Indent multi-line expressions in function arguments

[edaqa-uncountable]

Would it be possible to add an option to allow indentation of multi-line expressions in function arguments? Currently it aligns everything to the left with the other arguments.

For example, this is the formatting I get:

some_func(
   param_one=value,
   param_two="hi"
   if some_cond
   else "bye",
   param_three=1
   if some_cond
   else 2,
)

That alignment is hard to read. I want something like this instead:

some_func(
   param_one=value,
   param_two="hi"
       if some_cond
       else "bye",
   param_three=1
       if some_cond
       else 2,
)

I've shortened the lines to focus on the alignment (though I realize this short they might end up on one-line)

I admit I don't know what the ideal formatting here is, but the first one is definitely not it. Perhaps it should always rewrite as a paren expression, which has nicer results.

some_func(
   param_one=value,
   param_two=(
       "hi"
       if some_cond
       else "bye"
   ),
   param_three=(
       1
       if some_cond
       else 2
   )
)

Keywords: indent function argument parameter

[MichaReiser]

I agree, that Ruff's current nested expression formatting isn't ideal (for example, the formatting of the if else expression) and I explained my thinking around it in psf/black#4123 (and why we deviate from black).

We plan to revisit sub-expression formatting. I just created #12856 to make this more visible.

Therefore, yes we want to improve nested if expression formatting although I'm not sure if it will use the exact style that you're proposing.