Flush all passive destroy fns before calling create fns (facebook#17947)

Brian Vaughn · web-flow · commit f7278034de5a · 2020-02-11T09:52:54.000-08:00
* Flush all passive destroy fns before calling create fns

Previously we only flushed destroy functions for a single fiber.

The reason this is important is that interleaving destroy/create effects between sibling components might cause components to interfere with each other (e.g. a destroy function in one component may unintentionally override a ref value set by a create function in another component).

This PR builds on top of the recently added deferPassiveEffectCleanupDuringUnmount kill switch to separate passive effects flushing into two separate phases (similar to layout effects).

* Change passive effect flushing to use arrays instead of lists

This change offers a small advantage over the way we did things previous: it continues invoking destroy functions even after a previous one errored.
diff --git a/packages/react-reconciler/src/ReactFiberCommitWork.js b/packages/react-reconciler/src/ReactFiberCommitWork.js
@@ -110,7 +110,8 @@ import {
   captureCommitPhaseError,
   resolveRetryThenable,
   markCommitTimeOfFallback,
-  enqueuePendingPassiveEffectDestroyFn,
+  enqueuePendingPassiveHookEffectMount,
+  enqueuePendingPassiveHookEffectUnmount,
 } from './ReactFiberWorkLoop';
 import {
   NoEffect as NoHookEffect,
@@ -396,6 +397,28 @@ function commitHookEffectListMount(tag: number, finishedWork: Fiber) {
   }
 }
 
+function schedulePassiveEffects(finishedWork: Fiber) {
+  if (deferPassiveEffectCleanupDuringUnmount) {
+    const updateQueue: FunctionComponentUpdateQueue | null = (finishedWork.updateQueue: any);
+    let lastEffect = updateQueue !== null ? updateQueue.lastEffect : null;
+    if (lastEffect !== null) {
+      const firstEffect = lastEffect.next;
+      let effect = firstEffect;
+      do {
+        const {next, tag} = effect;
+        if (
+          (tag & HookPassive) !== NoHookEffect &&
+          (tag & HookHasEffect) !== NoHookEffect
+        ) {
+          enqueuePendingPassiveHookEffectUnmount(finishedWork, effect);
+          enqueuePendingPassiveHookEffectMount(finishedWork, effect);
+        }
+        effect = next;
+      } while (effect !== firstEffect);
+    }
+  }
+}
+
 export function commitPassiveHookEffects(finishedWork: Fiber): void {
   if ((finishedWork.effectTag & Passive) !== NoEffect) {
     switch (finishedWork.tag) {
@@ -432,6 +455,10 @@ function commitLifeCycles(
       // e.g. a destroy function in one component should never override a ref set
       // by a create function in another component during the same commit.
       commitHookEffectListMount(HookLayout | HookHasEffect, finishedWork);
+
+      if (deferPassiveEffectCleanupDuringUnmount) {
+        schedulePassiveEffects(finishedWork);
+      }
       return;
     }
     case ClassComponent: {
@@ -774,7 +801,7 @@ function commitUnmount(
               const {destroy, tag} = effect;
               if (destroy !== undefined) {
                 if ((tag & HookPassive) !== NoHookEffect) {
-                  enqueuePendingPassiveEffectDestroyFn(destroy);
+                  enqueuePendingPassiveHookEffectUnmount(current, effect);
                 } else {
                   safelyCallDestroy(current, destroy);
                 }
diff --git a/packages/react-reconciler/src/ReactFiberHooks.js b/packages/react-reconciler/src/ReactFiberHooks.js
@@ -144,7 +144,7 @@ export type Hook = {|
   next: Hook | null,
 |};
 
-type Effect = {|
+export type Effect = {|
   tag: HookEffectTag,
   create: () => (() => void) | void,
   destroy: (() => void) | void,
diff --git a/packages/react-reconciler/src/ReactFiberWorkLoop.js b/packages/react-reconciler/src/ReactFiberWorkLoop.js
@@ -14,6 +14,7 @@ import type {ReactPriorityLevel} from './SchedulerWithReactIntegration';
 import type {Interaction} from 'scheduler/src/Tracing';
 import type {SuspenseConfig} from './ReactFiberSuspenseConfig';
 import type {SuspenseState} from './ReactFiberSuspenseComponent';
+import type {Effect as HookEffect} from './ReactFiberHooks';
 
