packages/react-debug-tools/src/ReactDebugHooks.js

@@ -7,13 +7,7 @@
  * @flow
  */
 
-import type {
-  MutableSource,
-  MutableSourceGetSnapshotFn,
-  MutableSourceSubscribeFn,
-  ReactContext,
-  ReactProviderType,
-} from 'shared/ReactTypes';
+import type {ReactContext, ReactProviderType} from 'shared/ReactTypes';
 import type {
   Fiber,
   Dispatcher as DispatcherType,
@@ -261,23 +255,6 @@ function useMemo<T>(
   return value;
 }
 
-function useMutableSource<Source, Snapshot>(
-  source: MutableSource<Source>,
-  getSnapshot: MutableSourceGetSnapshotFn<Source, Snapshot>,
-  subscribe: MutableSourceSubscribeFn<Source, Snapshot>,
-): Snapshot {
-  // useMutableSource() composes multiple hooks internally.
-  // Advance the current hook index the same number of times
-  // so that subsequent hooks have the right memoized state.
-  nextHook(); // MutableSource
-  nextHook(); // State
-  nextHook(); // Effect
-  nextHook(); // Effect
-  const value = getSnapshot(source._source);
-  hookLog.push({primitive: 'MutableSource', stackError: new Error(), value});
-  return value;
-}
-
 function useSyncExternalStore<T>(
   subscribe: (() => void) => () => void,
   getSnapshot: () => T,
@@ -357,7 +334,6 @@ const Dispatcher: DispatcherType = {
   useRef,
   useState,
   useTransition,
-  useMutableSource,
   useSyncExternalStore,
   useDeferredValue,
   useOpaqueIdentifier,

packages/react-debug-tools/src/__tests__/ReactHooksInspectionIntegration-test.js

@@ -1019,43 +1019,6 @@ describe('ReactHooksInspectionIntegration', () => {
     ]);
   });
 
-  it('should support composite useMutableSource hook', () => {
-    const createMutableSource =
-      React.createMutableSource || React.unstable_createMutableSource;
-    const useMutableSource =
-      React.useMutableSource || React.unstable_useMutableSource;
-
-    const mutableSource = createMutableSource({}, () => 1);
-    function Foo(props) {
-      useMutableSource(
-        mutableSource,
-        () => 'snapshot',
-        () => {},
-      );
-      React.useMemo(() => 'memo', []);
-      return <div />;
-    }
-    const renderer = ReactTestRenderer.create(<Foo />);
-    const childFiber = renderer.root.findByType(Foo)._currentFiber();
-    const tree = ReactDebugTools.inspectHooksOfFiber(childFiber);
-    expect(tree).toEqual([
-      {
-        id: 0,
-        isStateEditable: false,
-        name: 'MutableSource',
-        value: 'snapshot',
-        subHooks: [],
-      },
-      {
-        id: 1,
-        isStateEditable: false,
-        name: 'Memo',
-        value: 'memo',
-        subHooks: [],
-      },
-    ]);
-  });
-
   // @gate experimental || www
   it('should support composite useSyncExternalStore hook', () => {
     const useSyncExternalStore = React.unstable_useSyncExternalStore;

packages/react-dom/src/client/ReactDOMRoot.js

@@ -8,7 +8,7 @@
  */
 
 import type {Container} from './ReactDOMHostConfig';
-import type {MutableSource, ReactNodeList} from 'shared/ReactTypes';
+import type {ReactNodeList} from 'shared/ReactTypes';
 import type {FiberRoot} from 'react-reconciler/src/ReactInternalTypes';
 
 export type RootType = {
@@ -24,7 +24,6 @@ export type CreateRootOptions = {
   hydrationOptions?: {
     onHydrated?: (suspenseNode: Comment) => void,
     onDeleted?: (suspenseNode: Comment) => void,
-    mutableSources?: Array<MutableSource<any>>,
     ...
   },
   // END OF TODO
@@ -35,7 +34,6 @@ export type CreateRootOptions = {
 
