remove optimistic navigation behavior when prefetch is false

packages/next/src/client/components/app-router.tsx

@@ -204,15 +204,14 @@ function useChangeByServerResponse(
 
 function useNavigate(dispatch: React.Dispatch<ReducerActions>): RouterNavigate {
   return useCallback(
-    (href, navigateType, forceOptimisticNavigation, shouldScroll) => {
+    (href, navigateType, shouldScroll) => {
       const url = new URL(addBasePath(href), location.href)
 
       return dispatch({
         type: ACTION_NAVIGATE,
         url,
         isExternalUrl: isExternalURL(url),
         locationSearch: location.search,
-        forceOptimisticNavigation,
         shouldScroll: shouldScroll ?? true,
         navigateType,
         cache: createEmptyCacheNode(),
@@ -330,22 +329,12 @@ function Router({
       },
       replace: (href, options = {}) => {
         startTransition(() => {
-          navigate(
-            href,
-            'replace',
-            Boolean(options.forceOptimisticNavigation),
-            options.scroll ?? true
-          )
+          navigate(href, 'replace', options.scroll ?? true)
         })
       },
       push: (href, options = {}) => {
         startTransition(() => {
-          navigate(
-            href,
-            'push',
-            Boolean(options.forceOptimisticNavigation),
-            options.scroll ?? true
-          )
+          navigate(href, 'push', options.scroll ?? true)
         })
       },
       refresh: () => {

packages/next/src/client/components/router-reducer/fill-cache-with-data-property.ts

@@ -11,9 +11,8 @@ export function fillCacheWithDataProperty(
   newCache: CacheNode,
   existingCache: CacheNode,
   flightSegmentPath: FlightSegmentPath,
-  fetchResponse: () => Promise<FetchServerResponseResult>,
-  bailOnParallelRoutes: boolean = false
-): { bailOptimistic: boolean } | undefined {
+  fetchResponse: () => Promise<FetchServerResponseResult>
+): void {
   const isLastEntry = flightSegmentPath.length <= 2
 
   const [parallelRouteKey, segment] = flightSegmentPath
@@ -22,24 +21,14 @@ export function fillCacheWithDataProperty(
   const existingChildSegmentMap =
     existingCache.parallelRoutes.get(parallelRouteKey)
 
-  if (
-    !existingChildSegmentMap ||
-    (bailOnParallelRoutes && existingCache.parallelRoutes.size > 1)
-  ) {
-    // Bailout because the existing cache does not have the path to the leaf node
-    // or the existing cache has multiple parallel routes
-    // Will trigger lazy fetch in layout-router because of missing segment
-    return { bailOptimistic: true }
-  }
-
   let childSegmentMap = newCache.parallelRoutes.get(parallelRouteKey)
 
   if (!childSegmentMap || childSegmentMap === existingChildSegmentMap) {
     childSegmentMap = new Map(existingChildSegmentMap)
     newCache.parallelRoutes.set(parallelRouteKey, childSegmentMap)
   }
 
-  const existingChildCacheNode = existingChildSegmentMap.get(cacheKey)
+  const existingChildCacheNode = existingChildSegmentMap?.get(cacheKey)
   let childCacheNode = childSegmentMap.get(cacheKey)
 
   // In case of last segment start off the fetch at this level and don't copy further down.