Rails3.1 + Ruby2.0 with Sprockets

sprockets_ext.rb

# Rails 3.2.13以前のバージョン + Ruby2.0の組み合わせだと適切にDirectiveをパースできない不具合がある
# ref: https://github.com/sstephenson/sprockets/issues/352
directive_pattern = /
  ^ \W* = \s* (\w+.*?) (\*\/)? $
/x
Sprockets::DirectiveProcessor.class_eval do
  remove_const(:DIRECTIVE_PATTERN)
  const_set(:DIRECTIVE_PATTERN, directive_pattern)

  def directives
    @directives ||= header.lines.each_with_index.map { |line, index|
      if directive = line[Sprockets::DirectiveProcessor::DIRECTIVE_PATTERN, 1]
        name, *args = Shellwords.shellwords(directive)
        # 2.0系からprivateメソッドのrespond_to?には第2引数が必要になった
        if respond_to?("process_#{name}_directive", true)
          [index + 1, name, *args]
        end
      end
    }.compact
  end
end