tests, comments

src/pretix/base/migrations/0297_outgoingmail.py

@@ -1,9 +1,11 @@
-# Generated by Django 4.2.17 on 2025-09-04 12:35
+# Generated by Django 4.2.26 on 2026-01-22 13:44
 
 import django.db.models.deletion
 from django.conf import settings
 from django.db import migrations, models
 
+import pretix.base.models.mail
+
 
 class Migration(migrations.Migration):
 
@@ -24,6 +26,8 @@ class Migration(migrations.Migration):
                 ("status", models.CharField(default="queued", max_length=200)),
                 ("created", models.DateTimeField(auto_now_add=True)),
                 ("sent", models.DateTimeField(blank=True, null=True)),
+                ("inflight_since", models.DateTimeField(blank=True, null=True)),
+                ("retry_after", models.DateTimeField(blank=True, null=True)),
                 ("error", models.TextField(null=True)),
                 ("error_detail", models.TextField(null=True)),
                 ("subject", models.TextField()),
@@ -42,7 +46,7 @@ class Migration(migrations.Migration):
                     "customer",
                     models.ForeignKey(
                         null=True,
-                        on_delete=django.db.models.deletion.SET_NULL,
+                        on_delete=pretix.base.models.mail.CASCADE_IF_QUEUED,
                         related_name="outgoing_mails",
                         to="pretixbase.customer",
                     ),
@@ -51,7 +55,7 @@ class Migration(migrations.Migration):
                     "event",
                     models.ForeignKey(
                         null=True,
-                        on_delete=django.db.models.deletion.SET_NULL,
+                        on_delete=pretix.base.models.mail.CASCADE_IF_QUEUED,
                         related_name="outgoing_mails",
                         to="pretixbase.event",
                     ),
@@ -60,7 +64,7 @@ class Migration(migrations.Migration):
                     "order",
                     models.ForeignKey(
                         null=True,
-                        on_delete=django.db.models.deletion.SET_NULL,
+                        on_delete=pretix.base.models.mail.CASCADE_IF_QUEUED,
                         related_name="outgoing_mails",
                         to="pretixbase.order",
                     ),
@@ -69,7 +73,7 @@ class Migration(migrations.Migration):
                     "orderposition",
                     models.ForeignKey(
                         null=True,
-                        on_delete=django.db.models.deletion.SET_NULL,
+                        on_delete=pretix.base.models.mail.CASCADE_IF_QUEUED,
                         related_name="outgoing_mails",
                         to="pretixbase.orderposition",
                     ),
@@ -99,7 +103,7 @@ class Migration(migrations.Migration):
                     "user",
                     models.ForeignKey(
                         null=True,
-                        on_delete=django.db.models.deletion.SET_NULL,
+                        on_delete=django.db.models.deletion.CASCADE,
                         related_name="outgoing_mails",
                         to=settings.AUTH_USER_MODEL,
                     ),

src/pretix/base/models/mail.py

@@ -25,6 +25,19 @@ from django.utils.translation import gettext_lazy as _
 from django_scopes import scope, scopes_disabled
 
 
+def CASCADE_IF_QUEUED(collector, field, sub_objs, using):
+    # If the email is still queued and the thing it is related to vanishes, the email can vanish as well
+    print(sub_objs)
+    cascade_objs = [
+        o for o in sub_objs if o.status == OutgoingMail.STATUS_QUEUED
+    ]
+    if cascade_objs:
+        models.CASCADE(collector, field, cascade_objs, using)
+
+    # In all other cases, set to NULL to keep the email on record
+    models.SET_NULL(collector, field, [o for o in sub_objs if o not in cascade_objs], using)
+
+
 class OutgoingMail(models.Model):
     STATUS_QUEUED = "queued"
     STATUS_INFLIGHT = "inflight"
@@ -42,9 +55,23 @@ class OutgoingMail(models.Model):
     status = models.CharField(max_length=200, choices=STATUS_CHOICES, default=STATUS_QUEUED)
     created = models.DateTimeField(auto_now_add=True)
     sent = models.DateTimeField(null=True, blank=True)
+    inflight_since = models.DateTimeField(null=True, blank=True)
+    retry_after = models.DateTimeField(null=True, blank=True)
     error = models.TextField(null=True, blank=True)
     error_detail = models.TextField(null=True, blank=True)
 
