Back out "Unify feature flags for event loop" (facebook#47041)

Summary:
Pull Request resolved: facebook#47041

Original commit changeset: b879447def8a

Original Phabricator Diff: D64175216

Reviewed By: fkgozali

Differential Revision: D64439014

packages/react-native/Libraries/AppDelegate/RCTAppDelegate.mm

@@ -307,6 +307,18 @@ - (RCTRootViewFactory *)createRCTRootViewFactory
 
 class RCTAppDelegateBridgelessFeatureFlags : public facebook::react::ReactNativeFeatureFlagsDefaults {
  public:
+  bool useModernRuntimeScheduler() override
+  {
+    return true;
+  }
+  bool enableMicrotasks() override
+  {
+    return true;
+  }
+  bool batchRenderingUpdatesInEventLoop() override
+  {
+    return true;
+  }
   bool enableBridgelessArchitecture() override
   {
     return true;

packages/react-native/Libraries/Core/setUpTimers.js

@@ -48,7 +48,12 @@ if (global.RN$Bridgeless !== true) {
   defineLazyTimer('cancelAnimationFrame');
   defineLazyTimer('requestIdleCallback');
   defineLazyTimer('cancelIdleCallback');
-} else if (!ReactNativeFeatureFlags.disableEventLoopOnBridgeless()) {
+} else if (
+  // TODO remove this condition when bridgeless == modern scheduler everywhere.
+  NativeReactNativeFeatureFlags != null &&
+  // eslint-disable-next-line react-hooks/rules-of-hooks -- false positive due to `use` prefix
+  ReactNativeFeatureFlags.useModernRuntimeScheduler()
+) {
   polyfillGlobal(
     'requestIdleCallback',
     () =>
@@ -64,9 +69,12 @@ if (global.RN$Bridgeless !== true) {
   );
 }
 
+// We need to check if the native module is available before accessing the
+// feature flag, because otherwise the API would throw an error in the legacy
+// architecture in OSS, where the native module isn't available.
 if (
-  global.RN$Bridgeless === true &&
-  !ReactNativeFeatureFlags.disableEventLoopOnBridgeless()
+  NativeReactNativeFeatureFlags != null &&
+  ReactNativeFeatureFlags.enableMicrotasks()
 ) {
   // This is the flag that tells React to use `queueMicrotask` to batch state
   // updates, instead of using the scheduler to schedule a regular 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<<4826cc8f70f03ef058fccfc4a6f282ae>>
+ * @generated SignedSource<<af80868112a7748983aaa6e638d0068e>>
  */
 
 /**
@@ -41,16 +41,16 @@ public object ReactNativeFeatureFlags {
   public fun allowRecursiveCommitsWithSynchronousMountOnAndroid(): Boolean = accessor.allowRecursiveCommitsWithSynchronousMountOnAndroid()
 
   /**
-   * Do not wait for a main-thread dispatch to complete init to start executing work on the JS thread on Android
+   * When enabled, the RuntimeScheduler processing the event loop will batch all rendering updates and dispatch them together at the end of each iteration of the loop.
    */
   @JvmStatic
-  public fun completeReactInstanceCreationOnBgThreadOnAndroid(): Boolean = accessor.completeReactInstanceCreationOnBgThreadOnAndroid()
+  public fun batchRenderingUpdatesInEventLoop(): Boolean = accessor.batchRenderingUpdatesInEventLoop()
 
   /**
-   * The bridgeless architecture enables the event loop by default. This feature flag allows us to force disabling it in specific instances.
+   * Do not wait for a main-thread dispatch to complete init to start executing work on the JS thread on Android
    */
   @JvmStatic
-  public fun disableEventLoopOnBridgeless(): Boolean = accessor.disableEventLoopOnBridgeless()
+  public fun completeReactInstanceCreationOnBgThreadOnAndroid(): Boolean = accessor.completeReactInstanceCreationOnBgThreadOnAndroid()
 
   /**
    * Kill-switch to turn off support for aling-items:baseline on Fabric iOS.
@@ -142,6 +142,12 @@ public object ReactNativeFeatureFlags {
   @JvmStatic
   public fun enableLongTaskAPI(): Boolean = accessor.enableLongTaskAPI()
 
+  /**
+   * Enables the use of microtasks in Hermes (scheduling) and RuntimeScheduler (execution).
+   */
+  @JvmStatic
+  public fun enableMicrotasks(): Boolean = accessor.enableMicrotasks()
+
   /**
    * Moves execution of pre-mount items to outside the choregrapher in the main thread, so we can estimate idle time more precisely (Android only).
    */
@@ -268,6 +274,12 @@ public object ReactNativeFeatureFlags {
   @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.
+   */
+  @JvmStatic
+  public fun useModernRuntimeScheduler(): Boolean = accessor.useModernRuntimeScheduler()
+
   /**
    * When enabled, the native view configs are used in bridgeless mode.
    */

