Cache UIManager constants in bridgeless new architecture on Android (Improve app start on low end/mid android by 150-300ms

packages/gradle-plugin/react-native-gradle-plugin/src/main/kotlin/com/facebook/react/tasks/GenerateEntryPointTask.kt

@@ -72,6 +72,7 @@ abstract class GenerateEntryPointTask : DefaultTask() {
 
         import com.facebook.react.defaults.DefaultNewArchitectureEntryPoint;
         import com.facebook.react.common.annotations.internal.LegacyArchitectureLogger;
+        import com.facebook.react.uimanager.UIManagerConstantsCache;
         import com.facebook.react.views.view.WindowUtilKt;
         import com.facebook.react.soloader.OpenSourceMergedSoMapping;
         import com.facebook.soloader.SoLoader;
@@ -95,6 +96,7 @@ abstract class GenerateEntryPointTask : DefaultTask() {
             
             if ({{packageName}}.BuildConfig.IS_NEW_ARCHITECTURE_ENABLED) {
               DefaultNewArchitectureEntryPoint.load();
+              UIManagerConstantsCache.maybePreload(context);
             }
             
             if ({{packageName}}.BuildConfig.IS_EDGE_TO_EDGE_ENABLED) {

packages/gradle-plugin/react-native-gradle-plugin/src/test/kotlin/com/facebook/react/tasks/GenerateEntryPointTaskTest.kt

@@ -55,6 +55,7 @@ class GenerateEntryPointTaskTest {
 
             import com.facebook.react.defaults.DefaultNewArchitectureEntryPoint;
             import com.facebook.react.common.annotations.internal.LegacyArchitectureLogger;
+            import com.facebook.react.uimanager.UIManagerConstantsCache;
             import com.facebook.react.views.view.WindowUtilKt;
             import com.facebook.react.soloader.OpenSourceMergedSoMapping;
             import com.facebook.soloader.SoLoader;
@@ -78,6 +79,7 @@ class GenerateEntryPointTaskTest {
 
                 if (com.facebook.react.BuildConfig.IS_NEW_ARCHITECTURE_ENABLED) {
                   DefaultNewArchitectureEntryPoint.load();
+                  UIManagerConstantsCache.maybePreload(context);
                 }
 
                 if (com.facebook.react.BuildConfig.IS_EDGE_TO_EDGE_ENABLED) {

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<<5144fb0350b71394206d614c68ef87f0>>
+ * @generated SignedSource<<5765eb9864a1280e5c8706a8cfb22e5b>>
  */
 
 /**
@@ -516,6 +516,12 @@ public object ReactNativeFeatureFlags {
   @JvmStatic
   public fun useNativeViewConfigsInBridgelessMode(): Boolean = accessor.useNativeViewConfigsInBridgelessMode()
 
+  /**
+   * When enabled, bridgeless mode skips the native persisted UIManager constants cache and always computes constants on demand.
+   */
+  @JvmStatic
+  public fun disableNativeUIManagerConstantsCacheInBridgelessMode(): Boolean = accessor.disableNativeUIManagerConstantsCacheInBridgelessMode()
+
   /**
    * When enabled, ReactScrollView will extend NestedScrollView instead of ScrollView on Android for improved nested scrolling support.
    */

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<<d284f066f036908977797a381a044dfa>>
+ * @generated SignedSource<<06438b87ea376f37c31a272e8dc04597>>
  */
 
 /**
@@ -101,6 +101,7 @@ internal class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAcces
   private var useAlwaysAvailableJSErrorHandlingCache: Boolean? = null
   private var useFabricInteropCache: Boolean? = null
   private var useNativeViewConfigsInBridgelessModeCache: Boolean? = null
+  private var disableNativeUIManagerConstantsCacheInBridgelessModeCache: Boolean? = null
   private var useNestedScrollViewAndroidCache: Boolean? = null
   private var useSharedAnimatedBackendCache: Boolean? = null
   private var useTraitHiddenOnAndroidCache: Boolean? = null
@@ -840,6 +841,15 @@ internal class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAcces
     return cached
   }
 
