app/models/coupon.rb in spree-0.9.4 vs app/models/coupon.rb in spree-0.10.0.beta

@@ -1,24 +1,26 @@
 class Coupon < ActiveRecord::Base
-  has_many  :credits,    :as => :adjustment_source
+  has_many  :coupon_credits,    :as => :adjustment_source
   has_calculator
+  alias credits coupon_credits
 
   validates_presence_of :code
   
   def eligible?(order)
     return false if expires_at and Time.now > expires_at
-    return false if usage_limit and credits.count >= usage_limit
+    return false if usage_limit and coupon_credits.with_order.count >= usage_limit
     return false if starts_at and Time.now < starts_at
     # TODO - also check items in the order (once we support product groups for coupons)
     true
   end
     
   def create_discount(order)
-    if eligible?(order) and amount = calculator.compute(order)
+    return if order.coupon_credits.reload.detect { |credit| credit.adjustment_source_id == self.id }
+    if eligible?(order) and amount = calculator.compute(order.line_items)
       amount = order.item_total if amount > order.item_total
       order.coupon_credits.reload.clear unless combine? and order.coupon_credits.all? { |credit| credit.adjustment_source.combine? }
       order.save
-      credits.create({
+      coupon_credits.create({
           :order => order, 
           :amount => amount,
           :description => "#{I18n.t(:coupon)} (#{code})"
         })
     end