From 3ae668f382fade6325457b07efd0a39b8d8e966b Mon Sep 17 00:00:00 2001
From: Jack Pope <jackpope1@gmail.com>
Date: Fri, 28 Feb 2025 20:50:13 -0500
Subject: [PATCH] Fix event listener untracking

---
 .../src/client/ReactFiberConfigDOM.js         |  7 +-
 .../__tests__/ReactDOMFragmentRefs-test.js    | 81 +++++++++++++++++++
 2 files changed, 84 insertions(+), 4 deletions(-)

diff --git a/packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js b/packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js
index 5bd624000b6d9..c19354f1e767a 100644
--- a/packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js
+++ b/packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js
@@ -1619,8 +1619,7 @@ FragmentInstancePseudoElement.prototype.removeEventListener = function (
   listener: EventListener,
   optionsOrUseCapture?: EventListenerOptionsOrUseCapture,
 ): void {
-  const listeners = this._eventListeners;
-  if (listeners === undefined || listeners.length === 0) {
+  if (this._eventListeners === undefined || this._eventListeners.length === 0) {
     return;
   }
   traverseFragmentInstanceChildren(
@@ -1633,12 +1632,12 @@ FragmentInstancePseudoElement.prototype.removeEventListener = function (
       optionsOrUseCapture,
     ),
   );
-  const index = indexOfEventListener(listeners, {
+  const index = indexOfEventListener(this._eventListeners, {
     type,
     listener,
     optionsOrUseCapture,
   });
-  this._eventListeners = listeners.splice(index, 1);
+  this._eventListeners.splice(index, 1);
 };
 function removeEventListenerFromChild(
   type: string,
diff --git a/packages/react-dom/src/__tests__/ReactDOMFragmentRefs-test.js b/packages/react-dom/src/__tests__/ReactDOMFragmentRefs-test.js
index 9f7ec809c96e1..4ae00f7b01215 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFragmentRefs-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFragmentRefs-test.js
@@ -412,6 +412,87 @@ describe('FragmentRefs', () => {
       expect(logs).toEqual(['Host A', 'Host B']);
     });
 
+    // @gate enableFragmentRefs
+    it('allows adding and cleaning up listeners in effects', async () => {
+      const root = ReactDOMClient.createRoot(container);
+
+      let logs = [];
+      function logClick(e) {
+        logs.push(e.currentTarget.id);
+      }
+
+      let rerender;
+      let removeEventListeners;
+
+      function Test() {
+        const fragmentRef = React.useRef(null);
+        const [_, setState] = React.useState(0);
+        rerender = () => {
+          setState(p => p + 1);
+        };
+        removeEventListeners = () => {
+          fragmentRef.current.removeEventListener('click', logClick);
+        };
+        React.useEffect(() => {
+          fragmentRef.current.addEventListener('click', logClick);
+
+          return removeEventListeners;
+        });
+
+        return (
+          <Fragment ref={fragmentRef}>
+            <div id="child-a" />
+          </Fragment>
+        );
+      }
+
+      // The event listener was applied
+      await act(() => root.render(<Test />));
+      expect(logs).toEqual([]);
+      document.querySelector('#child-a').click();
+      expect(logs).toEqual(['child-a']);
+
+      // The event listener can be removed and re-added
+      logs = [];
+      await act(rerender);
+      document.querySelector('#child-a').click();
+      expect(logs).toEqual(['child-a']);
+
+      // The event listener
+      // Split into two tests
+      // 1. Removed event listeners are not added to new children
+      // 2. It can remove and reapply event listeners in effects
+    });
+
+    it('does not apply removed event listeners to new children', async () => {
+      const root = ReactDOMClient.createRoot(container);
+      const fragmentRef = React.createRef(null);
+      function Test() {
+        return (
+          <Fragment ref={fragmentRef}>
+            <div id="child-a" />
+          </Fragment>
+        );
+      }
+
+      let logs = [];
+      function logClick(e) {
+        logs.push(e.currentTarget.id);
+      }
+      await act(() => {
+        root.render(<Test />);
+      });
+      fragmentRef.current.addEventListener('click', logClick);
+      const childA = document.querySelector('#child-a');
+      childA.click();
+      expect(logs).toEqual(['child-a']);
+
+      logs = [];
+      fragmentRef.current.removeEventListener('click', logClick);
+      childA.click();
+      expect(logs).toEqual([]);
+    });
+
     describe('with activity', () => {
       // @gate enableFragmentRefs && enableActivity
       it('does not apply event listeners to hidden trees', async () => {