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/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 +220,7 @@ internal class ReactInstance(
     // initialized.
     // This happens inside getTurboModuleManagerDelegate getter.
     if (ReactNativeFeatureFlags.useNativeViewConfigsInBridgelessMode()) {
+      UIManagerConstantsCache.maybePreload(context)
       val customDirectEvents: MutableMap<String, Any> = HashMap()
 
       UIConstantsProviderBinding.install(
@@ -232,22 +234,58 @@ internal class ReactInstance(
           // We want to match this beahavior.
           { Arguments.makeNativeMap(UIManagerModuleConstantsHelper.defaultExportableEventTypes) },
           ConstantsForViewManagerProvider { viewManagerName: String ->
+            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)
+            UIManagerConstantsCache.saveConstantsForViewManager(
+                context,
+                viewManagerName,
+                viewManagerConstants,
+                customDirectEvents,
+                context.sourceURL,
+            )
+            Arguments.makeNativeMap(viewManagerConstants)
           },
           {
-            val viewManagers: List<ViewManager<*, *>> =
-                ArrayList(viewManagerResolver.eagerViewManagerMap.values)
-            val constants = createConstants(viewManagers, customDirectEvents)
-
-            val lazyViewManagers = viewManagerResolver.lazyViewManagerNames
-            if (!lazyViewManagers.isEmpty()) {
-              constants["ViewManagerNames"] = ArrayList(lazyViewManagers)
-              constants["LazyViewManagersEnabled"] = true
+            val cachedConstants =
+                UIManagerConstantsCache.getCachedConstants(
+                    context,
+                    customDirectEvents,
+                    context.sourceURL,
+                )
+            if (cachedConstants != null) {
+              cachedConstants
+            } else {
+              val viewManagers: List<ViewManager<*, *>> =
+                  ArrayList(viewManagerResolver.eagerViewManagerMap.values)
+              val constants = createConstants(viewManagers, customDirectEvents)
+
+              val lazyViewManagers = viewManagerResolver.lazyViewManagerNames
+              if (!lazyViewManagers.isEmpty()) {
+                constants["ViewManagerNames"] = ArrayList(lazyViewManagers)
+                constants["LazyViewManagersEnabled"] = true
+              }
+              UIManagerConstantsCache.saveConstants(
+                  context,
+                  constants,
+                  customDirectEvents,
+                  context.sourceURL,
+              )
+              Arguments.makeNativeMap(constants)
             }
-            Arguments.makeNativeMap(constants)
           },
       )
     }
@@ -616,6 +654,14 @@ 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 +670,13 @@ 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()
       }