LP-5673: fixed a problem with duplicate notifications in a channel

server/utils.go

@@ -201,7 +201,14 @@ func (p *Plugin) notifyGrant(badgeID badgesmodel.BadgeID, granter string, grante
 				p.mm.Log.Debug("notify subscription error", "err", err)
 			}
 		}
-		if inChannel {
+		alreadyNotified := false
+		for _, sub := range subs {
+			if sub == channelID {
+				alreadyNotified = true
+				break
+			}
+		}
+		if inChannel && !alreadyNotified {
 			if !p.API.HasPermissionToChannel(granter, channelID, model.PERMISSION_CREATE_POST) {
 				Tg := p.getT(granterUser.Locale)
 				p.mm.Post.SendEphemeralPost(granter, &model.Post{Message: Tg("badges.notify.no_permission_channel", "У вас нет прав на отправку уведомления о выдаче в этот канал."), ChannelId: channelID})