Hold cacheSignal across unstable_cache foreground revalidation#93617
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When `unstable_cache` finds a stale entry during the prospective phase of a prerender, it dispatches a foreground revalidation and returns the in-flight promise. The wrapper's `cacheSignal.beginRead` / `endRead` pair was scoped only to the synchronous lookup — `endRead` in the outer `finally` fires the moment the function returns the promise, before the recompute and `cacheNewResult` have run. The prospective prerender's `cacheSignal` then resolves `cacheReady` while the recompute is still in flight, ending the prospective phase early. Any `'use cache'` invocation rendered after the `unstable_cache` await in the same component never gets reached, so its RDC entry is never populated, and the final prerender phase throws "Unexpected cache miss after cache warming phase during prerendering." Returning `await pendingRevalidates[invocationKey]` instead of returning the promise directly keeps the wrapper function suspended until the recompute and `cacheNewResult` actually complete. The outer `finally` then runs `endRead` at the right time, the prospective phase keeps waiting, and downstream `'use cache'` invocations are reached and populate the RDC as expected. Adds a regression test under the `use-cache` suite that exercises an `unstable_cache` await followed by a downstream `'use cache'` component; without the fix, the test fails consistently under `__NEXT_CACHE_COMPONENTS=true` with the cache-miss-after-warming error.
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gnoff
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May 7, 2026
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…93617) When `unstable_cache` finds a stale entry during the prospective phase of a prerender, it dispatches a foreground revalidation and returns the in-flight promise. The wrapper's `cacheSignal.beginRead` / `endRead` pair was scoped only to the synchronous lookup.`endRead` in the outer `finally` fires the moment the function returns the promise, before the recompute and `cacheNewResult` have completed. The prospective prerender's `cacheSignal` then resolves `cacheReady` while the recompute is still in flight, ending the prospective phase early. Any `'use cache'` invocation rendered after the `unstable_cache` await in the same component never gets reached, so its RDC entry is never populated, and the final prerender phase throws "Unexpected cache miss after cache warming phase during prerendering." Returning `await pendingRevalidates[invocationKey]` instead of returning the promise directly keeps the wrapper function suspended until the recompute and `cacheNewResult` actually complete. The outer `finally` then runs `endRead` at the right time, the prospective phase keeps waiting, and downstream `'use cache'` invocations are reached and populate the RDC as expected. Adds a regression test under the `use-cache` suite that exercises an `unstable_cache` await followed by a downstream `'use cache'` component. Without the fix, the test fails consistently under `__NEXT_CACHE_COMPONENTS=true` with the cache-miss-after-warming error.
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…93617) When `unstable_cache` finds a stale entry during the prospective phase of a prerender, it dispatches a foreground revalidation and returns the in-flight promise. The wrapper's `cacheSignal.beginRead` / `endRead` pair was scoped only to the synchronous lookup.`endRead` in the outer `finally` fires the moment the function returns the promise, before the recompute and `cacheNewResult` have completed. The prospective prerender's `cacheSignal` then resolves `cacheReady` while the recompute is still in flight, ending the prospective phase early. Any `'use cache'` invocation rendered after the `unstable_cache` await in the same component never gets reached, so its RDC entry is never populated, and the final prerender phase throws "Unexpected cache miss after cache warming phase during prerendering." Returning `await pendingRevalidates[invocationKey]` instead of returning the promise directly keeps the wrapper function suspended until the recompute and `cacheNewResult` actually complete. The outer `finally` then runs `endRead` at the right time, the prospective phase keeps waiting, and downstream `'use cache'` invocations are reached and populate the RDC as expected. Adds a regression test under the `use-cache` suite that exercises an `unstable_cache` await followed by a downstream `'use cache'` component. Without the fix, the test fails consistently under `__NEXT_CACHE_COMPONENTS=true` with the cache-miss-after-warming error.
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When
unstable_cachefinds a stale entry during the prospective phase of a prerender, it dispatches a foreground revalidation and returns the in-flight promise. The wrapper'scacheSignal.beginRead/endReadpair was scoped only to the synchronous lookup.endReadin the outerfinallyfires the moment the function returns the promise, before the recompute andcacheNewResulthave completed. The prospective prerender'scacheSignalthen resolvescacheReadywhile the recompute is still in flight, ending the prospective phase early. Any'use cache'invocation rendered after theunstable_cacheawait in the same component never gets reached, so its RDC entry is never populated, and the final prerender phase throws "Unexpected cache miss after cache warming phase during prerendering."Returning
await pendingRevalidates[invocationKey]instead of returning the promise directly keeps the wrapper function suspended until the recompute andcacheNewResultactually complete. The outerfinallythen runsendReadat the right time, the prospective phase keeps waiting, and downstream'use cache'invocations are reached and populate the RDC as expected.Adds a regression test under the
use-cachesuite that exercises anunstable_cacheawait followed by a downstream'use cache'component. Without the fix, the test fails consistently under__NEXT_CACHE_COMPONENTS=truewith the cache-miss-after-warming error.