Remove revalidate property from incremental cache ctx for FETCH

The `revalidate` property of the `ctx` object that is passed into the
incremental cache by the patched `fetch` as well as `unstable_cache`
is unused since it was introduced in #43659. It was just added because
of how the method signature for `set()` was changed back then.

However, for those kinds of cache entries, the `revalidate` context
property is never used, and instead the `revalidate` property of the
passed-in `data` is used.

To avoid further confusion (e.g. in [this
question](#76207 (comment))),
this PR improves the method signatures and types of the incremental
cache so that the different call-site use cases can be clearly
discriminated, and superfluous context properties can be omitted.

packages/next/errors.json

@@ -649,5 +649,7 @@
   "648": "@rspack/plugin-react-refresh is not available. Please make sure `@next/plugin-rspack` is correctly installed.",
   "649": "Cache handlers not initialized",
   "650": "experimental.nodeMiddleware",
-  "651": "Unexpected module type %s"
+  "651": "Unexpected module type %s",
+  "652": "Expected cached value for cache key %s not to be a %s kind, got \"FETCH\" instead.",
+  "653": "Expected cached value for cache key %s to be a \"FETCH\" kind, got %s instead."
 }

packages/next/src/server/image-optimizer.ts

@@ -19,8 +19,8 @@ import {
   CachedRouteKind,
   type CachedImageValue,
   type IncrementalCacheEntry,
-  type IncrementalCacheItem,
   type IncrementalCacheValue,
+  type IncrementalResponseCacheEntry,
 } from './response-cache'
 import { sendEtagResponse } from './send-payload'
 import { getContentType, getExtension } from './serve-static'
@@ -390,7 +390,7 @@ export class ImageOptimizerCache {
     this.nextConfig = nextConfig
   }
 
-  async get(cacheKey: string): Promise<IncrementalCacheEntry | null> {
+  async get(cacheKey: string): Promise<IncrementalResponseCacheEntry | null> {
     try {
       const cacheDir = join(this.cacheDir, cacheKey)
       const files = await promises.readdir(cacheDir)
@@ -414,7 +414,7 @@ export class ImageOptimizerCache {
           revalidateAfter:
             Math.max(maxAge, this.nextConfig.images.minimumCacheTTL) * 1000 +
             Date.now(),
-          curRevalidate: maxAge,
+          revalidate: maxAge,
           isStale: now > expireAt,
           isFallback: false,
         }
@@ -508,7 +508,7 @@ export function getMaxAge(str: string | null | undefined): number {
 }
 export function getPreviouslyCachedImageOrNull(
   upstreamImage: ImageUpstream,
-  previousCacheEntry: IncrementalCacheItem | undefined
+  previousCacheEntry: IncrementalCacheEntry | null | undefined
 ): CachedImageValue | null {
   if (
     previousCacheEntry?.value?.kind === 'IMAGE' &&
@@ -678,7 +678,7 @@ export async function imageOptimizer(
   opts: {
     isDev?: boolean
     silent?: boolean
-    previousCacheEntry?: IncrementalCacheItem
+    previousCacheEntry?: IncrementalResponseCacheEntry | null
   }
 ): Promise<{
   buffer: Buffer
@@ -772,7 +772,7 @@ export async function imageOptimizer(
     return {
       buffer: previouslyCachedImage.buffer,
       contentType,
-      maxAge: opts?.previousCacheEntry?.curRevalidate || maxAge,
+      maxAge: opts?.previousCacheEntry?.revalidate || maxAge,
       etag: previouslyCachedImage.etag,
       upstreamEtag: previouslyCachedImage.upstreamEtag,
     }

packages/next/src/server/lib/incremental-cache/file-system-cache.ts

@@ -5,6 +5,9 @@ import {
   CachedRouteKind,
   IncrementalCacheKind,
   type CachedFetchValue,
+  type IncrementalCacheValue,
+  type SetIncrementalFetchCacheContext,
+  type SetIncrementalResponseCacheContext,
 } from '../../response-cache'
 
