Make format-on-save easier for Python

[nealrichardson]

I seem to be struggling with this in Positron more than I did in VS Code, though maybe I did some extra setup steps there that I don't remember now. I've enabled the "Format on save" setting, but nothing ever happens in either Python or R (I haven't tried C++ in Positron yet).

I know that Python and R packages are required to do the formatting, but I would expect either that (a) when I create a virtualenv from the command pallete, it would also install black there if that's what's needed to do formatting, or (b) it would prompt me to install black, just as it often does (or used to at least) prompt me to install ipython for jupyter, or (c) raise some message that it couldn't format on save because I have to install some package.

[jmcphers]

For R, you need to install the styler package, after which "format on save" should work. See this comment: #1407 (comment). I've filed #2251 to track the work to break that dependency.

For Python, the core Python extension we use doesn't support format on save (see https://code.visualstudio.com/docs/python/formatting). You can use black via https://open-vsx.org/extension/ms-python/black-formatter which is available via OpenVSX.

Don't disagree that this should be easier/we should bundle or help you do this.

[nealrichardson]

I wondered if there was something up with the Python extension because when I searched the settings for format on save, I was surprised that there wasn't an entry under Python that would let me choose black or something else, which I recall having in VS Code.

[petetronic]

Repurposing this as "Format on save" should work better out of the box for Python (as there are different issues for R as mentioned above).

[nealrichardson]

Repurposing this as "Format on save" should work better out of the box for Python (as there are different issues for R as mentioned above).

Sounds good. In case it's useful color, I've been working on a python project lately, and I've been tempted to switch back to VS Code so that I don't have to manually run black on my changes.

[isabelizimm]

If you download the black extension in Positron, format on save will work. Right now, black is a recommended extension for positron-python. If people ignore the "Download recommended extensions" popup (which, realistically, most everyone does), then you have to know to download it, which is a weird state to be in.

To make it easier for users, we could have black bundled in Positron.

If we wanted to go further, we could just bundle all the recommended extensions, which include isort and flake8 as well.

[nealrichardson]

Oh nice, I was not aware that there was a separate black extension (and I don't recall seeing a "Download recommended extensions" popup, but I may have brushed it off back in the beginning). I've installed it and now I'm nice and formatted 💅 , thank you!

I wouldn't complain if it were bundled with Positron.

[petetronic]

Positron Version: 2024.02.0 (Universal) build 1585 included a bundled version of the Black Formatter extension from the ms-python group at Microsoft under the MIT license.

[petetronic]

I set up the default formatter as the new Black Formatter, turned on Format on Save, and when I saved a .py file, it formatted using Black format rules.