fix: React.use inside React.lazy-ed component on SSR
#33941
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/cc @acdlite |
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cc @eps1lon |
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Comparing: dffacc7...dc09e25 Critical size changesIncludes critical production bundles, as well as any change greater than 2%:
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eps1lon
approved these changes
Jul 28, 2025
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It's unfortunate because we need the thenable state for other debug info. However, there's a general problem with "throw a Promise" and debugging that leads us to wanting to deprecate the whole feature anyway. |
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Summary
React.useinsideReact.lazy-ed component returns otherReact.usevalue on SSR #33937As indicated by the previous issue comment #27731 (comment), it looks like legacy "throw thenable"-based suspense implementation (used by React.lazy) causes an issue with
React.usebased suspense implementation, which relies onthenableStatehook state tracking.The PR fixes the issue by avoiding
getThenableStateAfterSuspendingwhen legacy "throw thenable" style suspension happened. I tried a different approach such as resettingtask.thenableState = nullduringrenderLazyComponent, but it broke one test caseuseActionState can return binary state during MPA form submissioninpackages/react-server-dom-webpack/src/__tests__/ReactFlightDOMForm-test.js.(By no means, I'm confident with the change, but I thought poking around the code provides better insight for short term workaround. See #33937 (comment). I'd appreciate any help on the issue.)
How did you test this change?
I added a test case in
packages/react-dom/src/__tests__/ReactDOMFizzServer-test.jsbased on the reproduction of the issue (and also #33938).