Question

I’m just updating an app of mine, and I found some old code that raised my eyebrows. My commenting is normally pretty verbose but I didn’t explain to myself why I did this.

I’m presenting a ModalView and updating the title and UITextField, like so:

addStoryItem.placeholderText = @"Foo"; //The text is always a static string.
addStoryItem.modalTitleText  = @"Bar";

In the modal, the properties are assigned for both of these values:

@property (readwrite, assign) NSString *placeholderText;
@property (readwrite, assign) NSString *modalTitleText;

And then released in the modal’s dealloc after the modal is dismissed:

[placeholderText release];
[modalTitleText  release];

Is this safe/wise/ok? I think I might have done this to avoid a retain cycle.

Answer 1

You broke a couple of rules:

1. Release what you own. (You don’t own assign properties. You just got away with it because releasing string literals is a nop)
2. Always copy NSString properties. (Assign is really dangerous here, the object might just go away. Again, not for literals.)

You justify this with avoiding retain cycles. But since strings do not (usually) refer to other objects, cycles are not an issue here.