From b448a62823c8fc1884461850659f113cfd2c6bbc Mon Sep 17 00:00:00 2001
From: Simon Holthausen <simon.holthausen@vercel.com>
Date: Mon, 16 Mar 2026 21:19:25 +0100
Subject: [PATCH] fix: resume inert effects when they come from offscreen

The offscreen branch was missing the "resume inert effects" logic that was just below; it never reached that because of the early continue.

Fixes #17851
---
 .changeset/fair-hands-relate.md               |  5 +++
 .../src/internal/client/dom/blocks/each.js    |  8 +++++
 .../async-each-await-stale-rows/_config.js    | 32 +++++++++++++++++++
 .../async-each-await-stale-rows/main.svelte   | 28 ++++++++++++++++
 4 files changed, 73 insertions(+)
 create mode 100644 .changeset/fair-hands-relate.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-each-await-stale-rows/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-each-await-stale-rows/main.svelte

diff --git a/.changeset/fair-hands-relate.md b/.changeset/fair-hands-relate.md
new file mode 100644
index 0000000000..fd7b3585ad
--- /dev/null
+++ b/.changeset/fair-hands-relate.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: resume inert effects when they come from offscreen
diff --git a/packages/svelte/src/internal/client/dom/blocks/each.js b/packages/svelte/src/internal/client/dom/blocks/each.js
index b248ce5544..93c1e2f155 100644
--- a/packages/svelte/src/internal/client/dom/blocks/each.js
+++ b/packages/svelte/src/internal/client/dom/blocks/each.js
@@ -500,6 +500,14 @@ function reconcile(state, array, anchor, flags, get_key) {
 				move(effect, next, anchor);
 				prev = effect;
 
+				if ((effect.f & INERT) !== 0) {
+					resume_effect(effect);
+					if (is_animated) {
+						effect.nodes?.a?.unfix();
+						(to_animate ??= new Set()).delete(effect);
+					}
+				}
+
 				matched = [];
 				stashed = [];
 
diff --git a/packages/svelte/tests/runtime-runes/samples/async-each-await-stale-rows/_config.js b/packages/svelte/tests/runtime-runes/samples/async-each-await-stale-rows/_config.js
new file mode 100644
index 0000000000..7025e4000e
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-each-await-stale-rows/_config.js
@@ -0,0 +1,32 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		const spam = /** @type {HTMLButtonElement} */ (target.querySelector('button.spam'));
+		const resolve = /** @type {HTMLButtonElement} */ (target.querySelector('button.resolve'));
+
+		resolve.click();
+		await tick();
+
+		for (let i = 0; i < 5; i += 1) {
+			spam.click();
+			await tick();
+		}
+
+		for (let i = 0; i < 5; i += 1) {
+			resolve.click();
+			await tick();
+		}
+
+		assert.equal(target.querySelectorAll('div').length, 1);
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button class="spam">Spam</button>
+				<button class="resolve">Resolve</button>
+				<div>5</div>
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-each-await-stale-rows/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-each-await-stale-rows/main.svelte
new file mode 100644
index 0000000000..aeed4fa306
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-each-await-stale-rows/main.svelte
@@ -0,0 +1,28 @@
+<script>
+	let value = $state({ id: '0' });
+	const resolvers = [];
+
+	function wait() {
+		const promise = Promise.withResolvers();
+		resolvers.push(promise.resolve);
+		return promise.promise;
+	}
+
+	function spam() {
+		value.id = `${Number(value.id) + 1}`;
+	}
+</script>
+
+<button class="spam" onclick={spam}>Spam</button>
+<button class="resolve" onclick={() => resolvers.shift()?.()}>Resolve</button>
+
+<svelte:boundary>
+	{#each [value.id] as s (s)}
+		{await wait()}
+		<div>{s}</div>
+	{/each}
+
+	{#snippet pending()}
+		<p>pending</p>
+	{/snippet}
+</svelte:boundary>