assumes serial primary keys

[alexkalderimis]

If you try to version a resource that does not user a serial primary key, you run into integrity issues due to the tight coupling between property option values and the construction of the primary key (https://github.com/datamapper/dm-is-versioned/blob/master/lib/dm-is-versioned/is/versioned.rb#L88). If a natural key is used, then the original key is ignored in the version table.

There is no method used for the consuming class to override this behaviour - this could be easily remedied by extracting the property argument creation logic to a new method that can be overrriden (https://github.com/datamapper/dm-is-versioned/blob/master/lib/dm-is-versioned/is/versioned.rb#L78-L88), eg:

module ClassMethods

  def define_version_property(property)
    type = case property
      when DataMapper::Property::Discriminator then Class
      when DataMapper::Property::Serial        then Integer
    else
      property.class
    end
    options = property.options.merge(:key => property.name == @on)
    options[:key] = true if options.delete(:serial)
    return property.name, type, options
  end

  def const_missing(name)
    if name == :Version
      model = DataMapper::Model.new(name, self)
      properties.each do |property|
        name, type, options = define_version_property property
        model.property(property.name, type, options)
      end
      model
    else
      super
    end
  end

end # ClassMethods

And then the consumer need only override define_version_property to adjust the options hash