Set delivery-count in 1st FLOW to client

"In the event that the receiving link endpoint has not yet seen the
initial attach frame from the sender this field MUST NOT be set."
[2.7.4]

Since we (the server / the receiving link endpoint), have already seen
the initial attach frame from the sender, set the delivery-count.

Author: ansd

deps/rabbit/src/rabbit_amqp_session.erl

@@ -79,7 +79,7 @@
           %% queue_name_bin is only set if the link target address refers to a queue.
           queue_name_bin :: undefined | rabbit_misc:resource_name(),
           delivery_count :: sequence_no(),
-          credit = 0 :: non_neg_integer(),
+          credit :: non_neg_integer(),
           %% TRANSFER delivery IDs published to queues but not yet confirmed by queues
           incoming_unconfirmed_map = #{} :: #{delivery_number() =>
                                               {#{rabbit_amqqueue:name() := ok},
@@ -707,7 +707,8 @@ handle_control(#'v1_0.attach'{role = ?SEND_ROLE,
                               source = Source,
                               snd_settle_mode = SndSettleMode,
                               target = Target,
-                              initial_delivery_count = ?UINT(DeliveryCount)} = Attach,
+                              initial_delivery_count = DeliveryCount = ?UINT(DeliveryCountInt)
+                             } = Attach,
                State0 = #state{incoming_links = IncomingLinks0,
                                cfg = #cfg{vhost = Vhost,
                                           user = User}}) ->
@@ -718,7 +719,7 @@ handle_control(#'v1_0.attach'{role = ?SEND_ROLE,
                               exchange = XName,
                               routing_key = RoutingKey,
                               queue_name_bin = QNameBin,
-                              delivery_count = DeliveryCount,
+                              delivery_count = DeliveryCountInt,
                               credit = ?LINK_CREDIT_RCV},
             _Outcomes = outcomes(Source),
             OutputHandle = output_handle(InputHandle),
@@ -731,14 +732,10 @@ handle_control(#'v1_0.attach'{role = ?SEND_ROLE,
                        target = Target,
                        %% We are the receiver.
                        role = ?RECV_ROLE,
-                       %% "ignored if the role is receiver"
-                       initial_delivery_count = undefined,
                        max_message_size = {ulong, persistent_term:get(max_message_size)}},
-            Flow = #'v1_0.flow'{
-                      handle = OutputHandle,
-                      link_credit = ?UINT(?LINK_CREDIT_RCV),
-                      drain = false,
-                      echo = false},
+            Flow = #'v1_0.flow'{handle = OutputHandle,
+                                delivery_count = DeliveryCount,
+                                link_credit = ?UINT(?LINK_CREDIT_RCV)},
             %%TODO check that handle is not present in either incoming_links or outgoing_links:
             %%"The handle MUST NOT be used for other open links. An attempt to attach
             %% using a handle which is already associated with a link MUST be responded to