From 6c97a78049ccc706076e8b962d482c7a1fa27650 Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Thu, 10 Apr 2025 13:29:40 +0200
Subject: [PATCH 01/27] fix: prevent ownership warnings if the fallback of a
 bindable is used (#15720)

* fix: prevent ownership warnings if the fallback of a bindable is used

* fix: filter out symbol from own keys

* fix: don't create sources for `BINDABLE_FALLBACK_SYMBOL`

* fix: use strategy suggested by actually competent person aka @dummdidumm

* chore: rename function
---
 .changeset/wise-turkeys-yell.md               |  5 ++++
 .../src/internal/client/dev/ownership.js      | 12 ++++++----
 .../src/internal/client/reactivity/props.js   |  2 +-
 .../Child.svelte                              |  5 ++++
 .../Parent.svelte                             |  7 ++++++
 .../_config.js                                | 11 +++++++++
 .../main.svelte                               |  5 ++++
 .../Parent.svelte                             |  8 +++++++
 .../_config.js                                | 23 +++++++++++++++++++
 .../main.svelte                               |  5 ++++
 10 files changed, 78 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/wise-turkeys-yell.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/ownership-invalid-binding-bindable-fallback/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/ownership-invalid-binding-bindable-fallback/Parent.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/ownership-invalid-binding-bindable-fallback/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/ownership-invalid-binding-bindable-fallback/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-bindable-fallback/Parent.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-bindable-fallback/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-bindable-fallback/main.svelte

diff --git a/.changeset/wise-turkeys-yell.md b/.changeset/wise-turkeys-yell.md
new file mode 100644
index 0000000000..cd5e103de3
--- /dev/null
+++ b/.changeset/wise-turkeys-yell.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: prevent ownership warnings if the fallback of a bindable is used
diff --git a/packages/svelte/src/internal/client/dev/ownership.js b/packages/svelte/src/internal/client/dev/ownership.js
index e28a40dd77..108c7adf92 100644
--- a/packages/svelte/src/internal/client/dev/ownership.js
+++ b/packages/svelte/src/internal/client/dev/ownership.js
@@ -27,7 +27,7 @@ export function create_ownership_validator(props) {
 		 */
 		mutation: (prop, path, result, line, column) => {
 			const name = path[0];
-			if (is_bound(props, name) || !parent) {
+			if (is_bound_or_unset(props, name) || !parent) {
 				return result;
 			}
 
@@ -52,7 +52,7 @@ export function create_ownership_validator(props) {
 		 * @param {() => any} value
 		 */
 		binding: (key, child_component, value) => {
-			if (!is_bound(props, key) && parent && value()?.[STATE_SYMBOL]) {
+			if (!is_bound_or_unset(props, key) && parent && value()?.[STATE_SYMBOL]) {
 				w.ownership_invalid_binding(
 					component[FILENAME],
 					key,
@@ -68,9 +68,13 @@ export function create_ownership_validator(props) {
  * @param {Record<string, any>} props
  * @param {string} prop_name
  */
-function is_bound(props, prop_name) {
+function is_bound_or_unset(props, prop_name) {
 	// Can be the case when someone does `mount(Component, props)` with `let props = $state({...})`
 	// or `createClassComponent(Component, props)`
 	const is_entry_props = STATE_SYMBOL in props || LEGACY_PROPS in props;
-	return !!get_descriptor(props, prop_name)?.set || (is_entry_props && prop_name in props);
+	return (
+		!!get_descriptor(props, prop_name)?.set ||
+		(is_entry_props && prop_name in props) ||
+		!(prop_name in props)
+	);
 }
diff --git a/packages/svelte/src/internal/client/reactivity/props.js b/packages/svelte/src/internal/client/reactivity/props.js
index bd85b14df0..341d7c768a 100644
--- a/packages/svelte/src/internal/client/reactivity/props.js
+++ b/packages/svelte/src/internal/client/reactivity/props.js
@@ -7,7 +7,7 @@ import {
 	PROPS_IS_RUNES,
 	PROPS_IS_UPDATED
 } from '../../../constants.js';
-import { get_descriptor, is_function } from '../../shared/utils.js';
+import { define_property, get_descriptor, is_function } from '../../shared/utils.js';
 import { mutable_source, set, source, update } from './sources.js';
 import { derived, derived_safe_equal } from './deriveds.js';
 import { get, captured_signals, untrack } from '../runtime.js';
diff --git a/packages/svelte/tests/runtime-runes/samples/ownership-invalid-binding-bindable-fallback/Child.svelte b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-binding-bindable-fallback/Child.svelte
new file mode 100644
index 0000000000..78b82caed9
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-binding-bindable-fallback/Child.svelte
@@ -0,0 +1,5 @@
+<script>
+	const { test = $bindable() } = $props();
+</script>
+
+{test}
diff --git a/packages/svelte/tests/runtime-runes/samples/ownership-invalid-binding-bindable-fallback/Parent.svelte b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-binding-bindable-fallback/Parent.svelte
new file mode 100644
index 0000000000..7bfb17aa64
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-binding-bindable-fallback/Parent.svelte
@@ -0,0 +1,7 @@
+<script>
+	import Child from './Child.svelte';
+
+	let { test = $bindable({}) } = $props();
+</script>
+
+<Child bind:test />
diff --git a/packages/svelte/tests/runtime-runes/samples/ownership-invalid-binding-bindable-fallback/_config.js b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-binding-bindable-fallback/_config.js
new file mode 100644
index 0000000000..e93067eb9d
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-binding-bindable-fallback/_config.js
@@ -0,0 +1,11 @@
+import { test } from '../../test';
+
+export default test({
+	mode: ['client'],
+	compileOptions: {
+		dev: true
+	},
+	async test({ warnings, assert }) {
+		assert.deepEqual(warnings, []);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/ownership-invalid-binding-bindable-fallback/main.svelte b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-binding-bindable-fallback/main.svelte
new file mode 100644
index 0000000000..282afb1771
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-binding-bindable-fallback/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Parent from './Parent.svelte';
+</script>
+
+<Parent />
diff --git a/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-bindable-fallback/Parent.svelte b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-bindable-fallback/Parent.svelte
new file mode 100644
index 0000000000..7d6b248da7
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-bindable-fallback/Parent.svelte
@@ -0,0 +1,8 @@
+<script>
+	let { test = $bindable({}) } = $props();
+</script>
+
+<button onclick={()=>test = {}}></button>
+<button onclick={()=>test.test = {}}></button>
+
+{test}
\ No newline at end of file
diff --git a/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-bindable-fallback/_config.js b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-bindable-fallback/_config.js
new file mode 100644
index 0000000000..9b4e3479ea
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-bindable-fallback/_config.js
@@ -0,0 +1,23 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['client'],
+	compileOptions: {
+		dev: true
+	},
+	async test({ warnings, assert, target }) {
+		const [btn, btn2] = target.querySelectorAll('button');
+		flushSync(() => {
+			btn2.click();
+		});
+		assert.deepEqual(warnings, []);
+		flushSync(() => {
+			btn.click();
+		});
+		flushSync(() => {
+			btn2.click();
+		});
+		assert.deepEqual(warnings, []);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-bindable-fallback/main.svelte b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-bindable-fallback/main.svelte
new file mode 100644
index 0000000000..282afb1771
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/ownership-invalid-mutation-bindable-fallback/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Parent from './Parent.svelte';
+</script>
+
+<Parent />

From 6d195f0350c5e46da0012525f92654c62257402e Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Thu, 10 Apr 2025 08:19:07 -0400
Subject: [PATCH 02/27] fix: handle hydration mismatches in await blocks
 (#15708)

* failing test for #15704

* handle hydration mismatches in await blocks

* DRY out

* changeset

* update test
---
 .changeset/wild-carrots-eat.md                |  5 ++++
 .../3-transform/server/visitors/AwaitBlock.js | 10 ++-----
 packages/svelte/src/constants.js              |  1 +
 .../src/internal/client/dom/blocks/await.js   | 29 +++++++++++++++++--
 packages/svelte/src/internal/server/index.js  |  7 +++--
 .../await-hydrate-maybe-promise/_config.js    | 23 +++++++++++++++
 .../await-hydrate-maybe-promise/main.svelte   | 25 ++++++++++++++++
 .../_expected/server/index.svelte.js          |  6 ++--
 8 files changed, 92 insertions(+), 14 deletions(-)
 create mode 100644 .changeset/wild-carrots-eat.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/await-hydrate-maybe-promise/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/await-hydrate-maybe-promise/main.svelte

diff --git a/.changeset/wild-carrots-eat.md b/.changeset/wild-carrots-eat.md
new file mode 100644
index 0000000000..23b55f945c
--- /dev/null
+++ b/.changeset/wild-carrots-eat.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: handle hydration mismatches in await blocks
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 8fc82b8905..2aa534d257 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 '../../../../utils/builders.js';
-import { empty_comment } from './shared/utils.js';
+import { block_close } from './shared/utils.js';
 
 /**
  * @param {AST.AwaitBlock} node
@@ -10,10 +10,10 @@ import { empty_comment } from './shared/utils.js';
  */
 export function AwaitBlock(node, context) {
 	context.state.template.push(
-		empty_comment,
 		b.stmt(
 			b.call(
 				'$.await',
+				b.id('$$payload'),
 				/** @type {Expression} */ (context.visit(node.expression)),
 				b.thunk(
 					node.pending ? /** @type {BlockStatement} */ (context.visit(node.pending)) : b.block([])
@@ -21,13 +21,9 @@ export function AwaitBlock(node, context) {
 				b.arrow(
 					node.value ? [/** @type {Pattern} */ (context.visit(node.value))] : [],
 					node.then ? /** @type {BlockStatement} */ (context.visit(node.then)) : b.block([])
-				),
-				b.arrow(
-					node.error ? [/** @type {Pattern} */ (context.visit(node.error))] : [],
-					node.catch ? /** @type {BlockStatement} */ (context.visit(node.catch)) : b.block([])
 				)
 			)
 		),
-		empty_comment
+		block_close
 	);
 }
diff --git a/packages/svelte/src/constants.js b/packages/svelte/src/constants.js
index 8861e440fc..6ea407d448 100644
--- a/packages/svelte/src/constants.js
+++ b/packages/svelte/src/constants.js
@@ -22,6 +22,7 @@ export const HYDRATION_START = '[';
 /** used to indicate that an `{:else}...` block was rendered */
 export const HYDRATION_START_ELSE = '[!';
 export const HYDRATION_END = ']';
+export const HYDRATION_AWAIT_THEN = '!';
 export const HYDRATION_ERROR = {};
 
 export const ELEMENT_IS_NAMESPACED = 1;
diff --git a/packages/svelte/src/internal/client/dom/blocks/await.js b/packages/svelte/src/internal/client/dom/blocks/await.js
index 2e3d229779..99bdc0000c 100644
--- a/packages/svelte/src/internal/client/dom/blocks/await.js
+++ b/packages/svelte/src/internal/client/dom/blocks/await.js
@@ -4,9 +4,16 @@ import { is_promise } from '../../../shared/utils.js';
 import { block, branch, pause_effect, resume_effect } from '../../reactivity/effects.js';
 import { internal_set, mutable_source, source } from '../../reactivity/sources.js';
 import { flushSync, set_active_effect, set_active_reaction } from '../../runtime.js';
-import { hydrate_next, hydrate_node, hydrating } from '../hydration.js';
+import {
+	hydrate_next,
+	hydrate_node,
+	hydrating,
+	remove_nodes,
+	set_hydrate_node,
+	set_hydrating
+} from '../hydration.js';
 import { queue_micro_task } from '../task.js';
-import { UNINITIALIZED } from '../../../../constants.js';
+import { HYDRATION_START_ELSE, UNINITIALIZED } from '../../../../constants.js';
 import {
 	component_context,
 	is_runes,
@@ -113,6 +120,19 @@ export function await_block(node, get_input, pending_fn, then_fn, catch_fn) {
 	var effect = block(() => {
 		if (input === (input = get_input())) return;
 
+		/** Whether or not there was a hydration mismatch. Needs to be a `let` or else it isn't treeshaken out */
+		// @ts-ignore coercing `anchor` to a `Comment` causes TypeScript and Prettier to fight
+		let mismatch = hydrating && is_promise(input) === (anchor.data === HYDRATION_START_ELSE);
+
+		if (mismatch) {
+			// Hydration mismatch: remove everything inside the anchor and start fresh
+			anchor = remove_nodes();
+
+			set_hydrate_node(anchor);
+			set_hydrating(false);
+			mismatch = true;
+		}
+
 		if (is_promise(input)) {
 			var promise = input;
 
@@ -155,6 +175,11 @@ export function await_block(node, get_input, pending_fn, then_fn, catch_fn) {
 			update(THEN, false);
 		}
 
+		if (mismatch) {
+			// continue in hydration mode
+			set_hydrating(true);
+		}
+
 		// Set the input to something else, in order to disable the promise callbacks
 		return () => (input = UNINITIALIZED);
 	});
diff --git a/packages/svelte/src/internal/server/index.js b/packages/svelte/src/internal/server/index.js
index bf36a595d8..ff34c07132 100644
--- a/packages/svelte/src/internal/server/index.js
+++ b/packages/svelte/src/internal/server/index.js
@@ -13,7 +13,7 @@ import {
 import { escape_html } from '../../escaping.js';
 import { DEV } from 'esm-env';
 import { current_component, pop, push } from './context.js';
-import { EMPTY_COMMENT, BLOCK_CLOSE, BLOCK_OPEN } from './hydration.js';
+import { EMPTY_COMMENT, BLOCK_CLOSE, BLOCK_OPEN, BLOCK_OPEN_ELSE } from './hydration.js';
 import { validate_store } from '../shared/validate.js';
 import { is_boolean_attribute, is_raw_text_element, is_void } from '../../utils.js';
 import { reset_elements } from './dev.js';
@@ -474,18 +474,21 @@ export function bind_props(props_parent, props_now) {
 
 /**
  * @template V
+ * @param {Payload} payload
  * @param {Promise<V>} promise
  * @param {null | (() => void)} pending_fn
  * @param {(value: V) => void} then_fn
  * @returns {void}
  */
-function await_block(promise, pending_fn, then_fn) {
+function await_block(payload, promise, pending_fn, then_fn) {
 	if (is_promise(promise)) {
+		payload.out += BLOCK_OPEN;
 		promise.then(null, noop);
 		if (pending_fn !== null) {
 			pending_fn();
 		}
 	} else if (then_fn !== null) {
+		payload.out += BLOCK_OPEN_ELSE;
 		then_fn(promise);
 	}
 }
diff --git a/packages/svelte/tests/runtime-runes/samples/await-hydrate-maybe-promise/_config.js b/packages/svelte/tests/runtime-runes/samples/await-hydrate-maybe-promise/_config.js
new file mode 100644
index 0000000000..f81b41d41a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/await-hydrate-maybe-promise/_config.js
@@ -0,0 +1,23 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	ssrHtml: '<button>fulfil</button><p>42</p><hr><p>loading...</p>',
+	html: '<button>fulfil</button><p>loading...</p><hr><p>42</p>',
+
+	props: {
+		browser: true
+	},
+
+	server_props: {
+		browser: false
+	},
+
+	async test({ assert, target }) {
+		const button = target.querySelector('button');
+
+		flushSync(() => button?.click());
+		await Promise.resolve();
+		assert.htmlEqual(target.innerHTML, '<button>fulfil</button><p>42</p><hr><p>42</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/await-hydrate-maybe-promise/main.svelte b/packages/svelte/tests/runtime-runes/samples/await-hydrate-maybe-promise/main.svelte
new file mode 100644
index 0000000000..d8d0cd4027
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/await-hydrate-maybe-promise/main.svelte
@@ -0,0 +1,25 @@
+<script>
+	let { browser } = $props();
+
+	let fulfil;
+	let promise = new Promise((f) => (fulfil = f));
+
+	let a = browser ? promise : 42;
+	let b = browser ? 42 : promise;
+</script>
+
+<button onclick={() => fulfil(42)}>fulfil</button>
+
+{#await a}
+	{#if true}<p>loading...</p>{/if}
+{:then a}
+	<p>{a}</p>
+{/await}
+
+<hr>
+
+{#await b}
+	{#if true}<p>loading...</p>{/if}
+{:then b}
+	<p>{b}</p>
+{/await}
diff --git a/packages/svelte/tests/snapshot/samples/await-block-scope/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/await-block-scope/_expected/server/index.svelte.js
index 012789a550..4b6e32d58e 100644
--- a/packages/svelte/tests/snapshot/samples/await-block-scope/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/await-block-scope/_expected/server/index.svelte.js
@@ -8,7 +8,7 @@ export default function Await_block_scope($$payload) {
 		counter.count += 1;
 	}
 
-	$$payload.out += `<button>clicks: ${$.escape(counter.count)}</button> <!---->`;
-	$.await(promise, () => {}, (counter) => {}, () => {});
-	$$payload.out += `<!----> ${$.escape(counter.count)}`;
+	$$payload.out += `<button>clicks: ${$.escape(counter.count)}</button> `;
+	$.await($$payload, promise, () => {}, (counter) => {});
+	$$payload.out += `<!--]--> ${$.escape(counter.count)}`;
 }
\ No newline at end of file

From c2c83b67f3470fa27afe998e079a48de47b7d9c1 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Thu, 10 Apr 2025 15:39:50 -0400
Subject: [PATCH 03/27] Version Packages (#15726)

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

diff --git a/.changeset/wild-carrots-eat.md b/.changeset/wild-carrots-eat.md
deleted file mode 100644
index 23b55f945c..0000000000
--- a/.changeset/wild-carrots-eat.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: handle hydration mismatches in await blocks
diff --git a/.changeset/wise-turkeys-yell.md b/.changeset/wise-turkeys-yell.md
deleted file mode 100644
index cd5e103de3..0000000000
--- a/.changeset/wise-turkeys-yell.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: prevent ownership warnings if the fallback of a bindable is used
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 6f999f381e..3066c19bce 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,13 @@
 # svelte
 
+## 5.25.11
+
+### Patch Changes
+
+- fix: handle hydration mismatches in await blocks ([#15708](https://github.com/sveltejs/svelte/pull/15708))
+
+- fix: prevent ownership warnings if the fallback of a bindable is used ([#15720](https://github.com/sveltejs/svelte/pull/15720))
+
 ## 5.25.10
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index b9f434e688..187d3aaa2c 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": "5.25.10",
+  "version": "5.25.11",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 2ea9890df9..cc5f8f775c 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 = '5.25.10';
+export const VERSION = '5.25.11';
 export const PUBLIC_VERSION = '5';

From 9cafdd89d0e8f2fb0ce02e5b5112498218d4f2b5 Mon Sep 17 00:00:00 2001
From: Dominic Gannaway <trueadm@users.noreply.github.com>
Date: Thu, 10 Apr 2025 22:18:38 +0100
Subject: [PATCH 04/27] fix: improve internal_set versioning mechanic (#15724)

---
 .changeset/pretty-planes-visit.md               |  5 +++++
 .../src/internal/client/reactivity/sources.js   |  3 ++-
 .../samples/writable-derived-2/_config.js       |  7 +++++++
 .../samples/writable-derived-2/main.svelte      |  9 +++++++++
 .../samples/writable-derived-2/util.svelte.js   | 17 +++++++++++++++++
 5 files changed, 40 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/pretty-planes-visit.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/writable-derived-2/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/writable-derived-2/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/writable-derived-2/util.svelte.js

diff --git a/.changeset/pretty-planes-visit.md b/.changeset/pretty-planes-visit.md
new file mode 100644
index 0000000000..d2ee0cae2e
--- /dev/null
+++ b/.changeset/pretty-planes-visit.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: improve internal_set versioning mechanic
diff --git a/packages/svelte/src/internal/client/reactivity/sources.js b/packages/svelte/src/internal/client/reactivity/sources.js
index cae49c1832..27e8fd824d 100644
--- a/packages/svelte/src/internal/client/reactivity/sources.js
+++ b/packages/svelte/src/internal/client/reactivity/sources.js
@@ -162,7 +162,6 @@ export function internal_set(source, value) {
 		}
 
 		source.v = value;
-		source.wv = increment_write_version();
 
 		if (DEV && tracing_mode_flag) {
 			source.updated = get_stack('UpdatedAt');
@@ -180,6 +179,8 @@ export function internal_set(source, value) {
 			set_signal_status(source, (source.f & UNOWNED) === 0 ? CLEAN : MAYBE_DIRTY);
 		}
 
+		source.wv = increment_write_version();
+
 		mark_reactions(source, DIRTY);
 
 		// It's possible that the current reaction might not have up-to-date dependencies
diff --git a/packages/svelte/tests/runtime-runes/samples/writable-derived-2/_config.js b/packages/svelte/tests/runtime-runes/samples/writable-derived-2/_config.js
new file mode 100644
index 0000000000..fde3e7b1ea
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/writable-derived-2/_config.js
@@ -0,0 +1,7 @@
+import { test } from '../../test';
+
+export default test({
+	html: `true true`,
+
+	test({ assert, target, window }) {}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/writable-derived-2/main.svelte b/packages/svelte/tests/runtime-runes/samples/writable-derived-2/main.svelte
new file mode 100644
index 0000000000..741aa69125
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/writable-derived-2/main.svelte
@@ -0,0 +1,9 @@
+<script>
+	import { expect2, createAppState } from "./util.svelte.js"
+
+  const result = createAppState({ source: () => "wrong" });
+  result.onChange("right");
+  const expect1 = result.value === "right";
+</script>
+
+{expect1} {expect2}
diff --git a/packages/svelte/tests/runtime-runes/samples/writable-derived-2/util.svelte.js b/packages/svelte/tests/runtime-runes/samples/writable-derived-2/util.svelte.js
new file mode 100644
index 0000000000..8e862753ab
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/writable-derived-2/util.svelte.js
@@ -0,0 +1,17 @@
+export const createAppState = (options) => {
+	const source = $derived(options.source());
+	let value = $derived(source);
+
+	return {
+		get value() {
+			return value;
+		},
+		onChange(nextValue) {
+			value = nextValue;
+		}
+	};
+};
+
+const result = createAppState({ source: () => 'wrong' });
+result.onChange('right');
+export const expect2 = result.value === 'right';

