Use public feature flags entry point in exported headers (#58743)

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

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @generated SignedSource<<95f86b3476aeff097f532b10cabf067e>>
+ */
+
+/**
+ * IMPORTANT: Do NOT modify this file directly.
+ *
+ * To change the definition of the flags, edit
+ *   packages/react-native/scripts/featureflags/ReactNativeFeatureFlags.config.js.
+ *
+ * To regenerate this code, run the following script from the repo root:
+ *   yarn featureflags --update
+ */
+
+#include "ReactNativeFeatureFlags.h"
+#include "ReactNativePublicFeatureFlags.h"
+
+namespace facebook::react {
+
+bool ReactNativeFeatureFlags_DO_NOT_USE::enableAccumulatedUpdatesInRawPropsAndroid() {
+  return ReactNativeFeatureFlags::enableAccumulatedUpdatesInRawPropsAndroid();
+}
+
+bool ReactNativeFeatureFlags_DO_NOT_USE::enableCppPropsIteratorSetter() {
+  return ReactNativeFeatureFlags::enableCppPropsIteratorSetter();
+}
+
+bool ReactNativeFeatureFlags_DO_NOT_USE::enableExclusivePropsUpdateAndroid() {
+  return ReactNativeFeatureFlags::enableExclusivePropsUpdateAndroid();
+}
+
+bool ReactNativeFeatureFlags_DO_NOT_USE::enableNativeCSSParsing() {
+  return ReactNativeFeatureFlags::enableNativeCSSParsing();
+}
+
+bool ReactNativeFeatureFlags_DO_NOT_USE::enablePropsUpdateReconciliationAndroid() {
+  return ReactNativeFeatureFlags::enablePropsUpdateReconciliationAndroid();
+}
+
+bool ReactNativeFeatureFlags_DO_NOT_USE::useSharedAnimatedBackend() {
+  return ReactNativeFeatureFlags::useSharedAnimatedBackend();
+}
+
+} // namespace facebook::react

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

@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @generated SignedSource<<39037a69a47b86d0c6643d90f4058002>>
+ */
+
+/**
+ * IMPORTANT: Do NOT modify this file directly.
+ *
+ * To change the definition of the flags, edit
+ *   packages/react-native/scripts/featureflags/ReactNativeFeatureFlags.config.js.
+ *
+ * To regenerate this code, run the following script from the repo root:
+ *   yarn featureflags --update
+ */
+
+#pragma once
+
+#include <string>
+
+#ifndef RN_EXPORT
+#define RN_EXPORT __attribute__((visibility("default")))
+#endif
+
+namespace facebook::react {
+
+/**
+ * This class provides public access to select internal React Native feature flags.
+ */
+class ReactNativeFeatureFlags_DO_NOT_USE {
+ public:
+  /**
+   * When enabled, Android will accumulate updates in rawProps to reduce the number of mounting instructions for cascading re-renders.
+   */
+  RN_EXPORT static bool enableAccumulatedUpdatesInRawPropsAndroid();
+
+  /**
+   * Enable prop iterator setter-style construction of Props in C++ (this flag is not used in Java).
+   */
+  RN_EXPORT static bool enableCppPropsIteratorSetter();
+
+  /**
+   * When enabled, Android will disable Props 1.5 raw value merging when Props 2.0 is available.
+   */
+  RN_EXPORT static bool enableExclusivePropsUpdateAndroid();
+
+  /**
+   * Parse CSS strings using the Fabric CSS parser instead of ViewConfig processing
+   */
+  RN_EXPORT static bool enableNativeCSSParsing();
+
+  /**
+   * When enabled, Android will receive prop updates based on the differences between the last rendered shadow node and the last committed shadow node.
+   */
+  RN_EXPORT static bool enablePropsUpdateReconciliationAndroid();
+
+  /**
+   * Use shared animation backend in C++ Animated
+   */
+  RN_EXPORT static bool useSharedAnimatedBackend();
+};
+
+} // namespace facebook::react

