bug: Cannot generate static page

[DawnMD]

Provide environment information

  System:
    OS: macOS 15.0.1
    CPU: (8) arm64 Apple M2
    Memory: 89.05 MB / 16.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 20.9.0 - ~/Library/Caches/fnm_multishells/23543_1730102638399/bin/node
    npm: 10.2.5 - ~/Library/Caches/fnm_multishells/23543_1730102638399/bin/npm
    pnpm: 9.4.0 - ~/Library/Caches/fnm_multishells/23543_1730102638399/bin/pnpm

Describe the bug

Pages are not generated statically when prefetching in a page or directly in a layout. If we remove all prefetch (be it await or void) then pages are generated statically.

Its mostly an issue when fetching some data from a CMS, as prefetch all or each the data from CMS will be a good way to render page statically

Tried to use next 15's static page symbol after upgrading, there also no static page symbol is showing when prefetching at the page/layout

Reproduction repo

https://github.com/t3-oss/create-t3-app

To reproduce

1. Scaffold the app with
   • App router
   • tRPC
   • Tailwind
2. Update the build script with --debug
3. You'll get Static generation failed due to dynamic usage on /, reason: headers

Additional information

With prefetch at page level

Without prefetch

[juliusmarminge]

Isn't this correct? headers() rejects so Next knows to make the page dynamic? I think this is just an internal error that they catch, if there was an actual issue the error would show without --debug flag?

Pages are not generated statically when prefetching in a page or directly in a layout.

No, you'd need to export const dynamic = 'force-static' to force dynamic when doing dynamic stuff. If you do so the trpc procedures runs during build and the page is outputted as static:

So I'm not sure what the issue is