Why are UIKit delegates "assign"ed instead of "weak"?

Question

As the title states, why are `UIKit` delegates `(assign)` instead of `(weak)`? See `UIPopovercontroller.h` for example: `@property (nonatomic, assign) id <UIPopoverControllerDelegate> delegate;` As far as I can tell this provides no benefits over a weakly retained property but a lot of problems where the delegate needs to manage it's own lifetime as a delegate. It this a backwards compatibility issue? Thanks

Accepted Answer

Because most of those properties existed before the iOS SDK supported weak properties. The `weak` attribute is only supported on iOS 5.0 and later.

I would have to guess that once iOS 4.x and earlier is history, they will all be updated to `weak`.

Why are UIKit delegates "assign"ed instead of "weak"?

Solution

Problem