[Bug]: Invalid path handling with CSS, when preserveModules is true on Windows #4934
Description
Reproduction link or steps
https://github.com/stevebeauge/tsdown-css-windows-repro
pnpm build => KO (wrong CSS outpath)
What is expected?
When using output/preserveModule parameter, and CSS files, the emitted CSS files should be inside dist folder.
src/MyComponent.module.cssshould outputdist\MyComponent.module-BlAtsAg0.css(or whatever hash)
What is actually happening?
Using Windows, the output path is src\MyComponent.module-BlAtsAg0.css (inside the src folder).
Full console output:
pnpm build ─╯
> @repro/sharedui@1.0.0 build D:\code\repro\tsdown-css-windows-repro
> rolldown -c
<DIR>/D:\code\repro\tsdown-css-windows-repro\src\MyComponent.module-Cbibx9P8.css asset │ size: 0.09 kB
<DIR>/src/index.js chunk │ size: 0.07 kB
<DIR>/src/MyComponent.module.js chunk │ size: 0.14 kB
<DIR>/node_modules/.pnpm/react@19.1.0/node_modules/react/index.js chunk │ size: 0.47 kB
<DIR>/src/MyComponent.js chunk │ size: 0.53 kB
<DIR>/node_modules/.pnpm/react@19.1.0/node_modules/react/jsx-runtime.js chunk │ size: 0.54 kB
<DIR>/_virtual/rolldown_runtime.js chunk │ size: 1.16 kB
<DIR>/node_modules/.pnpm/react@19.1.0/node_modules/react/cjs/react-jsx-runtime.development.js chunk │ size: 10.28 kB
<DIR>/node_modules/.pnpm/react@19.1.0/node_modules/react/cjs/react.development.js chunk │ size: 36.11 kB
✔ Finished in 20.44 ms
System Info
System:
OS: Windows 11 10.0.26100
CPU: (22) x64 Intel(R) Core(TM) Ultra 7 155H
Memory: 6.74 GB / 31.46 GB
Binaries:
Node: 22.14.0 - C:\Program Files\nodejs\node.EXE
npm: 11.1.0 - C:\Program Files\nodejs\npm.CMD
pnpm: 10.12.1 - ~\AppData\Roaming\npm\pnpm.CMD
Browsers:
Edge: Chromium (136.0.3240.50)
npmPackages:
rolldown: 1.0.0-beta.15 => 1.0.0-beta.15Any additional comments?
Seems there's something missing in path normalization
Originally posted as tsdown issue rolldown/tsdown#319