    # File lib/chef/provider/package/rubygems.rb, line 129
              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