[WIP][MAINT] implement walrus operator?

[Remi-Gau]

• Closes none

Changes proposed in this pull request:

• add hook to implement walrus operator
• run all pre-commit hooks

[github-actions]

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[Remi-Gau]

walrus operator is a python 3.8 feature so just adding a pre-commit hook to enforce it given that we have dropped python 3.7

Curious to see how others feel about it.

[codecov]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (6764c9e) 92.09% compared to head (78581c9) 91.88%.
Report is 15 commits behind head on main.

Files	Patch %	Lines
nilearn/datasets/func.py	50.00%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4202      +/-   ##
==========================================
- Coverage   92.09%   91.88%   -0.22%     
==========================================
  Files         144      144              
  Lines       16366    16348      -18     
  Branches     3426     3164     -262     
==========================================
- Hits        15073    15021      -52     
- Misses        754      785      +31     
- Partials      539      542       +3     

Flag	Coverage Δ
macos-latest_3.10_test_plotting	?
macos-latest_3.11_test_plotting	?
macos-latest_3.12_test_plotting	91.88% <88.88%> (-0.01%)	⬇️
macos-latest_3.8_test_plotting	?
macos-latest_3.9_test_plotting	?
ubuntu-latest_3.10_test_plotting	?
ubuntu-latest_3.11_test_plotting	?
ubuntu-latest_3.12_test_plotting	?
ubuntu-latest_3.12_test_pre	?
ubuntu-latest_3.8_test_min	?
ubuntu-latest_3.8_test_plot_min	?
ubuntu-latest_3.8_test_plotting	?
ubuntu-latest_3.9_test_plotting	?
windows-latest_3.10_test_plotting	?
windows-latest_3.11_test_plotting	?
windows-latest_3.12_test_plotting	?
windows-latest_3.8_test_plotting	?
windows-latest_3.9_test_plotting	?

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[ymzayek]

I like it but some of its effects that may not be clear makes me hesitant about enforcing it. No strong opinion though. Here's this blog post about it: https://martinheinz.dev/blog/79

[bthirion]

No strong feeling about this. We should follow what the majority of the community considers best practices.

[Remi-Gau]

this is defo not urgent so we can wait to get more feedback

[jeromedockes]

weak -1 for me. even though it's been around for a few releases I don't see the walrus operator being used that often; I wouldn't be surprised if some contributors don't know what it is; the updated code in the diff is not really better than the old one so I don't see a reason for the change.

As 3.7 support is dropped I don't mind new code using that operator when the contributor wants to use it, but I don't see the logic behind systematically enforcing its use wherever it could possibly be applied

[jeromedockes]

more generally I would really like to avoid going overboard with the precommit and linting stuff and only enforce coding style rules that actually make the codebase easier to maintain or contribute to (including for new contributors)