don't accidentally narrow global ownership, fix has_owner method

Author: dummdidumm

packages/svelte/src/internal/client/dev/ownership.js

@@ -133,8 +133,10 @@ function add_owner_to_object(object, owner) {
 	const metadata = /** @type {import('#client').ProxyMetadata} */ (object?.[STATE_SYMBOL]);
 
 	if (metadata) {
-		// this is a state proxy, add owner directly
-		(metadata.owners ??= new Set()).add(owner);
+		// this is a state proxy, add owner directly, if not globally shared
+		if (metadata.owners !== null) {
+			metadata.owners.add(owner);
+		}
 	} else if (object && typeof object === 'object') {
 		if (object[ADD_OWNER]) {
 			// this is a class with state fields. we put this in a render effect
@@ -159,10 +161,13 @@ function add_owner_to_object(object, owner) {
  */
 function has_owner(metadata, component) {
 	if (metadata.owners === null) {
-		return metadata.parent === null ? true : has_owner(metadata.parent, component);
+		return true;
 	}
 
-	return metadata.owners.has(component);
+	return (
+		metadata.owners.has(component) ||
+		(metadata.parent !== null && has_owner(metadata.parent, component))
+	);
 }
 
 /**

packages/svelte/src/internal/client/types.d.ts

@@ -165,7 +165,7 @@ export interface ProxyMetadata<T = Record<string | symbol, any>> {
 	p: ProxyStateObject<T>;
 	/** The original target this proxy was created for */
 	t: T;
-	/** Dev-only — the components that 'own' this state, if any */
+	/** Dev-only — the components that 'own' this state, if any. `null` means no owners, i.e. everyone can mutate this state. */
 	owners: null | Set<Function>;
 	/** Dev-only — the parent metadata object */
 	parent: null | ProxyMetadata;

packages/svelte/tests/runtime-runes/samples/non-local-mutation-global/_config.js

@@ -0,0 +1,39 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+/** @type {typeof console.warn} */
+let warn;
+
+/** @type {any[]} */
+let warnings = [];
+
+export default test({
+	html: `<button>clicks: 0</button>`,
+
+	compileOptions: {
+		dev: true
+	},
+
+	before_test: () => {
+		warn = console.warn;
+
+		console.warn = (...args) => {
+			warnings.push(...args);
+		};
+	},
+
+	after_test: () => {
+		console.warn = warn;
+		warnings = [];
+	},
+
+	async test({ assert, target }) {
+		const btn = target.querySelector('button');
+		btn?.click();
+		await tick();
+
+		assert.htmlEqual(target.innerHTML, `<button>clicks: 1</button>`);
+
+		assert.deepEqual(warnings, []);
+	}
+});

packages/svelte/tests/runtime-runes/samples/non-local-mutation-global/child.svelte

@@ -0,0 +1,3 @@
+<script>
+	let { a = $bindable() } = $props();
+</script>

packages/svelte/tests/runtime-runes/samples/non-local-mutation-global/main.svelte

@@ -0,0 +1,12 @@
+<script>
+	import Child from './child.svelte';
+	import { global } from './state.svelte.js';
+	global.value.count = 0;
+</script>
+
+<!-- binding shouldn't accidentally narrow ownership when it's already global -->
+<Child bind:a={global.value} />
+
+<button onclick={() => global.value.count++}>
+	clicks: {global.value.count}
+</button>

packages/svelte/tests/runtime-runes/samples/non-local-mutation-global/state.svelte.js

@@ -0,0 +1 @@
+export const global = $state({ value: { count: 0 } });