[FIX] sale_purchase: service product preserve variant

Steps to reproduce:
-Install sale_purchase_stock and sale_product_matrix
-Have a Service product that is subcontracted.
-Set a variant with a Specification Attribute that has a custom value.
-Create a sales order with the Service product,
add anything for the specification in the variant.
-Confirm the order, this generates a PO.

Bug:
The PO line only says the name of the product,
and doesn't include the specification in the variant.

Fix:
propagate the description same as:
"_prepare_procurement_values" and "_prepare_purchase_order_line_from_procurement"

opw-3438125

closes odoo/odoo#138310

X-original-commit: 5b3bcee8f7308621608d91e33bac808586e8c17f
Signed-off-by: Walid Hanniche (waha) <waha@odoo.com>
Signed-off-by: Quentin Wolfs (quwo) <quwo@odoo.com>

addons/sale_purchase/models/sale_order_line.py

@@ -197,6 +197,10 @@ class SaleOrderLine(models.Model):
         price_unit, taxes = self._purchase_service_get_price_unit_and_taxes(supplierinfo, purchase_order)
         name = self._purchase_service_get_product_name(supplierinfo, purchase_order, quantity)
 
+        line_description = self.with_context(lang=self.order_id.partner_id.lang)._get_sale_order_line_multiline_description_variants()
+        if line_description:
+            name += line_description
+
         return {
             'name': name,
             'product_qty': purchase_qty_uom,

addons/sale_purchase/tests/test_sale_purchase.py

@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
+from odoo import Command
 from odoo.exceptions import UserError, AccessError
 from odoo.tests import tagged
 from odoo.addons.sale_purchase.tests.common import TestCommonSalePurchaseNoChart
@@ -258,3 +259,49 @@ class TestSalePurchase(TestCommonSalePurchaseNoChart):
 
         po = self.env['purchase.order'].search([('partner_id', '=', self.partner_vendor_service.id)], order='id desc', limit=1)
         self.assertEqual(po.order_line.name, "[C01] Name01")
+
+    def test_pol_custom_attribute(self):
+        """
+         test that custom atributes are passed from the SO the PO for service products
+        """
+        # Setup service product variants
+        product_attribute = self.env['product.attribute'].create({
+            'name': 'product attribute',
+            'display_type': 'radio',
+            'create_variant': 'always'
+        })
+
+        product_attribute_value = self.env['product.attribute.value'].create({
+            'name': 'single product attribute value',
+            'is_custom': True,
+            'attribute_id': product_attribute.id
+        })
+
+        product_attribute_line = self.env['product.template.attribute.line'].create({
+            'attribute_id': product_attribute.id,
+            'product_tmpl_id': self.service_purchase_1.product_tmpl_id.id,
+            'value_ids': [Command.link(product_attribute_value.id)]
+        })
+
+        custom_value = "test"
+
+        # create and confirm SO
+        sale_order = self.env['sale.order'].create({
+            'partner_id': self.partner_a.id,
+            'order_line': [
+                Command.create({
+                    'name': self.service_purchase_1.name,
+                    'product_id': self.service_purchase_1.id,
+                    'product_uom_qty': 1,
+                    'product_custom_attribute_value_ids': [
+                        Command.create({
+                            'custom_product_template_attribute_value_id': product_attribute_line.product_template_value_ids.id,
+                            'custom_value': custom_value,
+                        })
+                    ],
+                })
+            ],
+        })
+        sale_order.action_confirm()
+        pol = sale_order._get_purchase_orders().order_line
+        self.assertEqual(pol.name, f"{self.service_purchase_1.display_name}\n\n{product_attribute.name}: {product_attribute_value.name}: {custom_value}")