fix(router): preserve scroll:false across async PPR retry navigations (force-dynamic)#94943
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sleitor wants to merge 1 commit into
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fix(router): preserve scroll:false across async PPR retry navigations (force-dynamic)#94943sleitor wants to merge 1 commit into
sleitor wants to merge 1 commit into
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When a force-dynamic page triggers a tree mismatch during a PPR navigation, the retry (ACTION_SERVER_PATCH) was hardcoding ScrollBehavior.Default, discarding the original scroll:false option. Thread scrollBehavior through the async retry chain: - spawnDynamicRequests() → finishNavigationTask() - finishNavigationTask() → dispatchRetryDueToTreeMismatch() - dispatchRetryDueToTreeMismatch() → ServerPatchAction.scrollBehavior - serverPatchReducer() reads action.scrollBehavior ?? Default Also update restore-reducer.ts which also calls spawnDynamicRequests() (history traversal, passes ScrollBehavior.Default). Fixes vercel#94893
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What?
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scrollBehaviorthrough the async PPR retry chain so thatscroll: falsepassed torouter.replace()(orrouter.push()) is preserved when a force-dynamic page triggers a tree mismatch and the navigation falls back toACTION_SERVER_PATCH.Why?
On force-dynamic pages with PPR enabled, every navigation that hits an optimistic route cache entry ends up in a tree mismatch →
dispatchRetryDueToTreeMismatch→serverPatchReducer. Before this fix,serverPatchReducerhardcodedScrollBehavior.Defaultregardless of the original navigation'sscroll: falseoption, causing the page to scroll back to the top on every navigation.The bug only triggers in production (prefetching is disabled in dev) and only after the user has prefetched the root route (e.g. by hovering over a
<Link href="/">), which is why it's subtle.How?
scrollBehavior?: ScrollBehaviortoServerPatchActioninrouter-reducer-types.ts.scrollBehaviorparameter tospawnDynamicRequests()(afternavigationLock).spawnDynamicRequests→finishNavigationTask→dispatchRetryDueToTreeMismatch→ServerPatchAction.scrollBehavior.serverPatchReducer, readaction.scrollBehavior ?? ScrollBehavior.Defaultinstead of always usingDefault.restore-reducer.ts(the only other caller ofspawnDynamicRequests) to passScrollBehavior.Default— history traversal already defaults to no-scroll behavior.Fixes #94893