[FIX] mail: unicode character in email cannot be parsed

Sending email to addresses containing unicode characters
cannot be parsed by python and result in a UnicodeEncodeError.

This PR catch that specific exception and output a meaningful
error message.

Decision has been taken to not trigger any error message
client-side has it would have needed modifications on some
sensitive low-level backend code.

To reproduce:
- Configure odoo so it uses an email server
- Send an invoice to a partner whoose email address contains
some unicode characters (exemple: æøåÇÀ@example.com)

opw-1892409

closes odoo/odoo#27804

addons/mail/models/mail_mail.py

@@ -358,6 +358,9 @@ class MailMail(models.Model):
                     # /!\ can't use mail.state here, as mail.refresh() will cause an error
                     # see revid:odo@openerp.com-20120622152536-42b2s28lvdv3odyr in 6.1
                 mail._postprocess_sent_message(success_pids=success_pids, failure_type=failure_type)
+            except UnicodeEncodeError as exc:
+                _logger.exception('UnicodeEncodeError on text "%s" while processing mail ID %r.', exc.object, mail.id)
+                raise MailDeliveryException(_("Mail Delivery Failed"), "Invalid text: %s" % exc.object)
             except MemoryError:
                 # prevent catching transient MemoryErrors, bubble up to notify user or abort cron job
                 # instead of marking the mail as failed

addons/test_mail/tests/test_mail_mail.py

@@ -6,6 +6,7 @@ import itertools
 from odoo.addons.test_mail.tests import common as mail_common
 from odoo.tests import common
 from odoo.tools import mute_logger
+from odoo.addons.base.models.ir_mail_server import MailDeliveryException
 
 
 class TestMail(common.SavepointCase, mail_common.MockEmails):
@@ -43,3 +44,13 @@ class TestMail(common.SavepointCase, mail_common.MockEmails):
         self.email_to_list.extend(itertools.chain.from_iterable(sent_email['email_to'] for sent_email in self._mails if sent_email.get('email_to')))
         self.assertNotIn(u'Ernest Employee <e.e@example.com>', self.email_to_list)
         self.assertIn(u'test@example.com', self.email_to_list)
+
+    @mute_logger('odoo.addons.mail.models.mail_mail')
+    def test_mail_message_values_unicode(self):
+        mail = self.env['mail.mail'].create({
+            'body_html': '<p>Test</p>',
+            'email_to': 'test.😊@example.com',
+            'partner_ids': [(4, self.user_employee.partner_id.id)]
+        })
+
+        self.assertRaises(MailDeliveryException, mail.send)