facebook · mdvacca · Mar 20, 2025 · Mar 20, 2025 · Mar 20, 2025 · Mar 20, 2025
diff --git a/packages/react-native/ReactAndroid/api/ReactAndroid.api b/packages/react-native/ReactAndroid/api/ReactAndroid.api
@@ -4805,6 +4805,8 @@ public abstract interface class com/facebook/react/uimanager/UIManagerModule$Cus
 
 public class com/facebook/react/uimanager/UIManagerModuleConstantsHelper {
 	public fun <init> ()V
+	public static fun createConstants (Ljava/util/List;Ljava/util/Map;Ljava/util/Map;)Ljava/util/Map;
+	public static fun createConstantsForViewManager (Lcom/facebook/react/uimanager/ViewManager;Ljava/util/Map;Ljava/util/Map;Ljava/util/Map;Ljava/util/Map;)Ljava/util/Map;
 	public static fun getDefaultExportableEventTypes ()Ljava/util/Map;
 }
 
@@ -5167,11 +5169,13 @@ public abstract interface annotation class com/facebook/react/uimanager/common/U
 	public static final field Companion Lcom/facebook/react/uimanager/common/UIManagerType$Companion;
 	public static final field DEFAULT I
 	public static final field FABRIC I
+	public static final field LEGACY I
 }
 
 public final class com/facebook/react/uimanager/common/UIManagerType$Companion {
 	public static final field DEFAULT I
 	public static final field FABRIC I
+	public static final field LEGACY I
 }
 
 public final class com/facebook/react/uimanager/common/ViewUtil {

diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/DebugCorePackage.java b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/DebugCorePackage.java
@@ -12,10 +12,10 @@
 import com.facebook.react.bridge.ModuleSpec;
 import com.facebook.react.bridge.NativeModule;
 import com.facebook.react.bridge.ReactApplicationContext;
+import com.facebook.react.bridge.UIManager;
 import com.facebook.react.module.annotations.ReactModuleList;
 import com.facebook.react.module.model.ReactModuleInfo;
 import com.facebook.react.module.model.ReactModuleInfoProvider;
-import com.facebook.react.uimanager.UIManagerModule;
 import com.facebook.react.uimanager.ViewManager;
 import com.facebook.react.views.debuggingoverlay.DebuggingOverlayManager;
 import java.util.ArrayList;
@@ -54,7 +54,7 @@ public Map<String, ReactModuleInfo> getReactModuleInfos() {
   }
 
   /**
-   * @return a map of view managers that should be registered with {@link UIManagerModule}
+   * @return a map of view managers that should be registered with {@link UIManager}
    */
   private Map<String, ModuleSpec> getViewManagersMap() {
     if (mViewManagers == null) {

diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactPackage.kt b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactPackage.kt
@@ -9,9 +9,9 @@ package com.facebook.react
 
 import com.facebook.react.bridge.NativeModule
 import com.facebook.react.bridge.ReactApplicationContext
+import com.facebook.react.bridge.UIManager
 import com.facebook.react.common.annotations.DeprecatedInNewArchitecture
 import com.facebook.react.common.annotations.StableReactNativeAPI
-import com.facebook.react.uimanager.UIManagerModule
 import com.facebook.react.uimanager.ViewManager
 
 /**
@@ -37,7 +37,7 @@ public interface ReactPackage {
   @DeprecatedInNewArchitecture(message = "Migrate to BaseReactPackage and implement getModule")
   public fun createNativeModules(reactContext: ReactApplicationContext): List<NativeModule>
 
