Introduce feature flag for safer main queue sync dispatch

Summary:
Gating for "safer main queue sync dispatch": D74769326

Changelog: [Internal]

Differential Revision: D74940621

Author: RSNara

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<<e9a109fd77667dd0cb945ef6ef9737f2>>
+ * @generated SignedSource<<29fc8306d84a015708ae3b7cdc2b3fa6>>
  */
 
 /**
@@ -252,6 +252,12 @@ public object ReactNativeFeatureFlags {
   @JvmStatic
   public fun incorporateMaxLinesDuringAndroidLayout(): Boolean = accessor.incorporateMaxLinesDuringAndroidLayout()
 
+  /**
+   * Main queue sync dispatch that won't deadlock with sync render/events
+   */
+  @JvmStatic
+  public fun saferMainQueueSyncDispatch(): Boolean = accessor.saferMainQueueSyncDispatch()
+
   /**
    * Enables storing js caller stack when creating promise in native module. This is useful in case of Promise rejection and tracing the cause.
    */

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<<1a5cd689229d4e0c31070123045e84da>>
+ * @generated SignedSource<<2b8cd50c252f01a177bd8e6aadb801e8>>
  */
 
 /**
@@ -57,6 +57,7 @@ internal class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAcces
   private var fuseboxEnabledReleaseCache: Boolean? = null
   private var fuseboxNetworkInspectionEnabledCache: Boolean? = null
   private var incorporateMaxLinesDuringAndroidLayoutCache: Boolean? = null
+  private var saferMainQueueSyncDispatchCache: Boolean? = null
   private var traceTurboModulePromiseRejectionsOnAndroidCache: Boolean? = null
   private var updateRuntimeShadowNodeReferencesOnCommitCache: Boolean? = null
   private var useAlwaysAvailableJSErrorHandlingCache: Boolean? = null
@@ -402,6 +403,15 @@ internal class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAcces
     return cached
   }
 
+  override fun saferMainQueueSyncDispatch(): Boolean {
+    var cached = saferMainQueueSyncDispatchCache
+    if (cached == null) {
+      cached = ReactNativeFeatureFlagsCxxInterop.saferMainQueueSyncDispatch()
+      saferMainQueueSyncDispatchCache = cached
+    }
+    return cached
+  }
+
   override fun traceTurboModulePromiseRejectionsOnAndroid(): Boolean {
     var cached = traceTurboModulePromiseRejectionsOnAndroidCache
     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<<c39d0c1834797b3309b4fc5ce814280c>>
+ * @generated SignedSource<<2965b940a2c335ca4d71aceb00f853bd>>
  */
 
 /**
@@ -102,6 +102,8 @@ public object ReactNativeFeatureFlagsCxxInterop {
 
   @DoNotStrip @JvmStatic public external fun incorporateMaxLinesDuringAndroidLayout(): Boolean
 
+  @DoNotStrip @JvmStatic public external fun saferMainQueueSyncDispatch(): Boolean
+
   @DoNotStrip @JvmStatic public external fun traceTurboModulePromiseRejectionsOnAndroid(): Boolean
 
   @DoNotStrip @JvmStatic public external fun updateRuntimeShadowNodeReferencesOnCommit(): 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<<7f357475254104729cc7910c14e1c1fb>>
+ * @generated SignedSource<<513bc3cc259131f9957f220b6847373e>>
  */
 
 /**
@@ -97,6 +97,8 @@ public open class ReactNativeFeatureFlagsDefaults : ReactNativeFeatureFlagsProvi
 
   override fun incorporateMaxLinesDuringAndroidLayout(): Boolean = true
 
+  override fun saferMainQueueSyncDispatch(): Boolean = false
+
   override fun traceTurboModulePromiseRejectionsOnAndroid(): Boolean = false
 
   override fun updateRuntimeShadowNodeReferencesOnCommit(): 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<<14cd1a58bd153dedda045a72c1494caa>>
+ * @generated SignedSource<<4022c8d62266f4bcc649022d1be2d7fe>>
  */
 
 /**
@@ -61,6 +61,7 @@ internal class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcc
   private var fuseboxEnabledReleaseCache: Boolean? = null
   private var fuseboxNetworkInspectionEnabledCache: Boolean? = null
   private var incorporateMaxLinesDuringAndroidLayoutCache: Boolean? = null
+  private var saferMainQueueSyncDispatchCache: Boolean? = null
   private var traceTurboModulePromiseRejectionsOnAndroidCache: Boolean? = null
   private var updateRuntimeShadowNodeReferencesOnCommitCache: Boolean? = null
   private var useAlwaysAvailableJSErrorHandlingCache: Boolean? = null
@@ -443,6 +444,16 @@ internal class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcc
     return cached
   }
 
