Inconsistent behavior of usePathname with static rendering during build

[amannn]

Link to the code that reproduces this issue

amannn/nextjs-bug-repro-usepathnamessg@c6b084d

To Reproduce

Compare the output of usePathname in development vs during the static prerender when accessing the route /test which uses a rewrite in the middleware.

Current vs. Expected behavior

usePathname seems to pick up a request-time pathname from a middleware rewrite. However, as this information is not available during a static build, usePathname will return a different value in this case. Then again, when running the app in production, usePathname will return the pathname that's displayed in the browser (i.e. after a rewrite), but only on the client side.

In the reproduction this leads to a text content mismatch, but more generally this breaks a dev/prod guarantee. I'd expect a static prerender to only be a performance optimization and not to change application logic.

I guess some unification would be necessary here.

Note that this only applies for static prerendering, if you use SSR in production then the behavior is the same as in dev.

A more real world use case where this behavior was encountered: amannn/next-intl#1568

Provide environment information

Operating System:
  Platform: darwin
  Arch: x64
  Version: Darwin Kernel Version 23.6.0: Mon Jul 29 21:13:00 PDT 2024; root:xnu-10063.141.2~1/RELEASE_X86_64
  Available memory (MB): 16384
  Available CPU cores: 12
Binaries:
  Node: 20.11.1
  npm: 10.2.4
  Yarn: 1.22.22
  pnpm: 9.14.2
Relevant Packages:
  next: 15.0.4-canary.23 // Latest available version is detected (15.0.4-canary.23).
  eslint-config-next: 15.0.4-canary.23
  react: 19.0.0-rc-380f5d67-20241113
  react-dom: 19.0.0-rc-380f5d67-20241113
  typescript: 5.6.3
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

Middleware

Which stage(s) are affected? (Select all that apply)

next dev (local), next build (local), next start (local)

Additional context

Maybe a hook like useInternalPathname() (naming TBD) could help that always reliably returns the pathname that renders in Next.js, regardless of any rewrites—essentially matching the directory structure in src/app.