[FIX] mrp: allow skipping lot/sn on workorder

Usecase to reproduce:
- Create a MO for drawer with SEC assemble BoM
- Plan the workorders
- In the first workorder record the production without specify a lot or
serial number.
- Second workorder, register a new serial for finished product and
record production.

A UserError that prevent to use a new serial number is raised. It
happens because the system check the remaing quantity on other
workorders + the quantity already produced for the current lot. In this
case the remaining quantity for the first workorder is 0 and the current
lot was not produced. However it should count the lines without lot as
a 'remaining quantity' since they could be used later to create a new
serial or lot number.

This commit register the lines without lot and use them to raise the
UserError and compute the allowed lot domain for finished lots.

addons/mrp/models/mrp_workorder.py

@@ -130,8 +130,14 @@ def _onchange_final_lot_id(self):
             if line:
                 self.qty_producing = line.qty_done
 
+    @api.depends('production_id.workorder_ids.finished_workorder_line_ids',
+    'production_id.workorder_ids.finished_workorder_line_ids.qty_done',
+    'production_id.workorder_ids.finished_workorder_line_ids.lot_id')
     def _compute_allowed_lots_domain(self):
-        """ browse already created lot and respective quantities"""
+        """ Check if all the finished products has been assigned to a serial
+        number or a lot in other workorders. If yes, restrict the selectable lot
+        to the lot/sn used in other workorders.
+        """
         productions = self.mapped('production_id')
         for production in productions:
             if production.product_id.tracking == 'none':
@@ -141,7 +147,10 @@ def _compute_allowed_lots_domain(self):
             finished_workorder_lines = production.workorder_ids.mapped('finished_workorder_line_ids')
             qties_done_per_lot = defaultdict(list)
             for finished_workorder_line in finished_workorder_lines:
-                qties_done_per_lot[finished_workorder_line.lot_id.id].append(finished_workorder_line.qty_done)
+                # It is possible to have finished workorder lines without a lot (eg using the dummy
+                # test type). Ignore them when computing the allowed lots.
+                if finished_workorder_line.lot_id:
+                    qties_done_per_lot[finished_workorder_line.lot_id.id].append(finished_workorder_line.qty_done)
 
             qty_to_produce = production.product_qty
             allowed_lot_ids = self.env['stock.production.lot']
@@ -321,8 +330,8 @@ def record_production(self):
         # Transfer quantities from temporary to final move line or make them final
         self._update_raw_moves()
 
-        # Transfert lot and quantity produced to a finished workorder line
-        if self.product_tracking != 'none' and self.final_lot_id:
+        # Transfer lot (if present) and quantity produced to a finished workorder line
+        if self.product_tracking != 'none':
             self._create_or_update_finished_line()
 
         # Update workorder quantity produced
@@ -380,10 +389,13 @@ def _create_or_update_finished_line(self):
             # In this case we select 4 since it would conflict with the first
             # workorder otherwise.
             line = workorder.finished_workorder_line_ids.filtered(lambda line: line.lot_id == self.final_lot_id)
-            if line and float_compare(line.qty_done + workorder.qty_remaining, final_lot_quantity, precision_rounding=rounding) <= 0:
-                final_lot_quantity = line.qty_done + workorder.qty_remaining
-            elif float_compare(workorder.qty_remaining, final_lot_quantity, precision_rounding=rounding) < 0:
-                final_lot_quantity = workorder.qty_remaining
+            line_without_lot = workorder.finished_workorder_line_ids.filtered(lambda line: line.product_id == workorder.product_id and not line.lot_id)
+            quantity_remaining = workorder.qty_remaining + line_without_lot.qty_done
+            quantity = line.qty_done + quantity_remaining
+            if line and float_compare(quantity, final_lot_quantity, precision_rounding=rounding) <= 0:
+                final_lot_quantity = quantity
+            elif float_compare(quantity_remaining, final_lot_quantity, precision_rounding=rounding) < 0:
+                final_lot_quantity = quantity_remaining
 
         # final lot line for this lot on this workorder.
         current_lot_lines = self.finished_workorder_line_ids.filtered(lambda line: line.lot_id == self.final_lot_id)

addons/mrp/tests/test_workorder_operation.py

@@ -2,9 +2,10 @@
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
 from datetime import datetime, timedelta
-import unittest
-from odoo.tests import Form
+
 from odoo.addons.mrp.tests.common import TestMrpCommon
+from odoo.exceptions import UserError
+from odoo.tests import Form
 
 
 class TestWorkOrderProcess(TestMrpCommon):
@@ -720,6 +721,64 @@ def test_03_test_serial_number_defaults(self):
             workorder.record_production()
             self.assertEqual(workorder.state, 'done')
 
+    def test_03b_test_serial_number_defaults(self):
+        """ Check the constraint on the workorder final_lot. The first workorder
+        produces 2/2 units without serial number (serial is only required when
+        you register a component) then the second workorder try to register a
+        serial number. It should be allowed since the first workorder did not
+        specify a seiral number.
+        """
+        bom = self.env.ref('mrp.mrp_bom_laptop_cust_rout')
+        product = bom.product_tmpl_id.product_variant_id
+        product.tracking = 'serial'
+
+        lot_1 = self.env['stock.production.lot'].create({
+            'product_id': product.id,
+            'name': 'LOT000001'
+        })
+
+        lot_2 = self.env['stock.production.lot'].create({
+            'product_id': product.id,
+            'name': 'LOT000002'
+        })
+        self.env['stock.production.lot'].create({
+            'product_id': product.id,
+            'name': 'LOT000003'
+        })
+
+        mo_form = Form(self.env['mrp.production'])
+        mo_form.product_id = product
+        mo_form.bom_id = bom
+        mo_form.product_qty = 2.0
+        mo = mo_form.save()
+
+        mo.action_confirm()
+        mo.button_plan()
+
+        workorder_0 = mo.workorder_ids[0]
+        workorder_0.record_production()
+        workorder_0.record_production()
+        with self.assertRaises(UserError):
+            workorder_0.record_production()
+
+        workorder_1 = mo.workorder_ids[1]
+        with Form(workorder_1) as wo:
+            wo.final_lot_id = lot_1
+        workorder_1.record_production()
+
+        self.assertTrue(len(workorder_1.allowed_lots_domain) > 1)
+        with Form(workorder_1) as wo:
+            wo.final_lot_id = lot_2
+        workorder_1.record_production()
+
+        workorder_2 = mo.workorder_ids[2]
+        self.assertEqual(workorder_2.allowed_lots_domain, lot_1 | lot_2)
+
+        self.assertEqual(workorder_0.finished_workorder_line_ids.qty_done, 2)
+        self.assertFalse(workorder_0.finished_workorder_line_ids.lot_id)
+        self.assertEqual(sum(workorder_1.finished_workorder_line_ids.mapped('qty_done')), 2)
+        self.assertEqual(workorder_1.finished_workorder_line_ids.mapped('lot_id'), lot_1 | lot_2)
+
     def test_04_test_planning_date(self):
         """ Test that workorder are planned at the correct time. """
         # Remove attendances linked to the calendar, this means that the workcenter is working 24/7