Fix rabbit_priority_queue:update_rates bug (#11814) (#11819)

updates_rates fails after publishing a message to a queue
with priorities enabled.

(cherry picked from commit ae41f65)

Co-authored-by: Michal Kuratczyk <[email protected]>

Author: mergify[bot]

deps/rabbit/src/rabbit_priority_queue.erl

@@ -329,7 +329,7 @@ depth(#passthrough{bq = BQ, bqs = BQS}) ->
     BQ:depth(BQS).
 
 update_rates(State = #state{bq = BQ}) ->
-    fold_min2(fun (_P, BQSN) -> BQ:update_rates(BQSN) end, State);
+    foreach1(fun (_P, BQSN) -> BQ:update_rates(BQSN) end, State);
 update_rates(State = #passthrough{bq = BQ, bqs = BQS}) ->
     ?passthrough1(update_rates(BQS)).
 
@@ -490,13 +490,6 @@ fold_add2(Fun, State) ->
                   {add_maybe_infinity(Res, Acc), BQSN1}
           end, 0, State).
 
-%% Fold over results assuming results are numbers and we want the minimum
-fold_min2(Fun, State) ->
-    fold2(fun (P, BQSN, Acc) ->
-                  {Res, BQSN1} = Fun(P, BQSN),
-                  {erlang:min(Res, Acc), BQSN1}
-          end, infinity, State).
-
 %% Fold over results assuming results are lists and we want to append
 %% them, and also that we have some AckTags we want to pass in to each
 %% invocation.

deps/rabbit/test/priority_queue_SUITE.erl

@@ -40,7 +40,8 @@ groups() ->
                          invoke,
                          gen_server2_stats,
                          negative_max_priorities,
-                         max_priorities_above_hard_limit
+                         max_priorities_above_hard_limit,
+                         update_rates
                         ]}
     ].
 
@@ -473,6 +474,24 @@ unknown_info_key(Config) ->
     rabbit_ct_client_helpers:close_connection(Conn),
     passed.
 
+update_rates(Config) ->
+    Node = rabbit_ct_broker_helpers:get_node_config(Config, 0, nodename),
+    {Conn, Ch} = rabbit_ct_client_helpers:open_connection_and_channel(Config, 0),
+    Q = <<"update_rates-queue">>,
+    declare(Ch, Q, [{<<"x-max-priority">>, byte, 3}]),
+    QPid = queue_pid(Config, Node, rabbit_misc:r(<<"/">>, queue, Q)),
+    try
+        publish1(Ch, Q, 1),
+        QPid ! update_rates,
+        State = get_state(Config, Q),
+        ?assertEqual(live, State),
+        delete(Ch, Q)
+    after
+        rabbit_ct_client_helpers:close_channel(Ch),
+        rabbit_ct_client_helpers:close_connection(Conn),
+        passed
+    end.
+
 %%----------------------------------------------------------------------------
 
 declare(Ch, Q, Args) when is_list(Args) ->
@@ -590,4 +609,14 @@ info(Config, Q, InfoKeys) ->
              Config, Nodename,
              rabbit_classic_queue, info, [Amq, InfoKeys]),
     {ok, Info}.
+
+get_state(Config, Q) ->
+    Nodename = rabbit_ct_broker_helpers:get_node_config(Config, 0, nodename),
+    {ok, Amq} = rabbit_ct_broker_helpers:rpc(
+                  Config, Nodename,
+                  rabbit_amqqueue, lookup, [rabbit_misc:r(<<"/">>, queue, Q)]),
+    rabbit_ct_broker_helpers:rpc(
+      Config, Nodename,
+      amqqueue, get_state, [Amq]).
+
 %%----------------------------------------------------------------------------