[FIX] stock,purchase_stock: multi-company issue on routes with a single company

Step to follow

Do not activate multiple companies, keep it standard to 1
Enable multi-locations and routes
Create a second location for raw materials and a new Receipt operation type with the new location as destination location
Go to routes -> edit the buy route -> add a second rule with "Buy" and save.

Cause of the issue

When a stock rule is created from a stock route, the default company
cannot be found as there is none assigned to the stock route.

Solution

Override the default_get method for stock rules in order to use the
current company

opw-2578984

closes odoo/odoo#74380

X-original-commit: 2b8d7d76adceeca16f97e394a6734bb5be633c3b
Signed-off-by: Victor Feyens (vfe) <vfe@odoo.com>

addons/purchase_stock/tests/__init__.py

@@ -17,3 +17,4 @@ from . import test_replenish_wizard
 from . import test_reordering_rule
 from . import test_move_cancel_propagation
 from . import test_product_template
+from . import test_routes

addons/purchase_stock/tests/test_routes.py

@@ -0,0 +1,53 @@
+from odoo.tests.common import TransactionCase, Form
+
+
+class TestRoutes(TransactionCase):
+
+    def test_allow_rule_creation_for_route_without_company(self):
+        self.env['res.config.settings'].write({
+            'group_stock_adv_location': True,
+            'group_stock_multi_locations': True,
+        })
+
+        warehouse = self.env['stock.warehouse'].search([('company_id', '=', self.env.company.id)], limit=1)
+
+        location_1 = self.env['stock.location'].create({
+            'name': 'loc1',
+            'location_id': warehouse.id
+        })
+
+        location_2 = self.env['stock.location'].create({
+            'name': 'loc2',
+            'location_id': warehouse.id
+        })
+
+        receipt_1 = self.env['stock.picking.type'].create({
+            'name': 'Receipts from loc1',
+            'sequence_code': 'IN1',
+            'code': 'incoming',
+            'warehouse_id': warehouse.id,
+            'default_location_dest_id': location_1.id,
+        })
+
+        receipt_2 = self.env['stock.picking.type'].create({
+            'name': 'Receipts from loc2',
+            'sequence_code': 'IN2',
+            'code': 'incoming',
+            'warehouse_id': warehouse.id,
+            'default_location_dest_id': location_2.id,
+        })
+
+        route = self.env['stock.location.route'].create({
+            'name': 'Buy',
+            'company_id': False
+        })
+
+        with Form(route) as r:
+            with r.rule_ids.new() as line:
+                line.name = 'first rule'
+                line.action = 'buy'
+                line.picking_type_id = receipt_1
+            with r.rule_ids.new() as line:
+                line.name = 'second rule'
+                line.action = 'buy'
+                line.picking_type_id = receipt_2

addons/stock/models/stock_rule.py

@@ -34,6 +34,13 @@ class StockRule(models.Model):
     _order = "sequence, id"
     _check_company_auto = True
 
+    @api.model
+    def default_get(self, fields_list):
+        res = super().default_get(fields_list)
+        if 'company_id' in fields_list and not res['company_id']:
+            res['company_id'] = self.env.company.id
+        return res
+
     name = fields.Char(
         'Name', required=True, translate=True,
         help="This field will fill the packing origin and the name of its moves")