What is the effect of a judgment against a co-contractor being set aside?

Mr. Justice Cartwright wrote a concurring judgment at page 648 he said: ... As to this if the matter were devoid of authority I would have thought that upon the judgment against one of several co-contractors being set aside it would cease to operate as a bar to an action against the others, that upon being set aside it ceases to exist and therefore to have any effect thereafter, although it could in some circumstances provide a justification for an act done in reliance upon it between the time of its being given and being set aside, as for example in the case of Williams v. Smith (1863), 14 C.B.N.S. 596. (emphasis added)