Datamapper DataMapper

Greetings,

I have the following models, and I am using dm-is-list to sort them:

    class Section
        include DataMapper::Resource
        
        property :id, Serial
        property :name, String, :length => 1..100
        property :credits, String, :length => 1..10
    
        has n, :courses, :through => Resource
    
        is :list, :scope => [:program_id]
    end
    
    class Course
        include DataMapper::Resource
    
        property :id, Serial
        property :subj, String, :length => 4
        property :code, String, :length => 3..5
        property :name, String, :length => 1..100
        property :description, Text
        property :credits, String, :length => 1..10
    
        has n, :sections, :through => Resource
    end

    class CourseSection
        include DataMapper::Resource
    
        belongs_to :course, :key => true
        belongs_to :section, :key => true
    
        is :list, :scope => [:section_id]
    end

I am unable to select a given course and move it, so I am moving the Course Sections. I can use CourseSection.move(position) without issue. My problem gets more complicated when I try to use move_to_list(sectionID, position).

dm-is-list is setting the position value to NULL (I have verified that position is being sent). I have even tried to use move_to_list(sectionID, 100), an explicitly set position, and move_to_list(sectionID) with no position, and NULL is still saved to the database. Obviously, subsequent attempts to move the item after that fail.

I attempted to define the position property explicitly as not null but that just resulted in an error when it tried to save the null. Position should never be null. This is making the gem unusable for me at this time.

The specific error received is:

undefined method `-' for nil:NilClass
file: list.rb location: move_without_saving line: 591

or

undefined method `+' for nil:NilClass
file: list.rb location: move_without_saving line: 545