[FIX] website_sale_loyalty: add product when exists as reward in cart

Issue:
======
When we have a product as a free product reward in cart and we want to
add the same product from the shop nothing will happen and the cart
stays the same.

Steps to reproduce the issue:
=============================
- Create a loyalty program with the following options:
type: pormotions
rule: minimum quantity :1 , gran 1, minimum purchase 0, per order,
product:  select anyone
reward: type : free product , quantity rewarded : 1, product : select
any other product
- Go to website and add the product from the rule to cart
- Go to cart and claim reward
- Go back to shop and add the product from the reward to cart
- Go to cart
- The cart stays the same

Issue:
======
When searching for the `line` it doesn't consider if the line is a
reward or not.

Solution:
=========
We filter the reward lines if `line_id=False`

opw-3550585

closes odoo/odoo#143581

X-original-commit: 2b97bb83b312f553d3ec1b6e96a74c744955aed6
Signed-off-by: Morgane Demesmaeker <edm@odoo.com>

addons/website_sale_loyalty/models/sale_order.py

@@ -220,3 +220,12 @@ class SaleOrder(models.Model):
                     else:
                         res[coupon] = reward
         return res
+
+    def _cart_find_product_line(self, product_id, line_id=None, **kwargs):
+        """ Override to filter out reward lines from the cart lines.
+
+        These are handled by the _update_programs_and_rewards and _auto_apply_rewards methods.
+        """
+        lines = super()._cart_find_product_line(product_id, line_id, **kwargs)
+        lines = lines.filtered(lambda l: not l.is_reward_line) if not line_id else lines
+        return lines

addons/website_sale_loyalty/tests/__init__.py

@@ -4,3 +4,4 @@ from . import test_apply_pending_coupon
 from . import test_sale_coupon_multiwebsite
 from . import test_shop_sale_coupon
 from . import test_website_sale_loyalty_delivery
+from . import test_free_product_reward

addons/website_sale_loyalty/tests/test_free_product_reward.py

@@ -0,0 +1,81 @@
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo import http
+from odoo.tests.common import HttpCase
+from odoo.tests import tagged
+from odoo.addons.website.tools import MockRequest
+from odoo.addons.website_sale_loyalty.controllers.main import WebsiteSale
+
+@tagged('post_install', '-at_install')
+class TestFreeProductReward(HttpCase):
+
+    def setUp(self):
+        super().setUp()
+
+        self.WebsiteSaleController = WebsiteSale()
+        self.website = self.env['website'].browse(1)
+
+        self.sofa = self.env['product.product'].create({
+            'name': 'Test Sofa',
+            'list_price': 2950.0,
+            'website_published': True,
+        })
+
+        self.carpet = self.env['product.product'].create({
+            'name': 'Test Carpet',
+            'list_price': 500.0,
+            'website_published': True,
+        })
+
+        # Disable any other program
+        self.program = self.env['loyalty.program'].search([]).write({'active': False})
+
+        self.program = self.env['loyalty.program'].create({
+            'name': 'Get a product for free',
+            'program_type': 'promotion',
+            'applies_on': 'current',
+            'trigger': 'auto',
+            'rule_ids': [(0, 0, {
+                'minimum_qty': 1,
+                'minimum_amount': 0.00,
+                'reward_point_amount': 1,
+                'reward_point_mode': 'order',
+                'product_ids': self.sofa,
+            })],
+            'reward_ids': [(0, 0, {
+                'reward_type': 'product',
+                'reward_product_id': self.carpet.id,
+                'reward_product_qty': 1,
+                'required_points': 1,
+            })],
+        })
+
+        self.steve = self.env['res.partner'].create({
+            'name': 'Steve Bucknor',
+            'email': 'steve.bucknor@example.com',
+        })
+
+        self.empty_order = self.env['sale.order'].create({
+            'partner_id': self.steve.id
+        })
+
+        installed_modules = set(self.env['ir.module.module'].search([
+            ('state', '=', 'installed'),
+        ]).mapped('name'))
+        for _ in http._generate_routing_rules(installed_modules, nodb_only=False):
+            pass
+
+    def test_add_product_to_cart_when_it_exist_as_free_product(self):
+        # This test the flow when we claim a reward in the cart page and then we
+        # want to add the product again
+        order = self.empty_order
+        with MockRequest(self.env, website=self.website, sale_order_id=order.id, website_sale_current_pl=1):
+            self.WebsiteSaleController.cart_update_json(self.sofa.id, set_qty=1)
+            self.WebsiteSaleController.claim_reward(self.program.reward_ids[0].id)
+            self.WebsiteSaleController.cart_update_json(self.carpet.id, set_qty=1)
+            sofa_line = order.order_line.filtered(lambda line: line.product_id.id == self.sofa.id)
+            carpet_reward_line = order.order_line.filtered(lambda line: line.product_id.id == self.carpet.id and line.is_reward_line)
+            carpet_line = order.order_line.filtered(lambda line: line.product_id.id == self.carpet.id and not line.is_reward_line)
+            self.assertEqual(sofa_line.product_uom_qty, 1, "Should have only 1 qty of Sofa")
+            self.assertEqual(carpet_reward_line.product_uom_qty, 1, "Should have only 1 qty for the carpet as reward")
+            self.assertEqual(carpet_line.product_uom_qty, 1, "Should have only 1 qty for carpet as non reward")