Question

Note: I am not using ARC

I have a UILabel with the following property: @property (nonatomic, retain) UILabel *someLabel; I am trying to set a custom setter. Would the following code cause a leak, since @property is actually calling retain as well?

- (void)setSomeLabel:(UILabel *)someLabel
{
    if (someLabel != self.someLabel) {
        [self.someLabel release];
        self.someLabel = [someLabel retain];
    }

    // some custom code here
}

Answer 1

Note: I am not using ARC

You really, really should.

---

Your setter is an infinite loop. The call to self.someLabel = ... is the exact equivalent of [self setSomeLabel:...], which causes the loop.

A correct manual setter looks like this:

- (void)setSomeLabel:(UILabel *)someLabel
{
  [someLabel retain];
  [_someLabel release];
  _someLabel = someLabel;

  // some custom code here
}

There are other common patterns. A major question is whether “some custom code” should run if the object is reset to the same value. If not, then this pattern makes more sense:

- (void)setSomeLabel:(UILabel *)someLabel
{
  if (someLabel != _someLabel) {
    [_someLabel release];
    _someLabel = [someLabel retain];

    // some custom code here
  }
}