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invalid-hash-return-type (PLE0309)#

Derived from the Pylint linter.

This rule is unstable and in preview. The --preview flag is required for use.

What it does#

Checks for __hash__ implementations that return a value other than an integer.

Why is this bad?#

The __hash__ method should return an integer. Returning a different type may cause unexpected behavior.

Note: bool is a subclass of int, so it's technically valid for __hash__ to return True or False. However, for consistency with other rules, Ruff will still raise when __hash__ returns a bool.


class Foo:
    def __hash__(self):
        return "2"

Use instead:

class Foo:
    def __hash__(self):
        return 2