"Server function info not found" when calling a server function that's *only* called on the server #8731

Which project does this relate to?

Start

Describe the bug

If you call a server function inside another server function, and that function is only ever called on the server (and never on the client), the function call will throw a Server function info not found for [ID] error. This only happens in a production build, not in development.

Complete minimal reproducer

https://codeberg.org/lynnntropy/tanstack-start-nested-serverfn-repro

Steps to Reproduce the Bug

1. Clone the reproduction repo
2. pnpm i && pnpm build && pnpm start
3. Visit http://localhost:3000
4. See the error

Expected behavior

The function call shouldn't throw an error.

Screenshots or Videos

Platform

• Start Version: 1.169.2
• OS: Linux
• Browser: Chrome
• Browser Version: 154.0.8037.92
• Bundler: Vite
• Bundler Version: 8.3.4

Additional context

This might be related to #7943.