collapsible-else-if (PLR5501) --fix removes comments

[sylvestre]

Trying to reformat firefox code with ruff https://phabricator.services.mozilla.com/D223851#inline-1243679
we noticed a bug with collapsible-else-if - https://docs.astral.sh/ruff/rules/collapsible-else-if/#collapsible-else-if-plr5501

take this case:

def check_sign(value: int) -> None:
    if value > 0:
        print("Number is positive.")
    else:
	# my comment to explain this
	# but will be removed
        if value < 0:
            print("Number is negative.")
        else:
            print("Number is zero.")

Then, with ruff main (ec72e67)

cargo run -p ruff -- check --select PLR5501 foo.py --no-cache  --fix  
Found 1 error (1 fixed, 0 remaining).

will update the code to:

def check_sign(value: int) -> None:
    if value > 0:
        print("Number is positive.")
    elif value < 0:
        print("Number is negative.")
    else:
        print("Number is zero.")

which removed my comment

[sylvestre]

cc @diceroll123 as it seems that you are the original author

[MichaReiser]

Related to #9790

[MichaReiser]

@sylvestre where would you expect the comment to be placed after the fix?

[sylvestre]

Good point.
To keep it relevant, I would continue on the line #elif and move on the next line

[zanieb]

We have test coverage for this behavior already at

ruff/crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__PLR5501_collapsible_else_if.py.snap

Lines 73 to 84 in 0f674d1

	52 52 | def not_ok1_with_comments():
	53 53 | if 1:
	54 54 | pass
	55 |+ elif 2:
	56 |+ pass
	55 57 | else:
	56 |- # inner comment
	57 |- if 2:
	58 |- pass
	59 |- else:
	60 |- pass # final pass comment
	58 |+ pass # final pass comment

[sylvestre]

Thanks!