Remove useHooks feature flag entirely

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

@@ -21,7 +21,6 @@ import describeComponentFrame from 'shared/describeComponentFrame';
 import ReactSharedInternals from 'shared/ReactSharedInternals';
 import {
   warnAboutDeprecatedLifecycles,
-  enableHooks,
   enableSuspenseServerRenderer,
 } from 'shared/ReactFeatureFlags';
 
@@ -55,7 +54,6 @@ import {
   prepareToUseHooks,
   finishHooks,
   Dispatcher,
-  DispatcherWithoutHooks,
   currentThreadID,
   setCurrentThreadID,
 } from './ReactPartialRendererHooks';
@@ -786,11 +784,7 @@ class ReactDOMServerRenderer {
     const prevThreadID = currentThreadID;
     setCurrentThreadID(this.threadID);
     const prevDispatcher = ReactCurrentDispatcher.current;
-    if (enableHooks) {
-      ReactCurrentDispatcher.current = Dispatcher;
-    } else {
-      ReactCurrentDispatcher.current = DispatcherWithoutHooks;
-    }
+    ReactCurrentDispatcher.current = Dispatcher;
     try {
       // Markup generated within <Suspense> ends up buffered until we know
       // nothing in that boundary suspended

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

@@ -423,6 +423,3 @@ export const Dispatcher: DispatcherType = {
   // Debugging effect
   useDebugValue: noop,
 };
-export const DispatcherWithoutHooks = {
-  readContext,
-};

packages/react-reconciler/src/ReactFiberCommitWork.js

@@ -24,7 +24,6 @@ import type {Thenable} from './ReactFiberScheduler';
 
 import {unstable_wrap as Schedule_tracing_wrap} from 'scheduler/tracing';
 import {
-  enableHooks,
   enableSchedulerTracing,
   enableProfilerTimer,
 } from 'shared/ReactFeatureFlags';
@@ -312,9 +311,6 @@ function commitHookEffectList(
   mountTag: number,
   finishedWork: Fiber,
 ) {
-  if (!enableHooks) {
-    return;
-  }
   const updateQueue: FunctionComponentUpdateQueue | null = (finishedWork.updateQueue: any);
   let lastEffect = updateQueue !== null ? updateQueue.lastEffect : null;
   if (lastEffect !== null) {

packages/react-reconciler/src/ReactFiberDispatcher.js

@@ -34,6 +34,3 @@ export const Dispatcher = {
   useRef,
   useState,
 };
-export const DispatcherWithoutHooks = {
-  readContext,
-};

packages/react-reconciler/src/ReactFiberHooks.js

@@ -13,7 +13,6 @@ import type {ExpirationTime} from './ReactFiberExpirationTime';
 import type {HookEffectTag} from './ReactHookEffectTags';
 
 import {NoWork} from './ReactFiberExpirationTime';
-import {enableHooks} from 'shared/ReactFeatureFlags';
 import {
   readContext,
   stashContextDependencies,
@@ -296,9 +295,6 @@ export function renderWithHooks(
   refOrContext: any,
   nextRenderExpirationTime: ExpirationTime,
 ): any {
-  if (!enableHooks) {
-    return Component(props, refOrContext);
-  }
   renderExpirationTime = nextRenderExpirationTime;
   currentlyRenderingFiber = workInProgress;
   firstCurrentHook = current !== null ? current.memoizedState : null;
@@ -397,9 +393,6 @@ export function bailoutHooks(
 }
 
 export function resetHooks(): void {
-  if (!enableHooks) {
-    return;
-  }
   if (__DEV__) {
     flushHookMismatchWarnings();
   }

packages/react-reconciler/src/ReactFiberScheduler.js

@@ -56,7 +56,6 @@ import {
   SimpleMemoComponent,
 } from 'shared/ReactWorkTags';
 import {
-  enableHooks,
   enableSchedulerTracing,
   enableProfilerTimer,
   enableUserTimingAPI,
@@ -165,7 +164,7 @@ import {
   commitDetachRef,
   commitPassiveHookEffects,
 } from './ReactFiberCommitWork';
-import {Dispatcher, DispatcherWithoutHooks} from './ReactFiberDispatcher';
+import {Dispatcher} from './ReactFiberDispatcher';
 
 export type Thenable = {
   then(resolve: () => mixed, reject?: () => mixed): mixed,
@@ -510,7 +509,7 @@ function commitAllLifeCycles(
       commitAttachRef(nextEffect);
     }
 
