class Gem::Commands::DependencyCommand

def execute
  if options[:reverse_dependencies] and remote? and not local? then
    alert_error 'Only reverse dependencies for local gems are supported.'
    terminate_interaction 1
  end
  options[:args] << '' if options[:args].empty?
  pattern = if options[:args].length == 1 and
               options[:args].first =~ /\A\/(.*)\/(i)?\z/m then
              flags = $2 ? Regexp::IGNORECASE : nil
              Regexp.new $1, flags
            else
              /\A#{Regexp.union(*options[:args])}/
            end
  # TODO: deprecate for real damnit
  dependency = Gem::Deprecate.skip_during {
    Gem::Dependency.new pattern, options[:version]
  }
  dependency.prerelease = options[:prerelease]
  specs = []
  specs.concat dependency.matching_specs if local?
  if remote? and not options[:reverse_dependencies] then
    fetcher = Gem::SpecFetcher.fetcher
    ss, _ = fetcher.spec_for_dependency dependency
    ss.each { |s,o| specs << s }
  end
  if specs.empty? then
    patterns = options[:args].join ','
    say "No gems found matching #{patterns} (#{options[:version]})" if
      Gem.configuration.verbose
    terminate_interaction 1
  end
  specs = specs.uniq.sort
  reverse = Hash.new { |h, k| h[k] = [] }
  if options[:reverse_dependencies] then
    specs.each do |spec|
      reverse[spec.full_name] = find_reverse_dependencies spec
    end
  end
  if options[:pipe_format] then
    specs.each do |spec|
      unless spec.dependencies.empty?
        spec.dependencies.sort_by { |dep| dep.name }.each do |dep|
          say "#{dep.name} --version '#{dep.requirement}'"
        end
      end
    end
  else
    response = ''
    specs.each do |spec|
      response << print_dependencies(spec)
      unless reverse[spec.full_name].empty? then
        response << "  Used by\n"
        reverse[spec.full_name].each do |sp, dep|
          response << "    #{sp} (#{dep})\n"
        end
      end
      response << "\n"
    end
    say response
  end
end