Xcode UIViewController dealloc breakpoint

dealloc-breakpoint.md

Xcode deinit breakpoint for UIViewController

This breakpoint provides an easy way to track view controller deinitialization (deallocation) in UIKit-based applications. This can help finding memory leaks caused by retain cycles preventing view controllers from being deinitialized when dismissed or popped.

From Cédric Luthi's tweet in 2017:

Useful Xcode breakpoint. When you dismiss a controller and you don’t hear the pop sound (or see the log), you probably have a retain cycle.

Breakpoint Configuration

1. In Xcode, go to the Breakpoint navigator (Cmd+8)
2. At the bottom-left on the screen, tap '+', then select "Symbolic Breakpoint..." from the menu
3. Fill the form:

• Name: UIViewController dealloc
• Symbol: -[UIViewController dealloc]
• Module: UIKitCore (or leave empty)
• Condition: !(BOOL)([[$arg1 description] containsString:@"Input"]) to exclude UIInputViewController, UICompatibilityInputViewController, etc.
• Ignore: leave at zero
• Action: Select "Log Message"
  • Enter: --- dealloc @(id)[$arg1 description]@ @(id)[$arg1 title]@ (or customize as needed)
  • Select "Log message to console"
• Next to "Action: Log Message", tap on '+' to add a new Action
• Select: "Sound" and choose any sound from the list (Submarine, Pop...)
• Check "Automatically continue after evaluating actions" so Xcode does not stop at the breakpoint