelte/tests/runtime-runes/samples/async-clear-batch-between-runs/Child.svelte b/packages/svelte/tests/runtime-runes/samples/async-clear-batch-between-runs/Child.svelte
new file mode 100644
index 0000000000..d156cc99af
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-clear-batch-between-runs/Child.svelte
@@ -0,0 +1,15 @@
+<script>
+	let { x, y, deferred } = $props();
+
+	y = await deferred.promise;
+</script>
+
+<p>x: {x}</p>
+
+<svelte:boundary>
+	{#snippet pending()}
+		<p>Loading...</p>
+	{/snippet}
+
+	<p>y: {y}</p>
+</svelte:boundary>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-clear-batch-between-runs/_config.js b/packages/svelte/tests/runtime-runes/samples/async-clear-batch-between-runs/_config.js
new file mode 100644
index 0000000000..fbf003f8e2
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-clear-batch-between-runs/_config.js
@@ -0,0 +1,32 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	html: `
+		<button>x</button>
+		<button>y</button>
+		<p>loading...</p>
+	`,
+
+	async test({ assert, target }) {
+		await tick();
+
+		const [button1, button2] = target.querySelectorAll('button');
+
+		button1.click();
+		await tick();
+
+		button2.click();
+		await tick();
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>x</button>
+				<button>y</button>
+				<p>x: x2</p>
+				<p>y: y2</p>
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-clear-batch-between-runs/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-clear-batch-between-runs/main.svelte
new file mode 100644
index 0000000000..57ab32a6ca
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-clear-batch-between-runs/main.svelte
@@ -0,0 +1,19 @@
+<script>
+	import Child from './Child.svelte';
+
+	let x = $state('x1');
+	let y = $state('y1');
+
+	const deferred = Promise.withResolvers();
+</script>
+
+<button onclick={() => x = 'x2'}>x</button>
+<button onclick={() => deferred.resolve('y2')}>y</button>
+
+<svelte:boundary>
+	<Child {x} {y} {deferred} />
+
+	{#snippet pending()}
+		<p>loading...</p>
+	{/snippet}
+</svelte:boundary>

From 044dce9da54cdf2dc1c8d268038364c4ac22b110 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 7 Jan 2026 18:37:01 +0000
Subject: [PATCH 018/142] fix: adjust `loc` property of `Program` nodes created
 from `<script>` elements (#17428)

* fix: adjust program location to prevent corrupted sourcemaps

* update changeset

* go the other way
---
 .changeset/tall-phones-fix.md                            | 5 +++++
 .../svelte/src/compiler/phases/1-parse/read/script.js    | 9 ++++++++-
 .../parser-legacy/samples/binding-shorthand/output.json  | 2 +-
 .../tests/parser-legacy/samples/binding/output.json      | 2 +-
 .../parser-legacy/samples/dynamic-import/output.json     | 2 +-
 .../samples/each-block-destructured/output.json          | 2 +-
 .../parser-legacy/samples/generic-snippets/output.json   | 2 +-
 .../samples/javascript-comments/output.json              | 2 +-
 .../svelte/tests/parser-legacy/samples/refs/output.json  | 2 +-
 .../script-attribute-with-curly-braces/output.json       | 2 +-
 .../samples/script-comment-only/output.json              | 2 +-
 .../samples/script-context-module-unquoted/output.json   | 6 +++---
 .../tests/parser-legacy/samples/script/output.json       | 2 +-
 .../samples/whitespace-after-script-tag/output.json      | 4 ++--
 .../samples/comment-before-function-binding/output.json  | 2 +-
 .../samples/comment-before-script/output.json            | 4 ++--
 .../parser-modern/samples/generic-snippets/output.json   | 2 +-
 .../samples/loose-valid-each-as/output.json              | 2 +-
 .../tests/parser-modern/samples/options/output.json      | 8 ++++----
 .../samples/script-style-no-markup/output.json           | 2 +-
 .../tests/parser-modern/samples/snippets/output.json     | 2 +-
 .../samples/typescript-in-event-handler/output.json      | 2 +-
 22 files changed, 40 insertions(+), 28 deletions(-)
 create mode 100644 .changeset/tall-phones-fix.md

diff --git a/.changeset/tall-phones-fix.md b/.changeset/tall-phones-fix.md
new file mode 100644
index 0000000000..29e57c060f
--- /dev/null
+++ b/.changeset/tall-phones-fix.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: adjust `loc` property of `Program` nodes created from `<script>` elements
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 9ce449f200..db3c50a8d1 100644
--- a/packages/svelte/src/compiler/phases/1-parse/read/script.js
+++ b/packages/svelte/src/compiler/phases/1-parse/read/script.js
@@ -6,6 +6,7 @@ import { regex_not_newline_characters } from '../../patterns.js';
 import * as e from '../../../errors.js';
 import * as w from '../../../warnings.js';
 import { is_text_attribute } from '../../../utils/ast.js';
+import { locator } from '../../../state.js';
 
 const regex_closing_script_tag = /<\/script\s*>/;
 const regex_starts_with_closing_script_tag = /^<\/script\s*>/;
@@ -39,9 +40,15 @@ export function read_script(parser, start, attributes) {
 		parser.acorn_error(err);
 	}
 
-	// TODO is this necessary?
 	ast.start = script_start;
 
+	if (ast.loc) {
+		// Acorn always uses `0` as the start of a `Program`, but for sourcemap purposes
+		// we need it to be the start of the `<script>` contents
+		({ line: ast.loc.start.line, column: ast.loc.start.column } = locator(start));
+		({ line: ast.loc.end.line, column: ast.loc.end.column } = locator(parser.index));
+	}
+
 	/** @type {'default' | 'module'} */
 	let context = 'default';
 
diff --git a/packages/svelte/tests/parser-legacy/samples/binding-shorthand/output.json b/packages/svelte/tests/parser-legacy/samples/binding-shorthand/output.json
index 9c48025ff9..711bd54525 100644
--- a/packages/svelte/tests/parser-legacy/samples/binding-shorthand/output.json
+++ b/packages/svelte/tests/parser-legacy/samples/binding-shorthand/output.json
@@ -63,7 +63,7 @@
 				},
 				"end": {
 					"line": 3,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [
diff --git a/packages/svelte/tests/parser-legacy/samples/binding/output.json b/packages/svelte/tests/parser-legacy/samples/binding/output.json
index 17a78f051c..b103e03683 100644
--- a/packages/svelte/tests/parser-legacy/samples/binding/output.json
+++ b/packages/svelte/tests/parser-legacy/samples/binding/output.json
@@ -73,7 +73,7 @@
 				},
 				"end": {
 					"line": 3,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [
diff --git a/packages/svelte/tests/parser-legacy/samples/dynamic-import/output.json b/packages/svelte/tests/parser-legacy/samples/dynamic-import/output.json
index ee19d58742..76bb6c7eb6 100644
--- a/packages/svelte/tests/parser-legacy/samples/dynamic-import/output.json
+++ b/packages/svelte/tests/parser-legacy/samples/dynamic-import/output.json
@@ -21,7 +21,7 @@
 				},
 				"end": {
 					"line": 9,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [
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 637da24aea..684051e304 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
@@ -190,7 +190,7 @@
 				},
 				"end": {
 					"line": 3,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [
diff --git a/packages/svelte/tests/parser-legacy/samples/generic-snippets/output.json b/packages/svelte/tests/parser-legacy/samples/generic-snippets/output.json
index 9cb5d765e8..76605f5192 100644
--- a/packages/svelte/tests/parser-legacy/samples/generic-snippets/output.json
+++ b/packages/svelte/tests/parser-legacy/samples/generic-snippets/output.json
@@ -258,7 +258,7 @@
 				},
 				"end": {
 					"line": 2,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [],
diff --git a/packages/svelte/tests/parser-legacy/samples/javascript-comments/output.json b/packages/svelte/tests/parser-legacy/samples/javascript-comments/output.json
index 4723564f17..3775c48228 100644
--- a/packages/svelte/tests/parser-legacy/samples/javascript-comments/output.json
+++ b/packages/svelte/tests/parser-legacy/samples/javascript-comments/output.json
@@ -298,7 +298,7 @@
 				},
 				"end": {
 					"line": 31,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [
diff --git a/packages/svelte/tests/parser-legacy/samples/refs/output.json b/packages/svelte/tests/parser-legacy/samples/refs/output.json
index 7f30946fc5..1e8efe78f8 100644
--- a/packages/svelte/tests/parser-legacy/samples/refs/output.json
+++ b/packages/svelte/tests/parser-legacy/samples/refs/output.json
@@ -73,7 +73,7 @@
 				},
 				"end": {
 					"line": 3,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [
diff --git a/packages/svelte/tests/parser-legacy/samples/script-attribute-with-curly-braces/output.json b/packages/svelte/tests/parser-legacy/samples/script-attribute-with-curly-braces/output.json
index e0b50e3b92..4ad004c88a 100644
--- a/packages/svelte/tests/parser-legacy/samples/script-attribute-with-curly-braces/output.json
+++ b/packages/svelte/tests/parser-legacy/samples/script-attribute-with-curly-braces/output.json
@@ -73,7 +73,7 @@
 				},
 				"end": {
 					"line": 3,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [
diff --git a/packages/svelte/tests/parser-legacy/samples/script-comment-only/output.json b/packages/svelte/tests/parser-legacy/samples/script-comment-only/output.json
index b04a823e8d..0f7d0b8465 100644
--- a/packages/svelte/tests/parser-legacy/samples/script-comment-only/output.json
+++ b/packages/svelte/tests/parser-legacy/samples/script-comment-only/output.json
@@ -37,7 +37,7 @@
 				},
 				"end": {
 					"line": 3,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [],
diff --git a/packages/svelte/tests/parser-legacy/samples/script-context-module-unquoted/output.json b/packages/svelte/tests/parser-legacy/samples/script-context-module-unquoted/output.json
index 64250cb302..34a640200c 100644
--- a/packages/svelte/tests/parser-legacy/samples/script-context-module-unquoted/output.json
+++ b/packages/svelte/tests/parser-legacy/samples/script-context-module-unquoted/output.json
@@ -24,12 +24,12 @@
 			"end": 77,
 			"loc": {
 				"start": {
-					"line": 1,
+					"line": 5,
 					"column": 0
 				},
 				"end": {
 					"line": 7,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [
@@ -84,7 +84,7 @@
 				},
 				"end": {
 					"line": 3,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [
diff --git a/packages/svelte/tests/parser-legacy/samples/script/output.json b/packages/svelte/tests/parser-legacy/samples/script/output.json
index d3d4abd6b2..14d2805216 100644
--- a/packages/svelte/tests/parser-legacy/samples/script/output.json
+++ b/packages/svelte/tests/parser-legacy/samples/script/output.json
@@ -73,7 +73,7 @@
 				},
 				"end": {
 					"line": 3,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [
diff --git a/packages/svelte/tests/parser-legacy/samples/whitespace-after-script-tag/output.json b/packages/svelte/tests/parser-legacy/samples/whitespace-after-script-tag/output.json
index 69b2382442..8853c32f9c 100644
--- a/packages/svelte/tests/parser-legacy/samples/whitespace-after-script-tag/output.json
+++ b/packages/svelte/tests/parser-legacy/samples/whitespace-after-script-tag/output.json
@@ -72,8 +72,8 @@
 					"column": 0
 				},
 				"end": {
-					"line": 3,
-					"column": 0
+					"line": 8,
+					"column": 1
 				}
 			},
 			"body": [
diff --git a/packages/svelte/tests/parser-modern/samples/comment-before-function-binding/output.json b/packages/svelte/tests/parser-modern/samples/comment-before-function-binding/output.json
index 13cc5fea7b..27692e98b4 100644
--- a/packages/svelte/tests/parser-modern/samples/comment-before-function-binding/output.json
+++ b/packages/svelte/tests/parser-modern/samples/comment-before-function-binding/output.json
@@ -272,7 +272,7 @@
 				},
 				"end": {
 					"line": 3,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [
diff --git a/packages/svelte/tests/parser-modern/samples/comment-before-script/output.json b/packages/svelte/tests/parser-modern/samples/comment-before-script/output.json
index 8d77165297..8840aad85a 100644
--- a/packages/svelte/tests/parser-modern/samples/comment-before-script/output.json
+++ b/packages/svelte/tests/parser-modern/samples/comment-before-script/output.json
@@ -34,12 +34,12 @@
 			"end": 67,
 			"loc": {
 				"start": {
-					"line": 1,
+					"line": 2,
 					"column": 0
 				},
 				"end": {
 					"line": 4,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [
diff --git a/packages/svelte/tests/parser-modern/samples/generic-snippets/output.json b/packages/svelte/tests/parser-modern/samples/generic-snippets/output.json
index 8e1654feed..f29eb6fc72 100644
--- a/packages/svelte/tests/parser-modern/samples/generic-snippets/output.json
+++ b/packages/svelte/tests/parser-modern/samples/generic-snippets/output.json
@@ -296,7 +296,7 @@
 				},
 				"end": {
 					"line": 2,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [],
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 b428cff0b2..441cf71519 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
@@ -227,7 +227,7 @@
 				},
 				"end": {
 					"line": 3,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [
diff --git a/packages/svelte/tests/parser-modern/samples/options/output.json b/packages/svelte/tests/parser-modern/samples/options/output.json
index 08ce8d43b7..c220811175 100644
--- a/packages/svelte/tests/parser-modern/samples/options/output.json
+++ b/packages/svelte/tests/parser-modern/samples/options/output.json
@@ -111,12 +111,12 @@
 			"end": 93,
 			"loc": {
 				"start": {
-					"line": 1,
+					"line": 3,
 					"column": 0
 				},
 				"end": {
 					"line": 4,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [],
@@ -182,12 +182,12 @@
 			"end": 160,
 			"loc": {
 				"start": {
-					"line": 1,
+					"line": 6,
 					"column": 0
 				},
 				"end": {
 					"line": 7,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [],
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 b5e42e9217..db58a62148 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
@@ -93,7 +93,7 @@
 				},
 				"end": {
 					"line": 3,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [],
diff --git a/packages/svelte/tests/parser-modern/samples/snippets/output.json b/packages/svelte/tests/parser-modern/samples/snippets/output.json
index c217ef94e9..f358e2a60c 100644
--- a/packages/svelte/tests/parser-modern/samples/snippets/output.json
+++ b/packages/svelte/tests/parser-modern/samples/snippets/output.json
@@ -230,7 +230,7 @@
 				},
 				"end": {
 					"line": 1,
-					"column": 18
+					"column": 27
 				}
 			},
 			"body": [],
diff --git a/packages/svelte/tests/parser-modern/samples/typescript-in-event-handler/output.json b/packages/svelte/tests/parser-modern/samples/typescript-in-event-handler/output.json
index a1d6ed56bf..7b521513f4 100644
--- a/packages/svelte/tests/parser-modern/samples/typescript-in-event-handler/output.json
+++ b/packages/svelte/tests/parser-modern/samples/typescript-in-event-handler/output.json
@@ -396,7 +396,7 @@
 				},
 				"end": {
 					"line": 3,
-					"column": 0
+					"column": 9
 				}
 			},
 			"body": [

From ac7c7646bcee53870dd96e9174728ffa1d63411d Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Thu, 8 Jan 2026 09:10:13 -0500
Subject: [PATCH 019/142] fix: don't transform references of function
 declarations in legacy mode (#17431)

---
 .changeset/better-games-invite.md                     |  5 +++++
 .../svelte/src/compiler/phases/2-analyze/index.js     |  3 ++-
 .../compiler/phases/2-analyze/visitors/EachBlock.js   |  4 +++-
 .../samples/binding-indirect-fn/_config.js            |  7 +++++++
 .../samples/binding-indirect-fn/main.svelte           | 11 +++++++++++
 5 files changed, 28 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/better-games-invite.md
 create mode 100644 packages/svelte/tests/runtime-legacy/samples/binding-indirect-fn/_config.js
 create mode 100644 packages/svelte/tests/runtime-legacy/samples/binding-indirect-fn/main.svelte

diff --git a/.changeset/better-games-invite.md b/.changeset/better-games-invite.md
new file mode 100644
index 0000000000..8361a1e9bb
--- /dev/null
+++ b/.changeset/better-games-invite.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: don't transform references of function declarations in legacy mode
diff --git a/packages/svelte/src/compiler/phases/2-analyze/index.js b/packages/svelte/src/compiler/phases/2-analyze/index.js
index 6d23e4d265..ef0b35f560 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/index.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/index.js
@@ -657,7 +657,8 @@ export function analyze_component(root, source, options) {
 									if (
 										binding &&
 										binding.kind === 'normal' &&
-										binding.declaration_kind !== 'import'
+										binding.declaration_kind !== 'import' &&
+										binding.declaration_kind !== 'function'
 									) {
 										binding.kind = 'state';
 										binding.mutated = true;
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/EachBlock.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/EachBlock.js
index 81a9c1e2d1..5681966475 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/EachBlock.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/EachBlock.js
@@ -54,7 +54,9 @@ export function EachBlock(node, context) {
 
 		// collect transitive dependencies...
 		for (const binding of node.metadata.expression.dependencies) {
-			collect_transitive_dependencies(binding, node.metadata.transitive_deps);
+			if (binding.declaration_kind !== 'function') {
+				collect_transitive_dependencies(binding, node.metadata.transitive_deps);
+			}
 		}
 
 		// ...and ensure they are marked as state, so they can be turned
diff --git a/packages/svelte/tests/runtime-legacy/samples/binding-indirect-fn/_config.js b/packages/svelte/tests/runtime-legacy/samples/binding-indirect-fn/_config.js
new file mode 100644
index 0000000000..f17a7f4825
--- /dev/null
+++ b/packages/svelte/tests/runtime-legacy/samples/binding-indirect-fn/_config.js
@@ -0,0 +1,7 @@
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		assert.htmlEqual(target.innerHTML, `<input>`);
+	}
+});
diff --git a/packages/svelte/tests/runtime-legacy/samples/binding-indirect-fn/main.svelte b/packages/svelte/tests/runtime-legacy/samples/binding-indirect-fn/main.svelte
new file mode 100644
index 0000000000..9c1e23a0f4
--- /dev/null
+++ b/packages/svelte/tests/runtime-legacy/samples/binding-indirect-fn/main.svelte
@@ -0,0 +1,11 @@
+<script>
+  $: items = [{ value: 'hello' }];
+
+  function fn(value) {
+		return true;
+	}
+</script>
+
+{#each items.filter(fn) as item}
+  <input bind:value={item.value} />
+{/each}

From 05a85d305a19f4c71e6dbfa5f967697234f180f1 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Thu, 8 Jan 2026 13:15:12 -0500
Subject: [PATCH 020/142] chore: use normalization helper for hydration tests
 (#17434)

---
 packages/svelte/tests/hydration/test.ts | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/packages/svelte/tests/hydration/test.ts b/packages/svelte/tests/hydration/test.ts
index ba13d2c611..d7257c71d3 100644
--- a/packages/svelte/tests/hydration/test.ts
+++ b/packages/svelte/tests/hydration/test.ts
@@ -131,19 +131,12 @@ const { test, run } = suite<HydrationTest>(async (config, cwd) => {
 
 		flushSync();
 
-		const normalize = (string: string) =>
-			string
-				.trim()
-				.replaceAll('\r\n', '\n')
-				.replaceAll('/>', '>')
-				.replace(/<!--.+?-->/g, '');
-
 		const expected = read(`${cwd}/_expected.html`) ?? rendered.html;
-		assert.equal(normalize(target.innerHTML), normalize(expected));
+		assert_html_equal(target.innerHTML, expected);
 
 		if (rendered.head) {
 			const expected = read(`${cwd}/_expected_head.html`) ?? rendered.head;
-			assert.equal(normalize(head.innerHTML), normalize(expected));
+			assert_html_equal(head.innerHTML, expected);
 		}
 
 		if (config.snapshot) {

From 4f49ea896129091175f1945f67fcb29d28ef8d0c Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Thu, 8 Jan 2026 15:15:13 -0500
Subject: [PATCH 021/142] fix: don't revert source to UNINITIALIZED state when
 time travelling (#17409)

* add failing test

* WIP

* remove comment

* changeset

* fix: clear batch between runs

* changeset

* fix

* unused
---
 .changeset/thick-islands-pull.md              |  5 ++++
 .../internal/client/dom/blocks/boundary.js    |  8 +++---
 .../src/internal/client/reactivity/batch.js   |  3 ++-
 .../_config.js                                | 18 +++++++++++++
 .../main.svelte                               | 25 +++++++++++++++++++
 5 files changed, 54 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/thick-islands-pull.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-derived-with-effect-and-boundary/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-derived-with-effect-and-boundary/main.svelte

diff --git a/.changeset/thick-islands-pull.md b/.changeset/thick-islands-pull.md
new file mode 100644
index 0000000000..f987d72260
--- /dev/null
+++ b/.changeset/thick-islands-pull.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: don't revert source to UNINITIALIZED state when time travelling
diff --git a/packages/svelte/src/internal/client/dom/blocks/boundary.js b/packages/svelte/src/internal/client/dom/blocks/boundary.js
index 92f4c0a104..cc4bc34e7b 100644
--- a/packages/svelte/src/internal/client/dom/blocks/boundary.js
+++ b/packages/svelte/src/internal/client/dom/blocks/boundary.js
@@ -161,6 +161,10 @@ export class Boundary {
 					this.#hydrate_pending_content();
 				} else {
 					this.#hydrate_resolved_content();
+
+					if (this.#pending_count === 0) {
+						this.is_pending = false;
+					}
 				}
 			} else {
 				var anchor = this.#get_anchor();
@@ -194,10 +198,6 @@ export class Boundary {
 		} catch (error) {
 			this.error(error);
 		}
-
-		// Since server rendered resolved content, we never show pending state
-		// Even if client-side async operations are still running, the content is already displayed
-		this.is_pending = false;
 	}
 
 	#hydrate_pending_content() {
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 6dd90ba1b4..d6d23dc9c5 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -38,6 +38,7 @@ 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 { defer_effect } from './utils.js';
+import { UNINITIALIZED } from '../../../constants.js';
 
 /** @type {Set<Batch>} */
 const batches = new Set();
@@ -281,7 +282,7 @@ export class Batch {
 	 * @param {any} value
 	 */
 	capture(source, value) {
-		if (!this.previous.has(source)) {
+		if (value !== UNINITIALIZED && !this.previous.has(source)) {
 			this.previous.set(source, value);
 		}
 
diff --git a/packages/svelte/tests/runtime-runes/samples/async-derived-with-effect-and-boundary/_config.js b/packages/svelte/tests/runtime-runes/samples/async-derived-with-effect-and-boundary/_config.js
new file mode 100644
index 0000000000..49428f90ad
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-derived-with-effect-and-boundary/_config.js
@@ -0,0 +1,18 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	skip_no_async: true,
+
+	async test({ assert, target }) {
+		await tick();
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<p>baz: 69</p>
+				<p></p>
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-derived-with-effect-and-boundary/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-derived-with-effect-and-boundary/main.svelte
new file mode 100644
index 0000000000..0e05d0c414
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-derived-with-effect-and-boundary/main.svelte
@@ -0,0 +1,25 @@
+<script>
+	let foo = $state(null);
+
+	$effect(() => {
+		foo = 69;
+	});
+
+	let bar = $derived(await 1);
+
+	let baz = $derived(foo ? foo * bar : null);
+
+	const qux = "qux";
+</script>
+
+<p>baz: {baz}</p>
+
+<svelte:boundary>
+	{#snippet pending()}
+		<p>Loading...</p>
+	{/snippet}
+
+	{#if qux}
+		<p></p>
+	{/if}
+</svelte:boundary>

From 7ad5772309dc27313ff044b183e44b67e8e14d2b Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Thu, 8 Jan 2026 17:28:30 -0500
Subject: [PATCH 022/142] fix: notify deriveds of changes to sources inside
 forks (#17437)

* failing tests

* update tests

* update write versions when committing forks

* remove second test, for now

* changeset

* fix: correctly update writable deriveds inside forks (#17438)

* fix: correctly update writable deriveds inside forks

* tweak

* changeset

* on second thoughts, minimise the diff, and revisit later

* missed a spot
---
 .changeset/empty-paths-smile.md               |  5 +++++
 .changeset/seven-llamas-care.md               |  5 +++++
 .../src/internal/client/reactivity/batch.js   | 13 ++++++++---
 .../async-fork-derived-writable/_config.js    | 14 ++++++++++++
 .../async-fork-derived-writable/main.svelte   | 22 +++++++++++++++++++
 .../samples/async-fork-derived/_config.js     | 16 ++++++++++++++
 .../samples/async-fork-derived/main.svelte    | 16 ++++++++++++++
 7 files changed, 88 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/empty-paths-smile.md
 create mode 100644 .changeset/seven-llamas-care.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-fork-derived-writable/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-fork-derived-writable/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-fork-derived/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-fork-derived/main.svelte

diff --git a/.changeset/empty-paths-smile.md b/.changeset/empty-paths-smile.md
new file mode 100644
index 0000000000..687ad19b24
--- /dev/null
+++ b/.changeset/empty-paths-smile.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: notify deriveds of changes to sources inside forks
diff --git a/.changeset/seven-llamas-care.md b/.changeset/seven-llamas-care.md
new file mode 100644
index 0000000000..1b41b4848a
--- /dev/null
+++ b/.changeset/seven-llamas-care.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: correctly update writable deriveds inside forks
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index d6d23dc9c5..9b80df34e4 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -25,6 +25,7 @@ import { deferred, define_property } from '../../shared/utils.js';
 import {
 	active_effect,
 	get,
+	increment_write_version,
 	is_dirty,
 	is_updating_effect,
 	set_is_updating_effect,
@@ -920,13 +921,18 @@ export function fork(fn) {
 
 	flushSync(fn);
 
-	batch_values = null;
-
 	// revert state changes
 	for (var [source, value] of batch.previous) {
 		source.v = value;
 	}
 
+	// make writable deriveds dirty, so they recalculate correctly
+	for (source of batch.current.keys()) {
+		if ((source.f & DERIVED) !== 0) {
+			set_signal_status(source, DIRTY);
+		}
+	}
+
 	return {
 		commit: async () => {
 			if (committed) {
@@ -942,9 +948,10 @@ export function fork(fn) {
 
 			batch.is_fork = false;
 
-			// apply changes
+			// apply changes and update write versions so deriveds see the change
 			for (var [source, value] of batch.current) {
 				source.v = value;
+				source.wv = increment_write_version();
 			}
 
 			// trigger any `$state.eager(...)` expressions with the new state.
diff --git a/packages/svelte/tests/runtime-runes/samples/async-fork-derived-writable/_config.js b/packages/svelte/tests/runtime-runes/samples/async-fork-derived-writable/_config.js
new file mode 100644
index 0000000000..b089b714ec
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-fork-derived-writable/_config.js
@@ -0,0 +1,14 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target, logs }) {
+		const [btn] = target.querySelectorAll('button');
+
+		btn.click();
+		await tick();
+		// d should be 10 (real-world: s=1, d=1*10) before commit, not 20 (fork: s=2, d=2*10)
+		// After commit, d should be 99 (the written value)
+		assert.deepEqual(logs, [10, 99]);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-fork-derived-writable/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-fork-derived-writable/main.svelte
new file mode 100644
index 0000000000..bc118a558a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-fork-derived-writable/main.svelte
@@ -0,0 +1,22 @@
+<script>
+	import { fork } from 'svelte';
+
+	let s = $state(1);
+	let d = $derived(s * 10);
+</script>
+
+<button onclick={async () => {
+	const f = fork(() => {
+		// First modify s, then write to d
+		// If d is evaluated in fork context, it would see s=2 and compute d=20
+		// But it should evaluate in real-world context to get d=10
+		s = 2;
+		d = 99;
+	});
+
+	// Should be 10 (real-world value: s=1, so d=1*10=10), not 20 (fork value)
+	console.log(d);
+	await f.commit();
+	// Should be 99 (the value we wrote)
+	console.log(d);
+}}>++</button>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-fork-derived/_config.js b/packages/svelte/tests/runtime-runes/samples/async-fork-derived/_config.js
new file mode 100644
index 0000000000..59ae376167
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-fork-derived/_config.js
@@ -0,0 +1,16 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target, logs }) {
+		const [increment] = target.querySelectorAll('button');
+
+		increment.click();
+		await tick();
+		assert.deepEqual(logs, [1, 2]);
+
+		increment.click();
+		await tick();
+		assert.deepEqual(logs, [1, 2, 2, 3]);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-fork-derived/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-fork-derived/main.svelte
new file mode 100644
index 0000000000..93761869d6
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-fork-derived/main.svelte
@@ -0,0 +1,16 @@
+<script>
+	import { fork } from 'svelte';
+
+	let s = $state(1);
+	let d = $derived(s);
+</script>
+
+<button onclick={async () => {
+	const f = fork(() => {
+		s = s + 1;
+	});
+
+	console.log(d);
+	await f.commit();
+	console.log(d);
+}}>++</button>

From c6ce1ffeffe1ecff45611b8ec4e653836f113b5d Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 9 Jan 2026 12:13:29 -0500
Subject: [PATCH 023/142] chore: move set_signal_status into separate module
 (#17441)

---
 .../src/internal/client/dom/blocks/boundary.js       |  4 ++--
 .../svelte/src/internal/client/reactivity/batch.js   |  2 +-
 .../src/internal/client/reactivity/deriveds.js       |  2 +-
 .../svelte/src/internal/client/reactivity/effects.js |  2 +-
 .../svelte/src/internal/client/reactivity/sources.js |  2 +-
 .../svelte/src/internal/client/reactivity/status.js  | 12 ++++++++++++
 .../svelte/src/internal/client/reactivity/utils.js   |  2 +-
 packages/svelte/src/internal/client/runtime.js       | 12 +-----------
 packages/svelte/src/legacy/legacy-client.js          |  3 ++-
 9 files changed, 22 insertions(+), 19 deletions(-)
 create mode 100644 packages/svelte/src/internal/client/reactivity/status.js

diff --git a/packages/svelte/src/internal/client/dom/blocks/boundary.js b/packages/svelte/src/internal/client/dom/blocks/boundary.js
index cc4bc34e7b..61262a6576 100644
--- a/packages/svelte/src/internal/client/dom/blocks/boundary.js
+++ b/packages/svelte/src/internal/client/dom/blocks/boundary.js
@@ -22,8 +22,7 @@ import {
 	active_reaction,
 	get,
 	set_active_effect,
-	set_active_reaction,
-	set_signal_status
+	set_active_reaction
 } from '../../runtime.js';
 import {
 	hydrate_next,
@@ -43,6 +42,7 @@ import { tag } from '../../dev/tracing.js';
 import { createSubscriber } from '../../../../reactivity/create-subscriber.js';
 import { create_text } from '../operations.js';
 import { defer_effect } from '../../reactivity/utils.js';
+import { set_signal_status } from '../../reactivity/status.js';
 
 /**
  * @typedef {{
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 9b80df34e4..4c50781817 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -29,7 +29,6 @@ import {
 	is_dirty,
 	is_updating_effect,
 	set_is_updating_effect,
-	set_signal_status,
 	update_effect
 } from '../runtime.js';
 import * as e from '../errors.js';
@@ -40,6 +39,7 @@ import { flush_eager_effects, old_values, set_eager_effects, source, update } fr
 import { eager_effect, unlink_effect } from './effects.js';
 import { defer_effect } from './utils.js';
 import { UNINITIALIZED } from '../../../constants.js';
+import { set_signal_status } from './status.js';
 
 /** @type {Set<Batch>} */
 const batches = new Set();
diff --git a/packages/svelte/src/internal/client/reactivity/deriveds.js b/packages/svelte/src/internal/client/reactivity/deriveds.js
index 9dc324d3f9..b8a0982b05 100644
--- a/packages/svelte/src/internal/client/reactivity/deriveds.js
+++ b/packages/svelte/src/internal/client/reactivity/deriveds.js
@@ -17,7 +17,6 @@ import {
 import {
 	active_reaction,
 	active_effect,
-	set_signal_status,
 	update_reaction,
 	increment_write_version,
 	set_active_effect,
@@ -37,6 +36,7 @@ import { UNINITIALIZED } from '../../../constants.js';
 import { batch_values, current_batch } from './batch.js';
 import { unset_context } from './async.js';
 import { deferred } from '../../shared/utils.js';
+import { set_signal_status } from './status.js';
 
 /** @type {Effect | null} */
 export let current_async_effect = null;
diff --git a/packages/svelte/src/internal/client/reactivity/effects.js b/packages/svelte/src/internal/client/reactivity/effects.js
index 717fc35006..80ce63e0cf 100644
--- a/packages/svelte/src/internal/client/reactivity/effects.js
+++ b/packages/svelte/src/internal/client/reactivity/effects.js
@@ -9,7 +9,6 @@ import {
 	remove_reactions,
 	set_active_reaction,
 	set_is_destroying_effect,
-	set_signal_status,
 	untrack,
 	untracking
 } from '../runtime.js';
@@ -44,6 +43,7 @@ import { component_context, dev_current_component_function, dev_stack } from '..
 import { Batch, current_batch, schedule_effect } from './batch.js';
 import { flatten } from './async.js';
 import { without_reactive_context } from '../dom/elements/bindings/shared.js';
+import { set_signal_status } from './status.js';
 
 /**
  * @param {'$effect' | '$effect.pre' | '$inspect'} rune
diff --git a/packages/svelte/src/internal/client/reactivity/sources.js b/packages/svelte/src/internal/client/reactivity/sources.js
index 3f8d6cb09f..fcdd389fe4 100644
--- a/packages/svelte/src/internal/client/reactivity/sources.js
+++ b/packages/svelte/src/internal/client/reactivity/sources.js
@@ -6,7 +6,6 @@ import {
 	untracked_writes,
 	get,
 	set_untracked_writes,
-	set_signal_status,
 	untrack,
 	increment_write_version,
 	update_effect,
@@ -40,6 +39,7 @@ import { component_context, is_runes } from '../context.js';
 import { Batch, batch_values, eager_block_effects, schedule_effect } from './batch.js';
 import { proxy } from '../proxy.js';
 import { execute_derived } from './deriveds.js';
+import { set_signal_status } from './status.js';
 
 /** @type {Set<any>} */
 export let eager_effects = new Set();
diff --git a/packages/svelte/src/internal/client/reactivity/status.js b/packages/svelte/src/internal/client/reactivity/status.js
new file mode 100644
index 0000000000..d3aaa35968
--- /dev/null
+++ b/packages/svelte/src/internal/client/reactivity/status.js
@@ -0,0 +1,12 @@
+/** @import { Signal } from '#client' */
+import { CLEAN, DIRTY, MAYBE_DIRTY } from '#client/constants';
+
+const STATUS_MASK = ~(DIRTY | MAYBE_DIRTY | CLEAN);
+
+/**
+ * @param {Signal} signal
+ * @param {number} status
+ */
+export function set_signal_status(signal, status) {
+	signal.f = (signal.f & STATUS_MASK) | status;
+}
diff --git a/packages/svelte/src/internal/client/reactivity/utils.js b/packages/svelte/src/internal/client/reactivity/utils.js
index 0dd6b3212d..0d27cb8b84 100644
--- a/packages/svelte/src/internal/client/reactivity/utils.js
+++ b/packages/svelte/src/internal/client/reactivity/utils.js
@@ -1,6 +1,6 @@
 /** @import { Derived, Effect, Value } from '#client' */
 import { CLEAN, DERIVED, DIRTY, MAYBE_DIRTY, WAS_MARKED } from '#client/constants';
-import { set_signal_status } from '../runtime.js';
+import { set_signal_status } from './status.js';
 
 /**
  * @param {Value[] | null} deps
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 64c8409b8f..1b901268fc 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -56,6 +56,7 @@ import { handle_error } from './error-handling.js';
 import { UNINITIALIZED } from '../../constants.js';
 import { captured_signals } from './legacy.js';
 import { without_reactive_context } from './dom/elements/bindings/shared.js';
+import { set_signal_status } from './reactivity/status.js';
 
 export let is_updating_effect = false;
 
@@ -718,17 +719,6 @@ export function untrack(fn) {
 	}
 }
 
-const STATUS_MASK = ~(DIRTY | MAYBE_DIRTY | CLEAN);
-
-/**
- * @param {Signal} signal
- * @param {number} status
- * @returns {void}
- */
-export function set_signal_status(signal, status) {
-	signal.f = (signal.f & STATUS_MASK) | status;
-}
-
 /**
  * @param {Record<string | symbol, unknown>} obj
  * @param {Array<string | symbol>} keys
diff --git a/packages/svelte/src/legacy/legacy-client.js b/packages/svelte/src/legacy/legacy-client.js
index d4a053d1aa..ec90d2312c 100644
--- a/packages/svelte/src/legacy/legacy-client.js
+++ b/packages/svelte/src/legacy/legacy-client.js
@@ -3,7 +3,7 @@ import { DIRTY, LEGACY_PROPS, MAYBE_DIRTY } from '../internal/client/constants.j
 import { user_pre_effect } from '../internal/client/reactivity/effects.js';
 import { mutable_source, set } from '../internal/client/reactivity/sources.js';
 import { hydrate, mount, unmount } from '../internal/client/render.js';
-import { active_effect, get, set_signal_status } from '../internal/client/runtime.js';
+import { active_effect, get } from '../internal/client/runtime.js';
 import { flushSync } from '../internal/client/reactivity/batch.js';
 import { define_property, is_array } from '../internal/shared/utils.js';
 import * as e from '../internal/client/errors.js';
@@ -12,6 +12,7 @@ import { DEV } from 'esm-env';
 import { FILENAME } from '../constants.js';
 import { component_context, dev_current_component_function } from '../internal/client/context.js';
 import { async_mode_flag } from '../internal/flags/index.js';
+import { set_signal_status } from '../internal/client/reactivity/status.js';
 
 /**
  * Takes the same options as a Svelte 4 component and the component function and returns a Svelte 4 compatible component.

From f04f22ea4990c4d8336a205571cdbc05ecf819bb Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 9 Jan 2026 12:47:12 -0500
Subject: [PATCH 024/142] chore: use update_derived_status instead of
 set_signal_status where appropriate (#17442)

Co-authored-by: David Roizenman <hmnd@users.noreply.github.com>
---
 .../src/internal/client/reactivity/deriveds.js |  5 ++---
 .../src/internal/client/reactivity/sources.js  |  8 +++++---
 .../src/internal/client/reactivity/status.js   | 17 +++++++++++++++--
 packages/svelte/src/internal/client/runtime.js | 18 +++++++++++-------
 4 files changed, 33 insertions(+), 15 deletions(-)

diff --git a/packages/svelte/src/internal/client/reactivity/deriveds.js b/packages/svelte/src/internal/client/reactivity/deriveds.js
index b8a0982b05..48002d759f 100644
--- a/packages/svelte/src/internal/client/reactivity/deriveds.js
+++ b/packages/svelte/src/internal/client/reactivity/deriveds.js
@@ -36,7 +36,7 @@ import { UNINITIALIZED } from '../../../constants.js';
 import { batch_values, current_batch } from './batch.js';
 import { unset_context } from './async.js';
 import { deferred } from '../../shared/utils.js';
-import { set_signal_status } from './status.js';
+import { update_derived_status } from './status.js';
 
 /** @type {Effect | null} */
 export let current_async_effect = null;
@@ -385,7 +385,6 @@ export function update_derived(derived) {
 			batch_values.set(derived, value);
 		}
 	} else {
-		var status = (derived.f & CONNECTED) === 0 ? MAYBE_DIRTY : CLEAN;
-		set_signal_status(derived, status);
+		update_derived_status(derived);
 	}
 }
diff --git a/packages/svelte/src/internal/client/reactivity/sources.js b/packages/svelte/src/internal/client/reactivity/sources.js
index fcdd389fe4..6333962f41 100644
--- a/packages/svelte/src/internal/client/reactivity/sources.js
+++ b/packages/svelte/src/internal/client/reactivity/sources.js
@@ -39,7 +39,7 @@ import { component_context, is_runes } from '../context.js';
 import { Batch, batch_values, eager_block_effects, schedule_effect } from './batch.js';
 import { proxy } from '../proxy.js';
 import { execute_derived } from './deriveds.js';
-import { set_signal_status } from './status.js';
+import { set_signal_status, update_derived_status } from './status.js';
 
 /** @type {Set<any>} */
 export let eager_effects = new Set();
@@ -218,12 +218,14 @@ export function internal_set(source, value) {
 		}
 
 		if ((source.f & DERIVED) !== 0) {
+			const derived = /** @type {Derived} */ (source);
+
 			// if we are assigning to a dirty derived we set it to clean/maybe dirty but we also eagerly execute it to track the dependencies
 			if ((source.f & DIRTY) !== 0) {
-				execute_derived(/** @type {Derived} */ (source));
+				execute_derived(derived);
 			}
 
-			set_signal_status(source, (source.f & CONNECTED) !== 0 ? CLEAN : MAYBE_DIRTY);
+			update_derived_status(derived);
 		}
 
 		source.wv = increment_write_version();
diff --git a/packages/svelte/src/internal/client/reactivity/status.js b/packages/svelte/src/internal/client/reactivity/status.js
index d3aaa35968..024285e73a 100644
--- a/packages/svelte/src/internal/client/reactivity/status.js
+++ b/packages/svelte/src/internal/client/reactivity/status.js
@@ -1,5 +1,5 @@
-/** @import { Signal } from '#client' */
-import { CLEAN, DIRTY, MAYBE_DIRTY } from '#client/constants';
+/** @import { Derived, Signal } from '#client' */
+import { CLEAN, CONNECTED, DIRTY, MAYBE_DIRTY } from '#client/constants';
 
 const STATUS_MASK = ~(DIRTY | MAYBE_DIRTY | CLEAN);
 
@@ -10,3 +10,16 @@ const STATUS_MASK = ~(DIRTY | MAYBE_DIRTY | CLEAN);
 export function set_signal_status(signal, status) {
 	signal.f = (signal.f & STATUS_MASK) | status;
 }
+
+/**
+ * Set a derived's status to CLEAN or MAYBE_DIRTY based on its connection state.
+ * @param {Derived} derived
+ */
+export function update_derived_status(derived) {
+	// Only mark as MAYBE_DIRTY if disconnected and has dependencies.
+	if ((derived.f & CONNECTED) !== 0 || derived.deps === null) {
+		set_signal_status(derived, CLEAN);
+	} else {
+		set_signal_status(derived, MAYBE_DIRTY);
+	}
+}
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 1b901268fc..e1a442830b 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -56,7 +56,7 @@ import { handle_error } from './error-handling.js';
 import { UNINITIALIZED } from '../../constants.js';
 import { captured_signals } from './legacy.js';
 import { without_reactive_context } from './dom/elements/bindings/shared.js';
-import { set_signal_status } from './reactivity/status.js';
+import { set_signal_status, update_derived_status } from './reactivity/status.js';
 
 export let is_updating_effect = false;
 
@@ -375,16 +375,20 @@ function remove_reaction(signal, dependency) {
 		// allows us to skip the expensive work of disconnecting and immediately reconnecting it
 		(new_deps === null || !new_deps.includes(dependency))
 	) {
-		set_signal_status(dependency, MAYBE_DIRTY);
+		const derived = /** @type {Derived} */ (dependency);
+
 		// If we are working with a derived that is owned by an effect, then mark it as being
 		// disconnected and remove the mark flag, as it cannot be reliably removed otherwise
-		if ((dependency.f & CONNECTED) !== 0) {
-			dependency.f ^= CONNECTED;
-			dependency.f &= ~WAS_MARKED;
+		if ((derived.f & CONNECTED) !== 0) {
+			derived.f ^= CONNECTED;
+			derived.f &= ~WAS_MARKED;
 		}
+
+		update_derived_status(derived);
+
 		// Disconnect any reactions owned by this reaction
-		destroy_derived_effects(/** @type {Derived} **/ (dependency));
-		remove_reactions(/** @type {Derived} **/ (dependency), 0);
+		destroy_derived_effects(derived);
+		remove_reactions(derived, 0);
 	}
 }
 

From 359be81c094b35d12a2ce320127bfaa0ef431b6a Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 9 Jan 2026 12:52:21 -0500
Subject: [PATCH 025/142] chore: tidy up (#17443)

* tidy up

* unused
---
 packages/svelte/src/internal/client/reactivity/deriveds.js | 3 ---
 packages/svelte/src/internal/client/runtime.js             | 4 +---
 2 files changed, 1 insertion(+), 6 deletions(-)

diff --git a/packages/svelte/src/internal/client/reactivity/deriveds.js b/packages/svelte/src/internal/client/reactivity/deriveds.js
index 48002d759f..0fe83d7108 100644
--- a/packages/svelte/src/internal/client/reactivity/deriveds.js
+++ b/packages/svelte/src/internal/client/reactivity/deriveds.js
@@ -3,15 +3,12 @@
 import { DEV } from 'esm-env';
 import {
 	ERROR_VALUE,
-	CLEAN,
 	DERIVED,
 	DIRTY,
 	EFFECT_PRESERVED,
-	MAYBE_DIRTY,
 	STALE_REACTION,
 	ASYNC,
 	WAS_MARKED,
-	CONNECTED,
 	DESTROYED
 } from '#client/constants';
 import {
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index e1a442830b..5f215b0d31 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -1,4 +1,4 @@
-/** @import { Derived, Effect, Reaction, Signal, Source, Value } from '#client' */
+/** @import { Derived, Effect, Reaction, Source, Value } from '#client' */
 import { DEV } from 'esm-env';
 import { get_descriptors, get_prototype_of, index_of } from '../shared/utils.js';
 import {
@@ -28,7 +28,6 @@ import { old_values } from './reactivity/sources.js';
 import {
 	destroy_derived_effects,
 	execute_derived,
-	current_async_effect,
 	recent_async_deriveds,
 	update_derived
 } from './reactivity/deriveds.js';
@@ -44,7 +43,6 @@ import {
 	set_dev_current_component_function,
 	set_dev_stack
 } from './context.js';
-import * as w from './warnings.js';
 import {
 	Batch,
 	batch_values,

From f8bdadc1bf5e1122494b0269f04634f46e8225bf Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 9 Jan 2026 13:23:47 -0500
Subject: [PATCH 026/142] chore: simplify is_dirty (#17444)

* chore: simplify is_dirty

* tidy up
---
 .../src/internal/client/reactivity/effects.js |  2 +-
 .../svelte/src/internal/client/runtime.js     | 21 ++++++++-----------
 2 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/packages/svelte/src/internal/client/reactivity/effects.js b/packages/svelte/src/internal/client/reactivity/effects.js
index 80ce63e0cf..4cba446afc 100644
--- a/packages/svelte/src/internal/client/reactivity/effects.js
+++ b/packages/svelte/src/internal/client/reactivity/effects.js
@@ -328,7 +328,7 @@ export function legacy_pre_effect_reset() {
 
 			// If the effect is CLEAN, then make it MAYBE_DIRTY. This ensures we traverse through
 			// the effects dependencies and correctly ensure each dependency is up-to-date.
-			if ((effect.f & CLEAN) !== 0) {
+			if ((effect.f & CLEAN) !== 0 && effect.deps !== null) {
 				set_signal_status(effect, MAYBE_DIRTY);
 			}
 
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 5f215b0d31..ffd61ed776 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -166,21 +166,18 @@ export function is_dirty(reaction) {
 	}
 
 	if ((flags & MAYBE_DIRTY) !== 0) {
-		var dependencies = reaction.deps;
+		var dependencies = /** @type {Value[]} */ (reaction.deps);
+		var length = dependencies.length;
 
-		if (dependencies !== null) {
-			var length = dependencies.length;
+		for (var i = 0; i < length; i++) {
+			var dependency = dependencies[i];
 
-			for (var i = 0; i < length; i++) {
-				var dependency = dependencies[i];
-
-				if (is_dirty(/** @type {Derived} */ (dependency))) {
-					update_derived(/** @type {Derived} */ (dependency));
-				}
+			if (is_dirty(/** @type {Derived} */ (dependency))) {
+				update_derived(/** @type {Derived} */ (dependency));
+			}
 
-				if (dependency.wv > reaction.wv) {
-					return true;
-				}
+			if (dependency.wv > reaction.wv) {
+				return true;
 			}
 		}
 

From 5588832d1792130eade828410dc3777f9a713bc8 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 9 Jan 2026 15:57:22 -0500
Subject: [PATCH 027/142] fix: prevent derives without dependencies from ever
 re-running (#17445)

* fix: prevent derives without dependencies from ever re-running

* tweak
---
 .changeset/plenty-candies-notice.md           |  5 ++++
 .../internal/client/reactivity/deriveds.js    | 17 ++++++++++----
 .../fork-derived-class-instance/_config.js    | 22 ++++++++++++++++++
 .../fork-derived-class-instance/main.svelte   | 23 +++++++++++++++++++
 4 files changed, 62 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/plenty-candies-notice.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/fork-derived-class-instance/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/fork-derived-class-instance/main.svelte

diff --git a/.changeset/plenty-candies-notice.md b/.changeset/plenty-candies-notice.md
new file mode 100644
index 0000000000..41c5fce12a
--- /dev/null
+++ b/.changeset/plenty-candies-notice.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: prevent derives without dependencies from ever re-running
diff --git a/packages/svelte/src/internal/client/reactivity/deriveds.js b/packages/svelte/src/internal/client/reactivity/deriveds.js
index 0fe83d7108..59fb0f15aa 100644
--- a/packages/svelte/src/internal/client/reactivity/deriveds.js
+++ b/packages/svelte/src/internal/client/reactivity/deriveds.js
@@ -9,7 +9,8 @@ import {
 	STALE_REACTION,
 	ASYNC,
 	WAS_MARKED,
-	DESTROYED
+	DESTROYED,
+	CLEAN
 } from '#client/constants';
 import {
 	active_reaction,
@@ -33,7 +34,7 @@ import { UNINITIALIZED } from '../../../constants.js';
 import { batch_values, current_batch } from './batch.js';
 import { unset_context } from './async.js';
 import { deferred } from '../../shared/utils.js';
-import { update_derived_status } from './status.js';
+import { set_signal_status, update_derived_status } from './status.js';
 
 /** @type {Effect | null} */
 export let current_async_effect = null;
@@ -356,15 +357,21 @@ export function update_derived(derived) {
 	var value = execute_derived(derived);
 
 	if (!derived.equals(value)) {
+		derived.wv = increment_write_version();
+
 		// in a fork, we don't update the underlying value, just `batch_values`.
 		// the underlying value will be updated when the fork is committed.
 		// otherwise, the next time we get here after a 'real world' state
 		// change, `derived.equals` may incorrectly return `true`
-		if (!current_batch?.is_fork) {
+		if (!current_batch?.is_fork || derived.deps === null) {
 			derived.v = value;
-		}
 
-		derived.wv = increment_write_version();
+			// deriveds without dependencies should never be recomputed
+			if (derived.deps === null) {
+				set_signal_status(derived, CLEAN);
+				return;
+			}
+		}
 	}
 
 	// don't mark derived clean if we're reading it inside a
diff --git a/packages/svelte/tests/runtime-runes/samples/fork-derived-class-instance/_config.js b/packages/svelte/tests/runtime-runes/samples/fork-derived-class-instance/_config.js
new file mode 100644
index 0000000000..feac447536
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/fork-derived-class-instance/_config.js
@@ -0,0 +1,22 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	skip_no_async: true,
+	async test({ assert, target }) {
+		const [fork] = target.querySelectorAll('button');
+
+		fork.click();
+		await tick();
+
+		const [, increment] = target.querySelectorAll('button');
+		const p = target.querySelector('p');
+
+		assert.equal(p?.textContent, '0');
+
+		increment.click();
+		await tick();
+
+		assert.equal(p?.textContent, '1');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/fork-derived-class-instance/main.svelte b/packages/svelte/tests/runtime-runes/samples/fork-derived-class-instance/main.svelte
new file mode 100644
index 0000000000..3623c1df66
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/fork-derived-class-instance/main.svelte
@@ -0,0 +1,23 @@
+<script>
+	import { fork } from 'svelte';
+
+	class Counter {
+		count = $state(0);
+	}
+
+	let condition = $state(false);
+	let counter = $derived(new Counter());
+</script>
+
+<button onclick={() => {
+	fork(() => {
+		condition = true;
+	}).commit();
+}}>fork</button>
+
+{#if condition}
+	<button onclick={() => {
+		counter.count++;
+	}}>click</button>
+	<p>{counter.count}</p>
+{/if}

From 286b40c4526ce9970cb81ddd5e65b93b722fe468 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 9 Jan 2026 15:57:22 -0500
Subject: [PATCH 028/142] fix: prevent derives without dependencies from ever
 re-running (#17445)

* fix: prevent derives without dependencies from ever re-running

* tweak

Co-authored-by: David Roizenman <hmnd@users.noreply.github.com>
---
 .changeset/plenty-candies-notice.md           |  5 ++++
 .../internal/client/reactivity/deriveds.js    | 17 ++++++++++----
 .../fork-derived-class-instance/_config.js    | 22 ++++++++++++++++++
 .../fork-derived-class-instance/main.svelte   | 23 +++++++++++++++++++
 4 files changed, 62 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/plenty-candies-notice.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/fork-derived-class-instance/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/fork-derived-class-instance/main.svelte

diff --git a/.changeset/plenty-candies-notice.md b/.changeset/plenty-candies-notice.md
new file mode 100644
index 0000000000..41c5fce12a
--- /dev/null
+++ b/.changeset/plenty-candies-notice.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: prevent derives without dependencies from ever re-running
diff --git a/packages/svelte/src/internal/client/reactivity/deriveds.js b/packages/svelte/src/internal/client/reactivity/deriveds.js
index 0fe83d7108..59fb0f15aa 100644
--- a/packages/svelte/src/internal/client/reactivity/deriveds.js
+++ b/packages/svelte/src/internal/client/reactivity/deriveds.js
@@ -9,7 +9,8 @@ import {
 	STALE_REACTION,
 	ASYNC,
 	WAS_MARKED,
-	DESTROYED
+	DESTROYED,
+	CLEAN
 } from '#client/constants';
 import {
 	active_reaction,
@@ -33,7 +34,7 @@ import { UNINITIALIZED } from '../../../constants.js';
 import { batch_values, current_batch } from './batch.js';
 import { unset_context } from './async.js';
 import { deferred } from '../../shared/utils.js';
-import { update_derived_status } from './status.js';
+import { set_signal_status, update_derived_status } from './status.js';
 
 /** @type {Effect | null} */
 export let current_async_effect = null;
@@ -356,15 +357,21 @@ export function update_derived(derived) {
 	var value = execute_derived(derived);
 
 	if (!derived.equals(value)) {
+		derived.wv = increment_write_version();
+
 		// in a fork, we don't update the underlying value, just `batch_values`.
 		// the underlying value will be updated when the fork is committed.
 		// otherwise, the next time we get here after a 'real world' state
 		// change, `derived.equals` may incorrectly return `true`
-		if (!current_batch?.is_fork) {
+		if (!current_batch?.is_fork || derived.deps === null) {
 			derived.v = value;
-		}
 
-		derived.wv = increment_write_version();
+			// deriveds without dependencies should never be recomputed
+			if (derived.deps === null) {
+				set_signal_status(derived, CLEAN);
+				return;
+			}
+		}
 	}
 
 	// don't mark derived clean if we're reading it inside a
diff --git a/packages/svelte/tests/runtime-runes/samples/fork-derived-class-instance/_config.js b/packages/svelte/tests/runtime-runes/samples/fork-derived-class-instance/_config.js
new file mode 100644
index 0000000000..feac447536
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/fork-derived-class-instance/_config.js
@@ -0,0 +1,22 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	skip_no_async: true,
+	async test({ assert, target }) {
+		const [fork] = target.querySelectorAll('button');
+
+		fork.click();
+		await tick();
+
+		const [, increment] = target.querySelectorAll('button');
+		const p = target.querySelector('p');
+
+		assert.equal(p?.textContent, '0');
+
+		increment.click();
+		await tick();
+
+		assert.equal(p?.textContent, '1');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/fork-derived-class-instance/main.svelte b/packages/svelte/tests/runtime-runes/samples/fork-derived-class-instance/main.svelte
new file mode 100644
index 0000000000..3623c1df66
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/fork-derived-class-instance/main.svelte
@@ -0,0 +1,23 @@
+<script>
+	import { fork } from 'svelte';
+
+	class Counter {
+		count = $state(0);
+	}
+
+	let condition = $state(false);
+	let counter = $derived(new Counter());
+</script>
+
+<button onclick={() => {
+	fork(() => {
+		condition = true;
+	}).commit();
+}}>fork</button>
+
+{#if condition}
+	<button onclick={() => {
+		counter.count++;
+	}}>click</button>
+	<p>{counter.count}</p>
+{/if}

From 2c2339028657fa52f38bd904bef88927288438c5 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 9 Jan 2026 18:26:58 -0500
Subject: [PATCH 029/142] chore: const -> var

---
 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 ffd61ed776..52b24030fa 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -370,7 +370,7 @@ function remove_reaction(signal, dependency) {
 		// allows us to skip the expensive work of disconnecting and immediately reconnecting it
 		(new_deps === null || !new_deps.includes(dependency))
 	) {
-		const derived = /** @type {Derived} */ (dependency);
+		var derived = /** @type {Derived} */ (dependency);
 
 		// If we are working with a derived that is owned by an effect, then mark it as being
 		// disconnected and remove the mark flag, as it cannot be reliably removed otherwise

From ae224bea4937d1349366cb170a62cd438a1eb580 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Mon, 12 Jan 2026 14:59:07 -0500
Subject: [PATCH 030/142] fix: always reconnect deriveds in get, when
 appropriate (#17451)

* failing test

* fix: always reconnect deriveds in get, when appropriate

* shuffle code around a bit

* note to self
---
 .changeset/major-towns-grab.md                |  5 ++++
 .../svelte/src/internal/client/runtime.js     | 25 +++++++++---------
 .../samples/async-fork-snippet-dev/_config.js | 24 +++++++++++++++++
 .../async-fork-snippet-dev/main.svelte        | 26 +++++++++++++++++++
 4 files changed, 67 insertions(+), 13 deletions(-)
 create mode 100644 .changeset/major-towns-grab.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-fork-snippet-dev/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-fork-snippet-dev/main.svelte

diff --git a/.changeset/major-towns-grab.md b/.changeset/major-towns-grab.md
new file mode 100644
index 0000000000..de66b70313
--- /dev/null
+++ b/.changeset/major-towns-grab.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: always reconnect deriveds in get, when appropriate
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 52b24030fa..82c5f5a06f 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -596,14 +596,14 @@ export function get(signal) {
 		}
 	}
 
-	if (is_destroying_effect) {
-		if (old_values.has(signal)) {
-			return old_values.get(signal);
-		}
+	if (is_destroying_effect && old_values.has(signal)) {
+		return old_values.get(signal);
+	}
 
-		if (is_derived) {
-			var derived = /** @type {Derived} */ (signal);
+	if (is_derived) {
+		var derived = /** @type {Derived} */ (signal);
 
+		if (is_destroying_effect) {
 			var value = derived.v;
 
 			// if the derived is dirty and has reactions, or depends on the values that just changed, re-execute
@@ -619,14 +619,13 @@ export function get(signal) {
 
 			return value;
 		}
-	} else if (
-		is_derived &&
-		(!batch_values?.has(signal) || (current_batch?.is_fork && !effect_tracking()))
-	) {
-		derived = /** @type {Derived} */ (signal);
 
-		if (is_dirty(derived)) {
-			update_derived(derived);
+		// TODO this should probably just be `!batch_values?.has(derived)` — the second bit
+		// should be taken care of by clearing `batch_values` in `mark_reactions`?
+		if (!batch_values?.has(derived) || (current_batch?.is_fork && !effect_tracking())) {
+			if (is_dirty(derived)) {
+				update_derived(derived);
+			}
 		}
 
 		if (is_updating_effect && effect_tracking() && (derived.f & CONNECTED) === 0) {
diff --git a/packages/svelte/tests/runtime-runes/samples/async-fork-snippet-dev/_config.js b/packages/svelte/tests/runtime-runes/samples/async-fork-snippet-dev/_config.js
new file mode 100644
index 0000000000..2fb00562f5
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-fork-snippet-dev/_config.js
@@ -0,0 +1,24 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	compileOptions: {
+		dev: true
+	},
+
+	async test({ assert, target }) {
+		const [fork] = target.querySelectorAll('button');
+
+		fork.click();
+		await tick();
+
+		assert.htmlEqual(target.innerHTML, '<button>fork</button><button>false</button>');
+
+		const [, toggle] = target.querySelectorAll('button');
+
+		toggle.click();
+		await tick();
+
+		assert.htmlEqual(target.innerHTML, '<button>fork</button><button>true</button>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-fork-snippet-dev/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-fork-snippet-dev/main.svelte
new file mode 100644
index 0000000000..6945fcd153
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-fork-snippet-dev/main.svelte
@@ -0,0 +1,26 @@
+<script>
+	import { fork } from 'svelte';
+
+	let condition = $state(false);
+	let checked = $state(false);
+
+	const d = $derived({ checked });
+</script>
+
+<button onclick={() => {
+	fork(() => {
+		condition = true;
+	}).commit();
+}}>fork</button>
+
+{#if condition}
+	<!-- in dev, snippet arguments are read eagerly, outside a tracking context -->
+	<!-- this test checks that doing so doesn't prevent the derived from connecting -->
+	{#snippet foo({ checked })}
+		{checked}
+	{/snippet}
+
+	<button onclick={() => (checked = !checked)}>
+		{@render foo(d)}
+	</button>
+{/if}

From 7dbb5b478893056e4a9c43bdee5e34e64d86e588 Mon Sep 17 00:00:00 2001
From: David <david@hmnd.io>
Date: Mon, 12 Jan 2026 12:14:08 -0800
Subject: [PATCH 031/142] fix: derived reactivity and perf regressions (#17362)

* add test sample

* add test for sveltejs/kit#15059

* fix: reconnect deriveds inside branch effects

* add changeset

* fix: derived with no deps always set as MAYBE_DIRTY

fixes #17342

* add test for #17342

* additional changeset

* refactor: extract setting derived status to helper, apply to sources.js

* add test case for #17352

* fix: reconnect child deriveds when evaluating connected parent derived

fixes #17352

* fix import order causing Cannot read properties of undefined on dev load

* remove duplicate iteration over deps

* minor style tweaks

* oops, fix merge

* use update_derived_status, so that we never set a dep-less derived MAYBE_DIRTY

* tweak

* reaction.deps cannot be null for a MAYBE_DIRTY derived

* make it such that reactions without deps are never MAYBE_DIRTY

* since we no longer need to check reaction.deps === null, we can revert this bit

* more explicit check

* tidy up

* more

* gah whoops

* move import

* simplify test

* make dep-less derived behaviour more explicit, move it above is_destroying_effect handling

* remove test - this is adequately covered by #17445

* replace tricky unit test with component-based test

* remove incorrect test

* remove the BRANCH_EFFECT stuff

* tidy up

* DRY

* tweak, add explanatory comment

* tweak

* explanatory comment

* remove changeset

* update changeset

---------

Co-authored-by: Tee Ming <chewteeming01@gmail.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/beige-sloths-cry.md                |  5 ++
 .../svelte/src/internal/client/runtime.js     | 26 +++++++---
 .../derived-read-outside-reaction/_config.js  | 47 +++++++++++++++++++
 .../derived-read-outside-reaction/main.svelte | 30 ++++++++++++
 4 files changed, 101 insertions(+), 7 deletions(-)
 create mode 100644 .changeset/beige-sloths-cry.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/derived-read-outside-reaction/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/derived-read-outside-reaction/main.svelte

diff --git a/.changeset/beige-sloths-cry.md b/.changeset/beige-sloths-cry.md
new file mode 100644
index 0000000000..013fd2f6cc
--- /dev/null
+++ b/.changeset/beige-sloths-cry.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: reconnect clean deriveds when they are read in a reactive context
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 82c5f5a06f..0e12324d72 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -620,15 +620,27 @@ export function get(signal) {
 			return value;
 		}
 
-		// TODO this should probably just be `!batch_values?.has(derived)` — the second bit
-		// should be taken care of by clearing `batch_values` in `mark_reactions`?
-		if (!batch_values?.has(derived) || (current_batch?.is_fork && !effect_tracking())) {
-			if (is_dirty(derived)) {
-				update_derived(derived);
+		// connect disconnected deriveds if we are reading them inside an effect,
+		// or inside another derived that is already connected
+		var should_connect =
+			(derived.f & CONNECTED) === 0 &&
+			!untracking &&
+			active_reaction !== null &&
+			(is_updating_effect || (active_reaction.f & CONNECTED) !== 0);
+
+		var is_new = derived.deps === null;
+
+		if (is_dirty(derived)) {
+			if (should_connect) {
+				// set the flag before `update_derived`, so that the derived
+				// is added as a reaction to its dependencies
+				derived.f |= CONNECTED;
 			}
+
+			update_derived(derived);
 		}
 
-		if (is_updating_effect && effect_tracking() && (derived.f & CONNECTED) === 0) {
+		if (should_connect && !is_new) {
 			reconnect(derived);
 		}
 	}
@@ -652,7 +664,7 @@ export function get(signal) {
 function reconnect(derived) {
 	if (derived.deps === null) return;
 
-	derived.f ^= CONNECTED;
+	derived.f |= CONNECTED;
 
 	for (const dep of derived.deps) {
 		(dep.reactions ??= []).push(derived);
diff --git a/packages/svelte/tests/runtime-runes/samples/derived-read-outside-reaction/_config.js b/packages/svelte/tests/runtime-runes/samples/derived-read-outside-reaction/_config.js
new file mode 100644
index 0000000000..f3a71b93e6
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/derived-read-outside-reaction/_config.js
@@ -0,0 +1,47 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	html: `
+		<button>+1</button>
+		<button>add number</button>
+		<p>1, 2, 3</p>
+	`,
+
+	test({ assert, target }) {
+		const [button1, button2] = target.querySelectorAll('button');
+
+		button1.click();
+		flushSync();
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>+1</button>
+				<button>add number</button>
+				<p>2, 4, 6</p>
+			`
+		);
+
+		button2.click();
+		flushSync();
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>+1</button>
+				<button>add number</button>
+				<p>2, 4, 6, 8</p>
+			`
+		);
+
+		button1.click();
+		flushSync();
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>+1</button>
+				<button>add number</button>
+				<p>3, 6, 9, 12</p>
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/derived-read-outside-reaction/main.svelte b/packages/svelte/tests/runtime-runes/samples/derived-read-outside-reaction/main.svelte
new file mode 100644
index 0000000000..0b5096dfa4
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/derived-read-outside-reaction/main.svelte
@@ -0,0 +1,30 @@
+<script lang="ts">
+	class Item {
+		product: number;
+
+		constructor(n: number) {
+			this.product = $derived(multiplier * n);
+		}
+	}
+
+	let numbers = $state([1, 2, 3]);
+	let multiplier = $state(1);
+
+	let items = $derived(numbers.map((n) => new Item(n)))
+	let products = $derived(items.map(item => item.product));
+</script>
+
+<button onclick={() => {
+	multiplier += 1;
+}}>+1</button>
+
+<button onclick={() => {
+	numbers.push(numbers.length + 1);
+
+	// this is load-bearing — by reading it outside a reaction, we recompute
+	// `products`, removing it as a reaction from `Item.product` dependencies,
+	// but we don't add it as a reaction to the new `Item.product` dependencies
+	products;
+}}>add number</button>
+
+<p>{products.join(', ')}</p>

From 51c7f7152c244512067fa52312e15a596d1ae1c9 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Mon, 12 Jan 2026 15:15:00 -0500
Subject: [PATCH 032/142] Version Packages (#17410)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/better-games-invite.md   |  5 -----
 .changeset/empty-paths-smile.md     |  5 -----
 .changeset/major-towns-grab.md      |  5 -----
 .changeset/plenty-candies-notice.md |  5 -----
 .changeset/seven-llamas-care.md     |  5 -----
 .changeset/spicy-years-stick.md     |  5 -----
 .changeset/tall-clocks-turn.md      |  5 -----
 .changeset/tall-phones-fix.md       |  5 -----
 .changeset/thick-islands-pull.md    |  5 -----
 packages/svelte/CHANGELOG.md        | 22 ++++++++++++++++++++++
 packages/svelte/package.json        |  2 +-
 packages/svelte/src/version.js      |  2 +-
 12 files changed, 24 insertions(+), 47 deletions(-)
 delete mode 100644 .changeset/better-games-invite.md
 delete mode 100644 .changeset/empty-paths-smile.md
 delete mode 100644 .changeset/major-towns-grab.md
 delete mode 100644 .changeset/plenty-candies-notice.md
 delete mode 100644 .changeset/seven-llamas-care.md
 delete mode 100644 .changeset/spicy-years-stick.md
 delete mode 100644 .changeset/tall-clocks-turn.md
 delete mode 100644 .changeset/tall-phones-fix.md
 delete mode 100644 .changeset/thick-islands-pull.md

diff --git a/.changeset/better-games-invite.md b/.changeset/better-games-invite.md
deleted file mode 100644
index 8361a1e9bb..0000000000
--- a/.changeset/better-games-invite.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: don't transform references of function declarations in legacy mode
diff --git a/.changeset/empty-paths-smile.md b/.changeset/empty-paths-smile.md
deleted file mode 100644
index 687ad19b24..0000000000
--- a/.changeset/empty-paths-smile.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: notify deriveds of changes to sources inside forks
diff --git a/.changeset/major-towns-grab.md b/.changeset/major-towns-grab.md
deleted file mode 100644
index de66b70313..0000000000
--- a/.changeset/major-towns-grab.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: always reconnect deriveds in get, when appropriate
diff --git a/.changeset/plenty-candies-notice.md b/.changeset/plenty-candies-notice.md
deleted file mode 100644
index 41c5fce12a..0000000000
--- a/.changeset/plenty-candies-notice.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: prevent derives without dependencies from ever re-running
diff --git a/.changeset/seven-llamas-care.md b/.changeset/seven-llamas-care.md
deleted file mode 100644
index 1b41b4848a..0000000000
--- a/.changeset/seven-llamas-care.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: correctly update writable deriveds inside forks
diff --git a/.changeset/spicy-years-stick.md b/.changeset/spicy-years-stick.md
deleted file mode 100644
index 76834e8381..0000000000
--- a/.changeset/spicy-years-stick.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: remove `$inspect` calls after await expressions when compiling for production server code
diff --git a/.changeset/tall-clocks-turn.md b/.changeset/tall-clocks-turn.md
deleted file mode 100644
index 22cefcff30..0000000000
--- a/.changeset/tall-clocks-turn.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: clear batch between runs
diff --git a/.changeset/tall-phones-fix.md b/.changeset/tall-phones-fix.md
deleted file mode 100644
index 29e57c060f..0000000000
--- a/.changeset/tall-phones-fix.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: adjust `loc` property of `Program` nodes created from `<script>` elements
diff --git a/.changeset/thick-islands-pull.md b/.changeset/thick-islands-pull.md
deleted file mode 100644
index f987d72260..0000000000
--- a/.changeset/thick-islands-pull.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: don't revert source to UNINITIALIZED state when time travelling
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index dc0edbaf79..c8670d5d3c 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,27 @@
 # svelte
 
+## 5.46.2
+
+### Patch Changes
+
+- fix: don't transform references of function declarations in legacy mode ([#17431](https://github.com/sveltejs/svelte/pull/17431))
+
+- fix: notify deriveds of changes to sources inside forks ([#17437](https://github.com/sveltejs/svelte/pull/17437))
+
+- fix: always reconnect deriveds in get, when appropriate ([#17451](https://github.com/sveltejs/svelte/pull/17451))
+
+- fix: prevent derives without dependencies from ever re-running ([`286b40c4526ce9970cb81ddd5e65b93b722fe468`](https://github.com/sveltejs/svelte/commit/286b40c4526ce9970cb81ddd5e65b93b722fe468))
+
+- fix: correctly update writable deriveds inside forks ([#17437](https://github.com/sveltejs/svelte/pull/17437))
+
+- fix: remove `$inspect` calls after await expressions when compiling for production server code ([#17407](https://github.com/sveltejs/svelte/pull/17407))
+
+- fix: clear batch between runs ([#17424](https://github.com/sveltejs/svelte/pull/17424))
+
+- fix: adjust `loc` property of `Program` nodes created from `<script>` elements ([#17428](https://github.com/sveltejs/svelte/pull/17428))
+
+- fix: don't revert source to UNINITIALIZED state when time travelling ([#17409](https://github.com/sveltejs/svelte/pull/17409))
+
 ## 5.46.1
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 7affd91207..243dd9c23b 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": "5.46.1",
+  "version": "5.46.2",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index c28af94e19..de7c0e9fbb 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 = '5.46.1';
+export const VERSION = '5.46.2';
 export const PUBLIC_VERSION = '5';

From ed8dcd063625062f03291f2f086fee75e1dc5105 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Mon, 12 Jan 2026 16:57:22 -0500
Subject: [PATCH 033/142] Version Packages (#17458)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/beige-sloths-cry.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/beige-sloths-cry.md

diff --git a/.changeset/beige-sloths-cry.md b/.changeset/beige-sloths-cry.md
deleted file mode 100644
index 013fd2f6cc..0000000000
--- a/.changeset/beige-sloths-cry.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: reconnect clean deriveds when they are read in a reactive context
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index c8670d5d3c..f822258e36 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,11 @@
 # svelte
 
+## 5.46.3
+
+### Patch Changes
+
+- fix: reconnect clean deriveds when they are read in a reactive context ([#17362](https://github.com/sveltejs/svelte/pull/17362))
+
 ## 5.46.2
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 243dd9c23b..d7c25b28f1 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": "5.46.2",
+  "version": "5.46.3",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index de7c0e9fbb..9f84875407 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 = '5.46.2';
+export const VERSION = '5.46.3';
 export const PUBLIC_VERSION = '5';

From 6d90b96e990d9dd45f55effb4431393c3e610937 Mon Sep 17 00:00:00 2001
From: "Dominik G." <dominik.goepel@gmx.de>
Date: Tue, 13 Jan 2026 21:49:41 +0000
Subject: [PATCH 034/142] chore: edit changelog (#17463)

* chore: 5.46.2 was never published, merge the changes into 5.46.3 to avoid confusion

* chore: add notice about missing 5.46.2
---
 packages/svelte/CHANGELOG.md | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index f822258e36..bf22761869 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -6,10 +6,6 @@
 
 - fix: reconnect clean deriveds when they are read in a reactive context ([#17362](https://github.com/sveltejs/svelte/pull/17362))
 
-## 5.46.2
-
-### Patch Changes
-
 - fix: don't transform references of function declarations in legacy mode ([#17431](https://github.com/sveltejs/svelte/pull/17431))
 
 - fix: notify deriveds of changes to sources inside forks ([#17437](https://github.com/sveltejs/svelte/pull/17437))
@@ -28,6 +24,12 @@
 
 - fix: don't revert source to UNINITIALIZED state when time travelling ([#17409](https://github.com/sveltejs/svelte/pull/17409))
 
+## 5.46.2
+
+### Notice
+
+Not published due to CI issue
+
 ## 5.46.1
 
 ### Patch Changes

From ef81048e238844b729942441541d6dcfe6c8ccca Mon Sep 17 00:00:00 2001
From: Elliott Johnson <hello@ell.iott.dev>
Date: Thu, 15 Jan 2026 09:13:33 -0700
Subject: [PATCH 035/142] Merge commit from fork

* fix: Use `devalue.uneval` to serialize `hydratable` keys

* oops
---
 .changeset/tasty-vans-repeat.md                    |  5 +++++
 packages/svelte/src/internal/server/renderer.js    |  3 ++-
 .../samples/hydratable-script-escape/_config.js    | 14 ++++++++++++++
 .../samples/hydratable-script-escape/main.svelte   |  9 +++++++++
 4 files changed, 30 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/tasty-vans-repeat.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/hydratable-script-escape/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/hydratable-script-escape/main.svelte

diff --git a/.changeset/tasty-vans-repeat.md b/.changeset/tasty-vans-repeat.md
new file mode 100644
index 0000000000..d95e8de7e7
--- /dev/null
+++ b/.changeset/tasty-vans-repeat.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: use `devalue.uneval` to serialize `hydratable` keys
diff --git a/packages/svelte/src/internal/server/renderer.js b/packages/svelte/src/internal/server/renderer.js
index 1ecc90ba1f..82f8025759 100644
--- a/packages/svelte/src/internal/server/renderer.js
+++ b/packages/svelte/src/internal/server/renderer.js
@@ -10,6 +10,7 @@ import { BLOCK_CLOSE, BLOCK_OPEN } from './hydration.js';
 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';
 
 /** @typedef {'head' | 'body'} RendererType */
 /** @typedef {{ [key in RendererType]: string }} AccumulatedContent */
@@ -669,7 +670,7 @@ export class Renderer {
 				for (const p of v.promises) await p;
 			}
 
-			entries.push(`[${JSON.stringify(k)},${v.serialized}]`);
+			entries.push(`[${devalue.uneval(k)},${v.serialized}]`);
 		}
 
 		let prelude = `const h = (window.__svelte ??= {}).h ??= new Map();`;
diff --git a/packages/svelte/tests/runtime-runes/samples/hydratable-script-escape/_config.js b/packages/svelte/tests/runtime-runes/samples/hydratable-script-escape/_config.js
new file mode 100644
index 0000000000..bc51795565
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/hydratable-script-escape/_config.js
@@ -0,0 +1,14 @@
+import { test } from '../../test';
+
+export default test({
+	skip_no_async: true,
+	mode: ['hydrate'],
+
+	props: {
+		key: '</script><script>throw new Error("pwned")</script>'
+	},
+
+	async test() {
+		// this test will fail when evaluating the `head` script if the vulnerability is present
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/hydratable-script-escape/main.svelte b/packages/svelte/tests/runtime-runes/samples/hydratable-script-escape/main.svelte
new file mode 100644
index 0000000000..1327492190
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/hydratable-script-escape/main.svelte
@@ -0,0 +1,9 @@
+<script>
+	import { hydratable } from "svelte";
+
+	const { key } = $props();
+
+	const value = await hydratable(key, () => Promise.resolve('safe'));
+</script>
+
+<p>{value}</p>

From cfc7e0a8c3b1846f0c17388735eb0263b53b93a2 Mon Sep 17 00:00:00 2001
From: Elliott Johnson <sejohnson@torchcloudconsulting.com>
Date: Thu, 15 Jan 2026 09:15:26 -0700
Subject: [PATCH 036/142] chore: Upgrade devalue (#17475)

---
 packages/svelte/package.json |  2 +-
 pnpm-lock.yaml               | 10 +++++-----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index d7c25b28f1..8bd600545f 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -174,7 +174,7 @@
     "aria-query": "^5.3.1",
     "axobject-query": "^4.1.0",
     "clsx": "^2.1.1",
-    "devalue": "^5.5.0",
+    "devalue": "^5.6.2",
     "esm-env": "^1.2.1",
     "esrap": "^2.2.1",
     "is-reference": "^3.0.3",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 05298fe8e3..b616fc0577 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -90,8 +90,8 @@ importers:
         specifier: ^2.1.1
         version: 2.1.1
       devalue:
-        specifier: ^5.5.0
-        version: 5.5.0
+        specifier: ^5.6.2
+        version: 5.6.2
       esm-env:
         specifier: ^1.2.1
         version: 1.2.1
@@ -1219,8 +1219,8 @@ packages:
     engines: {node: '>=0.10'}
     hasBin: true
 
-  devalue@5.5.0:
-    resolution: {integrity: sha512-69sM5yrHfFLJt0AZ9QqZXGCPfJ7fQjvpln3Rq5+PS03LD32Ost1Q9N+eEnaQwGRIriKkMImXD56ocjQmfjbV3w==}
+  devalue@5.6.2:
+    resolution: {integrity: sha512-nPRkjWzzDQlsejL1WVifk5rvcFi/y1onBRxjaFMjZeR9mFpqu2gmAZ9xUB9/IEanEP/vBtGeGganC/GO1fmufg==}
 
   dir-glob@3.0.1:
     resolution: {integrity: sha512-WkrWp9GR4KXfKGYzOLmTuGVi1UWFfws377n9cc55/tb6DuqyF6pcQ5AbiHEshaDpY9v6oaSr2XCDidGmMwdzIA==}
@@ -3500,7 +3500,7 @@ snapshots:
   detect-libc@1.0.3:
     optional: true
 
-  devalue@5.5.0: {}
+  devalue@5.6.2: {}
 
   dir-glob@3.0.1:
     dependencies:

From 0718a26b435b927428dee57a71a91c1a77dc19cb Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Thu, 15 Jan 2026 09:22:53 -0700
Subject: [PATCH 037/142] Version Packages (#17476)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/tasty-vans-repeat.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/tasty-vans-repeat.md

diff --git a/.changeset/tasty-vans-repeat.md b/.changeset/tasty-vans-repeat.md
deleted file mode 100644
index d95e8de7e7..0000000000
--- a/.changeset/tasty-vans-repeat.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: use `devalue.uneval` to serialize `hydratable` keys
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index bf22761869..a767760641 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,11 @@
 # svelte
 
+## 5.46.4
+
+### Patch Changes
+
+- fix: use `devalue.uneval` to serialize `hydratable` keys ([`ef81048e238844b729942441541d6dcfe6c8ccca`](https://github.com/sveltejs/svelte/commit/ef81048e238844b729942441541d6dcfe6c8ccca))
+
 ## 5.46.3
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 8bd600545f..1723e3d00a 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": "5.46.3",
+  "version": "5.46.4",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 9f84875407..96c48a055c 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 = '5.46.3';
+export const VERSION = '5.46.4';
 export const PUBLIC_VERSION = '5';

From 17c22969d8f7b1723eae58075fbb32b530518e22 Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Fri, 16 Jan 2026 22:33:11 +0100
Subject: [PATCH 038/142] fix: don't reset static elements with debug/snippets
 (#17477)

---
 .changeset/little-aliens-pick.md                          | 5 +++++
 .../phases/3-transform/client/visitors/RegularElement.js  | 7 ++++---
 .../phases/3-transform/client/visitors/shared/fragment.js | 5 ++---
 .../tests/hydration/samples/no-reset-debug/_config.js     | 3 +++
 .../tests/hydration/samples/no-reset-debug/main.svelte    | 8 ++++++++
 .../tests/hydration/samples/no-reset-snippet/_config.js   | 3 +++
 .../tests/hydration/samples/no-reset-snippet/main.svelte  | 6 ++++++
 7 files changed, 31 insertions(+), 6 deletions(-)
 create mode 100644 .changeset/little-aliens-pick.md
 create mode 100644 packages/svelte/tests/hydration/samples/no-reset-debug/_config.js
 create mode 100644 packages/svelte/tests/hydration/samples/no-reset-debug/main.svelte
 create mode 100644 packages/svelte/tests/hydration/samples/no-reset-snippet/_config.js
 create mode 100644 packages/svelte/tests/hydration/samples/no-reset-snippet/main.svelte

diff --git a/.changeset/little-aliens-pick.md b/.changeset/little-aliens-pick.md
new file mode 100644
index 0000000000..1433625551
--- /dev/null
+++ b/.changeset/little-aliens-pick.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: don't reset static elements with debug/snippets
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 690715df84..c780350d3e 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
@@ -21,7 +21,7 @@ import {
 	build_set_class,
 	build_set_style
 } from './shared/element.js';
-import { process_children } from './shared/fragment.js';
+import { process_children, is_static_element } from './shared/fragment.js';
 import { build_render_statement, build_template_chunk, Memoizer } from './shared/utils.js';
 import { visit_event_attribute } from './shared/events.js';
 
@@ -356,8 +356,9 @@ export function RegularElement(node, context) {
 		let arg = context.state.node;
 
 		// If `hydrate_node` is set inside the element, we need to reset it
-		// after the element has been hydrated
-		let needs_reset = trimmed.some((node) => node.type !== 'Text');
+		// after the element has been hydrated. We need to check if any child
+		// would actually advance the hydrate_node cursor - static elements don't.
+		let needs_reset = trimmed.some((node) => node.type !== 'Text' && !is_static_element(node));
 
 		// The same applies if it's a `<template>` element, since we need to
 		// set the value of `hydrate_node` to `node.content`
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 ff931842d8..59b93f24ef 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
@@ -98,7 +98,7 @@ export function process_children(nodes, initial, is_element, context) {
 
 			let child_state = context.state;
 
-			if (is_static_element(node, context.state)) {
+			if (is_static_element(node)) {
 				skipped += 1;
 			} else if (
 				node.type === 'EachBlock' &&
@@ -137,9 +137,8 @@ export function process_children(nodes, initial, is_element, context) {
 
 /**
  * @param {AST.SvelteNode} node
- * @param {ComponentContext["state"]} state
  */
-function is_static_element(node, state) {
+export function is_static_element(node) {
 	if (node.type !== 'RegularElement') return false;
 	if (node.fragment.metadata.dynamic) return false;
 	if (is_custom_element_node(node)) return false; // we're setting all attributes on custom elements through properties
diff --git a/packages/svelte/tests/hydration/samples/no-reset-debug/_config.js b/packages/svelte/tests/hydration/samples/no-reset-debug/_config.js
new file mode 100644
index 0000000000..f47bee71df
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/no-reset-debug/_config.js
@@ -0,0 +1,3 @@
+import { test } from '../../test';
+
+export default test({});
diff --git a/packages/svelte/tests/hydration/samples/no-reset-debug/main.svelte b/packages/svelte/tests/hydration/samples/no-reset-debug/main.svelte
new file mode 100644
index 0000000000..915aa0152d
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/no-reset-debug/main.svelte
@@ -0,0 +1,8 @@
+<script>
+	let test = 42;
+</script>
+
+<div>
+	{@debug test}
+	<span>something</span>
+</div>
\ No newline at end of file
diff --git a/packages/svelte/tests/hydration/samples/no-reset-snippet/_config.js b/packages/svelte/tests/hydration/samples/no-reset-snippet/_config.js
new file mode 100644
index 0000000000..f47bee71df
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/no-reset-snippet/_config.js
@@ -0,0 +1,3 @@
+import { test } from '../../test';
+
+export default test({});
diff --git a/packages/svelte/tests/hydration/samples/no-reset-snippet/main.svelte b/packages/svelte/tests/hydration/samples/no-reset-snippet/main.svelte
new file mode 100644
index 0000000000..c6668c0684
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/no-reset-snippet/main.svelte
@@ -0,0 +1,6 @@
+<div>
+	{#snippet test()}
+		
+	{/snippet}
+	<span>something</span>
+</div>
\ No newline at end of file

From a903e9408b6d916fa45a57fb570ac6b74742717d Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Fri, 16 Jan 2026 22:35:05 +0100
Subject: [PATCH 039/142] fix: mark subtree of svelte boundary as dynamic
 (#17468)

---
 .changeset/curly-cats-make.md                                | 5 +++++
 .../src/compiler/phases/2-analyze/visitors/SvelteBoundary.js | 3 +++
 .../tests/runtime-runes/samples/static-boundary/_config.js   | 5 +++++
 .../tests/runtime-runes/samples/static-boundary/main.svelte  | 5 +++++
 4 files changed, 18 insertions(+)
 create mode 100644 .changeset/curly-cats-make.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/static-boundary/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/static-boundary/main.svelte

diff --git a/.changeset/curly-cats-make.md b/.changeset/curly-cats-make.md
new file mode 100644
index 0000000000..393f8ec7e8
--- /dev/null
+++ b/.changeset/curly-cats-make.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: mark subtree of svelte boundary as dynamic
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteBoundary.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteBoundary.js
index 35af96ba12..e0014aa7b2 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteBoundary.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteBoundary.js
@@ -1,6 +1,7 @@
 /** @import { AST } from '#compiler' */
 /** @import { Context } from '../types' */
 import * as e from '../../../errors.js';
+import { mark_subtree_dynamic } from './shared/fragment.js';
 
 const valid = ['onerror', 'failed', 'pending'];
 
@@ -23,5 +24,7 @@ export function SvelteBoundary(node, context) {
 		}
 	}
 
+	mark_subtree_dynamic(context.path);
+
 	context.next();
 }
diff --git a/packages/svelte/tests/runtime-runes/samples/static-boundary/_config.js b/packages/svelte/tests/runtime-runes/samples/static-boundary/_config.js
new file mode 100644
index 0000000000..d986ed8cd5
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/static-boundary/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	html: '<div><div>test</div></div>'
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/static-boundary/main.svelte b/packages/svelte/tests/runtime-runes/samples/static-boundary/main.svelte
new file mode 100644
index 0000000000..7f43a1afaf
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/static-boundary/main.svelte
@@ -0,0 +1,5 @@
+<div>
+	<svelte:boundary>
+		<div>test</div>
+	</svelte:boundary>
+</div>
\ No newline at end of file

From b934372a3cfb75437e2d3a7aac3c171b17887bcc Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Fri, 16 Jan 2026 21:36:02 +0000
Subject: [PATCH 040/142] chore: prevent two concurrent running release
 workflows (#17465)

---
 .github/workflows/release.yml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index b78346d883..80d2ad1f8e 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -5,6 +5,11 @@ on:
     branches:
       - main
 
+concurrency:
+  # prevent two release workflows from running at once
+  # race conditions here can result in releases failing
+  group: ${{ github.workflow }}
+
 permissions: {}
 jobs:
   release:

From 3046004ec3486d814b9f842024a7fa7dcc2444cb Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Sun, 18 Jan 2026 15:06:18 -0500
Subject: [PATCH 041/142] chore: use injected css in sandbox (#17485)

---
 playgrounds/sandbox/svelte.config.js | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/playgrounds/sandbox/svelte.config.js b/playgrounds/sandbox/svelte.config.js
index 68ac605385..33e8c98908 100644
--- a/playgrounds/sandbox/svelte.config.js
+++ b/playgrounds/sandbox/svelte.config.js
@@ -1,5 +1,8 @@
 export default {
+	/** @type {import('svelte/compiler').CompileOptions} */
 	compilerOptions: {
+		css: 'injected',
+
 		hmr: false,
 
 		experimental: {

From 645eb1225803a5042f7e1c622ac7fb0634e6bf2a Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Sun, 18 Jan 2026 22:53:11 +0100
Subject: [PATCH 042/142] feat: customizable select (#17429)

* feat: customizable select

* fix: treat inner of options as separate templates

* fix: add hydration comment

* fix: clear with textContent

* fix: mark rich content option as dynamic and allow optgroup

* fix: allow select with rich content and rename

* chore: revert tests

* fix: recursively check rich options

* chore: change name of template

* fix: mark boundary as dynamic

* chore: add snapshot tests

* chore: include comprehensive hydration test

* fix: consider `selectedelement` as ancestor of `option` elements

* fix: make `:has` work with `selectedcontent`

* chore: failing test for css

* fix: also return parent for adjacent_only

* fix: move hydration marker at the end

* chore: apply suggestions from code review

Co-authored-by: Rich Harris <rich.harris@vercel.com>

* fix: treat text elements in select and optgroup as rich

* fix hydration

* colocate code

* drop the element, it's cleaner

* rename module

* update test

* Update .changeset/chubby-dingos-laugh.md

* fix a11y warning that occurs when button only contains selectedcontent

* remove unused parameter

* last part is redundant

* simplify

* unnecessary, the constraints overlap

* this is taken care of during analysis

* simplify

* tweak

* tweak

* tweak

* fix/tweak

* tweak

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/chubby-dingos-laugh.md             |   5 +
 .../phases/2-analyze/css/css-prune.js         |  60 +++
 .../2-analyze/visitors/RegularElement.js      |  15 +-
 .../2-analyze/visitors/shared/a11y/index.js   |   4 +
 .../client/visitors/RegularElement.js         |  61 ++-
 .../server/visitors/RegularElement.js         |  40 +-
 packages/svelte/src/compiler/phases/nodes.js  |  95 ++++
 packages/svelte/src/html-tree-validation.js   |   6 +-
 .../dom/elements/customizable-select.js       |  51 +++
 packages/svelte/src/internal/client/index.js  |   1 +
 .../svelte/src/internal/server/renderer.js    |  10 +-
 .../css/samples/selectedcontent/expected.css  |  44 ++
 .../css/samples/selectedcontent/input.svelte  |  53 +++
 .../samples/optgroup-rich-content/_config.js  |  31 ++
 .../optgroup-rich-content/_expected.html      |   1 +
 .../samples/optgroup-rich-content/main.svelte |  16 +
 .../option-rich-content-continues/_config.js  |  34 ++
 .../_expected.html                            |   1 +
 .../option-rich-content-continues/main.svelte |  12 +
 .../option-rich-content-static/_config.js     |  39 ++
 .../option-rich-content-static/_expected.html |   1 +
 .../option-rich-content-static/main.svelte    |   5 +
 .../samples/rich-select/Option.svelte         |   1 +
 .../hydration/samples/rich-select/_config.js  |   3 +
 .../hydration/samples/rich-select/main.svelte | 173 ++++++++
 .../samples/optgroup-rich-content/_config.js  |  31 ++
 .../samples/optgroup-rich-content/main.svelte |  19 +
 .../samples/option-rich-content/_config.js    |  37 ++
 .../samples/option-rich-content/main.svelte   |  15 +
 .../rich-option-component/Content.svelte      |   5 +
 .../samples/rich-option-component/_config.js  |  26 ++
 .../samples/rich-option-component/main.svelte |  15 +
 .../select-with-rich-content/Option.svelte    |   1 +
 .../_expected/client/Option.svelte.js         |  11 +
 .../_expected/client/index.svelte.js          | 412 ++++++++++++++++++
 .../_expected/server/Option.svelte.js         |   7 +
 .../_expected/server/index.svelte.js          | 233 ++++++++++
 .../select-with-rich-content/index.svelte     | 157 +++++++
 .../a11y-consider-explicit-label/input.svelte |  11 +
 39 files changed, 1728 insertions(+), 14 deletions(-)
 create mode 100644 .changeset/chubby-dingos-laugh.md
 create mode 100644 packages/svelte/src/internal/client/dom/elements/customizable-select.js
 create mode 100644 packages/svelte/tests/css/samples/selectedcontent/expected.css
 create mode 100644 packages/svelte/tests/css/samples/selectedcontent/input.svelte
 create mode 100644 packages/svelte/tests/hydration/samples/optgroup-rich-content/_config.js
 create mode 100644 packages/svelte/tests/hydration/samples/optgroup-rich-content/_expected.html
 create mode 100644 packages/svelte/tests/hydration/samples/optgroup-rich-content/main.svelte
 create mode 100644 packages/svelte/tests/hydration/samples/option-rich-content-continues/_config.js
 create mode 100644 packages/svelte/tests/hydration/samples/option-rich-content-continues/_expected.html
 create mode 100644 packages/svelte/tests/hydration/samples/option-rich-content-continues/main.svelte
 create mode 100644 packages/svelte/tests/hydration/samples/option-rich-content-static/_config.js
 create mode 100644 packages/svelte/tests/hydration/samples/option-rich-content-static/_expected.html
 create mode 100644 packages/svelte/tests/hydration/samples/option-rich-content-static/main.svelte
 create mode 100644 packages/svelte/tests/hydration/samples/rich-select/Option.svelte
 create mode 100644 packages/svelte/tests/hydration/samples/rich-select/_config.js
 create mode 100644 packages/svelte/tests/hydration/samples/rich-select/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/optgroup-rich-content/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/optgroup-rich-content/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/option-rich-content/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/option-rich-content/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/rich-option-component/Content.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/rich-option-component/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/rich-option-component/main.svelte
 create mode 100644 packages/svelte/tests/snapshot/samples/select-with-rich-content/Option.svelte
 create mode 100644 packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/Option.svelte.js
 create mode 100644 packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js
 create mode 100644 packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/server/Option.svelte.js
 create mode 100644 packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/server/index.svelte.js
 create mode 100644 packages/svelte/tests/snapshot/samples/select-with-rich-content/index.svelte

diff --git a/.changeset/chubby-dingos-laugh.md b/.changeset/chubby-dingos-laugh.md
new file mode 100644
index 0000000000..cd7b990e50
--- /dev/null
+++ b/.changeset/chubby-dingos-laugh.md
@@ -0,0 +1,5 @@
+---
+'svelte': minor
+---
+
+feat: customizable `<select>` elements
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 8a4d8cb350..7242c69d8c 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
@@ -770,7 +770,39 @@ function get_ancestor_elements(node, adjacent_only, seen = new Set()) {
 		}
 
 		if (parent.type === 'RegularElement' || parent.type === 'SvelteElement') {
+			// Special handling for <option> inside <select>: elements inside <option> should
+			// also be considered descendants of <selectedcontent>, which clones the selected option's content
+			if (parent.type === 'RegularElement' && parent.name === 'option') {
+				const is_direct_child = ancestors.length === 0;
+
+				const select_element = path.findLast(
+					(element, j) => element.type === 'RegularElement' && element.name === 'select' && j < i
+				);
+
+				if (select_element && (!adjacent_only || is_direct_child)) {
+					/** @type {Compiler.AST.RegularElement | null} */
+					let selectedcontent_element = null;
+					walk(select_element, null, {
+						RegularElement(child, context) {
+							if (child.name === 'selectedcontent') {
+								selectedcontent_element = child;
+								context.stop();
+								return;
+							}
+							context.next();
+						}
+					});
+
+					if (adjacent_only && is_direct_child && selectedcontent_element) {
+						return [selectedcontent_element, parent];
+					} else if (selectedcontent_element) {
+						ancestors.push(selectedcontent_element);
+					}
+				}
+			}
+
 			ancestors.push(parent);
+
 			if (adjacent_only) {
 				break;
 			}
@@ -817,6 +849,34 @@ function get_descendant_elements(node, adjacent_only, seen = new Set()) {
 
 	walk_children(node.type === 'RenderTag' ? node : node.fragment);
 
+	// Special handling for <selectedcontent>: it clones the content of the selected <option>,
+	// so descendants of <option> elements in the same <select> should also be considered descendants
+	if (node.type === 'RegularElement' && node.name === 'selectedcontent') {
+		const path = node.metadata.path;
+		const select_element = path.findLast(
+			(/** @type {Compiler.AST.SvelteNode} */ element) =>
+				element.type === 'RegularElement' && element.name === 'select'
+		);
+
+		if (select_element) {
+			walk(
+				select_element,
+				{ inside_option: false },
+				{
+					_(child, context) {
+						if (child.type === 'RegularElement' && child.name === 'option') {
+							context.next({ inside_option: true });
+						} else if (context.state.inside_option) {
+							walk_children(child);
+						} else {
+							context.next();
+						}
+					}
+				}
+			);
+		}
+	}
+
 	return descendants;
 }
 
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/RegularElement.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/RegularElement.js
index 5fce138089..1f3a93c67e 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/RegularElement.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/RegularElement.js
@@ -7,7 +7,11 @@ import {
 } from '../../../../html-tree-validation.js';
 import * as e from '../../../errors.js';
 import * as w from '../../../warnings.js';
-import { create_attribute, is_custom_element_node } from '../../nodes.js';
+import {
+	create_attribute,
+	is_custom_element_node,
+	is_customizable_select_element
+} from '../../nodes.js';
 import { regex_starts_with_newline } from '../../patterns.js';
 import { check_element } from './shared/a11y/index.js';
 import { validate_element } from './shared/element.js';
@@ -74,6 +78,15 @@ export function RegularElement(node, context) {
 		node.metadata.synthetic_value_node = child;
 	}
 
+	// Special case: <select>, <option> or <optgroup> with rich content needs special hydration handling
+	// We mark the subtree as dynamic so parent elements properly include the child init code
+	if (is_customizable_select_element(node)) {
+		// Mark the element's own fragment as dynamic so it's not treated as static
+		node.fragment.metadata.dynamic = true;
+		// Also mark ancestor fragments so parents properly include the child init code
+		mark_subtree_dynamic(context.path);
+	}
+
 	const binding = context.state.scope.get(node.name);
 	if (
 		binding !== null &&
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 717ee4bf50..50b107d068 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
@@ -831,6 +831,10 @@ function has_content(element) {
 				return true;
 			}
 
+			if (node.name === 'selectedcontent') {
+				return true;
+			}
+
 			if (!has_content(node)) {
 				continue;
 			}
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 c780350d3e..3b3cf4c325 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
@@ -11,7 +11,12 @@ import {
 import { is_ignored } from '../../../../state.js';
 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 } from '../../../nodes.js';
+import {
+	create_attribute,
+	ExpressionMetadata,
+	is_custom_element_node,
+	is_customizable_select_element
+} from '../../../nodes.js';
 import { clean_nodes, determine_namespace_for_children } from '../../utils.js';
 import { build_getter } from '../utils.js';
 import {
@@ -24,6 +29,9 @@ import {
 import { process_children, is_static_element } from './shared/fragment.js';
 import { build_render_statement, build_template_chunk, Memoizer } from './shared/utils.js';
 import { visit_event_attribute } from './shared/events.js';
+import { Template } from '../transform-template/template.js';
+import { transform_template } from '../transform-template/index.js';
+import { TEMPLATE_FRAGMENT } from '../../../../../constants.js';
 
 /**
  * @param {AST.RegularElement} node
@@ -351,6 +359,57 @@ export function RegularElement(node, context) {
 				b.stmt(b.assignment('=', b.member(context.state.node, 'textContent'), value))
 			);
 		}
+	} else if (is_customizable_select_element(node)) {
+		// For <option>, <optgroup>, or <select> elements with rich content, we need to branch based on browser support.
+		// Modern browsers preserve rich HTML in options, older browsers strip it to text only.
+		// We create a separate template for the rich content and append it to the element.
+
+		const element_node = context.state.node;
+
+		// Add a hydration marker inside the option element so $.child() has an anchor to find
+		context.state.template.push_comment();
+
+		// Create a separate template for the rich content
+		const template_name = context.state.scope.root.unique(`${node.name}_content`);
+		const fragment_id = b.id(context.state.scope.generate('fragment'));
+		const anchor_id = b.id(context.state.scope.generate('anchor'));
+
+		// Create state with a new template for the rich content
+		/** @type {typeof state} */
+		const select_state = {
+			...state,
+			init: [],
+			update: [],
+			after_update: [],
+			template: new Template()
+		};
+
+		process_children(
+			trimmed,
+			(is_text) => b.call('$.first_child', fragment_id, is_text && b.true),
+			false,
+			{
+				...context,
+				state: select_state
+			}
+		);
+
+		// Transform the template to $.from_html(...) and hoist it
+		const template = transform_template(select_state, metadata.namespace, TEMPLATE_FRAGMENT);
+		context.state.hoisted.push(b.var(template_name, template));
+
+		// Build the rich content function body
+		// The anchor is the child of the element (a hydration marker during hydration)
+		const body = b.block([
+			b.var(anchor_id, b.call('$.child', element_node)),
+			b.var(fragment_id, b.call(template_name)),
+			...select_state.init,
+			...(select_state.update.length > 0 ? [build_render_statement(select_state)] : []),
+			...select_state.after_update,
+			b.stmt(b.call('$.append', anchor_id, fragment_id))
+		]);
+
+		child_state.init.push(b.stmt(b.call('$.customizable_select', element_node, b.arrow([], body))));
 	} else {
 		/** @type {Expression} */
 		let arg = context.state.node;
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 f74b1185a0..79858b95d9 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
@@ -15,6 +15,7 @@ import {
 	PromiseOptimiser,
 	create_async_block
 } from './shared/utils.js';
+import { is_customizable_select_element } from '../../../nodes.js';
 
 /**
  * @param {AST.RegularElement} node
@@ -124,6 +125,10 @@ export function RegularElement(node, context) {
 
 		const [attributes, ...rest] = prepare_element_spread_object(node, context, optimiser.transform);
 
+		if (is_customizable_select_element(node)) {
+			rest.push(b.true);
+		}
+
 		const statement = b.stmt(b.call('$$renderer.select', attributes, fn, ...rest));
 
 		if (optimiser.expressions.length > 0) {
@@ -149,14 +154,34 @@ export function RegularElement(node, context) {
 			const inner_state = { ...state, template: [], init: [] };
 			process_children(trimmed, { ...context, state: inner_state });
 
