On Wednesday, December 5, 2018 at 1:53:07 PM UTC-8, Jeroen Demeyer wrote: > > > With my idea, the domain and codomain would be treated exactly the same: > my plan is to reference the map from both the domain and codomain in a > symmetric way. In that way, the lifetime of A wouldn't depend on C the > same way that the lifetime of B or C doesn't depend on A. >
Then you DO get a memory leak as soom as UniqueRepresentation objects are involved. Let's assume that B is constructed from A. Then a strong reference to A exists because A occurs as a key in the UniqueRepresentation weakvalue dict. Because the coercion map from A to B is also stored on A, a strong reference to B exists. As long as A and B are alive, the coercion map is alive as well, so these references don't change. A really has its life time lower bounded by B. So somehow, you'd want B to be collectible under some circumstances. But then the coercion map needs to be "unreachable" as well, because it carries a strong reference to B. Conversely, as long as B is alive, A is also alive, so the coercion map must be reachable. So it seems to me B should just have a strong reference to the coercion map. Furthermore, A should not have a strong reference to the coercion map, because otherwise A and B are immortal. It doesn't look to me as if a MultiWeakRef is going to help at all with the lifetime problems here. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
