Howdy!

I stumbled upon problem with setup_requires and pip/poetry while using corporate PYPI mirror. As this package is used by pytest 6.0 (released 2 days ago) it can break things for many people.

Current workaround is to install setuptools-scm manually via pip, before poetry, but it still requires time to debug and fix.

More references for this problem: pytest-dev/pytest-xdist#136 pypa/setuptools#209