Use black to automatically format our code

[daviddavis]

[noissue]

A couple notes. You can integrate black with version control:

https://github.com/python/black#version-control-integration

Or your IDE:

https://black.readthedocs.io/en/stable/editor_integration.html

Here is django's accepted proposal for black adoption:

https://github.com/django/deps/blob/master/accepted/0008-black.rst

[pep8speaks]

Hello @daviddavis! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2019-06-04 11:54:49 UTC

[daviddavis]

There's a conflict here between black and flake8-docstrings. Black adds this line due to the nested function ("Black won’t insert empty lines after function docstrings unless that empty line is required due to an inner function starting immediately after") while flake8-docstrings enforces a rule that there should be no blank line after docstrings (D202).

[daviddavis]

I am ignoring D202 for now until PyCQA/pydocstyle#361 (comment) is addressed.

[nixocio]

That is a really good change.

[goosemania]

Double quotes noise makes me sad :(
It turns out there was a huge flame about it psf/black#118 but the resolution was only enable/disable string normalization.

[daviddavis]

@goosemania agreed. I'm pretty indifferent to the use of single vs double but it does create a lot of noise.

[ipanova]

to me, this is more readable than what black is doing.

[rochacbruno]

In my opinion Black is making more readable (both Human and Machine readable)

Black could do better if instead of inline it did one argument by line with ending comma

packages = await RpmFirstStage.parse_repodata(
    primary_xml_path, 
    filelists_xml_path, 
    other_xml_path,
)

This style makes easier to run find-replace tools and also easier to analyse code in reviews.

[daviddavis]

I agree. It seems like it should either be one line (if it fits) or multiple lines. black does appear though to follow @rochacbruno's example if the arguments don't fit on a single line.

[gmbnomis]

This should be black --check --diff . || exit 1 (without --check black just outputs a diff without setting an error code when reformatting is required)

[daviddavis]

This PR is stale. Will open a new PR using plugin_template.