なんぞこれ #CodePiece

CodePiece.swift

var player: AVPlayer?

    func testDeallocatePlayerCrashes() {
        player = MyPlayer()
        // NSUnknownKeyException "...was sent to an object that is not KVC-compliant for the "bbbbbbb" property"
        // player?.addObserver(self, forKeyPath: "bbbbbbb.aaaaaaaaa", options: [.new], context: nil)

        // NSInternalInconsistencyException "...was deallocated while key value observers were still registered with it."
        // player?.addObserver(self, forKeyPath: "", options: [.new], context: nil)

        // No crash
        player?.addObserver(self, forKeyPath: "rate", options: [.new], context: nil)
        player = nil // MyPlayer.deinit() is called.
    }