The error occurred because:
1. OrderForm.save(commit=False) was calling reset_delivery_cost()
2. reset_delivery_cost() uses DeliveryCostCalculator which accesses order.items
3. But items don't exist yet when order is not saved to DB
Solution:
- OrderForm.save() now only calls reset_delivery_cost() when commit=True
- order_create() explicitly calls reset_delivery_cost() AFTER saving items
- This ensures items exist in DB before delivery cost calculation
Error was: 'Order' instance needs to have a primary key value before this relationship can be used.
Andrey Smakotin
39ab474a3c