 export type HydrateRootOptions = {
   // Hydration options
-  hydratedSources?: Array<MutableSource<any>>,
   onHydrated?: (suspenseNode: Comment) => void,
   onDeleted?: (suspenseNode: Comment) => void,
   // Options for all roots
@@ -61,7 +59,6 @@ import {
   createContainer,
   updateContainer,
   findHostInstanceWithNoPortals,
-  registerMutableSourceForHydration,
 } from 'react-reconciler/src/ReactFiberReconciler';
 import invariant from 'shared/invariant';
 import {ConcurrentRoot} from 'react-reconciler/src/ReactRootTags';
@@ -129,11 +126,6 @@ export function createRoot(
   const hydrate = options != null && options.hydrate === true;
   const hydrationCallbacks =
     (options != null && options.hydrationOptions) || null;
-  const mutableSources =
-    (options != null &&
-      options.hydrationOptions != null &&
-      options.hydrationOptions.mutableSources) ||
-    null;
   // END TODO
 
   const isStrictMode = options != null && options.unstable_strictMode === true;
@@ -159,15 +151,6 @@ export function createRoot(
     container.nodeType === COMMENT_NODE ? container.parentNode : container;
   listenToAllSupportedEvents(rootContainerElement);
 
-  // TODO: Delete this path
-  if (mutableSources) {
-    for (let i = 0; i < mutableSources.length; i++) {
-      const mutableSource = mutableSources[i];
-      registerMutableSourceForHydration(root, mutableSource);
-    }
-  }
-  // END TODO
-
   return new ReactDOMRoot(root);
 }
 
@@ -185,7 +168,6 @@ export function hydrateRoot(
   // For now we reuse the whole bag of options since they contain
   // the hydration callbacks.
   const hydrationCallbacks = options != null ? options : null;
-  const mutableSources = (options != null && options.hydratedSources) || null;
   const isStrictMode = options != null && options.unstable_strictMode === true;
 
   let concurrentUpdatesByDefaultOverride = null;
@@ -208,13 +190,6 @@ export function hydrateRoot(
   // This can't be a comment node since hydration doesn't work on comment nodes anyway.
   listenToAllSupportedEvents(container);
 
-  if (mutableSources) {
-    for (let i = 0; i < mutableSources.length; i++) {
-      const mutableSource = mutableSources[i];
-      registerMutableSourceForHydration(root, mutableSource);
-    }
-  }
-
   // Render the initial children
   updateContainer(initialChildren, root, null, null);
 

packages/react-dom/src/server/ReactPartialRendererHooks.js

@@ -9,12 +9,7 @@
 
 import type {Dispatcher as DispatcherType} from 'react-reconciler/src/ReactInternalTypes';
 
-import type {
-  MutableSource,
-  MutableSourceGetSnapshotFn,
-  MutableSourceSubscribeFn,
-  ReactContext,
-} from 'shared/ReactTypes';
+import type {ReactContext} from 'shared/ReactTypes';
 import type PartialRenderer from './ReactPartialRenderer';
 
 import {validateContextBounds} from './ReactPartialRendererContext';
@@ -466,18 +461,6 @@ export function useCallback<T>(
   return useMemo(() => callback, deps);
 }
 
-// TODO Decide on how to implement this hook for server rendering.
-// If a mutation occurs during render, consider triggering a Suspense boundary
-// and falling back to client rendering.
-function useMutableSource<Source, Snapshot>(
-  source: MutableSource<Source>,
-  getSnapshot: MutableSourceGetSnapshotFn<Source, Snapshot>,
-  subscribe: MutableSourceSubscribeFn<Source, Snapshot>,
-): Snapshot {
-  resolveCurrentlyRenderingComponent();
-  return getSnapshot(source._source);
-}
-
 function useSyncExternalStore<T>(
   subscribe: (() => void) => () => void,
   getSnapshot: () => T,
@@ -536,8 +519,6 @@ export const Dispatcher: DispatcherType = {
   useDeferredValue,
   useTransition,
   useOpaqueIdentifier,
-  // Subscriptions are not setup in a server environment.
-  useMutableSource,
   useSyncExternalStore,
 };
 

