NullPointerException in BottomSheetNavigator.sheetContent due to retainedEntry race condition

[jackforsky]

Crash:

NullPointerException
    at BottomSheetNavigator$sheetContent$1.invoke$lambda$5$lambda$4(BottomSheetNavigator.kt:166)
    at ComposeBackHandler.onBackCompleted(BackHandler.kt:168)
    at NavigationEventHandler.doOnBackCompleted(NavigationEventHandler.kt:242)
    at NavigationEventProcessor.dispatchOnCompleted(NavigationEventProcessor.kt:487)
    at NavigationEventDispatcher.dispatchOnCompleted(NavigationEventDispatcher.kt:383)
    at DirectNavigationEventInput.backCompleted(DirectNavigationEventInput.kt:55)
    at ComponentActivity.onBackPressed(ComponentActivity.kt:598)
    ...

Description:
BottomSheetNavigator.kt:166 (from androidx.compose.material:material-navigation:1.10.4) crashes with a NullPointerException when a back gesture completes while the bottom sheet is mid-transition. The retainedEntry becomes null between the if (retainedEntry != null) guard (line 163) and the BackHandler callback invocation (line 166).

Crash location

  // BottomSheetNavigator.kt (androidx.compose.material:material-navigation:1.10.4)
  if (retainedEntry != null) {                                          // line 163
      LaunchedEffect(retainedEntry) { sheetState.show() }              // line 164
      BackHandler { state.popWithTransition(popUpTo = retainedEntry!!, saveState = false) } // line 166 — NPE here
  }

The retainedEntry is a produceState value that can become null asynchronously (when backStack emits an empty list during hide animation). The if check passes, Compose registers the BackHandler, but by
the time the predictive back gesture's onBackCompleted fires the callback, retainedEntry has already been set to null.

Suggested fix
Replace the force-unwrap with a null-safe call:

  if (retainedEntry != null) {
      LaunchedEffect(retainedEntry) { sheetState.show() }
      BackHandler {
          retainedEntry?.let { entry ->
              state.popWithTransition(popUpTo = entry, saveState = false)
          }
      }
  }

Environment

• io.github.raamcosta.compose-destinations:bottom-sheet:2.3.0
• androidx.compose.material:material-navigation:1.10.4
• androidx.navigation:navigation-compose:2.9.6