 import {
   warnAboutDeprecatedLifecycles,
@@ -257,7 +258,8 @@ let rootDoesHavePassiveEffects: boolean = false;
 let rootWithPendingPassiveEffects: FiberRoot | null = null;
 let pendingPassiveEffectsRenderPriority: ReactPriorityLevel = NoPriority;
 let pendingPassiveEffectsExpirationTime: ExpirationTime = NoWork;
-let pendingUnmountedPassiveEffectDestroyFunctions: Array<() => void> = [];
+let pendingPassiveHookEffectsMount: Array<HookEffect | Fiber> = [];
+let pendingPassiveHookEffectsUnmount: Array<HookEffect | Fiber> = [];
 
 let rootsWithPendingDiscreteUpdates: Map<
   FiberRoot,
@@ -2168,11 +2170,28 @@ export function flushPassiveEffects() {
   }
 }
 
-export function enqueuePendingPassiveEffectDestroyFn(
-  destroy: () => void,
+export function enqueuePendingPassiveHookEffectMount(
+  fiber: Fiber,
+  effect: HookEffect,
+): void {
+  if (deferPassiveEffectCleanupDuringUnmount) {
+    pendingPassiveHookEffectsMount.push(effect, fiber);
+    if (!rootDoesHavePassiveEffects) {
+      rootDoesHavePassiveEffects = true;
+      scheduleCallback(NormalPriority, () => {
+        flushPassiveEffects();
+        return null;
+      });
+    }
+  }
+}
+
+export function enqueuePendingPassiveHookEffectUnmount(
+  fiber: Fiber,
+  effect: HookEffect,
 ): void {
   if (deferPassiveEffectCleanupDuringUnmount) {
-    pendingUnmountedPassiveEffectDestroyFunctions.push(destroy);
+    pendingPassiveHookEffectsUnmount.push(effect, fiber);
     if (!rootDoesHavePassiveEffects) {
       rootDoesHavePassiveEffects = true;
       scheduleCallback(NormalPriority, () => {
@@ -2183,6 +2202,11 @@ export function enqueuePendingPassiveEffectDestroyFn(
   }
 }
 
+function invokePassiveEffectCreate(effect: HookEffect): void {
+  const create = effect.create;
+  effect.destroy = create();
+}
+
 function flushPassiveEffectsImpl() {
   if (rootWithPendingPassiveEffects === null) {
     return false;
@@ -2201,45 +2225,95 @@ function flushPassiveEffectsImpl() {
   const prevInteractions = pushInteractions(root);
 
   if (deferPassiveEffectCleanupDuringUnmount) {
-    // Flush any pending passive effect destroy functions that belong to
-    // components that were unmounted during the most recent commit.
-    for (
-      let i = 0;
-      i < pendingUnmountedPassiveEffectDestroyFunctions.length;
-      i++
-    ) {
-      const destroy = pendingUnmountedPassiveEffectDestroyFunctions[i];
-      invokeGuardedCallback(null, destroy, null);
+    // It's important that ALL pending passive effect destroy functions are called
+    // before ANY passive effect create functions are called.
+    // Otherwise effects in sibling components might interfere with each other.
+    // e.g. a destroy function in one component may unintentionally override a ref
+    // value set by a create function in another component.
+    // Layout effects have the same constraint.
+
+    // First pass: Destroy stale passive effects.
+    let unmountEffects = pendingPassiveHookEffectsUnmount;
+    pendingPassiveHookEffectsUnmount = [];
+    for (let i = 0; i < unmountEffects.length; i += 2) {
+      const effect = ((unmountEffects[i]: any): HookEffect);
+      const fiber = ((unmountEffects[i + 1]: any): Fiber);
+      const destroy = effect.destroy;
+      effect.destroy = undefined;
+      if (typeof destroy === 'function') {
+        if (__DEV__) {
+          setCurrentDebugFiberInDEV(fiber);
+          invokeGuardedCallback(null, destroy, null);
+          if (hasCaughtError()) {
+            invariant(fiber !== null, 'Should be working on an effect.');
+            const error = clearCaughtError();
+            captureCommitPhaseError(fiber, error);
+          }
+          resetCurrentDebugFiberInDEV();
+        } else {
+          try {
+            destroy();
+          } catch (error) {
+            invariant(fiber !== null, 'Should be working on an effect.');
+            captureCommitPhaseError(fiber, error);
+          }
+        }
+      }
     }
-    pendingUnmountedPassiveEffectDestroyFunctions.length = 0;
-  }
 
