[cherry-pick][4.1] Fix commits during the Android draw pass

apps/common-app/src/apps/reanimated/examples/AndroidDrawPassExample.tsx

@@ -0,0 +1,181 @@
+import { useNavigation } from '@react-navigation/native';
+import type { NativeStackNavigationProp } from '@react-navigation/native-stack';
+import { createNativeStackNavigator } from '@react-navigation/native-stack';
+import React, { useCallback } from 'react';
+import { Button, StyleSheet, Text, View } from 'react-native';
+import Animated, {
+  interpolate,
+  useAnimatedScrollHandler,
+  useAnimatedStyle,
+  useSharedValue,
+} from 'react-native-reanimated';
+
+type AndroidDrawPassParamList = {
+  Description: undefined;
+  ScrollList: undefined;
+};
+
+const Stack = createNativeStackNavigator<AndroidDrawPassParamList>();
+const LIST_ITEM_COUNT = 80;
+
+export default function AndroidDrawPassExample() {
+  return (
+    <View style={descriptionStyles.container}>
+      <Stack.Navigator>
+        <Stack.Screen name="Description" component={DescriptionScreen} />
+        <Stack.Screen name="ScrollList" component={ScrollListScreen} />
+      </Stack.Navigator>
+    </View>
+  );
+}
+
+function DescriptionScreen() {
+  const navigation =
+    useNavigation<NativeStackNavigationProp<AndroidDrawPassParamList>>();
+
+  return (
+    <View style={descriptionStyles.centered}>
+      <Text style={descriptionStyles.title}>Android Draw Pass Fix</Text>
+      <Text style={descriptionStyles.description}>
+        This example reproduces a bug that was fixed on Android where committing
+        updates during a draw pass caused a crash.
+      </Text>
+      <Text style={descriptionStyles.description}>
+        Previously, if you navigated to the scroll list and went back{' '}
+        <Text style={descriptionStyles.bold}>while actively scrolling</Text>,
+        the app would crash. This happened because Reanimated was attempting to
+        commit UI updates while Android was in the middle of a draw pass, and
+        sometimes React would have some hierarchy mutations queued up that would
+        get bundled with these updates, triggering the crash.
+      </Text>
+      <Text style={descriptionStyles.description}>
+        The fix detects when a draw pass is in progress and pushes only
+        non-layout updates through the synchronous update path, while layout
+        updates are deferred to the next frame. This ensures that we never
+        attempt to mutate the view hierarchy during a draw pass.
+      </Text>
+      <Button
+        title="Go to scroll list"
+        onPress={() => navigation.navigate('ScrollList')}
+      />
+    </View>
+  );
+}
+
+function ListItem({ index }: { index: number }) {
+  return (
+    <View style={listStyles.listItem}>
+      <Text>Item {index + 1}</Text>
+      <Text style={listStyles.listItemSubtext}>
+        Scroll fast and press Back — this used to crash on Android
+      </Text>
+    </View>
+  );
+}
+
+function ScrollListScreen() {
+  const scrollY = useSharedValue(0);
+
+  const scrollHandler = useAnimatedScrollHandler({
+    onScroll: (event) => {
+      scrollY.value = event.contentOffset.y;
+    },
+  });
+
+  const floatingBadgeStyle = useAnimatedStyle(() => {
+    const scale = interpolate(scrollY.value, [0, 100, 200], [1, 1.2, 0.9]);
+    const rotate = interpolate(scrollY.value, [0, 150, 300], [0, 5, -5]);
+
+    return {
+      width: 100,
+      transform: [{ scale }, { rotate: `${rotate}deg` }],
+    };
+  });
+
+  const renderItem = useCallback(
+    ({ item }: { item: number }) => <ListItem index={item} />,
+    []
+  );
+
+  const keyExtractor = useCallback((item: number) => `item-${item}`, []);
+  const data = Array.from({ length: LIST_ITEM_COUNT }, (_, index) => index);
+
+  return (
+    <View style={listStyles.container}>
+      <Animated.View style={[listStyles.floatingBadge, floatingBadgeStyle]}>
+        <Text style={listStyles.badgeText}>scrollY</Text>
+      </Animated.View>
+
+      <Animated.FlatList
+        data={data}
+        renderItem={renderItem}
+        keyExtractor={keyExtractor}
+        onScroll={scrollHandler}
+        scrollEventThrottle={16}
+        contentContainerStyle={listStyles.listContent}
+        showsVerticalScrollIndicator
+      />
+    </View>
+  );
+}
+
+const descriptionStyles = StyleSheet.create({
+  container: {
+    flex: 1,
+  },
+  centered: {
+    flex: 1,
+    alignItems: 'center',
+    gap: 16,
+    padding: 24,
+  },
+  title: {
+    fontSize: 20,
+    fontWeight: '700',
+    marginBottom: 4,
+  },
+  description: {
+    color: '#333',
+    fontSize: 15,
+    lineHeight: 22,
+  },
+  bold: {
+    fontWeight: '700',
+  },
+});
+
+const listStyles = StyleSheet.create({
+  container: {
+    flex: 1,
+  },
+  floatingBadge: {
+    position: 'absolute',
+    top: 100,
+    right: 20,
+    zIndex: 10,
+    paddingVertical: 8,
+    paddingHorizontal: 14,
+    borderRadius: 12,
+    backgroundColor: 'rgba(255, 149, 0, 0.9)',
+  },
+  badgeText: {
+    color: '#fff',
+    fontWeight: '600',
+  },
+  listContent: {
+    paddingTop: 24,
+    paddingBottom: 40,
+    paddingHorizontal: 20,
+  },
+  listItem: {
+    marginBottom: 8,
+    borderRadius: 8,
+    paddingVertical: 16,
+    paddingHorizontal: 12,
+    backgroundColor: 'rgba(128, 128, 128, 0.12)',
+  },
+  listItemSubtext: {
+    marginTop: 6,
+    opacity: 0.8,
+  },
+});

