message: Fix eval_metrics json to correctly accept the default
diff: @@ -139,8 +139,8 @@ SolverParser::SolverParser(const std::string& file)
  {"AUC", metrics::Type::AUC}
  };
  + if (has_key_(j, "eval_metrics")) {
  auto eval_metrics = get_json(j, "eval_metrics");
  - if (!eval_metrics.empty()) {
  if (eval_metrics.is_array()) {
  for(auto metric: eval_metrics) {
  std::stringstream ss(metric.get<std::string>());
  @@ -182,6 +182,7 @@ SolverParser::SolverParser(const std::string& file)
  }
  else {
  // Default is AUC without the threshold
  + MESSAGE_("Default evaluation metric is AUC without threshold value");
  metrics_spec[metrics::Type::AUC] = 1.f;
  }
  