Fix memory leak when using mandatory flag in CQs

deps/rabbit/src/rabbit_classic_queue.erl

@@ -301,9 +301,9 @@ settlement_action(Type, QRef, MsgSeqs, Acc) ->
 deliver(Qs0, #delivery{flow = Flow,
                        msg_seq_no = MsgNo,
                        message = #basic_message{exchange_name = _Ex},
-                       confirm = _Confirm} = Delivery) ->
+                       confirm = Confirm} = Delivery) ->
     %% TODO: record master and slaves for confirm processing
-    {MPids, SPids, Qs, Actions} = qpids(Qs0, MsgNo),
+    {MPids, SPids, Qs, Actions} = qpids(Qs0, Confirm, MsgNo),
     QPids = MPids ++ SPids,
     case Flow of
         %% Here we are tracking messages sent by the rabbit_channel
@@ -363,22 +363,22 @@ purge(Q) when ?is_amqqueue(Q) ->
     QPid = amqqueue:get_pid(Q),
     delegate:invoke(QPid, {gen_server2, call, [purge, infinity]}).
 
-qpids(Qs, MsgNo) ->
+qpids(Qs, Confirm, MsgNo) ->
     lists:foldl(
       fun ({Q, S0}, {MPidAcc, SPidAcc, Qs0, Actions0}) ->
               QPid = amqqueue:get_pid(Q),
               SPids = amqqueue:get_slave_pids(Q),
               QRef = amqqueue:get_name(Q),
               Actions = [{monitor, QPid, QRef}
                          | [{monitor, P, QRef} || P <- SPids]] ++ Actions0,
-              %% confirm record only if MsgNo isn't undefined
+              %% confirm record only if necessary
               S = case S0 of
                       #?STATE{unconfirmed = U0} ->
                           Rec = [QPid | SPids],
-                          U = case MsgNo of
-                                  undefined ->
+                          U = case Confirm of
+                                  false ->
                                       U0;
-                                  _ ->
+                                  true ->
                                       U0#{MsgNo => #msg_status{pending = Rec}}
                               end,
                           S0#?STATE{pid = QPid,

release-notes/3.9.8.md

@@ -0,0 +1,36 @@
+RabbitMQ `3.9.8` is a maintenance release in the `3.9.x` release series.
+
+Please refer to the **Upgrading to 3.9** section from [v3.9.0 release notes](https://github.com/rabbitmq/rabbitmq-server/releases/tag/v3.9.0) if upgrading from a version prior to 3.9.0.
+
+This release requires at least Erlang 23.2, and supports the latest Erlang 24 version, 24.1.2 at the time of release. [RabbitMQ and Erlang/OTP Compatibility Matrix](https://www.rabbitmq.com/which-erlang.html) has more details on Erlang version requirements for RabbitMQ.
+
+
+
+## Changes Worth Mentioning
+
+Release notes are kept under [rabbitmq-server/release-notes](https://github.com/rabbitmq/rabbitmq-server/tree/v3.9.x/release-notes).
+Contributors are encouraged to update them together with their changes. This helps with release automation and a more consistent release schedule.
+
+### Core Server
+
+#### Enhancements
+
+ * ...
+
+
+#### Bug Fixes
+
+* When the mandatory flag was used when publishing to classic queues,
+  but publisher confirms were not, channels memory usage would grow indefinitely.
+
+   GitHub issue: [#3560](https://github.com/rabbitmq/rabbitmq-server/issues/3560)
+
+
+## Dependency Upgrades
+
+ * ...
+
+
+## Source Code Archives
+
+To obtain source code of the entire distribution, please download the archive named `rabbitmq-server-3.9.8.tar.xz` instead of the source tarball produced by GitHub.