[FIX] sale_timesheet: default_service_policy not working in product form

Before this commit:
- There is a bug in odoo enterprise.
project.project form view > invoicing notebook > services created using create and edit
should be configured by default with an 'invoicing policy' set to 'based on timesheets'.
Technically, while we're using 'default_service_policy' with the right value, we're
getting a different value in the form.

After this commit:
- The bug is fixed.

closes odoo/odoo#134360

X-original-commit: fa034b2a
Signed-off-by: Xavier Bol (xbo) <xbo@odoo.com>

addons/sale_timesheet/models/product.py

@@ -157,9 +157,14 @@ class ProductProduct(models.Model):
         self.ensure_one()
         return self.type == 'service' and self.service_policy == 'delivered_timesheet'
 
+    def _inverse_service_policy(self):
+        for product in self:
+            if product.service_policy:
+                product.invoice_policy, product.service_type = SERVICE_TO_GENERAL.get(product.service_policy, (False, False))
+
     @api.onchange('service_policy')
     def _onchange_service_policy(self):
-        self.product_tmpl_id._inverse_service_policy()
+        self._inverse_service_policy()
         vals = self.product_tmpl_id._get_onchange_service_policy_updates(self.service_tracking,
                                                                         self.service_policy,
                                                                         self.project_id,

addons/sale_timesheet/tests/test_project.py

@@ -3,7 +3,7 @@
 
 from odoo import Command
 from .common import TestCommonSaleTimesheet
-from odoo.tests import tagged
+from odoo.tests import tagged, Form
 
 
 @tagged('post_install', '-at_install')
@@ -123,3 +123,7 @@ class TestProject(TestCommonSaleTimesheet):
         employee_mapping.cost = self.employee_user.timesheet_cost
         employee_mapping.employee_id = self.employee_company_B
         self.assertEqual(employee_mapping.cost, self.employee_company_B.timesheet_cost)
+
+    def test_open_product_form_with_default_service_policy(self):
+        form = Form(self.env['product.product'].with_context(default_detailed_type='service', default_service_policy='delivered_timesheet'))
+        self.assertEqual('delivered_timesheet', form.service_policy)