Dont allow QQ grow for target quorum cluster size less than 0 in rabbit_quorum_queue api

Author: Ayanda-D

deps/rabbit/src/rabbit_quorum_queue.erl

@@ -1569,7 +1569,7 @@ grow(Node, VhostSpec, QueueSpec, Strategy, Membership) when is_atom(Node) ->
         is_match(get_resource_name(amqqueue:get_name(Q)), QueueSpec) ];
 
 grow(QuorumClusterSize, VhostSpec, QueueSpec, Strategy, Membership)
-  when is_integer(QuorumClusterSize) ->
+  when is_integer(QuorumClusterSize), QuorumClusterSize > 0 ->
     Running = rabbit_nodes:list_running(),
     TotalRunning = length(Running),
 
@@ -1598,7 +1598,14 @@ grow(QuorumClusterSize, VhostSpec, QueueSpec, Strategy, Membership)
             amqqueue:get_type(Q) == ?MODULE,
             matches_strategy(Strategy, get_nodes(Q)),
             is_match(amqqueue:get_vhost(Q), VhostSpec) andalso
-            is_match(get_resource_name(amqqueue:get_name(Q)), QueueSpec)]).
+            is_match(get_resource_name(amqqueue:get_name(Q)), QueueSpec)]);
+
+grow(QuorumClusterSize, _VhostSpec, _QueueSpec, _Strategy, _Membership)
+  when is_integer(QuorumClusterSize) ->
+    rabbit_log:warning(
+            "cannot grow queues to a quorum cluster size less than zero (~tp)",
+            [QuorumClusterSize]),
+    {error, bad_quorum_cluster_size}.
 
 maybe_grow(Q, Node, Membership, Size) ->
     QName = amqqueue:get_name(Q),

deps/rabbit/test/quorum_queue_SUITE.erl

@@ -1845,13 +1845,22 @@ grow_queue(Config) ->
     %% shrink all queues again
     rabbit_ct_broker_helpers:rpc(Config, 0, rabbit_quorum_queue,
         force_all_queues_shrink_member_to_current_member, []),
-
     assert_grown_queues(QQs, Server0, TargetClusterSize_1, MsgCount),
 
     %% grow queues to quorum cluster size > '5' (limit = 5).
     TargetClusterSize_10 = 10,
     rpc:call(Server0, rabbit_quorum_queue, grow, [TargetClusterSize_10, <<"/">>, <<".*">>, all]),
-    assert_grown_queues(QQs, Server0, TargetClusterSize_5, MsgCount).
+    assert_grown_queues(QQs, Server0, TargetClusterSize_5, MsgCount),
+
+    %% shrink all queues again
+    rabbit_ct_broker_helpers:rpc(Config, 0, rabbit_quorum_queue,
+        force_all_queues_shrink_member_to_current_member, []),
+    assert_grown_queues(QQs, Server0, TargetClusterSize_1, MsgCount),
+
+    %% attempt to grow queues to quorum cluster size < '0'.
+    BadTargetClusterSize = -5,
+    ?assertEqual({error, bad_quorum_cluster_size},
+        rpc:call(Server0, rabbit_quorum_queue, grow, [BadTargetClusterSize, <<"/">>, <<".*">>, all])).
 
 assert_grown_queues(Qs, Node, TargetClusterSize, MsgCount) ->
     [begin