[React 19] Prewarm with use() broken in certain state-change situations in the parent

[Ephem]

Summary

When testing the new prewarming, I ran across a situation where an effect / state change in the parent seems to break prewarming. This only happens with use(), not with throw promise:

https://codesandbox.io/p/sandbox/sibling-suspense-use-reproduction-lmscnl

I have not explored exactly under which circumstances this happens.

I did not find this in a real app, it happened when I was testing edge cases with React Query and noticed useSuspenseQuery worked as expected (throw promise) and { promise } = useQuery(...); use(promise) did not in one case.

I am not sure this is a bug or intentional behaviour, but wanted to file it since it behaves differently with use(promise) and throw promise.

[aalmanasir]

Bug