# File lib/chef/provider/package/rubygems.rb, line 128
          def find_newest_remote_version(gem_dependency, *sources)
            # DependencyInstaller sorts the results such that the last one is
            # always the one it considers best.
            spec_with_source = dependency_installer.find_gems_with_sources(gem_dependency).last

            spec = spec_with_source && spec_with_source[0]
            version = spec && spec_with_source[0].version
            if version
              logger.debug { "#{@new_resource} found gem #{spec.name} version #{version} for platform #{spec.platform} from #{spec_with_source[1]}" }
              version
            else
              source_list = sources.compact.empty? ? "[#{Gem.sources.join(', ')}]" : "[#{sources.join(', ')}]"
              logger.warn { "#{@new_resource} failed to find gem #{gem_dependency} from #{source_list}" }
              nil
            end
          end