Why do I get a leak when using CFPropertyListCreateDeepCopy?

Question

I am creating a deep mutable copy of a dictionary but for some reason am getting a leak. I've tried this:

NSMutableDictionary *mutableCopy = (NSMutableDictionary *)CFPropertyListCreateDeepCopy(kCFAllocatorDefault, sectionedDictionaryByFirstLetter, kCFPropertyListMutableContainers);
self.copyOfSectionedDictionaryByFirstLetter = mutableCopy;
CFRelease(mutableCopy);

And this:

copyOfSectionedDictionaryByFirstLetter = (NSMutableDictionary *)CFPropertyListCreateDeepCopy(kCFAllocatorDefault, sectionedDictionaryByFirstLetter, kCFPropertyListMutableContainers);

Both are being flagged by interface builder's leaks device.

Any ideas?

Thanks!

Answer 1

Do you actually release copyOfSectionedDictionaryByFirstLetter in your dealloc method?

You will either have to do:

self.copyOfSectionedDictionaryByFirstLetter = nil;

Or:

[copyOfSectionedDictionaryByFirstLetter release];
copyOfSectionedDictionaryByFirstLetter = nil; // Just for good style

Answer 2

My guess is you are retaining one of the objects in the dictionary. What is the number of leaked bytes?

Answer 3

I suspect the immediate case to NSMutableDictionary is confusing the profiler. Try the following:

CFMutableDictionaryRef mutableCopy = CFPropertyListCreateDeepCopy(kCFAllocatorDefault, sectionedDictionaryByFirstLetter, kCFPropertyListMutableContainers);
if (mutableCopy) {
    // NOTE: you MUST check that CFPropertyListCreateDeepCopy() did not return NULL.
    // It can return NULL at any time, and then passing that NULL to CFRelease() will crash your app.
    self.copyOfSectionedDictionaryByFirstLetter = (NSMutableDictionary *)mutableCopy;
    CFRelease(mutableCopy);
}

Answer 4

If you are calling part below multiple times:

NSMutableDictionary *mutableCopy = (NSMutableDictionary *)CFPropertyListCreateDeepCopy(kCFAllocatorDefault, sectionedDictionaryByFirstLetter, kCFPropertyListMutableContainers);
self.copyOfSectionedDictionaryByFirstLetter = mutableCopy;
CFRelease(mutableCopy);

you should change it to:

NSMutableDictionary *mutableCopy = (NSMutableDictionary *)CFPropertyListCreateDeepCopy(kCFAllocatorDefault, sectionedDictionaryByFirstLetter, kCFPropertyListMutableContainers);
[self.copyOfSectionedDictionaryByFirstLetter release];
self.copyOfSectionedDictionaryByFirstLetter = mutableCopy;
CFRelease(mutableCopy);

I guess that can be your reason for the leak.