[BUG] Setuptools overriding standard lib `importlib.metadata.PathDistribution`

setuptools version

60.9.3

Python version

python 3.9

OS

macOS

Additional environment information

❯ pip list
Package    Version
---------- -------
pip        22.0.4
setuptools 60.9.3
wheel      0.37.1

Description

this seems similar to https://github.com/pypa/setuptools/issues/3102, but issue was closed by #3108, without activity since then, and I still seeing this issue in the latest release.

importing setuptools overrides/removes the behavior and return type of of the standard library importlib.metadata.distribution() function:

Expected behavior

importing setuptools doesn’t supersede/remove the distribution finder from standard library importlib

How to Reproduce

1. import setuptools
2. call importlib.metadata.distribution()

Output

>>> from importlib import metadata
>>> metadata.distribution('pip')  # returns the expected type
<importlib.metadata.PathDistribution object at 0x101665910>
>>> import sys
>>> [getattr(finder, 'find_distributions', None) for finder in sys.meta_path]
[None, None, None, <bound method PathFinder.find_distributions of <class '_frozen_importlib_external.PathFinder'>>]

# importing setuptools changes the type of object returned by metadata.distribution
# and removes the _frozen_importlib_external.PathFinder from 
# the list of finders used by `metadata.Distribution.discover`
>>> import setuptools
>>> metadata.distribution('pip')
<setuptools._vendor.importlib_metadata.PathDistribution object at 0x102253070>
>>> [getattr(finder, 'find_distributions', None) for finder in sys.meta_path]
[None, None, None, None, None, None, <bound method MetadataPathFinder.find_distributions of <setuptools._vendor.importlib_metadata.MetadataPathFinder object at 0x101fdad00>>]

# note:
>>> import importlib_metadata
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'importlib_metadata'

[abravalheri]

I think it would be nice to avoid breaking the users’ expectations like it is happening right now, but since this workaround comes directly from importlib_metadata, there might be very little we can do in setuptools 😓

This workaround also seems necessary for importlib_metadata to work properly.

[tlambert03]

I think the best here is to do a structural check, since setuptools is not the only dependency that can break your plugin architecture.

I agree. thanks for having a look. If you feel like this is just how it’s going to be, I can close this issue (but feel free to re-open if you think there’s anything actionable here on your end)