I am attempting to debug an issue where an object is released too many times and is then deallocated by the event loop. The next time I try to read from the object, the application crashes with EXC_BAD_ACCESS.
To debug, I am enabling NSZombies and then using the Zombies profile with Instruments. I then reach the point where my app crashes and Instruments informs me about a message being sent to a deallocated instance. So far, so good.
It does a very good job of showing me where libraries such as UIKit are releasing and retaining the pointer to my object, but it does not show me where my own code is doing this. It is also not displaying the true reference count. By the time that Instruments says that the reference count is 1, the reference count is actually 8 according to printing out the reference count in gdb.
I have investigated the possibility that Instruments is somehow filtering the output but it would appear that I really am recording every release and retain event. It absolutely must be something in my application because my view controller is instantly deallocated after displaying, meaning that attempting to do anything that would send a message to the controller would crash it.
After placing a breakpoint in the dealloc method, I found that my object is indeed being deallocated by the event loop, so this is not a case of a rogue call to dealloc by something else.
You can’t rely on reference count as Apple’s Framework classes may hold their own references to your objects. The reference count is meaningless for debugging.