SINTER[STORE] requires keys to be sets

Jochen Sprickerhof · bmerry · commit 935eb4e76465 · 2021-10-25T14:27:51.000+02:00
Starting with Redis 6.0.15 this behaviour changed. The definition of SINTER[STORE] states: "Keys that do not exist are considered to be empty sets." At the same time SINTER only accepts set: "intersection of all the given sets" Both quotes from: https://redis.io/commands/sinter. The behaviour of Redis 6.0.14 was that it ignored the type of later keys if it found an empty set and returned that. Radis 6.0.15 changed this behaviour to return a WRONGTYPE if it finds a non set key in the arguments. Example to reproduce: 127.0.0.1:6379> FLUSHALL OK 127.0.0.1:6379> SINTER a b (empty array) 127.0.0.1:6379> SET b something OK 127.0.0.1:6379> SINTER a b (error) WRONGTYPE Operation against a key holding the wrong kind of value Cf. redis/redis#9273.
diff --git a/fakeredis/_server.py b/fakeredis/_server.py
@@ -1902,13 +1902,11 @@ def sdiff(self, *keys):
     def sdiffstore(self, dst, *keys):
         return self._setop(lambda a, b: a - b, False, dst, *keys)
 
-    # The following keys can't be marked as sets because of the
-    # stop_if_empty early-out.
-    @command((Key(set),), (Key(),))
+    @command((Key(set),), (Key(set),))
     def sinter(self, *keys):
         return self._setop(lambda a, b: a & b, True, None, *keys)
 
-    @command((Key(), Key(set)), (Key(),))
+    @command((Key(), Key(set)), (Key(set),))
     def sinterstore(self, dst, *keys):
         return self._setop(lambda a, b: a & b, True, dst, *keys)
 
