FIX: Context pollutes mutable global state (with "thread local storage") #13877
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The new context API stores the provided values on the shared context instance. When used in a synchronous context, this is not an issue. However when used in an concurrent context this can cause a "push provider" from one react render to have an effect on an unrelated concurrent react render. I've encountered this bug in production when using renderToNodeStream, which asks ReactPartialRenderer for bytes up to a high water mark before yielding. If two Node Streams are created and read from in parallel, the state of one can polute the other. I wrote a failing test to illustrate the conditions under which this happens. I'm also concerned that the experimental concurrent/async React rendering on the client could suffer from the same issue.
…storage") Fixes facebook#13874 Alternative to facebook#13875 This straw-man approach also avoids mutating global context by giving each ReactPartialRenderer it's own mutable state and using context instances as keys into that mutable state.
Details of bundled changes.Comparing: 4f0bd45...1e5100e react-dom
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leebyron
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Hey @sebmarkbage, how are you all thinking of the next version cut. Is there any chance of getting this into a patch release? |
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Landed #14182 instead but would be good to perf test both to validate the theory. |
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Fixes #13874
Alternative to #13875
This straw-man approach also avoids mutating global context by giving each ReactPartialRenderer its own mutable state and using context instances as keys into that mutable state.