list_unresponsive_queues crashes if a QoS 0 queue used by an MQTT client is present

[gomoripeti]

Describe the bug

RabbitMQ 3.13.x or main at b4efe04

The command rabbitmqctl list_unresponsive_queues crashes with a function clause if there is a queue of type :rabbit_mqtt_qos0_queue present. This is because rabbit_amqqueue:is_unresponsive/2 only expects the 3 known queue types (

rabbitmq-server/deps/rabbit/src/rabbit_amqqueue.erl

Line 1315 in fde9950

is_unresponsive(Q, _Timeout) when ?amqqueue_state_is(Q, crashed) ->

)

Reproduction steps

1. With a 3.13.x RabbitMQ version eg 3.13.3 enable the rabbitmq_mqtt plugin
2. Enabe feature flag rabbit_mqtt_qos0_queue
3. Create an MQTT connection and subscribe with QoS0 for example using emqtt client

   Options = [{host, "localhost"},
              {port, 1883},
              {ssl, false},
              {clientid, <<"guest">>},
              {username, <<"guest">>},
              {password, <<"guest">>}
             ],
   {ok, Conn} = emqtt:start_link(Options),
   {ok, _Props} = emqtt:connect(Conn),
   {ok, _, _} = emqtt:subscribe(Conn, <<"topic">>, qos0).

4. Try to list unresponsive queues

   # sbin/rabbitmqctl list_unresponsive_queues
   Listing unresponsive queues for vhost / ...
   {:badrpc, {:EXIT, {:function_clause, [{:rabbit_amqqueue, :is_unresponsive, [{:amqqueue, {:resource, "/", :queue, "mqtt-subscription-guestqos0"}, true, false, #PID<13145.10121.0>, [], #PID<13145.10121.0>, [], [], [], :undefined, :undefined, [], [], :live, 0, [], "/", %{user: "guest"}, :rabbit_mqtt_qos0_queue, %{}}, 15000], [file: 'rabbit_amqqueue.erl', line: 1315]}, {:rabbit_amqqueue, :"-emit_unresponsive_local/5-fun-0-", 3, [file: 'rabbit_amqqueue.erl', line: 1421]}, {:rabbit_misc, :with_exit_handler, 2, [file: 'rabbit_misc.erl', line: 525]}, {:rabbit_control_misc, :step_with_exit_handler, 4, [file: 'rabbit_control_misc.erl', line: 58]}, {:rabbit_control_misc, :"-emitting_map0/5-lc$^0/1-0-", 5, [file: 'rabbit_control_misc.erl', line: 50]}, {:rabbit_control_misc, :emitting_map_with_exit_handler, 5, [file: 'rabbit_control_misc.erl', line: 46]}, {:rabbit_control_misc, :emitting_map_with_exit_handler, 4, [file: 'rabbit_control_misc.erl', line: 41]}]}}}

Expected behavior

Successfully return an empty list.

In more general terms Im not sure what should be returned for 3rd party custom queue types. The code could either always ignore queue types which are not classic, quorum or stream. Or there needs to be an optional callback of the queue type that returns if the queue is unresponsive.

Additional context

No response

[gomoripeti]

thanks for promptly addressing this issue