[FW][FIX] website_sale_loyalty: allow to remove coupon from cart

[fw-bot]

Steps to reproduce

• Install eCommerce app
• Go to Settings and enable Discounts, Loyalty & Gift Card option
• Go to Website app > eCommerce > Loyalty > Discount & Loyalty
• Create a new coupon by setting the Program Type to Coupons and then save
• Generate a new coupon by clicking the GENERATE COUPONS button.
• Go to Website > site > Homepage
• Go to Shop page
• Add a product to the cart
• Apply the coupon code created
• Remove the coupon code by clicking the bin icon next to the coupon code line
• The coupon code is NOT removed.

Investigation

First, we'll take a look on what happens when a coupon code is applied

• When a coupon code is applied, a new sale.order.line is created for it.
• That triggers super()._compute_website_order_line()

  odoo/addons/website_sale_loyalty/models/sale_order.py

  Line 111 in d8ec773

  super()._compute_website_order_line()

  which filters out the discount order line

  odoo/addons/website_sale/models/sale_order.py

  Line 66 in d8ec773

  order.website_order_line = order.order_line.filtered(lambda l: l._show_in_cart())

  via the _show_in_cart() method

  odoo/addons/website_sale_loyalty/models/sale_order_line.py

  Line 12 in d8ec773

  return self.reward_id.reward_type != 'discount' and super()._show_in_cart()

• Then a new temporary sale.order.line is created by

  odoo/addons/website_sale_loyalty/models/sale_order.py

  Line 121 in d8ec773

  new_lines += self.env['sale.order.line'].new({

  meaning that is has no id
• ⚠️ Note that we can only apply one coupon from the same program type.

Second, Let's take a look on what happens when we try to remove a coupon code

• A call is made to cart_update_json() which calls

  odoo/addons/website_sale/controllers/main.py

  Lines 811 to 819 in d8ec773

  	values = order._cart_update(
  	product_id=product_id,
  	line_id=line_id,
  	add_qty=add_qty,
  	set_qty=set_qty,
  	product_custom_attribute_values=product_custom_attribute_values,
  	no_variant_attribute_values=no_variant_attribute_values,
  	**kw
  	)

  which calls

  odoo/addons/website_sale_loyalty/models/sale_order.py

  Line 159 in d8ec773

  def _cart_update(self, *args, **kwargs):

• But as noted above the coupon order line has no id being a temporary record. Hence the line_id is None which basically cancels the cart update.

opw-3744910

Forward-Port-Of: #154680

[robodoo]

Pull request status dashboard.

[fw-bot]

This PR targets saas-16.2 and is part of the forward-port chain. Further PRs will be created up to master.

More info at https://github.com/odoo/odoo/wiki/Mergebot#forward-port

[fw-bot]

@AH-Yussef @Demesmaeker the next pull request (#156383) is in conflict. You can merge the chain up to here by saying

@fw-bot r+

More info at https://github.com/odoo/odoo/wiki/Mergebot#forward-port

[AH-Yussef]

@fw-bot r+