-  /** @return a list of view managers that should be registered with [UIManagerModule] */
+  /** @return a list of view managers that should be registered with [UIManager] */
   public fun createViewManagers(
       reactContext: ReactApplicationContext
   ): List<ViewManager<in Nothing, in Nothing>>

diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactRootView.java b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactRootView.java
@@ -9,8 +9,8 @@
 
 import static com.facebook.infer.annotation.ThreadConfined.UI;
 import static com.facebook.react.uimanager.BlendModeHelper.needsIsolatedLayer;
-import static com.facebook.react.uimanager.common.UIManagerType.DEFAULT;
 import static com.facebook.react.uimanager.common.UIManagerType.FABRIC;
+import static com.facebook.react.uimanager.common.UIManagerType.LEGACY;
 import static com.facebook.systrace.Systrace.TRACE_TAG_REACT_JAVA_BRIDGE;
 
 import android.content.Context;
@@ -114,7 +114,7 @@ public interface ReactRootViewEventListener {
   private int mLastHeight = 0;
   private int mLastOffsetX = Integer.MIN_VALUE;
   private int mLastOffsetY = Integer.MIN_VALUE;
-  private @UIManagerType int mUIManagerType = DEFAULT;
+  private @UIManagerType int mUIManagerType = LEGACY;
   private final AtomicInteger mState = new AtomicInteger(STATE_STOPPED);
 
   public ReactRootView(Context context) {
@@ -817,7 +817,7 @@ public void handleException(final Throwable t) {
   }
 
   public void setIsFabric(boolean isFabric) {
-    mUIManagerType = isFabric ? FABRIC : DEFAULT;
+    mUIManagerType = isFabric ? FABRIC : LEGACY;
   }
 
   @Override

diff --git a/...t-native/ReactAndroid/src/main/java/com/facebook/react/animated/NativeAnimatedModule.java b/...t-native/ReactAndroid/src/main/java/com/facebook/react/animated/NativeAnimatedModule.java
@@ -27,6 +27,7 @@
 import com.facebook.react.bridge.WritableArray;
 import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.common.annotations.VisibleForTesting;
+import com.facebook.react.common.build.ReactBuildConfig;
 import com.facebook.react.internal.featureflags.ReactNativeFeatureFlags;
 import com.facebook.react.module.annotations.ReactModule;
 import com.facebook.react.modules.core.ReactChoreographer;
@@ -232,7 +233,7 @@ void executeBatch(long maxBatchNumber, NativeAnimatedNodesManager nodesManager)
   private boolean mInitializedForFabric = false;
   private boolean mInitializedForNonFabric = false;
   private boolean mEnqueuedAnimationOnFrame = false;
-  private @UIManagerType int mUIManagerType = UIManagerType.DEFAULT;
+  private @UIManagerType int mUIManagerType = UIManagerType.LEGACY;
   private int mNumFabricAnimations = 0;
   private int mNumNonFabricAnimations = 0;
 
@@ -387,9 +388,13 @@ public void willDispatchViewUpdates(final UIManager uiManager) {
     if (mOperations.isEmpty() && mPreOperations.isEmpty()) {
       return;
     }
-    if (mUIManagerType == UIManagerType.FABRIC) {
+    if (mUIManagerType == UIManagerType.FABRIC
+        || ReactBuildConfig.UNSTABLE_ENABLE_MINIFY_LEGACY_ARCHITECTURE) {
       return;
     }
+    // The following code ONLY executes for non-fabric
+    // When ReactBuildConfig.UNSTABLE_ENABLE_MINIFY_LEGACY_ARCHITECTURE is true, the folowing code
+    // might be stripped out.
 
     final long frameNo = mCurrentBatchNumber++;
 
@@ -542,8 +547,8 @@ private void decrementInFlightAnimationsForViewTag(final int viewTag) {
       mUIManagerType = UIManagerType.FABRIC;
     } else if (mNumFabricAnimations == 0
         && mNumNonFabricAnimations > 0
-        && mUIManagerType != UIManagerType.DEFAULT) {
-      mUIManagerType = UIManagerType.DEFAULT;
+        && mUIManagerType != UIManagerType.LEGACY) {
+      mUIManagerType = UIManagerType.LEGACY;
     }
   }
 

diff --git a/...act-native/ReactAndroid/src/main/java/com/facebook/react/bridge/NativeModuleRegistry.java b/...act-native/ReactAndroid/src/main/java/com/facebook/react/bridge/NativeModuleRegistry.java
@@ -8,6 +8,8 @@
 package com.facebook.react.bridge;
 
