Question

I am getting memory leak warnings for these two methods. The second one calls the first one and apparently its leaking memory. Any ideas?

static UIColor *subtreeBorderColor(void) 
{
    return [UIColor colorWithRed:0.0f green:0.5f blue:0.0f alpha:1.0f];
}


- (void) updateSubtreeBorder 
{
    CALayer *layer = [self layer];
    if (layer) {


        // If the enclosing TreeGraph has its "showsSubtreeFrames" debug feature enabled, 
        // configure the backing layer to draw its border programmatically.  This is much more efficient
        // than allocating a backing store for each SubtreeView's backing layer, only to stroke a simple
        // rectangle into that backing store.

        PSBaseTreeGraphView *treeGraph = [self enclosingTreeGraph];
        if ([treeGraph showsSubtreeFrames]) {
            [layer setBorderWidth:subtreeBorderWidth()];
            [layer setBorderColor:[subtreeBorderColor() CGColor]];

        } else {
            [layer setBorderWidth:0.0];
        }


    }
}

//3: Potential leak of an object
//6: Calling 'subtreeBorderColor'
//1: Entered call from 'updateSubtreeBorder'
//13: Method returns an Objective-C object with a +0 retain count
//12: Reference count incremented. The object now has a +1 retain count
//6: Returning from 'subtreeBorderColor'
//13: Object leaked: allocated object is not referenced later in this execution path and has a retain count of +1

UPDATE 2: I just completely changed the code and deleted temporary files and cleaned the solution and this is what I see – it is finding errors where there isn’t even code

Answer 1

Simple. You don’t need the call to - retain in the function. That’s exactly what the autorelease pattern is invented for. Since you don’t create the UIColor object using alloc-init, you don’t take ownership of it. No need to superfluously complicate memory management further. 🙂

Edit: (to prevent future downvotes) now that you edited your question and code so that it no longer erroneously returns a retained object, the previous statement is no longer valid. Yes, Xcode shows this notice about the memory leak where “there isn’t even code”, and that’s strange. Yes, perhaps a compiler bug. Still, a temporary (and in my opinion, perfectly valid) workaround is to simply use a define instead of a function. Let’s see what Xcode says if you write this instead:

#define SUBTREE_BORDER_COLOR [UIColor colorWithRed:0.0f green:0.5f blue:0.0f alpha:1.0f]