Merge branch 'main' into svelte-custom-renderer

.changeset/modern-tables-fetch.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: resolve stale deriveds with latest value

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

@@ -232,7 +232,7 @@ export function async_derived(fn, label, location) {
 				for (const [b, d] of deferreds) {
 					deferreds.delete(b);
 					if (b === batch) break;
-					d.reject(STALE_REACTION);
+					d.resolve(value);
 				}
 
 				if (DEV && location !== undefined) {

packages/svelte/tests/runtime-runes/samples/async-stale-derived-3/_config.js

@@ -0,0 +1,29 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		await tick();
+
+		const [increment, pop] = target.querySelectorAll('button');
+
+		increment.click();
+		await tick();
+
+		increment.click();
+		await tick();
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`<button>increment</button><button>pop</button><p>0 0 0</p>`
+		);
+
+		pop.click();
+		await tick();
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`<button>increment</button><button>pop</button><p>2 2 1</p>`
+		);
+	}
+});

packages/svelte/tests/runtime-runes/samples/async-stale-derived-3/main.svelte

@@ -0,0 +1,22 @@
+<script>
+	let count = $state(0);
+	let other = $state(0);
+
+	const queue = [];
+
+	function push(v) {
+		if (v === 0) return v;
+
+		return new Promise((fulfil) => {
+			queue.push(() => fulfil(v));
+		});
+	}
+</script>
+
+<button onclick={() => {
+	if (count === 0) other++;
+	count++;
+}}>increment</button>
+<button onclick={() => queue.pop()?.()}>pop</button>
+
+<p>{await push(count)} {count} {other}</p>