 import { LRUCache } from '../lru-cache'
@@ -106,12 +109,16 @@ export default class FileSystemCache implements CacheHandler {
 
   public async get(...args: Parameters<CacheHandler['get']>) {
     const [key, ctx] = args
-    const { tags, softTags, kind, isRoutePPREnabled, isFallback } = ctx
+    const { kind } = ctx
 
     let data = memoryCache?.get(key)
 
     if (this.debug) {
-      console.log('get', key, tags, kind, !!data)
+      if (kind === IncrementalCacheKind.FETCH) {
+        console.log('get', key, ctx.tags, kind, !!data)
+      } else {
+        console.log('get', key, kind, !!data)
+      }
     }
 
     // let's check the disk for seed data
@@ -157,6 +164,8 @@ export default class FileSystemCache implements CacheHandler {
         const { mtime } = await this.fs.stat(filePath)
 
         if (kind === IncrementalCacheKind.FETCH) {
+          const { tags, fetchIdx, fetchUrl } = ctx
+
           if (!this.flushToDisk) return null
 
           const lastModified = mtime.getTime()
@@ -177,8 +186,10 @@ export default class FileSystemCache implements CacheHandler {
                 console.log('tags vs storedTags mismatch', tags, storedTags)
               }
               await this.set(key, data.value, {
+                fetchCache: true,
                 tags,
-                isRoutePPREnabled,
+                fetchIdx,
+                fetchUrl,
               })
             }
           }
@@ -226,10 +237,10 @@ export default class FileSystemCache implements CacheHandler {
           }
 
           let rscData: Buffer | undefined
-          if (!isFallback) {
+          if (!ctx.isFallback) {
             rscData = await this.fs.readFile(
               this.getFilePath(
-                `${key}${isRoutePPREnabled ? RSC_PREFETCH_SUFFIX : RSC_SUFFIX}`,
+                `${key}${ctx.isRoutePPREnabled ? RSC_PREFETCH_SUFFIX : RSC_SUFFIX}`,
                 IncrementalCacheKind.APP_PAGE
               )
             )
@@ -251,7 +262,7 @@ export default class FileSystemCache implements CacheHandler {
           let meta: RouteMetadata | undefined
           let pageData: string | object = {}
 
-          if (!isFallback) {
+          if (!ctx.isFallback) {
             pageData = JSON.parse(
               await this.fs.readFile(
                 this.getFilePath(
@@ -315,7 +326,10 @@ export default class FileSystemCache implements CacheHandler {
         }
       }
     } else if (data?.value?.kind === CachedRouteKind.FETCH) {
-      const combinedTags = [...(tags || []), ...(softTags || [])]
+      const combinedTags =
+        ctx.kind === IncrementalCacheKind.FETCH
+          ? [...(ctx.tags || []), ...(ctx.softTags || [])]
+          : []
 
       const wasRevalidated = combinedTags.some((tag) => {
         if (this.revalidatedTags.includes(tag)) {
@@ -338,9 +352,11 @@ export default class FileSystemCache implements CacheHandler {
     return data ?? null
   }
 
-  public async set(...args: Parameters<CacheHandler['set']>) {
-    const [key, data, ctx] = args
-    const { isFallback } = ctx
+  public async set(
+    key: string,
+    data: IncrementalCacheValue | null,
+    ctx: SetIncrementalFetchCacheContext | SetIncrementalResponseCacheContext
+  ) {
     memoryCache?.set(key, {
       value: data,
       lastModified: Date.now(),
@@ -388,7 +404,7 @@ export default class FileSystemCache implements CacheHandler {
       writer.append(htmlPath, data.html)
 
       // Fallbacks don't generate a data file.
-      if (!isFallback) {
+      if (!ctx.fetchCache && !ctx.isFallback) {
         writer.append(
           this.getFilePath(
             `${key}${
@@ -441,7 +457,7 @@ export default class FileSystemCache implements CacheHandler {
         filePath,
         JSON.stringify({
           ...data,
-          tags: ctx.tags,
+          tags: ctx.fetchCache ? ctx.tags : [],
         })
       )
     }