+    # There is a conflict here between the different purposes of the model. As a system administrator,
+    # one wants *all* emails to be persisted as long as possible to debug issues. This means that if
+    # e.g. the event or order is deleted, we want SET_NULL behavior. However, in that case, the email
+    # would be an "orphan" forever and there's no way to remove the personal information.
+    # We try to find a middle-ground with the following behaviour:
+    # - The email is always deleted if the entire organize or user is deleted
+    # - The email is always deleted if it has not yet been sent
+    # - The email is kept in all other cases
+    # This is only an acceptable trade-off since emails are stored for a short period only, and because
+    # orders and customers are never deleted during normal operation. If we ever make this a long-term
+    # storage / email archive, we'd need to find another way to make sure personal information is removed
+    # if personal information of orders etc is removed.
     organizer = models.ForeignKey(
         'pretixbase.Organizer',
         on_delete=models.CASCADE,
@@ -53,31 +80,31 @@ class OutgoingMail(models.Model):
     )
     event = models.ForeignKey(
         'pretixbase.Event',
-        on_delete=models.SET_NULL,  # todo think, only for non-queued!
+        on_delete=CASCADE_IF_QUEUED,
         related_name='outgoing_mails',
         null=True, blank=True,
     )
     order = models.ForeignKey(
         'pretixbase.Order',
-        on_delete=models.SET_NULL,
+        on_delete=CASCADE_IF_QUEUED,
         related_name='outgoing_mails',
         null=True, blank=True,
     )
     orderposition = models.ForeignKey(
         'pretixbase.OrderPosition',
-        on_delete=models.SET_NULL,
+        on_delete=CASCADE_IF_QUEUED,
         related_name='outgoing_mails',
         null=True, blank=True,
     )
     customer = models.ForeignKey(
         'pretixbase.Customer',
-        on_delete=models.SET_NULL,
+        on_delete=CASCADE_IF_QUEUED,
         related_name='outgoing_mails',
         null=True, blank=True,
     )
     user = models.ForeignKey(
         'pretixbase.User',
-        on_delete=models.SET_NULL,
+        on_delete=models.CASCADE,
         related_name='outgoing_mails',
         null=True, blank=True,
     )
@@ -91,17 +118,25 @@ class OutgoingMail(models.Model):
     cc = models.JSONField(default=list)
     bcc = models.JSONField(default=list)
 
+    # We don't store the actual invoices, tickets or calendar invites, so if the email is re-sent at a later time, a
+    # newer version of the files might be used. We accept that risk to save on storage and also because the new
+    # version might actually be more useful.
     should_attach_invoices = models.ManyToManyField(
         'pretixbase.Invoice',
         related_name='outgoing_mails'
     )
     should_attach_tickets = models.BooleanField(default=False)
     should_attach_ical = models.BooleanField(default=False)
+
+    # We need to make sure cached files are kept as l
     should_attach_cached_files = models.ManyToManyField(
         'pretixbase.CachedFile',
         related_name='outgoing_mails',
     )  # todo: prevent deletion?
-    should_attach_other_files = models.JSONField(default=list)  # todo_ prevent deletion?
+
+    # This is used to send files stored in settings. In most cases, these aren't short-lived and should still be there
+    # if the email is sent. Otherwise, they will be skipped. We accept that risk.
+    should_attach_other_files = models.JSONField(default=list)
 
     actual_attachments = models.JSONField(default=list)
 

