Memory issue (?) when importing into Swift-based project

[jakintosh]

When importing this code for use in a Swift based SpriteKit (iOS8) project, I would consistently get a crash when trying to run a second animation on top of the queue. After hours of stepping through code, the issue stemmed from assigning _previousAnimation = _currentAnimation in -(void)stopAnimationAndPlayNextInQueue:(BOOL)queueNext which then somehow corrupted the queuedAnimation property.

My solution in the end was to change the property declaration in SGG_Spine.h to read @property (nonatomic, strong) NSString* queuedAnimation. I didn't want to make a pull request because I wasn't 100% sure what the real issue was (or if it would break anything on other target platforms), but I figured I'd leave this here for others to look into, or to save anyone else some time.

The code I was using for those interested:

class GameScene: SKScene {

    var boy: SGG_Spine

    override init(size: CGSize) {
        boy = SGG_Spine.node()
        super.init(size: size)
    }

    required init(coder aDecoder: NSCoder) {
        boy = SGG_Spine.node()
        super.init(coder: aDecoder)
    }

    override func didMoveToView(view: SKView) {
        /* Setup your scene here */
        boy.skeletonFromFileNamed("spineboy", andAtlasNamed: "spineboy", andUseSkinNamed: nil)
        boy.position = CGPointMake(frame.width/2, frame.height/2)
        boy.queuedAnimation = "walk"
        boy.queueIntro = 0.1
        boy.runAnimation("walk", andCount: 0, withIntroPeriodOf: 0.1, andUseQueue: true)
        boy.zPosition = 0
        addChild(boy)
    }

    override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
        /* Called when a touch begins */
        boy.runAnimation("jump", andCount: 0, withIntroPeriodOf: 0.1, andUseQueue: false)
    }

    override func update(currentTime: CFTimeInterval) {
        /* Called before each frame is rendered */
        boy.activateAnimations()
    }
}

When the jump animation completed in touchesBegan() it would crash from trying to access corrupted memory (queuedAnimation).

[mredig]

I haven't played with Swift yet, but my initial thought is that there shouldn't be any issues with implementing this change. The only reason I used "assign" was habit formed as I followed tutorials. I looked up what it was actually doing once, but forgot the details. However, I can't forsee there being any issue with making it strong. I'll look into it a bit when I think of it and have time.