When your filter finds no result, what does it return? Does it return a null value, an empty string, a json document describing the fact that there were no results found? If I were to run r\table('users')->filter(array('user_name' => $user_name))->run($this->r)
and there were no users found by that name, what would Rethink return?
I can't seem to find this on the extended docs for filter or the regular API documentation.