ScrollView: Delete unstable_setEnableSyncOnScroll (#47399)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/47399

Deletes `unstable_setEnableSyncOnScroll` which we are no longer experirmenting with in React Native.

Changelog:
[Internal] - Deleted `unstable_setEnableSyncOnScroll` on `ScrollView`, which was never part of the React Native Public API.

Reviewed By: tdn120, sammy-SC

Differential Revision: D65449039

fbshipit-source-id: 6608d5ccca477f1da5e0168c4a342cce17014b08

packages/react-native/Libraries/Components/ScrollView/AndroidHorizontalScrollViewNativeComponent.js

@@ -31,7 +31,6 @@ export const __INTERNAL_VIEW_CONFIG: PartialViewConfig = {
     pagingEnabled: true,
     persistentScrollbar: true,
     horizontal: true,
-    enableSyncOnScroll: true,
     scrollEnabled: true,
     scrollEventThrottle: true,
     scrollPerfTag: true,

packages/react-native/Libraries/Components/ScrollView/ScrollView.js

@@ -8,10 +8,6 @@
  * @flow strict-local
  */
 
-import type {
-  TScrollViewNativeComponentInstance,
-  TScrollViewNativeImperativeHandle,
-} from '../../../src/private/components/useSyncOnScroll';
 import type {HostInstance} from '../../Renderer/shims/ReactNativeTypes';
 import type {EdgeInsetsProp} from '../../StyleSheet/EdgeInsetsPropType';
 import type {PointProp} from '../../StyleSheet/PointPropType';
@@ -46,7 +42,6 @@ import StyleSheet from '../../StyleSheet/StyleSheet';
 import Dimensions from '../../Utilities/Dimensions';
 import dismissKeyboard from '../../Utilities/dismissKeyboard';
 import Platform from '../../Utilities/Platform';
-import EventEmitter from '../../vendor/emitter/EventEmitter';
 import Keyboard from '../Keyboard/Keyboard';
 import TextInputState from '../TextInput/TextInputState';
 import processDecelerationRate from './processDecelerationRate';
@@ -152,7 +147,7 @@ export type DecelerationRateType = 'fast' | 'normal' | number;
 export type ScrollResponderType = ScrollViewImperativeMethods;
 
 type PublicScrollViewInstance = $ReadOnly<{|
-  ...$Exact<TScrollViewNativeComponentInstance>,
+  ...HostInstance,
   ...ScrollViewImperativeMethods,
 |}>;
 
@@ -743,10 +738,6 @@ class ScrollView extends React.Component<Props, State> {
   _subscriptionKeyboardDidShow: ?EventSubscription = null;
   _subscriptionKeyboardDidHide: ?EventSubscription = null;
 
-  #onScrollEmitter: ?EventEmitter<{
-    scroll: [{x: number, y: number}],
-  }> = null;
-
   state: State = {
     layoutHeight: null,
   };
@@ -817,8 +808,6 @@ class ScrollView extends React.Component<Props, State> {
     if (this._scrollAnimatedValueAttachment) {
       this._scrollAnimatedValueAttachment.detach();
     }
-
-    this.#onScrollEmitter?.removeAllListeners();
   }
 
   /**
@@ -844,9 +833,8 @@ class ScrollView extends React.Component<Props, State> {
     return this._innerView.nativeInstance;
   };
 
-  getNativeScrollRef: () => TScrollViewNativeComponentInstance | null = () => {
-    const {nativeInstance} = this._scrollView;
-    return nativeInstance == null ? null : nativeInstance.componentRef.current;
+  getNativeScrollRef: () => HostInstance | null = () => {
+    return this._scrollView.nativeInstance;
   };
 
   /**
@@ -937,20 +925,6 @@ class ScrollView extends React.Component<Props, State> {
     Commands.flashScrollIndicators(component);
   };
 
-  _subscribeToOnScroll: (
-    callback: ({x: number, y: number}) => void,
-  ) => EventSubscription = callback => {
-    let onScrollEmitter = this.#onScrollEmitter;
-    if (onScrollEmitter == null) {
-      onScrollEmitter = new EventEmitter();
-      this.#onScrollEmitter = onScrollEmitter;
-      // This is the first subscription, so make sure the native component is
-      // also configured to output synchronous scroll events.
-      this._scrollView.nativeInstance?.unstable_setEnableSyncOnScroll(true);
-    }
-    return onScrollEmitter.addListener('scroll', callback);
-  };
-
   /**
    * This method should be used as the callback to onFocus in a TextInputs'
    * parent view. Note that any module using this mixin needs to return
@@ -1154,11 +1128,6 @@ class ScrollView extends React.Component<Props, State> {
   _handleScroll = (e: ScrollEvent) => {
     this._observedScrollSinceBecomingResponder = true;
     this.props.onScroll && this.props.onScroll(e);
-
-    this.#onScrollEmitter?.emit('scroll', {
-      x: e.nativeEvent.contentOffset.x,
-      y: e.nativeEvent.contentOffset.y,
-    });
   };
 