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<<c1299f04cde6bff791f355e12ccf4df8>>
+ * @generated SignedSource<<b0a0f792ea56ce65a44de3ce90ec72ee>>
  */
 
 /**
@@ -22,8 +22,8 @@ package com.facebook.react.internal.featureflags
 public class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAccessor {
   private var commonTestFlagCache: Boolean? = null
   private var allowRecursiveCommitsWithSynchronousMountOnAndroidCache: Boolean? = null
+  private var batchRenderingUpdatesInEventLoopCache: Boolean? = null
   private var completeReactInstanceCreationOnBgThreadOnAndroidCache: Boolean? = null
-  private var disableEventLoopOnBridgelessCache: Boolean? = null
   private var enableAlignItemsBaselineOnFabricIOSCache: Boolean? = null
   private var enableAndroidLineHeightCenteringCache: Boolean? = null
   private var enableBridgelessArchitectureCache: Boolean? = null
@@ -39,6 +39,7 @@ public class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAccesso
   private var enableLayoutAnimationsOnAndroidCache: Boolean? = null
   private var enableLayoutAnimationsOnIOSCache: Boolean? = null
   private var enableLongTaskAPICache: Boolean? = null
+  private var enableMicrotasksCache: Boolean? = null
   private var enablePreciseSchedulingForPremountItemsOnAndroidCache: Boolean? = null
   private var enablePropsUpdateReconciliationAndroidCache: Boolean? = null
   private var enableReportEventPaintTimeCache: Boolean? = null
@@ -60,6 +61,7 @@ public class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAccesso
   private var traceTurboModulePromiseRejectionsOnAndroidCache: Boolean? = null
   private var useFabricInteropCache: Boolean? = null
   private var useImmediateExecutorInAndroidBridgelessCache: Boolean? = null
+  private var useModernRuntimeSchedulerCache: Boolean? = null
   private var useNativeViewConfigsInBridgelessModeCache: Boolean? = null
   private var useOptimisedViewPreallocationOnAndroidCache: Boolean? = null
   private var useOptimizedEventBatchingOnAndroidCache: Boolean? = null
@@ -85,20 +87,20 @@ public class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAccesso
     return cached
   }
 
-  override fun completeReactInstanceCreationOnBgThreadOnAndroid(): Boolean {
-    var cached = completeReactInstanceCreationOnBgThreadOnAndroidCache
+  override fun batchRenderingUpdatesInEventLoop(): Boolean {
+    var cached = batchRenderingUpdatesInEventLoopCache
     if (cached == null) {
-      cached = ReactNativeFeatureFlagsCxxInterop.completeReactInstanceCreationOnBgThreadOnAndroid()
-      completeReactInstanceCreationOnBgThreadOnAndroidCache = cached
+      cached = ReactNativeFeatureFlagsCxxInterop.batchRenderingUpdatesInEventLoop()
+      batchRenderingUpdatesInEventLoopCache = cached
     }
     return cached
   }
 
-  override fun disableEventLoopOnBridgeless(): Boolean {
-    var cached = disableEventLoopOnBridgelessCache
+  override fun completeReactInstanceCreationOnBgThreadOnAndroid(): Boolean {
+    var cached = completeReactInstanceCreationOnBgThreadOnAndroidCache
     if (cached == null) {
-      cached = ReactNativeFeatureFlagsCxxInterop.disableEventLoopOnBridgeless()
-      disableEventLoopOnBridgelessCache = cached
+      cached = ReactNativeFeatureFlagsCxxInterop.completeReactInstanceCreationOnBgThreadOnAndroid()
+      completeReactInstanceCreationOnBgThreadOnAndroidCache = cached
     }
     return cached
   }
@@ -238,6 +240,15 @@ public class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAccesso
     return cached
   }
 
+  override fun enableMicrotasks(): Boolean {
+    var cached = enableMicrotasksCache
+    if (cached == null) {
+      cached = ReactNativeFeatureFlagsCxxInterop.enableMicrotasks()
+      enableMicrotasksCache = cached
+    }
+    return cached
+  }
+
   override fun enablePreciseSchedulingForPremountItemsOnAndroid(): Boolean {
     var cached = enablePreciseSchedulingForPremountItemsOnAndroidCache
     if (cached == null) {
@@ -427,6 +438,15 @@ public class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAccesso
     return cached
   }
 
