From d798dfee0d20743c0d60680bbe984f0398594c8e Mon Sep 17 00:00:00 2001
From: Simon Holthausen <simon.holthausen@vercel.com>
Date: Tue, 24 Feb 2026 22:57:38 +0100
Subject: [PATCH] fix: set server context after async transformError

This will get the tests in https://github.com/sveltejs/kit/pull/15308 green, right now they fail because page state cannot be found because context not available
---
 .changeset/gentle-emus-walk.md                |  5 +++++
 .../svelte/src/internal/server/renderer.js    |  1 +
 .../samples/async-error-boundary-3/_config.js | 16 ++++++++++++++++
 .../async-error-boundary-3/child.svelte       | 14 ++++++++++++++
 .../async-error-boundary-3/main.svelte        | 19 +++++++++++++++++++
 5 files changed, 55 insertions(+)
 create mode 100644 .changeset/gentle-emus-walk.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-error-boundary-3/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-error-boundary-3/child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-error-boundary-3/main.svelte

diff --git a/.changeset/gentle-emus-walk.md b/.changeset/gentle-emus-walk.md
new file mode 100644
index 0000000000..760b952856
--- /dev/null
+++ b/.changeset/gentle-emus-walk.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: set server context after async transformError
diff --git a/packages/svelte/src/internal/server/renderer.js b/packages/svelte/src/internal/server/renderer.js
index 9f71d53f6d..c6966090dc 100644
--- a/packages/svelte/src/internal/server/renderer.js
+++ b/packages/svelte/src/internal/server/renderer.js
@@ -293,6 +293,7 @@ export class Renderer {
 				}
 
 				child.promise = /** @type {Promise<unknown>} */ (result).then((transformed) => {
+					set_ssr_context(parent_context);
 					child.#out.push(`<!--${HYDRATION_START_FAILED}${JSON.stringify(transformed)}-->`);
 					failed_snippet(child, transformed, noop);
 					child.#out.push(BLOCK_CLOSE);
diff --git a/packages/svelte/tests/runtime-runes/samples/async-error-boundary-3/_config.js b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-3/_config.js
new file mode 100644
index 0000000000..02daf60bc6
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-3/_config.js
@@ -0,0 +1,16 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	solo: true,
+	mode: ['hydrate', 'async-server', 'client'],
+	ssrHtml: '<p>caught: error (hello)</p>',
+	transformError: () => {
+		return Promise.resolve('error');
+	},
+
+	async test({ assert, target }) {
+		await tick();
+		assert.htmlEqual(target.innerHTML, '<p>caught: error (hello)</p>');
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-error-boundary-3/child.svelte b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-3/child.svelte
new file mode 100644
index 0000000000..90d4c14cfc
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-3/child.svelte
@@ -0,0 +1,14 @@
+<script>
+	import { get } from "./main.svelte";
+
+    let { error } = $props();
+    const context = get()
+</script>
+
+{#if error}
+    <p>caught: {await error} ({context})</p>
+{:else}
+	{(() => {
+        throw 'catch me';
+    })()}
+{/if}
diff --git a/packages/svelte/tests/runtime-runes/samples/async-error-boundary-3/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-3/main.svelte
new file mode 100644
index 0000000000..a467f7500f
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-error-boundary-3/main.svelte
@@ -0,0 +1,19 @@
+<script module>
+	import { createContext } from "svelte";
+	import Child from "./child.svelte";
+
+	const [ get, set ] = createContext();
+	export {get};
+</script>
+
+<script>
+	set('hello');
+</script>
+
+<svelte:boundary>
+	{#snippet failed(error)}
+		<Child {error} />
+	{/snippet}
+
+	<Child />
+</svelte:boundary>