fix(fetch-cache): add check for updated tags when checking same cache key

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

@@ -168,8 +168,17 @@ export default class FetchCache implements CacheHandler {
     // on successive requests
     let data = memoryCache?.get(key)
 
-    // get data from fetch cache
-    if (!data && this.cacheEndpoint) {
+    const isCacheable = !data && this.cacheEndpoint
+    const hasFetchKindAndIncludesAllTags = tags?.every((tag) => {
+      if (data?.value?.kind !== 'FETCH') {
+        return false
+      }
+      return data.value.tags?.includes(tag)
+    })
+
+    // Get data from fetch cache. Also check if new tags have been
+    // specified with the same cache key (fetch URL)
+    if (isCacheable || !hasFetchKindAndIncludesAllTags) {
       try {
         const start = Date.now()
         const fetchParams: NextFetchCacheParams = {
@@ -220,6 +229,11 @@ export default class FetchCache implements CacheHandler {
           throw new Error(`invalid cache value`)
         }
 
+        // if new tags were specified, merge those tags to the existing tags
+        if (cached.kind === 'FETCH') {
+          cached.tags = [...new Set([...(cached.tags ?? []), ...(tags ?? [])])]
+        }
+
         const cacheState = res.headers.get(CACHE_STATE_HEADER)
         const age = res.headers.get('age')