class Gem::Specification

def reset_nil_attributes_to_default
  nil_attributes = self.class.non_nil_attributes.find_all do |name|
    !instance_variable_defined?("@#{name}") || instance_variable_get("@#{name}").nil?
  end
  nil_attributes.each do |attribute|
    default = self.default_value attribute
    value = case default
            when Time, Numeric, Symbol, true, false, nil then default
            else default.dup
            end
    instance_variable_set "@#{attribute}", value
  end
  @installed_by_version ||= nil
end