Make scene provide an AnimatedContentScope to the composable content

[StylianosGakis]

This scope is the one that drives the navigation transition, which allows callers to use it to drive other animations inside the screen itself as it animates into or out of the NavHost.
Notably, this allows callers to use the shared element transitions.

My only one concern left here is that the ComposeRoute interface seems to have been public, even though callers probably had no reason to use the interface in a meaningful way, much less extend it so that this change would be a breaking API change for them. Am I missing something here? Should that change also happen in a backwards compatible way here? Please do let me know if it is the case and I can try and look further into that instead.

Shared more thoughts here #308 (comment)

[StylianosGakis]

I wanted to do something like what androidx.navigation does here https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:navigation/navigation-compose/src/main/java/androidx/navigation/compose/NavGraphBuilder.kt;l=57-60?q=%22ComposeNavigator.Destination(provider%22 which calls this internal deprecated function here https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:navigation/navigation-compose/src/main/java/androidx/navigation/compose/ComposeNavigator.kt;l=106-110 but for them it worked because the API also changed in a meaningful way besides just adding the AnimatedContentScope.

In our case here if I add it as a secondary constructor then there's ambiguity between the two of them and it's impossible to differentiate between the two. So I opted for an internal deprecated function to exist solely for this purpose.

[Tlaster]

The reason ComposeRoute has been made public is simply because I haven’t been diligent enough in tidying up my code. Indeed, it should be internal.
And by the way PreCompsoe uses ktlint with spotless to do the linting things, so make sure to run ./gradlew spotlessApply.

[StylianosGakis]

Thanks for the heads up, I ran ./gradlew spotlessApply and it fixed the 2 places I forgot to add a trailing comma.
And since there's no problem with changing the signature of ComposeRoute then I would say this PR is ready for you to review if you want this change to happen this way or not. I am happy with it as it is 😊

[Tlaster]

Seems like there's a build issue, other than that this PR LGTM!

[StylianosGakis]

The error message was a bit cryptic, but I think my latest commit addresses it.
Let CI run whenever you are able to, and I am hoping it will pass this time

[Tlaster]

Thanks for the PR! LGTM!

[StylianosGakis]

Now we wait for the shared elements APIs to drop in multiplatform, and for SeekableTransition to also update to the new API which those apis rely on.
I wrongly assumed it's CMP lacking behind here JetBrains/compose-multiplatform#4659 but turns out it's just that those are all in the alpha releases. So when CMP starts releasing alphas with 1.7 I will try to come back here and get a sample working again. Hopefully that time without runtime crashes of course 😅