In Swift, didSet doesn’t fire when invoked from init()

Question

I’ve got a car and a driver. They mutually reference each other. In the car’s init() I create a driver and assign it to the driver member. The driver member has a didSet method which is supposed to set the driver’s car, thus mutually link them to each other.

class GmDriver {     var car: GmCar! = nil }  class GmCar {     var driver: GmDriver {         didSet {             driver.car = self         }     }     init() {         driver = GmDriver()     } }  let myCar = GmCar() println(myCar.driver.car) // nil 

However, the didSet never fires. Why?

Answer 1

Apple Documentation:

The willSet and didSet observers of superclass properties are called when a property is set in a subclass initializer, after the superclass initializer has been called. They are not called while a class is setting its own properties, before the superclass initializer has been called.

Answer 2

init() {     defer {         driver = GmDriver()     } }