Vite build fails when library has React code in a ".ts" file

[milang]

Describe the bug

Vite build for our application started failing after upgrading @vitejs/plugin-react from 2.0.0 to 2.0.1.

I was able to reproduce this error in the repository https://github.com/milang/vite-issues, branch plugin-react-201. It contains acme-app generated using create-vite@3.0.2, and a simple acme-lib that represents our internal library that is causing the build to fail. Reproduction steps:

git clone https://github.com/milang/vite-issues.git
cd vite-issues
git checkout plugin-react-v201
pnpm install
pnpm run -C packages/acme-app build
# => fails with
# [vite:react-babel] C:\Users\milang\dev\vite-issues\packages\acme-lib\src\styled.ts: Support for the experimental syntax 'flow' isn't currently enabled (3:8):
# ...

Actual behaviour: Build fails
Expected behaviour: Build succeeds

Note 1

A follow-up branch plugin-react-v200 reverts @vitejs/plugin-react back to 2.0.0. Switching to this branch makes the build succeed:

# (same directory as above)
git checkout plugin-react-v200 # switch to branch with @vitejs/plugin-react@2.0.0
pnpm install
pnpm run -C packages/acme-app build
# => build succeeds

Note 2

As I was experimenting with the reproduction steps, I noticed that I can simply rename styled.ts to styled.tsx (changing the file extension), after which the build succeed. While this is a simple "fix", behaviour of version 2.0.0 was IMO much better because it worked without a rename (and rename might not be possible when dealing with a 3rd party library).

# (same directory as above)
git checkout plugin-react-v201 # switch back to branch with @vitejs/plugin-react@2.0.1
pnpm install
mv packages/acme-lib/src/styled.ts packages/acme-lib/src/styled.tsx # change extension of the problematic file
pnpm run -C packages/acme-app build
# => build succeeds

Reproduction

https://github.com/milang/vite-issues/tree/plugin-react-v201

System Info

System:
  OS: Windows 10 10.0.19044
  CPU: (8) x64 Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz
  Memory: 22.11 GB / 31.94 GB
Binaries:
  Node: 16.16.0
  npm: 8.11.0
  pnpm: 7.9.0
Browsers:
  (Not relevant)

Used Package Manager

pnpm

Logs

No response

Validations

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• The provided reproduction is a minimal reproducible example of the bug.

[caghand]

This was also reported here: vitejs/vite#6202 (comment)
As discussed there, the next version of plugin-react won't have this problem anymore.

[sapphi-red]

Closing as I confirmed the reproduction now works with plugin-react 3.0.0.
I guess this is because restoreJSX was removed by vitejs/vite#9590.