-    if (enableHooks && effectTag & Passive) {
+    if (effectTag & Passive) {
       rootWithPendingPassiveEffects = finishedRoot;
     }
 
@@ -784,11 +783,7 @@ function commitRoot(root: FiberRoot, finishedWork: Fiber): void {
     }
   }
 
-  if (
-    enableHooks &&
-    firstEffect !== null &&
-    rootWithPendingPassiveEffects !== null
-  ) {
+  if (firstEffect !== null && rootWithPendingPassiveEffects !== null) {
     // This commit included a passive effect. These do not need to fire until
     // after the next paint. Schedule an callback to fire them in an async
     // event. To ensure serial execution, the callback will be flushed early if
@@ -1221,11 +1216,7 @@ function renderRoot(root: FiberRoot, isYieldy: boolean): void {
   flushPassiveEffects();
 
   isWorking = true;
-  if (enableHooks) {
-    ReactCurrentDispatcher.current = Dispatcher;
-  } else {
-    ReactCurrentDispatcher.current = DispatcherWithoutHooks;
-  }
+  ReactCurrentDispatcher.current = Dispatcher;
 
   const expirationTime = root.nextExpirationTimeToWorkOn;
 

packages/react-test-renderer/src/ReactShallowRenderer.js

@@ -15,7 +15,6 @@ import shallowEqual from 'shared/shallowEqual';
 import invariant from 'shared/invariant';
 import checkPropTypes from 'prop-types/checkPropTypes';
 import ReactSharedInternals from 'shared/ReactSharedInternals';
-import {enableHooks} from 'shared/ReactFeatureFlags';
 import warning from 'shared/warning';
 import is from 'shared/objectIs';
 
@@ -187,17 +186,15 @@ class ReactShallowRenderer {
     this._rendering = false;
     this._forcedUpdate = false;
     this._updater = new Updater(this);
-    if (enableHooks) {
-      this._dispatcher = this._createDispatcher();
-      this._workInProgressHook = null;
-      this._firstWorkInProgressHook = null;
-      this._isReRender = false;
-      this._didScheduleRenderPhaseUpdate = false;
-      this._renderPhaseUpdates = null;
-      this._currentlyRenderingComponent = null;
-      this._numberOfReRenders = 0;
-      this._previousComponentIdentity = null;
-    }
+    this._dispatcher = this._createDispatcher();
+    this._workInProgressHook = null;
+    this._firstWorkInProgressHook = null;
+    this._isReRender = false;
+    this._didScheduleRenderPhaseUpdate = false;
+    this._renderPhaseUpdates = null;
+    this._currentlyRenderingComponent = null;
+    this._numberOfReRenders = 0;
+    this._previousComponentIdentity = null;
   }
 
   _context: null | Object;
@@ -560,27 +557,19 @@ class ReactShallowRenderer {
 
         this._mountClassComponent(element, this._context);
       } else {
-        if (enableHooks) {
-          const prevDispatcher = ReactCurrentDispatcher.current;
-          ReactCurrentDispatcher.current = this._dispatcher;
-          this._prepareToUseHooks(element.type);
-          try {
-            this._rendered = element.type.call(
-              undefined,
-              element.props,
-              this._context,
-            );
-          } finally {
-            ReactCurrentDispatcher.current = prevDispatcher;
-          }
-          this._finishHooks(element, context);
-        } else {
+        const prevDispatcher = ReactCurrentDispatcher.current;
+        ReactCurrentDispatcher.current = this._dispatcher;
+        this._prepareToUseHooks(element.type);
+        try {
           this._rendered = element.type.call(
             undefined,
             element.props,
             this._context,
           );
+        } finally {
+          ReactCurrentDispatcher.current = prevDispatcher;
         }
+        this._finishHooks(element, context);
       }
     }
 

packages/react/src/React.js

@@ -13,7 +13,6 @@ import {
   REACT_STRICT_MODE_TYPE,
   REACT_SUSPENSE_TYPE,
 } from 'shared/ReactSymbols';
-import {enableHooks} from 'shared/ReactFeatureFlags';
 
 import {Component, PureComponent} from './ReactBaseClasses';
 import {createRef} from './ReactCreateRef';
@@ -66,6 +65,17 @@ const React = {
   lazy,
   memo,
 