   _handleLayout = (e: LayoutEvent) => {
@@ -1181,45 +1150,36 @@ class ScrollView extends React.Component<Props, State> {
       (instance: InnerViewInstance): InnerViewInstance => instance,
     );
 
-  _scrollView: RefForwarder<
-    TScrollViewNativeImperativeHandle,
-    PublicScrollViewInstance | null,
-  > = createRefForwarder(nativeImperativeHandle => {
-    const nativeInstance = nativeImperativeHandle.componentRef.current;
-    if (nativeInstance == null) {
-      return null;
-    }
+  _scrollView: RefForwarder<HostInstance, PublicScrollViewInstance | null> =
+    createRefForwarder(nativeInstance => {
+      // This is a hack. Ideally we would forwardRef  to the underlying
+      // host component. However, since ScrollView has it's own methods that can be
+      // called as well, if we used the standard forwardRef then these
+      // methods wouldn't be accessible and thus be a breaking change.
+      //
+      // Therefore we edit ref to include ScrollView's public methods so that
+      // they are callable from the ref.
 
-    // This is a hack. Ideally we would forwardRef  to the underlying
-    // host component. However, since ScrollView has it's own methods that can be
-    // called as well, if we used the standard forwardRef then these
-    // methods wouldn't be accessible and thus be a breaking change.
-    //
-    // Therefore we edit ref to include ScrollView's public methods so that
-    // they are callable from the ref.
+      // $FlowFixMe[prop-missing] - Known issue with appending custom methods.
+      const publicInstance: PublicScrollViewInstance = Object.assign(
+        nativeInstance,
+        {
+          getScrollResponder: this.getScrollResponder,
+          getScrollableNode: this.getScrollableNode,
+          getInnerViewNode: this.getInnerViewNode,
+          getInnerViewRef: this.getInnerViewRef,
+          getNativeScrollRef: this.getNativeScrollRef,
+          scrollTo: this.scrollTo,
+          scrollToEnd: this.scrollToEnd,
+          flashScrollIndicators: this.flashScrollIndicators,
+          scrollResponderZoomTo: this.scrollResponderZoomTo,
+          scrollResponderScrollNativeHandleToKeyboard:
+            this.scrollResponderScrollNativeHandleToKeyboard,
+        },
+      );
 
-    // $FlowFixMe[prop-missing] - Known issue with appending custom methods.
-    const publicInstance: PublicScrollViewInstance = Object.assign(
-      nativeInstance,
-      {
-        getScrollResponder: this.getScrollResponder,
-        getScrollableNode: this.getScrollableNode,
-        getInnerViewNode: this.getInnerViewNode,
-        getInnerViewRef: this.getInnerViewRef,
-        getNativeScrollRef: this.getNativeScrollRef,
-        scrollTo: this.scrollTo,
-        scrollToEnd: this.scrollToEnd,
-        flashScrollIndicators: this.flashScrollIndicators,
-        scrollResponderZoomTo: this.scrollResponderZoomTo,
-        // TODO: Replace unstable_subscribeToOnScroll once scrollView.addEventListener('scroll', (e: ScrollEvent) => {}, {passive: false});
-        unstable_subscribeToOnScroll: this._subscribeToOnScroll,
-        scrollResponderScrollNativeHandleToKeyboard:
-          this.scrollResponderScrollNativeHandleToKeyboard,
-      },
-    );
-
-    return publicInstance;
-  });
+      return publicInstance;
+    });
 
   /**
    * Warning, this may be called several times for a single keyboard opening.
@@ -1829,8 +1789,9 @@ class ScrollView extends React.Component<Props, State> {
     }
 
     const refreshControl = this.props.refreshControl;
-    const scrollViewRef: React.RefSetter<TScrollViewNativeImperativeHandle | null> =
-      this._scrollView.getForwardingRef(this.props.scrollViewRef);
+    const scrollViewRef = this._scrollView.getForwardingRef(
+      this.props.scrollViewRef,
+    );
 
     if (refreshControl) {
       if (Platform.OS === 'ios') {

packages/react-native/Libraries/Components/ScrollView/ScrollViewNativeComponent.js

@@ -45,7 +45,6 @@ export const __INTERNAL_VIEW_CONFIG: PartialViewConfig =
             diff: require('../../Utilities/differ/pointsDiffer'),
           },
           decelerationRate: true,
-          enableSyncOnScroll: true, // Fabric only.
           disableIntervalMomentum: true,
           maintainVisibleContentPosition: true,
           pagingEnabled: true,
@@ -135,7 +134,6 @@ export const __INTERNAL_VIEW_CONFIG: PartialViewConfig =
           contentInsetAdjustmentBehavior: true,
           decelerationRate: true,
           endDraggingSensitivityMultiplier: true,
-          enableSyncOnScroll: true, // Fabric only.
           directionalLockEnabled: true,
           disableIntervalMomentum: true,
           indicatorStyle: true,

