Bugfix/host quit strands some players

Assets/BossRoom/Prefabs/State/MainMenuState.prefab

@@ -0,0 +1,45 @@
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Assets/BossRoom/Scripts/Client/Game/State/ClientMainMenuState.cs

@@ -19,5 +19,4 @@ public override void NetworkStart()
             //fortunately we know you are a client, because all players are clients when sitting at the main menu screen. 
         }
     }
-
 }

Assets/BossRoom/Scripts/Client/Game/State/ClientPostGameState.cs

@@ -1,3 +1,5 @@
+using UnityEngine;
+
 namespace BossRoom.Client
 {
     /// <summary>
@@ -8,6 +10,19 @@ public class ClientPostGameState : GameStateBehaviour
     {
         public override GameState ActiveState { get { return GameState.PostGame; } }
 
+        protected override void Start()
+        {
+            base.Start();
+
+            //it is common for the user to get dumped back to main menu from here (i.e., if the host decides not to play again), and
+            //it is a little funny to display a "Connection to Host Lost" message in that case. The best thing would probably be to
+            //display a "Host Abandoned the Game" message, but this would require some more plumbing (an RPC from the host before it quit,
+            //containing that information).
+            //In the meantime, we just set "UserRequested" to suppress the Disconnected error popup.
+            var portalGO = GameObject.FindGameObjectWithTag("GameNetPortal");
+            portalGO.GetComponent<ClientGameNetPortal>().DisconnectReason.SetDisconnectReason(DisconnectReasonType.UserRequested);
+        }
+
         public override void NetworkStart()
         {
             base.NetworkStart();

Assets/BossRoom/Scripts/Client/Net/ClientGameNetPortal.cs

@@ -18,6 +18,11 @@ public class ClientGameNetPortal : MonoBehaviour
     {
         private GameNetPortal m_Portal;
 
+        /// <summary>
+        /// If a disconnect occurred this will be populated with any contextual information that was available to explain why.
+        /// </summary>
+        public DisconnectReason DisconnectReason { get; private set; } = new DisconnectReason();
+
         /// <summary>
         /// Time in seconds before the client considers a lack of server response a timeout
         /// </summary>
@@ -42,6 +47,8 @@ void Start()
 
         private void NetworkStart()
         {
+            DisconnectReason.Clear();
+
             if (!m_Portal.NetManager.IsClient)
             {
                 enabled = false;
@@ -54,7 +61,7 @@ private void NetworkStart()
                     //only do this if a pure client, so as not to overlap with host behavior in ServerGameNetPortal.
                     m_Portal.UserDisconnectRequested += OnUserDisconnectRequest;
                 }
-                m_Portal.NetManager.OnClientDisconnectCallback += OnClientDisconnect;
+
                 SceneManager.sceneLoaded += OnSceneLoaded;
             }
         }
@@ -71,23 +78,11 @@ private void OnUserDisconnectRequest()
         {
             if( m_Portal.NetManager.IsClient )
             {
+                DisconnectReason.SetDisconnectReason(DisconnectReasonType.UserRequested);
                 m_Portal.NetManager.StopClient();
             }
         }
 
-        /// <summary>
-        /// Invoked whenever a client disconnects from the host. 
-        /// </summary>
-        private void OnClientDisconnect(ulong clientId)
-        {
-            if( clientId == m_Portal.NetManager.LocalClientId )
-            {
-                SceneManager.sceneLoaded -= OnSceneLoaded;
-                m_Portal.UserDisconnectRequested -= OnUserDisconnectRequest;
-                m_Portal.NetManager.OnClientDisconnectCallback -= OnClientDisconnect;
-            }
-        }
-
         private void OnConnectFinished(ConnectStatus status)
         {
             //on success, there is nothing to do (the MLAPI scene management system will take us to the next scene).
@@ -99,15 +94,25 @@ private void OnConnectFinished(ConnectStatus status)
 
