[FIX] mrp_subcontracting_dropshipping: dropship twice from same vendor

To reproduce the issue:
1. In Settings, enable "Multi-Step Routes"
2. Edit the route "Dropship Subcontractor on Order":
   - Open the Buy rule:
     - Propagation of Procurement Group: Leave Empty
3. Create three products P1, P2, P_comp:
   - Storable
   - With a vendor (V1, V2, V_comp)
   - P_comp's routes:
     - Dropship Subcontractor on Order
4. Create a BoM:
   - Product: P1
   - Type: Subcontracting
   - Subcontractors: V1
   - Components: 1 x P_comp
5. Repeat step 4 with P2 and V2
6. Create and confirm a PO:
   - Vendor: V1
   - Products: 1 x P1
7. Repeat step 6 with V2 and P2
8. Open the purchase orders list

Error: There is only one PO with V_comp. It contains 2 x P_comp and
the dropship address is P1. This is incorrect. There should be two
PO, one for P1 and another one for P2

When confirming the PO, a MO is created (subcontracted) and then the
system creates and processes a procurement for the component.
Because of the component's routes, it leads to the `_run_buy` method.
It will check whether a PO already exists or has to be created. To do
so, it creates a domain based on few criteria, such as the value of
`dest_address_id`:
https://github.com/odoo/odoo/blob/6d28c9c2e5ea3e9a3b8a872627a411bbfe2f2a59/addons/mrp_subcontracting_dropshipping/models/stock_rule.py#L17-L21
But here is the issue: `partner_id` is not defined.

OPW-3370648

closes odoo#128791

X-original-commit: 094e45d
Signed-off-by: William Henrotin (whe) <[email protected]>
Signed-off-by: Adrien Widart (awt) <[email protected]>

addons/mrp_subcontracting_dropshipping/models/stock_move.py

@@ -7,6 +7,13 @@
 class StockMove(models.Model):
     _inherit = "stock.move"
 
+    def _prepare_procurement_values(self):
+        vals = super()._prepare_procurement_values()
+        partner = self.group_id.partner_id
+        if not vals.get('partner_id') and partner and self.location_id.is_subcontracting_location:
+            vals['partner_id'] = partner.id
+        return vals
+
     def _is_purchase_return(self):
         res = super()._is_purchase_return()
         return res or self._is_dropshipped_returned()

addons/mrp_subcontracting_dropshipping/tests/test_purchase_subcontracting.py

@@ -347,3 +347,55 @@ def test_po_to_subcontractor(self):
         delivery.button_validate()
 
         self.assertEqual(po.order_line.qty_received, 1.0)
+
+    def test_two_boms_same_component_supplier(self):
+        """
+        The "Dropship Subcontractor" route is modified: the propagation of the
+        buy rule is set to "Leave Empty".
+        Two subcontracted products (different subcontractor) that use the same
+        component. The component has its own supplier. Confirm one PO for each
+        subcontrated product. It should generate two PO from component's
+        supplier to each subcontractor.
+        """
+        dropship_subcontractor_route = self.env.ref('mrp_subcontracting_dropshipping.route_subcontracting_dropshipping')
+        dropship_subcontractor_route.rule_ids.filtered(lambda r: r.action == 'buy').group_propagation_option = 'none'
+
+        subcontractor01, subcontractor02, component_supplier = self.env['res.partner'].create([{
+            'name': 'Super Partner %d' % i
+        } for i in range(3)])
+
+        product01, product02, component = self.env['product.product'].create([{
+            'name': name,
+            'type': 'product',
+            'seller_ids': [(0, 0, {'partner_id': vendor.id})],
+            'route_ids': [(6, 0, routes)],
+        } for name, vendor, routes in [
+            ('SuperProduct 01', subcontractor01, []),
+            ('SuperProduct 02', subcontractor02, []),
+            ('Component', component_supplier, dropship_subcontractor_route.ids),
+        ]])
+
+        self.env['mrp.bom'].create([{
+            'product_tmpl_id': finished.product_tmpl_id.id,
+            'type': 'subcontract',
+            'subcontractor_ids': [(4, subcontractor.id)],
+            'bom_line_ids': [(0, 0, {'product_id': component.id})]
+        } for finished, subcontractor in [
+            (product01, subcontractor01),
+            (product02, subcontractor02),
+        ]])
+
+        for (partner, product) in [(subcontractor01, product01), (subcontractor02, product02)]:
+            po_form = Form(self.env['purchase.order'])
+            po_form.partner_id = partner
+            with po_form.order_line.new() as line:
+                line.product_id = product
+            po = po_form.save()
+            po.button_confirm()
+
+        supplier_orders = self.env['purchase.order'].search([('partner_id', '=', component_supplier.id)])
+        self.assertEqual(supplier_orders.dest_address_id, subcontractor01 | subcontractor02)
+        self.assertRecordValues(supplier_orders.order_line, [
+            {'product_id': component.id, 'product_qty': 1.0},
+            {'product_id': component.id, 'product_qty': 1.0},
+        ])