使用值/状态时的 Android 可组合重构计时

问：

我测试了下面的代码，但是每次我输入 textField 时都会重新组合（每次我输入 textField 时记录显示 2）

@Preview(showBackground = true)
@Composable
fun GreetingPreview() {
    ComposePracticeTheme {
        HomeSection(modifier = Modifier)
    }
}

@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun HomeSection(
    modifier: Modifier = Modifier,
) {
    var input by remember { mutableStateOf("") }
    val isGreen by remember { derivedStateOf(){input.length>5} }
    Log.d("MainActivity", "1");
    Scaffold {paddingValues ->
        Content(modifier = modifier.padding(paddingValues), input = input, isGreen = isGreen, onChange = {input = it})
    }
}

@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun SearchBar(modifier: Modifier, input:String, onChange: (String)->Unit) {
    Surface(modifier = Modifier.padding(8.dp)) {
        TextField(value = input, onValueChange = onChange, modifier = modifier
            .fillMaxWidth()
            .heightIn(min = 56.dp),
            leadingIcon = {
                Icon(painter = painterResource(id = R.drawable.ic_launcher_foreground), contentDescription = "",
                    tint = Color.Unspecified)
            })
    }
}

@Composable
fun Content(modifier: Modifier, input: String, isGreen: Boolean, onChange: (String) -> Unit){
    Log.d("MainActivity", "2");
    Column(horizontalAlignment = Alignment.CenterHorizontally) {
        SearchBar(modifier,input, onChange)
        Text(text = if(isGreen)"is Green" else "is Blue", color = if(isGreen) Color.Green else Color.Blue)
    }
}

但如果我改变

var input by remember { mutableStateOf("") }
val isGreen by remember { derivedStateOf(){input.length>5} }

自

var input = remember { mutableStateOf("") }
val isGreen = remember { derivedStateOf(){input.value.length>5} }

它只有在 isGreen 更改状态时才会重组，为什么使用 value/State 会导致不同的行为？