[Bug]: VS Code preinstall redownloads an existing icon on Windows

[dajiaohuang]

Version

System:
  OS: Microsoft Windows 10 Pro N 10.0.19045 (64-bit)
  Node: v24.14.1
  pnpm: 11.24.0
  Rstest repository: 95172d0ac0266025d9f03926ad2834a54e585c22 (main)

Details

The VS Code package's preinstall script uses the POSIX expression [ -f icon.png ] as its existence guard. pnpm runs that script through cmd.exe on Windows, where [ is not a command. The failed guard therefore reaches the curl fallback and downloads the 28,214-byte icon on every install, even when packages/vscode/icon.png already exists.

Expected behavior: an existing icon should make the preinstall step a no-op.

Actual output includes:

packages/vscode preinstall: '[' is not recognized as an internal or external command,
packages/vscode preinstall: operable program or batch file.
packages/vscode preinstall: 100 28214  100 28214

This creates an unnecessary CDN dependency for normal Windows workspace installation.

Reproduce link

rstest/packages/vscode/package.json

Line 21 in 95172d0

"preinstall": "[ -f icon.png ] || curl https://assets.rspack.rs/rstest/rstest-logo-512x512.png --output icon.png",

Reproduce Steps

1. Clone the repository on Windows and check out main.
2. Ensure packages/vscode/icon.png exists (a prior install creates it).
3. Run pnpm install --frozen-lockfile.
4. Observe that the POSIX guard fails and curl downloads the icon again.