Continue MutationObserver batches after stale records

packages/react-native/src/private/webapis/mutationobserver/__tests__/MutationObserver-itest.js

@@ -23,6 +23,7 @@ import {createRef} from 'react';
 import {View} from 'react-native';
 import setUpMutationObserver from 'react-native/src/private/setup/setUpMutationObserver';
 import ReactNativeElement from 'react-native/src/private/webapis/dom/nodes/ReactNativeElement';
+import * as MutationObserverManager from 'react-native/src/private/webapis/mutationobserver/internals/MutationObserverManager';
 
 declare const MutationObserver: Class<MutationObserverType>;
 declare const MutationRecord: Class<MutationRecordType>;
@@ -658,6 +659,46 @@ describe('MutationObserver', () => {
         expect([...observer2Records2[0].addedNodes]).toEqual([]);
         expect([...observer2Records2[0].removedNodes]).toEqual([childNode111]);
       });
+
+      it('should dispatch other observers after ignoring disconnected records', () => {
+        const nodeRef = createRef<HostInstance>();
+        const root = Fantom.createRoot();
+
+        Fantom.runTask(() => {
+          root.render(<View ref={nodeRef} />);
+        });
+
+        const node = ensureReactNativeElement(nodeRef.current);
+        const activeCallback = jest.fn();
+        const activeObserver = new MutationObserver(activeCallback);
+        activeObserver.observe(node, {childList: true});
+        const disconnectedCallback = jest.fn();
+        const disconnectedObserver = new MutationObserver(disconnectedCallback);
+        disconnectedObserver.observe(node, {childList: true});
+
+        Fantom.runTask(() => {
+          root.render(
+            <View>
+              <View />
+            </View>,
+          );
+
+          Fantom.scheduleTask(() => {
+            const disconnectedObserverId =
+              disconnectedObserver.__getObserverID();
+            if (disconnectedObserverId == null) {
+              throw new Error(
+                'Expected the disconnected observer to be registered',
+              );
+            }
+            MutationObserverManager.unregisterObserver(disconnectedObserverId);
+          });
+        });
+
+        expect(disconnectedCallback).not.toHaveBeenCalled();
+        expect(activeCallback).toHaveBeenCalledTimes(1);
+        activeObserver.disconnect();
+      });
     });
 
     describe('multiple observed nodes in the same observer', () => {

packages/react-native/src/private/webapis/mutationobserver/internals/MutationObserverManager.js

@@ -181,7 +181,7 @@ function doNotifyMutationObservers(): void {
     if (!registeredObserver) {
       // This could happen if the observer is disconnected between commit
       // and mount. In this case, we can just ignore the entries.
-      return;
+      continue;
     }
 
     const {observer, callback} = registeredObserver;