mirror of
https://github.com/facebook/react.git
synced 2025-11-01 09:12:30 +00:00
Samuel Susla
2cd3c424ea
This is a fix for a problem where React retains shadow nodes longer than it needs to. The behaviour is shown in React Native test: https://github.com/facebook/react-native/blob/main/packages/react-native/src/private/__tests__/utilities/__tests__/ShadowNodeReferenceCounter-itest.js#L169 When React commits a new shadow tree, old shadow nodes are stored inside `fiber.alternate.stateNode`. This is not cleared up until React clones the node again. This may be problematic if mutation deletes a subtree, in that case `fiber.alternate.stateNode` will retain entire subtree until next update. In case of image nodes, this means retaining entire images. So when React goes from revision A: `<View><View /></View>` to revision B: `<View />`, `fiber.alternate.stateNode` will be pointing to Shadow Node that represents revision A..  To fix this, this PR adds a new feature flag `enableEagerAlternateStateNodeCleanup`. When enabled, `alternate.stateNode` is proactively pointed towards finishedWork's stateNode, releasing resources sooner. I have verified this fixes the issue [demonstrated by React Native tests](https://github.com/facebook/react-native/blob/main/packages/react-native/src/private/__tests__/utilities/__tests__/ShadowNodeReferenceCounter-itest.js#L169). All existing React tests pass when the flag is enabled.
91 lines
3.8 KiB
JavaScript
91 lines
3.8 KiB
JavaScript
/**
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @flow
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*/
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import typeof * as FeatureFlagsType from 'shared/ReactFeatureFlags';
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import typeof * as ExportsType from './ReactFeatureFlags.native-fb';
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import typeof * as DynamicExportsType from './ReactFeatureFlags.native-fb-dynamic';
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// Re-export dynamic flags from the internal module.
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// Intentionally using * because this import is compiled to a `require` call.
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import * as dynamicFlagsUntyped from 'ReactNativeInternalFeatureFlags';
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const dynamicFlags: DynamicExportsType = (dynamicFlagsUntyped: any);
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// We destructure each value before re-exporting to avoid a dynamic look-up on
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// the exports object every time a flag is read.
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export const {
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alwaysThrottleRetries,
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enableHiddenSubtreeInsertionEffectCleanup,
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enableObjectFiber,
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enablePersistedModeClonedFlag,
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enableShallowPropDiffing,
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enableUseEffectCRUDOverload,
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enableEagerAlternateStateNodeCleanup,
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passChildrenWhenCloningPersistedNodes,
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enableSiblingPrerendering,
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enableFastAddPropertiesInDiffing,
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enableLazyPublicInstanceInFabric,
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renameElementSymbol,
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ownerStackLimit,
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} = dynamicFlags;
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// The rest of the flags are static for better dead code elimination.
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export const disableClientCache = true;
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export const disableCommentsAsDOMContainers = true;
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export const disableDefaultPropsExceptForClasses = true;
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export const disableInputAttributeSyncing = false;
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export const disableLegacyContext = false;
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export const disableLegacyContextForFunctionComponents = false;
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export const disableLegacyMode = false;
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export const disableSchedulerTimeoutInWorkLoop = false;
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export const disableTextareaChildren = false;
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export const enableAsyncDebugInfo = false;
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export const enableAsyncIterableChildren = false;
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export const enableCPUSuspense = true;
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export const enableCreateEventHandleAPI = false;
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export const enableDO_NOT_USE_disableStrictPassiveEffect = false;
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export const enableMoveBefore = true;
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export const enableFizzExternalRuntime = true;
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export const enableHalt = false;
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export const enableInfiniteRenderLoopDetection = false;
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export const enableLegacyCache = false;
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export const enableLegacyFBSupport = false;
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export const enableLegacyHidden = false;
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export const enableNoCloningMemoCache = false;
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export const enablePostpone = false;
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export const enableProfilerCommitHooks = __PROFILE__;
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export const enableProfilerNestedUpdatePhase = __PROFILE__;
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export const enableProfilerTimer = __PROFILE__;
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export const enableReactTestRendererWarning = false;
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export const enableRenderableContext = true;
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export const enableRetryLaneExpiration = false;
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export const enableSchedulingProfiler = __PROFILE__;
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export const enableComponentPerformanceTrack = false;
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export const enableScopeAPI = false;
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export const enableSuspenseAvoidThisFallback = false;
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export const enableSuspenseCallback = true;
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export const enableTaint = true;
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export const enableTransitionTracing = false;
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export const enableTrustedTypesIntegration = false;
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export const enableUpdaterTracking = __PROFILE__;
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export const enableUseEffectEventHook = false;
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export const favorSafetyOverHydrationPerf = true;
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export const retryLaneExpirationMs = 5000;
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export const syncLaneExpirationMs = 250;
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export const transitionLaneExpirationMs = 5000;
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export const enableHydrationLaneScheduling = true;
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export const enableYieldingBeforePassive = false;
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export const enableThrottledScheduling = false;
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export const enableViewTransition = false;
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export const enableSwipeTransition = false;
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export const enableScrollEndPolyfill = true;
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export const enableFragmentRefs = false;
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// Flow magic to verify the exports of this file match the original version.
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((((null: any): ExportsType): FeatureFlagsType): ExportsType);
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