Use mypy and ruff from pixi environment

[bouweandela]

Description

Use mypy and ruff from the pixi environment instead of installing them with pre-commit.

Pros

• More accurate mypy checks because all dependencies are installed
• Manage only one environment (pixi) instead of two (pixi and pre-commit)
• No unexpected test breaking because pre-commit does not use lock files for its environments as in Tests failing - github actions pre-commit, mypy - error: "TypeAliasType" not callable #3117
• mypy and ruff can be used without pre-commit. Useful if you want to run these tools with additional options, e.g. ruff check --fix --unsafe-fixes

Cons

• Does not work with pre-commit.ci
• Runs slower on HPC, I suspect this is because mypy is accessing more files

We could decide to move away from pre-commit.ci and instead just run the pre-commit hooks on CircleCI as part of the test suite. That would also have the advantage that it has one less CI service, so easier to understand for new contributors.

Link to documentation: https://esmvaltool--3124.org.readthedocs.build/projects/ESMValCore/en/3124/contributing.html#code-quality

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.40%. Comparing base (583dcb7) to head (e571dcf).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3124      +/-   ##
==========================================
- Coverage   96.40%   96.40%   -0.01%     
==========================================
  Files         280      280              
  Lines       16248    16250       +2     
==========================================
+ Hits        15664    15665       +1     
- Misses        584      585       +1     

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[valeriupredoi]

thanks bud - a very welcome approach indeed! Approving preemptively (don't pull a Klaus on me since I approve drafts 😆 ) since I'll be away most next week

[valeriupredoi]

gotta be a solution to have pre-commit.ci work - let me dig around for a bit tomorrow

[valeriupredoi]

hey @bouweandela we has pixi in the pre-commit CI environment! Unfortunately that pixi is newer than the pixi we have in the box, so it says we should pixi migrate - I'll leave it to you if you want to accept this solution, or to revert to the non-pixi in CI env way. It took me a while to get to this, the pre-commit CI funcs are not nicely documented, but I think we have a good workaround now 🍺 Enjoy your holidays 🏖️