(🎁) Adopt Black and isort as code formatters

[KotlinIsland]

Description

• This will resolve Format code using Black? #10996.

⚠ When merging this don't squash the commits, we need the config and the formatting kept separate.

Changes:

• add configuration to pyproject.toml
• add test dependencies
• add to tox lint
• configure flake8 to be compatible
• add commands to runtests.py
• add .git-blame-ignore-revs
• Add badges to the readme
• Configure pre-commit for black and isort

Anything else?, Oh yeah:

• format the code (:trollface:)

TODO after this is merged

• Add the pre-commit.ci app to the GitHub project configuration. (needs owner)
• add final format ref to the .git-blame-ignore-revs file ((🎁) Add black/isort git blame ignore rev #13244)

If your PR has conflicts follow these steps

1. Rebase onto the configuration commit (not the format commit).
2. Interactively rebase from the start of your branch pausing on every commit.
3. Run git checkout --theirs .; black .; isort .; git add -A; git rebase --continue
4. repeat 3 until you pass over all commits
5. Once complete rebase onto master

Alternative suggestion by @jhance

1. Rebase onto the black configuration commit. 2. Run black and commit on the top of your PR. 3. Re-parent your diff on top of the black commit (NOT a rebase). Checkout the black commit and then `git checkout .` 4. Re-create the original commits 5. Rebase onto master

[jhance]

Can you split the actual formatting to its own commit for review purposes?

[KotlinIsland]

@jhance Done!

[hmc-cs-mdrissi]

One tip, .git-blame-ignore-revs is useful when doing a large reformatting commit like this. It allows git blame to skip certain commits as otherwise git history becomes more annoying to use. Github is about to support it, https://docs.github.com/en/repositories/working-with-files/using-files/viewing-a-file#ignore-commits-in-the-blame-view (currently in beta) and git cli has supported it for a while. It effectively skips ignored commits when doing git blame.

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉

[ilevkivskyi]

I have just one comment. Please fix it and also rebase the PR (it has conflicts), and then I will merge it. It is waiting for too long.

[hauntsaninja]

(This PR always has merge conflicts, which makes it annoying to merge. If you remove the reformatting commit, I'd be happy to merge past CI and reformat with whatever is on master at the time)

[KotlinIsland]

@hauntsaninja the reformat requires manual fixup regarding type comments, I'm happy to rebase and reformat to get these changes done.

[KotlinIsland]

@ilevkivskyi @hauntsaninja LET'S GOOO!!!

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉

[KotlinIsland]

⚠️ Remember, DO NOT squash the commits when merging, we need to preserve both separately.

[KotlinIsland]

@ilevkivskyi Can you add the pre-commit.ci app to the project configuration now?

[KotlinIsland]

This: https://github.com/marketplace/pre-commit-ci

[ilevkivskyi]

I think I can't, at least I can't figure out how do this (it only allows me to install it to my personal repos). I guess only an org admin can add apps.

[hauntsaninja]

cc @JelleZijlstra who did this for python/typeshed

[KotlinIsland]

Perhaps only owners can add apps? @JukkaL

[AlexWaygood]

Thanks for persisting with this @KotlinIsland, great to see this happen! Very minor, but the "code style with black" README badge doesn't look quite right:

[KotlinIsland]

Thanks! Oops, I'll fix that next chance I get, if someone else doesn't fix it first 😁