 import com.facebook.infer.annotation.Assertions;
+import com.facebook.react.common.annotations.internal.LegacyArchitectureLogLevel;
+import com.facebook.react.common.annotations.internal.LegacyArchitectureLogger;
 import com.facebook.react.module.annotations.ReactModule;
 import com.facebook.systrace.Systrace;
 import java.util.ArrayList;
@@ -113,6 +115,8 @@ public void onBatchComplete() {
     // short-circuit
     // the search, and simply call OnBatchComplete on the UI Manager.
     // With Fabric, UIManager would no longer be a NativeModule, so this call would simply go away
+    LegacyArchitectureLogger.assertWhenLegacyArchitectureMinifyingEnabled(
+        "NativeModuleRegistry.onBatchComplete()", LegacyArchitectureLogLevel.ERROR);
     ModuleHolder moduleHolder = mModules.get("UIManager");
     if (moduleHolder != null && moduleHolder.hasInstance()) {
       ((OnBatchCompleteListener) moduleHolder.getModule()).onBatchComplete();

diff --git a/...t-native/ReactAndroid/src/main/java/com/facebook/react/modules/core/ReactChoreographer.kt b/...t-native/ReactAndroid/src/main/java/com/facebook/react/modules/core/ReactChoreographer.kt
@@ -26,7 +26,7 @@ public class ReactChoreographer private constructor(choreographerProvider: Chore
   public enum class CallbackType(internal val order: Int) {
     /** For use by perf markers that need to happen immediately after draw */
     PERF_MARKERS(0),
-    /** For use by [com.facebook.react.uimanager.UIManagerModule] */
+    /** For use by [com.facebook.react.bridge.UIManager] */
     DISPATCH_UI(1),
     /** For use by [com.facebook.react.animated.NativeAnimatedModule] */
     NATIVE_ANIMATED_MODULE(2),

diff --git a/...ges/react-native/ReactAndroid/src/main/java/com/facebook/react/runtime/ReactHostImpl.java b/...ges/react-native/ReactAndroid/src/main/java/com/facebook/react/runtime/ReactHostImpl.java
@@ -699,7 +699,9 @@ FabricUIManager getUIManager() {
   /* package */
   @Nullable
   <T extends NativeModule> T getNativeModule(Class<T> nativeModuleInterface) {
-    if (nativeModuleInterface == UIManagerModule.class) {
+    if (!ReactBuildConfig.UNSTABLE_ENABLE_MINIFY_LEGACY_ARCHITECTURE
+        && nativeModuleInterface == UIManagerModule.class) {
+
       ReactSoftExceptionLogger.logSoftExceptionVerbose(
           TAG,
           new ReactNoCrashBridgeNotAllowedSoftException(

diff --git a/...ges/react-native/ReactAndroid/src/main/java/com/facebook/react/runtime/ReactInstance.java b/...ges/react-native/ReactAndroid/src/main/java/com/facebook/react/runtime/ReactInstance.java
@@ -7,6 +7,9 @@
 
 package com.facebook.react.runtime;
 
