Add experiment to bypass background executor in bridgeless

packages/react-native/ReactAndroid/api/ReactAndroid.api

@@ -3840,6 +3840,7 @@ public abstract interface class com/facebook/react/runtime/internal/bolts/Contin
 }
 
 public class com/facebook/react/runtime/internal/bolts/Task : com/facebook/react/interfaces/TaskInterface {
+	public static final field IMMEDIATE_EXECUTOR Ljava/util/concurrent/Executor;
 	public static final field UI_THREAD_EXECUTOR Ljava/util/concurrent/Executor;
 	public static fun call (Ljava/util/concurrent/Callable;)Lcom/facebook/react/runtime/internal/bolts/Task;
 	public static fun call (Ljava/util/concurrent/Callable;Ljava/util/concurrent/Executor;)Lcom/facebook/react/runtime/internal/bolts/Task;

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<<bc03d88b59af436b2db4f9048184a881>>
+ * @generated SignedSource<<177f05d7b2fadcfffa32cb5a7a21c76b>>
  */
 
 /**
@@ -136,6 +136,12 @@ public object ReactNativeFeatureFlags {
   @JvmStatic
   public fun setAndroidLayoutDirection(): Boolean = accessor.setAndroidLayoutDirection()
 
+  /**
+   * Invoke callbacks immediately on the ReactInstance rather than going through a background thread for synchronization
+   */
+  @JvmStatic
+  public fun useImmediateExecutorInAndroidBridgeless(): Boolean = accessor.useImmediateExecutorInAndroidBridgeless()
+
   /**
    * 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<<546c981f0b56bb022ad4e96e6a6ddb17>>
+ * @generated SignedSource<<492902f307361b8f7b7d42973561a3b4>>
  */
 
 /**
@@ -38,6 +38,7 @@ public class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAccesso
   private var lazyAnimationCallbacksCache: Boolean? = null
   private var preventDoubleTextMeasureCache: Boolean? = null
   private var setAndroidLayoutDirectionCache: Boolean? = null
+  private var useImmediateExecutorInAndroidBridgelessCache: Boolean? = null
   private var useModernRuntimeSchedulerCache: Boolean? = null
   private var useNativeViewConfigsInBridgelessModeCache: Boolean? = null
   private var useRuntimeShadowNodeReferenceUpdateCache: Boolean? = null
@@ -206,6 +207,15 @@ public class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAccesso
     return cached
   }
 
+  override fun useImmediateExecutorInAndroidBridgeless(): Boolean {
+    var cached = useImmediateExecutorInAndroidBridgelessCache
+    if (cached == null) {
+      cached = ReactNativeFeatureFlagsCxxInterop.useImmediateExecutorInAndroidBridgeless()
+      useImmediateExecutorInAndroidBridgelessCache = 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<<d3e722e1630002aee16eaf33b60c8a8f>>
+ * @generated SignedSource<<05bf91e1b2a64cdc48615137deec627a>>
  */
 
 /**
@@ -64,6 +64,8 @@ public object ReactNativeFeatureFlagsCxxInterop {
 
   @DoNotStrip @JvmStatic public external fun setAndroidLayoutDirection(): Boolean
 
+  @DoNotStrip @JvmStatic public external fun useImmediateExecutorInAndroidBridgeless(): 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<<8cb9343bf5aa9a7ec1940720ce253c5b>>
+ * @generated SignedSource<<7c95ebf976344317cd8904d71ea22fe5>>
  */
 
 /**
@@ -59,6 +59,8 @@ public open class ReactNativeFeatureFlagsDefaults : ReactNativeFeatureFlagsProvi
 
   override fun setAndroidLayoutDirection(): Boolean = false
 
+  override fun useImmediateExecutorInAndroidBridgeless(): 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<<3b6ad9b32518e319bb7d11da4eaa262c>>
+ * @generated SignedSource<<d23d2a5f44f2b2068dde9e85e5b1ce9f>>
  */
 
 /**
@@ -42,6 +42,7 @@ public class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcces
   private var lazyAnimationCallbacksCache: Boolean? = null
   private var preventDoubleTextMeasureCache: Boolean? = null
   private var setAndroidLayoutDirectionCache: Boolean? = null
+  private var useImmediateExecutorInAndroidBridgelessCache: Boolean? = null
   private var useModernRuntimeSchedulerCache: Boolean? = null
   private var useNativeViewConfigsInBridgelessModeCache: Boolean? = null
   private var useRuntimeShadowNodeReferenceUpdateCache: Boolean? = null
@@ -228,6 +229,16 @@ public class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcces
     return cached
   }
 
+  override fun useImmediateExecutorInAndroidBridgeless(): Boolean {
+    var cached = useImmediateExecutorInAndroidBridgelessCache
+    if (cached == null) {
+      cached = currentProvider.useImmediateExecutorInAndroidBridgeless()
+      accessedFeatureFlags.add("useImmediateExecutorInAndroidBridgeless")
+      useImmediateExecutorInAndroidBridgelessCache = 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<<af167f52f81a78ac200159717eb55e8e>>
+ * @generated SignedSource<<d84816a13ad49b6e1c69c968a8503385>>
  */
 
