search_up

# File lib/bundler/shared_helpers.rb, line 270
    def search_up(*names)
      previous = nil
      current  = File.expand_path(SharedHelpers.pwd).untaint

      until !File.directory?(current) || current == previous
        if ENV["BUNDLE_SPEC_RUN"]
          # avoid stepping above the tmp directory when testing
          gemspec = if ENV["BUNDLE_RUBY"] && ENV["BUNDLE_GEM"]
            # for Ruby Core
            "lib/bundler.gemspec"
          else
            "bundler.gemspec"
          end

          # avoid stepping above the tmp directory when testing
          return nil if File.file?(File.join(current, gemspec))
        end

        names.each do |name|
          filename = File.join(current, name)
          yield filename
        end
        previous = current
        current = File.expand_path("..", current)
      end
    end