The a11y test library copies events, there is a case where we send ObjectDestroyed on an object, as opposed to the expected a11y interface. When this happens, the program will crash on a null pointer read. The fix is to support these two scenarios: 1) (object == nullptr, m_uniqueId set) 2) (object != nullptr, m_childId set) For the first case, we no longer have access to the object, so event->object() will be nullptr. This is a change, and happens when the event is sent from the various destructors. For the second case, which happens when the object is still alive, we set m_object, and QAccessibleEvent::accessibleInterface will do the correct thing and return the interface, this is also a change, earlier we would try to access m_uniqueId which was aliased by childId(-1). Fixes: QTBUG-138824 Pick-to: 6.10 Change-Id: If8e4f8d0e26c3c5793f876b1c25b0653621af1e9 Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>