Fix no error return with IS_STRONG validator because it returns a gluon.html.XML instead of str, so when pushed to response.errors that is a Row, it isn't display because Row object filters his output and doesn't support XML objects.
Better solution than my last commit for the restful method by inject the real restful method.
We can now call LOAD() on a @request.restful() decorated action.
When you call LOAD() on a controller who has some actions decorates with @request.restful(), it fail with:
@request.restful()
TypeError: 'NoneType' object is not callable
=> because LOAD use other_request variable who are a Request but without all methods and therefore without restful method.
I've just mock the restful method but I think that the real restful method will be better...