Repository: facebook/react
Pull request: [DevTools][BugFix] Memoized Updaters Should Not Contain Deleted Nodes

There was a bug that occurred when a destroy effect is called that causes an update. The update would be added to the updaters list even though the fiber that was calling the destroy effect was unmounted and no longer exists. This PR:
* Adds a patch to Devtools to filter out all in the update list that aren't in the `fiberToIDMap` (which contains all fibers currently on screen)

Changed files:
filename: packages/react-devtools-shared/src/__tests__/profilingCache-test.js
patch: @@ -752,4 +752,97 @@ describe('ProfilingCache', () => {
     utils.act(() => store.profilerStore.stopProfiling());
     expect(container.textContent).toBe('About');
   });
+
+  it('components that were deleted and added to updaters during the layout phase should not crash', () => {
+    let setChildUnmounted;
+    function Child() {
+      const [, setState] = React.useState(false);
+
+      React.useLayoutEffect(() => {
+        return () => setState(true);
+      });
+
+      return null;
+    }
+
+    function App() {
+      const [childUnmounted, _setChildUnmounted] = React.useState(false);
+      setChildUnmounted = _setChildUnmounted;
+      return <>{!childUnmounted && <Child />}</>;
+    }
+
+    const root = ReactDOM.createRoot(document.createElement('div'));
+    utils.act(() => root.render(<App />));
+    utils.act(() => store.profilerStore.startProfiling());
+    utils.act(() => setChildUnmounted(true));
+    utils.act(() => store.profilerStore.stopProfiling());
+
+    const updaters = store.profilerStore.getCommitData(store.roots[0], 0)
+      .updaters;
+    expect(updaters.length).toEqual(1);
+    expect(updaters[0].displayName).toEqual('App');
+  });
+
+  it('components in a deleted subtree and added to updaters during the layout phase should not crash', () => {
+    let setChildUnmounted;
+    function Child() {
+      return <GrandChild />;
+    }
+
+    function GrandChild() {
+      const [, setState] = React.useState(false);
+
+      React.useLayoutEffect(() => {
+        return () => setState(true);
+      });
+
+      return null;
+    }
+
+    function App() {
+      const [childUnmounted, _setChildUnmounted] = React.useState(false);
+      setChildUnmounted = _setChildUnmounted;
+      return <>{!childUnmounted && <Child />}</>;
+    }
+
+    const root = ReactDOM.createRoot(document.createElement('div'));
+    utils.act(() => root.render(<App />));
+    utils.act(() => store.profilerStore.startProfiling());
+    utils.act(() => setChildUnmounted(true));
+    utils.act(() => store.profilerStore.stopProfiling());
+
+    const updaters = store.profilerStore.getCommitData(store.roots[0], 0)
+      .updaters;
+    expect(updaters.length).toEqual(1);
+    expect(updaters[0].displayName).toEqual('App');
+  });
+
+  it('components that were deleted should not be added to updaters during the passive phase', () => {
+    let setChildUnmounted;
+    function Child() {
+      const [, setState] = React.useState(false);
+      React.useEffect(() => {
+        return () => setState(true);
+      });
+
+      return null;
+    }
+
+    function App() {
+      const [childUnmounted, _setChildUnmounted] = React.useState(false);
+      setChildUnmounted = _setChildUnmounted;
+      return <>{!childUnmounted && <Child />}</>;
+    }
+
+    const root = ReactDOM.createRoot(document.createElement('div'));
+    utils.act(() => root.render(<App />));
+    utils.act(() => store.profilerStore.startProfiling());
+    utils.act(() => setChildUnmounted(true));
+    utils.act(() => store.profilerStore.stopProfiling());
+
+    const updaters = store.profilerStore.getCommitData(store.roots[0], 0)
+      .updaters;
+    expect(updaters.length).toEqual(1);
+    expect(updaters[0].displayName).toEqual('App');
+  });
 });

filename: packages/react-devtools-shared/src/backend/renderer.js
patch: @@ -2586,7 +2586,9 @@ export function attach(
 
   function getUpdatersList(root): Array<SerializedElement> | null {
     return root.memoizedUpdaters != null
-      ? Array.from(root.memoizedUpdaters).map(fiberToSerializedElement)
+      ? Array.from(root.memoizedUpdaters)
+          .filter(fiber => getFiberIDUnsafe(fiber) !== null)
+          .map(fiberToSerializedElement)
       : null;
   }