src/pretix/base/services/mail.py

@@ -40,6 +40,7 @@ import os
 import re
 import smtplib
 import warnings
+from datetime import timedelta
 from email.mime.image import MIMEImage
 from email.utils import formataddr
 from typing import Any, Dict, Optional, Sequence, Union
@@ -354,15 +355,20 @@ class CustomEmail(EmailMultiAlternatives):
 @app.task(base=TransactionAwareTask, bind=True, acks_late=True)
 def mail_send_task(self, *args, outgoing_mail: int) -> bool:
     with transaction.atomic():
-        outgoing_mail = OutgoingMail.objects.select_for_update(of=OF_SELF).get(pk=outgoing_mail)
+        try:
+            outgoing_mail = OutgoingMail.objects.select_for_update(of=OF_SELF).get(pk=outgoing_mail)
+        except OutgoingMail.DoesNotExist:
+            logger.info(f"Ignoring job for non existing email {outgoing_mail}")
+            return False
         if outgoing_mail.status == OutgoingMail.STATUS_INFLIGHT:
-            logger.info("Ignoring job for inflight email")
+            logger.info(f"Ignoring job for inflight email {outgoing_mail.pk}")
             return False
         elif outgoing_mail.status in (OutgoingMail.STATUS_SENT, OutgoingMail.STATUS_FAILED):
-            logger.info(f"Ignoring job for email in final state {outgoing_mail.status}")
+            logger.info(f"Ignoring job for email {outgoing_mail.pk} in final state {outgoing_mail.status}")
             return False
         outgoing_mail.status = OutgoingMail.STATUS_INFLIGHT
-        outgoing_mail.save(update_fields=["status"])
+        outgoing_mail.inflight_since = now()
+        outgoing_mail.save(update_fields=["status", "inflight_since"])
 
     email = CustomEmail(
         subject=outgoing_mail.subject,
@@ -405,7 +411,7 @@ def mail_send_task(self, *args, outgoing_mail: int) -> bool:
                         except MaxRetriesExceededError:
                             # Well then, something is really wrong, let's send it without attachment before we
                             # don't sent at all
-                            logger.exception('Could not attach tickets to email')
+                            logger.exception(f'Could not attach tickets to email {outgoing_mail.pk}')
                             pass
 
                 if attach_size * 1.37 < settings.FILE_UPLOAD_MAX_SIZE_EMAIL_ATTACHMENT - 1024 * 1024:
@@ -464,7 +470,7 @@ def mail_send_task(self, *args, outgoing_mail: int) -> bool:
                         )
                     invoices_attached.append(inv)
                 except Exception:
-                    logger.exception('Could not attach invoice to email')
+                    logger.exception(f'Could not attach invoice to email {outgoing_mail.pk}')
                     pass
                 else:
                     if inv.transmission_type == "email":
@@ -494,7 +500,7 @@ def mail_send_task(self, *args, outgoing_mail: int) -> bool:
                     ftype
                 )
             except:
-                logger.exception('Could not attach file to email')
+                logger.exception(f'Could not attach file to email {outgoing_mail.pk}')
                 pass
 
         for cf in outgoing_mail.should_attach_cached_files.all():
@@ -506,7 +512,7 @@ def mail_send_task(self, *args, outgoing_mail: int) -> bool:
                         cf.type,
                     )
                 except:
-                    logger.exception('Could not attach file to email')
+                    logger.exception(f'Could not attach file to email {outgoing_mail.pk}')
                     pass
 
         if outgoing_mail.event:
@@ -532,7 +538,7 @@ def mail_send_task(self, *args, outgoing_mail: int) -> bool:
         try:
             backend.send_messages([email])
         except Exception as e:
-            logger.exception('Error sending email')
+            logger.exception(f'Error sending email {outgoing_mail.pk}')
             retry_strategy = _retry_strategy(e)
             err, err_detail = _format_error(e)
 
@@ -554,19 +560,23 @@ def mail_send_task(self, *args, outgoing_mail: int) -> bool:
                     retry_after = min(30 + cnt * 10, 1800)
 
                     outgoing_mail.status = OutgoingMail.STATUS_AWAWITING_RETRY
-                    outgoing_mail.save(update_fields=["status", "error", "error_detail", "sent"])
+                    outgoing_mail.retry_after = now() + timedelta(seconds=retry_after)
+                    outgoing_mail.save(update_fields=["status", "error", "error_detail", "sent", "retry_after"])
                     self.retry(max_retries=max_retries, countdown=retry_after)  # throws RetryException, ends function flow
                 elif retry_strategy in ("microsoft_concurrency", "quick"):
                     max_retries = 5
                     retry_after = [10, 30, 60, 300, 900, 900][self.request.retries]
                     outgoing_mail.status = OutgoingMail.STATUS_AWAWITING_RETRY
-                    outgoing_mail.save(update_fields=["status", "error", "error_detail", "sent"])
+                    outgoing_mail.retry_after = now() + timedelta(seconds=retry_after)
+                    outgoing_mail.save(update_fields=["status", "error", "error_detail", "sent", "retry_after"])
                     self.retry(max_retries=max_retries, countdown=retry_after)  # throws RetryException, ends function flow
 
