`smembers` returns `list` not `set`

[tuukkamustonen]

The smembers is defined as:

    def smembers(self, name: str) -> Union[Awaitable[Set], Set]:

But it doesn't return a set:

from fakeredis import FakeValkey


def main() -> None:
    client = FakeValkey()
    client.sadd("demo:set", "alpha", "beta")

    members = client.smembers("demo:set")

    print(f"smembers() returned: {members!r}")
    print(f"type: {type(members).__name__}")


if __name__ == "__main__":
    main()

Output:

smembers() returned: [b'beta', b'alpha']
type: list

[mkmkme]

Hey! Thanks for the report. This is going to be fixed by #265, and will be released as part of 7.0.0.

[tuukkamustonen]

@mkmkme That PR adjusts the type hints, but the fix needed would be to have the method return set not list, right?

The PR is now making a reverse, changing the return type to list from set here.

But the API is about sets, no duplicates allowed, so returning Python set would be a better choice, no?

[mkmkme]

Yes, you're right. Thanks! I'll reopen the issue. I'll fix it, but I still think it would target 7.0.0 since technically it's a breaking change. Some people might actually expect list there.

According to the documentation, SMEMBERS should have an Array response in RESP2 and Set response in RESP3. We can make it protocol-dependant (so having Valkey(protocol=3) would return an actual set), but it might be even better to return a set unconditionally.

[mkmkme]

I can see that actually it was my change that replaced the set response with a list one here: 414963f

However, I would argue that the change itself was probably incorrect and we didn't necessarily need to have that return type change. I will investigate it further and will try to fix it back.

[mkmkme]

So I believe the reason I've made this change was that during properly implementing libvalkey-py I realised that technically RESP3 can contain sets of unhashable data, e.g. sets of dicts.

It's likely that realistically it can't be stored. I will see if I can actually store it in Valkey itself and will fix it if I can't.