No longer fire _ClientAcknowledgedPublishPacketEvent_ for PUBREC packets (#1550)

.github/workflows/ReleaseNotes.md

@@ -0,0 +1 @@
+* [Server] Fixed duplicated invocation of the event _ClientAcknowledgedPublishPacketAsync_ for QoS level 2 (#1550)

MQTTnet.sln.DotSettings

@@ -242,5 +242,6 @@ See the LICENSE file in the project root for more information.</s:String>
 	<s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EPsi_002ECSharp_002ECodeStyle_002ESettingsUpgrade_002EMigrateThisQualifierSettings/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=PINGREQ/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=PINGRESP/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=PUBCOMP/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Tnet/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=unsub/@EntryIndexedValue">True</s:Boolean></wpf:ResourceDictionary>

Source/MQTTnet.Tests/Server/QoS_Tests.cs

@@ -99,25 +99,16 @@ public async Task Fire_Event_On_Client_Acknowledges_QoS_2()
 
                 await LongTestDelay();
 
-                Assert.AreEqual(2, eventArgs.Count);
+                Assert.AreEqual(1, eventArgs.Count);
 
                 var firstEvent = eventArgs[0];
 
                 Assert.IsNotNull(firstEvent);
                 Assert.IsNotNull(firstEvent.PublishPacket);
                 Assert.IsNotNull(firstEvent.AcknowledgePacket);
-                Assert.IsFalse(firstEvent.IsCompleted);
+                Assert.IsTrue(firstEvent.IsCompleted);
 
                 Assert.AreEqual("A", firstEvent.PublishPacket.Topic);
-
-                var secondEvent = eventArgs[1];
-
-                Assert.IsNotNull(secondEvent);
-                Assert.IsNotNull(secondEvent.PublishPacket);
-                Assert.IsNotNull(secondEvent.AcknowledgePacket);
-                Assert.IsTrue(secondEvent.IsCompleted);
-
-                Assert.AreEqual("A", secondEvent.PublishPacket.Topic);
             }
         }
     }

Source/MQTTnet/Server/Events/ClientAcknowledgedPublishPacketEventArgs.cs

@@ -10,15 +10,23 @@ namespace MQTTnet.Server
 {
     public sealed class ClientAcknowledgedPublishPacketEventArgs : EventArgs
     {
+        public ClientAcknowledgedPublishPacketEventArgs(string clientId, IDictionary sessionItems, MqttPublishPacket publishPacket, MqttPacketWithIdentifier acknowledgePacket)
+        {
+            ClientId = clientId ?? throw new ArgumentNullException(nameof(clientId));
+            SessionItems = sessionItems ?? throw new ArgumentNullException(nameof(sessionItems));
+            PublishPacket = publishPacket ?? throw new ArgumentNullException(nameof(publishPacket));
+            AcknowledgePacket = acknowledgePacket ?? throw new ArgumentNullException(nameof(acknowledgePacket));
+        }
+
         /// <summary>
         ///     Gets the packet which was used for acknowledge. This can be a PubAck or PubComp packet.
         /// </summary>
-        public MqttPacketWithIdentifier AcknowledgePacket { get; internal set; }
+        public MqttPacketWithIdentifier AcknowledgePacket { get; }
 
         /// <summary>
         ///     Gets the ID of the client which acknowledged a PUBLISH packet.
         /// </summary>
-        public string ClientId { get; internal set; }
+        public string ClientId { get; }
 
         /// <summary>
         ///     Gets whether the PUBLISH packet is fully acknowledged. This is the case for PUBACK (QoS 1) and PUBCOMP (QoS 2.
@@ -28,11 +36,11 @@ public sealed class ClientAcknowledgedPublishPacketEventArgs : EventArgs
         /// <summary>
         ///     Gets the PUBLISH packet which was acknowledged.
         /// </summary>
-        public MqttPublishPacket PublishPacket { get; internal set; }
+        public MqttPublishPacket PublishPacket { get; }
 
         /// <summary>
         ///     Gets the session items which contain custom user data per session.
         /// </summary>
-        public IDictionary SessionItems { get; internal set; }
+        public IDictionary SessionItems { get; }
     }
 }

Source/MQTTnet/Server/Internal/MqttClient.cs

@@ -11,7 +11,6 @@
 using MQTTnet.Diagnostics;
 using MQTTnet.Exceptions;
 using MQTTnet.Formatter;
-using MQTTnet.Implementations;
 using MQTTnet.Internal;
 using MQTTnet.PacketDispatcher;
 using MQTTnet.Packets;
@@ -170,14 +169,7 @@ Task ClientAcknowledgedPublishPacket(MqttPublishPacket publishPacket, MqttPacket
         {
             if (_eventContainer.ClientAcknowledgedPublishPacketEvent.HasHandlers)
             {
-                var eventArgs = new ClientAcknowledgedPublishPacketEventArgs
-                {
-                    PublishPacket = publishPacket,
-                    AcknowledgePacket = acknowledgePacket,
-                    ClientId = Id,
-                    SessionItems = Session.Items
-                };
-
+                var eventArgs = new ClientAcknowledgedPublishPacketEventArgs(Id, Session.Items, publishPacket, acknowledgePacket);
                 return _eventContainer.ClientAcknowledgedPublishPacketEvent.TryInvokeAsync(eventArgs, _logger);
             }
 
@@ -272,17 +264,14 @@ async Task HandleIncomingPublishPacket(MqttPublishPacket publishPacket, Cancella
             }
         }
 
-        async Task HandleIncomingPubRecPacket(MqttPubRecPacket pubRecPacket)
+        Task HandleIncomingPubRecPacket(MqttPubRecPacket pubRecPacket)
         {
-            var acknowledgedPublishPacket = Session.PeekAcknowledgePublishPacket(pubRecPacket.PacketIdentifier);
-
-            if (acknowledgedPublishPacket != null)
-            {
-                await ClientAcknowledgedPublishPacket(acknowledgedPublishPacket, pubRecPacket).ConfigureAwait(false);
-            }
-
+            // Do not fire the event _ClientAcknowledgedPublishPacket_ here because the QoS 2 process is only finished
+            // properly when the client has sent the PUBCOMP packet.
             var pubRelPacket = _packetFactories.PubRel.Create(pubRecPacket, MqttApplicationMessageReceivedReasonCode.Success);
             Session.EnqueueControlPacket(new MqttPacketBusItem(pubRelPacket));
+
+            return CompletedTask.Instance;
         }
 
         void HandleIncomingPubRelPacket(MqttPubRelPacket pubRelPacket)