[FIX] partner_vat_unique: Do not copy vat field

partner_vat_unique/i18n/partner_vat_unique.pot

@@ -19,7 +19,19 @@ msgid "Contact"
 msgstr ""
 
 #. module: partner_vat_unique
-#: code:addons/partner_vat_unique/models/res_partner.py:27
+#: model:ir.model.fields,field_description:partner_vat_unique.field_res_partner__vat
+#: model:ir.model.fields,field_description:partner_vat_unique.field_res_users__vat
+msgid "Tax ID"
+msgstr ""
+
+#. module: partner_vat_unique
+#: model:ir.model.fields,help:partner_vat_unique.field_res_partner__vat
+#: model:ir.model.fields,help:partner_vat_unique.field_res_users__vat
+msgid "The Tax Identification Number. Complete it if the contact is subjected to government taxes. Used in some legal statements."
+msgstr ""
+
+#. module: partner_vat_unique
+#: code:addons/partner_vat_unique/models/res_partner.py:29
 #, python-format
 msgid "The VAT %s already exists in another partner."
 msgstr ""

partner_vat_unique/models/res_partner.py

@@ -1,7 +1,7 @@
 # Copyright 2017 Grant Thornton Spain - Ismael Calvo <ismael.calvo@es.gt.com>
 # 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
 from odoo.tools import config
 
@@ -9,6 +9,8 @@ from odoo.tools import config
 class ResPartner(models.Model):
     _inherit = 'res.partner'
 
+    vat = fields.Char(copy=False)
+
     @api.constrains('vat')
     def _check_vat_unique(self):
         for record in self:

partner_vat_unique/tests/test_vat_unique.py

@@ -21,3 +21,7 @@ class TestVatUnique(SavepointCase):
                 'name': 'Second partner',
                 'vat': 'ESA12345674'
             })
+
+    def test_duplicate_partner(self):
+        partner_copied = self.partner.copy()
+        self.assertFalse(partner_copied.vat)