Recommended way to declare delegate properties with ARC

Question

I used to declare all delegate properties as

@property (assign) id<FooDelegate> delegate;

I was under the impression that all assign properties should now be weak pointers, is this correct? If I try to declare as:

@property (weak) id<FooDelegate> delegate;

I get an error while trying to @synthesize (autogenerated weak properties are not supported).

What's the best practice in this case?

This is a good question and the answers are not very conclusive. I would have thought to use weak but the Apple frameworks use assign (see UIPageViewController which is only available on iOS5+). — Paul de Lange

djromero djromero · Accepted Answer · 2011-10-13T14:49:41

Xcode 4 Refactor > Convert to Objective-C ARC transforms:

@interface XYZ : NSObject
{
    id delegate;
}
@property (assign) id delegate;
...
@synthesize delegate;

into:

@interface XYZ : NSObject
{
    id __unsafe_unretained delegate;
}
@property (unsafe_unretained) id delegate;
...
@synthesize delegate;

If I remember correctly it is also mentioned in WWDC 2011 video about ARC.