fix(message_validation): take `enable` into account

apps/emqx_message_validation/src/emqx_message_validation_registry.erl

@@ -153,24 +153,26 @@ do_reindex_positions(Validations) ->
 
 do_insert(Pos, Validation) ->
     #{
+        enable := Enabled,
         name := Name,
         topics := Topics
     } = Validation,
     maybe_create_metrics(Name),
     do_insert_into_tab(Name, Validation, Pos),
-    update_topic_index(Name, Pos, Topics),
+    Enabled andalso update_topic_index(Name, Pos, Topics),
     ok.
 
 do_update(OldValidation, Pos, NewValidation) ->
     #{topics := OldTopics} = OldValidation,
     #{
+        enable := Enabled,
         name := Name,
         topics := NewTopics
     } = NewValidation,
     maybe_create_metrics(Name),
     do_insert_into_tab(Name, NewValidation, Pos),
     delete_topic_index(Name, OldTopics),
-    update_topic_index(Name, Pos, NewTopics),
+    Enabled andalso update_topic_index(Name, Pos, NewTopics),
     ok.
 
 do_delete(Validation) ->

apps/emqx_message_validation/test/emqx_message_validation_http_api_SUITE.erl

@@ -508,6 +508,42 @@ t_reorder(_Config) ->
 
     ok.
 
+t_enable_disable_via_update(_Config) ->
+    Topic = <<"t">>,
+
+    Name1 = <<"foo">>,
+    AlwaysFailCheck = sql_check(<<"select * where false">>),
+    Validation1 = validation(Name1, [AlwaysFailCheck], #{<<"topics">> => Topic}),
+
+    {201, _} = insert(Validation1#{<<"enable">> => false}),
+    ?assertIndexOrder([], Topic),
+
+    C = connect(<<"c1">>),
+    {ok, _, [_]} = emqtt:subscribe(C, Topic),
+
+    ok = publish(C, Topic, #{}),
+    ?assertReceive({publish, _}),
+
+    {200, _} = update(Validation1#{<<"enable">> => true}),
+    ?assertIndexOrder([Name1], Topic),
+
+    ok = publish(C, Topic, #{}),
+    ?assertNotReceive({publish, _}),
+
+    {200, _} = update(Validation1#{<<"enable">> => false}),
+    ?assertIndexOrder([], Topic),
+
+    ok = publish(C, Topic, #{}),
+    ?assertReceive({publish, _}),
+
+    %% Test index after delete; ensure it's in the index before
+    {200, _} = update(Validation1#{<<"enable">> => true}),
+    ?assertIndexOrder([Name1], Topic),
+    {204, _} = delete(Name1),
+    ?assertIndexOrder([], Topic),
+
+    ok.
+
 %% Check the `all_pass' strategy
 t_all_pass(_Config) ->
     Name1 = <<"foo">>,