Add support for Python 3.11 and test 3.12-dev

[hugovk]

Problem

Python 3.11 was released on 2022-10-24 🚀

We should test it and declare support via the Trove classifier.

Solution

Add to tox.ini for local and CI testing, add to GitHub Actions for CI, and add the Trove classifier to declare support.

Also bump GitHub Actions and add colour to CI logs for readability.

Commandments

• Write PEP8 compliant code.
• Cover it with tests.
• Update CHANGES.rst file to describe the changes, and quote according issue with GH-<issue_number>.
• Pay attention to backward compatibility, or if it breaks it, explain why.
• Update documentation (if relevant).

[codecov]

Codecov Report

Merging #545 (cb292c2) into master (3dc511c) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #545   +/-   ##
=======================================
  Coverage   95.12%   95.12%           
=======================================
  Files           6        6           
  Lines         820      820           
=======================================
  Hits          780      780           
  Misses         40       40           

Impacted Files	Coverage Δ
model_utils/__init__.py	100.00% <100.00%> (ø)

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[foarsitter]

Is 3.12-dev allowed to fail? Otherwise it looks good to me.

Needless to say it would be easier that the PR only adds the changes the title says.

[hugovk]

Is 3.12-dev allowed to fail? Otherwise it looks good to me.

No, it can also fail the build. I think that's fine: 3.12 is almost in beta and should be pretty stable.

• If there's a failure, it's good to know about it sooner rather than later, so we can fix it here and be ready for the 3.12 release, and also not to block people who depend on django-model-util for their own prep.

• If it's not a quick fix, it's easy to temporarily skip 3.12-dev in the build.

• If it's a problem in CPython itself, even better, we can report upstream and get it fixed for everyone before the full release!

Needless to say it would be easier that the PR only adds the changes the title says.

I've changed the title to also say we're testing 3.12-dev here, or can also split it out to another PR if you prefer.

[foarsitter]

What you describe in point three is a good one.

[foarsitter]

@hugovk forgot about this PR but found it again wondering why there was no 3.11 in the matrix. Resolved the conflict and I think we should merge It even 3.12 is failing. Agree?

[hugovk]

Aha! Good to see a 3.12 failure, it's a valid failure showing there's something to fix in django-model-util (this is bullet point 1 above :)

    File "/home/runner/work/django-model-utils/django-model-utils/model_utils/__init__.py", line 1, in <module>
      from pkg_resources import DistributionNotFound, get_distribution
  ModuleNotFoundError: No module named 'pkg_resources'

https://docs.python.org/3.12/whatsnew/3.12.html#removed says:

easy_install, pkg_resources, setuptools and distutils are no longer provided by default in environments created with venv or bootstrapped with ensurepip, since they are part of the setuptools package. For projects relying on these at runtime, the setuptools project should be declared as a dependency and installed separately (typically, using pip).

I've pushed a commit to also install setuptools when we're on 3.12 or higher.

---

Alternatively, we're using pkg_resources to get the distribution version. Instead we can use importlib.metadata from the stdlib from 3.8+ (and a backport for 3.7), like this:

try:
    # Python 3.8+
    import importlib.metadata as importlib_metadata
except ImportError:
    # Python 3.7 and lower
    import importlib_metadata
import importlib.metadata

__version__ = importlib.metadata.version(__name__)

Or, we're in luck, Python 3.7 is end-of-life this month (https://devguide.python.org/versions/) so we could drop that backport and simplify it to:

import importlib.metadata
__version__ = importlib.metadata.version(__name__)

That would be my recommendation. What do you think?

[foarsitter]

Thanks for providing an extensive explanation about the issue, couldn't find an easy solution myself.

Using importlib is a more future proof approach I suppose so has my preferences.

Do you want to update the pull-request or merge this and use importlib when 3.7 is EOL?

[hugovk]

I'll update this PR. Do you want to wait until the official EOL (2023-06-27) or are we close enough already? Many projects have already started dropping it.

[foarsitter]

We are close enough if you ask me. 3.7 users won't miss any new features or something so can stick to 4.3.1.

[foarsitter]

Removing 3.7 here and we can merge

[hugovk]

Removed!

[hugovk]

I need to upgrade Read the Docs to use a new Python version than 3.7. Coming up!

[hugovk]

Ready!

[foarsitter]

Since this PR contains a lot of different changes squashing doesn't seem right, thoughts?

[hugovk]

Either way is fine for me, I usually don't worry too much it :)

[foarsitter]

That suits me well, reading git history still isn't something I do for leisure.

Thanks for your contribution!

[blag]

Can we get a release with this change? The current available version, 4.3.1, has an issue on the latest Pythons.