fix(emqx_app): Dialyzer warnings

src/emqx_alarm_handler.erl

@@ -85,4 +85,4 @@ handle_call(_Query, State) ->
 terminate(swap, _State) ->
     {emqx_alarm_handler, []};
 terminate(_, _) ->
-    ok.
+    ok.

src/emqx_app.erl

@@ -34,18 +34,18 @@ start(_Type, _Args) ->
     {ok, Sup} = emqx_sup:start_link(),
     ok = emqx_modules:load(),
     ok = emqx_plugins:init(),
-    emqx_plugins:load(),
+    _ = emqx_plugins:load(),
     emqx_boot:is_enabled(listeners)
       andalso (ok = emqx_listeners:start()),
     start_autocluster(),
     register(emqx, self()),
-    emqx_alarm_handler:load(),
+    ok = emqx_alarm_handler:load(),
     print_vsn(),
     {ok, Sup}.
 
 -spec(stop(State :: term()) -> term()).
 stop(_State) ->
-    emqx_alarm_handler:unload(),
+    ok = emqx_alarm_handler:unload(),
     emqx_boot:is_enabled(listeners)
       andalso emqx_listeners:stop(),
     emqx_modules:unload().

src/emqx_plugins.erl

@@ -59,7 +59,7 @@ init() ->
     end.
 
 %% @doc Load all plugins when the broker started.
--spec(load() -> list() | {error, term()}).
+-spec(load() -> ok | ignore | {error, term()}).
 load() ->
     load_expand_plugins(),
     case emqx:get_env(plugins_loaded_file) of
@@ -103,7 +103,7 @@ unload(PluginName) when is_atom(PluginName) ->
             ?LOG(error, "Plugin ~s is not started", [PluginName]),
             {error, not_started};
         {_, _} ->
-            unload_plugin(PluginName, true)            
+            unload_plugin(PluginName, true)
     end.
 
 reload(PluginName) when is_atom(PluginName)->