[EventSystem] Revise onBeforeBlur propagation mechanics (facebook#20020)

packages/react-art/src/ReactARTHostConfig.js

@@ -467,7 +467,7 @@ export function makeClientIdInDEV(warnOnAccessInDEV: () => void): OpaqueIDType {
   throw new Error('Not yet implemented');
 }
 
-export function beforeActiveInstanceBlur() {
+export function beforeActiveInstanceBlur(internalInstanceHandle: Object) {
   // noop
 }
 

packages/react-dom/src/client/ReactDOMHostConfig.js

@@ -232,10 +232,13 @@ export function prepareForCommit(containerInfo: Container): Object | null {
   return activeInstance;
 }
 
-export function beforeActiveInstanceBlur(): void {
+export function beforeActiveInstanceBlur(internalInstanceHandle: Object): void {
   if (enableCreateEventHandleAPI) {
     ReactBrowserEventEmitterSetEnabled(true);
-    dispatchBeforeDetachedBlur((selectionInformation: any).focusedElem);
+    dispatchBeforeDetachedBlur(
+      (selectionInformation: any).focusedElem,
+      internalInstanceHandle,
+    );
     ReactBrowserEventEmitterSetEnabled(false);
   }
 }
@@ -499,12 +502,17 @@ function createEvent(type: DOMEventName, bubbles: boolean): Event {
   return event;
 }
 
-function dispatchBeforeDetachedBlur(target: HTMLElement): void {
+function dispatchBeforeDetachedBlur(
+  target: HTMLElement,
+  internalInstanceHandle: Object,
+): void {
   if (enableCreateEventHandleAPI) {
     const event = createEvent('beforeblur', true);
     // Dispatch "beforeblur" directly on the target,
     // so it gets picked up by the event system and
     // can propagate through the React internal tree.
+    // $FlowFixMe: internal field
+    event._detachedInterceptFiber = internalInstanceHandle;
     target.dispatchEvent(event);
   }
 }

packages/react-dom/src/events/DOMPluginEventSystem.js

@@ -658,10 +658,11 @@ export function accumulateSinglePhaseListeners(
   nativeEventType: string,
   inCapturePhase: boolean,
   accumulateTargetOnly: boolean,
+  nativeEvent: AnyNativeEvent,
 ): Array<DispatchListener> {
   const captureName = reactName !== null ? reactName + 'Capture' : null;
   const reactEventName = inCapturePhase ? captureName : reactName;
-  const listeners: Array<DispatchListener> = [];
+  let listeners: Array<DispatchListener> = [];
 
   let instance = targetFiber;
   let lastHostComponent = null;
@@ -740,6 +741,23 @@ export function accumulateSinglePhaseListeners(
     if (accumulateTargetOnly) {
       break;
     }
+    // If we are processing the onBeforeBlur event, then we need to take
+    // into consideration that part of the React tree might have been hidden
+    // or deleted (as we're invoking this event during commit). We can find
+    // this out by checking if intercept fiber set on the event matches the
+    // current instance fiber. In which case, we should clear all existing
+    // listeners.
+    if (enableCreateEventHandleAPI && nativeEvent.type === 'beforeblur') {
+      // $FlowFixMe: internal field
+      const detachedInterceptFiber = nativeEvent._detachedInterceptFiber;
+      if (
+        detachedInterceptFiber !== null &&
+        (detachedInterceptFiber === instance ||
+          detachedInterceptFiber === instance.alternate)
+      ) {
+        listeners = [];
+      }
+    }
     instance = instance.return;
   }
   return listeners;

packages/react-dom/src/events/__tests__/DOMPluginEventSystem-test.internal.js

@@ -2424,6 +2424,60 @@ describe('DOMPluginEventSystem', () => {
             expect(log).toEqual(['beforeblur', 'afterblur']);
           });
 
+          // @gate experimental
+          it('beforeblur should skip handlers from a deleted subtree after the focused element is unmounted', () => {
+            const onBeforeBlur = jest.fn();
+            const innerRef = React.createRef();
+            const innerRef2 = React.createRef();
+            const setBeforeBlurHandle = ReactDOM.unstable_createEventHandle(
+              'beforeblur',
+            );
+            const ref2 = React.createRef();
+
+            const Component = ({show}) => {
+              const ref = React.useRef(null);
+
+              React.useEffect(() => {
+                const clear1 = setBeforeBlurHandle(ref.current, onBeforeBlur);
+                let clear2;
+                if (ref2.current) {
+                  clear2 = setBeforeBlurHandle(ref2.current, onBeforeBlur);
+                }
+
+                return () => {
+                  clear1();
+                  if (clear2) {
+                    clear2();
+                  }
+                };
+              });
+
+              return (
+                <div ref={ref}>
+                  {show && (
+                    <div ref={ref2}>
+                      <input ref={innerRef} />
+                    </div>
+                  )}
+                  <div ref={innerRef2} />
+                </div>
+              );
+            };
+
+            ReactDOM.render(<Component show={true} />, container);
+            Scheduler.unstable_flushAll();
+
+            const inner = innerRef.current;
+            const target = createEventTarget(inner);
+            target.focus();
+            expect(onBeforeBlur).toHaveBeenCalledTimes(0);
+
+            ReactDOM.render(<Component show={false} />, container);
+            Scheduler.unstable_flushAll();
+
+            expect(onBeforeBlur).toHaveBeenCalledTimes(1);
+          });
+
           // @gate experimental
           it('beforeblur and afterblur are called after a focused element is suspended', () => {
             const log = [];
@@ -2510,6 +2564,87 @@ describe('DOMPluginEventSystem', () => {
             document.body.removeChild(container2);
           });
 
