fix: allow re-auth with another google account (#6544)

packages/core/src/code_assist/oauth2.ts

@@ -391,13 +391,19 @@ function getCachedCredentialPath(): string {
   return path.join(os.homedir(), GEMINI_DIR, CREDENTIAL_FILENAME);
 }
 
+export function clearOauthClientCache() {
+  oauthClientPromises.clear();
+}
+
 export async function clearCachedCredentialFile() {
   try {
     await fs.rm(getCachedCredentialPath(), { force: true });
     // Clear the Google Account ID cache when credentials are cleared
     await clearCachedGoogleAccount();
-  } catch (_) {
-    /* empty */
+    // Clear the in-memory OAuth client cache to force re-authentication
+    clearOauthClientCache();
+  } catch (e) {
+    console.error('Failed to clear cached credentials:', e);
   }
 }