# File lib/bundler/dsl.rb, line 132
    def git_source(name, &block)
      unless block_given?
        raise InvalidOption, "You need to pass a block to #git_source"
      end

      if valid_keys.include?(name.to_s)
        raise InvalidOption, "You cannot use #{name} as a git source. It " \
          "is a reserved key. Reserved keys are: #{valid_keys.join(", ")}"
      end

      @git_sources[name.to_s] = block
    end