Re-implement Server Action reducer

WIP

Author: acdlite

packages/next/src/client/components/router-reducer/ppr-navigations.ts

@@ -88,6 +88,8 @@ export function startPPRNavigation(
   oldRouterState: FlightRouterState,
   newRouterState: FlightRouterState,
   shouldRefreshDynamicData: boolean,
+  seedData: CacheNodeSeedData | null,
+  seedHead: HeadData | null,
   prefetchData: CacheNodeSeedData | null,
   prefetchHead: HeadData | null,
   isPrefetchHeadPartial: boolean,
@@ -106,6 +108,8 @@ export function startPPRNavigation(
     newRouterState,
     shouldRefreshDynamicData,
     didFindRootLayout,
+    seedData,
+    seedHead,
     prefetchData,
     prefetchHead,
     isPrefetchHeadPartial,
@@ -125,6 +129,8 @@ function updateCacheNodeOnNavigation(
   newRouterState: FlightRouterState,
   shouldRefreshDynamicData: boolean,
   didFindRootLayout: boolean,
+  seedData: CacheNodeSeedData | null,
+  seedHead: HeadData | null,
   prefetchData: CacheNodeSeedData | null,
   prefetchHead: HeadData | null,
   isPrefetchHeadPartial: boolean,
@@ -146,6 +152,8 @@ function updateCacheNodeOnNavigation(
 
     // Since we're switching to a different route tree, these are no
     // longer valid, because they correspond to the outer tree.
+    seedData = null
+    seedHead = null
     prefetchData = null
     prefetchHead = null
     isPrefetchHeadPartial = false
@@ -183,6 +191,8 @@ function updateCacheNodeOnNavigation(
       newRouterState,
       oldCacheNode,
       shouldRefreshDynamicData,
+      seedData,
+      seedHead,
       prefetchData,
       prefetchHead,
       isPrefetchHeadPartial,
@@ -194,6 +204,7 @@ function updateCacheNodeOnNavigation(
 
   const newRouterStateChildren = newRouterState[1]
   const oldRouterStateChildren = oldRouterState[1]
+  const seedDataChildren = seedData !== null ? seedData[1] : null
   const prefetchDataChildren = prefetchData !== null ? prefetchData[1] : null
 