+  override fun saferMainQueueSyncDispatch(): Boolean {
+    var cached = saferMainQueueSyncDispatchCache
+    if (cached == null) {
+      cached = currentProvider.saferMainQueueSyncDispatch()
+      accessedFeatureFlags.add("saferMainQueueSyncDispatch")
+      saferMainQueueSyncDispatchCache = cached
+    }
+    return cached
+  }
+
   override fun traceTurboModulePromiseRejectionsOnAndroid(): Boolean {
     var cached = traceTurboModulePromiseRejectionsOnAndroidCache
     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<<593b1d64dc31038140032a6b0a439700>>
+ * @generated SignedSource<<d25fe7e78767e4088e6d541236953137>>
  */
 
 /**
@@ -97,6 +97,8 @@ public interface ReactNativeFeatureFlagsProvider {
 
   @DoNotStrip public fun incorporateMaxLinesDuringAndroidLayout(): Boolean
 
+  @DoNotStrip public fun saferMainQueueSyncDispatch(): Boolean
+
   @DoNotStrip public fun traceTurboModulePromiseRejectionsOnAndroid(): Boolean
 
   @DoNotStrip public fun updateRuntimeShadowNodeReferencesOnCommit(): Boolean

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<<d74dc8182a14fddbd7118149298515bd>>
+ * @generated SignedSource<<5fb05a9e1d08a9cc92d315154db3db08>>
  */
 
 /**
@@ -261,6 +261,12 @@ class ReactNativeFeatureFlagsJavaProvider
     return method(javaProvider_);
   }
 
+  bool saferMainQueueSyncDispatch() override {
+    static const auto method =
+        getReactNativeFeatureFlagsProviderJavaClass()->getMethod<jboolean()>("saferMainQueueSyncDispatch");
+    return method(javaProvider_);
+  }
+
   bool traceTurboModulePromiseRejectionsOnAndroid() override {
     static const auto method =
         getReactNativeFeatureFlagsProviderJavaClass()->getMethod<jboolean()>("traceTurboModulePromiseRejectionsOnAndroid");
@@ -516,6 +522,11 @@ bool JReactNativeFeatureFlagsCxxInterop::incorporateMaxLinesDuringAndroidLayout(
   return ReactNativeFeatureFlags::incorporateMaxLinesDuringAndroidLayout();
 }
 
+bool JReactNativeFeatureFlagsCxxInterop::saferMainQueueSyncDispatch(
+    facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop> /*unused*/) {
+  return ReactNativeFeatureFlags::saferMainQueueSyncDispatch();
+}
+
 bool JReactNativeFeatureFlagsCxxInterop::traceTurboModulePromiseRejectionsOnAndroid(
     facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop> /*unused*/) {
   return ReactNativeFeatureFlags::traceTurboModulePromiseRejectionsOnAndroid();
@@ -713,6 +724,9 @@ void JReactNativeFeatureFlagsCxxInterop::registerNatives() {
       makeNativeMethod(
         "incorporateMaxLinesDuringAndroidLayout",
         JReactNativeFeatureFlagsCxxInterop::incorporateMaxLinesDuringAndroidLayout),
+      makeNativeMethod(
+        "saferMainQueueSyncDispatch",
+        JReactNativeFeatureFlagsCxxInterop::saferMainQueueSyncDispatch),
       makeNativeMethod(
         "traceTurboModulePromiseRejectionsOnAndroid",
         JReactNativeFeatureFlagsCxxInterop::traceTurboModulePromiseRejectionsOnAndroid),

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<<a5ab0022f6a01bd6e929d36d9d87db10>>
+ * @generated SignedSource<<d09a95dbb9417485fc538fc329c4ebd9>>
  */
 
 /**
@@ -141,6 +141,9 @@ class JReactNativeFeatureFlagsCxxInterop
   static bool incorporateMaxLinesDuringAndroidLayout(
     facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop>);
 
+  static bool saferMainQueueSyncDispatch(
+    facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop>);
+
   static bool traceTurboModulePromiseRejectionsOnAndroid(
     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<<88fdbea2f97f628187164a47a9737da0>>
+ * @generated SignedSource<<27d178af8531a2726bef81d8bb0ccbb1>>
  */
 
