Datamapper DataMapper

After a model is generated, its associated records do not respect the order specified in association declaration. Here is some code to demonstrate the problem:

gem 'dm-core'
gem 'dm-sweatshop'
require 'dm-core'
require 'dm-sweatshop'

class Target
  include DataMapper::Resource
  property :id, Serial
  has n, :matches, :order => [:score]
end

class Match
  include DataMapper::Resource
  property :id, Serial
  property :score, Float
  belongs_to :target
end

Match.fixture {{
  :score => rand
}}

Target.fixture {{
  :matches => 10.of {Match.gen}
}}

DataMapper.setup(:default, "sqlite3://dm_test.db")
DataMapper.auto_migrate!
target = Target.gen
scores = target.matches.map {|m| m.score}
print scores == scores.sort ? "sorted\n" : "unsorted\n"
target.reload
scores = target.matches.map {|m| m.score}
print scores == scores.sort ? "sorted\n" : "unsorted\n"

The workaround is to reload the model, but this is easy to forget to do, especially since dm-sweatshop hides the fact that the associated records were added via the "<<" operator.

On fix is to have #generate reload the model before it returns. The other fix is to generate the associations in a way that DM will not cache them:

10.times {Match.create(:target_id => target.id, :score => rand)}