 /**
@@ -59,6 +59,8 @@ public interface ReactNativeFeatureFlagsProvider {
 
   @DoNotStrip public fun setAndroidLayoutDirection(): Boolean
 
+  @DoNotStrip public fun useImmediateExecutorInAndroidBridgeless(): Boolean
+
   @DoNotStrip public fun useModernRuntimeScheduler(): Boolean
 
   @DoNotStrip public fun useNativeViewConfigsInBridgelessMode(): Boolean

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

@@ -59,6 +59,7 @@
 import com.facebook.react.interfaces.TaskInterface;
 import com.facebook.react.interfaces.exceptionmanager.ReactJsExceptionHandler;
 import com.facebook.react.interfaces.fabric.ReactSurface;
+import com.facebook.react.internal.featureflags.ReactNativeFeatureFlags;
 import com.facebook.react.modules.appearance.AppearanceModule;
 import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler;
 import com.facebook.react.modules.core.DeviceEventManagerModule;
@@ -215,7 +216,8 @@ TaskInterface<Void> prerenderSurface(final ReactSurfaceImpl surface) {
         reactInstance -> {
           log(method, "Execute");
           reactInstance.prerenderSurface(surface);
-        });
+        },
+        mBGExecutor);
   }
 
   /**
@@ -235,7 +237,8 @@ TaskInterface<Void> startSurface(final ReactSurfaceImpl surface) {
         reactInstance -> {
           log(method, "Execute");
           reactInstance.startSurface(surface);
-        });
+        },
+        mBGExecutor);
   }
 
   /**
@@ -255,7 +258,8 @@ TaskInterface<Void> stopSurface(final ReactSurfaceImpl surface) {
             reactInstance -> {
               log(method, "Execute");
               reactInstance.stopSurface(surface);
-            })
+            },
+            mBGExecutor)
         .makeVoid();
   }
 
@@ -756,7 +760,8 @@ DefaultHardwareBackBtnHandler getDefaultBackButtonHandler() {
         reactInstance -> {
           log(method, "Execute");
           reactInstance.loadJSBundle(bundleLoader);
-        });
+        },
+        null);
   }
 
   /* package */ Task<Boolean> registerSegment(
@@ -771,7 +776,8 @@ DefaultHardwareBackBtnHandler getDefaultBackButtonHandler() {
           log(method, "Execute");
           reactInstance.registerSegment(segmentId, path);
           assertNotNull(callback).invoke();
-        });
+        },
+        null);
   }
 
   /* package */ void handleHostException(Exception e) {
@@ -800,7 +806,8 @@ DefaultHardwareBackBtnHandler getDefaultBackButtonHandler() {
         method,
         reactInstance -> {
           reactInstance.callFunctionOnModule(moduleName, methodName, args);
-        });
+        },
+        null);
   }
 
   /* package */ void attachSurface(ReactSurfaceImpl surface) {
@@ -852,8 +859,8 @@ public void removeBeforeDestroyListener(@NonNull Function0<Unit> onBeforeDestroy
     }
   }
 
-  /* package */ interface VeniceThenable<T> {
-    void then(T t);
+  private interface ReactInstanceCalback {
+    void then(ReactInstance reactInstance);
   }
 
   @ThreadConfined("ReactHost")
@@ -909,9 +916,18 @@ private void raiseSoftException(String method, String message, @Nullable Throwab
 
   /** Schedule work on a ReactInstance that is already created. */
   private Task<Boolean> callWithExistingReactInstance(
-      final String callingMethod, final VeniceThenable<ReactInstance> continuation) {
+      final String callingMethod,
+      final ReactInstanceCalback continuation,
+      @Nullable Executor executor) {
     final String method = "callWithExistingReactInstance(" + callingMethod + ")";
 
+    if (executor == null) {
+      executor =
+          ReactNativeFeatureFlags.useImmediateExecutorInAndroidBridgeless()
+              ? Task.IMMEDIATE_EXECUTOR
+              : mBGExecutor;
+    }
+
     return mReactInstanceTaskRef
         .get()
         .onSuccess(
@@ -925,14 +941,23 @@ private Task<Boolean> callWithExistingReactInstance(
               continuation.then(reactInstance);
               return TRUE;
             },
-            mBGExecutor);
+            executor);
   }
 
   /** Create a ReactInstance if it doesn't exist already, and schedule work on it. */
   private Task<Void> callAfterGetOrCreateReactInstance(
-      final String callingMethod, final VeniceThenable<ReactInstance> runnable) {
+      final String callingMethod,
+      final ReactInstanceCalback runnable,
+      @Nullable Executor executor) {
     final String method = "callAfterGetOrCreateReactInstance(" + callingMethod + ")";
 
