NSCoder crash on decodeBool forKey (Xcode 8, Swift 3)

Question

I have this simple class

import UIKit

class SimpleModel: NSObject, NSCoding {

    var name : String!
    var done : Bool!

    init(name:String) {
        self.name = name
        self.done = false
    }

    internal required init?(coder aDecoder: NSCoder) {
        self.name = aDecoder.decodeObject(forKey: "name") as! String
        self.done = aDecoder.decodeBool(forKey: "done") // BUG HERE
    }

    func encode(with encoder: NSCoder) {
        encoder.encode(self.name, forKey: "name")
        encoder.encode(self.done, forKey: "done")
    }
}

the save code:

let data = NSKeyedArchiver.archivedData(withRootObject: storageArray)
UserDefaults.standard.set(data, forKey: "storage")
UserDefaults.standard.synchronize()

the read code:

if let data = UserDefaults.standard.data(forKey: "storage") {
    storageArray = NSKeyedUnarchiver.unarchiveObject(with: data) as! [SimpleModel]
}

the problem occurs when the NSKeyedUnarchiver does it's job. I can not understand where the problem comes from.

Thanks!

Answer 1

the trick is remove ! form the primitive types. If you put ! you are saying "make an implicit-unwrapped optional" so the encoder will archive as NSNumber instead of Bool (or Int, Double). If you remove ! the encoder will archive as Bool and things works as expected (I spent an "incident" and this solution is provided by Apple)