From 73acf6e7f48957d39d9e261083d652e89bbc94c3 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Thu, 10 Apr 2025 17:26:25 -0400
Subject: [PATCH 05/27] nicer sandbox output (#15730)

---
 playgrounds/sandbox/run.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/playgrounds/sandbox/run.js b/playgrounds/sandbox/run.js
index 8fa2c2a2da..3a62286b24 100644
--- a/playgrounds/sandbox/run.js
+++ b/playgrounds/sandbox/run.js
@@ -56,7 +56,7 @@ for (const generate of /** @type {const} */ (['client', 'server'])) {
 			});
 
 			write(
-				`${cwd}/output/${file}.json`,
+				`${cwd}/output/ast/${file}.json`,
 				JSON.stringify(
 					ast,
 					(key, value) => (typeof value === 'bigint' ? ['BigInt', value.toString()] : value),
@@ -66,7 +66,7 @@ for (const generate of /** @type {const} */ (['client', 'server'])) {
 
 			try {
 				const migrated = migrate(source);
-				write(`${cwd}/output/${file}.migrated.svelte`, migrated.code);
+				write(`${cwd}/output/migrated/${file}`, migrated.code);
 			} catch (e) {
 				console.warn(`Error migrating ${file}`, e);
 			}

From 0d233e58cf4472cb922118ad76509500273f0d60 Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Fri, 11 Apr 2025 00:17:22 +0200
Subject: [PATCH 06/27] fix: don't transform reassigned state in labeled
 statement in `$derived` (#15725)

* fix: don't transform reassigned state in labeled statement in `$derived`

* fix type so optional chaining is unnecessary

* drive-by tidy up

* drive-by tidy up

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/weak-doors-yell.md                 |  5 ++
 packages/svelte/src/compiler/migrate/index.js | 72 +++++++++----------
 .../input.svelte                              |  6 ++
 .../output.svelte                             | 10 +++
 4 files changed, 57 insertions(+), 36 deletions(-)
 create mode 100644 .changeset/weak-doors-yell.md
 create mode 100644 packages/svelte/tests/migrate/samples/labeled-statement-reassign-state/input.svelte
 create mode 100644 packages/svelte/tests/migrate/samples/labeled-statement-reassign-state/output.svelte

diff --git a/.changeset/weak-doors-yell.md b/.changeset/weak-doors-yell.md
new file mode 100644
index 0000000000..1b21783435
--- /dev/null
+++ b/.changeset/weak-doors-yell.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: don't transform reassigned state in labeled statement in `$derived`
diff --git a/packages/svelte/src/compiler/migrate/index.js b/packages/svelte/src/compiler/migrate/index.js
index 9d79d88b23..523389a25a 100644
--- a/packages/svelte/src/compiler/migrate/index.js
+++ b/packages/svelte/src/compiler/migrate/index.js
@@ -944,54 +944,53 @@ const instance_script = {
 			node.body.type === 'ExpressionStatement' &&
 			node.body.expression.type === 'AssignmentExpression'
 		) {
-			const ids = extract_identifiers(node.body.expression.left);
-			const [, expression_ids] = extract_all_identifiers_from_expression(
-				node.body.expression.right
-			);
-			const bindings = ids.map((id) => state.scope.get(id.name));
-			const reassigned_bindings = bindings.filter((b) => b?.reassigned);
+			const { left, right } = node.body.expression;
 
-			if (
-				node.body.expression.right.type !== 'Literal' &&
-				!bindings.some((b) => b?.kind === 'store_sub') &&
-				node.body.expression.left.type !== 'MemberExpression'
-			) {
-				let { start, end } = /** @type {{ start: number, end: number }} */ (
-					node.body.expression.right
-				);
+			const ids = extract_identifiers(left);
+			const [, expression_ids] = extract_all_identifiers_from_expression(right);
+			const bindings = ids.map((id) => /** @type {Binding} */ (state.scope.get(id.name)));
 
-				check_rune_binding('derived');
+			if (bindings.every((b) => b.kind === 'legacy_reactive')) {
+				if (
+					right.type !== 'Literal' &&
+					bindings.every((b) => b.kind !== 'store_sub') &&
+					left.type !== 'MemberExpression'
+				) {
+					let { start, end } = /** @type {{ start: number, end: number }} */ (right);
 
-				// $derived
-				state.str.update(
-					/** @type {number} */ (node.start),
-					/** @type {number} */ (node.body.expression.start),
-					'let '
-				);
+					check_rune_binding('derived');
 
-				if (node.body.expression.right.type === 'SequenceExpression') {
-					while (state.str.original[start] !== '(') start -= 1;
-					while (state.str.original[end - 1] !== ')') end += 1;
-				}
+					// $derived
+					state.str.update(
+						/** @type {number} */ (node.start),
+						/** @type {number} */ (node.body.expression.start),
+						'let '
+					);
+
+					if (right.type === 'SequenceExpression') {
+						while (state.str.original[start] !== '(') start -= 1;
+						while (state.str.original[end - 1] !== ')') end += 1;
+					}
+
+					state.str.prependRight(start, `$derived(`);
 
-				state.str.prependRight(start, `$derived(`);
+					// in a case like `$: ({ a } = b())`, there's already a trailing parenthesis.
+					// otherwise, we need to add one
+					if (state.str.original[/** @type {number} */ (node.body.start)] !== '(') {
+						state.str.appendLeft(end, `)`);
+					}
 
-				// in a case like `$: ({ a } = b())`, there's already a trailing parenthesis.
-				// otherwise, we need to add one
-				if (state.str.original[/** @type {number} */ (node.body.start)] !== '(') {
-					state.str.appendLeft(end, `)`);
+					return;
 				}
 
-				return;
-			} else {
-				for (const binding of reassigned_bindings) {
-					if (binding && (ids.includes(binding.node) || expression_ids.length === 0)) {
+				for (const binding of bindings) {
+					if (binding.reassigned && (ids.includes(binding.node) || expression_ids.length === 0)) {
 						check_rune_binding('state');
 						const init =
 							binding.kind === 'state'
 								? ' = $state()'
 								: expression_ids.length === 0
-									? ` = $state(${state.str.original.substring(/** @type {number} */ (node.body.expression.right.start), node.body.expression.right.end)})`
+									? ` = $state(${state.str.original.substring(/** @type {number} */ (right.start), right.end)})`
 									: '';
 						// implicitly-declared variable which we need to make explicit
 						state.str.prependLeft(
@@ -1000,7 +999,8 @@ const instance_script = {
 						);
 					}
 				}
-				if (expression_ids.length === 0 && !bindings.some((b) => b?.kind === 'store_sub')) {
+
+				if (expression_ids.length === 0 && bindings.every((b) => b.kind !== 'store_sub')) {
 					state.str.remove(/** @type {number} */ (node.start), /** @type {number} */ (node.end));
 					return;
 				}
diff --git a/packages/svelte/tests/migrate/samples/labeled-statement-reassign-state/input.svelte b/packages/svelte/tests/migrate/samples/labeled-statement-reassign-state/input.svelte
new file mode 100644
index 0000000000..0b5c13d889
--- /dev/null
+++ b/packages/svelte/tests/migrate/samples/labeled-statement-reassign-state/input.svelte
@@ -0,0 +1,6 @@
+<script>
+	let something = '123';
+	
+	let foo = false;
+	$: foo = !!something;
+</script>
\ No newline at end of file
diff --git a/packages/svelte/tests/migrate/samples/labeled-statement-reassign-state/output.svelte b/packages/svelte/tests/migrate/samples/labeled-statement-reassign-state/output.svelte
new file mode 100644
index 0000000000..c2b36a6e30
--- /dev/null
+++ b/packages/svelte/tests/migrate/samples/labeled-statement-reassign-state/output.svelte
@@ -0,0 +1,10 @@
+<script>
+	import { run } from 'svelte/legacy';
+
+	let something = '123';
+	
+	let foo = $state(false);
+	run(() => {
+		foo = !!something;
+	});
+</script>
\ No newline at end of file

From 0020e597e2137cdc8d6c913885978f0ccb966e3f Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Thu, 10 Apr 2025 18:39:23 -0400
Subject: [PATCH 07/27] Version Packages (#15729)

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

diff --git a/.changeset/pretty-planes-visit.md b/.changeset/pretty-planes-visit.md
deleted file mode 100644
index d2ee0cae2e..0000000000
--- a/.changeset/pretty-planes-visit.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: improve internal_set versioning mechanic
diff --git a/.changeset/weak-doors-yell.md b/.changeset/weak-doors-yell.md
deleted file mode 100644
index 1b21783435..0000000000
--- a/.changeset/weak-doors-yell.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: don't transform reassigned state in labeled statement in `$derived`
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 3066c19bce..f27a6640bd 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,13 @@
 # svelte
 
+## 5.25.12
+
+### Patch Changes
+
+- fix: improve internal_set versioning mechanic ([#15724](https://github.com/sveltejs/svelte/pull/15724))
+
+- fix: don't transform reassigned state in labeled statement in `$derived` ([#15725](https://github.com/sveltejs/svelte/pull/15725))
+
 ## 5.25.11
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 187d3aaa2c..67f6186fc7 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": "5.25.11",
+  "version": "5.25.12",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index cc5f8f775c..c554e9018c 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 = '5.25.11';
+export const VERSION = '5.25.12';
 export const PUBLIC_VERSION = '5';

From ec1d85c89e345529b9108b770c68cf89b808f3b0 Mon Sep 17 00:00:00 2001
From: ComputerGuy <63362464+Ocean-OS@users.noreply.github.com>
Date: Thu, 10 Apr 2025 16:50:05 -0700
Subject: [PATCH 08/27] fix: add snippet argument validation in dev (#15521)

* init

* fix

* make `Payload` a class

* doh

* lint

* tweak changeset

* fix

* only export things that should be available on $

* tweak message

* fix

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/bright-jeans-compare.md            |  5 ++
 .../98-reference/.generated/shared-errors.md  |  6 ++
 .../svelte/messages/shared-errors/errors.md   |  4 ++
 .../client/visitors/SnippetBlock.js           | 17 ++++-
 .../server/visitors/SnippetBlock.js           |  5 +-
 .../src/internal/client/dev/validation.js     | 15 +++++
 packages/svelte/src/internal/client/index.js  |  1 +
 .../src/internal/server/blocks/snippet.js     |  2 +-
 packages/svelte/src/internal/server/dev.js    | 13 +++-
 packages/svelte/src/internal/server/index.js  | 57 ++---------------
 .../svelte/src/internal/server/payload.js     | 64 +++++++++++++++++++
 .../svelte/src/internal/server/types.d.ts     | 13 ----
 packages/svelte/src/internal/shared/errors.js | 15 +++++
 13 files changed, 147 insertions(+), 70 deletions(-)
 create mode 100644 .changeset/bright-jeans-compare.md
 create mode 100644 packages/svelte/src/internal/client/dev/validation.js
 create mode 100644 packages/svelte/src/internal/server/payload.js

diff --git a/.changeset/bright-jeans-compare.md b/.changeset/bright-jeans-compare.md
new file mode 100644
index 0000000000..eaec658e03
--- /dev/null
+++ b/.changeset/bright-jeans-compare.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: add snippet argument validation in dev
diff --git a/documentation/docs/98-reference/.generated/shared-errors.md b/documentation/docs/98-reference/.generated/shared-errors.md
index 0102aafcbc..4c81d7b894 100644
--- a/documentation/docs/98-reference/.generated/shared-errors.md
+++ b/documentation/docs/98-reference/.generated/shared-errors.md
@@ -30,6 +30,12 @@ This error would be thrown in a setup like this:
 
 Here, `List.svelte` is using `{@render children(item)` which means it expects `Parent.svelte` to use snippets. Instead, `Parent.svelte` uses the deprecated `let:` directive. This combination of APIs is incompatible, hence the error.
 
