Learn about leaking view controllers without opening Instruments.

First, enable the library by calling (for example from your application delegate):

#if DEBUG
    DeallocationChecker.shared.setup(with: .alert) // There are other options than .alert too!
#endif

Then, in your view controllers from within viewDidDisappear(_:) override, call:

override func viewDidDisappear(_ animated: Bool) {
    super.viewDidDisappear(animated)

    DeallocationChecker.shared.checkDeallocation(of: self)
}

If a view controller isn’t deallocated after disappearing for good, you'll see a helpful alert:

At this point we can simply open the Memory Graph Debugger to investigate the reason of a cycle.

Add the line pod "DeallocationChecker" to your Podfile

Add the line github "fastred/DeallocationChecker" to your Cartfile

Project created by Arek Holko (@arekholko on Twitter).