Symlinked app pages fail to resolve in DEV but not PRODUCTION

Verify canary release

• I verified that the issue exists in the latest Next.js canary release

Provide environment information

Operating System:
      Platform: linux
      Arch: x64
      Version: #1 SMP Fri Jan 27 02:56:13 UTC 2023
    Binaries:
      Node: 18.12.1
      npm: 9.7.1
      Yarn: 1.22.18
      pnpm: 8.6.6
    Relevant Packages:
      next: 13.4.13-canary.1
      eslint-config-next: 13.4.12
      react: 18.2.0
      react-dom: 18.2.0
      typescript: 5.1.6
    Next.js Config:
      output: N/A

Which area(s) of Next.js are affected? (leave empty if unsure)

App Router, Routing (next/router, next/navigation, next/link), SWC transpilation

Link to the code that reproduces this issue or a replay of the bug

https://github.com/cseitz/next-13.4.13-bug-symlinked-app-dir/

To Reproduce

Running next dev and visiting localhost:3000/test1 will 404 NOT FOUND.

However, running next build and next start and visiting localhost:3000/test1 will work just fine.

(Additional details in the README of my repo)

Describe the Bug

I am using a symlinked directory within my app folder. This symlink route 404's in development, but works perfectly in production.

• I have a directory, src/features/test1/app, that is symlinked into src/app/(features)/(test1)
• I symlinked this folder via ln -sr "./src/features/test1/app" "./src/app/(features)/(test1)"
• Running next dev and visiting localhost:3000/test1 will 404 NOT FOUND

Expected Behavior

When running via next dev:

• Visiting localhost:3000/test1 should render src/features/test1/app/test1/page.tsx, which is located within the symlinked folder
• That next dev mirrors the behavior of next build && next start (which is proven to support this symlink feature as it works in production)

Which browser are you using? (if relevant)

Chrome 114.0.5735.199

How are you deploying your application? (if relevant)

No response

Start with the linked reproduction repository and its README, then run next dev against /test1 and compare it with next build followed by next start. Trace how the symlinked src/app/(features)/(test1) directory resolves to src/features/test1/app/test1/page.tsx; done means development renders /test1 like production without breaking ordinary App Router routes.