Redirect loop with optional path params, layout route and index route

[SashkaHavr]

Which project does this relate to?

Router

Describe the bug

I'm falling into an infinite redirect loop using the following directory structure:

├── src/
│   ├── routes/
│   │   ├── {-$locale}/
│   │   │   ├── index.tsx
│   │   │   └── route.tsx
│   │   └── `__root.tsx`

Not posting codesandbox link here beacause it breaks the browser

Your Example Website or App

https://github.com/SashkaHavr/tsrouter-optional-path-params-repro

Steps to Reproduce the Bug or Issue

1. pnpm install
2. pnpm dev
3. Visit http://localhost:3000/
4. Look at server console output

Result: "render /{-$locale}/route.tsx" is infinitelly spammed in console and page is never opened

Expected behavior

Index page with default locale is opened

Screenshots or Videos

No response

Platform

• Router / Start Version: 1.128.4/1.128.5
• OS: Windows
• Browser: Chrome
• Bundler: vite
• Bundler Version: 7.0.5

Additional context

Workaround:

1. Move beforeLoad from /src/routes/{-$locale}/route.tsx into /src/routes/{-$locale}/index.tsx
2. Delete /src/routes/{-$locale}/route.tsx

Result: Index page with default locale is opened

[KiwiKilian]

I'm experiencing the same, I think it might be introduced by #4685. Or it was there before and covered for me by the other issue.

It can be seen in this reproduction. Open the console prior to clicking "Broken Path".