[FIX] purchase: fix qty received computation

Expected behavior : The log note sent when received quantity is updated should take into account the quantity already received.

Current behavior : The log note sent doesn't take into account the quantity already received for a 'stock_moves'. So it always displays `Received Quantity: 0.0 -> quantity in stock` instead of `Received Quantity: quantity already received -> quantity in stock`

Steps to reproduce the error :
- Create a RFQ with few units of a Storable Product (e.g. 5 units)
- Partially validate the receipt and create a backorder (e.g. 3 units)
- Validate the backorder (e.g. 2 units)

Log notes should be :
`Received Quantity: 0.0 -> 3.0`
`Received Quantity: 3.0 -> 5.0`

But are :
`Received Quantity: 0.0 -> 3.0`
`Received Quantity: 0.0 -> 5.0`

The value is always equal to 0.0 because `qty_received_method == 'stock_moves'` so `line.qty_received` is overridden by 0.0 in parent `_compute_qty_received` even though its value is already set to 0.0 (default) or to the quantity already received

opw-2600221
opw-2613116

closes odoo/odoo#78858

X-original-commit: 0c8ea86fb8d706af139cd2d412d01487e5899df6
Signed-off-by: William Henrotin (whe) <whe@odoo.com>

addons/purchase_stock/models/purchase.py

@@ -292,7 +292,8 @@ class PurchaseOrderLine(models.Model):
 
     @api.depends('move_ids.state', 'move_ids.product_uom_qty', 'move_ids.product_uom')
     def _compute_qty_received(self):
-        super(PurchaseOrderLine, self)._compute_qty_received()
+        from_stock_lines = self.filtered(lambda order_line: order_line.qty_received_method == 'stock_moves')
+        super(PurchaseOrderLine, self - from_stock_lines)._compute_qty_received()
         for line in self:
             if line.qty_received_method == 'stock_moves':
                 total = 0.0

addons/purchase_stock/tests/test_purchase_order.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
-
+import re
 from datetime import datetime, timedelta
 
 from odoo.tools import DEFAULT_SERVER_DATETIME_FORMAT
@@ -366,3 +366,45 @@ class TestPurchaseOrder(ValuationReconciliationTestCommon):
         picking.move_line_ids.write({'qty_done': 3.66})
         picking.button_validate()
         self.assertEqual(po.order_line.mapped('qty_received'), [4.0], 'Purchase: no conversion error on receipt in different uom"')
+
+    def test_message_qty_already_received(self):
+        _product = self.env['product.product'].create({
+            'name': 'TempProduct',
+            'type': 'consu',
+            'company_id': self.env.user.company_id.id,
+        })
+
+        _purchase_order = self.env['purchase.order'].create({
+            'company_id': self.env.user.company_id.id,
+            'partner_id': self.partner_a.id,
+            'order_line': [
+                (0, 0, {
+                    'name': _product.name,
+                    'product_id': _product.id,
+                    'product_qty': 25.0,
+                    'price_unit': 250.0,
+                })],
+        })
+
+        _purchase_order.button_confirm()
+
+        first_picking = _purchase_order.picking_ids[0]
+        first_picking.move_lines.quantity_done = 5
+        backorder_wizard_dict = first_picking.button_validate()
+        backorder_wizard = Form(self.env[backorder_wizard_dict['res_model']].with_context(backorder_wizard_dict['context'])).save()
+        backorder_wizard.process()
+
+        second_picking = _purchase_order.picking_ids[1]
+        second_picking.move_lines.quantity_done = 5
+        backorder_wizard_dict = second_picking.button_validate()
+        backorder_wizard = Form(self.env[backorder_wizard_dict['res_model']].with_context(backorder_wizard_dict['context'])).save()
+        backorder_wizard.process()
+
+        third_picking = _purchase_order.picking_ids[2]
+        third_picking.move_lines.quantity_done = 5
+        backorder_wizard_dict = third_picking.button_validate()
+        backorder_wizard = Form(self.env[backorder_wizard_dict['res_model']].with_context(backorder_wizard_dict['context'])).save()
+        backorder_wizard.process()
+
+        _message_content = _purchase_order.message_ids.mapped("body")[0]
+        self.assertIsNotNone(re.search(r"Received Quantity: 5.0 -> 10.0", _message_content), "Already received quantity isn't correctly taken into consideration")