-  // Note: This currently assumes there are no passive effects on the root
-  // fiber, because the root is not part of its own effect list. This could
-  // change in the future.
-  let effect = root.current.firstEffect;
-  while (effect !== null) {
-    if (__DEV__) {
-      setCurrentDebugFiberInDEV(effect);
-      invokeGuardedCallback(null, commitPassiveHookEffects, null, effect);
-      if (hasCaughtError()) {
-        invariant(effect !== null, 'Should be working on an effect.');
-        const error = clearCaughtError();
-        captureCommitPhaseError(effect, error);
+    // Second pass: Create new passive effects.
+    let mountEffects = pendingPassiveHookEffectsMount;
+    pendingPassiveHookEffectsMount = [];
+    for (let i = 0; i < mountEffects.length; i += 2) {
+      const effect = ((mountEffects[i]: any): HookEffect);
+      const fiber = ((mountEffects[i + 1]: any): Fiber);
+      if (__DEV__) {
+        setCurrentDebugFiberInDEV(fiber);
+        invokeGuardedCallback(null, invokePassiveEffectCreate, null, effect);
+        if (hasCaughtError()) {
+          invariant(fiber !== null, 'Should be working on an effect.');
+          const error = clearCaughtError();
+          captureCommitPhaseError(fiber, error);
+        }
+        resetCurrentDebugFiberInDEV();
+      } else {
+        try {
+          const create = effect.create;
+          effect.destroy = create();
+        } catch (error) {
+          invariant(fiber !== null, 'Should be working on an effect.');
+          captureCommitPhaseError(fiber, error);
+        }
       }
-      resetCurrentDebugFiberInDEV();
-    } else {
-      try {
-        commitPassiveHookEffects(effect);
-      } catch (error) {
-        invariant(effect !== null, 'Should be working on an effect.');
-        captureCommitPhaseError(effect, error);
+    }
+  } else {
+    // Note: This currently assumes there are no passive effects on the root fiber
+    // because the root is not part of its own effect list.
+    // This could change in the future.
+    let effect = root.current.firstEffect;
+    while (effect !== null) {
+      if (__DEV__) {
+        setCurrentDebugFiberInDEV(effect);
+        invokeGuardedCallback(null, commitPassiveHookEffects, null, effect);
+        if (hasCaughtError()) {
+          invariant(effect !== null, 'Should be working on an effect.');
+          const error = clearCaughtError();
+          captureCommitPhaseError(effect, error);
+        }
+        resetCurrentDebugFiberInDEV();
+      } else {
+        try {
+          commitPassiveHookEffects(effect);
+        } catch (error) {
+          invariant(effect !== null, 'Should be working on an effect.');
+          captureCommitPhaseError(effect, error);
+        }
       }
+      const nextNextEffect = effect.nextEffect;
+      // Remove nextEffect pointer to assist GC
+      effect.nextEffect = null;
+      effect = nextNextEffect;
     }
-    const nextNextEffect = effect.nextEffect;
-    // Remove nextEffect pointer to assist GC
-    effect.nextEffect = null;
-    effect = nextNextEffect;
   }
 
   if (enableSchedulerTracing) {
diff --git a/packages/react-reconciler/src/__tests__/ReactHooksWithNoopRenderer-test.internal.js b/packages/react-reconciler/src/__tests__/ReactHooksWithNoopRenderer-test.internal.js
@@ -1558,6 +1558,67 @@ describe('ReactHooksWithNoopRenderer', () => {
       ]);
     });
 
