ALKASJDFALSKDFJ the test passes

packages/svelte/src/internal/client/dom/operations.js

@@ -131,10 +131,10 @@ export function child(node, is_text) {
 /**
  * Don't mark this as side-effect-free, hydration needs to walk all nodes
  * @param {DocumentFragment | TemplateNode[]} fragment
- * @param {boolean} is_text
+ * @param {boolean} [is_text]
  * @returns {Node | null}
  */
-export function first_child(fragment, is_text) {
+export function first_child(fragment, is_text = false) {
 	if (!hydrating) {
 		// when not hydrating, `fragment` is a `DocumentFragment` (the result of calling `open_frag`)
 		var first = /** @type {DocumentFragment} */ (get_first_child(/** @type {Node} */ (fragment)));

packages/svelte/src/internal/client/render.js

@@ -4,6 +4,7 @@ import { DEV } from 'esm-env';
 import {
 	clear_text_content,
 	create_text,
+	first_child,
 	get_first_child,
 	get_next_sibling,
 	init_operations
@@ -28,7 +29,7 @@ import {
 import { reset_head_anchor } from './dom/blocks/svelte-head.js';
 import * as w from './warnings.js';
 import * as e from './errors.js';
-import { assign_nodes } from './dom/template.js';
+import { append, assign_nodes, comment } from './dom/template.js';
 import { is_passive_event } from '../../utils.js';
 import { COMMENT_NODE } from './constants.js';
 import { boundary } from './dom/blocks/boundary.js';
@@ -219,8 +220,8 @@ function _mount(Component, { target, anchor, props = {}, events, context, intro
 	var unmount = component_root(() => {
 		var anchor_node = anchor ?? target.appendChild(create_text());
 
-		boundary(anchor_node, {}, (anchor_node) =>
-			branch(() => {
+		branch(() => {
+			boundary(/** @type {TemplateNode} */ (anchor_node), { pending: () => {} }, (anchor_node) => {
 				if (context) {
 					push({});
 					var ctx = /** @type {ComponentContext} */ (component_context);
@@ -248,8 +249,8 @@ function _mount(Component, { target, anchor, props = {}, events, context, intro
 				if (context) {
 					pop();
 				}
-			})
-		);
+			});
+		});
 
 		return () => {
 			for (var event_name of registered_events) {

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

@@ -1,20 +0,0 @@
-import { settled } from 'svelte';
-import { ok, test } from '../../test';
-
-export default test({
-	skip_mode: ['hydrate', 'server'],
-
-	html: `
-		<p>hello</p>
-	`,
-
-	async test({ assert, target }) {
-		const p = target.querySelector('p');
-		ok(p);
-		assert.htmlEqual(p.outerHTML, '<p>Loading...</p>');
-
-		const p2 = target.querySelector('p');
-		ok(p2);
-		assert.htmlEqual(p2.outerHTML, '<p>hello</p>');
-	}
-});

packages/svelte/tests/runtime-runes/samples/async-hydrate/main.svelte

@@ -1,7 +0,0 @@
-<svelte:boundary>
-	<p>{await Promise.resolve('hello')}</p>
-
-	{#snippet pending()}
-		<p>Loading...</p>
-	{/snippet}
-</svelte:boundary>

packages/svelte/tests/runtime-runes/samples/async-no-pending/_config.js

@@ -0,0 +1,15 @@
+import { tick } from 'svelte';
+import { ok, test } from '../../test';
+
+export default test({
+	ssrHtml: '<p>hello</p>',
+
+	html: '',
+
+	async test({ assert, target }) {
+		await tick();
+		const p = target.querySelector('p');
+		ok(p);
+		assert.htmlEqual(p.outerHTML, '<p>hello</p>');
+	}
+});

packages/svelte/tests/runtime-runes/samples/async-no-pending/main.svelte

@@ -0,0 +1 @@
+<p>{await Promise.resolve('hello')}</p>