MM-35125 CRT: Mention badge on threads doesn't appear until refresh (#17504)

store/opentracinglayer/opentracinglayer.go

@@ -8794,6 +8794,24 @@ func (s *OpenTracingLayerThreadStore) GetPosts(threadID string, since int64) ([]
 	return result, err
 }
 
+func (s *OpenTracingLayerThreadStore) GetThreadFollowers(threadID string) ([]string, error) {
+	origCtx := s.Root.Store.Context()
+	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ThreadStore.GetThreadFollowers")
+	s.Root.Store.SetContext(newCtx)
+	defer func() {
+		s.Root.Store.SetContext(origCtx)
+	}()
+
+	defer span.Finish()
+	result, err := s.ThreadStore.GetThreadFollowers(threadID)
+	if err != nil {
+		span.LogFields(spanlog.Error(err))
+		ext.Error.Set(span, true)
+	}
+
+	return result, err
+}
+
 func (s *OpenTracingLayerThreadStore) GetThreadForUser(userID string, teamID string, threadId string, extended bool) (*model.ThreadResponse, error) {
 	origCtx := s.Root.Store.Context()
 	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ThreadStore.GetThreadForUser")

store/retrylayer/retrylayer.go

@@ -9568,6 +9568,26 @@ func (s *RetryLayerThreadStore) GetPosts(threadID string, since int64) ([]*model
 
 }
 
+func (s *RetryLayerThreadStore) GetThreadFollowers(threadID string) ([]string, error) {
+
+	tries := 0
+	for {
+		result, err := s.ThreadStore.GetThreadFollowers(threadID)
+		if err == nil {
+			return result, nil
+		}
+		if !isRepeatableError(err) {
+			return result, err
+		}
+		tries++
+		if tries >= 3 {
+			err = errors.Wrap(err, "giving up after 3 consecutive repeatable transaction failures")
+			return result, err
+		}
+	}
+
+}
+
 func (s *RetryLayerThreadStore) GetThreadForUser(userID string, teamID string, threadId string, extended bool) (*model.ThreadResponse, error) {
 
 	tries := 0

store/sqlstore/thread_store.go

@@ -307,6 +307,21 @@ func (s *SqlThreadStore) GetThreadsForUser(userId, teamId string, opts model.Get
 
 	return result, nil
 }
+
+func (s *SqlThreadStore) GetThreadFollowers(threadID string) ([]string, error) {
+	var users []string
+	query, args, _ := s.getQueryBuilder().
+		Select("ThreadMemberships.UserId").
+		From("ThreadMemberships").
+		Where(sq.Eq{"PostId": threadID}).ToSql()
+	_, err := s.GetReplica().Select(&users, query, args...)
+
+	if err != nil {
+		return nil, err
+	}
+	return users, nil
+}
+
 func (s *SqlThreadStore) GetThreadForUser(userId, teamId, threadId string, extended bool) (*model.ThreadResponse, error) {
 	type JoinedThread struct {
 		PostId         string

store/store.go

@@ -272,6 +272,8 @@ type ChannelMemberHistoryStore interface {
 	PermanentDeleteBatch(endTime int64, limit int64) (int64, error)
 }
 type ThreadStore interface {
+	GetThreadFollowers(threadID string) ([]string, error)
+
 	SaveMultiple(thread []*model.Thread) ([]*model.Thread, int, error)
 	Save(thread *model.Thread) (*model.Thread, error)
 	Update(thread *model.Thread) (*model.Thread, error)

store/storetest/mocks/ThreadStore.go

@@ -157,6 +157,29 @@ func (_m *ThreadStore) GetPosts(threadID string, since int64) ([]*model.Post, er
 	return r0, r1
 }
 
+// GetThreadFollowers provides a mock function with given fields: threadID
+func (_m *ThreadStore) GetThreadFollowers(threadID string) ([]string, error) {
+	ret := _m.Called(threadID)
+
+	var r0 []string
+	if rf, ok := ret.Get(0).(func(string) []string); ok {
+		r0 = rf(threadID)
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).([]string)
+		}
+	}
+
+	var r1 error
+	if rf, ok := ret.Get(1).(func(string) error); ok {
+		r1 = rf(threadID)
+	} else {
+		r1 = ret.Error(1)
+	}
+
+	return r0, r1
+}
+
 // GetThreadForUser provides a mock function with given fields: userID, teamID, threadId, extended
 func (_m *ThreadStore) GetThreadForUser(userID string, teamID string, threadId string, extended bool) (*model.ThreadResponse, error) {
 	ret := _m.Called(userID, teamID, threadId, extended)

store/timerlayer/timerlayer.go

@@ -7926,6 +7926,22 @@ func (s *TimerLayerThreadStore) GetPosts(threadID string, since int64) ([]*model
 	return result, err
 }
 
+func (s *TimerLayerThreadStore) GetThreadFollowers(threadID string) ([]string, error) {
+	start := timemodule.Now()
+
+	result, err := s.ThreadStore.GetThreadFollowers(threadID)
+
+	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
+	if s.Root.Metrics != nil {
+		success := "false"
+		if err == nil {
+			success = "true"
+		}
+		s.Root.Metrics.ObserveStoreMethodDuration("ThreadStore.GetThreadFollowers", success, elapsed)
+	}
+	return result, err
+}
+
 func (s *TimerLayerThreadStore) GetThreadForUser(userID string, teamID string, threadId string, extended bool) (*model.ThreadResponse, error) {
 	start := timemodule.Now()