packages/react-native/Libraries/__tests__/__snapshots__/public-api-test.js.snap

@@ -2042,7 +2042,7 @@ exports[`public API should not change unintentionally Libraries/Components/Scrol
 export type DecelerationRateType = \\"fast\\" | \\"normal\\" | number;
 export type ScrollResponderType = ScrollViewImperativeMethods;
 type PublicScrollViewInstance = $ReadOnly<{|
-  ...$Exact<TScrollViewNativeComponentInstance>,
+  ...HostInstance,
   ...ScrollViewImperativeMethods,
 |}>;
 type InnerViewInstance = React.ElementRef<View>;
@@ -2169,7 +2169,7 @@ declare class ScrollView extends React.Component<Props, State> {
   getScrollableNode: () => ?number;
   getInnerViewNode: () => ?number;
   getInnerViewRef: () => InnerViewInstance | null;
-  getNativeScrollRef: () => TScrollViewNativeComponentInstance | null;
+  getNativeScrollRef: () => HostInstance | null;
   scrollTo: (
     options?:
       | {
@@ -2184,9 +2184,6 @@ declare class ScrollView extends React.Component<Props, State> {
   ) => void;
   scrollToEnd: (options?: ?{ animated?: boolean, ... }) => void;
   flashScrollIndicators: () => void;
-  _subscribeToOnScroll: (
-    callback: ({ x: number, y: number }) => void
-  ) => EventSubscription;
   scrollResponderScrollNativeHandleToKeyboard: (
     nodeHandle: number | HostInstance,
     additionalOffset?: number,
@@ -2224,10 +2221,7 @@ declare class ScrollView extends React.Component<Props, State> {
   _handleLayout: $FlowFixMe;
   _handleContentOnLayout: $FlowFixMe;
   _innerView: RefForwarder<InnerViewInstance, InnerViewInstance>;
-  _scrollView: RefForwarder<
-    TScrollViewNativeImperativeHandle,
-    PublicScrollViewInstance | null,
-  >;
+  _scrollView: RefForwarder<HostInstance, PublicScrollViewInstance | null>;
   scrollResponderKeyboardWillShow: (e: KeyboardEvent) => void;
   scrollResponderKeyboardWillHide: (e: KeyboardEvent) => void;
   scrollResponderKeyboardDidShow: (e: KeyboardEvent) => void;

packages/react-native/React/Fabric/Mounting/ComponentViews/ScrollView/RCTScrollViewComponentView.mm

@@ -618,31 +618,18 @@ static inline UIViewAnimationOptions animationOptionsWithCurve(UIViewAnimationCu
 
 - (void)scrollViewDidScroll:(UIScrollView *)scrollView
 {
-  const auto &props = static_cast<const ScrollViewProps &>(*_props);
   auto scrollMetrics = [self _scrollViewMetrics];
 
-  if (props.enableSyncOnScroll) {
+  [self _updateStateWithContentOffset];
+
+  NSTimeInterval now = CACurrentMediaTime();
+  if ((_lastScrollEventDispatchTime == 0) || (now - _lastScrollEventDispatchTime > _scrollEventThrottle)) {
+    _lastScrollEventDispatchTime = now;
     if (_eventEmitter) {
-      const auto &eventEmitter = static_cast<const ScrollViewEventEmitter &>(*_eventEmitter);
-      // TODO: temporary API to unblock testing of synchronous rendering.
-      eventEmitter.experimental_flushSync([&eventEmitter, &scrollMetrics, &self]() {
-        [self _updateStateWithContentOffset];
-        // TODO: temporary API to unblock testing of synchronous rendering.
-        eventEmitter.experimental_onDiscreteScroll(scrollMetrics);
-      });
+      static_cast<const ScrollViewEventEmitter &>(*_eventEmitter).onScroll(scrollMetrics);
     }
-  } else {
-    [self _updateStateWithContentOffset];
 
-    NSTimeInterval now = CACurrentMediaTime();
-    if ((_lastScrollEventDispatchTime == 0) || (now - _lastScrollEventDispatchTime > _scrollEventThrottle)) {
-      _lastScrollEventDispatchTime = now;
-      if (_eventEmitter) {
-        static_cast<const ScrollViewEventEmitter &>(*_eventEmitter).onScroll(scrollMetrics);
-      }
-
-      RCTSendScrollEventForNativeAnimations_DEPRECATED(scrollView, self.tag, kOnScrollEvent);
-    }
+    RCTSendScrollEventForNativeAnimations_DEPRECATED(scrollView, self.tag, kOnScrollEvent);
   }
 
   [self _remountChildrenIfNeeded];

