How to solve “String interpolation produces a debug description for an optional value; did you mean to make this explicit?” in Xcode 8.3 beta?

Question

Since beta 8.3, zillions warnings \"String interpolation produces a debug description for an optional value; did you mean to make this explicit?\" appeared in my code.

Answer 1

After updating to Xcode 8.3 and getting a lot of warning messages, I came up with the following that is more like the original output behavior, easy to add in, reduces the verboseness of using "String(describing:)" both in code and output.

Basically, add an Optional extension that gives a String describing the thing in the optional, or simply "nil" if not set. In addition, if the thing in the optional is a String, put it in quotes.

extension Optional {
    var orNil : String {
        if self == nil {
            return "nil"
        }
        if "\(Wrapped.self)" == "String" {
            return "\"\(self!)\""
        }
        return "\(self!)"
    }
}

And usage in a playground:

var s : String?
var i : Int?
var d : Double?

var mixed = "s = \(s.orNil)    i = \(i.orNil)   d = \(d.orNil)" // "s = nil    i = nil   d = nil"

d = 3
i = 5
s = ""
mixed = "s = \(s.orNil)    i = \(i.orNil)   d = \(d.orNil)" // "s = ""    i = 5   d = 3.0"

s = "Test"
d = nil
mixed = "s = \(s.orNil)    i = \(i.orNil)   d = \(d.orNil)" // "s = "Test"    i = 5   d = nil"

Thanks for help from following link:

check-if-variable-is-an-optional-and-what-type-it-wraps