Perform variant override scoping on product/variant by external class. Centralise this so we can load everything in one go.

app/controllers/shop_controller.rb

@@ -46,10 +46,12 @@ class ShopController < BaseController
 
   def products_for_shop
     if current_order_cycle
+      scoper = OpenFoodNetwork::ScopeProductToHub.new(current_distributor)
+
       current_order_cycle.
         valid_products_distributed_by(current_distributor).
         order(taxon_order).
-        each { |p| p.scope_to_hub current_distributor }.
+        each { |p| scoper.scope(p) }.
         select { |p| !p.deleted? && p.has_stock_for_distribution?(current_order_cycle, current_distributor) }
     end
   end
@@ -69,9 +71,10 @@ class ShopController < BaseController
     # We use the in_stock? method here instead of the in_stock scope because we need to
     # look up the stock as overridden by VariantOverrides, and the scope method is not affected
     # by them.
+    scoper = OpenFoodNetwork::ScopeVariantToHub.new(current_distributor)
     Spree::Variant.
       for_distribution(current_order_cycle, current_distributor).
-      each { |v| v.scope_to_hub current_distributor }.
+      each { |v| scoper.scope(v) }.
       select(&:in_stock?)
   end
 

app/controllers/spree/admin/variants_controller_decorator.rb

@@ -14,9 +14,10 @@ Spree::Admin::VariantsController.class_eval do
     if params[:distributor_id].present?
       distributor = Enterprise.find params[:distributor_id]
       @variants = @variants.in_distributor(distributor)
+      scoper = OpenFoodNetwork::ScopeVariantToHub.new(distributor)
       # Perform scoping after all filtering is done.
       # Filtering could be a problem on scoped variants.
-      @variants.each { |v| v.scope_to_hub(distributor) }
+      @variants.each { |v| scoper.scope(v) }
     end
   end
 

app/models/spree/inventory_unit_decorator.rb

@@ -4,9 +4,10 @@ module Spree
       return [] unless order.completed?
 
       #increase inventory to meet initial requirements
+      scoper = OpenFoodNetwork::ScopeVariantToHub.new(order.distributor)
       order.line_items.each do |line_item|
         # Scope variant to hub so that stock levels may be subtracted from VariantOverride.
-        line_item.variant.scope_to_hub order.distributor
+        scoper.scope(line_item.variant)
 
         increase(order, line_item.variant, line_item.quantity)
       end

app/models/spree/order_populator_decorator.rb

@@ -9,7 +9,7 @@ Spree::OrderPopulator.class_eval do
       errors.add(:base, "That distributor or order cycle can't supply all the products in your cart. Please choose another.")
     end
 
-    if valid? 
+    if valid?
       @order.with_lock do
         @order.empty! if overwrite
 
@@ -33,7 +33,7 @@ Spree::OrderPopulator.class_eval do
   def attempt_cart_add(variant_id, quantity, max_quantity = nil)
     quantity = quantity.to_i
     variant = Spree::Variant.find(variant_id)
-    variant.scope_to_hub @distributor
+    OpenFoodNetwork::ScopeVariantToHub.new(@distributor).scope(variant)
     if quantity > 0
       if check_stock_levels(variant, quantity) &&
           check_order_cycle_provided_for(variant) &&

app/models/spree/product_decorator.rb

@@ -1,8 +1,4 @@
-require 'open_food_network/scope_product_to_hub'
-
 Spree::Product.class_eval do
-  include OpenFoodNetwork::ProductScopableToHub
-
   # We have an after_destroy callback on Spree::ProductOptionType. However, if we
   # don't specify dependent => destroy on this association, it is not called. See:
   # https://github.com/rails/rails/issues/7618

app/models/spree/variant_decorator.rb

@@ -1,10 +1,7 @@
-require 'open_food_network/scope_variant_to_hub'
 require 'open_food_network/enterprise_fee_calculator'
 require 'open_food_network/option_value_namer'
 
 Spree::Variant.class_eval do
-  include OpenFoodNetwork::VariantScopableToHub
-
   has_many :exchange_variants, dependent: :destroy
   has_many :exchanges, through: :exchange_variants
   has_many :variant_overrides

lib/open_food_network/scope_product_to_hub.rb

@@ -1,16 +1,21 @@
 require 'open_food_network/scope_variant_to_hub'
 
 module OpenFoodNetwork
-  module ScopeProductToHub
-    def variants_distributed_by(order_cycle, distributor)
-      super.each { |v| v.scope_to_hub @hub }
-    end
-  end
-
-  module ProductScopableToHub
-    def scope_to_hub(hub)
-      extend OpenFoodNetwork::ScopeProductToHub
+  class ScopeProductToHub
+    def initialize(hub)
       @hub = hub
     end
+
+    def scope(product)
+      product.send :extend, OpenFoodNetwork::ScopeProductToHub::ScopeProductToHub
+      product.instance_variable_set :@hub, @hub
+    end
+
+
+    module ScopeProductToHub
+      def variants_distributed_by(order_cycle, distributor)
+        super.each { |v| ScopeVariantToHub.new(@hub).scope(v) }
+      end
+    end
   end
 end

