fix: restore immediate state sync so useIsPending works during transitions#78
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fix: restore immediate state sync so useIsPending works during transitions#78
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…tions The `entryInitValue` sentinel made `locationEntry` delegate to `useSyncExternalStore` (via `initialEntry`) until the first navigation event committed. Because `useSyncExternalStore` always reflects the latest adapter snapshot — even during a transition's fallback render — React could never show the old route with `isPending=true`; instead the suspending new route was rendered in both the transition and the fallback, defeating `useTransition` entirely. Fix by restoring the immediate `setLocationEntry(adapter.getSnapshot())` call in the subscription effect (removed in 4a4ef2c as "redundant"). This locks a real value into `useState` before any navigation occurs, so subsequent `startTransition` updates have a proper old state to fall back to. With the immediate sync back, the `entryInitValue` indirection is no longer needed and is removed. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Summary
useIsPendingnever returningtrueduring transitions caused by a suspending route. TheentryInitValuesentinel delegatedlocationEntrytouseSyncExternalStore, which always reflects the latest adapter snapshot — even in a transition's fallback render — so React could never show the old route withisPending=true.setLocationEntry(adapter.getSnapshot())call in the subscription effect (removed in 4a4ef2c as "redundant"), which locks a real value intouseStatebefore any navigation, givingstartTransitiona proper old state to fall back to.entryInitValueindirection (Symbolsentinel,locationEntryInternal, ternary fallback) which is no longer needed with the immediate sync back in place.Test plan
pnpm test:run— all 177 tests pass, including the previously failinguseIsPending > returns true when a navigation transition is pending due to a suspending route🤖 Generated with Claude Code