[FIX] mail: notify guest when joining the channel

Before this PR, the guest that just connect wouldn't receive the longpolling
message before the current one expire.

task-2664831

closes odoo/odoo#82170

X-original-commit: 0006123dba46d32d062a581e9a16f433f3ce05f3
Signed-off-by: Sébastien Theys (seb) <seb@odoo.com>

addons/mail/models/mail_channel.py

@@ -360,6 +360,11 @@ class Channel(models.Model):
                     'id': channel_partner.guest_id.id,
                     'name': channel_partner.guest_id.name,
                 })
+                guest = channel_partner.guest_id
+                if guest:
+                    self.env['bus.bus']._sendone(guest, 'mail.channel/joined', {
+                        'channel': channel_partner.channel_id.sudo().channel_info()[0],
+                    })
             self.env['bus.bus']._sendone(channel, 'mail.channel/insert', {
                 'id': channel.id,
                 'guestMembers': [('insert', guest_members_data)],

addons/mail/static/src/models/messaging_notification_handler/messaging_notification_handler.js

@@ -182,11 +182,11 @@ registerModel({
          * @private
          * @param {Object} payload
          * @param {Thread} payload.channel
-         * @param {integer} payload.invited_by_user_id
+         * @param {integer} [payload.invited_by_user_id]
          */
         _handleNotificationChannelJoined({ channel: channelData, invited_by_user_id: invitedByUserId }) {
             const channel = this.messaging.models['Thread'].insert(this.messaging.models['Thread'].convertData(channelData));
-            if (invitedByUserId !== this.messaging.currentUser.id) {
+            if (this.messaging.currentUser && invitedByUserId !== this.messaging.currentUser.id) {
                 // Current user was invited by someone else.
                 this.env.services['notification'].notify({
                     message: _.str.sprintf(

addons/mail/tests/test_rtc.py

@@ -451,6 +451,7 @@ class TestChannelInternals(MailCommon):
                 (self.cr.dbname, 'res.partner', self.user_employee.partner_id.id),  # update of last interest (not asserted below)
                 (self.cr.dbname, 'res.partner', test_user.partner_id.id),  # update of last interest (not asserted below)
                 (self.cr.dbname, 'mail.channel', channel.id),  # new member (guest) (not asserted below)
+                (self.cr.dbname, 'mail.guest', test_guest.id), # channel joined for guest (not asserted below)
             ],
             [
                 {