fix incorrect fetch cache handling (vercel#58460)

### What?
When `FetchCache` is used, cache gets were incorrectly bailing. This would result in unexpected behavior, like continuously revalidating a cache key, as described in vercel#57978.

### Why?
vercel#57902 introduced a refactor to the `FileSystemCache` and changed the interface of `get`, but this change was not propagated to `FetchCache`. Specifically, `fetchCache` was removed in favor of a new type `kindHint`. As a result, cache reads would always short circuit because `fetchCache` would never be defined.

### How?
This updates the interface on `FetchCache` to match what is defined on the base `CacheHandler`. I've also updated the args to both `get` and `set` to be derived from `CacheHandler` so we don't have any type inconsistencies in the future.

I will be following up with a test in the CLI repo to test against a deployed app (since minimalMode cannot be easily mocked in our test suite). Manually verified these changes against the repro in the original issue below, at the following URLs:

https://revalidate-vercel-test-iota.vercel.app/fetch-cache-test
https://revalidate-vercel-test-iota.vercel.app/revalidate-tag-test

Fixes vercel#57978
Fixes vercel#58306

packages/next/src/server/lib/incremental-cache/fetch-cache.ts

@@ -142,19 +142,13 @@ export default class FetchCache implements CacheHandler {
     }
   }
 
-  public async get(
-    key: string,
-    ctx: {
-      tags?: string[]
-      softTags?: string[]
-      fetchCache?: boolean
-      fetchUrl?: string
-      fetchIdx?: number
-    }
-  ) {
-    const { tags, softTags, fetchCache, fetchIdx, fetchUrl } = ctx
+  public async get(...args: Parameters<CacheHandler['get']>) {
+    const [key, ctx = {}] = args
+    const { tags, softTags, kindHint, fetchIdx, fetchUrl } = ctx
 
-    if (!fetchCache) return null
+    if (kindHint !== 'fetch') {
+      return null
+    }
 
     if (Date.now() < rateLimitedUntil) {
       if (this.debug) {
@@ -262,21 +256,9 @@ export default class FetchCache implements CacheHandler {
     return data || null
   }
 
-  public async set(
-    key: string,
-    data: CacheHandlerValue['value'],
-    {
-      fetchCache,
-      fetchIdx,
-      fetchUrl,
-      tags,
-    }: {
-      tags?: string[]
-      fetchCache?: boolean
-      fetchUrl?: string
-      fetchIdx?: number
-    }
-  ) {
+  public async set(...args: Parameters<CacheHandler['set']>) {
+    const [key, data, ctx] = args
+    const { fetchCache, fetchIdx, fetchUrl, tags } = ctx
     if (!fetchCache) return
 
     if (Date.now() < rateLimitedUntil) {

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

@@ -1,10 +1,7 @@
 import type { RouteMetadata } from '../../../export/routes/types'
 import type { CacheHandler, CacheHandlerContext, CacheHandlerValue } from './'
 import type { CacheFs } from '../../../shared/lib/utils'
-import type {
-  CachedFetchValue,
-  IncrementalCacheKindHint,
-} from '../../response-cache'
+import type { CachedFetchValue } from '../../response-cache'
 
 import LRUCache from 'next/dist/compiled/lru-cache'
 import path from '../../../shared/lib/isomorphic/path'
@@ -120,18 +117,9 @@ export default class FileSystemCache implements CacheHandler {
     }
   }
 
-  public async get(
-    key: string,
-    {
-      tags,
-      softTags,
-      kindHint,
-    }: {
-      tags?: string[]
-      softTags?: string[]
-      kindHint?: IncrementalCacheKindHint
-    } = {}
-  ) {
+  public async get(...args: Parameters<CacheHandler['get']>) {
+    const [key, ctx = {}] = args
+    const { tags, softTags, kindHint } = ctx
     let data = memoryCache?.get(key)
 
     // let's check the disk for seed data
@@ -302,13 +290,8 @@ export default class FileSystemCache implements CacheHandler {
     return data ?? null
   }
 
-  public async set(
-    key: string,
-    data: CacheHandlerValue['value'],
-    ctx: {
-      tags?: string[]
-    }
-  ) {
+  public async set(...args: Parameters<CacheHandler['set']>) {
+    const [key, data, ctx] = args
     memoryCache?.set(key, {
       value: data,
       lastModified: Date.now(),