[ruff-format] flake8-class-newline

[oysstu]

Working on a codebase where flake8-class-newline is enforced. To quote that module:

PEP8 says we should surround every class method with a single blank line. However flake8 is ambiguous about the first method having a blank line above it.

The ruff formatter currently removes leading spaces after a class definition if there is no docstring. Honestly, I've seen more Python classes without a leading space before the first method than ones with a leading space, so I don't think adding a space should necessary be the default, but it would be nice to have an option for having it (or ignoring it if it exists).

Class without newline (current ruff formatting)

class AClassWithoutANewLine(object):
    def a_method(self):
        return 'a_value'

Class with newline (flake8-class-newline expected formatting)

class AClassWithoutANewLine(object):

    def a_method(self):
        return 'a_value'

When a docstring is present, ruff currently adds a space between the docstring and first method, which passes the flake8-class-newline linter.

[zanieb]

Thanks for the report; this is a duplicate of #8566 and I think the reasoning there stands. Happy to hear additional thoughts though.

[oysstu]

Aha, didn't find that issue when searching. Fair enough, I wish the PEP8 would be more explicit regarding this