[FIX] mrp,stock: compute correct quantity for stock move

Steps to reproduce:
- Install MRP
- Enable packages and multi-step routes
- Enable two steps manufacturing
- Create a component and a product
- Create a BOM for the product and add the component
- Make an MO for 100 units of the product
- Go to the picking and make a move of 20 units of the component with a
  destination package
- Put in pack
- Create the backorder and validate the transfer of the remaining
  components
- Go back to the MO

Issues:
Units reserved is wrong. The problem is when we are unpacking, we were
using result package inside the key. But what we want is to remove
quantity from the package the quantity originate from.

opw-3759006

closes odoo/odoo#160091

X-original-commit: 1cc04382f7ebaaa68ebe9313f1cd6b1284e13665
Signed-off-by: William Henrotin (whe) <whe@odoo.com>
Signed-off-by: Mattis Megevand (mmeg) <mmeg@odoo.com>

addons/mrp/tests/test_stock.py

@@ -227,6 +227,40 @@ class TestWarehouseMrp(common.TestMrpCommon):
         self.assertEqual(location_dest.id, self.depot_location.id)
         self.assertNotEqual(location_dest.id, self.stock_location.id)
 
+    def test_backorder_unpacking(self):
+        """ Test that movement of pack in backorder is correctly handled. """
+        warehouse = self.env['stock.warehouse'].search([('company_id', '=', self.env.company.id)], limit=1)
+        warehouse.write({'manufacture_steps': 'pbm'})
+
+        self.product_1.type = 'product'
+        self.env['stock.quant']._update_available_quantity(self.product_1, self.stock_location, 100)
+
+        mo_form = Form(self.env['mrp.production'])
+        mo_form.bom_id = self.bom_4
+        mo_form.product_qty = 100
+        mo = mo_form.save()
+        mo.action_confirm()
+
+        package = self.env['stock.quant.package'].create({})
+
+        picking = mo.picking_ids
+        picking.move_line_ids.write({
+            'quantity': 20,
+            'result_package_id': package.id,
+        })
+
+        res_dict = picking.button_validate()
+        wizard = Form(self.env[res_dict['res_model']].with_context(res_dict['context'])).save()
+        wizard.process()
+
+        backorder = picking.backorder_ids
+        backorder.move_line_ids.quantity = 80
+        backorder.button_validate()
+
+        self.assertEqual(picking.state, 'done')
+        self.assertEqual(backorder.state, 'done')
+        self.assertEqual(mo.move_raw_ids.move_line_ids.mapped('quantity_product_uom'), [20, 80])
+
 class TestKitPicking(common.TestMrpCommon):
     @classmethod
     def setUpClass(cls):

addons/stock/models/stock_move.py

@@ -1688,8 +1688,8 @@ Please change the quantity done or the rounding precision of your unit of measur
                     if not available_move_lines:
                         continue
                     for move_line in move.move_line_ids.filtered(lambda m: m.quantity_product_uom):
-                        if available_move_lines.get((move_line.location_id, move_line.lot_id, move_line.result_package_id, move_line.owner_id)):
-                            available_move_lines[(move_line.location_id, move_line.lot_id, move_line.result_package_id, move_line.owner_id)] -= move_line.quantity_product_uom
+                        if available_move_lines.get((move_line.location_id, move_line.lot_id, move_line.package_id, move_line.owner_id)):
+                            available_move_lines[(move_line.location_id, move_line.lot_id, move_line.package_id, move_line.owner_id)] -= move_line.quantity_product_uom
                     for (location_id, lot_id, package_id, owner_id), quantity in available_move_lines.items():
                         need = move.product_qty - sum(move.move_line_ids.mapped('quantity_product_uom'))
                         # `quantity` is what is brought by chained done move lines. We double check