Consecutive calls of poe format can make additional changes.

[opcode81]

In our latest project I have repeatedly encountered a case where I would format, commit, then change an unrelated file, format again and find that it also changes the (unmodified) previously formatted file. Typically, it will add a minor thing like a trailing comma. Here's an example:

Starting point:

class SVGVariations:
    pass


class Foo:
    def create_variations_sequentially_from_example(self, example_variations: SVGVariations) -> SVGVariations:
        return example_variations

After first poe format:

class SVGVariations:
    pass


class Foo:
    def create_variations_sequentially_from_example(
        self, example_variations: SVGVariations
    ) -> SVGVariations:
        return example_variations

Second poe format:

class SVGVariations:
    pass


class Foo:
    def create_variations_sequentially_from_example(
        self,
        example_variations: SVGVariations,
    ) -> SVGVariations:
        return example_variations

[opcode81]

I found that this is caused by ruff rule COM812, which adds the trailing comma on the second run. I suppose it decides that the comma needs to be added only if the parameters are on a separate line/span more than one line.
It's a stupid rule, which we can do without.