Eager load of "variants_including_master" doesn't affect "master" access

[crashtech]

solidus/core/app/models/spree/product.rb

Line 34 in 2b69316

has_one :master,

Since the master method is direct connected to the association, there's no way take advantage of the eager loading. Which means:

product = Spree::Product.includes(:variants_including_master).first
master = product.master # This will perform another query

The solution is pretty easy, I just don't have the time to read and follow the collaboration guidelines.

# On core/app/models/spree/product.rb
def master
  return super unless variants_including_master.loaded?
  variants_including_master.find(&:is_master?)
end

[jhawthorn]

I don't want to do this because if will cause strange behaviour.

For example, the master association is autosave: true, but variants_including_master is not. So master is only autosaved if variants_including_master isn't loaded first.

Also if master is modified but not saved and then variants_including_master loaded loaded, those modifications will no longer be visible.