[BUG] Vendoring of `importlib_metadata` is shadowing actual package

setuptools version

setuptools==60.9.1

Python version

Python 3.8 and Python 3.9

OS

Ubuntu 20.04

Additional environment information

No response

Description

Since setuptools started vendoring importlib_metadata it is shadowing the actual package. This means that the type of entry points are no longer the class provided by the original importlib_metadata but the vendored package instead. Example:

Expected behavior

Installing setuptools should not have its vendored library shadow the real one changing the types returned by functions of the importlib_metadata package.

How to Reproduce

1. Install setuptools>=60.9.0 in Python 3.8 or Python 3.9

Output

Behavior of setuptools==60.8

Python 3.8.10 (default, Nov 26 2021, 20:14:08) 
Type 'copyright', 'credits' or 'license' for more information
IPython 7.31.1 -- An enhanced Interactive Python. Type '?' for help.

In [1]: import setuptools

In [2]: setuptools.__version__
Out[2]: '60.8.0'

In [3]: from importlib_metadata import entry_points

In [4]: ep = entry_points().select(group='aiida.calculations', name='core.arithmetic.add')['core.arithmetic.add']

In [5]: type(ep)
Out[5]: importlib_metadata.EntryPoint

In [6]: str(ep)
Out[6]: "EntryPoint(name='core.arithmetic.add', value='aiida.calculations.arithmetic.add:ArithmeticAddCalculation', group='aiida.calculations')"

Behavior of setuptools>=60.9.0

Python 3.8.10 (default, Nov 26 2021, 20:14:08) 
Type 'copyright', 'credits' or 'license' for more information
IPython 7.31.1 -- An enhanced Interactive Python. Type '?' for help.

In [1]: import setuptools

In [2]: setuptools.__version__
Out[2]: '60.9.1'

In [3]: from importlib_metadata import entry_points

In [4]: ep = entry_points().select(group='aiida.calculations', name='core.arithmetic.add')['core.arithmetic.add']

In [5]: type(ep)
Out[5]: setuptools._vendor.importlib_metadata.EntryPoint

In [6]: str(ep)
Out[6]: "EntryPoint(name='core.arithmetic.add', value='aiida.calculations.arithmetic.add:ArithmeticAddCalculation', group='aiida.calculations')"

Note how the type of the return value of entry_points().select has changed.