ChannelStore migration Part 2 (#15405)

* Migration completed

* Several corrections in tests

* Fix imports

* Fix some errors after testing

* Trigger CI

* Fix tests

* Suggestions

* Suggestions

* Add license

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

app/post.go

@@ -1292,12 +1292,12 @@ func (a *App) countMentionsFromPost(user *model.User, post *model.Post) (int, *m
 
 	if channel.Type == model.CHANNEL_DIRECT {
 		// In a DM channel, every post made by the other user is a mention
-		count, countErr := a.Srv().Store.Channel().CountPostsAfter(post.ChannelId, post.CreateAt-1, channel.GetOtherUserIdForDM(user.Id))
-		if countErr != nil {
-			return 0, countErr
+		count, nErr := a.Srv().Store.Channel().CountPostsAfter(post.ChannelId, post.CreateAt-1, channel.GetOtherUserIdForDM(user.Id))
+		if nErr != nil {
+			return 0, model.NewAppError("countMentionsFromPost", "app.channel.count_posts_since.app_error", nil, nErr.Error(), http.StatusInternalServerError)
 		}
 
-		return count, countErr
+		return count, nil
 	}
 
 	channelMember, err := a.GetChannelMember(channel.Id, user.Id)