class Bundler::Source::Git::GitProxy

def checkout
  return if path.exist? && has_revision_cached?
  extra_ref = "#{ref}:#{ref}" if ref && ref.start_with?("refs/")
  Bundler.ui.info "Fetching #{URICredentialsFilter.credential_filtered_uri(uri)}"
  configured_uri = configured_uri_for(uri).to_s
  unless path.exist?
    SharedHelpers.filesystem_access(path.dirname) do |p|
      FileUtils.mkdir_p(p)
    end
    git_retry "clone", configured_uri, path.to_s, "--bare", "--no-hardlinks", "--quiet"
    return unless extra_ref
  end
  with_path do
    git_retry(*["fetch", "--force", "--quiet", "--tags", configured_uri, "refs/heads/*:refs/heads/*", extra_ref].compact, :dir => path)
  end
end