DistinctByParticipants SQL bug fix

The previous SQL returned any conversation which is the superset of the given participants. The fix is to add one more checking, which verifies each conversation size is exactly the same as the number of given participants. Connects #201
SkygearIO · Mar 1, 2018 · 34c90c1 · 34c90c1
1 parent a5da579
commit 34c90c1
Showing 1 changed file with 16 additions and 14 deletions.
diff --git a/chat/conversation_handlers.py b/chat/conversation_handlers.py
@@ -37,20 +37,22 @@ def __validate_conversation(participants):
     first_row = None
     with db.conn() as conn:
         result = conn.execute("""
-                              SELECT c._id FROM
-                                %(schema_name)s.conversation AS c
-                                WHERE
-                                    c.distinct_by_participants = TRUE
-                                AND
-                                (
-                                    SELECT COUNT(DISTINCT uc.user)
-                                    FROM %(schema_name)s.user_conversation
-                                    AS uc
-                                    WHERE
-                                        uc.conversation = c._id
-                                    AND
-                                        uc.user IN %(user_ids)s
-                                ) = %(count)s
+                              SELECT c._id
+                                   FROM %(schema_name)s.conversation AS c
+                              WHERE c._id IN (
+                                  SELECT uc.conversation
+                                  FROM %(schema_name)s.user_conversation AS uc
+                                  WHERE uc.conversation IN (
+                                      SELECT uc.conversation
+                                      FROM %(schema_name)s.user_conversation
+                                      AS uc
+                                      WHERE uc.user IN %(user_ids)s
+                                      GROUP BY uc.conversation
+                                      HAVING
+                                          COUNT(DISTINCT uc.user) = %(count)s)
+                                  GROUP BY uc.conversation
+                                  HAVING COUNT(DISTINCT uc.user) = %(count)s)
+                              ORDER BY c._created_at DESC
                               """, {'schema_name': AsIs(_get_schema_name()),
                                     'user_ids': tuple(participants),
                                     'count': len(participants)})