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

@@ -6798,7 +6798,6 @@ public class com/facebook/react/views/scroll/ReactHorizontalScrollView : android
 	public fun setBorderWidth (IF)V
 	public fun setDecelerationRate (F)V
 	public fun setDisableIntervalMomentum (Z)V
-	public fun setEnableSyncOnScroll (Z)V
 	public fun setEndFillColor (I)V
 	public fun setLastScrollDispatchTime (J)V
 	public fun setMaintainVisibleContentPosition (Lcom/facebook/react/views/scroll/MaintainVisibleScrollPositionHelper$Config;)V
@@ -6846,7 +6845,6 @@ public class com/facebook/react/views/scroll/ReactHorizontalScrollViewManager :
 	public fun setContentOffset (Lcom/facebook/react/views/scroll/ReactHorizontalScrollView;Lcom/facebook/react/bridge/ReadableMap;)V
 	public fun setDecelerationRate (Lcom/facebook/react/views/scroll/ReactHorizontalScrollView;F)V
 	public fun setDisableIntervalMomentum (Lcom/facebook/react/views/scroll/ReactHorizontalScrollView;Z)V
-	public fun setEnableSyncOnScroll (Lcom/facebook/react/views/scroll/ReactHorizontalScrollView;Z)V
 	public fun setFadingEdgeLength (Lcom/facebook/react/views/scroll/ReactHorizontalScrollView;I)V
 	public fun setHorizontal (Lcom/facebook/react/views/scroll/ReactHorizontalScrollView;Z)V
 	public fun setMaintainVisibleContentPosition (Lcom/facebook/react/views/scroll/ReactHorizontalScrollView;Lcom/facebook/react/bridge/ReadableMap;)V
@@ -6921,7 +6919,6 @@ public class com/facebook/react/views/scroll/ReactScrollView : android/widget/Sc
 	public fun setContentOffset (Lcom/facebook/react/bridge/ReadableMap;)V
 	public fun setDecelerationRate (F)V
 	public fun setDisableIntervalMomentum (Z)V
-	public fun setEnableSyncOnScroll (Z)V
 	public fun setEndFillColor (I)V
 	public fun setLastScrollDispatchTime (J)V
 	public fun setMaintainVisibleContentPosition (Lcom/facebook/react/views/scroll/MaintainVisibleScrollPositionHelper$Config;)V
@@ -7003,7 +7000,6 @@ public final class com/facebook/react/views/scroll/ReactScrollViewHelper {
 	public static final fun updateFabricScrollState (Landroid/view/ViewGroup;)V
 	public final fun updateFabricScrollState (Landroid/view/ViewGroup;II)V
 	public static final fun updateStateOnScrollChanged (Landroid/view/ViewGroup;FF)V
-	public static final fun updateStateOnScrollChanged (Landroid/view/ViewGroup;FFZ)V
 }
 
 public abstract interface class com/facebook/react/views/scroll/ReactScrollViewHelper$HasFlingAnimator {
@@ -7086,7 +7082,6 @@ public class com/facebook/react/views/scroll/ReactScrollViewManager : com/facebo
 	public fun setContentOffset (Lcom/facebook/react/views/scroll/ReactScrollView;Lcom/facebook/react/bridge/ReadableMap;)V
 	public fun setDecelerationRate (Lcom/facebook/react/views/scroll/ReactScrollView;F)V
 	public fun setDisableIntervalMomentum (Lcom/facebook/react/views/scroll/ReactScrollView;Z)V
-	public fun setEnableSyncOnScroll (Lcom/facebook/react/views/scroll/ReactScrollView;Z)V
 	public fun setFadingEdgeLength (Lcom/facebook/react/views/scroll/ReactScrollView;I)V
 	public fun setHorizontal (Lcom/facebook/react/views/scroll/ReactScrollView;Z)V
 	public fun setIsInvertedVirtualizedList (Lcom/facebook/react/views/scroll/ReactScrollView;Z)V
@@ -7116,13 +7111,13 @@ public final class com/facebook/react/views/scroll/ScrollEvent : com/facebook/re
 	public static final field Companion Lcom/facebook/react/views/scroll/ScrollEvent$Companion;
 	public fun canCoalesce ()Z
 	public fun getEventName ()Ljava/lang/String;
-	public static final fun obtain (IILcom/facebook/react/views/scroll/ScrollEventType;FFFFIIIIZ)Lcom/facebook/react/views/scroll/ScrollEvent;
+	public static final fun obtain (IILcom/facebook/react/views/scroll/ScrollEventType;FFFFIIII)Lcom/facebook/react/views/scroll/ScrollEvent;
 	public static final fun obtain (ILcom/facebook/react/views/scroll/ScrollEventType;FFFFIIII)Lcom/facebook/react/views/scroll/ScrollEvent;
 	public fun onDispose ()V
 }
 
 public final class com/facebook/react/views/scroll/ScrollEvent$Companion {
-	public final fun obtain (IILcom/facebook/react/views/scroll/ScrollEventType;FFFFIIIIZ)Lcom/facebook/react/views/scroll/ScrollEvent;
+	public final fun obtain (IILcom/facebook/react/views/scroll/ScrollEventType;FFFFIIII)Lcom/facebook/react/views/scroll/ScrollEvent;
 	public final fun obtain (ILcom/facebook/react/views/scroll/ScrollEventType;FFFFIIII)Lcom/facebook/react/views/scroll/ScrollEvent;
 }
 

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactHorizontalScrollView.java

