[BUG] stdlib test_distutils on python3.8 runs only with SETUPTOOLS_USE_DISTUTILS=stdlib

[mattip]

setuptools version

setuptools==60.0.0

Python version

Python 3.8

OS

Ubuntu 20.04

Additional environment information

No response

Description

Collecting the stdlib test_distutils.py test suite fails unless I use SETUPTOOLS_USE_DISTUTILS=stdlib with setuptools>60

Expected behavior

I can set SETUPTOOLS_USE_DISTUTILS=stdlib, but thought this should work without it?

How to Reproduce

$ sudo apt install libpython3.8-testsuite python3-venv
$ python3.8 -venv /tmp/venv_py3.8
$ /tmp/venv_py3.8/bin/python /usr/lib/python3.8/test/test_distutils.py
# tests run, 2 fail
$ /tmp/venv_py3.8/bin/python -m pip install "setuptools>59"
...
Successfully installed setuptools-60.1.0
$ /tmp/venv_py3.8/bin/python /usr/lib/python3.8/test/test_distutils.py
Traceback (most recent call last):
  File "/usr/lib/python3.8/test/test_distutils.py", line 8, in <module>
    import distutils.tests
ModuleNotFoundError: No module named 'distutils.tests'

Output

$ /tmp/venv_py3.8/bin/python /usr/lib/python3.8/test/test_distutils.py
Traceback (most recent call last):
  File "/usr/lib/python3.8/test/test_distutils.py", line 8, in <module>
    import distutils.tests
ModuleNotFoundError: No module named 'distutils.tests'

Code of Conduct

• I agree to follow the PSF Code of Conduct

[jaraco]

The way the distutils hack works, it makes Setuptools' own copy of distutils take precedence over the standard library, so causes import distutils to put sys.modules['distutils'] = <setuptools._distutils>. So it's not a big surprise to me that running the tests from the standard library against code not in the standard library will have problems.

What is something of a surprise is the error message you encountered. I don't encounter that error if I run .tox/python/bin/python -m test.test_distutils from the setuptools source.

I'm guessing that because packages.find excludes tests* and *.tests, that means that the tests get omitted on install, so that distutils.tests package simply isn't present.

My recommendation would be to continue to run tests with =stdlib or to avoid running those tests. I know some people have invested energy into ensuring that Setuptools doesn't install its tests, so it's not a mistake that the distutils tests aren't present either. And even if they were present, having them execute when running stdlib tests doesn't seem like the right or intended behavior.

Do you have any other recommendations in mind?

[frapa-az]

Hi, I just got stuck in a similar error. On python 3.8 (which is the default on ubuntu 20.04 LTS), with setuptools 60.x, I am unable to install packages in editable mode without SETUPTOOLS_USE_DISTUTILS=stdlib. If I downgrade, install normally or add SETUPTOOLS_USE_DISTUTILS=stdlib the installation works as expected.

Here a reproducible example:

setuptools_60_issue.zip

To reproduce, perform the following steps in the unpacked folder:

$ docker build . -t setuptools_60_issue
$ docker run -it setuptools_60_issue
root@cfb245293780:/#

# As expected, if the module is not installed, it fails
root@cfb245293780:/# python3 -c "import example_mod"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ModuleNotFoundError: No module named 'example_mod'

# But, it also fails when the module is installed in editable mode
# NOTE: pip reports successful install but then the module is unavailable
root@cfb245293780:/# pip install -e package/
Obtaining file:///package
Installing collected packages: setuptools-60-issue
  Running setup.py develop for setuptools-60-issue
Successfully installed setuptools-60-issue
root@cfb245293780:/# python3 -c "import example_mod"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ModuleNotFoundError: No module named 'example_mod'

If works fine with the env var or with normal install. It also works with python 3.9.

[robertschweizer]

The issue described by @frapa-az has not been fixed and persists in all setuptools versions >=60. Main issue: #3301