There's a possibility that rabbit has to be able to be started without being booted. Thus we need to be able to load the transitive closure of rabbit's dependencies on demand. This is especially needed for the tests.

1 files changed, 25 insertions, 0 deletions

diff --git a/src/rabbit.erl b/src/rabbit.erl
index 0d163944..5ec0611a 100644
--- a/src/rabbit.erl
+++ b/src/rabbit.erl
@@ -390,7 +390,32 @@ config_files() ->
 
 %%---------------------------------------------------------------------------
 
+load_applications() ->
+    load_applications(queue:from_list(?APPS), sets:new()).
+
+load_applications(Worklist, Loaded) ->
+    case queue:out(Worklist) of
+        {empty, _WorkList} ->
+            ok;
+        {{value, App}, Worklist1} ->
+            case sets:is_element(App, Loaded) of
+                true  -> load_applications(Worklist1, Loaded);
+                false -> case application:load(App) of
+                             ok                             -> ok;
+                             {error, {already_loaded, App}} -> ok;
+                             Error                          -> throw(Error)
+                         end,
+                         load_applications(
+                           case application:get_key(App, applications) of
+                               undefined -> Worklist1;
+                               {ok, Lst} -> queue:join(Worklist1,
+                                                       queue:from_list(Lst))
+                           end, sets:add_element(App, Loaded))
+            end
+    end.
+
 application_load_order() ->
+    ok = load_applications(),
     {ok, G} = rabbit_misc:build_acyclic_graph(
                 fun application_graph_vertex/2, fun application_graph_edge/2,
                 [{App, case application:get_key(App, applications) of