For anyone having issues with CMD length, PIP or Xformers building in general, try PowerShellPython

[leomaxwell973]

This is a project I've focused on xformers and flash-attn specifically for windows users.
I've gone from barley possible installs for xformers to installing seamlessly over pip after finishing it.
it's mainly designed to address the cmd length issues for xformers/flash-attn but can help with pip issues and general build env issues as well or just give an alternative shell to throw at it if your errors are more general/niche.

https://github.com/leomaxwell973/PowerShellPython/

[massiveinvisible]

I've tried this and still can't get it to build. Definitely fewer path length issues, but still eventually got this one:

ninja: error: Stat(C:/Users/xxx/AppData/Local/Temp/pip-install-7u3yat1e/xformers_62be5de98d76496599de7d966daffd53/build/temp.win-amd64-cpython-310/Release/Users/xxx/AppData/Local/Temp/pip-install-7u3yat1e/xformers_62be5de98d76496599de7d966daffd53/third_party/flash-attention/csrc/flash_attn/flash_api.obj): Filename longer than 260 characters