Properly passing NSManagedObjects between views when using ARC? Memory warning & crash

Question

Hi I have a nasty memory management issue under ARC and cannot figure out how to solve it. The problem stands like this, I have these objects:

ObjectManager - a singleton that does fetchRequests to core data and fetches one or more NSManagedObjects

UIViewControllerA - a view controller in which I have a button "PassManagedObject" and a property declared as below:

@property (strong, nonatomic) ManagedObject *objectForToday;

in viewDidLoad on UIViewControllerA , I call the method refreshDailyObject which does this:

self.objectForToday = nil;
self.objectForToday  = [[ObjectManager sharedManager] getDailyObject];

if I tap the PassManagedObject button I create UIViewControllerB , pass the objectForToday to it and display it, see below

- (IBAction)passManagedObjectTapped:(id)sender {
       UIViewControllerB *viewController = [[UIViewControllerB alloc] initWithNibName:@"UIViewControllerB"];
       viewController.object = self.objectForToday;
       [self.navigationController pushViewController:viewController animated:NO];
 }

UIViewControllerB has a property declared like this:

@property (strong, nonatomic) ManagedObject *object;

and a button " Back " which does this:

- (IBAction)backAction:(id)sender {
    self.object = nil;
    [self.navigationController popViewControllerAnimated:NO];
}

Now the problem is this. If I tap continuously passManagedObjectTapped and then backAction, and again passManagedObjectTapped and again backAction and then again passManagedObjectTapped and automate this I'm getting eventually Received Memory Warning 1 , and then crash .

The Instruments doesn't show any leaks but my memory allocation keeps slowly going up.

I am using ARC under iOS4.3 & iOS5. I've been struggling to figuring out what is wrong for a day now. Any help will be highly appreciated.

Thanks!

Answer 1

The self.object = nil; and self.objectForToday = nil; isn't necessary - ARC and the synthesized properties setters already take care of that.

It seems pretty likely that you have a circular reference somewhere. Do you have any situations where object A has a strong reference to object B and object B has a strong reference to object A?

If so, just change one of those references to weak instead (or assign if you want to support iOS 4.3).