fix: GCA creds loading order (#6498)

packages/core/src/code_assist/oauth2.ts

@@ -351,27 +351,32 @@ export function getAvailablePort(): Promise<number> {
 }
 
 async function loadCachedCredentials(client: OAuth2Client): Promise<boolean> {
-  try {
-    const keyFile =
-      process.env['GOOGLE_APPLICATION_CREDENTIALS'] ||
-      getCachedCredentialPath();
+  const pathsToTry = [
+    getCachedCredentialPath(),
+    process.env['GOOGLE_APPLICATION_CREDENTIALS'],
+  ].filter((p): p is string => !!p);
 
-    const creds = await fs.readFile(keyFile, 'utf-8');
-    client.setCredentials(JSON.parse(creds));
+  for (const keyFile of pathsToTry) {
+    try {
+      const creds = await fs.readFile(keyFile, 'utf-8');
+      client.setCredentials(JSON.parse(creds));
 
-    // This will verify locally that the credentials look good.
-    const { token } = await client.getAccessToken();
-    if (!token) {
-      return false;
+      // This will verify locally that the credentials look good.
+      const { token } = await client.getAccessToken();
+      if (!token) {
+        continue;
+      }
+
+      // This will check with the server to see if it hasn't been revoked.
+      await client.getTokenInfo(token);
+
+      return true;
+    } catch (_) {
+      // Ignore and try next path.
     }
-
-    // This will check with the server to see if it hasn't been revoked.
-    await client.getTokenInfo(token);
-
-    return true;
-  } catch (_) {
-    return false;
   }
+
+  return false;
 }
 
 async function cacheCredentials(credentials: Credentials) {