From 5c87ca977a144ef6cd48da276383b7250c8998ff Mon Sep 17 00:00:00 2001
From: Peter Abbondanzo <abbo@meta.com>
Date: Fri, 25 Sep 2026 15:46:27 -0700
Subject: [PATCH] Guard RTL overhang handling for fixed-line text (#58685)

Summary:
Pull Request resolved: https://github.com/react/react-native/pull/58685

Add Android regression coverage for exactly constrained RTL text that reserves start-side ink overhang while enforcing a maximum line count and ellipsizing overflow. Also cover the mixed-direction exclusion, where a shared right-side reservation must not be applied.

Changelog: [Internal]

___

Differential Revision: D121670747

fbshipit-source-id: 307461e4ef24d0dad90e609aa8dd7845efc70fa7
---
 .../TextLayoutManagerStartOverhangTest.kt     | 78 +++++++++++++++++--
 1 file changed, 72 insertions(+), 6 deletions(-)

diff --git a/packages/react-native/ReactAndroid/src/test/java/com/facebook/react/views/text/TextLayoutManagerStartOverhangTest.kt b/packages/react-native/ReactAndroid/src/test/java/com/facebook/react/views/text/TextLayoutManagerStartOverhangTest.kt
index cde30f13863..2f23db9c304 100644
--- a/packages/react-native/ReactAndroid/src/test/java/com/facebook/react/views/text/TextLayoutManagerStartOverhangTest.kt
+++ b/packages/react-native/ReactAndroid/src/test/java/com/facebook/react/views/text/TextLayoutManagerStartOverhangTest.kt
@@ -7,6 +7,7 @@
 
 package com.facebook.react.views.text
 
+import android.annotation.SuppressLint
 import android.graphics.RectF
 import android.text.BoringLayout
 import android.text.Layout
@@ -24,6 +25,7 @@ import org.robolectric.RobolectricTestRunner
 import org.robolectric.annotation.Config
 
 @RunWith(RobolectricTestRunner::class)
+@SuppressLint("NewApi")
 class TextLayoutManagerStartOverhangTest {
 
   @Test
@@ -56,6 +58,64 @@ class TextLayoutManagerStartOverhangTest {
     assertThat(TextLayoutManager.getRtlRightOverhang(layout)).isEqualTo(8)
   }
 
+  @Test
+  @Config(sdk = [35])
+  fun `RTL overhang reservation preserves max lines and ellipsis`() {
+    val initialLayout = mock<Layout>()
+    whenever(initialLayout.lineCount).thenReturn(2)
+    whenever(initialLayout.width).thenReturn(LAYOUT_WIDTH.toInt())
+    whenever(initialLayout.getParagraphDirection(any())).thenReturn(Layout.DIR_RIGHT_TO_LEFT)
+    whenever(initialLayout.computeDrawingBoundingBox())
+        .thenReturn(RectF(10f, 0f, LAYOUT_WIDTH + 7.1f, 40f))
+    var rebuiltWidth = 0
+
+    val layout =
+        TextLayoutManager.adjustLayoutForRtlRightOverhang(
+            initialLayout,
+            LAYOUT_WIDTH.toInt(),
+        ) { adjustedWidth ->
+          rebuiltWidth = adjustedWidth
+          createLayout(
+              YogaMeasureMode.EXACTLY,
+              text =
+                  SpannableString(
+                      listOf(
+                              "\u200Ffirst paragraph",
+                              "\u200Fsecond paragraph",
+                              "\u200Fthird paragraph",
+                          )
+                          .joinToString("\n"),
+                  ),
+              layoutWidth = adjustedWidth.toFloat(),
+              ellipsizeMode = TextUtils.TruncateAt.END,
+              maxNumberOfLines = 2,
+          )
+        }
+
+    assertThat(rebuiltWidth).isEqualTo(192)
+    assertThat(layout.width).isEqualTo(rebuiltWidth)
+    assertThat(layout.lineCount).isEqualTo(2)
+    assertThat(layout.getEllipsisCount(layout.lineCount - 1)).isGreaterThan(0)
+  }
+
+  @Test
+  @Config(sdk = [35])
+  fun `mixed direction text does not reserve RTL right overhang`() {
+    val initialLayout = mock<Layout>()
+    whenever(initialLayout.lineCount).thenReturn(2)
+    whenever(initialLayout.width).thenReturn(200)
+    whenever(initialLayout.getParagraphDirection(0)).thenReturn(Layout.DIR_RIGHT_TO_LEFT)
+    whenever(initialLayout.getParagraphDirection(1)).thenReturn(Layout.DIR_LEFT_TO_RIGHT)
+    whenever(initialLayout.computeDrawingBoundingBox()).thenReturn(RectF(10f, 0f, 208f, 40f))
+
+    val layout =
+        TextLayoutManager.adjustLayoutForRtlRightOverhang(initialLayout, 200) {
+          throw AssertionError("Mixed-direction text must not be rebuilt")
+        }
+
+    assertThat(layout).isSameAs(initialLayout)
+  }
+
   @Test
   @Config(sdk = [34])
   fun `EXACTLY mode remains supported before Android 15`() {
@@ -64,9 +124,15 @@ class TextLayoutManagerStartOverhangTest {
     assertThat(layout.width).isEqualTo(LAYOUT_WIDTH.toInt())
   }
 
-  private fun createLayout(widthMode: YogaMeasureMode): Layout {
-    val text = SpannableString("\u0622\u064a\u0629 \u0627\u0644\u0643\u0631\u0633\u064a")
-    val paint = TextPaint(TextPaint.ANTI_ALIAS_FLAG).apply { textSize = 26f }
+  private fun createLayout(
+      widthMode: YogaMeasureMode,
+      text: SpannableString =
+          SpannableString("\u0622\u064a\u0629 \u0627\u0644\u0643\u0631\u0633\u064a"),
+      layoutWidth: Float = LAYOUT_WIDTH,
+      ellipsizeMode: TextUtils.TruncateAt? = null,
+      maxNumberOfLines: Int = 2,
+      paint: TextPaint = TextPaint(TextPaint.ANTI_ALIAS_FLAG).apply { textSize = 26f },
+  ): Layout {
     val method =
         TextLayoutManager::class
             .java
@@ -91,15 +157,15 @@ class TextLayoutManagerStartOverhangTest {
         TextLayoutManager,
         text,
         null,
-        LAYOUT_WIDTH,
+        layoutWidth,
         widthMode,
         /* includeFontPadding = */ false,
         /* textBreakStrategy = */ Layout.BREAK_STRATEGY_HIGH_QUALITY,
         /* hyphenationFrequency = */ Layout.HYPHENATION_FREQUENCY_NONE,
         Layout.Alignment.ALIGN_NORMAL,
         /* justificationMode = */ 0,
-        /* ellipsizeMode = */ null,
-        /* maxNumberOfLines = */ 2,
+        /* ellipsizeMode = */ ellipsizeMode,
+        /* maxNumberOfLines = */ maxNumberOfLines,
         paint,
     ) as Layout
   }