+### invalid_snippet_arguments
+
+```
+A snippet function was passed invalid arguments. Snippets should only be instantiated via `{@render ...}`
+```
+
 ### lifecycle_outside_component
 
 ```
diff --git a/packages/svelte/messages/shared-errors/errors.md b/packages/svelte/messages/shared-errors/errors.md
index 8b4c61303a..20f3d193d9 100644
--- a/packages/svelte/messages/shared-errors/errors.md
+++ b/packages/svelte/messages/shared-errors/errors.md
@@ -26,6 +26,10 @@ This error would be thrown in a setup like this:
 
 Here, `List.svelte` is using `{@render children(item)` which means it expects `Parent.svelte` to use snippets. Instead, `Parent.svelte` uses the deprecated `let:` directive. This combination of APIs is incompatible, hence the error.
 
+## invalid_snippet_arguments
+
+> A snippet function was passed invalid arguments. Snippets should only be instantiated via `{@render ...}`
+
 ## lifecycle_outside_component
 
 > `%name%(...)` can only be used during component initialisation
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 7a0d6981b5..7eb043aa5d 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
@@ -1,4 +1,4 @@
-/** @import { BlockStatement, Expression, Identifier, Pattern, Statement } from 'estree' */
+/** @import { AssignmentPattern, BlockStatement, Expression, Identifier, Statement } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types' */
 import { dev } from '../../../../state.js';
@@ -12,7 +12,7 @@ import { get_value } from './shared/declarations.js';
  */
 export function SnippetBlock(node, context) {
 	// TODO hoist where possible
-	/** @type {Pattern[]} */
+	/** @type {(Identifier | AssignmentPattern)[]} */
 	const args = [b.id('$$anchor')];
 
 	/** @type {BlockStatement} */
@@ -66,7 +66,18 @@ export function SnippetBlock(node, context) {
 			}
 		}
 	}
-
+	if (dev) {
+		declarations.unshift(
+			b.stmt(
+				b.call(
+					'$.validate_snippet_args',
+					.../** @type {Identifier[]} */ (
+						args.map((arg) => (arg?.type === 'Identifier' ? arg : arg?.left))
+					)
+				)
+			)
+		);
+	}
 	body = b.block([
 		...declarations,
 		.../** @type {BlockStatement} */ (context.visit(node.body, child_state)).body
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SnippetBlock.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SnippetBlock.js
index eb83917927..cae3e7d79c 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SnippetBlock.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SnippetBlock.js
@@ -1,6 +1,7 @@
 /** @import { BlockStatement } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types.js' */
+import { dev } from '../../../../state.js';
 import * as b from '../../../../utils/builders.js';
 
 /**
@@ -13,7 +14,9 @@ export function SnippetBlock(node, context) {
 		[b.id('$$payload'), ...node.parameters],
 		/** @type {BlockStatement} */ (context.visit(node.body))
 	);
-
+	if (dev) {
+		fn.body.body.unshift(b.stmt(b.call('$.validate_snippet_args', b.id('$$payload'))));
+	}
 	// @ts-expect-error - TODO remove this hack once $$render_inner for legacy bindings is gone
 	fn.___snippet = true;
 
diff --git a/packages/svelte/src/internal/client/dev/validation.js b/packages/svelte/src/internal/client/dev/validation.js
new file mode 100644
index 0000000000..e41e4c4628
--- /dev/null
+++ b/packages/svelte/src/internal/client/dev/validation.js
@@ -0,0 +1,15 @@
+import { invalid_snippet_arguments } from '../../shared/errors.js';
+/**
+ * @param {Node} anchor
+ * @param {...(()=>any)[]} args
+ */
+export function validate_snippet_args(anchor, ...args) {
+	if (typeof anchor !== 'object' || !(anchor instanceof Node)) {
+		invalid_snippet_arguments();
+	}
+	for (let arg of args) {
+		if (typeof arg !== 'function') {
+			invalid_snippet_arguments();
+		}
+	}
+}
diff --git a/packages/svelte/src/internal/client/index.js b/packages/svelte/src/internal/client/index.js
index a865419c5f..e977bf3b0f 100644
--- a/packages/svelte/src/internal/client/index.js
+++ b/packages/svelte/src/internal/client/index.js
@@ -8,6 +8,7 @@ export { create_ownership_validator } from './dev/ownership.js';
 export { check_target, legacy_api } from './dev/legacy.js';
 export { trace } from './dev/tracing.js';
 export { inspect } from './dev/inspect.js';
+export { validate_snippet_args } from './dev/validation.js';
 export { await_block as await } from './dom/blocks/await.js';
 export { if_block as if } from './dom/blocks/if.js';
 export { key_block as key } from './dom/blocks/key.js';
diff --git a/packages/svelte/src/internal/server/blocks/snippet.js b/packages/svelte/src/internal/server/blocks/snippet.js
index 3c5e860790..9e96ae3430 100644
--- a/packages/svelte/src/internal/server/blocks/snippet.js
+++ b/packages/svelte/src/internal/server/blocks/snippet.js
@@ -1,5 +1,5 @@
 /** @import { Snippet } from 'svelte' */
-/** @import { Payload } from '#server' */
+/** @import { Payload } from '../payload' */
 /** @import { Getters } from '#shared' */
 
 /**
diff --git a/packages/svelte/src/internal/server/dev.js b/packages/svelte/src/internal/server/dev.js
index ecf4e67429..34849196b7 100644
--- a/packages/svelte/src/internal/server/dev.js
+++ b/packages/svelte/src/internal/server/dev.js
@@ -1,10 +1,12 @@
-/** @import { Component, Payload } from '#server' */
+/** @import { Component } from '#server' */
 import { FILENAME } from '../../constants.js';
 import {
 	is_tag_valid_with_ancestor,
 	is_tag_valid_with_parent
 } from '../../html-tree-validation.js';
 import { current_component } from './context.js';
+import { invalid_snippet_arguments } from '../shared/errors.js';
+import { Payload } from './payload.js';
 
 /**
  * @typedef {{
@@ -98,3 +100,12 @@ export function push_element(payload, tag, line, column) {
 export function pop_element() {
 	parent = /** @type {Element} */ (parent).parent;
 }
+
+/**
+ * @param {Payload} payload
+ */
+export function validate_snippet_args(payload) {
+	if (typeof payload !== 'object' || !(payload instanceof Payload)) {
+		invalid_snippet_arguments();
+	}
+}
diff --git a/packages/svelte/src/internal/server/index.js b/packages/svelte/src/internal/server/index.js
index ff34c07132..d711778a44 100644
--- a/packages/svelte/src/internal/server/index.js
+++ b/packages/svelte/src/internal/server/index.js
@@ -1,5 +1,5 @@
 /** @import { ComponentType, SvelteComponent } from 'svelte' */
-/** @import { Component, Payload, RenderOutput } from '#server' */
+/** @import { Component, RenderOutput } from '#server' */
 /** @import { Store } from '#shared' */
 export { FILENAME, HMR } from '../../constants.js';
 import { attr, clsx, to_class, to_style } from '../shared/attributes.js';
@@ -17,43 +17,13 @@ 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 { reset_elements } from './dev.js';
+import { Payload } from './payload.js';
 
 // https://html.spec.whatwg.org/multipage/syntax.html#attributes-2
 // https://infra.spec.whatwg.org/#noncharacter
 const INVALID_ATTR_NAME_CHAR_REGEX =
 	/[\s'">/=\u{FDD0}-\u{FDEF}\u{FFFE}\u{FFFF}\u{1FFFE}\u{1FFFF}\u{2FFFE}\u{2FFFF}\u{3FFFE}\u{3FFFF}\u{4FFFE}\u{4FFFF}\u{5FFFE}\u{5FFFF}\u{6FFFE}\u{6FFFF}\u{7FFFE}\u{7FFFF}\u{8FFFE}\u{8FFFF}\u{9FFFE}\u{9FFFF}\u{AFFFE}\u{AFFFF}\u{BFFFE}\u{BFFFF}\u{CFFFE}\u{CFFFF}\u{DFFFE}\u{DFFFF}\u{EFFFE}\u{EFFFF}\u{FFFFE}\u{FFFFF}\u{10FFFE}\u{10FFFF}]/u;
 
-/**
- * @param {Payload} to_copy
- * @returns {Payload}
- */
-export function copy_payload({ out, css, head, uid }) {
-	return {
-		out,
-		css: new Set(css),
-		head: {
-			title: head.title,
-			out: head.out,
-			css: new Set(head.css),
-			uid: head.uid
-		},
-		uid
-	};
-}
-
-/**
- * Assigns second payload to first
- * @param {Payload} p1
- * @param {Payload} p2
- * @returns {void}
- */
-export function assign_payload(p1, p2) {
-	p1.out = p2.out;
-	p1.css = p2.css;
-	p1.head = p2.head;
-	p1.uid = p2.uid;
-}
-
 /**
  * @param {Payload} payload
  * @param {string} tag
@@ -87,16 +57,6 @@ export function element(payload, tag, attributes_fn = noop, children_fn = noop)
  */
 export let on_destroy = [];
 
-/**
- * Creates an ID generator
- * @param {string} prefix
- * @returns {() => string}
- */
-function props_id_generator(prefix) {
-	let uid = 1;
-	return () => `${prefix}s${uid++}`;
-}
-
 /**
  * Only available on the server and when compiling with the `server` option.
  * Takes a component and returns an object with `body` and `head` properties on it, which you can use to populate the HTML when server-rendering your app.
@@ -106,14 +66,7 @@ function props_id_generator(prefix) {
  * @returns {RenderOutput}
  */
 export function render(component, options = {}) {
-	const uid = props_id_generator(options.idPrefix ? options.idPrefix + '-' : '');
-	/** @type {Payload} */
-	const payload = {
-		out: '',
-		css: new Set(),
-		head: { title: '', out: '', css: new Set(), uid },
-		uid
-	};
+	const payload = new Payload(options.idPrefix ? options.idPrefix + '-' : '');
 
 	const prev_on_destroy = on_destroy;
 	on_destroy = [];
@@ -545,7 +498,9 @@ export { html } from './blocks/html.js';
 
 export { push, pop } from './context.js';
 
-export { push_element, pop_element } from './dev.js';
+export { push_element, pop_element, validate_snippet_args } from './dev.js';
+
+export { assign_payload, copy_payload } from './payload.js';
 
 export { snapshot } from '../shared/clone.js';
 
diff --git a/packages/svelte/src/internal/server/payload.js b/packages/svelte/src/internal/server/payload.js
new file mode 100644
index 0000000000..03bcaf492e
--- /dev/null
+++ b/packages/svelte/src/internal/server/payload.js
@@ -0,0 +1,64 @@
+export class Payload {
+	/** @type {Set<{ hash: string; code: string }>} */
+	css = new Set();
+	out = '';
+	uid = () => '';
+
+	head = {
+		/** @type {Set<{ hash: string; code: string }>} */
+		css: new Set(),
+		title: '',
+		out: '',
+		uid: () => ''
+	};
+
+	constructor(id_prefix = '') {
+		this.uid = props_id_generator(id_prefix);
+		this.head.uid = this.uid;
+	}
+}
+
+/**
+ * Used in legacy mode to handle bindings
+ * @param {Payload} to_copy
+ * @returns {Payload}
+ */
+export function copy_payload({ out, css, head, uid }) {
+	const payload = new Payload();
+
+	payload.out = out;
+	payload.css = new Set(css);
+	payload.uid = uid;
+
+	payload.head = {
+		title: head.title,
+		out: head.out,
+		css: new Set(head.css),
+		uid: head.uid
+	};
+
+	return payload;
+}
+
+/**
+ * Assigns second payload to first
+ * @param {Payload} p1
+ * @param {Payload} p2
+ * @returns {void}
+ */
+export function assign_payload(p1, p2) {
+	p1.out = p2.out;
+	p1.css = p2.css;
+	p1.head = p2.head;
+	p1.uid = p2.uid;
+}
+
+/**
+ * Creates an ID generator
+ * @param {string} prefix
+ * @returns {() => string}
+ */
+function props_id_generator(prefix) {
+	let uid = 1;
+	return () => `${prefix}s${uid++}`;
+}
diff --git a/packages/svelte/src/internal/server/types.d.ts b/packages/svelte/src/internal/server/types.d.ts
index 2fffdbbdf0..6b0fc146c4 100644
--- a/packages/svelte/src/internal/server/types.d.ts
+++ b/packages/svelte/src/internal/server/types.d.ts
@@ -11,19 +11,6 @@ export interface Component {
 	function?: any;
 }
 
-export interface Payload {
-	out: string;
-	css: Set<{ hash: string; code: string }>;
-	head: {
-		title: string;
-		out: string;
-		uid: () => string;
-		css: Set<{ hash: string; code: string }>;
-	};
-	/** Function that generates a unique ID */
-	uid: () => string;
-}
-
 export interface RenderOutput {
 	/** HTML that goes into the `<head>` */
 	head: string;
diff --git a/packages/svelte/src/internal/shared/errors.js b/packages/svelte/src/internal/shared/errors.js
index 26d6822cdb..2e89dc1ad1 100644
--- a/packages/svelte/src/internal/shared/errors.js
+++ b/packages/svelte/src/internal/shared/errors.js
@@ -17,6 +17,21 @@ export function invalid_default_snippet() {
 	}
 }
 
+/**
+ * A snippet function was passed invalid arguments. Snippets should only be instantiated via `{@render ...}`
+ * @returns {never}
+ */
+export function invalid_snippet_arguments() {
+	if (DEV) {
+		const error = new Error(`invalid_snippet_arguments\nA snippet function was passed invalid arguments. Snippets should only be instantiated via \`{@render ...}\`\nhttps://svelte.dev/e/invalid_snippet_arguments`);
+
+		error.name = 'Svelte error';
+		throw error;
+	} else {
+		throw new Error(`https://svelte.dev/e/invalid_snippet_arguments`);
+	}
+}
+
 /**
  * `%name%(...)` can only be used during component initialisation
  * @param {string} name

From 01171096cef8652704b92053e57156ae4ed9e5d9 Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Fri, 11 Apr 2025 04:42:44 +0200
Subject: [PATCH 09/27] feat: add `css.hasGlobal` to `compile` output (#15450)

* feat: add `hasUnscopedGlobalCss` to `compile` metadata

* chore: rename to `has_unscoped_global`

* fix: handle `-global` keyframes

* chore: guard the check if the value is already true

* update types

* add tests

* tweak

* tweak

* regenerate types

* Update .changeset/plenty-hotels-mix.md

* fix test, add failing test

* fix

* fix

* fix jsdoc

* unused

* fix

* lint

* rename

* rename

* reduce indirection

* tidy up

* revert

* tweak

* lint

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/plenty-hotels-mix.md               |  5 ++
 .../src/compiler/phases/1-parse/read/style.js |  2 +
 .../phases/2-analyze/css/css-analyze.js       | 70 ++++++++++++++-----
 .../src/compiler/phases/2-analyze/index.js    |  3 +-
 .../compiler/phases/3-transform/css/index.js  |  3 +-
 .../svelte/src/compiler/phases/types.d.ts     |  1 +
 packages/svelte/src/compiler/types/css.d.ts   |  5 ++
 packages/svelte/src/compiler/types/index.d.ts |  2 +
 .../css/samples/global-keyframes/_config.js   |  5 ++
 .../samples/global-local-nested/_config.js    |  5 ++
 .../samples/global-local-nested/expected.css  | 12 ++++
 .../samples/global-local-nested/input.svelte  | 15 ++++
 .../tests/css/samples/global-local/_config.js |  5 ++
 .../css/samples/global-local/expected.css     |  8 +++
 .../css/samples/global-local/input.svelte     | 11 +++
 .../samples/global-with-nesting/_config.js    |  4 +-
 .../tests/css/samples/global/_config.js       |  5 ++
 packages/svelte/tests/css/test.ts             |  9 +++
 packages/svelte/tests/helpers.js              |  4 ++
 packages/svelte/types/index.d.ts              |  2 +
 20 files changed, 155 insertions(+), 21 deletions(-)
 create mode 100644 .changeset/plenty-hotels-mix.md
 create mode 100644 packages/svelte/tests/css/samples/global-keyframes/_config.js
 create mode 100644 packages/svelte/tests/css/samples/global-local-nested/_config.js
 create mode 100644 packages/svelte/tests/css/samples/global-local-nested/expected.css
 create mode 100644 packages/svelte/tests/css/samples/global-local-nested/input.svelte
 create mode 100644 packages/svelte/tests/css/samples/global-local/_config.js
 create mode 100644 packages/svelte/tests/css/samples/global-local/expected.css
 create mode 100644 packages/svelte/tests/css/samples/global-local/input.svelte
 create mode 100644 packages/svelte/tests/css/samples/global/_config.js

diff --git a/.changeset/plenty-hotels-mix.md b/.changeset/plenty-hotels-mix.md
new file mode 100644
index 0000000000..5e7aa834da
--- /dev/null
+++ b/.changeset/plenty-hotels-mix.md
@@ -0,0 +1,5 @@
+---
+'svelte': minor
+---
+
+feat: add `css.hasGlobal` to `compile` output
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 f8c39f1b1d..56dbe124b7 100644
--- a/packages/svelte/src/compiler/phases/1-parse/read/style.js
+++ b/packages/svelte/src/compiler/phases/1-parse/read/style.js
@@ -118,6 +118,7 @@ function read_rule(parser) {
 		metadata: {
 			parent_rule: null,
 			has_local_selectors: false,
+			has_global_selectors: false,
 			is_global_block: false
 		}
 	};
@@ -342,6 +343,7 @@ function read_selector(parser, inside_pseudo_class = false) {
 				children,
 				metadata: {
 					rule: null,
+					is_global: false,
 					used: false
 				}
 			};
diff --git a/packages/svelte/src/compiler/phases/2-analyze/css/css-analyze.js b/packages/svelte/src/compiler/phases/2-analyze/css/css-analyze.js
index 362ac9dcad..76cb2f56e9 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/css/css-analyze.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/css/css-analyze.js
@@ -7,13 +7,15 @@ import { is_keyframes_node } from '../../css.js';
 import { is_global, is_unscoped_pseudo_class } from './utils.js';
 
 /**
- * @typedef {Visitors<
- *   AST.CSS.Node,
- *   {
- *     keyframes: string[];
- *     rule: AST.CSS.Rule | null;
- *   }
- * >} CssVisitors
+ * @typedef {{
+ *   keyframes: string[];
+ *   rule: AST.CSS.Rule | null;
+ *   analysis: ComponentAnalysis;
+ * }} CssState
+ */
+
+/**
+ * @typedef {Visitors<AST.CSS.Node, CssState>} CssVisitors
  */
 
 /**
@@ -28,6 +30,15 @@ function is_global_block_selector(simple_selector) {
 	);
 }
 
+/**
+ * @param {AST.SvelteNode[]} path
+ */
+function is_unscoped(path) {
+	return path
+		.filter((node) => node.type === 'Rule')
+		.every((node) => node.metadata.has_global_selectors);
+}
+
 /**
  *
  * @param {Array<AST.CSS.Node>} path
@@ -42,6 +53,9 @@ const css_visitors = {
 		if (is_keyframes_node(node)) {
 			if (!node.prelude.startsWith('-global-') && !is_in_global_block(context.path)) {
 				context.state.keyframes.push(node.prelude);
+			} else if (node.prelude.startsWith('-global-')) {
+				// we don't check if the block.children.length because the keyframe is still added even if empty
+				context.state.analysis.css.has_global ||= is_unscoped(context.path);
 			}
 		}
 
@@ -99,10 +113,12 @@ const css_visitors = {
 
 		node.metadata.rule = context.state.rule;
 
-		node.metadata.used ||= node.children.every(
+		node.metadata.is_global = node.children.every(
 			({ metadata }) => metadata.is_global || metadata.is_global_like
 		);
 
+		node.metadata.used ||= node.metadata.is_global;
+
 		if (
 			node.metadata.rule?.metadata.parent_rule &&
 			node.children[0]?.selectors[0]?.type === 'NestingSelector'
@@ -190,6 +206,7 @@ const css_visitors = {
 
 				if (idx !== -1) {
 					is_global_block = true;
+
 					for (let i = idx + 1; i < child.selectors.length; i++) {
 						walk(/** @type {AST.CSS.Node} */ (child.selectors[i]), null, {
 							ComplexSelector(node) {
@@ -242,16 +259,26 @@ const css_visitors = {
 			}
 		}
 
-		context.next({
-			...context.state,
-			rule: node
-		});
+		const state = { ...context.state, rule: node };
 
-		node.metadata.has_local_selectors = node.prelude.children.some((selector) => {
-			return selector.children.some(
-				({ metadata }) => !metadata.is_global && !metadata.is_global_like
-			);
-		});
+		// visit selector list first, to populate child selector metadata
+		context.visit(node.prelude, state);
+
+		for (const selector of node.prelude.children) {
+			node.metadata.has_global_selectors ||= selector.metadata.is_global;
+			node.metadata.has_local_selectors ||= !selector.metadata.is_global;
+		}
+
+		// if this rule has a ComplexSelector whose RelativeSelector children are all
+		// `:global(...)`, and the rule contains declarations (rather than just
+		// nested rules) then the component as a whole includes global CSS
+		context.state.analysis.css.has_global ||=
+			node.metadata.has_global_selectors &&
+			node.block.children.filter((child) => child.type === 'Declaration').length > 0 &&
+			is_unscoped(context.path);
+
+		// visit block list, so parent rule metadata is populated
+		context.visit(node.block, state);
 	},
 	NestingSelector(node, context) {
 		const rule = /** @type {AST.CSS.Rule} */ (context.state.rule);
@@ -289,5 +316,12 @@ const css_visitors = {
  * @param {ComponentAnalysis} analysis
  */
 export function analyze_css(stylesheet, analysis) {
-	walk(stylesheet, { keyframes: analysis.css.keyframes, rule: null }, css_visitors);
+	/** @type {CssState} */
+	const css_state = {
+		keyframes: analysis.css.keyframes,
+		rule: null,
+		analysis
+	};
+
+	walk(stylesheet, css_state, css_visitors);
 }
diff --git a/packages/svelte/src/compiler/phases/2-analyze/index.js b/packages/svelte/src/compiler/phases/2-analyze/index.js
index c62fb03e8f..a6eb9565cb 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/index.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/index.js
@@ -456,7 +456,8 @@ export function analyze_component(root, source, options) {
 						hash
 					})
 				: '',
-			keyframes: []
+			keyframes: [],
+			has_global: false
 		},
 		source,
 		undefined_exports: new Map(),
diff --git a/packages/svelte/src/compiler/phases/3-transform/css/index.js b/packages/svelte/src/compiler/phases/3-transform/css/index.js
index 5b0dcd5588..dff034f8aa 100644
--- a/packages/svelte/src/compiler/phases/3-transform/css/index.js
+++ b/packages/svelte/src/compiler/phases/3-transform/css/index.js
@@ -59,7 +59,8 @@ export function render_stylesheet(source, analysis, options) {
 			// generateMap takes care of calculating source relative to file
 			source: options.filename,
 			file: options.cssOutputFilename || options.filename
-		})
+		}),
+		hasGlobal: analysis.css.has_global
 	};
 
 	merge_with_preprocessor_map(css, options, css.map.sources[0]);
diff --git a/packages/svelte/src/compiler/phases/types.d.ts b/packages/svelte/src/compiler/phases/types.d.ts
index f09b881303..f98cbe1415 100644
--- a/packages/svelte/src/compiler/phases/types.d.ts
+++ b/packages/svelte/src/compiler/phases/types.d.ts
@@ -74,6 +74,7 @@ export interface ComponentAnalysis extends Analysis {
 		ast: AST.CSS.StyleSheet | null;
 		hash: string;
 		keyframes: string[];
+		has_global: boolean;
 	};
 	source: string;
 	undefined_exports: Map<string, Node>;
diff --git a/packages/svelte/src/compiler/types/css.d.ts b/packages/svelte/src/compiler/types/css.d.ts
index 7b2e6ae5f7..154a06ffb1 100644
--- a/packages/svelte/src/compiler/types/css.d.ts
+++ b/packages/svelte/src/compiler/types/css.d.ts
@@ -34,6 +34,10 @@ export namespace _CSS {
 		metadata: {
 			parent_rule: null | Rule;
 			has_local_selectors: boolean;
+			/**
+			 * `true` if the rule contains a ComplexSelector whose RelativeSelectors are all global or global-like
+			 */
+			has_global_selectors: boolean;
 			/**
 			 * `true` if the rule contains a `:global` selector, and therefore everything inside should be unscoped
 			 */
@@ -64,6 +68,7 @@ export namespace _CSS {
 		/** @internal */
 		metadata: {
 			rule: null | Rule;
+			is_global: boolean;
 			/** True if this selector applies to an element. For global selectors, this is defined in css-analyze, for others in css-prune while scoping */
 			used: boolean;
 		};
diff --git a/packages/svelte/src/compiler/types/index.d.ts b/packages/svelte/src/compiler/types/index.d.ts
index eec41bad9d..616c346ad3 100644
--- a/packages/svelte/src/compiler/types/index.d.ts
+++ b/packages/svelte/src/compiler/types/index.d.ts
@@ -18,6 +18,8 @@ export interface CompileResult {
 		code: string;
 		/** A source map */
 		map: SourceMap;
+		/** Whether or not the CSS includes global rules */
+		hasGlobal: boolean;
 	};
 	/**
 	 * An array of warning objects that were generated during compilation. Each warning has several properties:
diff --git a/packages/svelte/tests/css/samples/global-keyframes/_config.js b/packages/svelte/tests/css/samples/global-keyframes/_config.js
new file mode 100644
index 0000000000..30953854ad
--- /dev/null
+++ b/packages/svelte/tests/css/samples/global-keyframes/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	hasGlobal: true
+});
diff --git a/packages/svelte/tests/css/samples/global-local-nested/_config.js b/packages/svelte/tests/css/samples/global-local-nested/_config.js
new file mode 100644
index 0000000000..5a7796ebac
--- /dev/null
+++ b/packages/svelte/tests/css/samples/global-local-nested/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	hasGlobal: false
+});
diff --git a/packages/svelte/tests/css/samples/global-local-nested/expected.css b/packages/svelte/tests/css/samples/global-local-nested/expected.css
new file mode 100644
index 0000000000..8eadf2b948
--- /dev/null
+++ b/packages/svelte/tests/css/samples/global-local-nested/expected.css
@@ -0,0 +1,12 @@
+
+	div.svelte-xyz {
+		.whatever {
+			color: green;
+		}
+	}
+
+	.whatever {
+		div.svelte-xyz {
+			color: green;
+		}
+	}
diff --git a/packages/svelte/tests/css/samples/global-local-nested/input.svelte b/packages/svelte/tests/css/samples/global-local-nested/input.svelte
new file mode 100644
index 0000000000..60210be753
--- /dev/null
+++ b/packages/svelte/tests/css/samples/global-local-nested/input.svelte
@@ -0,0 +1,15 @@
+<div>{@html whatever}</div>
+
+<style>
+	div {
+		:global(.whatever) {
+			color: green;
+		}
+	}
+
+	:global(.whatever) {
+		div {
+			color: green;
+		}
+	}
+</style>
diff --git a/packages/svelte/tests/css/samples/global-local/_config.js b/packages/svelte/tests/css/samples/global-local/_config.js
new file mode 100644
index 0000000000..5a7796ebac
--- /dev/null
+++ b/packages/svelte/tests/css/samples/global-local/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	hasGlobal: false
+});
diff --git a/packages/svelte/tests/css/samples/global-local/expected.css b/packages/svelte/tests/css/samples/global-local/expected.css
new file mode 100644
index 0000000000..c4fc74fb1a
--- /dev/null
+++ b/packages/svelte/tests/css/samples/global-local/expected.css
@@ -0,0 +1,8 @@
+
+	div.svelte-xyz .whatever {
+		color: green;
+	}
+
+	.whatever div.svelte-xyz {
+		color: green;
+	}
diff --git a/packages/svelte/tests/css/samples/global-local/input.svelte b/packages/svelte/tests/css/samples/global-local/input.svelte
new file mode 100644
index 0000000000..bff97ab485
--- /dev/null
+++ b/packages/svelte/tests/css/samples/global-local/input.svelte
@@ -0,0 +1,11 @@
+<div>{@html whatever}</div>
+
+<style>
+	div :global(.whatever) {
+		color: green;
+	}
+
+	:global(.whatever) div {
+		color: green;
+	}
+</style>
diff --git a/packages/svelte/tests/css/samples/global-with-nesting/_config.js b/packages/svelte/tests/css/samples/global-with-nesting/_config.js
index 292c6c49ac..6cec7c2360 100644
--- a/packages/svelte/tests/css/samples/global-with-nesting/_config.js
+++ b/packages/svelte/tests/css/samples/global-with-nesting/_config.js
@@ -1,5 +1,7 @@
 import { test } from '../../test';
 
 export default test({
-	warnings: []
+	warnings: [],
+
+	hasGlobal: false
 });
diff --git a/packages/svelte/tests/css/samples/global/_config.js b/packages/svelte/tests/css/samples/global/_config.js
new file mode 100644
index 0000000000..30953854ad
--- /dev/null
+++ b/packages/svelte/tests/css/samples/global/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	hasGlobal: true
+});
diff --git a/packages/svelte/tests/css/test.ts b/packages/svelte/tests/css/test.ts
index dd51f52eab..8846b1d986 100644
--- a/packages/svelte/tests/css/test.ts
+++ b/packages/svelte/tests/css/test.ts
@@ -34,6 +34,7 @@ interface CssTest extends BaseTest {
 	compileOptions?: Partial<CompileOptions>;
 	warnings?: Warning[];
 	props?: Record<string, any>;
+	hasGlobal?: boolean;
 }
 
 /**
@@ -78,6 +79,14 @@ const { test, run } = suite<CssTest>(async (config, cwd) => {
 		// assert_html_equal(actual_ssr, expected.html);
 	}
 
+	if (config.hasGlobal !== undefined) {
+		const metadata = JSON.parse(
+			fs.readFileSync(`${cwd}/_output/client/input.svelte.css.json`, 'utf-8')
+		);
+
+		assert.equal(metadata.hasGlobal, config.hasGlobal);
+	}
+
 	const dom_css = fs.readFileSync(`${cwd}/_output/client/input.svelte.css`, 'utf-8').trim();
 	const ssr_css = fs.readFileSync(`${cwd}/_output/server/input.svelte.css`, 'utf-8').trim();
 
diff --git a/packages/svelte/tests/helpers.js b/packages/svelte/tests/helpers.js
index 87bcb473e7..f853d5873c 100644
--- a/packages/svelte/tests/helpers.js
+++ b/packages/svelte/tests/helpers.js
@@ -146,6 +146,10 @@ export async function compile_directory(
 
 			if (compiled.css) {
 				write(`${output_dir}/${file}.css`, compiled.css.code);
+				write(
+					`${output_dir}/${file}.css.json`,
+					JSON.stringify({ hasGlobal: compiled.css.hasGlobal })
+				);
 				if (output_map) {
 					write(`${output_dir}/${file}.css.map`, JSON.stringify(compiled.css.map, null, '\t'));
 				}
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index c6000fc4b6..6f12daf187 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -753,6 +753,8 @@ declare module 'svelte/compiler' {
 			code: string;
 			/** A source map */
 			map: SourceMap;
+			/** Whether or not the CSS includes global rules */
+			hasGlobal: boolean;
 		};
 		/**
 		 * An array of warning objects that were generated during compilation. Each warning has several properties:

From 02448a9acdf781ea44b696d4a60f387b8856e82c Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Thu, 10 Apr 2025 23:19:23 -0400
Subject: [PATCH 10/27] Version Packages (#15731)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/bright-jeans-compare.md |  5 -----
 .changeset/plenty-hotels-mix.md    |  5 -----
 packages/svelte/CHANGELOG.md       | 10 ++++++++++
 packages/svelte/package.json       |  2 +-
 packages/svelte/src/version.js     |  2 +-
 5 files changed, 12 insertions(+), 12 deletions(-)
 delete mode 100644 .changeset/bright-jeans-compare.md
 delete mode 100644 .changeset/plenty-hotels-mix.md

diff --git a/.changeset/bright-jeans-compare.md b/.changeset/bright-jeans-compare.md
deleted file mode 100644
index eaec658e03..0000000000
--- a/.changeset/bright-jeans-compare.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: add snippet argument validation in dev
diff --git a/.changeset/plenty-hotels-mix.md b/.changeset/plenty-hotels-mix.md
deleted file mode 100644
index 5e7aa834da..0000000000
--- a/.changeset/plenty-hotels-mix.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': minor
----
-
-feat: add `css.hasGlobal` to `compile` output
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index f27a6640bd..68a8803663 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,15 @@
 # svelte
 
+## 5.26.0
+
+### Minor Changes
+
+- feat: add `css.hasGlobal` to `compile` output ([#15450](https://github.com/sveltejs/svelte/pull/15450))
+
+### Patch Changes
+
+- fix: add snippet argument validation in dev ([#15521](https://github.com/sveltejs/svelte/pull/15521))
+
 ## 5.25.12
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 67f6186fc7..8267cb5218 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": "5.25.12",
+  "version": "5.26.0",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index c554e9018c..ade51aaf17 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 = '5.25.12';
+export const VERSION = '5.26.0';
 export const PUBLIC_VERSION = '5';

From 95a020acead1a403ae2d4320bea57227e52143ec Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 11 Apr 2025 10:01:51 -0400
Subject: [PATCH 11/27] fix: update `state_referenced_locally` message (#15733)

* fix: update state_referenced_locally message

* changeset

* update message
---
 .changeset/stale-gorillas-judge.md            |  5 ++++
 .../.generated/compile-warnings.md            |  9 +++---
 .../messages/compile-warnings/script.md       |  9 +++---
 .../phases/2-analyze/visitors/Identifier.js   | 30 ++++++++++++++++++-
 packages/svelte/src/compiler/warnings.js      |  8 +++--
 .../static-state-reference/input.svelte       |  1 +
 .../static-state-reference/warnings.json      | 24 +++++++++++----
 7 files changed, 68 insertions(+), 18 deletions(-)
 create mode 100644 .changeset/stale-gorillas-judge.md

diff --git a/.changeset/stale-gorillas-judge.md b/.changeset/stale-gorillas-judge.md
new file mode 100644
index 0000000000..3d91f401dd
--- /dev/null
+++ b/.changeset/stale-gorillas-judge.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: update `state_referenced_locally` message
diff --git a/documentation/docs/98-reference/.generated/compile-warnings.md b/documentation/docs/98-reference/.generated/compile-warnings.md
index 57396bd7fd..0e94cbadb2 100644
--- a/documentation/docs/98-reference/.generated/compile-warnings.md
+++ b/documentation/docs/98-reference/.generated/compile-warnings.md
@@ -823,15 +823,16 @@ See [the migration guide](v5-migration-guide#Snippets-instead-of-slots) for more
 ### state_referenced_locally
 
