[v2.11.1] Remove support for Python 3.9

[valeriupredoi]

Description

Closes #2406

AFAIK I removed all references for Python 3.9 - if you know of any others please holler back so I can replace them 🍺

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.62%. Comparing base (f9e6f46) to head (e04d666).
Report is 34 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2447   +/-   ##
=======================================
  Coverage   94.62%   94.62%           
=======================================
  Files         247      247           
  Lines       14057    14057           
=======================================
  Hits        13301    13301           
  Misses        756      756           

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[bouweandela]

I think we do not need from __future__ import annotations anymore with recent Python versions, would you like to give that a try? i.e. remove it from everywhere and then run the GitHub Actions matrix tests to see if it works?

[bouweandela]

This can also be removed:

ESMValCore/tests/unit/preprocessor/_regrid_esmpy/test_regrid_esmpy.py

Lines 384 to 386 in 07ba25c

	@pytest.mark.skipif(sys.version_info.major == 3
	and sys.version_info.minor == 9,
	reason="bug in mock.py for Python 3.9.0 and 3.9.1")

[bouweandela]

This needs an update:

ESMValCore/setup.cfg

Lines 37 to 39 in af5490f

	[mypy]
	# see mypy.readthedocs.io/en/stable/command_line.html
	python_version = 3.9

[valeriupredoi]

from future import annotations

you're right! It seems it's not needed anymore (after 3.10+), though I couldn't find an official source (yet my reasearch took no longer than 5 whole minutes 🤣 ), will do it here, and test with 3.10

[valeriupredoi]

tests/unit/preprocessor/_regrid_esmpy/test_regrid_esmpy.py

done in df2aa31

[valeriupredoi]

This needs an update:

ESMValCore/setup.cfg

Lines 37 to 39 in af5490f

	[mypy]
	# see mypy.readthedocs.io/en/stable/command_line.html
	python_version = 3.9

done in fb2411b

[valeriupredoi]

@bouweandela have a look at the flake8 barf now that we've removed from future... - F821 is indeed an undefined name in flake8 error parlance, but it's typing assignment, not variable assignment - any suggestions (before I peasantly put a # noqa there 😁 )? Related issue PyCQA/pyflakes#528 - but it doesn't seem to have a proper resolution

[bouweandela]

I tried to fix the flake8 error (it happens because the class used as a type hint is not yet defined at the point where it is used as a type hint, so in some cases you can just re-order the code and then it works), but then I tried to run the tests and found that we still need the from __future__ import annotations also where we use the bare class name (i.e. without quotes) when the used classes are imported only for type checking. In short, I think we cannot yet get rid of the from __future__ import annotations. Thanks for trying though!

[valeriupredoi]

I tried to fix the flake8 error (it happens because the class used as a type hint is not yet defined at the point where it is used as a type hint, so in some cases you can just re-order the code and then it works), but then I tried to run the tests and found that we still need the from __future__ import annotations also where we use the bare class name (i.e. without quotes) when the used classes are imported only for type checking. In short, I think we cannot yet get rid of the from __future__ import annotations. Thanks for trying though!

cheers for testing, bud! Lemme revert the commit then - easy-peasy 👍

[valeriupredoi]

OK buds, reverted those two last commites (running GA and removing from future) 🍺

[bouweandela]

Thanks! Maybe we should wait with merging until the v2.11 release is done?

[valeriupredoi]

Yep let's do that, maybe we do a rebuild when ESMValTool has the same package specs? We seeing esmpy>=8.6.0 causing some issues with resolving the env with python 3.12 at the mo at Tool, so we can wait a bit

[valeriupredoi]

I'd argue we should add a label a la "warrants/motivates a rebuild" just as we have "needs new ESMValCore release" in Tool - what do you think, bud?

[valeriupredoi]

also, excuse my verbosity today, what do you think I just remove 3.9 from the GA tests ie https://github.com/ESMValGroup/ESMValCore/actions/runs/9393366881 in a separate PR just so that release folks don't get annoyed when it comes to checking tests for the release?

[bouweandela]

They may want to run the GitHub actions on the v2.11.x branch instead of on main, as it is getting rather behind main and I would not expect the failing Python 3.9 tests on the v2.11.x branch as they were introduced in #2445 (comment), which is not included in v2.11.x.

[valeriupredoi]

sounds like what I'd do too 😁

[valeriupredoi]

@bouweandela now that @ehogan has released 2.11, would you mind if I merged this, so we get us rid of that dinosaur once and for all? 🦕

[valeriupredoi]

🦕 just about to be extinct 😁 Many thanks for the review @bouweandela 🍺