setup an experiment to prevent double measure of text (#44120)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/44120

changelog: [internal]

Prevent measuring the same text twice in `ParagraphShadowNode`.

The current implementation calls `TextLayoutManager::measure` twice for a single `ParagraphShadowNode`. The first time to measure the node for Yoga. The second time inside `ParagraphShadowNode::layout`. I think the original author counted on the cache inside of `TextLayoutManager` to deal with this, but this is not always the case and `TextLayoutManager::measure` is called with two different available widths, leading to cache miss and fills the cache faster.

Reviewed By: NickGerleman

Differential Revision: D55757264

fbshipit-source-id: 0bf8b49f062f802a4e2f04cad1bf1d4bf001b870

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlags.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<7c2d825e15fc7e442034a598eebb6e25>>
+ * @generated SignedSource<<61b929b9624eeaedfa12d2f390299447>>
  */
 
 /**
@@ -106,6 +106,12 @@ public object ReactNativeFeatureFlags {
   @JvmStatic
   public fun inspectorEnableModernCDPRegistry(): Boolean = accessor.inspectorEnableModernCDPRegistry()
 
+  /**
+   * When enabled, ParagraphShadowNode will no longer call measure twice.
+   */
+  @JvmStatic
+  public fun preventDoubleTextMeasure(): Boolean = accessor.preventDoubleTextMeasure()
+
   /**
    * When enabled, it uses the modern fork of RuntimeScheduler that allows scheduling tasks with priorities from any thread.
    */

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsCxxAccessor.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<eb3ae68166b3ec7f797a0db4b2ec1f5b>>
+ * @generated SignedSource<<46e1a8dd088d588ea9eec703d7155710>>
  */
 
 /**
@@ -33,6 +33,7 @@ public class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAccesso
   private var forceBatchingMountItemsOnAndroidCache: Boolean? = null
   private var inspectorEnableCxxInspectorPackagerConnectionCache: Boolean? = null
   private var inspectorEnableModernCDPRegistryCache: Boolean? = null
+  private var preventDoubleTextMeasureCache: Boolean? = null
   private var useModernRuntimeSchedulerCache: Boolean? = null
   private var useNativeViewConfigsInBridgelessModeCache: Boolean? = null
   private var useStateAlignmentMechanismCache: Boolean? = null
@@ -154,6 +155,15 @@ public class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAccesso
     return cached
   }
 
+  override fun preventDoubleTextMeasure(): Boolean {
+    var cached = preventDoubleTextMeasureCache
+    if (cached == null) {
+      cached = ReactNativeFeatureFlagsCxxInterop.preventDoubleTextMeasure()
+      preventDoubleTextMeasureCache = cached
+    }
+    return cached
+  }
+
   override fun useModernRuntimeScheduler(): Boolean {
     var cached = useModernRuntimeSchedulerCache
     if (cached == null) {

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsCxxInterop.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<0b1377acc1a7a2bed8bd6448a54ec91a>>
+ * @generated SignedSource<<56ac4a5eaf65775fdb757fc10ed82908>>
  */
 
 /**
@@ -54,6 +54,8 @@ public object ReactNativeFeatureFlagsCxxInterop {
 
   @DoNotStrip @JvmStatic public external fun inspectorEnableModernCDPRegistry(): Boolean
 
+  @DoNotStrip @JvmStatic public external fun preventDoubleTextMeasure(): Boolean
+
   @DoNotStrip @JvmStatic public external fun useModernRuntimeScheduler(): Boolean
 
   @DoNotStrip @JvmStatic public external fun useNativeViewConfigsInBridgelessMode(): Boolean

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsDefaults.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<545ef5d7c16c2d6599f15a747c53cf3f>>
+ * @generated SignedSource<<6cc4fccd13a1e426a2d6a2a24530e5e6>>
  */
 
 /**
@@ -49,6 +49,8 @@ public open class ReactNativeFeatureFlagsDefaults : ReactNativeFeatureFlagsProvi
 
   override fun inspectorEnableModernCDPRegistry(): Boolean = false
 
+  override fun preventDoubleTextMeasure(): Boolean = false
+
   override fun useModernRuntimeScheduler(): Boolean = false
 
   override fun useNativeViewConfigsInBridgelessMode(): Boolean = false

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsLocalAccessor.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<aa359470a22488b45abfa18b0edadb18>>
+ * @generated SignedSource<<c1c7546acade83cf63f3c06e78352982>>
  */
 