 ```
-State referenced in its own scope will never update. Did you mean to reference it inside a closure?
+This reference only captures the initial value of `%name%`. Did you mean to reference it inside a %type% instead?
 ```
 
 This warning is thrown when the compiler detects the following:
+
 - A reactive variable is declared
-- the variable is reassigned
-- the variable is referenced inside the same scope it is declared and it is a non-reactive context
+- ...and later reassigned...
+- ...and referenced in the same scope
 
-In this case, the state reassignment will not be noticed by whatever you passed it to. For example, if you pass the state to a function, that function will not notice the updates:
+This 'breaks the link' to the original state declaration. For example, if you pass the state to a function, the function loses access to the state once it is reassigned:
 
 ```svelte
 <!--- file: Parent.svelte --->
diff --git a/packages/svelte/messages/compile-warnings/script.md b/packages/svelte/messages/compile-warnings/script.md
index 8c32fb7082..6603759156 100644
--- a/packages/svelte/messages/compile-warnings/script.md
+++ b/packages/svelte/messages/compile-warnings/script.md
@@ -54,14 +54,15 @@ To fix this, wrap your variable declaration with `$state`.
 
 ## state_referenced_locally
 
-> State referenced in its own scope will never update. Did you mean to reference it inside a closure?
+> This reference only captures the initial value of `%name%`. Did you mean to reference it inside a %type% instead?
 
 This warning is thrown when the compiler detects the following:
+
 - A reactive variable is declared
-- the variable is reassigned
-- the variable is referenced inside the same scope it is declared and it is a non-reactive context
+- ...and later reassigned...
+- ...and referenced in the same scope
 
