[FIX] {test_,}mail: don't copy alias_id for models using optional alias

Summary
-------
Currently, duplicating a journal results in the new journal's mail alias
name overwriting the original's.

Steps to reproduce
------------------
* install `account_accountant`
* duplicate the "Vendor Bills" journal

=> you should see that the alias name of the new journal overwrites the
alias of the original journal.

Cause
-----
When duplicating a journal, the new journal inherits the alias of the
original. Because of this, a specific code segment intended to generate
missing aliases for new sale/purchase journals, inadvertently modifies
the name of the alias.

opw-3597349

closes odoo/odoo#143771

Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>

addons/mail/models/mail_alias_mixin_optional.py

@@ -18,7 +18,7 @@ class AliasMixinOptional(models.AbstractModel):
     _description = 'Email Aliases Mixin (light)'
     ALIAS_WRITEABLE_FIELDS = ['alias_domain_id', 'alias_name', 'alias_contact', 'alias_defaults', 'alias_bounced_content']
 
-    alias_id = fields.Many2one('mail.alias', string='Alias', ondelete="restrict", required=False)
+    alias_id = fields.Many2one('mail.alias', string='Alias', ondelete="restrict", required=False, copy=False)
     alias_name = fields.Char(related='alias_id.alias_name', readonly=False)
     alias_domain_id = fields.Many2one(
         'mail.alias.domain', string='Alias Domain',

addons/test_mail/tests/test_mail_alias.py

@@ -807,6 +807,18 @@ class TestMailAliasMixin(TestMailAliasCommon):
         record_copy2 = record_copy.copy()
         self.assertEqual(record_copy2.alias_bounced_content, new_content)
 
+    @users('employee')
+    def test_copy_optional_alias_model(self):
+        """ Do not propagate alias_id to duplicate record as it could lead to
+        overwriting alias_name of old record. """
+        record = self.env['mail.test.alias.optional'].create({
+            'name': 'Test Optional Alias Record',
+            'alias_name': 'test.optional.alias.record',
+        })
+        self.assertTrue(record.alias_id)
+        record_copy = record.copy()
+        self.assertFalse(record_copy.alias_id)
+
     @users('erp_manager')
     def test_multi_company_setup(self):
         """ Test company impact on alias domains when creating or updating