+import static com.facebook.react.bridge.ReactMarkerConstants.CREATE_UI_MANAGER_MODULE_CONSTANTS_END;
+import static com.facebook.react.bridge.ReactMarkerConstants.CREATE_UI_MANAGER_MODULE_CONSTANTS_START;
+
 import android.content.res.AssetManager;
 import android.view.View;
 import com.facebook.common.logging.FLog;
@@ -29,6 +32,7 @@
 import com.facebook.react.bridge.NativeArray;
 import com.facebook.react.bridge.NativeMap;
 import com.facebook.react.bridge.NativeModule;
+import com.facebook.react.bridge.ReactMarker;
 import com.facebook.react.bridge.ReactNoCrashSoftException;
 import com.facebook.react.bridge.ReactSoftExceptionLogger;
 import com.facebook.react.bridge.RuntimeExecutor;
@@ -60,14 +64,14 @@
 import com.facebook.react.uimanager.DisplayMetricsHolder;
 import com.facebook.react.uimanager.IllegalViewOperationException;
 import com.facebook.react.uimanager.UIConstantsProviderBinding;
-import com.facebook.react.uimanager.UIManagerModule;
 import com.facebook.react.uimanager.UIManagerModuleConstantsHelper;
 import com.facebook.react.uimanager.ViewManager;
 import com.facebook.react.uimanager.ViewManagerRegistry;
 import com.facebook.react.uimanager.ViewManagerResolver;
 import com.facebook.react.uimanager.events.EventDispatcher;
 import com.facebook.soloader.SoLoader;
 import com.facebook.systrace.Systrace;
+import com.facebook.systrace.SystraceMessage;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
@@ -242,15 +246,13 @@ final class ReactInstance {
             if (viewManager == null) {
               return null;
             }
-            return (NativeMap)
-                UIManagerModule.getConstantsForViewManager(viewManager, customDirectEvents);
+            return getConstantsForViewManager(viewManager, customDirectEvents);
           },
           () -> {
             List<ViewManager> viewManagers =
                 new ArrayList<>(mViewManagerResolver.getEagerViewManagerMap().values());
 
-            Map<String, Object> constants =
-                UIManagerModule.createConstants(viewManagers, null, customDirectEvents);
+            Map<String, Object> constants = createConstants(viewManagers, null, customDirectEvents);
 
             Collection<String> lazyViewManagers = mViewManagerResolver.getLazyViewManagerNames();
             if (lazyViewManagers.size() > 0) {
@@ -287,6 +289,40 @@ final class ReactInstance {
     Systrace.endSection(Systrace.TRACE_TAG_REACT_JAVA_BRIDGE);
   }
 
+  private static Map<String, Object> createConstants(
+      List<ViewManager> viewManagers,
+      @Nullable Map<String, Object> customBubblingEvents,
+      @Nullable Map<String, Object> customDirectEvents) {
+    ReactMarker.logMarker(CREATE_UI_MANAGER_MODULE_CONSTANTS_START);
+    SystraceMessage.beginSection(Systrace.TRACE_TAG_REACT_JAVA_BRIDGE, "CreateUIManagerConstants")
+        .arg("Lazy", false)
+        .flush();
+    try {
+      return UIManagerModuleConstantsHelper.createConstants(
+          viewManagers, customBubblingEvents, customDirectEvents);
+    } finally {
+      Systrace.endSection(Systrace.TRACE_TAG_REACT_JAVA_BRIDGE);
+      ReactMarker.logMarker(CREATE_UI_MANAGER_MODULE_CONSTANTS_END);
+    }
+  }
+
+  private static NativeMap getConstantsForViewManager(
+      ViewManager viewManager, Map<String, Object> customDirectEvents) {
+    SystraceMessage.beginSection(
+            Systrace.TRACE_TAG_REACT_JAVA_BRIDGE, "ReactInstance.getConstantsForViewManager")
+        .arg("ViewManager", viewManager.getName())
+        .arg("Lazy", true)
+        .flush();
+    try {
+      Map<String, Object> viewManagerConstants =
+          UIManagerModuleConstantsHelper.createConstantsForViewManager(
+              viewManager, null, null, null, customDirectEvents);
+      return Arguments.makeNativeMap(viewManagerConstants);
+    } finally {
+      SystraceMessage.endSection(Systrace.TRACE_TAG_REACT_JAVA_BRIDGE).flush();
+    }
+  }
+
   void initializeEagerTurboModules() {
     mQueueConfiguration
         .getNativeModulesQueueThread()

diff --git a/...es/react-native/ReactAndroid/src/main/java/com/facebook/react/touch/JSResponderHandler.kt b/...es/react-native/ReactAndroid/src/main/java/com/facebook/react/touch/JSResponderHandler.kt
@@ -12,7 +12,7 @@ import android.view.ViewGroup
 import android.view.ViewParent
 
