IssueTracker

I have created a code sample which shows the issue.

• Android Studio Build: 2022.3.1
• Compose: 1.5.4
• Compose Compiler: 1.5.4
• Kotlin: 1.9.20
• Version of Gradle Plugin: id 'com.android.application' version '8.1.4'
• Version of Gradle: gradle-8.4-bin.zip
• OS: Windows 11 22H2

Steps to Reproduce:

Compile this code and start the TestKeyContent() composable. Observe the log messages.

Result:

The items list contains the elements 1...6 or only 2 (changes every 2 seconds). The element 2 is always part of the items. The composable KeyContent1 should log the message 'KeyContent1 remember 2' only in the composition phase. CORRECT! The composable KeyContent2 should also log the message 'KeyContent2 remember 2' only in the composition phase. BUG! Each recomposition creates a new log message 'KeyContent2 remember 2'.

import androidx.compose.runtime.Composable
import androidx.compose.runtime.key
import androidx.compose.runtime.produceState
import androidx.compose.runtime.remember
import kotlinx.coroutines.delay

@Composable
fun TestKeyContent() {

    val items = produceState(listOf(1, 2, 3, 4, 5, 6)) {

        while (true) {
            delay(2000)
            value = listOf(2)
            delay(2000)
            value = listOf(1, 2, 3, 4, 5, 6)
        }
    }

    KeyContent1(items.value)
    KeyContent2(items.value)
}

@Composable
private fun KeyContent1(items: List<Int>) {

    items.forEach { item ->

        if (item > -1) {

            key(item) {

                remember {
                    println("KeyContent1 remember $item")
                    ""
                }
            }
        }
    }
}

@Composable
private fun KeyContent2(items: List<Int>) {

    for (item in items) {

        if (item > -1) {

            key(item) {

                remember {
                    println("KeyContent2 remember $item")
                    ""
                }
            }
        }
    }
}