fix

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

@@ -27,7 +27,7 @@ import { destroy_effect, render_effect } from './effects.js';
 import { inspect_effects, internal_set, set_inspect_effects, source } from './sources.js';
 import { get_stack } from '../dev/tracing.js';
 import { tracing_mode_flag } from '../../flags/index.js';
-import { suspend } from '../dom/blocks/boundary.js';
+import { exit, suspend } from '../dom/blocks/boundary.js';
 
 /**
  * @template V
@@ -94,9 +94,12 @@ export function async_derived(fn) {
 	render_effect(() => {
 		const current = (promise = fn());
 
-		promise.then((v) => {
+		suspend(promise).then((v) => {
 			if (promise === current) {
-				internal_set(value, v);
+				internal_set(value, v.exit());
+
+				// TODO at the very least the naming is weird here
+				exit();
 			}
 		});
 

packages/svelte/tests/runtime-runes/samples/async-attribute/_config.js

@@ -19,11 +19,14 @@ export default test({
 	async test({ assert, target, component }) {
 		d.resolve('cool');
 		await Promise.resolve();
+		await Promise.resolve();
+		await Promise.resolve();
 		await tick();
 		assert.htmlEqual(target.innerHTML, '<p class="cool">hello</p>');
 
 		d = deferred();
 		component.promise = d.promise;
+		await tick();
 		assert.htmlEqual(target.innerHTML, '<p>pending</p>');
 
 		d.resolve('neat');