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

@@ -12,7 +12,6 @@ import type {LazyComponent as LazyComponentType} from 'react/src/ReactLazy';
 import type {Fiber, FiberRoot} from './ReactInternalTypes';
 import type {TypeOfMode} from './ReactTypeOfMode';
 import type {Lanes, Lane} from './ReactFiberLane.new';
-import type {MutableSource} from 'shared/ReactTypes';
 import type {
   SuspenseState,
   SuspenseListRenderState,
@@ -145,7 +144,6 @@ import {
   isSuspenseInstancePending,
   isSuspenseInstanceFallback,
   registerSuspenseInstanceRetry,
-  supportsHydration,
   isPrimaryRenderer,
   supportsPersistence,
   getOffscreenContainerProps,
@@ -224,7 +222,6 @@ import {
   RetryAfterError,
   NoContext,
 } from './ReactFiberWorkLoop.new';
-import {setWorkInProgressVersion} from './ReactMutableSource.new';
 import {
   requestCacheFromPool,
   pushCacheProvider,
@@ -1303,21 +1300,6 @@ function updateHostRoot(current, workInProgress, renderLanes) {
     // We always try to hydrate. If this isn't a hydration pass there won't
     // be any children to hydrate which is effectively the same thing as
     // not hydrating.
-
-    if (supportsHydration) {
-      const mutableSourceEagerHydrationData =
-        root.mutableSourceEagerHydrationData;
-      if (mutableSourceEagerHydrationData != null) {
-        for (let i = 0; i < mutableSourceEagerHydrationData.length; i += 2) {
-          const mutableSource = ((mutableSourceEagerHydrationData[
-            i
-          ]: any): MutableSource<any>);
-          const version = mutableSourceEagerHydrationData[i + 1];
-          setWorkInProgressVersion(mutableSource, version);
-        }
-      }
-    }
-
     const child = mountChildFibers(
       workInProgress,
       null,

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

@@ -12,7 +12,6 @@ import type {LazyComponent as LazyComponentType} from 'react/src/ReactLazy';
 import type {Fiber, FiberRoot} from './ReactInternalTypes';
 import type {TypeOfMode} from './ReactTypeOfMode';
 import type {Lanes, Lane} from './ReactFiberLane.old';
-import type {MutableSource} from 'shared/ReactTypes';
 import type {
   SuspenseState,
   SuspenseListRenderState,
@@ -145,7 +144,6 @@ import {
   isSuspenseInstancePending,
   isSuspenseInstanceFallback,
   registerSuspenseInstanceRetry,
-  supportsHydration,
   isPrimaryRenderer,
   supportsPersistence,
   getOffscreenContainerProps,
@@ -224,7 +222,6 @@ import {
   RetryAfterError,
   NoContext,
 } from './ReactFiberWorkLoop.old';
-import {setWorkInProgressVersion} from './ReactMutableSource.old';
 import {
   requestCacheFromPool,
   pushCacheProvider,
@@ -1303,21 +1300,6 @@ function updateHostRoot(current, workInProgress, renderLanes) {
     // We always try to hydrate. If this isn't a hydration pass there won't
     // be any children to hydrate which is effectively the same thing as
     // not hydrating.
-
-    if (supportsHydration) {
-      const mutableSourceEagerHydrationData =
-        root.mutableSourceEagerHydrationData;
-      if (mutableSourceEagerHydrationData != null) {
-        for (let i = 0; i < mutableSourceEagerHydrationData.length; i += 2) {
-          const mutableSource = ((mutableSourceEagerHydrationData[
-            i
-          ]: any): MutableSource<any>);
-          const version = mutableSourceEagerHydrationData[i + 1];
-          setWorkInProgressVersion(mutableSource, version);
-        }
-      }
-    }
-
     const child = mountChildFibers(
       workInProgress,
       null,

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

@@ -30,8 +30,6 @@ import type {SuspenseContext} from './ReactFiberSuspenseContext.new';
 import type {OffscreenState} from './ReactFiberOffscreenComponent';
 import type {Cache, SpawnedCachePool} from './ReactFiberCacheComponent.new';
 
-import {resetWorkInProgressVersions as resetMutableSourceWorkInProgressVersions} from './ReactMutableSource.new';
-
 import {now} from './Scheduler';
 
 import {
@@ -854,7 +852,6 @@ function completeWork(
       }
       popHostContainer(workInProgress);
       popTopLevelLegacyContextObject(workInProgress);
-      resetMutableSourceWorkInProgressVersions();
       if (fiberRoot.pendingContext) {
         fiberRoot.context = fiberRoot.pendingContext;
         fiberRoot.pendingContext = null;

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

@@ -30,8 +30,6 @@ import type {SuspenseContext} from './ReactFiberSuspenseContext.old';
 import type {OffscreenState} from './ReactFiberOffscreenComponent';
 import type {Cache, SpawnedCachePool} from './ReactFiberCacheComponent.old';
 
