Also cleanup MqttClientSessionsManager._subscriberSessions when session is taken over by a new one with CleanSession=true, fix #1552 (#1553)

Author: yyjdelete

Source/MQTTnet.Tests/Internal/AsyncSignal_Tests.cs

@@ -90,7 +90,7 @@ public async Task Signal()
  Assert.IsTrue(stopwatch.ElapsedMilliseconds > 900);
  }
  }
- 
+
  [TestMethod]
  [ExpectedException(typeof(InvalidOperationException))]
  public async Task Fail_For_Two_Waiters()

Source/MQTTnet/Server/Internal/MqttClientSessionsManager.cs

@@ -485,9 +485,10 @@ async Task<MqttClient> CreateClientConnection(
  using (await _createConnectionSyncRoot.EnterAsync().ConfigureAwait(false))
  {
  MqttSession session;
+ MqttSession oldSession;
  lock (_sessionsManagementLock)
  {
- if (!_sessions.TryGetValue(connectPacket.ClientId, out session))
+ if (!_sessions.TryGetValue(connectPacket.ClientId, out oldSession))
  {
  session = CreateSession(connectPacket.ClientId, validatingConnectionEventArgs.SessionItems, sessionShouldPersist);
  }
@@ -496,11 +497,14 @@ async Task<MqttClient> CreateClientConnection(
  if (connectPacket.CleanSession)
  {
  _logger.Verbose("Deleting existing session of client '{0}' due to clean start.", connectPacket.ClientId);
+ _subscriberSessions.Remove(oldSession);
  session = CreateSession(connectPacket.ClientId, validatingConnectionEventArgs.SessionItems, sessionShouldPersist);
  }
  else
  {
  _logger.Verbose("Reusing existing session of client '{0}'.", connectPacket.ClientId);
+ session = oldSession;
+ oldSession = null;
  // Session persistence could change for MQTT 5 clients that reconnect with different SessionExpiryInterval
  session.IsPersistent = sessionShouldPersist;
  connAckPacket.IsSessionPresent = true;
@@ -533,7 +537,7 @@ async Task<MqttClient> CreateClientConnection(
  existingClient.IsTakenOver = true;
  await existingClient.StopAsync(MqttDisconnectReasonCode.SessionTakenOver).ConfigureAwait(false);
 
- if (_eventContainer.ClientConnectedEvent.HasHandlers)
+ if (_eventContainer.ClientDisconnectedEvent.HasHandlers)
  {
  var eventArgs = new ClientDisconnectedEventArgs(
  existingClient.Id,
@@ -544,6 +548,8 @@ async Task<MqttClient> CreateClientConnection(
  await _eventContainer.ClientDisconnectedEvent.InvokeAsync(eventArgs).ConfigureAwait(false);
  }
  }
+
+ oldSession?.Dispose();
  }
 
  return client;