Prefix notification emails with the event slug

src/pretix/base/services/notifications.py

@@ -104,7 +104,11 @@ def send_notification_mail(notification: Notification, user: User):
 
     mail_send_task.apply_async(kwargs={
         'to': [user.email],
-        'subject': '[{}] {}'.format(settings.PRETIX_INSTANCE_NAME, notification.title),
+        'subject': '[{}] {}: {}'.format(
+            settings.PRETIX_INSTANCE_NAME,
+            notification.event.settings.mail_prefix or notification.event.slug.upper(),
+            notification.title
+        ),
         'body': body_plain,
         'html': body_html,
         'sender': settings.MAIL_FROM,

src/pretix/base/services/tickets.py

@@ -145,7 +145,7 @@ def get_tickets_for_order(order):
                         retval = generate_orderposition(pos.pk, p.identifier)
                         if not retval:
                             continue
-                        ct = CachedCombinedTicket.objects.get(pk=retval)
+                        ct = CachedTicket.objects.get(pk=retval)
                     tickets.append((
                         "{}-{}-{}-{}{}".format(
                             order.event.slug.upper(), order.code, pos.positionid, ct.provider, ct.extension,