fix: #1515 - StopHost now invokes OnServerDisconnected for the host client too (#1601)

* fix: #1515 - StopHost now invokes OnServerDisconnected for the host client too

* avoid NullReferenceException when calling StopHost without StartHost

* test WIP

* test

Assets/Mirror/Runtime/NetworkClient.cs

@@ -124,6 +124,23 @@ internal static void ConnectLocalServer()
             NetworkServer.localConnection.Send(new ConnectMessage());
         }
 
+        /// <summary>
+        /// disconnect host mode. this is needed to call DisconnectMessage for
+        /// the host client too.
+        /// </summary>
+        internal static void DisconnectLocalServer()
+        {
+            // only if host connection is running
+            if (NetworkServer.localConnection != null)
+            {
+                // TODO ConnectLocalServer manually sends a ConnectMessage to the
+                // local connection. should we send a DisconnectMessage here too?
+                // (if we do then we get an Unknown Message ID log)
+                //NetworkServer.localConnection.Send(new DisconnectMessage());
+                NetworkServer.OnDisconnected(NetworkServer.localConnection.connectionId);
+            }
+        }
+
         static void InitializeTransportHandlers()
         {
             Transport.activeTransport.OnClientConnected.AddListener(OnConnected);

Assets/Mirror/Runtime/NetworkManager.cs

@@ -547,6 +547,15 @@ void StartHostClient()
         public void StopHost()
         {
             OnStopHost();
+
+            // TODO try to move DisconnectLocalServer into StopClient(), and
+            // then call StopClient() before StopServer(). needs testing!.
+
+            // DisconnectLocalServer needs to be called so that the host client
+            // receives a DisconnectMessage too.
+            // fixes: https://github.com/vis2k/Mirror/issues/1515
+            NetworkClient.DisconnectLocalServer();
+
             StopServer();
             StopClient();
         }

Assets/Mirror/Runtime/NetworkServer.cs

@@ -473,7 +473,7 @@ internal static void OnConnected(NetworkConnectionToClient conn)
             conn.InvokeHandler(new ConnectMessage(), -1);
         }
 
-        static void OnDisconnected(int connectionId)
+        internal static void OnDisconnected(int connectionId)
         {
             if (LogFilter.Debug) Debug.Log("Server disconnect client:" + connectionId);
 

Assets/Mirror/Tests/Editor/NetworkManagerStopHostOnServerDisconnectedTest.cs

@@ -0,0 +1,43 @@
+using NUnit.Framework;
+using UnityEngine;
+
+namespace Mirror.Tests
+{
+    class NetworkManagerOnServerDisconnect : NetworkManager
+    {
+        public int called;
+        public override void OnServerDisconnect(NetworkConnection conn) { ++called; }
+    }
+
+    [TestFixture]
+    public class NetworkManagerStopHostOnServerDisconnectedTest
+    {
+        GameObject gameObject;
+        NetworkManagerOnServerDisconnect manager;
+
+        [SetUp]
+        public void SetUp()
+        {
+            gameObject = new GameObject();
+            manager = gameObject.AddComponent<NetworkManagerOnServerDisconnect>();
+        }
+
+        [TearDown]
+        public void TearDown()
+        {
+            GameObject.DestroyImmediate(gameObject);
+        }
+
+        // test to prevent https://github.com/vis2k/Mirror/issues/1515
+        [Test]
+        public void StopHostCallsOnServerDisconnectForHostClient()
+        {
+            // OnServerDisconnect is always called when a client disconnects.
+            // it should also be called for the host client when we stop the host
+            Assert.That(manager.called, Is.EqualTo(0));
+            manager.StartHost();
+            manager.StopHost();
+            Assert.That(manager.called, Is.EqualTo(1));
+        }
+    }
+}

Assets/Mirror/Tests/Editor/NetworkManagerStopHostOnServerDisconnectedTest.cs.meta

@@ -0,0 +1,11 @@
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+guid: 2f583081473a64b92b971678e571382a
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
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Assets/Mirror/Tests/Editor/NetworkManagerTest.cs

@@ -114,7 +114,7 @@ public void RegisterStartPositionTest()
         public void UnRegisterStartPositionTest()
         {
             Assert.That(NetworkManager.startPositions.Count , Is.Zero);
-            
+
             NetworkManager.RegisterStartPosition(gameObject.transform);
             Assert.That(NetworkManager.startPositions.Count , Is.EqualTo(1));
             Assert.That(NetworkManager.startPositions, Has.Member(gameObject.transform));
@@ -127,7 +127,7 @@ public void UnRegisterStartPositionTest()
         public void GetStartPositionTest()
         {
             Assert.That(NetworkManager.startPositions.Count , Is.Zero);
-            
+
             NetworkManager.RegisterStartPosition(gameObject.transform);
             Assert.That(NetworkManager.startPositions.Count , Is.EqualTo(1));
             Assert.That(NetworkManager.startPositions, Has.Member(gameObject.transform));