[FIX] calendar: invitation for deleted event (recurring)

From calendar create a recursive event and add some guests. Delete one
event of the chain.

Invitations (Mail) will be created for the deleted event, and should not
be the case because the event has been deleted.

This happens because the recursive event is really just a record in the
database representing all the generated events. When the user want to
delete an event in the chain, a new event, copy of the "parent" event
has to be registered and subsequently disabled.
In the process of creating the event the mail is sent as
side effect. Note that the code to prevent this was partially there
because a context flag "dont_notify" is sent by the unlink in
Calendar.Meeting but was ignored from the mail subsystem.

opw-2039576

closes odoo/odoo#36270

Signed-off-by: Nans Lefebvre (len) <len@odoo.com>

addons/calendar/models/calendar.py

@@ -1065,11 +1065,13 @@ class Meeting(models.Model):
                 meeting_attendees |= attendee
                 meeting_partners |= partner
 
-            if meeting_attendees:
+            if meeting_attendees and not self._context.get('detaching'):
                 to_notify = meeting_attendees.filtered(lambda a: a.email != current_user.email)
                 to_notify._send_mail_to_attendees('calendar.calendar_template_meeting_invitation')
 
+            if meeting_attendees:
                 meeting.write({'attendee_ids': [(4, meeting_attendee.id) for meeting_attendee in meeting_attendees]})
+
             if meeting_partners:
                 meeting.message_subscribe(partner_ids=meeting_partners.ids)
 
@@ -1417,7 +1419,7 @@ class Meeting(models.Model):
             # do not copy the id
             if data.get('id'):
                 del data['id']
-            return meeting_origin.copy(default=data)
+            return meeting_origin.with_context(detaching=True).copy(default=data)
 
     @api.multi
     def action_detach_recurring_event(self):

addons/calendar/tests/test_calendar.py

@@ -7,6 +7,7 @@ from datetime import datetime, timedelta, time
 from odoo import fields
 from odoo.tests.common import TransactionCase
 import pytz
+import re
 
 
 class TestCalendar(TransactionCase):
@@ -384,3 +385,60 @@ class TestCalendar(TransactionCase):
         })
 
         self.assertEqual(str(activity_id.date_deadline), '2018-10-16')
+
+    def test_event_creation_mail(self):
+        """
+        Check that mail are sent to the attendees on event creation
+        Check that mail are sent to the added attendees on event edit
+        Check that mail are NOT sent to the attendees when detaching a recurring event
+        """
+
+        def _test_one_mail_per_attendee(self, m, partners):
+            # check that every attendee receive a (single) mail for the event
+            for partner in partners:
+                mail = self.env['mail.mail'].search([
+                    ('recipient_ids', 'in', partner.id),
+                    ('subject', 'like', m.name),
+                    ])
+                self.assertEqual(len(mail), 1)
+
+        partners = [
+           self.env['res.partner'].create({'name':'testuser0','email': u'bob@example.com'}),
+           self.env['res.partner'].create({'name':'testuser1','email': u'alice@example.com'}),
+           ]
+        partner_ids = [(6, False, [p.id for p in partners]),]
+        now = fields.Datetime.now()
+        m = self.CalendarEvent.create({
+            'name': "mailTest1",
+            'allday': False,
+            'rrule': u'FREQ=DAILY;INTERVAL=1;COUNT=5',
+            'duration': 0.5,
+            'partner_ids': partner_ids,
+            'start': fields.Datetime.to_string(now + timedelta(days=10)),
+            'stop': fields.Datetime.to_string(now + timedelta(days=15)),
+            })
+
+        # every partner should have 1 mail sent
+        _test_one_mail_per_attendee(self, m, partners)
+
+        # adding more partners to the event
+        partners.extend([
+            self.env['res.partner'].create({'name':'testuser2','email': u'marc@example.com'}),
+            self.env['res.partner'].create({'name':'testuser3','email': u'carl@example.com'}),
+            self.env['res.partner'].create({'name':'testuser4','email': u'alain@example.com'}),
+            ])
+        partner_ids = [(6, False, [p.id for p in partners]),]
+        m.write({'partner_ids': partner_ids})
+
+        # more email should be sent
+        _test_one_mail_per_attendee(self, m, partners)
+
+        # calculate virtualid to detach one event
+        virtid = str(m.id) + '-' + ''.join(re.split('[\D]', fields.Datetime.to_string(now + timedelta(days=12))))
+
+        # detaching a virtual event in the chain
+        self.env['calendar.event'].browse(virtid).detach_recurring_event(values={'active':False})
+
+        # since the detach actually create an event in the backend
+        # we check that no mail notifications are sent to the attendees
+        _test_one_mail_per_attendee(self, m, partners)