IssueTracker

Jetpack Compose version: Compose Jetpack Compose component used: 1.5.0-alpha02

Probably expected behaviour, but if so not clear it's documented as intended. Also behaviour in tests isn't clear.

The intent of the code is to measure text, then based on it's size, either render that text, or instead render a second text with a different modifier if the text is too long.

Is there a way to dispose an item after measuring instead of placing? I understand this setup allows for items like LazyList.

I can work around this with clearAndSetSemantics, but what caused me to raise this report is testPlacingOnlySecondItemWithSameName failing on the following test, it isn't clear from the dump as it suggests it's positioned at 0,0.

        composeTestRule.onNodeWithText("text").assertIsDisplayed()

Failed to perform isDisplayed check.
Reason: Expected exactly '1' node but found '2' nodes that satisfy: (Text + EditableText contains 'text' (ignoreCase: false))

Dump:

Printing with useUnmergedTree = 'false'
Node #8 at (l=0.0, t=56.0, r=200.0, b=256.0)px
 |-Node #14 at (l=0.0, t=56.0, r=24.0, b=75.0)px
 | Text = '[text]'
 | Actions = [GetTextLayoutResult]
 |-Node #12 at (l=0.0, t=56.0, r=24.0, b=75.0)px
   Text = '[text]'
   Actions = [GetTextLayoutResult]

import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.size
import androidx.compose.runtime.Composable
import androidx.compose.ui.Modifier
import androidx.compose.ui.layout.SubcomposeLayout
import androidx.compose.ui.test.assertIsDisplayed
import androidx.compose.ui.test.assertIsNotDisplayed
import androidx.compose.ui.test.junit4.createComposeRule
import androidx.compose.ui.test.onNodeWithText
import androidx.compose.ui.test.onRoot
import androidx.compose.ui.test.printToString
import androidx.compose.ui.unit.Constraints
import androidx.compose.ui.unit.dp
import androidx.wear.compose.material.Text
import org.junit.Rule
import org.junit.Test
import org.junit.runner.RunWith
import org.robolectric.RobolectricTestRunner
import org.robolectric.annotation.GraphicsMode

@RunWith(RobolectricTestRunner::class)
@GraphicsMode(GraphicsMode.Mode.NATIVE)
class SubcomposeTest {
    @get:Rule
    val composeTestRule = createComposeRule()

    @Test
    fun testPlacingOnlyFirstItem() {
        composeTestRule.setContent {
            TextLayout(useFirst = true, useSuffix = true)
        }

        println(composeTestRule.onRoot().printToString())

        composeTestRule.onNodeWithText("text1").assertIsDisplayed()
        composeTestRule.onNodeWithText("text2").assertDoesNotExist()
    }

    @Test
    fun testPlacingOnlySecondItem() {
        composeTestRule.setContent {
            TextLayout(useFirst = false, useSuffix = true)
        }

        println(composeTestRule.onRoot().printToString())

        composeTestRule.onNodeWithText("text1").assertIsNotDisplayed()
        composeTestRule.onNodeWithText("text2").assertIsDisplayed()
    }

    @Test
    fun testPlacingOnlySecondItemWithSameName() {
        composeTestRule.setContent {
            TextLayout(useFirst = false, useSuffix = false)
        }

        println(composeTestRule.onRoot().printToString())

        composeTestRule.onNodeWithText("text").assertIsDisplayed()
    }

    @Composable
    private fun TextLayout(useFirst: Boolean, useSuffix: Boolean) {
        Box(modifier = Modifier.size(200.dp, 200.dp)) {
            SubcomposeLayout { constraints ->
                val text1 = subcompose(1) {
                    Text(if (useSuffix) "text1" else "text")
                }.first().measure(Constraints())

                if (useFirst) {
                    layout(
                        width = constraints.maxWidth,
                        height = constraints.maxHeight
                    ) {
                        text1.place(0, 0)
                    }
                } else {
                    val text2 = subcompose(2) {
                        Text(if (useSuffix) "text2" else "text")
                    }.first().measure(constraints)

                    layout(
                        width = constraints.maxWidth,
                        height = constraints.maxHeight
                    ) {
                        text2.place(0, 0)
                    }
                }
            }
        }
    }
}