From 0ffd1fcb4493c4004c5226bc38abd687959dc083 Mon Sep 17 00:00:00 2001
From: paoloricciuti <ricciutipaolo@gmail.com>
Date: Fri, 18 Jul 2025 09:19:57 +0200
Subject: [PATCH] fix: keep effect in the graph if it has an abort controller

---
 .changeset/four-kings-drum.md                        |  5 +++++
 .../svelte/src/internal/client/reactivity/batch.js   |  4 +++-
 .../dependencyless-abort-signal/Component.svelte     |  8 ++++++++
 .../samples/dependencyless-abort-signal/_config.js   | 12 ++++++++++++
 .../samples/dependencyless-abort-signal/main.svelte  | 10 ++++++++++
 5 files changed, 38 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/four-kings-drum.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/dependencyless-abort-signal/Component.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/dependencyless-abort-signal/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/dependencyless-abort-signal/main.svelte

diff --git a/.changeset/four-kings-drum.md b/.changeset/four-kings-drum.md
new file mode 100644
index 0000000000..8c7343145e
--- /dev/null
+++ b/.changeset/four-kings-drum.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: keep effect in the graph if it has an abort controller
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index cdce971b18..ed82af94ed 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -532,7 +532,9 @@ function flush_queued_effects(effects) {
 				// here (rather than in `update_effect`) allows us to skip the work for
 				// immediate effects.
 				if (effect.deps === null && effect.first === null && effect.nodes_start === null) {
-					if (effect.teardown === null) {
+					// if there's no teardown or abort controller we completely unlink
+					// the effect from the graph
+					if (effect.teardown === null && effect.ac === null) {
 						// remove this effect from the graph
 						unlink_effect(effect);
 					} else {
diff --git a/packages/svelte/tests/runtime-runes/samples/dependencyless-abort-signal/Component.svelte b/packages/svelte/tests/runtime-runes/samples/dependencyless-abort-signal/Component.svelte
new file mode 100644
index 0000000000..b184e0e9b3
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/dependencyless-abort-signal/Component.svelte
@@ -0,0 +1,8 @@
+<script>
+	import { getAbortSignal } from 'svelte';
+
+	$effect(() => {
+		const signal = getAbortSignal()
+		signal.addEventListener('abort', () => console.log('abort'))
+	})
+</script>
\ No newline at end of file
diff --git a/packages/svelte/tests/runtime-runes/samples/dependencyless-abort-signal/_config.js b/packages/svelte/tests/runtime-runes/samples/dependencyless-abort-signal/_config.js
new file mode 100644
index 0000000000..6eb4b06712
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/dependencyless-abort-signal/_config.js
@@ -0,0 +1,12 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target, logs }) {
+		const btn = target.querySelector('button');
+		flushSync(() => {
+			btn?.click();
+		});
+		assert.deepEqual(logs, ['abort']);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/dependencyless-abort-signal/main.svelte b/packages/svelte/tests/runtime-runes/samples/dependencyless-abort-signal/main.svelte
new file mode 100644
index 0000000000..99ea3fabb4
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/dependencyless-abort-signal/main.svelte
@@ -0,0 +1,10 @@
+<script>
+	import Component from './Component.svelte'
+
+	let show = $state(true)
+</script>
+
+<button onclick={() => (show = !show)}>click</button>
+{#if show}
+	<Component />
+{/if}