lint: isort pre-commit & misc improvements

[casperdcl]

• consistently order imports
• add pre-commit hook
• fix minor deepsource issues
• move .flake8 root clutter to setup.cfg
• add isort to restyled
• fix or ignore CI & restyled failing for isort (maybe only an issue for this first PR adding config?)
• maybe open issue for DVC pre-commit failing for more files than hyperthreads? -> pre-commit: fails for multi-file patches #3751
• closes Restyle lint: isort pre-commit & misc improvements #3750

[skshetry]

I wanted to have this long time ago. Thanks @casperdcl 🎉

I have a question though: as this is run in virtualenv created by pre-commit, how'll this find the difference between third party and dvc?

[casperdcl]

good point @skshetry - just added a commit

[casperdcl]

not sure why travis fails... Works fine locally:

$ git clone --single-branch --branch test-isort casperdcl/dvc
Cloning into 'dvc'...
done.
$ cd dvc
dvc (test-isort)$ pre-commit run --all-files
black....................................................................Passed
isort....................................................................Passed

[skshetry]

It's because of dvc's pre-commit hook. Not sure, why it's broken. /cc @efiop

[efiop]

@skshetry Not because of dvc hook at all, you can see isort pre-commit hook failing. It reformats the code. Not sure what's up. Maybe sort version or something.

[efiop]

@casperdcl Probably should also add isort to restyled config.

[casperdcl]

It's because of dvc's pre-commit hook. Not sure, why it's broken.

No, that only fails locally on mutli-core machines where the diff touches more files than there are hyperthreads. Adding require_serial: true in the pre-commit config doesn't seem to help. :(

Not because of dvc hook at all, you can see isort pre-commit hook failing. It reformats the code. Not sure what's up.

exactly

Maybe sort version or something.

I pinned it though (to 4.3.21)

Probably should also add isort to restyled config.

will do.

[casperdcl]

well @efiop's restyled suggestion + @skshetry's note regarding third party equals #3750 - specifically, ea7c52fe192f31df4f3a273143c2d92a61024f12 - clearly not picking up the config for dvc being a first-party lib. Maybe this is because the config isn't in master yet?

[efiop]

@casperdcl Yeah, sounds likely. Could merge as is (even if it fails) and deal with it on top.

[casperdcl]

@efiop based on https://github.com/iterative/dvc/runs/650806804 this is good to merge