Display out of stock banner when viewing cart directly

app/controllers/checkout_controller.rb

@@ -153,12 +153,10 @@ class CheckoutController < Spree::CheckoutController
   def raise_insufficient_quantity
     respond_to do |format|
       format.html do
-        flash[:error] = t(:spree_inventory_error_flash_for_insufficient_quantity)
         redirect_to cart_path
       end
 
       format.json do
-        flash[:error] = t(:spree_inventory_error_flash_for_insufficient_quantity)
         render json: {path: cart_path}, status: 400
       end
     end

app/controllers/enterprises_controller.rb

@@ -32,7 +32,6 @@ class EnterprisesController < BaseController
 
   def check_stock_levels
     if current_order(true).insufficient_stock_lines.present?
-      flash[:error] = t(:spree_inventory_error_flash_for_insufficient_quantity)
       redirect_to spree.cart_path
     end
   end

app/controllers/spree/orders_controller_decorator.rb

@@ -1,9 +1,9 @@
 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
+  after_filter  :populate_variant_attributes, only: :populate
+  before_filter :update_distribution, only: :update
+  before_filter :filter_order_params, only: :update
 
   prepend_before_filter :require_order_cycle, only: :edit
   prepend_before_filter :require_distributor_chosen, only: :edit
@@ -12,13 +12,19 @@ Spree::OrdersController.class_eval do
   include OrderCyclesHelper
   layout 'darkswarm'
 
+
   # Patching to redirect to shop if order is empty
   def edit
     @order = current_order(true)
+
     if @order.line_items.empty?
       redirect_to main_app.shop_path
     else
       associate_user
+
+      if @order.insufficient_stock_lines.present?
+        flash[:error] = t(:spree_inventory_error_flash_for_insufficient_quantity)
+      end
     end
   end
 

spec/controllers/spree/orders_controller_spec.rb

@@ -42,6 +42,26 @@ describe Spree::OrdersController do
     flash[:info].should == "The hub you have selected is temporarily closed for orders. Please try again later."
   end
 
+  describe "when an item has insufficient stock" do
+    let(:order) { subject.current_order(true) }
+    let(:oc) { create(:simple_order_cycle, distributors: [d], variants: [variant]) }
+    let(:d) { create(:distributor_enterprise, shipping_methods: [create(:shipping_method)], payment_methods: [create(:payment_method)]) }
+    let(:variant) { create(:variant, on_demand: false, on_hand: 5) }
+    let(:line_item) { order.line_items.last }
+
+    before do
+      order.set_distribution! d, oc
+      order.add_variant variant, 5
+      variant.update_attributes! on_hand: 3
+    end
+
+    it "displays a flash message when we view the cart" do
+      spree_get :edit
+      expect(response.status).to eq 200
+      flash[:error].should == "An item in your cart has become unavailable."
+    end
+  end
+
   describe "returning stock levels in JSON on success" do
     let(:product) { create(:simple_product) }
 
@@ -120,7 +140,7 @@ describe Spree::OrdersController 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, on_hand: 110).master)
+        li = order.add_variant(create(:simple_product, on_hand: 110).variants.first)
         spree_get :update, order: { line_items_attributes: {
           "0" => {quantity: "0", id: "9999"},
           "1" => {quantity: "99", id: li.id}