Windows Support

[jsirois]

This tracks the second major effort at bringing Windows support to Pex - the 1st being in 2022. Notes will go here, issues may be broken out for actual issues.

The prior attempt branch is here: https://github.com/jsirois/pex/tree/Windows/wip

The big change from the 1st effort will be to do this incrementally with a dedicated red CI shard that has diagnostics to quantify the redness. Hopefully watching the redness go from ~100% to 0% will be the difference that helps get this over the line.

[jsirois]

Since Python 3.9 is now the current last supported release from CPython (see: https://devguide.python.org/versions/#python-release-cycle), I'll be starting there.

[jsirois]

Known major issues:

• \r\n vs \n
• \ vs / in paths
• Lib and Scripts vs lib and bin / general differences in venv layout.
• .exe and PATHEXT for executable & script file names
• console scripts need to be a binary - stub system
• ~260 char path length limit Windows path length limitations - gracefully handle ~260 char limit when present, #2660: You can exceed with a registry edit (requires Admin) and an exe with a manifest enabling (Python exes have this manifest). This is available to Windows 10+ from August 2, 2016 on in the 1607 "Redstone 1" release. See:
  • https://learn.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation?tabs=registry#enable-long-paths-in-windows-10-version-1607-and-later
  • https://en.wikipedia.org/wiki/Windows_10,_version_1607
• symlink support Windows missing symlink support - gracefully degrade to hardlink or copy #2659: This is available in Windows 10+ but must be enabled (requires Admin)
• Python exe discovery: instead of just PATH, need to consult py --list since some Pythons will only be knowable from registry entries. See: https://docs.python.org/3/using/windows.html#python-launcher-for-windows
• pyenv -> pyenv-win
• os.path.relpath and other operations vs. differing drives. Many tests already fail with this, but also noted by a hopeful bystander here: Running pex on GHA runner "windows-latest" fails #2774