Turbopack fails to pack css.modules with utf8-bom encoding

[Martinii89]

Link to the code that reproduces this issue

https://github.com/Martinii89/nextjs-turbo-bom-bug

To Reproduce

1. Start the application in dev mode using the --turbo option
2. The one page uses two identical css classes from two different css module files. One is encoded with utf8. The other with utf8-bom
3. Only the css module with utf8 encoding is applied correctly
   

Screenshot of the css styles in the devtools of chrome shows a error on one of the styles

Current vs. Expected behavior

Expected behaviour is that the css modules with utf8-bom encoding does not fail to apply. Currently the first selector will become invalid when utf8-bom is used.

Provide environment information

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 11 Home
  Available memory (MB): 16222
  Available CPU cores: 12
Binaries:
  Node: 20.13.1
  npm: N/A
  Yarn: N/A
  pnpm: N/A
Relevant Packages:
  next: 15.0.3-canary.4 // Latest available version is detected (15.0.3-canary.4).
  eslint-config-next: N/A
  react: 19.0.0-rc-7c8e5e7a-20241101
  react-dom: 19.0.0-rc-7c8e5e7a-20241101
  typescript: 5.3.3
Next.js Config:
  output: N/A

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

Turbopack

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

next dev (local)

Additional context

No response