Fix closing already closed channel on exit

game/game.go

@@ -410,7 +410,13 @@ func (g *Game) Cleanup() {
 			rl.UnloadMusicStream(g.AssetManager.Music)
 		}
 
-		close(g.quitChan)
+		// Only close the channel if it hasn't been closed yet
+		select {
+		case <-g.quitChan:
+			// Channel already closed, do nothing
+		default:
+			close(g.quitChan)
+		}
 	})
 }
 
@@ -491,7 +497,8 @@ func (g *Game) DrawMenu() {
 }
 
 func (g *Game) Shutdown() {
-	close(g.quitChan)
+	// Use the cleanup method which has channel-closing safety
+	g.Cleanup()
 }
 
 func (g *Game) HandleServerMessages(messages []*pb.ChatMessage) {

network/network.go

@@ -248,23 +248,43 @@ func ConnectToServer(username, password string, isRegistering bool) (net.Conn, i
 func HandleServerCommunication(conn net.Conn, playerID int32, player *types.Player, otherPlayers map[int32]*types.Player, quitChan <-chan struct{}) {
 	msgHandler := NewMessageHandler(conn)
 
+	// Create channels for coordinating goroutines
+	errChan := make(chan error, 1)
+	done := make(chan struct{})
+
+	// Create a WaitGroup to track both sender and receiver goroutines
+	var wg sync.WaitGroup
+	wg.Add(2) // One for sender, one for receiver
+
+	// Set up a deferred cleanup function
 	defer func() {
 		if r := recover(); r != nil {
 			log.Printf("Recovered from panic in HandleServerCommunication: %v", r)
 		}
+
+		// Close the done channel to signal both goroutines to exit
+		close(done)
+
+		// Wait for both goroutines to finish
+		wg.Wait()
+
+		// Close the connection
 		conn.Close()
+
+		// Close the player's QuitDone channel if it exists
 		if player.QuitDone != nil {
-			close(player.QuitDone)
+			select {
+			case <-player.QuitDone: // Check if it's already closed
+				// Already closed, do nothing
+			default:
+				close(player.QuitDone)
+			}
 		}
 	}()
 
 	actionTicker := time.NewTicker(types.ClientTickRate)
 	defer actionTicker.Stop()
 
-	// Create error channel for goroutine communication
-	errChan := make(chan error, 1)
-	done := make(chan struct{})
-
 	// Add a heartbeat ticker to detect connection issues
 	heartbeatTicker := time.NewTicker(5 * time.Second)
 	defer heartbeatTicker.Stop()
@@ -276,8 +296,14 @@ func HandleServerCommunication(conn net.Conn, playerID int32, player *types.Play
 		defer func() {
 			if r := recover(); r != nil {
 				log.Printf("Recovered from panic in message sender: %v", r)
-				errChan <- fmt.Errorf("message sender panic: %v", r)
+				select {
+				case errChan <- fmt.Errorf("message sender panic: %v", r):
+				default:
+					// Channel already closed or full, just log
+					log.Printf("Unable to send error: %v", r)
+				}
 			}
+			wg.Done() // Mark this goroutine as done
 		}()
 
 		for {
@@ -291,8 +317,11 @@ func HandleServerCommunication(conn net.Conn, playerID int32, player *types.Play
 						PlayerId: playerID,
 					}},
 				}
-				msgHandler.WriteMessage(disconnectMsg)
-				done <- struct{}{}
+
+				// Try to send disconnect message, ignoring errors
+				_ = msgHandler.WriteMessage(disconnectMsg)
+
+				// No need to signal done channel here, the main goroutine handles this
 				return
 			case <-done:
 				return
@@ -307,8 +336,11 @@ func HandleServerCommunication(conn net.Conn, playerID int32, player *types.Play
 					}
 					if err := msgHandler.WriteMessage(emptyBatch); err != nil {
 						log.Printf("Failed to send heartbeat: %v", err)
-						errChan <- err
-						return
+						select {
+						case errChan <- err:
+						case <-done:
+							return
+						}
 					}
 					lastMessageTime = time.Now()
 				}
@@ -327,8 +359,11 @@ func HandleServerCommunication(conn net.Conn, playerID int32, player *types.Play
 					player.Unlock()
 
 					if err := msgHandler.WriteMessage(batch); err != nil {
-						errChan <- err
-						return
+						select {
+						case errChan <- err:
+						case <-done:
+							return
+						}
 					}
 					lastMessageTime = time.Now()
 				} else {
@@ -343,14 +378,22 @@ func HandleServerCommunication(conn net.Conn, playerID int32, player *types.Play
 		defer func() {
 			if r := recover(); r != nil {
 				log.Printf("Recovered from panic in message receiver: %v", r)
-				errChan <- fmt.Errorf("message receiver panic: %v", r)
+				select {
+				case errChan <- fmt.Errorf("message receiver panic: %v", r):
+				default:
+					// Channel already closed or full, just log
+					log.Printf("Unable to send error: %v", r)
+				}
 			}
+			wg.Done() // Mark this goroutine as done
 		}()
 
 		for {
 			select {
 			case <-quitChan:
 				return
+			case <-done:
+				return
 			default:
 				serverMessage, err := msgHandler.ReadMessage()
 				if err != nil {
@@ -358,7 +401,11 @@ func HandleServerCommunication(conn net.Conn, playerID int32, player *types.Play
 						log.Printf("Network timeout: %v", err)
 					} else if err != io.EOF {
 						log.Printf("Network read error: %v", err)
-						errChan <- err
+						select {
+						case errChan <- err:
+						case <-done:
+							return
+						}
 					} else {
 						log.Printf("Connection closed by server")
 					}
@@ -375,19 +422,12 @@ func HandleServerCommunication(conn net.Conn, playerID int32, player *types.Play
 	select {
 	case <-quitChan:
 		log.Printf("Received quit signal, sending disconnect message")
-		// Send disconnect message
-		disconnectMsg := &pb.ActionBatch{
-			PlayerId: playerID,
-			Actions: []*pb.Action{{
-				Type:     pb.Action_DISCONNECT,
-				PlayerId: playerID,
-			}},
-		}
-		msgHandler.WriteMessage(disconnectMsg)
-		close(done)
+		// The cleanup will happen in the deferred function
+		return
 	case err := <-errChan:
 		log.Printf("Network error: %v", err)
-		close(done)
+		// The cleanup will happen in the deferred function
+		return
 	}
 }
 
@@ -420,7 +460,13 @@ func NewConnection(username, password string, isRegistering bool) (*Connection,
 
 func (c *Connection) Close() {
 	c.closeOnce.Do(func() {
-		close(c.quitChan)
+		select {
+		case <-c.quitChan: // Check if it's already closed
+			// Already closed, do nothing
+		default:
+			close(c.quitChan)
+		}
+
 		// Wait with timeout for network cleanup
 		select {
 		case <-c.quitDone:
@@ -428,6 +474,8 @@ func (c *Connection) Close() {
 		case <-time.After(500 * time.Millisecond):
 			log.Println("Network cleanup timed out")
 		}
+
+		// Make sure the connection is closed
 		c.conn.Close()
 	})
 }