Proper property semantics for forwarding to a copied property in Objective-C

Question

Let's assume there is a UIView that contains a UILabel internally.

The UIView's public interface is as follows in it's .h:

@interface MyView : UIView

@property (nonatomic, copy) NSString *text;

@end

and privately within it's .m:

@interface MyView ()

@property (nonatomic, strong) UILabel coolLabel;

@end

with the implementation in it's .m:

@implementation

- (void)setText:(NSString *)text
{
    self.coolLabel.text = text;
}

- (NSString *)text
{
   return self.coolLabel.text;
}

@end

Looking at the public interface I declare @property (nonatomic, copy) NSString *text with a copy because the text is copied by the coolLabel internally. However, I'm not sure if this is correct.

Should the declaration be @property (nonatomic, assign) NSString *text with an assign instead because my class isn't specifically performing the memory management? Or is my current interface declared correctly?

FYI, everything assumes ARC

Answer 1

Your text property should be copy because ultimately its value is being copied by the label.

The property definition is like a contract. You are telling users of the property how the value will be treated. Since the label copies the text, you should indicate your property is being copied.