fix(client): do not cache credentialFuncs for unconfigured repositories

When we create the http client for a given repository the code checks if it is somehow configured.
It caches a function called `credentialFunction`. This function knows how to retrieve the
credentials for a given repository. For unconfigured repositories, or repositories that fail to
get valid credentials using their `credentialFunction,` we cache an `emptyCredential function`.
This causes trouble in case of transient errors causing the client to not recover.
This commit avoids caching the `emptyCredential function` in such cases or for unconfigured repositories.

Signed-off-by: Aldo Lacuku <[email protected]>

pkg/oci/authn/client.go

@@ -91,8 +91,7 @@ func NewClient(options ...func(*Options)) *auth.Client {
 					return cred, nil
 				}
 			}
-			// remember empty cred func for registries we dont have creds for
-			opt.CredentialsFuncsCache[reg] = EmptyCredentialFunc
+
 			return auth.EmptyCredential, nil
 		},
 	}