packages/react-native/ReactCommon/react/renderer/attributedstring/conversions.h

@@ -10,7 +10,7 @@
 #include <react/cxxstableapi/FrameworksGuard.h>
 
 #include <react/debug/react_native_expect.h>
-#include <react/featureflags/ReactNativeFeatureFlags.h>
+#include <react/featureflags/ReactNativePublicFeatureFlags.h>
 #include <react/renderer/attributedstring/AttributedString.h>
 #include <react/renderer/attributedstring/ParagraphAttributes.h>
 #include <react/renderer/attributedstring/TextAttributes.h>
@@ -517,7 +517,7 @@ inline void parseUnprocessedFontVariant(const PropsParserContext &context, const
 
 inline void fromRawValue(const PropsParserContext &context, const RawValue &value, FontVariant &result)
 {
-  if (ReactNativeFeatureFlags::enableNativeCSSParsing()) {
+  if (ReactNativeFeatureFlags_DO_NOT_USE::enableNativeCSSParsing()) {
     parseUnprocessedFontVariant(context, value, result);
   } else {
     parseProcessedFontVariant(context, value, result);

packages/react-native/ReactCommon/react/renderer/components/view/BackgroundImagePropsConversions.h

@@ -9,7 +9,7 @@
 
 #include <react/cxxstableapi/UmbrellaGuard.h>
 
-#include <react/featureflags/ReactNativeFeatureFlags.h>
+#include <react/featureflags/ReactNativePublicFeatureFlags.h>
 #include <react/renderer/core/PropsParserContext.h>
 #include <react/renderer/core/RawProps.h>
 #include <react/renderer/graphics/BackgroundImage.h>
@@ -30,7 +30,7 @@ void parseUnprocessedBackgroundImageString(const std::string &value, std::vector
 
 inline void fromRawValue(const PropsParserContext &context, const RawValue &value, std::vector<BackgroundImage> &result)
 {
-  if (ReactNativeFeatureFlags::enableNativeCSSParsing()) {
+  if (ReactNativeFeatureFlags_DO_NOT_USE::enableNativeCSSParsing()) {
     if (value.hasType<std::string>()) {
       parseUnprocessedBackgroundImageString((std::string)value, result);
     } else if (value.hasType<std::vector<RawValue>>()) {

packages/react-native/ReactCommon/react/renderer/components/view/BoxShadowPropsConversions.h

@@ -11,7 +11,7 @@
 
 #include <glog/logging.h>
 #include <react/debug/react_native_expect.h>
-#include <react/featureflags/ReactNativeFeatureFlags.h>
+#include <react/featureflags/ReactNativePublicFeatureFlags.h>
 #include <react/renderer/components/view/CSSConversions.h>
 #include <react/renderer/core/PropsParserContext.h>
 #include <react/renderer/core/RawProps.h>
@@ -255,7 +255,7 @@ parseUnprocessedBoxShadow(const PropsParserContext &context, const RawValue &val
 
 inline void fromRawValue(const PropsParserContext &context, const RawValue &value, std::vector<BoxShadow> &result)
 {
-  if (ReactNativeFeatureFlags::enableNativeCSSParsing()) {
+  if (ReactNativeFeatureFlags_DO_NOT_USE::enableNativeCSSParsing()) {
     parseUnprocessedBoxShadow(context, value, result);
   } else {
     parseProcessedBoxShadow(context, value, result);

packages/react-native/ReactCommon/react/renderer/components/view/FilterPropsConversions.h

@@ -11,7 +11,7 @@
 
 #include <glog/logging.h>
 #include <react/debug/react_native_expect.h>
-#include <react/featureflags/ReactNativeFeatureFlags.h>
+#include <react/featureflags/ReactNativePublicFeatureFlags.h>
 #include <react/renderer/components/view/CSSConversions.h>
 #include <react/renderer/core/PropsParserContext.h>
 #include <react/renderer/core/RawProps.h>
@@ -358,7 +358,7 @@ parseUnprocessedFilter(const PropsParserContext &context, const RawValue &value,
 
 inline void fromRawValue(const PropsParserContext &context, const RawValue &value, std::vector<FilterFunction> &result)
 {
-  if (ReactNativeFeatureFlags::enableNativeCSSParsing()) {
+  if (ReactNativeFeatureFlags_DO_NOT_USE::enableNativeCSSParsing()) {
     parseUnprocessedFilter(context, value, result);
   } else {
     parseProcessedFilter(context, value, result);

