ObjFW  View Ticket

The Apple runtime seems to make some assumptions about root objects being NSObject, and as a result segfaults when using weak.

Looking at the code, it seems that objc_destructInstance() does not zero weak references at all in the Apple runtime. It seems to make weak references work at all, it is necessary to call into the runtime functions to allocate, retain, release and dealloc objects. Unfortunately, this does not allow to have some extra space before the object, as the current +[alloc] does for memory blocks belonging to the object.

Turns out the configure check for objc_constructInstance was broken, and hence runtime/instance.m was used for objc_destructInstance instead of the runtime's, resulting in weak references not being handled on dealloc.

Fixed in 4c16806252.