Handle empty partial indexes

Author: WaVEV

django_mongodb/query.py

@@ -325,9 +325,9 @@ def where_node_idx(self, compiler, connection):
                 full_needed -= 1
 
     if empty_needed == 0:
-        raise (FullResultSet if self.negated else EmptyResultSet)
+        raise EmptyResultSet
     if full_needed == 0:
-        raise (EmptyResultSet if self.negated else FullResultSet)
+        return {}
 
     if len(children_mql) == 1:
         mql = children_mql[0]