Cannot install mpi4py after latest release of setuptools: module 'setuptools._distutils.cygwinccompiler' has no attribute 'get_versions'

With the latest release of setuptools (60.1.0), I cannot install mpi4py any more.

I have initially raised this issue with setuptools, but it looks like this fails in conf/mpidistutils.py.

$ pip install -v mpi4py
Using pip 21.3.1 from .../venv-mpi4py/lib/python3.8/site-packages/pip (python 3.8)
Collecting mpi4py
  Using cached mpi4py-3.1.3.tar.gz (2.5 MB)
  Running command .../venv-mpi4py/bin/python /tmp/pip-standalone-pip-fmkquq0f/__env_pip__.zip/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-nun8azx9/overlay --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- 'setuptools >= 40.9.0' wheel
  Collecting setuptools>=40.9.0
    Using cached setuptools-60.1.0-py3-none-any.whl (952 kB)
  Collecting wheel
    Using cached wheel-0.37.1-py2.py3-none-any.whl (35 kB)
  Installing collected packages: wheel, setuptools
  Successfully installed setuptools-60.1.0 wheel-0.37.1
  Installing build dependencies ... done
  Running command .../venv-mpi4py/bin/python .../venv-mpi4py/lib/python3.8/site-packages/pip/_vendor/pep517/in_process/_in_process.py get_requires_for_build_wheel /tmp/tmputajppc5
  Traceback (most recent call last):
    File ".../venv-mpi4py/lib/python3.8/site-packages/pip/_vendor/pep517/in_process/_in_process.py", line 363, in <module>
      main()
    File ".../venv-mpi4py/lib/python3.8/site-packages/pip/_vendor/pep517/in_process/_in_process.py", line 345, in main
      json_out['return_val'] = hook(**hook_input['kwargs'])
    File ".../venv-mpi4py/lib/python3.8/site-packages/pip/_vendor/pep517/in_process/_in_process.py", line 130, in get_requires_for_build_wheel
      return hook(config_settings)
    File "/tmp/pip-build-env-nun8azx9/overlay/lib/python3.8/site-packages/setuptools/build_meta.py", line 162, in get_requires_for_build_wheel
      return self._get_build_requires(
    File "/tmp/pip-build-env-nun8azx9/overlay/lib/python3.8/site-packages/setuptools/build_meta.py", line 143, in _get_build_requires
      self.run_setup()
    File "/tmp/pip-build-env-nun8azx9/overlay/lib/python3.8/site-packages/setuptools/build_meta.py", line 158, in run_setup
      exec(compile(code, __file__, 'exec'), locals())
    File "setup.py", line 462, in <module>
      from mpidistutils import setup
    File "/tmp/pip-install-k7kbt967/mpi4py_fa187d0418384267943227507227365d/conf/mpidistutils.py", line 29, in <module>
      cygcc_get_versions = cygcc.get_versions
  AttributeError: module 'setuptools._distutils.cygwinccompiler' has no attribute 'get_versions'
  Getting requirements to build wheel ... error

So mpi4py should restrict build dependency to setuptools<60.1.0 or fix this issue. As it stands now, installing latest released mpi4py versions does not work.

[dalcinl]

@EnricoMi Many thanks for your help and followup on this issue. I added my own comments. While it is true I could make a new release with the hotfix for the issue, it is also true that setuptools would not be able to install any of the older mpi4py releases, and users may have legitimate reasons to do that. So I truly believe setuptools should provide some sort of fix, even if just adding a line def get_versions(): raise RuntimeError("no longer supported").

[dalcinl]

@EnricoMi This is a possible workaround. Could you please double-check?