Scan includes expired keys

[tommikaikkonen]

I'm not sure if this is the desired functionality, but using scan and scan_iter includes expired keys.

Here is how to reproduce (just save to file and run with python3)

from fakeredis import FakeStrictRedis
from time import sleep


def main():
    redis = FakeStrictRedis()
    redis.set('expiringkey', 'value')
    redis.expire('expiringkey', 0)

    sleep(1)

    keys = list(redis.scan_iter())
    print(keys)  # prints [b'expiringkey'], expected []


if __name__ == '__main__':
    main()

Looks like the culprit is the __iter__ implementation of _StrKeyDict, which doesn't call self._update_expired_keys() like __getitem__ does. I suppose it should be called before returning the iterator, resulting in keys being expired at the start of each scan call.

If this is indeed a bug and my solution sounds good, I can submit a PR.

[bmerry]

I think your analysis is correct. The implementation has changed quite a bit, but the issue still remains, and could be fixed by overriding keys to filter out expired keys.