Open Radar

 
Summary:

As of iOS 11.1, [SKAction performSelector:onTarget:] fails to perform a selector on an unretained object in a simple test case.

In iOS 10.3.1, the selector is performed.
Alternately, if either the action or the target are retained elsewhere in the app, the selector is performed.

(Note that `performSelector:onTarget:` is documented to retain its target strongly, and it does, if the action itself is retained.  Perhaps [SKNode runAction] is the culprit?)

Steps to Reproduce:

Starting with the Xcode "Game" template for iOS:

    @implementation GameScene

    - (void)didMoveToView:(SKView *)view {
      LifetimeLogger *lifetimeLogger = [[LifetimeLogger alloc] init];
      SKAction *performSelectorAction = [SKAction performSelector:@selector(aLifetimeLoggerMethod) onTarget:lifetimeLogger];
      [self runAction:performSelectorAction];
    }

    @end

The LifetimeLogger object is an NSObject with simple logging added to init and dealloc:

    @interface LifetimeLogger : NSObject
    - (void)aLifetimeLoggerMethod;
    @end

    @implementation LifetimeLogger

    - (instancetype)init {
      NSLog(@"LifetimeLogger: init");
      return [super init];
    }

    - (void)dealloc {
      NSLog(@"LifetimeLogger: dealloc");
    }

    - (void)aLifetimeLoggerMethod {
      NSLog(@"LifetimeLogger: aLifetimeLoggerMethod");
    }

    @end

Expected Results:

(These results logged using iPhone 6 Simulator iOS 10.3.1.)

  2017-11-30 11:05:57.651 TestPerformSelector[22086:2466019] LifetimeLogger: init
  2017-11-30 11:05:57.654 TestPerformSelector[22086:2466019] LifetimeLogger: aLifetimeLoggerMethod
  2017-11-30 11:05:57.655 TestPerformSelector[22086:2466019] LifetimeLogger: dealloc

Actual Results:

(These results logged using iPhone 6 Simulator iOS 11.1.  The selector is not performed on the target by the action.)

  2017-11-30 10:52:45.247456-0500 TestPerformSelector[21709:2445008] LifetimeLogger: init
  2017-11-30 10:52:45.247737-0500 TestPerformSelector[21709:2445008] LifetimeLogger: dealloc


Version/Build:

n/a

Configuration:

n/a