packages/react-native/ReactCommon/react/renderer/components/view/conversions.h

@@ -11,7 +11,7 @@
 
 #include <glog/logging.h>
 #include <react/debug/react_native_expect.h>
-#include <react/featureflags/ReactNativeFeatureFlags.h>
+#include <react/featureflags/ReactNativePublicFeatureFlags.h>
 #include <react/renderer/components/view/primitives.h>
 #include <react/renderer/core/LayoutMetrics.h>
 #include <react/renderer/core/PropsParserContext.h>
@@ -520,7 +520,7 @@ inline yoga::FloatOptional convertAspectRatio(const PropsParserContext & /*conte
   if (value.hasType<float>()) {
     return yoga::FloatOptional((float)value);
   }
-  if (ReactNativeFeatureFlags::enableNativeCSSParsing() && value.hasType<std::string>()) {
+  if (ReactNativeFeatureFlags_DO_NOT_USE::enableNativeCSSParsing() && value.hasType<std::string>()) {
     auto ratio = parseCSSProperty<CSSRatio>((std::string)value);
     if (std::holds_alternative<CSSRatio>(ratio)) {
       auto r = std::get<CSSRatio>(ratio);
@@ -995,7 +995,7 @@ inline void parseUnprocessedTransform(const PropsParserContext &context, const R
 
 inline void fromRawValue(const PropsParserContext &context, const RawValue &value, Transform &result)
 {
-  if (ReactNativeFeatureFlags::enableNativeCSSParsing()) {
+  if (ReactNativeFeatureFlags_DO_NOT_USE::enableNativeCSSParsing()) {
     parseUnprocessedTransform(context, value, result);
   } else {
     parseProcessedTransform(context, value, result);
@@ -1079,7 +1079,7 @@ parseUnprocessedTransformOrigin(const PropsParserContext &context, const RawValu
 
 inline void fromRawValue(const PropsParserContext &context, const RawValue &value, TransformOrigin &result)
 {
-  if (ReactNativeFeatureFlags::enableNativeCSSParsing()) {
+  if (ReactNativeFeatureFlags_DO_NOT_USE::enableNativeCSSParsing()) {
     parseUnprocessedTransformOrigin(context, value, result);
   } else {
     parseProcessedTransformOrigin(context, value, result);

packages/react-native/ReactCommon/react/renderer/core/ConcreteComponentDescriptor.h

@@ -13,7 +13,7 @@
 #include <vector>
 
 #include <react/debug/react_native_assert.h>
-#include <react/featureflags/ReactNativeFeatureFlags.h>
+#include <react/featureflags/ReactNativePublicFeatureFlags.h>
 #include <react/renderer/core/ComponentDescriptor.h>
 #include <react/renderer/core/EventDispatcher.h>
 #include <react/renderer/core/Props.h>
@@ -56,7 +56,7 @@ class ConcreteComponentDescriptor : public ComponentDescriptor {
     // iterator-setter path and the runtime flag is on, `parse()` is never
     // called, so the O(n²) preparation here is wasted. Skip it.
     if constexpr (HasIteratorSetterCtor<ConcreteProps>) {
-      if (!ReactNativeFeatureFlags::enableCppPropsIteratorSetter()) {
+      if (!ReactNativeFeatureFlags_DO_NOT_USE::enableCppPropsIteratorSetter()) {
         rawPropsParser_.prepare<ConcreteProps>();
       }
     } else {
@@ -136,7 +136,8 @@ class ConcreteComponentDescriptor : public ComponentDescriptor {
     //    and the only path when the flag is off): parse + per-field
     //    `convertRawProp` via the 3-arg ctor.
     constexpr bool kSupportsIteratorSetter = HasIteratorSetterCtor<ConcreteProps>;
-    const bool useIteratorSetter = kSupportsIteratorSetter && ReactNativeFeatureFlags::enableCppPropsIteratorSetter();
+    const bool useIteratorSetter =
+        kSupportsIteratorSetter && ReactNativeFeatureFlags_DO_NOT_USE::enableCppPropsIteratorSetter();
 
     std::shared_ptr<ConcreteProps> shadowNodeProps;
     if constexpr (kSupportsIteratorSetter) {
@@ -151,11 +152,11 @@ class ConcreteComponentDescriptor : public ComponentDescriptor {
 
