Proof of concept for user sorting bug

poc.py

class User():
    def __lt__(self, other):
        return False

    def __eq__(self, other):
        return self.foo == other.foo


# Replicates https://github.com/pallets/jinja/blob/5ef70112a1ff19c05324ff889dd30405b1002044/src/jinja2/filters.py#L435-L437
def key_func(user):
    return [user]


users = [User(), User()]

# This passes
print(sorted(users))

# This raises on 3.11 and 3.13, but I’d expect it to pass on 3.11
print(sorted(users, key=key_func))