-import {resetWorkInProgressVersions as resetMutableSourceWorkInProgressVersions} from './ReactMutableSource.old';
-
 import {now} from './Scheduler';
 
 import {
@@ -854,7 +852,6 @@ function completeWork(
       }
       popHostContainer(workInProgress);
       popTopLevelLegacyContextObject(workInProgress);
-      resetMutableSourceWorkInProgressVersions();
       if (fiberRoot.pendingContext) {
         fiberRoot.context = fiberRoot.pendingContext;
         fiberRoot.pendingContext = null;

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

@@ -283,9 +283,9 @@ export function getNextLanes(root: FiberRoot, wipLanes: Lanes): Lanes {
   // time it takes to show the final state, which is what they are actually
   // waiting for.
   //
-  // For those exceptions where entanglement is semantically important, like
-  // useMutableSource, we should ensure that there is no partial work at the
-  // time we apply the entanglement.
+  // For those exceptions where entanglement is semantically important, we
+  // should ensure that there is no partial work at the time we apply the
+  // entanglement.
   const entangledLanes = root.entangledLanes;
   if (entangledLanes !== NoLanes) {
     const entanglements = root.entanglements;
@@ -617,10 +617,6 @@ export function markRootPinged(
   root.pingedLanes |= root.suspendedLanes & pingedLanes;
 }
 
-export function markRootMutableRead(root: FiberRoot, updateLane: Lane) {
-  root.mutableReadLanes |= updateLane & root.pendingLanes;
-}
-
 export function markRootFinished(root: FiberRoot, remainingLanes: Lanes) {
   const noLongerPendingLanes = root.pendingLanes & ~remainingLanes;
 
@@ -631,7 +627,6 @@ export function markRootFinished(root: FiberRoot, remainingLanes: Lanes) {
   root.pingedLanes = 0;
 
   root.expiredLanes &= remainingLanes;
-  root.mutableReadLanes &= remainingLanes;
 
   root.entangledLanes &= remainingLanes;
 

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

@@ -283,9 +283,9 @@ export function getNextLanes(root: FiberRoot, wipLanes: Lanes): Lanes {
   // time it takes to show the final state, which is what they are actually
   // waiting for.
   //
-  // For those exceptions where entanglement is semantically important, like
-  // useMutableSource, we should ensure that there is no partial work at the
-  // time we apply the entanglement.
+  // For those exceptions where entanglement is semantically important, we
+  // should ensure that there is no partial work at the time we apply the
+  // entanglement.
   const entangledLanes = root.entangledLanes;
   if (entangledLanes !== NoLanes) {
     const entanglements = root.entanglements;
@@ -617,10 +617,6 @@ export function markRootPinged(
   root.pingedLanes |= root.suspendedLanes & pingedLanes;
 }
 
-export function markRootMutableRead(root: FiberRoot, updateLane: Lane) {
-  root.mutableReadLanes |= updateLane & root.pendingLanes;
-}
-
 export function markRootFinished(root: FiberRoot, remainingLanes: Lanes) {
   const noLongerPendingLanes = root.pendingLanes & ~remainingLanes;
 
@@ -631,7 +627,6 @@ export function markRootFinished(root: FiberRoot, remainingLanes: Lanes) {
   root.pingedLanes = 0;
 
   root.expiredLanes &= remainingLanes;
-  root.mutableReadLanes &= remainingLanes;
 
   root.entangledLanes &= remainingLanes;
 

packages/react-reconciler/src/ReactFiberReconciler.js

@@ -46,7 +46,6 @@ import {
   findBoundingRects as findBoundingRects_old,
   focusWithin as focusWithin_old,
   observeVisibleRects as observeVisibleRects_old,
-  registerMutableSourceForHydration as registerMutableSourceForHydration_old,
   runWithPriority as runWithPriority_old,
   getCurrentUpdatePriority as getCurrentUpdatePriority_old,
   getIsStrictModeForDevtools as getIsStrictModeForDevtools_old,
@@ -85,7 +84,6 @@ import {
   findBoundingRects as findBoundingRects_new,
   focusWithin as focusWithin_new,
   observeVisibleRects as observeVisibleRects_new,
-  registerMutableSourceForHydration as registerMutableSourceForHydration_new,
   runWithPriority as runWithPriority_new,
   getCurrentUpdatePriority as getCurrentUpdatePriority_new,
   getIsStrictModeForDevtools as getIsStrictModeForDevtools_new,
@@ -188,9 +186,6 @@ export const focusWithin = enableNewReconciler
 export const observeVisibleRects = enableNewReconciler
   ? observeVisibleRects_new
   : observeVisibleRects_old;
-export const registerMutableSourceForHydration = enableNewReconciler
-  ? registerMutableSourceForHydration_new
-  : registerMutableSourceForHydration_old;
 export const runWithPriority = enableNewReconciler
   ? runWithPriority_new
   : runWithPriority_old;

