Patching a bug in which we'd 404 if deleting items from a cart twice in parallel

app/controllers/spree/orders_controller_decorator.rb

@@ -3,6 +3,7 @@ require 'spree/core/controller_helpers/order_decorator'
 Spree::OrdersController.class_eval do
   after_filter  :populate_variant_attributes, :only => :populate
   before_filter :update_distribution, :only => :update
+  before_filter :filter_order_params, :only => :update
 
   # Patch Orders#populate to provide distributor_id and order_cycle_id to OrderPopulator
   def populate
@@ -62,6 +63,18 @@ Spree::OrdersController.class_eval do
     end
   end
 
+  def filter_order_params
+    if params[:order] and params[:order][:line_items_attributes]
+      params[:order][:line_items_attributes] = remove_missing_line_items(params[:order][:line_items_attributes])
+    end
+  end
+
+  def remove_missing_line_items(attrs)
+    attrs.select do |i, line_item|
+      Spree::LineItem.find_by_id(line_item[:id])
+    end
+  end
+
   def clear
     @order = current_order(true)
     @order.empty!
@@ -107,4 +120,5 @@ Spree::OrdersController.class_eval do
       spree_current_user.cart.add_variant hash[:variants].keys.first, hash[:variants].values.first, distributor, order_cycle, current_currency
     end
   end
+
 end

spec/controllers/orders_controller_spec.rb

@@ -112,11 +112,38 @@ describe Spree::OrdersController do
     end
   end
 
+  context "removing line items from cart" do
+    describe "when I pass params that includes a line item no longer in our cart" do
+      it "should silently ignore the missing line item" do
+        order = subject.current_order(true)
+        li = order.add_variant(create(:simple_product).master)
+        spree_get :update, order: { line_items_attributes: {
+          "0" => {quantity: "0", id: "9999"},
+          "1" => {quantity: "99", id: li.id}
+        }}
+        response.status.should == 302
+        li.reload.quantity.should == 99
+      end
+    end
+
+    it "filters line items that are missing from params" do
+      order = subject.current_order(true)
+      li = order.add_variant(create(:simple_product).master)
+
+      attrs = {
+        "0" => {quantity: "0", id: "9999"},
+        "1" => {quantity: "99", id: li.id}
+      }
+
+      controller.remove_missing_line_items(attrs).should == {
+        "1" => {quantity: "99", id: li.id}
+      }
+    end
+  end
 
   private
 
   def num_items_in_cart
     Spree::Order.last.andand.line_items.andand.count || 0
   end
-
 end