-			body = b.arrow(
-				[b.id('$$renderer')],
-				b.block([...state.init, ...build_template(inner_state.template)])
-			);
+			/** @type {import('estree').Statement[]} */
+			const body_statements = [...state.init, ...build_template(inner_state.template)];
+
+			if (dev) {
+				const location = locator(node.start);
+				body_statements.unshift(
+					b.stmt(
+						b.call(
+							'$.push_element',
+							b.id('$$renderer'),
+							b.literal(node.name),
+							b.literal(location.line),
+							b.literal(location.column)
+						)
+					)
+				);
+				body_statements.push(b.stmt(b.call('$.pop_element')));
+			}
+
+			body = b.arrow([b.id('$$renderer')], b.block(body_statements));
 		}
 
 		const [attributes, ...rest] = prepare_element_spread_object(node, context, optimiser.transform);
 
+		if (is_customizable_select_element(node)) {
+			rest.push(b.true);
+		}
+
 		const statement = b.stmt(b.call('$$renderer.option', attributes, body, ...rest));
 
 		if (optimiser.expressions.length > 0) {
@@ -192,7 +217,14 @@ export function RegularElement(node, context) {
 			)
 		);
 	} else {
+		// For optgroup or select with rich content, add hydration marker at the start
 		process_children(trimmed, { ...context, state });
+		if (
+			(node.name === 'optgroup' || node.name === 'select') &&
+			is_customizable_select_element(node)
+		) {
+			state.template.push(b.literal('<!>'));
+		}
 	}
 
 	if (!node_is_void) {
diff --git a/packages/svelte/src/compiler/phases/nodes.js b/packages/svelte/src/compiler/phases/nodes.js
index 313880cf5b..f302603409 100644
--- a/packages/svelte/src/compiler/phases/nodes.js
+++ b/packages/svelte/src/compiler/phases/nodes.js
@@ -148,3 +148,98 @@ export function get_name(node) {
 
 	return null;
 }
+
+/**
+ * Checks if an <option>, <optgroup>, or <select> element has rich content that requires special hydration handling.
+ * Rich content is anything beyond simple text, expressions, and comments for <option>,
+ * anything beyond <option> children for <optgroup>,
+ * or anything beyond <option>, <optgroup>, and empty text for <select>.
+ * Control flow blocks are recursively checked - they only count as rich content if they contain rich content.
+ * @param {AST.RegularElement} node
+ * @returns {boolean}
+ */
+export function is_customizable_select_element(node) {
+	if (node.name === 'select' || node.name === 'optgroup' || node.name === 'option') {
+		for (const child of find_descendants(node.fragment)) {
+			if (child.type === 'RegularElement') {
+				if (node.name === 'select' && child.name !== 'option' && child.name !== 'optgroup') {
+					return true;
+				}
+
+				if (node.name === 'optgroup' && child.name !== 'option') {
+					return true;
+				}
+
+				if (node.name === 'option') {
+					return true;
+				}
+			}
+
+			// Text nodes directly in <select> or <optgroup> are rich content
+			else if (child.type === 'Text') {
+				if (node.name === 'select' || node.name === 'optgroup') {
+					return true;
+				}
+			}
+
+			// Any non-RegularElement, non-Text node is rich content
+			else {
+				return true;
+			}
+		}
+	}
+
+	return false;
+}
+
+/**
+ * @param {AST.Fragment | null} fragment
+ * @returns {Iterable<AST.SvelteNode>}
+ */
+function* find_descendants(fragment) {
+	if (fragment === null) return;
+
+	for (const node of fragment.nodes) {
+		switch (node.type) {
+			case 'SnippetBlock':
+			case 'DebugTag':
+			case 'ConstTag':
+			case 'Comment':
+			case 'ExpressionTag':
+				break;
+
+			case 'Text':
+				if (node.data.trim() !== '') {
+					yield node;
+				}
+				break;
+
+			case 'IfBlock':
+				yield* find_descendants(node.consequent);
+				yield* find_descendants(node.alternate);
+				break;
+
+			case 'EachBlock':
+				yield* find_descendants(node.body);
+				yield* find_descendants(node.fallback ?? null);
+				break;
+
+			case 'KeyBlock':
+				yield* find_descendants(node.fragment);
+				break;
+
+			case 'AwaitBlock':
+				yield* find_descendants(node.pending);
+				yield* find_descendants(node.then);
+				yield* find_descendants(node.catch);
+				break;
+
+			case 'SvelteBoundary':
+				yield* find_descendants(node.fragment);
+				break;
+
+			default:
+				yield node;
+		}
+	}
+}
diff --git a/packages/svelte/src/html-tree-validation.js b/packages/svelte/src/html-tree-validation.js
index 4ec4ecf26f..d05cb81a71 100644
--- a/packages/svelte/src/html-tree-validation.js
+++ b/packages/svelte/src/html-tree-validation.js
@@ -80,9 +80,9 @@ export function closing_tag_omitted(current, next) {
  */
 const disallowed_children = {
 	...autoclosing_children,
-	optgroup: { only: ['option', '#text'] },
 	// Strictly speaking, seeing an <option> doesn't mean we're in a <select>, but we assume it here
-	option: { only: ['#text'] },
+	// option or optgroup does not have an `only` restriction because newer browsers support rich HTML content
+	// inside option elements. For older browsers, hydration will handle the mismatch.
 	form: { descendant: ['form'] },
 	a: { descendant: ['a'] },
 	button: { descendant: ['button'] },
@@ -92,8 +92,6 @@ const disallowed_children = {
 	h4: { descendant: ['h1', 'h2', 'h3', 'h4', 'h5', 'h6'] },
 	h5: { descendant: ['h1', 'h2', 'h3', 'h4', 'h5', 'h6'] },
 	h6: { descendant: ['h1', 'h2', 'h3', 'h4', 'h5', 'h6'] },
-	// https://html.spec.whatwg.org/multipage/syntax.html#parsing-main-inselect
-	select: { only: ['option', 'optgroup', '#text', 'hr', 'script', 'template'] },
 
 	// https://html.spec.whatwg.org/multipage/syntax.html#parsing-main-intd
 	// https://html.spec.whatwg.org/multipage/syntax.html#parsing-main-incaption
diff --git a/packages/svelte/src/internal/client/dom/elements/customizable-select.js b/packages/svelte/src/internal/client/dom/elements/customizable-select.js
new file mode 100644
index 0000000000..5bf2144d1c
--- /dev/null
+++ b/packages/svelte/src/internal/client/dom/elements/customizable-select.js
@@ -0,0 +1,51 @@
+import { hydrating, reset, set_hydrate_node, set_hydrating } from '../hydration.js';
+import { create_comment } from '../operations.js';
+
+/** @type {boolean | null} */
+let supported = null;
+
+/**
+ * Checks if the browser supports rich HTML content inside `<option>` elements.
+ * Modern browsers preserve HTML elements inside options, while older browsers
+ * strip them during parsing, leaving only text content.
+ * @returns {boolean}
+ */
+function is_supported() {
+	if (supported === null) {
+		var select = document.createElement('select');
+		select.innerHTML = '<option><span>t</span></option>';
+		supported = /** @type {Element} */ (select.firstChild)?.firstChild?.nodeType === 1;
+	}
+
+	return supported;
+}
+
+/**
+ * Handles rich HTML content inside `<option>`, `<optgroup>`, or `<select>` elements with browser-specific branching.
+ * Modern browsers preserve HTML inside options, while older browsers strip it to text only.
+ *
+ * @param {HTMLOptionElement | HTMLOptGroupElement | HTMLSelectElement} element The element to process
+ * @param {() => void} rich_fn Function to process rich HTML content (modern browsers)
+ */
+export function customizable_select(element, rich_fn) {
+	var was_hydrating = hydrating;
+
+	if (!is_supported()) {
+		set_hydrating(false);
+		element.textContent = '';
+		element.append(create_comment(''));
+	}
+
+	try {
+		rich_fn();
+	} finally {
+		if (was_hydrating) {
+			if (hydrating) {
+				reset(element);
+			} else {
+				set_hydrating(true);
+				set_hydrate_node(element);
+			}
+		}
+	}
+}
diff --git a/packages/svelte/src/internal/client/index.js b/packages/svelte/src/internal/client/index.js
index a2666d8712..4792bc7230 100644
--- a/packages/svelte/src/internal/client/index.js
+++ b/packages/svelte/src/internal/client/index.js
@@ -42,6 +42,7 @@ export {
 export { set_class } from './dom/elements/class.js';
 export { apply, event, delegate, replay_events } from './dom/elements/events.js';
 export { autofocus, remove_textarea_child } from './dom/elements/misc.js';
+export { customizable_select } from './dom/elements/customizable-select.js';
 export { set_style } from './dom/elements/style.js';
 export { animation, transition } from './dom/elements/transitions.js';
 export { bind_active_element } from './dom/elements/bindings/document.js';
diff --git a/packages/svelte/src/internal/server/renderer.js b/packages/svelte/src/internal/server/renderer.js
index 82f8025759..4da0b05cfd 100644
--- a/packages/svelte/src/internal/server/renderer.js
+++ b/packages/svelte/src/internal/server/renderer.js
@@ -220,9 +220,10 @@ export class Renderer {
 	 * @param {Record<string, boolean> | undefined} [classes]
 	 * @param {Record<string, string> | undefined} [styles]
 	 * @param {number | undefined} [flags]
+	 * @param {boolean | undefined} [is_rich]
 	 * @returns {void}
 	 */
-	select(attrs, fn, css_hash, classes, styles, flags) {
+	select(attrs, fn, css_hash, classes, styles, flags, is_rich) {
 		const { value, ...select_attrs } = attrs;
 
 		this.push(`<select${attributes(select_attrs, css_hash, classes, styles, flags)}>`);
@@ -230,7 +231,7 @@ export class Renderer {
 			renderer.local.select_value = value;
 			fn(renderer);
 		});
-		this.push('</select>');
+		this.push(`${is_rich ? '<!>' : ''}</select>`);
 	}
 
 	/**
@@ -240,8 +241,9 @@ export class Renderer {
 	 * @param {Record<string, boolean> | undefined} [classes]
 	 * @param {Record<string, string> | undefined} [styles]
 	 * @param {number | undefined} [flags]
+	 * @param {boolean | undefined} [is_rich]
 	 */
-	option(attrs, body, css_hash, classes, styles, flags) {
+	option(attrs, body, css_hash, classes, styles, flags, is_rich) {
 		this.#out.push(`<option${attributes(attrs, css_hash, classes, styles, flags)}`);
 
 		/**
@@ -258,7 +260,7 @@ export class Renderer {
 				renderer.#out.push(' selected');
 			}
 
-			renderer.#out.push(`>${body}</option>`);
+			renderer.#out.push(`>${body}${is_rich ? '<!>' : ''}</option>`);
 
 			// super edge case, but may as well handle it
 			if (head) {
diff --git a/packages/svelte/tests/css/samples/selectedcontent/expected.css b/packages/svelte/tests/css/samples/selectedcontent/expected.css
new file mode 100644
index 0000000000..87b4e04de7
--- /dev/null
+++ b/packages/svelte/tests/css/samples/selectedcontent/expected.css
@@ -0,0 +1,44 @@
+
+	select.svelte-xyz,
+	.svelte-xyz::picker(select) {
+	  appearance: base-select;
+	}
+	selectedcontent.svelte-xyz b:where(.svelte-xyz){
+		color: red;
+	}
+	e.svelte-xyz{
+		selectedcontent:where(.svelte-xyz) &{
+			color: green;
+		}
+	}
+	select.svelte-xyz > button:where(.svelte-xyz) > selectedcontent:where(.svelte-xyz) > b:where(.svelte-xyz) {
+		color: blue;
+	}
+
+	select.svelte-xyz > button:where(.svelte-xyz) > selectedcontent:where(.svelte-xyz) i:where(.svelte-xyz) {
+		color: blue;
+	}
+
+	selectedcontent.svelte-xyz:has(b:where(.svelte-xyz)){
+		background-color: rebeccapurple;
+	}
+
+	selectedcontent.svelte-xyz:has(i:where(.svelte-xyz)){
+		background-color: rebeccapurple;
+	}
+
+	option.svelte-xyz > b:where(.svelte-xyz){
+		color: orange;
+	}
+
+	option.svelte-xyz b:where(.svelte-xyz){
+		color: #ff3e00;
+	}
+
+	option.svelte-xyz > b:where(.svelte-xyz) > i:where(.svelte-xyz){
+		text-decoration: underline;
+	}
+
+	option.svelte-xyz i:where(.svelte-xyz){
+		text-decoration: dashed;
+	}
diff --git a/packages/svelte/tests/css/samples/selectedcontent/input.svelte b/packages/svelte/tests/css/samples/selectedcontent/input.svelte
new file mode 100644
index 0000000000..b8305551d7
--- /dev/null
+++ b/packages/svelte/tests/css/samples/selectedcontent/input.svelte
@@ -0,0 +1,53 @@
+<select>
+	<button aria-label="Selected value">
+		<selectedcontent></selectedcontent>
+	</button>
+	<option>plain text</option>
+	<option><b>rich <i>italic</i></b><e>content</e></option>
+</select>
+
+<style>
+	select,
+	::picker(select) {
+	  appearance: base-select;
+	}
+	selectedcontent b{
+		color: red;
+	}
+	e{
+		selectedcontent &{
+			color: green;
+		}
+	}
+	select > button > selectedcontent > b {
+		color: blue;
+	}
+
+	select > button > selectedcontent i {
+		color: blue;
+	}
+
+	selectedcontent:has(b){
+		background-color: rebeccapurple;
+	}
+
+	selectedcontent:has(i){
+		background-color: rebeccapurple;
+	}
+
+	option > b{
+		color: orange;
+	}
+
+	option b{
+		color: #ff3e00;
+	}
+
+	option > b > i{
+		text-decoration: underline;
+	}
+
+	option i{
+		text-decoration: dashed;
+	}
+</style>
\ No newline at end of file
diff --git a/packages/svelte/tests/hydration/samples/optgroup-rich-content/_config.js b/packages/svelte/tests/hydration/samples/optgroup-rich-content/_config.js
new file mode 100644
index 0000000000..36ca2e6ae5
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/optgroup-rich-content/_config.js
@@ -0,0 +1,31 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	// This test verifies that hydration works correctly for
+	// optgroup elements with rich HTML content (non-option elements inside optgroup)
+	snapshot(target) {
+		const select = target.querySelector('select');
+
+		return {
+			select
+		};
+	},
+
+	async test(assert, target) {
+		const optgroup = target.querySelector('optgroup');
+		const options = target.querySelectorAll('option');
+		const button = target.querySelector('button');
+
+		// Check options content - the span inside optgroup gets stripped but text remains
+		assert.equal(options[0]?.textContent, 'hello hello');
+		assert.equal(options[1]?.textContent, 'Plain option');
+
+		// Update via button click
+		flushSync(() => {
+			button?.click();
+		});
+
+		assert.equal(options[0]?.textContent, 'changed changed');
+	}
+});
diff --git a/packages/svelte/tests/hydration/samples/optgroup-rich-content/_expected.html b/packages/svelte/tests/hydration/samples/optgroup-rich-content/_expected.html
new file mode 100644
index 0000000000..911b92770b
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/optgroup-rich-content/_expected.html
@@ -0,0 +1 @@
+<select><optgroup label="Fruits">hello <option value="a"><span>hello</span> hello</option><option value="b">Plain option</option></optgroup><optgroup label="Static Group"><option value="c">Another option</option></optgroup></select> <button></button>
diff --git a/packages/svelte/tests/hydration/samples/optgroup-rich-content/main.svelte b/packages/svelte/tests/hydration/samples/optgroup-rich-content/main.svelte
new file mode 100644
index 0000000000..227c4d56d5
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/optgroup-rich-content/main.svelte
@@ -0,0 +1,16 @@
+<script>
+	let label = $state('hello');
+</script>
+
+<select>
+	<optgroup label="Fruits">
+		<span class="group-header">{label}</span>
+		<option value="a"><span>{label}</span> {label}</option>
+		<option value="b">Plain option</option>
+	</optgroup>
+	<optgroup label="Static Group">
+		<option value="c">Another option</option>
+	</optgroup>
+</select>
+
+<button onclick={() => label = "changed"}></button>
diff --git a/packages/svelte/tests/hydration/samples/option-rich-content-continues/_config.js b/packages/svelte/tests/hydration/samples/option-rich-content-continues/_config.js
new file mode 100644
index 0000000000..a2163b7c67
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/option-rich-content-continues/_config.js
@@ -0,0 +1,34 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	// This test verifies that hydration continues correctly after
+	// an option element with rich HTML content
+	snapshot(target) {
+		const select = target.querySelector('select');
+		const options = target.querySelectorAll('option');
+		const p = target.querySelector('p');
+		const button = target.querySelector('button');
+
+		return {
+			select,
+			option1: options[0],
+			option2: options[1],
+			p,
+			button
+		};
+	},
+
+	async test(assert, target) {
+		const option = target.querySelector('option');
+		const button = target.querySelector('button');
+
+		assert.equal(option?.textContent, 'hello hello');
+
+		flushSync(() => {
+			button?.click();
+		});
+
+		assert.equal(option?.textContent, 'changed changed');
+	}
+});
diff --git a/packages/svelte/tests/hydration/samples/option-rich-content-continues/_expected.html b/packages/svelte/tests/hydration/samples/option-rich-content-continues/_expected.html
new file mode 100644
index 0000000000..d3e209c990
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/option-rich-content-continues/_expected.html
@@ -0,0 +1 @@
+<select><option value="a">hello hello</option><option value="b">Plain text</option></select> <button></button>
diff --git a/packages/svelte/tests/hydration/samples/option-rich-content-continues/main.svelte b/packages/svelte/tests/hydration/samples/option-rich-content-continues/main.svelte
new file mode 100644
index 0000000000..47edc28035
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/option-rich-content-continues/main.svelte
@@ -0,0 +1,12 @@
+<script>
+	let label = $state('hello');
+	let count = $state(42);
+</script>
+
+<select>
+	<!-- this would fail during hydration if rich_option handling is not correct -->
+	<option value="a"><span>{label}</span> {label}</option>
+	<option value="b">Plain text</option>
+</select>
+	
+<button onclick={() => label = "changed"}></button>
diff --git a/packages/svelte/tests/hydration/samples/option-rich-content-static/_config.js b/packages/svelte/tests/hydration/samples/option-rich-content-static/_config.js
new file mode 100644
index 0000000000..ca8c2b6ec1
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/option-rich-content-static/_config.js
@@ -0,0 +1,39 @@
+import { test } from '../../test';
+
+export default test({
+	// This test verifies that completely static select with rich option content
+	// hydrates correctly and the content is preserved
+	snapshot(target) {
+		const select = target.querySelector('select');
+		const options = target.querySelectorAll('option');
+
+		return {
+			select,
+			option1: options[0],
+			option2: options[1],
+			option3: options[2]
+		};
+	},
+
+	async test(assert, target) {
+		const options = target.querySelectorAll('option');
+
+		// Verify the rich content is present in the options
+		assert.equal(options[0]?.textContent, 'Bold Option');
+		assert.equal(options[1]?.textContent, 'Italic Option');
+		assert.equal(options[2]?.textContent, 'Plain Option');
+
+		// Check that the rich elements are actually there (on supporting browsers)
+		const strong = options[0]?.querySelector('strong');
+		const em = options[1]?.querySelector('em');
+
+		// These may or may not exist depending on browser support
+		// but the text content should always be correct
+		if (strong) {
+			assert.equal(strong.textContent, 'Bold');
+		}
+		if (em) {
+			assert.equal(em.textContent, 'Italic');
+		}
+	}
+});
diff --git a/packages/svelte/tests/hydration/samples/option-rich-content-static/_expected.html b/packages/svelte/tests/hydration/samples/option-rich-content-static/_expected.html
new file mode 100644
index 0000000000..93cfa49dd1
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/option-rich-content-static/_expected.html
@@ -0,0 +1 @@
+<select><option value="a"><strong>Bold</strong> Option</option><option value="b"><em>Italic</em> Option</option><option value="c">Plain Option</option></select>
diff --git a/packages/svelte/tests/hydration/samples/option-rich-content-static/main.svelte b/packages/svelte/tests/hydration/samples/option-rich-content-static/main.svelte
new file mode 100644
index 0000000000..bd81687434
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/option-rich-content-static/main.svelte
@@ -0,0 +1,5 @@
+<select>
+	<option value="a"><strong>Bold</strong> Option</option>
+	<option value="b"><em>Italic</em> Option</option>
+	<option value="c">Plain Option</option>
+</select>
diff --git a/packages/svelte/tests/hydration/samples/rich-select/Option.svelte b/packages/svelte/tests/hydration/samples/rich-select/Option.svelte
new file mode 100644
index 0000000000..783915d571
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/rich-select/Option.svelte
@@ -0,0 +1 @@
+<option>Option component</option>
\ No newline at end of file
diff --git a/packages/svelte/tests/hydration/samples/rich-select/_config.js b/packages/svelte/tests/hydration/samples/rich-select/_config.js
new file mode 100644
index 0000000000..f47bee71df
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/rich-select/_config.js
@@ -0,0 +1,3 @@
+import { test } from '../../test';
+
+export default test({});
diff --git a/packages/svelte/tests/hydration/samples/rich-select/main.svelte b/packages/svelte/tests/hydration/samples/rich-select/main.svelte
new file mode 100644
index 0000000000..bb77d8e57a
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/rich-select/main.svelte
@@ -0,0 +1,173 @@
+<script>
+	let items = [1, 2, 3];
+	let show = true;
+	let html = '<option>From HTML</option>';
+
+	import Option from './Option.svelte';
+</script>
+
+<!-- select with rich option (has span inside) - SHOULD use customizable_select_element -->
+<select>
+	<option><span>Rich</span></option>
+</select>
+
+<!-- select with each containing plain options - should NOT use customizable_select_element -->
+<select>
+	{#each items as item}
+		<option>{item}</option>
+	{/each}
+</select>
+
+<!-- select with if containing plain options - should NOT use customizable_select_element -->
+<select>
+	{#if show}
+		<option>Visible</option>
+	{/if}
+</select>
+
+<!-- select with key containing plain options - should NOT use customizable_select_element -->
+<select>
+	{#key items}
+		<option>Keyed</option>
+	{/key}
+</select>
+
+<!-- select with snippet defined at top level and rendered - should NOT use customizable_select_element -->
+{#snippet opt()}
+	<option>Snippet</option>
+{/snippet}
+<select>
+	{@render opt()}
+</select>
+
+<!-- select with const inside each (should be ignored) - should NOT use customizable_select_element -->
+<select>
+	{#each items as item}
+		{@const x = item * 2}
+		<option>{x}</option>
+	{/each}
+</select>
+
+<!-- optgroup with rich option - SHOULD use customizable_select_element -->
+<select>
+	<optgroup label="Group">
+		<option><strong>Bold</strong></option>
+	</optgroup>
+</select>
+
+<!-- optgroup with each containing plain options - should NOT use customizable_select_element -->
+<select>
+	<optgroup label="Group">
+		{#each items as item}
+			<option>{item}</option>
+		{/each}
+	</optgroup>
+</select>
+
+<!-- option with rich content (span) - SHOULD use customizable_select_element -->
+<select>
+	<option value="a"><em>Italic</em> text</option>
+</select>
+
+<!-- nested: select > each > option with rich content - SHOULD use customizable_select_element on option -->
+<select>
+	{#each items as item}
+		<option><span>{item}</span></option>
+	{/each}
+</select>
+
+<!-- nested: select > if > each > plain options - should NOT use customizable_select_element -->
+<select>
+	{#if show}
+		{#each items as item}
+			<option>{item}</option>
+		{/each}
+	{/if}
+</select>
+
+<!-- select with svelte:boundary containing plain options - should NOT use customizable_select_element -->
+<select>
+	<svelte:boundary>
+		<option>Boundary</option>
+	</svelte:boundary>
+</select>
+
+<!-- select with svelte:boundary containing rich options - SHOULD use customizable_select_element on option -->
+<select>
+	<svelte:boundary>
+		<option><span>Rich in boundary</span></option>
+	</svelte:boundary>
+</select>
+
+<!-- select with Component - SHOULD be treated as rich content -->
+<select>
+	<Option />
+</select>
+
+<!-- select with @render snippet - SHOULD be treated as rich content -->
+{#snippet option_snippet()}
+	<option>Rendered</option>
+{/snippet}
+<select>
+	{@render option_snippet()}
+</select>
+
+<!-- select with @html - SHOULD be treated as rich content -->
+<select>
+	{@html html}
+</select>
+
+<!-- optgroup with Component - SHOULD be treated as rich content -->
+<select>
+	<optgroup label="Group">
+		<Option />
+	</optgroup>
+</select>
+
+<!-- optgroup with @render - SHOULD be treated as rich content -->
+{#snippet option_snippet2()}
+	<option>Rendered in group</option>
+{/snippet}
+<select>
+	<optgroup label="Group">
+		{@render option_snippet2()}
+	</optgroup>
+</select>
+
+<!-- option with @html inside - SHOULD use customizable_select_element -->
+<select>
+	<option>{@html '<strong>Bold HTML</strong>'}</option>
+</select>
+
+<!-- each block inside select with Component - SHOULD be treated as rich -->
+<select>
+	{#each items as item}
+		<Option />
+	{/each}
+</select>
+
+<!-- if block inside select with @render - SHOULD be treated as rich -->
+{#snippet conditional_option()}
+	<option>Conditional</option>
+{/snippet}
+<select>
+	{#if show}
+		{@render conditional_option()}
+	{/if}
+</select>
+
+<!-- select with button/selectedcontent and static options - SHOULD use customizable_select_element -->
+<select>
+	<button><selectedcontent></selectedcontent></button>
+	<option>cool</option>
+	<option>cooler</option>
+	<option>coolerone</option>
+</select>
+
+<!-- select with button/selectedcontent and dynamic options - SHOULD use customizable_select_element -->
+<select>
+	<button><selectedcontent></selectedcontent></button>
+	{#each items as item}
+		<option>{item}</option>
+	{/each}
+</select>
diff --git a/packages/svelte/tests/runtime-runes/samples/optgroup-rich-content/_config.js b/packages/svelte/tests/runtime-runes/samples/optgroup-rich-content/_config.js
new file mode 100644
index 0000000000..9de60bcb56
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/optgroup-rich-content/_config.js
@@ -0,0 +1,31 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+// Test that optgroup with rich HTML content (non-option elements) and dynamic expressions works correctly
+export default test({
+	mode: ['client', 'hydrate'],
+	test({ assert, target }) {
+		const select = /** @type {HTMLSelectElement} */ (target.querySelector('select'));
+		const optgroups = target.querySelectorAll('optgroup');
+		const options = target.querySelectorAll('option');
+		const button = /** @type {HTMLButtonElement} */ (target.querySelector('button'));
+
+		assert.ok(select);
+		assert.equal(optgroups.length, 2);
+		assert.equal(options.length, 4);
+
+		// Check initial option content (rich content inside optgroup)
+		assert.equal(options[0]?.textContent, 'apple apple');
+		assert.equal(options[1]?.textContent, 'banana');
+		assert.equal(options[2]?.textContent, 'carrot carrot');
+		assert.equal(options[3]?.textContent, 'Plain celery');
+
+		// Click button to change dynamic content
+		button.click();
+		flushSync();
+
+		// Check updated option content
+		assert.equal(options[0]?.textContent, 'orange orange');
+		assert.equal(options[2]?.textContent, 'broccoli broccoli');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/optgroup-rich-content/main.svelte b/packages/svelte/tests/runtime-runes/samples/optgroup-rich-content/main.svelte
new file mode 100644
index 0000000000..03777a1cfb
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/optgroup-rich-content/main.svelte
@@ -0,0 +1,19 @@
+<script>
+	let fruit = $state('apple');
+	let vegetable = $state('carrot');
+</script>
+
+<select>
+	<optgroup label="Fruits">
+		<span class="fruits-header">{fruit}</span>
+		<option value="a"><span>{fruit}</span> {fruit}</option>
+		<option value="b">banana</option>
+	</optgroup>
+	<optgroup label="Vegetables">
+		<em class="veggies-header">{vegetable}</em>
+		<option value="c"><em>{vegetable}</em> {vegetable}</option>
+		<option value="d">Plain celery</option>
+	</optgroup>
+</select>
+
+<button onclick={() => { fruit = 'orange'; vegetable = 'broccoli'; }}>Change</button>
diff --git a/packages/svelte/tests/runtime-runes/samples/option-rich-content/_config.js b/packages/svelte/tests/runtime-runes/samples/option-rich-content/_config.js
new file mode 100644
index 0000000000..3c9e5847cd
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/option-rich-content/_config.js
@@ -0,0 +1,37 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+// Test that rich HTML content in <option> elements compiles without errors
+// and that the component functions correctly (on browsers that support it)
+export default test({
+	mode: ['client'],
+	test({ assert, target }) {
+		const select = /** @type {HTMLSelectElement} */ (target.querySelector('select'));
+		const p = /** @type {HTMLParagraphElement} */ (target.querySelector('p'));
+		const button = /** @type {HTMLButtonElement} */ (target.querySelector('button'));
+
+		assert.ok(select);
+		assert.ok(p);
+		assert.ok(button);
+		assert.equal(select.value, 'a');
+		assert.equal(p.textContent, 'Selected: a');
+
+		// Verify options exist
+		assert.equal(select.options.length, 3);
+
+		// Change selection
+		select.value = 'b';
+		select.dispatchEvent(new Event('change'));
+		flushSync();
+
+		assert.equal(p.textContent, 'Selected: b');
+
+		// Test reactivity of content within option (only works on browsers that support rich options)
+		// On modern browsers, clicking the button should update the text inside the span
+		button.click();
+		flushSync();
+
+		// The option text content should be updated on browsers that support rich options
+		// For this test, we just verify the component doesn't crash
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/option-rich-content/main.svelte b/packages/svelte/tests/runtime-runes/samples/option-rich-content/main.svelte
new file mode 100644
index 0000000000..37351ab058
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/option-rich-content/main.svelte
@@ -0,0 +1,15 @@
+<script>
+	let selected = $state('a');
+	let label_a = $state('Option');
+	let label_b = $state('Strong');
+</script>
+
+<select bind:value={selected}>
+	<option value="a"><span>{label_a}</span> A</option>
+	<option value="b"><strong>{label_b}</strong> B</option>
+	<option value="c">Plain C</option>
+</select>
+
+<p>Selected: {selected}</p>
+
+<button onclick={() => label_a = 'Changed'}>Change A</button>
diff --git a/packages/svelte/tests/runtime-runes/samples/rich-option-component/Content.svelte b/packages/svelte/tests/runtime-runes/samples/rich-option-component/Content.svelte
new file mode 100644
index 0000000000..437ab3e793
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/rich-option-component/Content.svelte
@@ -0,0 +1,5 @@
+<script>
+	let { text } = $props();
+</script>
+
+<span>{text}</span>
diff --git a/packages/svelte/tests/runtime-runes/samples/rich-option-component/_config.js b/packages/svelte/tests/runtime-runes/samples/rich-option-component/_config.js
new file mode 100644
index 0000000000..39d0db6590
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/rich-option-component/_config.js
@@ -0,0 +1,26 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+// Test that components can be used inside <option> elements.
+// This tests two scenarios:
+// 1. A component that wraps the entire <option> element
+// 2. A component used as content inside an <option> element
+//
+// In jsdom (which doesn't support rich options), the HTML content is stripped,
+// so we only verify the component doesn't crash and values work correctly.
+export default test({
+	test({ assert, target }) {
+		const option1 = target.querySelector('option');
+		const button = target.querySelector('button');
+
+		assert.ok(option1);
+
+		assert.equal(option1?.textContent, 'bb');
+
+		flushSync(() => {
+			button?.click();
+		});
+
+		assert.equal(option1?.textContent, 'aa');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/rich-option-component/main.svelte b/packages/svelte/tests/runtime-runes/samples/rich-option-component/main.svelte
new file mode 100644
index 0000000000..aed1342dfd
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/rich-option-component/main.svelte
@@ -0,0 +1,15 @@
+<script>
+	import Content from './Content.svelte';
+
+	let content = $state('b');
+</script>
+
+
+<!-- Test 2: Option with component as content -->
+<select>
+	<option value="x"><span>{content}</span><Content text={content} /></option>
+</select>
+
+<button onclick={() => content = content === 'a' ? 'b' : 'a'}>
+	Toggle Content
+</button>
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/select-with-rich-content/Option.svelte b/packages/svelte/tests/snapshot/samples/select-with-rich-content/Option.svelte
new file mode 100644
index 0000000000..89c9c1c111
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/select-with-rich-content/Option.svelte
@@ -0,0 +1 @@
+<option>Component Option</option>
diff --git a/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/Option.svelte.js b/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/Option.svelte.js
new file mode 100644
index 0000000000..a4b18a011b
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/Option.svelte.js
@@ -0,0 +1,11 @@
+import 'svelte/internal/disclose-version';
+import 'svelte/internal/flags/legacy';
+import * as $ from 'svelte/internal/client';
+
+var root = $.from_html(`<option>Component Option</option>`);
+
+export default function Option($$anchor) {
+	var option = root();
+
+	$.append($$anchor, option);
+}
\ No newline at end of file
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
new file mode 100644
index 0000000000..8f8b115d70
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/client/index.svelte.js
@@ -0,0 +1,412 @@
+import 'svelte/internal/disclose-version';
+import 'svelte/internal/flags/legacy';
+import * as $ from 'svelte/internal/client';
+import Option from './Option.svelte';
+
+const opt = ($$anchor) => {
+	var option = root_1();
+
+	$.append($$anchor, option);
+};
+
+const option_snippet = ($$anchor) => {
+	var option_1 = root_2();
+
+	$.append($$anchor, option_1);
+};
+
+const option_snippet2 = ($$anchor) => {
+	var option_2 = root_3();
+
+	$.append($$anchor, option_2);
+};
+
+const conditional_option = ($$anchor) => {
+	var option_3 = root_4();
+
+	$.append($$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 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 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 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);
+
+export default function Select_with_rich_content($$anchor) {
+	let items = [1, 2, 3];
+	let show = true;
+	let html = '<option>From HTML</option>';
+	var fragment = root();
+	var select = $.first_child(fragment);
+	var option_4 = $.child(select);
+
+	$.customizable_select(option_4, () => {
+		var anchor = $.child(option_4);
+		var fragment_1 = option_content();
+
+		$.append(anchor, fragment_1);
+	});
+
+	$.reset(select);
+
+	var select_1 = $.sibling(select, 2);
+
+	$.each(select_1, 5, () => items, $.index, ($$anchor, item) => {
+		var option_5 = root_5();
+		var text = $.child(option_5, true);
+
+		$.reset(option_5);
+
+		var option_5_value = {};
+
+		$.template_effect(() => {
+			$.set_text(text, $.get(item));
+
+			if (option_5_value !== (option_5_value = $.get(item))) {
+				option_5.__value = $.get(item);
+			}
+		});
+
+		$.append($$anchor, option_5);
+	});
+
+	$.reset(select_1);
+
+	var select_2 = $.sibling(select_1, 2);
+	var node = $.child(select_2);
+
+	{
+		var consequent = ($$anchor) => {
+			var option_6 = root_6();
+
+			$.append($$anchor, option_6);
+		};
+
+		$.if(node, ($$render) => {
+			if (show) $$render(consequent);
+		});
+	}
+
+	$.reset(select_2);
+
+	var select_3 = $.sibling(select_2, 2);
+	var node_1 = $.child(select_3);
+
+	$.key(node_1, () => items, ($$anchor) => {
+		var option_7 = root_7();
+
+		$.append($$anchor, option_7);
+	});
+
+	$.reset(select_3);
+
+	var select_4 = $.sibling(select_3, 2);
+
+	$.customizable_select(select_4, () => {
+		var anchor_1 = $.child(select_4);
+		var fragment_2 = select_content();
+		var node_2 = $.first_child(fragment_2);
+
+		opt(node_2);
+		$.append(anchor_1, fragment_2);
+	});
+
+	var select_5 = $.sibling(select_4, 2);
+
+	$.each(select_5, 5, () => items, $.index, ($$anchor, item) => {
+		const x = $.derived_safe_equal(() => $.get(item) * 2);
+		var option_8 = root_8();
+		var text_1 = $.child(option_8, true);
+
+		$.reset(option_8);
+
+		var option_8_value = {};
+
+		$.template_effect(() => {
+			$.set_text(text_1, $.get(x));
+
+			if (option_8_value !== (option_8_value = $.get(x))) {
+				option_8.__value = $.get(x);
+			}
+		});
+
+		$.append($$anchor, option_8);
+	});
+
+	$.reset(select_5);
+
+	var select_6 = $.sibling(select_5, 2);
+	var optgroup = $.child(select_6);
+	var option_9 = $.child(optgroup);
+
+	$.customizable_select(option_9, () => {
+		var anchor_2 = $.child(option_9);
+		var fragment_3 = option_content_1();
+
+		$.append(anchor_2, fragment_3);
+	});
+
+	$.reset(optgroup);
+	$.reset(select_6);
+
+	var select_7 = $.sibling(select_6, 2);
+	var optgroup_1 = $.child(select_7);
+
+	$.each(optgroup_1, 5, () => items, $.index, ($$anchor, item) => {
+		var option_10 = root_9();
+		var text_2 = $.child(option_10, true);
+
+		$.reset(option_10);
+
+		var option_10_value = {};
+
+		$.template_effect(() => {
+			$.set_text(text_2, $.get(item));
+
+			if (option_10_value !== (option_10_value = $.get(item))) {
+				option_10.__value = $.get(item);
+			}
+		});
+
+		$.append($$anchor, option_10);
+	});
+
+	$.reset(optgroup_1);
+	$.reset(select_7);
+
+	var select_8 = $.sibling(select_7, 2);
+	var option_11 = $.child(select_8);
+
+	$.customizable_select(option_11, () => {
+		var anchor_3 = $.child(option_11);
+		var fragment_4 = option_content_2();
+
+		$.next();
+		$.append(anchor_3, fragment_4);
+	});
+
+	option_11.value = option_11.__value = 'a';
+	$.reset(select_8);
+
+	var select_9 = $.sibling(select_8, 2);
+
+	$.each(select_9, 5, () => items, $.index, ($$anchor, item) => {
+		var option_12 = root_10();
+
+		$.customizable_select(option_12, () => {
+			var anchor_4 = $.child(option_12);
+			var fragment_5 = option_content_3();
+			var span = $.first_child(fragment_5);
+			var text_3 = $.child(span, true);
+
+			$.reset(span);
+			$.template_effect(() => $.set_text(text_3, $.get(item)));
+			$.append(anchor_4, fragment_5);
+		});
+
+		$.append($$anchor, option_12);
+	});
+
+	$.reset(select_9);
+
+	var select_10 = $.sibling(select_9, 2);
+	var node_3 = $.child(select_10);
+
+	{
+		var consequent_1 = ($$anchor) => {
+			var fragment_6 = $.comment();
+			var node_4 = $.first_child(fragment_6);
+
+			$.each(node_4, 1, () => items, $.index, ($$anchor, item) => {
+				var option_13 = root_12();
+				var text_4 = $.child(option_13, true);
+
+				$.reset(option_13);
+
+				var option_13_value = {};
+
+				$.template_effect(() => {
+					$.set_text(text_4, $.get(item));
+
+					if (option_13_value !== (option_13_value = $.get(item))) {
+						option_13.__value = $.get(item);
+					}
+				});
+
+				$.append($$anchor, option_13);
+			});
+
+			$.append($$anchor, fragment_6);
+		};
+
+		$.if(node_3, ($$render) => {
+			if (show) $$render(consequent_1);
+		});
+	}
+
+	$.reset(select_10);
+
+	var select_11 = $.sibling(select_10, 2);
+	var node_5 = $.child(select_11);
+
+	$.boundary(node_5, {}, ($$anchor) => {
+		var option_14 = root_13();
+
+		$.append($$anchor, option_14);
+	});
+
+	$.reset(select_11);
+
+	var select_12 = $.sibling(select_11, 2);
+	var node_6 = $.child(select_12);
+
+	$.boundary(node_6, {}, ($$anchor) => {
+		var option_15 = root_14();
+
+		$.customizable_select(option_15, () => {
+			var anchor_5 = $.child(option_15);
+			var fragment_7 = option_content_4();
+
+			$.append(anchor_5, fragment_7);
+		});
+
+		$.append($$anchor, option_15);
+	});
+
+	$.reset(select_12);
+
+	var select_13 = $.sibling(select_12, 2);
+
+	$.customizable_select(select_13, () => {
+		var anchor_6 = $.child(select_13);
+		var fragment_8 = select_content_1();
+		var node_7 = $.first_child(fragment_8);
+
+		Option(node_7, {});
+		$.append(anchor_6, fragment_8);
+	});
+
+	var select_14 = $.sibling(select_13, 2);
+
+	$.customizable_select(select_14, () => {
+		var anchor_7 = $.child(select_14);
+		var fragment_9 = select_content_2();
+		var node_8 = $.first_child(fragment_9);
+
+		option_snippet(node_8);
+		$.append(anchor_7, fragment_9);
+	});
+
+	var select_15 = $.sibling(select_14, 2);
+
+	$.customizable_select(select_15, () => {
+		var anchor_8 = $.child(select_15);
+		var fragment_10 = select_content_3();
+		var node_9 = $.first_child(fragment_10);
+
+		$.html(node_9, () => html);
+		$.append(anchor_8, fragment_10);
+	});
+
+	var select_16 = $.sibling(select_15, 2);
+	var optgroup_2 = $.child(select_16);
+
+	$.customizable_select(optgroup_2, () => {
+		var anchor_9 = $.child(optgroup_2);
+		var fragment_11 = optgroup_content();
+		var node_10 = $.first_child(fragment_11);
+
+		Option(node_10, {});
+		$.append(anchor_9, fragment_11);
+	});
+
+	$.reset(select_16);
+
+	var select_17 = $.sibling(select_16, 2);
+	var optgroup_3 = $.child(select_17);
+
+	$.customizable_select(optgroup_3, () => {
+		var anchor_10 = $.child(optgroup_3);
+		var fragment_12 = optgroup_content_1();
+		var node_11 = $.first_child(fragment_12);
+
+		option_snippet2(node_11);
+		$.append(anchor_10, fragment_12);
+	});
+
+	$.reset(select_17);
+
+	var select_18 = $.sibling(select_17, 2);
+	var option_16 = $.child(select_18);
+
+	$.customizable_select(option_16, () => {
+		var anchor_11 = $.child(option_16);
+		var fragment_13 = option_content_5();
+		var node_12 = $.first_child(fragment_13);
+
+		$.html(node_12, () => '<strong>Bold HTML</strong>');
+		$.append(anchor_11, fragment_13);
+	});
+
+	$.reset(select_18);
+
+	var select_19 = $.sibling(select_18, 2);
+
+	$.customizable_select(select_19, () => {
+		var anchor_12 = $.child(select_19);
+		var fragment_14 = select_content_4();
+		var node_13 = $.first_child(fragment_14);
+
+		$.each(node_13, 1, () => items, $.index, ($$anchor, item) => {
+			Option($$anchor, {});
+		});
+
+		$.append(anchor_12, fragment_14);
+	});
+
+	var select_20 = $.sibling(select_19, 2);
+
+	$.customizable_select(select_20, () => {
+		var anchor_13 = $.child(select_20);
+		var fragment_16 = select_content_5();
+		var node_14 = $.first_child(fragment_16);
+
+		{
+			var consequent_2 = ($$anchor) => {
+				conditional_option($$anchor);
+			};
+
+			$.if(node_14, ($$render) => {
+				if (show) $$render(consequent_2);
+			});
+		}
+
+		$.append(anchor_13, fragment_16);
+	});
+
+	$.append($$anchor, fragment);
+}
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/server/Option.svelte.js b/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/server/Option.svelte.js
new file mode 100644
index 0000000000..1c76c9493b
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/server/Option.svelte.js
@@ -0,0 +1,7 @@
+import * as $ from 'svelte/internal/server';
+
+export default function Option($$renderer) {
+	$$renderer.option({}, ($$renderer) => {
+		$$renderer.push(`Component Option`);
+	});
+}
\ No newline at end of file
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
new file mode 100644
index 0000000000..acf873ac09
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/select-with-rich-content/_expected/server/index.svelte.js
@@ -0,0 +1,233 @@
+import * as $ from 'svelte/internal/server';
+import Option from './Option.svelte';
+
+function opt($$renderer) {
+	$$renderer.option({}, ($$renderer) => {
+		$$renderer.push(`Snippet`);
+	});
+}
+
+function option_snippet($$renderer) {
+	$$renderer.option({}, ($$renderer) => {
+		$$renderer.push(`Rendered`);
+	});
+}
+
+function option_snippet2($$renderer) {
+	$$renderer.option({}, ($$renderer) => {
+		$$renderer.push(`Rendered in group`);
+	});
+}
+
+function conditional_option($$renderer) {
+	$$renderer.option({}, ($$renderer) => {
+		$$renderer.push(`Conditional`);
+	});
+}
+
+export default function Select_with_rich_content($$renderer) {
+	let items = [1, 2, 3];
+	let show = true;
+	let html = '<option>From HTML</option>';
+
+	$$renderer.push(`<select>`);
+
+	$$renderer.option(
+		{},
+		($$renderer) => {
+			$$renderer.push(`<span>Rich</span>`);
+		},
+		void 0,
+		void 0,
+		void 0,
+		void 0,
+		true
+	);
+
+	$$renderer.push(`</select> <select><!--[-->`);
+
+	const each_array = $.ensure_array_like(items);
+
+	for (let $$index = 0, $$length = each_array.length; $$index < $$length; $$index++) {
+		let item = each_array[$$index];
+
+		$$renderer.option({}, item);
+	}
+
+	$$renderer.push(`<!--]--></select> <select>`);
+
+	if (show) {
+		$$renderer.push('<!--[-->');
+
+		$$renderer.option({}, ($$renderer) => {
+			$$renderer.push(`Visible`);
+		});
+	} else {
+		$$renderer.push('<!--[!-->');
+	}
+
+	$$renderer.push(`<!--]--></select> <select><!---->`);
+
+	{
+		$$renderer.option({}, ($$renderer) => {
+			$$renderer.push(`Keyed`);
+		});
+	}
+
+	$$renderer.push(`<!----></select>  <select>`);
+	opt($$renderer);
+	$$renderer.push(`<!----><!></select> <select><!--[-->`);
+
+	const each_array_1 = $.ensure_array_like(items);
+
+	for (let $$index_1 = 0, $$length = each_array_1.length; $$index_1 < $$length; $$index_1++) {
+		let item = each_array_1[$$index_1];
+		const x = item * 2;
+
+		$$renderer.option({}, x);
+	}
+
+	$$renderer.push(`<!--]--></select> <select><optgroup label="Group">`);
+
+	$$renderer.option(
+		{},
+		($$renderer) => {
+			$$renderer.push(`<strong>Bold</strong>`);
+		},
+		void 0,
+		void 0,
+		void 0,
+		void 0,
+		true
+	);
+
+	$$renderer.push(`</optgroup></select> <select><optgroup label="Group"><!--[-->`);
+
+	const each_array_2 = $.ensure_array_like(items);
+
+	for (let $$index_2 = 0, $$length = each_array_2.length; $$index_2 < $$length; $$index_2++) {
+		let item = each_array_2[$$index_2];
+
+		$$renderer.option({}, item);
+	}
+
+	$$renderer.push(`<!--]--></optgroup></select> <select>`);
+
+	$$renderer.option(
+		{ value: 'a' },
+		($$renderer) => {
+			$$renderer.push(`<em>Italic</em> text`);
+		},
+		void 0,
+		void 0,
+		void 0,
+		void 0,
+		true
+	);
+
+	$$renderer.push(`</select> <select><!--[-->`);
+
+	const each_array_3 = $.ensure_array_like(items);
+
+	for (let $$index_3 = 0, $$length = each_array_3.length; $$index_3 < $$length; $$index_3++) {
+		let item = each_array_3[$$index_3];
+
+		$$renderer.option(
+			{},
+			($$renderer) => {
+				$$renderer.push(`<span>${$.escape(item)}</span>`);
+			},
+			void 0,
+			void 0,
+			void 0,
+			void 0,
+			true
+		);
+	}
+
+	$$renderer.push(`<!--]--></select> <select>`);
+
+	if (show) {
+		$$renderer.push('<!--[-->');
+		$$renderer.push(`<!--[-->`);
+
+		const each_array_4 = $.ensure_array_like(items);
+
+		for (let $$index_4 = 0, $$length = each_array_4.length; $$index_4 < $$length; $$index_4++) {
+			let item = each_array_4[$$index_4];
+
+			$$renderer.option({}, item);
+		}
+
+		$$renderer.push(`<!--]-->`);
+	} else {
+		$$renderer.push('<!--[!-->');
+	}
+
+	$$renderer.push(`<!--]--></select> <select><!--[-->`);
+
+	{
+		$$renderer.option({}, ($$renderer) => {
+			$$renderer.push(`Boundary`);
+		});
+	}
+
+	$$renderer.push(`<!--]--></select> <select><!--[-->`);
+
+	{
+		$$renderer.option(
+			{},
+			($$renderer) => {
+				$$renderer.push(`<span>Rich in boundary</span>`);
+			},
+			void 0,
+			void 0,
+			void 0,
+			void 0,
+			true
+		);
+	}
+
+	$$renderer.push(`<!--]--></select> <select>`);
+	Option($$renderer, {});
+	$$renderer.push(`<!----><!></select>  <select>`);
+	option_snippet($$renderer);
+	$$renderer.push(`<!----><!></select> <select>${$.html(html)}<!></select> <select><optgroup label="Group">`);
+	Option($$renderer, {});
+	$$renderer.push(`<!----><!></optgroup></select>  <select><optgroup label="Group">`);
+	option_snippet2($$renderer);
+	$$renderer.push(`<!----><!></optgroup></select> <select>`);
+
+	$$renderer.option(
+		{},
+		($$renderer) => {
+			$$renderer.push(`${$.html('<strong>Bold HTML</strong>')}`);
+		},
+		void 0,
+		void 0,
+		void 0,
+		void 0,
+		true
+	);
+
+	$$renderer.push(`</select> <select><!--[-->`);
+
+	const each_array_5 = $.ensure_array_like(items);
+
+	for (let $$index_5 = 0, $$length = each_array_5.length; $$index_5 < $$length; $$index_5++) {
+		let item = each_array_5[$$index_5];
+
+		Option($$renderer, {});
+	}
+
+	$$renderer.push(`<!--]--><!></select>  <select>`);
+
+	if (show) {
+		$$renderer.push('<!--[-->');
+		conditional_option($$renderer);
+	} else {
+		$$renderer.push('<!--[!-->');
+	}
+
+	$$renderer.push(`<!--]--><!></select>`);
+}
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/select-with-rich-content/index.svelte b/packages/svelte/tests/snapshot/samples/select-with-rich-content/index.svelte
new file mode 100644
index 0000000000..0363bf6a96
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/select-with-rich-content/index.svelte
@@ -0,0 +1,157 @@
+<script>
+	let items = [1, 2, 3];
+	let show = true;
+	let html = '<option>From HTML</option>';
+
+	import Option from './Option.svelte';
+</script>
+
+<!-- select with rich option (has span inside) - SHOULD use customizable_select_element -->
+<select>
+	<option><span>Rich</span></option>
+</select>
+
+<!-- select with each containing plain options - should NOT use customizable_select_element -->
+<select>
+	{#each items as item}
+		<option>{item}</option>
+	{/each}
+</select>
+
+<!-- select with if containing plain options - should NOT use customizable_select_element -->
+<select>
+	{#if show}
+		<option>Visible</option>
+	{/if}
+</select>
+
+<!-- select with key containing plain options - should NOT use customizable_select_element -->
+<select>
+	{#key items}
+		<option>Keyed</option>
+	{/key}
+</select>
+
+<!-- select with snippet defined at top level and rendered - should NOT use customizable_select_element -->
+{#snippet opt()}
+	<option>Snippet</option>
+{/snippet}
+<select>
+	{@render opt()}
+</select>
+
+<!-- select with const inside each (should be ignored) - should NOT use customizable_select_element -->
+<select>
+	{#each items as item}
+		{@const x = item * 2}
+		<option>{x}</option>
+	{/each}
+</select>
+
+<!-- optgroup with rich option - SHOULD use customizable_select_element -->
+<select>
+	<optgroup label="Group">
+		<option><strong>Bold</strong></option>
+	</optgroup>
+</select>
+
+<!-- optgroup with each containing plain options - should NOT use customizable_select_element -->
+<select>
+	<optgroup label="Group">
+		{#each items as item}
+			<option>{item}</option>
+		{/each}
+	</optgroup>
+</select>
+
+<!-- option with rich content (span) - SHOULD use customizable_select_element -->
+<select>
+	<option value="a"><em>Italic</em> text</option>
+</select>
+
+<!-- nested: select > each > option with rich content - SHOULD use customizable_select_element on option -->
+<select>
+	{#each items as item}
+		<option><span>{item}</span></option>
+	{/each}
+</select>
+
+<!-- nested: select > if > each > plain options - should NOT use customizable_select_element -->
+<select>
+	{#if show}
+		{#each items as item}
+			<option>{item}</option>
+		{/each}
+	{/if}
+</select>
+
+<!-- select with svelte:boundary containing plain options - should NOT use customizable_select_element -->
+<select>
+	<svelte:boundary>
+		<option>Boundary</option>
+	</svelte:boundary>
+</select>
+
+<!-- select with svelte:boundary containing rich options - SHOULD use customizable_select_element on option -->
+<select>
+	<svelte:boundary>
+		<option><span>Rich in boundary</span></option>
+	</svelte:boundary>
+</select>
+
+<!-- select with Component - SHOULD be treated as rich content -->
+<select>
+	<Option />
+</select>
+
+<!-- select with @render snippet - SHOULD be treated as rich content -->
+{#snippet option_snippet()}
+	<option>Rendered</option>
+{/snippet}
+<select>
+	{@render option_snippet()}
+</select>
+
+<!-- select with @html - SHOULD be treated as rich content -->
+<select>
+	{@html html}
+</select>
+
+<!-- optgroup with Component - SHOULD be treated as rich content -->
+<select>
+	<optgroup label="Group">
+		<Option />
+	</optgroup>
+</select>
+
+<!-- optgroup with @render - SHOULD be treated as rich content -->
+{#snippet option_snippet2()}
+	<option>Rendered in group</option>
+{/snippet}
+<select>
+	<optgroup label="Group">
+		{@render option_snippet2()}
+	</optgroup>
+</select>
+
+<!-- option with @html inside - SHOULD use customizable_select_element -->
+<select>
+	<option>{@html '<strong>Bold HTML</strong>'}</option>
+</select>
+
+<!-- each block inside select with Component - SHOULD be treated as rich -->
+<select>
+	{#each items as item}
+		<Option />
+	{/each}
+</select>
+
+<!-- if block inside select with @render - SHOULD be treated as rich -->
+{#snippet conditional_option()}
+	<option>Conditional</option>
+{/snippet}
+<select>
+	{#if show}
+		{@render conditional_option()}
+	{/if}
+</select>
diff --git a/packages/svelte/tests/validator/samples/a11y-consider-explicit-label/input.svelte b/packages/svelte/tests/validator/samples/a11y-consider-explicit-label/input.svelte
index 463889dc4f..023ca920e9 100644
--- a/packages/svelte/tests/validator/samples/a11y-consider-explicit-label/input.svelte
+++ b/packages/svelte/tests/validator/samples/a11y-consider-explicit-label/input.svelte
@@ -14,3 +14,14 @@
 <button>Click me</button>
 <a href="/#">Link text</a>
 <a href="/#"><img src="./icon.svg" alt="Link text"></a>
+
+<select>
+	<!-- valid if button contains <selectedcontent> -->
+	<button>
+		<selectedcontent></selectedcontent>
+	</button>
+
+	<option>one</option>
+	<option>two</option>
+	<option>three</option>
+</select>

From 9cf60666eac77ab7dc5b092cbe59949e29696b4b Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Sun, 18 Jan 2026 17:01:58 -0500
Subject: [PATCH 043/142] Version Packages (#17480)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/chubby-dingos-laugh.md |  5 -----
 .changeset/curly-cats-make.md     |  5 -----
 .changeset/little-aliens-pick.md  |  5 -----
 packages/svelte/CHANGELOG.md      | 12 ++++++++++++
 packages/svelte/package.json      |  2 +-
 packages/svelte/src/version.js    |  2 +-
 6 files changed, 14 insertions(+), 17 deletions(-)
 delete mode 100644 .changeset/chubby-dingos-laugh.md
 delete mode 100644 .changeset/curly-cats-make.md
 delete mode 100644 .changeset/little-aliens-pick.md

diff --git a/.changeset/chubby-dingos-laugh.md b/.changeset/chubby-dingos-laugh.md
deleted file mode 100644
index cd7b990e50..0000000000
--- a/.changeset/chubby-dingos-laugh.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': minor
----
-
-feat: customizable `<select>` elements
diff --git a/.changeset/curly-cats-make.md b/.changeset/curly-cats-make.md
deleted file mode 100644
index 393f8ec7e8..0000000000
--- a/.changeset/curly-cats-make.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: mark subtree of svelte boundary as dynamic
diff --git a/.changeset/little-aliens-pick.md b/.changeset/little-aliens-pick.md
deleted file mode 100644
index 1433625551..0000000000
--- a/.changeset/little-aliens-pick.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: don't reset static elements with debug/snippets
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index a767760641..e222997351 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,17 @@
 # svelte
 
+## 5.47.0
+
+### Minor Changes
+
+- feat: customizable `<select>` elements ([#17429](https://github.com/sveltejs/svelte/pull/17429))
+
+### Patch Changes
+
+- fix: mark subtree of svelte boundary as dynamic ([#17468](https://github.com/sveltejs/svelte/pull/17468))
+
+- fix: don't reset static elements with debug/snippets ([#17477](https://github.com/sveltejs/svelte/pull/17477))
+
 ## 5.46.4
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 1723e3d00a..19e37aaa93 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": "5.46.4",
+  "version": "5.47.0",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 96c48a055c..38b2a77f4a 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 = '5.46.4';
+export const VERSION = '5.47.0';
 export const PUBLIC_VERSION = '5';

From 4ea7631bf583c8db67c10c2b04a4002eabe5747e Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Mon, 19 Jan 2026 19:15:47 +0100
Subject: [PATCH 044/142] fix: trigger selectedcontent reactivity (#17486)

* fix: trigger `selectedcontent` reactivity

* fix: comments

* fix: use `is_supported`

* fix: use `cloneNode` to preserve attributes

* fix: update `selectedcontent` variable after cloning

* Apply suggestions from code review

* Apply suggestions from code review

* remove unused code

* do everything in a single for-of loop

* early return

* shorten

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/social-foxes-pull.md               |  5 ++
 .../2-analyze/visitors/RegularElement.js      |  2 +-
 .../client/visitors/RegularElement.js         | 12 +++++
 .../dom/elements/customizable-select.js       | 47 +++++++++++++++++++
 packages/svelte/src/internal/client/index.js  |  2 +-
 5 files changed, 66 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/social-foxes-pull.md

diff --git a/.changeset/social-foxes-pull.md b/.changeset/social-foxes-pull.md
new file mode 100644
index 0000000000..d164d43f7b
--- /dev/null
+++ b/.changeset/social-foxes-pull.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: trigger `selectedcontent` reactivity
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/RegularElement.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/RegularElement.js
index 1f3a93c67e..c7b40109a3 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/RegularElement.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/RegularElement.js
@@ -80,7 +80,7 @@ export function RegularElement(node, context) {
 
 	// Special case: <select>, <option> or <optgroup> with rich content needs special hydration handling
 	// We mark the subtree as dynamic so parent elements properly include the child init code
-	if (is_customizable_select_element(node)) {
+	if (is_customizable_select_element(node) || node.name === 'selectedcontent') {
 		// Mark the element's own fragment as dynamic so it's not treated as static
 		node.fragment.metadata.dynamic = true;
 		// Also mark ancestor fragments so parents properly include the child init code
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 3b3cf4c325..1faf44b902 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
@@ -457,6 +457,18 @@ export function RegularElement(node, context) {
 		context.state.after_update.push(...element_state.after_update);
 	}
 
+	if (node.name === 'selectedcontent') {
+		context.state.init.push(
+			b.stmt(
+				b.call(
+					'$.selectedcontent',
+					context.state.node,
+					b.arrow([b.id('$$element')], b.assignment('=', context.state.node, b.id('$$element')))
+				)
+			)
+		);
+	}
+
 	if (lookup.has('dir')) {
 		// This fixes an issue with Chromium where updates to text content within an element
 		// does not update the direction when set to auto. If we just re-assign the dir, this fixes it.
diff --git a/packages/svelte/src/internal/client/dom/elements/customizable-select.js b/packages/svelte/src/internal/client/dom/elements/customizable-select.js
index 5bf2144d1c..1858565d2a 100644
--- a/packages/svelte/src/internal/client/dom/elements/customizable-select.js
+++ b/packages/svelte/src/internal/client/dom/elements/customizable-select.js
@@ -1,5 +1,6 @@
 import { hydrating, reset, set_hydrate_node, set_hydrating } from '../hydration.js';
 import { create_comment } from '../operations.js';
+import { attach } from './attachments.js';
 
 /** @type {boolean | null} */
 let supported = null;
@@ -20,6 +21,52 @@ function is_supported() {
 	return supported;
 }
 
+/**
+ *
+ * @param {HTMLElement} element
+ * @param {(new_element: HTMLElement) => void} update_element
+ */
+export function selectedcontent(element, update_element) {
+	// if it's not supported no need for special logic
+	if (!is_supported()) return;
+
+	// we use the attach function directly just to make sure is executed when is mounted to the dom
+	attach(element, () => () => {
+		const select = element.closest('select');
+		if (!select) return;
+
+		const observer = new MutationObserver((entries) => {
+			var selected = false;
+
+			for (const entry of entries) {
+				if (entry.target === element) {
+					// the `<selectedcontent>` already changed, no need to replace it
+					return;
+				}
+
+				// if the changes doesn't include the selected `<option>` we don't need to do anything
+				selected ||= !!entry.target.parentElement?.closest('option')?.selected;
+			}
+
+			if (selected) {
+				// replace the `<selectedcontent>` with a clone
+				element.replaceWith((element = /** @type {HTMLElement} */ (element.cloneNode(true))));
+				update_element(element);
+			}
+		});
+
+		observer.observe(select, {
+			childList: true,
+			characterData: true,
+			subtree: true
+		});
+
+		return () => {
+			observer.disconnect();
+		};
+	});
+}
+
 /**
  * Handles rich HTML content inside `<option>`, `<optgroup>`, or `<select>` elements with browser-specific branching.
  * Modern browsers preserve HTML inside options, while older browsers strip it to text only.
diff --git a/packages/svelte/src/internal/client/index.js b/packages/svelte/src/internal/client/index.js
index 4792bc7230..0f20ce300d 100644
--- a/packages/svelte/src/internal/client/index.js
+++ b/packages/svelte/src/internal/client/index.js
@@ -42,7 +42,7 @@ export {
 export { set_class } from './dom/elements/class.js';
 export { apply, event, delegate, replay_events } from './dom/elements/events.js';
 export { autofocus, remove_textarea_child } from './dom/elements/misc.js';
-export { customizable_select } from './dom/elements/customizable-select.js';
+export { customizable_select, selectedcontent } from './dom/elements/customizable-select.js';
 export { set_style } from './dom/elements/style.js';
 export { animation, transition } from './dom/elements/transitions.js';
 export { bind_active_element } from './dom/elements/bindings/document.js';

From 16e9c70d1e97ef37800a67086b821e4bc77aa634 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Mon, 19 Jan 2026 20:47:01 +0100
Subject: [PATCH 045/142] Version Packages (#17488)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/social-foxes-pull.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/social-foxes-pull.md

diff --git a/.changeset/social-foxes-pull.md b/.changeset/social-foxes-pull.md
deleted file mode 100644
index d164d43f7b..0000000000
--- a/.changeset/social-foxes-pull.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: trigger `selectedcontent` reactivity
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index e222997351..d019b7883f 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,11 @@
 # svelte
 
+## 5.47.1
+
+### Patch Changes
+
+- fix: trigger `selectedcontent` reactivity ([#17486](https://github.com/sveltejs/svelte/pull/17486))
+
 ## 5.47.0
 
 ### Minor Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 19e37aaa93..38cac7b1cd 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": "5.47.0",
+  "version": "5.47.1",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 38b2a77f4a..a5360f7195 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 = '5.47.0';
+export const VERSION = '5.47.1';
 export const PUBLIC_VERSION = '5';

From 2eb54f57ae9b2411a40f10266133356ab647d907 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Mon, 19 Jan 2026 18:26:51 -0500
Subject: [PATCH 046/142] chore: tidy up benchmark code (#17490)

* add create_test utility

* add missing import

* DRY

* DRY out

* mol (this affects benchmark times, because create_test uses 1e3 iterations whereas the old code used 1e4)

* move utils.js

* WIP

* DRY

* reduce indirection

* more

* tidy up

* tidy up

* colocate

* DRY out
---
 benchmarking/benchmarks/reactivity/index.js   |  46 +-
 .../reactivity/kairo/kairo_avoidable.js       |  91 ----
 .../reactivity/kairo/kairo_broad.js           |  97 ----
 .../benchmarks/reactivity/kairo/kairo_deep.js |  97 ----
 .../reactivity/kairo/kairo_diamond.js         | 101 ----
 .../benchmarks/reactivity/kairo/kairo_mux.js  |  94 ----
 .../reactivity/kairo/kairo_repeated.js        |  98 ----
 .../reactivity/kairo/kairo_triangle.js        | 111 -----
 .../reactivity/kairo/kairo_unstable.js        |  97 ----
 .../benchmarks/reactivity/kairo/util.js       |   6 -
 benchmarking/benchmarks/reactivity/sbench.js  | 469 ++++++------------
 .../reactivity/tests/kairo_avoidable.bench.js |  35 ++
 .../reactivity/tests/kairo_broad.bench.js     |  41 ++
 .../reactivity/tests/kairo_deep.bench.js      |  41 ++
 .../reactivity/tests/kairo_diamond.bench.js   |  45 ++
 .../reactivity/tests/kairo_mux.bench.js       |  38 ++
 .../reactivity/tests/kairo_repeated.bench.js  |  42 ++
 .../reactivity/tests/kairo_triangle.bench.js  |  55 ++
 .../reactivity/tests/kairo_unstable.bench.js  |  41 ++
 .../{mol_bench.js => tests/mol.bench.js}      |  62 +--
 benchmarking/benchmarks/reactivity/util.js    |  73 +++
 21 files changed, 577 insertions(+), 1203 deletions(-)
 delete mode 100644 benchmarking/benchmarks/reactivity/kairo/kairo_avoidable.js
 delete mode 100644 benchmarking/benchmarks/reactivity/kairo/kairo_broad.js
 delete mode 100644 benchmarking/benchmarks/reactivity/kairo/kairo_deep.js
 delete mode 100644 benchmarking/benchmarks/reactivity/kairo/kairo_diamond.js
 delete mode 100644 benchmarking/benchmarks/reactivity/kairo/kairo_mux.js
 delete mode 100644 benchmarking/benchmarks/reactivity/kairo/kairo_repeated.js
 delete mode 100644 benchmarking/benchmarks/reactivity/kairo/kairo_triangle.js
 delete mode 100644 benchmarking/benchmarks/reactivity/kairo/kairo_unstable.js
 delete mode 100644 benchmarking/benchmarks/reactivity/kairo/util.js
 create mode 100644 benchmarking/benchmarks/reactivity/tests/kairo_avoidable.bench.js
 create mode 100644 benchmarking/benchmarks/reactivity/tests/kairo_broad.bench.js
 create mode 100644 benchmarking/benchmarks/reactivity/tests/kairo_deep.bench.js
 create mode 100644 benchmarking/benchmarks/reactivity/tests/kairo_diamond.bench.js
 create mode 100644 benchmarking/benchmarks/reactivity/tests/kairo_mux.bench.js
 create mode 100644 benchmarking/benchmarks/reactivity/tests/kairo_repeated.bench.js
 create mode 100644 benchmarking/benchmarks/reactivity/tests/kairo_triangle.bench.js
 create mode 100644 benchmarking/benchmarks/reactivity/tests/kairo_unstable.bench.js
 rename benchmarking/benchmarks/reactivity/{mol_bench.js => tests/mol.bench.js} (56%)
 create mode 100644 benchmarking/benchmarks/reactivity/util.js

diff --git a/benchmarking/benchmarks/reactivity/index.js b/benchmarking/benchmarks/reactivity/index.js
index 58b3f5cb29..2b75b3dfc6 100644
--- a/benchmarking/benchmarks/reactivity/index.js
+++ b/benchmarking/benchmarks/reactivity/index.js
@@ -1,12 +1,5 @@
-import { kairo_avoidable_owned, kairo_avoidable_unowned } from './kairo/kairo_avoidable.js';
-import { kairo_broad_owned, kairo_broad_unowned } from './kairo/kairo_broad.js';
-import { kairo_deep_owned, kairo_deep_unowned } from './kairo/kairo_deep.js';
-import { kairo_diamond_owned, kairo_diamond_unowned } from './kairo/kairo_diamond.js';
-import { kairo_mux_unowned, kairo_mux_owned } from './kairo/kairo_mux.js';
-import { kairo_repeated_unowned, kairo_repeated_owned } from './kairo/kairo_repeated.js';
-import { kairo_triangle_owned, kairo_triangle_unowned } from './kairo/kairo_triangle.js';
-import { kairo_unstable_owned, kairo_unstable_unowned } from './kairo/kairo_unstable.js';
-import { mol_bench_owned, mol_bench_unowned } from './mol_bench.js';
+import fs from 'node:fs';
+import path from 'node:path';
 import {
 	sbench_create_0to1,
 	sbench_create_1000to1,
@@ -19,10 +12,14 @@ import {
 	sbench_create_4to1,
 	sbench_create_signals
 } from './sbench.js';
+import { fileURLToPath } from 'node:url';
+import { create_test } from './util.js';
 
 // This benchmark has been adapted from the js-reactivity-benchmark (https://github.com/milomg/js-reactivity-benchmark)
 // Not all tests are the same, and many parts have been tweaked to capture different data.
 
+const dirname = path.dirname(fileURLToPath(import.meta.url));
+
 export const reactivity_benchmarks = [
 	sbench_create_signals,
 	sbench_create_0to1,
@@ -33,23 +30,16 @@ export const reactivity_benchmarks = [
 	sbench_create_1to2,
 	sbench_create_1to4,
 	sbench_create_1to8,
-	sbench_create_1to1000,
-	kairo_avoidable_owned,
-	kairo_avoidable_unowned,
-	kairo_broad_owned,
-	kairo_broad_unowned,
-	kairo_deep_owned,
-	kairo_deep_unowned,
-	kairo_diamond_owned,
-	kairo_diamond_unowned,
-	kairo_triangle_owned,
-	kairo_triangle_unowned,
-	kairo_mux_owned,
-	kairo_mux_unowned,
-	kairo_repeated_owned,
-	kairo_repeated_unowned,
-	kairo_unstable_owned,
-	kairo_unstable_unowned,
-	mol_bench_owned,
-	mol_bench_unowned
+	sbench_create_1to1000
 ];
+
+for (const file of fs.readdirSync(`${dirname}/tests`)) {
+	if (!file.includes('.bench.')) continue;
+
+	const name = file.replace('.bench.js', '');
+
+	const module = await import(`${dirname}/tests/${file}`);
+	const { owned, unowned } = create_test(name, module.default);
+
+	reactivity_benchmarks.push(owned, unowned);
+}
diff --git a/benchmarking/benchmarks/reactivity/kairo/kairo_avoidable.js b/benchmarking/benchmarks/reactivity/kairo/kairo_avoidable.js
deleted file mode 100644
index 9daea6de99..0000000000
--- a/benchmarking/benchmarks/reactivity/kairo/kairo_avoidable.js
+++ /dev/null
@@ -1,91 +0,0 @@
-import { assert, fastest_test } from '../../../utils.js';
-import * as $ from 'svelte/internal/client';
-import { busy } from './util.js';
-
-function setup() {
-	let head = $.state(0);
-	let computed1 = $.derived(() => $.get(head));
-	let computed2 = $.derived(() => ($.get(computed1), 0));
-	let computed3 = $.derived(() => (busy(), $.get(computed2) + 1)); // heavy computation
-	let computed4 = $.derived(() => $.get(computed3) + 2);
-	let computed5 = $.derived(() => $.get(computed4) + 3);
-
-	const destroy = $.effect_root(() => {
-		$.render_effect(() => {
-			$.get(computed5);
-			busy(); // heavy side effect
-		});
-	});
-
-	return {
-		destroy,
-		run() {
-			$.flush(() => {
-				$.set(head, 1);
-			});
-			assert($.get(computed5) === 6);
-			for (let i = 0; i < 1000; i++) {
-				$.flush(() => {
-					$.set(head, i);
-				});
-				assert($.get(computed5) === 6);
-			}
-		}
-	};
-}
-
-export async function kairo_avoidable_unowned() {
-	// Do 10 loops to warm up JIT
-	for (let i = 0; i < 10; i++) {
-		const { run, destroy } = setup();
-		run();
-		destroy();
-	}
-
-	const { run, destroy } = setup();
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1000; i++) {
-			run();
-		}
-	});
-
-	destroy();
-
-	return {
-		benchmark: 'kairo_avoidable_unowned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function kairo_avoidable_owned() {
-	let run, destroy;
-
-	const destroy_owned = $.effect_root(() => {
-		// Do 10 loops to warm up JIT
-		for (let i = 0; i < 10; i++) {
-			const { run, destroy } = setup();
-			run();
-			destroy();
-		}
-
-		({ run, destroy } = setup());
-	});
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1000; i++) {
-			run();
-		}
-	});
-
-	// @ts-ignore
-	destroy();
-	destroy_owned();
-
-	return {
-		benchmark: 'kairo_avoidable_owned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
diff --git a/benchmarking/benchmarks/reactivity/kairo/kairo_broad.js b/benchmarking/benchmarks/reactivity/kairo/kairo_broad.js
deleted file mode 100644
index 8dc5710c87..0000000000
--- a/benchmarking/benchmarks/reactivity/kairo/kairo_broad.js
+++ /dev/null
@@ -1,97 +0,0 @@
-import { assert, fastest_test } from '../../../utils.js';
-import * as $ from 'svelte/internal/client';
-
-function setup() {
-	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;
-			});
-			$.render_effect(() => {
-				$.get(current2);
-				counter++;
-			});
-			last = current2;
-		}
-	});
-
-	return {
-		destroy,
-		run() {
-			$.flush(() => {
-				$.set(head, 1);
-			});
-			counter = 0;
-			for (let i = 0; i < 50; i++) {
-				$.flush(() => {
-					$.set(head, i);
-				});
-				assert($.get(last) === i + 50);
-			}
-			assert(counter === 50 * 50);
-		}
-	};
-}
-
-export async function kairo_broad_unowned() {
-	// Do 10 loops to warm up JIT
-	for (let i = 0; i < 10; i++) {
-		const { run, destroy } = setup();
-		run();
-		destroy();
-	}
-
-	const { run, destroy } = setup();
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1000; i++) {
-			run();
-		}
-	});
-
-	destroy();
-
-	return {
-		benchmark: 'kairo_broad_unowned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function kairo_broad_owned() {
-	let run, destroy;
-
-	const destroy_owned = $.effect_root(() => {
-		// Do 10 loops to warm up JIT
-		for (let i = 0; i < 10; i++) {
-			const { run, destroy } = setup();
-			run();
-			destroy();
-		}
-
-		({ run, destroy } = setup());
-	});
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1000; i++) {
-			run();
-		}
-	});
-
-	// @ts-ignore
-	destroy();
-	destroy_owned();
-
-	return {
-		benchmark: 'kairo_broad_owned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
diff --git a/benchmarking/benchmarks/reactivity/kairo/kairo_deep.js b/benchmarking/benchmarks/reactivity/kairo/kairo_deep.js
deleted file mode 100644
index 8690c85f86..0000000000
--- a/benchmarking/benchmarks/reactivity/kairo/kairo_deep.js
+++ /dev/null
@@ -1,97 +0,0 @@
-import { assert, fastest_test } from '../../../utils.js';
-import * as $ from 'svelte/internal/client';
-
-let len = 50;
-const iter = 50;
-
-function setup() {
-	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(() => {
-		$.render_effect(() => {
-			$.get(current);
-			counter++;
-		});
-	});
-
-	return {
-		destroy,
-		run() {
-			$.flush(() => {
-				$.set(head, 1);
-			});
-			counter = 0;
-			for (let i = 0; i < iter; i++) {
-				$.flush(() => {
-					$.set(head, i);
-				});
-				assert($.get(current) === len + i);
-			}
-			assert(counter === iter);
-		}
-	};
-}
-
-export async function kairo_deep_unowned() {
-	// Do 10 loops to warm up JIT
-	for (let i = 0; i < 10; i++) {
-		const { run, destroy } = setup();
-		run();
-		destroy();
-	}
-
-	const { run, destroy } = setup();
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1000; i++) {
-			run();
-		}
-	});
-
-	destroy();
-
-	return {
-		benchmark: 'kairo_deep_unowned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function kairo_deep_owned() {
-	let run, destroy;
-
-	const destroy_owned = $.effect_root(() => {
-		// Do 10 loops to warm up JIT
-		for (let i = 0; i < 10; i++) {
-			const { run, destroy } = setup();
-			run();
-			destroy();
-		}
-
-		({ run, destroy } = setup());
-	});
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1000; i++) {
-			run();
-		}
-	});
-
-	// @ts-ignore
-	destroy();
-	destroy_owned();
-
-	return {
-		benchmark: 'kairo_deep_owned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
diff --git a/benchmarking/benchmarks/reactivity/kairo/kairo_diamond.js b/benchmarking/benchmarks/reactivity/kairo/kairo_diamond.js
deleted file mode 100644
index bf4e07ee89..0000000000
--- a/benchmarking/benchmarks/reactivity/kairo/kairo_diamond.js
+++ /dev/null
@@ -1,101 +0,0 @@
-import { assert, fastest_test } from '../../../utils.js';
-import * as $ from 'svelte/internal/client';
-
-let width = 5;
-
-function setup() {
-	let head = $.state(0);
-	let current = [];
-	for (let i = 0; i < width; i++) {
-		current.push(
-			$.derived(() => {
-				return $.get(head) + 1;
-			})
-		);
-	}
-	let sum = $.derived(() => {
-		return current.map((x) => $.get(x)).reduce((a, b) => a + b, 0);
-	});
-	let counter = 0;
-
-	const destroy = $.effect_root(() => {
-		$.render_effect(() => {
-			$.get(sum);
-			counter++;
-		});
-	});
-
-	return {
-		destroy,
-		run() {
-			$.flush(() => {
-				$.set(head, 1);
-			});
-			assert($.get(sum) === 2 * width);
-			counter = 0;
-			for (let i = 0; i < 500; i++) {
-				$.flush(() => {
-					$.set(head, i);
-				});
-				assert($.get(sum) === (i + 1) * width);
-			}
-			assert(counter === 500);
-		}
-	};
-}
-
-export async function kairo_diamond_unowned() {
-	// Do 10 loops to warm up JIT
-	for (let i = 0; i < 10; i++) {
-		const { run, destroy } = setup();
-		run();
-		destroy();
-	}
-
-	const { run, destroy } = setup();
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1000; i++) {
-			run();
-		}
-	});
-
-	destroy();
-
-	return {
-		benchmark: 'kairo_diamond_unowned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function kairo_diamond_owned() {
-	let run, destroy;
-
-	const destroy_owned = $.effect_root(() => {
-		// Do 10 loops to warm up JIT
-		for (let i = 0; i < 10; i++) {
-			const { run, destroy } = setup();
-			run();
-			destroy();
-		}
-
-		({ run, destroy } = setup());
-	});
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1000; i++) {
-			run();
-		}
-	});
-
-	// @ts-ignore
-	destroy();
-	destroy_owned();
-
-	return {
-		benchmark: 'kairo_diamond_owned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
diff --git a/benchmarking/benchmarks/reactivity/kairo/kairo_mux.js b/benchmarking/benchmarks/reactivity/kairo/kairo_mux.js
deleted file mode 100644
index fc252a27b5..0000000000
--- a/benchmarking/benchmarks/reactivity/kairo/kairo_mux.js
+++ /dev/null
@@ -1,94 +0,0 @@
-import { assert, fastest_test } from '../../../utils.js';
-import * as $ from 'svelte/internal/client';
-
-function setup() {
-	let heads = new Array(100).fill(null).map((_) => $.state(0));
-	const mux = $.derived(() => {
-		return Object.fromEntries(heads.map((h) => $.get(h)).entries());
-	});
-	const splited = heads
-		.map((_, index) => $.derived(() => $.get(mux)[index]))
-		.map((x) => $.derived(() => $.get(x) + 1));
-
-	const destroy = $.effect_root(() => {
-		splited.forEach((x) => {
-			$.render_effect(() => {
-				$.get(x);
-			});
-		});
-	});
-
-	return {
-		destroy,
-		run() {
-			for (let i = 0; i < 10; i++) {
-				$.flush(() => {
-					$.set(heads[i], i);
-				});
-				assert($.get(splited[i]) === i + 1);
-			}
-			for (let i = 0; i < 10; i++) {
-				$.flush(() => {
-					$.set(heads[i], i * 2);
-				});
-				assert($.get(splited[i]) === i * 2 + 1);
-			}
-		}
-	};
-}
-
-export async function kairo_mux_unowned() {
-	// Do 10 loops to warm up JIT
-	for (let i = 0; i < 10; i++) {
-		const { run, destroy } = setup();
-		run();
-		destroy();
-	}
-
-	const { run, destroy } = setup();
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1000; i++) {
-			run();
-		}
-	});
-
-	destroy();
-
-	return {
-		benchmark: 'kairo_mux_unowned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function kairo_mux_owned() {
-	let run, destroy;
-
-	const destroy_owned = $.effect_root(() => {
-		// Do 10 loops to warm up JIT
-		for (let i = 0; i < 10; i++) {
-			const { run, destroy } = setup();
-			run();
-			destroy();
-		}
-
-		({ run, destroy } = setup());
-	});
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1000; i++) {
-			run();
-		}
-	});
-
-	// @ts-ignore
-	destroy();
-	destroy_owned();
-
-	return {
-		benchmark: 'kairo_mux_owned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
diff --git a/benchmarking/benchmarks/reactivity/kairo/kairo_repeated.js b/benchmarking/benchmarks/reactivity/kairo/kairo_repeated.js
deleted file mode 100644
index 3bee06ca0e..0000000000
--- a/benchmarking/benchmarks/reactivity/kairo/kairo_repeated.js
+++ /dev/null
@@ -1,98 +0,0 @@
-import { assert, fastest_test } from '../../../utils.js';
-import * as $ from 'svelte/internal/client';
-
-let size = 30;
-
-function setup() {
-	let head = $.state(0);
-	let current = $.derived(() => {
-		let result = 0;
-		for (let i = 0; i < size; i++) {
-			result += $.get(head);
-		}
-		return result;
-	});
-
-	let counter = 0;
-
-	const destroy = $.effect_root(() => {
-		$.render_effect(() => {
-			$.get(current);
-			counter++;
-		});
-	});
-
-	return {
-		destroy,
-		run() {
-			$.flush(() => {
-				$.set(head, 1);
-			});
-			assert($.get(current) === size);
-			counter = 0;
-			for (let i = 0; i < 100; i++) {
-				$.flush(() => {
-					$.set(head, i);
-				});
-				assert($.get(current) === i * size);
-			}
-			assert(counter === 100);
-		}
-	};
-}
-
-export async function kairo_repeated_unowned() {
-	// Do 10 loops to warm up JIT
-	for (let i = 0; i < 10; i++) {
-		const { run, destroy } = setup();
-		run();
-		destroy();
-	}
-
-	const { run, destroy } = setup();
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1000; i++) {
-			run();
-		}
-	});
-
-	destroy();
-
-	return {
-		benchmark: 'kairo_repeated_unowned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function kairo_repeated_owned() {
-	let run, destroy;
-
-	const destroy_owned = $.effect_root(() => {
-		// Do 10 loops to warm up JIT
-		for (let i = 0; i < 10; i++) {
-			const { run, destroy } = setup();
-			run();
-			destroy();
-		}
-
-		({ run, destroy } = setup());
-	});
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1000; i++) {
-			run();
-		}
-	});
-
-	// @ts-ignore
-	destroy();
-	destroy_owned();
-
-	return {
-		benchmark: 'kairo_repeated_owned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
diff --git a/benchmarking/benchmarks/reactivity/kairo/kairo_triangle.js b/benchmarking/benchmarks/reactivity/kairo/kairo_triangle.js
deleted file mode 100644
index 11a419a52e..0000000000
--- a/benchmarking/benchmarks/reactivity/kairo/kairo_triangle.js
+++ /dev/null
@@ -1,111 +0,0 @@
-import { assert, fastest_test } from '../../../utils.js';
-import * as $ from 'svelte/internal/client';
-
-let width = 10;
-
-function count(number) {
-	return new Array(number)
-		.fill(0)
-		.map((_, i) => i + 1)
-		.reduce((x, y) => x + y, 0);
-}
-
-function setup() {
-	let head = $.state(0);
-	let current = head;
-	let list = [];
-	for (let i = 0; i < width; i++) {
-		let c = current;
-		list.push(current);
-		current = $.derived(() => {
-			return $.get(c) + 1;
-		});
-	}
-	let sum = $.derived(() => {
-		return list.map((x) => $.get(x)).reduce((a, b) => a + b, 0);
-	});
-
-	let counter = 0;
-
-	const destroy = $.effect_root(() => {
-		$.render_effect(() => {
-			$.get(sum);
-			counter++;
-		});
-	});
-
-	return {
-		destroy,
-		run() {
-			const constant = count(width);
-			$.flush(() => {
-				$.set(head, 1);
-			});
-			assert($.get(sum) === constant);
-			counter = 0;
-			for (let i = 0; i < 100; i++) {
-				$.flush(() => {
-					$.set(head, i);
-				});
-				assert($.get(sum) === constant - width + i * width);
-			}
-			assert(counter === 100);
-		}
-	};
-}
-
-export async function kairo_triangle_unowned() {
-	// Do 10 loops to warm up JIT
-	for (let i = 0; i < 10; i++) {
-		const { run, destroy } = setup();
-		run();
-		destroy();
-	}
-
-	const { run, destroy } = setup();
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1000; i++) {
-			run();
-		}
-	});
-
-	destroy();
-
-	return {
-		benchmark: 'kairo_triangle_unowned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function kairo_triangle_owned() {
-	let run, destroy;
-
-	const destroy_owned = $.effect_root(() => {
-		// Do 10 loops to warm up JIT
-		for (let i = 0; i < 10; i++) {
-			const { run, destroy } = setup();
-			run();
-			destroy();
-		}
-
-		({ run, destroy } = setup());
-	});
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1000; i++) {
-			run();
-		}
-	});
-
-	// @ts-ignore
-	destroy();
-	destroy_owned();
-
-	return {
-		benchmark: 'kairo_triangle_owned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
diff --git a/benchmarking/benchmarks/reactivity/kairo/kairo_unstable.js b/benchmarking/benchmarks/reactivity/kairo/kairo_unstable.js
deleted file mode 100644
index 54eb732cb2..0000000000
--- a/benchmarking/benchmarks/reactivity/kairo/kairo_unstable.js
+++ /dev/null
@@ -1,97 +0,0 @@
-import { assert, fastest_test } from '../../../utils.js';
-import * as $ from 'svelte/internal/client';
-
-function setup() {
-	let head = $.state(0);
-	const double = $.derived(() => $.get(head) * 2);
-	const inverse = $.derived(() => -$.get(head));
-	let current = $.derived(() => {
-		let result = 0;
-		for (let i = 0; i < 20; i++) {
-			result += $.get(head) % 2 ? $.get(double) : $.get(inverse);
-		}
-		return result;
-	});
-
-	let counter = 0;
-
-	const destroy = $.effect_root(() => {
-		$.render_effect(() => {
-			$.get(current);
-			counter++;
-		});
-	});
-
-	return {
-		destroy,
-		run() {
-			$.flush(() => {
-				$.set(head, 1);
-			});
-			assert($.get(current) === 40);
-			counter = 0;
-			for (let i = 0; i < 100; i++) {
-				$.flush(() => {
-					$.set(head, i);
-				});
-			}
-			assert(counter === 100);
-		}
-	};
-}
-
-export async function kairo_unstable_unowned() {
-	// Do 10 loops to warm up JIT
-	for (let i = 0; i < 10; i++) {
-		const { run, destroy } = setup();
-		run();
-		destroy();
-	}
-
-	const { run, destroy } = setup();
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1000; i++) {
-			run();
-		}
-	});
-
-	destroy();
-
-	return {
-		benchmark: 'kairo_unstable_unowned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function kairo_unstable_owned() {
-	let run, destroy;
-
-	const destroy_owned = $.effect_root(() => {
-		// Do 10 loops to warm up JIT
-		for (let i = 0; i < 10; i++) {
-			const { run, destroy } = setup();
-			run();
-			destroy();
-		}
-
-		({ run, destroy } = setup());
-	});
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1000; i++) {
-			run();
-		}
-	});
-
-	// @ts-ignore
-	destroy();
-	destroy_owned();
-
-	return {
-		benchmark: 'kairo_unstable_owned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
diff --git a/benchmarking/benchmarks/reactivity/kairo/util.js b/benchmarking/benchmarks/reactivity/kairo/util.js
deleted file mode 100644
index 75e3641ab9..0000000000
--- a/benchmarking/benchmarks/reactivity/kairo/util.js
+++ /dev/null
@@ -1,6 +0,0 @@
-export function busy() {
-	let a = 0;
-	for (let i = 0; i < 1_00; i++) {
-		a++;
-	}
-}
diff --git a/benchmarking/benchmarks/reactivity/sbench.js b/benchmarking/benchmarks/reactivity/sbench.js
index ddeaef2514..196c29dc8d 100644
--- a/benchmarking/benchmarks/reactivity/sbench.js
+++ b/benchmarking/benchmarks/reactivity/sbench.js
@@ -1,3 +1,4 @@
+/** @import { Source } from '../../../packages/svelte/src/internal/client/types.js' */
 import { fastest_test } from '../../utils.js';
 import * as $ from '../../../packages/svelte/src/internal/client/index.js';
 
@@ -7,360 +8,180 @@ const COUNT = 1e5;
  * @param {number} n
  * @param {any[]} sources
  */
-function create_data_signals(n, sources) {
+function create_sources(n, sources) {
 	for (let i = 0; i < n; i++) {
 		sources[i] = $.state(i);
 	}
+
 	return sources;
 }
 
 /**
- * @param {number} i
+ * @param {Source<number>} source
  */
-function create_computation_0(i) {
-	$.derived(() => i);
+function create_derived(source) {
+	$.derived(() => $.get(source));
 }
 
 /**
- * @param {any} s1
- */
-function create_computation_1(s1) {
-	$.derived(() => $.get(s1));
-}
-/**
- * @param {any} s1
- * @param {any} s2
+ *
+ * @param {string} label
+ * @param {(n: number, sources: Array<Source<number>>)} fn
+ * @param {number} count
+ * @param {number} num_sources
  */
-function create_computation_2(s1, s2) {
-	$.derived(() => $.get(s1) + $.get(s2));
-}
-
-function create_computation_1000(ss, offset) {
-	$.derived(() => {
-		let sum = 0;
-		for (let i = 0; i < 1000; i++) {
-			sum += $.get(ss[offset + i]);
+function create_sbench_test(label, count, num_sources, fn) {
+	return async () => {
+		// Do 3 loops to warm up JIT
+		for (let i = 0; i < 3; i++) {
+			fn(count, create_sources(num_sources, []));
 		}
-		return sum;
-	});
-}
 
-/**
- * @param {number} n
- */
-function create_computations_0to1(n) {
-	for (let i = 0; i < n; i++) {
-		create_computation_0(i);
-	}
-}
-
-/**
- * @param {number} n
- * @param {any[]} sources
- */
-function create_computations_1to1(n, sources) {
-	for (let i = 0; i < n; i++) {
-		const source = sources[i];
-		create_computation_1(source);
-	}
-}
+		const { timing } = await fastest_test(10, () => {
+			const destroy = $.effect_root(() => {
+				for (let i = 0; i < 10; i++) {
+					fn(count, create_sources(num_sources, []));
+				}
+			});
+			destroy();
+		});
 
-/**
- * @param {number} n
- * @param {any[]} sources
- */
-function create_computations_2to1(n, sources) {
-	for (let i = 0; i < n; i++) {
-		create_computation_2(sources[i * 2], sources[i * 2 + 1]);
-	}
+		return {
+			benchmark: label,
+			time: timing.time.toFixed(2),
+			gc_time: timing.gc_time.toFixed(2)
+		};
+	};
 }
 
-function create_computation_4(s1, s2, s3, s4) {
-	$.derived(() => $.get(s1) + $.get(s2) + $.get(s3) + $.get(s4));
-}
+export const sbench_create_signals = create_sbench_test(
+	'sbench_create_signals',
+	COUNT,
+	COUNT,
+	create_sources
+);
 
-function create_computations_1000to1(n, sources) {
+export const sbench_create_0to1 = create_sbench_test('sbench_create_0to1', COUNT, 0, (n) => {
 	for (let i = 0; i < n; i++) {
-		create_computation_1000(sources, i * 1000);
-	}
-}
-
-function create_computations_1to2(n, sources) {
-	for (let i = 0; i < n / 2; i++) {
-		const source = sources[i];
-		create_computation_1(source);
-		create_computation_1(source);
-	}
-}
-
-function create_computations_1to4(n, sources) {
-	for (let i = 0; i < n / 4; i++) {
-		const source = sources[i];
-		create_computation_1(source);
-		create_computation_1(source);
-		create_computation_1(source);
-		create_computation_1(source);
-	}
-}
-
-function create_computations_1to8(n, sources) {
-	for (let i = 0; i < n / 8; i++) {
-		const source = sources[i];
-		create_computation_1(source);
-		create_computation_1(source);
-		create_computation_1(source);
-		create_computation_1(source);
-		create_computation_1(source);
-		create_computation_1(source);
-		create_computation_1(source);
-		create_computation_1(source);
+		$.derived(() => i);
 	}
-}
+});
 
-function create_computations_1to1000(n, sources) {
-	for (let i = 0; i < n / 1000; i++) {
-		const source = sources[i];
-		for (let j = 0; j < 1000; j++) {
-			create_computation_1(source);
+export const sbench_create_1to1 = create_sbench_test(
+	'sbench_create_1to1',
+	COUNT,
+	COUNT,
+	(n, sources) => {
+		for (let i = 0; i < n; i++) {
+			create_derived(sources[i]);
 		}
 	}
-}
-
-function create_computations_4to1(n, sources) {
-	for (let i = 0; i < n; i++) {
-		create_computation_4(
-			sources[i * 4],
-			sources[i * 4 + 1],
-			sources[i * 4 + 2],
-			sources[i * 4 + 3]
-		);
-	}
-}
-
-/**
- * @param {any} fn
- * @param {number} count
- * @param {number} scount
- */
-function bench(fn, count, scount) {
-	let sources = create_data_signals(scount, []);
-
-	fn(count, sources);
-}
-
-export async function sbench_create_signals() {
-	// Do 3 loops to warm up JIT
-	for (let i = 0; i < 3; i++) {
-		bench(create_data_signals, COUNT, COUNT);
-	}
+);
 
