[FIX] purchase: hook to allow override of domain

Add a hook to allow the hardcoded domain in the method `make_po`, in
procurement order.

Base on work by @Cedric-Pigeon

opw-744606
Closes #17147

addons/purchase/models/purchase.py

@@ -988,6 +988,21 @@ class ProcurementOrder(models.Model):
         """
         return suppliers[0]
 
+    def _make_po_get_domain(self, partner):
+        gpo = self.rule_id.group_propagation_option
+        group = (gpo == 'fixed' and self.rule_id.group_id) or \
+                (gpo == 'propagate' and self.group_id) or False
+
+        domain = (
+            ('partner_id', '=', partner.id),
+            ('state', '=', 'draft'),
+            ('picking_type_id', '=', self.rule_id.picking_type_id.id),
+            ('company_id', '=', self.company_id.id),
+            ('dest_address_id', '=', self.partner_dest_id.id))
+        if group:
+            domain += (('group_id', '=', group.id),)
+        return domain
+
     @api.multi
     def make_po(self):
         cache = {}
@@ -1001,18 +1016,7 @@ class ProcurementOrder(models.Model):
             supplier = procurement._make_po_select_supplier(suppliers)
             partner = supplier.name
 
-            gpo = procurement.rule_id.group_propagation_option
-            group = (gpo == 'fixed' and procurement.rule_id.group_id) or \
-                    (gpo == 'propagate' and procurement.group_id) or False
-
-            domain = (
-                ('partner_id', '=', partner.id),
-                ('state', '=', 'draft'),
-                ('picking_type_id', '=', procurement.rule_id.picking_type_id.id),
-                ('company_id', '=', procurement.company_id.id),
-                ('dest_address_id', '=', procurement.partner_dest_id.id))
-            if group:
-                domain += (('group_id', '=', group.id),)
+            domain = procurement._make_po_get_domain(partner)
 
             if domain in cache:
                 po = cache[domain]