 /**
@@ -37,6 +37,7 @@ public class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcces
   private var forceBatchingMountItemsOnAndroidCache: Boolean? = null
   private var inspectorEnableCxxInspectorPackagerConnectionCache: Boolean? = null
   private var inspectorEnableModernCDPRegistryCache: Boolean? = null
+  private var preventDoubleTextMeasureCache: Boolean? = null
   private var useModernRuntimeSchedulerCache: Boolean? = null
   private var useNativeViewConfigsInBridgelessModeCache: Boolean? = null
   private var useStateAlignmentMechanismCache: Boolean? = null
@@ -171,6 +172,16 @@ public class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcces
     return cached
   }
 
+  override fun preventDoubleTextMeasure(): Boolean {
+    var cached = preventDoubleTextMeasureCache
+    if (cached == null) {
+      cached = currentProvider.preventDoubleTextMeasure()
+      accessedFeatureFlags.add("preventDoubleTextMeasure")
+      preventDoubleTextMeasureCache = cached
+    }
+    return cached
+  }
+
   override fun useModernRuntimeScheduler(): Boolean {
     var cached = useModernRuntimeSchedulerCache
     if (cached == null) {

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsProvider.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<e2eef1313051abddc31e4a3340e72c1c>>
+ * @generated SignedSource<<a5cbe59693a5f7d64af6e004951ab971>>
  */
 
 /**
@@ -49,6 +49,8 @@ public interface ReactNativeFeatureFlagsProvider {
 
   @DoNotStrip public fun inspectorEnableModernCDPRegistry(): Boolean
 
+  @DoNotStrip public fun preventDoubleTextMeasure(): Boolean
+
   @DoNotStrip public fun useModernRuntimeScheduler(): Boolean
 
   @DoNotStrip public fun useNativeViewConfigsInBridgelessMode(): Boolean

packages/react-native/ReactAndroid/src/main/jni/react/featureflags/JReactNativeFeatureFlagsCxxInterop.cpp

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<82163a04d1e3cb54d6c5125173ab807f>>
+ * @generated SignedSource<<f8ac6f7e857808ade5d0f26ec7924604>>
  */
 
 /**
@@ -117,6 +117,12 @@ class ReactNativeFeatureFlagsProviderHolder
     return method(javaProvider_);
   }
 
+  bool preventDoubleTextMeasure() override {
+    static const auto method =
+        getReactNativeFeatureFlagsProviderJavaClass()->getMethod<jboolean()>("preventDoubleTextMeasure");
+    return method(javaProvider_);
+  }
+
   bool useModernRuntimeScheduler() override {
     static const auto method =
         getReactNativeFeatureFlagsProviderJavaClass()->getMethod<jboolean()>("useModernRuntimeScheduler");
@@ -204,6 +210,11 @@ bool JReactNativeFeatureFlagsCxxInterop::inspectorEnableModernCDPRegistry(
   return ReactNativeFeatureFlags::inspectorEnableModernCDPRegistry();
 }
 
+bool JReactNativeFeatureFlagsCxxInterop::preventDoubleTextMeasure(
+    facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop> /*unused*/) {
+  return ReactNativeFeatureFlags::preventDoubleTextMeasure();
+}
+
 bool JReactNativeFeatureFlagsCxxInterop::useModernRuntimeScheduler(
     facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop> /*unused*/) {
   return ReactNativeFeatureFlags::useModernRuntimeScheduler();
@@ -275,6 +286,9 @@ void JReactNativeFeatureFlagsCxxInterop::registerNatives() {
       makeNativeMethod(
         "inspectorEnableModernCDPRegistry",
         JReactNativeFeatureFlagsCxxInterop::inspectorEnableModernCDPRegistry),
+      makeNativeMethod(
+        "preventDoubleTextMeasure",
+        JReactNativeFeatureFlagsCxxInterop::preventDoubleTextMeasure),
       makeNativeMethod(
         "useModernRuntimeScheduler",
         JReactNativeFeatureFlagsCxxInterop::useModernRuntimeScheduler),

packages/react-native/ReactAndroid/src/main/jni/react/featureflags/JReactNativeFeatureFlagsCxxInterop.h

