Fix schema default for array path exprs

src/gmconfig.erl

@@ -101,7 +101,7 @@ mock_config() ->
 
 mock_config(Cfg) ->
     ensure_schema_loaded(),
-    store(Cfg, Mode = silent).
+    store(Cfg, _Mode = silent).
 
 unmock_config() ->
     gmconfig_schema_utils:clear(),
@@ -445,7 +445,20 @@ just_schema_keys(_) ->
 schema_default(Path) when is_list(Path) ->
     schema_default(Path, schema()).
 
-schema_default(Path, Schema) ->
+schema_default(Path0, Schema) ->
+    %% There is a way to navigate through an array of objects
+    %% essentially locating the desired object in the array, and then
+    %% continuing into one of its properties. This is specified in
+    %% a path exression as `{PropName, Value, ThenProp}`.
+    %% If the query expects us to fall back to the schema default, then
+    %% we must adapt the path accordingly.
+    %%
+    %% find_config([<<"system">>, <<"plugins">>,
+    %%              {<<"name">>, PluginName, <<"config">>} | Key],
+    %%             [user_config, schema_default]);
+    Path = lists:flatmap(fun({_, _,P}) -> [<<"items">>, P];
+                            (P) -> [P]
+                         end, Path0),
     case schema(Path, Schema) of
         undefined -> undefined;
         {ok, Tree} ->