[FIX] loyalty: Prevent reward_ids to be reset to default

Steps:
    - Install `sale_management`
    - Go to `Discount & Loyalty`
    - Create a new one and set a name
    - Change default program type from `discount` to `buy x get y`
    - Remove the default rewards
    - Add a new one (the default one)
    - Click `Save & Close`
    - Trigger save

Rewards is reset to default `discount` instead of `buy x get y`

closes odoo/odoo#138523

X-original-commit: 798c69f44bfde2f66826775a5a11fe5e51adb9a8
Signed-off-by: Victor Feyens (vfe) <vfe@odoo.com>

addons/loyalty/tests/test_loyalty.py

@@ -5,7 +5,7 @@ from psycopg2 import IntegrityError
 
 from odoo.exceptions import ValidationError
 from odoo.fields import Command
-from odoo.tests import tagged, TransactionCase
+from odoo.tests import tagged, TransactionCase, Form
 from odoo.tools import mute_logger
 
 from unittest.mock import patch
@@ -113,6 +113,17 @@ class TestLoyalty(TransactionCase):
         })
         self.assertTrue(all(r.reward_type == 'product' for r in self.program.reward_ids))
 
+    def test_loyalty_program_preserve_reward_with_always_edit(self):
+        with Form(self.env['loyalty.program']) as program_form:
+            program_form.name = 'Test'
+            program_form.program_type = 'buy_x_get_y'
+            program_form.reward_ids.remove(0)
+            with program_form.reward_ids.new() as new_reward:
+                new_reward.reward_product_qty = 2
+            program = program_form.save()
+            self.assertEqual(program.reward_ids.reward_type, 'product')
+            self.assertEqual(program.reward_ids.reward_product_qty, 2)
+
     def test_archiving_unarchiving(self):
         self.program.write({
             'reward_ids': [

addons/loyalty/views/loyalty_reward_views.xml

@@ -14,7 +14,7 @@
                 <sheet>
                     <group>
                         <group string="Reward" name="reward_type_group">
-                            <field name="reward_type" widget="selection" readonly="program_type == 'buy_x_get_y'"/>
+                            <field name="reward_type" widget="selection" force_save="1" readonly="program_type == 'buy_x_get_y'"/>
                             <label for="discount" invisible="reward_type != 'discount'"/>
                             <div class="d-flex flex-row" invisible="reward_type != 'discount'">
                                 <field name="discount" class="oe_inline me-1"/>