Typescript/SWC not working when root directory name contains node_modules

[Netail]

Link to the code that reproduces this issue

https://github.com/Netail/repro-next-typescript-node_modules

To Reproduce

1. Have the root directory of your project contain node_modules (In this case the default git clone name repro-next-typescript-node_modules)
2. Install dependencies; yarn install
3. Start the dev server; yarn dev
4. Open localhost:3000 so it compiles the page
5. See errors being thrown in the console regarding not being able to parse tokens. (e.g. import type or : FC)

Current vs. Expected behavior

When the root directory contains the word node_modules, SWC fails to transpile the typescript files, while the rest seems to be working fine. I expected Typescript to be working fine, regardless of the root directory name

Provide environment information

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 10 Home    
  Available memory (MB): 32702
  Available CPU cores: 8
Binaries:
  Node: 22.11.0
  npm: 10.9.0
  Yarn: 1.22.22
  pnpm: N/A
Relevant Packages:
  next: 15.1.3 // Latest available version is detected (15.1.3).
  eslint-config-next: N/A
  react: 19.0.0
  react-dom: 19.0.0
  typescript: 5.5.4
Next.js Config:
  output: N/A

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

TypeScript, SWC

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

next dev (local), next build (local)

Additional context

I was testing another bug regarding node_modules & bundling and called the directory something with node_modules, this resulted in some "Module parse failed: Unexpected token" errors, which took me a few hours to realise it was because of the root directory name

[icyJoseph]

🤔 could you show a video of the issue happening?

https://stackblitz.com/github/Netail/repro-next-typescript-node_modules?file=README.md it works fine here, at least for me.

[Netail]

🤔 could you show a video of the issue happening?

stackblitz.com/github/Netail/repro-next-typescript-node_modules?file=README.md it works fine here, at least for me.

I assume stackblitz loads the content of a repo differently in, so the directory where the project gets downloaded in is not the same as the repository name. Or node_modules are not allowed to search outside of the directory, idk

repro-next-typescript-node_modules.-.Visual.Studio.Code.2024-12-29.22-49-11.mp4

[icyJoseph]

The node_modules directory is right there:

Could it be something with your system? you have win32, on a 64 bits platform? is that right? if you do node -p 'process.arch', does that match your OS?

[Netail]

It's not about the node_modules directory inside of the root directory. It's about the root directory name itself, which then contains the app, node_modules etc

repro-next-typescript-node_modules/ <---- This directory name
├─ node_modules/
├─ public/
│  ├─ .gitkeep
├─ app/
│  ├─ page.tsx
│  ├─ layout.tsx
│  ├─ favicon.ico
├─ .gitignore
├─ next.config.js
├─ package.json
├─ README.md
├─ tsconfig.json
├─ yarn.lock

Happens on both macos & windows 10

[icyJoseph]

Oh no, uff, so the issue is Typescript/SWC not working when root directory name contains node_modules

Alright, that's not good... let me do some quick research

[Netail]

Yes 😅, I see the confusion there. I first had something regarding the name in the title Typescript not working when directory has node_modules in it's name, but this felt a bit too long. So accidentally pruned this crucial keyword

[Netail]

Alright, that's not good... let me do some quick research

I mean it's quite an edge case, who would add node_modules in the name of their root directory in a real project? I only stumbled upon it because I was working on a different repro.

[icyJoseph]

Ok, I think I've got the error narrowed down, let me try to see if I can make a PR.

[icyJoseph]

Here ya go, #74408 - it was introduced when these improvements where made, #62005

[Netail]

Awesome, thanks :)