 /**
- * This class coordinates JSResponder commands for [UIManagerModule]. It should be set as
+ * This class coordinates JSResponder commands for [UIManager]. It should be set as
  * OnInterceptTouchEventListener for all newly created native views that implements [ ] and thanks
  * to the information whether JSResponder is set and to which view it will correctly coordinate the
  * return values of [OnInterceptTouchEventListener] such that touch events will be dispatched to the

diff --git a/...react-native/ReactAndroid/src/main/java/com/facebook/react/uimanager/UIManagerHelper.java b/...react-native/ReactAndroid/src/main/java/com/facebook/react/uimanager/UIManagerHelper.java
@@ -22,6 +22,8 @@
 import com.facebook.react.bridge.ReactNoCrashSoftException;
 import com.facebook.react.bridge.ReactSoftExceptionLogger;
 import com.facebook.react.bridge.UIManager;
+import com.facebook.react.common.annotations.internal.LegacyArchitectureLogLevel;
+import com.facebook.react.common.annotations.internal.LegacyArchitectureLogger;
 import com.facebook.react.uimanager.common.UIManagerType;
 import com.facebook.react.uimanager.events.EventDispatcher;
 import com.facebook.react.uimanager.events.EventDispatcherProvider;
@@ -69,6 +71,14 @@ private static UIManager getUIManager(
       return uiManager;
     }
 
+    // The following code is compiled-out when `context.isBridgeless() == true &&
+    // ReactBuildConfig.UNSTABLE_ENABLE_MINIFY_LEGACY_ARCHITECTURE == true ` because:
+    // - BridgelessReactContext.isBridgeless() is set to true statically
+    // - BridgeReactContext is compiled-out when UNSTABLE_ENABLE_MINIFY_LEGACY_ARCHITECTURE == true
+    //
+    // To detect a potential regression we add the following assertion ERROR
+    LegacyArchitectureLogger.assertWhenLegacyArchitectureMinifyingEnabled(
+        "UIManagerHelper.getUIManager(context, uiManagerType)", LegacyArchitectureLogLevel.ERROR);
     if (!context.hasCatalystInstance()) {
       ReactSoftExceptionLogger.logSoftException(
           TAG,
@@ -181,7 +191,7 @@ public static int getSurfaceId(View view) {
     int reactTag = view.getId();
 
     // In non-Fabric we don't have (or use) SurfaceId
-    if (getUIManagerType(reactTag) == UIManagerType.DEFAULT) {
+    if (getUIManagerType(reactTag) == UIManagerType.LEGACY) {
       return -1;
     }
 

diff --git a/...react-native/ReactAndroid/src/main/java/com/facebook/react/uimanager/UIManagerModule.java b/...react-native/ReactAndroid/src/main/java/com/facebook/react/uimanager/UIManagerModule.java
@@ -9,8 +9,8 @@
 
 import static com.facebook.react.bridge.ReactMarkerConstants.CREATE_UI_MANAGER_MODULE_CONSTANTS_END;
 import static com.facebook.react.bridge.ReactMarkerConstants.CREATE_UI_MANAGER_MODULE_CONSTANTS_START;
-import static com.facebook.react.uimanager.common.UIManagerType.DEFAULT;
 import static com.facebook.react.uimanager.common.UIManagerType.FABRIC;
+import static com.facebook.react.uimanager.common.UIManagerType.LEGACY;
 
 import android.content.ComponentCallbacks2;
 import android.content.res.Configuration;
@@ -185,7 +185,7 @@ public void initialize() {
     getReactApplicationContext().registerComponentCallbacks(mMemoryTrimCallback);
     getReactApplicationContext().registerComponentCallbacks(mViewManagerRegistry);
     mEventDispatcher.registerEventEmitter(
-        DEFAULT, getReactApplicationContext().getJSModule(RCTEventEmitter.class));
+        LEGACY, getReactApplicationContext().getJSModule(RCTEventEmitter.class));
   }
 