+    it('unmounts all previous effects between siblings before creating any new ones', () => {
+      function Counter({count, label}) {
+        useEffect(() => {
+          Scheduler.unstable_yieldValue(`Mount ${label} [${count}]`);
+          return () => {
+            Scheduler.unstable_yieldValue(`Unmount ${label} [${count}]`);
+          };
+        });
+        return <Text text={`${label} ${count}`} />;
+      }
+      act(() => {
+        ReactNoop.render(
+          <React.Fragment>
+            <Counter label="A" count={0} />
+            <Counter label="B" count={0} />
+          </React.Fragment>,
+          () => Scheduler.unstable_yieldValue('Sync effect'),
+        );
+        expect(Scheduler).toFlushAndYieldThrough(['A 0', 'B 0', 'Sync effect']);
+        expect(ReactNoop.getChildren()).toEqual([span('A 0'), span('B 0')]);
+      });
+
+      expect(Scheduler).toHaveYielded(['Mount A [0]', 'Mount B [0]']);
+
+      act(() => {
+        ReactNoop.render(
+          <React.Fragment>
+            <Counter label="A" count={1} />
+            <Counter label="B" count={1} />
+          </React.Fragment>,
+          () => Scheduler.unstable_yieldValue('Sync effect'),
+        );
+        expect(Scheduler).toFlushAndYieldThrough(['A 1', 'B 1', 'Sync effect']);
+        expect(ReactNoop.getChildren()).toEqual([span('A 1'), span('B 1')]);
+      });
+      expect(Scheduler).toHaveYielded([
+        'Unmount A [0]',
+        'Unmount B [0]',
+        'Mount A [1]',
+        'Mount B [1]',
+      ]);
+
+      act(() => {
+        ReactNoop.render(
+          <React.Fragment>
+            <Counter label="B" count={2} />
+            <Counter label="C" count={0} />
+          </React.Fragment>,
+          () => Scheduler.unstable_yieldValue('Sync effect'),
+        );
+        expect(Scheduler).toFlushAndYieldThrough(['B 2', 'C 0', 'Sync effect']);
+        expect(ReactNoop.getChildren()).toEqual([span('B 2'), span('C 0')]);
+      });
+      expect(Scheduler).toHaveYielded([
+        'Unmount A [1]',
+        'Unmount B [1]',
+        'Mount B [2]',
+        'Mount C [0]',
+      ]);
+    });
+
     it('handles errors on mount', () => {
       function Counter(props) {
         useEffect(() => {
@@ -1656,8 +1717,6 @@ describe('ReactHooksWithNoopRenderer', () => {
           return () => {
             Scheduler.unstable_yieldValue('Oops!');
             throw new Error('Oops!');
-            // eslint-disable-next-line no-unreachable
-            Scheduler.unstable_yieldValue(`Unmount A [${props.count}]`);
           };
         });
         useEffect(() => {
@@ -1668,6 +1727,7 @@ describe('ReactHooksWithNoopRenderer', () => {
         });
         return <Text text={'Count: ' + props.count} />;
       }
+
       act(() => {
         ReactNoop.render(<Counter count={0} />, () =>
           Scheduler.unstable_yieldValue('Sync effect'),
@@ -1679,18 +1739,30 @@ describe('ReactHooksWithNoopRenderer', () => {
       });
 
       act(() => {
-        // This update will trigger an error
+        // This update will trigger an error during passive effect unmount
         ReactNoop.render(<Counter count={1} />, () =>
           Scheduler.unstable_yieldValue('Sync effect'),
         );
         expect(Scheduler).toFlushAndYieldThrough(['Count: 1', 'Sync effect']);
         expect(ReactNoop.getChildren()).toEqual([span('Count: 1')]);
         expect(() => ReactNoop.flushPassiveEffects()).toThrow('Oops');
-        expect(Scheduler).toHaveYielded(['Oops!']);
+
+        // This tests enables a feature flag that flushes all passive destroys in a
+        // separate pass before flushing any passive creates.
+        // A result of this two-pass flush is that an error thrown from unmount does
+        // not block the subsequent create functions from being run.
+        expect(Scheduler).toHaveYielded([
+          'Oops!',
+          'Unmount B [0]',
+          'Mount A [1]',
+          'Mount B [1]',
+        ]);
       });
-      // B unmounts even though an error was thrown in the previous effect
-      // B's destroy function runs later on unmount though, since it's passive
-      expect(Scheduler).toHaveYielded(['Unmount B [0]']);
+
+      // <Counter> gets unmounted because an error is thrown above.
+      // The remaining destroy functions are run later on unmount, since they're passive.
+      // In this case, one of them throws again (because of how the test is written).
+      expect(Scheduler).toHaveYielded(['Oops!', 'Unmount B [1]']);
       expect(ReactNoop.getChildren()).toEqual([]);
     });
 
