[FIX] stock: fix blocking generate lots name

Issue, to reproduce:
- Create a product A tracked by serial
- Reciept one product A with a lot without digit
- validate this receipt, Ok
- Create a other receipt for product A,
- You cannot anymore open the detail wizard to enter a
SN/lot : get 'The lot name must contain at least one digit.'

Fix:
Remove the constraint and fallback by adding "0" at the end.

task-2652292

closes odoo/odoo#80104

X-original-commit: 5f75d5b1c8d5d4f37cbdc34daa79514226a17855
Signed-off-by: Arnold Moyaux <arm@odoo.com>
Signed-off-by: Rémy Voet <ryv@odoo.com>

addons/stock/models/stock_production_lot.py

@@ -40,8 +40,8 @@ class ProductionLot(models.Model):
         # We look if the first lot contains at least one digit.
         caught_initial_number = regex_findall(r"\d+", first_lot)
         if not caught_initial_number:
-            raise UserError(_('The lot name must contain at least one digit.'))
-        # We base the serie on the last number found in the base lot.
+            return self.generate_lot_names(first_lot + "0", count)
+        # We base the series on the last number found in the base lot.
         initial_number = caught_initial_number[-1]
         padding = len(initial_number)
         # We split the lot name to get the prefix and suffix.

addons/stock/tests/test_generate_serial_numbers.py

@@ -191,15 +191,17 @@ class StockGenerate(TransactionCase):
             default_move_id=move.id,
             default_next_serial_number='code-xxx',
         ))
-        wiz = form_wizard.save()
-        with self.assertRaises(UserError):
-            wiz.generate_serial_numbers()
 
         form_wizard.next_serial_count = 0
         # Must raise an exception because `next_serial_count` must be greater than 0.
         with self.assertRaises(ValidationError):
             form_wizard.save()
 
+        form_wizard.next_serial_count = 3
+        wiz = form_wizard.save()
+        wiz.generate_serial_numbers()
+        self.assertEqual(move.move_line_nosuggest_ids.mapped('lot_name'), ["code-xxx0", "code-xxx1", "code-xxx2"])
+
     def test_generate_04_generate_in_multiple_time(self):
         """ Generates a Serial Number for each move lines (except the last one)
         but with multiple assignments, and checks the generated Serial Numbers