[WIP] Experiment with pixi for CI

[hadim]

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This is an experiment to try to understand two things: 1) whether pixi can be a faster alternative than micromamba 2) whether it's mature enough and has enough features for us (matrix testing)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (c23d273) 91.95% compared to head (1143cbd) 91.90%.
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #218      +/-   ##
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- Coverage   91.95%   91.90%   -0.06%     
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  Files          46       46              
  Lines        3843     3843              
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- Hits         3534     3532       -2     
- Misses        309      311       +2     

Flag	Coverage Δ
unittests	91.90% <ø> (-0.06%)	⬇️

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[hadim]

I will close here.

In short, pixi CI is not really faster than the current micromamba one. It's expected since micromamba is already quite fast and the current bottlenecks are things we can't control: 1) deps downloading and extracting or 2) cache downloading and extracting.

Finally, matrix CIs is possible but a bit hacky currently (see https://github.com/Quantco/polarify/blob/dcc30139873c4aa7500465e116b6f9f6194b77b3/.github/workflows/ci.yml#L19-L40). That being said, it will very soon be much easier (see prefix-dev/pixi#239).

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TLDR: I foresee a bright future for the pixi tool, but for now, it does not make sense to switch datamol to it.