class ChefCLI::Command::Diff

def parse_git_comparison(git_ref)
  if git_ref.include?("...")
    old_ref, new_ref, *extra = git_ref.split("...")
    @old_base, @new_base = [old_ref, new_ref].map do |r|
      Policyfile::ComparisonBase::Git.new(r, policyfile_lock_relpath)
    end
    unless extra.empty?
      ui.err("Unable to parse git comparison `#{git_ref}`. Only 2 references can be specified.")
      return false
    end
  else
    @old_base = Policyfile::ComparisonBase::Git.new(git_ref, policyfile_lock_relpath)
    @new_base = Policyfile::ComparisonBase::Local.new(policyfile_lock_relpath)
  end
  true
end