# File lib/r10k/git/repository.rb, line 37
  def resolve_ref(pattern)
    commit   = resolve_tag(pattern)
    commit ||= resolve_remote_head(pattern)
    commit ||= resolve_head(pattern)
    commit ||= resolve_commit(pattern)

    if commit
      commit.chomp
    else
      raise R10K::Git::UnresolvableRefError.new("Could not resolve Git ref '#{ref}'", :ref => pattern, :git_dir => git_dir)
    end
  end