updating setuptools causes pip to no longer import as a module successfully

[kevinushey]

Description

After upgrading setuptools, I'm no longer able to import pip as a module within a Python REPL. This is on macOS, using Python 3.9.9 from Homebrew.

/opt/homebrew/bin/python3 -m venv /tmp/venv
/tmp/venv/bin/python -m pip install --upgrade setuptools
/tmp/venv/bin/python -c 'import pip; print(pip.__version__)'

Running this, I see:

$ /tmp/venv/bin/python -c 'import pip; print(pip.__version__)'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
  File "<frozen importlib._bootstrap>", line 982, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 925, in _find_spec
  File "/private/tmp/venv/lib/python3.9/site-packages/_distutils_hack/__init__.py", line 83, in find_spec
    return method()
  File "/private/tmp/venv/lib/python3.9/site-packages/_distutils_hack/__init__.py", line 104, in spec_for_pip
    if self.pip_imported_during_build():
  File "/private/tmp/venv/lib/python3.9/site-packages/_distutils_hack/__init__.py", line 115, in pip_imported_during_build
    return any(
  File "/private/tmp/venv/lib/python3.9/site-packages/_distutils_hack/__init__.py", line 116, in <genexpr>
    frame.f_globals['__file__'].endswith('setup.py')
KeyError: '__file__'

Expected behavior

Ideally, pip should load as a module without issue.

pip version

21.3.1

Python version

3.9.9

OS

macOS 12.1

How to Reproduce

See above.

Output

See above.

Code of Conduct

• I agree to follow the PSF Code of Conduct.

[kevinushey]

The official documentation suggests keeping these up-to-date together:

https://packaging.python.org/en/latest/tutorials/installing-packages/#ensure-pip-setuptools-and-wheel-are-up-to-date

That said, I'm not sure whether this would be considered an issue in pip or setuptools.

[pfmoore]

That _distutils_hack file isn't part of pip, so this isn't a pip issue. It looks like the file is installed by setuptools, so maybe report this to setuptools?

[pfmoore]

Actually, see pypa/setuptools#2941

[kevinushey]

Thanks! I just spotted that as well; it does indeed appear to be a setuptools issue. Sorry for the noise.

[pfmoore]

No worries, thanks for reporting it, it's good to have visibility of it in case others report it here too.