@@ -103,8 +103,6 @@ public class ReactHorizontalScrollView extends HorizontalScrollView
   private @Nullable Runnable mPostTouchRunnable;
   private boolean mRemoveClippedSubviews;
   private boolean mScrollEnabled = true;
-  private boolean mPreventReentry = false;
-  private boolean mEnableSyncOnScroll = false;
   private boolean mSendMomentumEvents;
   private @Nullable FpsListener mFpsListener = null;
   private @Nullable String mScrollPerfTag;
@@ -231,10 +229,6 @@ public class ReactHorizontalScrollView extends HorizontalScrollView
     mScrollEnabled = scrollEnabled;
   }
 
-  public void setEnableSyncOnScroll(boolean enableSyncOnScroll) {
-    mEnableSyncOnScroll = enableSyncOnScroll;
-  }
-
   public void setPagingEnabled(boolean pagingEnabled) {
     mPagingEnabled = pagingEnabled;
   }
@@ -492,16 +486,10 @@ public class ReactHorizontalScrollView extends HorizontalScrollView
         if (mRemoveClippedSubviews) {
           updateClippingRect();
         }
-        if (mPreventReentry) {
-          return;
-        }
-        mPreventReentry = true;
         ReactScrollViewHelper.updateStateOnScrollChanged(
             this,
             mOnScrollDispatchHelper.getXFlingVelocity(),
-            mOnScrollDispatchHelper.getYFlingVelocity(),
-            mEnableSyncOnScroll);
-        mPreventReentry = false;
+            mOnScrollDispatchHelper.getYFlingVelocity());
       }
     } finally {
       Systrace.endSection(Systrace.TRACE_TAG_REACT_JAVA_BRIDGE);

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactHorizontalScrollViewManager.java

@@ -95,11 +95,6 @@ public class ReactHorizontalScrollViewManager extends ViewGroupManager<ReactHori
     view.setDecelerationRate(decelerationRate);
   }
 
-  @ReactProp(name = "enableSyncOnScroll")
-  public void setEnableSyncOnScroll(ReactHorizontalScrollView view, boolean enableSyncOnScroll) {
-    view.setEnableSyncOnScroll(enableSyncOnScroll);
-  }
-
   @ReactProp(name = "disableIntervalMomentum")
   public void setDisableIntervalMomentum(
       ReactHorizontalScrollView view, boolean disableIntervalMomentum) {

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactScrollView.java

@@ -102,11 +102,9 @@ public class ReactScrollView extends ScrollView
   private @Nullable Runnable mPostTouchRunnable;
   private boolean mRemoveClippedSubviews;
   private boolean mScrollEnabled = true;
-  private boolean mPreventReentry = false;
   private boolean mSendMomentumEvents;
   private @Nullable FpsListener mFpsListener = null;
   private @Nullable String mScrollPerfTag;
-  private boolean mEnableSyncOnScroll = false;
   private @Nullable Drawable mEndBackground;
   private int mEndFillColor = Color.TRANSPARENT;
   private boolean mDisableIntervalMomentum = false;
@@ -210,10 +208,6 @@ public class ReactScrollView extends ScrollView
     mScrollPerfTag = scrollPerfTag;
   }
 
-  public void setEnableSyncOnScroll(boolean enableSyncOnScroll) {
-    mEnableSyncOnScroll = enableSyncOnScroll;
-  }
-
   public void setScrollEnabled(boolean scrollEnabled) {
     mScrollEnabled = scrollEnabled;
   }
@@ -418,16 +412,10 @@ public class ReactScrollView extends ScrollView
         if (mRemoveClippedSubviews) {
           updateClippingRect();
         }
-        if (mPreventReentry) {
-          return;
-        }
-        mPreventReentry = true;
         ReactScrollViewHelper.updateStateOnScrollChanged(
             this,
             mOnScrollDispatchHelper.getXFlingVelocity(),
-            mOnScrollDispatchHelper.getYFlingVelocity(),
-            mEnableSyncOnScroll);
-        mPreventReentry = false;
+            mOnScrollDispatchHelper.getYFlingVelocity());
       }
     } finally {
       Systrace.endSection(Systrace.TRACE_TAG_REACT_JAVA_BRIDGE);

