bring over test from #17162

packages/svelte/tests/runtime-runes/samples/async-ignore-skipped-block/_config.js

@@ -0,0 +1,29 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		await tick();
+
+		const [a, b] = target.querySelectorAll('button');
+
+		assert.htmlEqual(target.innerHTML, `<button>a 0</button><button>b 0</button><p>hello</p>`);
+
+		a.click();
+		await tick();
+		assert.htmlEqual(target.innerHTML, `<button>a 0</button><button>b 0</button><p>hello</p>`);
+
+		a.click();
+		await tick();
+		assert.htmlEqual(target.innerHTML, `<button>a 2</button><button>b 0</button><p>hello</p>`);
+
+		a.click();
+		await tick();
+		assert.htmlEqual(target.innerHTML, `<button>a 2</button><button>b 0</button><p>hello</p>`);
+
+		// if we don't skip over the never-resolving promise in the `else` block, we will never update
+		b.click();
+		await tick();
+		assert.htmlEqual(target.innerHTML, `<button>a 3</button><button>b 1</button><p>hello</p>`);
+	}
+});

packages/svelte/tests/runtime-runes/samples/async-ignore-skipped-block/main.svelte

@@ -0,0 +1,14 @@
+<script>
+	let a = $state(0);
+	let b = $state(0);
+	let show = $state(true);
+</script>
+
+<button onclick={() => (a++, show = !show)}>a {a}</button>
+<button onclick={() => (b++, show = !show)}>b {b}</button>
+
+{#if show}
+	<p>hello</p>
+{:else}
+	{await new Promise(() => {})}
+{/if}