[swift-users] Why does this leak?

[Rick Aurbach via swift-users]

I have a situation where I have a leak that I do not understand. I would be 
very grateful if someone could explain it to me and offer an idea of how I can 
make the pattern work without leaking:

Consider two code snippets, the first of which leaks, while the second does not.

Case 1: This example leaks 2 32-byte objects..

in FontSelectorDialog.swift:
        override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        switch segue.identifier! {
        < ... >
        
        case "ChooseTextColor" :
                let target = segue.destination as! ColorChooser
                target.textChooserType = .text  // <===
                < ... >
                }
                
        case "ChooseBackgroundColor" :
                let target = segue.destination as! ColorChooser
                target.textChooserType = .bkgnd // <===
                < ... >
                }
                
        default : break
        }

in ColorChooser.swift:

internal enum ColorCat {                        // <===
        case: .text                             // <===
        case: .bkgnd                            // <===
}                                               // <===

internal class ColorChooser : UITableViewController {
        internal var textChooserType : ColorCat = .text // <===
        < ... >
}

Case 2: This example does not leak...

in FontSelectorDialog.swift:
        override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        switch segue.identifier! {
        < ...>
                
        case "ChooseTextColor" :
                let target = segue.destination as! ColorChooser
                target.textChooserType = true   // <===
                < ... >
                }
                
        case "ChooseBackgroundColor" :
                let target = segue.destination as! ColorChooser
                target.textChooserType = false  // <===
                < ... >
                }
                
        default : break
        }

in ColorChooser.swift:

internal class ColorChooser : UITableViewController {
        internal var textChooserType : Bool = true      // <===
        < ... >
}

Can someone explain why? And how can I implement this using an enum. I want to 
use an enum here because:
(a) it is easier to read and understand and seems more “swiftly”
(b) Someday, I may want to add additional options, which would be easy with an 
enum but difficult using the current (Bool) implementation.

Cheers,

Rick Aurbach


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