Merge branch 'main' into onoutroend-twice

.changeset/dull-oranges-fry.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: avoid declaration tag warning in event handlers

.changeset/tame-donkeys-jump.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: chain preprocessor sourcemaps with an empty `sources[0]` instead of dropping them

.changeset/young-doodles-beam.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: don't treat declaration tags as parts inside each blocks

packages/svelte/src/compiler/phases/2-analyze/visitors/shared/function.js

@@ -18,7 +18,9 @@ export function visit_function(node, context) {
 
 	context.next({
 		...context.state,
-		function_depth: context.state.function_depth + 1,
+		// we generally want to use scope.function_depth unless we specifically increased
+		// that in state.function_depth (e.g. a derived)
+		function_depth: Math.max(context.state.scope.function_depth, context.state.function_depth) + 1,
 		expression: null
 	});
 }

packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js

@@ -8,7 +8,7 @@ import { sanitize_template_string } from '../../../../../utils/sanitize_template
 import { regex_is_valid_identifier } from '../../../../patterns.js';
 import is_reference from 'is-reference';
 import { dev, is_ignored, locator, component_name } from '../../../../../state.js';
-import { build_getter } from '../../utils.js';
+import { build_getter, is_state_source } from '../../utils.js';
 import { ExpressionMetadata } from '../../../../nodes.js';
 
 /**
@@ -272,6 +272,10 @@ export function build_bind_this(expression, value, { state, visit }) {
 			const binding = state.scope.get(node.name);
 			if (!binding) return;
 
+			// if it is a state or a derived it means is a declaration tag...in that case we don't want to pass the
+			// value but the signal itself or assignment will break
+			if (is_state_source(binding, state.analysis) || binding.kind === 'derived') return;
+
 			for (const [owner, scope] of state.scopes) {
 				if (owner.type === 'EachBlock' && scope === binding.scope) {
 					ids.push(node);

packages/svelte/src/compiler/utils/mapped_code.js

@@ -311,6 +311,13 @@ function apply_preprocessor_sourcemap(filename, svelte_map, preprocessor_map_inp
 		typeof preprocessor_map_input === 'string'
 			? JSON.parse(preprocessor_map_input)
 			: preprocessor_map_input;
+	// A preprocessor map with a missing/empty `sources[0]` (e.g. from a MagicString transform
+	// created without a `source` option) can't be matched against `filename` during combination,
+	// which silently drops the chain instead of erroring. Normalize it to `filename` first, the
+	// same way Vite treats an empty `sources[0]` as referring to the file being transformed.
+	if (preprocessor_map.sources?.length === 1 && !preprocessor_map.sources[0]) {
+		preprocessor_map.sources = [filename];
+	}
 	const result_map = combine_sourcemaps(filename, [svelte_map, preprocessor_map]);
 	// Svelte expects a SourceMap which includes toUrl and toString. Instead of wrapping our output in a class,
 	// we just tack on the extra properties.

packages/svelte/tests/runtime-runes/samples/declaration-tags-each/_config.js

@@ -0,0 +1,10 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ target, assert }) {
+		const [btn1, btn2] = target.querySelectorAll('button');
+		flushSync(() => btn2.click());
+		assert.equal(btn1.textContent, '1');
+	}
+});

packages/svelte/tests/runtime-runes/samples/declaration-tags-each/main.svelte

@@ -0,0 +1,6 @@
+{#each Array(1)}
+	{let ref = $state()}
+	{let count = $state(0)}
+	<button onclick={()=>count++} bind:this={ref}>{count}</button>
+	<button onclick={()=>ref.click()}></button>
+{/each}

packages/svelte/tests/sourcemaps/samples/sourcemap-empty-source/_config.js

@@ -0,0 +1,29 @@
+import * as fs from 'node:fs';
+import MagicString from 'magic-string';
+import { test } from '../../test';
+
+// Simulates a bundler plugin (e.g. a Vite plugin using `magic-string`) that transforms
+// the Svelte source *before* it reaches `compile()`, and hands its own sourcemap to
+// `compileOptions.sourcemap` — the documented way to let svelte chain an upstream map
+// into its own output map. Crucially, the upstream map is generated *without* a `source`
+// option, exactly like `new MagicString(code).generateMap()` — this yields a sourcemap
+// whose `sources` is `['']`, which previously broke the chain entirely (see #18491)
+// instead of being treated as "this file", causing every mapping through it to resolve
+// to `{ source: null, line: null, column: null }`.
+const input = fs.readFileSync(new URL('./input.svelte', import.meta.url), 'utf-8');
+const src = new MagicString(input);
+src.overwrite(
+	src.original.indexOf('count * 2'),
+	src.original.indexOf('count * 2') + 'count * 2'.length,
+	'count * 2',
+	{
+		storeName: false
+	}
+);
+
+export default test({
+	compileOptions: {
+		sourcemap: src.generateMap({ hires: true })
+	},
+	client: [{ str: 'let doubled' }]
+});

packages/svelte/tests/sourcemaps/samples/sourcemap-empty-source/input.svelte

@@ -0,0 +1,6 @@
+<script>
+	let count = 0;
+	let doubled = count * 2;
+</script>
+
+<button>clicks: {count}</button>

packages/svelte/tests/validator/samples/declaration-tag-state-referenced-locally/input.svelte

@@ -7,3 +7,7 @@
 {let e = $state(0), f = e}
 
 {a}{b}{c}{d}{e}{f}
+
+<button onclick={() => {
+	console.log(a);
+}}>a</button>