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactScrollViewHelper.kt

@@ -103,7 +103,6 @@ public object ReactScrollViewHelper {
       scrollEventType: ScrollEventType,
       xVelocity: Float,
       yVelocity: Float,
-      experimental_isSynchronous: Boolean = false,
   ) where T : HasScrollEventThrottle?, T : ViewGroup {
     val now = System.currentTimeMillis()
     // Throttle the scroll event if scrollEventThrottle is set to be equal or more than 17 ms.
@@ -138,8 +137,7 @@ public object ReactScrollViewHelper {
               contentView.width,
               contentView.height,
               scrollView.width,
-              scrollView.height,
-              experimental_isSynchronous))
+              scrollView.height))
       scrollView.lastScrollDispatchTime = now
     }
   }
@@ -374,29 +372,13 @@ public object ReactScrollViewHelper {
   T : HasScrollEventThrottle?,
   T : HasScrollState?,
   T : HasStateWrapper?,
-  T : ViewGroup {
-    updateStateOnScrollChanged(scrollView, xVelocity, yVelocity, false)
-  }
-
-  @JvmStatic
-  public fun <T> updateStateOnScrollChanged(
-      scrollView: T,
-      xVelocity: Float,
-      yVelocity: Float,
-      experimental_synchronous: Boolean,
-  ) where
-  T : HasFlingAnimator?,
-  T : HasScrollEventThrottle?,
-  T : HasScrollState?,
-  T : HasStateWrapper?,
   T : ViewGroup {
     // Race an UpdateState with every onScroll. This makes it more likely that, in Fabric,
     // when JS processes the scroll event, the C++ ShadowNode representation will have a
     // "more correct" scroll position. It will frequently be /incorrect/ but this decreases
     // the error as much as possible.
     updateFabricScrollState(scrollView, scrollView.scrollX, scrollView.scrollY)
-    emitScrollEvent(
-        scrollView, ScrollEventType.SCROLL, xVelocity, yVelocity, experimental_synchronous)
+    emitScrollEvent(scrollView, xVelocity, yVelocity)
   }
 
   public fun <T> registerFlingAnimator(scrollView: T) where

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactScrollViewManager.java

@@ -167,11 +167,6 @@ public class ReactScrollViewManager extends ViewGroupManager<ReactScrollView>
     view.setScrollPerfTag(scrollPerfTag);
   }
 
-  @ReactProp(name = "enableSyncOnScroll")
-  public void setEnableSyncOnScroll(ReactScrollView view, boolean value) {
-    view.setEnableSyncOnScroll(value);
-  }
-
   @ReactProp(name = "pagingEnabled")
   public void setPagingEnabled(ReactScrollView view, boolean pagingEnabled) {
     view.setPagingEnabled(pagingEnabled);

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/scroll/ScrollEvent.kt

@@ -29,7 +29,6 @@ public class ScrollEvent private constructor() : Event<ScrollEvent>() {
   private var scrollViewHeight = 0
   private var scrollEventType: ScrollEventType? = null
   private var timestamp: Long = 0
-  private var experimental_isSynchronous = false
 
   override fun onDispose() {
     try {
@@ -53,7 +52,6 @@ public class ScrollEvent private constructor() : Event<ScrollEvent>() {
       contentHeight: Int,
       scrollViewWidth: Int,
       scrollViewHeight: Int,
-      experimental_isSynchronous: Boolean,
   ) {
     super.init(surfaceId, viewTag)
     this.scrollEventType = scrollEventType
@@ -66,7 +64,6 @@ public class ScrollEvent private constructor() : Event<ScrollEvent>() {
     this.scrollViewWidth = scrollViewWidth
     this.scrollViewHeight = scrollViewHeight
     this.timestamp = SystemClock.uptimeMillis()
-    this.experimental_isSynchronous = experimental_isSynchronous
   }
 
   override fun getEventName(): String =
@@ -74,10 +71,6 @@ public class ScrollEvent private constructor() : Event<ScrollEvent>() {
 
   override fun canCoalesce(): Boolean = scrollEventType == ScrollEventType.SCROLL
 
-  override fun experimental_isSynchronous(): Boolean {
-    return experimental_isSynchronous
-  }
-
   override fun getEventData(): WritableMap {
     val contentInset = Arguments.createMap()
     contentInset.putDouble("top", 0.0)
@@ -125,7 +118,6 @@ public class ScrollEvent private constructor() : Event<ScrollEvent>() {
         contentHeight: Int,
         scrollViewWidth: Int,
         scrollViewHeight: Int,
-        experimental_isSynchronous: Boolean,
     ): ScrollEvent =
         (EVENTS_POOL.acquire() ?: ScrollEvent()).apply {
           init(
@@ -139,8 +131,7 @@ public class ScrollEvent private constructor() : Event<ScrollEvent>() {
               contentWidth,
               contentHeight,
               scrollViewWidth,
-              scrollViewHeight,
-              experimental_isSynchronous)
+              scrollViewHeight)
         }
 
     @Deprecated(
@@ -172,7 +163,6 @@ public class ScrollEvent private constructor() : Event<ScrollEvent>() {
             contentHeight,
             scrollViewWidth,
             scrollViewHeight,
-            false,
         )
   }
 }

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactTextInputManager.java

@@ -1302,8 +1302,7 @@ public class ReactTextInputManager extends BaseViewManager<ReactEditText, Layout
                 0, // can't get content width
                 0, // can't get content height
                 mReactEditText.getWidth(),
-                mReactEditText.getHeight(),
-                false);
+                mReactEditText.getHeight());
 
         mEventDispatcher.dispatchEvent(event);
 

packages/react-native/ReactCommon/react/renderer/components/scrollview/ScrollViewEventEmitter.cpp

@@ -13,14 +13,6 @@ void ScrollViewEventEmitter::onScroll(const ScrollEvent& scrollEvent) const {
   dispatchUniqueEvent("scroll", std::make_shared<ScrollEvent>(scrollEvent));
 }
 
