From f50daa5ff9ad641ac3a1b469df7255b53142b176 Mon Sep 17 00:00:00 2001
From: Dan Abramov <dan.abramov@gmail.com>
Date: Mon, 21 Jan 2019 20:34:38 +0000
Subject: [PATCH] Revert "Double-render function components with Hooks in DEV
 in StrictMode" (#14652)

* Revert "Revert "Disallow reading context during useMemo etc" (#14651)"

This reverts commit 5fce6488ce1dc97e31515a47ff409d32ab722d65.

* Revert "Add test coverage for readContext() on the server (#14649)"

This reverts commit fe2ecd276e9b9e57a49ddf2d86ff01677b69b493.

* Revert "Warn about incorrect use of useImperativeHandle() (#14647)"

This reverts commit 8f45a7fdc469c6d88ca5ca105095b03dd4e862e1.

* Revert "Disallow reading context during useMemo etc (#14648)"

This reverts commit 1fcbd22431d97e404c1f684744dc543b6c22b076.

* Revert "Warn about refs on lazy function components (#14645)"

This reverts commit 2a084f51a94df30e3bffd42bf3a04ce3da231512.

* Revert "Fix typo (#14560)"

This reverts commit b5a3df6e8894ebf2334179e445b0803f6819aa9f.

* Revert "fix typo (#14316)"

This reverts commit 9c146e675174a523f90f630c87f62f55812bacea.

* Revert "Mention forwardRef() in <Fn ref={...} /> errors and warnings (#14644)"

This reverts commit baa6d40fc856c65e1d74ddf4fa038d7a65a787ed.

* Revert "Double-render function components with Hooks in DEV in StrictMode (#14643)"

This reverts commit a1414e8949915c006bba411fa2949b304dd044ae.
---
 .../src/ReactFiberBeginWork.js                |  53 -----
 .../src/__tests__/ReactHooks-test.internal.js | 220 ------------------
 2 files changed, 273 deletions(-)