+  override fun disableNativeUIManagerConstantsCacheInBridgelessMode(): Boolean {
+    var cached = disableNativeUIManagerConstantsCacheInBridgelessModeCache
+    if (cached == null) {
+      cached = ReactNativeFeatureFlagsCxxInterop.disableNativeUIManagerConstantsCacheInBridgelessMode()
+      disableNativeUIManagerConstantsCacheInBridgelessModeCache = cached
+    }
+    return cached
+  }
+
   override fun useNestedScrollViewAndroid(): Boolean {
     var cached = useNestedScrollViewAndroidCache
     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<<de1c66a540520cd88c4d358ba30f2c6d>>
+ * @generated SignedSource<<1e88e791ede99c1a251a37405bafdbef>>
  */
 
 /**
@@ -190,6 +190,8 @@ public object ReactNativeFeatureFlagsCxxInterop {
 
   @DoNotStrip @JvmStatic public external fun useNativeViewConfigsInBridgelessMode(): Boolean
 
+  @DoNotStrip @JvmStatic public external fun disableNativeUIManagerConstantsCacheInBridgelessMode(): Boolean
+
   @DoNotStrip @JvmStatic public external fun useNestedScrollViewAndroid(): Boolean
 
   @DoNotStrip @JvmStatic public external fun useSharedAnimatedBackend(): 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<<ab3b1d2277b8cc9db1708ef94515fb35>>
+ * @generated SignedSource<<c84cfe57aee20fe67cd4827cda00876c>>
  */
 
 /**
@@ -185,6 +185,8 @@ public open class ReactNativeFeatureFlagsDefaults : ReactNativeFeatureFlagsProvi
 
   override fun useNativeViewConfigsInBridgelessMode(): Boolean = false
 
+  override fun disableNativeUIManagerConstantsCacheInBridgelessMode(): Boolean = true
+
   override fun useNestedScrollViewAndroid(): Boolean = false
 
   override fun useSharedAnimatedBackend(): 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<<7b87f5541ecf881d8ce51c5edd5b99b0>>
+ * @generated SignedSource<<cfdb8838fe998e0f657de180f3dc271c>>
  */
 
 /**
@@ -105,6 +105,7 @@ internal class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcc
   private var useAlwaysAvailableJSErrorHandlingCache: Boolean? = null
   private var useFabricInteropCache: Boolean? = null
   private var useNativeViewConfigsInBridgelessModeCache: Boolean? = null
+  private var disableNativeUIManagerConstantsCacheInBridgelessModeCache: Boolean? = null
   private var useNestedScrollViewAndroidCache: Boolean? = null
   private var useSharedAnimatedBackendCache: Boolean? = null
   private var useTraitHiddenOnAndroidCache: Boolean? = null
@@ -925,6 +926,16 @@ internal class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcc
     return cached
   }
 
+  override fun disableNativeUIManagerConstantsCacheInBridgelessMode(): Boolean {
+    var cached = disableNativeUIManagerConstantsCacheInBridgelessModeCache
+    if (cached == null) {
+      cached = currentProvider.disableNativeUIManagerConstantsCacheInBridgelessMode()
+      accessedFeatureFlags.add("disableNativeUIManagerConstantsCacheInBridgelessMode")
+      disableNativeUIManagerConstantsCacheInBridgelessModeCache = cached
+    }
+    return cached
+  }
+
   override fun useNestedScrollViewAndroid(): Boolean {
     var cached = useNestedScrollViewAndroidCache
     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<<f34b257861830bae7012fc5201904831>>
+ * @generated SignedSource<<bcd1a8c1320ffe6a5e5b09edcc10652d>>
  */
 
 /**
@@ -185,6 +185,8 @@ public interface ReactNativeFeatureFlagsProvider {
 
   @DoNotStrip public fun useNativeViewConfigsInBridgelessMode(): Boolean
 
+  @DoNotStrip public fun disableNativeUIManagerConstantsCacheInBridgelessMode(): Boolean
+
   @DoNotStrip public fun useNestedScrollViewAndroid(): Boolean
 
