From b90d50432650232fe8bd9fbd44146a5977248362 Mon Sep 17 00:00:00 2001
From: Chris Banes <chrisbanes@users.noreply.github.com>
Date: Tue, 15 Oct 2024 13:34:59 +0100
Subject: [PATCH] Throw error on descendant layouts (#357)

These have never been supported, but it has never been codified...
before this PR.
---
 .../kotlin/dev/chrisbanes/haze/Haze.kt        |  2 ++
 .../dev/chrisbanes/haze/HazeChildNode.kt      |  4 +++
 .../kotlin/dev/chrisbanes/haze/HazeNode.kt    | 31 ++++++++++---------
 .../kotlin/dev/chrisbanes/haze/HazeTest.kt    | 23 ++++++++++++++
 4 files changed, 45 insertions(+), 15 deletions(-)

diff --git a/haze/src/commonMain/kotlin/dev/chrisbanes/haze/Haze.kt b/haze/src/commonMain/kotlin/dev/chrisbanes/haze/Haze.kt
index 2e0328b5..d7b45f71 100644
--- a/haze/src/commonMain/kotlin/dev/chrisbanes/haze/Haze.kt
+++ b/haze/src/commonMain/kotlin/dev/chrisbanes/haze/Haze.kt
@@ -37,6 +37,8 @@ class HazeState {
    */
   var contentLayer: GraphicsLayer? = null
     internal set
+
+  internal var contentDrawing = false
 }
 
 /**
diff --git a/haze/src/commonMain/kotlin/dev/chrisbanes/haze/HazeChildNode.kt b/haze/src/commonMain/kotlin/dev/chrisbanes/haze/HazeChildNode.kt
index 5cd7b022..6217d5c3 100644
--- a/haze/src/commonMain/kotlin/dev/chrisbanes/haze/HazeChildNode.kt
+++ b/haze/src/commonMain/kotlin/dev/chrisbanes/haze/HazeChildNode.kt
@@ -87,6 +87,10 @@ internal class HazeChildNode(
   override fun ContentDrawScope.draw() {
     log(TAG) { "-> HazeChild. start draw()" }
 
+    require(!state.contentDrawing) {
+      "Layout nodes using Modifier.haze and Modifier.hazeChild can not be descendants of each other"
+    }
+
     if (!effect.isValid) {
       // If we don't have any effects, just call drawContent and return early
       drawContent()
diff --git a/haze/src/commonMain/kotlin/dev/chrisbanes/haze/HazeNode.kt b/haze/src/commonMain/kotlin/dev/chrisbanes/haze/HazeNode.kt
index 40097b92..0de7bbb3 100644
--- a/haze/src/commonMain/kotlin/dev/chrisbanes/haze/HazeNode.kt
+++ b/haze/src/commonMain/kotlin/dev/chrisbanes/haze/HazeNode.kt
@@ -38,28 +38,29 @@ internal class HazeNode(
   override val shouldAutoInvalidate: Boolean = false
 
   override fun ContentDrawScope.draw() {
+    state.contentDrawing = true
     log(TAG) { "start draw()" }
 
-    if (!useGraphicLayers()) {
-      // If we're not using graphics layers, just call drawContent and return early
-      drawContent()
-      return
-    }
+    if (useGraphicLayers()) {
+      val graphicsContext = currentValueOf(LocalGraphicsContext)
 
-    val graphicsContext = currentValueOf(LocalGraphicsContext)
+      val contentLayer = state.contentLayer
+        ?.takeUnless { it.isReleased }
+        ?: graphicsContext.createGraphicsLayer().also { state.contentLayer = it }
 
-    val contentLayer = state.contentLayer
-      ?.takeUnless { it.isReleased }
-      ?: graphicsContext.createGraphicsLayer().also { state.contentLayer = it }
+      // First we draw the composable content into a graphics layer
+      contentLayer.record {
+        this@draw.drawContent()
+      }
 
-    // First we draw the composable content into a graphics layer
-    contentLayer.record {
-      this@draw.drawContent()
+      // Now we draw `content` into the window canvas
+      drawLayer(contentLayer)
+    } else {
+      // If we're not using graphics layers, just call drawContent and return early
+      drawContent()
     }
 
-    // Now we draw `content` into the window canvas
-    drawLayer(contentLayer)
-
+    state.contentDrawing = false
     log(TAG) { "end draw()" }
   }
 
diff --git a/haze/src/commonTest/kotlin/dev/chrisbanes/haze/HazeTest.kt b/haze/src/commonTest/kotlin/dev/chrisbanes/haze/HazeTest.kt
index 2aa78785..46c8fd26 100644
--- a/haze/src/commonTest/kotlin/dev/chrisbanes/haze/HazeTest.kt
+++ b/haze/src/commonTest/kotlin/dev/chrisbanes/haze/HazeTest.kt
@@ -3,10 +3,19 @@
 
 package dev.chrisbanes.haze
 
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.test.ExperimentalTestApi
+import androidx.compose.ui.test.runComposeUiTest
+import assertk.assertFailure
 import assertk.assertThat
 import assertk.assertions.isFalse
 import kotlin.test.Test
 
+@OptIn(ExperimentalTestApi::class)
 class HazeTest {
 
   @Test
@@ -20,4 +29,18 @@ class HazeTest {
 
     assertThat(blockCalled).isFalse()
   }
+
+  @Test
+  fun testDescendantModifiers() {
+    assertFailure {
+      runComposeUiTest {
+        setContent {
+          val hazeState = remember { HazeState() }
+          Box(Modifier.haze(hazeState)) {
+            Spacer(Modifier.hazeChild(hazeState, HazeDefaults.style(Color.Blue)))
+          }
+        }
+      }
+    }
+  }
 }