[Experimental] Add back useMutationEffect

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

@@ -78,6 +78,7 @@ function getPrimitiveStackCache(): Map<string, Array<any>> {
         Dispatcher.useCacheRefresh();
       }
       Dispatcher.useLayoutEffect(() => {});
+      Dispatcher.useMutationEffect(() => {});
       Dispatcher.useEffect(() => {});
       Dispatcher.useImperativeHandle(undefined, () => null);
       Dispatcher.useDebugValue(null);
@@ -191,6 +192,18 @@ function useLayoutEffect(
   });
 }
 
+function useMutationEffect(
+  create: () => mixed,
+  inputs: Array<mixed> | void | null,
+): void {
+  nextHook();
+  hookLog.push({
+    primitive: 'MutationEffect',
+    stackError: new Error(),
+    value: create,
+  });
+}
+
 function useEffect(
   create: () => (() => void) | void,
   inputs: Array<mixed> | void | null,
@@ -320,6 +333,7 @@ const Dispatcher: DispatcherType = {
   useImperativeHandle,
   useDebugValue,
   useLayoutEffect,
+  useMutationEffect,
   useMemo,
   useReducer,
   useRef,

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

@@ -268,6 +268,183 @@ describe('ReactHooksInspectionIntegration', () => {
     ]);
   });
 
+  // @gate experimental || www
+  // @gate source // TODO: Build gets confused by the unstable prefix.
+  it('should inspect the current state of all stateful hooks, including useMutationEffect', () => {
+    const outsideRef = React.createRef();
+    function effect() {}
+    function Foo(props) {
+      const [state1, setState] = React.useState('a');
+      const [state2, dispatch] = React.useReducer((s, a) => a.value, 'b');
+      const ref = React.useRef('c');
+
+      React.unstable_useMutationEffect(effect);
+      React.useLayoutEffect(effect);
+      React.useEffect(effect);
+
+      React.useImperativeHandle(
+        outsideRef,
+        () => {
+          // Return a function so that jest treats them as non-equal.
+          return function Instance() {};
+        },
+        [],
+      );
+
+      React.useMemo(() => state1 + state2, [state1]);
+
+      function update() {
+        act(() => {
+          setState('A');
+        });
+        act(() => {
+          dispatch({value: 'B'});
+        });
+        ref.current = 'C';
+      }
+      const memoizedUpdate = React.useCallback(update, []);
+      return (
+        <div onClick={memoizedUpdate}>
+          {state1} {state2}
+        </div>
+      );
+    }
+    let renderer;
+    act(() => {
+      renderer = ReactTestRenderer.create(<Foo prop="prop" />);
+    });
+
+    let childFiber = renderer.root.findByType(Foo)._currentFiber();
+
+    const {onClick: updateStates} = renderer.root.findByType('div').props;
+
+    let tree = ReactDebugTools.inspectHooksOfFiber(childFiber);
+    expect(tree).toEqual([
+      {
+        isStateEditable: true,
+        id: 0,
+        name: 'State',
+        value: 'a',
+        subHooks: [],
+      },
+      {
+        isStateEditable: true,
+        id: 1,
+        name: 'Reducer',
+        value: 'b',
+        subHooks: [],
+      },
+      {isStateEditable: false, id: 2, name: 'Ref', value: 'c', subHooks: []},
+      {
+        isStateEditable: false,
+        id: 3,
+        name: 'MutationEffect',
+        value: effect,
+        subHooks: [],
+      },
+      {
+        isStateEditable: false,
+        id: 4,
+        name: 'LayoutEffect',
+        value: effect,
+        subHooks: [],
+      },
+      {
+        isStateEditable: false,
+        id: 5,
+        name: 'Effect',
+        value: effect,
+        subHooks: [],
+      },
+      {
+        isStateEditable: false,
+        id: 6,
+        name: 'ImperativeHandle',
+        value: outsideRef.current,
+        subHooks: [],
+      },
+      {
+        isStateEditable: false,
+        id: 7,
+        name: 'Memo',
+        value: 'ab',
+        subHooks: [],
+      },
+      {
+        isStateEditable: false,
+        id: 8,
+        name: 'Callback',
+        value: updateStates,
+        subHooks: [],
+      },
+    ]);
+
+    updateStates();
+
+    childFiber = renderer.root.findByType(Foo)._currentFiber();
+    tree = ReactDebugTools.inspectHooksOfFiber(childFiber);
+
+    expect(tree).toEqual([
+      {
+        isStateEditable: true,
+        id: 0,
+        name: 'State',
+        value: 'A',
+        subHooks: [],
+      },
+      {
+        isStateEditable: true,
+        id: 1,
+        name: 'Reducer',
+        value: 'B',
+        subHooks: [],
+      },
+      {isStateEditable: false, id: 2, name: 'Ref', value: 'C', subHooks: []},
+      {
+        isStateEditable: false,
+        id: 3,
+        name: 'MutationEffect',
+        value: effect,
+        subHooks: [],
+      },
+      {
+        isStateEditable: false,
+        id: 4,
+        name: 'LayoutEffect',
+        value: effect,
+        subHooks: [],
+      },
+      {
+        isStateEditable: false,
+        id: 5,
+        name: 'Effect',
+        value: effect,
+        subHooks: [],
+      },
+      {
+        isStateEditable: false,
+        id: 6,
+        name: 'ImperativeHandle',
+        value: outsideRef.current,
+        subHooks: [],
+      },
+      {
+        isStateEditable: false,
+        id: 7,
+        name: 'Memo',
+        value: 'Ab',
+        subHooks: [],
+      },
+      {
+        isStateEditable: false,
+        id: 8,
+        name: 'Callback',
+        value: updateStates,
+        subHooks: [],
+      },
+    ]);
+  });
+
   it('should inspect the value of the current provider in useContext', () => {
     const MyContext = React.createContext('default');
     function Foo(props) {