-In this case, the state reassignment will not be noticed by whatever you passed it to. For example, if you pass the state to a function, that function will not notice the updates:
+This 'breaks the link' to the original state declaration. For example, if you pass the state to a function, the function loses access to the state once it is reassigned:
 
 ```svelte
 <!--- file: Parent.svelte --->
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/Identifier.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/Identifier.js
index 79dccd5a7c..dcbe564543 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/Identifier.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/Identifier.js
@@ -7,6 +7,7 @@ import * as e from '../../../errors.js';
 import * as w from '../../../warnings.js';
 import { is_rune } from '../../../../utils.js';
 import { mark_subtree_dynamic } from './shared/fragment.js';
+import { get_rune } from '../../scope.js';
 
 /**
  * @param {Identifier} node
@@ -111,7 +112,34 @@ export function Identifier(node, context) {
 			(parent.type !== 'AssignmentExpression' || parent.left !== node) &&
 			parent.type !== 'UpdateExpression'
 		) {
-			w.state_referenced_locally(node);
+			let type = 'closure';
+
+			let i = context.path.length;
+			while (i--) {
+				const parent = context.path[i];
+
+				if (
+					parent.type === 'ArrowFunctionExpression' ||
+					parent.type === 'FunctionDeclaration' ||
+					parent.type === 'FunctionExpression'
+				) {
+					break;
+				}
+
+				if (
+					parent.type === 'CallExpression' &&
+					parent.arguments.includes(/** @type {any} */ (context.path[i + 1]))
+				) {
+					const rune = get_rune(parent, context.state.scope);
+
+					if (rune === '$state' || rune === '$state.raw') {
+						type = 'derived';
+						break;
+					}
+				}
+			}
+
+			w.state_referenced_locally(node, node.name, type);
 		}
 
 		if (
diff --git a/packages/svelte/src/compiler/warnings.js b/packages/svelte/src/compiler/warnings.js
index a9ea617d3f..e6fc8caba5 100644
--- a/packages/svelte/src/compiler/warnings.js
+++ b/packages/svelte/src/compiler/warnings.js
@@ -641,11 +641,13 @@ export function reactive_declaration_module_script_dependency(node) {
 }
 
 /**
- * State referenced in its own scope will never update. Did you mean to reference it inside a closure?
+ * This reference only captures the initial value of `%name%`. Did you mean to reference it inside a %type% instead?
  * @param {null | NodeLike} node
+ * @param {string} name
+ * @param {string} type
  */
-export function state_referenced_locally(node) {
-	w(node, 'state_referenced_locally', `State referenced in its own scope will never update. Did you mean to reference it inside a closure?\nhttps://svelte.dev/e/state_referenced_locally`);
+export function state_referenced_locally(node, name, type) {
+	w(node, 'state_referenced_locally', `This reference only captures the initial value of \`${name}\`. Did you mean to reference it inside a ${type} instead?\nhttps://svelte.dev/e/state_referenced_locally`);
 }
 
 /**
diff --git a/packages/svelte/tests/validator/samples/static-state-reference/input.svelte b/packages/svelte/tests/validator/samples/static-state-reference/input.svelte
index cd0c7b7349..577527ee60 100644
--- a/packages/svelte/tests/validator/samples/static-state-reference/input.svelte
+++ b/packages/svelte/tests/validator/samples/static-state-reference/input.svelte
@@ -2,6 +2,7 @@
 	let obj = $state({ a: 0 });
 	let count = $state(0);
 	let doubled = $derived(count * 2);
+	let tripled = $state(count * 3);
 
 	console.log(obj);
 	console.log(count);
diff --git a/packages/svelte/tests/validator/samples/static-state-reference/warnings.json b/packages/svelte/tests/validator/samples/static-state-reference/warnings.json
index 9ba0941519..a118d5e4a0 100644
--- a/packages/svelte/tests/validator/samples/static-state-reference/warnings.json
+++ b/packages/svelte/tests/validator/samples/static-state-reference/warnings.json
@@ -1,26 +1,38 @@
 [
 	{
 		"code": "state_referenced_locally",
-		"message": "State referenced in its own scope will never update. Did you mean to reference it inside a closure?",
+		"message": "This reference only captures the initial value of `count`. Did you mean to reference it inside a derived instead?",
+		"start": {
+			"column": 22,
+			"line": 5
+		},
+		"end": {
+			"column": 27,
+			"line": 5
+		}
+	},
+	{
+		"code": "state_referenced_locally",
+		"message": "This reference only captures the initial value of `count`. Did you mean to reference it inside a closure instead?",
 		"start": {
 			"column": 13,
-			"line": 7
+			"line": 8
 		},
 		"end": {
 			"column": 18,
-			"line": 7
+			"line": 8
 		}
 	},
 	{
 		"code": "state_referenced_locally",
-		"message": "State referenced in its own scope will never update. Did you mean to reference it inside a closure?",
+		"message": "This reference only captures the initial value of `doubled`. Did you mean to reference it inside a closure instead?",
 		"start": {
 			"column": 13,
-			"line": 8
+			"line": 9
 		},
 		"end": {
 			"column": 20,
-			"line": 8
+			"line": 9
 		}
 	}
 ]

From 9b2507131ca0134b59cef7da1fdd59603c519f0a Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 11 Apr 2025 10:50:11 -0400
Subject: [PATCH 12/27] chore: remove unused documentation markdown files
 (#15738)

---
 .../docs/01-introduction/xx-props.md          | 139 -----------------
 .../xx-reactivity-fundamentals.md             | 144 ------------------
 .../03-template-syntax/xx-control-flow.md     | 111 --------------
 .../03-template-syntax/xx-data-fetching.md    |  20 ---
 .../docs/07-misc/xx-reactivity-indepth.md     |   6 -
 5 files changed, 420 deletions(-)
 delete mode 100644 documentation/docs/01-introduction/xx-props.md
 delete mode 100644 documentation/docs/01-introduction/xx-reactivity-fundamentals.md
 delete mode 100644 documentation/docs/03-template-syntax/xx-control-flow.md
 delete mode 100644 documentation/docs/03-template-syntax/xx-data-fetching.md
 delete mode 100644 documentation/docs/07-misc/xx-reactivity-indepth.md

diff --git a/documentation/docs/01-introduction/xx-props.md b/documentation/docs/01-introduction/xx-props.md
deleted file mode 100644
index cad854d878..0000000000
--- a/documentation/docs/01-introduction/xx-props.md
+++ /dev/null
@@ -1,139 +0,0 @@
----
-title: Public API of a component
----
-
-### Public API of a component
-
-Svelte uses the `$props` rune to declare _properties_ or _props_, which means describing the public interface of the component which becomes accessible to consumers of the component.
-
-> [!NOTE] `$props` is one of several runes, which are special hints for Svelte's compiler to make things reactive.
-
-```svelte
-<script>
-	let { foo, bar, baz } = $props();
-
-	// Values that are passed in as props
-	// are immediately available
-	console.log({ foo, bar, baz });
-</script>
-```
-
-You can specify a fallback value for a prop. It will be used if the component's consumer doesn't specify the prop on the component when instantiating the component, or if the passed value is `undefined` at some point.
-
-```svelte
-<script>
-	let { foo = 'optional default initial value' } = $props();
-</script>
-```
-
-To get all properties, use rest syntax:
-
-```svelte
-<script>
-	let { a, b, c, ...everythingElse } = $props();
-</script>
-```
-
-You can use reserved words as prop names.
-
-```svelte
-<script>
-	// creates a `class` property, even
-	// though it is a reserved word
-	let { class: className } = $props();
-</script>
-```
-
-If you're using TypeScript, you can declare the prop types:
-
-```svelte
-<script lang="ts">
-	interface Props {
-		required: string;
-		optional?: number;
-		[key: string]: unknown;
-	}
-
-	let { required, optional, ...everythingElse }: Props = $props();
-</script>
-```
-
-If you're using JavaScript, you can declare the prop types using JSDoc:
-
-```svelte
-<script>
-	/** @type {{ x: string }} */
-	let { x } = $props();
-
-	// or use @typedef if you want to document the properties:
-
-	/**
-	 * @typedef {Object} MyProps
-	 * @property {string} y Some documentation
-	 */
-
-	/** @type {MyProps} */
-	let { y } = $props();
-</script>
-```
-
-If you export a `const`, `class` or `function`, it is readonly from outside the component.
-
-```svelte
-<script>
-	export const thisIs = 'readonly';
-
-	export function greet(name) {
-		alert(`hello ${name}!`);
-	}
-</script>
-```
-
-Readonly props can be accessed as properties on the element, tied to the component using [`bind:this` syntax](bindings#bind:this).
-
-### Reactive variables
-
-To change component state and trigger a re-render, just assign to a locally declared variable that was declared using the `$state` rune.
-
-Update expressions (`count += 1`) and property assignments (`obj.x = y`) have the same effect.
-
-```svelte
-<script>
-	let count = $state(0);
-
-	function handleClick() {
-		// calling this function will trigger an
-		// update if the markup references `count`
-		count = count + 1;
-	}
-</script>
-```
-
-Svelte's `<script>` blocks are run only when the component is created, so assignments within a `<script>` block are not automatically run again when a prop updates.
-
-```svelte
-<script>
-	let { person } = $props();
-	// this will only set `name` on component creation
-	// it will not update when `person` does
-	let { name } = person;
-</script>
-```
-
-If you'd like to react to changes to a prop, use the `$derived` or `$effect` runes instead.
-
-```svelte
-<script>
-	let count = $state(0);
-
-	let double = $derived(count * 2);
-
-	$effect(() => {
-		if (count > 10) {
-			alert('Too high!');
-		}
-	});
-</script>
-```
-
-For more information on reactivity, read the documentation around runes.
diff --git a/documentation/docs/01-introduction/xx-reactivity-fundamentals.md b/documentation/docs/01-introduction/xx-reactivity-fundamentals.md
deleted file mode 100644
index d5e67ada71..0000000000
--- a/documentation/docs/01-introduction/xx-reactivity-fundamentals.md
+++ /dev/null
@@ -1,144 +0,0 @@
----
-title: Reactivity fundamentals
----
-
-Reactivity is at the heart of interactive UIs. When you click a button, you expect some kind of response. It's your job as a developer to make this happen. It's Svelte's job to make your job as intuitive as possible, by providing a good API to express reactive systems.
-
-## Runes
-
-Svelte 5 uses _runes_, a powerful set of primitives for controlling reactivity inside your Svelte components and inside `.svelte.js` and `.svelte.ts` modules.
-
-Runes are function-like symbols that provide instructions to the Svelte compiler. You don't need to import them from anywhere — when you use Svelte, they're part of the language.
-
-The following sections introduce the most important runes for declare state, derived state and side effects at a high level. For more details refer to the later sections on [state](state) and [side effects](side-effects).
-
-## `$state`
-
-Reactive state is declared with the `$state` rune:
-
-```svelte
-<script>
-	let count = $state(0);
-</script>
-
-<button onclick={() => count++}>
-	clicks: {count}
-</button>
-```
-
-You can also use `$state` in class fields (whether public or private):
-
-```js
-// @errors: 7006 2554
-class Todo {
-	done = $state(false);
-	text = $state();
-
-	constructor(text) {
-		this.text = text;
-	}
-}
-```
-
-> [!LEGACY]
-> In Svelte 4, state was implicitly reactive if the variable was declared at the top level
->
-> ```svelte
-> <script>
-> 	let count = 0;
-> </script>
->
-> <button on:click={() => count++}>
-> 	clicks: {count}
-> </button>
-> ```
-
-## `$derived`
-
-Derived state is declared with the `$derived` rune:
-
-```svelte
-<script>
-	let count = $state(0);
-	let doubled = $derived(count * 2);
-</script>
-
-<button onclick={() => count++}>
-	{doubled}
-</button>
-
-<p>{count} doubled is {doubled}</p>
-```
-
-The expression inside `$derived(...)` should be free of side-effects. Svelte will disallow state changes (e.g. `count++`) inside derived expressions.
-
-As with `$state`, you can mark class fields as `$derived`.
-
-> [!LEGACY]
-> In Svelte 4, you could use reactive statements for this.
->
-> ```svelte
-> <script>
-> 	let count = 0;
-> 	$: doubled = count * 2;
-> </script>
->
-> <button on:click={() => count++}>
-> 	{doubled}
-> </button>
->
-> <p>{count} doubled is {doubled}</p>
-> ```
->
-> This only worked at the top level of a component.
-
-## `$effect`
-
-To run _side-effects_ when the component is mounted to the DOM, and when values change, we can use the `$effect` rune ([demo](/playground/untitled#H4sIAAAAAAAAE31T24rbMBD9lUG7kAQ2sbdlX7xOYNk_aB_rQhRpbAsU2UiTW0P-vbrYubSlYGzmzMzROTPymdVKo2PFjzMzfIusYB99z14YnfoQuD1qQh-7bmdFQEonrOppVZmKNBI49QthCc-OOOH0LZ-9jxnR6c7eUpOnuv6KeT5JFdcqbvbcBcgDz1jXKGg6ncFyBedYR6IzLrAZwiN5vtSxaJA-EzadfJEjKw11C6GR22-BLH8B_wxdByWpvUYtqqal2XB6RVkG1CoHB6U1WJzbnYFDiwb3aGEdDa3Bm1oH12sQLTcNPp7r56m_00mHocSG97_zd7ICUXonA5fwKbPbkE2ZtMJGGVkEdctzQi4QzSwr9prnFYNk5hpmqVuqPQjNnfOJoMF22lUsrq_UfIN6lfSVyvQ7grB3X2mjMZYO3XO9w-U5iLx42qg29md3BP_ni5P4gy9ikTBlHxjLzAtPDlyYZmRdjAbGq7HprEQ7p64v4LU_guu0kvAkhBim3nMplWl8FreQD-CW20aZR0wq12t-KqDWeBywhvexKC3memmDwlHAv9q4Vo2ZK8KtK0CgX7u9J8wXbzdKv-nRnfF_2baTqlYoWUF2h5efl9-n0O6koAMAAA==)):
-
-```svelte
-<script>
-	let size = $state(50);
-	let color = $state('#ff3e00');
-
-	let canvas;
-
-	$effect(() => {
-		const context = canvas.getContext('2d');
-		context.clearRect(0, 0, canvas.width, canvas.height);
-
-		// this will re-run whenever `color` or `size` change
-		context.fillStyle = color;
-		context.fillRect(0, 0, size, size);
-	});
-</script>
-
-<canvas bind:this={canvas} width="100" height="100" />
-```
-
-The function passed to `$effect` will run when the component mounts, and will re-run after any changes to the values it reads that were declared with `$state` or `$derived` (including those passed in with `$props`). Re-runs are batched (i.e. changing `color` and `size` in the same moment won't cause two separate runs), and happen after any DOM updates have been applied.
-
-> [!LEGACY]
-> In Svelte 4, you could use reactive statements for this.
->
-> ```svelte
-> <script>
-> 	let size = 50;
-> 	let color = '#ff3e00';
->
-> 	let canvas;
->
-> 	$: {
-> 		const context = canvas.getContext('2d');
-> 		context.clearRect(0, 0, canvas.width, canvas.height);
->
-> 		// this will re-run whenever `color` or `size` change
-> 		context.fillStyle = color;
-> 		context.fillRect(0, 0, size, size);
-> 	}
-> </script>
->
-> <canvas bind:this={canvas} width="100" height="100" />
-> ```
->
-> This only worked at the top level of a component.
diff --git a/documentation/docs/03-template-syntax/xx-control-flow.md b/documentation/docs/03-template-syntax/xx-control-flow.md
deleted file mode 100644
index b73917997b..0000000000
--- a/documentation/docs/03-template-syntax/xx-control-flow.md
+++ /dev/null
@@ -1,111 +0,0 @@
----
-title: Control flow
----
-
-- if
-- each
-- await (or move that into some kind of data loading section?)
-- NOT: key (move into transition section, because that's the common use case)
-
-Svelte augments HTML with control flow blocks to be able to express conditionally rendered content or lists.
-
-The syntax between these blocks is the same:
-
-- `{#` denotes the start of a block
-- `{:` denotes a different branch part of the block. Depending on the block, there can be multiple of these
-- `{/` denotes the end of a block
-
-## {#if ...}
-
-## {#each ...}
-
-```svelte
-<!--- copy: false  --->
-{#each expression as name}...{/each}
-```
-
-```svelte
-<!--- copy: false  --->
-{#each expression as name, index}...{/each}
-```
-
-```svelte
-<!--- copy: false  --->
-{#each expression as name (key)}...{/each}
-```
-
-```svelte
-<!--- copy: false  --->
-{#each expression as name, index (key)}...{/each}
-```
-
-```svelte
-<!--- copy: false  --->
-{#each expression as name}...{:else}...{/each}
-```
-
-Iterating over lists of values can be done with an each block.
-
-```svelte
-<h1>Shopping list</h1>
-<ul>
-	{#each items as item}
-		<li>{item.name} x {item.qty}</li>
-	{/each}
-</ul>
-```
-
-You can use each blocks to iterate over any array or array-like value — that is, any object with a `length` property.
-
-An each block can also specify an _index_, equivalent to the second argument in an `array.map(...)` callback:
-
-```svelte
-{#each items as item, i}
-	<li>{i + 1}: {item.name} x {item.qty}</li>
-{/each}
-```
-
-If a _key_ expression is provided — which must uniquely identify each list item — Svelte will use it to diff the list when data changes, rather than adding or removing items at the end. The key can be any object, but strings and numbers are recommended since they allow identity to persist when the objects themselves change.
-
-```svelte
-{#each items as item (item.id)}
-	<li>{item.name} x {item.qty}</li>
-{/each}
-
-<!-- or with additional index value -->
-{#each items as item, i (item.id)}
-	<li>{i + 1}: {item.name} x {item.qty}</li>
-{/each}
-```
-
-You can freely use destructuring and rest patterns in each blocks.
-
-```svelte
-{#each items as { id, name, qty }, i (id)}
-	<li>{i + 1}: {name} x {qty}</li>
-{/each}
-
-{#each objects as { id, ...rest }}
-	<li><span>{id}</span><MyComponent {...rest} /></li>
-{/each}
-
-{#each items as [id, ...rest]}
-	<li><span>{id}</span><MyComponent values={rest} /></li>
-{/each}
-```
-
-An each block can also have an `{:else}` clause, which is rendered if the list is empty.
-
-```svelte
-{#each todos as todo}
-	<p>{todo.text}</p>
-{:else}
-	<p>No tasks today!</p>
-{/each}
-```
-
-It is possible to iterate over iterables like `Map` or `Set`. Iterables need to be finite and static (they shouldn't change while being iterated over). Under the hood, they are transformed to an array using `Array.from` before being passed off to rendering. If you're writing performance-sensitive code, try to avoid iterables and use regular arrays as they are more performant.
-
-## Other block types
-
-Svelte also provides [`#snippet`](snippets), [`#key`](transitions-and-animations) and [`#await`](data-fetching) blocks. You can find out more about them in their respective sections.
diff --git a/documentation/docs/03-template-syntax/xx-data-fetching.md b/documentation/docs/03-template-syntax/xx-data-fetching.md
deleted file mode 100644
index 4526d51335..0000000000
--- a/documentation/docs/03-template-syntax/xx-data-fetching.md
+++ /dev/null
@@ -1,20 +0,0 @@
----
-title: Data fetching
----
-
-Fetching data is a fundamental part of apps interacting with the outside world. Svelte is unopinionated with how you fetch your data. The simplest way would be using the built-in `fetch` method:
-
-```svelte
-<script>
-	let response = $state();
-	fetch('/api/data').then(async (r) => (response = r.json()));
-</script>
-```
-
-While this works, it makes working with promises somewhat unergonomic. Svelte alleviates this problem using the `#await` block.
-
-## {#await ...}
-
-## SvelteKit loaders
-
-Fetching inside your components is great for simple use cases, but it's prone to data loading waterfalls and makes code harder to work with because of the promise handling. SvelteKit solves this problem by providing a opinionated data loading story that is coupled to its router. Learn more about it [in the docs](../kit).
diff --git a/documentation/docs/07-misc/xx-reactivity-indepth.md b/documentation/docs/07-misc/xx-reactivity-indepth.md
deleted file mode 100644
index b40072552f..0000000000
--- a/documentation/docs/07-misc/xx-reactivity-indepth.md
+++ /dev/null
@@ -1,6 +0,0 @@
----
-title: Reactivity in depth
----
-
-- how to think about Runes ("just JavaScript" with added reactivity, what this means for keeping reactivity alive across boundaries)
-- signals

From fd57eb362ddf6e9e43936a7d098087f5e4720181 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Fri, 11 Apr 2025 17:16:49 -0400
Subject: [PATCH 13/27] Version Packages (#15737)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/stale-gorillas-judge.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/stale-gorillas-judge.md

diff --git a/.changeset/stale-gorillas-judge.md b/.changeset/stale-gorillas-judge.md
deleted file mode 100644
index 3d91f401dd..0000000000
--- a/.changeset/stale-gorillas-judge.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: update `state_referenced_locally` message
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 68a8803663..8b46efc94c 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,11 @@
 # svelte
 
+## 5.26.1
+
+### Patch Changes
+
+- fix: update `state_referenced_locally` message ([#15733](https://github.com/sveltejs/svelte/pull/15733))
+
 ## 5.26.0
 
 ### Minor Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 8267cb5218..a06c73429a 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": "5.26.0",
+  "version": "5.26.1",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index ade51aaf17..e5cb34ecd5 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 = '5.26.0';
+export const VERSION = '5.26.1';
 export const PUBLIC_VERSION = '5';

From d38504d073e9a6704660a4b98718b577975ce5d7 Mon Sep 17 00:00:00 2001
From: "dependabot[bot]" <49699333+dependabot[bot]@users.noreply.github.com>
Date: Fri, 11 Apr 2025 17:56:33 -0400
Subject: [PATCH 14/27] chore(deps-dev): bump vite from 5.4.17 to 5.4.18
 (#15743)

Bumps [vite](https://github.com/vitejs/vite/tree/HEAD/packages/vite) from 5.4.17 to 5.4.18.
- [Release notes](https://github.com/vitejs/vite/releases)
- [Changelog](https://github.com/vitejs/vite/blob/v5.4.18/packages/vite/CHANGELOG.md)
- [Commits](https://github.com/vitejs/vite/commits/v5.4.18/packages/vite)

---
updated-dependencies:
- dependency-name: vite
  dependency-version: 5.4.18
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
---
 playgrounds/sandbox/package.json |  2 +-
 pnpm-lock.yaml                   | 86 ++++++++++++++++----------------
 2 files changed, 44 insertions(+), 44 deletions(-)

diff --git a/playgrounds/sandbox/package.json b/playgrounds/sandbox/package.json
index d392349b60..5aee92ab17 100644
--- a/playgrounds/sandbox/package.json
+++ b/playgrounds/sandbox/package.json
@@ -18,7 +18,7 @@
     "polka": "^1.0.0-next.25",
     "svelte": "workspace:*",
     "tinyglobby": "^0.2.12",
-    "vite": "^5.4.17",
+    "vite": "^5.4.18",
     "vite-plugin-inspect": "^0.8.4"
   }
 }
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index f0e66d1681..3518b0e57e 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -152,7 +152,7 @@ importers:
     devDependencies:
       '@sveltejs/vite-plugin-svelte':
         specifier: ^4.0.0-next.6
-        version: 4.0.0-next.6(svelte@packages+svelte)(vite@5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+        version: 4.0.0-next.6(svelte@packages+svelte)(vite@5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
       polka:
         specifier: ^1.0.0-next.25
         version: 1.0.0-next.25
@@ -163,11 +163,11 @@ importers:
         specifier: ^0.2.12
         version: 0.2.12
       vite:
-        specifier: ^5.4.17
-        version: 5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+        specifier: ^5.4.18
+        version: 5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
       vite-plugin-inspect:
         specifier: ^0.8.4
-        version: 0.8.4(rollup@4.39.0)(vite@5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+        version: 0.8.4(rollup@4.39.0)(vite@5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
 
 packages:
 
@@ -816,8 +816,8 @@ packages:
     resolution: {integrity: sha512-E0ntLvsfPqnPwng8b8y4OGuzh/iIOm2z8U3S9zic2TeMLW61u5IH2Q1wu0oSTkfrSzwbDJIB/Lm8O3//8BWMPA==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
 
-  '@typescript-eslint/scope-manager@8.29.0':
-    resolution: {integrity: sha512-aO1PVsq7Gm+tcghabUpzEnVSFMCU4/nYIgC2GOatJcllvWfnhrgW0ZEbnTxm36QsikmCN1K/6ZgM7fok2I7xNw==}
+  '@typescript-eslint/scope-manager@8.29.1':
+    resolution: {integrity: sha512-2nggXGX5F3YrsGN08pw4XpMLO1Rgtnn4AzTegC2MDesv6q3QaTU5yU7IbS1tf1IwCR0Hv/1EFygLn9ms6LIpDA==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
 
   '@typescript-eslint/type-utils@8.26.0':
@@ -831,8 +831,8 @@ packages:
     resolution: {integrity: sha512-89B1eP3tnpr9A8L6PZlSjBvnJhWXtYfZhECqlBl1D9Lme9mHO6iWlsprBtVenQvY1HMhax1mWOjhtL3fh/u+pA==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
 
-  '@typescript-eslint/types@8.29.0':
-    resolution: {integrity: sha512-wcJL/+cOXV+RE3gjCyl/V2G877+2faqvlgtso/ZRbTCnZazh0gXhe+7gbAnfubzN2bNsBtZjDvlh7ero8uIbzg==}
+  '@typescript-eslint/types@8.29.1':
+    resolution: {integrity: sha512-VT7T1PuJF1hpYC3AGm2rCgJBjHL3nc+A/bhOp9sGMKfi5v0WufsX/sHCFBfNTx2F+zA6qBc/PD0/kLRLjdt8mQ==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
 
   '@typescript-eslint/typescript-estree@8.26.0':
@@ -841,8 +841,8 @@ packages:
     peerDependencies:
       typescript: '>=4.8.4 <5.9.0'
 
-  '@typescript-eslint/typescript-estree@8.29.0':
-    resolution: {integrity: sha512-yOfen3jE9ISZR/hHpU/bmNvTtBW1NjRbkSFdZOksL1N+ybPEE7UVGMwqvS6CP022Rp00Sb0tdiIkhSCe6NI8ow==}
+  '@typescript-eslint/typescript-estree@8.29.1':
+    resolution: {integrity: sha512-l1enRoSaUkQxOQnbi0KPUtqeZkSiFlqrx9/3ns2rEDhGKfTa+88RmXqedC1zmVTOWrLc2e6DEJrTA51C9iLH5g==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
       typescript: '>=4.8.4 <5.9.0'
@@ -854,8 +854,8 @@ packages:
       eslint: ^8.57.0 || ^9.0.0
       typescript: '>=4.8.4 <5.9.0'
 
-  '@typescript-eslint/utils@8.29.0':
-    resolution: {integrity: sha512-gX/A0Mz9Bskm8avSWFcK0gP7cZpbY4AIo6B0hWYFCaIsz750oaiWR4Jr2CI+PQhfW1CpcQr9OlfPS+kMFegjXA==}
+  '@typescript-eslint/utils@8.29.1':
+    resolution: {integrity: sha512-QAkFEbytSaB8wnmB+DflhUPz6CLbFWE2SnSCrRMEa+KnXIzDYbpsn++1HGvnfAsUY44doDXmvRkO5shlM/3UfA==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
     peerDependencies:
       eslint: ^8.57.0 || ^9.0.0
@@ -865,8 +865,8 @@ packages:
     resolution: {integrity: sha512-2z8JQJWAzPdDd51dRQ/oqIJxe99/hoLIqmf8RMCAJQtYDc535W/Jt2+RTP4bP0aKeBG1F65yjIZuczOXCmbWwg==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
 
-  '@typescript-eslint/visitor-keys@8.29.0':
-    resolution: {integrity: sha512-Sne/pVz8ryR03NFK21VpN88dZ2FdQXOlq3VIklbrTYEt8yXtRFr9tvUhqvCeKjqYk5FSim37sHbooT6vzBTZcg==}
+  '@typescript-eslint/visitor-keys@8.29.1':
+    resolution: {integrity: sha512-RGLh5CRaUEf02viP5c1Vh1cMGffQscyHe7HPAzGpfmfflFg1wUz2rYxd+OZqwpeypYvZ8UxSxuIpF++fmOzEcg==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
 
   '@vitest/coverage-v8@2.0.5':
@@ -2310,8 +2310,8 @@ packages:
       terser:
         optional: true
 
-  vite@5.4.17:
-    resolution: {integrity: sha512-5+VqZryDj4wgCs55o9Lp+p8GE78TLVg0lasCH5xFZ4jacZjtqZa6JUw9/p0WeAojaOfncSM6v77InkFPGnvPvg==}
+  vite@5.4.18:
+    resolution: {integrity: sha512-1oDcnEp3lVyHCuQ2YFelM4Alm2o91xNoMncRm1U7S+JdYfYOvbiGZ3/CxGttrOu2M/KcGz7cRC2DoNUA6urmMA==}
     engines: {node: ^18.0.0 || >=20.0.0}
     hasBin: true
     peerDependencies:
@@ -3000,25 +3000,25 @@ snapshots:
       typescript: 5.5.4
       typescript-eslint: 8.26.0(eslint@9.9.1)(typescript@5.5.4)
 
-  '@sveltejs/vite-plugin-svelte-inspector@3.0.0-next.2(@sveltejs/vite-plugin-svelte@4.0.0-next.6(svelte@packages+svelte)(vite@5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)))(svelte@packages+svelte)(vite@5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))':
+  '@sveltejs/vite-plugin-svelte-inspector@3.0.0-next.2(@sveltejs/vite-plugin-svelte@4.0.0-next.6(svelte@packages+svelte)(vite@5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)))(svelte@packages+svelte)(vite@5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))':
     dependencies:
-      '@sveltejs/vite-plugin-svelte': 4.0.0-next.6(svelte@packages+svelte)(vite@5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+      '@sveltejs/vite-plugin-svelte': 4.0.0-next.6(svelte@packages+svelte)(vite@5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
       debug: 4.4.0
       svelte: link:packages/svelte
-      vite: 5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+      vite: 5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
     transitivePeerDependencies:
       - supports-color
 
-  '@sveltejs/vite-plugin-svelte@4.0.0-next.6(svelte@packages+svelte)(vite@5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))':
+  '@sveltejs/vite-plugin-svelte@4.0.0-next.6(svelte@packages+svelte)(vite@5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))':
     dependencies:
-      '@sveltejs/vite-plugin-svelte-inspector': 3.0.0-next.2(@sveltejs/vite-plugin-svelte@4.0.0-next.6(svelte@packages+svelte)(vite@5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)))(svelte@packages+svelte)(vite@5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+      '@sveltejs/vite-plugin-svelte-inspector': 3.0.0-next.2(@sveltejs/vite-plugin-svelte@4.0.0-next.6(svelte@packages+svelte)(vite@5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)))(svelte@packages+svelte)(vite@5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
       debug: 4.4.0
       deepmerge: 4.3.1
       kleur: 4.1.5
       magic-string: 0.30.17
       svelte: link:packages/svelte
-      vite: 5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
-      vitefu: 0.2.5(vite@5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
+      vite: 5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+      vitefu: 0.2.5(vite@5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))
     transitivePeerDependencies:
       - supports-color
 
@@ -3088,10 +3088,10 @@ snapshots:
       '@typescript-eslint/types': 8.26.0
       '@typescript-eslint/visitor-keys': 8.26.0
 
-  '@typescript-eslint/scope-manager@8.29.0':
+  '@typescript-eslint/scope-manager@8.29.1':
     dependencies:
-      '@typescript-eslint/types': 8.29.0
-      '@typescript-eslint/visitor-keys': 8.29.0
+      '@typescript-eslint/types': 8.29.1
+      '@typescript-eslint/visitor-keys': 8.29.1
 
   '@typescript-eslint/type-utils@8.26.0(eslint@9.9.1)(typescript@5.5.4)':
     dependencies:
@@ -3106,7 +3106,7 @@ snapshots:
 
   '@typescript-eslint/types@8.26.0': {}
 
-  '@typescript-eslint/types@8.29.0': {}
+  '@typescript-eslint/types@8.29.1': {}
 
   '@typescript-eslint/typescript-estree@8.26.0(typescript@5.5.4)':
     dependencies:
@@ -3122,10 +3122,10 @@ snapshots:
     transitivePeerDependencies:
       - supports-color
 
-  '@typescript-eslint/typescript-estree@8.29.0(typescript@5.5.4)':
+  '@typescript-eslint/typescript-estree@8.29.1(typescript@5.5.4)':
     dependencies:
-      '@typescript-eslint/types': 8.29.0
-      '@typescript-eslint/visitor-keys': 8.29.0
+      '@typescript-eslint/types': 8.29.1
+      '@typescript-eslint/visitor-keys': 8.29.1
       debug: 4.4.0
       fast-glob: 3.3.3
       is-glob: 4.0.3
@@ -3147,12 +3147,12 @@ snapshots:
     transitivePeerDependencies:
       - supports-color
 
-  '@typescript-eslint/utils@8.29.0(eslint@9.9.1)(typescript@5.5.4)':
+  '@typescript-eslint/utils@8.29.1(eslint@9.9.1)(typescript@5.5.4)':
     dependencies:
       '@eslint-community/eslint-utils': 4.5.1(eslint@9.9.1)
-      '@typescript-eslint/scope-manager': 8.29.0
-      '@typescript-eslint/types': 8.29.0
-      '@typescript-eslint/typescript-estree': 8.29.0(typescript@5.5.4)
+      '@typescript-eslint/scope-manager': 8.29.1
+      '@typescript-eslint/types': 8.29.1
+      '@typescript-eslint/typescript-estree': 8.29.1(typescript@5.5.4)
       eslint: 9.9.1
       typescript: 5.5.4
     transitivePeerDependencies:
@@ -3163,9 +3163,9 @@ snapshots:
       '@typescript-eslint/types': 8.26.0
       eslint-visitor-keys: 4.2.0
 
-  '@typescript-eslint/visitor-keys@8.29.0':
+  '@typescript-eslint/visitor-keys@8.29.1':
     dependencies:
-      '@typescript-eslint/types': 8.29.0
+      '@typescript-eslint/types': 8.29.1
       eslint-visitor-keys: 4.2.0
 
   '@vitest/coverage-v8@2.0.5(vitest@2.1.9(@types/node@20.12.7)(jsdom@25.0.1)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0))':
@@ -3509,7 +3509,7 @@ snapshots:
   eslint-plugin-n@17.16.1(eslint@9.9.1)(typescript@5.5.4):
     dependencies:
       '@eslint-community/eslint-utils': 4.5.1(eslint@9.9.1)
-      '@typescript-eslint/utils': 8.29.0(eslint@9.9.1)(typescript@5.5.4)
+      '@typescript-eslint/utils': 8.29.1(eslint@9.9.1)(typescript@5.5.4)
       enhanced-resolve: 5.18.1
       eslint: 9.9.1
       eslint-plugin-es-x: 7.8.0(eslint@9.9.1)
@@ -4562,7 +4562,7 @@ snapshots:
       debug: 4.4.0
       es-module-lexer: 1.6.0
       pathe: 1.1.2
-      vite: 5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+      vite: 5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
     transitivePeerDependencies:
       - '@types/node'
       - less
@@ -4574,7 +4574,7 @@ snapshots:
       - supports-color
       - terser
 
-  vite-plugin-inspect@0.8.4(rollup@4.39.0)(vite@5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
+  vite-plugin-inspect@0.8.4(rollup@4.39.0)(vite@5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
     dependencies:
       '@antfu/utils': 0.7.8
       '@rollup/pluginutils': 5.1.0(rollup@4.39.0)
@@ -4585,7 +4585,7 @@ snapshots:
       perfect-debounce: 1.0.0
       picocolors: 1.1.1
       sirv: 2.0.4
-      vite: 5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+      vite: 5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
     transitivePeerDependencies:
       - rollup
       - supports-color
@@ -4602,7 +4602,7 @@ snapshots:
       sass: 1.70.0
       terser: 5.27.0
 
-  vite@5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0):
+  vite@5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0):
     dependencies:
       esbuild: 0.21.5
       postcss: 8.5.3
@@ -4614,9 +4614,9 @@ snapshots:
       sass: 1.70.0
       terser: 5.27.0
 
-  vitefu@0.2.5(vite@5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
+  vitefu@0.2.5(vite@5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)):
     optionalDependencies:
-      vite: 5.4.17(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
+      vite: 5.4.18(@types/node@20.12.7)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0)
 
   vitest@2.1.9(@types/node@20.12.7)(jsdom@25.0.1)(lightningcss@1.23.0)(sass@1.70.0)(terser@5.27.0):
     dependencies:

From a5240ccfe48ecc2f9eebf3de45ffcd60825bc1b0 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 11 Apr 2025 18:49:38 -0400
Subject: [PATCH 15/27] use pnpm/action-setup (#15744)

---
 .github/workflows/pkg.pr.new.yml | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/pkg.pr.new.yml b/.github/workflows/pkg.pr.new.yml
index b2b521dc6f..b1ba217e5a 100644
--- a/.github/workflows/pkg.pr.new.yml
+++ b/.github/workflows/pkg.pr.new.yml
@@ -8,10 +8,8 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - name: Checkout code
-        uses: actions/checkout@v4
-
-      - run: corepack enable
+      - uses: actions/checkout@v4
+      - uses: pnpm/action-setup@v4
       - uses: actions/setup-node@v4
         with:
           node-version: 22.x

From 3d6da41b1d3aaf80b5e9cb9aa8aaa1f91ffc485b Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 11 Apr 2025 22:19:01 -0400
Subject: [PATCH 16/27] chore: remove some unused code (#15747)

---
 .../svelte/src/internal/client/reactivity/sources.js     | 3 +--
 packages/svelte/src/internal/client/runtime.js           | 9 +--------
 2 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/packages/svelte/src/internal/client/reactivity/sources.js b/packages/svelte/src/internal/client/reactivity/sources.js
index 27e8fd824d..69a41338c0 100644
--- a/packages/svelte/src/internal/client/reactivity/sources.js
+++ b/packages/svelte/src/internal/client/reactivity/sources.js
@@ -1,4 +1,4 @@
-/** @import { Derived, Effect, Reaction, Source, Value } from '#client' */
+/** @import { Derived, Effect, Source, Value } from '#client' */
 import { DEV } from 'esm-env';
 import {
 	active_reaction,
@@ -12,7 +12,6 @@ import {
 	increment_write_version,
 	update_effect,
 	reaction_sources,
-	set_reaction_sources,
 	check_dirtiness,
 	untracking,
 	is_destroying_effect,
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index a7662be617..2acad3d258 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -94,18 +94,11 @@ export function set_active_effect(effect) {
  */
 export let reaction_sources = null;
 
-/**
- * @param {Source[] | null} sources
- */
-export function set_reaction_sources(sources) {
-	reaction_sources = sources;
-}
-
 /** @param {Value} value */
 export function push_reaction_value(value) {
 	if (active_reaction !== null && active_reaction.f & EFFECT_IS_UPDATING) {
 		if (reaction_sources === null) {
-			set_reaction_sources([value]);
+			reaction_sources = [value];
 		} else {
 			reaction_sources.push(value);
 		}

From 69a427518dc4eeae39ec8be8c55486d0093784df Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Sat, 12 Apr 2025 16:39:22 +0200
Subject: [PATCH 17/27] fix: correctly validate `undefined` snippet params with
 default value (#15750)

* fix: correctly validate `undefined` snippet params with default value

* use arguments

* unused

* drive-by

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/angry-mayflies-matter.md           |  5 +++
 .../client/visitors/SnippetBlock.js           | 34 ++++++-------------
 .../_config.js                                |  5 +++
 .../main.svelte                               |  5 +++
 4 files changed, 25 insertions(+), 24 deletions(-)
 create mode 100644 .changeset/angry-mayflies-matter.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/validate-undefined-snippet-default-arg/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/validate-undefined-snippet-default-arg/main.svelte

diff --git a/.changeset/angry-mayflies-matter.md b/.changeset/angry-mayflies-matter.md
new file mode 100644
index 0000000000..289fbf87b6
--- /dev/null
+++ b/.changeset/angry-mayflies-matter.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: correctly validate `undefined` snippet params with default value
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 7eb043aa5d..f28f8c8a59 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
@@ -21,6 +21,10 @@ export function SnippetBlock(node, context) {
 	/** @type {Statement[]} */
 	const declarations = [];
 
+	if (dev) {
+		declarations.push(b.stmt(b.call('$.validate_snippet_args', b.spread(b.id('arguments')))));
+	}
+
 	const transform = { ...context.state.transform };
 	const child_state = { ...context.state, transform };
 
@@ -30,12 +34,7 @@ export function SnippetBlock(node, context) {
 		if (!argument) continue;
 
 		if (argument.type === 'Identifier') {
-			args.push({
-				type: 'AssignmentPattern',
-				left: argument,
-				right: b.id('$.noop')
-			});
-
+			args.push(b.assignment_pattern(argument, b.id('$.noop')));
 			transform[argument.name] = { read: b.call };
 
 			continue;
@@ -66,29 +65,16 @@ export function SnippetBlock(node, context) {
 			}
 		}
 	}
-	if (dev) {
-		declarations.unshift(
-			b.stmt(
-				b.call(
-					'$.validate_snippet_args',
-					.../** @type {Identifier[]} */ (
-						args.map((arg) => (arg?.type === 'Identifier' ? arg : arg?.left))
-					)
-				)
-			)
-		);
-	}
+
 	body = b.block([
 		...declarations,
 		.../** @type {BlockStatement} */ (context.visit(node.body, child_state)).body
 	]);
 
-	/** @type {Expression} */
-	let snippet = b.arrow(args, body);
-
-	if (dev) {
-		snippet = b.call('$.wrap_snippet', b.id(context.state.analysis.name), snippet);
-	}
+	// in dev we use a FunctionExpression (not arrow function) so we can use `arguments`
+	let snippet = dev
+		? b.call('$.wrap_snippet', b.id(context.state.analysis.name), b.function(null, args, body))
+		: b.arrow(args, body);
 
 	const declaration = b.const(node.expression, snippet);
 
diff --git a/packages/svelte/tests/runtime-runes/samples/validate-undefined-snippet-default-arg/_config.js b/packages/svelte/tests/runtime-runes/samples/validate-undefined-snippet-default-arg/_config.js
new file mode 100644
index 0000000000..bddb75e677
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/validate-undefined-snippet-default-arg/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	html: `<p>default</p>`
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/validate-undefined-snippet-default-arg/main.svelte b/packages/svelte/tests/runtime-runes/samples/validate-undefined-snippet-default-arg/main.svelte
new file mode 100644
index 0000000000..3f00eba46b
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/validate-undefined-snippet-default-arg/main.svelte
@@ -0,0 +1,5 @@
+{#snippet test(param = "default")}
+    <p>{param}</p>
+{/snippet}
+
+{@render test()}
\ No newline at end of file

From 3153384928c444b484fd504268ba87aa580396a1 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Sat, 12 Apr 2025 10:42:58 -0400
Subject: [PATCH 18/27] Version Packages (#15751)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/angry-mayflies-matter.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/angry-mayflies-matter.md

diff --git a/.changeset/angry-mayflies-matter.md b/.changeset/angry-mayflies-matter.md
deleted file mode 100644
index 289fbf87b6..0000000000
--- a/.changeset/angry-mayflies-matter.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: correctly validate `undefined` snippet params with default value
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 8b46efc94c..3c876880b8 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,11 @@
 # svelte
 
+## 5.26.2
+
+### Patch Changes
+
+- fix: correctly validate `undefined` snippet params with default value ([#15750](https://github.com/sveltejs/svelte/pull/15750))
+
 ## 5.26.1
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index a06c73429a..75568f4a77 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": "5.26.1",
+  "version": "5.26.2",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index e5cb34ecd5..2dc75f7e59 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 = '5.26.1';
+export const VERSION = '5.26.2';
 export const PUBLIC_VERSION = '5';

From fd0bc2997340bb8164e2b77996e81645315b8c5d Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Sun, 13 Apr 2025 12:20:48 +0200
Subject: [PATCH 19/27] fix: correctly validate head snippets on the server
 (#15755)

* fix: correctly validate head snippets on the server

* put the logic in copy_payload so it gets treeshaken in most cases

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/dirty-zebras-do.md                 |  5 +++
 packages/svelte/src/internal/server/dev.js    |  8 +++--
 .../svelte/src/internal/server/payload.js     | 34 ++++++++++++-------
 .../head-payload-validation/_config.js        | 11 ++++++
 .../head-payload-validation/main.svelte       |  7 ++++
 5 files changed, 50 insertions(+), 15 deletions(-)
 create mode 100644 .changeset/dirty-zebras-do.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/head-payload-validation/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/head-payload-validation/main.svelte

diff --git a/.changeset/dirty-zebras-do.md b/.changeset/dirty-zebras-do.md
new file mode 100644
index 0000000000..f0b266b09c
--- /dev/null
+++ b/.changeset/dirty-zebras-do.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: correctly validate head snippets on the server
diff --git a/packages/svelte/src/internal/server/dev.js b/packages/svelte/src/internal/server/dev.js
index 34849196b7..157f22f929 100644
--- a/packages/svelte/src/internal/server/dev.js
+++ b/packages/svelte/src/internal/server/dev.js
@@ -6,7 +6,7 @@ import {
 } from '../../html-tree-validation.js';
 import { current_component } from './context.js';
 import { invalid_snippet_arguments } from '../shared/errors.js';
-import { Payload } from './payload.js';
+import { HeadPayload, Payload } from './payload.js';
 
 /**
  * @typedef {{
@@ -105,7 +105,11 @@ export function pop_element() {
  * @param {Payload} payload
  */
 export function validate_snippet_args(payload) {
-	if (typeof payload !== 'object' || !(payload instanceof Payload)) {
+	if (
+		typeof payload !== 'object' ||
+		// for some reason typescript consider the type of payload as never after the first instanceof
+		!(payload instanceof Payload || /** @type {any} */ (payload) instanceof HeadPayload)
+	) {
 		invalid_snippet_arguments();
 	}
 }
diff --git a/packages/svelte/src/internal/server/payload.js b/packages/svelte/src/internal/server/payload.js
index 03bcaf492e..8df5787ba4 100644
--- a/packages/svelte/src/internal/server/payload.js
+++ b/packages/svelte/src/internal/server/payload.js
@@ -1,16 +1,25 @@
+export class HeadPayload {
+	/** @type {Set<{ hash: string; code: string }>} */
+	css = new Set();
+	out = '';
+	uid = () => '';
+	title = '';
+
+	constructor(css = new Set(), out = '', title = '', uid = () => '') {
+		this.css = css;
+		this.out = out;
+		this.title = title;
+		this.uid = uid;
+	}
+}
+
 export class Payload {
 	/** @type {Set<{ hash: string; code: string }>} */
 	css = new Set();
 	out = '';
 	uid = () => '';
 
-	head = {
-		/** @type {Set<{ hash: string; code: string }>} */
-		css: new Set(),
-		title: '',
-		out: '',
-		uid: () => ''
-	};
+	head = new HeadPayload();
 
 	constructor(id_prefix = '') {
 		this.uid = props_id_generator(id_prefix);
@@ -30,12 +39,11 @@ export function copy_payload({ out, css, head, uid }) {
 	payload.css = new Set(css);
 	payload.uid = uid;
 
-	payload.head = {
-		title: head.title,
-		out: head.out,
-		css: new Set(head.css),
-		uid: head.uid
-	};
+	payload.head = new HeadPayload();
+	payload.head.out = head.out;
+	payload.head.css = new Set(head.css);
+	payload.head.title = head.title;
+	payload.head.uid = head.uid;
 
 	return payload;
 }
diff --git a/packages/svelte/tests/runtime-runes/samples/head-payload-validation/_config.js b/packages/svelte/tests/runtime-runes/samples/head-payload-validation/_config.js
new file mode 100644
index 0000000000..7c609205df
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/head-payload-validation/_config.js
@@ -0,0 +1,11 @@
+import { test } from '../../test';
+
+export default test({
+	compileOptions: {
+		dev: true
+	},
+	mode: ['server'],
+	async test({ errors, assert }) {
+		assert.equal(errors, []);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/head-payload-validation/main.svelte b/packages/svelte/tests/runtime-runes/samples/head-payload-validation/main.svelte
new file mode 100644
index 0000000000..7eb31d3a9e
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/head-payload-validation/main.svelte
@@ -0,0 +1,7 @@
+{#snippet head()}
+	<title>Cool</title>
+{/snippet}
+
+<svelte:head>
+	{@render head()}
+</svelte:head>
\ No newline at end of file

From de4376235cb355d818ba7aaa17c00a4fe76fe9cd Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Mon, 14 Apr 2025 07:02:58 -0400
Subject: [PATCH 20/27] docs: add some missing details around string coercion
 and handling of nullish values (#15739)

closes #14716
---
 documentation/docs/02-runes/05-$props.md                 | 4 ++--
 documentation/docs/03-template-syntax/01-basic-markup.md | 2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/documentation/docs/02-runes/05-$props.md b/documentation/docs/02-runes/05-$props.md
index f300fb239d..222b4831b6 100644
--- a/documentation/docs/02-runes/05-$props.md
+++ b/documentation/docs/02-runes/05-$props.md
@@ -37,7 +37,7 @@ On the other side, inside `MyComponent.svelte`, we can receive props with the `$
 
 ## Fallback values
 
-Destructuring allows us to declare fallback values, which are used if the parent component does not set a given prop:
+Destructuring allows us to declare fallback values, which are used if the parent component does not set a given prop (or the value is `undefined`):
 
