code: public function autoLogin(EntityInterface $user): ?Response
      {
          $controller = $this->getController();
          $request = $controller->request;
          $token = $request->getQuery('t');
          if (empty($token)) {
              return null;
          }
  
          $this->Auth->logout();
          $tokenData = $user->validateLoginToken($token, $user->getKey(), $user->getSalt());
          if (!is_array($tokenData)) {
              return null;
          }
          if (!empty($tokenData['addRememberMeCookie']) && $tokenData['addRememberMeCookie']) {
              $this->addRememberMeCookie((string)$user->id);
          }
          $userData = $user->toArray();
          $userData['user'] = $user;
          $this->Auth->setUser($userData);
          if (!empty($tokenData['url'])) {
              return $controller->redirect($tokenData['url']);
          }
  
          return $controller->redirect($this->getConfig('defaultRedirect'));
      }
docs: Attempts to auto login a user and returns a redirect on success.
  
  @param \Cake\Datasource\EntityInterface $user User
  @return \Cake\Http\Response|null