[FIX] partner_ref_unique: Trigger check on company update

Before this commit, the partner_ref_unique could be changed on the
company even if existing partners share the same internal ref.

Therefore, errors will appear afterwards as DB already contains
duplicates although the policy shouldn't allow it.

With this change, the error will appear as soon as the policy is
changed, so that the data must be fixed before activating the
constraint.

partner_ref_unique/__manifest__.py

@@ -5,7 +5,7 @@
 {
     "name": "Partner unique reference",
     "summary": "Add an unique constraint to partner ref field",
-    "version": "12.0.1.0.0",
+    "version": "12.0.1.0.1",
     "category": "Customer Relationship Management",
     "website": "https://github.com/OCA/partner-contact/",
     "author": "Tecnativa, "

partner_ref_unique/models/res_partner.py

@@ -1,18 +1,24 @@
 # Copyright 2016 Antonio Espinosa
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
 
-from odoo import _, api, models
+from odoo import _, api, fields, models
 from odoo.exceptions import ValidationError
 
 
 class ResPartner(models.Model):
     _inherit = "res.partner"
 
+    # This related is needed in order to trigger the check when changing the
+    # value on res.company
+    partner_ref_unique = fields.Selection(
+        related='company_id.partner_ref_unique',
+    )
+
     @api.multi
-    @api.constrains('ref', 'is_company', 'company_id')
+    @api.constrains('ref', 'is_company', 'company_id', 'partner_ref_unique')
     def _check_ref(self):
         for partner in self:
-            mode = partner.company_id.partner_ref_unique
+            mode = partner.partner_ref_unique
             if (partner.ref and (
                     mode == 'all' or
                     (mode == 'companies' and partner.is_company))):

partner_ref_unique/tests/test_res_partner_ref.py

@@ -18,7 +18,7 @@ class TestResPartnerRefUnique(common.SavepointCase):
             'name': 'Partner2',
         })
 
-    def test_check_ref(self):
+    def test_check_ref_company(self):
         # Test can create/modify partners with same ref
         self.company.partner_ref_unique = 'none'
         self.partner1.ref = 'same_ref'
@@ -30,6 +30,11 @@ class TestResPartnerRefUnique(common.SavepointCase):
             'ref': 'same_ref',
         })
         self.partner2.ref = False
+        with self.assertRaises(ValidationError):
+            self.company.partner_ref_unique = 'all'
+
+    def test_check_ref(self):
+        self.partner1.ref = 'same_ref'
         # Test can't create/modify partner with same ref
         self.company.partner_ref_unique = 'all'
         with self.assertRaises(ValidationError):