Batch Android animated prop updates into one JNI call per surface

packages/react-native/Libraries/Animated/__tests__/AnimatedBackend-itest.js

@@ -77,6 +77,72 @@ test('animate marginLeft layout prop', () => {
   );
 });
 
+// A layout animation on one view must not push the other views of the
+// surface through a shadow tree commit: their non-layout props keep taking
+// the direct path to the mounted views.
+test('non-layout props stay on the direct path while another view animates layout', () => {
+  const movingRef = createRef<HostInstance>();
+
+  let _translateX;
+  let _translateXAnimation;
+  let _siblingHeight;
+  let _siblingHeightAnimation;
+
+  function MyApp() {
+    const translateX = useAnimatedValue(0);
+    const siblingHeight = useAnimatedValue(10);
+    _translateX = translateX;
+    _siblingHeight = siblingHeight;
+    return (
+      <View collapsable={false}>
+        <Animated.View
+          ref={movingRef}
+          style={{width: 100, height: 100, transform: [{translateX}]}}
+        />
+        <Animated.View style={{width: 100, height: siblingHeight}} />
+      </View>
+    );
+  }
+
+  const root = Fantom.createRoot();
+
+  Fantom.runTask(() => {
+    root.render(<MyApp />);
+  });
+
+  Fantom.runTask(() => {
+    _translateXAnimation = Animated.timing(_translateX, {
+      toValue: 100,
+      duration: 200,
+      useNativeDriver: true,
+    }).start();
+    _siblingHeightAnimation = Animated.timing(_siblingHeight, {
+      toValue: 110,
+      duration: 200,
+      useNativeDriver: true,
+    }).start();
+  });
+
+  Fantom.unstable_produceFramesForDuration(100);
+
+  // The sibling's height went through a commit; the transform did not.
+  expect(root.getRenderedOutput({props: ['height']}).toJSX()).toEqual(
+    <rn-view>
+      <rn-view key={0} height="100" />
+      <rn-view key={1} height="60" />
+    </rn-view>,
+  );
+  expect(
+    Fantom.unstable_getDirectManipulationProps(nullthrows(movingRef.current))
+      .transform,
+  ).toEqual([{translateX: 50}]);
+
+  Fantom.runTask(() => {
+    _translateXAnimation?.stop();
+    _siblingHeightAnimation?.stop();
+  });
+});
+
 test('animated opacity', () => {
   let _opacity;
   let _opacityAnimation;

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/fabric/FabricUIManager.java

@@ -62,6 +62,7 @@
 import com.facebook.react.fabric.mounting.MountingManager;
 import com.facebook.react.fabric.mounting.SurfaceMountingManager;
 import com.facebook.react.fabric.mounting.mountitems.BatchMountItem;
+import com.facebook.react.fabric.mounting.mountitems.BatchedAnimatedPropsMountItem;
 import com.facebook.react.fabric.mounting.mountitems.DispatchCommandMountItem;
 import com.facebook.react.fabric.mounting.mountitems.MountItem;
 import com.facebook.react.fabric.mounting.mountitems.MountItemFactory;
@@ -837,6 +838,27 @@ public void synchronouslyUpdateViewOnUIThread(final int reactTag, final Readable
         ReactMarkerConstants.FABRIC_UPDATE_UI_MAIN_THREAD_END, null, commitNumber);
   }
 
+  /** Called from C++ via JNI with a batch encoded by AnimatedPropBufferEncoder.cpp. */
+  @SuppressLint("NotInvokedPrivateMethod")
+  @SuppressWarnings("unused")
+  @UiThread
+  @ThreadConfined(UI)
+  private void synchronouslyUpdateViewBatch(
+      int[] intBuffer, double[] doubleBuffer, Object[] rawPropsBuffer) {
+    UiThreadUtil.assertOnUiThread();
+
+    int commitNumber = mCurrentSynchronousCommitNumber++;
+    ReactMarker.logFabricMarker(
+        ReactMarkerConstants.FABRIC_UPDATE_UI_MAIN_THREAD_START, null, commitNumber);
+
+    new BatchedAnimatedPropsMountItem(
+            intBuffer, doubleBuffer, rawPropsBuffer, mMountItemDispatcher)
+        .execute(mMountingManager);
+
+    ReactMarker.logFabricMarker(
+        ReactMarkerConstants.FABRIC_UPDATE_UI_MAIN_THREAD_END, null, commitNumber);
+  }
+
   /** Called from C++ via JNI. */
   @SuppressLint("NotInvokedPrivateMethod")
   @SuppressWarnings("unused")

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/fabric/mounting/MountingManager.kt

@@ -268,6 +268,16 @@ internal class MountingManager(
     getSurfaceManagerForView(reactTag)?.storeSynchronousMountPropsOverride(reactTag, props)
   }
 
+  /** Returns false when no surface owns [reactTag] yet, so the caller can queue the update. */
+  @UiThread
+  fun updateAnimatedPropsSynchronously(reactTag: Int, props: ReadableMap): Boolean {
+    assertOnUiThread()
+    val surfaceMountingManager = getSurfaceManagerForView(reactTag) ?: return false
+    surfaceMountingManager.storeSynchronousMountPropsOverride(reactTag, props)
+    surfaceMountingManager.updatePropsSynchronously(reactTag, props)
+    return true
+  }
+
   @UiThread
   fun updatePropsSynchronously(reactTag: Int, props: ReadableMap?) {
     assertOnUiThread()