[Draft] Add feature flag: enableStrongMemoryCleanup

Author: bgirard

packages/react-reconciler/src/ReactFiberCommitWork.new.js

@@ -35,6 +35,7 @@ import {
   enableSuspenseCallback,
   enableScopeAPI,
   enableStrictEffects,
+  enableStrongMemoryCleanup,
 } from 'shared/ReactFeatureFlags';
 import {
   FunctionComponent,
@@ -1212,9 +1213,28 @@ function detachFiberMutation(fiber: Fiber) {
   fiber.return = null;
 }
 
-export function detachFiberAfterEffects(fiber: Fiber): void {
+export function detachFiberAfterEffects(
+  fiber: Fiber,
+  recurseIntoSibbling: ?boolean,
+): void {
   // Null out fields to improve GC for references that may be lingering (e.g. DevTools).
   // Note that we already cleared the return pointer in detachFiberMutation().
+  if (enableStrongMemoryCleanup) {
+    if (fiber.child) {
+      detachFiberAfterEffects(fiber.child, true);
+    }
+    if (fiber.sibling && recurseIntoSibbling === true) {
+      detachFiberAfterEffects(fiber.sibling, true);
+    }
+    if (fiber.stateNode) {
+      Object.keys(fiber.stateNode).forEach(key => {
+        if (key.indexOf('__react') === 0) {
+          delete fiber.stateNode[key];
+        }
+      });
+    }
+    fiber.return = null;
+  }
   fiber.alternate = null;
   fiber.child = null;
   fiber.deletions = null;

packages/react-reconciler/src/ReactFiberCommitWork.old.js

@@ -35,6 +35,7 @@ import {
   enableSuspenseCallback,
   enableScopeAPI,
   enableStrictEffects,
+  enableStrongMemoryCleanup,
 } from 'shared/ReactFeatureFlags';
 import {
   FunctionComponent,
@@ -1212,9 +1213,28 @@ function detachFiberMutation(fiber: Fiber) {
   fiber.return = null;
 }
 
-export function detachFiberAfterEffects(fiber: Fiber): void {
+export function detachFiberAfterEffects(
+  fiber: Fiber,
+  recurseIntoSibbling: ?boolean,
+): void {
   // Null out fields to improve GC for references that may be lingering (e.g. DevTools).
   // Note that we already cleared the return pointer in detachFiberMutation().
+  if (enableStrongMemoryCleanup) {
+    if (fiber.child) {
+      detachFiberAfterEffects(fiber.child, true);
+    }
+    if (fiber.sibling && recurseIntoSibbling === true) {
+      detachFiberAfterEffects(fiber.sibling, true);
+    }
+    if (fiber.stateNode) {
+      Object.keys(fiber.stateNode).forEach(key => {
+        if (key.indexOf('__react') === 0) {
+          delete fiber.stateNode[key];
+        }
+      });
+    }
+    fiber.return = null;
+  }
   fiber.alternate = null;
   fiber.child = null;
   fiber.deletions = null;

packages/shared/ReactFeatureFlags.js

@@ -112,6 +112,8 @@ export const disableNativeComponentFrames = false;
 // If there are no still-mounted boundaries, the errors should be rethrown.
 export const skipUnmountedBoundaries = false;
 
+export const enableStrongMemoryCleanup = true;
+
 // --------------------------
 // Future APIs to be deprecated
 // --------------------------

packages/shared/forks/ReactFeatureFlags.native-fb.js

@@ -46,6 +46,7 @@ export const enableLegacyFBSupport = false;
 export const enableFilterEmptyStringAttributesDOM = false;
 export const disableNativeComponentFrames = false;
 export const skipUnmountedBoundaries = false;
+export const enableStrongMemoryCleanup = true;
 
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;

packages/shared/forks/ReactFeatureFlags.native-oss.js

@@ -45,6 +45,7 @@ export const enableLegacyFBSupport = false;
 export const enableFilterEmptyStringAttributesDOM = false;
 export const disableNativeComponentFrames = false;
 export const skipUnmountedBoundaries = false;
+export const enableStrongMemoryCleanup = true;
 
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;

packages/shared/forks/ReactFeatureFlags.test-renderer.js

@@ -45,6 +45,7 @@ export const enableLegacyFBSupport = false;
 export const enableFilterEmptyStringAttributesDOM = false;
 export const disableNativeComponentFrames = false;
 export const skipUnmountedBoundaries = false;
+export const enableStrongMemoryCleanup = true;
 
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;

packages/shared/forks/ReactFeatureFlags.test-renderer.native.js

@@ -45,6 +45,7 @@ export const enableLegacyFBSupport = false;
 export const enableFilterEmptyStringAttributesDOM = false;
 export const disableNativeComponentFrames = false;
 export const skipUnmountedBoundaries = false;
+export const enableStrongMemoryCleanup = true;
 
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;

packages/shared/forks/ReactFeatureFlags.test-renderer.www.js

@@ -45,6 +45,7 @@ export const enableLegacyFBSupport = false;
 export const enableFilterEmptyStringAttributesDOM = false;
 export const disableNativeComponentFrames = false;
 export const skipUnmountedBoundaries = false;
+export const enableStrongMemoryCleanup = true;
 
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;

packages/shared/forks/ReactFeatureFlags.testing.js

@@ -45,6 +45,7 @@ export const enableLegacyFBSupport = false;
 export const enableFilterEmptyStringAttributesDOM = false;
 export const disableNativeComponentFrames = false;
 export const skipUnmountedBoundaries = false;
+export const enableStrongMemoryCleanup = true;
 
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;

packages/shared/forks/ReactFeatureFlags.testing.www.js

@@ -45,6 +45,7 @@ export const enableLegacyFBSupport = !__EXPERIMENTAL__;
 export const enableFilterEmptyStringAttributesDOM = false;
 export const disableNativeComponentFrames = false;
 export const skipUnmountedBoundaries = true;
+export const enableStrongMemoryCleanup = true;
 
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;

packages/shared/forks/ReactFeatureFlags.www-dynamic.js

@@ -52,6 +52,7 @@ export const disableNativeComponentFrames = false;
 export const createRootStrictEffectsByDefault = false;
 export const enableStrictEffects = false;
 export const enableUseRefAccessWarning = __VARIANT__;
+export const enableStrongMemoryCleanup = __VARIANT__;
 
 export const enableProfilerNestedUpdateScheduledHook = __VARIANT__;
 export const disableSchedulerTimeoutInWorkLoop = __VARIANT__;

packages/shared/forks/ReactFeatureFlags.www.js

@@ -33,6 +33,7 @@ export const {
   disableSchedulerTimeoutInWorkLoop,
   enableSyncMicroTasks,
   enableLazyContextPropagation,
+  enableStrongMemoryCleanup,
 } = dynamicFeatureFlags;
 
 // On WWW, __EXPERIMENTAL__ is used for a new modern build.