In every action by the creditor, which must be against the principal debtor alone, except in the cases mentioned in article 2059, the former shall ask the court to notify the guarantor of the action. The guarantor may appear so that he may, if he so desire, set up such defenses as are granted him by law. The benefit of excussion mentioned in article 2058 shall always be unimpaired, even if judgment should be rendered against the principal debtor and the guarantor in case of appearance by the latter. (1834a)