Fix order of ClientConnected and ClientDisconnected events.

Source/MQTTnet/Server/IMqttClientSession.cs

@@ -14,7 +14,7 @@ namespace MQTTnet.Server
         void EnqueueApplicationMessage(MqttClientSession senderClientSession, MqttPublishPacket publishPacket);
         void ClearPendingApplicationMessages();
         
-        Task<bool> RunAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter);
+        Task RunAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter);
         void Stop(MqttClientDisconnectType disconnectType);
 
         Task SubscribeAsync(IList<TopicFilter> topicFilters);

Source/MQTTnet/Server/MqttClientSession.cs

@@ -65,7 +65,7 @@ namespace MQTTnet.Server
             status.LastNonKeepAlivePacketReceived = _keepAliveMonitor.LastNonKeepAlivePacketReceived;
         }
 
-        public async Task<bool> RunAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter)
+        public async Task RunAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter)
         {
             if (connectPacket == null) throw new ArgumentNullException(nameof(connectPacket));
             if (adapter == null) throw new ArgumentNullException(nameof(adapter));
@@ -129,8 +129,6 @@ namespace MQTTnet.Server
                 _cancellationTokenSource?.Dispose();
                 _cancellationTokenSource = null;
             }
-
-            return _wasCleanDisconnect;
         }
 
         public void Stop(MqttClientDisconnectType type)
@@ -157,6 +155,8 @@ namespace MQTTnet.Server
             finally
             {
                 _logger.Info("Client '{0}': Session stopped.", ClientId);
+
+                _sessionsManager.Server.OnClientDisconnected(ClientId, _wasCleanDisconnect);
             }
         }
 

Source/MQTTnet/Server/MqttClientSessionsManager.cs

@@ -125,6 +125,7 @@ namespace MQTTnet.Server
             {
                 _sessions.Remove(clientId);
             }
+
             _logger.Verbose("Session for client '{0}' deleted.", clientId);
         }
 
@@ -207,8 +208,7 @@ namespace MQTTnet.Server
         private async Task RunSession(IMqttChannelAdapter clientAdapter, CancellationToken cancellationToken)
         {
             var clientId = string.Empty;
-            var wasCleanDisconnect = false;
-
+            
             try
             {
                 var firstPacket = await clientAdapter.ReceivePacketAsync(_options.DefaultCommunicationTimeout, cancellationToken).ConfigureAwait(false);
@@ -253,7 +253,7 @@ namespace MQTTnet.Server
 
                 Server.OnClientConnected(clientId);
 
-                wasCleanDisconnect = await clientSession.RunAsync(connectPacket, clientAdapter).ConfigureAwait(false);
+                await clientSession.RunAsync(connectPacket, clientAdapter).ConfigureAwait(false);
             }
             catch (OperationCanceledException)
             {
@@ -278,8 +278,6 @@ namespace MQTTnet.Server
                 {
                     DeleteSession(clientId);
                 }
-
-                Server.OnClientDisconnected(clientId, wasCleanDisconnect);
             }
         }
 

Tests/MQTTnet.Core.Tests/MqttClientTests.cs

@@ -1,15 +1,18 @@
-using System.Net.Sockets;
+using System;
+using System.Net.Sockets;
 using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using MQTTnet.Client;
+using MQTTnet.Diagnostics;
 using MQTTnet.Exceptions;
+using MQTTnet.Implementations;
+using MQTTnet.Server;
 
 namespace MQTTnet.Core.Tests
 {
     [TestClass]
     public class MqttClientTests
     {
-
         [TestMethod]
         public async Task ClientDisconnectException()
         {

Tests/MQTTnet.Core.Tests/MqttKeepAliveMonitorTests.cs

@@ -60,7 +60,7 @@ namespace MQTTnet.Core.Tests
         {
             public string ClientId { get; }
 
-            public int StopCalledCount { get; set; }
+            public int StopCalledCount { get; private set; }
 
             public void FillStatus(MqttClientSessionStatus status)
             {
@@ -77,7 +77,7 @@ namespace MQTTnet.Core.Tests
                 throw new NotSupportedException();
             }
 
-            public Task<bool> RunAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter)
+            public Task RunAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter)
             {
                 throw new NotSupportedException();
             }

Tests/MQTTnet.Core.Tests/MqttServerTests.cs

@@ -484,6 +484,54 @@ namespace MQTTnet.Core.Tests
             Assert.IsTrue(bodyIsMatching);
         }
 
+        [TestMethod]
+        public async Task MqttServer_SameClientIdConnectDisconnectEventOrder()
+        {
+            var serverAdapter = new MqttTcpServerAdapter(new MqttNetLogger().CreateChildLogger());
+            var s = new MqttFactory().CreateMqttServer(new[] { serverAdapter }, new MqttNetLogger());
+
+            var connectedClient = false;
+            var connecteCalledBeforeConnectedClients = false;
+
+            s.ClientConnected += (_, __) =>
+            {
+                connecteCalledBeforeConnectedClients |= connectedClient;
+                connectedClient = true;
+            };
+
+            s.ClientDisconnected += (_, __) =>
+            {
+                connectedClient = false;
+            };
+
+            var clientOptions = new MqttClientOptionsBuilder()
+                .WithTcpServer("localhost")
+                .WithClientId(Guid.NewGuid().ToString())
+                .Build();
+
+            await s.StartAsync(new MqttServerOptions());
+
+            var c1 = new MqttFactory().CreateMqttClient();
+            var c2 = new MqttFactory().CreateMqttClient();
+
+            await c1.ConnectAsync(clientOptions);
+
+            await Task.Delay(100);
+
+            await c2.ConnectAsync(clientOptions);
+
+            await Task.Delay(100);
+
+            await c1.DisconnectAsync();
+            await c2.DisconnectAsync();
+
+            await s.StopAsync();
+
+            await Task.Delay(100);
+
+            Assert.IsFalse(connecteCalledBeforeConnectedClients, "ClientConnected was called before ClientDisconnect was called");
+        }
+
         private class TestStorage : IMqttServerStorage
         {
             public IList<MqttApplicationMessage> Messages = new List<MqttApplicationMessage>();