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 100; i++) {
-			bench(create_data_signals, COUNT, COUNT);
+export const sbench_create_2to1 = create_sbench_test(
+	'sbench_create_2to1',
+	COUNT / 2,
+	COUNT,
+	(n, sources) => {
+		for (let i = 0; i < n; i++) {
+			$.derived(() => $.get(sources[i * 2]) + $.get(sources[i * 2 + 1]));
 		}
-	});
-
-	return {
-		benchmark: 'sbench_create_signals',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function sbench_create_0to1() {
-	// Do 3 loops to warm up JIT
-	for (let i = 0; i < 3; i++) {
-		bench(create_computations_0to1, COUNT, 0);
 	}
-
-	const { timing } = await fastest_test(10, () => {
-		const destroy = $.effect_root(() => {
-			for (let i = 0; i < 10; i++) {
-				bench(create_computations_0to1, COUNT, 0);
-			}
-		});
-		destroy();
-	});
-
-	return {
-		benchmark: 'sbench_create_0to1',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function sbench_create_1to1() {
-	// Do 3 loops to warm up JIT
-	for (let i = 0; i < 3; i++) {
-		bench(create_computations_1to1, COUNT, COUNT);
-	}
-
-	const { timing } = await fastest_test(10, () => {
-		const destroy = $.effect_root(() => {
-			for (let i = 0; i < 10; i++) {
-				bench(create_computations_1to1, COUNT, COUNT);
-			}
-		});
-		destroy();
-	});
-
-	return {
-		benchmark: 'sbench_create_1to1',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function sbench_create_2to1() {
-	// Do 3 loops to warm up JIT
-	for (let i = 0; i < 3; i++) {
-		bench(create_computations_2to1, COUNT / 2, COUNT);
-	}
-
-	const { timing } = await fastest_test(10, () => {
-		const destroy = $.effect_root(() => {
-			for (let i = 0; i < 10; i++) {
-				bench(create_computations_2to1, COUNT / 2, COUNT);
-			}
-		});
-		destroy();
-	});
-
-	return {
-		benchmark: 'sbench_create_2to1',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function sbench_create_4to1() {
-	// Do 3 loops to warm up JIT
-	for (let i = 0; i < 3; i++) {
-		bench(create_computations_4to1, COUNT / 4, COUNT);
+);
+
+export const sbench_create_4to1 = create_sbench_test(
+	'sbench_create_4to1',
+	COUNT / 4,
+	COUNT,
+	(n, sources) => {
+		for (let i = 0; i < n; i++) {
+			$.derived(
+				() =>
+					$.get(sources[i * 4]) +
+					$.get(sources[i * 4 + 1]) +
+					$.get(sources[i * 4 + 2]) +
+					$.get(sources[i * 4 + 3])
+			);
+		}
 	}
-
-	const { timing } = await fastest_test(10, () => {
-		const destroy = $.effect_root(() => {
-			for (let i = 0; i < 10; i++) {
-				bench(create_computations_4to1, COUNT / 4, COUNT);
-			}
-		});
-		destroy();
-	});
-
-	return {
-		benchmark: 'sbench_create_4to1',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function sbench_create_1000to1() {
-	// Do 3 loops to warm up JIT
-	for (let i = 0; i < 3; i++) {
-		bench(create_computations_1000to1, COUNT / 1000, COUNT);
+);
+
+export const sbench_create_1000to1 = create_sbench_test(
+	'sbench_create_1000to1',
+	COUNT / 1000,
+	COUNT,
+	(n, sources) => {
+		for (let i = 0; i < n; i++) {
+			const offset = i * 1000;
+
+			$.derived(() => {
+				let sum = 0;
+				for (let i = 0; i < 1000; i++) {
+					sum += $.get(sources[offset + i]);
+				}
+				return sum;
+			});
+		}
 	}
-
-	const { timing } = await fastest_test(10, () => {
-		const destroy = $.effect_root(() => {
-			for (let i = 0; i < 10; i++) {
-				bench(create_computations_1000to1, COUNT / 1000, COUNT);
-			}
-		});
-		destroy();
-	});
-
-	return {
-		benchmark: 'sbench_create_1000to1',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function sbench_create_1to2() {
-	// Do 3 loops to warm up JIT
-	for (let i = 0; i < 3; i++) {
-		bench(create_computations_1to2, COUNT, COUNT / 2);
+);
+
+export const sbench_create_1to2 = create_sbench_test(
+	'sbench_create_1to2',
+	COUNT,
+	COUNT / 2,
+	(n, sources) => {
+		for (let i = 0; i < n / 2; i++) {
+			const source = sources[i];
+			create_derived(source);
+			create_derived(source);
+		}
 	}
-
-	const { timing } = await fastest_test(10, () => {
-		const destroy = $.effect_root(() => {
-			for (let i = 0; i < 10; i++) {
-				bench(create_computations_1to2, COUNT, COUNT / 2);
-			}
-		});
-		destroy();
-	});
-
-	return {
-		benchmark: 'sbench_create_1to2',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function sbench_create_1to4() {
-	// Do 3 loops to warm up JIT
-	for (let i = 0; i < 3; i++) {
-		bench(create_computations_1to4, COUNT, COUNT / 4);
+);
+
+export const sbench_create_1to4 = create_sbench_test(
+	'sbench_create_1to4',
+	COUNT,
+	COUNT / 4,
+	(n, sources) => {
+		for (let i = 0; i < n / 4; i++) {
+			const source = sources[i];
+			create_derived(source);
+			create_derived(source);
+			create_derived(source);
+			create_derived(source);
+		}
 	}
-
-	const { timing } = await fastest_test(10, () => {
-		const destroy = $.effect_root(() => {
-			for (let i = 0; i < 10; i++) {
-				bench(create_computations_1to4, COUNT, COUNT / 4);
-			}
-		});
-		destroy();
-	});
-
-	return {
-		benchmark: 'sbench_create_1to4',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function sbench_create_1to8() {
-	// Do 3 loops to warm up JIT
-	for (let i = 0; i < 3; i++) {
-		bench(create_computations_1to8, COUNT, COUNT / 8);
+);
+
+export const sbench_create_1to8 = create_sbench_test(
+	'sbench_create_1to8',
+	COUNT,
+	COUNT / 8,
+	(n, sources) => {
+		for (let i = 0; i < n / 8; i++) {
+			const source = sources[i];
+			create_derived(source);
+			create_derived(source);
+			create_derived(source);
+			create_derived(source);
+			create_derived(source);
+			create_derived(source);
+			create_derived(source);
+			create_derived(source);
+		}
 	}
-
-	const { timing } = await fastest_test(10, () => {
-		const destroy = $.effect_root(() => {
-			for (let i = 0; i < 10; i++) {
-				bench(create_computations_1to8, COUNT, COUNT / 8);
+);
+
+export const sbench_create_1to1000 = create_sbench_test(
+	'sbench_create_1to1000',
+	COUNT,
+	COUNT / 1000,
+	(n, sources) => {
+		for (let i = 0; i < n / 1000; i++) {
+			const source = sources[i];
+			for (let j = 0; j < 1000; j++) {
+				create_derived(source);
 			}
-		});
-		destroy();
-	});
-
-	return {
-		benchmark: 'sbench_create_1to8',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function sbench_create_1to1000() {
-	// Do 3 loops to warm up JIT
-	for (let i = 0; i < 3; i++) {
-		bench(create_computations_1to1000, COUNT, COUNT / 1000);
+		}
 	}
-
-	const { timing } = await fastest_test(10, () => {
-		const destroy = $.effect_root(() => {
-			for (let i = 0; i < 10; i++) {
-				bench(create_computations_1to1000, COUNT, COUNT / 1000);
-			}
-		});
-		destroy();
-	});
-
-	return {
-		benchmark: 'sbench_create_1to1000',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
+);
diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_avoidable.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_avoidable.bench.js
new file mode 100644
index 0000000000..bb8c234f05
--- /dev/null
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_avoidable.bench.js
@@ -0,0 +1,35 @@
+import { assert } from '../../../utils.js';
+import * as $ from 'svelte/internal/client';
+import { busy } from '../util.js';
+
+export default () => {
+	let head = $.state(0);
+	let computed1 = $.derived(() => $.get(head));
+	let computed2 = $.derived(() => ($.get(computed1), 0));
+	let computed3 = $.derived(() => (busy(), $.get(computed2) + 1)); // heavy computation
+	let computed4 = $.derived(() => $.get(computed3) + 2);
+	let computed5 = $.derived(() => $.get(computed4) + 3);
+
+	const destroy = $.effect_root(() => {
+		$.render_effect(() => {
+			$.get(computed5);
+			busy(); // heavy side effect
+		});
+	});
+
+	return {
+		destroy,
+		run() {
+			$.flush(() => {
+				$.set(head, 1);
+			});
+			assert($.get(computed5) === 6);
+			for (let i = 0; i < 1000; i++) {
+				$.flush(() => {
+					$.set(head, i);
+				});
+				assert($.get(computed5) === 6);
+			}
+		}
+	};
+};
diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_broad.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_broad.bench.js
new file mode 100644
index 0000000000..14e855566b
--- /dev/null
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_broad.bench.js
@@ -0,0 +1,41 @@
+import { assert } from '../../../utils.js';
+import * as $ from 'svelte/internal/client';
+
+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;
+			});
+			$.render_effect(() => {
+				$.get(current2);
+				counter++;
+			});
+			last = current2;
+		}
+	});
+
+	return {
+		destroy,
+		run() {
+			$.flush(() => {
+				$.set(head, 1);
+			});
+			counter = 0;
+			for (let i = 0; i < 50; i++) {
+				$.flush(() => {
+					$.set(head, i);
+				});
+				assert($.get(last) === i + 50);
+			}
+			assert(counter === 50 * 50);
+		}
+	};
+};
diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_deep.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_deep.bench.js
new file mode 100644
index 0000000000..1051b0c1cf
--- /dev/null
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_deep.bench.js
@@ -0,0 +1,41 @@
+import { assert } from '../../../utils.js';
+import * as $ from 'svelte/internal/client';
+
+let len = 50;
+const iter = 50;
+
+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(() => {
+		$.render_effect(() => {
+			$.get(current);
+			counter++;
+		});
+	});
+
+	return {
+		destroy,
+		run() {
+			$.flush(() => {
+				$.set(head, 1);
+			});
+			counter = 0;
+			for (let i = 0; i < iter; i++) {
+				$.flush(() => {
+					$.set(head, i);
+				});
+				assert($.get(current) === len + i);
+			}
+			assert(counter === iter);
+		}
+	};
+};
diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_diamond.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_diamond.bench.js
new file mode 100644
index 0000000000..cde53fa3eb
--- /dev/null
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_diamond.bench.js
@@ -0,0 +1,45 @@
+import { assert } from '../../../utils.js';
+import * as $ from 'svelte/internal/client';
+
+let width = 5;
+
+export default () => {
+	let head = $.state(0);
+	let current = [];
+	for (let i = 0; i < width; i++) {
+		current.push(
+			$.derived(() => {
+				return $.get(head) + 1;
+			})
+		);
+	}
+	let sum = $.derived(() => {
+		return current.map((x) => $.get(x)).reduce((a, b) => a + b, 0);
+	});
+	let counter = 0;
+
+	const destroy = $.effect_root(() => {
+		$.render_effect(() => {
+			$.get(sum);
+			counter++;
+		});
+	});
+
+	return {
+		destroy,
+		run() {
+			$.flush(() => {
+				$.set(head, 1);
+			});
+			assert($.get(sum) === 2 * width);
+			counter = 0;
+			for (let i = 0; i < 500; i++) {
+				$.flush(() => {
+					$.set(head, i);
+				});
+				assert($.get(sum) === (i + 1) * width);
+			}
+			assert(counter === 500);
+		}
+	};
+};
diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_mux.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_mux.bench.js
new file mode 100644
index 0000000000..cfc7592c15
--- /dev/null
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_mux.bench.js
@@ -0,0 +1,38 @@
+import { assert } from '../../../utils.js';
+import * as $ from 'svelte/internal/client';
+
+export default () => {
+	let heads = new Array(100).fill(null).map((_) => $.state(0));
+	const mux = $.derived(() => {
+		return Object.fromEntries(heads.map((h) => $.get(h)).entries());
+	});
+	const splited = heads
+		.map((_, index) => $.derived(() => $.get(mux)[index]))
+		.map((x) => $.derived(() => $.get(x) + 1));
+
+	const destroy = $.effect_root(() => {
+		splited.forEach((x) => {
+			$.render_effect(() => {
+				$.get(x);
+			});
+		});
+	});
+
+	return {
+		destroy,
+		run() {
+			for (let i = 0; i < 10; i++) {
+				$.flush(() => {
+					$.set(heads[i], i);
+				});
+				assert($.get(splited[i]) === i + 1);
+			}
+			for (let i = 0; i < 10; i++) {
+				$.flush(() => {
+					$.set(heads[i], i * 2);
+				});
+				assert($.get(splited[i]) === i * 2 + 1);
+			}
+		}
+	};
+};
diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_repeated.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_repeated.bench.js
new file mode 100644
index 0000000000..2887a39931
--- /dev/null
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_repeated.bench.js
@@ -0,0 +1,42 @@
+import { assert } from '../../../utils.js';
+import * as $ from 'svelte/internal/client';
+
+let size = 30;
+
+export default () => {
+	let head = $.state(0);
+	let current = $.derived(() => {
+		let result = 0;
+		for (let i = 0; i < size; i++) {
+			result += $.get(head);
+		}
+		return result;
+	});
+
+	let counter = 0;
+
+	const destroy = $.effect_root(() => {
+		$.render_effect(() => {
+			$.get(current);
+			counter++;
+		});
+	});
+
+	return {
+		destroy,
+		run() {
+			$.flush(() => {
+				$.set(head, 1);
+			});
+			assert($.get(current) === size);
+			counter = 0;
+			for (let i = 0; i < 100; i++) {
+				$.flush(() => {
+					$.set(head, i);
+				});
+				assert($.get(current) === i * size);
+			}
+			assert(counter === 100);
+		}
+	};
+};
diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_triangle.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_triangle.bench.js
new file mode 100644
index 0000000000..0abdd1e13d
--- /dev/null
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_triangle.bench.js
@@ -0,0 +1,55 @@
+import { assert } from '../../../utils.js';
+import * as $ from 'svelte/internal/client';
+
+let width = 10;
+
+function count(number) {
+	return new Array(number)
+		.fill(0)
+		.map((_, i) => i + 1)
+		.reduce((x, y) => x + y, 0);
+}
+
+export default () => {
+	let head = $.state(0);
+	let current = head;
+	let list = [];
+	for (let i = 0; i < width; i++) {
+		let c = current;
+		list.push(current);
+		current = $.derived(() => {
+			return $.get(c) + 1;
+		});
+	}
+	let sum = $.derived(() => {
+		return list.map((x) => $.get(x)).reduce((a, b) => a + b, 0);
+	});
+
+	let counter = 0;
+
+	const destroy = $.effect_root(() => {
+		$.render_effect(() => {
+			$.get(sum);
+			counter++;
+		});
+	});
+
+	return {
+		destroy,
+		run() {
+			const constant = count(width);
+			$.flush(() => {
+				$.set(head, 1);
+			});
+			assert($.get(sum) === constant);
+			counter = 0;
+			for (let i = 0; i < 100; i++) {
+				$.flush(() => {
+					$.set(head, i);
+				});
+				assert($.get(sum) === constant - width + i * width);
+			}
+			assert(counter === 100);
+		}
+	};
+};
diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_unstable.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_unstable.bench.js
new file mode 100644
index 0000000000..b09467326f
--- /dev/null
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_unstable.bench.js
@@ -0,0 +1,41 @@
+import { assert } from '../../../utils.js';
+import * as $ from 'svelte/internal/client';
+
+export default () => {
+	let head = $.state(0);
+	const double = $.derived(() => $.get(head) * 2);
+	const inverse = $.derived(() => -$.get(head));
+	let current = $.derived(() => {
+		let result = 0;
+		for (let i = 0; i < 20; i++) {
+			result += $.get(head) % 2 ? $.get(double) : $.get(inverse);
+		}
+		return result;
+	});
+
+	let counter = 0;
+
+	const destroy = $.effect_root(() => {
+		$.render_effect(() => {
+			$.get(current);
+			counter++;
+		});
+	});
+
+	return {
+		destroy,
+		run() {
+			$.flush(() => {
+				$.set(head, 1);
+			});
+			assert($.get(current) === 40);
+			counter = 0;
+			for (let i = 0; i < 100; i++) {
+				$.flush(() => {
+					$.set(head, i);
+				});
+			}
+			assert(counter === 100);
+		}
+	};
+};
diff --git a/benchmarking/benchmarks/reactivity/mol_bench.js b/benchmarking/benchmarks/reactivity/tests/mol.bench.js
similarity index 56%
rename from benchmarking/benchmarks/reactivity/mol_bench.js
rename to benchmarking/benchmarks/reactivity/tests/mol.bench.js
index 536b078d74..56b6dc8b28 100644
--- a/benchmarking/benchmarks/reactivity/mol_bench.js
+++ b/benchmarking/benchmarks/reactivity/tests/mol.bench.js
@@ -1,4 +1,4 @@
-import { assert, fastest_test } from '../../utils.js';
+import { assert } from '../../../utils.js';
 import * as $ from 'svelte/internal/client';
 
 /**
@@ -18,7 +18,7 @@ function hard(n) {
 
 const numbers = Array.from({ length: 5 }, (_, i) => i);
 
-function setup() {
+export default () => {
 	let res = [];
 	const A = $.state(0);
 	const B = $.state(0);
@@ -62,60 +62,4 @@ function setup() {
 			assert(res[0] === 3198 && res[1] === 1601 && res[2] === 3195 && res[3] === 1598);
 		}
 	};
-}
-
-export async function mol_bench_owned() {
-	let run, destroy;
-
-	const destroy_owned = $.effect_root(() => {
-		// Do 10 loops to warm up JIT
-		for (let i = 0; i < 10; i++) {
-			const { run, destroy } = setup();
-			run(0);
-			destroy();
-		}
-
-		({ run, destroy } = setup());
-	});
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1e4; i++) {
-			run(i);
-		}
-	});
-
-	// @ts-ignore
-	destroy();
-	destroy_owned();
-
-	return {
-		benchmark: 'mol_bench_owned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
-
-export async function mol_bench_unowned() {
-	// Do 10 loops to warm up JIT
-	for (let i = 0; i < 10; i++) {
-		const { run, destroy } = setup();
-		run(0);
-		destroy();
-	}
-
-	const { run, destroy } = setup();
-
-	const { timing } = await fastest_test(10, () => {
-		for (let i = 0; i < 1e4; i++) {
-			run(i);
-		}
-	});
-
-	destroy();
-
-	return {
-		benchmark: 'mol_bench_unowned',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
-	};
-}
+};
diff --git a/benchmarking/benchmarks/reactivity/util.js b/benchmarking/benchmarks/reactivity/util.js
new file mode 100644
index 0000000000..18c4f556af
--- /dev/null
+++ b/benchmarking/benchmarks/reactivity/util.js
@@ -0,0 +1,73 @@
+import * as $ from 'svelte/internal/client';
+import { fastest_test } from '../../utils.js';
+
+export function busy() {
+	let a = 0;
+	for (let i = 0; i < 1_00; i++) {
+		a++;
+	}
+}
+
+/**
+ *
+ * @param {string} label
+ * @param {() => { run: (i?: number) => void, destroy: () => void }} setup
+ */
+export function create_test(label, setup) {
+	return {
+		unowned: async () => {
+			// Do 10 loops to warm up JIT
+			for (let i = 0; i < 10; i++) {
+				const { run, destroy } = setup();
+				run(0);
+				destroy();
+			}
+
+			const { run, destroy } = setup();
+
+			const { timing } = await fastest_test(10, () => {
+				for (let i = 0; i < 1000; i++) {
+					run(i);
+				}
+			});
+
+			destroy();
+
+			return {
+				benchmark: `${label}_unowned`,
+				time: timing.time.toFixed(2),
+				gc_time: timing.gc_time.toFixed(2)
+			};
+		},
+		owned: async () => {
+			let run, destroy;
+
+			const destroy_owned = $.effect_root(() => {
+				// Do 10 loops to warm up JIT
+				for (let i = 0; i < 10; i++) {
+					const { run, destroy } = setup();
+					run(0);
+					destroy();
+				}
+
+				({ run, destroy } = setup());
+			});
+
+			const { timing } = await fastest_test(10, () => {
+				for (let i = 0; i < 1000; i++) {
+					run(i);
+				}
+			});
+
+			// @ts-ignore
+			destroy();
+			destroy_owned();
+
+			return {
+				benchmark: `${label}_owned`,
+				time: timing.time.toFixed(2),
+				gc_time: timing.gc_time.toFixed(2)
+			};
+		}
+	};
+}

From 46c810ce71d14e165cab23fb5556e0ebfe3abf7d Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 21 Jan 2026 13:57:18 -0500
Subject: [PATCH 047/142] chore: tidy up the benchmarking code (#17504)

* chore: tidy up the benchmarking code

* use built-in assert

* fix find-replace fail
---
 benchmarking/benchmarks/reactivity/sbench.js  |   6 +-
 .../reactivity/tests/kairo_avoidable.bench.js |   6 +-
 .../reactivity/tests/kairo_broad.bench.js     |   6 +-
 .../reactivity/tests/kairo_deep.bench.js      |   6 +-
 .../reactivity/tests/kairo_diamond.bench.js   |   8 +-
 .../reactivity/tests/kairo_mux.bench.js       |   6 +-
 .../reactivity/tests/kairo_repeated.bench.js  |   8 +-
 .../reactivity/tests/kairo_triangle.bench.js  |   8 +-
 .../reactivity/tests/kairo_unstable.bench.js  |   6 +-
 .../benchmarks/reactivity/tests/mol.bench.js  |   7 +-
 benchmarking/benchmarks/reactivity/util.js    |  12 +-
 .../benchmarks/ssr/wrapper/wrapper_bench.js   |  33 ++++-
 benchmarking/utils.js                         | 114 +++---------------
 13 files changed, 88 insertions(+), 138 deletions(-)

diff --git a/benchmarking/benchmarks/reactivity/sbench.js b/benchmarking/benchmarks/reactivity/sbench.js
index 196c29dc8d..47ff4a621a 100644
--- a/benchmarking/benchmarks/reactivity/sbench.js
+++ b/benchmarking/benchmarks/reactivity/sbench.js
@@ -37,7 +37,7 @@ function create_sbench_test(label, count, num_sources, fn) {
 			fn(count, create_sources(num_sources, []));
 		}
 
-		const { timing } = await fastest_test(10, () => {
+		const { time, gc_time } = await fastest_test(10, () => {
 			const destroy = $.effect_root(() => {
 				for (let i = 0; i < 10; i++) {
 					fn(count, create_sources(num_sources, []));
@@ -48,8 +48,8 @@ function create_sbench_test(label, count, num_sources, fn) {
 
 		return {
 			benchmark: label,
-			time: timing.time.toFixed(2),
-			gc_time: timing.gc_time.toFixed(2)
+			time: time.toFixed(2),
+			gc_time: gc_time.toFixed(2)
 		};
 	};
 }
diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_avoidable.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_avoidable.bench.js
index bb8c234f05..d4ba858824 100644
--- a/benchmarking/benchmarks/reactivity/tests/kairo_avoidable.bench.js
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_avoidable.bench.js
@@ -1,4 +1,4 @@
-import { assert } from '../../../utils.js';
+import assert from 'node:assert';
 import * as $ from 'svelte/internal/client';
 import { busy } from '../util.js';
 
@@ -23,12 +23,12 @@ export default () => {
 			$.flush(() => {
 				$.set(head, 1);
 			});
-			assert($.get(computed5) === 6);
+			assert.equal($.get(computed5), 6);
 			for (let i = 0; i < 1000; i++) {
 				$.flush(() => {
 					$.set(head, i);
 				});
-				assert($.get(computed5) === 6);
+				assert.equal($.get(computed5), 6);
 			}
 		}
 	};
diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_broad.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_broad.bench.js
index 14e855566b..aebae7a898 100644
--- a/benchmarking/benchmarks/reactivity/tests/kairo_broad.bench.js
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_broad.bench.js
@@ -1,4 +1,4 @@
-import { assert } from '../../../utils.js';
+import assert from 'node:assert';
 import * as $ from 'svelte/internal/client';
 
 export default () => {
@@ -33,9 +33,9 @@ export default () => {
 				$.flush(() => {
 					$.set(head, i);
 				});
-				assert($.get(last) === i + 50);
+				assert.equal($.get(last), i + 50);
 			}
-			assert(counter === 50 * 50);
+			assert.equal(counter, 50 * 50);
 		}
 	};
 };
diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_deep.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_deep.bench.js
index 1051b0c1cf..4a361e9bfc 100644
--- a/benchmarking/benchmarks/reactivity/tests/kairo_deep.bench.js
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_deep.bench.js
@@ -1,4 +1,4 @@
-import { assert } from '../../../utils.js';
+import assert from 'node:assert';
 import * as $ from 'svelte/internal/client';
 
 let len = 50;
@@ -33,9 +33,9 @@ export default () => {
 				$.flush(() => {
 					$.set(head, i);
 				});
-				assert($.get(current) === len + i);
+				assert.equal($.get(current), len + i);
 			}
-			assert(counter === iter);
+			assert.equal(counter, iter);
 		}
 	};
 };
diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_diamond.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_diamond.bench.js
index cde53fa3eb..17d9bd85e5 100644
--- a/benchmarking/benchmarks/reactivity/tests/kairo_diamond.bench.js
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_diamond.bench.js
@@ -1,4 +1,4 @@
-import { assert } from '../../../utils.js';
+import assert from 'node:assert';
 import * as $ from 'svelte/internal/client';
 
 let width = 5;
@@ -31,15 +31,15 @@ export default () => {
 			$.flush(() => {
 				$.set(head, 1);
 			});
-			assert($.get(sum) === 2 * width);
+			assert.equal($.get(sum), 2 * width);
 			counter = 0;
 			for (let i = 0; i < 500; i++) {
 				$.flush(() => {
 					$.set(head, i);
 				});
-				assert($.get(sum) === (i + 1) * width);
+				assert.equal($.get(sum), (i + 1) * width);
 			}
-			assert(counter === 500);
+			assert.equal(counter, 500);
 		}
 	};
 };
diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_mux.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_mux.bench.js
index cfc7592c15..4af6bf7873 100644
--- a/benchmarking/benchmarks/reactivity/tests/kairo_mux.bench.js
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_mux.bench.js
@@ -1,4 +1,4 @@
-import { assert } from '../../../utils.js';
+import assert from 'node:assert';
 import * as $ from 'svelte/internal/client';
 
 export default () => {
@@ -25,13 +25,13 @@ export default () => {
 				$.flush(() => {
 					$.set(heads[i], i);
 				});
-				assert($.get(splited[i]) === i + 1);
+				assert.equal($.get(splited[i]), i + 1);
 			}
 			for (let i = 0; i < 10; i++) {
 				$.flush(() => {
 					$.set(heads[i], i * 2);
 				});
-				assert($.get(splited[i]) === i * 2 + 1);
+				assert.equal($.get(splited[i]), i * 2 + 1);
 			}
 		}
 	};
diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_repeated.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_repeated.bench.js
index 2887a39931..cab7689fea 100644
--- a/benchmarking/benchmarks/reactivity/tests/kairo_repeated.bench.js
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_repeated.bench.js
@@ -1,4 +1,4 @@
-import { assert } from '../../../utils.js';
+import assert from 'node:assert';
 import * as $ from 'svelte/internal/client';
 
 let size = 30;
@@ -28,15 +28,15 @@ export default () => {
 			$.flush(() => {
 				$.set(head, 1);
 			});
-			assert($.get(current) === size);
+			assert.equal($.get(current), size);
 			counter = 0;
 			for (let i = 0; i < 100; i++) {
 				$.flush(() => {
 					$.set(head, i);
 				});
-				assert($.get(current) === i * size);
+				assert.equal($.get(current), i * size);
 			}
-			assert(counter === 100);
+			assert.equal(counter, 100);
 		}
 	};
 };
diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_triangle.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_triangle.bench.js
index 0abdd1e13d..b4b46c0209 100644
--- a/benchmarking/benchmarks/reactivity/tests/kairo_triangle.bench.js
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_triangle.bench.js
@@ -1,4 +1,4 @@
-import { assert } from '../../../utils.js';
+import assert from 'node:assert';
 import * as $ from 'svelte/internal/client';
 
 let width = 10;
@@ -41,15 +41,15 @@ export default () => {
 			$.flush(() => {
 				$.set(head, 1);
 			});
-			assert($.get(sum) === constant);
+			assert.equal($.get(sum), constant);
 			counter = 0;
 			for (let i = 0; i < 100; i++) {
 				$.flush(() => {
 					$.set(head, i);
 				});
-				assert($.get(sum) === constant - width + i * width);
+				assert.equal($.get(sum), constant - width + i * width);
 			}
-			assert(counter === 100);
+			assert.equal(counter, 100);
 		}
 	};
 };
diff --git a/benchmarking/benchmarks/reactivity/tests/kairo_unstable.bench.js b/benchmarking/benchmarks/reactivity/tests/kairo_unstable.bench.js
index b09467326f..e7723fae0d 100644
--- a/benchmarking/benchmarks/reactivity/tests/kairo_unstable.bench.js
+++ b/benchmarking/benchmarks/reactivity/tests/kairo_unstable.bench.js
@@ -1,4 +1,4 @@
-import { assert } from '../../../utils.js';
+import assert from 'node:assert';
 import * as $ from 'svelte/internal/client';
 
 export default () => {
@@ -28,14 +28,14 @@ export default () => {
 			$.flush(() => {
 				$.set(head, 1);
 			});
-			assert($.get(current) === 40);
+			assert.equal($.get(current), 40);
 			counter = 0;
 			for (let i = 0; i < 100; i++) {
 				$.flush(() => {
 					$.set(head, i);
 				});
 			}
-			assert(counter === 100);
+			assert.equal(counter, 100);
 		}
 	};
 };
diff --git a/benchmarking/benchmarks/reactivity/tests/mol.bench.js b/benchmarking/benchmarks/reactivity/tests/mol.bench.js
index 56b6dc8b28..e66f0191d1 100644
--- a/benchmarking/benchmarks/reactivity/tests/mol.bench.js
+++ b/benchmarking/benchmarks/reactivity/tests/mol.bench.js
@@ -1,4 +1,4 @@
-import { assert } from '../../../utils.js';
+import assert from 'node:assert';
 import * as $ from 'svelte/internal/client';
 
 /**
@@ -59,7 +59,10 @@ export default () => {
 				$.set(A, 2 + i * 2);
 				$.set(B, 2);
 			});
-			assert(res[0] === 3198 && res[1] === 1601 && res[2] === 3195 && res[3] === 1598);
+			assert.equal(res[0], 3198);
+			assert.equal(res[1], 1601);
+			assert.equal(res[2], 3195);
+			assert.equal(res[3], 1598);
 		}
 	};
 };
diff --git a/benchmarking/benchmarks/reactivity/util.js b/benchmarking/benchmarks/reactivity/util.js
index 18c4f556af..ff0722d85e 100644
--- a/benchmarking/benchmarks/reactivity/util.js
+++ b/benchmarking/benchmarks/reactivity/util.js
@@ -25,7 +25,7 @@ export function create_test(label, setup) {
 
 			const { run, destroy } = setup();
 
-			const { timing } = await fastest_test(10, () => {
+			const { time, gc_time } = await fastest_test(10, () => {
 				for (let i = 0; i < 1000; i++) {
 					run(i);
 				}
@@ -35,8 +35,8 @@ export function create_test(label, setup) {
 
 			return {
 				benchmark: `${label}_unowned`,
-				time: timing.time.toFixed(2),
-				gc_time: timing.gc_time.toFixed(2)
+				time: time.toFixed(2),
+				gc_time: gc_time.toFixed(2)
 			};
 		},
 		owned: async () => {
@@ -53,7 +53,7 @@ export function create_test(label, setup) {
 				({ run, destroy } = setup());
 			});
 
-			const { timing } = await fastest_test(10, () => {
+			const { time, gc_time } = await fastest_test(10, () => {
 				for (let i = 0; i < 1000; i++) {
 					run(i);
 				}
@@ -65,8 +65,8 @@ export function create_test(label, setup) {
 
 			return {
 				benchmark: `${label}_owned`,
-				time: timing.time.toFixed(2),
-				gc_time: timing.gc_time.toFixed(2)
+				time: time.toFixed(2),
+				gc_time: gc_time.toFixed(2)
 			};
 		}
 	};
diff --git a/benchmarking/benchmarks/ssr/wrapper/wrapper_bench.js b/benchmarking/benchmarks/ssr/wrapper/wrapper_bench.js
index ba0457b80e..6fc992d4a2 100644
--- a/benchmarking/benchmarks/ssr/wrapper/wrapper_bench.js
+++ b/benchmarking/benchmarks/ssr/wrapper/wrapper_bench.js
@@ -1,13 +1,16 @@
+import * as fs from 'node:fs';
+import * as path from 'node:path';
 import { render } from 'svelte/server';
-import { fastest_test, read_file, write } from '../../../utils.js';
+import { fastest_test } from '../../../utils.js';
 import { compile } from 'svelte/compiler';
 
 const dir = `${process.cwd()}/benchmarking/benchmarks/ssr/wrapper`;
 
 async function compile_svelte() {
-	const output = compile(read_file(`${dir}/App.svelte`), {
+	const output = compile(read(`${dir}/App.svelte`), {
 		generate: 'server'
 	});
+
 	write(`${dir}/output/App.js`, output.js.code);
 
 	const module = await import(`${dir}/output/App.js`);
@@ -17,12 +20,13 @@ async function compile_svelte() {
 
 export async function wrapper_bench() {
 	const App = await compile_svelte();
+
 	// Do 3 loops to warm up JIT
 	for (let i = 0; i < 3; i++) {
 		render(App);
 	}
 
-	const { timing } = await fastest_test(10, () => {
+	const { time, gc_time } = await fastest_test(10, () => {
 		for (let i = 0; i < 100; i++) {
 			render(App);
 		}
@@ -30,7 +34,26 @@ export async function wrapper_bench() {
 
 	return {
 		benchmark: 'wrapper_bench',
-		time: timing.time.toFixed(2),
-		gc_time: timing.gc_time.toFixed(2)
+		time: time.toFixed(2),
+		gc_time: gc_time.toFixed(2)
 	};
 }
+
+/**
+ * @param {string} file
+ */
+function read(file) {
+	return fs.readFileSync(file, 'utf-8').replace(/\r\n/g, '\n');
+}
+
+/**
+ * @param {string} file
+ * @param {string} contents
+ */
+function write(file, contents) {
+	try {
+		fs.mkdirSync(path.dirname(file), { recursive: true });
+	} catch {}
+
+	fs.writeFileSync(file, contents);
+}
diff --git a/benchmarking/utils.js b/benchmarking/utils.js
index 684d2ee02b..5581135e00 100644
--- a/benchmarking/utils.js
+++ b/benchmarking/utils.js
@@ -1,78 +1,30 @@
 import { performance, PerformanceObserver } from 'node:perf_hooks';
 import v8 from 'v8-natives';
-import * as fs from 'node:fs';
-import * as path from 'node:path';
 
 // Credit to https://github.com/milomg/js-reactivity-benchmark for the logic for timing + GC tracking.
 
-class GarbageTrack {
-	track_id = 0;
-	observer = new PerformanceObserver((list) => this.perf_entries.push(...list.getEntries()));
-	perf_entries = [];
-	periods = [];
+async function track(fn) {
+	v8.collectGarbage();
 
-	watch(fn) {
-		this.track_id++;
-		const start = performance.now();
-		const result = fn();
-		const end = performance.now();
-		this.periods.push({ track_id: this.track_id, start, end });
+	/** @type {PerformanceEntry[]} */
+	const entries = [];
 
-		return { result, track_id: this.track_id };
-	}
+	const observer = new PerformanceObserver((list) => entries.push(...list.getEntries()));
+	observer.observe({ entryTypes: ['gc'] });
 
-	/**
-	 * @param {number} track_id
-	 */
-	async gcDuration(track_id) {
-		await promise_delay(10);
+	const start = performance.now();
+	fn();
+	const end = performance.now();
 
-		const period = this.periods.find((period) => period.track_id === track_id);
-		if (!period) {
-			// eslint-disable-next-line @typescript-eslint/prefer-promise-reject-errors
-			return Promise.reject('no period found');
-		}
+	await new Promise((f) => setTimeout(f, 10));
 
-		const entries = this.perf_entries.filter(
-			(e) => e.startTime >= period.start && e.startTime < period.end
-		);
-		return entries.reduce((t, e) => e.duration + t, 0);
-	}
+	const gc_time = entries
+		.filter((e) => e.startTime >= start && e.startTime < end)
+		.reduce((t, e) => e.duration + t, 0);
 
-	destroy() {
-		this.observer.disconnect();
-	}
+	observer.disconnect();
 
-	constructor() {
-		this.observer.observe({ entryTypes: ['gc'] });
-	}
-}
-
-function promise_delay(timeout = 0) {
-	return new Promise((resolve) => setTimeout(resolve, timeout));
-}
-
-/**
- * @param {{ (): void; (): any; }} fn
- */
-function run_timed(fn) {
-	const start = performance.now();
-	const result = fn();
-	const time = performance.now() - start;
-	return { result, time };
-}
-
-/**
- * @param {() => void} fn
- */
-async function run_tracked(fn) {
-	v8.collectGarbage();
-	const gc_track = new GarbageTrack();
-	const { result: wrappedResult, track_id } = gc_track.watch(() => run_timed(fn));
-	const gc_time = await gc_track.gcDuration(track_id);
-	const { result, time } = wrappedResult;
-	gc_track.destroy();
-	return { result, timing: { time, gc_time } };
+	return { time: end - start, gc_time };
 }
 
 /**
@@ -80,40 +32,12 @@ async function run_tracked(fn) {
  * @param {() => void} fn
  */
 export async function fastest_test(times, fn) {
+	/** @type {Array<{ time: number, gc_time: number }>} */
 	const results = [];
-	for (let i = 0; i < times; i++) {
-		const run = await run_tracked(fn);
-		results.push(run);
-	}
-	const fastest = results.reduce((a, b) => (a.timing.time < b.timing.time ? a : b));
 
-	return fastest;
-}
-
-/**
- * @param {boolean} a
- */
-export function assert(a) {
-	if (!a) {
-		throw new Error('Assertion failed');
+	for (let i = 0; i < times; i++) {
+		results.push(await track(fn));
 	}
-}
-
-/**
- * @param {string} file
- */
-export function read_file(file) {
-	return fs.readFileSync(file, 'utf-8').replace(/\r\n/g, '\n');
-}
-
-/**
- * @param {string} file
- * @param {string} contents
- */
-export function write(file, contents) {
-	try {
-		fs.mkdirSync(path.dirname(file), { recursive: true });
-	} catch {}
 
-	fs.writeFileSync(file, contents);
+	return results.reduce((a, b) => (a.time < b.time ? a : b));
 }

From c41fef1ef104f4797cca45051774d4a662156f9a Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 21 Jan 2026 14:45:07 -0500
Subject: [PATCH 048/142] Nicer bench output (#17505)

* test

* dont coerce to string

* more readable output for pnpm bench

* oops

* fix
---
 benchmarking/benchmarks/reactivity/sbench.js  |  4 +-
 benchmarking/benchmarks/reactivity/util.js    |  8 +--
 .../benchmarks/ssr/wrapper/wrapper_bench.js   |  4 +-
 benchmarking/run.js                           | 64 +++++++++++--------
 package.json                                  |  2 +-
 5 files changed, 48 insertions(+), 34 deletions(-)

diff --git a/benchmarking/benchmarks/reactivity/sbench.js b/benchmarking/benchmarks/reactivity/sbench.js
index 47ff4a621a..9c41f60746 100644
--- a/benchmarking/benchmarks/reactivity/sbench.js
+++ b/benchmarking/benchmarks/reactivity/sbench.js
@@ -48,8 +48,8 @@ function create_sbench_test(label, count, num_sources, fn) {
 
 		return {
 			benchmark: label,
-			time: time.toFixed(2),
-			gc_time: gc_time.toFixed(2)
+			time,
+			gc_time
 		};
 	};
 }
diff --git a/benchmarking/benchmarks/reactivity/util.js b/benchmarking/benchmarks/reactivity/util.js
index ff0722d85e..6a2e44f5ae 100644
--- a/benchmarking/benchmarks/reactivity/util.js
+++ b/benchmarking/benchmarks/reactivity/util.js
@@ -35,8 +35,8 @@ export function create_test(label, setup) {
 
 			return {
 				benchmark: `${label}_unowned`,
-				time: time.toFixed(2),
-				gc_time: gc_time.toFixed(2)
+				time,
+				gc_time
 			};
 		},
 		owned: async () => {
@@ -65,8 +65,8 @@ export function create_test(label, setup) {
 
 			return {
 				benchmark: `${label}_owned`,
-				time: time.toFixed(2),
-				gc_time: gc_time.toFixed(2)
+				time,
+				gc_time
 			};
 		}
 	};
diff --git a/benchmarking/benchmarks/ssr/wrapper/wrapper_bench.js b/benchmarking/benchmarks/ssr/wrapper/wrapper_bench.js
index 6fc992d4a2..6e790ee2b8 100644
--- a/benchmarking/benchmarks/ssr/wrapper/wrapper_bench.js
+++ b/benchmarking/benchmarks/ssr/wrapper/wrapper_bench.js
@@ -34,8 +34,8 @@ export async function wrapper_bench() {
 
 	return {
 		benchmark: 'wrapper_bench',
-		time: time.toFixed(2),
-		gc_time: gc_time.toFixed(2)
+		time,
+		gc_time
 	};
 }
 
diff --git a/benchmarking/run.js b/benchmarking/run.js
index bd96b9c2dc..f7b8128886 100644
--- a/benchmarking/run.js
+++ b/benchmarking/run.js
@@ -10,46 +10,60 @@ const suites = [
 	{ benchmarks: ssr_benchmarks, name: 'server-side rendering benchmarks' }
 ];
 
-// eslint-disable-next-line no-console
-console.log('\x1b[1m', '-- Benchmarking Started --', '\x1b[0m');
+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;
+
 $.push({}, true);
+
 try {
 	for (const { benchmarks, name } of suites) {
 		let suite_time = 0;
 		let suite_gc_time = 0;
-		// eslint-disable-next-line no-console
+
 		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 benchmark();
-			// eslint-disable-next-line no-console
-			console.log(results);
-			total_time += Number(results.time);
-			total_gc_time += Number(results.gc_time);
-			suite_time += Number(results.time);
-			suite_gc_time += Number(results.gc_time);
+			console.log(
+				pad_right(results.benchmark, 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(`\nFinished ${name}.\n`);
-
-		// eslint-disable-next-line no-console
-		console.log({
-			suite_time: suite_time.toFixed(2),
-			suite_gc_time: suite_gc_time.toFixed(2)
-		});
+		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));
 	}
 } catch (e) {
-	// eslint-disable-next-line no-console
-	console.log('\x1b[1m', '\n-- Benchmarking Failed --\n', '\x1b[0m');
 	// eslint-disable-next-line no-console
 	console.error(e);
 	process.exit(1);
 }
+
 $.pop();
-// eslint-disable-next-line no-console
-console.log('\x1b[1m', '\n-- Benchmarking Complete --\n', '\x1b[0m');
-// eslint-disable-next-line no-console
-console.log({
-	total_time: total_time.toFixed(2),
-	total_gc_time: total_gc_time.toFixed(2)
-});
+
+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])
+);
diff --git a/package.json b/package.json
index 12e59a2665..aa9c8cafa3 100644
--- a/package.json
+++ b/package.json
@@ -21,7 +21,7 @@
     "test": "vitest run",
     "changeset:version": "changeset version && pnpm -r generate:version && git add --all",
     "changeset:publish": "changeset publish",
-    "bench": "node --allow-natives-syntax ./benchmarking/run.js",
+    "bench": "NODE_ENV=production node --allow-natives-syntax ./benchmarking/run.js",
     "bench:compare": "node --allow-natives-syntax ./benchmarking/compare/index.js",
     "bench:debug": "node --allow-natives-syntax --inspect-brk ./benchmarking/run.js"
   },

From 0025d42366fa3652216cac8bf3adc1389ae49a3d Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 21 Jan 2026 15:53:37 -0500
Subject: [PATCH 049/142] chore: skippable benchmarks (#17506)

* chore: add benchmark filtering mechanism

* tweak

* fix

* try this

* better logging for bench:compare

* fix
---
 benchmarking/benchmarks/reactivity/sbench.js  | 35 ++++----
 benchmarking/benchmarks/reactivity/util.js    | 84 +++++++++----------
 .../benchmarks/ssr/wrapper/wrapper_bench.js   | 29 +++----
 benchmarking/compare/runner.js                | 11 ++-
 benchmarking/run.js                           | 32 +++++--
 package.json                                  |  4 +-
 6 files changed, 104 insertions(+), 91 deletions(-)

diff --git a/benchmarking/benchmarks/reactivity/sbench.js b/benchmarking/benchmarks/reactivity/sbench.js
index 9c41f60746..e197f970c8 100644
--- a/benchmarking/benchmarks/reactivity/sbench.js
+++ b/benchmarking/benchmarks/reactivity/sbench.js
@@ -26,31 +26,28 @@ function create_derived(source) {
 /**
  *
  * @param {string} label
- * @param {(n: number, sources: Array<Source<number>>)} fn
+ * @param {(n: number, sources: Array<Source<number>>) => void} fn
  * @param {number} count
  * @param {number} num_sources
  */
 function create_sbench_test(label, count, num_sources, fn) {
-	return async () => {
-		// Do 3 loops to warm up JIT
-		for (let i = 0; i < 3; i++) {
-			fn(count, create_sources(num_sources, []));
-		}
+	return {
+		label,
+		fn: async () => {
+			// Do 3 loops to warm up JIT
+			for (let i = 0; i < 3; i++) {
+				fn(count, create_sources(num_sources, []));
+			}
 
-		const { time, gc_time } = await fastest_test(10, () => {
-			const destroy = $.effect_root(() => {
-				for (let i = 0; i < 10; i++) {
-					fn(count, create_sources(num_sources, []));
-				}
+			return await fastest_test(10, () => {
+				const destroy = $.effect_root(() => {
+					for (let i = 0; i < 10; i++) {
+						fn(count, create_sources(num_sources, []));
+					}
+				});
+				destroy();
 			});
-			destroy();
-		});
-
-		return {
-			benchmark: label,
-			time,
-			gc_time
-		};
+		}
 	};
 }
 
diff --git a/benchmarking/benchmarks/reactivity/util.js b/benchmarking/benchmarks/reactivity/util.js
index 6a2e44f5ae..da5e5c51f5 100644
--- a/benchmarking/benchmarks/reactivity/util.js
+++ b/benchmarking/benchmarks/reactivity/util.js
@@ -15,34 +15,9 @@ export function busy() {
  */
 export function create_test(label, setup) {
 	return {
-		unowned: async () => {
-			// Do 10 loops to warm up JIT
-			for (let i = 0; i < 10; i++) {
-				const { run, destroy } = setup();
-				run(0);
-				destroy();
-			}
-
-			const { run, destroy } = setup();
-
-			const { time, gc_time } = await fastest_test(10, () => {
-				for (let i = 0; i < 1000; i++) {
-					run(i);
-				}
-			});
-
-			destroy();
-
-			return {
-				benchmark: `${label}_unowned`,
-				time,
-				gc_time
-			};
-		},
-		owned: async () => {
-			let run, destroy;
-
-			const destroy_owned = $.effect_root(() => {
+		unowned: {
+			label: `${label}_unowned`,
+			fn: async () => {
 				// Do 10 loops to warm up JIT
 				for (let i = 0; i < 10; i++) {
 					const { run, destroy } = setup();
@@ -50,24 +25,47 @@ export function create_test(label, setup) {
 					destroy();
 				}
 
-				({ run, destroy } = setup());
-			});
+				const { run, destroy } = setup();
+
+				const result = await fastest_test(10, () => {
+					for (let i = 0; i < 1000; i++) {
+						run(i);
+					}
+				});
 
-			const { time, gc_time } = await fastest_test(10, () => {
-				for (let i = 0; i < 1000; i++) {
-					run(i);
-				}
-			});
+				destroy();
+
+				return result;
+			}
+		},
+		owned: {
+			label: `${label}_owned`,
+			fn: async () => {
+				let run, destroy;
 
-			// @ts-ignore
-			destroy();
-			destroy_owned();
+				const destroy_owned = $.effect_root(() => {
+					// Do 10 loops to warm up JIT
+					for (let i = 0; i < 10; i++) {
+						const { run, destroy } = setup();
+						run(0);
+						destroy();
+					}
 
-			return {
-				benchmark: `${label}_owned`,
-				time,
-				gc_time
-			};
+					({ run, destroy } = setup());
+				});
+
+				const result = await fastest_test(10, () => {
+					for (let i = 0; i < 1000; i++) {
+						run(i);
+					}
+				});
+
+				// @ts-ignore
+				destroy();
+				destroy_owned();
+
+				return result;
+			}
 		}
 	};
 }
diff --git a/benchmarking/benchmarks/ssr/wrapper/wrapper_bench.js b/benchmarking/benchmarks/ssr/wrapper/wrapper_bench.js
index 6e790ee2b8..9a8dda617d 100644
--- a/benchmarking/benchmarks/ssr/wrapper/wrapper_bench.js
+++ b/benchmarking/benchmarks/ssr/wrapper/wrapper_bench.js
@@ -18,26 +18,23 @@ async function compile_svelte() {
 	return module.default;
 }
 
-export async function wrapper_bench() {
-	const App = await compile_svelte();
+export const wrapper_bench = {
+	label: 'wrapper_bench',
+	fn: async () => {
+		const App = await compile_svelte();
 
-	// Do 3 loops to warm up JIT
-	for (let i = 0; i < 3; i++) {
-		render(App);
-	}
-
-	const { time, gc_time } = await fastest_test(10, () => {
-		for (let i = 0; i < 100; i++) {
+		// Do 3 loops to warm up JIT
+		for (let i = 0; i < 3; i++) {
 			render(App);
 		}
-	});
 
-	return {
-		benchmark: 'wrapper_bench',
-		time,
-		gc_time
-	};
-}
+		return await fastest_test(10, () => {
+			for (let i = 0; i < 100; i++) {
+				render(App);
+			}
+		});
+	}
+};
 
 /**
  * @param {string} file
diff --git a/benchmarking/compare/runner.js b/benchmarking/compare/runner.js
index a2e8646379..11e40ed983 100644
--- a/benchmarking/compare/runner.js
+++ b/benchmarking/compare/runner.js
@@ -1,10 +1,13 @@
 import { reactivity_benchmarks } from '../benchmarks/reactivity/index.js';
 
 const results = [];
-for (const benchmark of reactivity_benchmarks) {
-	const result = await benchmark();
-	console.error(result.benchmark);
-	results.push(result);
+
+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} `);
+	results.push({ benchmark: benchmark.label, ...(await benchmark.fn()) });
+	process.stderr.write('\x1b[2K\r');
 }
 
 process.send(results);
diff --git a/benchmarking/run.js b/benchmarking/run.js
index f7b8128886..2b09f7c592 100644
--- a/benchmarking/run.js
+++ b/benchmarking/run.js
@@ -2,13 +2,28 @@ 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';
 
-let total_time = 0;
-let total_gc_time = 0;
+// e.g. `pnpm bench kairo` to only run the kairo benchmarks
+const filters = process.argv.slice(2);
 
 const suites = [
-	{ benchmarks: reactivity_benchmarks, name: 'reactivity benchmarks' },
-	{ benchmarks: ssr_benchmarks, name: 'server-side rendering benchmarks' }
-];
+	{
+		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);
@@ -16,6 +31,9 @@ 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;
 
+let total_time = 0;
+let total_gc_time = 0;
+
 $.push({}, true);
 
 try {
@@ -32,9 +50,9 @@ try {
 		console.log('='.repeat(TOTAL_WIDTH));
 
 		for (const benchmark of benchmarks) {
-			const results = await benchmark();
+			const results = await benchmark.fn();
 			console.log(
-				pad_right(results.benchmark, COLUMN_WIDTHS[0]) +
+				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])
 			);
diff --git a/package.json b/package.json
index aa9c8cafa3..24be8bd2bc 100644
--- a/package.json
+++ b/package.json
@@ -22,8 +22,8 @@
     "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",
-    "bench:compare": "node --allow-natives-syntax ./benchmarking/compare/index.js",
-    "bench:debug": "node --allow-natives-syntax --inspect-brk ./benchmarking/run.js"
+    "bench:compare": "NODE_ENV=production node --allow-natives-syntax ./benchmarking/compare/index.js",
+    "bench:debug": "NODE_ENV=production node --allow-natives-syntax --inspect-brk ./benchmarking/run.js"
   },
   "devDependencies": {
     "@changesets/cli": "^2.29.8",

From 5ce61868893b5d78cc139fbd76be3ef33f4ec124 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 21 Jan 2026 16:05:37 -0500
Subject: [PATCH 050/142] fix (#17507)

---
 .../reactivity/tests/repeated_deps.bench.js   | 35 +++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 benchmarking/benchmarks/reactivity/tests/repeated_deps.bench.js

diff --git a/benchmarking/benchmarks/reactivity/tests/repeated_deps.bench.js b/benchmarking/benchmarks/reactivity/tests/repeated_deps.bench.js
new file mode 100644
index 0000000000..a8fbcfdbd6
--- /dev/null
+++ b/benchmarking/benchmarks/reactivity/tests/repeated_deps.bench.js
@@ -0,0 +1,35 @@
+import assert from 'node:assert';
+import * as $ from 'svelte/internal/client';
+
+const ARRAY_SIZE = 1000;
+
+export default () => {
+	const signals = Array.from({ length: ARRAY_SIZE }, (_, i) => $.state(i));
+	const order = $.state(0);
+
+	// break skipped_deps fast path by changing order of reads
+	const total = $.derived(() => {
+		const ord = $.get(order);
+		let sum = 0;
+		for (let i = 0; i < ARRAY_SIZE; i++) {
+			sum += /** @type {number} */ ($.get(signals[(i + ord) % ARRAY_SIZE]));
+		}
+		return sum;
+	});
+
+	const destroy = $.effect_root(() => {
+		$.render_effect(() => {
+			$.get(total);
+		});
+	});
+
+	return {
+		destroy,
+		run() {
+			for (let i = 0; i < 5; i++) {
+				$.flush(() => $.set(order, i));
+				assert.equal($.get(total), (ARRAY_SIZE * (ARRAY_SIZE - 1)) / 2); // sum of 0..999
+			}
+		}
+	};
+};

From c9ebd6a88553a3041d68c6063ec095fdd601f4b7 Mon Sep 17 00:00:00 2001
From: Elliott Johnson <sejohnson@torchcloudconsulting.com>
Date: Wed, 21 Jan 2026 14:09:30 -0700
Subject: [PATCH 051/142] feat: export `parseCss` from `svelte/compiler`
 (#17496)

* feat: export  from

* changeset

* fix: Errors

* set_source, so state is correct if an error occurs

* simplify

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/loud-buses-guess.md                |   5 +
 packages/svelte/src/compiler/index.js         |  26 +++-
 .../src/compiler/phases/1-parse/index.js      |  14 ++
 .../src/compiler/phases/1-parse/read/style.js |  30 ++--
 packages/svelte/tests/css-parse.test.ts       | 138 ++++++++++++++++++
 packages/svelte/types/index.d.ts              |   6 +
 6 files changed, 205 insertions(+), 14 deletions(-)
 create mode 100644 .changeset/loud-buses-guess.md
 create mode 100644 packages/svelte/tests/css-parse.test.ts

diff --git a/.changeset/loud-buses-guess.md b/.changeset/loud-buses-guess.md
new file mode 100644
index 0000000000..d6c7c3d5a4
--- /dev/null
+++ b/.changeset/loud-buses-guess.md
@@ -0,0 +1,5 @@
+---
+'svelte': minor
+---
+
+feat: export `parseCss` from `svelte/compiler`
diff --git a/packages/svelte/src/compiler/index.js b/packages/svelte/src/compiler/index.js
index 9095a2a2f2..acfef6a320 100644
--- a/packages/svelte/src/compiler/index.js
+++ b/packages/svelte/src/compiler/index.js
@@ -3,8 +3,9 @@
 /** @import { AST } from './public.js' */
 import { walk as zimmerframe_walk } from 'zimmerframe';
 import { convert } from './legacy.js';
-import { parse as _parse } from './phases/1-parse/index.js';
+import { parse as _parse, Parser } from './phases/1-parse/index.js';
 import { remove_typescript_nodes } from './phases/1-parse/remove_typescript_nodes.js';
+import { parse_stylesheet } from './phases/1-parse/read/style.js';
 import { analyze_component, analyze_module } from './phases/2-analyze/index.js';
 import { transform_component, transform_module } from './phases/3-transform/index.js';
 import { validate_component_options, validate_module_options } from './validate-options.js';
@@ -118,6 +119,29 @@ export function parse(source, { modern, loose } = {}) {
 	return to_public_ast(source, ast, modern);
 }
 
+/**
+ * The parseCss function parses a CSS stylesheet, returning its abstract syntax tree.
+ *
+ * @param {string} source The CSS source code
+ * @returns {Omit<AST.CSS.StyleSheet, 'attributes' | 'content'>}
+ */
+export function parseCss(source) {
+	source = remove_bom(source);
+	state.reset({ warning: () => false, filename: undefined });
+
+	state.set_source(source);
+
+	const parser = Parser.forCss(source);
+	const children = parse_stylesheet(parser);
+
+	return {
+		type: 'StyleSheet',
+		start: 0,
+		end: source.length,
+		children
+	};
+}
+
 /**
  * @param {string} source
  * @param {AST.Root} ast
diff --git a/packages/svelte/src/compiler/phases/1-parse/index.js b/packages/svelte/src/compiler/phases/1-parse/index.js
index 3b5f83d58f..88b4352e8a 100644
--- a/packages/svelte/src/compiler/phases/1-parse/index.js
+++ b/packages/svelte/src/compiler/phases/1-parse/index.js
@@ -34,6 +34,20 @@ export class Parser {
 	/** */
 	index = 0;
 
+	/**
+	 * Creates a minimal parser instance for CSS-only parsing.
+	 * Skips Svelte component parsing setup.
+	 * @param {string} source
+	 * @returns {Parser}
+	 */
+	static forCss(source) {
+		const parser = Object.create(Parser.prototype);
+		parser.template = source;
+		parser.index = 0;
+		parser.loose = false;
+		return parser;
+	}
+
 	/** Whether we're parsing in TypeScript mode */
 	ts = false;
 
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 80ab234d92..c88a3707c1 100644
--- a/packages/svelte/src/compiler/phases/1-parse/read/style.js
+++ b/packages/svelte/src/compiler/phases/1-parse/read/style.js
@@ -24,10 +24,11 @@ const REGEX_HTML_COMMENT_CLOSE = /-->/;
  */
 export default function read_style(parser, start, attributes) {
 	const content_start = parser.index;
-	const children = read_body(parser, '</style');
+	const children = read_body(parser, (p) => p.match('</style') || p.index >= p.template.length);
 	const content_end = parser.index;
 
-	parser.read(/^<\/style\s*>/);
+	parser.eat('</style', true);
+	parser.read(/^\s*>/);
 
 	return {
 		type: 'StyleSheet',
@@ -46,20 +47,14 @@ export default function read_style(parser, start, attributes) {
 
 /**
  * @param {Parser} parser
- * @param {string} close
- * @returns {any[]}
+ * @param {(parser: Parser) => boolean} finished
+ * @returns {Array<AST.CSS.Rule | AST.CSS.Atrule>}
  */
-function read_body(parser, close) {
+function read_body(parser, finished) {
 	/** @type {Array<AST.CSS.Rule | AST.CSS.Atrule>} */
 	const children = [];
 
-	while (parser.index < parser.template.length) {
-		allow_comment_or_whitespace(parser);
-
-		if (parser.match(close)) {
-			return children;
-		}
-
+	while ((allow_comment_or_whitespace(parser), !finished(parser))) {
 		if (parser.match('@')) {
 			children.push(read_at_rule(parser));
 		} else {
@@ -67,7 +62,7 @@ function read_body(parser, close) {
 		}
 	}
 
-	e.expected_token(parser.template.length, close);
+	return children;
 }
 
 /**
@@ -627,3 +622,12 @@ function allow_comment_or_whitespace(parser) {
 		parser.allow_whitespace();
 	}
 }
+
+/**
+ * Parse standalone CSS content (not wrapped in `<style>`).
+ * @param {Parser} parser
+ * @returns {Array<AST.CSS.Rule | AST.CSS.Atrule>}
+ */
+export function parse_stylesheet(parser) {
+	return read_body(parser, (p) => p.index >= p.template.length);
+}
diff --git a/packages/svelte/tests/css-parse.test.ts b/packages/svelte/tests/css-parse.test.ts
new file mode 100644
index 0000000000..fcb9bdc010
--- /dev/null
+++ b/packages/svelte/tests/css-parse.test.ts
@@ -0,0 +1,138 @@
+import { assert, describe, it } from 'vitest';
+import { parseCss } from 'svelte/compiler';
+
+describe('parseCss', () => {
+	it('parses a simple rule', () => {
+		const ast = parseCss('div { color: red; }');
+		assert.equal(ast.type, 'StyleSheet');
+		assert.equal(ast.children.length, 1);
+		assert.equal(ast.children[0].type, 'Rule');
+	});
+
+	it('parses at-rules', () => {
+		const ast = parseCss('@media (min-width: 800px) { div { color: red; } }');
+		assert.equal(ast.children.length, 1);
+		assert.equal(ast.children[0].type, 'Atrule');
+		if (ast.children[0].type === 'Atrule') {
+			assert.equal(ast.children[0].name, 'media');
+		}
+	});
+
+	it('parses @import', () => {
+		const ast = parseCss("@import 'foo.css';");
+		assert.equal(ast.children.length, 1);
+		assert.equal(ast.children[0].type, 'Atrule');
+		if (ast.children[0].type === 'Atrule') {
+			assert.equal(ast.children[0].name, 'import');
+			assert.equal(ast.children[0].block, null);
+		}
+	});
+
+	it('parses multiple rules', () => {
+		const ast = parseCss('div { color: red; } span { color: blue; }');
+		assert.equal(ast.children.length, 2);
+	});
+
+	it('has correct start/end positions', () => {
+		const ast = parseCss('div { color: red; }');
+		assert.equal(ast.start, 0);
+		assert.equal(ast.end, 19);
+	});
+
+	it('strips BOM', () => {
+		const ast = parseCss('\uFEFFdiv { color: red; }');
+		assert.equal(ast.start, 0);
+		assert.equal(ast.end, 19);
+	});
+
+	it('parses nested rules', () => {
+		const ast = parseCss('div { color: red; span { color: blue; } }');
+		assert.equal(ast.children.length, 1);
+		const rule = ast.children[0];
+		assert.equal(rule.type, 'Rule');
+		if (rule.type === 'Rule') {
+			assert.equal(rule.block.children.length, 2); // declaration + nested rule
+		}
+	});
+
+	it('parses empty stylesheet', () => {
+		const ast = parseCss('');
+		assert.equal(ast.type, 'StyleSheet');
+		assert.equal(ast.children.length, 0);
+		assert.equal(ast.start, 0);
+		assert.equal(ast.end, 0);
+	});
+
+	it('parses whitespace-only stylesheet', () => {
+		const ast = parseCss('   \n\t  ');
+		assert.equal(ast.children.length, 0);
+	});
+
+	it('parses comments', () => {
+		const ast = parseCss('/* comment */ div { color: red; }');
+		assert.equal(ast.children.length, 1);
+		assert.equal(ast.children[0].type, 'Rule');
+	});
+
+	it('parses complex selectors', () => {
+		const ast = parseCss('div > span + p ~ a { color: red; }');
+		assert.equal(ast.children.length, 1);
+		const rule = ast.children[0];
+		if (rule.type === 'Rule') {
+			assert.equal(rule.prelude.type, 'SelectorList');
+			assert.equal(rule.prelude.children.length, 1);
+			// div > span + p ~ a has 4 relative selectors
+			assert.equal(rule.prelude.children[0].children.length, 4);
+		}
+	});
+
+	it('parses pseudo-classes and pseudo-elements', () => {
+		const ast = parseCss('div:hover::before { color: red; }');
+		assert.equal(ast.children.length, 1);
+		const rule = ast.children[0];
+		if (rule.type === 'Rule') {
+			const selectors = rule.prelude.children[0].children[0].selectors;
+			assert.equal(selectors.length, 3); // div, :hover, ::before
+			assert.equal(selectors[0].type, 'TypeSelector');
+			assert.equal(selectors[1].type, 'PseudoClassSelector');
+			assert.equal(selectors[2].type, 'PseudoElementSelector');
+		}
+	});
+
+	it('parses @keyframes', () => {
+		const ast = parseCss('@keyframes fade { from { opacity: 0; } to { opacity: 1; } }');
+		assert.equal(ast.children.length, 1);
+		assert.equal(ast.children[0].type, 'Atrule');
+		if (ast.children[0].type === 'Atrule') {
+			assert.equal(ast.children[0].name, 'keyframes');
+			assert.notEqual(ast.children[0].block, null);
+		}
+	});
+
+	it('parses class and id selectors', () => {
+		const ast = parseCss('.foo#bar { color: red; }');
+		assert.equal(ast.children.length, 1);
+		const rule = ast.children[0];
+		if (rule.type === 'Rule') {
+			const selectors = rule.prelude.children[0].children[0].selectors;
+			assert.equal(selectors.length, 2);
+			assert.equal(selectors[0].type, 'ClassSelector');
+			assert.equal(selectors[1].type, 'IdSelector');
+		}
+	});
+
+	it('parses attribute selectors', () => {
+		const ast = parseCss('[data-foo="bar"] { color: red; }');
+		assert.equal(ast.children.length, 1);
+		const rule = ast.children[0];
+		if (rule.type === 'Rule') {
+			const selectors = rule.prelude.children[0].children[0].selectors;
+			assert.equal(selectors.length, 1);
+			assert.equal(selectors[0].type, 'AttributeSelector');
+			if (selectors[0].type === 'AttributeSelector') {
+				assert.equal(selectors[0].name, 'data-foo');
+				assert.equal(selectors[0].value, 'bar');
+			}
+		}
+	});
+});
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index c0b89d8736..9e569126bb 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -884,6 +884,12 @@ declare module 'svelte/compiler' {
 		modern?: false;
 		loose?: boolean;
 	} | undefined): Record<string, any>;
+	/**
+	 * The parseCss function parses a CSS stylesheet, returning its abstract syntax tree.
+	 *
+	 * @param source The CSS source code
+	 * */
+	export function parseCss(source: string): Omit<AST.CSS.StyleSheet, "attributes" | "content">;
 	/**
 	 * @deprecated Replace this with `import { walk } from 'estree-walker'`
 	 * */

From d3776c1723c17736198e0bc96c2fb75c69b0756f Mon Sep 17 00:00:00 2001
From: Tensorworker <178221229+tensorworkerr@users.noreply.github.com>
Date: Wed, 21 Jan 2026 18:40:08 -0500
Subject: [PATCH 052/142] fix: handle non-string values in svelte:element this
 attribute (#17499)

* fix: handle non-string values in svelte:element this attribute

* chore: add changeset

* fix(review): throw error in DEV for invalid svelte:element tag, ignore in PROD

* chore: remove unused expected.html from test

* fix(review): refine validate.js logic

* fix(review): use else if (string) logic in server/index.js

* fix(review): swap validation order in compiler, revert runtime changes

* test: move reproduction to runtime-legacy per review

* Apply suggestion from @7nik

---------

Co-authored-by: tensorworker <tensorworker@proton.me>
Co-authored-by: 7nik <kfiiranet@gmail.com>
---
 .changeset/clever-cats-dance.md                 |  5 +++++
 .../client/visitors/SvelteElement.js            |  2 +-
 .../server/visitors/SvelteElement.js            |  2 +-
 .../_config.js                                  | 17 +++++++++++++++++
 .../main.svelte                                 |  5 +++++
 5 files changed, 29 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/clever-cats-dance.md
 create mode 100644 packages/svelte/tests/runtime-legacy/samples/dynamic-element-invalid-this-content/_config.js
 create mode 100644 packages/svelte/tests/runtime-legacy/samples/dynamic-element-invalid-this-content/main.svelte

diff --git a/.changeset/clever-cats-dance.md b/.changeset/clever-cats-dance.md
new file mode 100644
index 0000000000..3322608095
--- /dev/null
+++ b/.changeset/clever-cats-dance.md
@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+fix: handle non-string values in `svelte:element` `this` attribute
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 cfa79b73ca..c8192cf00a 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
@@ -117,10 +117,10 @@ export function SvelteElement(node, context) {
 	);
 
 	if (dev) {
+		statements.push(b.stmt(b.call('$.validate_dynamic_element_tag', get_tag)));
 		if (node.fragment.nodes.length > 0) {
 			statements.push(b.stmt(b.call('$.validate_void_dynamic_element', get_tag)));
 		}
-		statements.push(b.stmt(b.call('$.validate_dynamic_element_tag', get_tag)));
 	}
 
 	const location = dev && locator(node.start);
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js
index 6fc1ca5dfc..1ac15893f2 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js
@@ -29,10 +29,10 @@ export function SvelteElement(node, context) {
 			tag = b.id(tag_id);
 		}
 
+		context.state.init.push(b.stmt(b.call('$.validate_dynamic_element_tag', b.thunk(tag))));
 		if (node.fragment.nodes.length > 0) {
 			context.state.init.push(b.stmt(b.call('$.validate_void_dynamic_element', b.thunk(tag))));
 		}
-		context.state.init.push(b.stmt(b.call('$.validate_dynamic_element_tag', b.thunk(tag))));
 	}
 
 	const state = {
diff --git a/packages/svelte/tests/runtime-legacy/samples/dynamic-element-invalid-this-content/_config.js b/packages/svelte/tests/runtime-legacy/samples/dynamic-element-invalid-this-content/_config.js
new file mode 100644
index 0000000000..b0dcaa8fdc
--- /dev/null
+++ b/packages/svelte/tests/runtime-legacy/samples/dynamic-element-invalid-this-content/_config.js
@@ -0,0 +1,17 @@
+import { test } from '../../test';
+
+export default test({
+	mode: ['client', 'server'],
+
+	compileOptions: {
+		dev: true
+	},
+
+	get props() {
+		return { tag: true };
+	},
+
+	error:
+		'svelte_element_invalid_this_value\n' +
+		'The `this` prop on `<svelte:element>` must be a string, if defined'
+});
diff --git a/packages/svelte/tests/runtime-legacy/samples/dynamic-element-invalid-this-content/main.svelte b/packages/svelte/tests/runtime-legacy/samples/dynamic-element-invalid-this-content/main.svelte
new file mode 100644
index 0000000000..cc6736a497
--- /dev/null
+++ b/packages/svelte/tests/runtime-legacy/samples/dynamic-element-invalid-this-content/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	export let tag;
+</script>
+
+<svelte:element this={tag}>content</svelte:element>

From f679259232307b5e39ee6a6cc4d39bbd475ea1be Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 21 Jan 2026 19:30:36 -0500
Subject: [PATCH 053/142] fix: prevent duplicate dependencies without using
 array.includes (#17503)

* fix: prevent duplicate dependencies without using array.includes

* changeset
---
 .changeset/gold-coats-change.md                |  5 +++++
 packages/svelte/src/internal/client/runtime.js | 16 +++++++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/gold-coats-change.md

diff --git a/.changeset/gold-coats-change.md b/.changeset/gold-coats-change.md
new file mode 100644
index 0000000000..0415de9e7c
--- /dev/null
+++ b/.changeset/gold-coats-change.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: faster deduplication of dependencies
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 0e12324d72..6988c6247a 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -309,6 +309,20 @@ export function update_reaction(reaction) {
 		if (previous_reaction !== null && previous_reaction !== reaction) {
 			read_version++;
 
+			// update the `rv` of the previous reaction's deps — both existing and new —
+			// so that they are not added again
+			if (previous_reaction.deps !== null) {
+				for (let i = 0; i < previous_skipped_deps; i += 1) {
+					previous_reaction.deps[i].rv = read_version;
+				}
+			}
+
+			if (previous_deps !== null) {
+				for (const dep of previous_deps) {
+					dep.rv = read_version;
+				}
+			}
+
 			if (untracked_writes !== null) {
 				if (previous_untracked_writes === null) {
 					previous_untracked_writes = untracked_writes;
@@ -526,7 +540,7 @@ export function get(signal) {
 						skipped_deps++;
 					} else if (new_deps === null) {
 						new_deps = [signal];
-					} else if (!new_deps.includes(signal)) {
+					} else {
 						new_deps.push(signal);
 					}
 				}

From 0ce2313e35ae680ebd60f4632a593759a9462629 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 21 Jan 2026 19:31:23 -0500
Subject: [PATCH 054/142] chore: squelch hydration warnings (#17509)

* chore: squelch some hydration warnings

* squelch another warning
---
 .../hydration/samples/no-reset-debug/_config.js    | 14 +++++++++++++-
 packages/svelte/tests/hydration/test.ts            |  4 ++--
 .../hydratable-clobbering-complicated/main.svelte  | 11 ++++++++---
 3 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/packages/svelte/tests/hydration/samples/no-reset-debug/_config.js b/packages/svelte/tests/hydration/samples/no-reset-debug/_config.js
index f47bee71df..2bdb29e436 100644
--- a/packages/svelte/tests/hydration/samples/no-reset-debug/_config.js
+++ b/packages/svelte/tests/hydration/samples/no-reset-debug/_config.js
@@ -1,3 +1,15 @@
 import { test } from '../../test';
 
-export default test({});
+/** @type {typeof console.log} */
+let log;
+
+export default test({
+	before_test() {
+		log = console.log;
+		console.log = () => {};
+	},
+
+	after_test() {
+		console.log = log;
+	}
+});
diff --git a/packages/svelte/tests/hydration/test.ts b/packages/svelte/tests/hydration/test.ts
index d7257c71d3..16e4070303 100644
--- a/packages/svelte/tests/hydration/test.ts
+++ b/packages/svelte/tests/hydration/test.ts
@@ -53,6 +53,8 @@ const { test, run } = suite<HydrationTest>(async (config, cwd) => {
 		await compile_directory(cwd, 'server', config.compileOptions);
 	}
 
+	config.before_test?.();
+
 	const target = window.document.body;
 	const head = window.document.head;
 
@@ -72,8 +74,6 @@ const { test, run } = suite<HydrationTest>(async (config, cwd) => {
 		head.innerHTML = override_head ?? rendered.head;
 	}
 
-	config.before_test?.();
-
 	try {
 		const snapshot = config.snapshot ? config.snapshot(target) : {};
 
diff --git a/packages/svelte/tests/server-side-rendering/samples/hydratable-clobbering-complicated/main.svelte b/packages/svelte/tests/server-side-rendering/samples/hydratable-clobbering-complicated/main.svelte
index 358488c3ac..64d30b2a7f 100644
--- a/packages/svelte/tests/server-side-rendering/samples/hydratable-clobbering-complicated/main.svelte
+++ b/packages/svelte/tests/server-side-rendering/samples/hydratable-clobbering-complicated/main.svelte
@@ -1,16 +1,21 @@
 <script lang="ts">
     import { hydratable } from 'svelte';
 
-    hydratable('key', () => Promise.resolve({
+    const a = await hydratable('key', () => Promise.resolve({
         nested: Promise.resolve({
             one: Promise.resolve(1),
         }),
         two: Promise.resolve(2),
     }));
-    hydratable('key', () => Promise.resolve({
+    const b = await hydratable('key', () => Promise.resolve({
         nested: Promise.resolve({
             one: Promise.resolve(2),
         }),
         two: Promise.resolve(2),
     }));
-</script>
\ No newline at end of file
+</script>
+
+<p>{await (await (a.nested)).one}</p>
+<p>{await a.two}</p>
+<p>{await (await (b.nested)).one}</p>
+<p>{await b.two}</p>

From c1fab8caae8334ebc1db7fb37d618ca204e461ab Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Wed, 21 Jan 2026 22:03:34 -0500
Subject: [PATCH 055/142] Version Packages (#17508)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/clever-cats-dance.md |  5 -----
 .changeset/gold-coats-change.md |  5 -----
 .changeset/loud-buses-guess.md  |  5 -----
 packages/svelte/CHANGELOG.md    | 12 ++++++++++++
 packages/svelte/package.json    |  2 +-
 packages/svelte/src/version.js  |  2 +-
 6 files changed, 14 insertions(+), 17 deletions(-)
 delete mode 100644 .changeset/clever-cats-dance.md
 delete mode 100644 .changeset/gold-coats-change.md
 delete mode 100644 .changeset/loud-buses-guess.md

diff --git a/.changeset/clever-cats-dance.md b/.changeset/clever-cats-dance.md
deleted file mode 100644
index 3322608095..0000000000
--- a/.changeset/clever-cats-dance.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-"svelte": patch
----
-
-fix: handle non-string values in `svelte:element` `this` attribute
diff --git a/.changeset/gold-coats-change.md b/.changeset/gold-coats-change.md
deleted file mode 100644
index 0415de9e7c..0000000000
--- a/.changeset/gold-coats-change.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: faster deduplication of dependencies
diff --git a/.changeset/loud-buses-guess.md b/.changeset/loud-buses-guess.md
deleted file mode 100644
index d6c7c3d5a4..0000000000
--- a/.changeset/loud-buses-guess.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': minor
----
-
-feat: export `parseCss` from `svelte/compiler`
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index d019b7883f..21cbb4ee66 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,17 @@
 # svelte
 
+## 5.48.0
+
+### Minor Changes
+
+- feat: export `parseCss` from `svelte/compiler` ([#17496](https://github.com/sveltejs/svelte/pull/17496))
+
+### Patch Changes
+
+- fix: handle non-string values in `svelte:element` `this` attribute ([#17499](https://github.com/sveltejs/svelte/pull/17499))
+
+- fix: faster deduplication of dependencies ([#17503](https://github.com/sveltejs/svelte/pull/17503))
+
 ## 5.47.1
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 38cac7b1cd..bbb519f8e8 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": "5.47.1",
+  "version": "5.48.0",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index a5360f7195..c1ced8dad3 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 = '5.47.1';
+export const VERSION = '5.48.0';
 export const PUBLIC_VERSION = '5';

From d95887deb6e1f6222b6aadef6c4493f43755fae3 Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Thu, 22 Jan 2026 19:30:44 +0100
Subject: [PATCH 056/142] fix: hoist snippets above const in same block
 (#17516)

* fix: hoist snippets above const in same block

* fix: type error
---
 .changeset/blue-parts-double.md                            | 5 +++++
 .../compiler/phases/3-transform/client/transform-client.js | 1 +
 .../src/compiler/phases/3-transform/client/types.d.ts      | 2 ++
 .../phases/3-transform/client/visitors/Fragment.js         | 7 ++++---
 .../phases/3-transform/client/visitors/RegularElement.js   | 3 ++-
 .../phases/3-transform/client/visitors/SnippetBlock.js     | 2 +-
 .../phases/3-transform/client/visitors/SvelteBoundary.js   | 2 +-
 .../phases/3-transform/client/visitors/shared/component.js | 2 +-
 .../samples/snippet-const-same-block/_config.js            | 5 +++++
 .../samples/snippet-const-same-block/main.svelte           | 4 ++++
 10 files changed, 26 insertions(+), 7 deletions(-)
 create mode 100644 .changeset/blue-parts-double.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/snippet-const-same-block/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/snippet-const-same-block/main.svelte

diff --git a/.changeset/blue-parts-double.md b/.changeset/blue-parts-double.md
new file mode 100644
index 0000000000..223e51fdae
--- /dev/null
+++ b/.changeset/blue-parts-double.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: hoist snippets above const in same block
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 5c00aa591f..fc202f1bc2 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
@@ -170,6 +170,7 @@ export function client_component(analysis, options) {
 		// these are set inside the `Fragment` visitor, and cannot be used until then
 		init: /** @type {any} */ (null),
 		consts: /** @type {any} */ (null),
+		snippets: /** @type {any} */ (null),
 		let_directives: /** @type {any} */ (null),
 		update: /** @type {any} */ (null),
 		after_update: /** @type {any} */ (null),
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 d64b1d4126..4438ec015b 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
@@ -49,6 +49,8 @@ export interface ComponentClientTransformState extends ClientTransformState {
 	readonly update: Statement[];
 	/** Stuff that happens after the render effect (control blocks, dynamic elements, bindings, actions, etc) */
 	readonly after_update: Statement[];
+	/** Transformed `{#snippets }` declarations */
+	readonly snippets: Statement[];
 	/** Transformed `{@const }` declarations */
 	readonly consts: Statement[];
 	/** Transformed async `{@const }` declarations (if any) and those coming after them */
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 18017ea557..79a443967c 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
@@ -1,13 +1,13 @@
 /** @import { Expression, Statement } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { ComponentClientTransformState, ComponentContext } from '../types' */
-import { TEMPLATE_FRAGMENT, TEMPLATE_USE_IMPORT_NODE } from '../../../../../constants.js';
 import * as b from '#compiler/builders';
+import { TEMPLATE_FRAGMENT, TEMPLATE_USE_IMPORT_NODE } from '../../../../../constants.js';
 import { clean_nodes, infer_namespace } from '../../utils.js';
 import { transform_template } from '../transform-template/index.js';
+import { Template } from '../transform-template/template.js';
 import { process_children } from './shared/fragment.js';
 import { build_render_statement, Memoizer } from './shared/utils.js';
-import { Template } from '../transform-template/template.js';
 
 /**
  * @param {AST.Fragment} node
@@ -60,6 +60,7 @@ export function Fragment(node, context) {
 	const state = {
 		...context.state,
 		init: [],
+		snippets: [],
 		consts: [],
 		let_directives: [],
 		update: [],
@@ -150,7 +151,7 @@ export function Fragment(node, context) {
 		}
 	}
 
-	body.push(...state.let_directives, ...state.consts);
+	body.push(...state.snippets, ...state.let_directives, ...state.consts);
 
 	if (state.async_consts && state.async_consts.thunks.length > 0) {
 		body.push(b.var(state.async_consts.id, b.call('$.run', b.array(state.async_consts.thunks))));
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 1faf44b902..720522beaf 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
@@ -329,7 +329,7 @@ export function RegularElement(node, context) {
 	);
 
 	/** @type {typeof state} */
-	const child_state = { ...state, init: [], update: [], after_update: [] };
+	const child_state = { ...state, init: [], update: [], after_update: [], snippets: [] };
 
 	for (const node of hoisted) {
 		context.visit(node, child_state);
@@ -441,6 +441,7 @@ export function RegularElement(node, context) {
 		// Wrap children in `{...}` to avoid declaration conflicts
 		context.state.init.push(
 			b.block([
+				...child_state.snippets,
 				...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/SnippetBlock.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/SnippetBlock.js
index 1af737f05b..6c3a48c5ea 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/SnippetBlock.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/SnippetBlock.js
@@ -89,6 +89,6 @@ export function SnippetBlock(node, context) {
 			context.state.instance_level_snippets.push(declaration);
 		}
 	} else {
-		context.state.init.push(declaration);
+		context.state.snippets.push(declaration);
 	}
 }
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 d64fcda2e8..f929a3bc47 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
@@ -77,7 +77,7 @@ export function SvelteBoundary(node, context) {
 				/** @type {Statement[]} */
 				const statements = [];
 
-				context.visit(child, { ...context.state, init: statements });
+				context.visit(child, { ...context.state, snippets: statements });
 
 				const snippet = /** @type {VariableDeclaration} */ (statements[0]);
 
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/component.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/component.js
index 4651f6f733..bb72794af8 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/component.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/component.js
@@ -333,7 +333,7 @@ export function build_component(node, component_name, loc, context) {
 			// can be used as props without creating conflicts
 			context.visit(child, {
 				...context.state,
-				init: snippet_declarations
+				snippets: snippet_declarations
 			});
 
 			push_prop(b.prop('init', child.expression, child.expression));
diff --git a/packages/svelte/tests/runtime-runes/samples/snippet-const-same-block/_config.js b/packages/svelte/tests/runtime-runes/samples/snippet-const-same-block/_config.js
new file mode 100644
index 0000000000..27f013d6d1
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/snippet-const-same-block/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	test() {}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/snippet-const-same-block/main.svelte b/packages/svelte/tests/runtime-runes/samples/snippet-const-same-block/main.svelte
new file mode 100644
index 0000000000..70c7d64f18
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/snippet-const-same-block/main.svelte
@@ -0,0 +1,4 @@
+{#if true}
+	{@const xx = test}
+	{#snippet test()}{/snippet}
+{/if}

From f9cc2d25b9b348fb6c1c2b6b6f973804e6a5ed8c Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Thu, 22 Jan 2026 16:05:26 -0500
Subject: [PATCH 057/142] fix: better code generation for const tags with async
 dependencies (#17518)

---
 .changeset/witty-streets-carry.md             |  5 +++
 .../3-transform/client/visitors/ConstTag.js   | 16 ++++++---
 .../3-transform/server/visitors/ConstTag.js   |  6 ++--
 .../snapshot/samples/async-const/_config.js   |  3 ++
 .../_expected/client/index.svelte.js          | 35 +++++++++++++++++++
 .../_expected/server/index.svelte.js          | 33 +++++++++++++++++
 .../snapshot/samples/async-const/index.svelte |  6 ++++
 7 files changed, 97 insertions(+), 7 deletions(-)
 create mode 100644 .changeset/witty-streets-carry.md
 create mode 100644 packages/svelte/tests/snapshot/samples/async-const/_config.js
 create mode 100644 packages/svelte/tests/snapshot/samples/async-const/_expected/client/index.svelte.js
 create mode 100644 packages/svelte/tests/snapshot/samples/async-const/_expected/server/index.svelte.js
 create mode 100644 packages/svelte/tests/snapshot/samples/async-const/index.svelte

diff --git a/.changeset/witty-streets-carry.md b/.changeset/witty-streets-carry.md
new file mode 100644
index 0000000000..f02d998409
--- /dev/null
+++ b/.changeset/witty-streets-carry.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: better code generation for const tags with async dependencies
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 a9f922623e..ffeffe6ea4 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
@@ -1,4 +1,4 @@
-/** @import { Pattern } from 'estree' */
+/** @import { Expression, Identifier, Pattern } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types' */
 /** @import { ExpressionMetadata } from '../../../nodes.js' */
@@ -88,8 +88,8 @@ export function ConstTag(node, context) {
 
 /**
  * @param {ComponentContext['state']} state
- * @param {import('estree').Identifier} id
- * @param {import('estree').Expression} expression
+ * @param {Identifier} id
+ * @param {Expression} expression
  * @param {ExpressionMetadata} metadata
  * @param {import('#compiler').Binding[]} bindings
  */
@@ -99,7 +99,9 @@ function add_const_declaration(state, id, expression, metadata, bindings) {
 	const after = dev ? [b.stmt(b.call('$.get', id))] : [];
 
 	const has_await = metadata.has_await;
-	const blockers = [...metadata.dependencies].map((dep) => dep.blocker).filter((b) => b !== null);
+	const blockers = [...metadata.dependencies]
+		.map((dep) => dep.blocker)
+		.filter((b) => b !== null && b.object !== state.async_consts?.id);
 
 	if (has_await || state.async_consts || blockers.length > 0) {
 		const run = (state.async_consts ??= {
@@ -112,7 +114,11 @@ function add_const_declaration(state, id, expression, metadata, bindings) {
 		const assignment = b.assignment('=', id, expression);
 		const body = after.length === 0 ? assignment : b.block([b.stmt(assignment), ...after]);
 
-		if (blockers.length > 0) run.thunks.push(b.thunk(b.call('Promise.all', b.array(blockers))));
+		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))));
+		}
 
 		run.thunks.push(b.thunk(body, has_await));
 
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 fdc31e5238..d2ff9a10b4 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
@@ -15,7 +15,7 @@ export function ConstTag(node, context) {
 	const has_await = node.metadata.expression.has_await;
 	const blockers = [...node.metadata.expression.dependencies]
 		.map((dep) => dep.blocker)
-		.filter((b) => b !== null);
+		.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 ??= {
@@ -30,7 +30,9 @@ export function ConstTag(node, context) {
 			context.state.init.push(b.let(identifier.name));
 		}
 
-		if (blockers.length > 0) {
+		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))));
 		}
 
diff --git a/packages/svelte/tests/snapshot/samples/async-const/_config.js b/packages/svelte/tests/snapshot/samples/async-const/_config.js
new file mode 100644
index 0000000000..2e30bbeb16
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/async-const/_config.js
@@ -0,0 +1,3 @@
+import { test } from '../../test';
+
+export default test({ compileOptions: { experimental: { async: true } } });
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
new file mode 100644
index 0000000000..8bd7e97780
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/async-const/_expected/client/index.svelte.js
@@ -0,0 +1,35 @@
+import 'svelte/internal/disclose-version';
+import 'svelte/internal/flags/async';
+import * as $ from 'svelte/internal/client';
+
+var root_1 = $.from_html(`<p> </p>`);
+
+export default function Async_const($$anchor) {
+	var fragment = $.comment();
+	var node = $.first_child(fragment);
+
+	{
+		var consequent = ($$anchor) => {
+			let a;
+			let b;
+
+			var promises = $.run([
+				async () => a = (await $.save($.async_derived(async () => (await $.save(1))())))(),
+				() => b = $.derived(() => $.get(a) + 1)
+			]);
+
+			var p = root_1();
+			var text = $.child(p, true);
+
+			$.reset(p);
+			$.template_effect(() => $.set_text(text, $.get(b)), void 0, void 0, [promises[1]]);
+			$.append($$anchor, p);
+		};
+
+		$.if(node, ($$render) => {
+			if (true) $$render(consequent);
+		});
+	}
+
+	$.append($$anchor, fragment);
+}
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/async-const/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-const/_expected/server/index.svelte.js
new file mode 100644
index 0000000000..a726b903bc
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/async-const/_expected/server/index.svelte.js
@@ -0,0 +1,33 @@
+import 'svelte/internal/flags/async';
+import * as $ from 'svelte/internal/server';
+
+export default function Async_const($$renderer) {
+	if (true) {
+		$$renderer.push('<!--[-->');
+
+		let a;
+		let b;
+
+		var promises = $$renderer.run([
+			async () => {
+				a = (await $.save(1))();
+			},
+
+			() => {
+				b = a + 1;
+			}
+		]);
+
+		$$renderer.push(`<p>`);
+
+		$$renderer.async([promises[1]], ($$renderer) => {
+			$$renderer.push(() => $.escape(b));
+		});
+
+		$$renderer.push(`</p>`);
+	} else {
+		$$renderer.push('<!--[!-->');
+	}
+
+	$$renderer.push(`<!--]-->`);
+}
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/async-const/index.svelte b/packages/svelte/tests/snapshot/samples/async-const/index.svelte
new file mode 100644
index 0000000000..cf1bb40d88
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/async-const/index.svelte
@@ -0,0 +1,6 @@
+{#if true}
+	{@const a = await 1}
+	{@const b = a + 1}
+
+	<p>{b}</p>
+{/if}

From 7719d0312ca27b9347a04290e94a6a9097fefe94 Mon Sep 17 00:00:00 2001
From: David <david@hmnd.io>
Date: Thu, 22 Jan 2026 14:34:56 -0800
Subject: [PATCH 058/142] fix: perf regression with async mode (#17461)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* perf: use Set for new_deps to avoid O(n) includes check

* fix: only call revive() when batch is no longer deferred

* fix: avoid unnecessary async tracking when blockers are already settled

* add changeset

* only record promises as settled after cleanup is complete

* don't flush when already flushing

* skip settled blockers more aggressively

* batch decrement and pending count updates to reduce flush pressure

* extract new_deps changes to a separate PR

* remove changeset that applies to the other branch

* mark promises as settled as they settle — at the end is too late to do any good

* remove unnecessary microtask

* extract batch changes to separate PR

* this too

* avoid assigning to parameter

* wrong promise added to settled_promises due to reassignment

* WIP

* WIP

* fix

* unused

* oops

* bad import

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/ten-horses-cross.md                |   5 +
 .../3-transform/client/visitors/ConstTag.js   |   4 +-
 .../src/internal/client/dom/blocks/async.js   |   9 +-
 .../client/dom/elements/attributes.js         |   4 +-
 .../src/internal/client/reactivity/async.js   | 105 +++++++++++-------
 .../src/internal/client/reactivity/effects.js |   6 +-
 .../src/internal/client/reactivity/types.d.ts |   5 +
 .../svelte/src/internal/client/validate.js    |   3 +-
 8 files changed, 91 insertions(+), 50 deletions(-)
 create mode 100644 .changeset/ten-horses-cross.md

diff --git a/.changeset/ten-horses-cross.md b/.changeset/ten-horses-cross.md
new file mode 100644
index 0000000000..5502c5887b
--- /dev/null
+++ b/.changeset/ten-horses-cross.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: avoid async overhead for already settled promises
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 ffeffe6ea4..d2bd3c10dc 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
@@ -115,9 +115,9 @@ function add_const_declaration(state, id, expression, metadata, bindings) {
 		const body = after.length === 0 ? assignment : b.block([b.stmt(assignment), ...after]);
 
 		if (blockers.length === 1) {
-			run.thunks.push(b.thunk(/** @type {Expression} */ (blockers[0])));
+			run.thunks.push(b.thunk(b.member(/** @type {Expression} */ (blockers[0]), 'promise')));
 		} else if (blockers.length > 0) {
-			run.thunks.push(b.thunk(b.call('Promise.all', b.array(blockers))));
+			run.thunks.push(b.thunk(b.call('$.wait', b.array(blockers))));
 		}
 
 		run.thunks.push(b.thunk(body, has_await));
diff --git a/packages/svelte/src/internal/client/dom/blocks/async.js b/packages/svelte/src/internal/client/dom/blocks/async.js
index 3bc1eecba7..c2ae07fd17 100644
--- a/packages/svelte/src/internal/client/dom/blocks/async.js
+++ b/packages/svelte/src/internal/client/dom/blocks/async.js
@@ -1,4 +1,4 @@
-/** @import { TemplateNode, Value } from '#client' */
+/** @import { Blocker, TemplateNode, Value } from '#client' */
 import { flatten } from '../../reactivity/async.js';
 import { Batch, current_batch } from '../../reactivity/batch.js';
 import { get } from '../../runtime.js';
@@ -14,11 +14,16 @@ import { get_boundary } from './boundary.js';
 
 /**
  * @param {TemplateNode} node
- * @param {Array<Promise<void>>} blockers
+ * @param {Blocker[]} blockers
  * @param {Array<() => Promise<any>>} expressions
  * @param {(anchor: TemplateNode, ...deriveds: Value[]) => void} fn
  */
 export function async(node, blockers = [], expressions = [], fn) {
+	if (expressions.length === 0 && blockers.every((b) => b.settled)) {
+		fn(node);
+		return;
+	}
+
 	var boundary = get_boundary();
 	var batch = /** @type {Batch} */ (current_batch);
 	var blocking = boundary.is_rendered();
diff --git a/packages/svelte/src/internal/client/dom/elements/attributes.js b/packages/svelte/src/internal/client/dom/elements/attributes.js
index c1ab97dc61..6f1fa7391e 100644
--- a/packages/svelte/src/internal/client/dom/elements/attributes.js
+++ b/packages/svelte/src/internal/client/dom/elements/attributes.js
@@ -1,4 +1,4 @@
-/** @import { Effect } from '#client' */
+/** @import { Blocker, Effect } from '#client' */
 import { DEV } from 'esm-env';
 import { hydrating, set_hydrating } from '../hydration.js';
 import { get_descriptors, get_prototype_of } from '../../../shared/utils.js';
@@ -483,7 +483,7 @@ function set_attributes(
  * @param {(...expressions: any) => Record<string | symbol, any>} fn
  * @param {Array<() => any>} sync
  * @param {Array<() => Promise<any>>} async
- * @param {Array<Promise<void>>} blockers
+ * @param {Blocker[]} blockers
  * @param {string} [css_hash]
  * @param {boolean} [should_remove_defaults]
  * @param {boolean} [skip_warning]
diff --git a/packages/svelte/src/internal/client/reactivity/async.js b/packages/svelte/src/internal/client/reactivity/async.js
index 334bf8f145..b6eba3bf8a 100644
--- a/packages/svelte/src/internal/client/reactivity/async.js
+++ b/packages/svelte/src/internal/client/reactivity/async.js
@@ -1,4 +1,4 @@
-/** @import { Effect, TemplateNode, Value } from '#client' */
+/** @import { Blocker, Effect, Value } from '#client' */
 import { DESTROYED, STALE_REACTION } from '#client/constants';
 import { DEV } from 'esm-env';
 import {
@@ -27,7 +27,7 @@ import {
 import { aborted } from './effects.js';
 
 /**
- * @param {Array<Promise<void>>} blockers
+ * @param {Blocker[]} blockers
  * @param {Array<() => any>} sync
  * @param {Array<() => Promise<any>>} async
  * @param {(values: Value[]) => any} fn
@@ -35,7 +35,10 @@ import { aborted } from './effects.js';
 export function flatten(blockers, sync, async, fn) {
 	const d = is_runes() ? derived : derived_safe_equal;
 
-	if (async.length === 0 && blockers.length === 0) {
+	// Filter out already-settled blockers - no need to wait for them
+	var pending = blockers.filter((b) => !b.settled);
+
+	if (async.length === 0 && pending.length === 0) {
 		fn(sync.map(d));
 		return;
 	}
@@ -44,47 +47,52 @@ export function flatten(blockers, sync, async, fn) {
 	var parent = /** @type {Effect} */ (active_effect);
 
 	var restore = capture();
+	var blocker_promise =
+		pending.length === 1
+			? pending[0].promise
+			: pending.length > 1
+				? Promise.all(pending.map((b) => b.promise))
+				: null;
+
+	/** @param {Value[]} values */
+	function finish(values) {
+		restore();
 
-	function run() {
-		Promise.all(async.map((expression) => async_derived(expression)))
-			.then((result) => {
-				restore();
+		try {
+			fn(values);
+		} catch (error) {
+			if ((parent.f & DESTROYED) === 0) {
+				invoke_error_boundary(error, parent);
+			}
+		}
 
-				try {
-					fn([...sync.map(d), ...result]);
-				} catch (error) {
-					// ignore errors in blocks that have already been destroyed
-					if ((parent.f & DESTROYED) === 0) {
-						invoke_error_boundary(error, parent);
-					}
-				}
+		batch?.deactivate();
+		unset_context();
+	}
 
-				batch?.deactivate();
-				unset_context();
-			})
-			.catch((error) => {
-				invoke_error_boundary(error, parent);
-			});
+	// Fast path: blockers but no async expressions
+	if (async.length === 0) {
+		/** @type {Promise<any>} */ (blocker_promise).then(() => finish(sync.map(d)));
+		return;
 	}
 
-	if (blockers.length > 0) {
-		Promise.all(blockers).then(() => {
-			restore();
+	// Full path: has async expressions
+	function run() {
+		restore();
+		Promise.all(async.map((expression) => async_derived(expression)))
+			.then((result) => finish([...sync.map(d), ...result]))
+			.catch((error) => invoke_error_boundary(error, parent));
+	}
 
-			try {
-				return run();
-			} finally {
-				batch?.deactivate();
-				unset_context();
-			}
-		});
+	if (blocker_promise) {
+		blocker_promise.then(run);
 	} else {
 		run();
 	}
 }
 
 /**
- * @param {Array<Promise<void>>} blockers
+ * @param {Blocker[]} blockers
  * @param {(values: Value[]) => any} fn
  */
 export function run_after_blockers(blockers, fn) {
@@ -239,7 +247,13 @@ export function run(thunks) {
 
 	var promise = Promise.resolve(thunks[0]()).catch(handle_error);
 
-	var promises = [promise];
+	/** @type {Blocker} */
+	var blocker = { promise, settled: false };
+	var blockers = [blocker];
+
+	promise.finally(() => {
+		blocker.settled = true;
+	});
 
 	for (const fn of thunks.slice(1)) {
 		promise = promise
@@ -255,13 +269,17 @@ export function run(thunks) {
 				restore();
 				return fn();
 			})
-			.catch(handle_error)
-			.finally(() => {
-				unset_context();
-				current_batch?.deactivate();
-			});
+			.catch(handle_error);
+
+		const blocker = { promise, settled: false };
+		blockers.push(blocker);
 
-		promises.push(promise);
+		promise.finally(() => {
+			blocker.settled = true;
+
+			unset_context();
+			current_batch?.deactivate();
+		});
 	}
 
 	promise
@@ -273,5 +291,12 @@ export function run(thunks) {
 			batch.decrement(blocking);
 		});
 
-	return promises;
+	return blockers;
+}
+
+/**
+ * @param {Blocker[]} blockers
+ */
+export function wait(blockers) {
+	return Promise.all(blockers.map((b) => b.promise));
 }
diff --git a/packages/svelte/src/internal/client/reactivity/effects.js b/packages/svelte/src/internal/client/reactivity/effects.js
index 4cba446afc..5b8dee07b9 100644
--- a/packages/svelte/src/internal/client/reactivity/effects.js
+++ b/packages/svelte/src/internal/client/reactivity/effects.js
@@ -1,4 +1,4 @@
-/** @import { ComponentContext, ComponentContextLegacy, Derived, Effect, TemplateNode, TransitionManager } from '#client' */
+/** @import { Blocker, ComponentContext, ComponentContextLegacy, Derived, Effect, TemplateNode, TransitionManager } from '#client' */
 import {
 	is_dirty,
 	active_effect,
@@ -361,7 +361,7 @@ export function render_effect(fn, flags = 0) {
  * @param {(...expressions: any) => void | (() => void)} fn
  * @param {Array<() => any>} sync
  * @param {Array<() => Promise<any>>} async
- * @param {Array<Promise<void>>} blockers
+ * @param {Blocker[]} blockers
  */
 export function template_effect(fn, sync = [], async = [], blockers = []) {
 	flatten(blockers, sync, async, (values) => {
@@ -374,7 +374,7 @@ export function template_effect(fn, sync = [], async = [], blockers = []) {
  * @param {(...expressions: any) => void | (() => void)} fn
  * @param {Array<() => any>} sync
  * @param {Array<() => Promise<any>>} async
- * @param {Array<Promise<void>>} blockers
+ * @param {Blocker[]} blockers
  */
 export function deferred_template_effect(fn, sync = [], async = [], blockers = []) {
 	var batch = /** @type {Batch} */ (current_batch);
diff --git a/packages/svelte/src/internal/client/reactivity/types.d.ts b/packages/svelte/src/internal/client/reactivity/types.d.ts
index 908576922f..8477917991 100644
--- a/packages/svelte/src/internal/client/reactivity/types.d.ts
+++ b/packages/svelte/src/internal/client/reactivity/types.d.ts
@@ -103,3 +103,8 @@ export interface Effect extends Reaction {
 export type Source<V = unknown> = Value<V>;
 
 export type MaybeSource<T = unknown> = T | Source<T>;
+
+export interface Blocker {
+	promise: Promise<any>;
+	settled: boolean;
+}
diff --git a/packages/svelte/src/internal/client/validate.js b/packages/svelte/src/internal/client/validate.js
index 0daecdb480..48a44db304 100644
--- a/packages/svelte/src/internal/client/validate.js
+++ b/packages/svelte/src/internal/client/validate.js
@@ -1,3 +1,4 @@
+/** @import { Blocker } from '#client' */
 import { dev_current_component_function } from './context.js';
 import { is_array } from '../shared/utils.js';
 import * as e from './errors.js';
@@ -41,7 +42,7 @@ export function validate_each_keys(collection, key_fn) {
 
 /**
  * @param {string} binding
- * @param {Array<Promise<void>>} blockers
+ * @param {Blocker[]} blockers
  * @param {() => Record<string, any>} get_object
  * @param {() => string} get_property
  * @param {number} line

From 1ed458edc7a24a2366008130326d87dcbb416321 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Thu, 22 Jan 2026 21:30:02 -0500
Subject: [PATCH 059/142] chore: remove `set_is_updating_effect` (#17459)

---
 .../src/internal/client/reactivity/batch.js   |  5 ----
 .../src/internal/client/reactivity/sources.js | 28 ++++++-------------
 .../svelte/src/internal/client/runtime.js     | 15 ++--------
 3 files changed, 11 insertions(+), 37 deletions(-)

diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 4c50781817..5a041f9703 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -27,8 +27,6 @@ import {
 	get,
 	increment_write_version,
 	is_dirty,
-	is_updating_effect,
-	set_is_updating_effect,
 	update_effect
 } from '../runtime.js';
 import * as e from '../errors.js';
@@ -561,14 +559,12 @@ export function flushSync(fn) {
 }
 
 function flush_effects() {
-	var was_updating_effect = is_updating_effect;
 	is_flushing = true;
 
 	var source_stacks = DEV ? new Set() : null;
 
 	try {
 		var flush_count = 0;
-		set_is_updating_effect(true);
 
 		while (queued_root_effects.length > 0) {
 			var batch = Batch.ensure();
@@ -612,7 +608,6 @@ function flush_effects() {
 		}
 	} finally {
 		is_flushing = false;
-		set_is_updating_effect(was_updating_effect);
 
 		last_scheduled_effect = null;
 
diff --git a/packages/svelte/src/internal/client/reactivity/sources.js b/packages/svelte/src/internal/client/reactivity/sources.js
index 6333962f41..7604c9e90b 100644
--- a/packages/svelte/src/internal/client/reactivity/sources.js
+++ b/packages/svelte/src/internal/client/reactivity/sources.js
@@ -13,9 +13,7 @@ import {
 	is_dirty,
 	untracking,
 	is_destroying_effect,
-	push_reaction_value,
-	set_is_updating_effect,
-	is_updating_effect
+	push_reaction_value
 } from '../runtime.js';
 import { equals, safe_equals } from './equality.js';
 import {
@@ -261,25 +259,17 @@ export function internal_set(source, value) {
 
 export function flush_eager_effects() {
 	eager_effects_deferred = false;
-	var prev_is_updating_effect = is_updating_effect;
-	set_is_updating_effect(true);
 
-	const inspects = Array.from(eager_effects);
-
-	try {
-		for (const effect of inspects) {
-			// Mark clean inspect-effects as maybe dirty and then check their dirtiness
-			// instead of just updating the effects - this way we avoid overfiring.
-			if ((effect.f & CLEAN) !== 0) {
-				set_signal_status(effect, MAYBE_DIRTY);
-			}
+	for (const effect of eager_effects) {
+		// Mark clean inspect-effects as maybe dirty and then check their dirtiness
+		// instead of just updating the effects - this way we avoid overfiring.
+		if ((effect.f & CLEAN) !== 0) {
+			set_signal_status(effect, MAYBE_DIRTY);
+		}
 
-			if (is_dirty(effect)) {
-				update_effect(effect);
-			}
+		if (is_dirty(effect)) {
+			update_effect(effect);
 		}
-	} finally {
-		set_is_updating_effect(prev_is_updating_effect);
 	}
 
 	eager_effects.clear();
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 6988c6247a..19b98d0c0f 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -43,25 +43,14 @@ import {
 	set_dev_current_component_function,
 	set_dev_stack
 } from './context.js';
-import {
-	Batch,
-	batch_values,
-	current_batch,
-	flushSync,
-	schedule_effect
-} from './reactivity/batch.js';
+import { Batch, batch_values, flushSync, schedule_effect } from './reactivity/batch.js';
 import { handle_error } from './error-handling.js';
 import { UNINITIALIZED } from '../../constants.js';
 import { captured_signals } from './legacy.js';
 import { without_reactive_context } from './dom/elements/bindings/shared.js';
 import { set_signal_status, update_derived_status } from './reactivity/status.js';
 
-export let is_updating_effect = false;
-
-/** @param {boolean} value */
-export function set_is_updating_effect(value) {
-	is_updating_effect = value;
-}
+let is_updating_effect = false;
 
 export let is_destroying_effect = false;
 

From ac03d27d6872501fa2db836d9a92a47c3b5bbed6 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Thu, 22 Jan 2026 22:13:06 -0500
Subject: [PATCH 060/142] chore: reduce indirection, simplify logic in
 batch.process(...) (#17521)

* chore: reduce indirection, simplify logic in batch.process(...)