         private void OnDisconnectOrTimeout(ulong clientID)
         {
-            if(clientID == MLAPI.NetworkManager.Singleton.LocalClientId )
+            // we could also check whether the disconnect was us or the host, but the "interesting" question is whether
+            //following the disconnect, we're no longer a Connected Client, so we just explicitly check that scenario.
+            if ( !MLAPI.NetworkManager.Singleton.IsConnectedClient )
             {
+                SceneManager.sceneLoaded -= OnSceneLoaded;
+                m_Portal.UserDisconnectRequested -= OnUserDisconnectRequest;
+
                 //On a client disconnect we want to take them back to the main menu.
                 //We have to check here in SceneManager if our active scene is the main menu, as if it is, it means we timed out rather than a raw disconnect;
                 if (UnityEngine.SceneManagement.SceneManager.GetActiveScene().name != "MainMenu")
                 {
                     // we're not at the main menu, so we obviously had a connection before... thus, we aren't in a timeout scenario.
                     // Just shut down networking and switch back to main menu.
                     MLAPI.NetworkManager.Singleton.Shutdown();
+                    if( !DisconnectReason.HasTransitionReason )
+                    {
+                        //disconnect that happened for some other reason than user UI interaction--should display a message.
+                        DisconnectReason.SetDisconnectReason(DisconnectReasonType.Disconnect);
+                    }
                     SceneManager.LoadScene("MainMenu");
                 }
                 else
@@ -129,7 +134,6 @@ private void OnDisconnectOrTimeout(ulong clientID)
         /// <param name="port">The port of the host to connect to. </param>
         public static void StartClient(GameNetPortal portal, string ipaddress, int port)
         {
-            //DMW_NOTE: non-portable. We need to be updated when moving to UTP transport.
             var chosenTransport = NetworkManager.Singleton.gameObject.GetComponent<TransportPicker>().IpHostTransport;
             NetworkManager.Singleton.NetworkConfig.NetworkTransport = chosenTransport;
 

Assets/BossRoom/Scripts/Client/Net/DisconnectReason.cs

@@ -0,0 +1,53 @@
+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+
+namespace BossRoom.Client
+{
+    /// <summary>
+    /// enum that records additional context for why a user was disconnected. The primary use case for this
+    /// is to allow the MainMenu to display an appropriate message after a disconnect event.
+    /// </summary>
+    public enum DisconnectReasonType
+    {
+        Undefined,      //no reason has been set. 
+        UserRequested,  //user explicitly requested a disconnect. 
+        Disconnect,     //client unexpectedly lost connection with host. 
+    }
+
+    /// <summary>
+    /// This class provides some additional context for the connection managed by the ClientGameNetPortal. If a disconnect occurrs, or is expected to occur, client
+    /// code can set the reason why here. Then subsequent code can interrogate this class to get the disconnect reason, and display appropriate information to
+    /// the user, even after a scene transition has occurred. The state is set back to Undefined if a new connection is begun.
+    /// </summary>
+    public class DisconnectReason
+    {
+        /// <summary>
+        /// When a disconnect is detected (or expected), set this to provide some context for why it occurred.
+        /// </summary>
+        public void SetDisconnectReason( DisconnectReasonType reason)
+        {
+            //using an explicit setter here rather than the auto-property, to make the code locations where disconnect information is set more obvious.
+            Reason = reason;
+        }
+
+        /// <summary>
+        /// The reason why a disconnect occurred, or Undefined if not set.
+        /// </summary>
+        public DisconnectReasonType Reason { get; private set; } = DisconnectReasonType.Undefined;
+
+        /// <summary>
+        /// Clear the DisconnectReason, returning it to Undefined.
+        /// </summary>
+        public void Clear()
+        {
+            Reason = DisconnectReasonType.Undefined;
+        }
+
+        /// <summary>
+        /// Has a TransitionReason already be set? (The TransitionReason provides context for why someone transition back to the MainMenu, and is a one-use item
+        /// that is unset as soon as it is read).
+        /// </summary>
+        public bool HasTransitionReason => Reason != DisconnectReasonType.Undefined;
+    }
+}

Assets/BossRoom/Scripts/Client/UI/MainMenuUI.cs

@@ -33,6 +33,11 @@ void Start()
 
             m_ClientNetPortal.NetworkTimedOut += OnNetworkTimeout;
             m_ClientNetPortal.ConnectFinished += OnConnectFinished;
+
+            if (m_ClientNetPortal.DisconnectReason.Reason == DisconnectReasonType.Disconnect )
+            {
+                m_ResponsePopup.SetupNotifierDisplay("Disconnected From Host", "The connection to the Host was lost", false, true );
+            }
         }
 
         public void OnHostClicked()