+  override fun useModernRuntimeScheduler(): Boolean {
+    var cached = useModernRuntimeSchedulerCache
+    if (cached == null) {
+      cached = ReactNativeFeatureFlagsCxxInterop.useModernRuntimeScheduler()
+      useModernRuntimeSchedulerCache = cached
+    }
+    return cached
+  }
+
   override fun useNativeViewConfigsInBridgelessMode(): Boolean {
     var cached = useNativeViewConfigsInBridgelessModeCache
     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<<579950bccf5b11ca473a0de01615756e>>
+ * @generated SignedSource<<2f1e29ca29c3679e5a87be1d0944efd9>>
  */
 
 /**
@@ -32,9 +32,9 @@ public object ReactNativeFeatureFlagsCxxInterop {
 
   @DoNotStrip @JvmStatic public external fun allowRecursiveCommitsWithSynchronousMountOnAndroid(): Boolean
 
-  @DoNotStrip @JvmStatic public external fun completeReactInstanceCreationOnBgThreadOnAndroid(): Boolean
+  @DoNotStrip @JvmStatic public external fun batchRenderingUpdatesInEventLoop(): Boolean
 
-  @DoNotStrip @JvmStatic public external fun disableEventLoopOnBridgeless(): Boolean
+  @DoNotStrip @JvmStatic public external fun completeReactInstanceCreationOnBgThreadOnAndroid(): Boolean
 
   @DoNotStrip @JvmStatic public external fun enableAlignItemsBaselineOnFabricIOS(): Boolean
 
@@ -66,6 +66,8 @@ public object ReactNativeFeatureFlagsCxxInterop {
 
   @DoNotStrip @JvmStatic public external fun enableLongTaskAPI(): Boolean
 
+  @DoNotStrip @JvmStatic public external fun enableMicrotasks(): Boolean
+
   @DoNotStrip @JvmStatic public external fun enablePreciseSchedulingForPremountItemsOnAndroid(): Boolean
 
   @DoNotStrip @JvmStatic public external fun enablePropsUpdateReconciliationAndroid(): Boolean
@@ -108,6 +110,8 @@ public object ReactNativeFeatureFlagsCxxInterop {
 
   @DoNotStrip @JvmStatic public external fun useImmediateExecutorInAndroidBridgeless(): Boolean
 
+  @DoNotStrip @JvmStatic public external fun useModernRuntimeScheduler(): Boolean
+
   @DoNotStrip @JvmStatic public external fun useNativeViewConfigsInBridgelessMode(): Boolean
 
   @DoNotStrip @JvmStatic public external fun useOptimisedViewPreallocationOnAndroid(): 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<<45065c5d8f78528edc1665fb405860b8>>
+ * @generated SignedSource<<f99453feaef7994f46278d40af544771>>
  */
 
 /**
@@ -27,9 +27,9 @@ public open class ReactNativeFeatureFlagsDefaults : ReactNativeFeatureFlagsProvi
 
   override fun allowRecursiveCommitsWithSynchronousMountOnAndroid(): Boolean = false
 
-  override fun completeReactInstanceCreationOnBgThreadOnAndroid(): Boolean = false
+  override fun batchRenderingUpdatesInEventLoop(): Boolean = false
 
-  override fun disableEventLoopOnBridgeless(): Boolean = false
+  override fun completeReactInstanceCreationOnBgThreadOnAndroid(): Boolean = false
 
   override fun enableAlignItemsBaselineOnFabricIOS(): Boolean = true
 
@@ -61,6 +61,8 @@ public open class ReactNativeFeatureFlagsDefaults : ReactNativeFeatureFlagsProvi
 
   override fun enableLongTaskAPI(): Boolean = false
 
+  override fun enableMicrotasks(): Boolean = false
+
   override fun enablePreciseSchedulingForPremountItemsOnAndroid(): Boolean = false
 
   override fun enablePropsUpdateReconciliationAndroid(): Boolean = false
@@ -103,6 +105,8 @@ public open class ReactNativeFeatureFlagsDefaults : ReactNativeFeatureFlagsProvi
 
   override fun useImmediateExecutorInAndroidBridgeless(): Boolean = false
 
+  override fun useModernRuntimeScheduler(): Boolean = false
+
   override fun useNativeViewConfigsInBridgelessMode(): Boolean = false
 
   override fun useOptimisedViewPreallocationOnAndroid(): 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<<f90aa7d0ec4bf99554ffca7acdf35369>>
+ * @generated SignedSource<<fb7bda2b8430d77435141daed4190e4a>>
  */
 
