`UISheetPresentationController.prefersGrabberVisible` が `true` だったり、`View.presentationDragIndicator(_:)` が `.visible` だと deinit されない　https://twitter.com/treastrain/status/1669271711269945344

NotCalledDeinitIfPrefersGrabberVisibleIsTrue.swift

//
//  ViewController.swift
//  SheetPresentationControllerPlayground
//
//  Created by Ryoga Tanaka on 2023/06/15.
//

import UIKit

@available(iOS 16.4, *)
final class ViewController: UIViewController {
    @ViewLoading private var button: UIButton
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        var configuration = UIButton.Configuration.plain()
        configuration.title = "Tap me!"
        button = .init(configuration: configuration, primaryAction: .init { [unowned self] _ in
            let viewController = PresentedViewController()
            viewController.sheetPresentationController?.prefersGrabberVisible = true
            present(viewController, animated: true)
        })
        button.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(button)
        NSLayoutConstraint.activate([
            button.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            button.centerYAnchor.constraint(equalTo: view.centerYAnchor),
        ])
    }
}

final class PresentedViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .systemGreen
    }
    
    override func viewDidDisappear(_ animated: Bool) {
        print(self, #function, "is called")
        super.viewDidDisappear(animated)
   }
    
    deinit {
        print(self, "is deinited") // NOT CALLED HERE IF `sheetPresentationController.prefersGrabberVisible` IS `true` !!!
    }
}

NotCalledDeinitIfPresentationDragIndicatorIsVisible.swift

//
//  ContentView.swift
//  PresentationDetentsPlayground
//
//  Created by Ryoga Tanaka on 2023/06/15.
//

import SwiftUI

final class Object: ObservableObject {
  init() {
    print(self, "is inited")
  }
  
  deinit {
    print(self, "is deinited")
  }
}

struct ContentView: View {
  @State private var isPresented = false
  
  var body: some View {
    Button("Tap me!") {
      isPresented = true
    }
    .sheet(isPresented: $isPresented) {
      SheetView()
    }
  }
}

struct SheetView: View {
  @StateObject private var object = Object()
  
  var body: some View {
    Text("Hello, happy world!")
      .presentationDetents([.medium])
      .presentationDragIndicator(.visible) // If this is `.hidden` or this modifier is removed, the `object` will be correctly `deinit`.
  }
}