Update on "Fix useMemoCache with setState in render"

Fixes the bug that alexmckenley and mofeiZ found where setState-in-render can reset useMemoCache and cause an infinite loop. The bug was that renderWithHooksAgain() was not resetting hook state when rerendering (so useMemo values were preserved) but was resetting the updateQueue. This meant that the entire memo cache was cleared on a setState-in-render.

The fix here is to call a new helper function to clear the update queue. It nulls out other properties, but for memoCache it just sets the index back to zero.

[ghstack-poisoned]

packages/react-reconciler/src/ReactFiberHooks.js

@@ -770,6 +770,11 @@ export function replaySuspendedComponentWithHooks<Props, SecondArg>(
     ignorePreviousDependencies =
       current !== null && current.type !== workInProgress.type;
   }
+  // renderWithHooks only resets the updateQueue but does not clear it, since
+  // it needs to work for both this case (suspense replay) as well as for double
+  // renders in dev and setState-in-render. However, for the suspense replay case
+  // we need to reset the updateQueue to correctly handle unmount effects, so we
+  // clear the queue here
   workInProgress.updateQueue = null;
   const children = renderWithHooksAgain(
     workInProgress,