Make "failed to update lobby" a warning, and add information

internal/signaling/peer.go

@@ -470,7 +470,7 @@ func (p *Peer) HandleUpdatePacket(ctx context.Context, packet LobbyUpdatePacket)
 
 	err := p.store.UpdateCustomData(ctx, p.Game, p.Lobby, p.ID, packet.Public, packet.CustomData, packet.CanUpdateBy)
 	if err != nil {
-		logger.Error("failed to update lobby", zap.Error(err), zap.Any("customData", packet.CustomData))
+		logger.Warn("failed to update lobby", zap.Error(err), zap.Any("customData", packet.CustomData))
 		util.ReplyError(ctx, p.conn, fmt.Errorf("unable to update lobby: %v", err))
 		return nil
 	}

internal/signaling/stores/postgres.go

@@ -634,14 +634,14 @@ func (s *PostgresStore) UpdateCustomData(ctx context.Context, game, lobby, peer
 		// No restrictions.
 	case CanUpdateByCreator:
 		if creator != peer {
-			return ErrNotAllowed
+			return errors.New("not allowed: peer is not the creator")
 		}
 	case CanUpdateByLeader:
 		if leader != peer {
-			return ErrNotAllowed
+			return errors.New("not allowed: peer is not the leader")
 		}
 	default:
-		return ErrNotAllowed
+		return fmt.Errorf("invalid can_update_by value: %q", currentCanUpdateBy)
 	}
 
 	columns := make([]string, 0, 3)

internal/signaling/stores/shared.go

@@ -12,7 +12,6 @@ var ErrNotFound = errors.New("lobby not found")
 var ErrNoSuchTopic = errors.New("no such topic")
 var ErrInvalidLobbyCode = errors.New("invalid lobby code")
 var ErrInvalidPeerID = errors.New("invalid peer id")
-var ErrNotAllowed = errors.New("not allowed")
 
 type SubscriptionCallback func(context.Context, []byte)