Event API: responder event types should not re-register on EventComponent update (facebook#15514)

Author: trueadm

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

@@ -894,20 +894,14 @@ export function didNotFindHydratableSuspenseInstance(
 
 export function mountEventComponent(
   eventComponentInstance: ReactEventComponentInstance,
-): void {
-  if (enableEventAPI) {
-    updateEventComponent(eventComponentInstance);
-    mountEventResponder(eventComponentInstance);
-  }
-}
-
-export function updateEventComponent(
-  eventComponentInstance: ReactEventComponentInstance,
 ): void {
   if (enableEventAPI) {
     const rootContainerInstance = ((eventComponentInstance.rootInstance: any): Container);
     const rootElement = rootContainerInstance.ownerDocument;
     const responder = eventComponentInstance.responder;
+    if (__DEV__) {
+      Object.freeze(responder);
+    }
     const {rootEventTypes, targetEventTypes} = responder;
     if (targetEventTypes !== undefined) {
       listenToEventResponderEventTypes(targetEventTypes, rootElement);
@@ -919,9 +913,16 @@ export function updateEventComponent(
       );
       listenToEventResponderEventTypes(rootEventTypes, rootElement);
     }
+    mountEventResponder(eventComponentInstance);
   }
 }
 
+export function updateEventComponent(
+  eventComponentInstance: ReactEventComponentInstance,
+): void {
+  // NO-OP, why might use this in the future
+}
+
 export function unmountEventComponent(
   eventComponentInstance: ReactEventComponentInstance,
 ): void {

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

@@ -886,5 +886,7 @@ describe('DOMEventResponderSystem', () => {
         passiveSupported: true,
       },
     ]);
+
+    ReactDOM.render(<Test />, container);
   });
 });