 #ifdef RN_SERIALIZABLE_STATE
     bool fallbackToDynamicRawPropsAccumulation = true;
-    if (ReactNativeFeatureFlags::enableExclusivePropsUpdateAndroid() &&
-        ReactNativeFeatureFlags::enableAccumulatedUpdatesInRawPropsAndroid()) {
+    if (ReactNativeFeatureFlags_DO_NOT_USE::enableExclusivePropsUpdateAndroid() &&
+        ReactNativeFeatureFlags_DO_NOT_USE::enableAccumulatedUpdatesInRawPropsAndroid()) {
       // When exclusive props update is enabled, we only apply Props 1.5 processing
       // (raw props merging) when Props 2.0 is not available.
-      if (ReactNativeFeatureFlags::enablePropsUpdateReconciliationAndroid()) {
+      if (ReactNativeFeatureFlags_DO_NOT_USE::enablePropsUpdateReconciliationAndroid()) {
         // Cast to base Props reference to safely call virtual method
         const auto &baseProps = static_cast<const Props &>(*shadowNodeProps);
         if (strcmp(ShadowNodeT::Name(), baseProps.getDiffPropsImplementationTarget()) == 0) {

packages/react-native/ReactCommon/react/renderer/graphics/fromRawValueShared.h

@@ -9,7 +9,7 @@
 
 #include <react/cxxstableapi/UmbrellaGuard.h>
 #include <react/debug/react_native_expect.h>
-#include <react/featureflags/ReactNativeFeatureFlags.h>
+#include <react/featureflags/ReactNativePublicFeatureFlags.h>
 #include <react/renderer/core/RawValue.h>
 #include <react/renderer/css/CSSColor.h>
 #include <react/renderer/css/CSSValueParser.h>
@@ -28,7 +28,7 @@ inline void fromRawValueShared(
 {
   ColorComponents colorComponents = {0, 0, 0, 0};
 
-  if (ReactNativeFeatureFlags::enableNativeCSSParsing() && value.hasType<std::string>()) {
+  if (ReactNativeFeatureFlags_DO_NOT_USE::enableNativeCSSParsing() && value.hasType<std::string>()) {
     auto cssColor = parseCSSProperty<CSSColor>((std::string)value);
     if (std::holds_alternative<CSSColor>(cssColor)) {
       auto c = std::get<CSSColor>(cssColor);

packages/react-native/ReactCommon/react/renderer/mounting/ShadowTree.cpp

@@ -10,6 +10,7 @@
 #include <cxxreact/TraceSection.h>
 #include <jsinspector-modern/tracing/PerformanceTracerSection.h>
 #include <react/debug/react_native_assert.h>
+#include <react/featureflags/ReactNativeFeatureFlags.h>
 #include <react/renderer/components/root/RootComponentDescriptor.h>
 #include <react/renderer/core/LayoutContext.h>
 #include <react/renderer/core/LayoutPrimitives.h>

packages/react-native/ReactCommon/react/renderer/mounting/tests/StackingContextTest.cpp

@@ -9,6 +9,7 @@
 
 #include <gtest/gtest.h>
 
+#include <react/featureflags/ReactNativeFeatureFlags.h>
 #include <react/renderer/componentregistry/ComponentDescriptorProviderRegistry.h>
 #include <react/renderer/components/root/RootComponentDescriptor.h>
 #include <react/renderer/components/scrollview/ScrollViewComponentDescriptor.h>