 /**
@@ -26,8 +26,8 @@ public class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcces
 
   private var commonTestFlagCache: Boolean? = null
   private var allowRecursiveCommitsWithSynchronousMountOnAndroidCache: Boolean? = null
+  private var batchRenderingUpdatesInEventLoopCache: Boolean? = null
   private var completeReactInstanceCreationOnBgThreadOnAndroidCache: Boolean? = null
-  private var disableEventLoopOnBridgelessCache: Boolean? = null
   private var enableAlignItemsBaselineOnFabricIOSCache: Boolean? = null
   private var enableAndroidLineHeightCenteringCache: Boolean? = null
   private var enableBridgelessArchitectureCache: Boolean? = null
@@ -43,6 +43,7 @@ public class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcces
   private var enableLayoutAnimationsOnAndroidCache: Boolean? = null
   private var enableLayoutAnimationsOnIOSCache: Boolean? = null
   private var enableLongTaskAPICache: Boolean? = null
+  private var enableMicrotasksCache: Boolean? = null
   private var enablePreciseSchedulingForPremountItemsOnAndroidCache: Boolean? = null
   private var enablePropsUpdateReconciliationAndroidCache: Boolean? = null
   private var enableReportEventPaintTimeCache: Boolean? = null
@@ -64,6 +65,7 @@ public class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcces
   private var traceTurboModulePromiseRejectionsOnAndroidCache: Boolean? = null
   private var useFabricInteropCache: Boolean? = null
   private var useImmediateExecutorInAndroidBridgelessCache: Boolean? = null
+  private var useModernRuntimeSchedulerCache: Boolean? = null
   private var useNativeViewConfigsInBridgelessModeCache: Boolean? = null
   private var useOptimisedViewPreallocationOnAndroidCache: Boolean? = null
   private var useOptimizedEventBatchingOnAndroidCache: Boolean? = null
@@ -91,22 +93,22 @@ public class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcces
     return cached
   }
 
-  override fun completeReactInstanceCreationOnBgThreadOnAndroid(): Boolean {
-    var cached = completeReactInstanceCreationOnBgThreadOnAndroidCache
+  override fun batchRenderingUpdatesInEventLoop(): Boolean {
+    var cached = batchRenderingUpdatesInEventLoopCache
     if (cached == null) {
-      cached = currentProvider.completeReactInstanceCreationOnBgThreadOnAndroid()
-      accessedFeatureFlags.add("completeReactInstanceCreationOnBgThreadOnAndroid")
-      completeReactInstanceCreationOnBgThreadOnAndroidCache = cached
+      cached = currentProvider.batchRenderingUpdatesInEventLoop()
+      accessedFeatureFlags.add("batchRenderingUpdatesInEventLoop")
+      batchRenderingUpdatesInEventLoopCache = cached
     }
     return cached
   }
 
-  override fun disableEventLoopOnBridgeless(): Boolean {
-    var cached = disableEventLoopOnBridgelessCache
+  override fun completeReactInstanceCreationOnBgThreadOnAndroid(): Boolean {
+    var cached = completeReactInstanceCreationOnBgThreadOnAndroidCache
     if (cached == null) {
-      cached = currentProvider.disableEventLoopOnBridgeless()
-      accessedFeatureFlags.add("disableEventLoopOnBridgeless")
-      disableEventLoopOnBridgelessCache = cached
+      cached = currentProvider.completeReactInstanceCreationOnBgThreadOnAndroid()
+      accessedFeatureFlags.add("completeReactInstanceCreationOnBgThreadOnAndroid")
+      completeReactInstanceCreationOnBgThreadOnAndroidCache = cached
     }
     return cached
   }
@@ -261,6 +263,16 @@ public class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcces
     return cached
   }
 
+  override fun enableMicrotasks(): Boolean {
+    var cached = enableMicrotasksCache
+    if (cached == null) {
+      cached = currentProvider.enableMicrotasks()
+      accessedFeatureFlags.add("enableMicrotasks")
+      enableMicrotasksCache = cached
+    }
+    return cached
+  }
+
   override fun enablePreciseSchedulingForPremountItemsOnAndroid(): Boolean {
     var cached = enablePreciseSchedulingForPremountItemsOnAndroidCache
     if (cached == null) {
@@ -471,6 +483,16 @@ public class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcces
     return cached
   }
 
+  override fun useModernRuntimeScheduler(): Boolean {
+    var cached = useModernRuntimeSchedulerCache
+    if (cached == null) {
+      cached = currentProvider.useModernRuntimeScheduler()
+      accessedFeatureFlags.add("useModernRuntimeScheduler")
+      useModernRuntimeSchedulerCache = cached
+    }
+    return cached
+  }
+
   override fun useNativeViewConfigsInBridgelessMode(): Boolean {
     var cached = useNativeViewConfigsInBridgelessModeCache
     if (cached == null) {