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

@@ -93,7 +93,6 @@ import {
 } from './ReactFiberHotReloading.new';
 import {markRenderScheduled} from './SchedulingProfiler';
 import ReactVersion from 'shared/ReactVersion';
-export {registerMutableSourceForHydration} from './ReactMutableSource.new';
 export {createPortal} from './ReactPortal';
 export {
   createComponentSelector,

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

@@ -93,7 +93,6 @@ import {
 } from './ReactFiberHotReloading.old';
 import {markRenderScheduled} from './SchedulingProfiler';
 import ReactVersion from 'shared/ReactVersion';
-export {registerMutableSourceForHydration} from './ReactMutableSource.old';
 export {createPortal} from './ReactPortal';
 export {
   createComponentSelector,

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

@@ -49,7 +49,6 @@ function FiberRootNode(containerInfo, tag, hydrate) {
   this.suspendedLanes = NoLanes;
   this.pingedLanes = NoLanes;
   this.expiredLanes = NoLanes;
-  this.mutableReadLanes = NoLanes;
   this.finishedLanes = NoLanes;
 
   this.entangledLanes = NoLanes;

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

@@ -49,7 +49,6 @@ function FiberRootNode(containerInfo, tag, hydrate) {
   this.suspendedLanes = NoLanes;
   this.pingedLanes = NoLanes;
   this.expiredLanes = NoLanes;
-  this.mutableReadLanes = NoLanes;
   this.finishedLanes = NoLanes;
 
   this.entangledLanes = NoLanes;

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

@@ -13,7 +13,6 @@ import type {Lanes} from './ReactFiberLane.new';
 import type {SuspenseState} from './ReactFiberSuspenseComponent.new';
 import type {Cache, SpawnedCachePool} from './ReactFiberCacheComponent.new';
 
-import {resetWorkInProgressVersions as resetMutableSourceWorkInProgressVersions} from './ReactMutableSource.new';
 import {
   ClassComponent,
   HostRoot,
@@ -83,7 +82,6 @@ function unwindWork(workInProgress: Fiber, renderLanes: Lanes) {
       }
       popHostContainer(workInProgress);
       popTopLevelLegacyContextObject(workInProgress);
-      resetMutableSourceWorkInProgressVersions();
       const flags = workInProgress.flags;
       invariant(
         (flags & DidCapture) === NoFlags,
@@ -179,7 +177,6 @@ function unwindInterruptedWork(interruptedWork: Fiber, renderLanes: Lanes) {
       }
       popHostContainer(interruptedWork);
       popTopLevelLegacyContextObject(interruptedWork);
-      resetMutableSourceWorkInProgressVersions();
       break;
     }
     case HostComponent: {

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

@@ -13,7 +13,6 @@ import type {Lanes} from './ReactFiberLane.old';
 import type {SuspenseState} from './ReactFiberSuspenseComponent.old';
 import type {Cache, SpawnedCachePool} from './ReactFiberCacheComponent.old';
 
-import {resetWorkInProgressVersions as resetMutableSourceWorkInProgressVersions} from './ReactMutableSource.old';
 import {
   ClassComponent,
   HostRoot,
@@ -83,7 +82,6 @@ function unwindWork(workInProgress: Fiber, renderLanes: Lanes) {
       }
       popHostContainer(workInProgress);
       popTopLevelLegacyContextObject(workInProgress);
-      resetMutableSourceWorkInProgressVersions();
       const flags = workInProgress.flags;
       invariant(
         (flags & DidCapture) === NoFlags,
@@ -179,7 +177,6 @@ function unwindInterruptedWork(interruptedWork: Fiber, renderLanes: Lanes) {
       }
       popHostContainer(interruptedWork);
       popTopLevelLegacyContextObject(interruptedWork);
-      resetMutableSourceWorkInProgressVersions();
       break;
     }
     case HostComponent: {

