[FIX] mrp: same unique SN

- Create a product with unique SN, create a BOM for this product
- Create a MO to produce 2 units
- Produce the first unit, create a lot number
- Produce the second unit, use the previously created lot number

Nothing prevents the user to do this. However, the user won't be able to
set the MO as "Done", but it is better to prevent the issue as soon as
possible.

opw-724944

addons/mrp/i18n/mrp.pot

@@ -3244,7 +3244,13 @@ msgid "You can not delete a Bill of Material with running manufacturing orders.\
 msgstr ""
 
 #. module: mrp
-#: code:addons/mrp/models/stock_move.py:123
+#: code:addons/mrp/models/stock_move.py:40
+#, python-format
+msgid "You can only produce 1.0 %s for products with unique serial number."
+msgstr ""
+
+#. module: mrp
+#: code:addons/mrp/models/stock_move.py:135
 #, python-format
 msgid "You cannot cancel a move move having already consumed material"
 msgstr ""

addons/mrp/models/stock_move.py

@@ -29,13 +29,15 @@ class StockMoveLots(models.Model):
     plus_visible = fields.Boolean("Plus Visible", compute='_compute_plus')
 
     @api.one
-    @api.constrains('lot_id')
+    @api.constrains('lot_id', 'quantity_done')
     def _check_lot_id(self):
         if self.move_id.product_id.tracking == 'serial':
             lots = set([])
             for move_lot in self.move_id.move_lot_ids.filtered(lambda r: not r.lot_produced_id):
                 if move_lot.lot_id in lots:
                     raise exceptions.UserError(_('You cannot use the same serial number in two different lines.'))
+                if float_compare(move_lot.quantity_done, 1.0, precision_rounding=move_lot.product_id.uom_id.rounding) == 1:
+                    raise exceptions.UserError(_('You can only produce 1.0 %s for products with unique serial number.') % move_lot.product_id.uom_id.name)
                 lots.add(move_lot.lot_id)
 
     def _compute_plus(self):