packages/react-dom/src/__tests__/ReactDOMServerIntegrationHooks-test.js

@@ -27,6 +27,7 @@ let useCallback;
 let useMemo;
 let useRef;
 let useImperativeHandle;
+let useMutationEffect;
 let useLayoutEffect;
 let useDebugValue;
 let useOpaqueIdentifier;
@@ -54,6 +55,7 @@ function initModules() {
   useRef = React.useRef;
   useDebugValue = React.useDebugValue;
   useImperativeHandle = React.useImperativeHandle;
+  useMutationEffect = React.unstable_useMutationEffect;
   useLayoutEffect = React.useLayoutEffect;
   useOpaqueIdentifier = React.unstable_useOpaqueIdentifier;
   forwardRef = React.forwardRef;
@@ -638,6 +640,22 @@ describe('ReactDOMServerHooks', () => {
       expect(domNode.textContent).toEqual('Count: 0');
     });
   });
+  describe('useMutationEffect', () => {
+    // @gate experimental || www
+    it('should warn when invoked during render', async () => {
+      function Counter() {
+        useMutationEffect(() => {
+          throw new Error('should not be invoked');
+        });
+
+        return <Text text="Count: 0" />;
+      }
+      const domNode = await serverRender(<Counter />, 1);
+      expect(clearYields()).toEqual(['Count: 0']);
+      expect(domNode.tagName).toEqual('SPAN');
+      expect(domNode.textContent).toEqual('Count: 0');
+    });
+  });
 
   describe('useLayoutEffect', () => {
     it('should warn when invoked during render', async () => {

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

@@ -385,6 +385,22 @@ function useRef<T>(initialValue: T): {|current: T|} {
   }
 }
 
+function useMutationEffect(
+  create: () => mixed,
+  inputs: Array<mixed> | void | null,
+) {
+  if (__DEV__) {
+    currentHookNameInDev = 'useMutationEffect';
+    console.error(
+      'useMutationEffect does nothing on the server, because its effect cannot ' +
+        "be encoded into the server renderer's output format. This will lead " +
+        'to a mismatch between the initial, non-hydrated UI and the intended ' +
+        'UI. To avoid this, useMutationEffect should only be used in ' +
+        'components that render exclusively on the client.',
+    );
+  }
+}
+
 export function useLayoutEffect(
   create: () => (() => void) | void,
   inputs: Array<mixed> | void | null,
@@ -501,6 +517,7 @@ export const Dispatcher: DispatcherType = {
   useReducer,
   useRef,
   useState,
+  useMutationEffect,
   useLayoutEffect,
   useCallback,
   // useImperativeHandle is not run in the server environment

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

@@ -136,6 +136,7 @@ import {
   NoFlags as NoHookEffect,
   HasEffect as HookHasEffect,
   Layout as HookLayout,
+  Mutation as HookMutation,
   Passive as HookPassive,
 } from './ReactHookEffectTags';
 import {didWarnAboutReassigningProps} from './ReactFiberBeginWork.new';
@@ -1143,7 +1144,10 @@ function commitUnmount(
           do {
             const {destroy, tag} = effect;
             if (destroy !== undefined) {
-              if ((tag & HookLayout) !== NoHookEffect) {
+              if (
+                (tag & HookMutation) !== NoHookEffect ||
+                (tag & HookLayout) !== NoHookEffect
+              ) {
                 if (
                   enableProfilerTimer &&
                   enableProfilerCommitHooks &&
@@ -1745,6 +1749,15 @@ function commitWork(current: Fiber | null, finishedWork: Fiber): void {
         ) {
           try {
             startLayoutEffectTimer();
+            commitHookEffectListUnmount(
+              HookMutation | HookHasEffect,
+              finishedWork,
+              finishedWork.return,
+            );
+            commitHookEffectListMount(
+              HookMutation | HookHasEffect,
+              finishedWork,
+            );
             commitHookEffectListUnmount(
               HookLayout | HookHasEffect,
               finishedWork,
@@ -1754,6 +1767,12 @@ function commitWork(current: Fiber | null, finishedWork: Fiber): void {
             recordLayoutEffectDuration(finishedWork);
           }
         } else {
+          commitHookEffectListUnmount(
+            HookMutation | HookHasEffect,
+            finishedWork,
+            finishedWork.return,
+          );
+          commitHookEffectListMount(HookMutation | HookHasEffect, finishedWork);
           commitHookEffectListUnmount(
             HookLayout | HookHasEffect,
             finishedWork,
@@ -1812,6 +1831,12 @@ function commitWork(current: Fiber | null, finishedWork: Fiber): void {
       ) {
         try {
           startLayoutEffectTimer();
+          commitHookEffectListUnmount(
+            HookMutation | HookHasEffect,
+            finishedWork,
+            finishedWork.return,
+          );
+          commitHookEffectListMount(HookMutation | HookHasEffect, finishedWork);
           commitHookEffectListUnmount(
             HookLayout | HookHasEffect,
             finishedWork,
@@ -1821,6 +1846,12 @@ function commitWork(current: Fiber | null, finishedWork: Fiber): void {
           recordLayoutEffectDuration(finishedWork);
         }
       } else {
+        commitHookEffectListUnmount(
+          HookMutation | HookHasEffect,
+          finishedWork,
+          finishedWork.return,
+        );
+        commitHookEffectListMount(HookMutation | HookHasEffect, finishedWork);
         commitHookEffectListUnmount(
           HookLayout | HookHasEffect,
           finishedWork,