Revert Rerender Error Check (facebook#17519)

sebmarkbage · web-flow · commit 5064c7f6aa2b · 2019-12-03T23:10:36.000-08:00
* Add failing test * Revert "Move rerender error check to avoid global state" This reverts commit 3e77742.
diff --git a/packages/react-reconciler/src/ReactFiberHooks.js b/packages/react-reconciler/src/ReactFiberHooks.js
@@ -198,7 +198,8 @@ let renderPhaseUpdates: Map<
   UpdateQueue<any, any>,
   Update<any, any>,
 > | null = null;
-
+// Counter to prevent infinite loops.
+let numberOfReRenders: number = 0;
 const RE_RENDER_LIMIT = 25;
 
 // In DEV, this is the name of the currently executing primitive hook
@@ -397,6 +398,7 @@ export function renderWithHooks(
 
   // didScheduleRenderPhaseUpdate = false;
   // renderPhaseUpdates = null;
+  // numberOfReRenders = 0;
 
   // TODO Warn if no hooks are used at all during mount, then some are used during update.
   // Currently we will identify the update render as a mount because memoizedState === null.
@@ -428,17 +430,8 @@ export function renderWithHooks(
   let children = Component(props, refOrContext);
 
   if (didScheduleRenderPhaseUpdate) {
-    // Counter to prevent infinite loops.
-    let numberOfReRenders: number = 0;
     do {
       didScheduleRenderPhaseUpdate = false;
-
-      invariant(
-        numberOfReRenders < RE_RENDER_LIMIT,
-        'Too many re-renders. React limits the number of renders to prevent ' +
-          'an infinite loop.',
-      );
-
       numberOfReRenders += 1;
       if (__DEV__) {
         // Even when hot reloading, allow dependencies to stabilize
@@ -465,6 +458,7 @@ export function renderWithHooks(
     } while (didScheduleRenderPhaseUpdate);
 
     renderPhaseUpdates = null;
+    numberOfReRenders = 0;
   }
 
   // We can assume the previous dispatcher is always this one, since we set it
@@ -495,6 +489,7 @@ export function renderWithHooks(
   // These were reset above
   // didScheduleRenderPhaseUpdate = false;
   // renderPhaseUpdates = null;
+  // numberOfReRenders = 0;
 
   invariant(
     !didRenderTooFewHooks,
@@ -541,6 +536,7 @@ export function resetHooks(): void {
 
   didScheduleRenderPhaseUpdate = false;
   renderPhaseUpdates = null;
+  numberOfReRenders = 0;
 }
 
 function mountWorkInProgressHook(): Hook {
@@ -676,43 +672,45 @@ function updateReducer<S, I, A>(
 
   queue.lastRenderedReducer = reducer;
 
-  if (renderPhaseUpdates !== null) {
+  if (numberOfReRenders > 0) {
     // This is a re-render. Apply the new render phase updates to the previous
     // work-in-progress hook.
     const dispatch: Dispatch<A> = (queue.dispatch: any);
-    // Render phase updates are stored in a map of queue -> linked list
-    const firstRenderPhaseUpdate = renderPhaseUpdates.get(queue);
-    if (firstRenderPhaseUpdate !== undefined) {
-      renderPhaseUpdates.delete(queue);
-      let newState = hook.memoizedState;
-      let update = firstRenderPhaseUpdate;
-      do {
-        // Process this render phase update. We don't have to check the
-        // priority because it will always be the same as the current
-        // render's.
-        const action = update.action;
-        newState = reducer(newState, action);
-        update = update.next;
-      } while (update !== null);
-
-      // Mark that the fiber performed work, but only if the new state is
-      // different from the current state.
-      if (!is(newState, hook.memoizedState)) {
-        markWorkInProgressReceivedUpdate();
-      }
+    if (renderPhaseUpdates !== null) {
+      // Render phase updates are stored in a map of queue -> linked list
+      const firstRenderPhaseUpdate = renderPhaseUpdates.get(queue);
+      if (firstRenderPhaseUpdate !== undefined) {
+        renderPhaseUpdates.delete(queue);
+        let newState = hook.memoizedState;
+        let update = firstRenderPhaseUpdate;
+        do {
+          // Process this render phase update. We don't have to check the
+          // priority because it will always be the same as the current
+          // render's.
+          const action = update.action;
+          newState = reducer(newState, action);
+          update = update.next;
+        } while (update !== null);
 
-      hook.memoizedState = newState;
-      // Don't persist the state accumulated from the render phase updates to
-      // the base state unless the queue is empty.
-      // TODO: Not sure if this is the desired semantics, but it's what we
-      // do for gDSFP. I can't remember why.
-      if (hook.baseUpdate === queue.last) {
-        hook.baseState = newState;
-      }
+        // Mark that the fiber performed work, but only if the new state is
+        // different from the current state.
+        if (!is(newState, hook.memoizedState)) {
+          markWorkInProgressReceivedUpdate();
+        }
+
+        hook.memoizedState = newState;
+        // Don't persist the state accumulated from the render phase updates to
+        // the base state unless the queue is empty.
+        // TODO: Not sure if this is the desired semantics, but it's what we
+        // do for gDSFP. I can't remember why.
+        if (hook.baseUpdate === queue.last) {
+          hook.baseState = newState;
+        }
 
-      queue.lastRenderedState = newState;
+        queue.lastRenderedState = newState;
 
-      return [newState, dispatch];
+        return [newState, dispatch];
+      }
     }
     return [hook.memoizedState, dispatch];
   }
@@ -1205,6 +1203,12 @@ function dispatchAction<S, A>(
   queue: UpdateQueue<S, A>,
   action: A,
 ) {
+  invariant(
+    numberOfReRenders < RE_RENDER_LIMIT,
+    'Too many re-renders. React limits the number of renders to prevent ' +
+      'an infinite loop.',
+  );
+
   if (__DEV__) {
     warning(
       typeof arguments[3] !== 'function',
diff --git a/packages/react-reconciler/src/__tests__/ReactHooksWithNoopRenderer-test.internal.js b/packages/react-reconciler/src/__tests__/ReactHooksWithNoopRenderer-test.internal.js
@@ -2493,4 +2493,35 @@ describe('ReactHooksWithNoopRenderer', () => {
     expect(Scheduler).toHaveYielded(['Step: 5, Shadow: 5']);
     expect(ReactNoop).toMatchRenderedOutput('5');
   });
+
+  it('should process the rest pending updates after a render phase update', () => {
+    // Similar to previous test, except using a preceding render phase update
+    // instead of new props.
+    let updateA;
+    let updateC;
+    function App() {
+      const [a, setA] = useState(false);
+      const [b, setB] = useState(false);
+      if (a !== b) {
+        setB(a);
+      }
+      // Even though we called setB above,
+      // we should still apply the changes to C,
+      // during this render pass.
+      const [c, setC] = useState(false);
+      updateA = setA;
+      updateC = setC;
+      return `${a ? 'A' : 'a'}${b ? 'B' : 'b'}${c ? 'C' : 'c'}`;
+    }
+
+    act(() => ReactNoop.render(<App />));
+    expect(ReactNoop).toMatchRenderedOutput('abc');
+
+    act(() => {
+      updateA(true);
+      // This update should not get dropped.
+      updateC(true);
+    });
+    expect(ReactNoop).toMatchRenderedOutput('ABC');
+  });
 });
