python 3.10 deprecates distutils

[frozencemetery]

python-3.10 implements PEP 632 ("Deprecate distutils module"). However, our Windows build currently depends on distutils in order to monkey-patch it: https://github.com/pythongssapi/python-gssapi/blob/main/setup.py#L79-L85

@aiudirog Do you think you'd be able to look into this? We've got some time, but it'll presumably start throwing warnings on 3.10 release.

[aiudirog]

It looks like setuptools is now vendoring distutils internally as setuptools._distutils. In theory, we should just try to apply the patch to that one and fallback to the plain distutils module if it isn't available.

[jborean93]

Looking at https://github.com/pypa/setuptools/blob/a4dbe3457d89cf67ee3aa571fdb149e6eb544e88/docs/deprecated/distutils-legacy.rst and it looks like we can do something like

os.environ['SETUPTOOLS_USE_DISTUTILS'] = 'local'

# import setuptools (which will load the shim here)
import disutils

This should avoid loading in the deprecated distutils in the stdlib and use the vendored copy of distutils in setuptools. Might be a good idea to see if https://github.com/pythongssapi/python-gssapi/blob/main/setup.py#L79-L85 is still required and whether we can achieve the same thing through setuptools directly at some point in the future.

[aiudirog]

That sounds good to me. Open a PR for 3.10 support?

[jborean93]

Yea now that GHA has released 3.10 I was going to modify #263 then look into this. Because you know more about the Windows stuff it would be great if you could validate that env var does what it should on 3.10.

[aiudirog]

Just gave it a quick test on my work machine and the code you gave works. As long as the environment variable is set before setuptools is imported, it assigns setuptools._distutils as distutils in sys.modules.

[jborean93]

Thanks for confirming, will hopefully a PR up with that in there soon.

[jborean93]

#265 should solve this issue.