[BottomSheetBehavior] Nested scrolling child view does not scroll when its inside nested scrolling parent

Description: When a nested scrolling child view is inside a nested scrolling parent view and the child view changes the scroll position, the touch events get intercepted by the bottom sheet behavior. For example, if I put a ViewPager2 in the bottom sheet dialog and put a vertically scrollable RecyclerView inside the ViewPager2, and navigate to the second page, the RecyclerView becomes unscrollable.

Expected behavior: Nested scrolling child view must be scrollable and should not be intercepted by bottom sheet behavior.

Minimal sample app repro: https://github.com/UdaraWanasinghe/bottom-sheet-nested-scrolling-test

Android API version: All affected.

Material Library version: 1.8.0

Inizia con l’app di esempio minima collegata e riproduci il problema usando un ViewPager2 contenente un RecyclerView scorrevole verticalmente all’interno di un bottom sheet. Poi traccia la gestione dello scorrimento annidato e dell’intercettazione degli eventi touch da parte di BottomSheetBehavior; il lavoro è completo quando RecyclerView rimane scorrevole dopo la navigazione alla seconda pagina nella versione interessata di Material Library.