[FIX] mail: avoid sending notif when not needed

When there is no channel members to be updated the seen status, we
should not send a notification to the channel members, otherwise it
will lead into creating a channel member with id undefined.

test case added to check that the notification is not sent when there
is no channel members to be updated.

closes odoo/odoo#156534

Signed-off-by: Sébastien Theys (seb) <seb@odoo.com>

addons/mail/models/discuss/discuss_channel.py

@@ -1045,6 +1045,8 @@ class Channel(models.Model):
             ])
         ])
         member = self.env['discuss.channel.member'].search(channel_member_domain)
+        if not member:
+            return
         member.write({
             'fetched_message_id': max(member.fetched_message_id.id, last_message.id),
             'seen_message_id': last_message.id,

addons/mail/tests/discuss/test_discuss_channel.py

@@ -199,6 +199,31 @@ class TestChannelInternals(MailCommon):
             "Last message id should stay the same after mark channel as seen with an older message"
         )
 
+    @users('employee')
+    def test_set_last_seen_message_should_send_notification_only_once(self):
+        chat = self.env['discuss.channel'].with_user(self.user_admin).channel_get((self.partner_employee | self.user_admin.partner_id).ids)
+        msg_1 = self._add_messages(chat, 'Body1', author=self.user_employee.partner_id)
+
+        self.env['bus.bus'].sudo().search([]).unlink()
+        with self.assertBus(
+            [(self.env.cr.dbname, "discuss.channel", chat.id)],
+            [{
+                "type": "discuss.channel.member/seen",
+                "payload": {
+                    'channel_id': chat.id,
+                    'id': chat.channel_member_ids.filtered(lambda m: m.partner_id == self.user_admin.partner_id).id,
+                    'last_message_id': msg_1.id,
+                    'partner_id': self.user_admin.partner_id.id,
+                },
+            }],
+        ):
+            chat._channel_seen(msg_1.id)
+        # There should be no channel member to be set as seen in the second time
+        # So no notification should be sent
+        self.env['bus.bus'].sudo().search([]).unlink()
+        with self.assertBus([], []):
+            chat._channel_seen(msg_1.id)
+
     def test_channel_message_post_should_not_allow_adding_wrong_parent(self):
         channels = self.env['discuss.channel'].create([{'name': '1'}, {'name': '2'}])
         message = self._add_messages(channels[0], 'Body1')