packages/react-reconciler/src/ReactInternalTypes.js

@@ -8,14 +8,7 @@
  */
 
 import type {Source} from 'shared/ReactElementType';
-import type {
-  RefObject,
-  ReactContext,
-  MutableSourceSubscribeFn,
-  MutableSourceGetSnapshotFn,
-  MutableSourceVersion,
-  MutableSource,
-} from 'shared/ReactTypes';
+import type {RefObject, ReactContext} from 'shared/ReactTypes';
 import type {SuspenseInstance} from './ReactFiberHostConfig';
 import type {WorkTag} from './ReactWorkTags';
 import type {TypeOfMode} from './ReactTypeOfMode';
@@ -41,7 +34,6 @@ export type HookType =
   | 'useDebugValue'
   | 'useDeferredValue'
   | 'useTransition'
-  | 'useMutableSource'
   | 'useSyncExternalStore'
   | 'useOpaqueIdentifier'
   | 'useCacheRefresh';
@@ -214,11 +206,6 @@ type BaseFiberRootProperties = {|
   // Determines if we should attempt to hydrate on the initial mount
   +hydrate: boolean,
 
-  // Used by useMutableSource hook to avoid tearing during hydration.
-  mutableSourceEagerHydrationData?: Array<
-    MutableSource<any> | MutableSourceVersion,
-  > | null,
-
   // Node returned by Scheduler.scheduleCallback. Represents the next rendering
   // task that the root will work on.
   callbackNode: *,
@@ -230,7 +217,6 @@ type BaseFiberRootProperties = {|
   suspendedLanes: Lanes,
   pingedLanes: Lanes,
   expiredLanes: Lanes,
-  mutableReadLanes: Lanes,
 
   finishedLanes: Lanes,
 
@@ -305,11 +291,6 @@ export type Dispatcher = {|
   useDebugValue<T>(value: T, formatterFn: ?(value: T) => mixed): void,
   useDeferredValue<T>(value: T): T,
   useTransition(): [boolean, (() => void) => void],
-  useMutableSource<Source, Snapshot>(
-    source: MutableSource<Source>,
-    getSnapshot: MutableSourceGetSnapshotFn<Source, Snapshot>,
-    subscribe: MutableSourceSubscribeFn<Source, Snapshot>,
-  ): Snapshot,
   useSyncExternalStore<T>(
     subscribe: (() => void) => () => void,
     getSnapshot: () => T,

packages/react-server/src/ReactFizzHooks.js

@@ -9,12 +9,7 @@
 
 import type {Dispatcher as DispatcherType} from 'react-reconciler/src/ReactInternalTypes';
 
-import type {
-  MutableSource,
-  MutableSourceGetSnapshotFn,
-  MutableSourceSubscribeFn,
-  ReactContext,
-} from 'shared/ReactTypes';
+import type {ReactContext} from 'shared/ReactTypes';
 
 import type {ResponseState, OpaqueIDType} from './ReactServerFormatConfig';
 
@@ -449,18 +444,6 @@ export function useCallback<T>(
   return useMemo(() => callback, deps);
 }
 
-// TODO Decide on how to implement this hook for server rendering.
-// If a mutation occurs during render, consider triggering a Suspense boundary
-// and falling back to client rendering.
-function useMutableSource<Source, Snapshot>(
-  source: MutableSource<Source>,
-  getSnapshot: MutableSourceGetSnapshotFn<Source, Snapshot>,
-  subscribe: MutableSourceSubscribeFn<Source, Snapshot>,
-): Snapshot {
-  resolveCurrentlyRenderingComponent();
-  return getSnapshot(source._source);
-}
-
 function useSyncExternalStore<T>(
   subscribe: (() => void) => () => void,
   getSnapshot: () => T,
@@ -515,8 +498,6 @@ export const Dispatcher: DispatcherType = {
   useDeferredValue,
   useTransition,
   useOpaqueIdentifier,
-  // Subscriptions are not setup in a server environment.
-  useMutableSource,
   useSyncExternalStore,
 };
 