   @Override
@@ -851,7 +851,7 @@ public void receiveEvent(int reactTag, String eventName, @Nullable WritableMap e
   @Override
   public void receiveEvent(
       int surfaceId, int reactTag, String eventName, @Nullable WritableMap event) {
-    assert ViewUtil.getUIManagerType(reactTag) == DEFAULT;
+    assert ViewUtil.getUIManagerType(reactTag) == LEGACY;
     getReactApplicationContext()
         .getJSModule(RCTEventEmitter.class)
         .receiveEvent(reactTag, eventName, event);

diff --git a/...actAndroid/src/main/java/com/facebook/react/uimanager/UIManagerModuleConstantsHelper.java b/...actAndroid/src/main/java/com/facebook/react/uimanager/UIManagerModuleConstantsHelper.java
@@ -86,7 +86,9 @@ private static void validateDirectEventNames(
    * into the map of {@link UIManagerModule} base constants that is stored in {@link
    * UIManagerModuleConstants}. TODO(6845124): Create a test for this
    */
-  /* package */ static Map<String, Object> createConstants(
+  // NOTE: When converted to Kotlin this method should be `internal` due to
+  // visibility restriction for `ReactInstance`
+  public static Map<String, Object> createConstants(
       List<ViewManager> viewManagers,
       @Nullable Map<String, Object> allBubblingEventTypes,
       @Nullable Map<String, Object> allDirectEventTypes) {
@@ -124,7 +126,9 @@ private static void validateDirectEventNames(
     return constants;
   }
 
-  /* package */ static Map<String, Object> createConstantsForViewManager(
+  // NOTE: When converted to Kotlin this method should be `internal` due to
+  // visibility restriction for `ReactInstance`
+  public static Map<String, Object> createConstantsForViewManager(
       ViewManager viewManager,
       @Nullable Map defaultBubblingEvents,
       @Nullable Map defaultDirectEvents,

diff --git a/...ct-native/ReactAndroid/src/main/java/com/facebook/react/uimanager/common/UIManagerType.kt b/...ct-native/ReactAndroid/src/main/java/com/facebook/react/uimanager/common/UIManagerType.kt
@@ -11,11 +11,15 @@ import androidx.annotation.IntDef
 import com.facebook.react.common.annotations.DeprecatedInNewArchitecture
 
 @Retention(AnnotationRetention.SOURCE)
-@IntDef(UIManagerType.DEFAULT, UIManagerType.FABRIC)
+@Suppress("DEPRECATION")
+@IntDef(UIManagerType.DEFAULT, UIManagerType.LEGACY, UIManagerType.FABRIC)
 @DeprecatedInNewArchitecture
 public annotation class UIManagerType {
   public companion object {
+    @Deprecated(
+        "UIManagerType.DEFAULT will be deleted in the next release of React Native. Use [LEGACY] instead.")
     public const val DEFAULT: Int = 1
+    public const val LEGACY: Int = 1
     public const val FABRIC: Int = 2
   }
 }
diff --git a/...s/react-native/ReactAndroid/src/main/java/com/facebook/react/uimanager/common/ViewUtil.kt b/...s/react-native/ReactAndroid/src/main/java/com/facebook/react/uimanager/common/ViewUtil.kt
@@ -25,7 +25,7 @@ public object ViewUtil {
       if (viewTag % 2 == 0) {
         UIManagerType.FABRIC
       } else {
-        UIManagerType.DEFAULT
+        UIManagerType.LEGACY
       }
 
   /**
@@ -55,8 +55,8 @@ public object ViewUtil {
     // by RN and is essentially a random number.
     // At some point it would be great to pass the SurfaceContext here instead.
     @UIManagerType
-    val uiManagerType = if (surfaceId == -1) UIManagerType.DEFAULT else UIManagerType.FABRIC
-    if (uiManagerType == UIManagerType.DEFAULT && !isRootTag(viewTag)) {
+    val uiManagerType = if (surfaceId == -1) UIManagerType.LEGACY else UIManagerType.FABRIC
+    if (uiManagerType == UIManagerType.LEGACY && !isRootTag(viewTag)) {
       // TODO (T123064648): Some events for Fabric still didn't have the surfaceId set, so if it's
       // not a React RootView, double check if the tag belongs to Fabric.
       if (viewTag % 2 == 0) {