Objective-c and Xcode strange behavior

Question

In xcode 4.3.1, target iPad 5.1 simulator

• create a single view app

• use ARC, don't use Storyboard

• in ViewController.h

  #import <UIKit/UIKit.h>
  
  @interface ViewController : UIViewController
  {
          NSObject *anObject;
          NSObject *anotherObject;
  }
  
  -(void) makeObjects;
  
  @end
  

• in ViewController.m add

  -(void) makeObjects{
          anObject = [[NSObject alloc] init];
          anotherObject = [[NSObject alloc] init];
  
          int a = 1;
  }
  

• in AppDelegate.m add a line

  - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions: (NSDictionary *)launchOptions
  {
          self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
          // Override point for customization after application launch.
          self.viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
          self.window.rootViewController = self.viewController;
  
          [self.viewController makeObjects]; // ADD THIS LINE  <--------
  
          [self.window makeKeyAndVisible];
          return YES;
  }
  

• in ViewController.m, set a breakpoint at

  anObject = [[NSObject alloc] init];
  

• run

• step over breakpoint
• anObject = 0x00000000, anotherObject is set!

Answer 1

Are you using the LLDB debugger? Currently it doesn't give you correct values on iVars in the simulator. Switch back to GDB and you'll find the correct values reported. I discovered this behavior here: UIViewController subclass can't assign instance variable.

And yes, I reported a bug. I got a response back from Apple stating it is a known issue.