feat(cache): add cache-mode client behavior (read-denied warning + ACTIONS_CACHE_MODE skip) (#2447)

* feat(cache): surface cache read-denied as a distinct restore warning

Mirror the existing cache write-denied handling on the restore path. When
the receiver refuses a download URL because the run's token has no readable
cache scopes, it returns a twirp PermissionDenied (HTTP 403). The twirp
client wraps that 403 in a generic Error, so the stable 'cache read denied:'
prefix is embedded in the message rather than at the start.

- Add CACHE_READ_DENIED_PREFIX and CacheReadDeniedError
- Dispatch on the prefix in the restoreCacheV2 catch block (V2 only), log a
  policy-specific warning, and report a cache miss so the run continues
- Add a test mirroring the write-denied coverage

* chore(cache): trim comments, bump to 6.2.0, add RELEASES entry

* refactor(cache): dispatch read-denied by error name to mirror write path

Re-throw CacheReadDeniedError from an inner try/catch around
GetCacheEntryDownloadURL and dispatch on typedError.name in the outer catch,
matching how saveCacheV2 handles CacheWriteDeniedError.

* feat(cache): handle read-denied on the v1 restore path

Extend the read-denied handling to Cache Service v1 so GHES (which forces v1
via _apis/artifactcache) is covered when read-scope enforcement ships there.

- Surface the receiver's error body message from getCacheEntry instead of a
  generic status-code error, so the cache read denied: prefix reaches callers
- Re-throw CacheReadDeniedError from restoreCacheV1 and dispatch on it in the
  outer catch, mirroring restoreCacheV2 and the write-denied v1 handling
- Add a v1 read-denied test

* refactor(cache): only surface receiver body for read-denied on v1

* test(cache): assert getCacheEntry only surfaces body for read-denied

* test(cache): cover non-read-denied getCacheEntry passthrough on v1

* refactor(cache): share read-denied prefix via constants to avoid drift

* feat(cache): skip restore/save per ACTIONS_CACHE_MODE

* test(cache): expand ACTIONS_CACHE_MODE skip coverage across v1/v2 and unknown modes

* fix copilot pr feedback

Co-authored-by: Copilot Autofix powered by AI <[email protected]>

* docs(cache): remove internal reference from cache-mode comment

* test(cache): merge redundant cache-mode skip tests and simplify read-denied handling

Address PR review feedback:
- Merge the duplicate restore/save skip test.each blocks into single blocks parametrized over ACTIONS_CACHE_SERVICE_V2.
- Drop the redundant CacheReadDeniedError catch arms; the typed error is not an HttpClientError so it already falls through to a non-fatal warning.
- Clarify why read-denied classification happens both in getCacheEntry and cache.ts (dependency-free internal module cannot import the typed error).

* refactor(cache): drop redundant CacheWriteDeniedError catch arms

Mirror the read-denied simplification on the save path. CacheWriteDeniedError
is not an HttpClientError and its name does not match the ReserveCacheError
arm, so it falls through to the same non-fatal warning. Logging behavior is
unchanged (warns, never fails the run) and the exported type is still thrown
internally for consumers and tests. Also refresh stale doc wording.

* test(cache): collapse redundant restore getCacheEntry-failure tests

The two restoreCache tests exercised the identical warning + cache-miss path
now that read-denied is no longer reclassified in the catch, so merge them into
one. The read-denied prefix detection that actually branches on the message is
covered by getCacheEntry tests in cacheHttpClient.test.ts.

---------

Co-authored-by: Copilot Autofix powered by AI <[email protected]>

packages/cache/__tests__/cacheHttpClient.test.ts

@@ -1,8 +1,10 @@
-import {downloadCache} from '../src/internal/cacheHttpClient'
+import {downloadCache, getCacheEntry} from '../src/internal/cacheHttpClient'
 import {getCacheVersion} from '../src/internal/cacheUtils'
 import {CompressionMethod} from '../src/internal/constants'
 import * as downloadUtils from '../src/internal/downloadUtils'
+import * as requestUtils from '../src/internal/requestUtils'
 import {DownloadOptions, getDownloadOptions} from '../src/options'
+import {HttpClientError} from '@actions/http-client'
 
 jest.mock('../src/internal/downloadUtils')
 
@@ -57,6 +59,37 @@ test('getCacheVersion with enableCrossOsArchive as false returns version on wind
   }
 })
 
+test('getCacheEntry throws a generic status-code error for non-read-denied failures', async () => {
+  // Regression: a non read-denied failure must NOT leak the server's body
+  // message; it should surface the generic status-code error.
+  jest.spyOn(requestUtils, 'retryTypedResponse').mockResolvedValue({
+    statusCode: 403,
+    result: null,
+    headers: {},
+    error: new HttpClientError('some other server detail', 403)
+  })
+
+  await expect(getCacheEntry(['key'], ['node_modules'])).rejects.toThrow(
+    'Cache service responded with 403'
+  )
+})
+
+test('getCacheEntry surfaces the body message for a cache read denial', async () => {
+  jest.spyOn(requestUtils, 'retryTypedResponse').mockResolvedValue({
+    statusCode: 403,
+    result: null,
+    headers: {},
+    error: new HttpClientError(
+      'cache read denied: token has no readable scopes',
+      403
+    )
+  })
+
+  await expect(getCacheEntry(['key'], ['node_modules'])).rejects.toThrow(
+    'cache read denied: token has no readable scopes'
+  )
+})
+
 test('downloadCache uses http-client for non-Azure URLs', async () => {
   const downloadCacheHttpClientMock = jest.spyOn(
     downloadUtils,