DualNavigationControllersSplitDelegate's `isCollapsedSignal` doesn't work on iOS 13

[nataliq]

Expected Behavior

The isCollapsedSignal on a split view delegate should signal false when both split view controllers are visible.

Current Behavior

The signal doesn't emit any values and its current value is true even when both view controllers are visible. This causes things like MasterDetailSelection to not work properly.

Steps to Reproduce

• Open the Messages example project
• Launch the app on iPad
• Observe the message details aro not automatically shown

More info:

• Place a breakpoint in

• Presentation/Presentation/DualNavigationControllersSplitDelegate.swift

  Line 42 in 940e0d4

  isCollapsedProperty.value = svc.isViewLoaded && svc.view.window != nil ? svc.isCollapsed : true

• The breakpoint never gets hit

Context

• Operating Version: iOS 13 (Xcode 11 GM seed 2)
• Swift version:

Failure Logs