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<48e337d37416ab988ea747050bf207f3>>
+ * @generated SignedSource<<a6b8839cf6f9e87848289a8c5c37a5c8>>
  */
 
 /**
@@ -69,6 +69,9 @@ class JReactNativeFeatureFlagsCxxInterop
   static bool inspectorEnableModernCDPRegistry(
     facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop>);
 
+  static bool preventDoubleTextMeasure(
+    facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop>);
+
   static bool useModernRuntimeScheduler(
     facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop>);
 

packages/react-native/ReactCommon/react/featureflags/ReactNativeFeatureFlags.cpp

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<ddb65722ccc0d584d105b07a621e6871>>
+ * @generated SignedSource<<0fe73e0526dbc2f860029b8cb0fbcfe3>>
  */
 
 /**
@@ -73,6 +73,10 @@ bool ReactNativeFeatureFlags::inspectorEnableModernCDPRegistry() {
   return getAccessor().inspectorEnableModernCDPRegistry();
 }
 
+bool ReactNativeFeatureFlags::preventDoubleTextMeasure() {
+  return getAccessor().preventDoubleTextMeasure();
+}
+
 bool ReactNativeFeatureFlags::useModernRuntimeScheduler() {
   return getAccessor().useModernRuntimeScheduler();
 }

packages/react-native/ReactCommon/react/featureflags/ReactNativeFeatureFlags.h

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<8804fc52ad516ba82c0db6fcdea5f110>>
+ * @generated SignedSource<<d6a33b997461fd186c58a956f6854aca>>
  */
 
 /**
@@ -102,6 +102,11 @@ class ReactNativeFeatureFlags {
    */
   RN_EXPORT static bool inspectorEnableModernCDPRegistry();
 
+  /**
+   * When enabled, ParagraphShadowNode will no longer call measure twice.
+   */
+  RN_EXPORT static bool preventDoubleTextMeasure();
+
   /**
    * When enabled, it uses the modern fork of RuntimeScheduler that allows scheduling tasks with priorities from any thread.
    */

packages/react-native/ReactCommon/react/featureflags/ReactNativeFeatureFlagsAccessor.cpp

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<9f5c5313e139b450449e2716735c26e7>>
+ * @generated SignedSource<<f77452d93caa28c074c6ba8595572e6c>>
  */
 
 /**
@@ -263,6 +263,24 @@ bool ReactNativeFeatureFlagsAccessor::inspectorEnableModernCDPRegistry() {
   return flagValue.value();
 }
 
+bool ReactNativeFeatureFlagsAccessor::preventDoubleTextMeasure() {
+  auto flagValue = preventDoubleTextMeasure_.load();
+
+  if (!flagValue.has_value()) {
+    // This block is not exclusive but it is not necessary.
+    // If multiple threads try to initialize the feature flag, we would only
+    // be accessing the provider multiple times but the end state of this
+    // instance and the returned flag value would be the same.
+
+    markFlagAsAccessed(13, "preventDoubleTextMeasure");
+
+    flagValue = currentProvider_->preventDoubleTextMeasure();
+    preventDoubleTextMeasure_ = flagValue;
+  }
+
+  return flagValue.value();
+}
+
 bool ReactNativeFeatureFlagsAccessor::useModernRuntimeScheduler() {
   auto flagValue = useModernRuntimeScheduler_.load();
 
@@ -272,7 +290,7 @@ bool ReactNativeFeatureFlagsAccessor::useModernRuntimeScheduler() {
     // be accessing the provider multiple times but the end state of this
     // instance and the returned flag value would be the same.
 
-    markFlagAsAccessed(13, "useModernRuntimeScheduler");
+    markFlagAsAccessed(14, "useModernRuntimeScheduler");
 
     flagValue = currentProvider_->useModernRuntimeScheduler();
     useModernRuntimeScheduler_ = flagValue;
@@ -290,7 +308,7 @@ bool ReactNativeFeatureFlagsAccessor::useNativeViewConfigsInBridgelessMode() {
     // be accessing the provider multiple times but the end state of this
     // instance and the returned flag value would be the same.
 
