{"files":[{"path":"packages\/react-reconciler\/src\/ReactFiberBeginWork.js","status":"M"},{"path":"packages\/react-refresh\/src\/__tests__\/ReactFresh-test.js","status":"M"}],"body":"","parents":["67e47593b607ecc08ac59361d8aba7ad2eef028a"],"commit":{"shortRevision":"da9325b519","authorName":"Sebastian \"Sebbie\" Silbermann","revision":"da9325b519376e2d65cdf6d509ade053e14ec5b3","authoredAt":"2026-04-17T18:14:50+02:00","subject":"[Fiber] Double invoke Effects in StrictMode after Fast Refresh (#35962)","authorEmail":"sebastian.silbermann@vercel.com"},"patch":"diff --git a\/packages\/react-reconciler\/src\/ReactFiberBeginWork.js b\/packages\/react-reconciler\/src\/ReactFiberBeginWork.js\nindex b8709c03a4..4f41a70e56 100644\n--- a\/packages\/react-reconciler\/src\/ReactFiberBeginWork.js\n+++ b\/packages\/react-reconciler\/src\/ReactFiberBeginWork.js\n@@ -3866,7 +3866,7 @@ function remountFiber(\n deletions.push(current);\n }\n \n- newWorkInProgress.flags |= Placement;\n+ newWorkInProgress.flags |= Placement | PlacementDEV;\n \n \/\/ Restart work from the new fiber.\n return newWorkInProgress;\ndiff --git a\/packages\/react-refresh\/src\/__tests__\/ReactFresh-test.js b\/packages\/react-refresh\/src\/__tests__\/ReactFresh-test.js\nindex 6fb00a66a2..e0f2d49033 100644\n--- a\/packages\/react-refresh\/src\/__tests__\/ReactFresh-test.js\n+++ b\/packages\/react-refresh\/src\/__tests__\/ReactFresh-test.js\n@@ -2326,6 +2326,98 @@ describe('ReactFresh', () => {\n expect(finalEl.style.color).toBe('orange');\n }\n \n+ it('double invokes effects after a forced remount in StrictMode', async () => {\n+ if (__DEV__) {\n+ const log = [];\n+\n+ const createAppV1 = () => {\n+ function Hello() {\n+ React.useEffect(() => {\n+ log.push('mount v1');\n+ return () => log.push('unmount v1');\n+ }, []);\n+ return

Hello<\/p>;\n+ }\n+ $RefreshReg$(Hello, 'Hello');\n+ $RefreshSig$(Hello, '1');\n+\n+ return Hello;\n+ };\n+\n+ const App = createAppV1();\n+\n+ await act(() => {\n+ root.render(\n+ \n+ \n+ <\/React.StrictMode>,\n+ );\n+ });\n+\n+ expect(log).toEqual(['mount v1', 'unmount v1', 'mount v1']);\n+ log.length = 0;\n+\n+ await patch(() => {\n+ function Hello() {\n+ React.useEffect(() => {\n+ log.push('mount v2');\n+ return () => log.push('unmount v2');\n+ }, []);\n+ return

Hello<\/p>;\n+ }\n+ $RefreshReg$(Hello, 'Hello');\n+ $RefreshSig$(Hello, '2');\n+ return null;\n+ });\n+\n+ expect(container.firstChild.style.color).toBe('red');\n+ expect(log).toEqual(['unmount v1', 'mount v2', 'unmount v2', 'mount v2']);\n+ }\n+ });\n+\n+ it('double invokes an effect added during Fast Refresh remount in StrictMode', async () => {\n+ if (__DEV__) {\n+ const log = [];\n+\n+ const createAppV1 = () => {\n+ function Hello() {\n+ return

Hello<\/p>;\n+ }\n+ $RefreshReg$(Hello, 'Hello');\n+ $RefreshSig$(Hello, '1');\n+ return Hello;\n+ };\n+\n+ const App = createAppV1();\n+\n+ await act(() => {\n+ root.render(\n+ \n+ \n+ <\/React.StrictMode>,\n+ );\n+ });\n+\n+ expect(log).toEqual([]);\n+\n+ await patch(() => {\n+ function Hello() {\n+ React.useEffect(() => {\n+ log.push('mount v2');\n+ return () => log.push('unmount v2');\n+ }, []);\n+ return

Hello<\/p>;\n+ }\n+ $RefreshReg$(Hello, 'Hello');\n+ $RefreshSig$(Hello, '2');\n+ return null;\n+ });\n+\n+ expect(container.firstChild.style.color).toBe('red');\n+ expect(log).toEqual(['mount v2', 'unmount v2', 'mount v2']);\n+ }\n+ });\n+\n it('resets hooks with dependencies on hot reload', async () => {\n if (__DEV__) {\n let useEffectWithEmptyArrayCalls = 0;\n"}

dillon1000/react

Files changed