* Add CurrentQueue to IModel to keep track of the last declared queue name as defined in the AMQP 091 spec

* Fix `RecordedConsumer` to use `CurrentQueue` when passed in name is `string.Empty`

Author: lukebakken

projects/RabbitMQ.Client/client/api/IModel.cs

@@ -97,6 +97,14 @@ public interface IModel : IDisposable
         /// </summary>
         ulong NextPublishSeqNo { get; }
 
+        /// <summary>
+        /// The name of the last queue declared on this channel.
+        /// </summary>
+        /// <remarks>
+        /// https://www.rabbitmq.com/amqp-0-9-1-reference.html#domain.queue-name
+        /// </remarks>
+        string CurrentQueue { get; }
+
         /// <summary>
         /// Signalled when a Basic.Ack command arrives from the broker.
         /// </summary>

projects/RabbitMQ.Client/client/impl/AutorecoveringModel.cs

@@ -395,6 +395,19 @@ public ulong NextPublishSeqNo
             }
         }
 
+        public string CurrentQueue
+        {
+            get
+            {
+                if (_disposed)
+                {
+                    throw new ObjectDisposedException(GetType().FullName);
+                }
+
+                return _delegate.CurrentQueue;
+            }
+        }
+
         public void AutomaticallyRecover(AutorecoveringConnection conn, bool recoverConsumers)
         {
             if (_disposed)

projects/RabbitMQ.Client/client/impl/ModelBase.cs

@@ -170,6 +170,8 @@ public bool IsOpen
 
         public ulong NextPublishSeqNo { get; private set; }
 
+        public string CurrentQueue { get; private set; }
+
         public ISession Session { get; private set; }
 
         public Task Close(ushort replyCode, string replyText, bool abort)
@@ -1481,7 +1483,9 @@ private QueueDeclareOk QueueDeclare(string queue, bool passive, bool durable, bo
                 _Private_QueueDeclare(queue, passive, durable, exclusive, autoDelete, false, arguments);
                 k.GetReply(ContinuationTimeout);
             }
-            return k.m_result;
+            QueueDeclareOk result = k.m_result;
+            CurrentQueue = result.QueueName;
+            return result;
         }
 
 

projects/RabbitMQ.Client/client/impl/RecordedConsumer.cs

@@ -47,17 +47,20 @@ public RecordedConsumer(AutorecoveringModel model, string queue, string consumer
                 Model = model;
             }
 
-            /*
-             * NB: queue can be the empty string in the case of server-named queues
-             * https://github.com/rabbitmq/rabbitmq-dotnet-client/issues/1238
-             */
             if (queue is null)
             {
                 throw new ArgumentNullException(nameof(queue));
             }
             else
             {
-                Queue = queue;
+                if (queue == string.Empty)
+                {
+                    Queue = model.CurrentQueue;
+                }
+                else
+                {
+                    Queue = queue;
+                }
             }
 
             if (string.IsNullOrEmpty(consumerTag))
@@ -80,7 +83,14 @@ public RecordedConsumer(AutorecoveringModel model, string queue, string consumer
 
         public string Recover(IModel channelToUse)
         {
-            ConsumerTag = channelToUse.BasicConsume(Queue, AutoAck,
+            string queueName = Queue;
+            if (string.IsNullOrEmpty(queueName))
+            {
+                // https://www.rabbitmq.com/amqp-0-9-1-reference.html#domain.queue-name
+                queueName = channelToUse.CurrentQueue;
+            }
+
+            ConsumerTag = channelToUse.BasicConsume(queueName, AutoAck,
                 ConsumerTag, false, Exclusive,
                 Arguments, Consumer);
 

projects/Unit/TestConnectionRecovery.cs

@@ -424,12 +424,21 @@ public void TestConsumerRecoveryWithServerNamedQueue()
                 m.BasicConsume(string.Empty, true, cons);
                 AssertConsumerCount(m, qname, 1);
 
+                bool queueNameBeforeIsEqual = false;
                 bool queueNameChangeAfterRecoveryCalled = false;
-                c.QueueNameChangeAfterRecovery += (source, ea) => { queueNameChangeAfterRecoveryCalled = true; };
+                string qnameAfterRecovery = null;
+                c.QueueNameChangeAfterRecovery += (source, ea) =>
+                {
+                    queueNameChangeAfterRecoveryCalled = true;
+                    queueNameBeforeIsEqual = qname.Equals(ea.NameBefore);
+                    qnameAfterRecovery = ea.NameAfter;
+                };
 
                 CloseAndWaitForRecovery(c);
-                AssertConsumerCount(m, qname, 1);
+
+                AssertConsumerCount(m, qnameAfterRecovery, 1);
                 Assert.True(queueNameChangeAfterRecoveryCalled);
+                Assert.True(queueNameBeforeIsEqual);
             }
         }