+          // @gate experimental
+          it('beforeblur should skip handlers from a deleted subtree after the focused element is suspended', () => {
+            const onBeforeBlur = jest.fn();
+            const innerRef = React.createRef();
+            const innerRef2 = React.createRef();
+            const setBeforeBlurHandle = ReactDOM.unstable_createEventHandle(
+              'beforeblur',
+            );
+            const ref2 = React.createRef();
+            const Suspense = React.Suspense;
+            let suspend = false;
+            let resolve;
+            const promise = new Promise(
+              resolvePromise => (resolve = resolvePromise),
+            );
+
+            function Child() {
+              if (suspend) {
+                throw promise;
+              } else {
+                return <input ref={innerRef} />;
+              }
+            }
+
+            const Component = () => {
+              const ref = React.useRef(null);
+
+              React.useEffect(() => {
+                const clear1 = setBeforeBlurHandle(ref.current, onBeforeBlur);
+                let clear2;
+                if (ref2.current) {
+                  clear2 = setBeforeBlurHandle(ref2.current, onBeforeBlur);
+                }
+
+                return () => {
+                  clear1();
+                  if (clear2) {
+                    clear2();
+                  }
+                };
+              });
+
+              return (
+                <div ref={ref}>
+                  <Suspense fallback="Loading...">
+                    <div ref={ref2}>
+                      <Child />
+                    </div>
+                  </Suspense>
+                  <div ref={innerRef2} />
+                </div>
+              );
+            };
+
+            const container2 = document.createElement('div');
+            document.body.appendChild(container2);
+
+            const root = ReactDOM.createRoot(container2);
+
+            act(() => {
+              root.render(<Component />);
+            });
+            jest.runAllTimers();
+
+            const inner = innerRef.current;
+            const target = createEventTarget(inner);
+            target.focus();
+            expect(onBeforeBlur).toHaveBeenCalledTimes(0);
+
+            suspend = true;
+            act(() => {
+              root.render(<Component />);
+            });
+            jest.runAllTimers();
+
+            expect(onBeforeBlur).toHaveBeenCalledTimes(1);
+            resolve();
+
+            document.body.removeChild(container2);
+          });
+
           // @gate experimental
           it('regression: does not fire beforeblur/afterblur if target is already hidden', () => {
             const Suspense = React.Suspense;

packages/react-dom/src/events/plugins/SimpleEventPlugin.js

@@ -200,6 +200,7 @@ function extractEvents(
       nativeEvent.type,
       inCapturePhase,
       accumulateTargetOnly,
+      nativeEvent,
     );
     if (listeners.length > 0) {
       // Intentionally create event lazily.

packages/react-native-renderer/src/ReactFabricHostConfig.js

@@ -481,7 +481,7 @@ export function makeClientIdInDEV(warnOnAccessInDEV: () => void): OpaqueIDType {
   throw new Error('Not yet implemented');
 }
 
-export function beforeActiveInstanceBlur() {
+export function beforeActiveInstanceBlur(internalInstanceHandle: Object) {
   // noop
 }
 

packages/react-native-renderer/src/ReactNativeHostConfig.js

@@ -534,7 +534,7 @@ export function makeClientIdInDEV(warnOnAccessInDEV: () => void): OpaqueIDType {
   throw new Error('Not yet implemented');
 }
 
-export function beforeActiveInstanceBlur() {
+export function beforeActiveInstanceBlur(internalInstanceHandle: Object) {
   // noop
 }
 

packages/react-reconciler/src/ReactFiberWorkLoop.new.js

@@ -2172,7 +2172,7 @@ function commitBeforeMutationEffectsImpl(fiber: Fiber) {
       doesFiberContain(fiber, focusedInstanceHandle)
     ) {
       shouldFireAfterActiveInstanceBlur = true;
-      beforeActiveInstanceBlur();
+      beforeActiveInstanceBlur(fiber);
     }
   }
 
@@ -2206,7 +2206,7 @@ function commitBeforeMutationEffectsDeletions(deletions: Array<Fiber>) {
 
     if (doesFiberContain(fiber, ((focusedInstanceHandle: any): Fiber))) {
       shouldFireAfterActiveInstanceBlur = true;
-      beforeActiveInstanceBlur();
+      beforeActiveInstanceBlur(fiber);
     }
   }
 }

packages/react-reconciler/src/ReactFiberWorkLoop.old.js

@@ -2261,7 +2261,7 @@ function commitBeforeMutationEffects() {
       if ((nextEffect.flags & Deletion) !== NoFlags) {
         if (doesFiberContain(nextEffect, focusedInstanceHandle)) {
           shouldFireAfterActiveInstanceBlur = true;
-          beforeActiveInstanceBlur();
+          beforeActiveInstanceBlur(nextEffect);
         }
       } else {
         // TODO: Move this out of the hot path using a dedicated effect tag.
@@ -2271,7 +2271,7 @@ function commitBeforeMutationEffects() {
           doesFiberContain(nextEffect, focusedInstanceHandle)
         ) {
           shouldFireAfterActiveInstanceBlur = true;
-          beforeActiveInstanceBlur();
+          beforeActiveInstanceBlur(nextEffect);
         }
       }
     }

packages/react-test-renderer/src/ReactTestHostConfig.js

@@ -377,7 +377,7 @@ export function makeOpaqueHydratingObject(
   };
 }
 
-export function beforeActiveInstanceBlur() {
+export function beforeActiveInstanceBlur(internalInstanceHandle: Object) {
   // noop
 }