 ```js
 let { adjective = 'happy' } = $props();
@@ -219,4 +219,4 @@ This is useful for linking elements via attributes like `for` and `aria-labelled
 	<label for="{uid}-lastname">Last Name: </label>
 	<input id="{uid}-lastname" type="text" />
 </form>
-```
\ No newline at end of file
+```
diff --git a/documentation/docs/03-template-syntax/01-basic-markup.md b/documentation/docs/03-template-syntax/01-basic-markup.md
index 5e8b4342d3..fe5f8b02aa 100644
--- a/documentation/docs/03-template-syntax/01-basic-markup.md
+++ b/documentation/docs/03-template-syntax/01-basic-markup.md
@@ -154,6 +154,8 @@ A JavaScript expression can be included as text by surrounding it with curly bra
 {expression}
 ```
 
+Expressions that are `null` or `undefined` will be omitted; all others are [coerced to strings](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String#string_coercion).
+
 Curly braces can be included in a Svelte template by using their [HTML entity](https://developer.mozilla.org/docs/Glossary/Entity) strings: `&lbrace;`, `&lcub;`, or `&#123;` for `{` and `&rbrace;`, `&rcub;`, or `&#125;` for `}`.
 
 If you're using a regular expression (`RegExp`) [literal notation](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp#literal_notation_and_constructor), you'll need to wrap it in parentheses.

From bdf033e30f40b7b40792eafe694a02ce84387089 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Mon, 14 Apr 2025 14:56:43 +0200
Subject: [PATCH 21/27] fix: allow self-closing tags within math namespace
 (#15761)

fixes #15757
---
 .changeset/wicked-cheetahs-juggle.md                      | 5 +++++
 .../compiler/phases/2-analyze/visitors/RegularElement.js  | 3 ++-
 .../samples/invalid-self-closing-tag/input.svelte         | 1 +
 .../samples/invalid-self-closing-tag/warnings.json        | 8 ++++----
 4 files changed, 12 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/wicked-cheetahs-juggle.md

diff --git a/.changeset/wicked-cheetahs-juggle.md b/.changeset/wicked-cheetahs-juggle.md
new file mode 100644
index 0000000000..58dca62bec
--- /dev/null
+++ b/.changeset/wicked-cheetahs-juggle.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: allow self-closing tags within math namespace
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 03dfaebcb7..d5689e5d55 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/RegularElement.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/RegularElement.js
@@ -173,7 +173,8 @@ export function RegularElement(node, context) {
 	if (
 		context.state.analysis.source[node.end - 2] === '/' &&
 		!is_void(node_name) &&
-		!is_svg(node_name)
+		!is_svg(node_name) &&
+		!is_mathml(node_name)
 	) {
 		w.element_invalid_self_closing_tag(node, node.name);
 	}
diff --git a/packages/svelte/tests/validator/samples/invalid-self-closing-tag/input.svelte b/packages/svelte/tests/validator/samples/invalid-self-closing-tag/input.svelte
index 376c9f79bd..07582e8343 100644
--- a/packages/svelte/tests/validator/samples/invalid-self-closing-tag/input.svelte
+++ b/packages/svelte/tests/validator/samples/invalid-self-closing-tag/input.svelte
@@ -1,6 +1,7 @@
 <!-- valid -->
 <link />
 <svg><g /></svg>
+<math><mspace /></math>
 <enhanced:img />
 
 
diff --git a/packages/svelte/tests/validator/samples/invalid-self-closing-tag/warnings.json b/packages/svelte/tests/validator/samples/invalid-self-closing-tag/warnings.json
index 40b87ec7c8..3e45bca5ad 100644
--- a/packages/svelte/tests/validator/samples/invalid-self-closing-tag/warnings.json
+++ b/packages/svelte/tests/validator/samples/invalid-self-closing-tag/warnings.json
@@ -3,11 +3,11 @@
 		"code": "element_invalid_self_closing_tag",
 		"message": "Self-closing HTML tags for non-void elements are ambiguous — use `<div ...></div>` rather than `<div ... />`",
 		"start": {
-			"line": 8,
+			"line": 9,
 			"column": 0
 		},
 		"end": {
-			"line": 8,
+			"line": 9,
 			"column": 7
 		}
 	},
@@ -15,11 +15,11 @@
 		"code": "element_invalid_self_closing_tag",
 		"message": "Self-closing HTML tags for non-void elements are ambiguous — use `<my-thing ...></my-thing>` rather than `<my-thing ... />`",
 		"start": {
-			"line": 9,
+			"line": 10,
 			"column": 0
 		},
 		"end": {
-			"line": 9,
+			"line": 10,
 			"column": 12
 		}
 	}

From 26e574f27f6866383044a85da9d6845944bd0fe2 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Mon, 14 Apr 2025 14:57:37 +0200
Subject: [PATCH 22/27] fix: ignore mutation validation for props that are not
 proxies in more cases (#15759)

This fixes an off-by-one error - we did not bail if the top level of the prop wasn't a state already. Fixes #15727
---
 .changeset/modern-ducks-reflect.md            |  5 +++++
 .../src/internal/client/dev/ownership.js      |  7 ++++---
 .../samples/non-local-mutation-ok/_config.js  | 18 ++++++++++++++++
 .../non-local-mutation-ok/child.svelte        |  8 +++++++
 .../samples/non-local-mutation-ok/main.svelte | 21 +++++++++++++++++++
 5 files changed, 56 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/modern-ducks-reflect.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/non-local-mutation-ok/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/non-local-mutation-ok/child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/non-local-mutation-ok/main.svelte

diff --git a/.changeset/modern-ducks-reflect.md b/.changeset/modern-ducks-reflect.md
new file mode 100644
index 0000000000..dfbb9a18cc
--- /dev/null
+++ b/.changeset/modern-ducks-reflect.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: ignore mutation validation for props that are not proxies in more cases
diff --git a/packages/svelte/src/internal/client/dev/ownership.js b/packages/svelte/src/internal/client/dev/ownership.js
index 108c7adf92..5a8af6d522 100644
--- a/packages/svelte/src/internal/client/dev/ownership.js
+++ b/packages/svelte/src/internal/client/dev/ownership.js
@@ -31,13 +31,14 @@ export function create_ownership_validator(props) {
 				return result;
 			}
 
-			let value = props[name];
+			/** @type {any} */
+			let value = props;
 
-			for (let i = 1; i < path.length - 1; i++) {
+			for (let i = 0; i < path.length - 1; i++) {
+				value = value[path[i]];
 				if (!value?.[STATE_SYMBOL]) {
 					return result;
 				}
-				value = value[path[i]];
 			}
 
 			const location = sanitize_location(`${component[FILENAME]}:${line}:${column}`);
diff --git a/packages/svelte/tests/runtime-runes/samples/non-local-mutation-ok/_config.js b/packages/svelte/tests/runtime-runes/samples/non-local-mutation-ok/_config.js
new file mode 100644
index 0000000000..437385e185
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/non-local-mutation-ok/_config.js
@@ -0,0 +1,18 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	compileOptions: {
+		dev: true
+	},
+
+	test({ assert, target, warnings }) {
+		const btn = target.querySelector('button');
+		btn?.click();
+		flushSync();
+
+		assert.deepEqual(warnings, []);
+	},
+
+	warnings: []
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/non-local-mutation-ok/child.svelte b/packages/svelte/tests/runtime-runes/samples/non-local-mutation-ok/child.svelte
new file mode 100644
index 0000000000..0243a6c7d1
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/non-local-mutation-ok/child.svelte
@@ -0,0 +1,8 @@
+<script>
+	let { klass, getter_setter } = $props();
+</script>
+
+<button onclick={() => {
+	klass.y = 2;
+	getter_setter.y = 2;
+}}>mutate</button>
diff --git a/packages/svelte/tests/runtime-runes/samples/non-local-mutation-ok/main.svelte b/packages/svelte/tests/runtime-runes/samples/non-local-mutation-ok/main.svelte
new file mode 100644
index 0000000000..8685664ab1
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/non-local-mutation-ok/main.svelte
@@ -0,0 +1,21 @@
+<script>
+	import Child from './child.svelte';
+
+	class X {
+		y = $state(1);
+	}
+
+	const klass = new X();
+
+	let y = $state(1);
+	const getter_setter = {
+		get y() {
+			return y;
+		},
+		set y(value) {
+			y = value;
+		}
+	}
+</script>
+
+<Child {klass}  {getter_setter} />

From db111f61ea51edd655b13a0949dc696bb8688d81 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Mon, 14 Apr 2025 09:08:19 -0400
Subject: [PATCH 23/27] docs: headers for snippet prop section (#15745)

Closes #14020
Closes #15172
---
 documentation/docs/03-template-syntax/06-snippet.md | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/documentation/docs/03-template-syntax/06-snippet.md b/documentation/docs/03-template-syntax/06-snippet.md
index c9951d3f34..ab536c6e5c 100644
--- a/documentation/docs/03-template-syntax/06-snippet.md
+++ b/documentation/docs/03-template-syntax/06-snippet.md
@@ -112,6 +112,8 @@ Snippets can reference themselves and each other ([demo](/playground/untitled#H4
 
 ## Passing snippets to components
 
+### Explicit props
+
 Within the template, snippets are values just like any other. As such, they can be passed to components as props ([demo](/playground/untitled#H4sIAAAAAAAAE3VS247aMBD9lZGpBGwDASRegonaPvQL2qdlH5zYEKvBNvbQLbL875VzAcKyj3PmzJnLGU8UOwqSkd8KJdaCk4TsZS0cyV49wYuJuQiQpGd-N2bu_ooaI1YwJ57hpVYoFDqSEepKKw3mO7VDeTTaIvxiRS1gb_URxvO0ibrS8WanIrHUyiHs7Vmigy28RmyHHmKvDMbMmFq4cQInvGSwTsBYWYoMVhCSB2rBFFPsyl0uruTlR3JZCWvlTXl1Yy_mawiR_rbZKZrellJ-5JQ0RiBUgnFhJ9OGR7HKmwVoilXeIye8DOJGfYCgRlZ3iE876TBsZPX7hPdteO75PC4QaIo8vwNPePmANQ2fMeEFHrLD7rR1jTNkW986E8C3KwfwVr8HSHOSEBT_kGRozyIkn_zQveXDL3rIfPJHtUDwzShJd_Qk3gQCbOGLsdq4yfTRJopRuin3I7nv6kL7ARRjmLdBDG3uv1mhuLA3V2mKtqNEf_oCn8p9aN-WYqH5peP4kWBl1UwJzAEPT9U7K--0fRrrWnPTXpCm1_EVdXjpNmlA8G1hPPyM1fKgMqjFHjctXGjLhZ05w0qpDhksGrybuNEHtJnCalZWsuaTlfq6nPaaBSv_HKw-K57BjzOiVj9ZKQYKzQjZodYFqydYTRN4gPhVzTDO2xnma3HsVWjaLjT8nbfwHy7Q5f2dBAAA)):
 
 ```svelte
@@ -144,6 +146,8 @@ Within the template, snippets are values just like any other. As such, they can
 
 Think about it like passing content instead of data to a component. The concept is similar to slots in web components.
 