lib/open_food_network/scope_variant_to_hub.rb

@@ -1,30 +1,36 @@
 module OpenFoodNetwork
-  module ScopeVariantToHub
-    def price
-      VariantOverride.price_for(@hub, self) || super
-    end
-
-    def price_in(currency)
-      Spree::Price.new(amount: price, currency: currency)
-    end
-
-    def count_on_hand
-      VariantOverride.count_on_hand_for(@hub, self) || super
-    end
-
-    def decrement!(attribute, by=1)
-      if attribute == :count_on_hand && VariantOverride.stock_overridden?(@hub, self)
-        VariantOverride.decrement_stock! @hub, self, by
-      else
-        super
-      end
-    end
-  end
-
-  module VariantScopableToHub
-    def scope_to_hub(hub)
-      extend OpenFoodNetwork::ScopeVariantToHub
+  class ScopeVariantToHub
+    def initialize(hub)
       @hub = hub
     end
+
+    def scope(variant)
+      variant.send :extend, OpenFoodNetwork::ScopeVariantToHub::ScopeVariantToHub
+      variant.instance_variable_set :@hub, @hub
+    end
+
+
+    module ScopeVariantToHub
+      def price
+        VariantOverride.price_for(@hub, self) || super
+      end
+
+      def price_in(currency)
+        Spree::Price.new(amount: price, currency: currency)
+      end
+
+      def count_on_hand
+        VariantOverride.count_on_hand_for(@hub, self) || super
+      end
+
+      def decrement!(attribute, by=1)
+        if attribute == :count_on_hand && VariantOverride.stock_overridden?(@hub, self)
+          VariantOverride.decrement_stock! @hub, self, by
+        else
+          super
+        end
+      end
+    end
+
   end
 end

lib/spree/core/controller_helpers/order_decorator.rb

@@ -3,8 +3,9 @@ Spree::Core::ControllerHelpers::Order.class_eval do
     order = current_order_without_scoped_variants(create_order_if_necessary)
 
     if order
+      scoper = OpenFoodNetwork::ScopeVariantToHub.new(order.distributor)
       order.line_items.each do |li|
-        li.variant.scope_to_hub order.distributor
+        scoper.scope(li.variant)
       end
     end
 

spec/lib/open_food_network/scope_variant_to_hub_spec.rb

@@ -5,16 +5,17 @@ module OpenFoodNetwork
     let(:hub) { create(:distributor_enterprise) }
     let(:v)   { create(:variant, price: 11.11, count_on_hand: 1) }
     let(:vo)  { create(:variant_override, hub: hub, variant: v, price: 22.22, count_on_hand: 2) }
+    let(:scoper) { ScopeVariantToHub.new(hub) }
 
     describe "overriding price" do
       it "returns the overridden price when one is present" do
         vo
-        v.scope_to_hub hub
+        scoper.scope v
         v.price.should == 22.22
       end
 
       it "returns the variant's price otherwise" do
-        v.scope_to_hub hub
+        scoper.scope v
         v.price.should == 11.11
       end
     end
@@ -22,12 +23,12 @@ module OpenFoodNetwork
     describe "overriding price_in" do
       it "returns the overridden price when one is present" do
         vo
-        v.scope_to_hub hub
+        scoper.scope v
         v.price_in('AUD').amount.should == 22.22
       end
 
       it "returns the variant's price otherwise" do
-        v.scope_to_hub hub
+        scoper.scope v
         v.price_in('AUD').amount.should == 11.11
       end
     end
@@ -35,12 +36,12 @@ module OpenFoodNetwork
     describe "overriding stock levels" do
       it "returns the overridden stock level when one is present" do
         vo
-        v.scope_to_hub hub
+        scoper.scope v
         v.count_on_hand.should == 2
       end
 
       it "returns the variant's stock level otherwise" do
-        v.scope_to_hub hub
+        scoper.scope v
         v.count_on_hand.should == 1
       end
     end

spec/models/spree/order_populator_spec.rb

@@ -21,7 +21,7 @@ module Spree
         op.populate(params).should be_false
         op.errors.to_a.should == ["That distributor or order cycle can't supply all the products in your cart. Please choose another."]
       end
-      
+
       it "empties the order if override is true" do
         op.stub(:distribution_can_supply_products_in_cart).and_return true
         order.stub(:with_lock).and_yield
@@ -38,7 +38,7 @@ module Spree
       it "attempts cart add with max_quantity" do
         op.stub(:distribution_can_supply_products_in_cart).and_return true
         order.should_receive(:empty!)
-        params = {variants: {"1" => {quantity: 1, max_quantity: 2}}} 
+        params = {variants: {"1" => {quantity: 1, max_quantity: 2}}}
         order.stub(:with_lock).and_yield
         op.should_receive(:attempt_cart_add).with("1", 1, 2).and_return true
         op.populate(params, true)
@@ -48,7 +48,6 @@ module Spree
     describe "attempt_cart_add" do
       it "performs additional validations" do
         variant = double(:variant)
-        variant.stub(:scope_to_hub)
         quantity = 123
         Spree::Variant.stub(:find).and_return(variant)