+  useCallback,
+  useContext,
+  useEffect,
+  useImperativeHandle,
+  useDebugValue,
+  useLayoutEffect,
+  useMemo,
+  useReducer,
+  useRef,
+  useState,
+
   Fragment: REACT_FRAGMENT_TYPE,
   StrictMode: REACT_STRICT_MODE_TYPE,
   Suspense: REACT_SUSPENSE_TYPE,
@@ -95,17 +105,4 @@ if (enableStableConcurrentModeAPIs) {
   React.unstable_Profiler = undefined;
 }
 
-if (enableHooks) {
-  React.useCallback = useCallback;
-  React.useContext = useContext;
-  React.useEffect = useEffect;
-  React.useImperativeHandle = useImperativeHandle;
-  React.useDebugValue = useDebugValue;
-  React.useLayoutEffect = useLayoutEffect;
-  React.useMemo = useMemo;
-  React.useReducer = useReducer;
-  React.useRef = useRef;
-  React.useState = useState;
-}
-
 export default React;

packages/shared/ReactFeatureFlags.js

@@ -9,7 +9,6 @@
 
 export const enableUserTimingAPI = __DEV__;
 
-export const enableHooks = true;
 // Helps identify side effects in begin-phase lifecycle hooks and setState reducers:
 export const debugRenderPhaseSideEffects = false;
 

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

@@ -16,7 +16,6 @@ import typeof * as FeatureFlagsShimType from './ReactFeatureFlags.native-fb';
 export const {debugRenderPhaseSideEffects} = require('ReactFeatureFlags');
 
 // The rest of the flags are static for better dead code elimination.
-export const enableHooks = true;
 export const enableUserTimingAPI = __DEV__;
 export const enableProfilerTimer = __PROFILE__;
 export const enableSchedulerTracing = __PROFILE__;

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

@@ -14,7 +14,6 @@ import typeof * as FeatureFlagsShimType from './ReactFeatureFlags.native-oss';
 
 export const debugRenderPhaseSideEffects = false;
 export const debugRenderPhaseSideEffectsForStrictMode = false;
-export const enableHooks = true;
 export const enableUserTimingAPI = __DEV__;
 export const replayFailedUnitOfWorkWithInvokeGuardedCallback = __DEV__;
 export const warnAboutDeprecatedLifecycles = false;

packages/shared/forks/ReactFeatureFlags.persistent.js

@@ -15,7 +15,6 @@ import typeof * as PersistentFeatureFlagsType from './ReactFeatureFlags.persiste
 export const debugRenderPhaseSideEffects = false;
 export const debugRenderPhaseSideEffectsForStrictMode = false;
 export const enableUserTimingAPI = __DEV__;
-export const enableHooks = true;
 export const warnAboutDeprecatedLifecycles = false;
 export const replayFailedUnitOfWorkWithInvokeGuardedCallback = __DEV__;
 export const enableProfilerTimer = __PROFILE__;

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

@@ -15,7 +15,6 @@ import typeof * as PersistentFeatureFlagsType from './ReactFeatureFlags.persiste
 export const debugRenderPhaseSideEffects = false;
 export const debugRenderPhaseSideEffectsForStrictMode = false;
 export const enableUserTimingAPI = __DEV__;
-export const enableHooks = true;
 export const warnAboutDeprecatedLifecycles = false;
 export const replayFailedUnitOfWorkWithInvokeGuardedCallback = false;
 export const enableProfilerTimer = false;

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

@@ -15,7 +15,6 @@ import typeof * as PersistentFeatureFlagsType from './ReactFeatureFlags.persiste
 export const debugRenderPhaseSideEffects = false;
 export const debugRenderPhaseSideEffectsForStrictMode = false;
 export const enableUserTimingAPI = __DEV__;
-export const enableHooks = true;
 export const warnAboutDeprecatedLifecycles = false;
 export const replayFailedUnitOfWorkWithInvokeGuardedCallback = false;
 export const enableProfilerTimer = false;

packages/shared/forks/ReactFeatureFlags.www.js

@@ -21,9 +21,6 @@ export const {
   warnAboutShorthandPropertyCollision,
 } = require('ReactFeatureFlags');
 
-// The rest of the flags are static for better dead code elimination.
-export const enableHooks = true;
-
 // In www, we have experimental support for gathering data
 // from User Timing API calls in production. By default, we
 // only emit performance.mark/measure calls in __DEV__. But if