postcss configuration in package.json is not respected in Turbopack

[BB-19]

Link to the code that reproduces this issue

https://codesandbox.io/p/devbox/turbopack-tw-bug-933t2x

To Reproduce

1. Start apps/web with npm run dev to see tailwind working fine without Turbopack.
2. Start apps/web with npm run dev-turbo to see missing styles when running with Turbopack.

Current vs. Expected behavior

Current

Tailwindcss seems to be broken in this monorepo setup when using Turbopack. No error messages are displayed but the styles are missing. Without the --turbo flag, this setup works just fine.

Expected

Tailwindcss should work fine in this monorepo when using Turbopack.

Provide environment information

Operating System:
  Platform: linux
  Arch: x64
  Version: #1 SMP PREEMPT_DYNAMIC Sun Aug  6 20:05:33 UTC 2023
  Available memory (MB): 4102
  Available CPU cores: 2
Binaries:
  Node: 20.9.0
  npm: 9.8.1
  Yarn: 1.22.19
  pnpm: 8.10.2
Relevant Packages:
  next: 14.1.2-canary.3 // Latest available version is detected (14.1.2-canary.3).
  eslint-config-next: 14.1.1
  react: 18.2.0
  react-dom: 18.2.0
  typescript: 5.3.3
Next.js Config:
  output: N/A

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

Turbopack (--turbo)

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

next dev (local)

Additional context

No response

_PACK-2657

[ForsakenHarmony]

There is a warning, but unfortunately it never gets shown to the user

The issue is that the postcss config is inside package.json which is currently not supported

[BB-19]

There is a warning, but unfortunately it never gets shown to the user

The issue is that the postcss config is inside package.json which is currently not supported

Ah that makes sense, forgot to test that. Unfortunately there is no way around it currently since the repo is ESM only and there still seems to be an issue with tailwind/postcss/nextjs, when using the postcss config outside of package.json. See #34448.

[timneutkens]

This has been fixed in #68679. Thanks for the report!

[github-actions]

This closed issue has been automatically locked because it had no new activity for 2 weeks. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.