MM-34609 Mark-as-unread on a post in a thread should cause auto-follow (#17343)

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

app/channel.go

@@ -2385,6 +2385,9 @@ func (a *App) MarkChannelAsUnreadFromPost(postID string, userID string) (*model.
 		}
 
 		threadMembership, _ := a.Srv().Store.Thread().GetMembershipForUser(user.Id, threadId)
+		if threadMembership == nil {
+			threadMembership, _ = a.Srv().Store.Thread().MaintainMembership(user.Id, threadId, true, true, true, true)
+		}
 		if threadMembership != nil && threadMembership.Following {
 			channel, nErr := a.Srv().Store.Channel().Get(post.ChannelId, true)
 			if nErr != nil {

app/notification.go

@@ -185,7 +185,7 @@ func (a *App) SendNotifications(post *model.Post, team *model.Team, channel *mod
 			go func(userID string) {
 				defer close(mac)
 				_, incrementMentions := mentions.Mentions[userID]
-				err := a.Srv().Store.Thread().MaintainMembership(userID, post.RootId, true, incrementMentions, *a.Config().ServiceSettings.ThreadAutoFollow, userID == post.UserId)
+				_, err := a.Srv().Store.Thread().MaintainMembership(userID, post.RootId, true, incrementMentions, *a.Config().ServiceSettings.ThreadAutoFollow, userID == post.UserId)
 				if err != nil {
 					mac <- model.NewAppError("SendNotifications", "app.channel.autofollow.app_error", nil, err.Error(), http.StatusInternalServerError)
 					return

app/user.go

@@ -2424,7 +2424,7 @@ func (a *App) UpdateThreadsReadForUser(userID, teamID string) *model.AppError {
 }
 
 func (a *App) UpdateThreadFollowForUser(userID, teamID, threadID string, state bool) *model.AppError {
-	err := a.Srv().Store.Thread().MaintainMembership(userID, threadID, state, false, true, false)
+	_, err := a.Srv().Store.Thread().MaintainMembership(userID, threadID, state, false, true, false)
 	if err != nil {
 		return model.NewAppError("UpdateThreadFollowForUser", "app.user.update_thread_follow_for_user.app_error", nil, err.Error(), http.StatusInternalServerError)
 	}