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 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