后台首页未登录时不提示错误直接跳转登录页面

@@ -139,6 +139,10 @@ class Backend extends Controller
                 Hook::listen('admin_nologin', $this);
                 $url = Session::get('referer');
                 $url = $url ? $url : $this->request->url();
+                if ($url == '/') {
+                    $this->redirect('index/login', [], 302, ['referer' => $url]);
+                    exit;
+                }
                 $this->error(__('Please login first'), url('index/login', ['url' => $url]));
             }
             // 判断是否需要验证权限