-void ScrollViewEventEmitter::experimental_onDiscreteScroll(
-    const ScrollEvent& scrollEvent) const {
-  dispatchEvent(
-      "scroll",
-      std::make_shared<ScrollEvent>(scrollEvent),
-      RawEvent::Category::Discrete);
-}
-
 void ScrollViewEventEmitter::onScrollToTop(
     const ScrollEvent& scrollEvent) const {
   dispatchUniqueEvent(

packages/react-native/ReactCommon/react/renderer/components/scrollview/ScrollViewEventEmitter.h

@@ -23,7 +23,6 @@ class ScrollViewEventEmitter : public ViewEventEmitter {
   using Metrics = ScrollEvent;
 
   void onScroll(const ScrollEvent& scrollEvent) const;
-  void experimental_onDiscreteScroll(const ScrollEvent& scrollEvent) const;
   void onScrollBeginDrag(const ScrollEvent& scrollEvent) const;
   void onScrollEndDrag(const ScrollEvent& scrollEvent) const;
   void onMomentumScrollBegin(const ScrollEvent& scrollEvent) const;

packages/react-native/ReactCommon/react/renderer/components/scrollview/ScrollViewProps.cpp

@@ -120,15 +120,6 @@ ScrollViewProps::ScrollViewProps(
                     "endDraggingSensitivityMultiplier",
                     sourceProps.endDraggingSensitivityMultiplier,
                     (Float)1)),
-      enableSyncOnScroll(
-          ReactNativeFeatureFlags::enableCppPropsIteratorSetter()
-              ? sourceProps.enableSyncOnScroll
-              : convertRawProp(
-                    context,
-                    rawProps,
-                    "enableSyncOnScroll",
-                    sourceProps.enableSyncOnScroll,
-                    false)),
       directionalLockEnabled(
           ReactNativeFeatureFlags::enableCppPropsIteratorSetter()
               ? sourceProps.directionalLockEnabled
@@ -411,7 +402,6 @@ void ScrollViewProps::setProp(
     RAW_SET_PROP_SWITCH_CASE_BASIC(maximumZoomScale);
     RAW_SET_PROP_SWITCH_CASE_BASIC(minimumZoomScale);
     RAW_SET_PROP_SWITCH_CASE_BASIC(scrollEnabled);
-    RAW_SET_PROP_SWITCH_CASE_BASIC(enableSyncOnScroll);
     RAW_SET_PROP_SWITCH_CASE_BASIC(endDraggingSensitivityMultiplier);
     RAW_SET_PROP_SWITCH_CASE_BASIC(pagingEnabled);
     RAW_SET_PROP_SWITCH_CASE_BASIC(pinchGestureEnabled);

packages/react-native/ReactCommon/react/renderer/components/scrollview/ScrollViewProps.h

@@ -43,7 +43,6 @@ class ScrollViewProps final : public ViewProps {
   bool automaticallyAdjustKeyboardInsets{false};
   Float decelerationRate{0.998f};
   Float endDraggingSensitivityMultiplier{1};
-  bool enableSyncOnScroll{false};
   bool directionalLockEnabled{};
   ScrollViewIndicatorStyle indicatorStyle{};
   ScrollViewKeyboardDismissMode keyboardDismissMode{};

packages/react-native/src/private/components/HScrollViewNativeComponents.js

@@ -12,43 +12,18 @@
 import type {ScrollViewNativeProps} from '../../../Libraries/Components/ScrollView/ScrollViewNativeComponentType';
 import type {ViewProps} from '../../../Libraries/Components/View/ViewPropTypes';
 import type {HostComponent} from '../../../Libraries/Renderer/shims/ReactNativeTypes';
-import type {TScrollViewNativeImperativeHandle} from './useSyncOnScroll';
 
 import AndroidHorizontalScrollViewNativeComponent from '../../../Libraries/Components/ScrollView/AndroidHorizontalScrollViewNativeComponent';
 import ScrollContentViewNativeComponent from '../../../Libraries/Components/ScrollView/ScrollContentViewNativeComponent';
 import ScrollViewNativeComponent from '../../../Libraries/Components/ScrollView/ScrollViewNativeComponent';
 import Platform from '../../../Libraries/Utilities/Platform';
 import AndroidHorizontalScrollContentViewNativeComponent from '../specs/components/AndroidHorizontalScrollContentViewNativeComponent';
-import useSyncOnScroll from './useSyncOnScroll';
-import * as React from 'react';
-import {forwardRef} from 'react';
 
-const HScrollViewNativeComponentForPlatform =
+export const HScrollViewNativeComponent: HostComponent<ScrollViewNativeProps> =
   Platform.OS === 'android'
     ? AndroidHorizontalScrollViewNativeComponent
     : ScrollViewNativeComponent;
 
