fix: Infinite NetworkManager.ShutdownInternal on NetworkTransport.DisconnectLocalClient Exception [MTT-5551] (#2433)

* fix

Prevent an infinite shutdown sequence from happening if NetworkTransport.DisconnectLocalClient throws an exception during NetworkManager.ShutdownInternal.

If UnityTransport.FlushSendQueuesForClientId throws an exception, log the exception and allow the invoking method to continue processing.

Author: NoelStephensUnity

com.unity.netcode.gameobjects/Runtime/Core/NetworkManager.cs

@@ -1197,10 +1197,22 @@ internal void ShutdownInternal()
                 }
             }
 
+            // Unregister network updates before trying to disconnect the client
+            this.UnregisterAllNetworkUpdates();
+
             if (IsClient && IsListening)
             {
                 // Client only, send disconnect to server
-                NetworkConfig.NetworkTransport.DisconnectLocalClient();
+                // If transport throws and exception, log the exception and
+                // continue the shutdown sequence (or forever be shutting down)
+                try
+                {
+                    NetworkConfig.NetworkTransport.DisconnectLocalClient();
+                }
+                catch (Exception ex)
+                {
+                    Debug.LogException(ex);
+                }
             }
 
             IsConnectedClient = false;
@@ -1221,8 +1233,6 @@ internal void ShutdownInternal()
             IsServer = false;
             IsClient = false;
 
-            this.UnregisterAllNetworkUpdates();
-
             if (NetworkTickSystem != null)
             {
                 NetworkTickSystem.Tick -= OnNetworkManagerTick;

com.unity.netcode.gameobjects/Runtime/Transports/UTP/UnityTransport.cs

@@ -763,6 +763,10 @@ public void Execute()
         // Send as many batched messages from the queue as possible.
         private void SendBatchedMessages(SendTarget sendTarget, BatchedSendQueue queue)
         {
+            if (!m_Driver.IsCreated)
+            {
+                return;
+            }
             new SendBatchedMessagesJob
             {
                 Driver = m_Driver.ToConcurrent(),