+### Implicit props
+
 As an authoring convenience, snippets declared directly _inside_ a component implicitly become props _on_ the component ([demo](/playground/untitled#H4sIAAAAAAAAE3VSTa_aMBD8Kyu_SkAbCA-JSzBR20N_QXt6vIMTO8SqsY29tI2s_PcqTiB8vaPHs7MzuxuIZgdBMvJLo0QlOElIJZXwJHsLBBvb_XUASc7Mb9Yu_B-hsMMK5sUzvDQahUZPMkJ96aTFfKd3KA_WOISfrFACKmcOMFmk8TWUTjY73RFLoz1C5U4SPWzhrcN2GKDrlcGEWauEnyRwxCaDdQLWyVJksII2uaMWTDPNLtzX5YX8-kgua-GcHJVXI3u5WEPb0d83O03TMZSmfRzOkG1Db7mNacOL19JagVALxoWbztq-H8U6j0SaYp2P2BGbOyQ2v8PQIFMXLKRDk177pq0zf6d8bMrzwBdd0pamyPMb-IjNEzS2f86Gz_Dwf-2F9nvNSUJQ_EOSoTuJNvngqK5v4Pas7n4-OCwlEEJcQTIMO-nSQwtb-GSdsX46e9gbRoP9yGQ11I0rEuycunu6PHx1QnPhxm3SFN15MOlYEFJZtf0dUywMbwZOeBGsrKNLYB54-1R9WNqVdki7usim6VmQphf7mnpshiQRhNAXdoOfMyX3OgMlKtz0cGEcF27uLSul3mewjPjgOOoDukxjPS9rqfh0pb-8zs6aBSt_7505aZ7B9xOi0T9YKW4UooVsr0zB1BTrWQJ3EL-oWcZ572GxFoezCk37QLe3897-B2i2U62uBAAA)):
 
 ```svelte
@@ -165,6 +169,8 @@ As an authoring convenience, snippets declared directly _inside_ a component imp
 </Table>
 ```
 
+### Implicit `children` snippet
+
 Any content inside the component tags that is _not_ a snippet declaration implicitly becomes part of the `children` snippet ([demo](/playground/untitled#H4sIAAAAAAAAE3WOQQrCMBBFrzIMggql3ddY1Du4si5sOmIwnYRkFKX07lKqglqX8_7_w2uRDw1hjlsWI5ZqTPBoLEXMdy3K3fdZDzB5Ndfep_FKVnpWHSKNce1YiCVijirqYLwUJQOYxrsgsLmIOIZjcA1M02w4n-PpomSVvTclqyEutDX6DA2pZ7_ABIVugrmEC3XJH92P55_G39GodCmWBFrQJ2PrQAwdLGHig_NxNv9xrQa1dhWIawrv1Wzeqawa8953D-8QOmaEAQAA)):
 
 ```svelte
@@ -184,6 +190,8 @@ Any content inside the component tags that is _not_ a snippet declaration implic
 
 > [!NOTE] Note that you cannot have a prop called `children` if you also have content inside the component — for this reason, you should avoid having props with that name
 
+### Optional snippet props
+
 You can declare snippet props as being optional. You can either use optional chaining to not render anything if the snippet isn't set...
 
 ```svelte

From 7aed6beeaabbcdbaa0a6fab952c6e06a0b385edd Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Mon, 14 Apr 2025 09:12:10 -0400
Subject: [PATCH 24/27] Version Packages (#15756)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/dirty-zebras-do.md        |  5 -----
 .changeset/modern-ducks-reflect.md   |  5 -----
 .changeset/wicked-cheetahs-juggle.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/dirty-zebras-do.md
 delete mode 100644 .changeset/modern-ducks-reflect.md
 delete mode 100644 .changeset/wicked-cheetahs-juggle.md

diff --git a/.changeset/dirty-zebras-do.md b/.changeset/dirty-zebras-do.md
deleted file mode 100644
index f0b266b09c..0000000000
--- a/.changeset/dirty-zebras-do.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: correctly validate head snippets on the server
diff --git a/.changeset/modern-ducks-reflect.md b/.changeset/modern-ducks-reflect.md
deleted file mode 100644
index dfbb9a18cc..0000000000
--- a/.changeset/modern-ducks-reflect.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: ignore mutation validation for props that are not proxies in more cases
diff --git a/.changeset/wicked-cheetahs-juggle.md b/.changeset/wicked-cheetahs-juggle.md
deleted file mode 100644
index 58dca62bec..0000000000
--- a/.changeset/wicked-cheetahs-juggle.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: allow self-closing tags within math namespace
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 3c876880b8..58f2317796 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,15 @@
 # svelte
 
+## 5.26.3
+
+### Patch Changes
+
+- fix: correctly validate head snippets on the server ([#15755](https://github.com/sveltejs/svelte/pull/15755))
+
+- fix: ignore mutation validation for props that are not proxies in more cases ([#15759](https://github.com/sveltejs/svelte/pull/15759))
+
+- fix: allow self-closing tags within math namespace ([#15761](https://github.com/sveltejs/svelte/pull/15761))
+
 ## 5.26.2
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index 75568f4a77..b8654671ec 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": "5.26.2",
+  "version": "5.26.3",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 2dc75f7e59..1909588146 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 = '5.26.2';
+export const VERSION = '5.26.3';
 export const PUBLIC_VERSION = '5';

From a051f96ed607751f502dadcd9cbaff1bf880b15f Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Mon, 14 Apr 2025 20:38:02 +0200
Subject: [PATCH 25/27] fix: relax `:global` selector list validation (#15762)

We have to allow `:global x, :global y` selector lists because CSS preprocessors might generate that from `:global { x, y {...} }`
---
 .changeset/green-starfishes-shave.md          |  5 ++
 .../98-reference/.generated/compile-errors.md | 26 +++++-
 .../svelte/messages/compile-errors/style.md   | 26 +++++-
 packages/svelte/src/compiler/errors.js        |  4 +-
 .../phases/2-analyze/css/css-analyze.js       | 90 +++++++++----------
 .../compiler/phases/3-transform/css/index.js  | 37 +++++---
 .../css-global-block-multiple-1/_config.js    | 10 +++
 .../css-global-block-multiple-1/main.svelte   |  9 ++
 .../css-global-block-multiple-2/_config.js    | 10 +++
 .../css-global-block-multiple-2/main.svelte   |  6 ++
 .../css-global-block-multiple/_config.js      |  9 --
 .../css-global-block-multiple/main.svelte     |  3 -
 .../tests/css/samples/global-block/_config.js | 14 +++
 .../css/samples/global-block/expected.css     | 10 +++
 .../css/samples/global-block/input.svelte     | 10 +++
 15 files changed, 198 insertions(+), 71 deletions(-)
 create mode 100644 .changeset/green-starfishes-shave.md
 create mode 100644 packages/svelte/tests/compiler-errors/samples/css-global-block-multiple-1/_config.js
 create mode 100644 packages/svelte/tests/compiler-errors/samples/css-global-block-multiple-1/main.svelte
 create mode 100644 packages/svelte/tests/compiler-errors/samples/css-global-block-multiple-2/_config.js
 create mode 100644 packages/svelte/tests/compiler-errors/samples/css-global-block-multiple-2/main.svelte
 delete mode 100644 packages/svelte/tests/compiler-errors/samples/css-global-block-multiple/_config.js
 delete mode 100644 packages/svelte/tests/compiler-errors/samples/css-global-block-multiple/main.svelte

diff --git a/.changeset/green-starfishes-shave.md b/.changeset/green-starfishes-shave.md
new file mode 100644
index 0000000000..967bba753c
--- /dev/null
+++ b/.changeset/green-starfishes-shave.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: relax `:global` selector list validation
diff --git a/documentation/docs/98-reference/.generated/compile-errors.md b/documentation/docs/98-reference/.generated/compile-errors.md
index a8c39aaf97..6196a85ade 100644
--- a/documentation/docs/98-reference/.generated/compile-errors.md
+++ b/documentation/docs/98-reference/.generated/compile-errors.md
@@ -235,7 +235,31 @@ A top-level `:global {...}` block can only contain rules, not declarations
 ### css_global_block_invalid_list
 
 ```
-A `:global` selector cannot be part of a selector list with more than one item
+A `:global` selector cannot be part of a selector list with entries that don't contain `:global`
+```
+
+The following CSS is invalid:
+
+```css
+:global, x {
+    y {
+        color: red;
+    }
+}
+```
+
+This is mixing a `:global` block, which means "everything in here is unscoped", with a scoped selector (`x` in this case). As a result it's not possible to transform the inner selector (`y` in this case) into something that satisfies both requirements. You therefore have to split this up into two selectors:
+
+```css
+:global {
+    y {
+        color: red;
+    }
+}
+
+x y {
+    color: red;
+}
 ```
 
 ### css_global_block_invalid_modifier
diff --git a/packages/svelte/messages/compile-errors/style.md b/packages/svelte/messages/compile-errors/style.md
index 1e1ab45e8c..f08a2156a3 100644
--- a/packages/svelte/messages/compile-errors/style.md
+++ b/packages/svelte/messages/compile-errors/style.md
@@ -16,7 +16,31 @@
 
 ## css_global_block_invalid_list
 
-> A `:global` selector cannot be part of a selector list with more than one item
+> A `:global` selector cannot be part of a selector list with entries that don't contain `:global`
+
+The following CSS is invalid:
+
+```css
+:global, x {
+    y {
+        color: red;
+    }
+}
+```
+
+This is mixing a `:global` block, which means "everything in here is unscoped", with a scoped selector (`x` in this case). As a result it's not possible to transform the inner selector (`y` in this case) into something that satisfies both requirements. You therefore have to split this up into two selectors:
+
+```css
+:global {
+    y {
+        color: red;
+    }
+}
+
+x y {
+    color: red;
+}
+```
 
 ## css_global_block_invalid_modifier
 
diff --git a/packages/svelte/src/compiler/errors.js b/packages/svelte/src/compiler/errors.js
index 6bf973948b..aa328764e1 100644
--- a/packages/svelte/src/compiler/errors.js
+++ b/packages/svelte/src/compiler/errors.js
@@ -555,12 +555,12 @@ export function css_global_block_invalid_declaration(node) {
 }
 
 /**
- * A `:global` selector cannot be part of a selector list with more than one item
+ * A `:global` selector cannot be part of a selector list with entries that don't contain `:global`
  * @param {null | number | NodeLike} node
  * @returns {never}
  */
 export function css_global_block_invalid_list(node) {
-	e(node, 'css_global_block_invalid_list', `A \`:global\` selector cannot be part of a selector list with more than one item\nhttps://svelte.dev/e/css_global_block_invalid_list`);
+	e(node, 'css_global_block_invalid_list', `A \`:global\` selector cannot be part of a selector list with entries that don't contain \`:global\`\nhttps://svelte.dev/e/css_global_block_invalid_list`);
 }
 
 /**
diff --git a/packages/svelte/src/compiler/phases/2-analyze/css/css-analyze.js b/packages/svelte/src/compiler/phases/2-analyze/css/css-analyze.js
index 76cb2f56e9..2dc3435648 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/css/css-analyze.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/css/css-analyze.js
@@ -193,10 +193,12 @@ const css_visitors = {
 	Rule(node, context) {
 		node.metadata.parent_rule = context.state.rule;
 
-		node.metadata.is_global_block = node.prelude.children.some((selector) => {
+		// We gotta allow :global x, :global y because CSS preprocessors might generate that from :global { x, y {...} }
+		for (const complex_selector of node.prelude.children) {
 			let is_global_block = false;
 
-			for (const child of selector.children) {
+			for (let selector_idx = 0; selector_idx < complex_selector.children.length; selector_idx++) {
+				const child = complex_selector.children[selector_idx];
 				const idx = child.selectors.findIndex(is_global_block_selector);
 
 				if (is_global_block) {
@@ -204,58 +206,56 @@ const css_visitors = {
 					child.metadata.is_global_like = true;
 				}
 
-				if (idx !== -1) {
-					is_global_block = true;
+				if (idx === 0) {
+					if (
+						child.selectors.length > 1 &&
+						selector_idx === 0 &&
+						node.metadata.parent_rule === null
+					) {
+						e.css_global_block_invalid_modifier_start(child.selectors[1]);
+					} else {
+						// `child` starts with `:global`
+						node.metadata.is_global_block = is_global_block = true;
+
+						for (let i = 1; i < child.selectors.length; i++) {
+							walk(/** @type {AST.CSS.Node} */ (child.selectors[i]), null, {
+								ComplexSelector(node) {
+									node.metadata.used = true;
+								}
+							});
+						}
 
-					for (let i = idx + 1; i < child.selectors.length; i++) {
-						walk(/** @type {AST.CSS.Node} */ (child.selectors[i]), null, {
-							ComplexSelector(node) {
-								node.metadata.used = true;
-							}
-						});
-					}
-				}
-			}
+						if (child.combinator && child.combinator.name !== ' ') {
+							e.css_global_block_invalid_combinator(child, child.combinator.name);
+						}
 
-			return is_global_block;
-		});
+						const declaration = node.block.children.find((child) => child.type === 'Declaration');
+						const is_lone_global =
+							complex_selector.children.length === 1 &&
+							complex_selector.children[0].selectors.length === 1; // just `:global`, not e.g. `:global x`
 
-		if (node.metadata.is_global_block) {
-			if (node.prelude.children.length > 1) {
-				e.css_global_block_invalid_list(node.prelude);
-			}
+						if (is_lone_global && node.prelude.children.length > 1) {
+							// `:global, :global x { z { ... } }` would become `x { z { ... } }` which means `z` is always
+							// constrained by `x`, which is not what the user intended
+							e.css_global_block_invalid_list(node.prelude);
+						}
 
-			const complex_selector = node.prelude.children[0];
-			const global_selector = complex_selector.children.find((r, selector_idx) => {
-				const idx = r.selectors.findIndex(is_global_block_selector);
-				if (idx === 0) {
-					if (r.selectors.length > 1 && selector_idx === 0 && node.metadata.parent_rule === null) {
-						e.css_global_block_invalid_modifier_start(r.selectors[1]);
+						if (
+							declaration &&
+							// :global { color: red; } is invalid, but foo :global { color: red; } is valid
+							node.prelude.children.length === 1 &&
+							is_lone_global
+						) {
+							e.css_global_block_invalid_declaration(declaration);
+						}
 					}
-					return true;
 				} else if (idx !== -1) {
-					e.css_global_block_invalid_modifier(r.selectors[idx]);
+					e.css_global_block_invalid_modifier(child.selectors[idx]);
 				}
-			});
-
-			if (!global_selector) {
-				throw new Error('Internal error: global block without :global selector');
-			}
-
-			if (global_selector.combinator && global_selector.combinator.name !== ' ') {
-				e.css_global_block_invalid_combinator(global_selector, global_selector.combinator.name);
 			}
 
-			const declaration = node.block.children.find((child) => child.type === 'Declaration');
-
-			if (
-				declaration &&
-				// :global { color: red; } is invalid, but foo :global { color: red; } is valid
-				node.prelude.children.length === 1 &&
-				node.prelude.children[0].children.length === 1 &&
-				node.prelude.children[0].children[0].selectors.length === 1
-			) {
-				e.css_global_block_invalid_declaration(declaration);
+			if (node.metadata.is_global_block && !is_global_block) {
+				e.css_global_block_invalid_list(node.prelude);
 			}
 		}
 
diff --git a/packages/svelte/src/compiler/phases/3-transform/css/index.js b/packages/svelte/src/compiler/phases/3-transform/css/index.js
index dff034f8aa..9f1142cce9 100644
--- a/packages/svelte/src/compiler/phases/3-transform/css/index.js
+++ b/packages/svelte/src/compiler/phases/3-transform/css/index.js
@@ -170,7 +170,11 @@ const visitors = {
 		if (node.metadata.is_global_block) {
 			const selector = node.prelude.children[0];
 
-			if (selector.children.length === 1 && selector.children[0].selectors.length === 1) {
+			if (
+				node.prelude.children.length === 1 &&
+				selector.children.length === 1 &&
+				selector.children[0].selectors.length === 1
+			) {
 				// `:global {...}`
 				if (state.minify) {
 					state.code.remove(node.start, node.block.start + 1);
@@ -194,7 +198,7 @@ const visitors = {
 	SelectorList(node, { state, next, path }) {
 		// Only add comments if we're not inside a complex selector that itself is unused or a global block
 		if (
-			!is_in_global_block(path) &&
+			(!is_in_global_block(path) || node.children.length > 1) &&
 			!path.find((n) => n.type === 'ComplexSelector' && !n.metadata.used)
 		) {
 			const children = node.children;
@@ -282,13 +286,24 @@ const visitors = {
 				const global = /** @type {AST.CSS.PseudoClassSelector} */ (relative_selector.selectors[0]);
 				remove_global_pseudo_class(global, relative_selector.combinator, context.state);
 
-				if (
-					node.metadata.rule?.metadata.parent_rule &&
-					global.args === null &&
-					relative_selector.combinator === null
-				) {
-					// div { :global.x { ... } } becomes div { &.x { ... } }
-					context.state.code.prependRight(global.start, '&');
+				const parent_rule = node.metadata.rule?.metadata.parent_rule;
+				if (parent_rule && global.args === null) {
+					if (relative_selector.combinator === null) {
+						// div { :global.x { ... } } becomes div { &.x { ... } }
+						context.state.code.prependRight(global.start, '&');
+					}
+
+					// In case of multiple :global selectors in a selector list we gotta delete the comma, too, but only if
+					// the next selector is used; if it's unused then the comma deletion happens as part of removal of that next selector
+					if (
+						parent_rule.prelude.children.length > 1 &&
+						node.children.length === node.children.findIndex((s) => s === relative_selector) - 1
+					) {
+						const next_selector = parent_rule.prelude.children.find((s) => s.start > global.end);
+						if (next_selector && next_selector.metadata.used) {
+							context.state.code.update(global.end, next_selector.start, '');
+						}
+					}
 				}
 				continue;
 			} else {
@@ -380,7 +395,9 @@ function remove_global_pseudo_class(selector, combinator, state) {
 			// div :global.x becomes div.x
 			while (/\s/.test(state.code.original[start - 1])) start--;
 		}
-		state.code.remove(start, selector.start + ':global'.length);
+
+		// update(...), not remove(...) because there could be a closing unused comment at the end
+		state.code.update(start, selector.start + ':global'.length, '');
 	} else {
 		state.code
 			.remove(selector.start, selector.start + ':global('.length)
diff --git a/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple-1/_config.js b/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple-1/_config.js
new file mode 100644
index 0000000000..85dedc8012
--- /dev/null
+++ b/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple-1/_config.js
@@ -0,0 +1,10 @@
+import { test } from '../../test';
+
+export default test({
+	error: {
+		code: 'css_global_block_invalid_list',
+		message:
+			"A `:global` selector cannot be part of a selector list with entries that don't contain `:global`",
+		position: [232, 246]
+	}
+});
diff --git a/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple-1/main.svelte b/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple-1/main.svelte
new file mode 100644
index 0000000000..260921f704
--- /dev/null
+++ b/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple-1/main.svelte
@@ -0,0 +1,9 @@
+<style>
+	/* valid */
+	/* We gotta allow `:global x, :global y` and the likes because CSS preprocessors might generate that from e.g. `:global { x, y {...} }` */
+	:global .x, :global .y {}
+	.x :global, .y :global {}
+
+	/* invalid */
+	.x :global, .y {}
+</style>
diff --git a/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple-2/_config.js b/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple-2/_config.js
new file mode 100644
index 0000000000..f24095800a
--- /dev/null
+++ b/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple-2/_config.js
@@ -0,0 +1,10 @@
+import { test } from '../../test';
+
+export default test({
+	error: {
+		code: 'css_global_block_invalid_list',
+		message:
+			"A `:global` selector cannot be part of a selector list with entries that don't contain `:global`",
+		position: [24, 43]
+	}
+});
diff --git a/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple-2/main.svelte b/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple-2/main.svelte
new file mode 100644
index 0000000000..2a09ec10ce
--- /dev/null
+++ b/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple-2/main.svelte
@@ -0,0 +1,6 @@
+<style>
+	/* invalid */
+	:global, :global .y {
+		z { color: red }
+	}
+</style>
diff --git a/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple/_config.js b/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple/_config.js
deleted file mode 100644
index 9ae4e758c4..0000000000
--- a/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple/_config.js
+++ /dev/null
@@ -1,9 +0,0 @@
-import { test } from '../../test';
-
-export default test({
-	error: {
-		code: 'css_global_block_invalid_list',
-		message: 'A `:global` selector cannot be part of a selector list with more than one item',
-		position: [9, 31]
-	}
-});
diff --git a/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple/main.svelte b/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple/main.svelte
deleted file mode 100644
index 75178bc664..0000000000
--- a/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple/main.svelte
+++ /dev/null
@@ -1,3 +0,0 @@
-<style>
-	.x :global, .y :global {}
-</style>
diff --git a/packages/svelte/tests/css/samples/global-block/_config.js b/packages/svelte/tests/css/samples/global-block/_config.js
index bee0d7204d..a8b11a73ec 100644
--- a/packages/svelte/tests/css/samples/global-block/_config.js
+++ b/packages/svelte/tests/css/samples/global-block/_config.js
@@ -16,6 +16,20 @@ export default test({
 				column: 16,
 				character: 932
 			}
+		},
+		{
+			code: 'css_unused_selector',
+			message: 'Unused CSS selector "unused :global"',
+			start: {
+				line: 100,
+				column: 29,
+				character: 1223
+			},
+			end: {
+				line: 100,
+				column: 43,
+				character: 1237
+			}
 		}
 	]
 });
diff --git a/packages/svelte/tests/css/samples/global-block/expected.css b/packages/svelte/tests/css/samples/global-block/expected.css
index 438749224b..12f9a75032 100644
--- a/packages/svelte/tests/css/samples/global-block/expected.css
+++ b/packages/svelte/tests/css/samples/global-block/expected.css
@@ -90,3 +90,13 @@
 			opacity: 1;
 		}
 	}
+
+	 x,  y {
+		color: green;
+	}
+
+	div.svelte-xyz, div.svelte-xyz y /* (unused) unused*/ {
+		z {
+			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 a1833636a1..ee05205d67 100644
--- a/packages/svelte/tests/css/samples/global-block/input.svelte
+++ b/packages/svelte/tests/css/samples/global-block/input.svelte
@@ -92,4 +92,14 @@
 			opacity: 1;
 		}
 	}
+
+	:global x, :global y {
+		color: green;
+	}
+
+	div :global, div :global y, unused :global {
+		z {
+			color: green;
+		}
+	}
 </style>