-// TODO: After upgrading to React 19, remove `forwardRef` from this component.
-export const HScrollViewNativeComponent: component(
-  ref: React.RefSetter<TScrollViewNativeImperativeHandle>,
-  ...ScrollViewNativeProps
-) = forwardRef(function HScrollViewNativeComponent(
-  props: ScrollViewNativeProps,
-  ref: ?React.RefSetter<TScrollViewNativeImperativeHandle | null>,
-): React.Node {
-  const [componentRef, enableSyncOnScroll] = useSyncOnScroll(ref);
-  // NOTE: When `useSyncOnScroll` triggers an update, `props` will not have
-  // changed. Notably, `props.children` will be the same, allowing React to
-  // bail out during reconciliation.
-  return (
-    <HScrollViewNativeComponentForPlatform
-      {...props}
-      ref={componentRef}
-      enableSyncOnScroll={enableSyncOnScroll}
-    />
-  );
-});
-
 export const HScrollContentViewNativeComponent: HostComponent<ViewProps> =
   Platform.OS === 'android'
     ? AndroidHorizontalScrollContentViewNativeComponent

packages/react-native/src/private/components/VScrollViewNativeComponents.js

@@ -12,36 +12,14 @@
 import type {ScrollViewNativeProps} from '../../../Libraries/Components/ScrollView/ScrollViewNativeComponentType';
 import type {ViewProps} from '../../../Libraries/Components/View/ViewPropTypes';
 import type {HostComponent} from '../../../Libraries/Renderer/shims/ReactNativeTypes';
-import type {TScrollViewNativeImperativeHandle} from './useSyncOnScroll';
 
 import ScrollContentViewNativeComponent from '../../../Libraries/Components/ScrollView/ScrollContentViewNativeComponent';
 import ScrollViewNativeComponent from '../../../Libraries/Components/ScrollView/ScrollViewNativeComponent';
 import View from '../../../Libraries/Components/View/View';
 import Platform from '../../../Libraries/Utilities/Platform';
-import useSyncOnScroll from './useSyncOnScroll';
-import * as React from 'react';
-import {forwardRef} from 'react';
 
-// TODO: After upgrading to React 19, remove `forwardRef` from this component.
-export const VScrollViewNativeComponent: component(
-  ref: React.RefSetter<TScrollViewNativeImperativeHandle>,
-  ...props: ScrollViewNativeProps
-) = forwardRef(function VScrollViewNativeComponent(
-  props: ScrollViewNativeProps,
-  ref: ?React.RefSetter<TScrollViewNativeImperativeHandle | null>,
-): React.Node {
-  const [componentRef, enableSyncOnScroll] = useSyncOnScroll(ref);
-  // NOTE: When `useSyncOnScroll` triggers an update, `props` will not have
-  // changed. Notably, `props.children` will be the same, allowing React to
-  // bail out during reconciliation.
-  return (
-    <ScrollViewNativeComponent
-      {...props}
-      ref={componentRef}
-      enableSyncOnScroll={enableSyncOnScroll}
-    />
-  );
-});
+export const VScrollViewNativeComponent: HostComponent<ScrollViewNativeProps> =
+  ScrollViewNativeComponent;
 
 export const VScrollContentViewNativeComponent: HostComponent<ViewProps> =
   Platform.OS === 'android' ? View : ScrollContentViewNativeComponent;

packages/react-native/src/private/components/useSyncOnScroll.js

@@ -1,48 +0,0 @@
-/**
- * Copyright (c) Meta Platforms, Inc. and affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- *
- * @flow strict-local
- * @format
- * @oncall react_native
- */
-
-import type {ScrollViewNativeProps} from '../../../Libraries/Components/ScrollView/ScrollViewNativeComponentType';
-import type {HostComponent} from '../../../Libraries/Renderer/shims/ReactNativeTypes';
-
-import * as React from 'react';
-import {useImperativeHandle, useRef, useState} from 'react';
-
-export type TScrollViewNativeComponentInstance = React.ElementRef<
-  HostComponent<ScrollViewNativeProps>,
->;
-
-export type TScrollViewNativeImperativeHandle = {
-  componentRef: React.RefObject<TScrollViewNativeComponentInstance | null>,
-  unstable_setEnableSyncOnScroll: (enabled: true) => void,
-};
-
-/**
- * Hook used by `HScrollViewNativeComponent` and `VScrollViewNativeComponent`
- * to make an implementation of `unstable_setEnableSyncOnScroll` available that
- * does not require updating all `ScrollView` children.
- */
-export default function useSyncOnScroll(
-  inputRef: ?React.RefSetter<TScrollViewNativeImperativeHandle | null>,
-): [React.RefSetter<TScrollViewNativeComponentInstance | null>, true | void] {
-  const componentRef = useRef<TScrollViewNativeComponentInstance | null>(null);
-  const [enableSyncOnScroll, setEnableSyncOnScroll] = useState<true | void>();
-
-  useImperativeHandle<TScrollViewNativeImperativeHandle>(inputRef, () => {
-    return {
-      componentRef,
-      unstable_setEnableSyncOnScroll(enabled: true): void {
-        setEnableSyncOnScroll(enabled);
-      },
-    };
-  }, []);
-
-  return [componentRef, enableSyncOnScroll];
-}