Open Radar

 
Summary:
Incorrect behavior is observed on an iPad when a popover is presented, and the user transitions from regular to compact size class. Upon transition between these size classes, UIPresentationController’s delegate is given a chance via  presentationController(_: , viewControllerForAdaptivePresentationStyle) to return a view controller wrapped in a UINavigtationController. When doing this, it is clear the child in the now modally presented view controller (which is now inside a UINavigationController) is given an incorrect size in viewWillTransitionToSize(_:withTransitionCoordinator:). This behavior is not present if not wrapping the view controller in a UINavigationController.

Steps to Reproduce:
1. Create a Universal App.
2. Create a button that can present a view with a presentation style of .Popover
3. Respond to the delegate of the popoverPresentationController’s method presentationController(_:viewControllerForAdaptivePresentationStyle) with the presentationController’s presentedViewController wrapped in a UINavigationController
4. Launch the app on an iPad in landscape.
5. Tap the button to present a popover.
6. Transition into 50/50 Split View


Expected Results:
The size reported to the presented view controller via viewWillTransitionToSize(_:withTransitionCoordinator) should be accurate

Actual Results:
Inaccurate sizes are given.

Version:
iOS 9 13A4325c

Notes:
I've attached a sample project that demonstrates this issue, and the issue of collection view cell sizing that allowed me to stumble onto it. It also contains a screenshot of running the broken and fixed schemes.

It contains two schemes. BrokenTransitionToSizeBroken and BrokenTransitionToSizeFixed. The only difference is that ...Broken defines a flag that responds to presentationController(_:viewControllerForAdaptivePresentationStyle) with the view wrapped in a UINavigationController. The Fixed version simply does not wrap this controller and expected behavior is observed both visibly, and in the console where I'm logging out the expected size.

Configuration:
iPad Air 2 Simulator

Attachments:
'BrokenTransitionToSize.zip' was successfully uploaded.