I'm getting a crash for decoration views somewhere inside UIKitCore which is definitely out of my control – the code doesn't dequeue or care about instantiation of decoration views at all – all it does is inserting the registered layout attributes in the flow layout subclass, the rest of it (instantiation of the registered view & queuing/dequeuing) is provided by UIKit.
I have a ton of crashes starting with iOS 18, not a single one on iOS 17 and prior. Call stack:
Thread 1: "*** -[__NSArrayM objectAtIndex:]: index 4 beyond bounds [0 .. 3]"
#1 0x000000018039c67c in -[__NSArrayM objectAtIndex:] ()
#2 0x0000000185a9aa54 in -[_UICollectionViewSubviewManager dequeueReusableViewWithReuseIdentifier:elementKind:elementCategory:] ()
#3 0x00000001851bc3cc in -[UICollectionView _dequeueReusableViewOfKind:withIdentifier:forIndexPath:viewCategory:] ()
#4 0x00000001851a6ab4 in -[UICollectionView _createPreparedSupplementaryViewForElementOfKind:atIndexPath:layout:withLayoutAttributes:applyAttributes:] ()
#5 0x00000001851af69c in -[UICollectionView _createVisibleViewsForSingleCategoryAttributes:limitCreation:fadeForBoundsChange:] ()
#6 0x00000001851af824 in -[UICollectionView _createVisibleViewsForAttributes:fadeForBoundsChange:notifyLayoutForVisibleCellsPass:] ()
#7 0x00000001851ad9c4 in -[UICollectionView _updateVisibleCellsNow:] ()
Array index out of bounds. Definitely not an array in reach, very internal operations. This is also preceded by the following warning thrown into Console:
UICollectionView internal inconsistency: attempted to queue view that is already in the reuse queue. Collection view: <TripItineraryDayCollectionView: 0x146917400; baseClass = UICollectionView; frame = (0 0; 402 682); clipsToBounds = YES; autoresize = W+H; gestureRecognizers = <NSArray: 0x600000e5d770>; backgroundColor = UIExtendedGrayColorSpace 0 0; layer = <CALayer: 0x600000393440>; contentOffset: {0, 0}; contentSize: {402, 662}; adjustedContentInset: {0, 0, 0, 0}; layout: <TripItineraryDayViewLayout: 0x1463d6770>; dataSource: <TripItineraryDayView: 0x1463d6360; frame = (0 102; 402 682); clipsToBounds = YES; autoresize = W+H; backgroundColor = UIExtendedGrayColorSpace 0 0; layer = <CALayer: 0x6000003974a0>>>; view: <TransportLineDecorationView: 0x1059e51a0; baseClass = UICollectionReusableView; frame = (14 257; 54 69); userInteractionEnabled = NO; layer = <CALayer: 0x6000004180c0>>; layout attributes: <TransportDecorationViewLayoutAttributes: 0x1463e34a0; index path: (2-4); element kind: (TripItineraryDayTransportDecorationView); frame = (14 257; 54 69)>
Disabling the decoration views makes the crash go away.
Something has probably changed in iOS 18 which might have sense for cells (where providing the views in the delegate properly is mandatory) or supplementary views, yet it doesn't work really well with decoration views. It gives me the impression that supplementary and decoration views have been merged into one queue stack internally, but something's not right.
