Seems shareFile method not work because UIButton addTarget is weak reference

AddTargetUIButton.swift

import UIKit

class ViewController: UIViewController {

    var testButton: CustomButton {
        let buttonPresenter = ButtonPresenter()
        return buttonPresenter.shareButton
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view.addSubview(testButton)
    }

}

class CustomButton: UIButton {
    //shareFile method will work if I delete 'weak'
    weak var presenter: ButtonPresenter?
    
    init(presenter: ButtonPresenter) {
        self.presenter = presenter
        super.init(frame: CGRect(x: 0, y: 0, width: 200, height: 200))
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

class ButtonPresenter {
    lazy var shareButton: CustomButton = {
        let button = CustomButton(presenter: self)
        button.setTitle("test", for: .normal)
        button.addTarget(self, action: #selector(shareFile(_:)), for: .touchUpInside)
        return button
    }()
    
    @objc private func shareFile(_ button: UIButton) {
        button.setTitle("share file\(arc4random())", for: .normal)
    }
}

DelegateNotWorkIfWeak.swift

import Foundation

protocol ContentDelegate: class {
    func changeText(_ content: Content)
}

class Content {
    var text: String = ""
    //changeText will work if I delete 'weak'
    weak var delegate: ContentDelegate?
}

class Presenter: ContentDelegate {
    lazy var content: Content = {
        let content = Content()
        content.text = "111"
        content.delegate = self
        return content
    }()
    
    func changeText(_ content: Content) {
        content.text = "222"
    }
}

class TestClass {
    lazy var testContent: Content = {
        let presenter = Presenter()
        return presenter.content
    }()
}

let testClass = TestClass()
testClass.testContent.delegate?.changeText(testClass.testContent)
print(testClass.testContent.text)

PassFunctionDirectly

class Content1 {
    var text: String = ""
    var action: ((Content1) -> Void)?
}

class Presenter1 {
    lazy var content: Content1 = {
        let content = Content1()
        content.text = "333"
        content.action = changeText1
        return content
    }()
    
    func changeText1(_ content: Content1) {
        content.text = "444"
    }
}

class TestClass {
    lazy var testContent: Content1 = {
        let presenter = Presenter1()
        return presenter.content
    }()
}

let testClass = TestClass()
if let action = testClass.testContent.action {
    action(testClass.testContent)
}
print(testClass.testContent.text)

• 第一个代码段里，CustomButton如果不存在对ButtonPresenter的strong reference，点击button触发touchUpInside，并不能执行shareFile方法。
• 第二个代码段，weak reference同样会导致Presenter对象被释放，Content的delegate将为nil
• 第三个代码段，不使用Delegate，直接传递function的话，会因为不能添加weak，导致强引用从而隐藏了生命周期的问题
• 推测UIButton的AddTarget与参数的target和action之间为弱引用关系