Has anybody tried `navigation-compose 2.4.0-alpha0...

# compose

[julioromano]

Has anybody tried navigation-compose 2.4.0-alpha05 ? There must have been some behavior changes because my navigation logic now leads to infinite loops which didn’t happen with alpha04.

[Ian Lake]

Quite a bit has changed on alpha05, I'd definitely file a bug with a sample project if you're seeing something unexpected

[julioromano]

Right now I’m seeing infinite loops due to a navigation action I had attached to a SideEffect .
Need to debug more to create something reproducible.

[julioromano]

Yeah, for some reason a SideEffect which used to be triggered only once is now being trigged multiple times, perhaps this is because of the added crossfade navigation animation?

[Ian Lake]

The whole difference between SideEffect and other effects like LaunchedEffect is that side effect runs every composition, so that doesn't seem like the right tool for what you want

[Ian Lake]

Of course, you could wrap your navigate call in if (backStackEntry.lifecycle.currentState == Lifecycle.State.RESUMED) - the Lifecycle gets moved down immediately once you call navigate the first time

[julioromano]

Indeed, though it looks like animations now trigger multiple recompositions (which is expected) so they exposed this flaw of my code.

[julioromano]

I have found another behavior change in alpha05.
ViewModel scoped to a sub navgraph will crash when doing navigateUp() and the viewModel<>() method is called within the composable() lambda.

NavHost(
                        navController = navController,
                        startDestination = "a",
                        modifier = Modifier.fillMaxSize(),
                        route = "mainGraph",
                    ) {
                        composable(route = "a") {
                            ScreenA { navController.navigate("b") }
                        }
                        navigation(
                            startDestination = "b",
                            route = "subGraph",
                        ) {
                            composable(route = "b") {
                                val vm = viewModel<SomeViewModel>(
                                    viewModelStoreOwner = navController.getBackStackEntry("subGraph")
                                )
                                ScreenB { navController.navigateUp() }
                            }
                        }
                    }

Error is: No destination with route subGraph is on the NavController's back stack. The current destination is Destination(0xe5901274) route=a

[julioromano]

Is it me doing something wrong or is this something I should file in a bug report?

[Ian Lake]

Well, it certainly makes sense that when you navigateUp (popping that destination and it's graph) that the graph wouldn't exist anymore, but you should file an issue for that as we should keep that around until the transition completes

[julioromano]

https://issuetracker.google.com/issues/194313238

[julioromano]

FYI: As a workaround I had to move the call to viewModel() inside the screen composable. Since I didn’t want to make the screen composable dependent on NavController I had to use LocalViewModelStoreOwner to indirectly propagate the owner tied to the subgraph:

composable(
                route = "b",
              ) {
                val owner = remember { navController.getBackStackEntry("subGraph") }
                CompositionLocalProvider(
                  LocalViewModelStoreOwner provides owner
                ) {
                  ScreenB { navController.navigateUp() }
                }
              }

[pepos]

It also crashes for me using popUpTo navOption, probably same root cause

[pepos]

https://issuetracker.google.com/issues/194301889

[Ian Lake]

Please file separate issues with projects that reproduce your individual issues, it is much, much easier to dup issues than untangle completely separate issues

[pepos]

done, updated minimum code project to reproduce the issue