stock_move_line_change_lot: fix unreserve lines from same picking

Makes no sense to unreserve lines that are in the same picking.
In this case the lines should simply swap the lots.

Author: simahawk

stock_move_line_change_lot/models/stock_move_line.py

@@ -39,13 +39,13 @@ def _change_lot_free_other_lines(self, need, location, product, lot, package):
             ],
             order="quantity desc",
         )
-        # Favor lines from non-printed pickings.
-        other_lines.sorted(
-            lambda ml: (
-                ml.picking_id == self.picking_id or not ml.picking_id.printed,
-                -ml.quantity,
-            )
+        # collect and skip lines from the same picking
+        other_lines_same_picking = other_lines.filtered(
+            lambda x: x.picking_id == self.picking_id
         )
+        other_lines -= other_lines_same_picking
+        # Favor lines from non-printed pickings.
+        other_lines.sorted(lambda ml: (not ml.picking_id.printed, -ml.quantity))
         # Stop when required quantity is reached
         for line in other_lines:
             freed_quantity += line.quantity_product_uom
@@ -58,7 +58,15 @@ def _change_lot_free_other_lines(self, need, location, product, lot, package):
             if not is_lesser(freed_quantity, need, rounding):
                 # We reached the required quantity
                 break
-
+        # Lines from the same picking should:
+        # * count qty as available
+        # * be swapped to original lot
+        # * re-assigned
+        freed_quantity += sum(other_lines_same_picking.mapped("quantity_product_uom"))
+        to_reassign_moves |= other_lines_same_picking.move_id
+        other_lines_same_picking.with_context(
+            bypass_reservation_update=True
+        ).lot_id = self.lot_id
         return (freed_quantity, to_reassign_moves)
 
     def write(self, vals):
@@ -159,15 +167,13 @@ def _do_change_lot(self, vals):
                     available_quantity, move_line.quantity_product_uom, rounding
                 ):
                     need = move_line.quantity_product_uom - available_quantity
-                    (
-                        freed_quantity,
-                        to_reassign_moves,
-                    ) = move_line._change_lot_free_other_lines(
-                        need, location, product, lot, package
+                    (freed_quantity, to_reassign_moves) = (
+                        move_line._change_lot_free_other_lines(
+                            need, location, product, lot, package
+                        )
                     )
                     available_quantity += freed_quantity
                     to_reassign_moves |= to_reassign_moves
-
                     if is_lesser(
                         available_quantity, move_line.quantity_product_uom, rounding
                     ) and is_bigger(available_quantity, 0, rounding):

stock_move_line_change_lot/tests/test_change_lot.py

@@ -256,6 +256,40 @@ def test_change_lot_reserved_qty(self):
             line2, lambda: line2.quantity_product_uom, lot=initial_lot
         )
 
+    def test_change_lot_reserved_qty_same_picking(self):
+        """Scan a lot already reserved by other lines in the same picking.
+
+        It should NOT unreserve the other line, use the lot for the current line,
+        and swap the lot to the other move.
+        """
+        initial_lot1 = self._create_lot(self.product_a)
+        initial_lot2 = self._create_lot(self.product_a)
+        self._update_qty_in_location(self.shelf1, self.product_a, 10, lot=initial_lot1)
+        self._update_qty_in_location(self.shelf1, self.product_a, 10, lot=initial_lot2)
+        picking = self._create_picking(lines=[(self.product_a, 20)])
+        picking.action_assign()
+        line1 = picking.move_line_ids[0]
+        line2 = picking.move_line_ids[1]
+        self.assertEqual(line1.lot_id, initial_lot1)
+        self.assertEqual(line2.lot_id, initial_lot2)
+
+        # swap lot 2 on line 1
+        self._change_lot(line1, initial_lot2)
+        self.assertRecordValues(
+            line1, [{"lot_id": initial_lot2.id, "quantity_product_uom": 10}]
+        )
+        # line 2 has been assigned to lot 1
+        self.assertRecordValues(
+            line2, [{"lot_id": initial_lot1.id, "quantity_product_uom": 10}]
+        )
+        # check that reservations have been updated
+        self.assert_quant_reserved_qty(
+            line1, lambda: line1.quantity_product_uom, lot=initial_lot2
+        )
+        self.assert_quant_reserved_qty(
+            line2, lambda: line2.quantity_product_uom, lot=initial_lot1
+        )
+
     def test_change_lot_reserved_partial_qty(self):
         """Scan a lot already reserved by other lines and can only be reserved
         partially
@@ -340,7 +374,7 @@ def test_change_lot_reserved_qty_done(self):
         )
 
     def test_change_lot_different_location(self):
-        "If the scanned lot is in a different location, we cannot process it"
+        """If the scanned lot is in a different location, we cannot process it"""
         initial_lot = self._create_lot(self.product_a)
         self._update_qty_in_location(self.shelf1, self.product_a, 10, lot=initial_lot)
         picking = self._create_picking(lines=[(self.product_a, 10)])