apps/common-app/src/apps/reanimated/examples/StickyHeaderExample.tsx

@@ -24,7 +24,10 @@ export default function StickyHeaderExample() {
   });
 
   const animatedStyle = useAnimatedStyle(() => {
-    return { transform: [{ translateY: offset.value }] };
+    return {
+      transform: [{ translateY: offset.value }],
+      width: (offset.value % 200) + 100,
+    };
   });
 
   return (

apps/common-app/src/apps/reanimated/examples/index.ts

@@ -134,6 +134,7 @@ import WorkletExample from './WorkletExample';
 import WorkletFactoryCrash from './WorkletFactoryCrashExample';
 import WorkletRuntimeExample from './WorkletRuntimeExample';
 import InstanceDiscoveryExample from './InstanceDiscoveryExample';
+import AndroidDrawPassExample from './AndroidDrawPassExample';
 
 interface Example {
   icon?: string;
@@ -154,6 +155,11 @@ export const EXAMPLES: Record<string, Example> = {
     title: 'FPS',
     screen: FpsExample,
   },
+  AndroidDrawPassExample: {
+    icon: '✍️',
+    title: 'Android Draw Pass',
+    screen: AndroidDrawPassExample,
+  },
   ThirdPartyComponentsExample: {
     icon: '3️⃣',
     title: 'Third party components',

packages/react-native-reanimated/Common/cpp/reanimated/Fabric/updates/UpdatesRegistry.cpp

@@ -32,6 +32,18 @@ void UpdatesRegistry::flushUpdates(UpdatesBatch &updatesBatch) {
   }
 }
 
+UpdatesBatch UpdatesRegistry::getPendingUpdates() {
+  auto lock = std::lock_guard<std::mutex>{mutex_};
+  flushUpdatesToRegistry(updatesBatch_);
+
+  UpdatesBatch updatesBatch;
+  for (const auto &[tag, pair] : updatesRegistry_) {
+    const auto &[shadowNode, props] = pair;
+    updatesBatch.emplace_back(shadowNode, props);
+  }
+  return updatesBatch;
+}
+
 void UpdatesRegistry::collectProps(PropsMap &propsMap) {
   std::lock_guard<std::mutex> lock{mutex_};
 

packages/react-native-reanimated/Common/cpp/reanimated/Fabric/updates/UpdatesRegistry.h

@@ -49,6 +49,7 @@ class UpdatesRegistry {
 
   void flushUpdates(UpdatesBatch &updatesBatch);
   void collectProps(PropsMap &propsMap);
+  UpdatesBatch getPendingUpdates();
 
  protected:
   mutable std::mutex mutex_;