Support for formatting tool "black"

[ocavue]

This issue is an enhancement request

black is a formatting tool, which has 1200 stars since 8 days ago when the first commit was pushed. It will not be long before black become a popular tool like yapf and autopep8. I think that will be great if vscode-python supports it.

[brettcannon]

Due note that https://marketplace.visualstudio.com/items?itemName=joslarson.black-vscode already exists for VS Code. But we will consider adding direct integration if Black's popularity continues to grow as it currently is.

[Kos]

I'm with OP here - Black's quick growth is extremely promising.

Moreover, since this extension already supports choosing a formatter (autopep8 / yapf), I'd much rather see Black as an alternative directly here than as a secondary extension, following the 'batteries included' spirit of this extension and VSCode in general.

[Kos]

I had a look at the code, looks like the major obstacle is that Black defaults to editing the file in-place and has (currently) no support for emitting diffs (like autopep8 or yapf). It does allow formatting stdin to stdout, but I understand that's less optimal because it makes it impractical to format a range and inconvenient if formatting takes a long time? (A diff can usually be applied even if the user did some edits after formatting was triggered).

So the options look like either:
a. implement formatting with current CLI in a sub optimal way (whole file at once without diffs) and see what happens,
b. implement --diff and --lines in black, or on top of black, and then resume

Thoughts?

[ivlevdenis]

@brettcannon black is better and more beautiful formats :)

[brettcannon]

Please leave a 👍 on the first comment for this issue to vote for this feature to help us prioritize our future work. Individual comments about support won't count as we sort on reactions when considering our work log.

[brettcannon]

After discussing this we have agreed that we would happily look at anyone's PR to implement this, but at the moment we have other stuff taking up our time so we can't do this ourselves.

[jarshwah]

I began a change about a week ago seeing what would be necessary. I ran into the lack of --diff option as well. Further, I kept crashing the plugin because I have no idea what I'm doing.

I've opened a PR just incase someone wants to pick up where I left off, as I'm not going to have time in the next few weeks.

#1234

I would recommend that someone also reaches out to the black project to implement diffing, as both pep8 and yapf support.