[FIX] mail: avoid sending mail when creating record from data

Before this fix the creation of task assigned to admin was leading
to the creation of mails.

This is a generic fix to avoid to notifiy a user when he is add as a
follower when creating data from odoo data files.

closes odoo/odoo#27682

addons/mail/models/mail_thread.py

@@ -2339,6 +2339,8 @@ class MailThread(models.AbstractModel):
         """
         if not self or self.env.context.get('mail_auto_subscribe_no_notify'):
             return
+        if not self.env.registry.ready:  # Don't send notification during install
+            return
 
         view = self.env['ir.ui.view'].browse(self.env['ir.model.data'].xmlid_to_res_id(template))
 

addons/test_mail/tests/test_performance.py

@@ -361,6 +361,7 @@ class TestHeavyMailPerformance(TransactionCase):
             self.env.ref('mail.mt_comment').id,
             self.env.ref('test_mail.st_mail_test_child_full').id]
         )
+        self.patch(self.env.registry, 'ready', True)
 
     @mute_logger('odoo.tests', 'odoo.addons.mail.models.mail_mail', 'odoo.models.unlink')
     @users('__system__', 'emp')
@@ -595,7 +596,7 @@ class TestHeavyMailPerformance(TransactionCase):
     def test_complex_tracking_template(self):
         """ Write performance test involving assignation, tracking with template """
         customer_id = self.customer.id
-
+        self.assertTrue(self.env.registry.ready, "We need to simulate that registery is ready")
         rec = self.env['mail.test.full'].create({
             'name': 'Test',
             'umbrella_id': self.umbrella.id,