可选的 <String> 到Int64为零，对其进行硬编码

Question

I have a function:

func setId(id: Int64?) {
    self._id = id
}

This function is called here:

let defaults = UserDefaults.standard
let id = defaults.object(forKey: "userId") as? String
if (id != nil) {
    setId(id: Int64(id!))
}

In the function setId() the value of id always seems to be nil. When debugging and stepping one call up in the stack, to the caller (2nd piece of code) the value of id is

po id :

Optional<String>
  - some : "Optional(350350002)"

When I check it as Int64 :

po Int64(id!) : nil

When I check it with a hardcoded value:

po Int64(Optional("350350002")!) :

Optional<Int64>
  - some : 350350002

Also po Int64((id as NSString)) : nil

What is going on here? How does the hardcoded value differ from the actual variable?

Thanks.

Answer 1

The problem was that the following was saved to UserDefaults: String(describing: self._userId) , of course saving the actual word 'Optional(...' with it, as String.

I thought the debugger was showing me an Optional with value 350350002 instead of an actual string: "Optional(350350002)" + the saving to UserDefaults code was not written by me, why I didn't notice this.