I used flake8 setup.py -vvvv 2> flake8.txt and https://flake8.pycqa.org/en/latest/user/violations.html#selecting-violations-with-flake8 to determine which selections are default, apart from flake8's default, C4 (flake8-comprehensions) was the only other check that was turned on by default.

I'm a bit confused by this -- I thought the goal was to enable additional checks only for flake8-bugbear? If that's not possible, then I think we'll need to ignore all the ones that don't pass yet.

I outlined it here, but TL;DR: It's easier to individually add the checks to select= rather than remove them from ignore= one-by-one, the latter is more susceptible to merge conflicts, and it's easier to make git figure out the diff being "ah, just adding some lines here" rather than "oh, i need to remove this line, and this line, and this line...".

It's also simply easier to work with, and easier to observe explicitly enabled > implicitly enabled, i already created some other issues which touched on those explicitly-disabled checks, to create discussion to be able to remove them.

Edit: Just read your comment again, yes, that's the goal, but this is the first PR required for that, i isolated the changes to be small to this, and the next PR will be adding flake8-bugbear and non-complaining checks, once that one's merged, i'll add the one-by-one checks and the enabling in the config. See #9366.

I'm not too keen to merge this as I'm not a huge fan of disabling these checks (i.e. if we never finish a project to enable bugbear and new checks get added to flake8 then we'll be missing out). I think the approach should be to disable just the bugbear checks and start fixing those issues individually.