class Node:
    def __init__(self, edges = set()):
        self.edges = edges


def main():
    foo = Node()
    bar = Node()
    quz = Node()

    foo.edges.add(bar)
    bar.edges.add(foo)

    assert(foo is not bar) # assertion succeeds
    assert(foo is not quz) # assertion succeeds
    assert(bar is not quz) # assertion succeeds
    assert(len(quz.edges) == 0) # assertion fails??


main()

spoiler

Mutable default values are shared across objects. The set in this case.

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[–] FizzyOrange 2 points 5 days ago (5 children)

Yeah Pylint catches this. If you aren't using Pylint you are writing bad Python.

[–] [email protected] 6 points 5 days ago (4 children)

That's a funny way to spell Ruff

[–] FizzyOrange 3 points 4 days ago (3 children)

Yeah I tried Ruff about a year ago and it only had really trivial lints so it wasn't a good replacement for Pylint. Is it on par yet?

[–] NostraDavid 2 points 4 days ago

It has implemented about half - I would check which the important ones are, and check if it's been implemented (which is being tracked in issue 970):

https://github.com/astral-sh/ruff/issues/970

Astral claims Ruff has more rules total (about 800), but implemented about half of Pylint (which has 400 rules, so 200 implemented).

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