From 5d0c3c161449a751048e019b55dddfdfffd8e5ab Mon Sep 17 00:00:00 2001
From: Alem Tuzlak <t.zlak@hotmail.com>
Date: Thu, 17 Sep 2026 19:32:45 +0200
Subject: [PATCH] fix: run Nitro in-process in Start WebContainers

---
 src/utils/example-webcontainer-start.ts  | 3 +++
 tests/example-webcontainer-start.test.ts | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/src/utils/example-webcontainer-start.ts b/src/utils/example-webcontainer-start.ts
index 503b10efe..f2edf5987 100644
--- a/src/utils/example-webcontainer-start.ts
+++ b/src/utils/example-webcontainer-start.ts
@@ -104,6 +104,8 @@ export function getWebContainerStartEnv(runtime: ExampleRuntime) {
 
   if (runtime.compatibility === tanStackStartAsyncContextCompatibility) {
     env.NAPI_RS_NATIVE_LIBRARY_PATH = '@rolldown/binding-wasm32-wasi'
+    // Nitro's default node-worker never finishes loading in WebContainer.
+    env.NITRO_DEV_RUNNER = 'self'
   }
 
   return env
@@ -152,6 +154,7 @@ export default defineConfig(async (configEnv) => {
     plugins: [tanStackStartAsyncContextPlugin()],
     resolve: { noExternal },
     ssr: { noExternal },
+    nitro: { devServer: { runner: 'self' } },
   })
 })
 `
diff --git a/tests/example-webcontainer-start.test.ts b/tests/example-webcontainer-start.test.ts
index e88cdf889..0a683da7f 100644
--- a/tests/example-webcontainer-start.test.ts
+++ b/tests/example-webcontainer-start.test.ts
@@ -49,6 +49,7 @@ describe('TanStack Start WebContainer compatibility', () => {
     assert.deepEqual(getWebContainerStartEnv(startRuntime), {
       __VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS: '.webcontainer-api.io',
       NAPI_RS_NATIVE_LIBRARY_PATH: '@rolldown/binding-wasm32-wasi',
+      NITRO_DEV_RUNNER: 'self',
     })
     assert.deepEqual(
       getWebContainerStartEnv({
@@ -85,6 +86,10 @@ describe('TanStack Start WebContainer compatibility', () => {
       files[tanStackStartViteConfigPath] ?? '',
       /"@tanstack\/start\*\*"/,
     )
+    assert.match(
+      files[tanStackStartViteConfigPath] ?? '',
+      /nitro: \{ devServer: \{ runner: 'self' \} \}/,
+    )
     assert.equal(
       files['/.tanstack/async-context-plugin.mjs'],
       tanStackStartAsyncContextPluginSource,