-    markFlagAsAccessed(14, "useNativeViewConfigsInBridgelessMode");
+    markFlagAsAccessed(15, "useNativeViewConfigsInBridgelessMode");
 
     flagValue = currentProvider_->useNativeViewConfigsInBridgelessMode();
     useNativeViewConfigsInBridgelessMode_ = flagValue;
@@ -308,7 +326,7 @@ bool ReactNativeFeatureFlagsAccessor::useStateAlignmentMechanism() {
     // be accessing the provider multiple times but the end state of this
     // instance and the returned flag value would be the same.
 
-    markFlagAsAccessed(15, "useStateAlignmentMechanism");
+    markFlagAsAccessed(16, "useStateAlignmentMechanism");
 
     flagValue = currentProvider_->useStateAlignmentMechanism();
     useStateAlignmentMechanism_ = flagValue;

packages/react-native/ReactCommon/react/featureflags/ReactNativeFeatureFlagsAccessor.h

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<de8d2a8416c3ad914df01b765c8df907>>
+ * @generated SignedSource<<2ac50c51832dfbcebfc8875c02738727>>
  */
 
 /**
@@ -44,6 +44,7 @@ class ReactNativeFeatureFlagsAccessor {
   bool forceBatchingMountItemsOnAndroid();
   bool inspectorEnableCxxInspectorPackagerConnection();
   bool inspectorEnableModernCDPRegistry();
+  bool preventDoubleTextMeasure();
   bool useModernRuntimeScheduler();
   bool useNativeViewConfigsInBridgelessMode();
   bool useStateAlignmentMechanism();
@@ -57,7 +58,7 @@ class ReactNativeFeatureFlagsAccessor {
   std::unique_ptr<ReactNativeFeatureFlagsProvider> currentProvider_;
   bool wasOverridden_;
 
-  std::array<std::atomic<const char*>, 16> accessedFeatureFlags_;
+  std::array<std::atomic<const char*>, 17> accessedFeatureFlags_;
 
   std::atomic<std::optional<bool>> commonTestFlag_;
   std::atomic<std::optional<bool>> batchRenderingUpdatesInEventLoop_;
@@ -72,6 +73,7 @@ class ReactNativeFeatureFlagsAccessor {
   std::atomic<std::optional<bool>> forceBatchingMountItemsOnAndroid_;
   std::atomic<std::optional<bool>> inspectorEnableCxxInspectorPackagerConnection_;
   std::atomic<std::optional<bool>> inspectorEnableModernCDPRegistry_;
+  std::atomic<std::optional<bool>> preventDoubleTextMeasure_;
   std::atomic<std::optional<bool>> useModernRuntimeScheduler_;
   std::atomic<std::optional<bool>> useNativeViewConfigsInBridgelessMode_;
   std::atomic<std::optional<bool>> useStateAlignmentMechanism_;

packages/react-native/ReactCommon/react/featureflags/ReactNativeFeatureFlagsDefaults.h

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<008818e7f2d8b9e295704cccc33758e7>>
+ * @generated SignedSource<<b638a8d33a5b542e93b1bfa784ff500d>>
  */
 
 /**
@@ -79,6 +79,10 @@ class ReactNativeFeatureFlagsDefaults : public ReactNativeFeatureFlagsProvider {
     return false;
   }
 
+  bool preventDoubleTextMeasure() override {
+    return false;
+  }
+
   bool useModernRuntimeScheduler() override {
     return false;
   }

packages/react-native/ReactCommon/react/featureflags/ReactNativeFeatureFlagsProvider.h

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<270291da73cb3e4eddc7bd5cdc9a9470>>
+ * @generated SignedSource<<2ffedc198d97593ae8c5d5300aa640a2>>
  */
 
