failing test for #13270

packages/svelte/tests/runtime-runes/samples/dynamic-attribute-and-attribute-directive-2/_config.js

@@ -0,0 +1,19 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	test({ target, logs, assert }) {
+		const div = target.querySelector('div');
+		const button = target.querySelector('button');
+
+		assert.deepEqual(logs, ['updated attribute', 'updated directive']);
+
+		assert.ok(div?.classList.contains('dark'));
+		assert.ok(div?.classList.contains('small'));
+
+		flushSync(() => button?.click());
+		assert.deepEqual(logs, ['updated attribute', 'updated directive', 'updated attribute']);
+		assert.ok(div?.classList.contains('dark'));
+		assert.ok(div?.classList.contains('big'));
+	}
+});

packages/svelte/tests/runtime-runes/samples/dynamic-attribute-and-attribute-directive-2/main.svelte

@@ -0,0 +1,16 @@
+<script>
+	let value = $state(0);
+
+	function dark(){
+		console.log('updated directive');
+		return true;
+	}
+
+	function get_class(){
+		console.log('updated attribute');
+		return value % 2 ? 'big' : 'small';
+	}
+</script>
+
+<div class:dark={dark()} class={get_class()}></div>
+<button onclick={()=> value++}>switch</button>