* this is unnecessary, previous_batch is only read in specific effects that run later
---
 .../src/internal/client/reactivity/batch.js   | 26 ++++++-------------
 1 file changed, 8 insertions(+), 18 deletions(-)

diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 5a041f9703..3c510f81d4 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -149,8 +149,6 @@ export class Batch {
 	process(root_effects) {
 		queued_root_effects = [];
 
-		previous_batch = null;
-
 		this.apply();
 
 		/** @type {Effect[]} */
@@ -168,14 +166,18 @@ export class Batch {
 			// log_inconsistent_branches(root);
 		}
 
-		if (!this.is_fork) {
-			this.#resolve();
-		}
-
 		if (this.is_deferred()) {
 			this.#defer_effects(render_effects);
 			this.#defer_effects(effects);
 		} else {
+			// append/remove branches
+			for (const fn of this.#commit_callbacks) fn();
+			this.#commit_callbacks.clear();
+
+			if (this.#pending === 0) {
+				this.#commit();
+			}
+
 			// If sources are written to, then work needs to happen in a separate batch, else prior sources would be mixed with
 			// newly updated sources, which could lead to infinite loops when effects run over and over again.
 			previous_batch = this;
@@ -328,18 +330,6 @@ export class Batch {
 		this.#discard_callbacks.clear();
 	}
 
-	#resolve() {
-		if (this.#blocking_pending === 0) {
-			// append/remove branches
-			for (const fn of this.#commit_callbacks) fn();
-			this.#commit_callbacks.clear();
-		}
-
-		if (this.#pending === 0) {
-			this.#commit();
-		}
-	}
-
 	#commit() {
 		// If there are other pending batches, they now need to be 'rebased' —
 		// in other words, we re-run block/async effects with the newly

From 1ff7dd6123e4a8d79e0f8336a24cc2db53aaa79c Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 23 Jan 2026 15:10:54 -0500
Subject: [PATCH 061/142] fix: batch resolution of async work (#17511)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* fix: batch resolution of async work

Co-authored-by: David Roizenman <hmnd@users.noreply.github.com>

* fix

* drive-by tidy up — Batch.enqueue is (apparently?) a useless wrapper around queue_micro_task

* 99% sure it's impossible for is_flushing to be true inside a queued task

* add some comments

* return early, reduce indentation

---------

Co-authored-by: David Roizenman <hmnd@users.noreply.github.com>
---
 .changeset/four-signs-listen.md               |  5 ++++
 .../internal/client/dom/blocks/boundary.js    | 20 +++++++++-----
 .../src/internal/client/reactivity/batch.js   | 26 ++++++++++++++-----
 3 files changed, 37 insertions(+), 14 deletions(-)
 create mode 100644 .changeset/four-signs-listen.md

diff --git a/.changeset/four-signs-listen.md b/.changeset/four-signs-listen.md
new file mode 100644
index 0000000000..b9e089fd12
--- /dev/null
+++ b/.changeset/four-signs-listen.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: batch resolution of async work
diff --git a/packages/svelte/src/internal/client/dom/blocks/boundary.js b/packages/svelte/src/internal/client/dom/blocks/boundary.js
index 61262a6576..90a695551a 100644
--- a/packages/svelte/src/internal/client/dom/blocks/boundary.js
+++ b/packages/svelte/src/internal/client/dom/blocks/boundary.js
@@ -102,6 +102,7 @@ export class Boundary {
 
 	#local_pending_count = 0;
 	#pending_count = 0;
+	#pending_count_update_queued = false;
 
 	#is_creating_fallback = false;
 
@@ -202,12 +203,11 @@ export class Boundary {
 
 	#hydrate_pending_content() {
 		const pending = this.#props.pending;
-		if (!pending) {
-			return;
-		}
+		if (!pending) return;
+
 		this.#pending_effect = branch(() => pending(this.#anchor));
 
-		Batch.enqueue(() => {
+		queue_micro_task(() => {
 			var anchor = this.#get_anchor();
 
 			this.#main_effect = this.#run(() => {
@@ -359,9 +359,15 @@ export class Boundary {
 
 		this.#local_pending_count += d;
 
-		if (this.#effect_pending) {
-			internal_set(this.#effect_pending, this.#local_pending_count);
-		}
+		if (!this.#effect_pending || this.#pending_count_update_queued) return;
+		this.#pending_count_update_queued = true;
+
+		queue_micro_task(() => {
+			this.#pending_count_update_queued = false;
+			if (this.#effect_pending) {
+				internal_set(this.#effect_pending, this.#local_pending_count);
+			}
+		});
 	}
 
 	get_effect_pending() {
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 3c510f81d4..c4caf8a20b 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -138,6 +138,8 @@ export class Batch {
 
 	is_fork = false;
 
+	#decrement_queued = false;
+
 	is_deferred() {
 		return this.is_fork || this.#blocking_pending > 0;
 	}
@@ -426,7 +428,22 @@ export class Batch {
 		this.#pending -= 1;
 		if (blocking) this.#blocking_pending -= 1;
 
-		this.revive();
+		if (this.#decrement_queued) return;
+		this.#decrement_queued = true;
+
+		queue_micro_task(() => {
+			this.#decrement_queued = false;
+
+			if (!this.is_deferred()) {
+				// we only reschedule previously-deferred effects if we expect
+				// to be able to run them after processing the batch
+				this.revive();
+			} else if (queued_root_effects.length > 0) {
+				// if other effects are scheduled, process the batch _without_
+				// rescheduling the previously-deferred effects
+				this.flush();
+			}
+		});
 	}
 
 	revive() {
@@ -464,7 +481,7 @@ export class Batch {
 			batches.add(current_batch);
 
 			if (!is_flushing_sync) {
-				Batch.enqueue(() => {
+				queue_micro_task(() => {
 					if (current_batch !== batch) {
 						// a flushSync happened in the meantime
 						return;
@@ -478,11 +495,6 @@ export class Batch {
 		return current_batch;
 	}
 
-	/** @param {() => void} task */
-	static enqueue(task) {
-		queue_micro_task(task);
-	}
-
 	apply() {
 		if (!async_mode_flag || (!this.is_fork && batches.size === 1)) return;
 

From 917ea2d4aea9e6a9da9cf0c5b4affa837097b4b5 Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Fri, 23 Jan 2026 22:43:31 +0100
Subject: [PATCH 062/142] fix: account for empty statements when visiting in
 transform async (#17524)

---
 .changeset/kind-dolls-cry.md                  |  5 ++++
 .../3-transform/shared/transform-async.js     | 27 ++++++++++---------
 .../_config.js                                |  5 ++++
 .../main.svelte                               |  6 +++++
 4 files changed, 31 insertions(+), 12 deletions(-)
 create mode 100644 .changeset/kind-dolls-cry.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-transform-empty-statements/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-transform-empty-statements/main.svelte

diff --git a/.changeset/kind-dolls-cry.md b/.changeset/kind-dolls-cry.md
new file mode 100644
index 0000000000..c6653d2f7f
--- /dev/null
+++ b/.changeset/kind-dolls-cry.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: account for empty statements when visiting in transform async
diff --git a/packages/svelte/src/compiler/phases/3-transform/shared/transform-async.js b/packages/svelte/src/compiler/phases/3-transform/shared/transform-async.js
index 8d3a6b2769..95b9f585d3 100644
--- a/packages/svelte/src/compiler/phases/3-transform/shared/transform-async.js
+++ b/packages/svelte/src/compiler/phases/3-transform/shared/transform-async.js
@@ -49,22 +49,25 @@ export function transform_body(instance_body, runner, transform) {
 	if (instance_body.async.length > 0) {
 		const thunks = instance_body.async.map((s) => {
 			if (s.node.type === 'VariableDeclarator') {
-				const visited = /** @type {ESTree.VariableDeclaration} */ (
+				const visited = /** @type {ESTree.VariableDeclaration | ESTree.EmptyStatement} */ (
 					transform(b.var(s.node.id, s.node.init))
 				);
 
-				const statements = visited.declarations.map((node) => {
-					if (
-						node.id.type === 'Identifier' &&
-						(node.id.name.startsWith('$$d') || node.id.name.startsWith('$$array'))
-					) {
-						// this is an intermediate declaration created in VariableDeclaration.js;
-						// subsequent statements depend on it
-						return b.var(node.id, node.init);
-					}
+				const statements =
+					visited.type === 'VariableDeclaration'
+						? visited.declarations.map((node) => {
+								if (
+									node.id.type === 'Identifier' &&
+									(node.id.name.startsWith('$$d') || node.id.name.startsWith('$$array'))
+								) {
+									// this is an intermediate declaration created in VariableDeclaration.js;
+									// subsequent statements depend on it
+									return b.var(node.id, node.init);
+								}
 
-					return b.stmt(b.assignment('=', node.id, node.init ?? b.void0));
-				});
+								return b.stmt(b.assignment('=', node.id, node.init ?? b.void0));
+							})
+						: [];
 
 				if (statements.length === 1) {
 					const statement = /** @type {ESTree.ExpressionStatement} */ (statements[0]);
diff --git a/packages/svelte/tests/runtime-runes/samples/async-transform-empty-statements/_config.js b/packages/svelte/tests/runtime-runes/samples/async-transform-empty-statements/_config.js
new file mode 100644
index 0000000000..2e4a27cf09
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-transform-empty-statements/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	async test() {}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-transform-empty-statements/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-transform-empty-statements/main.svelte
new file mode 100644
index 0000000000..03c4ada55a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-transform-empty-statements/main.svelte
@@ -0,0 +1,6 @@
+<script>
+	await Promise.resolve(42);
+	const { name } = $props();
+</script>
+
+{name}
\ No newline at end of file

From 319ceae20eb5655adde754daad5b4272952fbd0d Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Fri, 23 Jan 2026 23:05:07 +0100
Subject: [PATCH 063/142] chore: robustify some scripts (#17491)

* chore: robustify some scripts

- make it possible to call them with any cwd
- add ability to create test while downloading playground

* use parseArgs

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 playgrounds/sandbox/scripts/create-test.js | 22 ++++--
 playgrounds/sandbox/scripts/download.js    | 78 ++++++++++++++++++++--
 2 files changed, 88 insertions(+), 12 deletions(-)

diff --git a/playgrounds/sandbox/scripts/create-test.js b/playgrounds/sandbox/scripts/create-test.js
index c733f19419..d183098b22 100644
--- a/playgrounds/sandbox/scripts/create-test.js
+++ b/playgrounds/sandbox/scripts/create-test.js
@@ -1,6 +1,16 @@
-// Creates a test from the existing playground. cwd needs to be playground/sandbox
+// Creates a test from the existing playground. Can be called from anywhere.
 import fs from 'fs';
 import path from 'path';
+import { fileURLToPath } from 'url';
+
+// Get the directory where this script is located
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+// Base paths relative to this script's location
+const sandbox_dir = path.resolve(__dirname, '..');
+const src_dir = path.join(sandbox_dir, 'src');
+const tests_dir = path.resolve(__dirname, '../../../packages/svelte/tests');
 
 // Get target folder from command line arguments
 let target_folder = process.argv[2];
@@ -20,7 +30,7 @@ if (!target_folder.startsWith('runtime-')) {
 	process.exit(1);
 }
 target_folder = path.join(
-	path.resolve('../../packages/svelte/tests', target_folder.split('/')[0]),
+	path.resolve(tests_dir, target_folder.split('/')[0]),
 	'samples',
 	target_folder.split('/')[1]
 );
@@ -56,8 +66,8 @@ if (exists) {
 	const files = fs.readdirSync(target_folder);
 	for (const file of files) {
 		if (file !== '_config.js') {
-			const filePath = path.join(target_folder, file);
-			fs.rmSync(filePath, { recursive: true, force: true });
+			const file_path = path.join(target_folder, file);
+			fs.rmSync(file_path, { recursive: true, force: true });
 		}
 	}
 } else {
@@ -65,7 +75,7 @@ if (exists) {
 }
 
 // Starting file
-const app_svelte_path = path.resolve('./src/App.svelte');
+const app_svelte_path = path.join(src_dir, 'App.svelte');
 const collected_files = new Set();
 const processed_files = new Set();
 
@@ -117,7 +127,7 @@ collect_imports(app_svelte_path);
 
 // Copy collected files to target folder
 for (const file_path of collected_files) {
-	const relative_path = path.relative(path.resolve('./src'), file_path);
+	const relative_path = path.relative(src_dir, file_path);
 	let target_path = path.join(target_folder, relative_path);
 
 	// Rename App.svelte to main.svelte
diff --git a/playgrounds/sandbox/scripts/download.js b/playgrounds/sandbox/scripts/download.js
index 5678f69ee3..b5eaeaa8f5 100644
--- a/playgrounds/sandbox/scripts/download.js
+++ b/playgrounds/sandbox/scripts/download.js
@@ -1,19 +1,36 @@
 import fs from 'node:fs';
+import path from 'node:path';
+import { parseArgs } from 'node:util';
 
-const arg = process.argv[2];
+const { values, positionals } = parseArgs({
+	options: {
+		'create-test': {
+			type: 'string'
+		}
+	},
+	allowPositionals: true
+});
+
+const create_test_name = values['create-test'] ?? null;
+const url_arg = positionals[0];
+
+if (!url_arg) {
+	console.error(`Missing URL argument`);
+	process.exit(1);
+}
 
 /** @type {URL} */
 let url;
 
 try {
-	url = new URL(arg);
+	url = new URL(url_arg);
 } catch (e) {
-	console.error(`${arg} is not a URL`);
+	console.error(`${url_arg} is not a URL`);
 	process.exit(1);
 }
 
 if (url.origin !== 'https://svelte.dev' || !url.pathname.startsWith('/playground/')) {
-	console.error(`${arg} is not a Svelte playground URL`);
+	console.error(`${url_arg} is not a Svelte playground URL`);
 	process.exit(1);
 }
 
@@ -47,6 +64,55 @@ if (url.hash.length > 1) {
 	});
 }
 
-for (const file of files) {
-	fs.writeFileSync(`src/${file.name}`, file.contents);
+const base_dir = import.meta.dirname;
+
+if (create_test_name) {
+	const test_parts = create_test_name.split('/').filter(Boolean);
+
+	if (test_parts.length > 2) {
+		console.error(
+			`Invalid test name "${create_test_name}". Expected e.g. "hello-world" or "runtime-legacy/hello-world"`
+		);
+		process.exit(1);
+	}
+
+	const suite_name = test_parts.length === 2 ? test_parts[0] : 'runtime-runes';
+	const test_name = test_parts[test_parts.length - 1];
+
+	const output_dir = path.join(
+		base_dir,
+		'../../..',
+		'packages/svelte/tests',
+		suite_name,
+		'samples',
+		test_name
+	);
+	if (fs.existsSync(output_dir)) {
+		console.warn(`Test folder "${output_dir}" already exists, overriding its contents`);
+		fs.rmSync(output_dir, { recursive: true, force: true });
+	}
+	fs.mkdirSync(output_dir, { recursive: true });
+
+	for (const file of files) {
+		const output_name = file.name === 'App.svelte' ? 'main.svelte' : file.name;
+		const output_path = path.join(output_dir, output_name);
+
+		fs.mkdirSync(path.dirname(output_path), { recursive: true });
+		fs.writeFileSync(output_path, file.contents);
+	}
+
+	fs.writeFileSync(
+		path.join(output_dir, '_config.js'),
+		`import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+	}
+});
+`
+	);
+} else {
+	for (const file of files) {
+		fs.writeFileSync(path.join(base_dir, '..', 'src', file.name), file.contents);
+	}
 }

From 7ab62a5878b5452fbc222a1f1a6adc9c424501d0 Mon Sep 17 00:00:00 2001
From: Pooh <thanadolps@gmail.com>
Date: Sat, 24 Jan 2026 05:05:30 +0700
Subject: [PATCH 064/142] docs: fix <svelte:boundary> tag in
 const_tag_invalid_placement message (#17501)

Co-authored-by: Thanadol Chitthamlerd <tchitthamlerd@smartertravel.com>
---
 documentation/docs/98-reference/.generated/compile-errors.md  | 2 +-
 packages/svelte/messages/compile-errors/template.md           | 2 +-
 packages/svelte/src/compiler/errors.js                        | 4 ++--
 .../tests/validator/samples/const-tag-placement-1/errors.json | 2 +-
 .../tests/validator/samples/const-tag-placement-2/errors.json | 2 +-
 5 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/documentation/docs/98-reference/.generated/compile-errors.md b/documentation/docs/98-reference/.generated/compile-errors.md
index 8a8a10c80b..ff452cc674 100644
--- a/documentation/docs/98-reference/.generated/compile-errors.md
+++ b/documentation/docs/98-reference/.generated/compile-errors.md
@@ -193,7 +193,7 @@ Cyclical dependency detected: %cycle%
 ### const_tag_invalid_placement
 
 ```
-`{@const}` must be the immediate child of `{#snippet}`, `{#if}`, `{:else if}`, `{:else}`, `{#each}`, `{:then}`, `{:catch}`, `<svelte:fragment>`, `<svelte:boundary` or `<Component>`
+`{@const}` must be the immediate child of `{#snippet}`, `{#if}`, `{:else if}`, `{:else}`, `{#each}`, `{:then}`, `{:catch}`, `<svelte:fragment>`, `<svelte:boundary>` or `<Component>`
 ```
 
 ### const_tag_invalid_reference
diff --git a/packages/svelte/messages/compile-errors/template.md b/packages/svelte/messages/compile-errors/template.md
index db23a2eaa8..086b9e8b25 100644
--- a/packages/svelte/messages/compile-errors/template.md
+++ b/packages/svelte/messages/compile-errors/template.md
@@ -122,7 +122,7 @@
 
 ## const_tag_invalid_placement
 
-> `{@const}` must be the immediate child of `{#snippet}`, `{#if}`, `{:else if}`, `{:else}`, `{#each}`, `{:then}`, `{:catch}`, `<svelte:fragment>`, `<svelte:boundary` or `<Component>`
+> `{@const}` must be the immediate child of `{#snippet}`, `{#if}`, `{:else if}`, `{:else}`, `{#each}`, `{:then}`, `{:catch}`, `<svelte:fragment>`, `<svelte:boundary>` or `<Component>`
 
 ## const_tag_invalid_reference
 
diff --git a/packages/svelte/src/compiler/errors.js b/packages/svelte/src/compiler/errors.js
index d6c2efdfdc..990b643e68 100644
--- a/packages/svelte/src/compiler/errors.js
+++ b/packages/svelte/src/compiler/errors.js
@@ -977,12 +977,12 @@ export function const_tag_invalid_expression(node) {
 }
 
 /**
- * `{@const}` must be the immediate child of `{#snippet}`, `{#if}`, `{:else if}`, `{:else}`, `{#each}`, `{:then}`, `{:catch}`, `<svelte:fragment>`, `<svelte:boundary` or `<Component>`
+ * `{@const}` must be the immediate child of `{#snippet}`, `{#if}`, `{:else if}`, `{:else}`, `{#each}`, `{:then}`, `{:catch}`, `<svelte:fragment>`, `<svelte:boundary>` or `<Component>`
  * @param {null | number | NodeLike} node
  * @returns {never}
  */
 export function const_tag_invalid_placement(node) {
-	e(node, 'const_tag_invalid_placement', `\`{@const}\` must be the immediate child of \`{#snippet}\`, \`{#if}\`, \`{:else if}\`, \`{:else}\`, \`{#each}\`, \`{:then}\`, \`{:catch}\`, \`<svelte:fragment>\`, \`<svelte:boundary\` or \`<Component>\`\nhttps://svelte.dev/e/const_tag_invalid_placement`);
+	e(node, 'const_tag_invalid_placement', `\`{@const}\` must be the immediate child of \`{#snippet}\`, \`{#if}\`, \`{:else if}\`, \`{:else}\`, \`{#each}\`, \`{:then}\`, \`{:catch}\`, \`<svelte:fragment>\`, \`<svelte:boundary>\` or \`<Component>\`\nhttps://svelte.dev/e/const_tag_invalid_placement`);
 }
 
 /**
diff --git a/packages/svelte/tests/validator/samples/const-tag-placement-1/errors.json b/packages/svelte/tests/validator/samples/const-tag-placement-1/errors.json
index 514e5d0561..f7f5803e74 100644
--- a/packages/svelte/tests/validator/samples/const-tag-placement-1/errors.json
+++ b/packages/svelte/tests/validator/samples/const-tag-placement-1/errors.json
@@ -1,7 +1,7 @@
 [
 	{
 		"code": "const_tag_invalid_placement",
-		"message": "`{@const}` must be the immediate child of `{#snippet}`, `{#if}`, `{:else if}`, `{:else}`, `{#each}`, `{:then}`, `{:catch}`, `<svelte:fragment>`, `<svelte:boundary` or `<Component>`",
+		"message": "`{@const}` must be the immediate child of `{#snippet}`, `{#if}`, `{:else if}`, `{:else}`, `{#each}`, `{:then}`, `{:catch}`, `<svelte:fragment>`, `<svelte:boundary>` or `<Component>`",
 		"start": {
 			"line": 5,
 			"column": 0
diff --git a/packages/svelte/tests/validator/samples/const-tag-placement-2/errors.json b/packages/svelte/tests/validator/samples/const-tag-placement-2/errors.json
index 6b968f7eda..d008c6ce4c 100644
--- a/packages/svelte/tests/validator/samples/const-tag-placement-2/errors.json
+++ b/packages/svelte/tests/validator/samples/const-tag-placement-2/errors.json
@@ -1,7 +1,7 @@
 [
 	{
 		"code": "const_tag_invalid_placement",
-		"message": "`{@const}` must be the immediate child of `{#snippet}`, `{#if}`, `{:else if}`, `{:else}`, `{#each}`, `{:then}`, `{:catch}`, `<svelte:fragment>`, `<svelte:boundary` or `<Component>`",
+		"message": "`{@const}` must be the immediate child of `{#snippet}`, `{#if}`, `{:else if}`, `{:else}`, `{#each}`, `{:then}`, `{:catch}`, `<svelte:fragment>`, `<svelte:boundary>` or `<Component>`",
 		"start": {
 			"line": 7,
 			"column": 4

From 9b6539a8ef2483d9090e48d5ce0f33ae01b82cfd Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 23 Jan 2026 17:08:09 -0500
Subject: [PATCH 065/142] fix: properly hydrate await in `{@html}`
 (alternative) (#17528)

* fix: properly hydrate await in `{@html}`

* fix: skip no async

* revert runtime changes

* wrap html blocks in hydration comments

* prettier

---------

Co-authored-by: paoloricciuti <ricciutipaolo@gmail.com>
---
 .changeset/bright-pants-send.md                      |  5 +++++
 .../phases/3-transform/server/visitors/HtmlTag.js    | 12 +++++++++++-
 .../samples/await-html-hydration/_config.js          |  7 +++++++
 .../samples/await-html-hydration/main.svelte         |  1 +
 4 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/bright-pants-send.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/await-html-hydration/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/await-html-hydration/main.svelte

diff --git a/.changeset/bright-pants-send.md b/.changeset/bright-pants-send.md
new file mode 100644
index 0000000000..8a877961ec
--- /dev/null
+++ b/.changeset/bright-pants-send.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: properly hydrate await in `{@html}`
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/HtmlTag.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/HtmlTag.js
index 08fd2133ee..3f423fa60d 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/HtmlTag.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/HtmlTag.js
@@ -2,7 +2,7 @@
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types.js' */
 import * as b from '#compiler/builders';
-import { create_push } from './shared/utils.js';
+import { block_close, block_open, create_push } from './shared/utils.js';
 
 /**
  * @param {AST.HtmlTag} node
@@ -12,5 +12,15 @@ export function HtmlTag(node, context) {
 	const expression = /** @type {Expression} */ (context.visit(node.expression));
 	const call = b.call('$.html', expression);
 
+	const has_await = node.metadata.expression.has_await;
+
+	if (has_await) {
+		context.state.template.push(block_open);
+	}
+
 	context.state.template.push(create_push(call, node.metadata.expression, true));
+
+	if (has_await) {
+		context.state.template.push(block_close);
+	}
 }
diff --git a/packages/svelte/tests/runtime-runes/samples/await-html-hydration/_config.js b/packages/svelte/tests/runtime-runes/samples/await-html-hydration/_config.js
new file mode 100644
index 0000000000..e7983a3de9
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/await-html-hydration/_config.js
@@ -0,0 +1,7 @@
+import { test } from '../../test';
+
+export default test({
+	skip_no_async: true,
+	mode: ['hydrate'],
+	async test() {}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/await-html-hydration/main.svelte b/packages/svelte/tests/runtime-runes/samples/await-html-hydration/main.svelte
new file mode 100644
index 0000000000..3b9ce94e61
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/await-html-hydration/main.svelte
@@ -0,0 +1 @@
+<div>{@html await Promise.resolve(`<span>Foo</span>`)}</div>
\ No newline at end of file

From 0f68a00c3c3203062bb5f99bc5362beeb816dcff Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 23 Jan 2026 17:09:12 -0500
Subject: [PATCH 066/142] chore: defense-in-depth against script escapes
 (#17479)

* chore: defense-in-depth against script escapes

* Update packages/svelte/src/internal/server/dev.js
---
 packages/svelte/src/internal/server/dev.js | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/packages/svelte/src/internal/server/dev.js b/packages/svelte/src/internal/server/dev.js
index 4a6cdb8cf6..e953bac6ce 100644
--- a/packages/svelte/src/internal/server/dev.js
+++ b/packages/svelte/src/internal/server/dev.js
@@ -40,7 +40,12 @@ function print_error(renderer, message) {
 
 	// eslint-disable-next-line no-console
 	console.error(message);
-	renderer.head((r) => r.push(`<script>console.error(${JSON.stringify(message)})</script>`));
+	renderer.head((r) =>
+		r.push(
+			// ensure that `</script>` can't leak in to the script contents
+			`<script>console.error(${JSON.stringify(message).replaceAll('</', '<\\u002f')})</script>`
+		)
+	);
 }
 
 /**

From 9108404450cb75da65e8588fdc4f29743979bc02 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Fri, 23 Jan 2026 23:53:00 -0500
Subject: [PATCH 067/142] Version Packages (#17517)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/blue-parts-double.md   |  5 -----
 .changeset/bright-pants-send.md   |  5 -----
 .changeset/four-signs-listen.md   |  5 -----
 .changeset/kind-dolls-cry.md      |  5 -----
 .changeset/ten-horses-cross.md    |  5 -----
 .changeset/witty-streets-carry.md |  5 -----
 packages/svelte/CHANGELOG.md      | 16 ++++++++++++++++
 packages/svelte/package.json      |  2 +-
 packages/svelte/src/version.js    |  2 +-
 9 files changed, 18 insertions(+), 32 deletions(-)
 delete mode 100644 .changeset/blue-parts-double.md
 delete mode 100644 .changeset/bright-pants-send.md
 delete mode 100644 .changeset/four-signs-listen.md
 delete mode 100644 .changeset/kind-dolls-cry.md
 delete mode 100644 .changeset/ten-horses-cross.md
 delete mode 100644 .changeset/witty-streets-carry.md

diff --git a/.changeset/blue-parts-double.md b/.changeset/blue-parts-double.md
deleted file mode 100644
index 223e51fdae..0000000000
--- a/.changeset/blue-parts-double.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: hoist snippets above const in same block
diff --git a/.changeset/bright-pants-send.md b/.changeset/bright-pants-send.md
deleted file mode 100644
index 8a877961ec..0000000000
--- a/.changeset/bright-pants-send.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: properly hydrate await in `{@html}`
diff --git a/.changeset/four-signs-listen.md b/.changeset/four-signs-listen.md
deleted file mode 100644
index b9e089fd12..0000000000
--- a/.changeset/four-signs-listen.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: batch resolution of async work
diff --git a/.changeset/kind-dolls-cry.md b/.changeset/kind-dolls-cry.md
deleted file mode 100644
index c6653d2f7f..0000000000
--- a/.changeset/kind-dolls-cry.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: account for empty statements when visiting in transform async
diff --git a/.changeset/ten-horses-cross.md b/.changeset/ten-horses-cross.md
deleted file mode 100644
index 5502c5887b..0000000000
--- a/.changeset/ten-horses-cross.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: avoid async overhead for already settled promises
diff --git a/.changeset/witty-streets-carry.md b/.changeset/witty-streets-carry.md
deleted file mode 100644
index f02d998409..0000000000
--- a/.changeset/witty-streets-carry.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: better code generation for const tags with async dependencies
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 21cbb4ee66..d9b67e08a3 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,21 @@
 # svelte
 
+## 5.48.1
+
+### Patch Changes
+
+- fix: hoist snippets above const in same block ([#17516](https://github.com/sveltejs/svelte/pull/17516))
+
+- fix: properly hydrate await in `{@html}` ([#17528](https://github.com/sveltejs/svelte/pull/17528))
+
+- fix: batch resolution of async work ([#17511](https://github.com/sveltejs/svelte/pull/17511))
+
+- fix: account for empty statements when visiting in transform async ([#17524](https://github.com/sveltejs/svelte/pull/17524))
+
+- fix: avoid async overhead for already settled promises ([#17461](https://github.com/sveltejs/svelte/pull/17461))
+
+- fix: better code generation for const tags with async dependencies ([#17518](https://github.com/sveltejs/svelte/pull/17518))
+
 ## 5.48.0
 
 ### Minor Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index bbb519f8e8..d4d7aef12b 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": "5.48.0",
+  "version": "5.48.1",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index c1ced8dad3..88ffc1f497 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 = '5.48.0';
+export const VERSION = '5.48.1';
 export const PUBLIC_VERSION = '5';

From 6046bbb4564cc3cc44332313a6293cf06f148227 Mon Sep 17 00:00:00 2001
From: Benjamin Tamasi <half2me@users.noreply.github.com>
Date: Sat, 24 Jan 2026 15:37:04 +0100
Subject: [PATCH 068/142] fix: export `wait` function from internal client
 index (#17530)

PR #17461 added the `wait` function to `reactivity/async.js` and modified the compiler to generate `$.wait()` calls, but forgot to export it from `index.js`.

This causes a runtime error when using `await` inside `$derived()` with `experimental.async: true`:

```
TypeError: $.wait is not a function
```

Fixes #17529
---
 .changeset/fix-wait-export.md                  |  5 +++++
 packages/svelte/src/internal/client/index.js   |  3 ++-
 .../samples/async-const-wait/_config.js        | 18 ++++++++++++++++++
 .../samples/async-const-wait/main.svelte       | 16 ++++++++++++++++
 4 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/fix-wait-export.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-const-wait/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-const-wait/main.svelte

diff --git a/.changeset/fix-wait-export.md b/.changeset/fix-wait-export.md
new file mode 100644
index 0000000000..e0ab97207c
--- /dev/null
+++ b/.changeset/fix-wait-export.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: export `wait` function from internal client index
diff --git a/packages/svelte/src/internal/client/index.js b/packages/svelte/src/internal/client/index.js
index 0f20ce300d..1d9f7dfff7 100644
--- a/packages/svelte/src/internal/client/index.js
+++ b/packages/svelte/src/internal/client/index.js
@@ -103,7 +103,8 @@ export {
 	run,
 	save,
 	track_reactivity_loss,
-	run_after_blockers
+	run_after_blockers,
+	wait
 } from './reactivity/async.js';
 export { eager, flushSync as flush } from './reactivity/batch.js';
 export {
diff --git a/packages/svelte/tests/runtime-runes/samples/async-const-wait/_config.js b/packages/svelte/tests/runtime-runes/samples/async-const-wait/_config.js
new file mode 100644
index 0000000000..fe85c0393a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-const-wait/_config.js
@@ -0,0 +1,18 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['client'],
+
+	props: {
+		a_promise: Promise.resolve(10),
+		b_promise: Promise.resolve(20)
+	},
+
+	async test({ assert, target }) {
+		await tick();
+		await tick();
+
+		assert.htmlEqual(target.innerHTML, `<p>30</p>`);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-const-wait/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-const-wait/main.svelte
new file mode 100644
index 0000000000..b5e6d90f7c
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-const-wait/main.svelte
@@ -0,0 +1,16 @@
+<script>
+	let { a_promise, b_promise } = $props();
+</script>
+
+<svelte:boundary>
+	{@const a = await a_promise}
+	{#if true}
+		<svelte:boundary>
+			{@const b = await b_promise}
+			{#if true}
+				{@const sum = a + b}
+				<p>{sum}</p>
+			{/if}
+		</svelte:boundary>
+	{/if}
+</svelte:boundary>

From e1427aa0c8b5abe88aea972ea397ea499cb8f2db Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Sat, 24 Jan 2026 15:43:54 +0100
Subject: [PATCH 069/142] Version Packages (#17531)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/fix-wait-export.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/fix-wait-export.md

diff --git a/.changeset/fix-wait-export.md b/.changeset/fix-wait-export.md
deleted file mode 100644
index e0ab97207c..0000000000
--- a/.changeset/fix-wait-export.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: export `wait` function from internal client index
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index d9b67e08a3..e619f55654 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,11 @@
 # svelte
 
+## 5.48.2
+
+### Patch Changes
+
+- fix: export `wait` function from internal client index ([#17530](https://github.com/sveltejs/svelte/pull/17530))
+
 ## 5.48.1
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index d4d7aef12b..7763aba87e 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": "5.48.1",
+  "version": "5.48.2",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 88ffc1f497..2b30052317 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 = '5.48.1';
+export const VERSION = '5.48.2';
 export const PUBLIC_VERSION = '5';

From fe12ffc2a3ebfb4fcf43f283fccb984363c1ea84 Mon Sep 17 00:00:00 2001
From: David <david@hmnd.io>
Date: Sun, 25 Jan 2026 07:16:45 -0800
Subject: [PATCH 070/142] fix: avoid unnecessary block effect re-runs after
 async work completes (#17535)

* add samples for async readable freeze

* test updating without changing reference too

* fix: treat block effects as maybe dirty in revive()

* even simpler - put block effects in maybe_dirty_effects

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/wise-emus-hunt.md                  |  5 +++
 .../src/internal/client/reactivity/batch.js   |  2 +-
 .../async-await-store-mutate/_config.js       | 24 ++++++++++++++
 .../async-await-store-mutate/main.svelte      | 26 +++++++++++++++
 .../async-each-await-store-update/_config.js  | 32 +++++++++++++++++++
 .../async-each-await-store-update/main.svelte | 31 ++++++++++++++++++
 6 files changed, 119 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/wise-emus-hunt.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-await-store-mutate/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-await-store-mutate/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-each-await-store-update/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-each-await-store-update/main.svelte

diff --git a/.changeset/wise-emus-hunt.md b/.changeset/wise-emus-hunt.md
new file mode 100644
index 0000000000..c8b3f93de8
--- /dev/null
+++ b/.changeset/wise-emus-hunt.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: avoid unnecessary block effect re-runs after async work completes
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index c4caf8a20b..5647c08ba5 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -243,7 +243,7 @@ export class Batch {
 				} else if (async_mode_flag && (flags & (RENDER_EFFECT | MANAGED_EFFECT)) !== 0) {
 					render_effects.push(effect);
 				} else if (is_dirty(effect)) {
-					if ((flags & BLOCK_EFFECT) !== 0) this.#dirty_effects.add(effect);
+					if ((flags & BLOCK_EFFECT) !== 0) this.#maybe_dirty_effects.add(effect);
 					update_effect(effect);
 				}
 
diff --git a/packages/svelte/tests/runtime-runes/samples/async-await-store-mutate/_config.js b/packages/svelte/tests/runtime-runes/samples/async-await-store-mutate/_config.js
new file mode 100644
index 0000000000..e89065865f
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-await-store-mutate/_config.js
@@ -0,0 +1,24 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+// ensure in-place object mutations stay reactive in async
+export default test({
+	skip_no_async: true,
+	async test({ assert, target }) {
+		const button = /** @type {HTMLElement} */ (target.querySelector('button'));
+
+		await tick();
+
+		assert.htmlEqual(target.innerHTML, `<p>count: 1, computed: 10</p><button>mutate</button>`);
+
+		button.click();
+		await tick();
+
+		assert.htmlEqual(target.innerHTML, `<p>count: 2, computed: 20</p><button>mutate</button>`);
+
+		button.click();
+		await tick();
+
+		assert.htmlEqual(target.innerHTML, `<p>count: 3, computed: 30</p><button>mutate</button>`);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-await-store-mutate/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-await-store-mutate/main.svelte
new file mode 100644
index 0000000000..327c775d6e
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-await-store-mutate/main.svelte
@@ -0,0 +1,26 @@
+<script>
+	import { writable } from 'svelte/store';
+
+	const data = writable({ count: 1 });
+
+	function mutate_count() {
+		data.update(d => {
+			d.count++;
+			return d;
+		});
+	}
+
+	async function compute(d) {
+		return Promise.resolve(d.count * 10);
+	}
+</script>
+
+<svelte:boundary>
+	<p>count: {$data.count}, computed: {await compute($data)}</p>
+
+	{#snippet pending()}
+		<p>pending</p>
+	{/snippet}
+</svelte:boundary>
+
+<button onclick={mutate_count}>mutate</button>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-each-await-store-update/_config.js b/packages/svelte/tests/runtime-runes/samples/async-each-await-store-update/_config.js
new file mode 100644
index 0000000000..165577af96
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-each-await-store-update/_config.js
@@ -0,0 +1,32 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	skip_no_async: true,
+	async test({ assert, target }) {
+		const button = /** @type {HTMLElement} */ (target.querySelector('button'));
+
+		await tick();
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`<ul><li data-item="1"><span>10</span><span>20</span></li></ul><button>add</button>`
+		);
+
+		button.click();
+		await tick();
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`<ul><li data-item="1"><span>10</span><span>20</span></li><li data-item="2"><span>20</span><span>40</span></li></ul><button>add</button>`
+		);
+
+		button.click();
+		await tick();
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`<ul><li data-item="1"><span>10</span><span>20</span></li><li data-item="2"><span>20</span><span>40</span></li><li data-item="3"><span>30</span><span>60</span></li></ul><button>add</button>`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-each-await-store-update/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-each-await-store-update/main.svelte
new file mode 100644
index 0000000000..41982b767d
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-each-await-store-update/main.svelte
@@ -0,0 +1,31 @@
+<script>
+	import { writable } from 'svelte/store';
+
+	const items = writable([{ id: 1 }]);
+
+	function add_item() {
+		items.update(arr => [...arr, { id: arr.length + 1 }]);
+	}
+
+	function query(item) {
+		return Promise.resolve([item.id * 10, item.id * 20]);
+	}
+</script>
+
+<svelte:boundary>
+	<ul>
+		{#each $items as item (item.id)}
+			<li data-item={item.id}>
+				{#each await query(item) as value}
+					<span>{value}</span>
+				{/each}
+			</li>
+		{/each}
+	</ul>
+	
+	{#snippet pending()}
+		<p>pending</p>
+	{/snippet}
+</svelte:boundary>
+
+<button onclick={add_item}>add</button>

From c041d122ba229695a77e4ac750d006ece1350347 Mon Sep 17 00:00:00 2001
From: Gokul <116172293+duraisamy-gokul@users.noreply.github.com>
Date: Sun, 25 Jan 2026 21:25:47 +0530
Subject: [PATCH 071/142] docs: add note about typing children as Snippet in
 $props (#17534)

* docs: add note about typing children as Snippet in \$props

* Apply suggestion from @Rich-Harris

* Apply suggestion from @Rich-Harris

---------

Co-authored-by: gokul.d <gokul.d@juspay.in>
Co-authored-by: Rich Harris <hello@rich-harris.dev>
---
 documentation/docs/02-runes/05-$props.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/documentation/docs/02-runes/05-$props.md b/documentation/docs/02-runes/05-$props.md
index 222b4831b6..bd5ae16853 100644
--- a/documentation/docs/02-runes/05-$props.md
+++ b/documentation/docs/02-runes/05-$props.md
@@ -198,6 +198,8 @@ You can, of course, separate the type declaration from the annotation:
 
 > [!NOTE] Interfaces for native DOM elements are provided in the `svelte/elements` module (see [Typing wrapper components](typescript#Typing-wrapper-components))
 
+If your component exposes [snippet](snippet) props like `children`, these should be typed using the `Snippet` interface imported from `'svelte'` — see [Typing snippets](snippet#Typing-snippets) for examples.
+
 Adding types is recommended, as it ensures that people using your component can easily discover which props they should provide.
 
 

From bec90d4801d81bd0b013540676d31ae0b90283f4 Mon Sep 17 00:00:00 2001
From: David <david@hmnd.io>
Date: Sun, 25 Jan 2026 07:56:14 -0800
Subject: [PATCH 072/142] fix: avoid using dev-mode array.includes wrapper on
 internal array checks (#17536)

* fix: avoid using dev-mode array.includes wrapper on internal array checks

* use includes rather than index_of

* unused imports

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/yellow-bobcats-hope.md                      |  5 +++++
 .../svelte/src/internal/client/reactivity/batch.js     |  4 ++--
 .../svelte/src/internal/client/reactivity/deriveds.js  |  4 ++--
 .../svelte/src/internal/client/reactivity/sources.js   |  3 ++-
 packages/svelte/src/internal/client/runtime.js         | 10 +++++-----
 packages/svelte/src/internal/shared/utils.js           |  1 +
 6 files changed, 17 insertions(+), 10 deletions(-)
 create mode 100644 .changeset/yellow-bobcats-hope.md

diff --git a/.changeset/yellow-bobcats-hope.md b/.changeset/yellow-bobcats-hope.md
new file mode 100644
index 0000000000..dffeea3177
--- /dev/null
+++ b/.changeset/yellow-bobcats-hope.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: avoid using dev-mode array.includes wrapper on internal array checks
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 5647c08ba5..134ebe53a2 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -21,7 +21,7 @@ import {
 	MANAGED_EFFECT
 } from '#client/constants';
 import { async_mode_flag } from '../../flags/index.js';
-import { deferred, define_property } from '../../shared/utils.js';
+import { deferred, define_property, includes } from '../../shared/utils.js';
 import {
 	active_effect,
 	get,
@@ -775,7 +775,7 @@ function depends_on(reaction, sources, checked) {
 
 	if (reaction.deps !== null) {
 		for (const dep of reaction.deps) {
-			if (sources.includes(dep)) {
+			if (includes.call(sources, dep)) {
 				return true;
 			}
 
diff --git a/packages/svelte/src/internal/client/reactivity/deriveds.js b/packages/svelte/src/internal/client/reactivity/deriveds.js
index 59fb0f15aa..bb732bdd1e 100644
--- a/packages/svelte/src/internal/client/reactivity/deriveds.js
+++ b/packages/svelte/src/internal/client/reactivity/deriveds.js
@@ -33,7 +33,7 @@ import { component_context } from '../context.js';
 import { UNINITIALIZED } from '../../../constants.js';
 import { batch_values, current_batch } from './batch.js';
 import { unset_context } from './async.js';
-import { deferred } from '../../shared/utils.js';
+import { deferred, includes } from '../../shared/utils.js';
 import { set_signal_status, update_derived_status } from './status.js';
 
 /** @type {Effect | null} */
@@ -322,7 +322,7 @@ export function execute_derived(derived) {
 		let prev_eager_effects = eager_effects;
 		set_eager_effects(new Set());
 		try {
-			if (stack.includes(derived)) {
+			if (includes.call(stack, derived)) {
 				e.derived_references_self();
 			}
 
diff --git a/packages/svelte/src/internal/client/reactivity/sources.js b/packages/svelte/src/internal/client/reactivity/sources.js
index 7604c9e90b..3ef08588c4 100644
--- a/packages/svelte/src/internal/client/reactivity/sources.js
+++ b/packages/svelte/src/internal/client/reactivity/sources.js
@@ -31,6 +31,7 @@ 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';
@@ -150,7 +151,7 @@ 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?.includes(source)
+		(current_sources === null || !includes.call(current_sources, source))
 	) {
 		e.state_unsafe_mutation();
 	}
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 19b98d0c0f..2075081f96 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -1,6 +1,6 @@
 /** @import { Derived, Effect, Reaction, Source, Value } from '#client' */
 import { DEV } from 'esm-env';
-import { get_descriptors, get_prototype_of, index_of } from '../shared/utils.js';
+import { get_descriptors, get_prototype_of, includes, index_of } from '../shared/utils.js';
 import {
 	destroy_block_effect_children,
 	destroy_effect_children,
@@ -192,7 +192,7 @@ function schedule_possible_effect_self_invalidation(signal, effect, root = true)
 	var reactions = signal.reactions;
 	if (reactions === null) return;
 
-	if (!async_mode_flag && current_sources?.includes(signal)) {
+	if (!async_mode_flag && current_sources !== null && includes.call(current_sources, signal)) {
 		return;
 	}
 
@@ -371,7 +371,7 @@ function remove_reaction(signal, dependency) {
 		// Destroying a child effect while updating a parent effect can cause a dependency to appear
 		// to be unused, when in fact it is used by the currently-updating parent. Checking `new_deps`
 		// allows us to skip the expensive work of disconnecting and immediately reconnecting it
-		(new_deps === null || !new_deps.includes(dependency))
+		(new_deps === null || !includes.call(new_deps, dependency))
 	) {
 		var derived = /** @type {Derived} */ (dependency);
 
@@ -514,7 +514,7 @@ 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?.includes(signal)) {
+		if (!destroyed && (current_sources === null || !includes.call(current_sources, signal))) {
 			var deps = active_reaction.deps;
 
 			if ((active_reaction.f & REACTION_IS_UPDATING) !== 0) {
@@ -542,7 +542,7 @@ export function get(signal) {
 
 				if (reactions === null) {
 					signal.reactions = [active_reaction];
-				} else if (!reactions.includes(active_reaction)) {
+				} else if (!includes.call(reactions, active_reaction)) {
 					reactions.push(active_reaction);
 				}
 			}
diff --git a/packages/svelte/src/internal/shared/utils.js b/packages/svelte/src/internal/shared/utils.js
index 659cd10040..771f6b345c 100644
--- a/packages/svelte/src/internal/shared/utils.js
+++ b/packages/svelte/src/internal/shared/utils.js
@@ -2,6 +2,7 @@
 // to de-opt (this occurs often when using popular extensions).
 export var is_array = Array.isArray;
 export var index_of = Array.prototype.indexOf;
+export var includes = Array.prototype.includes;
 export var array_from = Array.from;
 export var object_keys = Object.keys;
 export var define_property = Object.defineProperty;

From 6e4820dcf6a2f0bd6bfbd255ae86c7fe1da11705 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draic=20Slattery?= <pgoslatara@gmail.com>
Date: Sun, 25 Jan 2026 17:14:28 +0100
Subject: [PATCH 073/142] chore: Update outdated GitHub Actions versions
 (#17487)

---
 .github/workflows/ci.yml                 | 20 ++++++++++----------
 .github/workflows/pkg.pr.new-comment.yml |  4 ++--
 .github/workflows/pkg.pr.new.yml         |  8 ++++----
 .github/workflows/release.yml            |  4 ++--
 4 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 51408fc8cc..8dcf1e45dc 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -32,9 +32,9 @@ jobs:
             os: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: pnpm/action-setup@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@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@v4
+      - uses: actions/checkout@v6
       - uses: pnpm/action-setup@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: 22
           cache: pnpm
@@ -65,9 +65,9 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: pnpm/action-setup@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: 24
           cache: pnpm
@@ -82,9 +82,9 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: pnpm/action-setup@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: 18
           cache: pnpm
@@ -103,9 +103,9 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 15
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: pnpm/action-setup@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: 18
           cache: pnpm
diff --git a/.github/workflows/pkg.pr.new-comment.yml b/.github/workflows/pkg.pr.new-comment.yml
index 8bf13bb8f1..64495cc5c8 100644
--- a/.github/workflows/pkg.pr.new-comment.yml
+++ b/.github/workflows/pkg.pr.new-comment.yml
@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Download artifact
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v7
         with:
           name: output
           github-token: ${{ secrets.GITHUB_TOKEN }}
@@ -23,7 +23,7 @@ jobs:
 
       - run: ls -R .
       - name: 'Post or update comment'
-        uses: actions/github-script@v6
+        uses: actions/github-script@v8
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           script: |
diff --git a/.github/workflows/pkg.pr.new.yml b/.github/workflows/pkg.pr.new.yml
index 49303f1684..252cbed769 100644
--- a/.github/workflows/pkg.pr.new.yml
+++ b/.github/workflows/pkg.pr.new.yml
@@ -10,9 +10,9 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: pnpm/action-setup@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: 22.x
           cache: pnpm
@@ -25,7 +25,7 @@ jobs:
 
       - run: pnpx pkg-pr-new publish --comment=off --json output.json --compact --no-template './packages/svelte'
       - name: Add metadata to output
-        uses: actions/github-script@v6
+        uses: actions/github-script@v8
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           script: |
@@ -36,7 +36,7 @@ jobs:
             output.ref = context.ref;
             fs.writeFileSync('output.json', JSON.stringify(output), 'utf8');
       - name: Upload output
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         with:
           name: output
           path: ./output.json
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 80d2ad1f8e..aa32e3c5cd 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@v4
+        uses: actions/checkout@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@v4
       - name: Setup Node.js
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: 24.x
           cache: pnpm

From c3fcc15cfa5db621d1ac808a1885748377edd7da Mon Sep 17 00:00:00 2001
From: dive2tech <phivesyard@gmail.com>
Date: Mon, 26 Jan 2026 09:11:01 -0500
Subject: [PATCH 074/142] feat: improve text/binary file detection in hash.js
 (#17543)

* Improve text/binary file detection in hash.js

Replace hardcoded text: true with proper detection logic that:
- Checks for null bytes to identify binary files
- Validates UTF-8 encoding with round-trip verification
- Handles binary files by encoding them as base64

This fixes the TODO comment and makes the script more robust.

* tweak

* snake_case

---------

Co-authored-by: Gittensor Miner <miner@gittensor.io>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 playgrounds/sandbox/scripts/hash.js | 32 +++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/playgrounds/sandbox/scripts/hash.js b/playgrounds/sandbox/scripts/hash.js
index e70dfc471a..fdfe2d1aa7 100644
--- a/playgrounds/sandbox/scripts/hash.js
+++ b/playgrounds/sandbox/scripts/hash.js
@@ -1,16 +1,44 @@
 import fs from 'node:fs';
 
+/**
+ * Detects if a file is text or binary by checking for null bytes
+ * and validating UTF-8 encoding
+ * @param {string} filepath - Path to the file
+ * @returns {boolean} - true if file is text, false if binary
+ */
+function is_text_file(filepath) {
+	const buffer = fs.readFileSync(filepath);
+	// Check for null bytes which indicate binary files
+	for (let i = 0; i < buffer.length; i++) {
+		if (buffer[i] === 0) {
+			return false;
+		}
+	}
+	// Validate UTF-8 encoding
+	try {
+		const text = buffer.toString('utf-8');
+		// Verify round-trip encoding to ensure valid UTF-8
+		const encoded = Buffer.from(text, 'utf-8');
+		return buffer.equals(encoded);
+	} catch {
+		return false;
+	}
+}
+
 const files = [];
 
 for (const basename of fs.readdirSync('src')) {
 	if (fs.statSync(`src/${basename}`).isDirectory()) continue;
 
+	const filepath = `src/${basename}`;
+	const text = is_text_file(filepath);
+
 	files.push({
 		type: 'file',
 		name: basename,
 		basename,
-		contents: fs.readFileSync(`src/${basename}`, 'utf-8'),
-		text: true // TODO might not be
+		contents: fs.readFileSync(filepath, text ? 'utf-8' : 'base64'),
+		text
 	});
 }
 

From efcb7353bb4526a64d8d69e2d43ce8314d8ceb8c Mon Sep 17 00:00:00 2001
From: ai-man-codes <aimansingh00@gmail.com>
Date: Mon, 26 Jan 2026 20:59:12 +0530
Subject: [PATCH 075/142] fix: handle falsy dynamic components in SSR (#17542)

* fix: handle falsy dynamic components in SSR

Closes #17408

Adds a dynamic check for the component in the SSR.

Changes:
- Modified server-side component renderer to use b.maybe_call for dynamic components
- Added SSR test case for falsy component values

* fix types

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/purple-guests-punch.md                    |  5 +++++
 .../3-transform/server/visitors/shared/component.js  | 12 ++++--------
 .../samples/falsy-dynamic-component/_expected.html   |  1 +
 .../samples/falsy-dynamic-component/main.svelte      |  6 ++++++
 4 files changed, 16 insertions(+), 8 deletions(-)
 create mode 100644 .changeset/purple-guests-punch.md
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/falsy-dynamic-component/_expected.html
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/falsy-dynamic-component/main.svelte

diff --git a/.changeset/purple-guests-punch.md b/.changeset/purple-guests-punch.md
new file mode 100644
index 0000000000..f18a1962d6
--- /dev/null
+++ b/.changeset/purple-guests-punch.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: handle false dynamic components in SSR
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/component.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/component.js
index a90b5e41df..cfd9a27d7b 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/component.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/component.js
@@ -295,22 +295,18 @@ export function build_inline_component(node, expression, context) {
 					b.array(props_and_spreads.map((p) => (Array.isArray(p) ? b.object(p) : p)))
 				);
 
+	const dynamic =
+		node.type === 'SvelteComponent' || (node.type === 'Component' && node.metadata.dynamic);
+
 	/** @type {Statement} */
 	let statement = b.stmt(
-		(node.type === 'SvelteComponent' ? b.maybe_call : b.call)(
-			expression,
-			b.id('$$renderer'),
-			props_expression
-		)
+		(dynamic ? b.maybe_call : b.call)(expression, b.id('$$renderer'), props_expression)
 	);
 
 	if (snippet_declarations.length > 0) {
 		statement = b.block([...snippet_declarations, statement]);
 	}
 
-	const dynamic =
-		node.type === 'SvelteComponent' || (node.type === 'Component' && node.metadata.dynamic);
-
 	if (custom_css_props.length > 0) {
 		statement = b.stmt(
 			b.call(
diff --git a/packages/svelte/tests/server-side-rendering/samples/falsy-dynamic-component/_expected.html b/packages/svelte/tests/server-side-rendering/samples/falsy-dynamic-component/_expected.html
new file mode 100644
index 0000000000..d87d3602f8
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/falsy-dynamic-component/_expected.html
@@ -0,0 +1 @@
+<h1>Test</h1>
\ No newline at end of file
diff --git a/packages/svelte/tests/server-side-rendering/samples/falsy-dynamic-component/main.svelte b/packages/svelte/tests/server-side-rendering/samples/falsy-dynamic-component/main.svelte
new file mode 100644
index 0000000000..ee6dabc9aa
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/falsy-dynamic-component/main.svelte
@@ -0,0 +1,6 @@
+<script>
+	let Component = $state();
+</script>
+
+<h1>Test</h1>
+<Component />
\ No newline at end of file

From 5e0d18d2102c05c14ba71a52a222f4f126215f31 Mon Sep 17 00:00:00 2001
From: David <david@hmnd.io>
Date: Mon, 26 Jan 2026 14:26:16 -0800
Subject: [PATCH 076/142] fix: advance hydration before skipping settled async
 blocks (#17539)

* fix: advance hydration before skipping settled async blocks

* add test sample

* simplify
---
 .changeset/common-parrots-do.md                    |  5 +++++
 .../svelte/src/internal/client/dom/blocks/async.js | 10 ++++++----
 .../async-settled-blockers-hydration/_config.js    | 14 ++++++++++++++
 .../async-settled-blockers-hydration/main.svelte   | 13 +++++++++++++
 4 files changed, 38 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/common-parrots-do.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-settled-blockers-hydration/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-settled-blockers-hydration/main.svelte

diff --git a/.changeset/common-parrots-do.md b/.changeset/common-parrots-do.md
new file mode 100644
index 0000000000..d40260f8d1
--- /dev/null
+++ b/.changeset/common-parrots-do.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: hydration failing with settled async blocks
diff --git a/packages/svelte/src/internal/client/dom/blocks/async.js b/packages/svelte/src/internal/client/dom/blocks/async.js
index c2ae07fd17..0e3ab33dda 100644
--- a/packages/svelte/src/internal/client/dom/blocks/async.js
+++ b/packages/svelte/src/internal/client/dom/blocks/async.js
@@ -19,6 +19,12 @@ import { get_boundary } from './boundary.js';
  * @param {(anchor: TemplateNode, ...deriveds: Value[]) => void} fn
  */
 export function async(node, blockers = [], expressions = [], fn) {
+	var was_hydrating = hydrating;
+
+	if (was_hydrating) {
+		hydrate_next();
+	}
+
 	if (expressions.length === 0 && blockers.every((b) => b.settled)) {
 		fn(node);
 		return;
@@ -31,11 +37,7 @@ export function async(node, blockers = [], expressions = [], fn) {
 	boundary.update_pending_count(1);
 	batch.increment(blocking);
 
-	var was_hydrating = hydrating;
-
 	if (was_hydrating) {
-		hydrate_next();
-
 		var previous_hydrate_node = hydrate_node;
 		var end = skip_nodes(false);
 		set_hydrate_node(end);
diff --git a/packages/svelte/tests/runtime-runes/samples/async-settled-blockers-hydration/_config.js b/packages/svelte/tests/runtime-runes/samples/async-settled-blockers-hydration/_config.js
new file mode 100644
index 0000000000..f6f6c81350
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-settled-blockers-hydration/_config.js
@@ -0,0 +1,14 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	skip_mode: ['server'],
+	skip_no_async: true,
+
+	ssrHtml: `<div>1</div><p>after</p>`,
+
+	async test({ assert, target }) {
+		await tick();
+		assert.htmlEqual(target.innerHTML, '<div>1</div><p>after</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-settled-blockers-hydration/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-settled-blockers-hydration/main.svelte
new file mode 100644
index 0000000000..1b1dc17242
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-settled-blockers-hydration/main.svelte
@@ -0,0 +1,13 @@
+<script>
+	const n = $derived(await Promise.resolve(1));
+</script>
+
+{#snippet child(n)}
+	<div>{n}</div>
+{/snippet}
+
+{#if n}
+	{@render child(n)}
+{/if}
+
+<p>after</p>

From 5872b89fb8e6e01dac9c9c9d4fdc3e9ae416014c Mon Sep 17 00:00:00 2001
From: Richman018 <239411042+Richman018@users.noreply.github.com>
Date: Tue, 27 Jan 2026 07:00:12 +0800
Subject: [PATCH 077/142] fix: add pointer and touch events to
 a11y_no_static_element_interactions warning (#17548)

* fix: add pointer and touch events to a11y_no_static_element_interactions warning

Fixes #17527

The a11y_no_static_element_interactions warning now triggers for pointer
and touch events (onpointerdown, onpointerenter, ontouchstart, etc.)
in addition to mouse and drag events.

This ensures accessibility warnings are consistent across all pointer
input methods.

* fix test

---------

Co-authored-by: Daniel <daniel@example.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .../visitors/shared/a11y/constants.js         | 16 ++++++++-
 .../input.svelte                              |  3 ++
 .../warnings.json                             | 36 +++++++++++++++++++
 3 files changed, 54 insertions(+), 1 deletion(-)

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 a1b70f2207..684ea92094 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
@@ -67,7 +67,21 @@ export const a11y_interactive_handlers = [
 	'mousemove',
 	'mouseout',
 	'mouseover',
-	'mouseup'
+	'mouseup',
+	// Pointer events
+	'pointerdown',
+	'pointerup',
+	'pointermove',
+	'pointerenter',
+	'pointerleave',
+	'pointerover',
+	'pointerout',
+	'pointercancel',
+	// Touch events
+	'touchstart',
+	'touchend',
+	'touchmove',
+	'touchcancel'
 ];
 
 export const a11y_recommended_interactive_handlers = [
diff --git a/packages/svelte/tests/validator/samples/a11y-no-static-element-interactions/input.svelte b/packages/svelte/tests/validator/samples/a11y-no-static-element-interactions/input.svelte
index ee7ed4f084..8829d784c8 100644
--- a/packages/svelte/tests/validator/samples/a11y-no-static-element-interactions/input.svelte
+++ b/packages/svelte/tests/validator/samples/a11y-no-static-element-interactions/input.svelte
@@ -17,3 +17,6 @@
 <div on:keydown={() => {}}></div>
 <!-- svelte-ignore a11y_missing_attribute -->
 <a on:mousedown={() => {}} on:mouseup={() => {}} on:copy={() => {}}>link</a>
+<div on:pointerdown={() => {}}></div>
+<div on:pointerenter={() => {}}></div>
+<div on:touchstart={() => {}}></div>
diff --git a/packages/svelte/tests/validator/samples/a11y-no-static-element-interactions/warnings.json b/packages/svelte/tests/validator/samples/a11y-no-static-element-interactions/warnings.json
index ab4b58a839..41325a8756 100644
--- a/packages/svelte/tests/validator/samples/a11y-no-static-element-interactions/warnings.json
+++ b/packages/svelte/tests/validator/samples/a11y-no-static-element-interactions/warnings.json
@@ -22,5 +22,41 @@
 			"column": 0,
 			"line": 19
 		}
+	},
+	{
+		"code": "a11y_no_static_element_interactions",
+		"end": {
+			"column": 37,
+			"line": 20
+		},
+		"message": "`<div>` with a pointerdown handler must have an ARIA role",
+		"start": {
+			"column": 0,
+			"line": 20
+		}
+	},
+	{
+		"code": "a11y_no_static_element_interactions",
+		"end": {
+			"column": 38,
+			"line": 21
+		},
+		"message": "`<div>` with a pointerenter handler must have an ARIA role",
+		"start": {
+			"column": 0,
+			"line": 21
+		}
+	},
+	{
+		"code": "a11y_no_static_element_interactions",
+		"end": {
+			"column": 36,
+			"line": 22
+		},
+		"message": "`<div>` with a touchstart handler must have an ARIA role",
+		"start": {
+			"column": 0,
+			"line": 22
+		}
 	}
 ]

From 97684d32a01b8592931987036986ba44ccd85bad Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Mon, 26 Jan 2026 18:07:14 -0500
Subject: [PATCH 078/142] add missing changeset for #17548 (#17551)

---
 .changeset/public-streets-turn.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/public-streets-turn.md

diff --git a/.changeset/public-streets-turn.md b/.changeset/public-streets-turn.md
new file mode 100644
index 0000000000..ed9ad14241
--- /dev/null
+++ b/.changeset/public-streets-turn.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: add pointer and touch events to a11y_no_static_element_interactions warning

From 9662010a135937b7a920eaf93933be7b8b0c9c9e Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Mon, 26 Jan 2026 18:35:21 -0500
Subject: [PATCH 079/142] Version Packages (#17537)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/common-parrots-do.md   |  5 -----
 .changeset/public-streets-turn.md |  5 -----
 .changeset/purple-guests-punch.md |  5 -----
 .changeset/wise-emus-hunt.md      |  5 -----
 .changeset/yellow-bobcats-hope.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/common-parrots-do.md
 delete mode 100644 .changeset/public-streets-turn.md
 delete mode 100644 .changeset/purple-guests-punch.md
 delete mode 100644 .changeset/wise-emus-hunt.md
 delete mode 100644 .changeset/yellow-bobcats-hope.md

diff --git a/.changeset/common-parrots-do.md b/.changeset/common-parrots-do.md
deleted file mode 100644
index d40260f8d1..0000000000
--- a/.changeset/common-parrots-do.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: hydration failing with settled async blocks
diff --git a/.changeset/public-streets-turn.md b/.changeset/public-streets-turn.md
deleted file mode 100644
index ed9ad14241..0000000000
--- a/.changeset/public-streets-turn.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: add pointer and touch events to a11y_no_static_element_interactions warning
diff --git a/.changeset/purple-guests-punch.md b/.changeset/purple-guests-punch.md
deleted file mode 100644
index f18a1962d6..0000000000
--- a/.changeset/purple-guests-punch.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: handle false dynamic components in SSR
diff --git a/.changeset/wise-emus-hunt.md b/.changeset/wise-emus-hunt.md
deleted file mode 100644
index c8b3f93de8..0000000000
--- a/.changeset/wise-emus-hunt.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: avoid unnecessary block effect re-runs after async work completes
diff --git a/.changeset/yellow-bobcats-hope.md b/.changeset/yellow-bobcats-hope.md
deleted file mode 100644
index dffeea3177..0000000000
--- a/.changeset/yellow-bobcats-hope.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: avoid using dev-mode array.includes wrapper on internal array checks
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index e619f55654..762d8721ff 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,19 @@
 # svelte
 
+## 5.48.3
+
+### Patch Changes
+
+- fix: hydration failing with settled async blocks ([#17539](https://github.com/sveltejs/svelte/pull/17539))
+
+- fix: add pointer and touch events to a11y_no_static_element_interactions warning ([#17551](https://github.com/sveltejs/svelte/pull/17551))
+
+- fix: handle false dynamic components in SSR ([#17542](https://github.com/sveltejs/svelte/pull/17542))
+
+- fix: avoid unnecessary block effect re-runs after async work completes ([#17535](https://github.com/sveltejs/svelte/pull/17535))
+
+- fix: avoid using dev-mode array.includes wrapper on internal array checks ([#17536](https://github.com/sveltejs/svelte/pull/17536))
+
 ## 5.48.2
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 7763aba87e..5aa7c92c4e 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": "5.48.2",
+  "version": "5.48.3",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 2b30052317..c9c4c3fc9c 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 = '5.48.2';
+export const VERSION = '5.48.3';
 export const PUBLIC_VERSION = '5';

From 83eb9dac64109eb43c906dd5ea73d7b2bdc076a3 Mon Sep 17 00:00:00 2001
From: Tee Ming <chewteeming01@gmail.com>
Date: Tue, 27 Jan 2026 23:50:32 +0800
Subject: [PATCH 080/142] fix: avoid duplicating escaped characters when
 parsing styles (#17554)

* fix and test

* changeset

* format

* increment index and escape early instead
---
 .changeset/true-berries-behave.md                 |  5 +++++
 .../src/compiler/phases/1-parse/read/style.js     |  4 ++++
 packages/svelte/tests/css-parse.test.ts           | 15 +++++++++++++++
 3 files changed, 24 insertions(+)
 create mode 100644 .changeset/true-berries-behave.md

diff --git a/.changeset/true-berries-behave.md b/.changeset/true-berries-behave.md
new file mode 100644
index 0000000000..0b9df87c4f
--- /dev/null
+++ b/.changeset/true-berries-behave.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: avoid duplicating escaped characters in CSS AST
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 c88a3707c1..55647b2c94 100644
--- a/packages/svelte/src/compiler/phases/1-parse/read/style.js
+++ b/packages/svelte/src/compiler/phases/1-parse/read/style.js
@@ -508,8 +508,12 @@ function read_value(parser) {
 		if (escaped) {
 			value += '\\' + char;
 			escaped = false;
+			parser.index++;
+			continue;
 		} else if (char === '\\') {
 			escaped = true;
+			parser.index++;
+			continue;
 		} else if (char === quote_mark) {
 			quote_mark = null;
 		} else if (char === ')') {
diff --git a/packages/svelte/tests/css-parse.test.ts b/packages/svelte/tests/css-parse.test.ts
index fcb9bdc010..4d8ef8601b 100644
--- a/packages/svelte/tests/css-parse.test.ts
+++ b/packages/svelte/tests/css-parse.test.ts
@@ -135,4 +135,19 @@ describe('parseCss', () => {
 			}
 		}
 	});
+
+	it('parses escaped characters', () => {
+		const ast = parseCss("div { background: url('./example.png?\\''); }");
+		assert.equal(ast.type, 'StyleSheet');
+		assert.equal(ast.children.length, 1);
+		const rule = ast.children[0];
+		assert.equal(rule.type, 'Rule');
+		if (rule.type === 'Rule') {
+			const declaration = rule.block.children[0];
+			assert.equal(declaration.type, 'Declaration');
+			if (declaration.type === 'Declaration') {
+				assert.equal(declaration.value, "url('./example.png?\\'')");
+			}
+		}
+	});
 });

From e9d580ed405ed20315b272ef89efc83d8854be95 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Tue, 27 Jan 2026 13:18:43 -0500
Subject: [PATCH 081/142] Version Packages (#17555)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/true-berries-behave.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/true-berries-behave.md

diff --git a/.changeset/true-berries-behave.md b/.changeset/true-berries-behave.md
deleted file mode 100644
index 0b9df87c4f..0000000000
--- a/.changeset/true-berries-behave.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: avoid duplicating escaped characters in CSS AST
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 762d8721ff..486e688b5c 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,11 @@
 # svelte
 
+## 5.48.4
+
+### Patch Changes
+
+- fix: avoid duplicating escaped characters in CSS AST ([#17554](https://github.com/sveltejs/svelte/pull/17554))
+
 ## 5.48.3
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 5aa7c92c4e..7ca1b569f6 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": "5.48.3",
+  "version": "5.48.4",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index c9c4c3fc9c..fe300a4a43 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 = '5.48.3';
+export const VERSION = '5.48.4';
 export const PUBLIC_VERSION = '5';

From 02b5d94b3a692bb12db2054c00a549cd982b0e5a Mon Sep 17 00:00:00 2001
From: David <david@hmnd.io>
Date: Tue, 27 Jan 2026 14:47:47 -0800
Subject: [PATCH 082/142] fix: each block breaking with effects interspersed
 among items (#17550)

* fix: each block breaking with effects interspersed among items

* test sample with interspersed non-branch effects

* Apply suggestion from @Rich-Harris

* use $effect.pre in sample instead

---------

Co-authored-by: Rich Harris <hello@rich-harris.dev>
---
 .changeset/thirty-carpets-attack.md           |  5 +++
 .../src/internal/client/dom/blocks/each.js    | 24 ++++++++---
 .../each-non-branch-effects/_config.js        | 43 +++++++++++++++++++
 .../each-non-branch-effects/main.svelte       | 30 +++++++++++++
 4 files changed, 96 insertions(+), 6 deletions(-)
 create mode 100644 .changeset/thirty-carpets-attack.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/each-non-branch-effects/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/each-non-branch-effects/main.svelte

diff --git a/.changeset/thirty-carpets-attack.md b/.changeset/thirty-carpets-attack.md
new file mode 100644
index 0000000000..6b3949989a
--- /dev/null
+++ b/.changeset/thirty-carpets-attack.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: each block breaking with effects interspersed among items
diff --git a/packages/svelte/src/internal/client/dom/blocks/each.js b/packages/svelte/src/internal/client/dom/blocks/each.js
index f7c9faf2b1..232656ec11 100644
--- a/packages/svelte/src/internal/client/dom/blocks/each.js
+++ b/packages/svelte/src/internal/client/dom/blocks/each.js
@@ -34,7 +34,7 @@ import {
 } from '../../reactivity/effects.js';
 import { source, mutable_source, internal_set } from '../../reactivity/sources.js';
 import { array_from, is_array } from '../../../shared/utils.js';
-import { COMMENT_NODE, EFFECT_OFFSCREEN, INERT } from '#client/constants';
+import { BRANCH_EFFECT, COMMENT_NODE, EFFECT_OFFSCREEN, INERT } from '#client/constants';
 import { queue_micro_task } from '../task.js';
 import { get } from '../../runtime.js';
 import { DEV } from 'esm-env';
@@ -336,6 +336,18 @@ export function each(node, flags, get_collection, get_key, render_fn, fallback_f
 	}
 }
 
+/**
+ * Skip past any non-branch effects (which could be created with `createSubscriber`, for example) to find the next branch effect
+ * @param {Effect | null} effect
+ * @returns {Effect | null}
+ */
+function skip_to_branch(effect) {
+	while (effect !== null && (effect.f & BRANCH_EFFECT) === 0) {
+		effect = effect.next;
+	}
+	return effect;
+}
+
 /**
  * Add, remove, or reorder items output by an each block as its input changes
  * @template V
@@ -351,7 +363,7 @@ function reconcile(state, array, anchor, flags, get_key) {
 
 	var length = array.length;
 	var items = state.items;
-	var current = state.effect.first;
+	var current = skip_to_branch(state.effect.first);
 
 	/** @type {undefined | Set<Effect>} */
 	var seen;
@@ -431,7 +443,7 @@ function reconcile(state, array, anchor, flags, get_key) {
 				matched = [];
 				stashed = [];
 
-				current = prev.next;
+				current = skip_to_branch(prev.next);
 				continue;
 			}
 		}
@@ -495,7 +507,7 @@ function reconcile(state, array, anchor, flags, get_key) {
 			while (current !== null && current !== effect) {
 				(seen ??= new Set()).add(current);
 				stashed.push(current);
-				current = current.next;
+				current = skip_to_branch(current.next);
 			}
 
 			if (current === null) {
@@ -508,7 +520,7 @@ function reconcile(state, array, anchor, flags, get_key) {
 		}
 
 		prev = effect;
-		current = effect.next;
+		current = skip_to_branch(effect.next);
 	}
 
 	if (state.outrogroups !== null) {
@@ -542,7 +554,7 @@ function reconcile(state, array, anchor, flags, get_key) {
 				to_destroy.push(current);
 			}
 
-			current = current.next;
+			current = skip_to_branch(current.next);
 		}
 
 		var destroy_length = to_destroy.length;
diff --git a/packages/svelte/tests/runtime-runes/samples/each-non-branch-effects/_config.js b/packages/svelte/tests/runtime-runes/samples/each-non-branch-effects/_config.js
new file mode 100644
index 0000000000..acf84f6809
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/each-non-branch-effects/_config.js
@@ -0,0 +1,43 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		const addBtn = /** @type {HTMLElement} */ (target.querySelector('button.add'));
+		const removeBtn = /** @type {HTMLElement} */ (target.querySelector('button.remove'));
+
+		const btnHtml = '<button class="add">add</button><button class="remove">remove</button>';
+
+		assert.htmlEqual(target.innerHTML, btnHtml);
+
+		addBtn.click();
+		flushSync();
+
+		assert.htmlEqual(target.innerHTML, `<span>1</span>${btnHtml}`);
+
+		addBtn.click();
+		flushSync();
+
+		assert.htmlEqual(target.innerHTML, `<span>1</span><span>2</span>${btnHtml}`);
+
+		addBtn.click();
+		flushSync();
+
+		assert.htmlEqual(target.innerHTML, `<span>1</span><span>2</span><span>3</span>${btnHtml}`);
+
+		removeBtn.click();
+		flushSync();
+
+		assert.htmlEqual(target.innerHTML, `<span>1</span><span>2</span>${btnHtml}`);
+
+		removeBtn.click();
+		flushSync();
+
+		assert.htmlEqual(target.innerHTML, `<span>1</span>${btnHtml}`);
+
+		addBtn.click();
+		flushSync();
+
+		assert.htmlEqual(target.innerHTML, `<span>1</span><span>2</span>${btnHtml}`);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/each-non-branch-effects/main.svelte b/packages/svelte/tests/runtime-runes/samples/each-non-branch-effects/main.svelte
new file mode 100644
index 0000000000..7869d095dd
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/each-non-branch-effects/main.svelte
@@ -0,0 +1,30 @@
+<script>
+	let items = $state([]);
+
+	const proxy = new Proxy(items, {
+		get: (target, prop) => {
+			try {
+				$effect.pre(() => {
+					return () => {};
+				});
+			} catch {}
+
+			return Reflect.get(target, prop);
+		}
+	});
+
+	function add() {
+		items.push(items.length + 1);
+	}
+
+	function remove() {
+		items.pop();
+	}
+</script>
+
+{#each proxy as item}
+	<span>{item}</span>
+{/each}
+
+<button class="add" onclick={add}>add</button>
+<button class="remove" onclick={remove}>remove</button>

From 8c8a22add47693e9e2c9b1e7bfedd4dd4cf56469 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Tue, 27 Jan 2026 19:06:24 -0500
Subject: [PATCH 083/142] fix: prevent unintended exports from namespaces
 (#17562)

---
 .changeset/stale-words-count.md  |  5 +++++
 packages/svelte/src/ambient.d.ts | 21 +++++++++++++++++++++
 packages/svelte/types/index.d.ts | 21 +++++++++++++++++++++
 3 files changed, 47 insertions(+)
 create mode 100644 .changeset/stale-words-count.md

diff --git a/.changeset/stale-words-count.md b/.changeset/stale-words-count.md
new file mode 100644
index 0000000000..d8d8c3102e
--- /dev/null
+++ b/.changeset/stale-words-count.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: prevent unintended exports from namespaces
diff --git a/packages/svelte/src/ambient.d.ts b/packages/svelte/src/ambient.d.ts
index 823dbde9a4..ec5b799470 100644
--- a/packages/svelte/src/ambient.d.ts
+++ b/packages/svelte/src/ambient.d.ts
@@ -173,6 +173,9 @@ declare namespace $state {
 	export const prototype: never;
 	/** @deprecated */
 	export const toString: never;
+
+	// needed to keep private stuff private
+	export {};
 }
 
 /**
@@ -230,6 +233,9 @@ declare namespace $derived {
 	export const prototype: never;
 	/** @deprecated */
 	export const toString: never;
+
+	// needed to keep private stuff private
+	export {};
 }
 
 /**
@@ -346,6 +352,9 @@ declare namespace $effect {
 	export const prototype: never;
 	/** @deprecated */
 	export const toString: never;
+
+	// needed to keep private stuff private
+	export {};
 }
 
 /**
@@ -389,6 +398,9 @@ declare namespace $props {
 	export const prototype: never;
 	/** @deprecated */
 	export const toString: never;
+
+	// needed to keep private stuff private
+	export {};
 }
 
 /**
@@ -423,6 +435,9 @@ declare namespace $bindable {
 	export const prototype: never;
 	/** @deprecated */
 	export const toString: never;
+
+	// needed to keep private stuff private
+	export {};
 }
 
 /**
@@ -485,6 +500,9 @@ declare namespace $inspect {
 	export const prototype: never;
 	/** @deprecated */
 	export const toString: never;
+
+	// needed to keep private stuff private
+	export {};
 }
 
 /**
@@ -529,4 +547,7 @@ declare namespace $host {
 	export const prototype: never;
 	/** @deprecated */
 	export const toString: never;
+
+	// needed to keep private stuff private
+	export {};
 }
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index 9e569126bb..128de134ed 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -3345,6 +3345,9 @@ declare namespace $state {
 	export const prototype: never;
 	/** @deprecated */
 	export const toString: never;
+
+	// needed to keep private stuff private
+	export {};
 }
 
 /**
@@ -3402,6 +3405,9 @@ declare namespace $derived {
 	export const prototype: never;
 	/** @deprecated */
 	export const toString: never;
+
+	// needed to keep private stuff private
+	export {};
 }
 
 /**
@@ -3518,6 +3524,9 @@ declare namespace $effect {
 	export const prototype: never;
 	/** @deprecated */
 	export const toString: never;
+
+	// needed to keep private stuff private
+	export {};
 }
 
 /**
@@ -3561,6 +3570,9 @@ declare namespace $props {
 	export const prototype: never;
 	/** @deprecated */
 	export const toString: never;
+
+	// needed to keep private stuff private
+	export {};
 }
 
 /**
@@ -3595,6 +3607,9 @@ declare namespace $bindable {
 	export const prototype: never;
 	/** @deprecated */
 	export const toString: never;
+
+	// needed to keep private stuff private
+	export {};
 }
 
 /**
@@ -3657,6 +3672,9 @@ declare namespace $inspect {
 	export const prototype: never;
 	/** @deprecated */
 	export const toString: never;
+
+	// needed to keep private stuff private
+	export {};
 }
 
 /**
@@ -3701,6 +3719,9 @@ declare namespace $host {
 	export const prototype: never;
 	/** @deprecated */
 	export const toString: never;
+
+	// needed to keep private stuff private
+	export {};
 }
 
 //# sourceMappingURL=index.d.ts.map

From 30cea1f9a0cbf41f466083f9761a8f4d544d700a Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Tue, 27 Jan 2026 19:16:59 -0500
Subject: [PATCH 084/142] fix: run boundary `onerror` callbacks in a microtask,
 in case they result in the boundary's destruction (#17561)

* fix: mark parent effect as dirty on error boundary initialization

This change ensures that if an error occurs while a parent effect is still initializing, the parent effect is marked as dirty and scheduled to re-run. This addresses scenarios where state updates in the onerror handler do not trigger a re-evaluation of the condition, improving error handling in Svelte components.

* chore: add changeset for #17553

* fix: run boundary  callbacks in a microtask, in case they result in the boundary's destruction

---------

Co-authored-by: frozenflux2 <snowflake30518@gmail.com>
---
 .changeset/fix-if-block-boundary-onerror.md   |  5 ++++
 .../internal/client/dom/blocks/boundary.js    | 28 ++++++++-----------
 .../samples/error-boundary-24/Child.svelte    |  5 ++++
 .../samples/error-boundary-24/_config.js      | 13 +++++++++
 .../samples/error-boundary-24/main.svelte     | 19 +++++++++++++
 .../samples/error-boundary-25/Child.svelte    |  8 ++++++
 .../samples/error-boundary-25/_config.js      | 13 +++++++++
 .../samples/error-boundary-25/main.svelte     | 19 +++++++++++++
 8 files changed, 94 insertions(+), 16 deletions(-)
 create mode 100644 .changeset/fix-if-block-boundary-onerror.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/error-boundary-24/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/error-boundary-24/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/error-boundary-24/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/error-boundary-25/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/error-boundary-25/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/error-boundary-25/main.svelte

diff --git a/.changeset/fix-if-block-boundary-onerror.md b/.changeset/fix-if-block-boundary-onerror.md
new file mode 100644
index 0000000000..608dce6814
--- /dev/null
+++ b/.changeset/fix-if-block-boundary-onerror.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: run boundary `onerror` callbacks in a microtask, in case they result in the boundary's destruction
diff --git a/packages/svelte/src/internal/client/dom/blocks/boundary.js b/packages/svelte/src/internal/client/dom/blocks/boundary.js
index 90a695551a..ef5f0e116d 100644
--- a/packages/svelte/src/internal/client/dom/blocks/boundary.js
+++ b/packages/svelte/src/internal/client/dom/blocks/boundary.js
@@ -1,5 +1,6 @@
 /** @import { Effect, Source, TemplateNode, } from '#client' */
 import {
+	BLOCK_EFFECT,
 	BOUNDARY_EFFECT,
 	COMMENT_NODE,
 	DIRTY,
@@ -449,21 +450,16 @@ export class Boundary {
 			}
 		};
 
-		var previous_reaction = active_reaction;
-
-		try {
-			set_active_reaction(null);
-			calling_on_error = true;
-			onerror?.(error, reset);
-			calling_on_error = false;
-		} catch (error) {
-			invoke_error_boundary(error, this.#effect && this.#effect.parent);
-		} finally {
-			set_active_reaction(previous_reaction);
-		}
+		queue_micro_task(() => {
+			try {
+				calling_on_error = true;
+				onerror?.(error, reset);
+				calling_on_error = false;
+			} catch (error) {
+				invoke_error_boundary(error, this.#effect && this.#effect.parent);
+			}
 
-		if (failed) {
-			queue_micro_task(() => {
+			if (failed) {
 				this.#failed_effect = this.#run(() => {
 					Batch.ensure();
 					this.#is_creating_fallback = true;
@@ -483,8 +479,8 @@ export class Boundary {
 						this.#is_creating_fallback = false;
 					}
 				});
-			});
-		}
+			}
+		});
 	}
 }
 
diff --git a/packages/svelte/tests/runtime-runes/samples/error-boundary-24/Child.svelte b/packages/svelte/tests/runtime-runes/samples/error-boundary-24/Child.svelte
new file mode 100644
index 0000000000..cd25ece1b5
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/error-boundary-24/Child.svelte
@@ -0,0 +1,5 @@
+<script>
+	throw new Error('child error');
+</script>
+
+<p>Child content</p>
diff --git a/packages/svelte/tests/runtime-runes/samples/error-boundary-24/_config.js b/packages/svelte/tests/runtime-runes/samples/error-boundary-24/_config.js
new file mode 100644
index 0000000000..b5b5f296d8
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/error-boundary-24/_config.js
@@ -0,0 +1,13 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['client'],
+	test({ assert, target }) {
+		flushSync();
+
+		// When exception is set by onerror, the {#if !exception} block should hide
+		// and only the {#if exception} block should be visible
+		assert.htmlEqual(target.innerHTML, '<p>caught error: child error</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/error-boundary-24/main.svelte b/packages/svelte/tests/runtime-runes/samples/error-boundary-24/main.svelte
new file mode 100644
index 0000000000..5116580003
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/error-boundary-24/main.svelte
@@ -0,0 +1,19 @@
+<script>
+	import Child from './Child.svelte';
+
+	let exception = $state();
+	const onerror = (e) => {
+		exception = e;
+	};
+</script>
+
+{#if !exception}
+	<p>condition is {String(!exception)}</p>
+	<svelte:boundary {onerror}>
+		<Child />
+	</svelte:boundary>
+{/if}
+
+{#if exception}
+	<p>caught error: {exception.message}</p>
+{/if}
diff --git a/packages/svelte/tests/runtime-runes/samples/error-boundary-25/Child.svelte b/packages/svelte/tests/runtime-runes/samples/error-boundary-25/Child.svelte
new file mode 100644
index 0000000000..3d5770fc61
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/error-boundary-25/Child.svelte
@@ -0,0 +1,8 @@
+<script>
+	// it's important for the test that this isn't an `Error`
+	throw 'child error'
+</script>
+
+<p>
+	boom
+</p>
diff --git a/packages/svelte/tests/runtime-runes/samples/error-boundary-25/_config.js b/packages/svelte/tests/runtime-runes/samples/error-boundary-25/_config.js
new file mode 100644
index 0000000000..b5b5f296d8
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/error-boundary-25/_config.js
@@ -0,0 +1,13 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['client'],
+	test({ assert, target }) {
+		flushSync();
+
+		// When exception is set by onerror, the {#if !exception} block should hide
+		// and only the {#if exception} block should be visible
+		assert.htmlEqual(target.innerHTML, '<p>caught error: child error</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/error-boundary-25/main.svelte b/packages/svelte/tests/runtime-runes/samples/error-boundary-25/main.svelte
new file mode 100644
index 0000000000..243d10cf3a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/error-boundary-25/main.svelte
@@ -0,0 +1,19 @@
+<script>
+	import Child from './Child.svelte';
+
+	let exception = $state();
+	const onerror = (e) => {
+		exception = e;
+	};
+</script>
+
+{#if !exception}
+	<p>condition is {String(!exception)}</p>
+	<svelte:boundary {onerror}>
+		<Child />
+	</svelte:boundary>
+{/if}
+
+{#if exception}
+	<p>caught error: {exception}</p>
+{/if}

From 3d285f0ee4771ff3e0476cdb1de8b1ab6a41c473 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Tue, 27 Jan 2026 19:25:42 -0500
Subject: [PATCH 085/142] Version Packages (#17560)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/fix-if-block-boundary-onerror.md |  5 -----
 .changeset/stale-words-count.md             |  5 -----
 .changeset/thirty-carpets-attack.md         |  5 -----
 packages/svelte/CHANGELOG.md                | 10 ++++++++++
 packages/svelte/package.json                |  2 +-
 packages/svelte/src/version.js              |  2 +-
 6 files changed, 12 insertions(+), 17 deletions(-)
 delete mode 100644 .changeset/fix-if-block-boundary-onerror.md
 delete mode 100644 .changeset/stale-words-count.md
 delete mode 100644 .changeset/thirty-carpets-attack.md

diff --git a/.changeset/fix-if-block-boundary-onerror.md b/.changeset/fix-if-block-boundary-onerror.md
deleted file mode 100644
index 608dce6814..0000000000
--- a/.changeset/fix-if-block-boundary-onerror.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: run boundary `onerror` callbacks in a microtask, in case they result in the boundary's destruction
diff --git a/.changeset/stale-words-count.md b/.changeset/stale-words-count.md
deleted file mode 100644
index d8d8c3102e..0000000000
--- a/.changeset/stale-words-count.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: prevent unintended exports from namespaces
diff --git a/.changeset/thirty-carpets-attack.md b/.changeset/thirty-carpets-attack.md
deleted file mode 100644
index 6b3949989a..0000000000
--- a/.changeset/thirty-carpets-attack.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: each block breaking with effects interspersed among items
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 486e688b5c..af503dbb20 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,15 @@
 # svelte
 
+## 5.48.5
+
+### Patch Changes
+
+- fix: run boundary `onerror` callbacks in a microtask, in case they result in the boundary's destruction ([#17561](https://github.com/sveltejs/svelte/pull/17561))
+
+- fix: prevent unintended exports from namespaces ([#17562](https://github.com/sveltejs/svelte/pull/17562))
+
+- fix: each block breaking with effects interspersed among items ([#17550](https://github.com/sveltejs/svelte/pull/17550))
+
 ## 5.48.4
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 7ca1b569f6..ace4c9bd08 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": "5.48.4",
+  "version": "5.48.5",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index fe300a4a43..4338ba83ae 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 = '5.48.4';
+export const VERSION = '5.48.5';
 export const PUBLIC_VERSION = '5';

From 0cbf718aefd458953c84b8a9210c6fd1d2774d28 Mon Sep 17 00:00:00 2001
From: Bladesheng <keadr23@gmail.com>
Date: Wed, 28 Jan 2026 01:37:26 +0100
Subject: [PATCH 086/142] feat: allow passing `ShadowRootInit` to custom
 element `shadow` options (#17088)

* feat: allow passing ShadowRootInit to custom element shadow options

* tests

* add changeset

* update docs

* allow passing functions

* remove newline

* update docs

* fix test

* update docs

* simplify options reading

* remove the option to pass function to `shadow`

* fix whitespace

* fix whitespace

* fix generated types

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/loose-sloths-guess.md              |  5 +++++
 .../docs/07-misc/04-custom-elements.md        | 11 ++++++++--
 .../98-reference/.generated/compile-errors.md |  6 ++++--
 packages/svelte/elements.d.ts                 |  2 +-
 .../messages/compile-errors/template.md       |  6 ++++--
 packages/svelte/src/compiler/errors.js        |  8 +++----
 .../compiler/phases/1-parse/read/options.js   | 10 +++++----
 .../3-transform/client/transform-client.js    | 13 ++++++++++--
 .../svelte/src/compiler/types/template.d.ts   |  2 +-
 .../client/dom/elements/custom-element.js     | 21 ++++++++++++-------
 .../closed-shadow-dom/_config.js              | 13 ++++++++++++
 .../closed-shadow-dom/main.svelte             |  3 +++
 .../shadow-root-init-options/_config.js       | 18 ++++++++++++++++
 .../shadow-root-init-options/main.svelte      | 14 +++++++++++++
 .../samples/tag-non-string/errors.json        |  2 +-
 packages/svelte/types/index.d.ts              |  2 +-
 16 files changed, 108 insertions(+), 28 deletions(-)
 create mode 100644 .changeset/loose-sloths-guess.md
 create mode 100644 packages/svelte/tests/runtime-browser/custom-elements-samples/closed-shadow-dom/_config.js
 create mode 100644 packages/svelte/tests/runtime-browser/custom-elements-samples/closed-shadow-dom/main.svelte
 create mode 100644 packages/svelte/tests/runtime-browser/custom-elements-samples/shadow-root-init-options/_config.js
 create mode 100644 packages/svelte/tests/runtime-browser/custom-elements-samples/shadow-root-init-options/main.svelte

diff --git a/.changeset/loose-sloths-guess.md b/.changeset/loose-sloths-guess.md
new file mode 100644
index 0000000000..450040349d
--- /dev/null
+++ b/.changeset/loose-sloths-guess.md
@@ -0,0 +1,5 @@
+---
+'svelte': minor
+---
+
+feat: allow passing `ShadowRootInit` object to custom element `shadow` option
diff --git a/documentation/docs/07-misc/04-custom-elements.md b/documentation/docs/07-misc/04-custom-elements.md
index 4e5afff7d2..4c2cb3aca3 100644
--- a/documentation/docs/07-misc/04-custom-elements.md
+++ b/documentation/docs/07-misc/04-custom-elements.md
@@ -66,7 +66,10 @@ The inner Svelte component is destroyed in the next tick after the `disconnected
 When constructing a custom element, you can tailor several aspects by defining `customElement` as an object within `<svelte:options>` since Svelte 4. This object may contain the following properties:
 
 - `tag: string`: an optional `tag` property for the custom element's name. If set, a custom element with this tag name will be defined with the document's `customElements` registry upon importing this component.
-- `shadow`: an optional property that can be set to `"none"` to forgo shadow root creation. Note that styles are then no longer encapsulated, and you can't use slots
+- `shadow`: an optional property to modify shadow root properties. It accepts the following values:
+  - `"none"`: No shadow root is created. Note that styles are then no longer encapsulated, and you can't use slots.
+  - `"open"`: Shadow root is created with the `mode: "open"` option.
+  - [`ShadowRootInit`](https://developer.mozilla.org/en-US/docs/Web/API/Element/attachShadow#options): You can pass a settings object that will be passed to `attachShadow()` when shadow root is created.
 - `props`: an optional property to modify certain details and behaviors of your component's properties. It offers the following settings:
   - `attribute: string`: To update a custom element's prop, you have two alternatives: either set the property on the custom element's reference as illustrated above or use an HTML attribute. For the latter, the default attribute name is the lowercase property name. Modify this by assigning `attribute: "<desired name>"`.
   - `reflect: boolean`: By default, updated prop values do not reflect back to the DOM. To enable this behavior, set `reflect: true`.
@@ -78,7 +81,11 @@ When constructing a custom element, you can tailor several aspects by defining `
 <svelte:options
 	customElement={{
 		tag: 'custom-element',
-		shadow: 'none',
+		shadow: {
+			mode: import.meta.env.DEV ? 'open' : 'closed',
+			clonable: true,
+			// ...
+		},
 		props: {
 			name: { reflect: true, type: 'Number', attribute: 'element-index' }
 		},
diff --git a/documentation/docs/98-reference/.generated/compile-errors.md b/documentation/docs/98-reference/.generated/compile-errors.md
index ff452cc674..079b1d2a0a 100644
--- a/documentation/docs/98-reference/.generated/compile-errors.md
+++ b/documentation/docs/98-reference/.generated/compile-errors.md
@@ -1102,7 +1102,7 @@ Value must be %list%, if specified
 ### svelte_options_invalid_customelement
 
 ```
-"customElement" must be a string literal defining a valid custom element name or an object of the form { tag?: string; shadow?: "open" | "none"; props?: { [key: string]: { attribute?: string; reflect?: boolean; type: .. } } }
+"customElement" must be a string literal defining a valid custom element name or an object of the form { tag?: string; shadow?: "open" | "none" | `ShadowRootInit`; props?: { [key: string]: { attribute?: string; reflect?: boolean; type: .. } } }
 ```
 
 ### svelte_options_invalid_customelement_props
@@ -1114,9 +1114,11 @@ Value must be %list%, if specified
 ### svelte_options_invalid_customelement_shadow
 
 ```
-"shadow" must be either "open" or "none"
+"shadow" must be either "open", "none" or `ShadowRootInit` object.
 ```
 
