[FIX] calendar: duplicated emails when creating allday meeting

Steps to reproduce:

  - Switch to debug mode
  - Go to calendar
  - Create an allday event in the future named test
  - Add an attendee with an email address
  - Save
  - Go to Settings > Technical > Email > Emails

  Two emails have been sent:
  * Invitation to test
  * test: Date updated

Cause of the issue:

  The method `_inverse_dates` is called when creating an event,
  triggering a write on the start field.
  This then causes an update email to be sent

Solution:

  Add a context key and don't send the update email if it is present

opw-2841276

closes odoo/odoo#100275

Signed-off-by: Arnaud Joset <arj@odoo.com>

addons/calendar/models/calendar_event.py

@@ -711,7 +711,7 @@ class Meeting(models.Model):
         current_attendees = self.filtered('active').attendee_ids
         if 'partner_ids' in values:
             (current_attendees - previous_attendees)._send_mail_to_attendees('calendar.calendar_template_meeting_invitation')
-        if 'start' in values:
+        if not self.env.context.get('is_calendar_event_new') and 'start' in values:
             start_date = fields.Datetime.to_datetime(values.get('start'))
             # Only notify on future events
             if start_date and start_date >= fields.Datetime.now():
@@ -721,6 +721,9 @@ class Meeting(models.Model):
 
     @api.model_create_multi
     def create(self, vals_list):
+        # Prevent sending update notification when _inverse_dates is called
+        self = self.with_context(is_calendar_event_new=True)
+
         vals_list = [  # Else bug with quick_create when we are filter on an other user
             dict(vals, user_id=self.env.user.id) if not 'user_id' in vals else vals
             for vals in vals_list
@@ -785,7 +788,7 @@ class Meeting(models.Model):
                 if len(event.alarm_ids) > 0:
                     self.env['calendar.alarm_manager']._notify_next_alarm(event.partner_ids.ids)
 
-        return events
+        return events.with_context(is_calendar_event_new=False)
 
     def _read(self, fields):
         if self.env.is_system():

addons/calendar/tests/test_event_notifications.py

@@ -30,6 +30,20 @@ class TestEventNotifications(SavepointCase, MailCase):
         }):
             self.event.partner_ids = self.partner
 
+    def test_message_invite_allday(self):
+        with self.assertSinglePostNotifications([{'partner': self.partner, 'type': 'inbox'}], {
+            'message_type': 'user_notification',
+            'subtype': 'mail.mt_note',
+        }):
+            self.env['calendar.event'].with_context(mail_create_nolog=True).create([{
+                'name': 'Meeting',
+                'allday': True,
+                'start_date': fields.Date.today() + relativedelta(days=7),
+                'stop_date': fields.Date.today() + relativedelta(days=8),
+                'partner_ids': [(4, self.partner.id)],
+            }])
+
+
     def test_message_invite_self(self):
         with self.assertNoNotifications():
             self.event.with_user(self.user).partner_ids = self.partner