class Gem::Source::Git

def cache # :nodoc:
  return unless @remote
  if File.exist? repo_cache_dir
    Dir.chdir repo_cache_dir do
      system git_command, "fetch", "--quiet", "--force", "--tags",
             @repository, "refs/heads/*:refs/heads/*"
    end
  else
    system git_command, "clone", "--quiet", "--bare", "--no-hardlinks",
           @repository, repo_cache_dir
  end
end