+See https://developer.mozilla.org/en-US/docs/Web/API/Element/attachShadow#options for more information on valid shadow root constructor options
+
 ### svelte_options_invalid_tagname
 
 ```
diff --git a/packages/svelte/elements.d.ts b/packages/svelte/elements.d.ts
index 4dba2c5c32..fa74124472 100644
--- a/packages/svelte/elements.d.ts
+++ b/packages/svelte/elements.d.ts
@@ -2062,7 +2062,7 @@ export interface SvelteHTMLElements {
 			| undefined
 			| {
 					tag?: string;
-					shadow?: 'open' | 'none' | undefined;
+					shadow?: 'open' | 'none' | ShadowRootInit | undefined;
 					props?:
 						| Record<
 								string,
diff --git a/packages/svelte/messages/compile-errors/template.md b/packages/svelte/messages/compile-errors/template.md
index 086b9e8b25..bd07955bc3 100644
--- a/packages/svelte/messages/compile-errors/template.md
+++ b/packages/svelte/messages/compile-errors/template.md
@@ -411,7 +411,7 @@ HTML restricts where certain elements can appear. In case of a violation the bro
 
 ## svelte_options_invalid_customelement
 
-> "customElement" must be a string literal defining a valid custom element name or an object of the form { tag?: string; shadow?: "open" | "none"; props?: { [key: string]: { attribute?: string; reflect?: boolean; type: .. } } }
+> "customElement" must be a string literal defining a valid custom element name or an object of the form { tag?: string; shadow?: "open" | "none" | `ShadowRootInit`; props?: { [key: string]: { attribute?: string; reflect?: boolean; type: .. } } }
 
 ## svelte_options_invalid_customelement_props
 
@@ -419,7 +419,9 @@ HTML restricts where certain elements can appear. In case of a violation the bro
 
 ## svelte_options_invalid_customelement_shadow
 
-> "shadow" must be either "open" or "none"
+> "shadow" must be either "open", "none" or `ShadowRootInit` object.
+
+See https://developer.mozilla.org/en-US/docs/Web/API/Element/attachShadow#options for more information on valid shadow root constructor options
 
 ## svelte_options_invalid_tagname
 
diff --git a/packages/svelte/src/compiler/errors.js b/packages/svelte/src/compiler/errors.js
index 990b643e68..3997dbec32 100644
--- a/packages/svelte/src/compiler/errors.js
+++ b/packages/svelte/src/compiler/errors.js
@@ -1550,12 +1550,12 @@ export function svelte_options_invalid_attribute_value(node, list) {
 }
 
 /**
- * "customElement" must be a string literal defining a valid custom element name or an object of the form { tag?: string; shadow?: "open" | "none"; props?: { [key: string]: { attribute?: string; reflect?: boolean; type: .. } } }
+ * "customElement" must be a string literal defining a valid custom element name or an object of the form { tag?: string; shadow?: "open" | "none" | `ShadowRootInit`; props?: { [key: string]: { attribute?: string; reflect?: boolean; type: .. } } }
  * @param {null | number | NodeLike} node
  * @returns {never}
  */
 export function svelte_options_invalid_customelement(node) {
-	e(node, 'svelte_options_invalid_customelement', `"customElement" must be a string literal defining a valid custom element name or an object of the form { tag?: string; shadow?: "open" | "none"; props?: { [key: string]: { attribute?: string; reflect?: boolean; type: .. } } }\nhttps://svelte.dev/e/svelte_options_invalid_customelement`);
+	e(node, 'svelte_options_invalid_customelement', `"customElement" must be a string literal defining a valid custom element name or an object of the form { tag?: string; shadow?: "open" | "none" | \`ShadowRootInit\`; props?: { [key: string]: { attribute?: string; reflect?: boolean; type: .. } } }\nhttps://svelte.dev/e/svelte_options_invalid_customelement`);
 }
 
 /**
@@ -1568,12 +1568,12 @@ export function svelte_options_invalid_customelement_props(node) {
 }
 
 /**
- * "shadow" must be either "open" or "none"
+ * "shadow" must be either "open", "none" or `ShadowRootInit` object.
  * @param {null | number | NodeLike} node
  * @returns {never}
  */
 export function svelte_options_invalid_customelement_shadow(node) {
-	e(node, 'svelte_options_invalid_customelement_shadow', `"shadow" must be either "open" or "none"\nhttps://svelte.dev/e/svelte_options_invalid_customelement_shadow`);
+	e(node, 'svelte_options_invalid_customelement_shadow', `"shadow" must be either "open", "none" or \`ShadowRootInit\` object.\nhttps://svelte.dev/e/svelte_options_invalid_customelement_shadow`);
 }
 
 /**
diff --git a/packages/svelte/src/compiler/phases/1-parse/read/options.js b/packages/svelte/src/compiler/phases/1-parse/read/options.js
index a36e101468..2677fb3b61 100644
--- a/packages/svelte/src/compiler/phases/1-parse/read/options.js
+++ b/packages/svelte/src/compiler/phases/1-parse/read/options.js
@@ -133,11 +133,13 @@ export default function read_options(node) {
 
 				const shadow = properties.find(([name]) => name === 'shadow')?.[1];
 				if (shadow) {
-					const shadowdom = shadow?.value;
-					if (shadowdom !== 'open' && shadowdom !== 'none') {
-						e.svelte_options_invalid_customelement_shadow(shadow);
+					if (shadow.type === 'Literal' && (shadow.value === 'open' || shadow.value === 'none')) {
+						ce.shadow = shadow.value;
+					} else if (shadow.type === 'ObjectExpression') {
+						ce.shadow = shadow;
+					} else {
+						e.svelte_options_invalid_customelement_shadow(attribute);
 					}
-					ce.shadow = shadowdom;
 				}
 
 				const extend = properties.find(([name]) => name === 'extend')?.[1];
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 fc202f1bc2..d5ce3caaa9 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
@@ -638,7 +638,16 @@ export function client_component(analysis, options) {
 		const accessors_str = b.array(
 			analysis.exports.map(({ name, alias }) => b.literal(alias ?? name))
 		);
-		const use_shadow_dom = typeof ce === 'boolean' || ce.shadow !== 'none' ? true : false;
+
+		/** @type {ESTree.ObjectExpression | undefined} */
+		let shadow_root_init;
+		if (typeof ce === 'boolean' || ce.shadow === 'open' || ce.shadow === undefined) {
+			shadow_root_init = b.object([b.init('mode', b.literal('open'))]);
+		} else if (ce.shadow === 'none') {
+			shadow_root_init = undefined;
+		} else {
+			shadow_root_init = ce.shadow;
+		}
 
 		const create_ce = b.call(
 			'$.create_custom_element',
@@ -646,7 +655,7 @@ export function client_component(analysis, options) {
 			b.object(props_str),
 			slots_str,
 			accessors_str,
-			b.literal(use_shadow_dom),
+			shadow_root_init,
 			/** @type {any} */ (typeof ce !== 'boolean' ? ce.extend : undefined)
 		);
 
diff --git a/packages/svelte/src/compiler/types/template.d.ts b/packages/svelte/src/compiler/types/template.d.ts
index b529a2dda9..b924406d0f 100644
--- a/packages/svelte/src/compiler/types/template.d.ts
+++ b/packages/svelte/src/compiler/types/template.d.ts
@@ -87,7 +87,7 @@ export namespace AST {
 		css?: 'injected';
 		customElement?: {
 			tag?: string;
-			shadow?: 'open' | 'none';
+			shadow?: 'open' | 'none' | ObjectExpression | undefined;
 			props?: Record<
 				string,
 				{
diff --git a/packages/svelte/src/internal/client/dom/elements/custom-element.js b/packages/svelte/src/internal/client/dom/elements/custom-element.js
index 2d118bfab3..40d3d68ec0 100644
--- a/packages/svelte/src/internal/client/dom/elements/custom-element.js
+++ b/packages/svelte/src/internal/client/dom/elements/custom-element.js
@@ -35,18 +35,23 @@ if (typeof HTMLElement === 'function') {
 		$$l_u = new Map();
 		/** @type {any} The managed render effect for reflecting attributes */
 		$$me;
+		/** @type {ShadowRoot | null} The ShadowRoot of the custom element */
+		$$shadowRoot = null;
 
 		/**
 		 * @param {*} $$componentCtor
 		 * @param {*} $$slots
-		 * @param {*} use_shadow_dom
+		 * @param {ShadowRootInit | undefined} shadow_root_init
 		 */
-		constructor($$componentCtor, $$slots, use_shadow_dom) {
+		constructor($$componentCtor, $$slots, shadow_root_init) {
 			super();
 			this.$$ctor = $$componentCtor;
 			this.$$s = $$slots;
-			if (use_shadow_dom) {
-				this.attachShadow({ mode: 'open' });
+
+			if (shadow_root_init) {
+				// We need to store the reference to shadow root, because `closed` shadow root cannot be
+				// accessed with `this.shadowRoot`.
+				this.$$shadowRoot = this.attachShadow(shadow_root_init);
 			}
 		}
 
@@ -136,7 +141,7 @@ if (typeof HTMLElement === 'function') {
 				}
 				this.$$c = createClassComponent({
 					component: this.$$ctor,
-					target: this.shadowRoot || this,
+					target: this.$$shadowRoot || this,
 					props: {
 						...this.$$d,
 						$$slots,
@@ -277,7 +282,7 @@ function get_custom_elements_slots(element) {
  * @param {Record<string, CustomElementPropDefinition>} props_definition  The props to observe
  * @param {string[]} slots  The slots to create
  * @param {string[]} exports  Explicitly exported values, other than props
- * @param {boolean} use_shadow_dom  Whether to use shadow DOM
+ * @param {ShadowRootInit | undefined} shadow_root_init  Options passed to shadow DOM constructor
  * @param {(ce: new () => HTMLElement) => new () => HTMLElement} [extend]
  */
 export function create_custom_element(
@@ -285,12 +290,12 @@ export function create_custom_element(
 	props_definition,
 	slots,
 	exports,
-	use_shadow_dom,
+	shadow_root_init,
 	extend
 ) {
 	let Class = class extends SvelteElement {
 		constructor() {
-			super(Component, slots, use_shadow_dom);
+			super(Component, slots, shadow_root_init);
 			this.$$p_d = props_definition;
 		}
 		static get observedAttributes() {
diff --git a/packages/svelte/tests/runtime-browser/custom-elements-samples/closed-shadow-dom/_config.js b/packages/svelte/tests/runtime-browser/custom-elements-samples/closed-shadow-dom/_config.js
new file mode 100644
index 0000000000..9e09967dab
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/custom-elements-samples/closed-shadow-dom/_config.js
@@ -0,0 +1,13 @@
+import { test } from '../../assert';
+const tick = () => Promise.resolve();
+
+export default test({
+	async test({ assert, target }) {
+		target.innerHTML = '<custom-element></custom-element>';
+		await tick();
+
+		const el = target.querySelector('custom-element');
+
+		assert.equal(el.shadowRoot, null);
+	}
+});
diff --git a/packages/svelte/tests/runtime-browser/custom-elements-samples/closed-shadow-dom/main.svelte b/packages/svelte/tests/runtime-browser/custom-elements-samples/closed-shadow-dom/main.svelte
new file mode 100644
index 0000000000..93744481b3
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/custom-elements-samples/closed-shadow-dom/main.svelte
@@ -0,0 +1,3 @@
+<svelte:options customElement={{ tag: "custom-element", shadow: { mode: 'closed' } }} />
+
+<h1>Hello world!</h1>
diff --git a/packages/svelte/tests/runtime-browser/custom-elements-samples/shadow-root-init-options/_config.js b/packages/svelte/tests/runtime-browser/custom-elements-samples/shadow-root-init-options/_config.js
new file mode 100644
index 0000000000..106d27929e
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/custom-elements-samples/shadow-root-init-options/_config.js
@@ -0,0 +1,18 @@
+import { test } from '../../assert';
+const tick = () => Promise.resolve();
+
+export default test({
+	async test({ assert, target }) {
+		target.innerHTML = '<custom-element></custom-element>';
+		await tick();
+
+		/** @type {ShadowRoot} */
+		const shadowRoot = target.querySelector('custom-element').shadowRoot;
+
+		assert.equal(shadowRoot.mode, 'open');
+		assert.equal(shadowRoot.clonable, true);
+		assert.equal(shadowRoot.delegatesFocus, true);
+		assert.equal(shadowRoot.serializable, true);
+		assert.equal(shadowRoot.slotAssignment, 'manual');
+	}
+});
diff --git a/packages/svelte/tests/runtime-browser/custom-elements-samples/shadow-root-init-options/main.svelte b/packages/svelte/tests/runtime-browser/custom-elements-samples/shadow-root-init-options/main.svelte
new file mode 100644
index 0000000000..25d69d7ef9
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/custom-elements-samples/shadow-root-init-options/main.svelte
@@ -0,0 +1,14 @@
+<svelte:options
+	customElement={{
+		tag: 'custom-element',
+		shadow: {
+			mode: 'open',
+			clonable: true,
+			delegatesFocus: true,
+			serializable: true,
+			slotAssignment: 'manual',
+		},
+	}}
+/>
+
+<h1>Hello world!</h1>
diff --git a/packages/svelte/tests/validator/samples/tag-non-string/errors.json b/packages/svelte/tests/validator/samples/tag-non-string/errors.json
index 71f8df4d00..5473e18b7d 100644
--- a/packages/svelte/tests/validator/samples/tag-non-string/errors.json
+++ b/packages/svelte/tests/validator/samples/tag-non-string/errors.json
@@ -1,7 +1,7 @@
 [
 	{
 		"code": "svelte_options_invalid_customelement",
-		"message": "\"customElement\" must be a string literal defining a valid custom element name or an object of the form { tag?: string; shadow?: \"open\" | \"none\"; props?: { [key: string]: { attribute?: string; reflect?: boolean; type: .. } } }",
+		"message": "\"customElement\" must be a string literal defining a valid custom element name or an object of the form { tag?: string; shadow?: \"open\" | \"none\" | `ShadowRootInit`; props?: { [key: string]: { attribute?: string; reflect?: boolean; type: .. } } }",
 		"start": {
 			"line": 1,
 			"column": 16
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index 128de134ed..730e0ff655 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -1234,7 +1234,7 @@ declare module 'svelte/compiler' {
 			css?: 'injected';
 			customElement?: {
 				tag?: string;
-				shadow?: 'open' | 'none';
+				shadow?: 'open' | 'none' | ObjectExpression | undefined;
 				props?: Record<
 					string,
 					{

From 975a5ec60a8541bcc02197d38cd2b5e4765c6b07 Mon Sep 17 00:00:00 2001
From: "Dominik G." <dominik.goepel@gmx.de>
Date: Wed, 28 Jan 2026 01:38:24 +0100
Subject: [PATCH 087/142] fix invalid negative values in sourcemap column
 indexes (#17167)

* add check for negative idx to sourcemaps test

* fix: format

* Update packages/svelte/tests/sourcemaps/test.ts

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 packages/svelte/tests/sourcemaps/test.ts | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/packages/svelte/tests/sourcemaps/test.ts b/packages/svelte/tests/sourcemaps/test.ts
index c654258b34..0ac0e6f905 100644
--- a/packages/svelte/tests/sourcemaps/test.ts
+++ b/packages/svelte/tests/sourcemaps/test.ts
@@ -96,6 +96,20 @@ const { test, run } = suite<SourcemapTest>(async (config, cwd) => {
 
 		const decoded = decode(map.mappings);
 
+		/*
+		Decoded sourcemap mappings contain absolute line/column numbers.
+		Negative values are invalid and can cause errors in downstream processing
+		*/
+		for (let l = 0; l < decoded.length; l++) {
+			for (let m of decoded[l]) {
+				if (m.some((i) => i < 0)) {
+					throw new Error(
+						`Invalid mapping with negative value ${JSON.stringify(m)} at line ${l} of the decoded mappings of ${info} sourcemap\n${JSON.stringify(map)}`
+					);
+				}
+			}
+		}
+
 		try {
 			for (let entry of entries) {
 				entry = typeof entry === 'string' ? { str: entry } : entry;

From 123c48d38d1a0cab292a5c98da048fb886a6005b Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Wed, 28 Jan 2026 03:15:42 +0100
Subject: [PATCH 088/142] chore: give download.js script ability to download
 from stackblitz/github (#17549)

* chore: give download.js script ability to download from stackblitz/github

...including a very simple SvelteKit-detection + transformation to simple Svelte (or error if not possible)

* format
---
 playgrounds/sandbox/scripts/download.js | 666 ++++++++++++++++++++++--
 1 file changed, 630 insertions(+), 36 deletions(-)

diff --git a/playgrounds/sandbox/scripts/download.js b/playgrounds/sandbox/scripts/download.js
index b5eaeaa8f5..b0bad54e73 100644
--- a/playgrounds/sandbox/scripts/download.js
+++ b/playgrounds/sandbox/scripts/download.js
@@ -1,6 +1,8 @@
 import fs from 'node:fs';
 import path from 'node:path';
 import { parseArgs } from 'node:util';
+import { execSync } from 'node:child_process';
+import { chromium } from 'playwright';
 
 const { values, positionals } = parseArgs({
 	options: {
@@ -19,53 +21,639 @@ if (!url_arg) {
 	process.exit(1);
 }
 
-/** @type {URL} */
-let url;
+const base_dir = import.meta.dirname;
 
-try {
-	url = new URL(url_arg);
-} catch (e) {
-	console.error(`${url_arg} is not a URL`);
-	process.exit(1);
+/**
+ * Check if the argument is a local directory path
+ * @param {string} arg
+ * @returns {boolean}
+ */
+function is_local_directory(arg) {
+	try {
+		return fs.existsSync(arg) && fs.statSync(arg).isDirectory();
+	} catch {
+		return false;
+	}
 }
 
-if (url.origin !== 'https://svelte.dev' || !url.pathname.startsWith('/playground/')) {
-	console.error(`${url_arg} is not a Svelte playground URL`);
-	process.exit(1);
+// Check if it's a local directory first (before URL parsing)
+const is_local = is_local_directory(url_arg);
+
+/** @type {URL | null} */
+let url = null;
+
+if (!is_local) {
+	try {
+		url = new URL(url_arg);
+	} catch (e) {
+		console.error(`${url_arg} is not a valid URL or local directory`);
+		process.exit(1);
+	}
 }
 
-let files;
+/**
+ * Check if URL is a GitHub repository URL
+ * @param {URL} url
+ * @returns {boolean}
+ */
+function is_github_url(url) {
+	return url.hostname === 'github.com' && url.pathname.split('/').filter(Boolean).length >= 2;
+}
+
+/**
+ * Check if URL is a StackBlitz GitHub project URL
+ * @param {URL} url
+ * @returns {boolean}
+ */
+function is_stackblitz_github_url(url) {
+	return url.hostname === 'stackblitz.com' && url.pathname.startsWith('/github/');
+}
+
+/**
+ * Check if URL is a StackBlitz edit project URL (non-GitHub)
+ * @param {URL} url
+ * @returns {boolean}
+ */
+function is_stackblitz_edit_url(url) {
+	return url.hostname === 'stackblitz.com' && url.pathname.startsWith('/edit/');
+}
+
+/**
+ * Extract GitHub repo info from a StackBlitz GitHub URL
+ * @param {URL} url
+ * @returns {{ owner: string, repo: string, path?: string }}
+ */
+function extract_stackblitz_github_info(url) {
+	// URL format: /github/owner/repo or /github/owner/repo/tree/branch/path
+	const parts = url.pathname.split('/').filter(Boolean);
+	// parts[0] = 'github', parts[1] = owner, parts[2] = repo
+	return {
+		owner: parts[1],
+		repo: parts[2],
+		path: parts.length > 3 ? parts.slice(3).join('/') : undefined
+	};
+}
+
+/**
+ * Clone a GitHub repository to a temporary directory
+ * @param {URL} url
+ * @param {string} target_dir
+ */
+function clone_github_repo(url, target_dir) {
+	// Extract repo URL (handle both https://github.com/owner/repo and https://github.com/owner/repo/tree/branch/path)
+	const parts = url.pathname.split('/').filter(Boolean);
+	const owner = parts[0];
+	const repo = parts[1];
+	const repo_url = `https://github.com/${owner}/${repo}.git`;
+
+	console.log(`Cloning ${repo_url}...`);
+	execSync(`git clone --depth 1 ${repo_url} "${target_dir}"`, { stdio: 'inherit' });
+}
+
+/**
+ * Clone a StackBlitz GitHub project to a temporary directory
+ * (Converts to regular GitHub clone)
+ * @param {URL} url
+ * @param {string} target_dir
+ */
+function clone_stackblitz_github_project(url, target_dir) {
+	const info = extract_stackblitz_github_info(url);
+	const repo_url = `https://github.com/${info.owner}/${info.repo}.git`;
 
-if (url.hash.length > 1) {
-	const decoded = atob(url.hash.slice(1).replaceAll('-', '+').replaceAll('_', '/'));
-	// putting it directly into the blob gives a corrupted file
-	const u8 = new Uint8Array(decoded.length);
-	for (let i = 0; i < decoded.length; i++) {
-		u8[i] = decoded.charCodeAt(i);
+	console.log(`StackBlitz GitHub project detected, cloning from ${repo_url}...`);
+
+	execSync(`git clone --depth 1 ${repo_url} "${target_dir}"`, { stdio: 'inherit' });
+}
+
+/**
+ * Download a StackBlitz project using browser automation
+ * @param {URL} url
+ * @param {string} target_dir
+ */
+async function download_stackblitz_project(url, target_dir) {
+	console.log(`Downloading StackBlitz project via browser automation...`);
+	console.log(`URL: ${url.href}`);
+
+	const browser = await chromium.launch({ headless: true });
+	const context = await browser.newContext({ acceptDownloads: true });
+	const page = await context.newPage();
+
+	try {
+		// Navigate to the StackBlitz project
+		console.log('Loading StackBlitz project (this may take a moment)...');
+		await page.goto(url.href, { waitUntil: 'domcontentloaded', timeout: 20000 });
+
+		// Set up download handler
+		const downloadPromise = page.waitForEvent('download', { timeout: 30000 });
+		await page.locator('button[aria-label*="Download Project" i]', { timeout: 30000 }).click();
+		console.log('Triggering download...');
+
+		// Wait for the download to start
+		const download = await downloadPromise;
+
+		// Save the downloaded file
+		const zip_path = path.join(target_dir, 'project.zip');
+		await download.saveAs(zip_path);
+
+		console.log('Download complete, extracting...');
+
+		// Extract the zip file
+		if (process.platform === 'win32') {
+			execSync(
+				`powershell -Command "Expand-Archive -Path '${zip_path}' -DestinationPath '${target_dir}' -Force"`,
+				{ stdio: 'inherit' }
+			);
+		} else {
+			execSync(`unzip -o "${zip_path}" -d "${target_dir}"`, { stdio: 'inherit' });
+		}
+
+		// Remove the zip file
+		fs.unlinkSync(zip_path);
+
+		// Check if files were extracted into a subdirectory
+		const entries = fs.readdirSync(target_dir);
+		if (entries.length === 1) {
+			const subdir = path.join(target_dir, entries[0]);
+			if (fs.statSync(subdir).isDirectory()) {
+				// Move files from subdirectory to target_dir
+				const subentries = fs.readdirSync(subdir);
+				for (const entry of subentries) {
+					fs.renameSync(path.join(subdir, entry), path.join(target_dir, entry));
+				}
+				fs.rmdirSync(subdir);
+			}
+		}
+
+		console.log('StackBlitz project downloaded successfully');
+	} finally {
+		await browser.close();
 	}
-	const stream = new Blob([u8]).stream().pipeThrough(new DecompressionStream('gzip'));
-	const json = await new Response(stream).text();
+}
 
-	files = JSON.parse(json).files;
-} else {
-	const id = url.pathname.split('/')[2];
-	const response = await fetch(`https://svelte.dev/playground/api/${id}.json`);
-
-	files = (await response.json()).components.map((data) => {
-		const basename = `${data.name}.${data.type}`;
-
-		return {
-			type: 'file',
-			name: basename,
-			basename,
-			contents: data.source,
-			text: true
-		};
+/**
+ * Recursively get all files in a directory
+ * @param {string} dir
+ * @param {string} base
+ * @returns {Array<{path: string, name: string, contents: string}>}
+ */
+function get_all_files(dir, base = '') {
+	/** @type {Array<{path: string, name: string, contents: string}>} */
+	const results = [];
+
+	if (!fs.existsSync(dir)) return results;
+
+	const entries = fs.readdirSync(dir, { withFileTypes: true });
+
+	for (const entry of entries) {
+		const full_path = path.join(dir, entry.name);
+		const relative_path = base ? `${base}/${entry.name}` : entry.name;
+
+		if (entry.isDirectory()) {
+			// Skip node_modules, .git, etc.
+			if (['node_modules', '.git', '.svelte-kit', 'build', 'dist'].includes(entry.name)) {
+				continue;
+			}
+			results.push(...get_all_files(full_path, relative_path));
+		} else if (
+			entry.name.endsWith('.svelte') ||
+			entry.name.endsWith('.js') ||
+			entry.name.endsWith('.ts')
+		) {
+			results.push({
+				path: relative_path,
+				name: entry.name,
+				contents: fs.readFileSync(full_path, 'utf-8')
+			});
+		}
+	}
+
+	return results;
+}
+
+/**
+ * Detect project type from files
+ * @param {Array<{path: string, name: string, contents: string}>} files
+ * @returns {{ type: 'sveltekit' | 'vite', has_app_imports: boolean, has_page_svelte: boolean }}
+ */
+function detect_project_type(files) {
+	let has_app_imports = false;
+	let has_page_svelte = false;
+
+	for (const file of files) {
+		// Check for $app/* imports
+		if (/from\s+['"](\$app\/[^'"]+)['"]/.test(file.contents)) {
+			has_app_imports = true;
+		}
+		// Check for +page.svelte or +layout.svelte
+		if (file.name === '+page.svelte' || file.name === '+layout.svelte') {
+			has_page_svelte = true;
+		}
+	}
+
+	return {
+		type: has_page_svelte ? 'sveltekit' : 'vite',
+		has_app_imports,
+		has_page_svelte
+	};
+}
+
+/**
+ * Convert a route path to a PascalCase component name
+ * @param {string} route_path - e.g., "about", "blog/post"
+ * @returns {string} - e.g., "About", "BlogPost"
+ */
+function route_to_component_name(route_path) {
+	if (!route_path || route_path === '') return 'Page';
+
+	return route_path
+		.split('/')
+		.map((part) => part.charAt(0).toUpperCase() + part.slice(1))
+		.join('');
+}
+
+/**
+ * Transform $lib/* imports to relative imports (flattened)
+ * @param {string} content
+ * @returns {string}
+ */
+function transform_lib_imports(content) {
+	// Replace $lib/ imports with relative paths to flattened files
+	return content.replace(/from\s+['"](\$lib\/[^'"]+)['"]/g, (match, import_path) => {
+		// Get just the filename from the lib path
+		const lib_path = import_path.replace('$lib/', '');
+		const filename = path.basename(lib_path);
+		return `from './${filename}'`;
 	});
 }
 
-const base_dir = import.meta.dirname;
+/**
+ * Build the route tree from SvelteKit files
+ * @param {Array<{path: string, name: string, contents: string}>} files
+ * @param {string} routes_prefix - e.g., "src/routes"
+ * @returns {Map<string, {layout?: {path: string, contents: string}, page?: {path: string, contents: string}}>}
+ */
+function build_route_tree(files, routes_prefix) {
+	/** @type {Map<string, {layout?: {path: string, contents: string}, page?: {path: string, contents: string}}>} */
+	const routes = new Map();
 
+	for (const file of files) {
+		if (!file.path.startsWith(routes_prefix)) continue;
+
+		const relative_to_routes = file.path.slice(routes_prefix.length + 1); // +1 for the slash
+		const dir = path.dirname(relative_to_routes);
+		const route_key = dir === '.' ? '' : dir;
+
+		if (!routes.has(route_key)) {
+			routes.set(route_key, {});
+		}
+
+		const route = routes.get(route_key);
+		if (file.name === '+layout.svelte') {
+			route.layout = { path: file.path, contents: file.contents };
+		} else if (file.name === '+page.svelte') {
+			route.page = { path: file.path, contents: file.contents };
+		}
+	}
+
+	return routes;
+}
+
+/**
+ * Get child routes of a given route
+ * @param {Map<string, any>} routes
+ * @param {string} parent_route
+ * @returns {string[]}
+ */
+function get_child_routes(routes, parent_route) {
+	const children = [];
+	for (const route of routes.keys()) {
+		if (route === parent_route) continue;
+
+		const parent_prefix = parent_route === '' ? '' : parent_route + '/';
+		if (
+			parent_route === ''
+				? !route.includes('/')
+				: route.startsWith(parent_prefix) && !route.slice(parent_prefix.length).includes('/')
+		) {
+			children.push(route);
+		}
+	}
+	return children;
+}
+
+/**
+ * Transform a layout file's content to replace {@render children()} with a component
+ * @param {string} content
+ * @param {string} child_component_name
+ * @returns {string}
+ */
+function transform_layout_content(content, child_component_name) {
+	// Add import for the child component at the top of the script
+	const import_statement = `import ${child_component_name} from './${child_component_name}.svelte';`;
+
+	// Check if there's already a script tag
+	if (/<script[^>]*>/.test(content)) {
+		// Add import after the opening script tag
+		content = content.replace(/(<script[^>]*>)/, `$1\n\t${import_statement}`);
+	} else {
+		// Add a new script block at the beginning
+		content = `<script>\n\t${import_statement}\n</script>\n\n${content}`;
+	}
+
+	// Replace {@render children()} or {@render children?.()} with the component
+	content = content.replace(/\{@render\s+children\?\.\(\)\}/g, `<${child_component_name} />`);
+	content = content.replace(/\{@render\s+children\(\)\}/g, `<${child_component_name} />`);
+
+	return content;
+}
+
+/**
+ * Convert a SvelteKit project to plain Svelte components
+ * @param {string} repo_dir
+ * @returns {Array<{name: string, contents: string}>}
+ */
+function convert_sveltekit_project(repo_dir) {
+	const all_files = get_all_files(repo_dir);
+	/** @type {Array<{name: string, contents: string}>} */
+	const output_files = [];
+
+	// Find the routes directory
+	let routes_prefix = '';
+	for (const file of all_files) {
+		if (file.path.includes('src/routes/')) {
+			routes_prefix = 'src/routes';
+			break;
+		}
+	}
+
+	if (!routes_prefix) {
+		console.error('Could not find src/routes directory');
+		process.exit(1);
+	}
+
+	// Build route tree
+	const routes = build_route_tree(all_files, routes_prefix);
+
+	// Process lib files - flatten them to root level
+	const lib_files = all_files.filter((f) => f.path.startsWith('src/lib/'));
+	for (const file of lib_files) {
+		// Flatten to just the filename
+		const new_path = path.basename(file.path);
+		let contents = file.contents;
+		contents = transform_lib_imports(contents);
+		output_files.push({
+			name: new_path,
+			contents
+		});
+	}
+
+	// Sort routes by depth (deepest first) so we can process children before parents
+	const sorted_routes = [...routes.keys()].sort((a, b) => {
+		const depth_a = a === '' ? 0 : a.split('/').length;
+		const depth_b = b === '' ? 0 : b.split('/').length;
+		return depth_b - depth_a;
+	});
+
+	// Map to store what component each route renders
+	/** @type {Map<string, string>} */
+	const route_component_map = new Map();
+
+	// First pass: convert all pages
+	for (const route_key of sorted_routes) {
+		const route = routes.get(route_key);
+		if (route?.page) {
+			const component_name = route_to_component_name(route_key);
+			let contents = route.page.contents;
+			contents = transform_lib_imports(contents);
+			output_files.push({
+				name: `${component_name}.svelte`,
+				contents
+			});
+			// If no layout, this is what the route renders
+			if (!route.layout) {
+				route_component_map.set(route_key, component_name);
+			}
+		}
+	}
+
+	// Second pass: convert layouts (from deepest to root)
+	for (const route_key of sorted_routes) {
+		const route = routes.get(route_key);
+		if (route?.layout) {
+			const is_root = route_key === '';
+			const component_name = is_root ? 'App' : route_to_component_name(route_key) + 'Layout';
+
+			// Determine what child component this layout should render
+			let child_component = '';
+
+			// Check if there's a page at this route level
+			if (route.page) {
+				child_component = route_to_component_name(route_key);
+			} else {
+				// Find child routes that have content
+				const children = get_child_routes(routes, route_key);
+				if (children.length > 0) {
+					// Use the first child's component (or its layout if it has one)
+					const first_child = children[0];
+					child_component =
+						route_component_map.get(first_child) || route_to_component_name(first_child);
+				}
+			}
+
+			let contents = route.layout.contents;
+			contents = transform_lib_imports(contents);
+
+			if (child_component) {
+				contents = transform_layout_content(contents, child_component);
+			} else {
+				// No child, just remove {@render children()} or {@render children?.()}
+				contents = contents.replace(/\{@render\s+children\?\.\(\)\}/g, '<!-- no child content -->');
+				contents = contents.replace(/\{@render\s+children\(\)\}/g, '<!-- no child content -->');
+			}
+
+			output_files.push({
+				name: `${component_name}.svelte`,
+				contents
+			});
+
+			// This route now renders the layout
+			route_component_map.set(route_key, component_name);
+		}
+	}
+
+	// If there's no root layout but there's a root page, rename it to App.svelte
+	if (!routes.get('')?.layout && routes.get('')?.page) {
+		const page_index = output_files.findIndex((f) => f.name === 'Page.svelte');
+		if (page_index !== -1) {
+			output_files[page_index].name = 'App.svelte';
+		}
+	}
+
+	// If there's no App.svelte yet, create one that imports the first available component
+	if (!output_files.some((f) => f.name === 'App.svelte')) {
+		const first_component = output_files.find(
+			(f) => f.name.endsWith('.svelte') && !f.name.includes('/')
+		);
+		if (first_component) {
+			const comp_name = first_component.name.replace('.svelte', '');
+			output_files.push({
+				name: 'App.svelte',
+				contents: `<script>\n\timport ${comp_name} from './${first_component.name}';\n</script>\n\n<${comp_name} />\n`
+			});
+		}
+	}
+
+	return output_files;
+}
+
+/**
+ * Convert a regular Vite+Svelte project
+ * @param {string} repo_dir
+ * @returns {Array<{name: string, contents: string}>}
+ */
+function convert_vite_project(repo_dir) {
+	const all_files = get_all_files(repo_dir);
+	/** @type {Array<{name: string, contents: string}>} */
+	const output_files = [];
+
+	// Find src directory
+	const src_files = all_files.filter(
+		(f) =>
+			f.path.startsWith('src/') &&
+			(f.name.endsWith('.svelte') || f.name.endsWith('.js') || f.name.endsWith('.ts'))
+	);
+
+	for (const file of src_files) {
+		// Flatten all files to root level (just the filename)
+		const new_path = path.basename(file.path);
+
+		let contents = file.contents;
+		contents = transform_lib_imports(contents);
+
+		output_files.push({
+			name: new_path,
+			contents
+		});
+	}
+
+	return output_files;
+}
+
+/**
+ * Process a local or cloned directory
+ * @param {string} dir_path
+ * @returns {Array<{name: string, contents: string}>}
+ */
+function process_directory(dir_path) {
+	const all_files = get_all_files(dir_path);
+	const project_info = detect_project_type(all_files);
+
+	console.log(`Detected project type: ${project_info.type}`);
+
+	// Check for $app/* imports
+	if (project_info.has_app_imports) {
+		console.error('Error: This SvelteKit project uses $app/* imports which cannot be converted.');
+		console.error('The playground does not support SvelteKit runtime features.');
+		process.exit(1);
+	}
+
+	// Convert based on project type
+	if (project_info.type === 'sveltekit') {
+		console.log('Converting SvelteKit project to plain Svelte...');
+		return convert_sveltekit_project(dir_path);
+	} else {
+		console.log('Processing Vite+Svelte project...');
+		return convert_vite_project(dir_path);
+	}
+}
+
+/**
+ * Reset a directory so it exists and is empty
+ * @param {string} dir_path
+ */
+/**
+ * Create a temporary directory, run an action, and always clean up
+ * @param {string} base_dir
+ * @param {(dir: string) => void | Promise<void>} action
+ */
+async function with_tmp_dir(base_dir, action) {
+	const tmp_dir = path.join(base_dir, '.tmp-repo');
+
+	try {
+		if (fs.existsSync(tmp_dir)) {
+			fs.rmSync(tmp_dir, { recursive: true, force: true });
+		}
+		fs.mkdirSync(tmp_dir, { recursive: true });
+		await action(tmp_dir);
+	} finally {
+		if (fs.existsSync(tmp_dir)) {
+			fs.rmSync(tmp_dir, { recursive: true, force: true });
+		}
+	}
+}
+
+// Main logic
+let files;
+
+// Check if it's a local directory first (before URL parsing)
+if (is_local) {
+	console.log(`Processing local directory: ${url_arg}`);
+	files = process_directory(url_arg);
+} else if (url && is_github_url(url)) {
+	// GitHub repository handling
+	await with_tmp_dir(base_dir, (tmp_dir) => {
+		clone_github_repo(url, tmp_dir);
+		files = process_directory(tmp_dir);
+	});
+} else if (url && is_stackblitz_github_url(url)) {
+	// StackBlitz GitHub project handling (redirect to GitHub clone)
+	await with_tmp_dir(base_dir, (tmp_dir) => {
+		clone_stackblitz_github_project(url, tmp_dir);
+		files = process_directory(tmp_dir);
+	});
+} else if (url && is_stackblitz_edit_url(url)) {
+	// StackBlitz edit URLs - use browser automation to download
+	await with_tmp_dir(base_dir, async (tmp_dir) => {
+		await download_stackblitz_project(url, tmp_dir);
+		files = process_directory(tmp_dir);
+	});
+} else if (url && url.origin === 'https://svelte.dev' && url.pathname.startsWith('/playground/')) {
+	// Svelte playground URL handling (existing logic)
+	if (url.hash.length > 1) {
+		const decoded = atob(url.hash.slice(1).replaceAll('-', '+').replaceAll('_', '/'));
+		// putting it directly into the blob gives a corrupted file
+		const u8 = new Uint8Array(decoded.length);
+		for (let i = 0; i < decoded.length; i++) {
+			u8[i] = decoded.charCodeAt(i);
+		}
+		const stream = new Blob([u8]).stream().pipeThrough(new DecompressionStream('gzip'));
+		const json = await new Response(stream).text();
+
+		files = JSON.parse(json).files;
+	} else {
+		const id = url.pathname.split('/')[2];
+		const response = await fetch(`https://svelte.dev/playground/api/${id}.json`);
+
+		files = (await response.json()).components.map((data) => {
+			const basename = `${data.name}.${data.type}`;
+
+			return {
+				type: 'file',
+				name: basename,
+				basename,
+				contents: data.source,
+				text: true
+			};
+		});
+	}
+} else {
+	console.error(
+		`${url_arg} is not a supported URL (Svelte playground, GitHub repository, or StackBlitz project)`
+	);
+	process.exit(1);
+}
+
+// Output files
 if (create_test_name) {
 	const test_parts = create_test_name.split('/').filter(Boolean);
 
@@ -111,8 +699,14 @@ export default test({
 });
 `
 	);
+
+	console.log(`Test created at ${output_dir}`);
 } else {
 	for (const file of files) {
-		fs.writeFileSync(path.join(base_dir, '..', 'src', file.name), file.contents);
+		const output_path = path.join(base_dir, '..', 'src', file.name);
+		fs.mkdirSync(path.dirname(output_path), { recursive: true });
+		fs.writeFileSync(output_path, file.contents);
 	}
+
+	console.log(`Files written to ${path.join(base_dir, '..', 'src')}`);
 }

From a66f453b56400f0b687e02d0dace150d148d0ec8 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Tue, 27 Jan 2026 22:16:53 -0500
Subject: [PATCH 089/142] docs: tweaking getting started instructions (#17566)

---
 documentation/docs/01-introduction/02-getting-started.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/documentation/docs/01-introduction/02-getting-started.md b/documentation/docs/01-introduction/02-getting-started.md
index 519959a0b1..ecb1055443 100644
--- a/documentation/docs/01-introduction/02-getting-started.md
+++ b/documentation/docs/01-introduction/02-getting-started.md
@@ -15,7 +15,7 @@ Don't worry if you don't know Svelte yet! You can ignore all the nice features S
 
 ## Alternatives to SvelteKit
 
-You can also use Svelte directly with Vite by running `npm create vite@latest` and selecting the `svelte` option. With this, `npm run build` will generate HTML, JS, and CSS files inside the `dist` directory using [vite-plugin-svelte](https://github.com/sveltejs/vite-plugin-svelte). In most cases, you will probably need to [choose a routing library](/packages#routing) as well.
+You can also use Svelte directly with Vite via [vite-plugin-svelte](https://github.com/sveltejs/vite-plugin-svelte) by running `npm create vite@latest` and selecting the `svelte` option (or, if working with an existing project, adding the plugin to your `vite.config.js` file). With this, `npm run build` will generate HTML, JS, and CSS files inside the `dist` directory. In most cases, you will probably need to [choose a routing library](/packages#routing) as well.
 
 >[!NOTE] Vite is often used in standalone mode to build [single page apps (SPAs)](../kit/glossary#SPA), which you can also [build with SvelteKit](../kit/single-page-apps).
 
@@ -25,7 +25,7 @@ There are also [plugins for other bundlers](/packages#bundler-plugins), but we r
 
 The Svelte team maintains a [VS Code extension](https://marketplace.visualstudio.com/items?itemName=svelte.svelte-vscode), and there are integrations with various other [editors](https://sveltesociety.dev/collection/editor-support-c85c080efc292a34) and tools as well.
 
-You can also check your code from the command line using [`sv check`](https://github.com/sveltejs/cli).
+You can also check your code from the command line using [`npx sv check`](https://svelte.dev/docs/cli/sv-check).
 
 
 ## Getting help

From 06e6ef83b801a3ca014af4629abad76ac2d35eef Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Tue, 27 Jan 2026 22:44:26 -0500
Subject: [PATCH 090/142] failing test (#12791)

---
 .../tests/hydration/samples/safari-borking-2/Child.svelte   | 6 ++++++
 .../tests/hydration/samples/safari-borking-2/_config.js     | 5 +++++
 .../tests/hydration/samples/safari-borking-2/_override.html | 1 +
 .../tests/hydration/samples/safari-borking-2/main.svelte    | 6 ++++++
 4 files changed, 18 insertions(+)
 create mode 100644 packages/svelte/tests/hydration/samples/safari-borking-2/Child.svelte
 create mode 100644 packages/svelte/tests/hydration/samples/safari-borking-2/_config.js
 create mode 100644 packages/svelte/tests/hydration/samples/safari-borking-2/_override.html
 create mode 100644 packages/svelte/tests/hydration/samples/safari-borking-2/main.svelte

diff --git a/packages/svelte/tests/hydration/samples/safari-borking-2/Child.svelte b/packages/svelte/tests/hydration/samples/safari-borking-2/Child.svelte
new file mode 100644
index 0000000000..a62bd4ec90
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/safari-borking-2/Child.svelte
@@ -0,0 +1,6 @@
+<script>
+	const message = `call +636-555-3226 now`;
+</script>
+
+<hr />
+{message}
diff --git a/packages/svelte/tests/hydration/samples/safari-borking-2/_config.js b/packages/svelte/tests/hydration/samples/safari-borking-2/_config.js
new file mode 100644
index 0000000000..cf22ff2c85
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/safari-borking-2/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	expect_hydration_error: true
+});
diff --git a/packages/svelte/tests/hydration/samples/safari-borking-2/_override.html b/packages/svelte/tests/hydration/samples/safari-borking-2/_override.html
new file mode 100644
index 0000000000..17ec01970a
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/safari-borking-2/_override.html
@@ -0,0 +1 @@
+<!--[--><hr> call <a href="tel:+636-555-3226">+636-555-3226</a> now<!----> <p>42</p><!--]-->
diff --git a/packages/svelte/tests/hydration/samples/safari-borking-2/main.svelte b/packages/svelte/tests/hydration/samples/safari-borking-2/main.svelte
new file mode 100644
index 0000000000..daa25067ec
--- /dev/null
+++ b/packages/svelte/tests/hydration/samples/safari-borking-2/main.svelte
@@ -0,0 +1,6 @@
+<script>
+	import Child from './Child.svelte';
+</script>
+
+<Child />
+<p>{40 + 2}</p>

From 16fec7207a39d6f913e1ec32fbe5b2a6f2db838f Mon Sep 17 00:00:00 2001
From: PandaMan <joewartson757@gmail.com>
Date: Thu, 29 Jan 2026 00:17:38 +0800
Subject: [PATCH 091/142] fix: make onintrostart respect delay parameter
 (#17567)

* fix: make onintrostart respect delay parameter

Fixes #14009

The onintrostart event now fires after the delay period completes,
rather than immediately when the transition is initiated. This ensures
that the event accurately reflects when the intro animation actually
starts.

Changes:
- Added on_start callback parameter to animate() function
- Dispatch introstart event after delay animation finishes
- Handle edge case where duration is 0 but delay > 0

* fix: format code with prettier

* add (failing) tests

* fix

* changeset

* missed a spot

* fix

---------

Co-authored-by: Miner <miner@example.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/sweet-rings-watch.md               |  5 +++
 .../client/dom/elements/transitions.js        |  9 +++---
 .../transition-delayed-events-css/_config.js  | 32 +++++++++++++++++++
 .../transition-delayed-events-css/main.svelte | 23 +++++++++++++
 .../transition-delayed-events-js/_config.js   | 32 +++++++++++++++++++
 .../transition-delayed-events-js/main.svelte  | 23 +++++++++++++
 6 files changed, 119 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/sweet-rings-watch.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/transition-delayed-events-css/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/transition-delayed-events-css/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/transition-delayed-events-js/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/transition-delayed-events-js/main.svelte

diff --git a/.changeset/sweet-rings-watch.md b/.changeset/sweet-rings-watch.md
new file mode 100644
index 0000000000..8ce11b2672
--- /dev/null
+++ b/.changeset/sweet-rings-watch.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: fire introstart/outrostart events after delay, if specified
diff --git a/packages/svelte/src/internal/client/dom/elements/transitions.js b/packages/svelte/src/internal/client/dom/elements/transitions.js
index e9f0953df7..170b40780a 100644
--- a/packages/svelte/src/internal/client/dom/elements/transitions.js
+++ b/packages/svelte/src/internal/client/dom/elements/transitions.js
@@ -239,8 +239,6 @@ export function transition(flags, element, get_fn, get_params) {
 				intro?.abort();
 			}
 
-			dispatch_event(element, 'introstart');
-
 			intro = animate(element, get_options(), outro, 1, () => {
 				dispatch_event(element, 'introend');
 
@@ -260,8 +258,6 @@ export function transition(flags, element, get_fn, get_params) {
 
 			element.inert = true;
 
-			dispatch_event(element, 'outrostart');
-
 			outro = animate(element, get_options(), intro, 0, () => {
 				dispatch_event(element, 'outroend');
 				fn?.();
@@ -345,7 +341,8 @@ function animate(element, options, counterpart, t2, on_finish) {
 
 	counterpart?.deactivate();
 
-	if (!options?.duration) {
+	if (!options?.duration && !options?.delay) {
+		dispatch_event(element, is_intro ? 'introstart' : 'outrostart');
 		on_finish();
 
 		return {
@@ -385,6 +382,8 @@ function animate(element, options, counterpart, t2, on_finish) {
 		// remove dummy animation from the stack to prevent conflict with main animation
 		animation.cancel();
 
+		dispatch_event(element, is_intro ? 'introstart' : 'outrostart');
+
 		// for bidirectional transitions, we start from the current position,
 		// rather than doing a full intro/outro
 		var t1 = counterpart?.t() ?? 1 - t2;
diff --git a/packages/svelte/tests/runtime-runes/samples/transition-delayed-events-css/_config.js b/packages/svelte/tests/runtime-runes/samples/transition-delayed-events-css/_config.js
new file mode 100644
index 0000000000..36daefa3b7
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/transition-delayed-events-css/_config.js
@@ -0,0 +1,32 @@
+import { flushSync } from '../../../../src/index-client.js';
+import { test } from '../../test';
+
+export default test({
+	test({ assert, raf, target, logs }) {
+		const [btn] = target.querySelectorAll('button');
+
+		// in
+		flushSync(() => btn.click());
+		assert.deepEqual(logs, []);
+		raf.tick(1);
+		assert.deepEqual(logs, []);
+
+		raf.tick(100);
+		assert.deepEqual(logs, ['introstart']);
+
+		raf.tick(200);
+		assert.deepEqual(logs, ['introstart', 'introend']);
+
+		// out
+		flushSync(() => btn.click());
+		assert.deepEqual(logs, ['introstart', 'introend']);
+		raf.tick(201);
+		assert.deepEqual(logs, ['introstart', 'introend']);
+
+		raf.tick(300);
+		assert.deepEqual(logs, ['introstart', 'introend', 'outrostart']);
+
+		raf.tick(400);
+		assert.deepEqual(logs, ['introstart', 'introend', 'outrostart', 'outroend']);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/transition-delayed-events-css/main.svelte b/packages/svelte/tests/runtime-runes/samples/transition-delayed-events-css/main.svelte
new file mode 100644
index 0000000000..cd91790c17
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/transition-delayed-events-css/main.svelte
@@ -0,0 +1,23 @@
+<script>
+	function fade(_) {
+		return {
+			delay: 100,
+			duration: 100,
+			css: (t) => `opacity: ${t}`
+		};
+	}
+
+	let visible = $state(false);
+</script>
+
+<button onclick={() => (visible = !visible)}>toggle</button>
+
+{#if visible}
+	<p
+		transition:fade
+		onintrostart={() => console.log('introstart')}
+		onintroend={() => console.log('introend')}
+		onoutrostart={() => console.log('outrostart')}
+		onoutroend={() => console.log('outroend')}
+	>delayed fade</p>
+{/if}
diff --git a/packages/svelte/tests/runtime-runes/samples/transition-delayed-events-js/_config.js b/packages/svelte/tests/runtime-runes/samples/transition-delayed-events-js/_config.js
new file mode 100644
index 0000000000..36daefa3b7
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/transition-delayed-events-js/_config.js
@@ -0,0 +1,32 @@
+import { flushSync } from '../../../../src/index-client.js';
+import { test } from '../../test';
+
+export default test({
+	test({ assert, raf, target, logs }) {
+		const [btn] = target.querySelectorAll('button');
+
+		// in
+		flushSync(() => btn.click());
+		assert.deepEqual(logs, []);
+		raf.tick(1);
+		assert.deepEqual(logs, []);
+
+		raf.tick(100);
+		assert.deepEqual(logs, ['introstart']);
+
+		raf.tick(200);
+		assert.deepEqual(logs, ['introstart', 'introend']);
+
+		// out
+		flushSync(() => btn.click());
+		assert.deepEqual(logs, ['introstart', 'introend']);
+		raf.tick(201);
+		assert.deepEqual(logs, ['introstart', 'introend']);
+
+		raf.tick(300);
+		assert.deepEqual(logs, ['introstart', 'introend', 'outrostart']);
+
+		raf.tick(400);
+		assert.deepEqual(logs, ['introstart', 'introend', 'outrostart', 'outroend']);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/transition-delayed-events-js/main.svelte b/packages/svelte/tests/runtime-runes/samples/transition-delayed-events-js/main.svelte
new file mode 100644
index 0000000000..c7167aa8c7
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/transition-delayed-events-js/main.svelte
@@ -0,0 +1,23 @@
+<script>
+	function fade(node) {
+		return {
+			delay: 100,
+			duration: 100,
+			tick: (t) => node.style.opacity = t
+		};
+	}
+
+	let visible = $state(false);
+</script>
+
+<button onclick={() => (visible = !visible)}>toggle</button>
+
+{#if visible}
+	<p
+		transition:fade
+		onintrostart={() => console.log('introstart')}
+		onintroend={() => console.log('introend')}
+		onoutrostart={() => console.log('outrostart')}
+		onoutroend={() => console.log('outroend')}
+	>delayed fade</p>
+{/if}

From 08448c501b97a4617171ee9db69c60aa3bd0bbcc Mon Sep 17 00:00:00 2001
From: GiantDragon9090 <102870250+GiantDragon9090@users.noreply.github.com>
Date: Wed, 28 Jan 2026 09:55:32 -0800
Subject: [PATCH 092/142] docs: update FAQ to mention SvelteKit hash-based
 routing support (#17546)

Fixes #14919

Co-authored-by: Gittensor Miner <miner@gittensor.io>
---
 documentation/docs/07-misc/99-faq.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/documentation/docs/07-misc/99-faq.md b/documentation/docs/07-misc/99-faq.md
index 4c1d19a262..035629e5ae 100644
--- a/documentation/docs/07-misc/99-faq.md
+++ b/documentation/docs/07-misc/99-faq.md
@@ -91,7 +91,7 @@ Some resources for getting started with testing:
 
 ## Is there a router?
 
-The official routing library is [SvelteKit](/docs/kit). SvelteKit provides a filesystem router, server-side rendering (SSR), and hot module reloading (HMR) in one easy-to-use package. It shares similarities with Next.js for React and Nuxt.js for Vue.
+The official routing library is [SvelteKit](/docs/kit). SvelteKit provides a filesystem router, server-side rendering (SSR), and hot module reloading (HMR) in one easy-to-use package. It shares similarities with Next.js for React and Nuxt.js for Vue. SvelteKit also supports hash-based routing for client-side applications.
 
 However, you can use any router library. A sampling of available routers are highlighted [on the packages page](/packages#routing).
 

From 3256a75b547d9ee440be0c2b51865b31cb6d9c88 Mon Sep 17 00:00:00 2001
From: Razin Shafayet <sumonislamk29@gmail.com>
Date: Wed, 28 Jan 2026 23:56:17 +0600
Subject: [PATCH 093/142] fix: ignore popover elements in
 a11y_consider_explicit_label check (#17367)

* fix: ignore popover elements in a11y_consider_explicit_label check

* chore: add changeset

* Apply suggestions from code review

* Apply suggestions from code review

* fix

---------

Co-authored-by: Rich Harris <hello@rich-harris.dev>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/shaggy-phones-laugh.md                  |  5 +++++
 .../phases/2-analyze/visitors/shared/a11y/index.js |  4 ++++
 .../samples/a11y-popover-label/input.svelte        |  3 +++
 .../samples/a11y-popover-label/warnings.json       | 14 ++++++++++++++
 4 files changed, 26 insertions(+)
 create mode 100644 .changeset/shaggy-phones-laugh.md
 create mode 100644 packages/svelte/tests/validator/samples/a11y-popover-label/input.svelte
 create mode 100644 packages/svelte/tests/validator/samples/a11y-popover-label/warnings.json

diff --git a/.changeset/shaggy-phones-laugh.md b/.changeset/shaggy-phones-laugh.md
new file mode 100644
index 0000000000..8cb711491b
--- /dev/null
+++ b/.changeset/shaggy-phones-laugh.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: disregard `popover` elements when determining whether an element has content
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 50b107d068..f5f4982ed2 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
@@ -824,6 +824,10 @@ function has_content(element) {
 		}
 
 		if (node.type === 'RegularElement' || node.type === 'SvelteElement') {
+			if (node.attributes.some((a) => a.type === 'Attribute' && a.name === 'popover')) {
+				continue;
+			}
+
 			if (
 				node.name === 'img' &&
 				node.attributes.some((node) => node.type === 'Attribute' && node.name === 'alt')
diff --git a/packages/svelte/tests/validator/samples/a11y-popover-label/input.svelte b/packages/svelte/tests/validator/samples/a11y-popover-label/input.svelte
new file mode 100644
index 0000000000..6fafa0a10c
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/a11y-popover-label/input.svelte
@@ -0,0 +1,3 @@
+<button interestfor="my-hint">
+	<div id="my-hint" popover="hint">hello</div>
+</button>
\ No newline at end of file
diff --git a/packages/svelte/tests/validator/samples/a11y-popover-label/warnings.json b/packages/svelte/tests/validator/samples/a11y-popover-label/warnings.json
new file mode 100644
index 0000000000..f5fd09c89d
--- /dev/null
+++ b/packages/svelte/tests/validator/samples/a11y-popover-label/warnings.json
@@ -0,0 +1,14 @@
+[
+	{
+		"code": "a11y_consider_explicit_label",
+		"message": "Buttons and links should either contain text or have an `aria-label`, `aria-labelledby` or `title` attribute",
+		"start": {
+			"line": 1,
+			"column": 0
+		},
+		"end": {
+			"line": 3,
+			"column": 9
+		}
+	}
+]

From 2b4253f33271dbe8024cfb3946964e4cd6df0315 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 28 Jan 2026 13:40:10 -0500
Subject: [PATCH 094/142] chore: allow sandbox to 'download' from tests
 (#17576)

---
 playgrounds/sandbox/scripts/download.js | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/playgrounds/sandbox/scripts/download.js b/playgrounds/sandbox/scripts/download.js
index b0bad54e73..e3c862cb61 100644
--- a/playgrounds/sandbox/scripts/download.js
+++ b/playgrounds/sandbox/scripts/download.js
@@ -39,10 +39,14 @@ function is_local_directory(arg) {
 // Check if it's a local directory first (before URL parsing)
 const is_local = is_local_directory(url_arg);
 
+const resolved_test_path = ['runtime-runes', 'runtime-legacy']
+	.map((d) => path.resolve(`${base_dir}/../../../packages/svelte/tests/${d}/samples/${url_arg}`))
+	.find(fs.existsSync);
+
 /** @type {URL | null} */
 let url = null;
 
-if (!is_local) {
+if (!is_local && !resolved_test_path) {
 	try {
 		url = new URL(url_arg);
 	} catch (e) {
@@ -599,6 +603,17 @@ let files;
 if (is_local) {
 	console.log(`Processing local directory: ${url_arg}`);
 	files = process_directory(url_arg);
+} else if (resolved_test_path) {
+	// Copy files from test
+	console.log(`Processing test ${url_arg}`);
+	files = get_all_files(resolved_test_path)
+		.filter((file) => !file.path.includes('_'))
+		.map((file) => {
+			return {
+				name: file.name === 'main.svelte' ? 'App.svelte' : file.name,
+				contents: file.contents
+			};
+		});
 } else if (url && is_github_url(url)) {
 	// GitHub repository handling
 	await with_tmp_dir(base_dir, (tmp_dir) => {

From 37cd40d2e5d1868810b87705287eedd4f0370bdd Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 28 Jan 2026 14:23:27 -0500
Subject: [PATCH 095/142] fix: more conservative assignment_value_stale
 warnings (#17574)

---
 .changeset/plain-dancers-double.md            |  5 ++++
 .../client/visitors/AssignmentExpression.js   |  5 +++-
 packages/svelte/src/compiler/phases/scope.js  |  8 ++++++
 .../svelte/src/internal/client/dev/assign.js  |  3 ++-
 .../_config.js                                | 25 ++++++++-----------
 .../main.svelte                               | 11 ++++++++
 6 files changed, 40 insertions(+), 17 deletions(-)
 create mode 100644 .changeset/plain-dancers-double.md

diff --git a/.changeset/plain-dancers-double.md b/.changeset/plain-dancers-double.md
new file mode 100644
index 0000000000..ab47b8e4c7
--- /dev/null
+++ b/.changeset/plain-dancers-double.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: more conservative assignment_value_stale warnings
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 731569aaae..0f6a619357 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
@@ -162,7 +162,10 @@ function build_assignment(operator, left, right, context) {
 	// will be pushed to. we do this by transforming it to something like
 	// `$.assign_nullish(object, 'items', [])`
 	let should_transform =
-		dev && path.at(-1) !== 'ExpressionStatement' && is_non_coercive_operator(operator);
+		dev &&
+		path.at(-1) !== 'ExpressionStatement' &&
+		is_non_coercive_operator(operator) &&
+		!context.state.scope.evaluate(right).is_primitive;
 
 	// special case — ignore `onclick={() => (...)}`
 	if (
diff --git a/packages/svelte/src/compiler/phases/scope.js b/packages/svelte/src/compiler/phases/scope.js
index 2a0c76f756..52efd93210 100644
--- a/packages/svelte/src/compiler/phases/scope.js
+++ b/packages/svelte/src/compiler/phases/scope.js
@@ -228,6 +228,13 @@ class Evaluation {
 	 */
 	is_number = true;
 
+	/**
+	 * True if the value is known to be a primitive
+	 * @readonly
+	 * @type {boolean}
+	 */
+	is_primitive = true;
+
 	/**
 	 * True if the value is known to be a function
 	 * @readonly
@@ -577,6 +584,7 @@ class Evaluation {
 
 			if (value === UNKNOWN) {
 				this.has_unknown = true;
+				this.is_primitive = false;
 			}
 		}
 
diff --git a/packages/svelte/src/internal/client/dev/assign.js b/packages/svelte/src/internal/client/dev/assign.js
index d9ef7497d5..3b48e736b5 100644
--- a/packages/svelte/src/internal/client/dev/assign.js
+++ b/packages/svelte/src/internal/client/dev/assign.js
@@ -1,3 +1,4 @@
+import { STATE_SYMBOL } from '#client/constants';
 import { sanitize_location } from '../../../utils.js';
 import { untrack } from '../runtime.js';
 import * as w from '../warnings.js';
@@ -10,7 +11,7 @@ import * as w from '../warnings.js';
  * @param {string} location
  */
 function compare(a, b, property, location) {
-	if (a !== b) {
+	if (a !== b && typeof b === 'object' && STATE_SYMBOL in b) {
 		w.assignment_value_stale(property, /** @type {string} */ (sanitize_location(location)));
 	}
 
diff --git a/packages/svelte/tests/runtime-runes/samples/proxy-coercive-assignment-warning/_config.js b/packages/svelte/tests/runtime-runes/samples/proxy-coercive-assignment-warning/_config.js
index 4462f492fa..2ff2634822 100644
--- a/packages/svelte/tests/runtime-runes/samples/proxy-coercive-assignment-warning/_config.js
+++ b/packages/svelte/tests/runtime-runes/samples/proxy-coercive-assignment-warning/_config.js
@@ -6,31 +6,26 @@ export default test({
 		dev: true
 	},
 
-	html: `<button>items: null</button> <div>x</div> <input type="checkbox" value="1"><input type="checkbox" value="2"><input>`,
-
 	test({ assert, target, warnings }) {
-		const btn = target.querySelector('button');
-		ok(btn);
+		const [button1, button2, button3] = target.querySelectorAll('button');
+		ok(button1);
 
-		flushSync(() => btn.click());
-		assert.htmlEqual(
-			target.innerHTML,
-			`<button>items: []</button> <div>x</div> <input type="checkbox" value="1"><input type="checkbox" value="2"><input>`
-		);
+		flushSync(() => button1.click());
+		assert.htmlEqual(button1.innerHTML, `items: []`);
 
-		flushSync(() => btn.click());
-		assert.htmlEqual(
-			target.innerHTML,
-			`<button>items: [0]</button> <div>x</div> <input type="checkbox" value="1"><input type="checkbox" value="2"><input>`
-		);
+		flushSync(() => button1.click());
+		assert.htmlEqual(button1.innerHTML, `items: [0]`);
 
 		const input = target.querySelector('input');
 		ok(input);
 		input.checked = true;
 		flushSync(() => input.dispatchEvent(new Event('change', { bubbles: true })));
 
+		flushSync(() => button2.click());
+		flushSync(() => button3.click());
+
 		assert.deepEqual(warnings, [
-			'Assignment to `items` property (main.svelte:9:24) will evaluate to the right-hand side, not the value of `items` following the assignment. This may result in unexpected behaviour.'
+			'Assignment to `items` property (main.svelte:17:24) will evaluate to the right-hand side, not the value of `items` following the assignment. This may result in unexpected behaviour.'
 		]);
 	}
 });
diff --git a/packages/svelte/tests/runtime-runes/samples/proxy-coercive-assignment-warning/main.svelte b/packages/svelte/tests/runtime-runes/samples/proxy-coercive-assignment-warning/main.svelte
index a79fe873b7..02320a3128 100644
--- a/packages/svelte/tests/runtime-runes/samples/proxy-coercive-assignment-warning/main.svelte
+++ b/packages/svelte/tests/runtime-runes/samples/proxy-coercive-assignment-warning/main.svelte
@@ -1,9 +1,17 @@
  <script>
 	import Test from './Test.svelte';
 
+	let { opacity = 0.5 } = $props();
+
 	let entries = $state([]);
 	let object = $state({ items: null, group: [] });
 	let elementFunBind = $state();
+
+	// should omit $.assign via static analysis
+	const fixed = (node) => node.style.opacity = 0.5;
+
+	// should use $.assign, but it should not warn
+	const unknown = (node) => node.style.opacity = opacity;
 </script>
 
 <button onclick={() => (object.items ??= []).push(object.items.length)}>
@@ -23,3 +31,6 @@
 	<input bind:this={() => {}, (e) => (context.element = e)} />
 {/snippet}
 {@render funBind({ set element(e) { elementFunBind = e } })}
+
+<button onclick={(e) => (fixed(e.currentTarget))}>change opacity (fixed)</button>
+<button onclick={(e) => (unknown(e.currentTarget))}>change opacity (unknown)</button>

From ece2e83eb9d0e2a97d7db50d41f68ce2edfb697d Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 28 Jan 2026 16:09:32 -0500
Subject: [PATCH 096/142] fix: increment signal versions when discarding forks
 (#17577)

* fix: always update an UNINITIALIZED derived on read

Co-authored-by: David Roizenman <hmnd@users.noreply.github.com>

* obsolete comments

* rename test

* add tests, fix

* revert

* Update .changeset/vast-hornets-draw.md

---------

Co-authored-by: David Roizenman <hmnd@users.noreply.github.com>
---
 .changeset/vast-hornets-draw.md               |  5 +++
 .../src/internal/client/reactivity/batch.js   |  7 ++++
 .../fork-derived-uncached-1/_config.js        | 40 +++++++++++++++++++
 .../fork-derived-uncached-1/main.svelte       | 23 +++++++++++
 .../fork-derived-uncached-2/_config.js        | 38 ++++++++++++++++++
 .../fork-derived-uncached-2/main.svelte       | 23 +++++++++++
 .../fork-derived-uncached-3/_config.js        | 32 +++++++++++++++
 .../fork-derived-uncached-3/main.svelte       | 23 +++++++++++
 8 files changed, 191 insertions(+)
 create mode 100644 .changeset/vast-hornets-draw.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-1/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-1/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-2/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-2/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-3/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-3/main.svelte

diff --git a/.changeset/vast-hornets-draw.md b/.changeset/vast-hornets-draw.md
new file mode 100644
index 0000000000..256439e9da
--- /dev/null
+++ b/.changeset/vast-hornets-draw.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: increment signal versions when discarding forks
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 134ebe53a2..d82f965541 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -972,6 +972,13 @@ export function fork(fn) {
 			await settled;
 		},
 		discard: () => {
+			// cause any MAYBE_DIRTY deriveds to update
+			// if they depend on things thath changed
+			// inside the discarded fork
+			for (var source of batch.current.keys()) {
+				source.wv = increment_write_version();
+			}
+
 			if (!committed && batches.has(batch)) {
 				batches.delete(batch);
 				batch.discard();
diff --git a/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-1/_config.js b/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-1/_config.js
new file mode 100644
index 0000000000..fb50ceb9b1
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-1/_config.js
@@ -0,0 +1,40 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	skip_no_async: true,
+	async test({ assert, target }) {
+		const [fork, toggle, increment] = target.querySelectorAll('button');
+
+		// derived is first evaluated in block effect, then discarded
+		flushSync(() => fork.click());
+
+		// should not throw "Cannot convert a Symbol value to a string" due to cached UNINITIALIZED from first fork
+		flushSync(() => fork.click());
+
+		// should not reflect the temporary change to `clicks` inside the fork
+		flushSync(() => toggle.click());
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>fork</button>
+				<button>toggle</button>
+				<button>clicks: 0</button>
+				<p>0</p>
+			`
+		);
+
+		flushSync(() => increment.click());
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>fork</button>
+				<button>toggle</button>
+				<button>clicks: 1</button>
+				<p>2</p>
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-1/main.svelte b/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-1/main.svelte
new file mode 100644
index 0000000000..08ebaba25a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-1/main.svelte
@@ -0,0 +1,23 @@
+<script>
+	import { fork } from "svelte";
+
+	let clicks = $state(0);
+	let show = $state(false);
+	const derived = $derived(clicks * 2);
+</script>
+
+<button onclick={() => {
+	fork(() => {
+		clicks += 1;
+		show = true;
+	}).discard();
+}}>fork</button>
+
+<button onclick={() => show = !show}>toggle</button>
+
+<button onclick={() => clicks++}>clicks: {clicks}</button>
+
+{#if show}
+	<p>{derived}</p>
+{/if}
+
diff --git a/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-2/_config.js b/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-2/_config.js
new file mode 100644
index 0000000000..21ab140fc0
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-2/_config.js
@@ -0,0 +1,38 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	skip_no_async: true,
+	async test({ assert, target }) {
+		const [fork, toggle, increment] = target.querySelectorAll('button');
+
+		// derived is first evaluated in block effect, then discarded
+		flushSync(() => fork.click());
+
+		// should not reflect the temporary change to `clicks` inside the fork
+		// or throw "Cannot convert a Symbol value to a string" due to cached UNINITIALIZED
+		flushSync(() => toggle.click());
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>fork</button>
+				<button>toggle</button>
+				<button>clicks: 0</button>
+				<p>0</p>
+			`
+		);
+
+		flushSync(() => increment.click());
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>fork</button>
+				<button>toggle</button>
+				<button>clicks: 1</button>
+				<p>2</p>
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-2/main.svelte b/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-2/main.svelte
new file mode 100644
index 0000000000..08ebaba25a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-2/main.svelte
@@ -0,0 +1,23 @@
+<script>
+	import { fork } from "svelte";
+
+	let clicks = $state(0);
+	let show = $state(false);
+	const derived = $derived(clicks * 2);
+</script>
+
+<button onclick={() => {
+	fork(() => {
+		clicks += 1;
+		show = true;
+	}).discard();
+}}>fork</button>
+
+<button onclick={() => show = !show}>toggle</button>
+
+<button onclick={() => clicks++}>clicks: {clicks}</button>
+
+{#if show}
+	<p>{derived}</p>
+{/if}
+
diff --git a/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-3/_config.js b/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-3/_config.js
new file mode 100644
index 0000000000..4827aa99f3
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-3/_config.js
@@ -0,0 +1,32 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	skip_no_async: true,
+	async test({ assert, target }) {
+		const [fork, toggle, increment] = target.querySelectorAll('button');
+
+		// initialize derived by showing it
+		flushSync(() => toggle.click());
+		flushSync(() => toggle.click());
+
+		// increment clicks
+		flushSync(() => increment.click());
+
+		// update derived, but without writing to `derived.v`
+		flushSync(() => fork.click());
+
+		// show derived
+		flushSync(() => toggle.click());
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>fork</button>
+				<button>toggle</button>
+				<button>clicks: 1</button>
+				<p>2</p>
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-3/main.svelte b/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-3/main.svelte
new file mode 100644
index 0000000000..08ebaba25a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/fork-derived-uncached-3/main.svelte
@@ -0,0 +1,23 @@
+<script>
+	import { fork } from "svelte";
+
+	let clicks = $state(0);
+	let show = $state(false);
+	const derived = $derived(clicks * 2);
+</script>
+
+<button onclick={() => {
+	fork(() => {
+		clicks += 1;
+		show = true;
+	}).discard();
+}}>fork</button>
+
+<button onclick={() => show = !show}>toggle</button>
+
+<button onclick={() => clicks++}>clicks: {clicks}</button>
+
+{#if show}
+	<p>{derived}</p>
+{/if}
+

From 3608b3c8691cf855ec2cdeb623b904d2b95eddcc Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 28 Jan 2026 16:59:40 -0500
Subject: [PATCH 097/142] fix: preserve old dependencies when updating reaction
 inside fork (#17579)

Co-authored-by: David Roizenman <hmnd@users.noreply.github.com>
---
 .changeset/fuzzy-spies-love.md                |  5 ++++
 .../svelte/src/internal/client/runtime.js     | 18 ++++++++++---
 .../_config.js                                | 25 +++++++++++++++++
 .../main.svelte                               | 27 +++++++++++++++++++
 4 files changed, 72 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/fuzzy-spies-love.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/fork-derived-dependency-rollback/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/fork-derived-dependency-rollback/main.svelte

diff --git a/.changeset/fuzzy-spies-love.md b/.changeset/fuzzy-spies-love.md
new file mode 100644
index 0000000000..9129d986bc
--- /dev/null
+++ b/.changeset/fuzzy-spies-love.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: preserve old dependencies when updating reaction inside fork
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 2075081f96..70eeabb789 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -43,7 +43,13 @@ import {
 	set_dev_current_component_function,
 	set_dev_stack
 } from './context.js';
-import { Batch, batch_values, flushSync, schedule_effect } from './reactivity/batch.js';
+import {
+	Batch,
+	batch_values,
+	current_batch,
+	flushSync,
+	schedule_effect
+} from './reactivity/batch.js';
 import { handle_error } from './error-handling.js';
 import { UNINITIALIZED } from '../../constants.js';
 import { captured_signals } from './legacy.js';
@@ -249,10 +255,16 @@ export function update_reaction(reaction) {
 		var result = fn();
 		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;
 
-			remove_reactions(reaction, skipped_deps);
+			if (!is_fork) {
+				remove_reactions(reaction, skipped_deps);
+			}
 
 			if (deps !== null && skipped_deps > 0) {
 				deps.length = skipped_deps + new_deps.length;
@@ -268,7 +280,7 @@ export function update_reaction(reaction) {
 					(deps[i].reactions ??= []).push(reaction);
 				}
 			}
-		} else if (deps !== null && skipped_deps < deps.length) {
+		} else if (!is_fork && deps !== null && skipped_deps < deps.length) {
 			remove_reactions(reaction, skipped_deps);
 			deps.length = skipped_deps;
 		}
diff --git a/packages/svelte/tests/runtime-runes/samples/fork-derived-dependency-rollback/_config.js b/packages/svelte/tests/runtime-runes/samples/fork-derived-dependency-rollback/_config.js
new file mode 100644
index 0000000000..c5db69f7d4
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/fork-derived-dependency-rollback/_config.js
@@ -0,0 +1,25 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	skip_no_async: true,
+	async test({ assert, target }) {
+		const [fork_btn, _toggle_btn, inc_count_1_btn] = target.querySelectorAll('button');
+		const p = /** @type {HTMLElement} */ (target.querySelector('p'));
+
+		assert.equal(p.textContent, '0');
+
+		// Trigger derived to re-evaluate during fork and switch to tracking count_2
+		flushSync(() => {
+			fork_btn.click();
+		});
+
+		assert.equal(p.textContent, '0');
+
+		flushSync(() => {
+			inc_count_1_btn.click();
+		});
+
+		assert.equal(p.textContent, '1');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/fork-derived-dependency-rollback/main.svelte b/packages/svelte/tests/runtime-runes/samples/fork-derived-dependency-rollback/main.svelte
new file mode 100644
index 0000000000..800c82b56b
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/fork-derived-dependency-rollback/main.svelte
@@ -0,0 +1,27 @@
+<script>
+	import { fork } from 'svelte';
+
+	let show_count_1 = $state(true);
+	let count_1 = $state(0);
+	let count_2 = $state(0);
+
+	const count = $derived(show_count_1 ? count_1 : count_2);
+</script>
+
+<!-- This if block causes the derived to execute during the fork, switching its dependency
+     away from count_1 and over to count_2. After discard, count_1 should still be tracked. -->
+{#if count}
+{/if}
+
+<button onclick={() => {
+	const f = fork(() => {
+		show_count_1 = !show_count_1;
+	});
+	f.discard();
+}}>fork toggle</button>
+
+<button onclick={() => show_count_1 = !show_count_1}>toggle</button>
+<button onclick={() => count_1++}>increment count 1</button>
+<button onclick={() => count_2++}>increment count 2</button>
+
+<p>{count}</p>

From 1c131f11ca6a49d1ffba07d3d02bb895c668ef00 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 28 Jan 2026 19:00:13 -0500
Subject: [PATCH 098/142] fix: reset effects inside skipped branches (#17581)

* fix: prevent reactivity loss during fork

fixes #17197, fixes #17304, fixes #17301, fixes #17309

* add samples

* add changeset

* fix var casing in tests

* don't remove reactions during fork

* add sample for derived dep tracking in fork

* fix sample type check error

* set derived.v on first eval in fork

* add sample for derived.v remaining UNINITIALIZED

* lost current_batch import in runtime.js

* Delete how

* Update packages/svelte/src/internal/client/reactivity/deriveds.js

* delete test in favour of #17577

* extract runtime.js changes into separate PR

* alternative approach

* revert

* clear skipped branches when deferring

* fix

* fix

* changeset

* rename test

* update test

* unused test

---------

Co-authored-by: David Roizenman <david@hmnd.io>
Co-authored-by: Paolo Ricciuti <ricciutipaolo@gmail.com>
Co-authored-by: Tee Ming <chewteeming01@gmail.com>
---
 .changeset/common-boats-travel.md             |  5 ++++
 .../src/internal/client/reactivity/batch.js   | 24 +++++++++++++++++++
 .../samples/async-skipped-branch/_config.js   | 21 ++++++++++++++++
 .../samples/async-skipped-branch/main.svelte  | 22 +++++++++++++++++
 4 files changed, 72 insertions(+)
 create mode 100644 .changeset/common-boats-travel.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-skipped-branch/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-skipped-branch/main.svelte

diff --git a/.changeset/common-boats-travel.md b/.changeset/common-boats-travel.md
new file mode 100644
index 0000000000..bd3012bbf2
--- /dev/null
+++ b/.changeset/common-boats-travel.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: reset effects inside skipped branches
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index d82f965541..2b6e84889b 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -171,6 +171,10 @@ export class Batch {
 		if (this.is_deferred()) {
 			this.#defer_effects(render_effects);
 			this.#defer_effects(effects);
+
+			for (const e of this.skipped_effects) {
+				reset_branch(e);
+			}
 		} else {
 			// append/remove branches
 			for (const fn of this.#commit_callbacks) fn();
@@ -881,6 +885,26 @@ export function eager(fn) {
 	return value;
 }
 
+/**
+ * Mark all the effects inside a skipped branch CLEAN, so that
+ * they can be correctly rescheduled later
+ * @param {Effect} effect
+ */
+function reset_branch(effect) {
+	// clean branch = nothing dirty inside, no need to traverse further
+	if ((effect.f & BRANCH_EFFECT) !== 0 && (effect.f & CLEAN) !== 0) {
+		return;
+	}
+
+	set_signal_status(effect, CLEAN);
+
+	var e = effect.first;
+	while (e !== null) {
+		reset_branch(e);
+		e = e.next;
+	}
+}
+
 /**
  * Creates a 'fork', in which state changes are evaluated but not applied to the DOM.
  * This is useful for speculatively loading data (for example) when you suspect that
diff --git a/packages/svelte/tests/runtime-runes/samples/async-skipped-branch/_config.js b/packages/svelte/tests/runtime-runes/samples/async-skipped-branch/_config.js
new file mode 100644
index 0000000000..9741b1e836
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-skipped-branch/_config.js
@@ -0,0 +1,21 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	skip_no_async: true,
+	async test({ assert, target }) {
+		const [fork_btn, counter_btn] = target.querySelectorAll('button');
+
+		flushSync(() => {
+			fork_btn.click();
+		});
+
+		assert.equal(counter_btn.textContent, '0');
+
+		flushSync(() => {
+			counter_btn.click();
+		});
+
+		assert.equal(counter_btn.textContent, '1');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-skipped-branch/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-skipped-branch/main.svelte
new file mode 100644
index 0000000000..163609ac58
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-skipped-branch/main.svelte
@@ -0,0 +1,22 @@
+<script>
+	let show = $state(false);
+	let show_async = $state(false);
+	let count = $state(0);
+</script>
+
+<button onclick={() => {
+	show = true;
+	show_async = true;
+}}>show</button>
+
+{#if show}
+	hi
+{:else}
+	{#if show || !show}
+		<button onclick={() => count++}>{count}</button>
+	{/if}
+{/if}
+
+{#if show_async}
+	{await new Promise(() => {})}
+{/if}

From 2d62ffee9c2396c05f65c677c9b298a7fcfb4020 Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Thu, 29 Jan 2026 01:28:39 +0100
Subject: [PATCH 099/142] fix: throw for unset `createContext` get on the
 server (#17580)

* fix: throw for unset `createContext` get on the server

* smol tweak

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/better-groups-swim.md                     |  5 +++++
 packages/svelte/src/internal/server/context.js       | 12 +++++++++++-
 .../samples/context-not-set-throws/_config.js        |  5 +++++
 .../samples/context-not-set-throws/main.svelte       |  9 +++++++++
 packages/svelte/tests/server-side-rendering/test.ts  |  8 ++++++--
 5 files changed, 36 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/better-groups-swim.md
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/context-not-set-throws/_config.js
 create mode 100644 packages/svelte/tests/server-side-rendering/samples/context-not-set-throws/main.svelte

diff --git a/.changeset/better-groups-swim.md b/.changeset/better-groups-swim.md
new file mode 100644
index 0000000000..0287bb142f
--- /dev/null
+++ b/.changeset/better-groups-swim.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: throw for unset `createContext` get on the server
diff --git a/packages/svelte/src/internal/server/context.js b/packages/svelte/src/internal/server/context.js
index 7779da4c1d..6a7dc1f883 100644
--- a/packages/svelte/src/internal/server/context.js
+++ b/packages/svelte/src/internal/server/context.js
@@ -17,7 +17,17 @@ export function set_ssr_context(v) {
  */
 export function createContext() {
 	const key = {};
-	return [() => getContext(key), (context) => setContext(key, context)];
+
+	return [
+		() => {
+			if (!hasContext(key)) {
+				e.missing_context();
+			}
+
+			return getContext(key);
+		},
+		(context) => setContext(key, context)
+	];
 }
 
 /**
diff --git a/packages/svelte/tests/server-side-rendering/samples/context-not-set-throws/_config.js b/packages/svelte/tests/server-side-rendering/samples/context-not-set-throws/_config.js
new file mode 100644
index 0000000000..575844faf6
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/context-not-set-throws/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	error: 'missing_context'
+});
diff --git a/packages/svelte/tests/server-side-rendering/samples/context-not-set-throws/main.svelte b/packages/svelte/tests/server-side-rendering/samples/context-not-set-throws/main.svelte
new file mode 100644
index 0000000000..c52ad927c7
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/context-not-set-throws/main.svelte
@@ -0,0 +1,9 @@
+<script module>
+	import { createContext } from 'svelte';
+
+	const [get] = createContext();
+</script>
+
+<script>
+	get();
+</script>
\ No newline at end of file
diff --git a/packages/svelte/tests/server-side-rendering/test.ts b/packages/svelte/tests/server-side-rendering/test.ts
index 2bfc84c7a1..ca98fdd9aa 100644
--- a/packages/svelte/tests/server-side-rendering/test.ts
+++ b/packages/svelte/tests/server-side-rendering/test.ts
@@ -12,6 +12,7 @@ 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')[];
@@ -76,6 +77,9 @@ const { test, run } = suite_with_variants<SSRTest, 'sync' | 'async', CompileOpti
 
 		let rendered;
 		let errored = false;
+		let body: SyncRenderOutput['body'];
+		let head: SyncRenderOutput['head'];
+		let hashes: SyncRenderOutput['hashes'];
 		try {
 			const render_result = render(Component, {
 				props: config.props || {},
@@ -83,6 +87,8 @@ const { test, run } = suite_with_variants<SSRTest, 'sync' | 'async', CompileOpti
 				csp: config.csp
 			});
 			rendered = is_async ? await render_result : render_result;
+			// we need to access these inside the try-catch otherwise errors in the script tag are not caught
+			({ body, head, hashes } = rendered);
 		} catch (error) {
 			errored = true;
 			if (config.error) {
@@ -97,8 +103,6 @@ const { test, run } = suite_with_variants<SSRTest, 'sync' | 'async', CompileOpti
 			assert.fail('Expected an error to be thrown, but rendering succeeded.');
 		}
 
-		const { body, head, hashes } = rendered;
-
 		fs.writeFileSync(
 			`${test_dir}/_output/${is_async ? 'async_rendered.html' : 'rendered.html'}`,
 			body

From 9d1dd2e1999e84082acff22def7bec1ba26a6680 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Wed, 28 Jan 2026 20:53:28 -0500
Subject: [PATCH 100/142] Version Packages (#17564)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/better-groups-swim.md   |  5 -----
 .changeset/common-boats-travel.md  |  5 -----
 .changeset/fuzzy-spies-love.md     |  5 -----
 .changeset/loose-sloths-guess.md   |  5 -----
 .changeset/plain-dancers-double.md |  5 -----
 .changeset/shaggy-phones-laugh.md  |  5 -----
 .changeset/sweet-rings-watch.md    |  5 -----
 .changeset/vast-hornets-draw.md    |  5 -----
 packages/svelte/CHANGELOG.md       | 22 ++++++++++++++++++++++
 packages/svelte/package.json       |  2 +-
 packages/svelte/src/version.js     |  2 +-
 11 files changed, 24 insertions(+), 42 deletions(-)
 delete mode 100644 .changeset/better-groups-swim.md
 delete mode 100644 .changeset/common-boats-travel.md
 delete mode 100644 .changeset/fuzzy-spies-love.md
 delete mode 100644 .changeset/loose-sloths-guess.md
 delete mode 100644 .changeset/plain-dancers-double.md
 delete mode 100644 .changeset/shaggy-phones-laugh.md
 delete mode 100644 .changeset/sweet-rings-watch.md
 delete mode 100644 .changeset/vast-hornets-draw.md

diff --git a/.changeset/better-groups-swim.md b/.changeset/better-groups-swim.md
deleted file mode 100644
index 0287bb142f..0000000000
--- a/.changeset/better-groups-swim.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: throw for unset `createContext` get on the server
diff --git a/.changeset/common-boats-travel.md b/.changeset/common-boats-travel.md
deleted file mode 100644
index bd3012bbf2..0000000000
--- a/.changeset/common-boats-travel.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: reset effects inside skipped branches
diff --git a/.changeset/fuzzy-spies-love.md b/.changeset/fuzzy-spies-love.md
deleted file mode 100644
index 9129d986bc..0000000000
--- a/.changeset/fuzzy-spies-love.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: preserve old dependencies when updating reaction inside fork
diff --git a/.changeset/loose-sloths-guess.md b/.changeset/loose-sloths-guess.md
deleted file mode 100644
index 450040349d..0000000000
--- a/.changeset/loose-sloths-guess.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': minor
----
-
-feat: allow passing `ShadowRootInit` object to custom element `shadow` option
diff --git a/.changeset/plain-dancers-double.md b/.changeset/plain-dancers-double.md
deleted file mode 100644
index ab47b8e4c7..0000000000
--- a/.changeset/plain-dancers-double.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: more conservative assignment_value_stale warnings
diff --git a/.changeset/shaggy-phones-laugh.md b/.changeset/shaggy-phones-laugh.md
deleted file mode 100644
index 8cb711491b..0000000000
--- a/.changeset/shaggy-phones-laugh.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: disregard `popover` elements when determining whether an element has content
diff --git a/.changeset/sweet-rings-watch.md b/.changeset/sweet-rings-watch.md
deleted file mode 100644
index 8ce11b2672..0000000000
--- a/.changeset/sweet-rings-watch.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: fire introstart/outrostart events after delay, if specified
diff --git a/.changeset/vast-hornets-draw.md b/.changeset/vast-hornets-draw.md
deleted file mode 100644
index 256439e9da..0000000000
--- a/.changeset/vast-hornets-draw.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: increment signal versions when discarding forks
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index af503dbb20..7abc4fb302 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,27 @@
 # svelte
 
+## 5.49.0
+
+### Minor Changes
+
+- feat: allow passing `ShadowRootInit` object to custom element `shadow` option ([#17088](https://github.com/sveltejs/svelte/pull/17088))
+
+### Patch Changes
+
+- fix: throw for unset `createContext` get on the server ([#17580](https://github.com/sveltejs/svelte/pull/17580))
+
+- fix: reset effects inside skipped branches ([#17581](https://github.com/sveltejs/svelte/pull/17581))
+
+- fix: preserve old dependencies when updating reaction inside fork ([#17579](https://github.com/sveltejs/svelte/pull/17579))
+
+- fix: more conservative assignment_value_stale warnings ([#17574](https://github.com/sveltejs/svelte/pull/17574))
+
+- fix: disregard `popover` elements when determining whether an element has content ([#17367](https://github.com/sveltejs/svelte/pull/17367))
+
+- fix: fire introstart/outrostart events after delay, if specified ([#17567](https://github.com/sveltejs/svelte/pull/17567))
+
+- fix: increment signal versions when discarding forks ([#17577](https://github.com/sveltejs/svelte/pull/17577))
+
 ## 5.48.5
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index ace4c9bd08..699473ecc6 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": "5.48.5",
+  "version": "5.49.0",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 4338ba83ae..9be1ccff87 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 = '5.48.5';
+export const VERSION = '5.49.0';
 export const PUBLIC_VERSION = '5';

From 82fde88780647ac9699d9dec4108580f1865e55b Mon Sep 17 00:00:00 2001
From: Manuel <30698007+manuel3108@users.noreply.github.com>
Date: Thu, 29 Jan 2026 03:54:29 +0100
Subject: [PATCH 101/142] fix: `print()` multiline behaviour (#17319)

* way cleaner new line handling for base_elements

* fix

* more fixes

* use esrap preview

* changeset

* bump `esrap`

* update snapshot

* update more snapshots

* Update .changeset/rich-zoos-walk.md

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/rich-zoos-walk.md                  |  5 ++
 packages/svelte/package.json                  |  2 +-
 packages/svelte/src/compiler/print/index.js   | 64 ++++---------------
 .../output.svelte                             |  2 +-
 .../output.svelte                             |  2 +-
 .../output.svelte                             |  2 +-
 .../print/samples/formatting/input.svelte     |  9 ++-
 .../print/samples/formatting/output.svelte    | 34 +++++++++-
 .../print/samples/html-document/output.svelte |  4 ++
 .../samples/style-directive/output.svelte     |  5 +-
 .../samples/svelte-fragment/output.svelte     |  1 +
 .../print/samples/svelte-head/output.svelte   |  1 +
 .../_expected/client/index.svelte.js          |  2 -
 .../_expected/server/index.svelte.js          |  1 -
 .../_expected/client/index.svelte.js          |  2 -
 .../_expected/server/index.svelte.js          |  2 -
 .../_expected/client/index.svelte.js          |  1 -
 pnpm-lock.yaml                                | 10 +--
 18 files changed, 75 insertions(+), 74 deletions(-)
 create mode 100644 .changeset/rich-zoos-walk.md

diff --git a/.changeset/rich-zoos-walk.md b/.changeset/rich-zoos-walk.md
new file mode 100644
index 0000000000..fc540d7123
--- /dev/null
+++ b/.changeset/rich-zoos-walk.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: properly separate multiline html blocks from each other in `print()`
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 699473ecc6..d7dc67d528 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -176,7 +176,7 @@
     "clsx": "^2.1.1",
     "devalue": "^5.6.2",
     "esm-env": "^1.2.1",
-    "esrap": "^2.2.1",
+    "esrap": "^2.2.2",
     "is-reference": "^3.0.3",
     "locate-character": "^3.0.0",
     "magic-string": "^0.30.11",
diff --git a/packages/svelte/src/compiler/print/index.js b/packages/svelte/src/compiler/print/index.js
index 4aed743dba..094c578b83 100644
--- a/packages/svelte/src/compiler/print/index.js
+++ b/packages/svelte/src/compiler/print/index.js
@@ -115,57 +115,17 @@ function base_element(node, context) {
 	const is_doctype_node = node.name.toLowerCase() === '!doctype';
 	const is_self_closing =
 		is_void(node.name) || (node.type === 'Component' && node.fragment.nodes.length === 0);
-	let multiline_content = false;
 
 	if (is_doctype_node) child_context.write(`>`);
 	else if (is_self_closing) {
 		child_context.write(`${multiline_attributes ? '' : ' '}/>`);
 	} else {
 		child_context.write('>');
-
-		// Process the element's content in a separate context for measurement
-		const content_context = child_context.new();
-		const allow_inline_content = child_context.measure() < LINE_BREAK_THRESHOLD;
-		block(content_context, node.fragment, allow_inline_content);
-
-		// Determine if content should be formatted on multiple lines
-		multiline_content = content_context.measure() > LINE_BREAK_THRESHOLD;
-
-		if (multiline_content) {
-			child_context.newline();
-
-			// Only indent if attributes are inline and content itself isn't already multiline
-			const should_indent = !multiline_attributes && !content_context.multiline;
-			if (should_indent) {
-				child_context.indent();
-			}
-
-			child_context.append(content_context);
-
-			if (should_indent) {
-				child_context.dedent();
-			}
-
-			child_context.newline();
-		} else {
-			child_context.append(content_context);
-		}
-
+		block(child_context, node.fragment, true);
 		child_context.write(`</${node.name}>`);
 	}
 
-	const break_line_after = child_context.measure() > LINE_BREAK_THRESHOLD;
-
-	if ((multiline_content || multiline_attributes) && !context.empty()) {
-		context.newline();
-	}
-
 	context.append(child_context);
-
-	if (is_self_closing) return;
-	if (multiline_content || multiline_attributes || break_line_after) {
-		context.newline();
-	}
 }
 
 /** @type {Visitors<AST.SvelteNode>} */
@@ -412,6 +372,8 @@ const svelte_visitors = {
 				}
 			} else {
 				sequence.push(child_node);
+
+				if (child_node.type === 'RegularElement') flush();
 			}
 		}
 
@@ -420,18 +382,20 @@ const svelte_visitors = {
 		let multiline = false;
 		let width = 0;
 
-		const child_contexts = items.map((sequence) => {
-			const child_context = context.new();
+		const child_contexts = items
+			.filter((x) => x.length > 0)
+			.map((sequence) => {
+				const child_context = context.new();
 
-			for (const node of sequence) {
-				child_context.visit(node);
-				multiline ||= child_context.multiline;
-			}
+				for (const node of sequence) {
+					child_context.visit(node);
+					multiline ||= child_context.multiline;
+				}
 
-			width += child_context.measure();
+				width += child_context.measure();
 
-			return child_context;
-		});
+				return child_context;
+			});
 
 		multiline ||= width > LINE_BREAK_THRESHOLD;
 
diff --git a/packages/svelte/tests/migrate/samples/impossible-migrate-$derived-derived-var-3/output.svelte b/packages/svelte/tests/migrate/samples/impossible-migrate-$derived-derived-var-3/output.svelte
index 26012e1115..90d2e2e036 100644
--- a/packages/svelte/tests/migrate/samples/impossible-migrate-$derived-derived-var-3/output.svelte
+++ b/packages/svelte/tests/migrate/samples/impossible-migrate-$derived-derived-var-3/output.svelte
@@ -4,4 +4,4 @@
 </script>
 <Component>
 	<slot name="derived" slot="derived" />
-</Component>
+</Component>
\ No newline at end of file
diff --git a/packages/svelte/tests/migrate/samples/impossible-migrate-slot-change-name/output.svelte b/packages/svelte/tests/migrate/samples/impossible-migrate-slot-change-name/output.svelte
index 328966b63b..20e41646b3 100644
--- a/packages/svelte/tests/migrate/samples/impossible-migrate-slot-change-name/output.svelte
+++ b/packages/svelte/tests/migrate/samples/impossible-migrate-slot-change-name/output.svelte
@@ -3,4 +3,4 @@
 	let body;
 </script>
 
-<slot name="body"></slot>
+<slot name="body"></slot>
\ No newline at end of file
diff --git a/packages/svelte/tests/migrate/samples/impossible-migrate-slot-non-identifier/output.svelte b/packages/svelte/tests/migrate/samples/impossible-migrate-slot-non-identifier/output.svelte
index 1e763577df..49e9462768 100644
--- a/packages/svelte/tests/migrate/samples/impossible-migrate-slot-non-identifier/output.svelte
+++ b/packages/svelte/tests/migrate/samples/impossible-migrate-slot-non-identifier/output.svelte
@@ -1,2 +1,2 @@
 <!-- @migration-task Error while migrating Svelte code: This migration would change the name of a slot (dashed-name to dashed_name) making the component unusable -->
-<slot name="dashed-name"></slot>
+<slot name="dashed-name"></slot>
\ No newline at end of file
diff --git a/packages/svelte/tests/print/samples/formatting/input.svelte b/packages/svelte/tests/print/samples/formatting/input.svelte
index 9b1898e9c8..43c3b363cb 100644
--- a/packages/svelte/tests/print/samples/formatting/input.svelte
+++ b/packages/svelte/tests/print/samples/formatting/input.svelte
@@ -1 +1,8 @@
-<script>import { setLocale } from '$lib/paraglide/runtime';import { m } from '$lib/paraglide/messages.js';</script><h1>{m.hello_world({ name: 'SvelteKit User' })}</h1><div><button onclick={() => setLocale('en')}>en</button><button	onclick={() => setLocale('es')}>es</button></div><p>If you use VSCode, install the <a href="https://marketplace.visualstudio.com/items?itemName=inlang.vs-code-extension" target="_blank">Sherlock i18n extension</a>for a better i18n experience.</p>
+<script>import { setLocale } from '$lib/paraglide/runtime';import { m } from '$lib/paraglide/messages.js';</script>
+
+<h1>{m.hello_world({ name: 'SvelteKit User' })}</h1><div><button onclick={() => setLocale('en')}>en</button><button	onclick={() => setLocale('es')}>es</button></div><p>If you use VSCode, install the <a href="https://marketplace.visualstudio.com/items?itemName=inlang.vs-code-extension" target="_blank">Sherlock i18n extension</a>for a better i18n experience.</p>
+
+<Component><div><button>Hello, this is a test</button><button>Hello, this is a test</button></div></Component>
+<Component><button>Hello, this is a test</button><button>Hello, this is a test</button></Component>
+<button class="foo bar" aria-label="click" onclick={() => console.log("clicked")}>Click me!</button>
+<button class="foo bar" aria-label="click" onclick={() => console.log("clicked")}><span>some fancy looking</span><span>really long button text</span></button>
diff --git a/packages/svelte/tests/print/samples/formatting/output.svelte b/packages/svelte/tests/print/samples/formatting/output.svelte
index 7b40642580..ba871c66a5 100644
--- a/packages/svelte/tests/print/samples/formatting/output.svelte
+++ b/packages/svelte/tests/print/samples/formatting/output.svelte
@@ -4,18 +4,46 @@
 </script>
 
 <h1>{m.hello_world({ name: 'SvelteKit User' })}</h1>
+
 <div>
 	<button onclick={() => setLocale('en')}>en</button>
 	<button onclick={() => setLocale('es')}>es</button>
 </div>
+
 <p>
 	If you use VSCode, install the 
 
 	<a
 		href="https://marketplace.visualstudio.com/items?itemName=inlang.vs-code-extension"
 		target="_blank"
-	>
-		Sherlock i18n extension
-	</a>
+	>Sherlock i18n extension</a>
+
 	for a better i18n experience.
 </p>
+
+<Component>
+	<div>
+		<button>Hello, this is a test</button>
+		<button>Hello, this is a test</button>
+	</div>
+</Component>
+
+<Component>
+	<button>Hello, this is a test</button>
+	<button>Hello, this is a test</button>
+</Component>
+
+<button
+	class="foo bar"
+	aria-label="click"
+	onclick={() => console.log("clicked")}
+>Click me!</button>
+
+<button
+	class="foo bar"
+	aria-label="click"
+	onclick={() => console.log("clicked")}
+>
+	<span>some fancy looking</span>
+	<span>really long button text</span>
+</button>
diff --git a/packages/svelte/tests/print/samples/html-document/output.svelte b/packages/svelte/tests/print/samples/html-document/output.svelte
index 765f9ca84b..94ef78d0a3 100644
--- a/packages/svelte/tests/print/samples/html-document/output.svelte
+++ b/packages/svelte/tests/print/samples/html-document/output.svelte
@@ -1,12 +1,16 @@
 <!doctype html>
+
 <html>
 	<head>
 		<meta charset="utf-8" />
+
 		<meta
 			name="viewport"
 			content="width=device-width, initial-scale=1.0"
 		/>
+
 		<title>Svelte App</title>
 	</head>
+
 	<body><div>Hello World</div></body>
 </html>
diff --git a/packages/svelte/tests/print/samples/style-directive/output.svelte b/packages/svelte/tests/print/samples/style-directive/output.svelte
index 5aa3a6dcdb..27c12c5d47 100644
--- a/packages/svelte/tests/print/samples/style-directive/output.svelte
+++ b/packages/svelte/tests/print/samples/style-directive/output.svelte
@@ -1,8 +1,7 @@
 <div style:color="red">...</div>
+
 <div
 	style:color
 	style:width="12rem"
 	style:background-color={darkMode ? 'black' : 'white'}
->
-	...
-</div>
+>...</div>
diff --git a/packages/svelte/tests/print/samples/svelte-fragment/output.svelte b/packages/svelte/tests/print/samples/svelte-fragment/output.svelte
index eb80023626..73a4451ed8 100644
--- a/packages/svelte/tests/print/samples/svelte-fragment/output.svelte
+++ b/packages/svelte/tests/print/samples/svelte-fragment/output.svelte
@@ -4,6 +4,7 @@
 
 <Widget>
 	<h1 slot="header">Hello</h1>
+
 	<svelte:fragment slot="footer">
 		<p>All rights reserved.</p>
 		<p>Copyright (c) 2019 Svelte Industries</p>
diff --git a/packages/svelte/tests/print/samples/svelte-head/output.svelte b/packages/svelte/tests/print/samples/svelte-head/output.svelte
index 68d352260e..da4345d731 100644
--- a/packages/svelte/tests/print/samples/svelte-head/output.svelte
+++ b/packages/svelte/tests/print/samples/svelte-head/output.svelte
@@ -1,5 +1,6 @@
 <svelte:head>
 	<title>Hello world!</title>
+
 	<meta
 		name="description"
 		content="This is where the description goes for SEO"
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 7d1fe4ec67..a8b1a43495 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
@@ -10,7 +10,6 @@ export default function Async_in_derived($$anchor, $$props) {
 	var $$promises = $.run([
 		async () => yes1 = await $.async_derived(() => 1),
 		async () => yes2 = await $.async_derived(async () => foo(await 1)),
-
 		() => no1 = $.derived(async () => {
 			return await 1;
 		}),
@@ -33,7 +32,6 @@ export default function Async_in_derived($$anchor, $$props) {
 			var promises = $.run([
 				async () => yes1 = (await $.save($.async_derived(async () => (await $.save(1))())))(),
 				async () => yes2 = (await $.save($.async_derived(async () => foo((await $.save(1))()))))(),
-
 				() => no1 = $.derived(() => (async () => {
 					return await 1;
 				})()),
diff --git a/packages/svelte/tests/snapshot/samples/async-in-derived/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-in-derived/_expected/server/index.svelte.js
index 1fd184fa79..58358b3ded 100644
--- a/packages/svelte/tests/snapshot/samples/async-in-derived/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-in-derived/_expected/server/index.svelte.js
@@ -8,7 +8,6 @@ export default function Async_in_derived($$renderer, $$props) {
 		var $$promises = $$renderer.run([
 			async () => yes1 = await 1,
 			async () => yes2 = foo(await 1),
-
 			() => no1 = (async () => {
 				return await 1;
 			})(),
diff --git a/packages/svelte/tests/snapshot/samples/function-prop-no-getter/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/function-prop-no-getter/_expected/client/index.svelte.js
index 218951b836..762a23754c 100644
--- a/packages/svelte/tests/snapshot/samples/function-prop-no-getter/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/function-prop-no-getter/_expected/client/index.svelte.js
@@ -14,7 +14,6 @@ export default function Function_prop_no_getter($$anchor) {
 		onmousedown: () => $.set(count, $.get(count) + 1),
 		onmouseup,
 		onmouseenter: () => $.set(count, plusOne($.get(count)), true),
-
 		children: ($$anchor, $$slotProps) => {
 			$.next();
 
@@ -23,7 +22,6 @@ export default function Function_prop_no_getter($$anchor) {
 			$.template_effect(() => $.set_text(text, `clicks: ${$.get(count) ?? ''}`));
 			$.append($$anchor, text);
 		},
-
 		$$slots: { default: true }
 	});
 }
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/function-prop-no-getter/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/function-prop-no-getter/_expected/server/index.svelte.js
index 855ae30d21..e2936b7f6e 100644
--- a/packages/svelte/tests/snapshot/samples/function-prop-no-getter/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/function-prop-no-getter/_expected/server/index.svelte.js
@@ -13,11 +13,9 @@ export default function Function_prop_no_getter($$renderer) {
 		onmousedown: () => count += 1,
 		onmouseup,
 		onmouseenter: () => count = plusOne(count),
-
 		children: ($$renderer) => {
 			$$renderer.push(`<!---->clicks: ${$.escape(count)}`);
 		},
-
 		$$slots: { default: true }
 	});
 }
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/functional-templating/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/functional-templating/_expected/client/index.svelte.js
index d4034dc55d..792d5421e1 100644
--- a/packages/svelte/tests/snapshot/samples/functional-templating/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/functional-templating/_expected/client/index.svelte.js
@@ -6,7 +6,6 @@ var root = $.from_tree(
 	[
 		['h1', null, 'hello'],
 		' ',
-
 		[
 			'div',
 			{ class: 'potato' },
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index b616fc0577..b14dc104ba 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -96,8 +96,8 @@ importers:
         specifier: ^1.2.1
         version: 1.2.1
       esrap:
-        specifier: ^2.2.1
-        version: 2.2.1
+        specifier: ^2.2.2
+        version: 2.2.2
       is-reference:
         specifier: ^3.0.3
         version: 3.0.3
@@ -1356,8 +1356,8 @@ packages:
     resolution: {integrity: sha512-YQLXUplAwJgCydQ78IMJywZCceoqk1oH01OERdSAJc/7U2AylwjhSCLDEtqwg811idIS/9fIU5GjG73IgjKMVg==}
     engines: {node: '>=0.10'}
 
-  esrap@2.2.1:
-    resolution: {integrity: sha512-GiYWG34AN/4CUyaWAgunGt0Rxvr1PTMlGC0vvEov/uOQYWne2bpN03Um+k8jT+q3op33mKouP2zeJ6OlM+qeUg==}
+  esrap@2.2.2:
+    resolution: {integrity: sha512-zA6497ha+qKvoWIK+WM9NAh5ni17sKZKhbS5B3PoYbBvaYHZWoS33zmFybmyqpn07RLUxSmn+RCls2/XF+d0oQ==}
 
   esrecurse@4.3.0:
     resolution: {integrity: sha512-KmfKL3b6G+RXvP8N1vr3Tq1kL/oCFgn2NYXEtqP8/L3pKapUA4G8cFVaoF3SU323CD4XypR/ffioHmkti6/Tag==}
@@ -3720,7 +3720,7 @@ snapshots:
     dependencies:
       estraverse: 5.3.0
 
-  esrap@2.2.1:
+  esrap@2.2.2:
     dependencies:
       '@jridgewell/sourcemap-codec': 1.5.0
 

From ffd65e90febc29feaca48e142126a4087fcaca9f Mon Sep 17 00:00:00 2001
From: 7nik <kifiranet@gmail.com>
Date: Thu, 29 Jan 2026 04:56:05 +0200
Subject: [PATCH 102/142] chore: allow testing in production env (#16840)

* allow testing in production env

* oops
---
 .../samples/production/_config.js             |  5 ++
 .../samples/production/main.svelte            |  7 ++
 packages/svelte/tests/suite.ts                | 66 +++++++++++++++++--
 3 files changed, 74 insertions(+), 4 deletions(-)
 create mode 100644 packages/svelte/tests/runtime-runes/samples/production/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/production/main.svelte

diff --git a/packages/svelte/tests/runtime-runes/samples/production/_config.js b/packages/svelte/tests/runtime-runes/samples/production/_config.js
new file mode 100644
index 0000000000..ce36c9d95b
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/production/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	production: true
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/production/main.svelte b/packages/svelte/tests/runtime-runes/samples/production/main.svelte
new file mode 100644
index 0000000000..d9cff745d1
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/production/main.svelte
@@ -0,0 +1,7 @@
+<script>
+    import { DEV } from "esm-env";
+
+    if (DEV) {
+        throw new Error("Dev-only code must not run");
+    }
+</script>
\ No newline at end of file
diff --git a/packages/svelte/tests/suite.ts b/packages/svelte/tests/suite.ts
index bbd252b8e1..72c40f526b 100644
--- a/packages/svelte/tests/suite.ts
+++ b/packages/svelte/tests/suite.ts
@@ -1,9 +1,11 @@
 import fs from 'node:fs';
-import { it } from 'vitest';
+import { it, vi } from 'vitest';
 
 export interface BaseTest {
 	skip?: boolean;
 	solo?: boolean;
+	/** Set `DEV` to `false` */
+	production?: boolean;
 }
 
 /**
@@ -27,11 +29,31 @@ export function suite<Test extends BaseTest>(fn: (config: Test, test_dir: string
 	return {
 		test: (config: Test) => config,
 		run: async (cwd: string, samples_dir = 'samples') => {
+			const production_tests: Array<[Function, string, Function]> = [];
+
 			await for_each_dir<Test>(cwd, samples_dir, (config, dir) => {
 				let it_fn = config.skip ? it.skip : config.solo ? it.only : it;
 
-				it_fn(dir, () => fn(config, `${cwd}/${samples_dir}/${dir}`));
+				if (config.production) {
+					production_tests.push([it_fn, dir, () => fn(config, `${cwd}/${samples_dir}/${dir}`)]);
+				} else {
+					it_fn(dir, () => fn(config, `${cwd}/${samples_dir}/${dir}`));
+				}
 			});
+
+			let mocked = false;
+			for (const [it, name, test] of production_tests) {
+				it(name, () => {
+					if (!mocked) {
+						vi.doMock('esm-env', async (importEnv) => ({
+							...(await importEnv()),
+							DEV: false
+						}));
+						mocked = true;
+					}
+					return test();
+				});
+			}
 		}
 	};
 }
@@ -45,6 +67,8 @@ export function suite_with_variants<Test extends BaseTest, Variants extends stri
 	return {
 		test: (config: Test) => config,
 		run: async (cwd: string, samples_dir = 'samples') => {
+			const production_tests: Array<[Function, string, Function]> = [];
+
 			await for_each_dir<Test>(cwd, samples_dir, (config, dir) => {
 				let called_common = false;
 				let common: any = undefined;
@@ -57,15 +81,35 @@ export function suite_with_variants<Test extends BaseTest, Variants extends stri
 					const solo = config.solo;
 					let it_fn = skip ? it.skip : solo ? it.only : it;
 
-					it_fn(`${dir} (${variant})`, async () => {
+					const test = async () => {
 						if (!called_common) {
 							called_common = true;
 							common = await common_setup(config, `${cwd}/${samples_dir}/${dir}`);
 						}
 						return fn(config, `${cwd}/${samples_dir}/${dir}`, variant, common);
-					});
+					};
+
+					if (config.production) {
+						production_tests.push([it_fn, `${dir} (${variant})`, test]);
+					} else {
+						it_fn(`${dir} (${variant})`, test);
+					}
 				}
 			});
+
+			let mocked = false;
+			for (const [it, name, test] of production_tests) {
+				it(name, () => {
+					if (!mocked) {
+						vi.doMock('esm-env', async (importEnv) => ({
+							...(await importEnv()),
+							DEV: false
+						}));
+						mocked = true;
+					}
+					return test();
+				});
+			}
 		}
 	};
 }
@@ -108,3 +152,17 @@ export function assert_ok(value: any): asserts value {
 		throw new Error(`Expected truthy value, got ${value}`);
 	}
 }
+
+function run_in_production(fn: (...args: any[]) => void | Promise<void>) {
+	return async (...args: any[]) => {
+		vi.doMock('esm-env', async (importEnv) => ({
+			...(await importEnv()),
+			DEV: false
+		}));
+		try {
+			await fn(...args);
+		} finally {
+			vi.doUnmock('esm-env');
+		}
+	};
+}

From 26b09ec420bca70d4a718f61dd83393cc2af7b72 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 28 Jan 2026 23:12:48 -0500
Subject: [PATCH 103/142] chore: bump playwright (#17565)

* chore: bump playwright

* maybe this will help somehow?

* err whatever

* fix
---
 package.json                                  |  2 +-
 packages/svelte/package.json                  |  2 +-
 .../samples/head-scripts/_config.js           |  2 +-
 packages/svelte/tests/runtime-browser/test.ts |  1 +
 pnpm-lock.yaml                                | 30 +++++++++----------
 5 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/package.json b/package.json
index 24be8bd2bc..e7faf26c13 100644
--- a/package.json
+++ b/package.json
@@ -36,7 +36,7 @@
     "eslint-plugin-lube": "^0.4.3",
     "eslint-plugin-svelte": "^3.11.0",
     "jsdom": "25.0.1",
-    "playwright": "^1.46.1",
+    "playwright": "^1.58.0",
     "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 d7dc67d528..389488dcda 100644
--- a/packages/svelte/package.json
+++ b/packages/svelte/package.json
@@ -150,7 +150,7 @@
   },
   "devDependencies": {
     "@jridgewell/trace-mapping": "^0.3.25",
-    "@playwright/test": "^1.46.1",
+    "@playwright/test": "^1.58.0",
     "@rollup/plugin-commonjs": "^28.0.1",
     "@rollup/plugin-node-resolve": "^15.3.0",
     "@rollup/plugin-terser": "^0.4.4",
diff --git a/packages/svelte/tests/runtime-browser/samples/head-scripts/_config.js b/packages/svelte/tests/runtime-browser/samples/head-scripts/_config.js
index 3ff1bf7286..4f0e53925b 100644
--- a/packages/svelte/tests/runtime-browser/samples/head-scripts/_config.js
+++ b/packages/svelte/tests/runtime-browser/samples/head-scripts/_config.js
@@ -4,7 +4,7 @@ export default test({
 	mode: ['client'],
 	async test({ assert, window }) {
 		// wait the script to load (maybe there a better way)
-		await new Promise((resolve) => setTimeout(resolve, 1));
+		await new Promise((resolve) => setTimeout(resolve, 100));
 		assert.htmlEqual(
 			window.document.body.innerHTML,
 			`<main><b id="r1">1</b><b id="r2">2</b><b id="r3">3</b></main>`
diff --git a/packages/svelte/tests/runtime-browser/test.ts b/packages/svelte/tests/runtime-browser/test.ts
index 597b2909dc..525f9ba89f 100644
--- a/packages/svelte/tests/runtime-browser/test.ts
+++ b/packages/svelte/tests/runtime-browser/test.ts
@@ -197,6 +197,7 @@ async function run_test(
 		const page = await browser.newPage();
 		page.on('console', (message) => {
 			let method = message.type();
+			// @ts-ignore
 			if (method === 'warning') method = 'warn';
 			// @ts-ignore
 			console[method](message.text());
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index b14dc104ba..6d3e66825c 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -39,8 +39,8 @@ importers:
         specifier: 25.0.1
         version: 25.0.1
       playwright:
-        specifier: ^1.46.1
-        version: 1.46.1
+        specifier: ^1.58.0
+        version: 1.58.0
       prettier:
         specifier: ^3.2.4
         version: 3.2.4
@@ -115,8 +115,8 @@ importers:
         specifier: ^0.3.25
         version: 0.3.31
       '@playwright/test':
-        specifier: ^1.46.1
-        version: 1.46.1
+        specifier: ^1.58.0
+        version: 1.58.0
       '@rollup/plugin-commonjs':
         specifier: ^28.0.1
         version: 28.0.1(rollup@4.52.5)
@@ -667,8 +667,8 @@ packages:
     resolution: {integrity: sha512-+1VkjdD0QBLPodGrJUeqarH8VAIvQODIbwh9XpP5Syisf7YoQgsJKPNFoqqLQlu+VQ/tVSshMR6loPMn8U+dPg==}
     engines: {node: '>=14'}
 
-  '@playwright/test@1.46.1':
-    resolution: {integrity: sha512-Fq6SwLujA/DOIvNC2EL/SojJnkKf/rAwJ//APpJJHRyMi1PdKrY3Az+4XNQ51N4RTbItbIByQ0jgd1tayq1aeA==}
+  '@playwright/test@1.58.0':
+    resolution: {integrity: sha512-fWza+Lpbj6SkQKCrU6si4iu+fD2dD3gxNHFhUPxsfXBPhnv3rRSQVd0NtBUT9Z/RhF/boCBcuUaMUSTRTopjZg==}
     engines: {node: '>=18'}
     hasBin: true
 
@@ -1937,13 +1937,13 @@ packages:
     resolution: {integrity: sha512-uB80kBFb/tfd68bVleG9T5GGsGPjJrLAUpR5PZIrhBnIaRTQRjqdJSsIKkOP6OAIFbj7GOrcudc5pNjZ+geV2g==}
     engines: {node: '>=6'}
 
-  playwright-core@1.46.1:
-    resolution: {integrity: sha512-h9LqIQaAv+CYvWzsZ+h3RsrqCStkBHlgo6/TJlFst3cOTlLghBQlJwPOZKQJTKNaD3QIB7aAVQ+gfWbN3NXB7A==}
+  playwright-core@1.58.0:
+    resolution: {integrity: sha512-aaoB1RWrdNi3//rOeKuMiS65UCcgOVljU46At6eFcOFPFHWtd2weHRRow6z/n+Lec0Lvu0k9ZPKJSjPugikirw==}
     engines: {node: '>=18'}
     hasBin: true
 
-  playwright@1.46.1:
-    resolution: {integrity: sha512-oPcr1yqoXLCkgKtD5eNUPLiN40rYEM39odNpIb6VE6S7/15gJmA1NzVv6zJYusV0e7tzvkU/utBFNa/Kpxmwng==}
+  playwright@1.58.0:
+    resolution: {integrity: sha512-2SVA0sbPktiIY/MCOPX8e86ehA/e+tDNq+e5Y8qjKYti2Z/JG7xnronT/TXTIkKbYGWlCbuucZ6dziEgkoEjQQ==}
     engines: {node: '>=18'}
     hasBin: true
 
@@ -2973,9 +2973,9 @@ snapshots:
   '@pkgjs/parseargs@0.11.0':
     optional: true
 
-  '@playwright/test@1.46.1':
+  '@playwright/test@1.58.0':
     dependencies:
-      playwright: 1.46.1
+      playwright: 1.58.0
 
   '@polka/url@1.0.0-next.25': {}
 
@@ -4253,11 +4253,11 @@ snapshots:
 
   pify@4.0.1: {}
 
-  playwright-core@1.46.1: {}
+  playwright-core@1.58.0: {}
 
-  playwright@1.46.1:
+  playwright@1.58.0:
     dependencies:
-      playwright-core: 1.46.1
+      playwright-core: 1.58.0
     optionalDependencies:
       fsevents: 2.3.2
 

From 704d0cd765d1c7d92601888e95898fcd99ce550c Mon Sep 17 00:00:00 2001
From: 7nik <kifiranet@gmail.com>
Date: Thu, 29 Jan 2026 23:00:39 +0200
Subject: [PATCH 104/142] chore: allow testing in production env 2 (#17590)

* Revert "chore: allow testing in production env (#16840)"

This reverts commit ffd65e90febc29feaca48e142126a4087fcaca9f.

* new approach
---
 .../samples/production-internals/Child.svelte |  5 ++
 .../samples/production-internals/_config.js   | 12 ++++
 .../samples/production-internals/main.svelte  | 19 ++++++
 .../samples/production/main.svelte            |  0
 .../svelte/tests/runtime-production/test.ts   | 17 +++++
 .../samples/production/_config.js             |  5 --
 packages/svelte/tests/suite.ts                | 66 ++-----------------
 7 files changed, 57 insertions(+), 67 deletions(-)
 create mode 100644 packages/svelte/tests/runtime-production/samples/production-internals/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-production/samples/production-internals/_config.js
 create mode 100644 packages/svelte/tests/runtime-production/samples/production-internals/main.svelte
 rename packages/svelte/tests/{runtime-runes => runtime-production}/samples/production/main.svelte (100%)
 create mode 100644 packages/svelte/tests/runtime-production/test.ts
 delete mode 100644 packages/svelte/tests/runtime-runes/samples/production/_config.js

diff --git a/packages/svelte/tests/runtime-production/samples/production-internals/Child.svelte b/packages/svelte/tests/runtime-production/samples/production-internals/Child.svelte
new file mode 100644
index 0000000000..36b548ab8b
--- /dev/null
+++ b/packages/svelte/tests/runtime-production/samples/production-internals/Child.svelte
@@ -0,0 +1,5 @@
+<script>
+	let { foo = $bindable(42) } = $props();
+</script>
+
+{foo};
diff --git a/packages/svelte/tests/runtime-production/samples/production-internals/_config.js b/packages/svelte/tests/runtime-production/samples/production-internals/_config.js
new file mode 100644
index 0000000000..6ac08f7012
--- /dev/null
+++ b/packages/svelte/tests/runtime-production/samples/production-internals/_config.js
@@ -0,0 +1,12 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ target }) {
+		let button = target.querySelector('button');
+
+		button?.click();
+
+		flushSync();
+	}
+});
diff --git a/packages/svelte/tests/runtime-production/samples/production-internals/main.svelte b/packages/svelte/tests/runtime-production/samples/production-internals/main.svelte
new file mode 100644
index 0000000000..0629644a01
--- /dev/null
+++ b/packages/svelte/tests/runtime-production/samples/production-internals/main.svelte
@@ -0,0 +1,19 @@
+<script>
+	import Child from "./Child.svelte";
+
+	let foo;
+
+	function onerror(err) {
+		// re-throw if it isn't the production error
+		// do in a such way because config.error is checked via `includes`
+		if (err.message !== 'https://svelte.dev/e/props_invalid_value') {
+			throw err;
+		}
+	}
+</script>
+
+<svelte:boundary {onerror}>
+	<Child bind:foo />
+</svelte:boundary>
+
+
diff --git a/packages/svelte/tests/runtime-runes/samples/production/main.svelte b/packages/svelte/tests/runtime-production/samples/production/main.svelte
similarity index 100%
rename from packages/svelte/tests/runtime-runes/samples/production/main.svelte
rename to packages/svelte/tests/runtime-production/samples/production/main.svelte
diff --git a/packages/svelte/tests/runtime-production/test.ts b/packages/svelte/tests/runtime-production/test.ts
new file mode 100644
index 0000000000..1c9a00ab83
--- /dev/null
+++ b/packages/svelte/tests/runtime-production/test.ts
@@ -0,0 +1,17 @@
+// @vitest-environment jsdom
+
+import { vi } from 'vitest';
+import { runtime_suite, ok } from '../runtime-legacy/shared';
+
+vi.mock('esm-env', async (importEnv) => {
+	return {
+		...(await importEnv()),
+		DEV: false
+	};
+});
+
+const { test, run } = runtime_suite(true);
+
+export { test, ok };
+
+await run(__dirname);
diff --git a/packages/svelte/tests/runtime-runes/samples/production/_config.js b/packages/svelte/tests/runtime-runes/samples/production/_config.js
deleted file mode 100644
index ce36c9d95b..0000000000
--- a/packages/svelte/tests/runtime-runes/samples/production/_config.js
+++ /dev/null
@@ -1,5 +0,0 @@
-import { test } from '../../test';
-
-export default test({
-	production: true
-});
diff --git a/packages/svelte/tests/suite.ts b/packages/svelte/tests/suite.ts
index 72c40f526b..bbd252b8e1 100644
--- a/packages/svelte/tests/suite.ts
+++ b/packages/svelte/tests/suite.ts
@@ -1,11 +1,9 @@
 import fs from 'node:fs';
-import { it, vi } from 'vitest';
+import { it } from 'vitest';
 
 export interface BaseTest {
 	skip?: boolean;
 	solo?: boolean;
-	/** Set `DEV` to `false` */
-	production?: boolean;
 }
 
 /**
@@ -29,31 +27,11 @@ export function suite<Test extends BaseTest>(fn: (config: Test, test_dir: string
 	return {
 		test: (config: Test) => config,
 		run: async (cwd: string, samples_dir = 'samples') => {
-			const production_tests: Array<[Function, string, Function]> = [];
-
 			await for_each_dir<Test>(cwd, samples_dir, (config, dir) => {
 				let it_fn = config.skip ? it.skip : config.solo ? it.only : it;
 
-				if (config.production) {
-					production_tests.push([it_fn, dir, () => fn(config, `${cwd}/${samples_dir}/${dir}`)]);
-				} else {
-					it_fn(dir, () => fn(config, `${cwd}/${samples_dir}/${dir}`));
-				}
+				it_fn(dir, () => fn(config, `${cwd}/${samples_dir}/${dir}`));
 			});
-
-			let mocked = false;
-			for (const [it, name, test] of production_tests) {
-				it(name, () => {
-					if (!mocked) {
-						vi.doMock('esm-env', async (importEnv) => ({
-							...(await importEnv()),
-							DEV: false
-						}));
-						mocked = true;
-					}
-					return test();
-				});
-			}
 		}
 	};
 }
@@ -67,8 +45,6 @@ export function suite_with_variants<Test extends BaseTest, Variants extends stri
 	return {
 		test: (config: Test) => config,
 		run: async (cwd: string, samples_dir = 'samples') => {
-			const production_tests: Array<[Function, string, Function]> = [];
-
 			await for_each_dir<Test>(cwd, samples_dir, (config, dir) => {
 				let called_common = false;
 				let common: any = undefined;
@@ -81,35 +57,15 @@ export function suite_with_variants<Test extends BaseTest, Variants extends stri
 					const solo = config.solo;
 					let it_fn = skip ? it.skip : solo ? it.only : it;
 
-					const test = async () => {
+					it_fn(`${dir} (${variant})`, async () => {
 						if (!called_common) {
 							called_common = true;
 							common = await common_setup(config, `${cwd}/${samples_dir}/${dir}`);
 						}
 						return fn(config, `${cwd}/${samples_dir}/${dir}`, variant, common);
-					};
-
-					if (config.production) {
-						production_tests.push([it_fn, `${dir} (${variant})`, test]);
-					} else {
-						it_fn(`${dir} (${variant})`, test);
-					}
+					});
 				}
 			});
-
-			let mocked = false;
-			for (const [it, name, test] of production_tests) {
-				it(name, () => {
-					if (!mocked) {
-						vi.doMock('esm-env', async (importEnv) => ({
-							...(await importEnv()),
-							DEV: false
-						}));
-						mocked = true;
-					}
-					return test();
-				});
-			}
 		}
 	};
 }
@@ -152,17 +108,3 @@ export function assert_ok(value: any): asserts value {
 		throw new Error(`Expected truthy value, got ${value}`);
 	}
 }
-
-function run_in_production(fn: (...args: any[]) => void | Promise<void>) {
-	return async (...args: any[]) => {
-		vi.doMock('esm-env', async (importEnv) => ({
-			...(await importEnv()),
-			DEV: false
-		}));
-		try {
-			await fn(...args);
-		} finally {
-			vi.doUnmock('esm-env');
-		}
-	};
-}

From 5656dd569a36b02e8871d7461631975601e879d1 Mon Sep 17 00:00:00 2001
From: Antonio Bennett <31296212+Antonio-Bennett@users.noreply.github.com>
Date: Thu, 29 Jan 2026 19:23:34 -0500
Subject: [PATCH 105/142] fix: handle renderer.run rejections (#17591)

* fix: handle renderer run rejections

* add test

* changeset

* simplify

* explanatory comment

---------

Co-authored-by: Antonio Bennett <abennett@mabelslabels.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/tidy-zebras-design.md                           | 5 +++++
 packages/svelte/src/internal/server/renderer.js            | 6 ++++++
 .../runtime-runes/samples/async-error-in-script/_config.js | 6 ++++++
 .../samples/async-error-in-script/main.svelte              | 7 +++++++
 4 files changed, 24 insertions(+)
 create mode 100644 .changeset/tidy-zebras-design.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-error-in-script/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-error-in-script/main.svelte

diff --git a/.changeset/tidy-zebras-design.md b/.changeset/tidy-zebras-design.md
new file mode 100644
index 0000000000..3b18af798f
--- /dev/null
+++ b/.changeset/tidy-zebras-design.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: prevent unhandled exceptions arising from dangling promises in <script>
diff --git a/packages/svelte/src/internal/server/renderer.js b/packages/svelte/src/internal/server/renderer.js
index 4da0b05cfd..65f9bcae6a 100644
--- a/packages/svelte/src/internal/server/renderer.js
+++ b/packages/svelte/src/internal/server/renderer.js
@@ -11,6 +11,7 @@ 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 { noop } from '../shared/utils.js';
 
 /** @typedef {'head' | 'body'} RendererType */
 /** @typedef {{ [key in RendererType]: string }} AccumulatedContent */
@@ -162,6 +163,11 @@ export class Renderer {
 			promises.push(promise);
 		}
 
+		// 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;
+
 		return promises;
 	}
 
diff --git a/packages/svelte/tests/runtime-runes/samples/async-error-in-script/_config.js b/packages/svelte/tests/runtime-runes/samples/async-error-in-script/_config.js
new file mode 100644
index 0000000000..2e0fab473c
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-error-in-script/_config.js
@@ -0,0 +1,6 @@
+import { test } from '../../test';
+
+export default test({
+	mode: ['async-server', 'hydrate'],
+	error: 'oops'
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-error-in-script/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-error-in-script/main.svelte
new file mode 100644
index 0000000000..64d9e6ce08
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-error-in-script/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	await 1;
+
+	throw new Error('oops');
+</script>
+
+<h1>hello</h1>

From ebe583f2bb1d341b9e0474374124796d0f035e5c Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Thu, 29 Jan 2026 19:28:36 -0500
Subject: [PATCH 106/142] fix: only create async functions in SSR output when
 necessary (#17593)

* fix: only create async functions in SSR output when necessary

* actually...

* simplify generated code a bit more

* simplify
---
 .changeset/hot-insects-stare.md               |  5 +++++
 .../server/visitors/RegularElement.js         | 20 +++++++++----------
 .../server/visitors/SvelteElement.js          |  2 +-
 .../server/visitors/shared/utils.js           |  5 ++---
 4 files changed, 18 insertions(+), 14 deletions(-)
 create mode 100644 .changeset/hot-insects-stare.md

diff --git a/.changeset/hot-insects-stare.md b/.changeset/hot-insects-stare.md
new file mode 100644
index 0000000000..fb4109c35e
--- /dev/null
+++ b/.changeset/hot-insects-stare.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: only create async functions in SSR output when necessary
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 79858b95d9..5b905752f4 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
@@ -70,8 +70,7 @@ export function RegularElement(node, context) {
 		if (optimiser.expressions.length > 0) {
 			context.state.template.push(
 				create_child_block(
-					b.block([optimiser.apply(), ...state.init, ...build_template(state.template)]),
-					true
+					b.block([optimiser.apply(), ...state.init, ...build_template(state.template)])
 				)
 			);
 		} else {
@@ -133,7 +132,7 @@ export function RegularElement(node, context) {
 
 		if (optimiser.expressions.length > 0) {
 			context.state.template.push(
-				create_child_block(b.block([optimiser.apply(), ...state.init, statement]), true)
+				create_child_block(b.block([optimiser.apply(), ...state.init, statement]))
 			);
 		} else {
 			context.state.template.push(...state.init, statement);
@@ -186,7 +185,7 @@ export function RegularElement(node, context) {
 
 		if (optimiser.expressions.length > 0) {
 			context.state.template.push(
-				create_child_block(b.block([optimiser.apply(), ...state.init, statement]), true)
+				create_child_block(b.block([optimiser.apply(), ...state.init, statement]))
 			);
 		} else {
 			context.state.template.push(...state.init, statement);
@@ -236,18 +235,19 @@ export function RegularElement(node, context) {
 	}
 
 	if (optimiser.is_async()) {
-		let statement = create_child_block(
-			b.block([optimiser.apply(), ...state.init, ...build_template(state.template)]),
-			true
-		);
+		let statements = [...state.init, ...build_template(state.template)];
+
+		if (optimiser.has_await) {
+			statements = [create_child_block(b.block([optimiser.apply(), ...statements]))];
+		}
 
 		const blockers = optimiser.blockers();
 
 		if (blockers.elements.length > 0) {
-			statement = create_async_block(b.block([statement]), blockers, false, false);
+			statements = [create_async_block(b.block(statements), blockers, false, false)];
 		}
 
-		context.state.template.push(statement);
+		context.state.template.push(...statements);
 	} else {
 		context.state.init.push(...state.init);
 		context.state.template.push(...state.template);
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js
index 1ac15893f2..75ba323e20 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js
@@ -79,7 +79,7 @@ export function SvelteElement(node, context) {
 	);
 
 	if (optimiser.expressions.length > 0) {
-		statement = create_child_block(b.block([optimiser.apply(), statement]), true);
+		statement = create_child_block(b.block([optimiser.apply(), statement]));
 	}
 
 	statements.push(statement);
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 4736a7c5da..b02a935ed2 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
@@ -264,11 +264,10 @@ export function build_getter(node, state) {
 /**
  * Creates a `$$renderer.child(...)` expression statement
  * @param {BlockStatement | Expression} body
- * @param {boolean} async
  * @returns {Statement}
  */
-export function create_child_block(body, async) {
-	return b.stmt(b.call('$$renderer.child', b.arrow([b.id('$$renderer')], body, async)));
+export function create_child_block(body) {
+	return b.stmt(b.call('$$renderer.child', b.arrow([b.id('$$renderer')], body, true)));
 }
 
 /**

From 8933653fbea644699ca2a2d316f017ad3cdfb269 Mon Sep 17 00:00:00 2001
From: FORMI <239411042+Richman018@users.noreply.github.com>
Date: Fri, 30 Jan 2026 09:40:40 +0800
Subject: [PATCH 107/142] fix: merge consecutive text nodes during hydration
 for large text content (#17587)

* fix: merge consecutive text nodes during hydration for large text content

Fixes #17582

Browsers automatically split text nodes exceeding 65536 characters into
multiple consecutive text nodes during HTML parsing. This causes hydration
mismatches when Svelte expects a single text node.

The fix merges consecutive text nodes during hydration by:
- Detecting when the current node is a text node
- Finding all consecutive text node siblings
- Merging their content into the first text node
- Removing the extra text nodes

This restores correct hydration behavior for large text content.

* add test, fix

* fix

* fix

* changeset

---------

Co-authored-by: Miner <miner@example.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/deep-bears-see.md                  |  5 ++
 .../src/internal/client/dom/operations.js     | 73 ++++++++++++++-----
 .../src/internal/client/dom/template.js       |  6 +-
 .../hydrate-large-text-node/_config.js        | 24 ++++++
 .../hydrate-large-text-node/main.svelte       |  5 ++
 packages/svelte/tests/runtime-browser/test.ts |  2 +-
 6 files changed, 93 insertions(+), 22 deletions(-)
 create mode 100644 .changeset/deep-bears-see.md
 create mode 100644 packages/svelte/tests/runtime-browser/samples/hydrate-large-text-node/_config.js
 create mode 100644 packages/svelte/tests/runtime-browser/samples/hydrate-large-text-node/main.svelte

diff --git a/.changeset/deep-bears-see.md b/.changeset/deep-bears-see.md
new file mode 100644
index 0000000000..9f59b31d12
--- /dev/null
+++ b/.changeset/deep-bears-see.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: merge consecutive large text nodes
diff --git a/packages/svelte/src/internal/client/dom/operations.js b/packages/svelte/src/internal/client/dom/operations.js
index 479c2ba0a5..61a48bcbfb 100644
--- a/packages/svelte/src/internal/client/dom/operations.js
+++ b/packages/svelte/src/internal/client/dom/operations.js
@@ -122,6 +122,10 @@ export function child(node, is_text) {
 		return text;
 	}
 
+	if (is_text) {
+		merge_text_nodes(/** @type {Text} */ (child));
+	}
+
 	set_hydrate_node(child);
 	return child;
 }
@@ -142,14 +146,18 @@ export function first_child(node, is_text = false) {
 		return first;
 	}
 
-	// if an {expression} is empty during SSR, there might be no
-	// text node to hydrate — we must therefore create one
-	if (is_text && hydrate_node?.nodeType !== TEXT_NODE) {
-		var text = create_text();
+	if (is_text) {
+		// if an {expression} is empty during SSR, there might be no
+		// text node to hydrate — we must therefore create one
+		if (hydrate_node?.nodeType !== TEXT_NODE) {
+			var text = create_text();
 
-		hydrate_node?.before(text);
-		set_hydrate_node(text);
-		return text;
+			hydrate_node?.before(text);
+			set_hydrate_node(text);
+			return text;
+		}
+
+		merge_text_nodes(/** @type {Text} */ (hydrate_node));
 	}
 
 	return hydrate_node;
@@ -175,20 +183,24 @@ export function sibling(node, count = 1, is_text = false) {
 		return next_sibling;
 	}
 
-	// if a sibling {expression} is empty during SSR, there might be no
-	// text node to hydrate — we must therefore create one
-	if (is_text && next_sibling?.nodeType !== TEXT_NODE) {
-		var text = create_text();
-		// If the next sibling is `null` and we're handling text then it's because
-		// the SSR content was empty for the text, so we need to generate a new text
-		// node and insert it after the last sibling
-		if (next_sibling === null) {
-			last_sibling?.after(text);
-		} else {
-			next_sibling.before(text);
+	if (is_text) {
+		// if a sibling {expression} is empty during SSR, there might be no
+		// text node to hydrate — we must therefore create one
+		if (next_sibling?.nodeType !== TEXT_NODE) {
+			var text = create_text();
+			// If the next sibling is `null` and we're handling text then it's because
+			// the SSR content was empty for the text, so we need to generate a new text
+			// node and insert it after the last sibling
+			if (next_sibling === null) {
+				last_sibling?.after(text);
+			} else {
+				next_sibling.before(text);
+			}
+			set_hydrate_node(text);
+			return text;
 		}
-		set_hydrate_node(text);
-		return text;
+
+		merge_text_nodes(/** @type {Text} */ (next_sibling));
 	}
 
 	set_hydrate_node(next_sibling);
@@ -258,3 +270,24 @@ export function set_attribute(element, key, value = '') {
 	}
 	return element.setAttribute(key, value);
 }
+
+/**
+ * Browsers split text nodes larger than 65536 bytes when parsing.
+ * For hydration to succeed, we need to stitch them back together
+ * @param {Text} text
+ */
+export function merge_text_nodes(text) {
+	if (/** @type {string} */ (text.nodeValue).length < 65536) {
+		return;
+	}
+
+	let next = text.nextSibling;
+
+	while (next !== null && next.nodeType === TEXT_NODE) {
+		next.remove();
+
+		/** @type {string} */ (text.nodeValue) += /** @type {string} */ (next.nodeValue);
+
+		next = text.nextSibling;
+	}
+}
diff --git a/packages/svelte/src/internal/client/dom/template.js b/packages/svelte/src/internal/client/dom/template.js
index 0d827218bc..567fbeabf0 100644
--- a/packages/svelte/src/internal/client/dom/template.js
+++ b/packages/svelte/src/internal/client/dom/template.js
@@ -4,11 +4,13 @@ import { hydrate_next, hydrate_node, hydrating, set_hydrate_node } from './hydra
 import {
 	create_text,
 	get_first_child,
+	get_next_sibling,
 	is_firefox,
 	create_element,
 	create_fragment,
 	create_comment,
-	set_attribute
+	set_attribute,
+	merge_text_nodes
 } from './operations.js';
 import { create_fragment_from_html } from './reconciler.js';
 import { active_effect } from '../runtime.js';
@@ -310,6 +312,8 @@ export function text(value = '') {
 		// if an {expression} is empty during SSR, we need to insert an empty text node
 		node.before((node = create_text()));
 		set_hydrate_node(node);
+	} else {
+		merge_text_nodes(/** @type {Text} */ (node));
 	}
 
 	assign_nodes(node, node);
diff --git a/packages/svelte/tests/runtime-browser/samples/hydrate-large-text-node/_config.js b/packages/svelte/tests/runtime-browser/samples/hydrate-large-text-node/_config.js
new file mode 100644
index 0000000000..3a52b1ccd3
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/samples/hydrate-large-text-node/_config.js
@@ -0,0 +1,24 @@
+import { test } from '../../assert';
+
+// Browsers split text nodes > 65536 characters into multiple consecutive text nodes
+// during HTML parsing. This test verifies that hydration correctly merges them.
+const LARGE_TEXT = 'x'.repeat(70000);
+
+export default test({
+	mode: ['hydrate'],
+	skip_mode: ['client'],
+
+	props: {
+		text: LARGE_TEXT
+	},
+
+	async test({ assert, target }) {
+		const [p] = target.querySelectorAll('p');
+
+		// The text content should be preserved after hydration
+		assert.equal(p.textContent?.trim(), LARGE_TEXT);
+		// After hydration, there should be only one text node (plus possible comment nodes)
+		const textNodes = [...p.childNodes].filter((node) => node.nodeType === 3);
+		assert.equal(textNodes.length, 1, `Expected 1 text node, got ${textNodes.length}`);
+	}
+});
diff --git a/packages/svelte/tests/runtime-browser/samples/hydrate-large-text-node/main.svelte b/packages/svelte/tests/runtime-browser/samples/hydrate-large-text-node/main.svelte
new file mode 100644
index 0000000000..d65358dabc
--- /dev/null
+++ b/packages/svelte/tests/runtime-browser/samples/hydrate-large-text-node/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	let { text } = $props();
+</script>
+
+<p>{text}</p>
diff --git a/packages/svelte/tests/runtime-browser/test.ts b/packages/svelte/tests/runtime-browser/test.ts
index 525f9ba89f..54cdc0f8be 100644
--- a/packages/svelte/tests/runtime-browser/test.ts
+++ b/packages/svelte/tests/runtime-browser/test.ts
@@ -213,7 +213,7 @@ async function run_test(
 		}
 
 		// uncomment to see what was generated
-		// fs.writeFileSync(`${test_dir}/_actual.js`, build_result.outputFiles[0].text);
+		// fs.writeFileSync(`${test_dir}/_output/bundle-${hydrate}.js`, build_result.outputFiles[0].text);
 		const test_result = await page.evaluate(
 			build_result.outputFiles[0].text + ";test.default(document.querySelector('main'))"
 		);

From 92e6721c035d336458ebbe6cb23236ac8e7fd50c Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Thu, 29 Jan 2026 22:32:41 -0500
Subject: [PATCH 108/142] Version Packages (#17585)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/deep-bears-see.md     |  5 -----
 .changeset/hot-insects-stare.md  |  5 -----
 .changeset/rich-zoos-walk.md     |  5 -----
 .changeset/tidy-zebras-design.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/deep-bears-see.md
 delete mode 100644 .changeset/hot-insects-stare.md
 delete mode 100644 .changeset/rich-zoos-walk.md
 delete mode 100644 .changeset/tidy-zebras-design.md

diff --git a/.changeset/deep-bears-see.md b/.changeset/deep-bears-see.md
deleted file mode 100644
index 9f59b31d12..0000000000
--- a/.changeset/deep-bears-see.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: merge consecutive large text nodes
diff --git a/.changeset/hot-insects-stare.md b/.changeset/hot-insects-stare.md
deleted file mode 100644
index fb4109c35e..0000000000
--- a/.changeset/hot-insects-stare.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: only create async functions in SSR output when necessary
diff --git a/.changeset/rich-zoos-walk.md b/.changeset/rich-zoos-walk.md
deleted file mode 100644
index fc540d7123..0000000000
--- a/.changeset/rich-zoos-walk.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: properly separate multiline html blocks from each other in `print()`
diff --git a/.changeset/tidy-zebras-design.md b/.changeset/tidy-zebras-design.md
deleted file mode 100644
index 3b18af798f..0000000000
--- a/.changeset/tidy-zebras-design.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: prevent unhandled exceptions arising from dangling promises in <script>
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 7abc4fb302..c7c38302e8 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,17 @@
 # svelte
 
+## 5.49.1
+
+### Patch Changes
+
+- fix: merge consecutive large text nodes ([#17587](https://github.com/sveltejs/svelte/pull/17587))
+
+- fix: only create async functions in SSR output when necessary ([#17593](https://github.com/sveltejs/svelte/pull/17593))
+
+- fix: properly separate multiline html blocks from each other in `print()` ([#17319](https://github.com/sveltejs/svelte/pull/17319))
+
+- fix: prevent unhandled exceptions arising from dangling promises in <script> ([#17591](https://github.com/sveltejs/svelte/pull/17591))
+
 ## 5.49.0
 
 ### Minor Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 389488dcda..fd4b98679e 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": "5.49.0",
+  "version": "5.49.1",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 9be1ccff87..557b1ff156 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 = '5.49.0';
+export const VERSION = '5.49.1';
 export const PUBLIC_VERSION = '5';

From cd8d40af1ae755ca7c889f3aa1b6c3d8d0c14dd7 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Mon, 2 Feb 2026 22:40:14 +0100
Subject: [PATCH 109/142] chore: robustify playground decode (#17606)

For some reason LLMs like to percent-encode stuff, this makes the download script still run in that case
---
 playgrounds/sandbox/scripts/download.js | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/playgrounds/sandbox/scripts/download.js b/playgrounds/sandbox/scripts/download.js
index e3c862cb61..538b4956fe 100644
--- a/playgrounds/sandbox/scripts/download.js
+++ b/playgrounds/sandbox/scripts/download.js
@@ -635,7 +635,19 @@ if (is_local) {
 } else if (url && url.origin === 'https://svelte.dev' && url.pathname.startsWith('/playground/')) {
 	// Svelte playground URL handling (existing logic)
 	if (url.hash.length > 1) {
-		const decoded = atob(url.hash.slice(1).replaceAll('-', '+').replaceAll('_', '/'));
+		// Decode percent-encoded characters (e.g., %5F => _), and replace base64 chars.
+		let decoded;
+		try {
+			// First, decode URI components to handle %xx encodings (e.g. %5F -> _) (LLMs calling this script sometimes encode them for some reason)
+			decoded = url.hash.slice(1);
+			decoded = decodeURIComponent(decoded);
+
+			// Now, restore for base64 (replace -/+, _/ /)
+			decoded = atob(decoded.replaceAll('-', '+').replaceAll('_', '/'));
+		} catch (e) {
+			console.error('Failed to decode URL hash:', e);
+			process.exit(1);
+		}
 		// putting it directly into the blob gives a corrupted file
 		const u8 = new Uint8Array(decoded.length);
 		for (let i = 0; i < decoded.length; i++) {

From bc4dc1d10d54ecbc61398a248f8a45a4f4bcfa13 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Wed, 4 Feb 2026 10:28:32 +0100
Subject: [PATCH 110/142] fix: avoid erroneous async derived expressions for
 blocks (#17604)

fixes #17595

When an if/key/etc block has an expression that depends on an async blocker (e.g., is inside a component with top level `await`), the compiler incorrectly treats the expression as async - even when the expression itself contains no `await`.

This causes the expression to be added to `$.async`'s `expressions` array, which wraps it in an `async_derived`. This is not only unnecessary but also buggy: it breaks the direct reactive connection between the source and its dependent effects, causing inconsistent effect executions.

The fix is to only add expressions to `$.async`'s `expressions` array when they actually contain an `await`.

When a branch is speculatively marked for destruction (condition temporarily falsy), its child effects are reset to `CLEAN` to prevent them running in a doomed branch (as of #17581). However, if the branch survives (condition becomes truthy again), those effects remain `CLEAN` and never run - the source was already marked dirty before the reset, so no new dirty marking occurs.

The fix is to change `skipped_effects` from a `Set` to a `Map` that tracks which child effects were dirty/maybe_dirty before being reset. When a branch is unskipped (survives), restore their status and reschedule them.

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/some-teams-pay.md                  |  5 ++
 .changeset/yummy-insects-wonder.md            |  5 ++
 .../3-transform/client/visitors/EachBlock.js  | 15 +++--
 .../3-transform/client/visitors/HtmlTag.js    | 14 ++--
 .../3-transform/client/visitors/IfBlock.js    | 14 ++--
 .../3-transform/client/visitors/KeyBlock.js   | 32 +++++----
 .../client/visitors/SvelteElement.js          | 14 ++--
 .../internal/client/dom/blocks/branches.js    |  8 +--
 .../src/internal/client/dom/blocks/each.js    |  4 +-
 .../src/internal/client/reactivity/batch.js   | 65 +++++++++++++++----
 .../svelte/tests/runtime-legacy/shared.ts     |  4 +-
 .../Child.svelte                              |  9 +++
 .../_config.js                                | 16 +++++
 .../main.svelte                               | 14 ++++
 14 files changed, 166 insertions(+), 53 deletions(-)
 create mode 100644 .changeset/some-teams-pay.md
 create mode 100644 .changeset/yummy-insects-wonder.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-derived-unmount-undefined-props/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-derived-unmount-undefined-props/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-derived-unmount-undefined-props/main.svelte

diff --git a/.changeset/some-teams-pay.md b/.changeset/some-teams-pay.md
new file mode 100644
index 0000000000..d7ae69566d
--- /dev/null
+++ b/.changeset/some-teams-pay.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: avoid erroneous async derived expressions for blocks
diff --git a/.changeset/yummy-insects-wonder.md b/.changeset/yummy-insects-wonder.md
new file mode 100644
index 0000000000..6e705cd8cf
--- /dev/null
+++ b/.changeset/yummy-insects-wonder.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: reschedule effects inside unskipped branches
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 c0bfe272e5..1dbc34fdc3 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
@@ -312,10 +312,10 @@ export function EachBlock(node, context) {
 		declarations.push(b.let(node.index, index));
 	}
 
-	const is_async = node.metadata.expression.is_async();
+	const has_await = node.metadata.expression.has_await;
 
-	const get_collection = b.thunk(collection, node.metadata.expression.has_await);
-	const thunk = is_async ? b.thunk(b.call('$.get', b.id('$$collection'))) : get_collection;
+	const get_collection = b.thunk(collection, has_await);
+	const thunk = has_await ? b.thunk(b.call('$.get', b.id('$$collection'))) : get_collection;
 
 	const render_args = [b.id('$$anchor'), item];
 	if (uses_index || collection_id) render_args.push(index);
@@ -342,15 +342,18 @@ export function EachBlock(node, context) {
 		statements.unshift(b.stmt(b.call('$.validate_each_keys', thunk, key_function)));
 	}
 
-	if (is_async) {
+	if (node.metadata.expression.is_async()) {
 		context.state.init.push(
 			b.stmt(
 				b.call(
 					'$.async',
 					context.state.node,
 					node.metadata.expression.blockers(),
-					b.array([get_collection]),
-					b.arrow([context.state.node, b.id('$$collection')], b.block(statements))
+					has_await ? b.array([get_collection]) : b.void0,
+					b.arrow(
+						has_await ? [context.state.node, b.id('$$collection')] : [context.state.node],
+						b.block(statements)
+					)
 				)
 			)
 		);
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 0567edc610..2706cf7f0a 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
@@ -11,10 +11,11 @@ import { build_expression } from './shared/utils.js';
 export function HtmlTag(node, context) {
 	context.state.template.push_comment();
 
-	const is_async = node.metadata.expression.is_async();
+	const has_await = node.metadata.expression.has_await;
+	const has_blockers = node.metadata.expression.has_blockers();
 
 	const expression = build_expression(context, node.expression, node.metadata.expression);
-	const html = is_async ? b.call('$.get', b.id('$$html')) : expression;
+	const html = has_await ? b.call('$.get', b.id('$$html')) : expression;
 
 	const is_svg = context.state.metadata.namespace === 'svg';
 	const is_mathml = context.state.metadata.namespace === 'mathml';
@@ -31,15 +32,18 @@ export function HtmlTag(node, context) {
 	);
 
 	// push into init, so that bindings run afterwards, which might trigger another run and override hydration
-	if (is_async) {
+	if (has_await || has_blockers) {
 		context.state.init.push(
 			b.stmt(
 				b.call(
 					'$.async',
 					context.state.node,
 					node.metadata.expression.blockers(),
-					b.array([b.thunk(expression, node.metadata.expression.has_await)]),
-					b.arrow([context.state.node, b.id('$$html')], b.block([statement]))
+					has_await ? b.array([b.thunk(expression, true)]) : b.void0,
+					b.arrow(
+						has_await ? [context.state.node, b.id('$$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 fcbb59ba74..c0e66635df 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
@@ -25,10 +25,11 @@ export function IfBlock(node, context) {
 		statements.push(b.var(alternate_id, b.arrow([b.id('$$anchor')], alternate)));
 	}
 
-	const is_async = node.metadata.expression.is_async();
+	const has_await = node.metadata.expression.has_await;
+	const has_blockers = node.metadata.expression.has_blockers();
 
 	const expression = build_expression(context, node.test, node.metadata.expression);
-	const test = is_async ? b.call('$.get', b.id('$$condition')) : expression;
+	const test = has_await ? b.call('$.get', b.id('$$condition')) : expression;
 
 	/** @type {Expression[]} */
 	const args = [
@@ -72,15 +73,18 @@ export function IfBlock(node, context) {
 
 	statements.push(add_svelte_meta(b.call('$.if', ...args), node, 'if'));
 
-	if (is_async) {
+	if (has_await || has_blockers) {
 		context.state.init.push(
 			b.stmt(
 				b.call(
 					'$.async',
 					context.state.node,
 					node.metadata.expression.blockers(),
-					b.array([b.thunk(expression, node.metadata.expression.has_await)]),
-					b.arrow([context.state.node, b.id('$$condition')], b.block(statements))
+					has_await ? b.array([b.thunk(expression, true)]) : b.void0,
+					b.arrow(
+						has_await ? [context.state.node, b.id('$$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 d050155e8b..143a4e8edd 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
@@ -11,29 +11,35 @@ import { build_expression, add_svelte_meta } from './shared/utils.js';
 export function KeyBlock(node, context) {
 	context.state.template.push_comment();
 
-	const is_async = node.metadata.expression.is_async();
+	const has_await = node.metadata.expression.has_await;
+	const has_blockers = node.metadata.expression.has_blockers();
 
 	const expression = build_expression(context, node.expression, node.metadata.expression);
-	const key = b.thunk(is_async ? b.call('$.get', b.id('$$key')) : expression);
+	const key = b.thunk(has_await ? b.call('$.get', b.id('$$key')) : expression);
 	const body = /** @type {Expression} */ (context.visit(node.fragment));
 
-	let statement = add_svelte_meta(
+	const statement = add_svelte_meta(
 		b.call('$.key', context.state.node, key, b.arrow([b.id('$$anchor')], body)),
 		node,
 		'key'
 	);
 
-	if (is_async) {
-		statement = b.stmt(
-			b.call(
-				'$.async',
-				context.state.node,
-				node.metadata.expression.blockers(),
-				b.array([b.thunk(expression, node.metadata.expression.has_await)]),
-				b.arrow([context.state.node, b.id('$$key')], b.block([statement]))
+	if (has_await || has_blockers) {
+		context.state.init.push(
+			b.stmt(
+				b.call(
+					'$.async',
+					context.state.node,
+					node.metadata.expression.blockers(),
+					has_await ? b.array([b.thunk(expression, true)]) : b.void0,
+					b.arrow(
+						has_await ? [context.state.node, b.id('$$key')] : [context.state.node],
+						b.block([statement])
+					)
+				)
 			)
 		);
+	} else {
+		context.state.init.push(statement);
 	}
-
-	context.state.init.push(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 c8192cf00a..10024298fa 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
@@ -93,10 +93,11 @@ export function SvelteElement(node, context) {
 		);
 	}
 
-	const is_async = node.metadata.expression.is_async();
+	const has_await = node.metadata.expression.has_await;
+	const has_blockers = node.metadata.expression.has_blockers();
 
 	const expression = /** @type {Expression} */ (context.visit(node.tag));
-	const get_tag = b.thunk(is_async ? b.call('$.get', b.id('$$tag')) : expression);
+	const get_tag = b.thunk(has_await ? b.call('$.get', b.id('$$tag')) : expression);
 
 	/** @type {Statement[]} */
 	const inner = inner_context.state.init;
@@ -139,15 +140,18 @@ export function SvelteElement(node, context) {
 		)
 	);
 
-	if (is_async) {
+	if (has_await || has_blockers) {
 		context.state.init.push(
 			b.stmt(
 				b.call(
 					'$.async',
 					context.state.node,
 					node.metadata.expression.blockers(),
-					b.array([b.thunk(expression, node.metadata.expression.has_await)]),
-					b.arrow([context.state.node, b.id('$$tag')], b.block(statements))
+					has_await ? b.array([b.thunk(expression, true)]) : b.void0,
+					b.arrow(
+						has_await ? [context.state.node, b.id('$$tag')] : [context.state.node],
+						b.block(statements)
+					)
 				)
 			)
 		);
diff --git a/packages/svelte/src/internal/client/dom/blocks/branches.js b/packages/svelte/src/internal/client/dom/blocks/branches.js
index 527f0b0a8f..6b77903574 100644
--- a/packages/svelte/src/internal/client/dom/blocks/branches.js
+++ b/packages/svelte/src/internal/client/dom/blocks/branches.js
@@ -200,17 +200,17 @@ export class BranchManager {
 		if (defer) {
 			for (const [k, effect] of this.#onscreen) {
 				if (k === key) {
-					batch.skipped_effects.delete(effect);
+					batch.unskip_effect(effect);
 				} else {
-					batch.skipped_effects.add(effect);
+					batch.skip_effect(effect);
 				}
 			}
 
 			for (const [k, branch] of this.#offscreen) {
 				if (k === key) {
-					batch.skipped_effects.delete(branch.effect);
+					batch.unskip_effect(branch.effect);
 				} else {
-					batch.skipped_effects.add(branch.effect);
+					batch.skip_effect(branch.effect);
 				}
 			}
 
diff --git a/packages/svelte/src/internal/client/dom/blocks/each.js b/packages/svelte/src/internal/client/dom/blocks/each.js
index 232656ec11..6eaeac0f38 100644
--- a/packages/svelte/src/internal/client/dom/blocks/each.js
+++ b/packages/svelte/src/internal/client/dom/blocks/each.js
@@ -257,7 +257,7 @@ export function each(node, flags, get_collection, get_key, render_fn, fallback_f
 				if (item.i) internal_set(item.i, index);
 
 				if (defer) {
-					batch.skipped_effects.delete(item.e);
+					batch.unskip_effect(item.e);
 				}
 			} else {
 				item = create_item(
@@ -299,7 +299,7 @@ export function each(node, flags, get_collection, get_key, render_fn, fallback_f
 			if (defer) {
 				for (const [key, item] of items) {
 					if (!keys.has(key)) {
-						batch.skipped_effects.add(item.e);
+						batch.skip_effect(item.e);
 					}
 				}
 
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index 2b6e84889b..cef2df4716 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -130,11 +130,13 @@ export class Batch {
 	#maybe_dirty_effects = new Set();
 
 	/**
-	 * A set of branches that still exist, but will be destroyed when this batch
-	 * is committed — we skip over these during `process`
-	 * @type {Set<Effect>}
+	 * A map of branches that still exist, but will be destroyed when this batch
+	 * is committed — we skip over these during `process`.
+	 * The value contains child effects that were dirty/maybe_dirty before being reset,
+	 * so they can be rescheduled if the branch survives.
+	 * @type {Map<Effect, { d: Effect[], m: Effect[] }>}
 	 */
-	skipped_effects = new Set();
+	#skipped_branches = new Map();
 
 	is_fork = false;
 
@@ -144,6 +146,38 @@ export class Batch {
 		return this.is_fork || this.#blocking_pending > 0;
 	}
 
+	/**
+	 * Add an effect to the #skipped_branches map and reset its children
+	 * @param {Effect} effect
+	 */
+	skip_effect(effect) {
+		if (!this.#skipped_branches.has(effect)) {
+			this.#skipped_branches.set(effect, { d: [], m: [] });
+		}
+	}
+
+	/**
+	 * Remove an effect from the #skipped_branches map and reschedule
+	 * any tracked dirty/maybe_dirty child effects
+	 * @param {Effect} effect
+	 */
+	unskip_effect(effect) {
+		var tracked = this.#skipped_branches.get(effect);
+		if (tracked) {
+			this.#skipped_branches.delete(effect);
+
+			for (var e of tracked.d) {
+				set_signal_status(e, DIRTY);
+				schedule_effect(e);
+			}
+
+			for (e of tracked.m) {
+				set_signal_status(e, MAYBE_DIRTY);
+				schedule_effect(e);
+			}
+		}
+	}
+
 	/**
 	 *
 	 * @param {Effect[]} root_effects
@@ -172,8 +206,8 @@ export class Batch {
 			this.#defer_effects(render_effects);
 			this.#defer_effects(effects);
 
-			for (const e of this.skipped_effects) {
-				reset_branch(e);
+			for (const [e, t] of this.#skipped_branches) {
+				reset_branch(e, t);
 			}
 		} else {
 			// append/remove branches
@@ -220,7 +254,7 @@ export class Batch {
 			var is_branch = (flags & (BRANCH_EFFECT | ROOT_EFFECT)) !== 0;
 			var is_skippable_branch = is_branch && (flags & CLEAN) !== 0;
 
-			var skip = is_skippable_branch || (flags & INERT) !== 0 || this.skipped_effects.has(effect);
+			var skip = is_skippable_branch || (flags & INERT) !== 0 || this.#skipped_branches.has(effect);
 
 			// Inside a `<svelte:boundary>` with a pending snippet,
 			// all effects are deferred until the boundary resolves
@@ -807,7 +841,8 @@ export function schedule_effect(signal) {
 		var flags = effect.f;
 
 		// if the effect is being scheduled because a parent (each/await/etc) block
-		// updated an internal source, bail out or we'll cause a second flush
+		// updated an internal source, or because a branch is being unskipped,
+		// bail out or we'll cause a second flush
 		if (
 			is_flushing &&
 			effect === active_effect &&
@@ -887,20 +922,28 @@ export function eager(fn) {
 
 /**
  * Mark all the effects inside a skipped branch CLEAN, so that
- * they can be correctly rescheduled later
+ * they can be correctly rescheduled later. Tracks dirty and maybe_dirty
+ * effects so they can be rescheduled if the branch survives.
  * @param {Effect} effect
+ * @param {{ d: Effect[], m: Effect[] }} tracked
  */
-function reset_branch(effect) {
+function reset_branch(effect, tracked) {
 	// clean branch = nothing dirty inside, no need to traverse further
 	if ((effect.f & BRANCH_EFFECT) !== 0 && (effect.f & CLEAN) !== 0) {
 		return;
 	}
 
+	if ((effect.f & DIRTY) !== 0) {
+		tracked.d.push(effect);
+	} else if ((effect.f & MAYBE_DIRTY) !== 0) {
+		tracked.m.push(effect);
+	}
+
 	set_signal_status(effect, CLEAN);
 
 	var e = effect.first;
 	while (e !== null) {
-		reset_branch(e);
+		reset_branch(e, tracked);
 		e = e.next;
 	}
 }
diff --git a/packages/svelte/tests/runtime-legacy/shared.ts b/packages/svelte/tests/runtime-legacy/shared.ts
index 13975c68ee..8c29a6ada2 100644
--- a/packages/svelte/tests/runtime-legacy/shared.ts
+++ b/packages/svelte/tests/runtime-legacy/shared.ts
@@ -47,9 +47,9 @@ export interface RuntimeTest<Props extends Record<string, any> = Record<string,
 	mode?: Array<'server' | 'async-server' | 'client' | 'hydrate'>;
 	/** Temporarily skip specific modes, without skipping the entire test */
 	skip_mode?: Array<'server' | 'async-server' | 'client' | 'hydrate'>;
-	/** Skip if running with process.env.NO_ASYNC */
+	/** Skip if running with process.env.SVELTE_NO_ASYNC */
 	skip_no_async?: boolean;
-	/** Skip if running without process.env.NO_ASYNC */
+	/** Skip if running without process.env.SVELTE_NO_ASYNC */
 	skip_async?: boolean;
 	html?: string;
 	ssrHtml?: string;
diff --git a/packages/svelte/tests/runtime-runes/samples/async-derived-unmount-undefined-props/Child.svelte b/packages/svelte/tests/runtime-runes/samples/async-derived-unmount-undefined-props/Child.svelte
new file mode 100644
index 0000000000..fecbe222e3
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-derived-unmount-undefined-props/Child.svelte
@@ -0,0 +1,9 @@
+<script>
+	let { id } = $props();
+
+	// BUG: This logs 'undefined' on unmount when parent has async derived
+	const data = $derived(await Promise.resolve(id).then((x) => {
+		console.log('promise resolved with:', x);
+		return x;
+	}));
+</script>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-derived-unmount-undefined-props/_config.js b/packages/svelte/tests/runtime-runes/samples/async-derived-unmount-undefined-props/_config.js
new file mode 100644
index 0000000000..2f371bc6b7
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-derived-unmount-undefined-props/_config.js
@@ -0,0 +1,16 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target, logs }) {
+		await tick();
+
+		assert.deepEqual(logs, ['promise resolved with:', 'some-id']);
+
+		const button = target.querySelector('button');
+		button?.click();
+		await tick();
+
+		assert.deepEqual(logs, ['promise resolved with:', 'some-id']);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-derived-unmount-undefined-props/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-derived-unmount-undefined-props/main.svelte
new file mode 100644
index 0000000000..d5cdd5967e
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-derived-unmount-undefined-props/main.svelte
@@ -0,0 +1,14 @@
+<script>
+	import Child from './Child.svelte';
+
+	// This async derived in parent triggers the bug
+	const something = $derived(await Promise.resolve('test'));
+
+	let active = $state('some-id');
+</script>
+
+{#if active}
+	<Child id={active} />
+{/if}
+
+<button onclick={() => active = undefined}>close</button>

From baba15ab981a3b090eaabefe3425f5f4ea9a8074 Mon Sep 17 00:00:00 2001
From: Tee Ming <chewteeming01@gmail.com>
Date: Thu, 5 Feb 2026 00:31:33 +0800
Subject: [PATCH 111/142] fix: avoid 'node:crypto' cloudflare warnings (#17612)

* fix: avoid 'node:crypto' cloudflare warnings

* format

* changeset

* Apply suggestion from @teemingc
---
 .changeset/violet-pans-know.md                | 5 +++++
 packages/svelte/src/internal/server/crypto.js | 3 ++-
 2 files changed, 7 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/violet-pans-know.md

diff --git a/.changeset/violet-pans-know.md b/.changeset/violet-pans-know.md
new file mode 100644
index 0000000000..59bf1dcaaf
--- /dev/null
+++ b/.changeset/violet-pans-know.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: avoid Cloudflare warnings about not having the "node:crypto" module
diff --git a/packages/svelte/src/internal/server/crypto.js b/packages/svelte/src/internal/server/crypto.js
index 8727635481..9bb6ecdd39 100644
--- a/packages/svelte/src/internal/server/crypto.js
+++ b/packages/svelte/src/internal/server/crypto.js
@@ -12,7 +12,8 @@ export async function sha256(data) {
 	crypto ??= globalThis.crypto?.subtle?.digest
 		? globalThis.crypto
 		: // @ts-ignore - we don't install node types in the prod build
-			(await import('node:crypto')).webcrypto;
+			// don't use 'node:crypto' because static analysers will think we rely on node when we don't
+			(await import('node:' + 'crypto')).webcrypto;
 
 	const hash_buffer = await crypto.subtle.digest('SHA-256', text_encoder.encode(data));
 

From 05229d96823cc88d11c0b4a81b357cdb67f69326 Mon Sep 17 00:00:00 2001
From: Tee Ming <chewteeming01@gmail.com>
Date: Thu, 5 Feb 2026 00:32:33 +0800
Subject: [PATCH 112/142] chore: remove SvelteKit data attributes from
 elements.d.ts (#17613)

* Remove SvelteKit data attributes from elements.d.ts

Removed SvelteKit specific data attributes from elements.d.ts.

* Remove SvelteKit data attributes from elements.d.ts

Removed SvelteKit data attributes from elements.d.ts.

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/quiet-buttons-bathe.md |  5 +++++
 packages/svelte/elements.d.ts     | 17 -----------------
 2 files changed, 5 insertions(+), 17 deletions(-)
 create mode 100644 .changeset/quiet-buttons-bathe.md

diff --git a/.changeset/quiet-buttons-bathe.md b/.changeset/quiet-buttons-bathe.md
new file mode 100644
index 0000000000..419a5569b4
--- /dev/null
+++ b/.changeset/quiet-buttons-bathe.md
@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+chore: remove SvelteKit data attributes from elements.d.ts
diff --git a/packages/svelte/elements.d.ts b/packages/svelte/elements.d.ts
index fa74124472..885004dd2a 100644
--- a/packages/svelte/elements.d.ts
+++ b/packages/svelte/elements.d.ts
@@ -851,23 +851,6 @@ export interface HTMLAttributes<T extends EventTarget> extends AriaAttributes, D
 	readonly 'bind:offsetWidth'?: number | undefined | null;
 	readonly 'bind:offsetHeight'?: number | undefined | null;
 
-	// SvelteKit
-	'data-sveltekit-keepfocus'?: true | '' | 'off' | undefined | null;
-	'data-sveltekit-noscroll'?: true | '' | 'off' | undefined | null;
-	'data-sveltekit-preload-code'?:
-		| true
-		| ''
-		| 'eager'
-		| 'viewport'
-		| 'hover'
-		| 'tap'
-		| 'off'
-		| undefined
-		| null;
-	'data-sveltekit-preload-data'?: true | '' | 'hover' | 'tap' | 'off' | undefined | null;
-	'data-sveltekit-reload'?: true | '' | 'off' | undefined | null;
-	'data-sveltekit-replacestate'?: true | '' | 'off' | undefined | null;
-
 	// allow any data- attribute
 	[key: `data-${string}`]: any;
 

From eb63a6bbbaffec07890ae181b02edf4c52e2586a Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Wed, 4 Feb 2026 11:52:30 -0500
Subject: [PATCH 113/142] Version Packages (#17614)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/quiet-buttons-bathe.md  |  5 -----
 .changeset/some-teams-pay.md       |  5 -----
 .changeset/violet-pans-know.md     |  5 -----
 .changeset/yummy-insects-wonder.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/quiet-buttons-bathe.md
 delete mode 100644 .changeset/some-teams-pay.md
 delete mode 100644 .changeset/violet-pans-know.md
 delete mode 100644 .changeset/yummy-insects-wonder.md

diff --git a/.changeset/quiet-buttons-bathe.md b/.changeset/quiet-buttons-bathe.md
deleted file mode 100644
index 419a5569b4..0000000000
--- a/.changeset/quiet-buttons-bathe.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-"svelte": patch
----
-
-chore: remove SvelteKit data attributes from elements.d.ts
diff --git a/.changeset/some-teams-pay.md b/.changeset/some-teams-pay.md
deleted file mode 100644
index d7ae69566d..0000000000
--- a/.changeset/some-teams-pay.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: avoid erroneous async derived expressions for blocks
diff --git a/.changeset/violet-pans-know.md b/.changeset/violet-pans-know.md
deleted file mode 100644
index 59bf1dcaaf..0000000000
--- a/.changeset/violet-pans-know.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: avoid Cloudflare warnings about not having the "node:crypto" module
diff --git a/.changeset/yummy-insects-wonder.md b/.changeset/yummy-insects-wonder.md
deleted file mode 100644
index 6e705cd8cf..0000000000
--- a/.changeset/yummy-insects-wonder.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: reschedule effects inside unskipped branches
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index c7c38302e8..a71effd5dd 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,17 @@
 # svelte
 
+## 5.49.2
+
+### Patch Changes
+
+- chore: remove SvelteKit data attributes from elements.d.ts ([#17613](https://github.com/sveltejs/svelte/pull/17613))
+
+- fix: avoid erroneous async derived expressions for blocks ([#17604](https://github.com/sveltejs/svelte/pull/17604))
+
+- fix: avoid Cloudflare warnings about not having the "node:crypto" module ([#17612](https://github.com/sveltejs/svelte/pull/17612))
+
+- fix: reschedule effects inside unskipped branches ([#17604](https://github.com/sveltejs/svelte/pull/17604))
+
 ## 5.49.1
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index fd4b98679e..48f492783f 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": "5.49.1",
+  "version": "5.49.2",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 557b1ff156..31538c3fe7 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 = '5.49.1';
+export const VERSION = '5.49.2';
 export const PUBLIC_VERSION = '5';

From 4f41e816baa007fb6a4e31164da49576e87e342e Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 4 Feb 2026 13:07:46 -0500
Subject: [PATCH 114/142] fix: ensure infinite effect loops are cleared after
 flushing (#17601)

* failing effect-loop-infinite test

* fix
---
 .changeset/chatty-mammals-find.md                     |  5 +++++
 .../svelte/src/internal/client/reactivity/batch.js    |  3 ++-
 packages/svelte/tests/runtime-legacy/shared.ts        |  2 ++
 .../samples/effect-loop-infinite/_config.js           | 11 ++++++-----
 4 files changed, 15 insertions(+), 6 deletions(-)
 create mode 100644 .changeset/chatty-mammals-find.md

diff --git a/.changeset/chatty-mammals-find.md b/.changeset/chatty-mammals-find.md
new file mode 100644
index 0000000000..373dc0059a
--- /dev/null
+++ b/.changeset/chatty-mammals-find.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: ensure infinite effect loops are cleared after flushing
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index cef2df4716..9bf93c873f 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -647,8 +647,9 @@ function flush_effects() {
 			}
 		}
 	} finally {
-		is_flushing = false;
+		queued_root_effects = [];
 
+		is_flushing = false;
 		last_scheduled_effect = null;
 
 		if (DEV) {
diff --git a/packages/svelte/tests/runtime-legacy/shared.ts b/packages/svelte/tests/runtime-legacy/shared.ts
index 8c29a6ada2..c5317f822e 100644
--- a/packages/svelte/tests/runtime-legacy/shared.ts
+++ b/packages/svelte/tests/runtime-legacy/shared.ts
@@ -521,6 +521,8 @@ async function run_test_variant(
 						errors,
 						hydrate: hydrate_fn
 					});
+
+					flushSync();
 				}
 
 				if (config.runtime_error && !unhandled_rejection) {
diff --git a/packages/svelte/tests/runtime-runes/samples/effect-loop-infinite/_config.js b/packages/svelte/tests/runtime-runes/samples/effect-loop-infinite/_config.js
index 57f60c2b44..44cf5b09e2 100644
--- a/packages/svelte/tests/runtime-runes/samples/effect-loop-infinite/_config.js
+++ b/packages/svelte/tests/runtime-runes/samples/effect-loop-infinite/_config.js
@@ -11,11 +11,12 @@ export default test({
 	test({ assert, errors }) {
 		const [button] = document.querySelectorAll('button');
 
-		try {
+		assert.throws(() => {
 			flushSync(() => button.click());
-		} catch (e) {
-			assert.equal(errors.length, 1); // for whatever reason we can't get the name which should be 'updated at'
-			assert.ok(/** @type {Error} */ (e).message.startsWith('effect_update_depth_exceeded'));
-		}
+		}, /effect_update_depth_exceeded/);
+
+		assert.equal(errors.length, 1);
+
+		assert.doesNotThrow(flushSync);
 	}
 });

From d7a8e3d1300fbb802b84a6ebf0f3f71ed734a556 Mon Sep 17 00:00:00 2001
From: 7nik <kifiranet@gmail.com>
Date: Wed, 4 Feb 2026 21:51:50 +0200
Subject: [PATCH 115/142] fix: emit `each_key_duplicate` error in production
 (#16724)

* fix: emit `each_key_duplicate` error in production

* fix: preserve key

* Update packages/svelte/src/internal/client/dom/blocks/each.js

Co-authored-by: Rich Harris <rich.harris@vercel.com>

* Update packages/svelte/src/internal/client/dom/blocks/each.js

Co-authored-by: Rich Harris <rich.harris@vercel.com>

* fix: ensure keys are validated

* fix silly test name

* fix: cover other case of duplicate keys

* emit error on hydration

* ensure the error is handled

* drop useless tests

* unused

* finish merge

* add lost check back

* chore: bump playwright (#17565)

* chore: bump playwright

* maybe this will help somehow?

* err whatever

* fix

* chore: allow testing in production env 2 (#17590)

* Revert "chore: allow testing in production env (#16840)"

This reverts commit ffd65e90febc29feaca48e142126a4087fcaca9f.

* new approach

* fix: handle renderer.run rejections (#17591)

* fix: handle renderer run rejections

* add test

* changeset

* simplify

* explanatory comment

---------

Co-authored-by: Antonio Bennett <abennett@mabelslabels.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>

* fix: only create async functions in SSR output when necessary (#17593)

* fix: only create async functions in SSR output when necessary

* actually...

* simplify generated code a bit more

* simplify

* fix: merge consecutive text nodes during hydration for large text content (#17587)

* fix: merge consecutive text nodes during hydration for large text content

Fixes #17582

Browsers automatically split text nodes exceeding 65536 characters into
multiple consecutive text nodes during HTML parsing. This causes hydration
mismatches when Svelte expects a single text node.

The fix merges consecutive text nodes during hydration by:
- Detecting when the current node is a text node
- Finding all consecutive text node siblings
- Merging their content into the first text node
- Removing the extra text nodes

This restores correct hydration behavior for large text content.

* add test, fix

* fix

* fix

* changeset

---------

Co-authored-by: Miner <miner@example.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>

* Version Packages (#17585)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

* Revert "drop useless tests"

This reverts commit 65f77ef8409d6e8c91163f36853d36b05ec01ae8.

* update tests

* fix test

* we don't need to expose this function any more

* figured it out... we cant have errors during reconcile

* simplify

* tweak

* unused

* revert no-longer-needed change

* unused

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
Co-authored-by: Antonio Bennett <31296212+Antonio-Bennett@users.noreply.github.com>
Co-authored-by: Antonio Bennett <abennett@mabelslabels.com>
Co-authored-by: FORMI <239411042+Richman018@users.noreply.github.com>
Co-authored-by: Miner <miner@example.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/sharp-snakes-poke.md               |  5 +++
 .../3-transform/client/visitors/EachBlock.js  |  4 --
 .../src/internal/client/dom/blocks/each.js    | 37 +++++++++++++++++++
 packages/svelte/src/internal/client/index.js  |  2 +-
 .../svelte/src/internal/client/validate.js    | 34 -----------------
 .../samples/keyed-each-unique-2/_config.js    | 12 ++++++
 .../samples/keyed-each-unique-2/main.svelte   |  8 ++++
 .../samples/keyed-each-unique-3/_config.js    |  5 +++
 .../samples/keyed-each-unique-3/main.svelte   |  7 ++++
 .../samples/keyed-each-unique/_config.js      | 12 ++++++
 .../samples/keyed-each-unique/main.svelte     |  8 ++++
 11 files changed, 95 insertions(+), 39 deletions(-)
 create mode 100644 .changeset/sharp-snakes-poke.md
 create mode 100644 packages/svelte/tests/runtime-production/samples/keyed-each-unique-2/_config.js
 create mode 100644 packages/svelte/tests/runtime-production/samples/keyed-each-unique-2/main.svelte
 create mode 100644 packages/svelte/tests/runtime-production/samples/keyed-each-unique-3/_config.js
 create mode 100644 packages/svelte/tests/runtime-production/samples/keyed-each-unique-3/main.svelte
 create mode 100644 packages/svelte/tests/runtime-production/samples/keyed-each-unique/_config.js
 create mode 100644 packages/svelte/tests/runtime-production/samples/keyed-each-unique/main.svelte

diff --git a/.changeset/sharp-snakes-poke.md b/.changeset/sharp-snakes-poke.md
new file mode 100644
index 0000000000..7f7f8aa7b2
--- /dev/null
+++ b/.changeset/sharp-snakes-poke.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: emit `each_key_duplicate` error in production
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 1dbc34fdc3..b2724fa90f 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
@@ -338,10 +338,6 @@ export function EachBlock(node, context) {
 
 	const statements = [add_svelte_meta(b.call('$.each', ...args), node, 'each')];
 
-	if (dev && node.metadata.keyed) {
-		statements.unshift(b.stmt(b.call('$.validate_each_keys', thunk, key_function)));
-	}
-
 	if (node.metadata.expression.is_async()) {
 		context.state.init.push(
 			b.stmt(
diff --git a/packages/svelte/src/internal/client/dom/blocks/each.js b/packages/svelte/src/internal/client/dom/blocks/each.js
index 6eaeac0f38..25f7cf91eb 100644
--- a/packages/svelte/src/internal/client/dom/blocks/each.js
+++ b/packages/svelte/src/internal/client/dom/blocks/each.js
@@ -40,6 +40,7 @@ import { get } from '../../runtime.js';
 import { DEV } from 'esm-env';
 import { derived_safe_equal } from '../../reactivity/deriveds.js';
 import { current_batch } from '../../reactivity/batch.js';
+import * as e from '../../errors.js';
 
 // When making substantive changes to this file, validate them with the each block stress test:
 // https://svelte.dev/playground/1972b2cf46564476ad8c8c6405b23b7b
@@ -290,6 +291,15 @@ export function each(node, flags, get_collection, get_key, render_fn, fallback_f
 			}
 		}
 
+		if (length > keys.size) {
+			if (DEV) {
+				validate_each_keys(array, get_key);
+			} else {
+				// in prod, the additional information isn't printed, so don't bother computing it
+				e.each_key_duplicate('', '', '');
+			}
+		}
+
 		// remove excess nodes
 		if (hydrating && length > 0) {
 			set_hydrate_node(skip_nodes());
@@ -676,3 +686,30 @@ function link(state, prev, next) {
 		next.prev = prev;
 	}
 }
+
+/**
+ * @param {Array<any>} array
+ * @param {(item: any, index: number) => string} key_fn
+ * @returns {void}
+ */
+function validate_each_keys(array, key_fn) {
+	const keys = new Map();
+	const length = array.length;
+
+	for (let i = 0; i < length; i++) {
+		const key = key_fn(array[i], i);
+
+		if (keys.has(key)) {
+			const a = String(keys.get(key));
+			const b = String(i);
+
+			/** @type {string | null} */
+			let k = String(key);
+			if (k.startsWith('[object ')) k = null;
+
+			e.each_key_duplicate(a, b, k);
+		}
+
+		keys.set(key, i);
+	}
+}
diff --git a/packages/svelte/src/internal/client/index.js b/packages/svelte/src/internal/client/index.js
index 1d9f7dfff7..7fcaf77dc5 100644
--- a/packages/svelte/src/internal/client/index.js
+++ b/packages/svelte/src/internal/client/index.js
@@ -158,7 +158,7 @@ export {
 	deep_read_state,
 	active_effect
 } from './runtime.js';
-export { validate_binding, validate_each_keys } from './validate.js';
+export { validate_binding } from './validate.js';
 export { raf } from './timing.js';
 export { proxy } from './proxy.js';
 export { create_custom_element } from './dom/elements/custom-element.js';
diff --git a/packages/svelte/src/internal/client/validate.js b/packages/svelte/src/internal/client/validate.js
index 48a44db304..a169225f1e 100644
--- a/packages/svelte/src/internal/client/validate.js
+++ b/packages/svelte/src/internal/client/validate.js
@@ -1,45 +1,11 @@
 /** @import { Blocker } from '#client' */
 import { dev_current_component_function } from './context.js';
-import { is_array } from '../shared/utils.js';
-import * as e from './errors.js';
 import { FILENAME } from '../../constants.js';
 import { render_effect } from './reactivity/effects.js';
 import * as w from './warnings.js';
 import { capture_store_binding } from './reactivity/store.js';
 import { run_after_blockers } from './reactivity/async.js';
 
-/**
- * @param {() => any} collection
- * @param {(item: any, index: number) => string} key_fn
- * @returns {void}
- */
-export function validate_each_keys(collection, key_fn) {
-	render_effect(() => {
-		const keys = new Map();
-		const maybe_array = collection();
-		const array = is_array(maybe_array)
-			? maybe_array
-			: maybe_array == null
-				? []
-				: Array.from(maybe_array);
-		const length = array.length;
-		for (let i = 0; i < length; i++) {
-			const key = key_fn(array[i], i);
-			if (keys.has(key)) {
-				const a = String(keys.get(key));
-				const b = String(i);
-
-				/** @type {string | null} */
-				let k = String(key);
-				if (k.startsWith('[object ')) k = null;
-
-				e.each_key_duplicate(a, b, k);
-			}
-			keys.set(key, i);
-		}
-	});
-}
-
 /**
  * @param {string} binding
  * @param {Blocker[]} blockers
diff --git a/packages/svelte/tests/runtime-production/samples/keyed-each-unique-2/_config.js b/packages/svelte/tests/runtime-production/samples/keyed-each-unique-2/_config.js
new file mode 100644
index 0000000000..bc945876ea
--- /dev/null
+++ b/packages/svelte/tests/runtime-production/samples/keyed-each-unique-2/_config.js
@@ -0,0 +1,12 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	test({ assert, target }) {
+		let button = target.querySelector('button');
+
+		button?.click();
+
+		assert.throws(flushSync, 'https://svelte.dev/e/each_key_duplicate');
+	}
+});
diff --git a/packages/svelte/tests/runtime-production/samples/keyed-each-unique-2/main.svelte b/packages/svelte/tests/runtime-production/samples/keyed-each-unique-2/main.svelte
new file mode 100644
index 0000000000..f8ba50d866
--- /dev/null
+++ b/packages/svelte/tests/runtime-production/samples/keyed-each-unique-2/main.svelte
@@ -0,0 +1,8 @@
+<script>
+	let data = $state([1, 2, 3]);
+</script>
+
+<button onclick={() => data = [1, 1, 1]}>add</button>
+{#each data as d (d)}
+	{d}
+{/each}
diff --git a/packages/svelte/tests/runtime-production/samples/keyed-each-unique-3/_config.js b/packages/svelte/tests/runtime-production/samples/keyed-each-unique-3/_config.js
new file mode 100644
index 0000000000..7e1840200a
--- /dev/null
+++ b/packages/svelte/tests/runtime-production/samples/keyed-each-unique-3/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	error: 'each_key_duplicate'
+});
diff --git a/packages/svelte/tests/runtime-production/samples/keyed-each-unique-3/main.svelte b/packages/svelte/tests/runtime-production/samples/keyed-each-unique-3/main.svelte
new file mode 100644
index 0000000000..a05781bcb9
--- /dev/null
+++ b/packages/svelte/tests/runtime-production/samples/keyed-each-unique-3/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	let data = [1, 1, 1];
+</script>
+
+{#each data as d (d)}
+	{d}
+{/each}
diff --git a/packages/svelte/tests/runtime-production/samples/keyed-each-unique/_config.js b/packages/svelte/tests/runtime-production/samples/keyed-each-unique/_config.js
new file mode 100644
index 0000000000..bc945876ea
--- /dev/null
+++ b/packages/svelte/tests/runtime-production/samples/keyed-each-unique/_config.js
@@ -0,0 +1,12 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	test({ assert, target }) {
+		let button = target.querySelector('button');
+
+		button?.click();
+
+		assert.throws(flushSync, 'https://svelte.dev/e/each_key_duplicate');
+	}
+});
diff --git a/packages/svelte/tests/runtime-production/samples/keyed-each-unique/main.svelte b/packages/svelte/tests/runtime-production/samples/keyed-each-unique/main.svelte
new file mode 100644
index 0000000000..3d52179372
--- /dev/null
+++ b/packages/svelte/tests/runtime-production/samples/keyed-each-unique/main.svelte
@@ -0,0 +1,8 @@
+<script>
+	let data = $state([1, 2, 3, 4, 5]);
+</script>
+
+<button onclick={() => data = [1, 1, 3, 1]}>add</button>
+{#each data as d (d)}
+	{d}
+{/each}

From f05f946feafd804de3416742e5d2379651087b2e Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Thu, 5 Feb 2026 09:57:16 -0500
Subject: [PATCH 116/142] fix: add vite-ignore comment inside dynamic crypto
 import (#17623)

---
 .changeset/forty-worlds-attack.md             | 5 +++++
 packages/svelte/src/internal/server/crypto.js | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/forty-worlds-attack.md

diff --git a/.changeset/forty-worlds-attack.md b/.changeset/forty-worlds-attack.md
new file mode 100644
index 0000000000..52bb3644c0
--- /dev/null
+++ b/.changeset/forty-worlds-attack.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: add vite-ignore comment inside dynamic crypto import
diff --git a/packages/svelte/src/internal/server/crypto.js b/packages/svelte/src/internal/server/crypto.js
index 9bb6ecdd39..76d66b6d1a 100644
--- a/packages/svelte/src/internal/server/crypto.js
+++ b/packages/svelte/src/internal/server/crypto.js
@@ -13,7 +13,7 @@ export async function sha256(data) {
 		? globalThis.crypto
 		: // @ts-ignore - we don't install node types in the prod build
 			// don't use 'node:crypto' because static analysers will think we rely on node when we don't
-			(await import('node:' + 'crypto')).webcrypto;
+			(await import(/* @vite-ignore */ 'node:' + 'crypto')).webcrypto;
 
 	const hash_buffer = await crypto.subtle.digest('SHA-256', text_encoder.encode(data));
 

From fcbd3e325a62c4a2c83ff51f721fdfe26b7451d9 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Thu, 5 Feb 2026 09:59:07 -0500
Subject: [PATCH 117/142] feat: allow use of createContext when instantiating
 components programmatically (#17575)

* feat: allow use of createContext when instantiating components programmatically

* docs
---
 .changeset/orange-ants-greet.md               |  5 ++++
 documentation/docs/06-runtime/02-context.md   | 26 +++++++++++++++++++
 packages/svelte/src/internal/client/render.js | 12 +++------
 .../svelte/src/internal/server/renderer.js    | 12 +++------
 .../create-context-programmatic/Child.svelte  |  7 +++++
 .../create-context-programmatic/_config.js    |  8 ++++++
 .../create-context-programmatic/main.svelte   | 20 ++++++++++++++
 7 files changed, 74 insertions(+), 16 deletions(-)
 create mode 100644 .changeset/orange-ants-greet.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/create-context-programmatic/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/create-context-programmatic/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/create-context-programmatic/main.svelte

diff --git a/.changeset/orange-ants-greet.md b/.changeset/orange-ants-greet.md
new file mode 100644
index 0000000000..6f7c684fee
--- /dev/null
+++ b/.changeset/orange-ants-greet.md
@@ -0,0 +1,5 @@
+---
+'svelte': minor
+---
+
+feat: allow use of createContext when instantiating components programmatically
diff --git a/documentation/docs/06-runtime/02-context.md b/documentation/docs/06-runtime/02-context.md
index 0dfb996164..61b203f93e 100644
--- a/documentation/docs/06-runtime/02-context.md
+++ b/documentation/docs/06-runtime/02-context.md
@@ -97,6 +97,32 @@ import { createContext } from 'svelte';
 export const [getUserContext, setUserContext] = createContext<User>();
 ```
 