From 90563e903fd8428db4c087b6fa4f51e0200dbb45 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Mon, 14 Apr 2025 14:38:31 -0400
Subject: [PATCH 26/27] feat: add partial evaluation (#15494)

* feat: add partial evaluation

* fix

* tweak

* more

* more

* evaluate stuff in template

* update test

* SSR

* unused

* changeset

* remove TODO

* Apply suggestions from code review

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

* allow unknown operators

* use blocks and block-scoping in switch statement

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---
 .changeset/selfish-onions-begin.md            |   5 +
 .../client/visitors/RegularElement.js         |   9 +-
 .../client/visitors/shared/utils.js           |  26 +-
 .../server/visitors/shared/utils.js           |  16 +-
 packages/svelte/src/compiler/phases/scope.js  | 322 +++++++++++++++++-
 .../_expected/client/index.svelte.js          |   6 +-
 .../_expected/server/index.svelte.js          |   2 +-
 .../_expected/client/index.svelte.js          |   2 +-
 .../samples/attached-sourcemap/input.svelte   |   2 +-
 9 files changed, 357 insertions(+), 33 deletions(-)
 create mode 100644 .changeset/selfish-onions-begin.md

diff --git a/.changeset/selfish-onions-begin.md b/.changeset/selfish-onions-begin.md
new file mode 100644
index 0000000000..decf0d5fc6
--- /dev/null
+++ b/.changeset/selfish-onions-begin.md
@@ -0,0 +1,5 @@
+---
+'svelte': minor
+---
+
+feat: partially evaluate certain expressions
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 45a594af1f..fa4ee9867f 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
@@ -685,14 +685,13 @@ function build_element_special_value_attribute(element, node_id, attribute, cont
 			: value
 	);
 
+	const evaluated = context.state.scope.evaluate(value);
+	const assignment = b.assignment('=', b.member(node_id, '__value'), value);
+
 	const inner_assignment = b.assignment(
 		'=',
 		b.member(node_id, 'value'),
-		b.conditional(
-			b.binary('==', b.null, b.assignment('=', b.member(node_id, '__value'), value)),
-			b.literal(''), // render null/undefined values as empty string to support placeholder options
-			value
-		)
+		evaluated.is_defined ? assignment : b.logical('??', assignment, b.literal(''))
 	);
 
 	const update = b.stmt(
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 af6e56f70c..55362d75af 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
@@ -89,21 +89,21 @@ export function build_template_chunk(
 				}
 			}
 
-			const is_defined =
-				value.type === 'BinaryExpression' ||
-				(value.type === 'UnaryExpression' && value.operator !== 'void') ||
-				(value.type === 'LogicalExpression' && value.right.type === 'Literal') ||
-				(value.type === 'Identifier' && value.name === state.analysis.props_id?.name);
-
-			if (!is_defined) {
-				// add `?? ''` where necessary (TODO optimise more cases)
-				value = b.logical('??', value, b.literal(''));
-			}
+			const evaluated = state.scope.evaluate(value);
 
-			expressions.push(value);
+			if (evaluated.is_known) {
+				quasi.value.cooked += evaluated.value + '';
+			} else {
+				if (!evaluated.is_defined) {
+					// add `?? ''` where necessary
+					value = b.logical('??', value, b.literal(''));
+				}
 
-			quasi = b.quasi('', i + 1 === values.length);
-			quasis.push(quasi);
+				expressions.push(value);
+
+				quasi = b.quasi('', i + 1 === values.length);
+				quasis.push(quasi);
+			}
 		}
 	}
 
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 2c6aa2f316..807e12a8fa 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
@@ -44,15 +44,17 @@ export function process_children(nodes, { visit, state }) {
 			if (node.type === 'Text' || node.type === 'Comment') {
 				quasi.value.cooked +=
 					node.type === 'Comment' ? `<!--${node.data}-->` : escape_html(node.data);
-			} else if (node.type === 'ExpressionTag' && node.expression.type === 'Literal') {
-				if (node.expression.value != null) {
-					quasi.value.cooked += escape_html(node.expression.value + '');
-				}
 			} else {
-				expressions.push(b.call('$.escape', /** @type {Expression} */ (visit(node.expression))));
+				const evaluated = state.scope.evaluate(node.expression);
+
+				if (evaluated.is_known) {
+					quasi.value.cooked += escape_html((evaluated.value ?? '') + '');
+				} else {
+					expressions.push(b.call('$.escape', /** @type {Expression} */ (visit(node.expression))));
 
-				quasi = b.quasi('', i + 1 === sequence.length);
-				quasis.push(quasi);
+					quasi = b.quasi('', i + 1 === sequence.length);
+					quasis.push(quasi);
+				}
 			}
 		}
 
diff --git a/packages/svelte/src/compiler/phases/scope.js b/packages/svelte/src/compiler/phases/scope.js
index b6063c3234..73dfeea1d9 100644
--- a/packages/svelte/src/compiler/phases/scope.js
+++ b/packages/svelte/src/compiler/phases/scope.js
@@ -1,4 +1,4 @@
-/** @import { ArrowFunctionExpression, ClassDeclaration, Expression, FunctionDeclaration, FunctionExpression, Identifier, ImportDeclaration, MemberExpression, Node, Pattern, VariableDeclarator } from 'estree' */
+/** @import { ArrowFunctionExpression, BinaryOperator, ClassDeclaration, Expression, FunctionDeclaration, FunctionExpression, Identifier, ImportDeclaration, MemberExpression, LogicalOperator, Node, Pattern, UnaryOperator, VariableDeclarator } from 'estree' */
 /** @import { Context, Visitor } from 'zimmerframe' */
 /** @import { AST, BindingKind, DeclarationKind } from '#compiler' */
 import is_reference from 'is-reference';
@@ -16,6 +16,11 @@ import { is_reserved, is_rune } from '../../utils.js';
 import { determine_slot } from '../utils/slot.js';
 import { validate_identifier_name } from './2-analyze/visitors/shared/utils.js';
 
+export const UNKNOWN = Symbol('unknown');
+/** Includes `BigInt` */
+export const NUMBER = Symbol('number');
+export const STRING = Symbol('string');
+
 export class Binding {
 	/** @type {Scope} */
 	scope;
@@ -34,7 +39,7 @@ export class Binding {
 	 * For destructured props such as `let { foo = 'bar' } = $props()` this is `'bar'` and not `$props()`
 	 * @type {null | Expression | FunctionDeclaration | ClassDeclaration | ImportDeclaration | AST.EachBlock | AST.SnippetBlock}
 	 */
-	initial;
+	initial = null;
 
 	/** @type {Array<{ node: Identifier; path: AST.SvelteNode[] }>} */
 	references = [];
@@ -100,6 +105,264 @@ export class Binding {
 	}
 }
 
+class Evaluation {
+	/** @type {Set<any>} */
+	values = new Set();
+
+	/**
+	 * True if there is exactly one possible value
+	 * @readonly
+	 * @type {boolean}
+	 */
+	is_known = true;
+
+	/**
+	 * True if the value is known to not be null/undefined
+	 * @readonly
+	 * @type {boolean}
+	 */
+	is_defined = true;
+
+	/**
+	 * True if the value is known to be a string
+	 * @readonly
+	 * @type {boolean}
+	 */
+	is_string = true;
+
+	/**
+	 * True if the value is known to be a number
+	 * @readonly
+	 * @type {boolean}
+	 */
+	is_number = true;
+
+	/**
+	 * @readonly
+	 * @type {any}
+	 */
+	value = undefined;
+
+	/**
+	 *
+	 * @param {Scope} scope
+	 * @param {Expression} expression
+	 */
+	constructor(scope, expression) {
+		switch (expression.type) {
+			case 'Literal': {
+				this.values.add(expression.value);
+				break;
+			}
+
+			case 'Identifier': {
+				const binding = scope.get(expression.name);
+
+				if (binding) {
+					if (
+						binding.initial?.type === 'CallExpression' &&
+						get_rune(binding.initial, scope) === '$props.id'
+					) {
+						this.values.add(STRING);
+						break;
+					}
+
+					const is_prop =
+						binding.kind === 'prop' ||
+						binding.kind === 'rest_prop' ||
+						binding.kind === 'bindable_prop';
+
+					if (!binding.updated && binding.initial !== null && !is_prop) {
+						const evaluation = binding.scope.evaluate(/** @type {Expression} */ (binding.initial));
+						for (const value of evaluation.values) {
+							this.values.add(value);
+						}
+						break;
+					}
+
+					// TODO each index is always defined
+				}
+
+				// TODO glean what we can from reassignments
+				// TODO one day, expose props and imports somehow
+
+				this.values.add(UNKNOWN);
+				break;
+			}
+
+			case 'BinaryExpression': {
+				const a = scope.evaluate(/** @type {Expression} */ (expression.left)); // `left` cannot be `PrivateIdentifier` unless operator is `in`
+				const b = scope.evaluate(expression.right);
+
+				if (a.is_known && b.is_known) {
+					this.values.add(binary[expression.operator](a.value, b.value));
+					break;
+				}
+
+				switch (expression.operator) {
+					case '!=':
+					case '!==':
+					case '<':
+					case '<=':
+					case '>':
+					case '>=':
+					case '==':
+					case '===':
+					case 'in':
+					case 'instanceof':
+						this.values.add(true);
+						this.values.add(false);
+						break;
+
+					case '%':
+					case '&':
+					case '*':
+					case '**':
+					case '-':
+					case '/':
+					case '<<':
+					case '>>':
+					case '>>>':
+					case '^':
+					case '|':
+						this.values.add(NUMBER);
+						break;
+
+					case '+':
+						if (a.is_string || b.is_string) {
+							this.values.add(STRING);
+						} else if (a.is_number && b.is_number) {
+							this.values.add(NUMBER);
+						} else {
+							this.values.add(STRING);
+							this.values.add(NUMBER);
+						}
+						break;
+
+					default:
+						this.values.add(UNKNOWN);
+				}
+				break;
+			}
+
+			case 'ConditionalExpression': {
+				const test = scope.evaluate(expression.test);
+				const consequent = scope.evaluate(expression.consequent);
+				const alternate = scope.evaluate(expression.alternate);
+
+				if (test.is_known) {
+					for (const value of (test.value ? consequent : alternate).values) {
+						this.values.add(value);
+					}
+				} else {
+					for (const value of consequent.values) {
+						this.values.add(value);
+					}
+
+					for (const value of alternate.values) {
+						this.values.add(value);
+					}
+				}
+				break;
+			}
+
+			case 'LogicalExpression': {
+				const a = scope.evaluate(expression.left);
+				const b = scope.evaluate(expression.right);
+
+				if (a.is_known) {
+					if (b.is_known) {
+						this.values.add(logical[expression.operator](a.value, b.value));
+						break;
+					}
+
+					if (
+						(expression.operator === '&&' && !a.value) ||
+						(expression.operator === '||' && a.value) ||
+						(expression.operator === '??' && a.value != null)
+					) {
+						this.values.add(a.value);
+					} else {
+						for (const value of b.values) {
+							this.values.add(value);
+						}
+					}
+
+					break;
+				}
+
+				for (const value of a.values) {
+					this.values.add(value);
+				}
+
+				for (const value of b.values) {
+					this.values.add(value);
+				}
+				break;
+			}
+
+			case 'UnaryExpression': {
+				const argument = scope.evaluate(expression.argument);
+
+				if (argument.is_known) {
+					this.values.add(unary[expression.operator](argument.value));
+					break;
+				}
+
+				switch (expression.operator) {
+					case '!':
+					case 'delete':
+						this.values.add(false);
+						this.values.add(true);
+						break;
+
+					case '+':
+					case '-':
+					case '~':
+						this.values.add(NUMBER);
+						break;
+
+					case 'typeof':
+						this.values.add(STRING);
+						break;
+
+					case 'void':
+						this.values.add(undefined);
+						break;
+
+					default:
+						this.values.add(UNKNOWN);
+				}
+				break;
+			}
+
+			default: {
+				this.values.add(UNKNOWN);
+			}
+		}
+
+		for (const value of this.values) {
+			this.value = value; // saves having special logic for `size === 1`
+
+			if (value !== STRING && typeof value !== 'string') {
+				this.is_string = false;
+			}
+
+			if (value !== NUMBER && typeof value !== 'number') {
+				this.is_number = false;
+			}
+
+			if (value == null || value === UNKNOWN) {
+				this.is_defined = false;
+			}
+		}
+
+		if (this.values.size > 1 || typeof this.value === 'symbol') {
+			this.is_known = false;
+		}
+	}
+}
+
 export class Scope {
 	/** @type {ScopeRoot} */
 	root;
@@ -279,8 +542,63 @@ export class Scope {
 			this.root.conflicts.add(node.name);
 		}
 	}
+
+	/**
+	 * Does partial evaluation to find an exact value or at least the rough type of the expression.
+	 * Only call this once scope has been fully generated in a first pass,
+	 * else this evaluates on incomplete data and may yield wrong results.
+	 * @param {Expression} expression
+	 * @param {Set<any>} values
+	 */
+	evaluate(expression, values = new Set()) {
+		return new Evaluation(this, expression);
+	}
 }
 
+/** @type {Record<BinaryOperator, (left: any, right: any) => any>} */
+const binary = {
+	'!=': (left, right) => left != right,
+	'!==': (left, right) => left !== right,
+	'<': (left, right) => left < right,
+	'<=': (left, right) => left <= right,
+	'>': (left, right) => left > right,
+	'>=': (left, right) => left >= right,
+	'==': (left, right) => left == right,
+	'===': (left, right) => left === right,
+	in: (left, right) => left in right,
+	instanceof: (left, right) => left instanceof right,
+	'%': (left, right) => left % right,
+	'&': (left, right) => left & right,
+	'*': (left, right) => left * right,
+	'**': (left, right) => left ** right,
+	'+': (left, right) => left + right,
+	'-': (left, right) => left - right,
+	'/': (left, right) => left / right,
+	'<<': (left, right) => left << right,
+	'>>': (left, right) => left >> right,
+	'>>>': (left, right) => left >>> right,
+	'^': (left, right) => left ^ right,
+	'|': (left, right) => left | right
+};
+
+/** @type {Record<UnaryOperator, (argument: any) => any>} */
+const unary = {
+	'-': (argument) => -argument,
+	'+': (argument) => +argument,
+	'!': (argument) => !argument,
+	'~': (argument) => ~argument,
+	typeof: (argument) => typeof argument,
+	void: () => undefined,
+	delete: () => true
+};
+
+/** @type {Record<LogicalOperator, (left: any, right: any) => any>} */
+const logical = {
+	'||': (left, right) => left || right,
+	'&&': (left, right) => left && right,
+	'??': (left, right) => left ?? right
+};
+
 export class ScopeRoot {
 	/** @type {Set<string>} */
 	conflicts = new Set();
diff --git a/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/client/index.svelte.js
index 332c909ebe..21f6ed9680 100644
--- a/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/client/index.svelte.js
@@ -10,11 +10,11 @@ export default function Nullish_coallescence_omittance($$anchor) {
 	var fragment = root();
 	var h1 = $.first_child(fragment);
 
-	h1.textContent = `Hello, ${name ?? ''}!`;
+	h1.textContent = 'Hello, world!';
 
 	var b = $.sibling(h1, 2);
 
-	b.textContent = `${1 ?? 'stuff'}${2 ?? 'more stuff'}${3 ?? 'even more stuff'}`;
+	b.textContent = '123';
 
 	var button = $.sibling(b, 2);
 
@@ -26,7 +26,7 @@ export default function Nullish_coallescence_omittance($$anchor) {
 
 	var h1_1 = $.sibling(button, 2);
 
-	h1_1.textContent = `Hello, ${name ?? 'earth' ?? ''}`;
+	h1_1.textContent = 'Hello, world';
 	$.template_effect(() => $.set_text(text, `Count is ${$.get(count) ?? ''}`));
 	$.append($$anchor, fragment);
 }
diff --git a/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/server/index.svelte.js
index 8181bfd98e..3b23befcd4 100644
--- a/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/nullish-coallescence-omittance/_expected/server/index.svelte.js
@@ -4,5 +4,5 @@ export default function Nullish_coallescence_omittance($$payload) {
 	let name = 'world';
 	let count = 0;
 
-	$$payload.out += `<h1>Hello, ${$.escape(name)}!</h1> <b>${$.escape(1 ?? 'stuff')}${$.escape(2 ?? 'more stuff')}${$.escape(3 ?? 'even more stuff')}</b> <button>Count is ${$.escape(count)}</button> <h1>Hello, ${$.escape(name ?? 'earth' ?? null)}</h1>`;
+	$$payload.out += `<h1>Hello, world!</h1> <b>123</b> <button>Count is ${$.escape(count)}</button> <h1>Hello, world</h1>`;
 }
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/client/index.svelte.js
index 46d376aca2..b341d39f28 100644
--- a/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/client/index.svelte.js
@@ -38,7 +38,7 @@ export default function Skip_static_subtree($$anchor, $$props) {
 	var select = $.sibling(div_1, 2);
 	var option = $.child(select);
 
-	option.value = null == (option.__value = 'a') ? '' : 'a';
+	option.value = option.__value = 'a';
 	$.reset(select);
 
 	var img = $.sibling(select, 2);
diff --git a/packages/svelte/tests/sourcemaps/samples/attached-sourcemap/input.svelte b/packages/svelte/tests/sourcemaps/samples/attached-sourcemap/input.svelte
index 21a47a72a9..715bbda8d9 100644
--- a/packages/svelte/tests/sourcemaps/samples/attached-sourcemap/input.svelte
+++ b/packages/svelte/tests/sourcemaps/samples/attached-sourcemap/input.svelte
@@ -8,4 +8,4 @@
 		replace_me_script = 'hello'
 	;
 </script>
-<h1 class="done_replace_style_2">{done_replace_script_2}</h1>
+<h1 class="done_replace_style_2">{Math.random() < 1 && done_replace_script_2}</h1>

From 6a7e53feaa53425624a47d7ebed98ff8d6fb1d8b Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Mon, 14 Apr 2025 22:23:50 -0400
Subject: [PATCH 27/27] Version Packages (#15764)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 .changeset/green-starfishes-shave.md |  5 -----
 .changeset/selfish-onions-begin.md   |  5 -----
 packages/svelte/CHANGELOG.md         | 10 ++++++++++
 packages/svelte/package.json         |  2 +-
 packages/svelte/src/version.js       |  2 +-
 5 files changed, 12 insertions(+), 12 deletions(-)
 delete mode 100644 .changeset/green-starfishes-shave.md
 delete mode 100644 .changeset/selfish-onions-begin.md

diff --git a/.changeset/green-starfishes-shave.md b/.changeset/green-starfishes-shave.md
deleted file mode 100644
index 967bba753c..0000000000
--- a/.changeset/green-starfishes-shave.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': patch
----
-
-fix: relax `:global` selector list validation
diff --git a/.changeset/selfish-onions-begin.md b/.changeset/selfish-onions-begin.md
deleted file mode 100644
index decf0d5fc6..0000000000
--- a/.changeset/selfish-onions-begin.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'svelte': minor
----
-
-feat: partially evaluate certain expressions
diff --git a/packages/svelte/CHANGELOG.md b/packages/svelte/CHANGELOG.md
index 58f2317796..c8f0ad7ed9 100644
--- a/packages/svelte/CHANGELOG.md
+++ b/packages/svelte/CHANGELOG.md
@@ -1,5 +1,15 @@
 # svelte
 
+## 5.27.0
+
+### Minor Changes
+
+- feat: partially evaluate certain expressions ([#15494](https://github.com/sveltejs/svelte/pull/15494))
+
+### Patch Changes
+
+- fix: relax `:global` selector list validation ([#15762](https://github.com/sveltejs/svelte/pull/15762))
+
 ## 5.26.3
 
 ### Patch Changes
diff --git a/packages/svelte/package.json b/packages/svelte/package.json
index b8654671ec..af78d2679a 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": "5.26.3",
+  "version": "5.27.0",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {
diff --git a/packages/svelte/src/version.js b/packages/svelte/src/version.js
index 1909588146..27a39136f8 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 = '5.26.3';
+export const VERSION = '5.27.0';
 export const PUBLIC_VERSION = '5';