[MM-46516] P1 - Fix total message counting for top DM (#20858)

Automatic Merge

store/sqlstore/post_store.go

@@ -3009,7 +3009,7 @@ func (s *SqlPostStore) GetTopDMsForUserSince(userID string, since int64, offset
 		aggregator = "string_agg(distinct cm.UserId, ',') as Participants"
 	}
 
-	topDMsBuilder := s.getQueryBuilder().Select("vch.TotalMsgCount as MessageCount", aggregator, "vch.Id as ChannelId").FromSelect(channelSelector, "vch").
+	topDMsBuilder := s.getQueryBuilder().Select("count(p.Id) as MessageCount", aggregator, "vch.Id as ChannelId").FromSelect(channelSelector, "vch").
 		Join("ChannelMembers as cm on cm.ChannelId = vch.Id").
 		Join("Posts as p on p.ChannelId = vch.Id").
 		Where(sq.And{
@@ -3019,7 +3019,7 @@ func (s *SqlPostStore) GetTopDMsForUserSince(userID string, since int64, offset
 			sq.Eq{
 				"p.DeleteAt": 0,
 			},
-		}).GroupBy("vch.id", "vch.TotalMsgCount")
+		}).GroupBy("vch.id")
 
 	topDMsBuilder = topDMsBuilder.OrderBy("MessageCount DESC").Limit(uint64(limit + 1)).Offset(uint64(offset))
 
@@ -3054,6 +3054,8 @@ func postProcessTopDMs(s *SqlPostStore, userID string, topDMs []*model.TopDM, si
 			// channel with self
 			secondParticipantId = "-1"
 		} else {
+			// divide message count by 2, because it's counted twice due to channel memberships being 2 for dms.
+			topDM.MessageCount = topDM.MessageCount / 2
 			if participants[0] == userID {
 				secondParticipantId = participants[1]
 			} else {

store/storetest/post_store.go

@@ -4106,6 +4106,13 @@ func testGetTopDMsForUserSince(t *testing.T, ss store.Store, s SqlStore) {
 		UserId:    u2.Id,
 	})
 	require.NoError(t, err)
+	// create second post for u2: modify create at to a very old date to make sure it isn't counted
+	_, err = ss.Post().Save(&model.Post{
+		ChannelId: chUser2.Id,
+		UserId:    u2.Id,
+		CreateAt:  100,
+	})
+	require.NoError(t, err)
 	// for user-u3: 3 posts
 	for i := 0; i < 3; i++ {
 		_, err = ss.Post().Save(&model.Post{