+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:
+
+```js
+import { mount, unmount } from 'svelte';
+import { expect, test } from 'vitest';
+import { setUserContext } from './context';
+import MyComponent from './MyComponent.svelte';
+
+test('MyComponent', () => {
+	function Wrapper(...args) {
+		setUserContext({ name: 'Bob' });
+		return MyComponent(...args);
+	}
+
+	const component = mount(Wrapper, {
+		target: document.body
+	});
+
+	expect(document.body.innerHTML).toBe('<h1>Hello Bob!</h1>');
+
+	unmount(component);
+});
+```
+
+This approach also works with [`hydrate`](imperative-component-api#hydrate) and [`render`](imperative-component-api#render).
+
 ## 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:
diff --git a/packages/svelte/src/internal/client/render.js b/packages/svelte/src/internal/client/render.js
index c76f0b1ce7..c09f5fdd05 100644
--- a/packages/svelte/src/internal/client/render.js
+++ b/packages/svelte/src/internal/client/render.js
@@ -208,11 +208,9 @@ function _mount(Component, { target, anchor, props = {}, events, context, intro
 				pending: () => {}
 			},
 			(anchor_node) => {
-				if (context) {
-					push({});
-					var ctx = /** @type {ComponentContext} */ (component_context);
-					ctx.c = context;
-				}
+				push({});
+				var ctx = /** @type {ComponentContext} */ (component_context);
+				if (context) ctx.c = context;
 
 				if (events) {
 					// We can't spread the object or else we'd lose the state proxy stuff, if it is one
@@ -241,9 +239,7 @@ function _mount(Component, { target, anchor, props = {}, events, context, intro
 					}
 				}
 
-				if (context) {
-					pop();
-				}
+				pop();
 			}
 		);
 
diff --git a/packages/svelte/src/internal/server/renderer.js b/packages/svelte/src/internal/server/renderer.js
index 65f9bcae6a..49f4c1b7d2 100644
--- a/packages/svelte/src/internal/server/renderer.js
+++ b/packages/svelte/src/internal/server/renderer.js
@@ -617,18 +617,14 @@ export class Renderer {
 
 		renderer.push(BLOCK_OPEN);
 
-		if (options.context) {
-			push();
-			/** @type {SSRContext} */ (ssr_context).c = options.context;
-			/** @type {SSRContext} */ (ssr_context).r = renderer;
-		}
+		push();
+		if (options.context) /** @type {SSRContext} */ (ssr_context).c = options.context;
+		/** @type {SSRContext} */ (ssr_context).r = renderer;
 
 		// @ts-expect-error
 		component(renderer, options.props ?? {});
 
-		if (options.context) {
-			pop();
-		}
+		pop();
 
 		renderer.push(BLOCK_CLOSE);
 
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
new file mode 100644
index 0000000000..3e39d5043e
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/create-context-programmatic/Child.svelte
@@ -0,0 +1,7 @@
+<script>
+	import { get } from './main.svelte';
+
+	const message = get();
+</script>
+
+<h1>{message}</h1>
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
new file mode 100644
index 0000000000..f4374c8759
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/create-context-programmatic/_config.js
@@ -0,0 +1,8 @@
+import { test } from '../../test';
+
+export default test({
+	ssrHtml: `<div></div>`,
+	html: `<div><h1>hello</h1></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
new file mode 100644
index 0000000000..3c42dbf180
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/create-context-programmatic/main.svelte
@@ -0,0 +1,20 @@
+<script module>
+	import { createContext, mount } from 'svelte';
+	import Child from './Child.svelte';
+
+	/** @type {ReturnType<typeof createContext<string>>} */
+	const [get, set] = createContext();
+
+	export { get };
+
+	function Wrapper(Component) {
+		return (...args) => {
+			set('hello');
+			return Component(...args);
+		};
+	}
+</script>
+
+<div {@attach (target) => {
+	mount(Wrapper(Child), { target });
+}}></div>

From 3970e7a302e29fa09eb3c0351301f260401e32f0 Mon Sep 17 00:00:00 2001
From: Elliott Johnson <sejohnson@torchcloudconsulting.com>
Date: Thu, 5 Feb 2026 13:58:50 -0700
Subject: [PATCH 118/142] chore: fix pkg.pr.new workflow (#17633)

---
 .github/workflows/pkg.pr.new-comment.yml | 115 -------------
 .github/workflows/pkg.pr.new.yml         | 205 +++++++++++++++++++++--
 2 files changed, 190 insertions(+), 130 deletions(-)
 delete mode 100644 .github/workflows/pkg.pr.new-comment.yml

diff --git a/.github/workflows/pkg.pr.new-comment.yml b/.github/workflows/pkg.pr.new-comment.yml
deleted file mode 100644
index 64495cc5c8..0000000000
--- a/.github/workflows/pkg.pr.new-comment.yml
+++ /dev/null
@@ -1,115 +0,0 @@
-name: Update pkg.pr.new comment
-
-on:
-  workflow_run:
-    workflows: ['Publish Any Commit']
-    types:
-      - completed
-
-permissions:
-  pull-requests: write
-
-jobs:
-  build:
-    name: 'Update comment'
-    runs-on: ubuntu-latest
-    steps:
-      - name: Download artifact
-        uses: actions/download-artifact@v7
-        with:
-          name: output
-          github-token: ${{ secrets.GITHUB_TOKEN }}
-          run-id: ${{ github.event.workflow_run.id }}
-
-      - run: ls -R .
-      - name: 'Post or update comment'
-        uses: actions/github-script@v8
-        with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}
-          script: |
-            const fs = require('fs');
-            const output = JSON.parse(fs.readFileSync('output.json', 'utf8'));
-
-            const bot_comment_identifier = `<!-- pkg.pr.new comment -->`;
-
-            const body = (number) => `${bot_comment_identifier}
-
-            [Playground](https://svelte.dev/playground?version=pr-${number})
-
-            \`\`\`
-            ${output.packages.map((p) => `pnpm add https://pkg.pr.new/${p.name}@${number}`).join('\n')}
-            \`\`\`
-            `;
-
-            async function find_bot_comment(issue_number) {
-              if (!issue_number) return null;
-              const comments = await github.rest.issues.listComments({
-                owner: context.repo.owner,
-                repo: context.repo.repo,
-                issue_number: issue_number,
-              });
-              return comments.data.find((comment) =>
-                comment.body.includes(bot_comment_identifier)
-              );
-            }
-
-            async function create_or_update_comment(issue_number) {
-              if (!issue_number) {
-                console.log('No issue number provided. Cannot post or update comment.');
-                return;
-              }
-
-              const existing_comment = await find_bot_comment(issue_number);
-              if (existing_comment) {
-                await github.rest.issues.updateComment({
-                  owner: context.repo.owner,
-                  repo: context.repo.repo,
-                  comment_id: existing_comment.id,
-                  body: body(issue_number),
-                });
-              } else {
-                await github.rest.issues.createComment({
-                  issue_number: issue_number,
-                  owner: context.repo.owner,
-                  repo: context.repo.repo,
-                  body: body(issue_number),
-                });
-              }
-            }
-
-            async function log_publish_info() {
-              const svelte_package = output.packages.find(p => p.name === 'svelte');
-              const svelte_sha = svelte_package.url.replace(/^.+@([^@]+)$/, '$1');
-              console.log('\n' + '='.repeat(50));
-              console.log('Publish Information');
-              console.log('='.repeat(50));
-              console.log('\nPublished Packages:');
-              console.log(output.packages.map((p) => `${p.name} - pnpm add https://pkg.pr.new/${p.name}@${p.url.replace(/^.+@([^@]+)$/, '$1')}`).join('\n'));
-              if(svelte_sha){
-                console.log('\nPlayground URL:');
-                console.log(`\nhttps://svelte.dev/playground?version=commit-${svelte_sha}`)
-              }
-              console.log('\n' + '='.repeat(50));
-            }
-
-            if (output.event_name === 'pull_request') {
-              if (output.number) {
-                await create_or_update_comment(output.number);
-              }
-            } else if (output.event_name === 'push') {
-              const pull_requests = await github.rest.pulls.list({
-                owner: context.repo.owner,
-                repo: context.repo.repo,
-                state: 'open',
-                head: `${context.repo.owner}:${output.ref.replace('refs/heads/', '')}`,
-              });
-
-              if (pull_requests.data.length > 0) {
-                await create_or_update_comment(pull_requests.data[0].number);
-              } else {
-                console.log(
-                  'No open pull request found for this push. Logging publish information to console:'
-                );
-                await log_publish_info();
-              }
-            }
diff --git a/.github/workflows/pkg.pr.new.yml b/.github/workflows/pkg.pr.new.yml
index 252cbed769..51b7472911 100644
--- a/.github/workflows/pkg.pr.new.yml
+++ b/.github/workflows/pkg.pr.new.yml
@@ -1,16 +1,51 @@
-name: Publish Any Commit
-on: [push, pull_request]
+name: pkg.pr.new
+on:
+  pull_request_target:
+    types: [opened, synchronize]
+  push:
+    branches: [main]
 
 permissions: {}
 
 jobs:
-  build:
-    permissions: {}
+  # This job determines the environment to use for the build job. It ensures that:
+  # - For pushes to main, we use the "Publish pkg.pr.new (maintainers)" environment.
+  # - For PRs from the same repository, we also use the "Publish pkg.pr.new (maintainers)" environment, since these are trusted.
+  # - For PRs from forks, we use the "Publish pkg.pr.new (external contributors)" environment, which requires manual approval by a maintainer before the build job can run.
+  #   This protects us from running untrusted code while still allowing external contributors to use pkg.pr.new.
+  resolve-env:
+    runs-on: ubuntu-latest
+    outputs:
+      environment: ${{ steps.resolve.outputs.environment }}
+    steps:
+      - name: Determine environment
+        id: resolve
+        run: |
+          if [[ "${{ github.event_name }}" == "push" ]]; then
+            echo "environment=Publish pkg.pr.new (maintainers)" >> "$GITHUB_OUTPUT"
+          elif [[ "${{ github.event.pull_request.head.repo.full_name }}" == "${{ github.repository }}" ]]; then
+            echo "environment=Publish pkg.pr.new (maintainers)" >> "$GITHUB_OUTPUT"
+          else
+            echo "environment=Publish pkg.pr.new (external contributors)" >> "$GITHUB_OUTPUT"
+          fi
 
+  build:
+    needs: resolve-env
     runs-on: ubuntu-latest
+    # This is the line that ensures forks require manual approval before running the build job
+    environment: ${{ needs.resolve-env.outputs.environment }}
+
+    # No permissions — this job runs user-controlled code
+    permissions: {}
 
     steps:
       - uses: actions/checkout@v6
+        with:
+          # For pull_request_target, we must explicitly check out the PR head.
+          # This is safe because the environment gate above has already fired —
+          # an org member has approved this specific commit for external PRs.
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
+
       - uses: pnpm/action-setup@v4
       - uses: actions/setup-node@v6
         with:
@@ -24,21 +59,161 @@ jobs:
         run: pnpm build
 
       - run: pnpx pkg-pr-new publish --comment=off --json output.json --compact --no-template './packages/svelte'
-      - name: Add metadata to output
+
+      - 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]{6}$/;
+
+            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'
+    runs-on: ubuntu-latest
+
+    permissions:
+      pull-requests: write
+
+    steps:
+      - name: Download sanitized artifact
+        uses: actions/download-artifact@v7
+        with:
+          name: sanitized-output
+
+      - name: Post or update comment
         uses: actions/github-script@v8
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           script: |
             const fs = require('fs');
-            const output = JSON.parse(fs.readFileSync('output.json', 'utf8'));
-            output.number = context.issue.number;
-            output.event_name = context.eventName;
-            output.ref = context.ref;
-            fs.writeFileSync('output.json', JSON.stringify(output), 'utf8');
-      - name: Upload output
-        uses: actions/upload-artifact@v6
+            const { packages } = JSON.parse(fs.readFileSync('sanitized-output.json', 'utf8'));
+
+            if (packages.length === 0) {
+              console.log('No valid packages found. Skipping comment.');
+              return;
+            }
+
+            // Issue number from trusted event context, never from the artifact
+            const issue_number = context.issue.number;
+
+            const bot_comment_identifier = `<!-- pkg.pr.new comment -->`;
+
+            const body = `${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: output
-          path: ./output.json
+          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;
+            }
 
-      - run: ls -R .
+            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));

From 660c4c12b1e1c50d067dfd800465bea21d29651f Mon Sep 17 00:00:00 2001
From: Elliott Johnson <sejohnson@torchcloudconsulting.com>
Date: Thu, 5 Feb 2026 14:04:56 -0700
Subject: [PATCH 119/142] chore: off-by-one in workflow (#17634)

---
 .github/workflows/pkg.pr.new.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/pkg.pr.new.yml b/.github/workflows/pkg.pr.new.yml
index 51b7472911..0f0c433361 100644
--- a/.github/workflows/pkg.pr.new.yml
+++ b/.github/workflows/pkg.pr.new.yml
@@ -89,7 +89,7 @@ jobs:
             const raw = JSON.parse(fs.readFileSync('output.json', 'utf8'));
 
             const ALLOWED_PACKAGES = new Set(['svelte']);
-            const SHA_PATTERN = /^[0-9a-f]{6}$/;
+            const SHA_PATTERN = /^[0-9a-f]{7}$/;
 
             const packages = (raw.packages || [])
               .filter(p => {

From a75866f34d5b64e0c40b2888a5f89a69ec1151f9 Mon Sep 17 00:00:00 2001
From: Artyom Alekseevich <47069814+FrankFMY@users.noreply.github.com>
Date: Thu, 5 Feb 2026 23:03:40 +0100
Subject: [PATCH 120/142] fix: detect store in each block expression regardless
 of AST shape (#17636)

The store invalidation detection in each blocks only checked for
Identifier and MemberExpression AST node types. This caused bind:
on iteration variables to silently fail when the expression used
logical operators (e.g. `{#each $store.items ?? [] as item}`).

Use expression metadata dependencies instead of AST type checking
to find store_sub bindings, which correctly handles all expression
shapes.

Fixes #14625
---
 .changeset/fix-each-bind-store-logical.md     |  5 +++++
 .../3-transform/client/visitors/EachBlock.js  | 12 ++++------
 .../store-each-binding-logical/_config.js     | 22 +++++++++++++++++++
 .../store-each-binding-logical/main.svelte    | 13 +++++++++++
 4 files changed, 44 insertions(+), 8 deletions(-)
 create mode 100644 .changeset/fix-each-bind-store-logical.md
 create mode 100644 packages/svelte/tests/runtime-legacy/samples/store-each-binding-logical/_config.js
 create mode 100644 packages/svelte/tests/runtime-legacy/samples/store-each-binding-logical/main.svelte

diff --git a/.changeset/fix-each-bind-store-logical.md b/.changeset/fix-each-bind-store-logical.md
new file mode 100644
index 0000000000..1327015124
--- /dev/null
+++ b/.changeset/fix-each-bind-store-logical.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: detect store in each block expression regardless of AST shape
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 b2724fa90f..a1371b516a 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
@@ -101,15 +101,11 @@ export function EachBlock(node, context) {
 	}
 
 	// If the array is a store expression, we need to invalidate it when the array is changed.
-	// This doesn't catch all cases, but all the ones that Svelte 4 catches, too.
 	let store_to_invalidate = '';
-	if (node.expression.type === 'Identifier' || node.expression.type === 'MemberExpression') {
-		const id = object(node.expression);
-		if (id) {
-			const binding = context.state.scope.get(id.name);
-			if (binding?.kind === 'store_sub') {
-				store_to_invalidate = id.name;
-			}
+	for (const binding of node.metadata.expression.dependencies) {
+		if (binding.kind === 'store_sub') {
+			store_to_invalidate = binding.node.name;
+			break;
 		}
 	}
 
diff --git a/packages/svelte/tests/runtime-legacy/samples/store-each-binding-logical/_config.js b/packages/svelte/tests/runtime-legacy/samples/store-each-binding-logical/_config.js
new file mode 100644
index 0000000000..1134b20d0c
--- /dev/null
+++ b/packages/svelte/tests/runtime-legacy/samples/store-each-binding-logical/_config.js
@@ -0,0 +1,22 @@
+import { flushSync } from 'svelte';
+import { ok, test } from '../../test';
+
+export default test({
+	test({ assert, target, window }) {
+		const input = target.querySelector('input');
+		ok(input);
+
+		const event = new window.Event('input');
+		input.value = 'changed';
+		input.dispatchEvent(event);
+		flushSync();
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+			<input>
+			<p>changed</p>
+		`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-legacy/samples/store-each-binding-logical/main.svelte b/packages/svelte/tests/runtime-legacy/samples/store-each-binding-logical/main.svelte
new file mode 100644
index 0000000000..77731ea5a4
--- /dev/null
+++ b/packages/svelte/tests/runtime-legacy/samples/store-each-binding-logical/main.svelte
@@ -0,0 +1,13 @@
+<script>
+	import { writable } from 'svelte/store';
+
+	const items = writable([
+		{ id: 0, text: 'initial' }
+	]);
+</script>
+
+{#each $items ?? [] as item}
+	<input bind:value={item.text}>
+{/each}
+
+<p>{$items[0].text}</p>

From f5304ec8c944b1893e8150449d26cf07af910d7b Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 6 Feb 2026 04:11:26 -0500
Subject: [PATCH 121/142] chore: simplify SSR code (#17639)

creates a few abstractions in the compiler code around common "if-else" scenarios, as well as introducing a new runtime render helper

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .../3-transform/client/visitors/Fragment.js   |  40 +++---
 .../3-transform/server/transform-server.js    |  11 +-
 .../phases/3-transform/server/types.d.ts      |   3 +-
 .../3-transform/server/visitors/AwaitBlock.js |  15 ++-
 .../3-transform/server/visitors/EachBlock.js  |  30 ++---
 .../3-transform/server/visitors/Fragment.js   |   2 +-
 .../3-transform/server/visitors/HtmlTag.js    |  25 ++--
 .../3-transform/server/visitors/IfBlock.js    |  21 ++--
 .../server/visitors/RegularElement.js         |  55 ++------
 .../3-transform/server/visitors/RenderTag.js  |  14 +--
 .../server/visitors/SlotElement.js            |  11 +-
 .../server/visitors/SvelteElement.js          |  53 +++-----
 .../server/visitors/shared/component.js       |  41 ++----
 .../server/visitors/shared/utils.js           | 118 +++++++++---------
 .../svelte/src/internal/server/renderer.js    |   9 ++
 .../_expected/server/index.svelte.js          |   6 +-
 .../_expected/server/index.svelte.js          |   2 +-
 .../_expected/server/index.svelte.js          |   2 +-
 .../_expected/server/index.svelte.js          |   2 +-
 .../_expected/server/index.svelte.js          |   2 +-
 .../_expected/server/index.svelte.js          |   6 +-
 21 files changed, 184 insertions(+), 284 deletions(-)

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 79a443967c..f463111c4d 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
@@ -120,34 +120,32 @@ export function Fragment(node, context) {
 
 			state.init.unshift(b.var(id, b.call('$.text')));
 			close = b.stmt(b.call('$.append', b.id('$$anchor'), id));
+		} else if (is_standalone) {
+			// no need to create a template, we can just use the existing block's anchor
+			process_children(trimmed, () => b.id('$$anchor'), false, { ...context, state });
 		} else {
-			if (is_standalone) {
-				// no need to create a template, we can just use the existing block's anchor
-				process_children(trimmed, () => b.id('$$anchor'), false, { ...context, state });
-			} else {
-				/** @type {(is_text: boolean) => Expression} */
-				const expression = (is_text) => b.call('$.first_child', id, is_text && b.true);
-
-				process_children(trimmed, expression, false, { ...context, state });
+			/** @type {(is_text: boolean) => Expression} */
+			const expression = (is_text) => b.call('$.first_child', id, is_text && b.true);
 
-				let flags = TEMPLATE_FRAGMENT;
+			process_children(trimmed, expression, false, { ...context, state });
 
-				if (state.template.needs_import_node) {
-					flags |= TEMPLATE_USE_IMPORT_NODE;
-				}
+			let flags = TEMPLATE_FRAGMENT;
 
-				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 = transform_template(state, namespace, flags);
-					state.hoisted.push(b.var(template_name, template));
+			if (state.template.needs_import_node) {
+				flags |= TEMPLATE_USE_IMPORT_NODE;
+			}
 
-					state.init.unshift(b.var(id, b.call(template_name)));
-				}
+			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 = transform_template(state, namespace, flags);
+				state.hoisted.push(b.var(template_name, template));
 
-				close = b.stmt(b.call('$.append', b.id('$$anchor'), id));
+				state.init.unshift(b.var(id, b.call(template_name)));
 			}
+
+			close = b.stmt(b.call('$.append', b.id('$$anchor'), id));
 		}
 	}
 
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js b/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
index 0e2f68d0f5..b9f1441bff 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
@@ -41,7 +41,6 @@ import { TitleElement } from './visitors/TitleElement.js';
 import { UpdateExpression } from './visitors/UpdateExpression.js';
 import { VariableDeclaration } from './visitors/VariableDeclaration.js';
 import { SvelteBoundary } from './visitors/SvelteBoundary.js';
-import { call_component_renderer } from './visitors/shared/utils.js';
 
 /** @type {Visitors} */
 const global_visitors = {
@@ -105,7 +104,7 @@ export function server_component(analysis, options) {
 		namespace: options.namespace,
 		preserve_whitespace: options.preserveWhitespace,
 		state_fields: new Map(),
-		skip_hydration_boundaries: false,
+		is_standalone: false,
 		is_instance: false
 	};
 
@@ -260,7 +259,13 @@ export function server_component(analysis, options) {
 
 	if (should_inject_context) {
 		component_block = b.block([
-			call_component_renderer(component_block, dev && b.id(component_name))
+			b.stmt(
+				b.call(
+					'$$renderer.component',
+					b.arrow([b.id('$$renderer')], component_block, false),
+					dev && b.id(component_name)
+				)
+			)
 		]);
 	}
 
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 e7a72fb8ad..4912728a1e 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
@@ -26,7 +26,8 @@ export interface ComponentServerTransformState extends ServerTransformState {
 	readonly template: Array<Statement | Expression>;
 	readonly namespace: Namespace;
 	readonly preserve_whitespace: boolean;
-	readonly skip_hydration_boundaries: 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 */
 	async_consts?: {
 		id: Identifier;
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 b8d2e42144..84c2a81612 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
@@ -2,7 +2,7 @@
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types.js' */
 import * as b from '#compiler/builders';
-import { block_close, create_async_block } from './shared/utils.js';
+import { block_close, create_child_block } from './shared/utils.js';
 
 /**
  * @param {AST.AwaitBlock} node
@@ -25,13 +25,12 @@ export function AwaitBlock(node, context) {
 		)
 	);
 
-	if (node.metadata.expression.is_async()) {
-		statement = create_async_block(
-			b.block([statement]),
+	context.state.template.push(
+		...create_child_block(
+			[statement],
 			node.metadata.expression.blockers(),
 			node.metadata.expression.has_await
-		);
-	}
-
-	context.state.template.push(statement, block_close);
+		),
+		block_close
+	);
 }
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 3c0a8c1676..cb5a61d52f 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 +2,7 @@
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types.js' */
 import * as b from '#compiler/builders';
-import { block_close, block_open, block_open_else, create_async_block } from './shared/utils.js';
+import { block_close, block_open, block_open_else, create_child_block } from './shared/utils.js';
 
 /**
  * @param {AST.EachBlock} node
@@ -18,8 +18,8 @@ export function EachBlock(node, context) {
 
 	const array_id = state.scope.root.unique('each_array');
 
-	/** @type {Statement} */
-	let block = b.block([b.const(array_id, b.call('$.ensure_array_like', collection))]);
+	/** @type {Statement[]} */
+	let statements = [b.const(array_id, b.call('$.ensure_array_like', collection))];
 
 	/** @type {Statement[]} */
 	const each = [];
@@ -53,7 +53,7 @@ export function EachBlock(node, context) {
 
 		fallback.body.unshift(b.stmt(b.call(b.id('$$renderer.push'), block_open_else)));
 
-		block.body.push(
+		statements.push(
 			b.if(
 				b.binary('!==', b.member(array_id, 'length'), b.literal(0)),
 				b.block([open, for_loop]),
@@ -62,19 +62,15 @@ export function EachBlock(node, context) {
 		);
 	} else {
 		state.template.push(block_open);
-		block.body.push(for_loop);
+		statements.push(for_loop);
 	}
 
-	if (node.metadata.expression.is_async()) {
-		state.template.push(
-			create_async_block(
-				block,
-				node.metadata.expression.blockers(),
-				node.metadata.expression.has_await
-			),
-			block_close
-		);
-	} else {
-		state.template.push(...block.body, block_close);
-	}
+	state.template.push(
+		...create_child_block(
+			statements,
+			node.metadata.expression.blockers(),
+			node.metadata.expression.has_await
+		),
+		block_close
+	);
 }
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/Fragment.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/Fragment.js
index ef5bd985ae..a6ff33c7ab 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/Fragment.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/Fragment.js
@@ -28,7 +28,7 @@ export function Fragment(node, context) {
 		init: [],
 		template: [],
 		namespace,
-		skip_hydration_boundaries: is_standalone,
+		is_standalone,
 		async_consts: undefined
 	};
 
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/HtmlTag.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/HtmlTag.js
index 3f423fa60d..ee790c3e7c 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/HtmlTag.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/HtmlTag.js
@@ -2,25 +2,24 @@
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types.js' */
 import * as b from '#compiler/builders';
-import { block_close, block_open, create_push } from './shared/utils.js';
+import { create_child_block } from './shared/utils.js';
 
 /**
  * @param {AST.HtmlTag} node
  * @param {ComponentContext} context
  */
 export function HtmlTag(node, context) {
-	const expression = /** @type {Expression} */ (context.visit(node.expression));
-	const call = b.call('$.html', expression);
+	const expression = b.call('$.html', /** @type {Expression} */ (context.visit(node.expression)));
 
-	const has_await = node.metadata.expression.has_await;
-
-	if (has_await) {
-		context.state.template.push(block_open);
-	}
-
-	context.state.template.push(create_push(call, node.metadata.expression, true));
-
-	if (has_await) {
-		context.state.template.push(block_close);
+	if (node.metadata.expression.is_async()) {
+		context.state.template.push(
+			...create_child_block(
+				[b.stmt(b.call('$$renderer.push', expression))],
+				node.metadata.expression.blockers(),
+				node.metadata.expression.has_await
+			)
+		);
+	} else {
+		context.state.template.push(expression);
 	}
 }
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 e8418343be..06b1b1e966 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, block_open, block_open_else, create_async_block } from './shared/utils.js';
+import { block_close, block_open, block_open_else, create_child_block } from './shared/utils.js';
 
 /**
  * @param {AST.IfBlock} node
@@ -23,17 +23,12 @@ export function IfBlock(node, context) {
 	/** @type {Statement} */
 	let statement = b.if(test, consequent, alternate);
 
-	const is_async = node.metadata.expression.is_async();
-
-	const has_await = node.metadata.expression.has_await;
-
-	if (is_async || has_await) {
-		statement = create_async_block(
-			b.block([statement]),
+	context.state.template.push(
+		...create_child_block(
+			[statement],
 			node.metadata.expression.blockers(),
-			!!has_await
-		);
-	}
-
-	context.state.template.push(statement, block_close);
+			node.metadata.expression.has_await
+		),
+		block_close
+	);
 }
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 5b905752f4..1c6bb0a198 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
@@ -1,5 +1,4 @@
 /** @import { Expression } from 'estree' */
-/** @import { Location } from 'locate-character' */
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext, ComponentServerTransformState } from '../types.js' */
 /** @import { Scope } from '../../../scope.js' */
@@ -8,13 +7,7 @@ import { dev, locator } from '../../../../state.js';
 import * as b from '#compiler/builders';
 import { clean_nodes, determine_namespace_for_children } from '../../utils.js';
 import { build_element_attributes, prepare_element_spread_object } from './shared/element.js';
-import {
-	process_children,
-	build_template,
-	create_child_block,
-	PromiseOptimiser,
-	create_async_block
-} from './shared/utils.js';
+import { process_children, build_template, PromiseOptimiser } from './shared/utils.js';
 import { is_customizable_select_element } from '../../../nodes.js';
 
 /**
@@ -66,17 +59,9 @@ export function RegularElement(node, context) {
 			b.literal(`</${node.name}>`)
 		);
 
-		// TODO this is a real edge case, would be good to DRY this out
-		if (optimiser.expressions.length > 0) {
-			context.state.template.push(
-				create_child_block(
-					b.block([optimiser.apply(), ...state.init, ...build_template(state.template)])
-				)
-			);
-		} else {
-			context.state.init.push(...state.init);
-			context.state.template.push(...state.template);
-		}
+		context.state.template.push(
+			...optimiser.render([...state.init, ...build_template(state.template)])
+		);
 
 		return;
 	}
@@ -130,13 +115,7 @@ export function RegularElement(node, context) {
 
 		const statement = b.stmt(b.call('$$renderer.select', attributes, fn, ...rest));
 
-		if (optimiser.expressions.length > 0) {
-			context.state.template.push(
-				create_child_block(b.block([optimiser.apply(), ...state.init, statement]))
-			);
-		} else {
-			context.state.template.push(...state.init, statement);
-		}
+		context.state.template.push(...optimiser.render([...state.init, statement]));
 
 		return;
 	}
@@ -183,13 +162,7 @@ export function RegularElement(node, context) {
 
 		const statement = b.stmt(b.call('$$renderer.option', attributes, body, ...rest));
 
