Open Radar

 
Summary:
-[UIStackView initWithArrangedSubviews:] has an undocumented dependency on its subclass's init(frame: CGRect), which Swift does not require implementing.

Steps to Reproduce:
Write the following code:

class SubclassedStackView: UIStackView {

    init(text: String, subtext: String) {
        let textlabel = UILabel()
        let subtextLabel = UILabel()
        textlabel.text = text
        subtextLabel.text = subtext
        super.init(arrangedSubviews: [textlabel, subtextLabel])
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

If you then use it such as this:

let stackView = SubclassedStackView(text: "Test", subtext: "Uh-oh!")

You get a runtime exception with the following message:

fatal error: use of unimplemented initializer 'init(frame:)' for class 'test.SubclassedStackView'

A look at the call stack shows that the base initializer -[UIStackView initWithArrangedSubviews:] is attempting to call init(frame: CGRect) on the subclass, which is intentionally left unimplemented.

Expected Results:
UIStackView should not call int:frame on its subclass when called by this very subclass's other initialiser.

Actual Results:
fatal error: use of unimplemented initializer 'init(frame:)' for class 'test.SubclassedStackView'

Version:
iOS 9.3.1

Notes:


Configuration:
Any iOS device

Attachments:
'print  10-04-2016, 14-26.crash' was successfully uploaded.