AttributeError: module 'setuptools.build_meta' has no attribute '__legacy__'

[pawamoy]

• I have searched the issue tracker and believe that this is not a duplicate.

Setuptools is too old on Windows + Python 3.6 in GitHub CI, resulting in the error shown in the title when installing dependencies like pytest-sugar or termcolor (not sure if they play a role in this issue or not).

Steps to reproduce

• in a GitHub workflow
• windows-latest
• python3.6
• install pytest-sugar and/or termcolor

Actual behavior

See the tracebacks during resolution and the errors at installation here: https://github.com/pawamoy/archan/runs/2657652009?check_suite_focus=true

See how this is fixed by upgrading setuptools before resolving/installing here ("Install dependencies" step): https://github.com/pawamoy/archan/runs/2657734541?check_suite_focus=true

Expected behavior

Not sure. I found this setuptools issue, linking to this pip bug. Maybe PDM has nothing to do here. Feel free to close, I mostly opened this for visibility 🙂