merge main, add a test

sveltejs · Rich-Harris · May 28, 2025 · May 20, 2025 · May 24, 2025 · May 25, 2025
commit d5d9593940898f6b99e3783bf89e7434b4eea809
diff --git a/packages/svelte/src/internal/client/dom/elements/attachments.js b/packages/svelte/src/internal/client/dom/elements/attachments.js
@@ -10,8 +10,8 @@ import { block, branch, effect, destroy_effect } from '../../reactivity/effects.
  * @param {() => (node: Element) => void} get_fn
  */
 export function attach(node, get_fn) {
-	return effect(() => {
-		const fn = get_fn();
+	/** @type {false | undefined | ((node: Element) => void)} */
+	var fn = undefined;
 
 	/** @type {Effect | null} */
 	var e;

diff --git a/packages/svelte/tests/runtime-runes/samples/attachment-spread-stable/Component.svelte b/packages/svelte/tests/runtime-runes/samples/attachment-spread-stable/Component.svelte
@@ -0,0 +1,5 @@
+<script>
+	let props = $props();
+</script>
+
+<p {...props}>hello</p>
diff --git a/packages/svelte/tests/runtime-runes/samples/attachment-spread-stable/_config.js b/packages/svelte/tests/runtime-runes/samples/attachment-spread-stable/_config.js
@@ -0,0 +1,16 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	test({ assert, target, logs }) {
+		assert.deepEqual(logs, ['up']);
+
+		const button = target.querySelector('button');
+
+		flushSync(() => button?.click());
+		assert.deepEqual(logs, ['up']);
+
+		flushSync(() => button?.click());
+		assert.deepEqual(logs, ['up', 'down']);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/attachment-spread-stable/main.svelte b/packages/svelte/tests/runtime-runes/samples/attachment-spread-stable/main.svelte
@@ -0,0 +1,17 @@
+<script>
+	import Component from './Component.svelte';
+
+	let count = $state(0);
+</script>
+
+<button onclick={() => count++}>{count}</button>
+
+{#if count < 2}
+	<Component
+		data-count={count}
+		{@attach () => {
+			console.log('up');
+			return () => console.log('down');
+		}}
+	/>
+{/if}