 /**
@@ -174,6 +174,10 @@ bool ReactNativeFeatureFlags::incorporateMaxLinesDuringAndroidLayout() {
   return getAccessor().incorporateMaxLinesDuringAndroidLayout();
 }
 
+bool ReactNativeFeatureFlags::saferMainQueueSyncDispatch() {
+  return getAccessor().saferMainQueueSyncDispatch();
+}
+
 bool ReactNativeFeatureFlags::traceTurboModulePromiseRejectionsOnAndroid() {
   return getAccessor().traceTurboModulePromiseRejectionsOnAndroid();
 }

packages/react-native/ReactCommon/react/featureflags/ReactNativeFeatureFlags.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<<a4123bc6f44835c022a1a5238908674c>>
+ * @generated SignedSource<<a0756c45d8e968e76f5d36393840ca42>>
  */
 
 /**
@@ -224,6 +224,11 @@ class ReactNativeFeatureFlags {
    */
   RN_EXPORT static bool incorporateMaxLinesDuringAndroidLayout();
 
+  /**
+   * Main queue sync dispatch that won't deadlock with sync render/events
+   */
+  RN_EXPORT static bool saferMainQueueSyncDispatch();
+
   /**
    * Enables storing js caller stack when creating promise in native module. This is useful in case of Promise rejection and tracing the cause.
    */

packages/react-native/ReactCommon/react/featureflags/ReactNativeFeatureFlagsAccessor.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<<0c768a58bd488ed1f3061cb4c13ef78d>>
+ * @generated SignedSource<<0e5cf9a97bbd8675555bf2cb4c10cc08>>
  */
 
 /**
@@ -695,6 +695,24 @@ bool ReactNativeFeatureFlagsAccessor::incorporateMaxLinesDuringAndroidLayout() {
   return flagValue.value();
 }
 
+bool ReactNativeFeatureFlagsAccessor::saferMainQueueSyncDispatch() {
+  auto flagValue = saferMainQueueSyncDispatch_.load();
+
+  if (!flagValue.has_value()) {
+    // This block is not exclusive but it is not necessary.
+    // If multiple threads try to initialize the feature flag, we would only
+    // be accessing the provider multiple times but the end state of this
+    // instance and the returned flag value would be the same.
+
+    markFlagAsAccessed(37, "saferMainQueueSyncDispatch");
+
+    flagValue = currentProvider_->saferMainQueueSyncDispatch();
+    saferMainQueueSyncDispatch_ = flagValue;
+  }
+
+  return flagValue.value();
+}
+
 bool ReactNativeFeatureFlagsAccessor::traceTurboModulePromiseRejectionsOnAndroid() {
   auto flagValue = traceTurboModulePromiseRejectionsOnAndroid_.load();
 
@@ -704,7 +722,7 @@ bool ReactNativeFeatureFlagsAccessor::traceTurboModulePromiseRejectionsOnAndroid
     // be accessing the provider multiple times but the end state of this
     // instance and the returned flag value would be the same.
 
-    markFlagAsAccessed(37, "traceTurboModulePromiseRejectionsOnAndroid");
+    markFlagAsAccessed(38, "traceTurboModulePromiseRejectionsOnAndroid");
 
     flagValue = currentProvider_->traceTurboModulePromiseRejectionsOnAndroid();
     traceTurboModulePromiseRejectionsOnAndroid_ = flagValue;
@@ -722,7 +740,7 @@ bool ReactNativeFeatureFlagsAccessor::updateRuntimeShadowNodeReferencesOnCommit(
     // be accessing the provider multiple times but the end state of this
     // instance and the returned flag value would be the same.
 
-    markFlagAsAccessed(38, "updateRuntimeShadowNodeReferencesOnCommit");
+    markFlagAsAccessed(39, "updateRuntimeShadowNodeReferencesOnCommit");
 
     flagValue = currentProvider_->updateRuntimeShadowNodeReferencesOnCommit();
     updateRuntimeShadowNodeReferencesOnCommit_ = flagValue;
@@ -740,7 +758,7 @@ bool ReactNativeFeatureFlagsAccessor::useAlwaysAvailableJSErrorHandling() {
     // be accessing the provider multiple times but the end state of this
     // instance and the returned flag value would be the same.
 