   // We're currently traversing the part of the tree that was also part of
@@ -242,6 +253,28 @@ function updateCacheNodeOnNavigation(
     // Reuse the existing CacheNode
     newCacheNode = reuseDynamicCacheNode(oldCacheNode, newParallelRoutes)
     needsDynamicRequest = false
+  } else if (seedData !== null) {
+    // If this navigation was the result of an action, then check if the
+    // server sent back data in the action response. We should favor using
+    // that, rather than performing a separate request. This is both better
+    // for performance and it's more likely to be consistent with any
+    // writes that were just performed by the action, compared to a
+    // separate request.
+    const seedRsc = seedData[0]
+    const seedLoading = seedData[2]
+    const isSeedRscPartial = false
+    const isSeedHeadPartial = seedHead !== null
+    newCacheNode = readCacheNodeFromSeedData(
+      seedRsc,
+      seedLoading,
+      isSeedRscPartial,
+      seedHead,
+      isSeedHeadPartial,
+      isLeafSegment,
+      newParallelRoutes,
+      navigatedAt
+    )
+    needsDynamicRequest = isLeafSegment && isSeedHeadPartial
   } else if (prefetchData !== null) {
     // Consult the prefetch cache.
     const prefetchRsc = prefetchData[0]
@@ -335,6 +368,8 @@ function updateCacheNodeOnNavigation(
       oldParallelRoutes !== undefined
         ? oldParallelRoutes.get(parallelRouteKey)
         : undefined
+    const seedDataChild: CacheNodeSeedData | void | null =
+      seedDataChildren !== null ? seedDataChildren[parallelRouteKey] : null
     const prefetchDataChild: CacheNodeSeedData | void | null =
       prefetchDataChildren !== null
         ? prefetchDataChildren[parallelRouteKey]
@@ -360,6 +395,8 @@ function updateCacheNodeOnNavigation(
       newRouterStateChild,
       shouldRefreshDynamicData,
       childDidFindRootLayout,
+      seedDataChild ?? null,
+      seedHead,
       prefetchDataChild ?? null,
       prefetchHead,
       isPrefetchHeadPartial,
@@ -384,7 +421,9 @@ function updateCacheNodeOnNavigation(
     taskChildren.set(parallelRouteKey, taskChild)
     const newCacheNodeChild = taskChild.node
     if (newCacheNodeChild !== null) {
-      const newSegmentMapChild: ChildSegmentMap = new Map(oldSegmentMapChild)
+      const newSegmentMapChild: ChildSegmentMap = new Map(
+        shouldRefreshDynamicData ? undefined : oldSegmentMapChild
+      )
       newSegmentMapChild.set(newSegmentKeyChild, newCacheNodeChild)
       newParallelRoutes.set(parallelRouteKey, newSegmentMapChild)
     }
@@ -434,6 +473,8 @@ function createCacheNodeOnNavigation(
   newRouterState: FlightRouterState,
   oldCacheNode: CacheNode | void,
   shouldRefreshDynamicData: boolean,
+  seedData: CacheNodeSeedData | null,
+  seedHead: HeadData | null,
   prefetchData: CacheNodeSeedData | null,
   prefetchHead: HeadData | null,
   isPrefetchHeadPartial: boolean,
@@ -452,6 +493,7 @@ function createCacheNodeOnNavigation(
   // diverges, which is why we keep them separate.
   const newRouterStateChildren = newRouterState[1]
   const prefetchDataChildren = prefetchData !== null ? prefetchData[1] : null
+  const seedDataChildren = seedData !== null ? seedData[1] : null
   const oldParallelRoutes =
     oldCacheNode !== undefined ? oldCacheNode.parallelRoutes : undefined
   const newParallelRoutes = new Map(
@@ -489,6 +531,28 @@ function createCacheNodeOnNavigation(
     // Reuse the existing CacheNode
     newCacheNode = reuseDynamicCacheNode(oldCacheNode, newParallelRoutes)
     needsDynamicRequest = false
+  } else if (seedData !== null) {
+    // If this navigation was the result of an action, then check if the
+    // server sent back data in the action response. We should favor using
+    // that, rather than performing a separate request. This is both better
+    // for performance and it's more likely to be consistent with any
+    // writes that were just performed by the action, compared to a
+    // separate request.
+    const seedRsc = seedData[0]
+    const seedLoading = seedData[2]
+    const isSeedRscPartial = false
+    const isSeedHeadPartial = seedHead !== null
+    newCacheNode = readCacheNodeFromSeedData(
+      seedRsc,
+      seedLoading,
+      isSeedRscPartial,
+      seedHead,
+      isSeedHeadPartial,
+      isLeafSegment,
+      newParallelRoutes,
+      navigatedAt
+    )
+    needsDynamicRequest = isLeafSegment && isSeedHeadPartial
   } else if (prefetchData !== null) {
     // Consult the prefetch cache.
     const prefetchRsc = prefetchData[0]
@@ -533,6 +597,8 @@ function createCacheNodeOnNavigation(
       oldParallelRoutes !== undefined
         ? oldParallelRoutes.get(parallelRouteKey)
         : undefined
+    const seedDataChild: CacheNodeSeedData | void | null =
+      seedDataChildren !== null ? seedDataChildren[parallelRouteKey] : null
     const prefetchDataChild: CacheNodeSeedData | void | null =
       prefetchDataChildren !== null
         ? prefetchDataChildren[parallelRouteKey]
@@ -555,6 +621,8 @@ function createCacheNodeOnNavigation(
       newRouterStateChild,
       oldCacheNodeChild,
       shouldRefreshDynamicData,
+      seedDataChild ?? null,
+      seedHead,
       prefetchDataChild ?? null,
       prefetchHead,
       isPrefetchHeadPartial,
@@ -569,7 +637,9 @@ function createCacheNodeOnNavigation(
     taskChildren.set(parallelRouteKey, taskChild)
     const newCacheNodeChild = taskChild.node
     if (newCacheNodeChild !== null) {
-      const newSegmentMapChild: ChildSegmentMap = new Map(oldSegmentMapChild)
+      const newSegmentMapChild: ChildSegmentMap = new Map(
+        shouldRefreshDynamicData ? undefined : oldSegmentMapChild
+      )
       newSegmentMapChild.set(newSegmentKeyChild, newCacheNodeChild)
       newParallelRoutes.set(parallelRouteKey, newSegmentMapChild)
     }

packages/next/src/client/components/router-reducer/reducers/refresh-reducer.ts

@@ -5,7 +5,7 @@ import type {
   RefreshAction,
 } from '../router-reducer-types'
 import { handleNavigationResult } from './navigate-reducer'
-import { refresh as refreshUsingSegmentCache } from '../../segment-cache/navigation'
+import { navigateToSeededRoute } from '../../segment-cache/navigation'
 import { revalidateEntireCache } from '../../segment-cache/cache'
 
 export function refreshReducer(
@@ -19,14 +19,31 @@ export function refreshReducer(
   const currentRouterState = state.tree
   revalidateEntireCache(currentNextUrl, currentRouterState)
 
+  // A refresh is modeled as a navigation to the current URL, but where any
+  // existing dynamic data (including in shared layouts) is re-fetched.
   const currentUrl = new URL(state.canonicalUrl, action.origin)
-  const result = refreshUsingSegmentCache(
+  const url = currentUrl
+  const currentFlightRouterState = state.tree
+  const shouldScroll = true
+  const shouldRefreshDynamicData = true
+
+  const seedFlightRouterState = state.tree
+  const seedData = null
+  const seedHead = null
+
+  const result = navigateToSeededRoute(
+    url,
     currentUrl,
     state.cache,
-    state.tree,
+    currentFlightRouterState,
+    seedFlightRouterState,
+    seedData,
+    seedHead,
+    shouldRefreshDynamicData,
     state.nextUrl,
     state.renderedSearch,
-    state.canonicalUrl
+    state.canonicalUrl,
+    shouldScroll
   )
 
   const mutable: Mutable = {}