memory leaking in custom button memory problems

Question

Trying to figure out why the deinit is not called in OptionsButton class

func getActionButtonView(delegate: DiscoveryActionViewDelegate) -> UIView {
    switch delegate.actionType {
case .showVariants:
    let optionButton = OptionsButton(frame: CGRect(x: 0, y: 0, width: 60, height: 20))
          optionButton.setup()
          optionButton.selectOptionsAction = {
            delegate.showVariants(completionBlock: {  _ in
              optionButton.hideLoader()
            })
          }
          return optionButton
}

The BaseButton is the parent of the HardButton and HardButton is the parent of OptionsButton

class OptionsButton: HardButton {
  var selectOptionsAction: () -> Void = {}

  func setup() {
    setTitleColor(UIColor.color(227, 0, 77), for: .normal)
    backgroundColor = .white
    titleLabel?.font = UIFont.font(weight: .semiBold, style: .footnote1)
    setTitle("list_screen_selectOption_button".localized, for: .normal)
    addTarget(self, action: #selector(buttonAction), for: .touchUpInside)
    borderColor = UIColor.color(227, 0, 77)
    progressColor = UIColor.color(227, 0, 77)
    borderWidth = 1
    cornerRadius = 4
  }

  @objc func buttonAction(sender: HardButton) {
    self.displayLoader()
    self.selectOptionsAction()
  }
    
    deinit {
        print("deinit OptionsBtn")
    }

}

Could anyone help me please the reason or suggest me what's wrong I did? where is/are the leak's

Edit 1-- more code:

enum DiscoveryActionType {
  case cartAction
  case showVariants
  case recommendationCartAction
}

protocol DiscoveryActionViewDelegate: AnyObject {
  func showVariants(completionBlock: @escaping (Bool) -> Void)
  var actionType: DiscoveryActionType { get }
}

Answer 1

You should confirm with “Debug memory graph”, but selectOptionsAction is a closure that has a reference to itself (and delegate, too). This is a classic “strong reference cycle”.

One can use weak references in the capture lists to break the strong reference cycle(s):

let optionButton = OptionsButton(frame: …)
…
optionButton.selectOptionsAction = { [weak delegate] in
    delegate?.showVariants { [weak optionButton] _ in
        optionButton?.hideLoader()
    }
}

You want to make sure that the button does not keep a strong reference to itself. I have also made sure to use a weak reference to delegate, too.

The details may vary, but hopefully this illustrates the idea. Use “debug memory graph” to identify what’s keeping a strong reference to the object in question and use weak references in your capture lists to break the strong reference cycles.

---

See this answer for example of how to use “Debug memory graph” feature.