Deprecate SETUPTOOLS_USE_DISTUTILS=stdlib

[jaraco]

Soon, as Python 3.12 starts to roll out, users will be unable to use SETUPTOOLS_USE_DISTUTILS=stdlib. Moreover, Setuptools supporting this mode also adds complexity to the project and reduces the ability of distutils/setuptools to evolve to consolidate behaviors. Let's deprecate this mode.

[kiorky]

If i am correct, this will break the workaround needed on #3301 on old pythons on Debian based systems.

[jaraco]

Yes, perhaps. The deprecation wouldn't, but the subsequent removal probably would. There are different ways we could possibly ameliorate the situation:

• those environments would pin to older Setuptools (maybe by way of pip constraints?).
• extend distutils to support those environments.
• wait for those environments to drop support
• ??

I've added that bug to the project for consideration.

[kiorky]

• wait for those environments to drop support

This will lead up to 2027+5=2032 at least (ubuntu 22.04LTS end ESM support).

Maybe the simpler would be to make sure that downstream vendor patches handle the new setuptools flawlessly, even on old packaged pythons which are in the official tree (eg python38 on ubuntu 20.04 (support 'til 2030) or python37 on ubuntu18.04 (support 'til 2027) which even does not have the _distutils_system_mod.py file. I think everybody would be happy of that.

[hroncok]

I've been proactively building Fedora packages without distutils to see what breaks. Figured out some setuptools tests fail. Hence: #3636

[culler]

I don't think that Python 3.11.2 is considered old. However, I am unable to import setuptools without setting the environment variable that you want to remove. Wouldn't it be better to fix setuptools first?

This is what I am seeing:

Python 3.11.2 (v3.11.2:878ead1ac1, Feb 7 2023, 10:02:41) [Clang 13.0.0 (clang-1300.0.29.30)] on darwin
Type "help", "copyright", "credits" or "license" for more information.

import setuptools
Traceback (most recent call last):
File "", line 1, in
File "/Users/culler/Library/Python/3.11/lib/python/site-packages/setuptools/init.py", line 8, in
import _distutils_hack.override # noqa: F401
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/culler/Library/Python/3.11/lib/python/site-packages/_distutils_hack/override.py", line 1, in
import('_distutils_hack').do_override()
File "/Users/culler/Library/Python/3.11/lib/python/site-packages/_distutils_hack/init.py", line 77, in do_override
ensure_local_distutils()
File "/Users/culler/Library/Python/3.11/lib/python/site-packages/_distutils_hack/init.py", line 64, in ensure_local_distutils
assert '_distutils' in core.file, core.file
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: /Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/distutils/core.py
import os
os.environ['SETUPTOOLS_USE_DISTUTILS'] = 'stdlib'
import setuptools
setuptools.version
'67.6.0'