Gem::Commands::UnpackCommand#execute

# File tmp/rubies/ruby-3.0.5/lib/rubygems/commands/unpack_command.rb, line 74
def execute
  security_policy = options[:security_policy]

  get_all_gem_names.each do |name|
    dependency = Gem::Dependency.new name, options[:version]
    path = get_path dependency

    unless path
      alert_error "Gem '#{name}' not installed nor fetchable."
      next
    end

    if @options[:spec]
      spec, metadata = Gem::Package.raw_spec(path, security_policy)

      if metadata.nil?
        alert_error "--spec is unsupported on '#{name}' (old format gem)"
        next
      end

      spec_file = File.basename spec.spec_file

      FileUtils.mkdir_p @options[:target] if @options[:target]

      destination = begin
        if @options[:target]
          File.join @options[:target], spec_file
        else
          spec_file
        end
      end

      File.open destination, 'w' do |io|
        io.write metadata
      end
    else
      basename = File.basename path, '.gem'
      target_dir = File.expand_path basename, options[:target]

      package = Gem::Package.new path, security_policy
      package.extract_files target_dir

      say "Unpacked gem: '#{target_dir}'"
    end
  end
end