-    markFlagAsAccessed(39, "useAlwaysAvailableJSErrorHandling");
+    markFlagAsAccessed(40, "useAlwaysAvailableJSErrorHandling");
 
     flagValue = currentProvider_->useAlwaysAvailableJSErrorHandling();
     useAlwaysAvailableJSErrorHandling_ = flagValue;
@@ -758,7 +776,7 @@ bool ReactNativeFeatureFlagsAccessor::useAndroidTextLayoutWidthDirectly() {
     // be accessing the provider multiple times but the end state of this
     // instance and the returned flag value would be the same.
 
-    markFlagAsAccessed(40, "useAndroidTextLayoutWidthDirectly");
+    markFlagAsAccessed(41, "useAndroidTextLayoutWidthDirectly");
 
     flagValue = currentProvider_->useAndroidTextLayoutWidthDirectly();
     useAndroidTextLayoutWidthDirectly_ = flagValue;
@@ -776,7 +794,7 @@ bool ReactNativeFeatureFlagsAccessor::useFabricInterop() {
     // be accessing the provider multiple times but the end state of this
     // instance and the returned flag value would be the same.
 
-    markFlagAsAccessed(41, "useFabricInterop");
+    markFlagAsAccessed(42, "useFabricInterop");
 
     flagValue = currentProvider_->useFabricInterop();
     useFabricInterop_ = flagValue;
@@ -794,7 +812,7 @@ bool ReactNativeFeatureFlagsAccessor::useNativeViewConfigsInBridgelessMode() {
     // be accessing the provider multiple times but the end state of this
     // instance and the returned flag value would be the same.
 
-    markFlagAsAccessed(42, "useNativeViewConfigsInBridgelessMode");
+    markFlagAsAccessed(43, "useNativeViewConfigsInBridgelessMode");
 
     flagValue = currentProvider_->useNativeViewConfigsInBridgelessMode();
     useNativeViewConfigsInBridgelessMode_ = flagValue;
@@ -812,7 +830,7 @@ bool ReactNativeFeatureFlagsAccessor::useOptimizedEventBatchingOnAndroid() {
     // be accessing the provider multiple times but the end state of this
     // instance and the returned flag value would be the same.
 
-    markFlagAsAccessed(43, "useOptimizedEventBatchingOnAndroid");
+    markFlagAsAccessed(44, "useOptimizedEventBatchingOnAndroid");
 
     flagValue = currentProvider_->useOptimizedEventBatchingOnAndroid();
     useOptimizedEventBatchingOnAndroid_ = flagValue;
@@ -830,7 +848,7 @@ bool ReactNativeFeatureFlagsAccessor::useRawPropsJsiValue() {
     // be accessing the provider multiple times but the end state of this
     // instance and the returned flag value would be the same.
 
-    markFlagAsAccessed(44, "useRawPropsJsiValue");
+    markFlagAsAccessed(45, "useRawPropsJsiValue");
 
     flagValue = currentProvider_->useRawPropsJsiValue();
     useRawPropsJsiValue_ = flagValue;
@@ -848,7 +866,7 @@ bool ReactNativeFeatureFlagsAccessor::useShadowNodeStateOnClone() {
     // be accessing the provider multiple times but the end state of this
     // instance and the returned flag value would be the same.
 
-    markFlagAsAccessed(45, "useShadowNodeStateOnClone");
+    markFlagAsAccessed(46, "useShadowNodeStateOnClone");
 
     flagValue = currentProvider_->useShadowNodeStateOnClone();
     useShadowNodeStateOnClone_ = flagValue;
@@ -866,7 +884,7 @@ bool ReactNativeFeatureFlagsAccessor::useTurboModuleInterop() {
     // be accessing the provider multiple times but the end state of this
     // instance and the returned flag value would be the same.
 
-    markFlagAsAccessed(46, "useTurboModuleInterop");
+    markFlagAsAccessed(47, "useTurboModuleInterop");
 
     flagValue = currentProvider_->useTurboModuleInterop();
     useTurboModuleInterop_ = flagValue;
@@ -884,7 +902,7 @@ bool ReactNativeFeatureFlagsAccessor::useTurboModules() {
     // be accessing the provider multiple times but the end state of this
     // instance and the returned flag value would be the same.
 
-    markFlagAsAccessed(47, "useTurboModules");
+    markFlagAsAccessed(48, "useTurboModules");
 
     flagValue = currentProvider_->useTurboModules();
     useTurboModules_ = flagValue;