Move LineItem update to source of change (order update). On empty cart, re-instanciate shipping method adjustment, fixing no shipping fees after empty cart bug.

app/models/spree/line_item_decorator.rb

@@ -7,17 +7,14 @@ Spree::LineItem.class_eval do
 
 
   def itemwise_shipping_cost
-    # When order has not yet been placed, update shipping method in case order
-    # has changed to a distributor with a different shipping method
-    if %w(cart address delivery resumed).include? self.order.state
-      set_itemwise_shipping_method
-      save! if shipping_method_id_changed?
-    end
-
     order = OpenStruct.new :line_items => [self]
     shipping_method.compute_amount(order)
   end
 
+  def update_itemwise_shipping_method_without_callbacks!(distributor)
+    update_column(:shipping_method_id, self.product.shipping_method_for_distributor(distributor).id)
+  end
+
 
   private
 

app/models/spree/order_decorator.rb

@@ -7,9 +7,16 @@ Spree::Order.class_eval do
   attr_accessible :distributor_id
 
   before_validation :shipping_address_from_distributor
+  before_save :update_line_item_shipping_methods
   after_create :set_default_shipping_method
 
   
+  def empty!
+    line_items.destroy_all
+    adjustments.destroy_all
+    set_default_shipping_method
+  end
+
   def products_available_from_new_distributor
     # Check that the line_items in the current order are available from a newly selected distributor
     errors.add(:distributor_id, "cannot supply the products in your cart") unless DistributorChangeValidator.new(self).can_change_to_distributor?(distributor)
@@ -66,4 +73,11 @@ Spree::Order.class_eval do
       end
     end
   end
+
+  def update_line_item_shipping_methods
+    if %w(cart address delivery resumed).include? state
+      self.line_items.each { |li| li.update_itemwise_shipping_method_without_callbacks!(distributor) }
+      self.update!
+    end
+  end
 end

spec/features/consumer/checkout_spec.rb

@@ -2,7 +2,7 @@ require "spec_helper"
 
 feature %q{
     As a consumer
-    I want select a distributor for collection
+    I want to select a distributor for collection
     So that I can pick up orders from the closest possible location
 } do
   include AuthenticationWorkflow
@@ -116,6 +116,27 @@ feature %q{
     page.should have_selector 'span.shipping-total', text: '$4.68'
   end
 
+  scenario "adding a product to cart after emptying cart shows correct delivery fees" do
+    # When I add a product to my cart
+    login_to_consumer_section
+    click_link @product_1.name
+    select @distributor.name, :from => 'distributor_id'
+    click_button 'Add To Cart'
+
+    # Then I should see the correct delivery fee
+    page.should have_selector 'span.grand-total', text: '$20.99'
+
+    # When I empty my cart and add the product again
+    click_button 'Empty Cart'
+    click_link 'Continue shopping'
+    click_link @product_1.name
+    select @distributor.name, :from => 'distributor_id'
+    click_button 'Add To Cart'
+
+    # Then I should see the correct delivery fee
+    page.should have_selector 'span.grand-total', text: '$20.99'
+  end
+
   scenario "buying a product", :js => true do
     login_to_consumer_section