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

@@ -181,6 +181,7 @@ const definitions: FeatureFlagDefinitions = {
       ossReleaseStage: 'canary',
     },
     enableAccumulatedUpdatesInRawPropsAndroid: {
+      dangerouslyExposeInPublicCppHeaders: true,
       defaultValue: false,
       metadata: {
         dateAdded: '2024-12-10',
@@ -233,6 +234,7 @@ const definitions: FeatureFlagDefinitions = {
       ossReleaseStage: 'none',
     },
     enableCppPropsIteratorSetter: {
+      dangerouslyExposeInPublicCppHeaders: true,
       defaultValue: false,
       metadata: {
         dateAdded: '2024-09-13',
@@ -287,6 +289,7 @@ const definitions: FeatureFlagDefinitions = {
       ossReleaseStage: 'none',
     },
     enableExclusivePropsUpdateAndroid: {
+      dangerouslyExposeInPublicCppHeaders: true,
       defaultValue: false,
       metadata: {
         dateAdded: '2025-11-11',
@@ -517,6 +520,7 @@ const definitions: FeatureFlagDefinitions = {
       ossReleaseStage: 'none',
     },
     enableNativeCSSParsing: {
+      dangerouslyExposeInPublicCppHeaders: true,
       defaultValue: false,
       metadata: {
         dateAdded: '2025-02-07',
@@ -538,6 +542,7 @@ const definitions: FeatureFlagDefinitions = {
       ossReleaseStage: 'none',
     },
     enablePropsUpdateReconciliationAndroid: {
+      dangerouslyExposeInPublicCppHeaders: true,
       defaultValue: false,
       metadata: {
         dateAdded: '2024-07-12',
@@ -923,6 +928,7 @@ const definitions: FeatureFlagDefinitions = {
       ossReleaseStage: 'none',
     },
     useSharedAnimatedBackend: {
+      dangerouslyExposeInPublicCppHeaders: true,
       defaultValue: false,
       metadata: {
         dateAdded: '2025-08-02',

packages/react-native/scripts/featureflags/generateCommonCxxModules.js

@@ -18,6 +18,8 @@ import ReactNativeFeatureFlagsDefaultsH from './templates/common-cxx/ReactNative
 import ReactNativeFeatureFlagsDynamicProviderH from './templates/common-cxx/ReactNativeFeatureFlagsDynamicProvider.h-template';
 import ReactNativeFeatureFlagsOverrides from './templates/common-cxx/ReactNativeFeatureFlagsOverridesOSS_Stage_.h-template';
 import ReactNativeFeatureFlagsProviderH from './templates/common-cxx/ReactNativeFeatureFlagsProvider.h-template';
+import ReactNativePublicFeatureFlagsCPP from './templates/common-cxx/ReactNativePublicFeatureFlags.cpp-template';
+import ReactNativePublicFeatureFlagsH from './templates/common-cxx/ReactNativePublicFeatureFlags.h-template';
 import path from 'node:path';
 
 export default function generateCommonCxxModules(
@@ -30,6 +32,10 @@ export default function generateCommonCxxModules(
       ReactNativeFeatureFlagsH(featureFlagDefinitions),
     [path.join(commonCxxPath, 'ReactNativeFeatureFlags.cpp')]:
       ReactNativeFeatureFlagsCPP(featureFlagDefinitions),
+    [path.join(commonCxxPath, 'ReactNativePublicFeatureFlags.h')]:
+      ReactNativePublicFeatureFlagsH(featureFlagDefinitions),
+    [path.join(commonCxxPath, 'ReactNativePublicFeatureFlags.cpp')]:
+      ReactNativePublicFeatureFlagsCPP(featureFlagDefinitions),
     [path.join(commonCxxPath, 'ReactNativeFeatureFlagsAccessor.h')]:
       ReactNativeFeatureFlagsAccessorH(featureFlagDefinitions),
     [path.join(commonCxxPath, 'ReactNativeFeatureFlagsAccessor.cpp')]:

packages/react-native/scripts/featureflags/generateFiles.js

@@ -34,7 +34,18 @@ export default function generateFiles(
       ...generatorConfig.featureFlagDefinitions,
       common: Object.fromEntries(
         Object.entries(generatorConfig.featureFlagDefinitions.common).filter(
-          ([_, definition]) => !definition.skipNativeAPI,
+          ([name, definition]) => {
+            if (
+              definition.skipNativeAPI &&
+              definition.dangerouslyExposeInPublicCppHeaders
+            ) {
+              throw new Error(
+                `${name} cannot have both skipNativeAPI and dangerouslyExposeInPublicCppHeaders enabled at the same time.`,
+              );
+            }
+
+            return !definition.skipNativeAPI;
+          },
         ),
       ),
     },