```class TestData(val test: String) @Composable fun StableTest() { var state by remember { muta...

# compose

[Marko Novakovic]

class TestData(val test: String)

@Composable
fun StableTest() {
    var state by remember { mutableStateOf(TestData("Marko")) }

    SideEffect {
        println(state.test)
    }

    Text(
        modifier = Modifier
            .clickable { state = TestData("Marko") }
            .padding(32.dp),
        text = state.test,
    )
}

this triggers recomposition, TestData is not stable, but data class TestData(val test: String) doesn’t. Is there a reason to additionally mark data class with @Stable? or is @Stable kind of forcing stability? but adding @Stable to non data class version still triggers recomposition

[Albert Chang]

I don't think this has anything to do with @Stable. @Stable may matters when you directly use the class as the parameter of a composable function. Here you are using a `State`'s value so the difference is because of the results of equals.

[Marko Novakovic]

I see, thanks

[Marko Novakovic]

@Albert Chang how would you modify this example to showcase how @Stable works?

[Albert Chang]

data class TestData(var test: String)

@Composable
fun StableTest() {
    var count by remember { mutableStateOf(0) }
    StableTest(data = TestData("TestData"), count = count) { count++ }
}

@Composable
fun StableTest(data: TestData, count: Int, onClick: () -> Unit) {
    Column {
        StableTest(data)
        Button(onClick = onClick) {
            Text(text = count.toString())
        }
    }
}

@Composable
fun StableTest(data: TestData) {
    println("Function called: ${System.currentTimeMillis()}")
    Text(text = data.test)
}

Add @Stable on TestData and see the difference.

[Marko Novakovic]

I will try it. thanks @Albert Chang