class Gem::Specification

def git_version
  if @loaded_from && File.exist?(File.join(full_gem_path, ".git"))
    sha = Dir.chdir(full_gem_path){ `git rev-parse HEAD`.strip }
    branch = full_gem_path.split("-")[3]
    (branch && branch != sha) ? " #{branch}-#{sha[0...6]}" : " #{sha[0...6]}"
  end
end