ReactiveCocoa 5.0 and UIKit leaks in the iOS 10.0 SDK

[andersio]

What's it about?

Several components are leaking in the iOS SDK. There is no competent workaround viable at the framework level to this.

1. Cocoa extensions from Rex. #3210 (comment)
2. https://github.com/ReactiveX/RxSwift/blob/master/RxCocoa/iOS/UISwitch%2BRx.swift#L22
3. Reporting UIKit iOS 10 issue: Why isn't UISwitch being deallocated ... ever, help wanted. ReactiveX/RxSwift#842

Known Leaking Components

1. UISwitch

Suspected

1. UITextField
2. UITextView

Recommended Workaround

Whenever you use the reactive extensions in Signals or BindingTargets for these components, assume they would never deinitialize.

Limit the lifetime of your bindings using a third source, e.g. the superview, whenever:

1. the bindings must be teared down when the affected view hierarchy is removed; and
2. the source of the bindings would outlive the affected view hierarchy.

Example

This WOULD LEAK if the lifetime of your view model outlives view hierarchy, e.g. you reuse them.

mySwitch.isOn.isEnabled <~ viewModel.isEnabled

Therefore, the binding should be constrained with a lifetime from some others that are not affected by the issue. In the following snippet, it is the ancestor of mySwitch in the view hierarchy.

mySwitch.isOn.isEnabled <~ viewModel.isEnabled.take(during: reactive.lifetime)

Note

This is an iOS specific issue. tvOS is not affected.