message: bugfix SRandmemberCmd::Do()
diff: @@ -422,7 +422,7 @@ void SRandmemberCmd::Do() {
  std::vector<std::string> members;
  nemo::Status s = g_pika_server->db()->SRandMember(key_, members, count_);
  if (s.ok() || s.IsNotFound()) {
  - if (!reply_arr) {
  + if (!reply_arr && members.size()) {
  res_.AppendStringLen(members[0].size());
  res_.AppendContent(members[0]);
  } else {
  