 /**
@@ -38,6 +38,7 @@ class ReactNativeFeatureFlagsProvider {
   virtual bool forceBatchingMountItemsOnAndroid() = 0;
   virtual bool inspectorEnableCxxInspectorPackagerConnection() = 0;
   virtual bool inspectorEnableModernCDPRegistry() = 0;
+  virtual bool preventDoubleTextMeasure() = 0;
   virtual bool useModernRuntimeScheduler() = 0;
   virtual bool useNativeViewConfigsInBridgelessMode() = 0;
   virtual bool useStateAlignmentMechanism() = 0;

packages/react-native/ReactCommon/react/nativemodule/featureflags/NativeReactNativeFeatureFlags.cpp

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<1abf19f9d1352105511e86c0f217de7a>>
+ * @generated SignedSource<<a24c9972eebff849abd9b0e7ef4ff525>>
  */
 
 /**
@@ -102,6 +102,11 @@ bool NativeReactNativeFeatureFlags::inspectorEnableModernCDPRegistry(
   return ReactNativeFeatureFlags::inspectorEnableModernCDPRegistry();
 }
 
+bool NativeReactNativeFeatureFlags::preventDoubleTextMeasure(
+    jsi::Runtime& /*runtime*/) {
+  return ReactNativeFeatureFlags::preventDoubleTextMeasure();
+}
+
 bool NativeReactNativeFeatureFlags::useModernRuntimeScheduler(
     jsi::Runtime& /*runtime*/) {
   return ReactNativeFeatureFlags::useModernRuntimeScheduler();

packages/react-native/ReactCommon/react/nativemodule/featureflags/NativeReactNativeFeatureFlags.h

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<7a2a41f80549322a7f4255d193dc0b7b>>
+ * @generated SignedSource<<92830e364788db00fd06d4e152ef7727>>
  */
 
 /**
@@ -61,6 +61,8 @@ class NativeReactNativeFeatureFlags
 
   bool inspectorEnableModernCDPRegistry(jsi::Runtime& runtime);
 
+  bool preventDoubleTextMeasure(jsi::Runtime& runtime);
+
   bool useModernRuntimeScheduler(jsi::Runtime& runtime);
 
   bool useNativeViewConfigsInBridgelessMode(jsi::Runtime& runtime);

packages/react-native/ReactCommon/react/renderer/components/text/ParagraphShadowNode.cpp

@@ -10,6 +10,7 @@
 #include <cmath>
 
 #include <react/debug/react_native_assert.h>
+#include <react/featureflags/ReactNativeFeatureFlags.h>
 #include <react/renderer/attributedstring/AttributedStringBox.h>
 #include <react/renderer/components/view/ViewShadowNode.h>
 #include <react/renderer/components/view/conversions.h>
@@ -166,10 +167,10 @@ void ParagraphShadowNode::layout(LayoutContext layoutContext) {
   ensureUnsealed();
 
   auto layoutMetrics = getLayoutMetrics();
-  auto availableSize = layoutMetrics.getContentFrame().size;
+  auto size = layoutMetrics.getContentFrame().size;
 
-  auto layoutConstraints = LayoutConstraints{
-      availableSize, availableSize, layoutMetrics.layoutDirection};
+  auto layoutConstraints =
+      LayoutConstraints{size, size, layoutMetrics.layoutDirection};
   auto content =
       getContentWithMeasuredAttachments(layoutContext, layoutConstraints);
 
@@ -177,15 +178,19 @@ void ParagraphShadowNode::layout(LayoutContext layoutContext) {
 
   TextLayoutContext textLayoutContext{};
   textLayoutContext.pointScaleFactor = layoutContext.pointScaleFactor;
-  auto measurement = textLayoutManager_->measure(
-      AttributedStringBox{content.attributedString},
-      content.paragraphAttributes,
-      textLayoutContext,
-      layoutConstraints);
+  auto measurement = TextMeasurement{};
+
+  if (!ReactNativeFeatureFlags::preventDoubleTextMeasure()) {
+    measurement = textLayoutManager_->measure(
+        AttributedStringBox{content.attributedString},
+        content.paragraphAttributes,
+        textLayoutContext,
+        layoutConstraints);
+  }
 
   if (getConcreteProps().onTextLayout) {
     auto linesMeasurements = textLayoutManager_->measureLines(
-        content.attributedString, content.paragraphAttributes, availableSize);
+        content.attributedString, content.paragraphAttributes, size);
     getConcreteEventEmitter().onTextLayout(linesMeasurements);
   }
 
