Fix sdiffstore

[mt3925]

No description provided.

[Grokzen]

Hi @mt3925
Could you please give a small example when/how it breaks so that i can understand why this is needed?

[mt3925]

Hi @Grokzen

def sdiffstore(self, dest, keys, *args):
    """
    Store the difference of sets specified by ``keys`` into a new
    set named ``dest``.  Returns the number of keys in the new set.
    Overwrites dest key if it exists.
    Cluster impl:
        Use sdiff() --> Delete dest key --> store result in dest key
    """
    res = self.sdiff(keys, *args)
    self.delete(dest)

    if not res:
        return 0
    return self.sadd(dest, *res)

The difference of sets specified by keys may be empty, but the argument res of the function sadd must be non-empty.

[Grokzen]

Hi @mt3925. I tested this manually and created a failing test to verify this was broken and that this fixes and it does properly. I will add the test and a line in the CHANGES file after merging this.

[coveralls]

Changes Unknown when pulling e38e874 on mt3925:unstable into ** on Grokzen:unstable**.