Replace validates_associated on master with current spree method for error reporting master saves

app/models/spree/product_decorator.rb

@@ -21,7 +21,6 @@ Spree::Product.class_eval do
   attr_accessible :supplier_id, :primary_taxon_id, :distributor_ids, :product_distributions_attributes, :group_buy, :group_buy_unit_size
   attr_accessible :variant_unit, :variant_unit_scale, :variant_unit_name, :unit_value, :unit_description, :notes, :images_attributes, :display_as
 
-  validates_associated :master, message: "^Price and On Hand must be valid"
   validates_presence_of :supplier
   validates :primary_taxon, presence: { message: "^Product Category can't be blank" }
   validates :tax_category_id, presence: { message: "^Tax Category can't be blank" }, if: "Spree::Config.products_require_tax_category"
@@ -212,4 +211,23 @@ Spree::Product.class_eval do
     variant.is_master = false
     self.variants << variant
   end
+
+  # Override Spree's old save_master method and replace it with the most recent method from spree repository
+  # This fixes any problems arising from failing master saves, without the need for a validates_associated on
+  # master, while giving us more specific errors as to why saving failed
+  def save_master
+    begin
+      if master && (master.changed? || master.new_record? || (master.default_price && (master.default_price.changed? || master.default_price.new_record?)))
+        master.save!
+      end
+
+    # If the master cannot be saved, the Product object will get its errors
+    # and will be destroyed
+    rescue ActiveRecord::RecordInvalid
+      master.errors.each do |att, error|
+        self.errors.add(att, error)
+      end
+      raise
+    end
+  end
 end

spec/models/spree/product_spec.rb

@@ -25,9 +25,10 @@ module Spree
       it "does not save when master is invalid" do
         s = create(:supplier_enterprise)
         t = create(:taxon)
-        product = Product.new supplier_id: s.id, name: "Apples", price: 1, primary_taxon_id: t.id
+        product = Product.new supplier_id: s.id, name: "Apples", price: 1, primary_taxon_id: t.id, variant_unit: "weight", variant_unit_scale: 1000, unit_value: 1
         product.on_hand = "10,000"
-        product.save.should be_false
+        expect(product.save).to be_false
+        expect(product.errors[:count_on_hand]).to include "is not a number"
       end
 
       it "defaults available_on to now" do