memory, plugin XEP-0045: getMainResource returns None when asking a MUC entity + fixes /whois on a MUC (bare) entity

src/memory/memory.py

@@ -514,6 +514,11 @@ class Memory(object):
         """
         if entity_jid.resource:
             raise ValueError("getMainResource must be used with a bare jid (got {})".format(entity_jid))
+        try:
+            if self.host.plugins["XEP-0045"].isRoom(entity_jid, profile_key):
+                return None  # MUC rooms have no main resource
+        except KeyError:  # plugin not found
+            pass
         resources = self.getAllResources(entity_jid, profile_key)
         priority_resources = []
         for resource in resources: