Code of Civil Procedure, 1908
No decree shall be reversed or substantially varied, nor shall any case be remanded, in appeal on account of any misjoinder [or non-joinder] of parties or causes of action or any error, defect or irregularity in any proceedings in the suit, not affecting the merits of the case or the jurisdiction of the Court: [Provided that nothing in this section shall apply to non-joinder of a necessary party.]