+    if (executor == null) {
+      executor =
+          ReactNativeFeatureFlags.useImmediateExecutorInAndroidBridgeless()
+              ? Task.IMMEDIATE_EXECUTOR
+              : mBGExecutor;
+    }
+
     return getOrCreateReactInstance()
         .onSuccess(
             task -> {
@@ -945,15 +970,14 @@ private Task<Void> callAfterGetOrCreateReactInstance(
               runnable.then(reactInstance);
               return null;
             },
-            mBGExecutor)
+            executor)
         .continueWith(
             task -> {
               if (task.isFaulted()) {
                 handleHostException(task.getError());
               }
               return null;
-            },
-            mBGExecutor);
+            });
   }
 
   private BridgelessReactContext getOrCreateReactContext() {

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

@@ -369,6 +369,7 @@ public Collection<NativeModule> getNativeModules() {
     }
   }
 
+  @ThreadConfined("ReactHost")
   /* package */ void prerenderSurface(ReactSurfaceImpl surface) {
     Systrace.beginSection(Systrace.TRACE_TAG_REACT_JAVA_BRIDGE, "ReactInstance.prerenderSurface");
     FLog.d(TAG, "call prerenderSurface with surface: " + surface.getModuleName());

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/runtime/internal/bolts/Task.java

@@ -27,7 +27,7 @@ public class Task<TResult> implements TaskInterface<TResult> {
    * stack runs too deep, at which point it will delegate to {@link Task#BACKGROUND_EXECUTOR} in
    * order to trim the stack.
    */
-  private static final Executor IMMEDIATE_EXECUTOR = Executors.IMMEDIATE;
+  public static final Executor IMMEDIATE_EXECUTOR = Executors.IMMEDIATE;
 
   /** An {@link java.util.concurrent.Executor} that executes tasks on the UI thread. */
   public static final Executor UI_THREAD_EXECUTOR = Executors.UI_THREAD;

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<<43b256d5f58743df52f579dc69721083>>
+ * @generated SignedSource<<2af7a8ae4860f81b46e48afb17ee54b6>>
  */
 
 /**
@@ -147,6 +147,12 @@ class ReactNativeFeatureFlagsProviderHolder
     return method(javaProvider_);
   }
 
+  bool useImmediateExecutorInAndroidBridgeless() override {
+    static const auto method =
+        getReactNativeFeatureFlagsProviderJavaClass()->getMethod<jboolean()>("useImmediateExecutorInAndroidBridgeless");
+    return method(javaProvider_);
+  }
+
   bool useModernRuntimeScheduler() override {
     static const auto method =
         getReactNativeFeatureFlagsProviderJavaClass()->getMethod<jboolean()>("useModernRuntimeScheduler");
@@ -271,6 +277,11 @@ bool JReactNativeFeatureFlagsCxxInterop::setAndroidLayoutDirection(
   return ReactNativeFeatureFlags::setAndroidLayoutDirection();
 }
 
+bool JReactNativeFeatureFlagsCxxInterop::useImmediateExecutorInAndroidBridgeless(
+    facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop> /*unused*/) {
+  return ReactNativeFeatureFlags::useImmediateExecutorInAndroidBridgeless();
+}
+
 bool JReactNativeFeatureFlagsCxxInterop::useModernRuntimeScheduler(
     facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop> /*unused*/) {
   return ReactNativeFeatureFlags::useModernRuntimeScheduler();
@@ -367,6 +378,9 @@ void JReactNativeFeatureFlagsCxxInterop::registerNatives() {
       makeNativeMethod(
         "setAndroidLayoutDirection",
         JReactNativeFeatureFlagsCxxInterop::setAndroidLayoutDirection),
+      makeNativeMethod(
+        "useImmediateExecutorInAndroidBridgeless",
+        JReactNativeFeatureFlagsCxxInterop::useImmediateExecutorInAndroidBridgeless),
       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<<19fe3642ec462c23d361e0f036da887a>>
+ * @generated SignedSource<<1d1422d073ae40ee4bbc788dc222cc28>>
  */
 
 /**
@@ -84,6 +84,9 @@ class JReactNativeFeatureFlagsCxxInterop
   static bool setAndroidLayoutDirection(
     facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop>);
 
+  static bool useImmediateExecutorInAndroidBridgeless(
+    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<<b7969efd5890b7be7be5fd8e6b0bf301>>
+ * @generated SignedSource<<ec12fd62d1dc2109e52a95094d7ad167>>
  */
 
 /**
@@ -93,6 +93,10 @@ bool ReactNativeFeatureFlags::setAndroidLayoutDirection() {
   return getAccessor().setAndroidLayoutDirection();
 }
 
+bool ReactNativeFeatureFlags::useImmediateExecutorInAndroidBridgeless() {
+  return getAccessor().useImmediateExecutorInAndroidBridgeless();
+}
+
 bool ReactNativeFeatureFlags::useModernRuntimeScheduler() {
   return getAccessor().useModernRuntimeScheduler();
 }