Why does ImmutableList cause recomposition in Jetpack Compose?

Question

In this article, it says that if the argument type of a composable is ImmutableList, it is considered as stable, meaning that if the list didn't change, the composable won't be recomposed.

@Immutable
data class Contact(val name: String, val age: Int)


@Composable
fun ContactRow(contacts: ImmutableList<Contact>, modifier: Modifier = Modifier) {
  var selected by remember { mutableStateOf(false) }
  Row(modifier) {
    ContactDetails(contacts)
    Checkbox(selected, onCheckedChange = {
      selected = !selected
    })
  }
}

@Composable
fun ContactDetails(contacts: ImmutableList<Contact>) {
  Text(text = contacts[0].name)
}

Here, every time I select the checkbox, the ContactDetails composable is recomposed, even though I am using ImmutableList from KotlinX collections.

My compose version is also 1.2.0

Answer 1

There has to be a small mistake on your side. Code presented here is valid, ContactDetails will be skipped, not recomposed. Compiler marks both ContactRow and ContactDetails as stable & skippable.