-		if (optimiser.expressions.length > 0) {
-			context.state.template.push(
-				create_child_block(b.block([optimiser.apply(), ...state.init, statement]))
-			);
-		} else {
-			context.state.template.push(...state.init, statement);
-		}
+		context.state.template.push(...optimiser.render([...state.init, statement]));
 
 		return;
 	}
@@ -235,19 +208,9 @@ export function RegularElement(node, context) {
 	}
 
 	if (optimiser.is_async()) {
-		let statements = [...state.init, ...build_template(state.template)];
-
-		if (optimiser.has_await) {
-			statements = [create_child_block(b.block([optimiser.apply(), ...statements]))];
-		}
-
-		const blockers = optimiser.blockers();
-
-		if (blockers.elements.length > 0) {
-			statements = [create_async_block(b.block(statements), blockers, false, false)];
-		}
-
-		context.state.template.push(...statements);
+		context.state.template.push(
+			...optimiser.render([...state.init, ...build_template(state.template)])
+		);
 	} else {
 		context.state.init.push(...state.init);
 		context.state.template.push(...state.template);
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/RenderTag.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/RenderTag.js
index 6d7cef0d95..fe20e85e1b 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/RenderTag.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/RenderTag.js
@@ -3,7 +3,7 @@
 /** @import { ComponentContext } from '../types.js' */
 import { unwrap_optional } from '../../../../utils/ast.js';
 import * as b from '#compiler/builders';
-import { create_async_block, empty_comment, PromiseOptimiser } from './shared/utils.js';
+import { empty_comment, PromiseOptimiser } from './shared/utils.js';
 
 /**
  * @param {AST.RenderTag} node
@@ -35,17 +35,9 @@ export function RenderTag(node, context) {
 		)
 	);
 
-	if (optimiser.is_async()) {
-		statement = create_async_block(
-			b.block([optimiser.apply(), statement]),
-			optimiser.blockers(),
-			optimiser.has_await
-		);
-	}
-
-	context.state.template.push(statement);
+	context.state.template.push(...optimiser.render_block([statement]));
 
-	if (!context.state.skip_hydration_boundaries) {
+	if (!context.state.is_standalone) {
 		context.state.template.push(empty_comment);
 	}
 }
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SlotElement.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SlotElement.js
index d0f8e25d02..3cebdf4541 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SlotElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SlotElement.js
@@ -5,7 +5,6 @@ import * as b from '#compiler/builders';
 import {
 	build_attribute_value,
 	PromiseOptimiser,
-	create_async_block,
 	block_open,
 	block_close
 } from './shared/utils.js';
@@ -65,13 +64,5 @@ export function SlotElement(node, context) {
 		fallback
 	);
 
-	const statement = optimiser.is_async()
-		? create_async_block(
-				b.block([optimiser.apply(), b.stmt(slot)]),
-				optimiser.blockers(),
-				optimiser.has_await
-			)
-		: b.stmt(slot);
-
-	context.state.template.push(block_open, statement, block_close);
+	context.state.template.push(block_open, ...optimiser.render_block([b.stmt(slot)]), block_close);
 }
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js
index 75ba323e20..398ecc68a2 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js
@@ -1,4 +1,3 @@
-/** @import { Location } from 'locate-character' */
 /** @import { BlockStatement, Expression, Statement } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types.js' */
@@ -6,12 +5,7 @@ import { dev, locator } from '../../../../state.js';
 import * as b from '#compiler/builders';
 import { determine_namespace_for_children } from '../../utils.js';
 import { build_element_attributes } from './shared/element.js';
-import {
-	build_template,
-	create_async_block,
-	create_child_block,
-	PromiseOptimiser
-} from './shared/utils.js';
+import { build_template, create_child_block, PromiseOptimiser } from './shared/utils.js';
 
 /**
  * @param {AST.SvelteElement} node
@@ -67,36 +61,29 @@ export function SvelteElement(node, context) {
 	const attributes = b.block([...state.init, ...build_template(state.template)]);
 	const children = /** @type {BlockStatement} */ (context.visit(node.fragment, state));
 
-	/** @type {Statement} */
-	let statement = b.stmt(
-		b.call(
-			'$.element',
-			b.id('$$renderer'),
-			tag,
-			attributes.body.length > 0 && b.thunk(attributes),
-			children.body.length > 0 && b.thunk(children)
-		)
+	statements.push(
+		...optimiser.render([
+			b.stmt(
+				b.call(
+					'$.element',
+					b.id('$$renderer'),
+					tag,
+					attributes.body.length > 0 && b.thunk(attributes),
+					children.body.length > 0 && b.thunk(children)
+				)
+			)
+		])
 	);
 
-	if (optimiser.expressions.length > 0) {
-		statement = create_child_block(b.block([optimiser.apply(), statement]));
-	}
-
-	statements.push(statement);
-
 	if (dev) {
 		statements.push(b.stmt(b.call('$.pop_element')));
 	}
 
-	if (node.metadata.expression.is_async()) {
-		statements = [
-			create_async_block(
-				b.block(statements),
-				node.metadata.expression.blockers(),
-				node.metadata.expression.has_await
-			)
-		];
-	}
-
-	context.state.template.push(...statements);
+	context.state.template.push(
+		...create_child_block(
+			statements,
+			node.metadata.expression.blockers(),
+			node.metadata.expression.has_await
+		)
+	);
 }
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/component.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/component.js
index cfd9a27d7b..fe49a67b28 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/component.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/component.js
@@ -1,12 +1,7 @@
 /** @import { BlockStatement, Expression, Pattern, Property, SequenceExpression, Statement } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../../types.js' */
-import {
-	empty_comment,
-	build_attribute_value,
-	create_async_block,
-	PromiseOptimiser
-} from './utils.js';
+import { empty_comment, build_attribute_value, PromiseOptimiser } from './utils.js';
 import * as b from '#compiler/builders';
 import { is_element_node } from '../../../../nodes.js';
 import { dev } from '../../../../../state.js';
@@ -325,32 +320,16 @@ export function build_inline_component(node, expression, context) {
 		optimiser.check_blockers(node.metadata.expression);
 	}
 
-	const is_async = optimiser.is_async();
-
-	if (is_async) {
-		statement = create_async_block(
-			b.block([
-				optimiser.apply(),
-				dynamic && custom_css_props.length === 0
-					? b.stmt(b.call('$$renderer.push', empty_comment))
-					: b.empty,
-				statement
-			]),
-			optimiser.blockers(),
-			optimiser.has_await
-		);
-	} else if (dynamic && custom_css_props.length === 0) {
-		context.state.template.push(empty_comment);
-	}
-
-	context.state.template.push(statement);
+	context.state.template.push(
+		...optimiser.render_block([
+			dynamic && custom_css_props.length === 0
+				? b.stmt(b.call('$$renderer.push', empty_comment))
+				: b.empty,
+			statement
+		])
+	);
 
-	if (
-		!is_async &&
-		!context.state.skip_hydration_boundaries &&
-		custom_css_props.length === 0 &&
-		optimiser.expressions.length === 0
-	) {
+	if (!optimiser.is_async() && !context.state.is_standalone && custom_css_props.length === 0) {
 		context.state.template.push(empty_comment);
 	}
 }
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 b02a935ed2..ee14a4d135 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
@@ -81,7 +81,19 @@ export function process_children(nodes, { visit, state }) {
 			flush();
 
 			const expression = /** @type {Expression} */ (visit(node.expression));
-			state.template.push(create_push(b.call('$.escape', expression), node.metadata.expression));
+
+			let call = b.call(
+				'$$renderer.push',
+				b.thunk(b.call('$.escape', expression), node.metadata.expression.has_await)
+			);
+
+			const blockers = node.metadata.expression.blockers();
+
+			if (blockers.elements.length > 0) {
+				call = b.call('$$renderer.async', blockers, b.arrow([b.id('$$renderer')], call));
+			}
+
+			state.template.push(b.stmt(call));
 		} else if (node.type === 'Text' || node.type === 'Comment' || node.type === 'ExpressionTag') {
 			sequence.push(node);
 		} else {
@@ -262,72 +274,20 @@ export function build_getter(node, state) {
 }
 
 /**
- * Creates a `$$renderer.child(...)` expression statement
- * @param {BlockStatement | Expression} body
- * @returns {Statement}
- */
-export function create_child_block(body) {
-	return b.stmt(b.call('$$renderer.child', b.arrow([b.id('$$renderer')], body, true)));
-}
-
-/**
- * Creates a `$$renderer.async(...)` expression statement
- * @param {BlockStatement | Expression} body
+ * @param {Statement[]} statements
  * @param {ArrayExpression} blockers
  * @param {boolean} has_await
- * @param {boolean} needs_hydration_markers
  */
-export function create_async_block(
-	body,
-	blockers = b.array([]),
-	has_await = true,
-	needs_hydration_markers = true
-) {
-	return b.stmt(
-		b.call(
-			needs_hydration_markers ? '$$renderer.async_block' : '$$renderer.async',
-			blockers,
-			b.arrow([b.id('$$renderer')], body, has_await)
-		)
-	);
-}
-
-/**
- * @param {Expression} expression
- * @param {ExpressionMetadata} metadata
- * @param {boolean} needs_hydration_markers
- * @returns {Expression | Statement}
- */
-export function create_push(expression, metadata, needs_hydration_markers = false) {
-	if (metadata.is_async()) {
-		let statement = b.stmt(b.call('$$renderer.push', b.thunk(expression, metadata.has_await)));
-
-		const blockers = metadata.blockers();
-
-		if (blockers.elements.length > 0) {
-			statement = create_async_block(
-				b.block([statement]),
-				blockers,
-				false,
-				needs_hydration_markers
-			);
-		}
-
-		return statement;
+export function create_child_block(statements, blockers, has_await) {
+	if (blockers.elements.length === 0 && !has_await) {
+		return statements;
 	}
 
-	return expression;
-}
+	const fn = b.arrow([b.id('$$renderer')], b.block(statements), has_await);
 
-/**
- * @param {BlockStatement | Expression} body
- * @param {Identifier | false} component_fn_id
- * @returns {Statement}
- */
-export function call_component_renderer(body, component_fn_id) {
-	return b.stmt(
-		b.call('$$renderer.component', b.arrow([b.id('$$renderer')], body, false), component_fn_id)
-	);
+	return blockers.elements.length > 0
+		? [b.stmt(b.call('$$renderer.async_block', blockers, fn))]
+		: [b.stmt(b.call('$$renderer.child_block', fn))];
 }
 
 /**
@@ -373,7 +333,7 @@ export class PromiseOptimiser {
 		}
 	}
 
-	apply() {
+	#apply() {
 		if (this.expressions.length === 0) {
 			return b.empty;
 		}
@@ -403,4 +363,38 @@ export class PromiseOptimiser {
 	is_async() {
 		return this.expressions.length > 0 || this.#blockers.size > 0;
 	}
+
+	/**
+	 * @param {Statement[]} statements
+	 * @returns {Statement[]}
+	 */
+	render(statements) {
+		if (!this.is_async()) {
+			return statements;
+		}
+
+		const fn = b.arrow(
+			[b.id('$$renderer')],
+			b.block([this.#apply(), ...statements]),
+			this.has_await
+		);
+
+		const blockers = this.blockers();
+
+		return blockers.elements.length > 0
+			? [b.stmt(b.call('$$renderer.async', blockers, fn))]
+			: [b.stmt(b.call('$$renderer.child', fn))];
+	}
+
+	/**
+	 * @param {Statement[]} statements
+	 * @returns {Statement[]}
+	 */
+	render_block(statements) {
+		if (!this.is_async()) {
+			return statements;
+		}
+
+		return create_child_block([this.#apply(), ...statements], this.blockers(), this.has_await);
+	}
 }
diff --git a/packages/svelte/src/internal/server/renderer.js b/packages/svelte/src/internal/server/renderer.js
index 49f4c1b7d2..62196350bf 100644
--- a/packages/svelte/src/internal/server/renderer.js
+++ b/packages/svelte/src/internal/server/renderer.js
@@ -171,6 +171,15 @@ export class Renderer {
 		return promises;
 	}
 
+	/**
+	 * @param {(renderer: Renderer) => MaybePromise<void>} fn
+	 */
+	child_block(fn) {
+		this.#out.push(BLOCK_OPEN);
+		this.child(fn);
+		this.#out.push(BLOCK_CLOSE);
+	}
+
 	/**
 	 * Create a child renderer. The child renderer inherits the state from the parent,
 	 * but has its own content.
diff --git a/packages/svelte/tests/snapshot/samples/async-const/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-const/_expected/server/index.svelte.js
index a726b903bc..03bbc5ba88 100644
--- a/packages/svelte/tests/snapshot/samples/async-const/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-const/_expected/server/index.svelte.js
@@ -19,11 +19,7 @@ export default function Async_const($$renderer) {
 		]);
 
 		$$renderer.push(`<p>`);
-
-		$$renderer.async([promises[1]], ($$renderer) => {
-			$$renderer.push(() => $.escape(b));
-		});
-
+		$$renderer.async([promises[1]], ($$renderer) => $$renderer.push(() => $.escape(b)));
 		$$renderer.push(`</p>`);
 	} else {
 		$$renderer.push('<!--[!-->');
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 7249fd6e4f..b331875d04 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
@@ -2,7 +2,7 @@ import 'svelte/internal/flags/async';
 import * as $ from 'svelte/internal/server';
 
 export default function Async_each_fallback_hoisting($$renderer) {
-	$$renderer.async_block([], async ($$renderer) => {
+	$$renderer.child_block(async ($$renderer) => {
 		const each_array = $.ensure_array_like((await $.save(Promise.resolve([])))());
 
 		if (each_array.length !== 0) {
diff --git a/packages/svelte/tests/snapshot/samples/async-each-hoisting/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-each-hoisting/_expected/server/index.svelte.js
index 43fe9414eb..86948b4a3a 100644
--- a/packages/svelte/tests/snapshot/samples/async-each-hoisting/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-each-hoisting/_expected/server/index.svelte.js
@@ -8,7 +8,7 @@ export default function Async_each_hoisting($$renderer) {
 
 	$$renderer.push(`<!--[-->`);
 
-	$$renderer.async_block([], async ($$renderer) => {
+	$$renderer.child_block(async ($$renderer) => {
 		const each_array = $.ensure_array_like((await $.save(Promise.resolve([first, second, third])))());
 
 		for (let $$index = 0, $$length = each_array.length; $$index < $$length; $$index++) {
diff --git a/packages/svelte/tests/snapshot/samples/async-if-alternate-hoisting/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-if-alternate-hoisting/_expected/server/index.svelte.js
index 1e7330429a..c69c038973 100644
--- a/packages/svelte/tests/snapshot/samples/async-if-alternate-hoisting/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-if-alternate-hoisting/_expected/server/index.svelte.js
@@ -2,7 +2,7 @@ import 'svelte/internal/flags/async';
 import * as $ from 'svelte/internal/server';
 
 export default function Async_if_alternate_hoisting($$renderer) {
-	$$renderer.async_block([], async ($$renderer) => {
+	$$renderer.child_block(async ($$renderer) => {
 		if ((await $.save(Promise.resolve(false)))()) {
 			$$renderer.push('<!--[-->');
 			$$renderer.push(async () => $.escape(await Promise.reject('no no no')));
diff --git a/packages/svelte/tests/snapshot/samples/async-if-hoisting/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-if-hoisting/_expected/server/index.svelte.js
index 1ca24cf81a..1355ba34f0 100644
--- a/packages/svelte/tests/snapshot/samples/async-if-hoisting/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-if-hoisting/_expected/server/index.svelte.js
@@ -2,7 +2,7 @@ import 'svelte/internal/flags/async';
 import * as $ from 'svelte/internal/server';
 
 export default function Async_if_hoisting($$renderer) {
-	$$renderer.async_block([], async ($$renderer) => {
+	$$renderer.child_block(async ($$renderer) => {
 		if ((await $.save(Promise.resolve(true)))()) {
 			$$renderer.push('<!--[-->');
 			$$renderer.push(async () => $.escape(await Promise.resolve('yes yes yes')));
diff --git a/packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/_expected/server/index.svelte.js
index eb99a2fe1d..cff5f2d569 100644
--- a/packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-top-level-inspect-server/_expected/server/index.svelte.js
@@ -6,10 +6,6 @@ export default function Async_top_level_inspect_server($$renderer) {
 	var $$promises = $$renderer.run([async () => data = await Promise.resolve(42),,]);
 
 	$$renderer.push(`<p>`);
-
-	$$renderer.async([$$promises[1]], ($$renderer) => {
-		$$renderer.push(() => $.escape(data));
-	});
-
+	$$renderer.async([$$promises[1]], ($$renderer) => $$renderer.push(() => $.escape(data)));
 	$$renderer.push(`</p>`);
 }
\ No newline at end of file

From bc449758695ec0b5cd34b4cdfa7aaf1ccbc5105b Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 6 Feb 2026 04:19:14 -0500
Subject: [PATCH 122/142] fix: properly hydrate already-resolved async blocks
 (alternative) (#17641)

This is basically #17611, minus #17640, plus #17639. We need to add the $.next() call after render tags as well as components; rather than duplicating the logic, we can use is_standalone to determine when this is necessary (since this is what prevents $.append(...) from being used).

Fixes #17261
Fixes #17608
---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/poor-students-nail.md              |  5 ++++
 .../3-transform/client/transform-client.js    |  1 +
 .../phases/3-transform/client/types.d.ts      |  3 +++
 .../3-transform/client/visitors/Fragment.js   |  5 +++-
 .../3-transform/client/visitors/RenderTag.js  |  4 ++++
 .../client/visitors/shared/component.js       | 24 ++++++++++++-------
 .../server/visitors/shared/component.js       |  8 ++++++-
 .../Inner.svelte                              |  4 ++++
 .../Outer.svelte                              |  4 ++++
 .../Trigger.svelte                            |  7 ++++++
 .../_config.js                                | 10 ++++++++
 .../main.svelte                               | 16 +++++++++++++
 .../Component.svelte                          |  5 ++++
 .../async-each-item-duplication/_config.js    | 14 +++++++++++
 .../async-each-item-duplication/main.svelte   | 10 ++++++++
 15 files changed, 109 insertions(+), 11 deletions(-)
 create mode 100644 .changeset/poor-students-nail.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/Inner.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/Outer.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/Trigger.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-each-item-duplication/Component.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-each-item-duplication/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-each-item-duplication/main.svelte

diff --git a/.changeset/poor-students-nail.md b/.changeset/poor-students-nail.md
new file mode 100644
index 0000000000..cee650c002
--- /dev/null
+++ b/.changeset/poor-students-nail.md
@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+fix: properly hydrate already-resolved async blocks
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 d5ce3caaa9..b50a73b8b6 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
@@ -166,6 +166,7 @@ export function client_component(analysis, options) {
 		in_constructor: false,
 		instance_level_snippets: [],
 		module_level_snippets: [],
+		is_standalone: false,
 
 		// these are set inside the `Fragment` visitor, and cannot be used until then
 		init: /** @type {any} */ (null),
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 4438ec015b..287bf24ac6 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
@@ -83,6 +83,9 @@ export interface ComponentClientTransformState extends ClientTransformState {
 	readonly instance_level_snippets: VariableDeclaration[];
 	/** Snippets hoisted to the module */
 	readonly module_level_snippets: VariableDeclaration[];
+
+	/** True if the current node is a) a component or render tag and b) the sole child of a block  */
+	readonly is_standalone: boolean;
 }
 
 export type Context = import('zimmerframe').Context<AST.SvelteNode, ClientTransformState>;
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 f463111c4d..00b0cfaa2e 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
@@ -122,7 +122,10 @@ export function Fragment(node, context) {
 			close = b.stmt(b.call('$.append', b.id('$$anchor'), id));
 		} else if (is_standalone) {
 			// no need to create a template, we can just use the existing block's anchor
-			process_children(trimmed, () => b.id('$$anchor'), false, { ...context, state });
+			process_children(trimmed, () => b.id('$$anchor'), false, {
+				...context,
+				state: { ...state, is_standalone }
+			});
 		} else {
 			/** @type {(is_text: boolean) => Expression} */
 			const expression = (is_text) => b.call('$.first_child', id, is_text && b.true);
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RenderTag.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RenderTag.js
index d14336bb7e..5d39cf2216 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/RenderTag.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/RenderTag.js
@@ -85,6 +85,10 @@ export function RenderTag(node, context) {
 				)
 			)
 		);
+
+		if (context.state.is_standalone) {
+			context.state.init.push(b.stmt(b.call('$.next')));
+		}
 	} else {
 		context.state.init.push(statements.length === 1 ? statements[0] : b.block(statements));
 	}
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/component.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/component.js
index bb72794af8..1d6d3413bf 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/component.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/component.js
@@ -461,7 +461,7 @@ export function build_component(node, component_name, loc, context) {
 		memoizer.check_blockers(node.metadata.expression);
 	}
 
-	const statements = [...snippet_declarations, ...memoizer.deriveds(context.state.analysis.runes)];
+	let statements = [...snippet_declarations, ...memoizer.deriveds(context.state.analysis.runes)];
 
 	if (is_component_dynamic) {
 		const prev = fn;
@@ -515,15 +515,21 @@ export function build_component(node, component_name, loc, context) {
 	const blockers = memoizer.blockers();
 
 	if (async_values || blockers) {
-		return b.stmt(
-			b.call(
-				'$.async',
-				anchor,
-				blockers,
-				async_values,
-				b.arrow([b.id('$$anchor'), ...memoizer.async_ids()], b.block(statements))
+		statements = [
+			b.stmt(
+				b.call(
+					'$.async',
+					anchor,
+					blockers,
+					async_values,
+					b.arrow([b.id('$$anchor'), ...memoizer.async_ids()], b.block(statements))
+				)
 			)
-		);
+		];
+
+		if (context.state.is_standalone) {
+			statements.push(b.stmt(b.call('$.next')));
+		}
 	}
 
 	return statements.length > 1 ? b.block(statements) : statements[0];
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/component.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/component.js
index fe49a67b28..6a2c6eb0be 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/component.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/component.js
@@ -101,10 +101,16 @@ export function build_inline_component(node, expression, context) {
 			}
 
 			push_prop(b.prop('init', b.key(attribute.name), value));
-		} else if (attribute.type === 'BindDirective' && attribute.name !== 'this') {
+		} else if (attribute.type === 'BindDirective') {
 			// Bindings are a bit special: we don't want to add them to (async) deriveds but we need to check if they have blockers
 			optimiser.check_blockers(attribute.metadata.expression);
 
+			if (attribute.name === 'this') {
+				// bind:this is client-only, but we still need to check for blockers to ensure
+				// the server generates matching hydration markers if the client wraps in $.async
+				continue;
+			}
+
 			if (attribute.expression.type === 'SequenceExpression') {
 				const [get, set] = /** @type {SequenceExpression} */ (context.visit(attribute.expression))
 					.expressions;
diff --git a/packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/Inner.svelte b/packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/Inner.svelte
new file mode 100644
index 0000000000..99f885189b
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/Inner.svelte
@@ -0,0 +1,4 @@
+<script>
+  let { children } = $props()
+</script>
+<div>{@render children?.()}</div>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/Outer.svelte b/packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/Outer.svelte
new file mode 100644
index 0000000000..99f885189b
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/Outer.svelte
@@ -0,0 +1,4 @@
+<script>
+  let { children } = $props()
+</script>
+<div>{@render children?.()}</div>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/Trigger.svelte b/packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/Trigger.svelte
new file mode 100644
index 0000000000..fc434d748e
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/Trigger.svelte
@@ -0,0 +1,7 @@
+<script lang='ts'>
+  import type { Attachment } from 'svelte/attachments'
+
+  export function action(): Attachment<HTMLElement> {
+    return ()=>{}
+  }
+</script>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/_config.js b/packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/_config.js
new file mode 100644
index 0000000000..d77ba45ae4
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/_config.js
@@ -0,0 +1,10 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['hydrate'],
+	async test({ assert, target }) {
+		await tick();
+		assert.htmlEqual(target.innerHTML, '<div><div>foo</div></div>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/main.svelte
new file mode 100644
index 0000000000..6cfc73ca25
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-attach-hydration-mismatch/main.svelte
@@ -0,0 +1,16 @@
+<script>
+  import Outer from './Outer.svelte'
+  import Inner from './Inner.svelte'
+  import Trigger from './Trigger.svelte'
+
+  const data = $derived(await Promise.resolve(['a', 'b']))
+  let trigger = $state()
+</script>
+
+<Outer>
+  <Inner {@attach trigger?.action}>
+    foo
+  </Inner>
+</Outer>
+
+<Trigger bind:this={trigger} />
diff --git a/packages/svelte/tests/runtime-runes/samples/async-each-item-duplication/Component.svelte b/packages/svelte/tests/runtime-runes/samples/async-each-item-duplication/Component.svelte
new file mode 100644
index 0000000000..9f4e638629
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-each-item-duplication/Component.svelte
@@ -0,0 +1,5 @@
+<script>
+	let { message, another } = $props()
+</script>
+
+<p>{message}</p>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-each-item-duplication/_config.js b/packages/svelte/tests/runtime-runes/samples/async-each-item-duplication/_config.js
new file mode 100644
index 0000000000..2e20f83f7f
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-each-item-duplication/_config.js
@@ -0,0 +1,14 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['hydrate'],
+
+	ssrHtml: `<p>item 1</p><p>item 2</p><p>item 3</p>`,
+	html: `<p>item 1</p><p>item 2</p><p>item 3</p>`,
+
+	async test({ assert, target }) {
+		await tick();
+		assert.htmlEqual(target.innerHTML, '<p>item 1</p><p>item 2</p><p>item 3</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-each-item-duplication/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-each-item-duplication/main.svelte
new file mode 100644
index 0000000000..ae54b63414
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-each-item-duplication/main.svelte
@@ -0,0 +1,10 @@
+<script>
+	import Component from './Component.svelte'
+
+	const messages = await Promise.resolve(["item 1", "item 2", "item 3"])
+	const another = { test: 'test' }
+</script>
+
+{#each messages as message}
+	<Component {message} {another} />
+{/each}

From 6e5f2b157a02df4dd1f4e2ad3275655bc52cd023 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 6 Feb 2026 10:54:15 -0500
Subject: [PATCH 123/142] fix: exit resolved async blocks on correct node when
 hydrating (#17640)

* fix: exit resolved async blocks on correct node when hydrating

* expand test + fix

* tweak, add note to self

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
---
 .changeset/tiny-owls-pay.md                    |  5 +++++
 .../src/internal/client/dom/blocks/async.js    | 15 ++++++++++++++-
 .../samples/async-if-hydration/Child.svelte    |  5 +++++
 .../samples/async-if-hydration/_config.js      | 11 +++++++++++
 .../samples/async-if-hydration/main.svelte     | 18 ++++++++++++++++++
 5 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/tiny-owls-pay.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-if-hydration/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-if-hydration/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-if-hydration/main.svelte

diff --git a/.changeset/tiny-owls-pay.md b/.changeset/tiny-owls-pay.md
new file mode 100644
index 0000000000..ac25500258
--- /dev/null
+++ b/.changeset/tiny-owls-pay.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: exit resolved async blocks on correct node when hydrating
diff --git a/packages/svelte/src/internal/client/dom/blocks/async.js b/packages/svelte/src/internal/client/dom/blocks/async.js
index 0e3ab33dda..e8c9cf0643 100644
--- a/packages/svelte/src/internal/client/dom/blocks/async.js
+++ b/packages/svelte/src/internal/client/dom/blocks/async.js
@@ -20,13 +20,27 @@ import { get_boundary } from './boundary.js';
  */
 export function async(node, blockers = [], expressions = [], fn) {
 	var was_hydrating = hydrating;
+	var end = null;
 
 	if (was_hydrating) {
 		hydrate_next();
+		end = skip_nodes(false);
 	}
 
 	if (expressions.length === 0 && blockers.every((b) => b.settled)) {
 		fn(node);
+
+		// This is necessary because it is not guaranteed that the render function will
+		// advance the hydration node to $.async's end marker: it may stop at an inner
+		// block's end marker (in case of an inner if block for example), but it also may
+		// stop at the correct $.async end marker (in case of component child) - hence
+		// we can't just use hydrate_next()
+		// TODO this feels indicative of a bug elsewhere; ideally we wouldn't need
+		// to double-traverse in the already-resolved case
+		if (was_hydrating) {
+			set_hydrate_node(end);
+		}
+
 		return;
 	}
 
@@ -39,7 +53,6 @@ export function async(node, blockers = [], expressions = [], fn) {
 
 	if (was_hydrating) {
 		var previous_hydrate_node = hydrate_node;
-		var end = skip_nodes(false);
 		set_hydrate_node(end);
 	}
 
diff --git a/packages/svelte/tests/runtime-runes/samples/async-if-hydration/Child.svelte b/packages/svelte/tests/runtime-runes/samples/async-if-hydration/Child.svelte
new file mode 100644
index 0000000000..02ef294d99
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-if-hydration/Child.svelte
@@ -0,0 +1,5 @@
+<script>
+    let { b } = $props();
+</script>
+
+{b}
diff --git a/packages/svelte/tests/runtime-runes/samples/async-if-hydration/_config.js b/packages/svelte/tests/runtime-runes/samples/async-if-hydration/_config.js
new file mode 100644
index 0000000000..8132e9c522
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-if-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, `<div><p>hello</p></div> <div>true</div>`);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-if-hydration/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-if-hydration/main.svelte
new file mode 100644
index 0000000000..3b08d41640
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-if-hydration/main.svelte
@@ -0,0 +1,18 @@
+<script lang="ts">
+	import Child from "./Child.svelte";
+
+	await 1;
+	let b = true;
+	let a = true;
+</script>
+
+{#if a}
+	<div>
+		{#if b}
+			<p>hello</p>
+		{/if}
+	</div>
+	<div>
+		<Child {b} />
+	</div>
+{/if}

From 989492f0572cb6dd4beaf621dfbba0bcd409913c Mon Sep 17 00:00:00 2001
From: Artyom Alekseevich <47069814+FrankFMY@users.noreply.github.com>
Date: Fri, 6 Feb 2026 17:01:41 +0100
Subject: [PATCH 124/142] fix: use "set up" (verb) instead of "setup" (noun) in
 comments (#17632)

"Setup" is a noun/adjective, while "set up" is the verb form.
---
 documentation/docs/07-misc/02-testing.md | 2 +-
 packages/svelte/tests/signals/test.ts    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/documentation/docs/07-misc/02-testing.md b/documentation/docs/07-misc/02-testing.md
index 85db7fc01f..c1bc69c1c2 100644
--- a/documentation/docs/07-misc/02-testing.md
+++ b/documentation/docs/07-misc/02-testing.md
@@ -181,7 +181,7 @@ export default defineConfig({
 		/* ... */
 	],
 	test: {
-		// If you are testing components client-side, you need to setup a DOM environment.
+		// If you are testing components client-side, you need to set up a DOM environment.
 		// If not all your files should have this environment, you can use a
 		// `// @vitest-environment jsdom` comment at the top of the test files instead.
 		environment: 'jsdom'
diff --git a/packages/svelte/tests/signals/test.ts b/packages/svelte/tests/signals/test.ts
index 23c4bb42f9..5486ccdb45 100644
--- a/packages/svelte/tests/signals/test.ts
+++ b/packages/svelte/tests/signals/test.ts
@@ -21,7 +21,7 @@ import { disable_async_mode_flag, enable_async_mode_flag } from '../../src/inter
 
 /**
  * @param runes runes mode
- * @param fn A function that returns a function because we first need to setup all the signals
+ * @param fn A function that returns a function because we first need to set up all the signals
  * 			 and then execute the test in order to simulate a real component
  */
 function run_test(runes: boolean, fn: (runes: boolean) => () => void) {

From 01db7b8c2a0dbc7eb1fb8f1eff116f2b5b5b3ba9 Mon Sep 17 00:00:00 2001
From: Artyom Alekseevich <47069814+FrankFMY@users.noreply.github.com>
Date: Fri, 6 Feb 2026 17:03:14 +0100
Subject: [PATCH 125/142] fix: update migration guide to reflect current
 passive events (#17631)

Remove `onwheel` and `onmousewheel` from the list of passive events
in the v5 migration guide. Since #13322, only `ontouchstart` and
`ontouchmove` are passive by default, matching the basic-markup docs.

Closes #17430
---
 documentation/docs/07-misc/07-v5-migration-guide.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/documentation/docs/07-misc/07-v5-migration-guide.md b/documentation/docs/07-misc/07-v5-migration-guide.md
index 40cbc3bd9e..5a80734b7a 100644
--- a/documentation/docs/07-misc/07-v5-migration-guide.md
+++ b/documentation/docs/07-misc/07-v5-migration-guide.md
@@ -778,9 +778,9 @@ In Svelte 4, doing the following triggered reactivity:
 
 This is because the Svelte compiler treated the assignment to `foo.value` as an instruction to update anything that referenced `foo`. In Svelte 5, reactivity is determined at runtime rather than compile time, so you should define `value` as a reactive `$state` field on the `Foo` class. Wrapping `new Foo()` with `$state(...)` will have no effect — only vanilla objects and arrays are made deeply reactive.
 
-### Touch and wheel events are passive
+### Touch events are passive
 
-When using `onwheel`, `onmousewheel`, `ontouchstart` and `ontouchmove` event attributes, the handlers are [passive](https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/addEventListener#using_passive_listeners) to align with browser defaults. This greatly improves responsiveness by allowing the browser to scroll the document immediately, rather than waiting to see if the event handler calls `event.preventDefault()`.
+When using `ontouchstart` and `ontouchmove` event attributes, the handlers are [passive](https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/addEventListener#using_passive_listeners) to align with browser defaults. This greatly improves responsiveness by allowing the browser to scroll the document immediately, rather than waiting to see if the event handler calls `event.preventDefault()`.
 
 In the very rare cases that you need to prevent these event defaults, you should use [`on`](/docs/svelte/svelte-events#on) instead (for example inside an action).
 

From 0c715afdab2c3077b32793a41a7ddccb3be65c64 Mon Sep 17 00:00:00 2001
From: Artyom Alekseevich <47069814+FrankFMY@users.noreply.github.com>
Date: Fri, 6 Feb 2026 17:03:58 +0100
Subject: [PATCH 126/142] fix: correct spelling errors in test files (#17630)

Fix "wich" -> "which", "aswell" -> "as well" in CSS global-block test,
and "occurence" -> "occurrence" in sourcemaps test type definition.
---
 packages/svelte/tests/css/samples/global-block/expected.css | 4 ++--
 packages/svelte/tests/css/samples/global-block/input.svelte | 4 ++--
 packages/svelte/tests/sourcemaps/test.ts                    | 4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/packages/svelte/tests/css/samples/global-block/expected.css b/packages/svelte/tests/css/samples/global-block/expected.css
index be1838fd98..ef68280093 100644
--- a/packages/svelte/tests/css/samples/global-block/expected.css
+++ b/packages/svelte/tests/css/samples/global-block/expected.css
@@ -39,7 +39,7 @@
 		/*}*/
 	}
 
-	/* ...wich is equivalent to `div :global { &.x { ...} }` ... */
+	/* ...which is equivalent to `div :global { &.x { ...} }` ... */
 	div.svelte-xyz {
 		&.x {
 			color: green;
@@ -51,7 +51,7 @@
 		color: green;
 	}
 
-	/* ...and therefore `div { :global.x { ... }` aswell */
+	/* ...and therefore `div { :global.x { ... }` as well */
 	div.svelte-xyz {
 		&.x {
 			color: green;
diff --git a/packages/svelte/tests/css/samples/global-block/input.svelte b/packages/svelte/tests/css/samples/global-block/input.svelte
index 86d438031a..1a9993bfe0 100644
--- a/packages/svelte/tests/css/samples/global-block/input.svelte
+++ b/packages/svelte/tests/css/samples/global-block/input.svelte
@@ -41,7 +41,7 @@
 		}
 	}
 
-	/* ...wich is equivalent to `div :global { &.x { ...} }` ... */
+	/* ...which is equivalent to `div :global { &.x { ...} }` ... */
 	div :global {
 		&.x {
 			color: green;
@@ -53,7 +53,7 @@
 		color: green;
 	}
 
-	/* ...and therefore `div { :global.x { ... }` aswell */
+	/* ...and therefore `div { :global.x { ... }` as well */
 	div {
 		:global.x {
 			color: green;
diff --git a/packages/svelte/tests/sourcemaps/test.ts b/packages/svelte/tests/sourcemaps/test.ts
index 0ac0e6f905..6749483079 100644
--- a/packages/svelte/tests/sourcemaps/test.ts
+++ b/packages/svelte/tests/sourcemaps/test.ts
@@ -8,9 +8,9 @@ import { decode } from '@jridgewell/sourcemap-codec';
 type SourceMapEntry =
 	| string
 	| {
-			/** If not the first occurence, but the nth should be found */
+			/** If not the first occurrence, but the nth should be found */
 			idxOriginal?: number;
-			/** If not the first occurence, but the nth should be found */
+			/** If not the first occurrence, but the nth should be found */
 			idxGenerated?: number;
 			/** The original string to find */
 			str: string;

From 4453e4895d407df6895f481257b675a43ed702c6 Mon Sep 17 00:00:00 2001
From: Artyom Alekseevich <47069814+FrankFMY@users.noreply.github.com>
Date: Fri, 6 Feb 2026 17:04:42 +0100
Subject: [PATCH 127/142] fix: fix spelling errors in media-query and test file
 (#17628)

- media-query.js: parentehesis -> parenthesis
- error-boundary-12/main.svelte: occured -> occurred
---
 packages/svelte/src/reactivity/media-query.js                   | 2 +-
 .../tests/runtime-runes/samples/error-boundary-12/main.svelte   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/svelte/src/reactivity/media-query.js b/packages/svelte/src/reactivity/media-query.js
index d286709719..6d1d084298 100644
--- a/packages/svelte/src/reactivity/media-query.js
+++ b/packages/svelte/src/reactivity/media-query.js
@@ -7,7 +7,7 @@ const parenthesis_regex = /\(.+\)/;
 //
 // eg: new MediaQuery('screen')
 //
-// however because of the auto-parenthesis logic in the constructor since there's no parentehesis
+// however because of the auto-parenthesis logic in the constructor since there's no parenthesis
 // in the media query they'll be surrounded by parenthesis
 //
 // however we can check if the media query is only composed of these keywords
diff --git a/packages/svelte/tests/runtime-runes/samples/error-boundary-12/main.svelte b/packages/svelte/tests/runtime-runes/samples/error-boundary-12/main.svelte
index d9dee1e2b0..748acab91e 100644
--- a/packages/svelte/tests/runtime-runes/samples/error-boundary-12/main.svelte
+++ b/packages/svelte/tests/runtime-runes/samples/error-boundary-12/main.svelte
@@ -15,6 +15,6 @@
 	{d}
 
 	{#snippet failed()}
-		<p>Error occured</p>
+		<p>Error occurred</p>
 	{/snippet}
 </svelte:boundary>

From f71a6813b7bf9c53b1dce0b5f3a1232f55b1f26a Mon Sep 17 00:00:00 2001
From: Artyom Alekseevich <47069814+FrankFMY@users.noreply.github.com>
Date: Fri, 6 Feb 2026 17:13:54 +0100
Subject: [PATCH 128/142] fix: treat menu element like ul/ol for a11y role
 checks (#17638)

* treat menu element like ul/ol for a11y role checks

The <menu> element has the same implicit role (list) as <ul> and <ol>,
so it should receive the same treatment in a11y checks:

- Allow <menu role="list"> without redundant role warning (CSS
  list-style:none can remove semantics, role restores them)
- Allow <menu> with interactive roles like menu, menubar, radiogroup,
  tablist, tree, treegrid (same exceptions as ul/ol)

Fixes #8529

* changeset

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/fix-menu-element-a11y-roles.md            |  5 +++++
 .../2-analyze/visitors/shared/a11y/constants.js      |  1 +
 .../phases/2-analyze/visitors/shared/a11y/index.js   |  2 +-
 .../input.svelte                                     |  7 +++++++
 .../samples/a11y-no-redundant-roles/input.svelte     |  4 ++--
 .../samples/a11y-no-redundant-roles/warnings.json    | 12 ------------
 6 files changed, 16 insertions(+), 15 deletions(-)
 create mode 100644 .changeset/fix-menu-element-a11y-roles.md

diff --git a/.changeset/fix-menu-element-a11y-roles.md b/.changeset/fix-menu-element-a11y-roles.md
new file mode 100644
index 0000000000..75cfe8d310
--- /dev/null
+++ b/.changeset/fix-menu-element-a11y-roles.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: treat `<menu>` like `<ul>`/`<ol>` for a11y role checks
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 684ea92094..49099c2cb1 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
@@ -174,6 +174,7 @@ export const input_type_to_implicit_role = new Map([
 export const a11y_non_interactive_element_to_interactive_role_exceptions = {
 	ul: ['listbox', 'menu', 'menubar', 'radiogroup', 'tablist', 'tree', 'treegrid'],
 	ol: ['listbox', 'menu', 'menubar', 'radiogroup', 'tablist', 'tree', 'treegrid'],
+	menu: ['listbox', 'menu', 'menubar', 'radiogroup', 'tablist', 'tree', 'treegrid'],
 	li: ['menuitem', 'option', 'row', 'tab', 'treeitem'],
 	table: ['grid'],
 	td: ['gridcell'],
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 f5f4982ed2..45de8b10a1 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
@@ -167,7 +167,7 @@ export function check_element(node, context) {
 					if (
 						current_role === get_implicit_role(node.name, attribute_map) &&
 						// <ul role="list"> is ok because CSS list-style:none removes the semantics and this is a way to bring them back
-						!['ul', 'ol', 'li'].includes(node.name) &&
+						!['ul', 'ol', 'li', 'menu'].includes(node.name) &&
 						// <a role="link" /> is ok because without href the a tag doesn't have a role of link
 						!(node.name === 'a' && !attribute_map.has('href'))
 					) {
diff --git a/packages/svelte/tests/validator/samples/a11y-no-noninteractive-element-to-interactive-role/input.svelte b/packages/svelte/tests/validator/samples/a11y-no-noninteractive-element-to-interactive-role/input.svelte
index e5db8719b0..edfa3eeada 100644
--- a/packages/svelte/tests/validator/samples/a11y-no-noninteractive-element-to-interactive-role/input.svelte
+++ b/packages/svelte/tests/validator/samples/a11y-no-noninteractive-element-to-interactive-role/input.svelte
@@ -69,6 +69,13 @@
 <li role="menuitem"></li>
 <li role="row"></li>
 <li role="treeitem" aria-selected={false}></li>
+<!-- menu -->
+<menu role="menu"></menu>
+<menu role="menubar"></menu>
+<menu role="radiogroup"></menu>
+<menu role="tablist"></menu>
+<menu role="tree"></menu>
+<menu role="treegrid"></menu>
 
 <!-- VALID: elements assigned an interactive role. -->
 <div role="button"></div>
diff --git a/packages/svelte/tests/validator/samples/a11y-no-redundant-roles/input.svelte b/packages/svelte/tests/validator/samples/a11y-no-redundant-roles/input.svelte
index 2ccd765aa2..9e06ebe420 100644
--- a/packages/svelte/tests/validator/samples/a11y-no-redundant-roles/input.svelte
+++ b/packages/svelte/tests/validator/samples/a11y-no-redundant-roles/input.svelte
@@ -22,7 +22,7 @@
 <!-- <li role="listitem" /> allowed since CSS list-style none removes semantic meaning and role brings it back -->
 <link role="link" />
 <main role="main"></main>
-<menu role="list"></menu>
+<!-- <menu role="list" /> allowed, same as ul/ol above -->
 <nav role="navigation"></nav>
 <!-- <ol role="list" /> allowed, see comment above -->
 <optgroup role="group"></optgroup>
@@ -44,5 +44,5 @@
 <footer role="contentinfo"></footer>
 
 <!-- Allowed -->
-<!-- svelte-ignore a11y_no_noninteractive_element_to_interactive_role -->
+<!-- menu has same interactive role exceptions as ul/ol -->
 <menu role="menu"></menu>
diff --git a/packages/svelte/tests/validator/samples/a11y-no-redundant-roles/warnings.json b/packages/svelte/tests/validator/samples/a11y-no-redundant-roles/warnings.json
index 861f000aef..e041037d71 100644
--- a/packages/svelte/tests/validator/samples/a11y-no-redundant-roles/warnings.json
+++ b/packages/svelte/tests/validator/samples/a11y-no-redundant-roles/warnings.json
@@ -275,18 +275,6 @@
 			"line": 24
 		}
 	},
-	{
-		"code": "a11y_no_redundant_roles",
-		"end": {
-			"column": 17,
-			"line": 25
-		},
-		"message": "Redundant role 'list'",
-		"start": {
-			"column": 6,
-			"line": 25
-		}
-	},
 	{
 		"code": "a11y_no_redundant_roles",
 		"end": {

From bd7b8aa10807be8884f5e7224340f8d980d971ec Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 6 Feb 2026 11:37:25 -0500
Subject: [PATCH 129/142] chore: fix broken css test (#17644)

---
 packages/svelte/tests/css/samples/global-block/_config.js | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/packages/svelte/tests/css/samples/global-block/_config.js b/packages/svelte/tests/css/samples/global-block/_config.js
index 18a56e9a97..84b4989f76 100644
--- a/packages/svelte/tests/css/samples/global-block/_config.js
+++ b/packages/svelte/tests/css/samples/global-block/_config.js
@@ -9,12 +9,12 @@ export default test({
 			start: {
 				line: 73,
 				column: 1,
-				character: 964
+				character: 966
 			},
 			end: {
 				line: 73,
 				column: 16,
-				character: 979
+				character: 981
 			}
 		},
 		{
@@ -23,12 +23,12 @@ export default test({
 			start: {
 				line: 104,
 				column: 29,
-				character: 1270
+				character: 1272
 			},
 			end: {
 				line: 104,
 				column: 43,
-				character: 1284
+				character: 1286
 			}
 		}
 	]

From 57cb393796841538c1b38ef99dd2be48815604a5 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 6 Feb 2026 11:57:49 -0500
Subject: [PATCH 130/142] fix: allow NaN in key blocks (#17642)

* fix: allow NaN in key blocks

* lol whoops

* Update packages/svelte/src/internal/client/dom/blocks/key.js

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/clear-olives-share.md                |  5 +++++
 .../src/internal/client/dom/blocks/key.js       |  7 +++++++
 .../runtime-runes/samples/key-nan/_config.js    | 17 +++++++++++++++++
 .../runtime-runes/samples/key-nan/main.svelte   | 10 ++++++++++
 4 files changed, 39 insertions(+)
 create mode 100644 .changeset/clear-olives-share.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/key-nan/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/key-nan/main.svelte

diff --git a/.changeset/clear-olives-share.md b/.changeset/clear-olives-share.md
new file mode 100644
index 0000000000..975b2b21b6
--- /dev/null
+++ b/.changeset/clear-olives-share.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: allow `{#key NaN}`
diff --git a/packages/svelte/src/internal/client/dom/blocks/key.js b/packages/svelte/src/internal/client/dom/blocks/key.js
index 849b1c2447..dd40d8a1b8 100644
--- a/packages/svelte/src/internal/client/dom/blocks/key.js
+++ b/packages/svelte/src/internal/client/dom/blocks/key.js
@@ -4,6 +4,8 @@ import { block } from '../../reactivity/effects.js';
 import { hydrate_next, hydrating } from '../hydration.js';
 import { BranchManager } from './branches.js';
 
+const NAN = Symbol('NaN');
+
 /**
  * @template V
  * @param {TemplateNode} node
@@ -23,6 +25,11 @@ export function key(node, get_key, render_fn) {
 	block(() => {
 		var key = get_key();
 
+		// NaN !== NaN, hence we do this workaround to not trigger remounts unnecessarily
+		if (key !== key) {
+			key = /** @type {any} */ (NAN);
+		}
+
 		// key blocks in Svelte <5 had stupid semantics
 		if (legacy && key !== null && typeof key === 'object') {
 			key = /** @type {V} */ ({});
diff --git a/packages/svelte/tests/runtime-runes/samples/key-nan/_config.js b/packages/svelte/tests/runtime-runes/samples/key-nan/_config.js
new file mode 100644
index 0000000000..bd0dd06761
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/key-nan/_config.js
@@ -0,0 +1,17 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	html: '<button>update</button><p>it rendered</p>',
+
+	test({ assert, target, logs }) {
+		assert.deepEqual(logs, ['rendering']);
+
+		const btn = target.querySelector('button');
+		flushSync(() => btn?.click());
+
+		// should not re-render
+		assert.deepEqual(logs, ['rendering']);
+		assert.htmlEqual(target.innerHTML, '<button>update</button><p>it rendered</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/key-nan/main.svelte b/packages/svelte/tests/runtime-runes/samples/key-nan/main.svelte
new file mode 100644
index 0000000000..24f7f2d179
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/key-nan/main.svelte
@@ -0,0 +1,10 @@
+<script>
+	let x = $state(NaN);
+</script>
+
+<button onclick={() => x = NaN}>update</button>
+
+{#key x}
+	{console.log('rendering')}
+	<p>it rendered</p>
+{/key}

From 863c9d6875470ad7699614fe278c0d99903d30f8 Mon Sep 17 00:00:00 2001
From: Andrew Aquino <dawneraq@gmail.com>
Date: Fri, 6 Feb 2026 10:27:13 -0800
Subject: [PATCH 131/142] chore: wrap JSDoc URLs in @see and @link tags
 (#17617)

* docs: wrap JSDoc URLs in @see and @link tags

* fix: move curly brace to end of URL

* chore: add changeset

* add link text

* regenerate

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/loud-bottles-own.md                |  5 ++++
 packages/svelte/src/ambient.d.ts              | 28 +++++++++----------
 .../src/compiler/phases/1-parse/read/style.js |  2 +-
 .../client/dom/elements/bindings/size.js      |  5 ++--
 .../samples/transition-component/_config.js   |  2 +-
 packages/svelte/types/index.d.ts              | 28 +++++++++----------
 6 files changed, 37 insertions(+), 33 deletions(-)
 create mode 100644 .changeset/loud-bottles-own.md

diff --git a/.changeset/loud-bottles-own.md b/.changeset/loud-bottles-own.md
new file mode 100644
index 0000000000..493dc6c47f
--- /dev/null
+++ b/.changeset/loud-bottles-own.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+chore: wrap JSDoc URLs in `@see` and `@link` tags
diff --git a/packages/svelte/src/ambient.d.ts b/packages/svelte/src/ambient.d.ts
index ec5b799470..159a568477 100644
--- a/packages/svelte/src/ambient.d.ts
+++ b/packages/svelte/src/ambient.d.ts
@@ -16,7 +16,7 @@ declare module '*.svelte' {
  * let count = $state(0);
  * ```
  *
- * https://svelte.dev/docs/svelte/$state
+ * @see {@link https://svelte.dev/docs/svelte/$state Documentation}
  *
  * @param initial The initial value
  */
@@ -126,7 +126,7 @@ declare namespace $state {
 	 * </button>
 	 * ```
 	 *
-	 * https://svelte.dev/docs/svelte/$state#$state.raw
+	 * @see {@link https://svelte.dev/docs/svelte/$state#$state.raw Documentation}
 	 *
 	 * @param initial The initial value
 	 */
@@ -147,7 +147,7 @@ declare namespace $state {
 	 * </script>
 	 * ```
 	 *
-	 * https://svelte.dev/docs/svelte/$state#$state.snapshot
+	 * @see {@link https://svelte.dev/docs/svelte/$state#$state.snapshot Documentation}
 	 *
 	 * @param state The value to snapshot
 	 */
@@ -187,7 +187,7 @@ declare namespace $state {
  * let double = $derived(count * 2);
  * ```
  *
- * https://svelte.dev/docs/svelte/$derived
+ * @see {@link https://svelte.dev/docs/svelte/$derived Documentation}
  *
  * @param expression The derived state expression
  */
@@ -209,7 +209,7 @@ declare namespace $derived {
 	 * });
 	 * ```
 	 *
-	 * https://svelte.dev/docs/svelte/$derived#$derived.by
+	 * @see {@link https://svelte.dev/docs/svelte/$derived#$derived.by Documentation}
 	 */
 	export function by<T>(fn: () => T): T;
 
@@ -251,7 +251,7 @@ declare namespace $derived {
  *
  * Does not run during server-side rendering.
  *
- * https://svelte.dev/docs/svelte/$effect
+ * @see {@link https://svelte.dev/docs/svelte/$effect Documentation}
  * @param fn The function to execute
  */
 declare function $effect(fn: () => void | (() => void)): void;
@@ -270,7 +270,7 @@ declare namespace $effect {
 	 *
 	 * Does not run during server-side rendering.
 	 *
-	 * https://svelte.dev/docs/svelte/$effect#$effect.pre
+	 * @see {@link https://svelte.dev/docs/svelte/$effect#$effect.pre Documentation}
 	 * @param fn The function to execute
 	 */
 	export function pre(fn: () => void | (() => void)): void;
@@ -278,7 +278,7 @@ declare namespace $effect {
 	/**
 	 * Returns the number of promises that are pending in the current boundary, not including child boundaries.
 	 *
-	 * https://svelte.dev/docs/svelte/$effect#$effect.pending
+	 * @see {@link https://svelte.dev/docs/svelte/$effect#$effect.pending Documentation}
 	 */
 	export function pending(): number;
 
@@ -300,7 +300,7 @@ declare namespace $effect {
 	 *
 	 * This allows you to (for example) add things like subscriptions without causing memory leaks, by putting them in child effects.
 	 *
-	 * https://svelte.dev/docs/svelte/$effect#$effect.tracking
+	 * @see {@link https://svelte.dev/docs/svelte/$effect#$effect.tracking Documentation}
 	 */
 	export function tracking(): boolean;
 
@@ -328,7 +328,7 @@ declare namespace $effect {
 	 * <button onclick={() => cleanup()}>cleanup</button>
 	 * ```
 	 *
-	 * https://svelte.dev/docs/svelte/$effect#$effect.root
+	 * @see {@link https://svelte.dev/docs/svelte/$effect#$effect.root Documentation}
 	 */
 	export function root(fn: () => void | (() => void)): () => void;
 
@@ -364,7 +364,7 @@ declare namespace $effect {
  * let { optionalProp = 42, requiredProp, bindableProp = $bindable() }: { optionalProp?: number; requiredProps: string; bindableProp: boolean } = $props();
  * ```
  *
- * https://svelte.dev/docs/svelte/$props
+ * @see {@link https://svelte.dev/docs/svelte/$props Documentation}
  */
 declare function $props(): any;
 
@@ -410,7 +410,7 @@ declare namespace $props {
  * let { propName = $bindable() }: { propName: boolean } = $props();
  * ```
  *
- * https://svelte.dev/docs/svelte/$bindable
+ * @see {@link https://svelte.dev/docs/svelte/$bindable Documentation}
  */
 declare function $bindable<T>(fallback?: T): T;
 
@@ -456,7 +456,7 @@ declare namespace $bindable {
  * $inspect(x, y).with(() => { debugger; });
  * ```
  *
- * https://svelte.dev/docs/svelte/$inspect
+ * @see {@link https://svelte.dev/docs/svelte/$inspect Documentation}
  */
 declare function $inspect<T extends any[]>(
 	...values: T
@@ -522,7 +522,7 @@ declare namespace $inspect {
  *
  * Only available inside custom element components, and only on the client-side.
  *
- * https://svelte.dev/docs/svelte/$host
+ * @see {@link https://svelte.dev/docs/svelte/$host Documentation}
  */
 declare function $host<El extends HTMLElement = HTMLElement>(): El;
 
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 55647b2c94..4f2db349cd 100644
--- a/packages/svelte/src/compiler/phases/1-parse/read/style.js
+++ b/packages/svelte/src/compiler/phases/1-parse/read/style.js
@@ -568,7 +568,7 @@ function read_attribute_value(parser) {
 }
 
 /**
- * https://www.w3.org/TR/css-syntax-3/#ident-token-diagram
+ * @see {@link https://www.w3.org/TR/css-syntax-3/#ident-token-diagram CSS Syntax Module Level 3}
  * @param {Parser} parser
  */
 function read_identifier(parser) {
diff --git a/packages/svelte/src/internal/client/dom/elements/bindings/size.js b/packages/svelte/src/internal/client/dom/elements/bindings/size.js
index a76c70aab1..016ee5a547 100644
--- a/packages/svelte/src/internal/client/dom/elements/bindings/size.js
+++ b/packages/svelte/src/internal/client/dom/elements/bindings/size.js
@@ -2,9 +2,8 @@ import { effect, teardown } from '../../../reactivity/effects.js';
 import { untrack } from '../../../runtime.js';
 
 /**
- * Resize observer singleton.
- * One listener per element only!
- * https://groups.google.com/a/chromium.org/g/blink-dev/c/z6ienONUb5A/m/F5-VcUZtBAAJ
+ * We create one listener for all elements
+ * @see {@link https://groups.google.com/a/chromium.org/g/blink-dev/c/z6ienONUb5A/m/F5-VcUZtBAAJ Explanation}
  */
 class ResizeObserverSingleton {
 	/** */
diff --git a/packages/svelte/tests/runtime-runes/samples/transition-component/_config.js b/packages/svelte/tests/runtime-runes/samples/transition-component/_config.js
index 414a8b0cc2..1bdf3a5a2e 100644
--- a/packages/svelte/tests/runtime-runes/samples/transition-component/_config.js
+++ b/packages/svelte/tests/runtime-runes/samples/transition-component/_config.js
@@ -3,7 +3,7 @@ import { test } from '../../test';
 
 /**
  * $.component() should not break transition
- * https://github.com/sveltejs/svelte/issues/13645
+ * @see {@link https://github.com/sveltejs/svelte/issues/13645}
  */
 export default test({
 	test({ assert, raf, target }) {
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index 730e0ff655..62c0e210be 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -3188,7 +3188,7 @@ declare module 'svelte/types/compiler/interfaces' {
  * let count = $state(0);
  * ```
  *
- * https://svelte.dev/docs/svelte/$state
+ * @see {@link https://svelte.dev/docs/svelte/$state Documentation}
  *
  * @param initial The initial value
  */
@@ -3298,7 +3298,7 @@ declare namespace $state {
 	 * </button>
 	 * ```
 	 *
-	 * https://svelte.dev/docs/svelte/$state#$state.raw
+	 * @see {@link https://svelte.dev/docs/svelte/$state#$state.raw Documentation}
 	 *
 	 * @param initial The initial value
 	 */
@@ -3319,7 +3319,7 @@ declare namespace $state {
 	 * </script>
 	 * ```
 	 *
-	 * https://svelte.dev/docs/svelte/$state#$state.snapshot
+	 * @see {@link https://svelte.dev/docs/svelte/$state#$state.snapshot Documentation}
 	 *
 	 * @param state The value to snapshot
 	 */
@@ -3359,7 +3359,7 @@ declare namespace $state {
  * let double = $derived(count * 2);
  * ```
  *
- * https://svelte.dev/docs/svelte/$derived
+ * @see {@link https://svelte.dev/docs/svelte/$derived Documentation}
  *
  * @param expression The derived state expression
  */
@@ -3381,7 +3381,7 @@ declare namespace $derived {
 	 * });
 	 * ```
 	 *
-	 * https://svelte.dev/docs/svelte/$derived#$derived.by
+	 * @see {@link https://svelte.dev/docs/svelte/$derived#$derived.by Documentation}
 	 */
 	export function by<T>(fn: () => T): T;
 
@@ -3423,7 +3423,7 @@ declare namespace $derived {
  *
  * Does not run during server-side rendering.
  *
- * https://svelte.dev/docs/svelte/$effect
+ * @see {@link https://svelte.dev/docs/svelte/$effect Documentation}
  * @param fn The function to execute
  */
 declare function $effect(fn: () => void | (() => void)): void;
@@ -3442,7 +3442,7 @@ declare namespace $effect {
 	 *
 	 * Does not run during server-side rendering.
 	 *
-	 * https://svelte.dev/docs/svelte/$effect#$effect.pre
+	 * @see {@link https://svelte.dev/docs/svelte/$effect#$effect.pre Documentation}
 	 * @param fn The function to execute
 	 */
 	export function pre(fn: () => void | (() => void)): void;
@@ -3450,7 +3450,7 @@ declare namespace $effect {
 	/**
 	 * Returns the number of promises that are pending in the current boundary, not including child boundaries.
 	 *
-	 * https://svelte.dev/docs/svelte/$effect#$effect.pending
+	 * @see {@link https://svelte.dev/docs/svelte/$effect#$effect.pending Documentation}
 	 */
 	export function pending(): number;
 
@@ -3472,7 +3472,7 @@ declare namespace $effect {
 	 *
 	 * This allows you to (for example) add things like subscriptions without causing memory leaks, by putting them in child effects.
 	 *
-	 * https://svelte.dev/docs/svelte/$effect#$effect.tracking
+	 * @see {@link https://svelte.dev/docs/svelte/$effect#$effect.tracking Documentation}
 	 */
 	export function tracking(): boolean;
 
@@ -3500,7 +3500,7 @@ declare namespace $effect {
 	 * <button onclick={() => cleanup()}>cleanup</button>
 	 * ```
 	 *
-	 * https://svelte.dev/docs/svelte/$effect#$effect.root
+	 * @see {@link https://svelte.dev/docs/svelte/$effect#$effect.root Documentation}
 	 */
 	export function root(fn: () => void | (() => void)): () => void;
 
@@ -3536,7 +3536,7 @@ declare namespace $effect {
  * let { optionalProp = 42, requiredProp, bindableProp = $bindable() }: { optionalProp?: number; requiredProps: string; bindableProp: boolean } = $props();
  * ```
  *
- * https://svelte.dev/docs/svelte/$props
+ * @see {@link https://svelte.dev/docs/svelte/$props Documentation}
  */
 declare function $props(): any;
 
@@ -3582,7 +3582,7 @@ declare namespace $props {
  * let { propName = $bindable() }: { propName: boolean } = $props();
  * ```
  *
- * https://svelte.dev/docs/svelte/$bindable
+ * @see {@link https://svelte.dev/docs/svelte/$bindable Documentation}
  */
 declare function $bindable<T>(fallback?: T): T;
 
@@ -3628,7 +3628,7 @@ declare namespace $bindable {
  * $inspect(x, y).with(() => { debugger; });
  * ```
  *
- * https://svelte.dev/docs/svelte/$inspect
+ * @see {@link https://svelte.dev/docs/svelte/$inspect Documentation}
  */
 declare function $inspect<T extends any[]>(
 	...values: T
@@ -3694,7 +3694,7 @@ declare namespace $inspect {
  *
  * Only available inside custom element components, and only on the client-side.
  *
- * https://svelte.dev/docs/svelte/$host
+ * @see {@link https://svelte.dev/docs/svelte/$host Documentation}
  */
 declare function $host<El extends HTMLElement = HTMLElement>(): El;
 

From bb00d5b6e75da491bcee7860d3428458fd2f46ef Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Fri, 6 Feb 2026 15:05:08 -0500
Subject: [PATCH 132/142] Version Packages (#17615)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/chatty-mammals-find.md         |  5 -----
 .changeset/clear-olives-share.md          |  5 -----
 .changeset/fix-each-bind-store-logical.md |  5 -----
 .changeset/fix-menu-element-a11y-roles.md |  5 -----
 .changeset/forty-worlds-attack.md         |  5 -----
 .changeset/loud-bottles-own.md            |  5 -----
 .changeset/orange-ants-greet.md           |  5 -----
 .changeset/poor-students-nail.md          |  5 -----
 .changeset/sharp-snakes-poke.md           |  5 -----
 .changeset/tiny-owls-pay.md               |  5 -----
 packages/svelte/CHANGELOG.md              | 26 +++++++++++++++++++++++
 packages/svelte/package.json              |  2 +-
 packages/svelte/src/version.js            |  2 +-
 13 files changed, 28 insertions(+), 52 deletions(-)
 delete mode 100644 .changeset/chatty-mammals-find.md
 delete mode 100644 .changeset/clear-olives-share.md
 delete mode 100644 .changeset/fix-each-bind-store-logical.md
 delete mode 100644 .changeset/fix-menu-element-a11y-roles.md
 delete mode 100644 .changeset/forty-worlds-attack.md
 delete mode 100644 .changeset/loud-bottles-own.md
 delete mode 100644 .changeset/orange-ants-greet.md
 delete mode 100644 .changeset/poor-students-nail.md
 delete mode 100644 .changeset/sharp-snakes-poke.md
 delete mode 100644 .changeset/tiny-owls-pay.md

diff --git a/.changeset/chatty-mammals-find.md b/.changeset/chatty-mammals-find.md
deleted file mode 100644
index 373dc0059a..0000000000
--- a/.changeset/chatty-mammals-find.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: ensure infinite effect loops are cleared after flushing
diff --git a/.changeset/clear-olives-share.md b/.changeset/clear-olives-share.md
deleted file mode 100644
index 975b2b21b6..0000000000
--- a/.changeset/clear-olives-share.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: allow `{#key NaN}`
diff --git a/.changeset/fix-each-bind-store-logical.md b/.changeset/fix-each-bind-store-logical.md
deleted file mode 100644
index 1327015124..0000000000
--- a/.changeset/fix-each-bind-store-logical.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: detect store in each block expression regardless of AST shape
diff --git a/.changeset/fix-menu-element-a11y-roles.md b/.changeset/fix-menu-element-a11y-roles.md
deleted file mode 100644
index 75cfe8d310..0000000000
--- a/.changeset/fix-menu-element-a11y-roles.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: treat `<menu>` like `<ul>`/`<ol>` for a11y role checks
diff --git a/.changeset/forty-worlds-attack.md b/.changeset/forty-worlds-attack.md
deleted file mode 100644
index 52bb3644c0..0000000000
--- a/.changeset/forty-worlds-attack.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: add vite-ignore comment inside dynamic crypto import
diff --git a/.changeset/loud-bottles-own.md b/.changeset/loud-bottles-own.md
deleted file mode 100644
index 493dc6c47f..0000000000
--- a/.changeset/loud-bottles-own.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-chore: wrap JSDoc URLs in `@see` and `@link` tags
diff --git a/.changeset/orange-ants-greet.md b/.changeset/orange-ants-greet.md
deleted file mode 100644
index 6f7c684fee..0000000000
--- a/.changeset/orange-ants-greet.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': minor
----
-
-feat: allow use of createContext when instantiating components programmatically
diff --git a/.changeset/poor-students-nail.md b/.changeset/poor-students-nail.md
deleted file mode 100644
index cee650c002..0000000000
--- a/.changeset/poor-students-nail.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-"svelte": patch
----
-
-fix: properly hydrate already-resolved async blocks
diff --git a/.changeset/sharp-snakes-poke.md b/.changeset/sharp-snakes-poke.md
deleted file mode 100644
index 7f7f8aa7b2..0000000000
--- a/.changeset/sharp-snakes-poke.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: emit `each_key_duplicate` error in production
diff --git a/.changeset/tiny-owls-pay.md b/.changeset/tiny-owls-pay.md
deleted file mode 100644
index ac25500258..0000000000
--- a/.changeset/tiny-owls-pay.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: exit resolved async blocks on correct node when hydrating
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index a71effd5dd..b251e778ef 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,31 @@
 # svelte
 
+## 5.50.0
+
+### Minor Changes
+
+- feat: allow use of createContext when instantiating components programmatically ([#17575](https://github.com/sveltejs/svelte/pull/17575))
+
+### Patch Changes
+
+- fix: ensure infinite effect loops are cleared after flushing ([#17601](https://github.com/sveltejs/svelte/pull/17601))
+
+- fix: allow `{#key NaN}` ([#17642](https://github.com/sveltejs/svelte/pull/17642))
+
+- fix: detect store in each block expression regardless of AST shape ([#17636](https://github.com/sveltejs/svelte/pull/17636))
+
+- fix: treat `<menu>` like `<ul>`/`<ol>` for a11y role checks ([#17638](https://github.com/sveltejs/svelte/pull/17638))
+
+- fix: add vite-ignore comment inside dynamic crypto import ([#17623](https://github.com/sveltejs/svelte/pull/17623))
+
+- chore: wrap JSDoc URLs in `@see` and `@link` tags ([#17617](https://github.com/sveltejs/svelte/pull/17617))
+
+- fix: properly hydrate already-resolved async blocks ([#17641](https://github.com/sveltejs/svelte/pull/17641))
+
+- fix: emit `each_key_duplicate` error in production ([#16724](https://github.com/sveltejs/svelte/pull/16724))
+
+- fix: exit resolved async blocks on correct node when hydrating ([#17640](https://github.com/sveltejs/svelte/pull/17640))
+
 ## 5.49.2
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 48f492783f..82d0d1a8ed 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": "5.49.2",
+  "version": "5.50.0",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 31538c3fe7..3aefb2e1f6 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 = '5.49.2';
+export const VERSION = '5.50.0';
 export const PUBLIC_VERSION = '5';

From 9749ee869c4a3473a50a3a42daa2ee8896d41898 Mon Sep 17 00:00:00 2001
From: 7nik <kifiranet@gmail.com>
Date: Sat, 7 Feb 2026 01:09:42 +0200
Subject: [PATCH 133/142] chore: add xhtml tests (#17597)

* add xhtml tests

* unused

* tweak

* more tests

* tweak

* we don't need to actually check the HTML - if it's malformed in SSR or mount, it will throw

* same here

* unused, so we can revert this

* and this

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 eslint.config.js                              |  1 +
 packages/svelte/tests/html_equal.js           | 16 ++++++++--------
 .../samples/attribute-quotes/_config.js       |  3 +++
 .../samples/attribute-quotes/main.svelte      |  2 ++
 .../samples/autoclosed-tags/_config.js        |  3 +++
 .../samples/autoclosed-tags/main.svelte       |  6 ++++++
 .../samples/boolean-attributes/_config.js     |  5 +++++
 .../samples/boolean-attributes/main.svelte    |  1 +
 .../samples/comment-marker/_config.js         |  3 +++
 .../samples/comment-marker/main.svelte        |  1 +
 .../runtime-xhtml/samples/is-xhtml/_config.js |  8 ++++++++
 .../samples/is-xhtml/main.svelte              |  5 +++++
 .../samples/void-tags/_config.js              |  3 +++
 .../samples/void-tags/main.svelte             | 15 +++++++++++++++
 packages/svelte/tests/runtime-xhtml/test.ts   |  9 +++++++++
 vitest-xhtml-environment.ts                   | 19 +++++++++++++++++++
 16 files changed, 92 insertions(+), 8 deletions(-)
 create mode 100644 packages/svelte/tests/runtime-xhtml/samples/attribute-quotes/_config.js
 create mode 100644 packages/svelte/tests/runtime-xhtml/samples/attribute-quotes/main.svelte
 create mode 100644 packages/svelte/tests/runtime-xhtml/samples/autoclosed-tags/_config.js
 create mode 100644 packages/svelte/tests/runtime-xhtml/samples/autoclosed-tags/main.svelte
 create mode 100644 packages/svelte/tests/runtime-xhtml/samples/boolean-attributes/_config.js
 create mode 100644 packages/svelte/tests/runtime-xhtml/samples/boolean-attributes/main.svelte
 create mode 100644 packages/svelte/tests/runtime-xhtml/samples/comment-marker/_config.js
 create mode 100644 packages/svelte/tests/runtime-xhtml/samples/comment-marker/main.svelte
 create mode 100644 packages/svelte/tests/runtime-xhtml/samples/is-xhtml/_config.js
 create mode 100644 packages/svelte/tests/runtime-xhtml/samples/is-xhtml/main.svelte
 create mode 100644 packages/svelte/tests/runtime-xhtml/samples/void-tags/_config.js
 create mode 100644 packages/svelte/tests/runtime-xhtml/samples/void-tags/main.svelte
 create mode 100644 packages/svelte/tests/runtime-xhtml/test.ts
 create mode 100644 vitest-xhtml-environment.ts

diff --git a/eslint.config.js b/eslint.config.js
index 0e0e0bc729..04d9294394 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -102,6 +102,7 @@ export default [
 			'playgrounds/sandbox/**',
 			// exclude top level config files
 			'*.config.js',
+			'vitest-xhtml-environment.ts',
 			// documentation can contain invalid examples
 			'documentation',
 			'tmp/**'
diff --git a/packages/svelte/tests/html_equal.js b/packages/svelte/tests/html_equal.js
index 76a4a957a5..cdb8f52e37 100644
--- a/packages/svelte/tests/html_equal.js
+++ b/packages/svelte/tests/html_equal.js
@@ -9,7 +9,9 @@ function clean_children(node, opts) {
 	let previous = null;
 	let has_element_children = false;
 	let template =
-		node.nodeName === 'TEMPLATE' ? /** @type {HTMLTemplateElement} */ (node) : undefined;
+		node.nodeName.toUpperCase() === 'TEMPLATE'
+			? /** @type {HTMLTemplateElement} */ (node)
+			: undefined;
 
 	if (template) {
 		const div = document.createElement('div');
@@ -23,22 +25,20 @@ function clean_children(node, opts) {
 	});
 
 	attributes.forEach((attr) => {
-		node.removeAttribute(attr.name);
+		if (attr.name !== 'xmlns') node.removeAttribute(attr.name);
 	});
 
-	attributes.forEach((attr) => {
+	attributes.forEach(({ name, value }) => {
 		// Strip out the special onload/onerror hydration events from the test output
-		if ((attr.name === 'onload' || attr.name === 'onerror') && attr.value === 'this.__e=event') {
+		if (['onload', 'onerror', 'xmlns'].includes(name) && value === 'this.__e=event') {
 			return;
 		}
 
-		let value = attr.value;
-
-		if (attr.name === 'class') {
+		if (name === 'class') {
 			value = value.replace(/svelte-\w+/, 'svelte-xyz123');
 		}
 
-		node.setAttribute(attr.name, value);
+		node.setAttribute(name, value);
 	});
 
 	for (let child of [...node.childNodes]) {
diff --git a/packages/svelte/tests/runtime-xhtml/samples/attribute-quotes/_config.js b/packages/svelte/tests/runtime-xhtml/samples/attribute-quotes/_config.js
new file mode 100644
index 0000000000..f47bee71df
--- /dev/null
+++ b/packages/svelte/tests/runtime-xhtml/samples/attribute-quotes/_config.js
@@ -0,0 +1,3 @@
+import { test } from '../../test';
+
+export default test({});
diff --git a/packages/svelte/tests/runtime-xhtml/samples/attribute-quotes/main.svelte b/packages/svelte/tests/runtime-xhtml/samples/attribute-quotes/main.svelte
new file mode 100644
index 0000000000..82db611c12
--- /dev/null
+++ b/packages/svelte/tests/runtime-xhtml/samples/attribute-quotes/main.svelte
@@ -0,0 +1,2 @@
+<div foo=bar></div>
+<div foo='bar baz'></div>
diff --git a/packages/svelte/tests/runtime-xhtml/samples/autoclosed-tags/_config.js b/packages/svelte/tests/runtime-xhtml/samples/autoclosed-tags/_config.js
new file mode 100644
index 0000000000..f47bee71df
--- /dev/null
+++ b/packages/svelte/tests/runtime-xhtml/samples/autoclosed-tags/_config.js
@@ -0,0 +1,3 @@
+import { test } from '../../test';
+
+export default test({});
diff --git a/packages/svelte/tests/runtime-xhtml/samples/autoclosed-tags/main.svelte b/packages/svelte/tests/runtime-xhtml/samples/autoclosed-tags/main.svelte
new file mode 100644
index 0000000000..18a4463ce1
--- /dev/null
+++ b/packages/svelte/tests/runtime-xhtml/samples/autoclosed-tags/main.svelte
@@ -0,0 +1,6 @@
+<ul><li><li></ul>
+<dl><dt><dd><dd></dl>
+<p><p><div></div>
+<ruby><rp><rt><rt></ruby>
+<select><option><optgroup><optgroup></select>
+<table><thead><tbody><tfoot><tbody><tr><td><th></tr><tr></table>
diff --git a/packages/svelte/tests/runtime-xhtml/samples/boolean-attributes/_config.js b/packages/svelte/tests/runtime-xhtml/samples/boolean-attributes/_config.js
new file mode 100644
index 0000000000..f965e04b02
--- /dev/null
+++ b/packages/svelte/tests/runtime-xhtml/samples/boolean-attributes/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	skip: true
+});
diff --git a/packages/svelte/tests/runtime-xhtml/samples/boolean-attributes/main.svelte b/packages/svelte/tests/runtime-xhtml/samples/boolean-attributes/main.svelte
new file mode 100644
index 0000000000..3d2fc88d10
--- /dev/null
+++ b/packages/svelte/tests/runtime-xhtml/samples/boolean-attributes/main.svelte
@@ -0,0 +1 @@
+<input disabled hidden>
diff --git a/packages/svelte/tests/runtime-xhtml/samples/comment-marker/_config.js b/packages/svelte/tests/runtime-xhtml/samples/comment-marker/_config.js
new file mode 100644
index 0000000000..f47bee71df
--- /dev/null
+++ b/packages/svelte/tests/runtime-xhtml/samples/comment-marker/_config.js
@@ -0,0 +1,3 @@
+import { test } from '../../test';
+
+export default test({});
diff --git a/packages/svelte/tests/runtime-xhtml/samples/comment-marker/main.svelte b/packages/svelte/tests/runtime-xhtml/samples/comment-marker/main.svelte
new file mode 100644
index 0000000000..8dd87ce81e
--- /dev/null
+++ b/packages/svelte/tests/runtime-xhtml/samples/comment-marker/main.svelte
@@ -0,0 +1 @@
+{#each [1,2] as i}{i}{/each}
diff --git a/packages/svelte/tests/runtime-xhtml/samples/is-xhtml/_config.js b/packages/svelte/tests/runtime-xhtml/samples/is-xhtml/_config.js
new file mode 100644
index 0000000000..52dddb4ad7
--- /dev/null
+++ b/packages/svelte/tests/runtime-xhtml/samples/is-xhtml/_config.js
@@ -0,0 +1,8 @@
+import { test } from '../../test';
+
+export default test({
+	mode: ['client'],
+	test({ assert, target }) {
+		assert.htmlEqual(target.innerHTML, `<div>div</div>`);
+	}
+});
diff --git a/packages/svelte/tests/runtime-xhtml/samples/is-xhtml/main.svelte b/packages/svelte/tests/runtime-xhtml/samples/is-xhtml/main.svelte
new file mode 100644
index 0000000000..27a4378d0f
--- /dev/null
+++ b/packages/svelte/tests/runtime-xhtml/samples/is-xhtml/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	let elem = $state();
+	let nodeName = $derived(elem?.nodeName);
+</script>
+<div bind:this={elem}>{nodeName}</div>
diff --git a/packages/svelte/tests/runtime-xhtml/samples/void-tags/_config.js b/packages/svelte/tests/runtime-xhtml/samples/void-tags/_config.js
new file mode 100644
index 0000000000..f47bee71df
--- /dev/null
+++ b/packages/svelte/tests/runtime-xhtml/samples/void-tags/_config.js
@@ -0,0 +1,3 @@
+import { test } from '../../test';
+
+export default test({});
diff --git a/packages/svelte/tests/runtime-xhtml/samples/void-tags/main.svelte b/packages/svelte/tests/runtime-xhtml/samples/void-tags/main.svelte
new file mode 100644
index 0000000000..08ea2838b3
--- /dev/null
+++ b/packages/svelte/tests/runtime-xhtml/samples/void-tags/main.svelte
@@ -0,0 +1,15 @@
+<area alt="">
+<base>
+<br>
+<col>
+<embed>
+<hr>
+<img alt="">
+<input>
+<keygen>
+<link>
+<meta>
+<param>
+<source>
+<track>
+<wbr>
diff --git a/packages/svelte/tests/runtime-xhtml/test.ts b/packages/svelte/tests/runtime-xhtml/test.ts
new file mode 100644
index 0000000000..416300dc58
--- /dev/null
+++ b/packages/svelte/tests/runtime-xhtml/test.ts
@@ -0,0 +1,9 @@
+// @vitest-environment vitest-xhtml-environment.ts
+
+import { runtime_suite, ok } from '../runtime-legacy/shared';
+
+const { test, run } = runtime_suite(true);
+
+export { test, ok };
+
+await run(__dirname);
diff --git a/vitest-xhtml-environment.ts b/vitest-xhtml-environment.ts
new file mode 100644
index 0000000000..dc8b271440
--- /dev/null
+++ b/vitest-xhtml-environment.ts
@@ -0,0 +1,19 @@
+import { type Environment, builtinEnvironments } from 'vitest/environments';
+
+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">
+<html xmlns="http://www.w3.org/1999/xhtml"><head></head><body></body></html>`;
+
+export default <Environment>{
+	name: 'jsdom-xhtml',
+	transformMode: 'web',
+	setup(global, { jsdom = {} }) {
+		return builtinEnvironments.jsdom.setup(global, {
+			jsdom: {
+				...jsdom,
+				html: xhtml_page,
+				contentType: 'application/xhtml+xml'
+			}
+		});
+	}
+};

From 6ad6eb1bbf5bce809eb8e2f4495b422fc7c60c51 Mon Sep 17 00:00:00 2001
From: Michel Heusschen <59014050+michelheusschen@users.noreply.github.com>
Date: Sat, 7 Feb 2026 00:38:22 +0100
Subject: [PATCH 134/142] docs: add section on conditional attachments (#17599)

---
 documentation/docs/03-template-syntax/09-@attach.md | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/documentation/docs/03-template-syntax/09-@attach.md b/documentation/docs/03-template-syntax/09-@attach.md
index b25fbb32a6..8814ead487 100644
--- a/documentation/docs/03-template-syntax/09-@attach.md
+++ b/documentation/docs/03-template-syntax/09-@attach.md
@@ -82,6 +82,14 @@ Attachments can also be created inline ([demo](/playground/untitled#H4sIAAAAAAAA
 > [!NOTE]
 > The nested effect runs whenever `color` changes, while the outer effect (where `canvas.getContext(...)` is called) only runs once, since it doesn't read any reactive state.
 
+## Conditional attachments
+
+Falsy values like `false` or `undefined` are treated as no attachment, enabling conditional usage:
+
+```svelte
+<div {@attach enabled && myAttachment}>...</div>
+```
+
 ## Passing attachments to components
 
 When used on a component, `{@attach ...}` will create a prop whose key is a [`Symbol`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol). If the component then [spreads](/tutorial/svelte/spread-props) props onto an element, the element will receive those attachments.

From d047bc6e2a7238fadff45d09a779a17dc14aeafd Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Sat, 7 Feb 2026 19:49:03 -0500
Subject: [PATCH 135/142] fix: render boolean attribute values as empty strings
 for XHTML compliance (#17648)

---
 .changeset/tired-cities-wink.md                           | 5 +++++
 .../phases/3-transform/client/visitors/RegularElement.js  | 5 +----
 .../phases/3-transform/server/visitors/shared/element.js  | 8 +-------
 .../runtime-xhtml/samples/boolean-attributes/_config.js   | 4 +---
 .../skip-static-subtree/_expected/server/index.svelte.js  | 2 +-
 5 files changed, 9 insertions(+), 15 deletions(-)
 create mode 100644 .changeset/tired-cities-wink.md

diff --git a/.changeset/tired-cities-wink.md b/.changeset/tired-cities-wink.md
new file mode 100644
index 0000000000..a319b5b2b0
--- /dev/null
+++ b/.changeset/tired-cities-wink.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: render boolean attribute values as empty strings for XHTML compliance
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 720522beaf..f651586dd8 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
@@ -256,10 +256,7 @@ export function RegularElement(node, context) {
 				}
 
 				if (name !== 'class' || value) {
-					context.state.template.set_prop(
-						attribute.name,
-						is_boolean_attribute(name) && value === true ? undefined : value === true ? '' : value
-					);
+					context.state.template.set_prop(attribute.name, value === true ? '' : value);
 				}
 			} else if (name === 'autofocus') {
 				let { value } = build_attribute_value(attribute.value, context);
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 979efef6b9..f4f491c056 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
@@ -235,13 +235,7 @@ export function build_element_attributes(node, context, transform) {
 
 				if (name !== 'class' || literal_value) {
 					context.state.template.push(
-						b.literal(
-							` ${attribute.name}${
-								is_boolean_attribute(name) && literal_value === true
-									? ''
-									: `="${literal_value === true ? '' : String(literal_value)}"`
-							}`
-						)
+						b.literal(` ${attribute.name}="${literal_value === true ? '' : String(literal_value)}"`)
 					);
 				}
 
diff --git a/packages/svelte/tests/runtime-xhtml/samples/boolean-attributes/_config.js b/packages/svelte/tests/runtime-xhtml/samples/boolean-attributes/_config.js
index f965e04b02..f47bee71df 100644
--- a/packages/svelte/tests/runtime-xhtml/samples/boolean-attributes/_config.js
+++ b/packages/svelte/tests/runtime-xhtml/samples/boolean-attributes/_config.js
@@ -1,5 +1,3 @@
 import { test } from '../../test';
 
-export default test({
-	skip: true
-});
+export default test({});
diff --git a/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/server/index.svelte.js
index 7a9f6193d7..b1babb514c 100644
--- a/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/server/index.svelte.js
@@ -3,7 +3,7 @@ import * as $ from 'svelte/internal/server';
 export default function Skip_static_subtree($$renderer, $$props) {
 	let { title, content } = $$props;
 
-	$$renderer.push(`<header><nav><a href="/">Home</a> <a href="/away">Away</a></nav></header> <main><h1>${$.escape(title)}</h1> <div class="static"><p>we don't need to traverse these nodes</p></div> <p>or</p> <p>these</p> <p>ones</p> ${$.html(content)} <p>these</p> <p>trailing</p> <p>nodes</p> <p>can</p> <p>be</p> <p>completely</p> <p>ignored</p></main> <cant-skip><custom-elements with="attributes"></custom-elements></cant-skip> <div><input autofocus/></div> <div><source muted/></div> <select>`);
+	$$renderer.push(`<header><nav><a href="/">Home</a> <a href="/away">Away</a></nav></header> <main><h1>${$.escape(title)}</h1> <div class="static"><p>we don't need to traverse these nodes</p></div> <p>or</p> <p>these</p> <p>ones</p> ${$.html(content)} <p>these</p> <p>trailing</p> <p>nodes</p> <p>can</p> <p>be</p> <p>completely</p> <p>ignored</p></main> <cant-skip><custom-elements with="attributes"></custom-elements></cant-skip> <div><input autofocus=""/></div> <div><source muted=""/></div> <select>`);
 
 	$$renderer.option({ value: 'a' }, ($$renderer) => {
 		$$renderer.push(`a`);

From 0a404c986380f7a9880733864229c4be9e08e098 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Sun, 8 Feb 2026 01:51:21 +0100
Subject: [PATCH 136/142] fix: prevent async render tag hydration mismatches
 (#17652)

If the render tag is wrapped in `$.async`, that `$.async` call already contains surrounding markers, so we must not add our own to avoid hydration mismatches. Related to #17641, fixes #17225
---
 .changeset/two-places-speak.md                    |  5 +++++
 .../3-transform/server/visitors/RenderTag.js      |  4 +++-
 .../samples/async-render-hydration/_config.js     | 11 +++++++++++
 .../samples/async-render-hydration/main.svelte    | 15 +++++++++++++++
 4 files changed, 34 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/two-places-speak.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-render-hydration/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-render-hydration/main.svelte

diff --git a/.changeset/two-places-speak.md b/.changeset/two-places-speak.md
new file mode 100644
index 0000000000..957377b26b
--- /dev/null
+++ b/.changeset/two-places-speak.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: prevent async render tag hydration mismatches
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/RenderTag.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/RenderTag.js
index fe20e85e1b..ac671c0188 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/RenderTag.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/RenderTag.js
@@ -37,7 +37,9 @@ export function RenderTag(node, context) {
 
 	context.state.template.push(...optimiser.render_block([statement]));
 
-	if (!context.state.is_standalone) {
+	// If the render tag is wrapped in $.async, that $.async call already contains surrounding markers,
+	// so we don't need to (or rather must not, to avoid hydration mismatches) add our own.
+	if (!optimiser.is_async() && !context.state.is_standalone) {
 		context.state.template.push(empty_comment);
 	}
 }
diff --git a/packages/svelte/tests/runtime-runes/samples/async-render-hydration/_config.js b/packages/svelte/tests/runtime-runes/samples/async-render-hydration/_config.js
new file mode 100644
index 0000000000..2e37b0b9ac
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-render-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, `Count: 1 Double: 2`);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-render-hydration/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-render-hydration/main.svelte
new file mode 100644
index 0000000000..e26ff87567
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-render-hydration/main.svelte
@@ -0,0 +1,15 @@
+<script lang="ts">
+	let count = $state(1);
+	async function getDouble(count: number) {
+		return count * 2;
+	}
+	const double = $derived(await getDouble(count));
+</script>
+
+Count: {count}
+
+{#snippet ssr(num: number)}
+	{num}
+{/snippet}
+
+Double: {@render ssr(double)}

From 67c4a3811770daeac3ec1df48a99f39659e4a980 Mon Sep 17 00:00:00 2001
From: Mohit Kourav <mohitdas852@gmail.com>
Date: Sun, 8 Feb 2026 06:22:56 +0530
Subject: [PATCH 137/142] docs: add explanatory comments to empty catch blocks
 (#17651)

* docs: add explanatory comments to empty catch blocks

* Update equality.js

* Refactor error handling in inspect.js

Simplified error handling in render_effect.