   @DoNotStrip public fun useSharedAnimatedBackend(): Boolean

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/runtime/ReactInstance.kt

@@ -65,6 +65,7 @@ import com.facebook.react.uimanager.DisplayMetricsHolder
 import com.facebook.react.uimanager.IllegalViewOperationException
 import com.facebook.react.uimanager.UIConstantsProviderBinding
 import com.facebook.react.uimanager.UIConstantsProviderBinding.ConstantsForViewManagerProvider
+import com.facebook.react.uimanager.UIManagerConstantsCache
 import com.facebook.react.uimanager.UIManagerModuleConstantsHelper
 import com.facebook.react.uimanager.ViewManager
 import com.facebook.react.uimanager.ViewManagerRegistry
@@ -219,6 +220,11 @@ internal class ReactInstance(
     // initialized.
     // This happens inside getTurboModuleManagerDelegate getter.
     if (ReactNativeFeatureFlags.useNativeViewConfigsInBridgelessMode()) {
+      val shouldUseNativeUIManagerConstantsCache =
+          !ReactNativeFeatureFlags.disableNativeUIManagerConstantsCacheInBridgelessMode()
+      if (shouldUseNativeUIManagerConstantsCache) {
+        UIManagerConstantsCache.maybePreload(context)
+      }
       val customDirectEvents: MutableMap<String, Any> = HashMap()
 
       UIConstantsProviderBinding.install(
@@ -232,12 +238,43 @@ internal class ReactInstance(
           // We want to match this beahavior.
           { Arguments.makeNativeMap(UIManagerModuleConstantsHelper.defaultExportableEventTypes) },
           ConstantsForViewManagerProvider { viewManagerName: String ->
+            if (shouldUseNativeUIManagerConstantsCache) {
+              UIManagerConstantsCache
+                  .getCachedConstantsForViewManager(
+                      context,
+                      viewManagerName,
+                      customDirectEvents,
+                      context.sourceURL,
+                  )
+                  ?.let { cachedConstants -> return@ConstantsForViewManagerProvider cachedConstants }
+            }
+
             val viewManager =
                 viewManagerResolver.getViewManager(viewManagerName)
                     ?: return@ConstantsForViewManagerProvider null
-            getConstantsForViewManager(viewManager, customDirectEvents)
+            val viewManagerConstants =
+                createConstantsForViewManagerMap(viewManager, customDirectEvents)
+            if (shouldUseNativeUIManagerConstantsCache) {
+              UIManagerConstantsCache.saveConstantsForViewManager(
+                  context,
+                  viewManagerName,
+                  viewManagerConstants,
+                  customDirectEvents,
+                  context.sourceURL,
+              )
+            }
+            Arguments.makeNativeMap(viewManagerConstants)
           },
           {
+            if (shouldUseNativeUIManagerConstantsCache) {
+              UIManagerConstantsCache
+                  .getCachedConstants(
+                      context,
+                      customDirectEvents,
+                      context.sourceURL,
+                  )
+                  ?.let { cachedConstants -> return@install cachedConstants }
+            }
             val viewManagers: List<ViewManager<*, *>> =
                 ArrayList(viewManagerResolver.eagerViewManagerMap.values)
             val constants = createConstants(viewManagers, customDirectEvents)
@@ -247,6 +284,14 @@ internal class ReactInstance(
               constants["ViewManagerNames"] = ArrayList(lazyViewManagers)
               constants["LazyViewManagersEnabled"] = true
             }
+            if (shouldUseNativeUIManagerConstantsCache) {
+              UIManagerConstantsCache.saveConstants(
+                  context,
+                  constants,
+                  customDirectEvents,
+                  context.sourceURL,
+              )
+            }
             Arguments.makeNativeMap(constants)
           },
       )
@@ -616,6 +661,14 @@ internal class ReactInstance(
         viewManager: ViewManager<*, *>,
         customDirectEvents: MutableMap<String, Any>,
     ): NativeMap {
+      val viewManagerConstants = createConstantsForViewManagerMap(viewManager, customDirectEvents)
+      return Arguments.makeNativeMap(viewManagerConstants)
+    }
+
+    private fun createConstantsForViewManagerMap(
+        viewManager: ViewManager<*, *>,
+        customDirectEvents: MutableMap<String, Any>,
+    ): Map<String, Any?> {
       SystraceMessage.beginSection(
               Systrace.TRACE_TAG_REACT,
               "ReactInstance.getConstantsForViewManager",
@@ -624,15 +677,13 @@ internal class ReactInstance(
           .arg("Lazy", true)
           .flush()
       try {
-        val viewManagerConstants: Map<String, Any> =
-            UIManagerModuleConstantsHelper.createConstantsForViewManager(
+        return UIManagerModuleConstantsHelper.createConstantsForViewManager(
                 viewManager,
                 null,
                 null,
                 null,
                 customDirectEvents,
             )
-        return Arguments.makeNativeMap(viewManagerConstants)
       } finally {
         SystraceMessage.endSection(Systrace.TRACE_TAG_REACT).flush()
       }