diff --git a/packages/react-reconciler/src/ReactFiberBeginWork.js b/packages/react-reconciler/src/ReactFiberBeginWork.js
index 9c4a72b7fedcb..5fc0fcc871426 100644
--- a/packages/react-reconciler/src/ReactFiberBeginWork.js
+++ b/packages/react-reconciler/src/ReactFiberBeginWork.js
@@ -250,23 +250,6 @@ function updateForwardRef(
       ref,
       renderExpirationTime,
     );
-    if (
-      debugRenderPhaseSideEffects ||
-      (debugRenderPhaseSideEffectsForStrictMode &&
-        workInProgress.mode & StrictMode)
-    ) {
-      // Only double-render components with Hooks
-      if (workInProgress.memoizedState !== null) {
-        renderWithHooks(
-          current,
-          workInProgress,
-          render,
-          nextProps,
-          ref,
-          renderExpirationTime,
-        );
-      }
-    }
     setCurrentPhase(null);
   } else {
     nextChildren = renderWithHooks(
@@ -560,23 +543,6 @@ function updateFunctionComponent(
       context,
       renderExpirationTime,
     );
-    if (
-      debugRenderPhaseSideEffects ||
-      (debugRenderPhaseSideEffectsForStrictMode &&
-        workInProgress.mode & StrictMode)
-    ) {
-      // Only double-render components with Hooks
-      if (workInProgress.memoizedState !== null) {
-        renderWithHooks(
-          current,
-          workInProgress,
-          Component,
-          nextProps,
-          context,
-          renderExpirationTime,
-        );
-      }
-    }
     setCurrentPhase(null);
   } else {
     nextChildren = renderWithHooks(
@@ -1244,25 +1210,6 @@ function mountIndeterminateComponent(
   } else {
     // Proceed under the assumption that this is a function component
     workInProgress.tag = FunctionComponent;
-    if (__DEV__) {
-      if (
-        debugRenderPhaseSideEffects ||
-        (debugRenderPhaseSideEffectsForStrictMode &&
-          workInProgress.mode & StrictMode)
-      ) {
-        // Only double-render components with Hooks
-        if (workInProgress.memoizedState !== null) {
-          renderWithHooks(
-            null,
-            workInProgress,
-            Component,
-            props,
-            context,
-            renderExpirationTime,
-          );
-        }
-      }
-    }
     reconcileChildren(null, workInProgress, value, renderExpirationTime);
     if (__DEV__) {
       validateFunctionComponentInDev(workInProgress, Component);
diff --git a/packages/react-reconciler/src/__tests__/ReactHooks-test.internal.js b/packages/react-reconciler/src/__tests__/ReactHooks-test.internal.js
index 0008a27b14850..1ab149dd94c9b 100644
--- a/packages/react-reconciler/src/__tests__/ReactHooks-test.internal.js
+++ b/packages/react-reconciler/src/__tests__/ReactHooks-test.internal.js
@@ -699,224 +699,4 @@ describe('ReactHooks', () => {
       'Hooks can only be called inside the body of a function component',
     );
   });
-
-  it('double-invokes components with Hooks in Strict Mode', () => {
-    ReactFeatureFlags.debugRenderPhaseSideEffectsForStrictMode = true;
-
-    const {useState, StrictMode} = React;
-    let renderCount = 0;
-
-    function NoHooks() {
-      renderCount++;
-      return <div />;
-    }
-
-    function HasHooks() {
-      useState(0);
-      renderCount++;
-      return <div />;
-    }
-
-    const FwdRef = React.forwardRef((props, ref) => {
-      renderCount++;
-      return <div />;
-    });
-
-    const FwdRefHasHooks = React.forwardRef((props, ref) => {
-      useState(0);
-      renderCount++;
-      return <div />;
-    });
-
-    const Memo = React.memo(props => {
-      renderCount++;
-      return <div />;
-    });
-
-    const MemoHasHooks = React.memo(props => {
-      useState(0);
-      renderCount++;
-      return <div />;
-    });
-
-    function Factory() {
-      return {
-        state: {},
-        render() {
-          renderCount++;
-          return <div />;
-        },
-      };
-    }
-
-    let renderer = ReactTestRenderer.create(null);
-
-    renderCount = 0;
-    renderer.update(<NoHooks />);
-    expect(renderCount).toBe(1);
-    renderCount = 0;
-    renderer.update(<NoHooks />);
-    expect(renderCount).toBe(1);
-    renderCount = 0;
-    renderer.update(
-      <StrictMode>
-        <NoHooks />
-      </StrictMode>,
-    );
-    expect(renderCount).toBe(1);
-    renderCount = 0;
-    renderer.update(
-      <StrictMode>
-        <NoHooks />
-      </StrictMode>,
-    );
-    expect(renderCount).toBe(1);
-
-    renderCount = 0;
-    renderer.update(<FwdRef />);
-    expect(renderCount).toBe(1);
-    renderCount = 0;
-    renderer.update(<FwdRef />);
-    expect(renderCount).toBe(1);
-    renderCount = 0;
-    renderer.update(
-      <StrictMode>
-        <FwdRef />
-      </StrictMode>,
-    );
-    expect(renderCount).toBe(1);
-    renderCount = 0;
-    renderer.update(
-      <StrictMode>
-        <FwdRef />
-      </StrictMode>,
-    );
-    expect(renderCount).toBe(1);
-
-    renderCount = 0;
-    renderer.update(<Memo arg={1} />);
-    expect(renderCount).toBe(1);
-    renderCount = 0;
-    renderer.update(<Memo arg={2} />);
-    expect(renderCount).toBe(1);
-    renderCount = 0;
-    renderer.update(
-      <StrictMode>
-        <Memo arg={1} />
-      </StrictMode>,
-    );
-    expect(renderCount).toBe(1);
-    renderCount = 0;
-    renderer.update(
-      <StrictMode>
-        <Memo arg={2} />
-      </StrictMode>,
-    );
-    expect(renderCount).toBe(1);
-
-    renderCount = 0;
-    renderer.update(<Factory />);
-    expect(renderCount).toBe(1);
-    renderCount = 0;
-    renderer.update(<Factory />);
-    expect(renderCount).toBe(1);
-    renderCount = 0;
-    renderer.update(
-      <StrictMode>
-        <Factory />
-      </StrictMode>,
-    );
-    expect(renderCount).toBe(__DEV__ ? 2 : 1); // Treated like a class
-    renderCount = 0;
-    renderer.update(
-      <StrictMode>
-        <Factory />
-      </StrictMode>,
-    );
-    expect(renderCount).toBe(__DEV__ ? 2 : 1); // Treated like a class
-
-    renderCount = 0;
-    renderer.update(<HasHooks />);
-    expect(renderCount).toBe(1);
-    renderCount = 0;
-    renderer.update(<HasHooks />);
-    expect(renderCount).toBe(1);
-    renderCount = 0;
-    renderer.update(
-      <StrictMode>
-        <HasHooks />
-      </StrictMode>,
-    );
-    expect(renderCount).toBe(__DEV__ ? 2 : 1); // Has Hooks
-    renderCount = 0;
-    renderer.update(
-      <StrictMode>
-        <HasHooks />
-      </StrictMode>,
-    );
-    expect(renderCount).toBe(__DEV__ ? 2 : 1); // Has Hooks
-
-    renderCount = 0;
-    renderer.update(<FwdRefHasHooks />);
-    expect(renderCount).toBe(1);
-    renderCount = 0;
-    renderer.update(<FwdRefHasHooks />);
-    expect(renderCount).toBe(1);
-    renderCount = 0;
-    renderer.update(
-      <StrictMode>
-        <FwdRefHasHooks />
-      </StrictMode>,
-    );
-    expect(renderCount).toBe(__DEV__ ? 2 : 1); // Has Hooks
-    renderCount = 0;
-    renderer.update(
-      <StrictMode>
-        <FwdRefHasHooks />
-      </StrictMode>,
-    );
-    expect(renderCount).toBe(__DEV__ ? 2 : 1); // Has Hooks
-
-    renderCount = 0;
-    renderer.update(<MemoHasHooks arg={1} />);
-    expect(renderCount).toBe(1);
-    renderCount = 0;
-    renderer.update(<MemoHasHooks arg={2} />);
-    expect(renderCount).toBe(1);
-    renderCount = 0;
-    renderer.update(
-      <StrictMode>
-        <MemoHasHooks arg={1} />
-      </StrictMode>,
-    );
-    expect(renderCount).toBe(__DEV__ ? 2 : 1); // Has Hooks
-    renderCount = 0;
-    renderer.update(
-      <StrictMode>
-        <MemoHasHooks arg={2} />
-      </StrictMode>,
-    );
-    expect(renderCount).toBe(__DEV__ ? 2 : 1); // Has Hooks
-  });
-
-  it('double-invokes useMemo in DEV StrictMode despite []', () => {
-    ReactFeatureFlags.debugRenderPhaseSideEffectsForStrictMode = true;
-    const {useMemo, StrictMode} = React;
-
-    let useMemoCount = 0;
-    function BadUseMemo() {
-      useMemo(() => {
-        useMemoCount++;
-      }, []);
-      return <div />;
-    }
-
-    useMemoCount = 0;
-    ReactTestRenderer.create(
-      <StrictMode>
-        <BadUseMemo />
-      </StrictMode>,
-    );
-    expect(useMemoCount).toBe(__DEV__ ? 2 : 1); // Has Hooks
-  });
 });