@@ -194,6 +199,15 @@ void ParagraphShadowNode::layout(LayoutContext layoutContext) {
     return;
   }
 
+  if (ReactNativeFeatureFlags::preventDoubleTextMeasure()) {
+    // Only measure if attachments are not empty.
+    measurement = textLayoutManager_->measure(
+        AttributedStringBox{content.attributedString},
+        content.paragraphAttributes,
+        textLayoutContext,
+        layoutConstraints);
+  }
+
   //  Iterating on attachments, we clone shadow nodes and moving
   //  `paragraphShadowNode` that represents clones of `this` object.
   auto paragraphShadowNode = static_cast<ParagraphShadowNode*>(this);

packages/react-native/ReactCommon/react/renderer/components/text/ParagraphShadowNode.h

@@ -63,6 +63,7 @@ class ParagraphShadowNode final : public ConcreteViewShadowNode<
 #pragma mark - LayoutableShadowNode
 
   void layout(LayoutContext layoutContext) override;
+
   Size measureContent(
       const LayoutContext& layoutContext,
       const LayoutConstraints& layoutConstraints) const override;

packages/react-native/scripts/featureflags/ReactNativeFeatureFlags.config.js

@@ -91,6 +91,11 @@ const definitions: FeatureFlagDefinitions = {
       description:
         'Flag determining if the modern CDP backend should be enabled. This flag is global and should not be changed across React Host lifetimes.',
     },
+    preventDoubleTextMeasure: {
+      defaultValue: false,
+      description:
+        'When enabled, ParagraphShadowNode will no longer call measure twice.',
+    },
     useModernRuntimeScheduler: {
       defaultValue: false,
       description:

packages/react-native/src/private/featureflags/ReactNativeFeatureFlags.js

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<39fd96ed670e0acae857e7fce3377452>>
+ * @generated SignedSource<<0e0858557eb27f3eebfecae18ee13c0b>>
  * @flow strict-local
  */
 
@@ -53,6 +53,7 @@ export type ReactNativeFeatureFlags = {
   forceBatchingMountItemsOnAndroid: Getter<boolean>,
   inspectorEnableCxxInspectorPackagerConnection: Getter<boolean>,
   inspectorEnableModernCDPRegistry: Getter<boolean>,
+  preventDoubleTextMeasure: Getter<boolean>,
   useModernRuntimeScheduler: Getter<boolean>,
   useNativeViewConfigsInBridgelessMode: Getter<boolean>,
   useStateAlignmentMechanism: Getter<boolean>,
@@ -150,6 +151,10 @@ export const inspectorEnableCxxInspectorPackagerConnection: Getter<boolean> = cr
  * Flag determining if the modern CDP backend should be enabled. This flag is global and should not be changed across React Host lifetimes.
  */
 export const inspectorEnableModernCDPRegistry: Getter<boolean> = createNativeFlagGetter('inspectorEnableModernCDPRegistry', false);
+/**
+ * When enabled, ParagraphShadowNode will no longer call measure twice.
+ */
+export const preventDoubleTextMeasure: Getter<boolean> = createNativeFlagGetter('preventDoubleTextMeasure', false);
 /**
  * When enabled, it uses the modern fork of RuntimeScheduler that allows scheduling tasks with priorities from any thread.
  */

packages/react-native/src/private/featureflags/specs/NativeReactNativeFeatureFlags.js

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<99ddb55dadff7adfb02c105984d47cbf>>
+ * @generated SignedSource<<4ba909c3b360c6a4fc9c6ed5996b6a13>>
  * @flow strict-local
  */
 
@@ -36,6 +36,7 @@ export interface Spec extends TurboModule {
   +forceBatchingMountItemsOnAndroid?: () => boolean;
   +inspectorEnableCxxInspectorPackagerConnection?: () => boolean;
   +inspectorEnableModernCDPRegistry?: () => boolean;
+  +preventDoubleTextMeasure?: () => boolean;
   +useModernRuntimeScheduler?: () => boolean;
   +useNativeViewConfigsInBridgelessMode?: () => boolean;
   +useStateAlignmentMechanism?: () => boolean;