Formatter: Allow comments between and/or and the right hand side

[konstin]

The following input is stable with black ...

if (
    a
    # own line comment between left hand side and `and`
    and
    # own line comment between `and` and right hand side
    b
):
    pass

... but we move the second own line comment before the and:

if (
    a
    # own line comment between left hand side and `and`
    # own line comment between `and` and right hand side
    and b
):
    pass

The behavior is the same with or, but + works, i.e. other binary expressions work but not boolean expressions.

[MichaReiser]

We may want to generalize the formatting of all BinaryLike nodes to achieve consistent formatting.

[MichaReiser]

I actually prefer our formatting over black's and it preserves the comment ordering. But we should align the comment placement for all binary like expressions.

[zanieb]

I agree with Micha that our formatting is more readable at the expense of possibly overriding user intent. I don't see what extra context can be given by having the comment after the operator though.

[MichaReiser]

I guess the challenge with the current formatting is how to handle trailing and comments and preserve the comment line position and order: Playground

I think my preferred formatting is:

if (
    a
    # own line comment between left hand side and `and`
    # trailing
    # own line comment between `and` and right hand side
    and b
):
    pass

It preserves the order, but changes trailing to an own linecomment. But I think this overall looks better.

Edit: Similar issue #6647

[MichaReiser]

And this is another funny one CC: @charliermarsh You best run our formatter on django and take a look at the diff. There are plenty of examples.

[charliermarsh]

I can take it on.

[MichaReiser]

Thank you @charliermarsh

If possible, could we align the comment handling with the binary expression formatting? It's very likely that I have to unify the two implementations and that would be significantly easier if they roughly work the same.

[MichaReiser]

It turns out that the string formatting doesn't overlap with and or formatting. It only affects binary and comparison expressions. That means this is still up for grabs.

Overall, the binary / compare formatting seems very reasonable. Maybe we can mimick that formatting for boolean expressions

[MichaReiser]

@charliermarsh do you plan to work on this next week? If not, @konstin would you be interested in taking a look. It's our biggest difference in Django by now or I'll try to have a look since it's related to binary expression formatting.

[charliermarsh]

@konstin - please go ahead! Haven’t started on it at all.

[MichaReiser]

@konstin sorry for the forth and back. I consider rewriting the boolean expression formatting to use the BinaryLike formatting (the same logic as the binary and compare expressions use) to fix #7004 just once rather than in two places. Maybe... just maybe, it fixes this difference too