notFoundComponent defined in __root not rendered when using nitro@3.0.1-alpha.1

[theoludwig]

Which project does this relate to?

Start

Describe the bug

The notFoundComponent defined in src/routes/__root.tsx is not rendered when using nitro@3.0.1-alpha.1, but it does work if we're not using the nitro/vite plugin.

Instead of displaying the notFoundComponent, it displays:

// vite.config.ts
import { nitro } from "nitro/vite"

export default defineConfig({
  plugins: [
    nitro(),
    tanstackStart(),
    // ...
  ],
})

However, if we don't use the nitro() plugin, it works, and correctly display notFoundComponent:

// vite.config.ts
export default defineConfig({
  plugins: [
    tanstackStart(),
    // ...
  ],
})

Your Example Website or App

https://github.com/theoludwig/tanstack-repro-not-found

Steps to Reproduce the Bug or Issue

1. git clone git@github.com:theoludwig/tanstack-repro-not-found.git (project created with pnpm create tanstack-app@latest)
2. cd tanstack-repro-not-found
3. pnpm install --frozen-lockfile
4. node --run dev
5. Go http://localhost:3000/abc for example, it should shows the issue and display: Cannot GET /abc. (404 not working as expected)
6. Edit vite.config.ts to remove the nitro() plugin, refresh the page http://localhost:3000/abc, and the 404 should work correctly.

Expected behavior

The notFoundComponent defined in src/routes/__root.tsx should be used even when using the nitro v3 plugin.

Screenshots or Videos

No response

Platform

• Router / Start Version: v132
• Bundler: vite

Additional context

I don't know if this is a Nitro issue or a TanStack Router/Start issue.

[theoludwig]

cc @pi0

[banky]

Also running into the same issue, seems like nitro is handling the error instead of passing it off to the router

[pi0]

Thanks for report. Should be solved by nitrojs/nitro#3804 (you can try on nightly channel after merged before next alpha is out)

[theoludwig]

Thanks, I tested with nitro-nightly@3.0.1-20251118-175529-0316c6c6 and it works!