[FIX] stock: select dest location of a SML

On a SML, when setting the done quantity, the onchange may change the
destination location selected by the user

To reproduce the issue:
1. In Settings:
    - Enable "Storage Locations"
    - (Then, ensure "Storage Categories" is disabled)
2. Inventory > Operations Types, edit "Internal Transfers":
    - Enable "Show Detailed Operations"
3. Create an internal transfer IT:
    - From: WH/Stock
    - To: WH/Stock
4. Add a detailed operations to IT:
    - Product: anyone
    - To: WH/Stock/Shelf 1
    - Done: 1

Error: One the field "Done" is modified, the "To" changes and becomes
"WH/Stock". This location should not change (it should be
"WH/Stock/Shelf 1")

When setting the done quantity, an onchange recomputes the destination
location of the SML. To do so, it uses a initial location and searches
among its children. Here is the issue: when "Storage Categories" is
disabled, this initial location should be the one selected by the user.

OPW-2704665

closes odoo/odoo#85151

X-original-commit: 4202e46a8313fa9f1487d372ef0cb771f769be8d
Signed-off-by: Arnold Moyaux <arm@odoo.com>
Signed-off-by: Adrien Widart <awt@odoo.com>

addons/stock/models/stock_move_line.py

@@ -208,6 +208,8 @@ class StockMoveLine(models.Model):
                 packaging=self.move_id.product_packaging_id, additional_qty=additional_qty)
 
     def _get_default_dest_location(self):
+        if not self.user_has_groups('stock.group_stock_storage_categories'):
+            return self.location_dest_id[:1]
         if self.env.context.get('default_location_dest_id'):
             return self.env['stock.location'].browse([self.env.context.get('default_location_dest_id')])
         return (self.move_id.location_dest_id or self.picking_id.location_dest_id or self.location_dest_id)[0]

addons/stock/tests/test_move.py

@@ -5476,3 +5476,40 @@ class StockMove(TransactionCase):
         self.assertEqual(move.reserved_availability, 2)
         # check forecast_availability expressed in product base uom
         self.assertEqual(move.forecast_availability, 24)
+
+    def test_SML_location_selection(self):
+        """
+        Suppose the setting 'Storage Categories' disabled and the option 'Show Detailed Operations'
+        for operation 'Internal Transfer' enabled.
+        A user creates an internal transfer from F to T, confirms it then adds a SML and selects
+        another destination location L (with L a child of T). When the user completes the field
+        `qty_done`, the onchange should n't change the destination location L
+        """
+
+        self.env.user.write({'groups_id': [(3, self.env.ref('stock.group_stock_storage_categories').id)]})
+        internal_transfer = self.env.ref('stock.picking_type_internal')
+        internal_transfer.show_operations = True
+
+        picking = self.env['stock.picking'].create({
+            'picking_type_id': internal_transfer.id,
+            'location_id': self.stock_location.id,
+            'location_dest_id': self.customer_location.id,
+        })
+        self.env['stock.move'].create({
+            'name': self.product_consu.name,
+            'product_id': self.product_consu.id,
+            'product_uom': self.uom_unit.id,
+            'product_uom_qty': 2.0,
+            'picking_id': picking.id,
+            'location_id': picking.location_id.id,
+            'location_dest_id': picking.location_dest_id.id,
+        })
+
+        picking.action_confirm()
+
+        with Form(picking) as form:
+            with form.move_line_ids_without_package.edit(0) as line:
+                line.location_dest_id = self.stock_location.child_ids[0]
+                line.qty_done = 1
+
+        self.assertEqual(picking.move_line_ids_without_package.location_dest_id, self.stock_location.child_ids[0])