* Update inspect.js

* Update packages/svelte/src/internal/client/dev/console-log.js

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 packages/svelte/src/internal/client/dev/console-log.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/svelte/src/internal/client/dev/console-log.js b/packages/svelte/src/internal/client/dev/console-log.js
index d314359ef6..38860eb767 100644
--- a/packages/svelte/src/internal/client/dev/console-log.js
+++ b/packages/svelte/src/internal/client/dev/console-log.js
@@ -28,7 +28,9 @@ export function log_if_contains_state(method, ...objects) {
 				// eslint-disable-next-line no-console
 				console.log('%c[snapshot]', 'color: grey', ...transformed);
 			}
-		} catch {}
+		} catch {
+			// Errors can occur when trying to snapshot objects with getters that throw or non-enumerable properties.
+		}
 	});
 
 	return objects;

From f09785424b87e52cefe27d7ed725c2559829e2e6 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Mon, 9 Feb 2026 14:37:05 -0500
Subject: [PATCH 138/142] docs: add crosslinks (#17663)

---
 documentation/docs/02-runes/02-$state.md                 | 1 +
 documentation/docs/02-runes/03-$derived.md               | 1 +
 documentation/docs/02-runes/04-$effect.md                | 1 +
 documentation/docs/02-runes/05-$props.md                 | 1 +
 documentation/docs/02-runes/07-$inspect.md               | 1 +
 documentation/docs/03-template-syntax/02-if.md           | 1 +
 documentation/docs/03-template-syntax/03-each.md         | 1 +
 documentation/docs/03-template-syntax/04-key.md          | 1 +
 documentation/docs/03-template-syntax/05-await.md        | 1 +
 documentation/docs/03-template-syntax/08-@html.md        | 1 +
 documentation/docs/03-template-syntax/09-@attach.md      | 1 +
 documentation/docs/03-template-syntax/14-transition.md   | 1 +
 documentation/docs/03-template-syntax/15-in-and-out.md   | 3 ++-
 documentation/docs/03-template-syntax/17-style.md        | 1 +
 documentation/docs/03-template-syntax/18-class.md        | 1 +
 documentation/docs/04-styling/01-scoped-styles.md        | 1 +
 documentation/docs/04-styling/02-global-styles.md        | 1 +
 documentation/docs/04-styling/03-custom-properties.md    | 1 +
 documentation/docs/98-reference/21-svelte-attachments.md | 1 +
 documentation/docs/98-reference/21-svelte-transition.md  | 1 +
 20 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/documentation/docs/02-runes/02-$state.md b/documentation/docs/02-runes/02-$state.md
index 6fbf3b8895..d763b6578f 100644
--- a/documentation/docs/02-runes/02-$state.md
+++ b/documentation/docs/02-runes/02-$state.md
@@ -1,5 +1,6 @@
 ---
 title: $state
+tags: rune-state
 ---
 
 The `$state` rune allows you to create _reactive state_, which means that your UI _reacts_ when it changes.
diff --git a/documentation/docs/02-runes/03-$derived.md b/documentation/docs/02-runes/03-$derived.md
index d3e46eb22d..35cb6c1912 100644
--- a/documentation/docs/02-runes/03-$derived.md
+++ b/documentation/docs/02-runes/03-$derived.md
@@ -1,5 +1,6 @@
 ---
 title: $derived
+tags: rune-derived
 ---
 
 Derived state is declared with the `$derived` rune:
diff --git a/documentation/docs/02-runes/04-$effect.md b/documentation/docs/02-runes/04-$effect.md
index 6c42f55795..d41c5b8e6a 100644
--- a/documentation/docs/02-runes/04-$effect.md
+++ b/documentation/docs/02-runes/04-$effect.md
@@ -1,5 +1,6 @@
 ---
 title: $effect
+tags: rune-effect
 ---
 
 Effects are functions that run when state updates, and can be used for things like calling third-party libraries, drawing on `<canvas>` elements, or making network requests. They only run in the browser, not during server-side rendering.
diff --git a/documentation/docs/02-runes/05-$props.md b/documentation/docs/02-runes/05-$props.md
index bd5ae16853..737cdf523e 100644
--- a/documentation/docs/02-runes/05-$props.md
+++ b/documentation/docs/02-runes/05-$props.md
@@ -1,5 +1,6 @@
 ---
 title: $props
+tags: rune-props
 ---
 
 The inputs to a component are referred to as _props_, which is short for _properties_. You pass props to components just like you pass attributes to elements:
diff --git a/documentation/docs/02-runes/07-$inspect.md b/documentation/docs/02-runes/07-$inspect.md
index 6d47e30e27..f67e250b45 100644
--- a/documentation/docs/02-runes/07-$inspect.md
+++ b/documentation/docs/02-runes/07-$inspect.md
@@ -1,5 +1,6 @@
 ---
 title: $inspect
+tags: rune-inspect
 ---
 
 > [!NOTE] `$inspect` only works during development. In a production build it becomes a noop.
diff --git a/documentation/docs/03-template-syntax/02-if.md b/documentation/docs/03-template-syntax/02-if.md
index 1378733e6f..499f6d219c 100644
--- a/documentation/docs/03-template-syntax/02-if.md
+++ b/documentation/docs/03-template-syntax/02-if.md
@@ -1,5 +1,6 @@
 ---
 title: {#if ...}
+tags: template-if
 ---
 
 ```svelte
diff --git a/documentation/docs/03-template-syntax/03-each.md b/documentation/docs/03-template-syntax/03-each.md
index 57ed0def71..424e16a18a 100644
--- a/documentation/docs/03-template-syntax/03-each.md
+++ b/documentation/docs/03-template-syntax/03-each.md
@@ -1,5 +1,6 @@
 ---
 title: {#each ...}
+tags: template-each
 ---
 
 ```svelte
diff --git a/documentation/docs/03-template-syntax/04-key.md b/documentation/docs/03-template-syntax/04-key.md
index 10b6ab4358..6c88e28f86 100644
--- a/documentation/docs/03-template-syntax/04-key.md
+++ b/documentation/docs/03-template-syntax/04-key.md
@@ -1,5 +1,6 @@
 ---
 title: {#key ...}
+tags: template-key
 ---
 
 ```svelte
diff --git a/documentation/docs/03-template-syntax/05-await.md b/documentation/docs/03-template-syntax/05-await.md
index 842b3c7e32..aebaf8d33a 100644
--- a/documentation/docs/03-template-syntax/05-await.md
+++ b/documentation/docs/03-template-syntax/05-await.md
@@ -1,5 +1,6 @@
 ---
 title: {#await ...}
+tags: template-await
 ---
 
 ```svelte
diff --git a/documentation/docs/03-template-syntax/08-@html.md b/documentation/docs/03-template-syntax/08-@html.md
index 6d8a8be0c6..36b8ad36b3 100644
--- a/documentation/docs/03-template-syntax/08-@html.md
+++ b/documentation/docs/03-template-syntax/08-@html.md
@@ -1,5 +1,6 @@
 ---
 title: {@html ...}
+tags: template-html
 ---
 
 To inject raw HTML into your component, use the `{@html ...}` tag:
diff --git a/documentation/docs/03-template-syntax/09-@attach.md b/documentation/docs/03-template-syntax/09-@attach.md
index 8814ead487..0087923b15 100644
--- a/documentation/docs/03-template-syntax/09-@attach.md
+++ b/documentation/docs/03-template-syntax/09-@attach.md
@@ -1,5 +1,6 @@
 ---
 title: {@attach ...}
+tags: attachments
 ---
 
 Attachments are functions that run in an [effect]($effect) when an element is mounted to the DOM or when [state]($state) read inside the function updates.
diff --git a/documentation/docs/03-template-syntax/14-transition.md b/documentation/docs/03-template-syntax/14-transition.md
index c51175c272..9b14b7b25b 100644
--- a/documentation/docs/03-template-syntax/14-transition.md
+++ b/documentation/docs/03-template-syntax/14-transition.md
@@ -1,5 +1,6 @@
 ---
 title: transition:
+tags: transitions
 ---
 
 A _transition_ is triggered by an element entering or leaving the DOM as a result of a state change.
diff --git a/documentation/docs/03-template-syntax/15-in-and-out.md b/documentation/docs/03-template-syntax/15-in-and-out.md
index f4e37c845e..8adb62bf14 100644
--- a/documentation/docs/03-template-syntax/15-in-and-out.md
+++ b/documentation/docs/03-template-syntax/15-in-and-out.md
@@ -1,5 +1,6 @@
 ---
 title: in: and out:
+tags: transitions
 ---
 
 The `in:` and `out:` directives are identical to [`transition:`](transition), except that the resulting transitions are not bidirectional — an `in` transition will continue to 'play' alongside the `out` transition, rather than reversing, if the block is outroed while the transition is in progress. If an out transition is aborted, transitions will restart from scratch.
@@ -7,7 +8,7 @@ The `in:` and `out:` directives are identical to [`transition:`](transition), ex
 ```svelte
 <script>
   import { fade, fly } from 'svelte/transition';
-  
+
   let visible = $state(false);
 </script>
 
diff --git a/documentation/docs/03-template-syntax/17-style.md b/documentation/docs/03-template-syntax/17-style.md
index aa61cdcde3..8b25c221d6 100644
--- a/documentation/docs/03-template-syntax/17-style.md
+++ b/documentation/docs/03-template-syntax/17-style.md
@@ -1,5 +1,6 @@
 ---
 title: style:
+tags: template-style
 ---
 
 The `style:` directive provides a shorthand for setting multiple styles on an element.
diff --git a/documentation/docs/03-template-syntax/18-class.md b/documentation/docs/03-template-syntax/18-class.md
index db85db4b37..5d7cb3100d 100644
--- a/documentation/docs/03-template-syntax/18-class.md
+++ b/documentation/docs/03-template-syntax/18-class.md
@@ -1,5 +1,6 @@
 ---
 title: class
+tags: template-style
 ---
 
 There are two ways to set classes on elements: the `class` attribute, and the `class:` directive.
diff --git a/documentation/docs/04-styling/01-scoped-styles.md b/documentation/docs/04-styling/01-scoped-styles.md
index eae26d0cb1..cdfbeab19b 100644
--- a/documentation/docs/04-styling/01-scoped-styles.md
+++ b/documentation/docs/04-styling/01-scoped-styles.md
@@ -1,5 +1,6 @@
 ---
 title: Scoped styles
+tags: styles-scoped
 ---
 
 Svelte components can include a `<style>` element containing CSS that belongs to the component. This CSS is _scoped_ by default, meaning that styles will not apply to any elements on the page outside the component in question.
diff --git a/documentation/docs/04-styling/02-global-styles.md b/documentation/docs/04-styling/02-global-styles.md
index 8e9cf8d0cb..140b976dc5 100644
--- a/documentation/docs/04-styling/02-global-styles.md
+++ b/documentation/docs/04-styling/02-global-styles.md
@@ -1,5 +1,6 @@
 ---
 title: Global styles
+tags: styles-global
 ---
 
 ## :global(...)
diff --git a/documentation/docs/04-styling/03-custom-properties.md b/documentation/docs/04-styling/03-custom-properties.md
index 49984c6ce4..09faee3a98 100644
--- a/documentation/docs/04-styling/03-custom-properties.md
+++ b/documentation/docs/04-styling/03-custom-properties.md
@@ -1,5 +1,6 @@
 ---
 title: Custom properties
+tags: styles-custom-properties
 ---
 
 You can pass CSS custom properties — both static and dynamic — to components:
diff --git a/documentation/docs/98-reference/21-svelte-attachments.md b/documentation/docs/98-reference/21-svelte-attachments.md
index e446bdddc2..c414d3bbca 100644
--- a/documentation/docs/98-reference/21-svelte-attachments.md
+++ b/documentation/docs/98-reference/21-svelte-attachments.md
@@ -1,5 +1,6 @@
 ---
 title: svelte/attachments
+tags: attachments
 ---
 
 > MODULE: svelte/attachments
diff --git a/documentation/docs/98-reference/21-svelte-transition.md b/documentation/docs/98-reference/21-svelte-transition.md
index 396bc0aebf..e2ff6dbd0e 100644
--- a/documentation/docs/98-reference/21-svelte-transition.md
+++ b/documentation/docs/98-reference/21-svelte-transition.md
@@ -1,5 +1,6 @@
 ---
 title: svelte/transition
+tags: transitions
 ---
 
 > MODULE: svelte/transition

From 35c845e35deefb621f73b2f3d8845441c3669705 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Mon, 9 Feb 2026 20:58:37 -0500
Subject: [PATCH 139/142] Version Packages (#17653)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/tired-cities-wink.md | 5 -----
 .changeset/two-places-speak.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/tired-cities-wink.md
 delete mode 100644 .changeset/two-places-speak.md

diff --git a/.changeset/tired-cities-wink.md b/.changeset/tired-cities-wink.md
deleted file mode 100644
index a319b5b2b0..0000000000
--- a/.changeset/tired-cities-wink.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: render boolean attribute values as empty strings for XHTML compliance
diff --git a/.changeset/two-places-speak.md b/.changeset/two-places-speak.md
deleted file mode 100644
index 957377b26b..0000000000
--- a/.changeset/two-places-speak.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: prevent async render tag hydration mismatches
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index b251e778ef..3fcc8edfc1 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,13 @@
 # svelte
 
+## 5.50.1
+
+### Patch Changes
+
+- fix: render boolean attribute values as empty strings for XHTML compliance ([#17648](https://github.com/sveltejs/svelte/pull/17648))
+
+- fix: prevent async render tag hydration mismatches ([#17652](https://github.com/sveltejs/svelte/pull/17652))
+
 ## 5.50.0
 
 ### Minor Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 82d0d1a8ed..8ebb0a6b32 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": "5.50.0",
+  "version": "5.50.1",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 3aefb2e1f6..0af5fb8ca0 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 = '5.50.0';
+export const VERSION = '5.50.1';
 export const PUBLIC_VERSION = '5';

From bd5480b9d08ef0022c03345b914694aa73e30d33 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Tue, 10 Feb 2026 15:45:34 +0100
Subject: [PATCH 140/142] fix: reduce if block nesting (#17662)

* fix: reduce if block nesting

This reduces if block nesting similar to how we did it in #15250 (which got lost during the `await` feature introduction): If the if expression doesn't contain an await expression or is not dependent on a blocker that is not already resolved, then we can avoid creating a separate `$.if()` statement. The one trade-off is that we'll do re-invocations  for all the conditions leading up to the condition that matches. Therefore non-simple if expressions are wrapper in `$.derived` to avoid excessive recomputations.

closes #17659 (~320 markers in prod mode possible now; less in dev because of our "wrap this component with devtime info" method)
helps with #15200

* tweak

* feedback
---
 .changeset/wild-dolls-hang.md                 |   5 +
 .../phases/2-analyze/visitors/IfBlock.js      |  19 ++
 .../3-transform/client/visitors/Fragment.js   |   6 +-
 .../3-transform/client/visitors/IfBlock.js    |  85 +++++---
 .../3-transform/server/visitors/IfBlock.js    |  34 ++-
 packages/svelte/src/compiler/phases/nodes.js  |  13 ++
 .../svelte/src/compiler/types/template.d.ts   |   2 +
 .../src/internal/client/dom/blocks/if.js      |  36 ++--
 .../src/internal/client/dom/hydration.js      |   7 +-
 .../samples/async-if-nested/_config.js        |  12 ++
 .../samples/async-if-nested/main.svelte       |  21 ++
 .../async-state-new-branch/Child.svelte       |   7 +
 .../samples/async-state-new-branch/_config.js |  47 ++++
 .../async-state-new-branch/main.svelte        |  28 +++
 .../samples/async-if-chain/_config.js         |   3 +
 .../_expected/client/index.svelte.js          | 201 ++++++++++++++++++
 .../_expected/server/index.svelte.js          | 110 ++++++++++
 .../samples/async-if-chain/index.svelte       |  59 +++++
 18 files changed, 647 insertions(+), 48 deletions(-)
 create mode 100644 .changeset/wild-dolls-hang.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-if-nested/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-if-nested/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-state-new-branch/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-state-new-branch/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-state-new-branch/main.svelte
 create mode 100644 packages/svelte/tests/snapshot/samples/async-if-chain/_config.js
 create mode 100644 packages/svelte/tests/snapshot/samples/async-if-chain/_expected/client/index.svelte.js
 create mode 100644 packages/svelte/tests/snapshot/samples/async-if-chain/_expected/server/index.svelte.js
 create mode 100644 packages/svelte/tests/snapshot/samples/async-if-chain/index.svelte

diff --git a/.changeset/wild-dolls-hang.md b/.changeset/wild-dolls-hang.md
new file mode 100644
index 0000000000..a7b3436d69
--- /dev/null
+++ b/.changeset/wild-dolls-hang.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: reduce if block nesting
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/IfBlock.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/IfBlock.js
index dcdae3587f..64855abdaf 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/IfBlock.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/IfBlock.js
@@ -24,4 +24,23 @@ export function IfBlock(node, context) {
 
 	context.visit(node.consequent);
 	if (node.alternate) context.visit(node.alternate);
+
+	// Check if we can flatten branches
+	const alt = node.alternate;
+
+	if (alt && alt.nodes.length === 1 && alt.nodes[0].type === 'IfBlock' && alt.nodes[0].elseif) {
+		const elseif = alt.nodes[0];
+
+		// Don't flatten if this else-if has an await expression or new blockers
+		// TODO would be nice to check the await expression itself to see if it's awaiting the same thing as a previous if expression
+		if (
+			!elseif.metadata.expression.has_await &&
+			!elseif.metadata.expression.has_more_blockers_than(node.metadata.expression)
+		) {
+			// Roll the existing flattened branches (if any) into this one, then delete those of the else-if block
+			// to avoid processing them multiple times as we walk down the chain during code transformation.
+			node.metadata.flattened = [elseif, ...(elseif.metadata.flattened ?? [])];
+			elseif.metadata.flattened = undefined;
+		}
+	}
 }
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 00b0cfaa2e..be919d380c 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
@@ -47,7 +47,11 @@ export function Fragment(node, context) {
 	const is_single_element = trimmed.length === 1 && trimmed[0].type === 'RegularElement';
 	const is_single_child_not_needing_template =
 		trimmed.length === 1 &&
-		(trimmed[0].type === 'SvelteFragment' || trimmed[0].type === 'TitleElement');
+		(trimmed[0].type === 'SvelteFragment' ||
+			trimmed[0].type === 'TitleElement' ||
+			(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[]} */
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 c0e66635df..0d31c42d11 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
@@ -1,4 +1,4 @@
-/** @import { BlockStatement, Expression } from 'estree' */
+/** @import { BlockStatement, Expression, IfStatement, Statement } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types' */
 import * as b from '#compiler/builders';
@@ -10,40 +10,75 @@ import { build_expression, add_svelte_meta } from './shared/utils.js';
  */
 export function IfBlock(node, context) {
 	context.state.template.push_comment();
+
+	/** @type {Statement[]} */
 	const statements = [];
 
-	const consequent = /** @type {BlockStatement} */ (context.visit(node.consequent));
-	const consequent_id = b.id(context.state.scope.generate('consequent'));
+	const has_await = node.metadata.expression.has_await;
+	const has_blockers = node.metadata.expression.has_blockers();
+	const expression = build_expression(context, node.test, node.metadata.expression);
+
+	// Build the if/else-if/else chain
+	let index = 0;
+	/** @type {IfStatement | undefined} */
+	let first_if;
+	/** @type {IfStatement | undefined} */
+	let last_if;
+	/** @type {AST.IfBlock | undefined} */
+	let last_alt;
 
-	statements.push(b.var(consequent_id, b.arrow([b.id('$$anchor')], consequent)));
+	for (const branch of [node, ...(node.metadata.flattened ?? [])]) {
+		const consequent = /** @type {BlockStatement} */ (context.visit(branch.consequent));
+		const consequent_id = b.id(context.state.scope.generate('consequent'));
+		statements.push(b.var(consequent_id, b.arrow([b.id('$$anchor')], consequent)));
 
-	let alternate_id;
+		// Build the test expression for this branch
+		/** @type {Expression} */
+		let test;
 
-	if (node.alternate) {
-		const alternate = /** @type {BlockStatement} */ (context.visit(node.alternate));
-		alternate_id = b.id(context.state.scope.generate('alternate'));
-		statements.push(b.var(alternate_id, b.arrow([b.id('$$anchor')], alternate)));
+		if (branch.metadata.expression.has_await) {
+			// Top-level condition with await: already resolved by $.async wrapper
+			test = b.call('$.get', b.id('$$condition'));
+		} else {
+			const expression = build_expression(context, branch.test, branch.metadata.expression);
+
+			if (branch.metadata.expression.has_call) {
+				const derived_id = b.id(context.state.scope.generate('d'));
+				statements.push(b.var(derived_id, b.call('$.derived', b.arrow([], expression))));
+				test = b.call('$.get', derived_id);
+			} else {
+				test = expression;
+			}
+		}
+
+		const render_call = b.stmt(b.call('$$render', consequent_id, index > 0 && b.literal(index)));
+		const new_if = b.if(test, render_call);
+
+		if (last_if) {
+			last_if.alternate = new_if;
+		} else {
+			first_if = new_if;
+		}
+
+		last_alt = branch;
+		last_if = new_if;
+		index++;
 	}
 
-	const has_await = node.metadata.expression.has_await;
-	const has_blockers = node.metadata.expression.has_blockers();
+	// Handle final alternate (else branch, remaining async chain, or nothing)
+	if (last_if && last_alt?.alternate) {
+		const alternate = /** @type {BlockStatement} */ (context.visit(last_alt.alternate));
+		const alternate_id = b.id(context.state.scope.generate('alternate'));
+		statements.push(b.var(alternate_id, b.arrow([b.id('$$anchor')], alternate)));
 
-	const expression = build_expression(context, node.test, node.metadata.expression);
-	const test = has_await ? b.call('$.get', b.id('$$condition')) : expression;
+		last_if.alternate = b.stmt(b.call('$$render', alternate_id, b.literal(false)));
+	}
 
+	// Build $.if() arguments
 	/** @type {Expression[]} */
 	const args = [
 		context.state.node,
-		b.arrow(
-			[b.id('$$render')],
-			b.block([
-				b.if(
-					test,
-					b.stmt(b.call('$$render', consequent_id)),
-					alternate_id && b.stmt(b.call('$$render', alternate_id, b.literal(false)))
-				)
-			])
-		)
+		b.arrow([b.id('$$render')], first_if ? b.block([first_if]) : b.block([]))
 	];
 
 	if (node.elseif) {
@@ -67,7 +102,9 @@ export function IfBlock(node, context) {
 		//
 		// ...even though they're logically equivalent. In the first case, the
 		// transition will only play when `y` changes, but in the second it
-		// should play when `x` or `y` change — both are considered 'local'
+		// should play when `x` or `y` change — both are considered 'local'.
+		// This could also be a non-flattened elseif (because it has an async expression).
+		// In both cases mark as elseif so the runtime uses EFFECT_TRANSPARENT for transitions.
 		args.push(b.true);
 	}
 
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 06b1b1e966..e3f5f88705 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
@@ -1,4 +1,4 @@
-/** @import { BlockStatement, Expression, Statement } from 'estree' */
+/** @import { BlockStatement, Expression, IfStatement, Statement } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types.js' */
 import * as b from '#compiler/builders';
@@ -9,23 +9,37 @@ import { block_close, block_open, block_open_else, create_child_block } from './
  * @param {ComponentContext} context
  */
 export function IfBlock(node, context) {
-	const test = /** @type {Expression} */ (context.visit(node.test));
 	const consequent = /** @type {BlockStatement} */ (context.visit(node.consequent));
+	consequent.body.unshift(b.stmt(b.call(b.id('$$renderer.push'), block_open)));
 
-	const alternate = node.alternate
-		? /** @type {BlockStatement} */ (context.visit(node.alternate))
-		: b.block([]);
+	/** @type {IfStatement} */
+	let if_statement = b.if(/** @type {Expression} */ (context.visit(node.test)), consequent);
 
-	consequent.body.unshift(b.stmt(b.call(b.id('$$renderer.push'), block_open)));
+	let index = 1;
+	let current_if = if_statement;
+	let alt = node.alternate;
+
+	// Walk the else-if chain, flattening branches
+	for (const elseif of node.metadata.flattened ?? []) {
+		const branch = /** @type {BlockStatement} */ (context.visit(elseif.consequent));
+		branch.body.unshift(b.stmt(b.call(b.id('$$renderer.push'), b.literal(`<!--[${index++}-->`))));
+
+		current_if = current_if.alternate = b.if(
+			/** @type {Expression} */ (context.visit(elseif.test)),
+			branch
+		);
+		alt = elseif.alternate;
+	}
 
-	alternate.body.unshift(b.stmt(b.call(b.id('$$renderer.push'), block_open_else)));
+	// Handle final else (or remaining async chain)
+	const final_alternate = alt ? /** @type {BlockStatement} */ (context.visit(alt)) : b.block([]);
 
-	/** @type {Statement} */
-	let statement = b.if(test, consequent, alternate);
+	final_alternate.body.unshift(b.stmt(b.call(b.id('$$renderer.push'), block_open_else)));
+	current_if.alternate = final_alternate;
 
 	context.state.template.push(
 		...create_child_block(
-			[statement],
+			[if_statement],
 			node.metadata.expression.blockers(),
 			node.metadata.expression.has_await
 		),
diff --git a/packages/svelte/src/compiler/phases/nodes.js b/packages/svelte/src/compiler/phases/nodes.js
index f302603409..2e54f333a8 100644
--- a/packages/svelte/src/compiler/phases/nodes.js
+++ b/packages/svelte/src/compiler/phases/nodes.js
@@ -118,6 +118,19 @@ export class ExpressionMetadata {
 		return this.#get_blockers().size > 0;
 	}
 
+	/**
+	 * @param {ExpressionMetadata} other
+	 */
+	has_more_blockers_than(other) {
+		for (const blocker of this.#get_blockers()) {
+			if (!other.#get_blockers().has(blocker)) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+
 	is_async() {
 		return this.has_await || this.#get_blockers().size > 0;
 	}
diff --git a/packages/svelte/src/compiler/types/template.d.ts b/packages/svelte/src/compiler/types/template.d.ts
index b924406d0f..d44a31349a 100644
--- a/packages/svelte/src/compiler/types/template.d.ts
+++ b/packages/svelte/src/compiler/types/template.d.ts
@@ -483,6 +483,8 @@ export namespace AST {
 		alternate: Fragment | null;
 		/** @internal */
 		metadata: {
+			/** List of else-if blocks that can be flattened into this if block */
+			flattened?: IfBlock[];
 			expression: ExpressionMetadata;
 		};
 	}
diff --git a/packages/svelte/src/internal/client/dom/blocks/if.js b/packages/svelte/src/internal/client/dom/blocks/if.js
index 7fa5ca464d..f2b1cf80a5 100644
--- a/packages/svelte/src/internal/client/dom/blocks/if.js
+++ b/packages/svelte/src/internal/client/dom/blocks/if.js
@@ -9,14 +9,12 @@ import {
 	set_hydrating
 } from '../hydration.js';
 import { block } from '../../reactivity/effects.js';
-import { HYDRATION_START_ELSE } from '../../../../constants.js';
 import { BranchManager } from './branches.js';
-
-// TODO reinstate https://github.com/sveltejs/svelte/pull/15250
+import { HYDRATION_START, HYDRATION_START_ELSE } from '../../../../constants.js';
 
 /**
  * @param {TemplateNode} node
- * @param {(branch: (fn: (anchor: Node) => void, flag?: boolean) => void) => void} fn
+ * @param {(branch: (fn: (anchor: Node) => void, key?: number | false) => void) => void} fn
  * @param {boolean} [elseif] True if this is an `{:else if ...}` block rather than an `{#if ...}`, as that affects which transitions are considered 'local'
  * @returns {void}
  */
@@ -29,14 +27,28 @@ export function if_block(node, fn, elseif = false) {
 	var flags = elseif ? EFFECT_TRANSPARENT : 0;
 
 	/**
-	 * @param {boolean} condition,
+	 * @param {number | false} key
 	 * @param {null | ((anchor: Node) => void)} fn
 	 */
-	function update_branch(condition, fn) {
+	function update_branch(key, fn) {
 		if (hydrating) {
-			const is_else = read_hydration_instruction(node) === HYDRATION_START_ELSE;
+			const data = read_hydration_instruction(node);
+
+			/**
+			 * @type {number | false}
+			 * "[" = branch 0, "[1" = branch 1, "[2" = branch 2, ..., "[!" = else (false)
+			 */
+			var hydrated_key;
+
+			if (data === HYDRATION_START) {
+				hydrated_key = 0;
+			} else if (data === HYDRATION_START_ELSE) {
+				hydrated_key = false;
+			} else {
+				hydrated_key = parseInt(data.substring(1)); // "[1", "[2", etc.
+			}
 
-			if (condition === is_else) {
+			if (key !== hydrated_key) {
 				// Hydration mismatch: remove everything inside the anchor and start fresh.
 				// This could happen with `{#if browser}...{/if}`, for example
 				var anchor = skip_nodes();
@@ -45,22 +57,22 @@ export function if_block(node, fn, elseif = false) {
 				branches.anchor = anchor;
 
 				set_hydrating(false);
-				branches.ensure(condition, fn);
+				branches.ensure(key, fn);
 				set_hydrating(true);
 
 				return;
 			}
 		}
 
-		branches.ensure(condition, fn);
+		branches.ensure(key, fn);
 	}
 
 	block(() => {
 		var has_branch = false;
 
-		fn((fn, flag = true) => {
+		fn((fn, key = 0) => {
 			has_branch = true;
-			update_branch(flag, fn);
+			update_branch(key, fn);
 		});
 
 		if (!has_branch) {
diff --git a/packages/svelte/src/internal/client/dom/hydration.js b/packages/svelte/src/internal/client/dom/hydration.js
index 7a9ef33d1b..83833f493d 100644
--- a/packages/svelte/src/internal/client/dom/hydration.js
+++ b/packages/svelte/src/internal/client/dom/hydration.js
@@ -95,7 +95,12 @@ export function skip_nodes(remove = true) {
 			if (data === HYDRATION_END) {
 				if (depth === 0) return node;
 				depth -= 1;
-			} else if (data === HYDRATION_START || data === HYDRATION_START_ELSE) {
+			} else if (
+				data === HYDRATION_START ||
+				data === HYDRATION_START_ELSE ||
+				// "[1", "[2", etc. for if blocks
+				(data[0] === '[' && !isNaN(Number(data.slice(1))))
+			) {
 				depth += 1;
 			}
 		}
diff --git a/packages/svelte/tests/runtime-runes/samples/async-if-nested/_config.js b/packages/svelte/tests/runtime-runes/samples/async-if-nested/_config.js
new file mode 100644
index 0000000000..49cae28cc4
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-if-nested/_config.js
@@ -0,0 +1,12 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['async-server', 'hydrate', 'client'],
+	ssrHtml: `bar blocking`,
+
+	async test({ assert, target }) {
+		await tick();
+		assert.htmlEqual(target.innerHTML, 'bar blocking');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-if-nested/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-if-nested/main.svelte
new file mode 100644
index 0000000000..cfb17e3c76
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-if-nested/main.svelte
@@ -0,0 +1,21 @@
+<script>
+  let foo = $state(false);
+  let blocking = $derived(await foo);
+  let bar = Promise.resolve(true);
+</script>
+
+{#if foo}
+  foo
+{:else if await bar}
+  bar
+{:else}
+  else
+{/if}
+
+{#if foo}
+  foo
+{:else if !blocking}
+  blocking
+{:else}
+  else
+{/if}
diff --git a/packages/svelte/tests/runtime-runes/samples/async-state-new-branch/Child.svelte b/packages/svelte/tests/runtime-runes/samples/async-state-new-branch/Child.svelte
new file mode 100644
index 0000000000..6b765526c8
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-state-new-branch/Child.svelte
@@ -0,0 +1,7 @@
+<script>
+	let { x } = $props();
+	console.log(x);
+	$effect(() => console.log('$effect: '+ x))
+</script>
+
+{x}
diff --git a/packages/svelte/tests/runtime-runes/samples/async-state-new-branch/_config.js b/packages/svelte/tests/runtime-runes/samples/async-state-new-branch/_config.js
new file mode 100644
index 0000000000..f2091eb6ab
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-state-new-branch/_config.js
@@ -0,0 +1,47 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	skip: true, // this fails on main, too; skip for now
+	async test({ assert, target, logs }) {
+		const [x, y, resolve] = target.querySelectorAll('button');
+
+		x.click();
+		await tick();
+		assert.deepEqual(logs, ['universe']);
+
+		y.click();
+		await tick();
+		assert.deepEqual(logs, ['universe', 'world', '$effect: world']);
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+			<button>x</button>
+			<button>y++</button>
+			<button>resolve</button>
+			world
+		`
+		);
+
+		resolve.click();
+		await tick();
+		assert.deepEqual(logs, [
+			'universe',
+			'world',
+			'$effect: world',
+			'$effect: universe',
+			'$effect: universe'
+		]);
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+			<button>x</button>
+			<button>y++</button>
+			<button>resolve</button>
+			universe
+			universe
+			universe
+		`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-state-new-branch/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-state-new-branch/main.svelte
new file mode 100644
index 0000000000..8edc718de2
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-state-new-branch/main.svelte
@@ -0,0 +1,28 @@
+<script>
+	import Child from './Child.svelte';
+
+	let x = $state('world');
+	let y = $state(0);
+	let deferred = [];
+
+	function delay(s) {
+		const d = Promise.withResolvers();
+		deferred.push(() => d.resolve(s))
+		return d.promise;
+	}
+</script>
+
+<button onclick={() => x = 'universe'}>x</button>
+
+<button onclick={() => y++}>y++</button>
+
+<button onclick={() => deferred.shift()()}>resolve</button>
+
+{#if x === 'universe'}
+	{await delay(x)}
+	<Child {x} />
+{/if}
+
+{#if y > 0}
+	<Child {x} />
+{/if}
diff --git a/packages/svelte/tests/snapshot/samples/async-if-chain/_config.js b/packages/svelte/tests/snapshot/samples/async-if-chain/_config.js
new file mode 100644
index 0000000000..2e30bbeb16
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/async-if-chain/_config.js
@@ -0,0 +1,3 @@
+import { test } from '../../test';
+
+export default test({ compileOptions: { experimental: { async: true } } });
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
new file mode 100644
index 0000000000..b55e3010b8
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/async-if-chain/_expected/client/index.svelte.js
@@ -0,0 +1,201 @@
+import 'svelte/internal/disclose-version';
+import 'svelte/internal/flags/async';
+import * as $ from 'svelte/internal/client';
+
+var root = $.from_html(`<!> <!> <!> <!> <!>`, 1);
+
+export default function Async_if_chain($$anchor) {
+	function complex1() {
+		return 1;
+	}
+
+	let foo = true;
+	var blocking;
+	var $$promises = $.run([async () => blocking = await $.async_derived(() => foo)]);
+	var fragment = root();
+	var node = $.first_child(fragment);
+
+	$.async(node, [$$promises[0]], void 0, (node) => {
+		var consequent = ($$anchor) => {
+			var text = $.text('foo');
+
+			$.append($$anchor, text);
+		};
+
+		var consequent_1 = ($$anchor) => {
+			var text_1 = $.text('bar');
+
+			$.append($$anchor, text_1);
+		};
+
+		var alternate = ($$anchor) => {
+			var text_2 = $.text('else');
+
+			$.append($$anchor, text_2);
+		};
+
+		$.if(node, ($$render) => {
+			if (foo) $$render(consequent); else if (bar) $$render(consequent_1, 1); else $$render(alternate, false);
+		});
+	});
+
+	var node_1 = $.sibling(node, 2);
+
+	$.async(node_1, [$$promises[0]], [() => foo], (node_1, $$condition) => {
+		var consequent_2 = ($$anchor) => {
+			var text_3 = $.text('foo');
+
+			$.append($$anchor, text_3);
+		};
+
+		var consequent_3 = ($$anchor) => {
+			var text_4 = $.text('bar');
+
+			$.append($$anchor, text_4);
+		};
+
+		var alternate_2 = ($$anchor) => {
+			var fragment_1 = $.comment();
+			var node_2 = $.first_child(fragment_1);
+
+			$.async(node_2, [], [() => baz], (node_2, $$condition) => {
+				var consequent_4 = ($$anchor) => {
+					var text_5 = $.text('baz');
+
+					$.append($$anchor, text_5);
+				};
+
+				var alternate_1 = ($$anchor) => {
+					var text_6 = $.text('else');
+
+					$.append($$anchor, text_6);
+				};
+
+				$.if(
+					node_2,
+					($$render) => {
+						if ($.get($$condition)) $$render(consequent_4); else $$render(alternate_1, false);
+					},
+					true
+				);
+			});
+
+			$.append($$anchor, fragment_1);
+		};
+
+		$.if(node_1, ($$render) => {
+			if ($.get($$condition)) $$render(consequent_2); else if (bar) $$render(consequent_3, 1); else $$render(alternate_2, false);
+		});
+	});
+
+	var node_3 = $.sibling(node_1, 2);
+
+	$.async(node_3, [$$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(
+					node_4,
+					($$render) => {
+						if ($.get($$condition)) $$render(consequent_7); else $$render(alternate_3, false);
+					},
+					true
+				);
+			});
+
+			$.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, false);
+		});
+	});
+
+	var node_5 = $.sibling(node_3, 2);
+
+	{
+		var consequent_8 = ($$anchor) => {
+			var text_11 = $.text('foo');
+
+			$.append($$anchor, text_11);
+		};
+
+		var consequent_9 = ($$anchor) => {
+			var text_12 = $.text('bar');
+
+			$.append($$anchor, text_12);
+		};
+
+		var consequent_10 = ($$anchor) => {
+			var text_13 = $.text('baz');
+
+			$.append($$anchor, text_13);
+		};
+
+		var d = $.derived(() => complex1() * complex2 > 100);
+
+		var alternate_5 = ($$anchor) => {
+			var text_14 = $.text('else');
+
+			$.append($$anchor, text_14);
+		};
+
+		$.if(node_5, ($$render) => {
+			if (simple1) $$render(consequent_8); else if (simple2 > 10) $$render(consequent_9, 1); else if ($.get(d)) $$render(consequent_10, 2); else $$render(alternate_5, false);
+		});
+	}
+
+	var node_6 = $.sibling(node_5, 2);
+
+	$.async(node_6, [$$promises[0]], void 0, (node_6) => {
+		var consequent_11 = ($$anchor) => {
+			var text_15 = $.text('foo');
+
+			$.append($$anchor, text_15);
+		};
+
+		var consequent_12 = ($$anchor) => {
+			var text_16 = $.text('bar');
+
+			$.append($$anchor, text_16);
+		};
+
+		var alternate_6 = ($$anchor) => {
+			var text_17 = $.text('else');
+
+			$.append($$anchor, text_17);
+		};
+
+		$.if(node_6, ($$render) => {
+			if ($.get(blocking) > 10) $$render(consequent_11); else if ($.get(blocking) > 5) $$render(consequent_12, 1); else $$render(alternate_6, false);
+		});
+	});
+
+	$.append($$anchor, fragment);
+}
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/async-if-chain/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-if-chain/_expected/server/index.svelte.js
new file mode 100644
index 0000000000..91315edb94
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/async-if-chain/_expected/server/index.svelte.js
@@ -0,0 +1,110 @@
+import 'svelte/internal/flags/async';
+import * as $ from 'svelte/internal/server';
+
+export default function Async_if_chain($$renderer) {
+	function complex1() {
+		return 1;
+	}
+
+	let foo = true;
+	var blocking;
+	var $$promises = $$renderer.run([async () => blocking = await foo]);
+
+	$$renderer.async_block([$$promises[0]], ($$renderer) => {
+		if (foo) {
+			$$renderer.push('<!--[-->');
+			$$renderer.push(`foo`);
+		} else if (bar) {
+			$$renderer.push('<!--[1-->');
+			$$renderer.push(`bar`);
+		} else {
+			$$renderer.push('<!--[!-->');
+			$$renderer.push(`else`);
+		}
+	});
+
+	$$renderer.push(`<!--]--> `);
+
+	$$renderer.async_block([$$promises[0]], async ($$renderer) => {
+		if ((await $.save(foo))()) {
+			$$renderer.push('<!--[-->');
+			$$renderer.push(`foo`);
+		} else if (bar) {
+			$$renderer.push('<!--[1-->');
+			$$renderer.push(`bar`);
+		} else {
+			$$renderer.push('<!--[!-->');
+
+			$$renderer.child_block(async ($$renderer) => {
+				if ((await $.save(baz))()) {
+					$$renderer.push('<!--[-->');
+					$$renderer.push(`baz`);
+				} else {
+					$$renderer.push('<!--[!-->');
+					$$renderer.push(`else`);
+				}
+			});
+
+			$$renderer.push(`<!--]-->`);
+		}
+	});
+
+	$$renderer.push(`<!--]--> `);
+
+	$$renderer.async_block([$$promises[0]], async ($$renderer) => {
+		if ((await $.save(foo))() > 10) {
+			$$renderer.push('<!--[-->');
+			$$renderer.push(`foo`);
+		} else if (bar) {
+			$$renderer.push('<!--[1-->');
+			$$renderer.push(`bar`);
+		} else {
+			$$renderer.push('<!--[!-->');
+
+			$$renderer.async_block([$$promises[0]], async ($$renderer) => {
+				if ((await $.save(foo))() > 5) {
+					$$renderer.push('<!--[-->');
+					$$renderer.push(`baz`);
+				} else {
+					$$renderer.push('<!--[!-->');
+					$$renderer.push(`else`);
+				}
+			});
+
+			$$renderer.push(`<!--]-->`);
+		}
+	});
+
+	$$renderer.push(`<!--]--> `);
+
+	if (simple1) {
+		$$renderer.push('<!--[-->');
+		$$renderer.push(`foo`);
+	} else if (simple2 > 10) {
+		$$renderer.push('<!--[1-->');
+		$$renderer.push(`bar`);
+	} else if (complex1() * complex2 > 100) {
+		$$renderer.push('<!--[2-->');
+		$$renderer.push(`baz`);
+	} else {
+		$$renderer.push('<!--[!-->');
+		$$renderer.push(`else`);
+	}
+
+	$$renderer.push(`<!--]--> `);
+
+	$$renderer.async_block([$$promises[0]], ($$renderer) => {
+		if (blocking > 10) {
+			$$renderer.push('<!--[-->');
+			$$renderer.push(`foo`);
+		} else if (blocking > 5) {
+			$$renderer.push('<!--[1-->');
+			$$renderer.push(`bar`);
+		} else {
+			$$renderer.push('<!--[!-->');
+			$$renderer.push(`else`);
+		}
+	});
+
+	$$renderer.push(`<!--]-->`);
+}
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/async-if-chain/index.svelte b/packages/svelte/tests/snapshot/samples/async-if-chain/index.svelte
new file mode 100644
index 0000000000..1f216af0b0
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/async-if-chain/index.svelte
@@ -0,0 +1,59 @@
+<script>
+  function complex1() {
+    return 1;
+  }
+
+  let foo = $state(true);
+  let blocking = $derived(await foo);
+</script>
+
+<!-- simple chain - should have no nested $.if() -->
+{#if foo}
+  foo
+{:else if bar}
+  bar
+{:else}
+  else
+{/if}
+
+<!-- simple chain with await expressions - should have $.if() at each await expression -->
+{#if await foo}
+  foo
+{:else if bar}
+  bar
+{:else if await baz}
+  baz
+{:else}
+  else
+{/if}
+
+<!-- simple chain with await expressions #2 - should have $.if() at each await expression (ideally we can detect that await foo is unnecessary to await multiple times and this is one $.if()) -->
+{#if await foo > 10}
+  foo
+{:else if bar}
+  bar
+{:else if await foo > 5}
+  baz
+{:else}
+  else
+{/if}
+
+<!-- simple chain with some expressions that cause a $.derived - should be one $.if() -->
+{#if simple1}
+  foo
+{:else if simple2 > 10}
+  bar
+{:else if complex1() * complex2 > 100}
+  baz
+{:else}
+  else
+{/if}
+
+<!-- simple chain with blocking expressions - should be one $.if() -->
+{#if blocking > 10}
+  foo
+{:else if blocking > 5}
+  bar
+{:else}
+  else
+{/if}

From 15fe6b85c09ab543f603f64121fb86df9dbb02f7 Mon Sep 17 00:00:00 2001
From: Mohit Kourav <mohitdas852@gmail.com>
Date: Tue, 10 Feb 2026 20:36:26 +0530
Subject: [PATCH 141/142] feat: add warning when media.play() fails in
 bind:paused (#17656)

* feat: add warning when media.play() fails in bind:paused

* chore: fix formatting in media.js

* chore: use Rich Harris's suggested approach for media.play() error handling

* Apply suggestion from @Rich-Harris

---------

Co-authored-by: Rich Harris <hello@rich-harris.dev>
---
 .changeset/orange-wasps-visit.md                             | 5 +++++
 .../src/internal/client/dom/elements/bindings/media.js       | 3 ++-
 2 files changed, 7 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/orange-wasps-visit.md

diff --git a/.changeset/orange-wasps-visit.md b/.changeset/orange-wasps-visit.md
new file mode 100644
index 0000000000..972ff636b8
--- /dev/null
+++ b/.changeset/orange-wasps-visit.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: don't swallow `DOMException` when `media.play()` fails in `bind:paused`
diff --git a/packages/svelte/src/internal/client/dom/elements/bindings/media.js b/packages/svelte/src/internal/client/dom/elements/bindings/media.js
index f96ee05989..87da950375 100644
--- a/packages/svelte/src/internal/client/dom/elements/bindings/media.js
+++ b/packages/svelte/src/internal/client/dom/elements/bindings/media.js
@@ -175,8 +175,9 @@ export function bind_paused(media, get, set = get) {
 			if (paused) {
 				media.pause();
 			} else {
-				media.play().catch(() => {
+				media.play().catch((error) => {
 					set((paused = true));
+					throw error;
 				});
 			}
 		}

From e3d7f3986f8b0117ce6358e1c6e54f5d5e38d3e8 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Tue, 10 Feb 2026 15:23:29 -0500
Subject: [PATCH 142/142] chore: update ESLint to v10 (#17670)

* chore: update ESLint to v10

Update eslint and related plugins/configs. Bump CI lint job to Node 24
(ESLint 10 requires ^20.19.0 || ^22.13.0 || >=24). Replace removed
Linter.FlatConfig type with Linter.Config.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: address new `no-useless-assignment` violations from ESLint 10

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* dedupe

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
---
 .github/workflows/ci.yml                      |   2 +-
 eslint.config.js                              |   2 +-
 package.json                                  |  18 +-
 .../phases/1-parse/utils/fuzzymatch.js        |   3 +-
 .../server/visitors/shared/element.js         |   2 +-
 packages/svelte/src/internal/client/proxy.js  |   2 +-
 .../src/internal/client/reactivity/sources.js |   1 +
 pnpm-lock.yaml                                | 546 +++++++++---------
 8 files changed, 294 insertions(+), 282 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8dcf1e45dc..23d814d527 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -86,7 +86,7 @@ jobs:
       - uses: pnpm/action-setup@v4
       - uses: actions/setup-node@v6
         with:
-          node-version: 18
+          node-version: 24
           cache: pnpm
       - name: install
         run: pnpm install --frozen-lockfile
diff --git a/eslint.config.js b/eslint.config.js
index 04d9294394..0e8382427b 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -33,7 +33,7 @@ const no_compiler_imports = {
 	}
 };
 
-/** @type {import('eslint').Linter.FlatConfig[]} */
+/** @type {import('eslint').Linter.Config[]} */
 export default [
 	...svelte_config,
 	{
diff --git a/package.json b/package.json
index e7faf26c13..b305ce9cd1 100644
--- a/package.json
+++ b/package.json
@@ -27,22 +27,30 @@
   },
   "devDependencies": {
     "@changesets/cli": "^2.29.8",
-    "@sveltejs/eslint-config": "^8.3.3",
+    "@sveltejs/eslint-config": "^8.3.5",
     "@svitejs/changesets-changelog-github-compact": "^1.1.0",
     "@types/node": "^20.11.5",
     "@types/picomatch": "^4.0.2",
     "@vitest/coverage-v8": "^2.1.9",
-    "eslint": "^9.9.1",
-    "eslint-plugin-lube": "^0.4.3",
-    "eslint-plugin-svelte": "^3.11.0",
+    "@eslint/js": "^10.0.0",
+    "eslint": "^10.0.0",
+    "eslint-plugin-lube": "^0.5.1",
+    "eslint-plugin-svelte": "^3.15.0",
     "jsdom": "25.0.1",
     "playwright": "^1.58.0",
     "prettier": "^3.2.4",
     "prettier-plugin-svelte": "^3.4.0",
     "svelte": "workspace:^",
     "typescript": "^5.5.4",
-    "typescript-eslint": "^8.48.1",
+    "typescript-eslint": "^8.55.0",
     "v8-natives": "^1.2.5",
     "vitest": "^2.1.9"
+  },
+  "pnpm": {
+    "peerDependencyRules": {
+      "allowedVersions": {
+        "eslint": "10"
+      }
+    }
   }
 }
diff --git a/packages/svelte/src/compiler/phases/1-parse/utils/fuzzymatch.js b/packages/svelte/src/compiler/phases/1-parse/utils/fuzzymatch.js
index 28b314cdd5..c8cf7f14ff 100644
--- a/packages/svelte/src/compiler/phases/1-parse/utils/fuzzymatch.js
+++ b/packages/svelte/src/compiler/phases/1-parse/utils/fuzzymatch.js
@@ -46,10 +46,11 @@ function levenshtein(str1, str2) {
 	/** @type {number[]} */
 	const current = [];
 	let prev = 0;
-	let value = 0;
 
 	for (let i = 0; i <= str2.length; i++) {
 		for (let j = 0; j <= str1.length; j++) {
+			let value;
+
 			if (i && j) {
 				if (str1.charAt(j - 1) === str2.charAt(i - 1)) {
 					value = prev;
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 f4f491c056..5bc8fb15b5 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
@@ -538,7 +538,7 @@ function build_attr_style(style_directives, expression, context, transform) {
 				name = name.toLowerCase();
 			}
 
-			const property = b.init(directive.name, expression);
+			const property = b.init(name, expression);
 			if (directive.modifiers.includes('important')) {
 				important_properties.push(property);
 			} else {
diff --git a/packages/svelte/src/internal/client/proxy.js b/packages/svelte/src/internal/client/proxy.js
index c8802e2672..51333e597f 100644
--- a/packages/svelte/src/internal/client/proxy.js
+++ b/packages/svelte/src/internal/client/proxy.js
@@ -126,7 +126,7 @@ export function proxy(value) {
 			}
 			var s = sources.get(prop);
 			if (s === undefined) {
-				s = with_parent(() => {
+				with_parent(() => {
 					var s = source(descriptor.value, stack);
 					sources.set(prop, s);
 					if (DEV && typeof prop === 'string') {
diff --git a/packages/svelte/src/internal/client/reactivity/sources.js b/packages/svelte/src/internal/client/reactivity/sources.js
index 3ef08588c4..52dd4ebe41 100644
--- a/packages/svelte/src/internal/client/reactivity/sources.js
+++ b/packages/svelte/src/internal/client/reactivity/sources.js
@@ -302,6 +302,7 @@ export function update_pre(source, d = 1) {
 	var value = get(source);
 
 	// @ts-expect-error
+	// eslint-disable-next-line no-useless-assignment -- `++`/`--` used for return value, not side effect on `value`
 	return set(source, d === 1 ? ++value : --value);
 }
 
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 6d3e66825c..48c2a52cc5 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -11,9 +11,12 @@ importers:
       '@changesets/cli':
         specifier: ^2.29.8
         version: 2.29.8(@types/node@20.19.17)
+      '@eslint/js':
+        specifier: ^10.0.0
+        version: 10.0.1(eslint@10.0.0)
       '@sveltejs/eslint-config':
-        specifier: ^8.3.3
-        version: 8.3.3(@stylistic/eslint-plugin-js@1.8.0(eslint@9.9.1))(eslint-config-prettier@9.1.0(eslint@9.9.1))(eslint-plugin-n@17.16.1(eslint@9.9.1)(typescript@5.5.4))(eslint-plugin-svelte@3.11.0(eslint@9.9.1)(svelte@packages+svelte))(eslint@9.9.1)(typescript-eslint@8.48.1(eslint@9.9.1)(typescript@5.5.4))(typescript@5.5.4)
+        specifier: ^8.3.5
+        version: 8.3.5(@stylistic/eslint-plugin-js@1.8.0(eslint@10.0.0))(eslint-config-prettier@9.1.0(eslint@10.0.0))(eslint-plugin-n@17.16.1(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@8.55.0(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
@@ -27,14 +30,14 @@ importers:
         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))
       eslint:
-        specifier: ^9.9.1
-        version: 9.9.1
+        specifier: ^10.0.0
+        version: 10.0.0
       eslint-plugin-lube:
-        specifier: ^0.4.3
-        version: 0.4.3
+        specifier: ^0.5.1
+        version: 0.5.1(eslint@10.0.0)
       eslint-plugin-svelte:
-        specifier: ^3.11.0
-        version: 3.11.0(eslint@9.9.1)(svelte@packages+svelte)
+        specifier: ^3.15.0
+        version: 3.15.0(eslint@10.0.0)(svelte@packages+svelte)
       jsdom:
         specifier: 25.0.1
         version: 25.0.1
@@ -54,8 +57,8 @@ importers:
         specifier: ^5.5.4
         version: 5.5.4
       typescript-eslint:
-        specifier: ^8.48.1
-        version: 8.48.1(eslint@9.9.1)(typescript@5.5.4)
+        specifier: ^8.55.0
+        version: 8.55.0(eslint@10.0.0)(typescript@5.5.4)
       v8-natives:
         specifier: ^1.2.5
         version: 1.2.5
@@ -570,8 +573,8 @@ packages:
     cpu: [x64]
     os: [win32]
 
-  '@eslint-community/eslint-utils@4.9.0':
-    resolution: {integrity: sha512-ayVFHdtZ+hsq1t2Dy24wCmGXGe4q9Gu3smhLYALJrr473ZH27MsnSL+LKUlimp4BWJqMDMLmPpx/Q9R3OAlL4g==}
+  '@eslint-community/eslint-utils@4.9.1':
+    resolution: {integrity: sha512-phrYmNiYppR7znFEdqgfWHXR6NCkZEK7hwWDHZUjit/2/U0r6XvkDl0SYnoM51Hq7FhCGdLDT6zxCCOY1hexsQ==}
     engines: {node: ^12.22.0 || ^14.17.0 || >=16.0.0}
     peerDependencies:
       eslint: ^6.0.0 || ^7.0.0 || >=8.0.0
@@ -580,28 +583,49 @@ packages:
     resolution: {integrity: sha512-EriSTlt5OC9/7SXkRSCAhfSxxoSUgBm33OH+IkwbdpgoqsSsUg7y3uh+IICI/Qg4BBWr3U2i39RpmycbxMq4ew==}
     engines: {node: ^12.0.0 || ^14.0.0 || >=16.0.0}
 
-  '@eslint/config-array@0.18.0':
-    resolution: {integrity: sha512-fTxvnS1sRMu3+JjXwJG0j/i4RT9u4qJ+lqS/yCGap4lH4zZGzQ7tu+xZqQmcMZq5OBZDL4QRxQzRjkWcGt8IVw==}
-    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+  '@eslint/config-array@0.23.1':
+    resolution: {integrity: sha512-uVSdg/V4dfQmTjJzR0szNczjOH/J+FyUMMjYtr07xFRXR7EDf9i1qdxrD0VusZH9knj1/ecxzCQQxyic5NzAiA==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
 
-  '@eslint/eslintrc@3.1.0':
-    resolution: {integrity: sha512-4Bfj15dVJdoy3RfZmmo86RK1Fwzn6SstsvK9JS+BaVKqC6QQQQyXekNaC+g+LKNgkQ+2VhGAzm6hO40AhMR3zQ==}
-    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+  '@eslint/config-helpers@0.5.2':
+    resolution: {integrity: sha512-a5MxrdDXEvqnIq+LisyCX6tQMPF/dSJpCfBgBauY+pNZ28yCtSsTvyTYrMhaI+LK26bVyCJfJkT0u8KIj2i1dQ==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
 
-  '@eslint/js@9.9.1':
-    resolution: {integrity: sha512-xIDQRsfg5hNBqHz04H1R3scSVwmI+KUbqjsQKHKQ1DAUSaUjYPReZZmS/5PNiKu1fUvzDd6H7DEDKACSEhu+TQ==}
-    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+  '@eslint/core@1.1.0':
+    resolution: {integrity: sha512-/nr9K9wkr3P1EzFTdFdMoLuo1PmIxjmwvPozwoSodjNBdefGujXQUF93u1DDZpEaTuDvMsIQddsd35BwtrW9Xw==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
 
-  '@eslint/object-schema@2.1.4':
-    resolution: {integrity: sha512-BsWiH1yFGjXXS2yvrf5LyuoSIIbPrGUWob917o+BTKuZ7qJdxX8aJLRxs1fS9n6r7vESrq1OUqb68dANcFXuQQ==}
-    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+  '@eslint/js@10.0.1':
+    resolution: {integrity: sha512-zeR9k5pd4gxjZ0abRoIaxdc7I3nDktoXZk2qOv9gCNWx3mVwEn32VRhyLaRsDiJjTs0xq/T8mfPtyuXu7GWBcA==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
+    peerDependencies:
+      eslint: ^10.0.0
+    peerDependenciesMeta:
+      eslint:
+        optional: true
+
+  '@eslint/object-schema@3.0.1':
+    resolution: {integrity: sha512-P9cq2dpr+LU8j3qbLygLcSZrl2/ds/pUpfnHNNuk5HW7mnngHs+6WSq5C9mO3rqRX8A1poxqLTC9cu0KOyJlBg==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
+
+  '@eslint/plugin-kit@0.6.0':
+    resolution: {integrity: sha512-bIZEUzOI1jkhviX2cp5vNyXQc6olzb2ohewQubuYlMXZ2Q/XjBO0x0XhGPvc9fjSIiUN0vw+0hq53BJ4eQSJKQ==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
+
+  '@humanfs/core@0.19.1':
+    resolution: {integrity: sha512-5DyQ4+1JEUzejeK1JGICcideyfUbGixgS9jNgex5nqkW+cY7WZhxBigmieN5Qnw9ZosSNVC9KQKyb+GUaGyKUA==}
+    engines: {node: '>=18.18.0'}
+
+  '@humanfs/node@0.16.7':
+    resolution: {integrity: sha512-/zUx+yOsIrG4Y43Eh2peDeKCxlRt/gET6aHfaKpuq267qXdYDFViVHfMaLyygZOnl0kGWxFIgsBy8QFuTLUXEQ==}
+    engines: {node: '>=18.18.0'}
 
   '@humanwhocodes/module-importer@1.0.1':
     resolution: {integrity: sha512-bxveV4V8v5Yb4ncFTT3rPSgZBOpCkjfK0y4oVVVJwIuDVBRMDXrPyXRL988i5ap9m9bnyEEjWfm5WkBmtffLfA==}
     engines: {node: '>=12.22'}
 
-  '@humanwhocodes/retry@0.3.0':
-    resolution: {integrity: sha512-d2CGZR2o7fS6sWB7DG/3a95bGKQyHMACZ5aW8qGkkqQpUoZV6C0X7Pc7l4ZNMZkfNBf4VWNe9E1jRsf0G146Ew==}
+  '@humanwhocodes/retry@0.4.3':
+    resolution: {integrity: sha512-bV0Tgo9K4hfPCek+aMAn81RppFKv2ySDQeMoSZuvTASywNTnVJCArCZE2FWqpvIatKu7VMRLWlR1EazvVhDyhQ==}
     engines: {node: '>=18.18'}
 
   '@inquirer/external-editor@1.0.2':
@@ -613,6 +637,14 @@ packages:
       '@types/node':
         optional: true
 
+  '@isaacs/balanced-match@4.0.1':
+    resolution: {integrity: sha512-yzMTt9lEb8Gv7zRioUilSglI0c0smZ9k5D65677DLWLtWJaXIS3CqcGyUFByYKlnUj6TkjLVs54fBl6+TiGQDQ==}
+    engines: {node: 20 || >=22}
+
+  '@isaacs/brace-expansion@5.0.1':
+    resolution: {integrity: sha512-WMz71T1JS624nWj2n2fnYAuPovhv7EUhk69R6i9dsVyzxt5eM3bjwvgk9L+APE1TRscGysAVMANkB0jh0LQZrQ==}
+    engines: {node: 20 || >=22}
+
   '@isaacs/cliui@8.0.2':
     resolution: {integrity: sha512-O8jcjabXaleOG9DQ0+ARXWZBTfnP4WNAqzuiJK7ll44AmxGKv/J2M4TPjxjY3znBCfvBXFzucm1twdyFybFqEA==}
     engines: {node: '>=12'}
@@ -841,8 +873,8 @@ packages:
     peerDependencies:
       acorn: ^8.9.0
 
-  '@sveltejs/eslint-config@8.3.3':
-    resolution: {integrity: sha512-vkrQgEmhokFEOpuTo7NlVXJJMJJGNzxjmkQCTkHSwIOdzQSUukDIJ4038IjdcnIERSIlo4OpLAydWLx52BVyQA==}
+  '@sveltejs/eslint-config@8.3.5':
+    resolution: {integrity: sha512-f8g5v1GNQePIJq6Rh3mf0riXx+7+IsRaTS7nn8w7r2RZFPPkuBAHGcHST9BTJOQb5UCSnPmst7BJHEDIlVtP3A==}
     peerDependencies:
       '@stylistic/eslint-plugin-js': '>= 1'
       eslint: '>= 9'
@@ -877,6 +909,9 @@ packages:
   '@types/eslint@8.56.12':
     resolution: {integrity: sha512-03ruubjWyOHlmljCVoxSuNDdmfZDzsrrz0P2LeJsOXr+ZwFQ+0yQIwNCwt/GYhV7Z31fgtXJTAEs+FYlEL851g==}
 
+  '@types/esrecurse@4.3.1':
+    resolution: {integrity: sha512-xJBAbDifo5hpffDBuHl0Y8ywswbiAp/Wi7Y/GtAgSlZyIABppyurxVueOPE8LUQOxdlgi6Zqce7uoEpqNTeiUw==}
+
   '@types/estree@1.0.8':
     resolution: {integrity: sha512-dWHzHa2WqEXI/O1E9OjrocMTKJl2mSrEolh1Iomrv6U+JuNwaHXsXx9bLu5gG7BUWFIN0skIQJQ/L1rIex4X6w==}
 
@@ -898,63 +933,63 @@ packages:
   '@types/resolve@1.20.2':
     resolution: {integrity: sha512-60BCwRFOZCQhDncwQdxxeOEEkbc5dIMccYLwbxsS4TUNeVECQ/pBJ0j09mrHOl/JJvpRPGwO9SvE4nR2Nb/a4Q==}
 
-  '@typescript-eslint/eslint-plugin@8.48.1':
-    resolution: {integrity: sha512-X63hI1bxl5ohelzr0LY5coufyl0LJNthld+abwxpCoo6Gq+hSqhKwci7MUWkXo67mzgUK6YFByhmaHmUcuBJmA==}
+  '@typescript-eslint/eslint-plugin@8.55.0':
+    resolution: {integrity: sha512-1y/MVSz0NglV1ijHC8OT49mPJ4qhPYjiK08YUQVbIOyu+5k862LKUHFkpKHWu//zmr7hDR2rhwUm6gnCGNmGBQ==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
-      '@typescript-eslint/parser': ^8.48.1
+      '@typescript-eslint/parser': ^8.55.0
       eslint: ^8.57.0 || ^9.0.0
       typescript: '>=4.8.4 <6.0.0'
 
-  '@typescript-eslint/parser@8.48.1':
-    resolution: {integrity: sha512-PC0PDZfJg8sP7cmKe6L3QIL8GZwU5aRvUFedqSIpw3B+QjRSUZeeITC2M5XKeMXEzL6wccN196iy3JLwKNvDVA==}
+  '@typescript-eslint/parser@8.55.0':
+    resolution: {integrity: sha512-4z2nCSBfVIMnbuu8uinj+f0o4qOeggYJLbjpPHka3KH1om7e+H9yLKTYgksTaHcGco+NClhhY2vyO3HsMH1RGw==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
       eslint: ^8.57.0 || ^9.0.0
       typescript: '>=4.8.4 <6.0.0'
 
-  '@typescript-eslint/project-service@8.48.1':
-    resolution: {integrity: sha512-HQWSicah4s9z2/HifRPQ6b6R7G+SBx64JlFQpgSSHWPKdvCZX57XCbszg/bapbRsOEv42q5tayTYcEFpACcX1w==}
+  '@typescript-eslint/project-service@8.55.0':
+    resolution: {integrity: sha512-zRcVVPFUYWa3kNnjaZGXSu3xkKV1zXy8M4nO/pElzQhFweb7PPtluDLQtKArEOGmjXoRjnUZ29NjOiF0eCDkcQ==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
       typescript: '>=4.8.4 <6.0.0'
 
-  '@typescript-eslint/scope-manager@8.48.1':
-    resolution: {integrity: sha512-rj4vWQsytQbLxC5Bf4XwZ0/CKd362DkWMUkviT7DCS057SK64D5lH74sSGzhI6PDD2HCEq02xAP9cX68dYyg1w==}
+  '@typescript-eslint/scope-manager@8.55.0':
+    resolution: {integrity: sha512-fVu5Omrd3jeqeQLiB9f1YsuK/iHFOwb04bCtY4BSCLgjNbOD33ZdV6KyEqplHr+IlpgT0QTZ/iJ+wT7hvTx49Q==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
 
-  '@typescript-eslint/tsconfig-utils@8.48.1':
-    resolution: {integrity: sha512-k0Jhs4CpEffIBm6wPaCXBAD7jxBtrHjrSgtfCjUvPp9AZ78lXKdTR8fxyZO5y4vWNlOvYXRtngSZNSn+H53Jkw==}
+  '@typescript-eslint/tsconfig-utils@8.55.0':
+    resolution: {integrity: sha512-1R9cXqY7RQd7WuqSN47PK9EDpgFUK3VqdmbYrvWJZYDd0cavROGn+74ktWBlmJ13NXUQKlZ/iAEQHI/V0kKe0Q==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
       typescript: '>=4.8.4 <6.0.0'
 
-  '@typescript-eslint/type-utils@8.48.1':
-    resolution: {integrity: sha512-1jEop81a3LrJQLTf/1VfPQdhIY4PlGDBc/i67EVWObrtvcziysbLN3oReexHOM6N3jyXgCrkBsZpqwH0hiDOQg==}
+  '@typescript-eslint/type-utils@8.55.0':
+    resolution: {integrity: sha512-x1iH2unH4qAt6I37I2CGlsNs+B9WGxurP2uyZLRz6UJoZWDBx9cJL1xVN/FiOmHEONEg6RIufdvyT0TEYIgC5g==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
       eslint: ^8.57.0 || ^9.0.0
       typescript: '>=4.8.4 <6.0.0'
 
-  '@typescript-eslint/types@8.48.1':
-    resolution: {integrity: sha512-+fZ3LZNeiELGmimrujsDCT4CRIbq5oXdHe7chLiW8qzqyPMnn1puNstCrMNVAqwcl2FdIxkuJ4tOs/RFDBVc/Q==}
+  '@typescript-eslint/types@8.55.0':
+    resolution: {integrity: sha512-ujT0Je8GI5BJWi+/mMoR0wxwVEQaxM+pi30xuMiJETlX80OPovb2p9E8ss87gnSVtYXtJoU9U1Cowcr6w2FE0w==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
 
-  '@typescript-eslint/typescript-estree@8.48.1':
-    resolution: {integrity: sha512-/9wQ4PqaefTK6POVTjJaYS0bynCgzh6ClJHGSBj06XEHjkfylzB+A3qvyaXnErEZSaxhIo4YdyBgq6j4RysxDg==}
+  '@typescript-eslint/typescript-estree@8.55.0':
+    resolution: {integrity: sha512-EwrH67bSWdx/3aRQhCoxDaHM+CrZjotc2UCCpEDVqfCE+7OjKAGWNY2HsCSTEVvWH2clYQK8pdeLp42EVs+xQw==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
       typescript: '>=4.8.4 <6.0.0'
 
-  '@typescript-eslint/utils@8.48.1':
-    resolution: {integrity: sha512-fAnhLrDjiVfey5wwFRwrweyRlCmdz5ZxXz2G/4cLn0YDLjTapmN4gcCsTBR1N2rWnZSDeWpYtgLDsJt+FpmcwA==}
+  '@typescript-eslint/utils@8.55.0':
+    resolution: {integrity: sha512-BqZEsnPGdYpgyEIkDC1BadNY8oMwckftxBT+C8W0g1iKPdeqKZBtTfnvcq0nf60u7MkjFO8RBvpRGZBPw4L2ow==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
       eslint: ^8.57.0 || ^9.0.0
       typescript: '>=4.8.4 <6.0.0'
 
-  '@typescript-eslint/visitor-keys@8.48.1':
-    resolution: {integrity: sha512-BmxxndzEWhE4TIEEMBs8lP3MBWN3jFPs/p6gPm/wkv02o41hI6cq9AuSmGAaTTHPtA1FTi2jBre4A9rm5ZmX+Q==}
+  '@typescript-eslint/visitor-keys@8.55.0':
+    resolution: {integrity: sha512-AxNRwEie8Nn4eFS1FzDMJWIISMGoXMb037sgCBJ3UR6o0fQTzr2tqN9WT+DkWJPhIdQCfV7T6D387566VtnCJA==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
 
   '@vitest/coverage-v8@2.1.9':
@@ -1079,9 +1114,6 @@ packages:
   birpc@2.5.0:
     resolution: {integrity: sha512-VSWO/W6nNQdyP520F1mhf+Lc2f8pjGQOtoHHm7Ze8Go1kX7akpVIrtTa0fn+HB0QJEDVacl6aO08YE0PgXfdnQ==}
 
-  brace-expansion@1.1.12:
-    resolution: {integrity: sha512-9T9UjW3r0UW5c1Q7GTwllptXwhvYmEzFhzMfZ9H7FQWt+uZePjZPjBP/W1ZEyZ1twGWom5/56TF4lPcqjnDHcg==}
-
   brace-expansion@2.0.2:
     resolution: {integrity: sha512-Jt0vHyM+jmUBqojB7E1NIYadt0vI0Qxjxd2TErW94wDz+E2LAm5vKMXXwg6ZZBTHPuUlDgQHKXvjGBdfcF1ZDQ==}
 
@@ -1100,18 +1132,10 @@ packages:
     resolution: {integrity: sha512-b6Ilus+c3RrdDk+JhLKUAQfzzgLEPy6wcXqS7f/xe1EETvsDP6GORG7SFuOs6cID5YkqchW/LXZbX5bc8j7ZcQ==}
     engines: {node: '>=8'}
 
-  callsites@3.1.0:
-    resolution: {integrity: sha512-P8BjAsXvZS+VIDUI11hHCQEv74YT67YUi5JJFNWIqL235sBmjX4+qx9Muvls5ivyNENctx46xQLQ3aTuE7ssaQ==}
-    engines: {node: '>=6'}
-
   chai@5.3.3:
     resolution: {integrity: sha512-4zNhdJD/iOjSH0A05ea+Ke6MU5mmpQcbQsSOkgdaUMJ9zTlDTD/GYlwohmIE2u0gaxHYiVHEn1Fw9mZ/ktJWgw==}
     engines: {node: '>=18'}
 
-  chalk@4.1.2:
-    resolution: {integrity: sha512-oKnbhFyRIXpUuez8iBMmyEa4nbj4IOQyuhc/wy9kY7/WVPcwIO9VA668Pu8RkO7+0G76SLROeyw9CpQ061i4mA==}
-    engines: {node: '>=10'}
-
   chardet@2.1.0:
     resolution: {integrity: sha512-bNFETTG/pM5ryzQ9Ad0lJOTa6HWD/YsScAR3EnCPZRPlQh77JocYktSHOUHelyhm8IARL+o4c4F1bP5KVOjiRA==}
 
@@ -1148,9 +1172,6 @@ packages:
   commondir@1.0.1:
     resolution: {integrity: sha512-W9pAhw0ja1Edb5GVdIF1mjZw/ASI0AlShXM83UUGe2DVr5TdAPEA1OA8m/g8zWp9x6On7gqufY+FatDbC3MDQg==}
 
-  concat-map@0.0.1:
-    resolution: {integrity: sha512-/Srv4dswyQNBfohGpz9o6Yb3Gz3SrUDqBH5rTuhGR7ahtlbYKnVxw2bCFMRljaA7EXHaXZ8wsHdodFvbkhKmqg==}
-
   cross-spawn@7.0.6:
     resolution: {integrity: sha512-uV2QOWP2nWzsy2aMp8aRibhi9dlzF5Hgh5SHaB9OiTGEyDTiJJyx0uy51QXdyWbtAHNua4XJzUKca3OzKUd3vA==}
     engines: {node: '>= 8'}
@@ -1295,8 +1316,10 @@ packages:
     peerDependencies:
       eslint: '>=8'
 
-  eslint-plugin-lube@0.4.3:
-    resolution: {integrity: sha512-BVO83tRo090d6a04cl45Gb761SD79cOT6wKxxWrpsH7Rv8I0SJvc79ijE11vvyxxCMiGUVq/w4NqqPJAHyYfSQ==}
+  eslint-plugin-lube@0.5.1:
+    resolution: {integrity: sha512-z01UM0LAI/Z+b9qGoVqN3RNycXbYXi6i4/QT0He58LdBVmmOd+z4tJQmvOqEh3A4TVtSQcGYq4/4wX/OebGISQ==}
+    peerDependencies:
+      eslint: '>=9.0.0'
 
   eslint-plugin-n@17.16.1:
     resolution: {integrity: sha512-/7FVAwjUrix9P5lycnsYRIQRwFo/DZROD+ZXWLpE+/EZWLyuLvyFaRdAPYJSz+nlAdZIZp+LAzlBerQSVYUNFg==}
@@ -1304,11 +1327,11 @@ packages:
     peerDependencies:
       eslint: '>=8.23.0'
 
-  eslint-plugin-svelte@3.11.0:
-    resolution: {integrity: sha512-KliWlkieHyEa65aQIkRwUFfHzT5Cn4u3BQQsu3KlkJOs7c1u7ryn84EWaOjEzilbKgttT4OfBURA8Uc4JBSQIw==}
+  eslint-plugin-svelte@3.15.0:
+    resolution: {integrity: sha512-QKB7zqfuB8aChOfBTComgDptMf2yxiJx7FE04nneCmtQzgTHvY8UJkuh8J2Rz7KB9FFV9aTHX6r7rdYGvG8T9Q==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
-      eslint: ^8.57.1 || ^9.0.0
+      eslint: ^8.57.1 || ^9.0.0 || ^10.0.0
       svelte: ^3.37.0 || ^4.0.0 || ^5.0.0
     peerDependenciesMeta:
       svelte:
@@ -1318,6 +1341,10 @@ packages:
     resolution: {integrity: sha512-sNXOfKCn74rt8RICKMvJS7XKV/Xk9kA7DyJr8mJik3S7Cwgy3qlkkmyS2uQB3jiJg6VNdZd/pDBJu0nvG2NlTg==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
 
+  eslint-scope@9.1.0:
+    resolution: {integrity: sha512-CkWE42hOJsNj9FJRaoMX9waUFYhqY4jmyLFdAdzZr6VaCg3ynLYx4WnOdkaIifGfH4gsUcBTn4OZbHXkpLD0FQ==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
+
   eslint-visitor-keys@3.4.3:
     resolution: {integrity: sha512-wpc+LXeiyiisxPlEkUzU6svyS1frIO3Mgxj1fdy7Pm8Ygzguax2N3Fa/D/ag1WqbOprdI+uY6wMUl8/a2G+iag==}
     engines: {node: ^12.22.0 || ^14.17.0 || >=16.0.0}
@@ -1326,9 +1353,13 @@ packages:
     resolution: {integrity: sha512-Uhdk5sfqcee/9H/rCOJikYz67o0a2Tw2hGRPOG2Y1R2dg7brRe1uG0yaNQDHu+TO/uQPF/5eCapvYSmHUjt7JQ==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
 
-  eslint@9.9.1:
-    resolution: {integrity: sha512-dHvhrbfr4xFQ9/dq+jcVneZMyRYLjggWjk6RVsIiHsP8Rz6yZ8LvZ//iU4TrZF+SXWG+JkNF2OyiZRvzgRDqMg==}
-    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+  eslint-visitor-keys@5.0.0:
+    resolution: {integrity: sha512-A0XeIi7CXU7nPlfHS9loMYEKxUaONu/hTEzHTGba9Huu94Cq1hPivf+DE5erJozZOky0LfvXAyrV/tcswpLI0Q==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
+
+  eslint@10.0.0:
+    resolution: {integrity: sha512-O0piBKY36YSJhlFSG8p9VUdPV/SxxS4FYDWVpr/9GJuMaepzwlf4J8I4ov1b+ySQfDTPhc3DtLaxcT1fN0yqCg==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
     hasBin: true
     peerDependencies:
       jiti: '*'
@@ -1343,6 +1374,10 @@ packages:
     resolution: {integrity: sha512-M1M6CpiE6ffoigIOWYO9UDP8TMUw9kqb21tf+08IgDYjCsOvCuDt4jQcZmoYxx+w7zlKw9/N0KXfto+I8/FrXA==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
 
+  espree@11.1.0:
+    resolution: {integrity: sha512-WFWYhO1fV4iYkqOOvq8FbqIhr2pYfoDY0kCotMkDeNtGpiGGkZ1iov2u8ydjtgM8yF8rzK7oaTbw2NAzbAbehw==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
+
   espree@9.6.1:
     resolution: {integrity: sha512-oruZaFkjorTpF32kDSI5/75ViwGeZginGGy2NoOSg3Q9bnwlnmDm4HLnkl0RE3n+njDXR037aY1+x58Z/zFdwQ==}
     engines: {node: ^12.22.0 || ^14.17.0 || >=16.0.0}
@@ -1352,8 +1387,8 @@ packages:
     engines: {node: '>=4'}
     hasBin: true
 
-  esquery@1.5.0:
-    resolution: {integrity: sha512-YQLXUplAwJgCydQ78IMJywZCceoqk1oH01OERdSAJc/7U2AylwjhSCLDEtqwg811idIS/9fIU5GjG73IgjKMVg==}
+  esquery@1.7.0:
+    resolution: {integrity: sha512-Ap6G0WQwcU/LHsvLwON1fAQX9Zp0A2Y6Y/cJBl9r/JbW90Zyg4/zbG6zzKa2OTALELarYHmKu0GhpM5EO+7T0g==}
     engines: {node: '>=0.10'}
 
   esrap@2.2.2:
@@ -1474,12 +1509,9 @@ packages:
 
   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@14.0.0:
-    resolution: {integrity: sha512-oahGvuMGQlPw/ivIYBjVSrWAfWLBeku5tpPE2fOPLi+WHffIWbuh2tCjhyQhTBPMf5E9jDEH4FOmTYgYwbKwtQ==}
-    engines: {node: '>=18'}
-
   globals@15.15.0:
     resolution: {integrity: sha512-7ACyT3wmyp3I61S4fG682L0VA2RGD9otkqGJIwNUMF1SWUombIIk+af1unuDYgMm082aHYwD+mzJvv9Iu8dsgg==}
     engines: {node: '>=18'}
@@ -1488,6 +1520,10 @@ packages:
     resolution: {integrity: sha512-bqWEnJ1Nt3neqx2q5SFfGS8r/ahumIakg3HcwtNlrVlwXIeNumWn/c7Pn/wKzGhf6SaW6H6uWXLqC30STCMchQ==}
     engines: {node: '>=18'}
 
+  globals@17.3.0:
+    resolution: {integrity: sha512-yMqGUQVVCkD4tqjOJf3TnrvaaHDMYp4VlUSObbkIiuCPe/ofdMBFIAcBbCSRFWOnos6qRiTVStDwqPLUclaxIw==}
+    engines: {node: '>=18'}
+
   globby@11.1.0:
     resolution: {integrity: sha512-jhIXaOzy1sb8IyocaruWSn1TjmnBVs8Ayhcy83rmxNJ8q2uWKCAj3CnJY+KpGSXCueAPc0i05kVvVKtP1t9S3g==}
     engines: {node: '>=10'}
@@ -1495,9 +1531,6 @@ packages:
   graceful-fs@4.2.11:
     resolution: {integrity: sha512-RbJ5/jmFcNNCcDV5o9eTnBLJ/HszWV0P73bc+Ff4nS/rJj+YaS6IGyiOL0VoBYX+l1Wrl3k63h/KrH+nhJ0XvQ==}
 
-  graphemer@1.4.0:
-    resolution: {integrity: sha512-EtKwoO6kxCL9WO5xipiHTZlSzBm7WLT627TqC/uVRd0HKmq8NXyebnNYxDoBi7wt8eTWrUrKXCOVaFq9x1kgag==}
-
   has-flag@4.0.0:
     resolution: {integrity: sha512-EykJT/Q1KjTWctppgIAgfSO0tKVuZUjhgMr17kqTumMl6Afv3EISleU7qZUzoXDFTAHTDC4NOoG/ZxU3EvlMPQ==}
     engines: {node: '>=8'}
@@ -1544,10 +1577,6 @@ packages:
   immutable@4.3.7:
     resolution: {integrity: sha512-1hqclzwYwjRDFLjcFxOM5AYkkG0rpFPpr1RLPMEuGczoS7YA8gLhy8SWXYRAA/XwfEHpfo3cw5JGioS32fnMRw==}
 
-  import-fresh@3.3.0:
-    resolution: {integrity: sha512-veYYhQa+D1QBKznvhUHxb8faxlrwUnxseDAbAp457E0wLNio2bOSKnjYDhMj+YiAq61xrMGhQk9iXVk5FzgQMw==}
-    engines: {node: '>=6'}
-
   imurmurhash@0.1.4:
     resolution: {integrity: sha512-JmXMZ6wuvDmLiHEml9ykzqO6lwFbof0GG4IkcGaENdCRDDmMVnny7s5HsIgHCbaq0w2MyPhDqkhTUgS2LU2PHA==}
     engines: {node: '>=0.8.19'}
@@ -1588,10 +1617,6 @@ packages:
     resolution: {integrity: sha512-41Cifkg6e8TylSpdtTpeLVMqvSBEVzTttHvERD741+pnZ8ANv0004MRL43QKPDlK9cGvNp6NZWZUBlbGXYxxng==}
     engines: {node: '>=0.12.0'}
 
-  is-path-inside@3.0.3:
-    resolution: {integrity: sha512-Fd4gABb+ycGAmKou8eMftCupSir5lRxqf4aD/vd0cD2qc4HL07OjCeuHMr8Ro4CoMaeCKDB0/ECBOVWjTwUvPQ==}
-    engines: {node: '>=8'}
-
   is-potential-custom-element-name@1.0.1:
     resolution: {integrity: sha512-bCYeRA2rVibKZd+s2625gGnGF/t7DSqDs4dP7CrLA1m7jKWz6pps0LpYLJN8Q64HtmPKJ1hrN3nzPNKFEKOUiQ==}
 
@@ -1751,9 +1776,6 @@ packages:
     resolution: {integrity: sha512-iPZK6eYjbxRu3uB4/WZ3EsEIMJFMqAoopl3R+zuq0UjcAm/MO6KCweDgPfP3elTztoKP3KtnVHxTn2NHBSDVUw==}
     engines: {node: '>=10'}
 
-  lodash.merge@4.6.2:
-    resolution: {integrity: sha512-0KpjqXRVvrYyCsX1swR/XTK0va6VQkQM6MNo7PqW77ByjAhoARA8EfrP1N4+KlKj8YS0ZUCtRT/YUuhyYDujIQ==}
-
   lodash.startcase@4.4.0:
     resolution: {integrity: sha512-+WKqsK294HMSc2jEbNgpHpd0JfIBhp7rEV4aqXWqFr6AlXov+SlcgB1Fv01y2kGe3Gc8nMW7VA0SrGuSkRfIEg==}
 
@@ -1789,8 +1811,9 @@ packages:
     resolution: {integrity: sha512-ZDY+bPm5zTTF+YpCrAU9nK0UgICYPT0QtT1NZWFv4s++TNkcgVaT0g6+4R2uI4MjQjzysHB1zxuWL50hzaeXiw==}
     engines: {node: '>= 0.6'}
 
-  minimatch@3.1.2:
-    resolution: {integrity: sha512-J7p63hRiAjw1NDEww1W7i37+ByIrOWO5XQQAzZ3VOcL0PNybwpfmV/N05zFAzwQ9USyEcX6t3UO+K5aqBQOIHw==}
+  minimatch@10.1.2:
+    resolution: {integrity: sha512-fu656aJ0n2kcXwsnwnv9g24tkU5uSmOlTjd6WyyaKm2Z+h1qmY6bAjrcaIxF/BslFqbZ8UBtbJi7KgQOZD2PTw==}
+    engines: {node: 20 || >=22}
 
   minimatch@9.0.5:
     resolution: {integrity: sha512-G6T0ZX48xgozx7587koeX9Ys2NYy6Gmv//P89sEte9V9whIapMNF4idKxnW2QtCcLiTWlb/wfCabAtAFWhhBow==}
@@ -1883,10 +1906,6 @@ packages:
   package-manager-detector@0.2.11:
     resolution: {integrity: sha512-BEnLolu+yuz22S56CU1SUKq3XC3PkwD5wv4ikR4MfGvnRVcmzXR9DwSlW2fEamyTPyXHomBJRzgapeuBvRNzJQ==}
 
-  parent-module@1.0.1:
-    resolution: {integrity: sha512-GQ2EWRpQV8/o+Aw8YqtfZZPfNRWZYkbidE9k5rpl/hC3vtHHBfGm2Ifi6qWV+coDGkrUKZAxE3Lot5kcsRlh+g==}
-    engines: {node: '>=6'}
-
   parse5@7.1.2:
     resolution: {integrity: sha512-Czj1WaSVpaoj0wbhMzLmWD69anp2WH7FXMB9n1Sy8/ZFF9jolSQVMu1Ij5WIyGmcBmhk7EOndpO4mIpihVqAXw==}
 
@@ -2028,10 +2047,6 @@ packages:
     resolution: {integrity: sha512-RSYAtP31mvYLkAHrOlh25pCNQ5hWnT106VukGaaFfuJrZFkGRX5GhUAdPqpSDXxOhA2c4akmRuplv1mRqnBn6Q==}
     engines: {node: '>=8'}
 
-  resolve-from@4.0.0:
-    resolution: {integrity: sha512-pb/MYmXstAkysRFx8piNI1tGFNQIFA3vkE3Gq4EuA1dF6gHp/+vgZqsCGJapvy8N3Q+4o7FwvquPJcnZ7RYy4g==}
-    engines: {node: '>=4'}
-
   resolve-from@5.0.0:
     resolution: {integrity: sha512-qYg9KP24dD5qka9J47d0aVky0N+b4fTU89LN9iDnjB5waksiC49rvMB0PrUJQGoTmH50XPiqOvAjDfaijGxYZw==}
     engines: {node: '>=8'}
@@ -2162,10 +2177,6 @@ packages:
     resolution: {integrity: sha512-vavAMRXOgBVNF6nyEEmL3DBK19iRpDcoIwW+swQ+CbGiu7lju6t+JklA1MHweoWtadgt4ISVUsXLyDq34ddcwA==}
     engines: {node: '>=4'}
 
-  strip-json-comments@3.1.1:
-    resolution: {integrity: sha512-6fPc+R4ihwqP6N/aIv2f1gMH8lOVtWQHoqC4yK6oSDVVocumAsfCqjkXnqiYMhmMwS/mEHLp7Vehlt3ql6lEig==}
-    engines: {node: '>=8'}
-
   supports-color@7.2.0:
     resolution: {integrity: sha512-qpCAvRl9stuOHveKsn7HncJRvv501qIacKzQlO/+Lwxc9+0q2wLyv4Dfvt80/DPn2pqOBsJdDiogXGR9+OvwRw==}
     engines: {node: '>=8'}
@@ -2174,9 +2185,9 @@ packages:
     resolution: {integrity: sha512-ot0WnXS9fgdkgIcePe6RHNk1WA8+muPa6cSjeR3V8K27q9BB1rTE3R1p7Hv0z1ZyAc8s6Vvv8DIyWf681MAt0w==}
     engines: {node: '>= 0.4'}
 
-  svelte-eslint-parser@1.3.0:
-    resolution: {integrity: sha512-VCgMHKV7UtOGcGLGNFSbmdm6kEKjtzo5nnpGU/mnx4OsFY6bZ7QwRF5DUx+Hokw5Lvdyo8dpk8B1m8mliomrNg==}
-    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+  svelte-eslint-parser@1.4.1:
+    resolution: {integrity: sha512-1eqkfQ93goAhjAXxZiu1SaKI9+0/sxp4JIWQwUpsz7ybehRE5L8dNuz7Iry7K22R47p5/+s9EM+38nHV2OlgXA==}
+    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0, pnpm: 10.24.0}
     peerDependencies:
       svelte: ^3.37.0 || ^4.0.0 || ^5.0.0
     peerDependenciesMeta:
@@ -2203,9 +2214,6 @@ packages:
     resolution: {integrity: sha512-pFYqmTw68LXVjeWJMST4+borgQP2AyMNbg1BpZh9LbyhUeNkeaPF9gzfPGUAnSMV3qPYdWUwDIjjCLiSDOl7vg==}
     engines: {node: '>=18'}
 
-  text-table@0.2.0:
-    resolution: {integrity: sha512-N+8UisAXDGk8PFXP4HAzVR9nbfmVJ3zYLAWiTIoqC5v5isinhr+r5uaO8+7r3BMfuNIufIsA7RdpVgacC2cSpw==}
-
   tinybench@2.9.0:
     resolution: {integrity: sha512-0+DUvqWMValLmha6lr4kD8iAMK1HzV0/aKnCtWb9v9641TnP/MFb7Pc2bxoxQjTXAErryXVgUOfv2YqNllqGeg==}
 
@@ -2268,8 +2276,8 @@ packages:
     peerDependencies:
       typescript: '>=4.2.0'
 
-  ts-api-utils@2.1.0:
-    resolution: {integrity: sha512-CUgTZL1irw8u29bzrOD/nH85jqyc74D6SshFgujOIA7osm2Rz7dYH77agkx7H4FBNxDq7Cjf+IjaX/8zwFW+ZQ==}
+  ts-api-utils@2.4.0:
+    resolution: {integrity: sha512-3TaVTaAv2gTiMB35i3FiGJaRfwb3Pyn/j3m/bfAvGe8FB7CF6u+LMYqYlDh7reQf7UNvoTvdfAqHGmPGOSsPmA==}
     engines: {node: '>=18.12'}
     peerDependencies:
       typescript: '>=4.8.4'
@@ -2283,8 +2291,8 @@ packages:
     resolution: {integrity: sha512-XleUoc9uwGXqjWwXaUTZAmzMcFZ5858QA2vvx1Ur5xIcixXIP+8LnFDgRplU30us6teqdlskFfu+ae4K79Ooew==}
     engines: {node: '>= 0.8.0'}
 
-  typescript-eslint@8.48.1:
-    resolution: {integrity: sha512-FbOKN1fqNoXp1hIl5KYpObVrp0mCn+CLgn479nmu2IsRMrx2vyv74MmsBLVlhg8qVwNFGbXSp8fh1zp8pEoC2A==}
+  typescript-eslint@8.55.0:
+    resolution: {integrity: sha512-HE4wj+r5lmDVS9gdaN0/+iqNvPZwGfnJ5lZuz7s5vLlg9ODw0bIiiETaios9LvFI1U94/VBXGm3CB2Y5cNFMpw==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
       eslint: ^8.57.0 || ^9.0.0
@@ -2471,6 +2479,7 @@ packages:
   whatwg-encoding@3.1.1:
     resolution: {integrity: sha512-6qN4hJdMwfYBtE3YBTTHhoeuUrDBPZmbQaxWAqSALV/MeEnR5z1xd8UKud2RAkFoPkmB+hli1TZSnyi84xz1vQ==}
     engines: {node: '>=18'}
+    deprecated: Use @exodus/bytes instead for a more spec-conformant and faster implementation
 
   whatwg-mimetype@4.0.0:
     resolution: {integrity: sha512-QaKxh0eNIi2mE9p2vEdzfagOKHCcj1pJ56EEHGQOVxp8r9/iszLUUV7v89x9O1p/T+NlTM5W7jW6+cz4Fq1YVg==}
@@ -2860,42 +2869,50 @@ snapshots:
   '@esbuild/win32-x64@0.25.11':
     optional: true
 
-  '@eslint-community/eslint-utils@4.9.0(eslint@9.9.1)':
+  '@eslint-community/eslint-utils@4.9.1(eslint@10.0.0)':
     dependencies:
-      eslint: 9.9.1
+      eslint: 10.0.0
       eslint-visitor-keys: 3.4.3
 
   '@eslint-community/regexpp@4.12.2': {}
 
-  '@eslint/config-array@0.18.0':
+  '@eslint/config-array@0.23.1':
     dependencies:
-      '@eslint/object-schema': 2.1.4
+      '@eslint/object-schema': 3.0.1
       debug: 4.4.3
-      minimatch: 3.1.2
+      minimatch: 10.1.2
     transitivePeerDependencies:
       - supports-color
 
-  '@eslint/eslintrc@3.1.0':
+  '@eslint/config-helpers@0.5.2':
     dependencies:
-      ajv: 6.12.6
-      debug: 4.4.3
-      espree: 10.1.0
-      globals: 14.0.0
-      ignore: 5.3.2
-      import-fresh: 3.3.0
-      js-yaml: 4.1.1
-      minimatch: 3.1.2
-      strip-json-comments: 3.1.1
-    transitivePeerDependencies:
-      - supports-color
+      '@eslint/core': 1.1.0
 
-  '@eslint/js@9.9.1': {}
+  '@eslint/core@1.1.0':
+    dependencies:
+      '@types/json-schema': 7.0.15
 
-  '@eslint/object-schema@2.1.4': {}
+  '@eslint/js@10.0.1(eslint@10.0.0)':
+    optionalDependencies:
+      eslint: 10.0.0
+
+  '@eslint/object-schema@3.0.1': {}
+
+  '@eslint/plugin-kit@0.6.0':
+    dependencies:
+      '@eslint/core': 1.1.0
+      levn: 0.4.1
+
+  '@humanfs/core@0.19.1': {}
+
+  '@humanfs/node@0.16.7':
+    dependencies:
+      '@humanfs/core': 0.19.1
+      '@humanwhocodes/retry': 0.4.3
 
   '@humanwhocodes/module-importer@1.0.1': {}
 
-  '@humanwhocodes/retry@0.3.0': {}
+  '@humanwhocodes/retry@0.4.3': {}
 
   '@inquirer/external-editor@1.0.2(@types/node@20.19.17)':
     dependencies:
@@ -2904,6 +2921,12 @@ snapshots:
     optionalDependencies:
       '@types/node': 20.19.17
 
+  '@isaacs/balanced-match@4.0.1': {}
+
+  '@isaacs/brace-expansion@5.0.1':
+    dependencies:
+      '@isaacs/balanced-match': 4.0.1
+
   '@isaacs/cliui@8.0.2':
     dependencies:
       string-width: 5.1.2
@@ -3087,12 +3110,12 @@ snapshots:
   '@rollup/rollup-win32-x64-msvc@4.52.5':
     optional: true
 
-  '@stylistic/eslint-plugin-js@1.8.0(eslint@9.9.1)':
+  '@stylistic/eslint-plugin-js@1.8.0(eslint@10.0.0)':
     dependencies:
       '@types/eslint': 8.56.12
       acorn: 8.15.0
       escape-string-regexp: 4.0.0
-      eslint: 9.9.1
+      eslint: 10.0.0
       eslint-visitor-keys: 3.4.3
       espree: 9.6.1
 
@@ -3100,16 +3123,16 @@ snapshots:
     dependencies:
       acorn: 8.15.0
 
-  '@sveltejs/eslint-config@8.3.3(@stylistic/eslint-plugin-js@1.8.0(eslint@9.9.1))(eslint-config-prettier@9.1.0(eslint@9.9.1))(eslint-plugin-n@17.16.1(eslint@9.9.1)(typescript@5.5.4))(eslint-plugin-svelte@3.11.0(eslint@9.9.1)(svelte@packages+svelte))(eslint@9.9.1)(typescript-eslint@8.48.1(eslint@9.9.1)(typescript@5.5.4))(typescript@5.5.4)':
+  '@sveltejs/eslint-config@8.3.5(@stylistic/eslint-plugin-js@1.8.0(eslint@10.0.0))(eslint-config-prettier@9.1.0(eslint@10.0.0))(eslint-plugin-n@17.16.1(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@8.55.0(eslint@10.0.0)(typescript@5.5.4))(typescript@5.5.4)':
     dependencies:
-      '@stylistic/eslint-plugin-js': 1.8.0(eslint@9.9.1)
-      eslint: 9.9.1
-      eslint-config-prettier: 9.1.0(eslint@9.9.1)
-      eslint-plugin-n: 17.16.1(eslint@9.9.1)(typescript@5.5.4)
-      eslint-plugin-svelte: 3.11.0(eslint@9.9.1)(svelte@packages+svelte)
-      globals: 15.15.0
+      '@stylistic/eslint-plugin-js': 1.8.0(eslint@10.0.0)
+      eslint: 10.0.0
+      eslint-config-prettier: 9.1.0(eslint@10.0.0)
+      eslint-plugin-n: 17.16.1(eslint@10.0.0)(typescript@5.5.4)
+      eslint-plugin-svelte: 3.15.0(eslint@10.0.0)(svelte@packages+svelte)
+      globals: 17.3.0
       typescript: 5.5.4
-      typescript-eslint: 8.48.1(eslint@9.9.1)(typescript@5.5.4)
+      typescript-eslint: 8.55.0(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@7.1.11(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)))(svelte@packages+svelte)(vite@7.1.11(@types/node@24.5.2)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))':
     dependencies:
@@ -3146,6 +3169,8 @@ snapshots:
       '@types/estree': 1.0.8
       '@types/json-schema': 7.0.15
 
+  '@types/esrecurse@4.3.1': {}
+
   '@types/estree@1.0.8': {}
 
   '@types/json-schema@7.0.15': {}
@@ -3164,96 +3189,95 @@ snapshots:
 
   '@types/resolve@1.20.2': {}
 
-  '@typescript-eslint/eslint-plugin@8.48.1(@typescript-eslint/parser@8.48.1(eslint@9.9.1)(typescript@5.5.4))(eslint@9.9.1)(typescript@5.5.4)':
+  '@typescript-eslint/eslint-plugin@8.55.0(@typescript-eslint/parser@8.55.0(eslint@10.0.0)(typescript@5.5.4))(eslint@10.0.0)(typescript@5.5.4)':
     dependencies:
       '@eslint-community/regexpp': 4.12.2
-      '@typescript-eslint/parser': 8.48.1(eslint@9.9.1)(typescript@5.5.4)
-      '@typescript-eslint/scope-manager': 8.48.1
-      '@typescript-eslint/type-utils': 8.48.1(eslint@9.9.1)(typescript@5.5.4)
-      '@typescript-eslint/utils': 8.48.1(eslint@9.9.1)(typescript@5.5.4)
-      '@typescript-eslint/visitor-keys': 8.48.1
-      eslint: 9.9.1
-      graphemer: 1.4.0
+      '@typescript-eslint/parser': 8.55.0(eslint@10.0.0)(typescript@5.5.4)
+      '@typescript-eslint/scope-manager': 8.55.0
+      '@typescript-eslint/type-utils': 8.55.0(eslint@10.0.0)(typescript@5.5.4)
+      '@typescript-eslint/utils': 8.55.0(eslint@10.0.0)(typescript@5.5.4)
+      '@typescript-eslint/visitor-keys': 8.55.0
+      eslint: 10.0.0
       ignore: 7.0.5
       natural-compare: 1.4.0
-      ts-api-utils: 2.1.0(typescript@5.5.4)
+      ts-api-utils: 2.4.0(typescript@5.5.4)
       typescript: 5.5.4
     transitivePeerDependencies:
       - supports-color
 
-  '@typescript-eslint/parser@8.48.1(eslint@9.9.1)(typescript@5.5.4)':
+  '@typescript-eslint/parser@8.55.0(eslint@10.0.0)(typescript@5.5.4)':
     dependencies:
-      '@typescript-eslint/scope-manager': 8.48.1
-      '@typescript-eslint/types': 8.48.1
-      '@typescript-eslint/typescript-estree': 8.48.1(typescript@5.5.4)
-      '@typescript-eslint/visitor-keys': 8.48.1
+      '@typescript-eslint/scope-manager': 8.55.0
+      '@typescript-eslint/types': 8.55.0
+      '@typescript-eslint/typescript-estree': 8.55.0(typescript@5.5.4)
+      '@typescript-eslint/visitor-keys': 8.55.0
       debug: 4.4.3
-      eslint: 9.9.1
+      eslint: 10.0.0
       typescript: 5.5.4
     transitivePeerDependencies:
       - supports-color
 
-  '@typescript-eslint/project-service@8.48.1(typescript@5.5.4)':
+  '@typescript-eslint/project-service@8.55.0(typescript@5.5.4)':
     dependencies:
-      '@typescript-eslint/tsconfig-utils': 8.48.1(typescript@5.5.4)
-      '@typescript-eslint/types': 8.48.1
+      '@typescript-eslint/tsconfig-utils': 8.55.0(typescript@5.5.4)
+      '@typescript-eslint/types': 8.55.0
       debug: 4.4.3
       typescript: 5.5.4
     transitivePeerDependencies:
       - supports-color
 
-  '@typescript-eslint/scope-manager@8.48.1':
+  '@typescript-eslint/scope-manager@8.55.0':
     dependencies:
-      '@typescript-eslint/types': 8.48.1
-      '@typescript-eslint/visitor-keys': 8.48.1
+      '@typescript-eslint/types': 8.55.0
+      '@typescript-eslint/visitor-keys': 8.55.0
 
-  '@typescript-eslint/tsconfig-utils@8.48.1(typescript@5.5.4)':
+  '@typescript-eslint/tsconfig-utils@8.55.0(typescript@5.5.4)':
     dependencies:
       typescript: 5.5.4
 
-  '@typescript-eslint/type-utils@8.48.1(eslint@9.9.1)(typescript@5.5.4)':
+  '@typescript-eslint/type-utils@8.55.0(eslint@10.0.0)(typescript@5.5.4)':
     dependencies:
-      '@typescript-eslint/types': 8.48.1
-      '@typescript-eslint/typescript-estree': 8.48.1(typescript@5.5.4)
-      '@typescript-eslint/utils': 8.48.1(eslint@9.9.1)(typescript@5.5.4)
+      '@typescript-eslint/types': 8.55.0
+      '@typescript-eslint/typescript-estree': 8.55.0(typescript@5.5.4)
+      '@typescript-eslint/utils': 8.55.0(eslint@10.0.0)(typescript@5.5.4)
       debug: 4.4.3
-      eslint: 9.9.1
-      ts-api-utils: 2.1.0(typescript@5.5.4)
+      eslint: 10.0.0
+      ts-api-utils: 2.4.0(typescript@5.5.4)
       typescript: 5.5.4
     transitivePeerDependencies:
       - supports-color
 
-  '@typescript-eslint/types@8.48.1': {}
+  '@typescript-eslint/types@8.55.0': {}
 
-  '@typescript-eslint/typescript-estree@8.48.1(typescript@5.5.4)':
+  '@typescript-eslint/typescript-estree@8.55.0(typescript@5.5.4)':
     dependencies:
-      '@typescript-eslint/project-service': 8.48.1(typescript@5.5.4)
-      '@typescript-eslint/tsconfig-utils': 8.48.1(typescript@5.5.4)
-      '@typescript-eslint/types': 8.48.1
-      '@typescript-eslint/visitor-keys': 8.48.1
+      '@typescript-eslint/project-service': 8.55.0(typescript@5.5.4)
+      '@typescript-eslint/tsconfig-utils': 8.55.0(typescript@5.5.4)
+      '@typescript-eslint/types': 8.55.0
+      '@typescript-eslint/visitor-keys': 8.55.0
       debug: 4.4.3
       minimatch: 9.0.5
       semver: 7.7.3
       tinyglobby: 0.2.15
-      ts-api-utils: 2.1.0(typescript@5.5.4)
+      ts-api-utils: 2.4.0(typescript@5.5.4)
       typescript: 5.5.4
     transitivePeerDependencies:
       - supports-color
 
-  '@typescript-eslint/utils@8.48.1(eslint@9.9.1)(typescript@5.5.4)':
+  '@typescript-eslint/utils@8.55.0(eslint@10.0.0)(typescript@5.5.4)':
     dependencies:
-      '@eslint-community/eslint-utils': 4.9.0(eslint@9.9.1)
-      '@typescript-eslint/scope-manager': 8.48.1
-      '@typescript-eslint/types': 8.48.1
-      '@typescript-eslint/typescript-estree': 8.48.1(typescript@5.5.4)
-      eslint: 9.9.1
+      '@eslint-community/eslint-utils': 4.9.1(eslint@10.0.0)
+      '@typescript-eslint/scope-manager': 8.55.0
+      '@typescript-eslint/types': 8.55.0
+      '@typescript-eslint/typescript-estree': 8.55.0(typescript@5.5.4)
+      eslint: 10.0.0
       typescript: 5.5.4
     transitivePeerDependencies:
       - supports-color
 
-  '@typescript-eslint/visitor-keys@8.48.1':
+  '@typescript-eslint/visitor-keys@8.55.0':
     dependencies:
-      '@typescript-eslint/types': 8.48.1
+      '@typescript-eslint/types': 8.55.0
       eslint-visitor-keys: 4.2.1
 
   '@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))':
@@ -3380,11 +3404,6 @@ snapshots:
 
   birpc@2.5.0: {}
 
-  brace-expansion@1.1.12:
-    dependencies:
-      balanced-match: 1.0.2
-      concat-map: 0.0.1
-
   brace-expansion@2.0.2:
     dependencies:
       balanced-match: 1.0.2
@@ -3401,8 +3420,6 @@ snapshots:
 
   cac@6.7.14: {}
 
-  callsites@3.1.0: {}
-
   chai@5.3.3:
     dependencies:
       assertion-error: 2.0.1
@@ -3411,11 +3428,6 @@ snapshots:
       loupe: 3.2.1
       pathval: 2.0.0
 
-  chalk@4.1.2:
-    dependencies:
-      ansi-styles: 4.3.0
-      supports-color: 7.2.0
-
   chardet@2.1.0: {}
 
   check-error@2.1.1: {}
@@ -3451,8 +3463,6 @@ snapshots:
 
   commondir@1.0.1: {}
 
-  concat-map@0.0.1: {}
-
   cross-spawn@7.0.6:
     dependencies:
       path-key: 3.1.1
@@ -3599,31 +3609,33 @@ snapshots:
 
   escape-string-regexp@4.0.0: {}
 
-  eslint-compat-utils@0.5.1(eslint@9.9.1):
+  eslint-compat-utils@0.5.1(eslint@10.0.0):
     dependencies:
-      eslint: 9.9.1
+      eslint: 10.0.0
       semver: 7.7.3
 
-  eslint-config-prettier@9.1.0(eslint@9.9.1):
+  eslint-config-prettier@9.1.0(eslint@10.0.0):
     dependencies:
-      eslint: 9.9.1
+      eslint: 10.0.0
 
-  eslint-plugin-es-x@7.8.0(eslint@9.9.1):
+  eslint-plugin-es-x@7.8.0(eslint@10.0.0):
     dependencies:
-      '@eslint-community/eslint-utils': 4.9.0(eslint@9.9.1)
+      '@eslint-community/eslint-utils': 4.9.1(eslint@10.0.0)
       '@eslint-community/regexpp': 4.12.2
-      eslint: 9.9.1
-      eslint-compat-utils: 0.5.1(eslint@9.9.1)
+      eslint: 10.0.0
+      eslint-compat-utils: 0.5.1(eslint@10.0.0)
 
-  eslint-plugin-lube@0.4.3: {}
+  eslint-plugin-lube@0.5.1(eslint@10.0.0):
+    dependencies:
+      eslint: 10.0.0
 
-  eslint-plugin-n@17.16.1(eslint@9.9.1)(typescript@5.5.4):
+  eslint-plugin-n@17.16.1(eslint@10.0.0)(typescript@5.5.4):
     dependencies:
-      '@eslint-community/eslint-utils': 4.9.0(eslint@9.9.1)
-      '@typescript-eslint/utils': 8.48.1(eslint@9.9.1)(typescript@5.5.4)
+      '@eslint-community/eslint-utils': 4.9.1(eslint@10.0.0)
+      '@typescript-eslint/utils': 8.55.0(eslint@10.0.0)(typescript@5.5.4)
       enhanced-resolve: 5.18.3
-      eslint: 9.9.1
-      eslint-plugin-es-x: 7.8.0(eslint@9.9.1)
+      eslint: 10.0.0
+      eslint-plugin-es-x: 7.8.0(eslint@10.0.0)
       get-tsconfig: 4.13.0
       globals: 15.15.0
       ignore: 5.3.2
@@ -3634,11 +3646,11 @@ snapshots:
       - supports-color
       - typescript
 
-  eslint-plugin-svelte@3.11.0(eslint@9.9.1)(svelte@packages+svelte):
+  eslint-plugin-svelte@3.15.0(eslint@10.0.0)(svelte@packages+svelte):
     dependencies:
-      '@eslint-community/eslint-utils': 4.9.0(eslint@9.9.1)
+      '@eslint-community/eslint-utils': 4.9.1(eslint@10.0.0)
       '@jridgewell/sourcemap-codec': 1.5.0
-      eslint: 9.9.1
+      eslint: 10.0.0
       esutils: 2.0.3
       globals: 16.3.0
       known-css-properties: 0.37.0
@@ -3646,7 +3658,7 @@ snapshots:
       postcss-load-config: 3.1.4(postcss@8.5.6)
       postcss-safe-parser: 7.0.1(postcss@8.5.6)
       semver: 7.7.3
-      svelte-eslint-parser: 1.3.0(svelte@packages+svelte)
+      svelte-eslint-parser: 1.4.1(svelte@packages+svelte)
     optionalDependencies:
       svelte: link:packages/svelte
     transitivePeerDependencies:
@@ -3657,29 +3669,39 @@ snapshots:
       esrecurse: 4.3.0
       estraverse: 5.3.0
 
+  eslint-scope@9.1.0:
+    dependencies:
+      '@types/esrecurse': 4.3.1
+      '@types/estree': 1.0.8
+      esrecurse: 4.3.0
+      estraverse: 5.3.0
+
   eslint-visitor-keys@3.4.3: {}
 
   eslint-visitor-keys@4.2.1: {}
 
-  eslint@9.9.1:
+  eslint-visitor-keys@5.0.0: {}
+
+  eslint@10.0.0:
     dependencies:
-      '@eslint-community/eslint-utils': 4.9.0(eslint@9.9.1)
+      '@eslint-community/eslint-utils': 4.9.1(eslint@10.0.0)
       '@eslint-community/regexpp': 4.12.2
-      '@eslint/config-array': 0.18.0
-      '@eslint/eslintrc': 3.1.0
-      '@eslint/js': 9.9.1
+      '@eslint/config-array': 0.23.1
+      '@eslint/config-helpers': 0.5.2
+      '@eslint/core': 1.1.0
+      '@eslint/plugin-kit': 0.6.0
+      '@humanfs/node': 0.16.7
       '@humanwhocodes/module-importer': 1.0.1
-      '@humanwhocodes/retry': 0.3.0
-      '@nodelib/fs.walk': 1.2.8
+      '@humanwhocodes/retry': 0.4.3
+      '@types/estree': 1.0.8
       ajv: 6.12.6
-      chalk: 4.1.2
       cross-spawn: 7.0.6
       debug: 4.4.3
       escape-string-regexp: 4.0.0
-      eslint-scope: 8.4.0
-      eslint-visitor-keys: 4.2.1
-      espree: 10.1.0
-      esquery: 1.5.0
+      eslint-scope: 9.1.0
+      eslint-visitor-keys: 5.0.0
+      espree: 11.1.0
+      esquery: 1.7.0
       esutils: 2.0.3
       fast-deep-equal: 3.1.3
       file-entry-cache: 8.0.0
@@ -3688,15 +3710,10 @@ snapshots:
       ignore: 5.3.2
       imurmurhash: 0.1.4
       is-glob: 4.0.3
-      is-path-inside: 3.0.3
       json-stable-stringify-without-jsonify: 1.0.1
-      levn: 0.4.1
-      lodash.merge: 4.6.2
-      minimatch: 3.1.2
+      minimatch: 10.1.2
       natural-compare: 1.4.0
       optionator: 0.9.3
-      strip-ansi: 6.0.1
-      text-table: 0.2.0
     transitivePeerDependencies:
       - supports-color
 
@@ -3708,6 +3725,12 @@ snapshots:
       acorn-jsx: 5.3.2(acorn@8.15.0)
       eslint-visitor-keys: 4.2.1
 
+  espree@11.1.0:
+    dependencies:
+      acorn: 8.15.0
+      acorn-jsx: 5.3.2(acorn@8.15.0)
+      eslint-visitor-keys: 5.0.0
+
   espree@9.6.1:
     dependencies:
       acorn: 8.15.0
@@ -3716,7 +3739,7 @@ snapshots:
 
   esprima@4.0.1: {}
 
-  esquery@1.5.0:
+  esquery@1.7.0:
     dependencies:
       estraverse: 5.3.0
 
@@ -3841,12 +3864,12 @@ snapshots:
       package-json-from-dist: 1.0.0
       path-scurry: 1.11.1
 
-  globals@14.0.0: {}
-
   globals@15.15.0: {}
 
   globals@16.3.0: {}
 
+  globals@17.3.0: {}
+
   globby@11.1.0:
     dependencies:
       array-union: 2.1.0
@@ -3858,8 +3881,6 @@ snapshots:
 
   graceful-fs@4.2.11: {}
 
-  graphemer@1.4.0: {}
-
   has-flag@4.0.0: {}
 
   hasown@2.0.0:
@@ -3903,11 +3924,6 @@ snapshots:
   immutable@4.3.7:
     optional: true
 
-  import-fresh@3.3.0:
-    dependencies:
-      parent-module: 1.0.1
-      resolve-from: 4.0.0
-
   imurmurhash@0.1.4: {}
 
   is-binary-path@2.1.0:
@@ -3937,8 +3953,6 @@ snapshots:
 
   is-number@7.0.0: {}
 
-  is-path-inside@3.0.3: {}
-
   is-potential-custom-element-name@1.0.1: {}
 
   is-reference@1.2.1:
@@ -4102,8 +4116,6 @@ snapshots:
     dependencies:
       p-locate: 5.0.0
 
-  lodash.merge@4.6.2: {}
-
   lodash.startcase@4.4.0: {}
 
   loupe@3.2.1: {}
@@ -4137,9 +4149,9 @@ snapshots:
     dependencies:
       mime-db: 1.52.0
 
-  minimatch@3.1.2:
+  minimatch@10.1.2:
     dependencies:
-      brace-expansion: 1.1.12
+      '@isaacs/brace-expansion': 5.0.1
 
   minimatch@9.0.5:
     dependencies:
@@ -4216,10 +4228,6 @@ snapshots:
     dependencies:
       quansync: 0.2.11
 
-  parent-module@1.0.1:
-    dependencies:
-      callsites: 3.1.0
-
   parse5@7.1.2:
     dependencies:
       entities: 4.5.0
@@ -4327,8 +4335,6 @@ snapshots:
 
   regexparam@3.0.0: {}
 
-  resolve-from@4.0.0: {}
-
   resolve-from@5.0.0: {}
 
   resolve-pkg-maps@1.0.0: {}
@@ -4466,15 +4472,13 @@ snapshots:
 
   strip-bom@3.0.0: {}
 
-  strip-json-comments@3.1.1: {}
-
   supports-color@7.2.0:
     dependencies:
       has-flag: 4.0.0
 
   supports-preserve-symlinks-flag@1.0.0: {}
 
-  svelte-eslint-parser@1.3.0(svelte@packages+svelte):
+  svelte-eslint-parser@1.4.1(svelte@packages+svelte):
     dependencies:
       eslint-scope: 8.4.0
       eslint-visitor-keys: 4.2.1
@@ -4504,8 +4508,6 @@ snapshots:
       glob: 10.5.0
       minimatch: 9.0.5
 
-  text-table@0.2.0: {}
-
   tinybench@2.9.0: {}
 
   tinyexec@0.3.2: {}
@@ -4553,7 +4555,7 @@ snapshots:
     dependencies:
       typescript: 5.5.4
 
-  ts-api-utils@2.1.0(typescript@5.5.4):
+  ts-api-utils@2.4.0(typescript@5.5.4):
     dependencies:
       typescript: 5.5.4
 
@@ -4566,13 +4568,13 @@ snapshots:
     dependencies:
       prelude-ls: 1.2.1
 
-  typescript-eslint@8.48.1(eslint@9.9.1)(typescript@5.5.4):
+  typescript-eslint@8.55.0(eslint@10.0.0)(typescript@5.5.4):
     dependencies:
-      '@typescript-eslint/eslint-plugin': 8.48.1(@typescript-eslint/parser@8.48.1(eslint@9.9.1)(typescript@5.5.4))(eslint@9.9.1)(typescript@5.5.4)
-      '@typescript-eslint/parser': 8.48.1(eslint@9.9.1)(typescript@5.5.4)
-      '@typescript-eslint/typescript-estree': 8.48.1(typescript@5.5.4)
-      '@typescript-eslint/utils': 8.48.1(eslint@9.9.1)(typescript@5.5.4)
-      eslint: 9.9.1
+      '@typescript-eslint/eslint-plugin': 8.55.0(@typescript-eslint/parser@8.55.0(eslint@10.0.0)(typescript@5.5.4))(eslint@10.0.0)(typescript@5.5.4)
+      '@typescript-eslint/parser': 8.55.0(eslint@10.0.0)(typescript@5.5.4)
+      '@typescript-eslint/typescript-estree': 8.55.0(typescript@5.5.4)
+      '@typescript-eslint/utils': 8.55.0(eslint@10.0.0)(typescript@5.5.4)
+      eslint: 10.0.0
       typescript: 5.5.4
     transitivePeerDependencies:
       - supports-color