build_configs

# File activerecord/lib/active_record/database_configurations.rb, line 200
      def build_configs(configs)
        return configs.configurations if configs.is_a?(DatabaseConfigurations)
        return configs if configs.is_a?(Array)

        db_configs = configs.flat_map do |env_name, config|
          if config.is_a?(Hash) && config.values.all?(Hash)
            walk_configs(env_name.to_s, config)
          else
            build_db_config_from_raw_config(env_name.to_s, "primary", config)
          end
        end

        unless db_configs.find(&:for_current_env?)
          db_configs << environment_url_config(default_env, "primary", {})
        end

        merge_db_environment_variables(default_env, db_configs.compact)
      end