Only warn when there are no authentications (#671)

This fixes an issue where a warning message would be printed on systems
using ADC from the metadata server.

Fixes #670

Author: sethvargo

dist/index.js

@@ -21,6 +21,7 @@ import {
   bestVersion,
   installComponent,
   installGcloudSDK,
+  isAuthenticated,
   setProject,
 } from '@google-github-actions/setup-cloud-sdk';
 import {
@@ -102,9 +103,10 @@ export async function run(): Promise<void> {
     if (credFile) {
       await authenticateGcloudSDK(credFile);
       core.info('Successfully authenticated');
-    } else {
+    } else if (!(await isAuthenticated())) {
       core.warning(
-        'No authentication found for gcloud, authenticate with `google-github-actions/auth`.',
+        `The gcloud CLI is not authenticated. Authenticate by adding the ` +
+          `"google-github-actions/auth" step prior this one.`,
       );
     }
 

src/main.ts

@@ -64,6 +64,7 @@ const defaultMocks = (
     }),
 
     authenticateGcloudSDK: m.method(setupGcloud, 'authenticateGcloudSDK', () => {}),
+    isAuthenticated: m.method(setupGcloud, 'isAuthenticated', () => {}),
     isInstalled: m.method(setupGcloud, 'isInstalled', () => {
       return true;
     }),