Black: Configuration of one-per-line import splitting?

[richardARPANET]

Currently if there is an import line which is too long:

from my_app.something.blah import remove_weekends, get_daily_shape, another_import

Imports will be updated to be one per line. Not everyone wants this as it takes up vertical screen space adds more scrolling.

from my_app.something.blah import (
    remove_weekends,
    get_daily_shape,
    another_import,
)

Can we get a configuration option to update imports to take advantage of available space on each line? For example:

from my_app.something.blah import (
    remove_weekends, get_daily_shape, another_import,
)

[ambv]

The current behavior is designed with two things in mind:

• you can can reliably use isort (when configured with multiline mode 3 and trailing commas)
• you can use git blame to easily see who added an import.

Black isn't configurable so far and I would like to avoid it.

[gaborbernat]

@ambv the problem with this which I find is that it's not consistent. I mean adding another import may totally reformat the imports (and make 1 line, 12). Also there's a workaround to this:

from my_app.something.blah import remove_weekends, get_daily_shape
from my_app.something.blah import another_import

Now this will not be wrapped. I think isort can be made to work without this artificial long read. The git blame is long, but at the end of day I personally prefer four long lines of import with occasional merge conflicts, over 30 lines of import and no conflicts. Black not being configurable I can see the value in it. My question is that if it's worth the price of tons and tons of import lines for a nice git blame or not?

[ambv]

@gaborbernat, originally I also had the second step of moving the imports like this first:

from my_app.something.blah import (
  remove_weekends, get_daily_shape, ...
)

Only if that line didn't fit I would explode entirely. The problem with that was that it was incompatible with isort and I don't want to implement import sorting myself if I can help it. I tried contacting the author of isort but without luck. Since quite a few people reported the problem, I decided to just do exactly what "mode 3" does in isort so the two tools can co-exist.

[richardARPANET]

With the latest version of isort this works fine.

From:

from fdlkjfdlfldskjffkdjfdlksjflkd import fdfdfdsf, fdlkfjdsl, fdsfdsfdsfkjehkfhefekfh, fdsfdsfsd, fdskjflds,fefhekfhekfhehf, fkdjfdslkfj, fkjehfkjehfkjehkjfhekfhek, fsjflj,lkfjdflkjsffdsdfdsf

To:

from fdlkjfdlfldskjffkdjfdlksjflkd import (
    fdfdfdsf, fdlkfjdsl, fdsfdsfdsfkjehkfhefekfh, fdsfdsfsd, fdskjflds,
    fefhekfhekfhehf, fkdjfdslkfj, fkjehfkjehfkjehkjfhekfhek, fsjflj,
    lkfjdflkjsffdsdfdsf
)

With the following .isort.cfg

[settings]
line_length=79
indent='    '
multi_line_output=5

I suggest black uses this as it's a superior output.

[ambv]

It's not superior. git blame lines can't tell who added a specific import and it's inconsistent with how Black is splitting lines in any other situation.

Pro-tip: if you pipe Black's output to isort you can keep any import sorting option you want.

[richardARPANET]

It actually is. For the reasons I stated clearly above. Don't worry however, I'll simply fork the project.

[ambv]

Good luck!

[jleclanche]

@ambv I think whether it's superior output or not is kind of missing the point. isort is a popular tool and black should try to play better with it. Not necessarily introduce 10 different ways of handling import sorting/reordering, but giving the user an option to not touch import statements at all.

[rwhitt2049]

Hold the line @ambv! The less configuration the better.

[jleclanche]

@rwhitt2049 You need to step back and try to understand why "less configuration" is a good philosophy.

The goal to avoid bikeshedding is very noble. Utilities like pylint/tslint are horrible because they require tons of configuration to even work in the first place, and then have switches and toggles for what end up being absurd features.

I already told Łukasz in a separate channel how much I respect Black's resistance to configuration, but it's very important to keep in mind when it actually achieves something versus not. And tooling compatibility is a pretty important thing.

There's precedent in prettier accepting an extra configuration switch (parentheses around single lambda arguments) to play nicely with a default setting of tslint. Prettier has a very similar philosophy as Black, the less config the better.