packages/react-server/src/ReactFlightServer.js

@@ -827,7 +827,6 @@ const Dispatcher: DispatcherType = {
   useImperativeHandle: (unsupportedHook: any),
   useEffect: (unsupportedHook: any),
   useOpaqueIdentifier: (unsupportedHook: any),
-  useMutableSource: (unsupportedHook: any),
   useSyncExternalStore: (unsupportedHook: any),
   useCacheRefresh(): <T>(?() => T, ?T) => void {
     return unsupportedRefresh;

packages/react-suspense-test-utils/src/ReactSuspenseTestUtils.js

@@ -44,7 +44,6 @@ export function waitForSuspense<T>(fn: () => T): Promise<T> {
     useDeferredValue: unsupported,
     useTransition: unsupported,
     useOpaqueIdentifier: unsupported,
-    useMutableSource: unsupported,
     useSyncExternalStore: unsupported,
     useCacheRefresh: unsupported,
   };

packages/react/index.classic.fb.js

@@ -23,8 +23,6 @@ export {
   createContext,
   createElement,
   createFactory,
-  createMutableSource,
-  createMutableSource as unstable_createMutableSource,
   createRef,
   forwardRef,
   isValidElement,
@@ -50,8 +48,6 @@ export {
   useLayoutEffect,
   unstable_useInsertionEffect,
   useMemo,
-  useMutableSource,
-  useMutableSource as unstable_useMutableSource,
   useSyncExternalStore,
   useSyncExternalStore as unstable_useSyncExternalStore,
   useReducer,

packages/react/index.experimental.js

@@ -22,7 +22,6 @@ export {
   createContext,
   createElement,
   createFactory,
-  createMutableSource as unstable_createMutableSource,
   createRef,
   forwardRef,
   isValidElement,
@@ -45,7 +44,6 @@ export {
   unstable_useInsertionEffect,
   useLayoutEffect,
   useMemo,
-  useMutableSource as unstable_useMutableSource,
   useSyncExternalStore as unstable_useSyncExternalStore,
   useReducer,
   useRef,

packages/react/index.js

@@ -46,7 +46,6 @@ export {
   createContext,
   createElement,
   createFactory,
-  createMutableSource,
   createRef,
   forwardRef,
   isValidElement,
@@ -70,7 +69,6 @@ export {
   unstable_useInsertionEffect,
   useLayoutEffect,
   useMemo,
-  useMutableSource,
   useSyncExternalStore,
   useSyncExternalStore as unstable_useSyncExternalStore,
   useReducer,

packages/react/index.modern.fb.js

@@ -22,8 +22,6 @@ export {
   cloneElement,
   createContext,
   createElement,
-  createMutableSource,
-  createMutableSource as unstable_createMutableSource,
   createRef,
   forwardRef,
   isValidElement,
@@ -49,8 +47,6 @@ export {
   unstable_useInsertionEffect,
   useLayoutEffect,
   useMemo,
-  useMutableSource,
-  useMutableSource as unstable_useMutableSource,
   useSyncExternalStore,
   useSyncExternalStore as unstable_useSyncExternalStore,
   useReducer,

packages/react/index.stable.js

@@ -22,7 +22,6 @@ export {
   createContext,
   createElement,
   createFactory,
-  createMutableSource as unstable_createMutableSource,
   createRef,
   forwardRef,
   isValidElement,
@@ -38,7 +37,6 @@ export {
   useImperativeHandle,
   useLayoutEffect,
   useMemo,
-  useMutableSource as unstable_useMutableSource,
   useReducer,
   useRef,
   useState,

packages/react/src/React.js

@@ -44,7 +44,6 @@ import {
   useInsertionEffect,
   useLayoutEffect,
   useMemo,
-  useMutableSource,
   useSyncExternalStore,
   useReducer,
   useRef,
@@ -59,7 +58,6 @@ import {
   createFactoryWithValidation,
   cloneElementWithValidation,
 } from './ReactElementValidator';
-import {createMutableSource} from './ReactMutableSource';
 import ReactSharedInternals from './ReactSharedInternals';
 import {startTransition} from './ReactStartTransition';
 import {act} from './ReactAct';
@@ -79,7 +77,6 @@ const Children = {
 
 export {
   Children,
-  createMutableSource,
   createRef,
   Component,
   PureComponent,
@@ -95,7 +92,6 @@ export {
   useInsertionEffect as unstable_useInsertionEffect,
   useLayoutEffect,
   useMemo,
-  useMutableSource,
   useSyncExternalStore,
   useReducer,
   useRef,

