Implement a recursive check for RUF060

[naslundx]

Summary

The existing implementation of RUF060 (InEmptyCollection) is not recursive, meaning that although set([]) results in an empty collection, the existing code fails it because set is taking an argument.

The updated implementation allows set and frozenset to take empty collection as positional argument (which results in empty set/frozenset).

Test Plan

Added test cases for recursive cases + updated snapshot (see RUF060.py).

[github-actions]

ruff-ecosystem results

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[ntBre]

Thanks!

[ntBre]

Actually, is this part correct? I tested locally and

frozenset() in {frozenset()}

is getting a diagnostic now, even though Python returns True:

>>> frozenset() in {frozenset()}
True

I think we may need to limit the recursive case to calls like down below.

[naslundx]

Oh, that's a very good find. Indeed, I did not consider the difference between how the two ways of constructing a set differ

>>> set([frozenset()]) == {frozenset()}  # note the [...]
True

Will fix

[naslundx]

Did not expect this either, but...

>>> len({""})
1

>>> len(set(""))
0

[ntBre]

Ah that is a funny one, calling set on a string will create a set of the characters:

>>> set("123")
{'1', '2', '3'}

so the empty string gives the empty set.

[Avasam]

Classic str is an Iterable[str] ^-^

[naslundx]

Thanks @ntBre - I reduced the PR but added some more test cases from comments above. (changes in new commit)

[ntBre]

Thanks!