In Atherley v. MacDonald, Young & Nelson (1955) 135 Cal.App.2d 383, appellants and respondent were joined as codefendants in an action for personal injuries sustained by plaintiff in a fall on a steel stairway under construction. Appellants filed a cross-complaint against respondent alleging that he had agreed to hold them harmless from any liability caused by his negligence in constructing the stairway. The cross-complaint sought a declaratory judgment establishing the rights and liabilities of the parties under this contract. The trial court sustained respondent's demurrer to the cross-complaint without leave to amend. Pending appeal from dismissal of the cross-complaint, the main action was tried resulting in a judgment for plaintiff against appellants and a judgment in favor of respondent. Respondent argued that the appeal had become moot because of the judgment entered in his favor on the complaint. The court rejected the contention, stating: ". . . in no event is a judgment in an action in which the parties were not adversaries, but only joined as codefendants, res judicata as between them in a later proceeding." (135 Cal.App.2d at p. 385.)