packages/react/src/ReactHooks.js

@@ -8,12 +8,7 @@
  */
 
 import type {Dispatcher} from 'react-reconciler/src/ReactInternalTypes';
-import type {
-  MutableSource,
-  MutableSourceGetSnapshotFn,
-  MutableSourceSubscribeFn,
-  ReactContext,
-} from 'shared/ReactTypes';
+import type {ReactContext} from 'shared/ReactTypes';
 import type {OpaqueIDType} from 'react-reconciler/src/ReactFiberHostConfig';
 
 import ReactCurrentDispatcher from './ReactCurrentDispatcher';
@@ -168,15 +163,6 @@ export function useOpaqueIdentifier(): OpaqueIDType | void {
   return dispatcher.useOpaqueIdentifier();
 }
 
-export function useMutableSource<Source, Snapshot>(
-  source: MutableSource<Source>,
-  getSnapshot: MutableSourceGetSnapshotFn<Source, Snapshot>,
-  subscribe: MutableSourceSubscribeFn<Source, Snapshot>,
-): Snapshot {
-  const dispatcher = resolveDispatcher();
-  return dispatcher.useMutableSource(source, getSnapshot, subscribe);
-}
-
 export function useSyncExternalStore<T>(
   subscribe: (() => void) => () => void,
   getSnapshot: () => T,

packages/react/unstable-shared-subset.experimental.js

@@ -17,7 +17,6 @@ export {
   SuspenseList,
   cloneElement,
   createElement,
-  createMutableSource as unstable_createMutableSource,
   createRef,
   forwardRef,
   isValidElement,
@@ -33,7 +32,6 @@ export {
   useDeferredValue,
   useDeferredValue as unstable_useDeferredValue,
   useMemo,
-  useMutableSource as unstable_useMutableSource,
   useTransition,
   version,
 } from './src/React';

packages/shared/ReactTypes.js

@@ -101,56 +101,6 @@ export type ReactScopeInstance = {|
   getChildContextValues: <T>(context: ReactContext<T>) => Array<T>,
 |};
 
-// Mutable source version can be anything (e.g. number, string, immutable data structure)
-// so long as it changes every time any part of the source changes.
-export type MutableSourceVersion = $NonMaybeType<mixed>;
-
-export type MutableSourceGetSnapshotFn<
-  Source: $NonMaybeType<mixed>,
-  Snapshot,
-> = (source: Source) => Snapshot;
-
-export type MutableSourceSubscribeFn<Source: $NonMaybeType<mixed>, Snapshot> = (
-  source: Source,
-  callback: (snapshot: Snapshot) => void,
-) => () => void;
-
-export type MutableSourceGetVersionFn = (
-  source: $NonMaybeType<mixed>,
-) => MutableSourceVersion;
-
-export type MutableSource<Source: $NonMaybeType<mixed>> = {|
-  _source: Source,
-
-  _getVersion: MutableSourceGetVersionFn,
-
-  // Tracks the version of this source at the time it was most recently read.
-  // Used to determine if a source is safe to read from before it has been subscribed to.
-  // Version number is only used during mount,
-  // since the mechanism for determining safety after subscription is expiration time.
-  //
-  // As a workaround to support multiple concurrent renderers,
-  // we categorize some renderers as primary and others as secondary.
-  // We only expect there to be two concurrent renderers at most:
-  // React Native (primary) and Fabric (secondary);
-  // React DOM (primary) and React ART (secondary).
-  // Secondary renderers store their context values on separate fields.
-  // We use the same approach for Context.
-  _workInProgressVersionPrimary: null | MutableSourceVersion,
-  _workInProgressVersionSecondary: null | MutableSourceVersion,
-
-  // DEV only
-  // Used to detect multiple renderers using the same mutable source.
-  _currentPrimaryRenderer?: Object | null,
-  _currentSecondaryRenderer?: Object | null,
-
-  // DEV only
-  // Used to detect side effects that update a mutable source during render.
-  // See https://github.com/facebook/react/issues/19948
-  _currentlyRenderingFiber?: Fiber | null,
-  _initialVersionAsOfFirstRender?: MutableSourceVersion | null,
-|};
-
 // The subset of a Thenable required by things thrown by Suspense.
 // This doesn't require a value to be passed to either handler.
 export interface Wakeable {