                 elif retry_strategy == "slow":
+                    retry_after = [60, 300, 600, 1200, 1800, 1800][self.request.retries]
                     outgoing_mail.status = OutgoingMail.STATUS_AWAWITING_RETRY
-                    outgoing_mail.save(update_fields=["status", "error", "error_detail", "sent"])
-                    self.retry(max_retries=5, countdown=[60, 300, 600, 1200, 1800, 1800][self.request.retries])  # throws RetryException, ends function flow
+                    outgoing_mail.retry_after = now() + timedelta(seconds=retry_after)
+                    outgoing_mail.save(update_fields=["status", "error", "error_detail", "sent", "retry_after"])
+                    self.retry(max_retries=5, countdown=retry_after)  # throws RetryException, ends function flow
 
             except MaxRetriesExceededError:
                 for i in invoices_to_mark_transmitted:
@@ -586,12 +596,18 @@ def mail_send_task(self, *args, outgoing_mail: int) -> bool:
                             'invoices': [],
                         }
                     )
+
+                outgoing_mail.status = OutgoingMail.STATUS_FAILED
+                outgoing_mail.sent = now()
+                outgoing_mail.retry_after = None
+                outgoing_mail.save(update_fields=["status", "error", "error_detail", "sent", "retry_after"])
                 return False
 
             # If we reach this, it's a non-retryable error
             outgoing_mail.status = OutgoingMail.STATUS_FAILED
             outgoing_mail.sent = now()
-            outgoing_mail.save(update_fields=["status", "error", "error_detail", "sent"])
+            outgoing_mail.retry_after = None
+            outgoing_mail.save(update_fields=["status", "error", "error_detail", "sent", "retry_after"])
             for i in invoices_to_mark_transmitted:
                 i.set_transmission_failed(provider="email_pdf", data={
                     "reason": "exception",
@@ -615,7 +631,8 @@ def mail_send_task(self, *args, outgoing_mail: int) -> bool:
             outgoing_mail.error_detail = None
             outgoing_mail.actual_attachments = actual_attachments
             outgoing_mail.sent = now()
-            outgoing_mail.save(update_fields=["status", "error", "error_detail", "sent", "actual_attachments"])
+            outgoing_mail.retry_after = None
+            outgoing_mail.save(update_fields=["status", "error", "error_detail", "sent", "actual_attachments", "retry_after"])
             for i in invoices_to_mark_transmitted:
                 if i.transmission_status != Invoice.TRANSMISSION_STATUS_COMPLETED:
                     i.transmission_date = now()

src/pretix/testutils/mail.py

@@ -29,3 +29,8 @@ class FailingEmailBackend(EmailBackend):
         raise smtplib.SMTPRecipientsRefused({
             'recipient@example.org': (450, b'Recipient unknown')
         })
+
+
+class PermanentlyFailingEmailBackend(EmailBackend):
+    def send_messages(self, email_messages):
+        raise smtplib.SMTPNotSupportedError()

src/tests/base/test_mail.py

@@ -39,14 +39,15 @@ from email.mime.text import MIMEText
 import pytest
 from django.conf import settings
 from django.core import mail as djmail
+from django.test import override_settings
 from django.utils.timezone import now
 from django.utils.translation import gettext_lazy as _
 from django_scopes import scope
 from i18nfield.strings import LazyI18nString
 
 from pretix.base.email import get_email_context
-from pretix.base.models import Event, Organizer, User
-from pretix.base.services.mail import mail
+from pretix.base.models import Event, Organizer, OutgoingMail, User
+from pretix.base.services.mail import mail, mail_send_task
 
 
 @pytest.fixture
@@ -162,6 +163,101 @@ def test_send_mail_with_user_locale(env):
     assert 'The language code used for rendering this email is de.' in djmail.outbox[0].body
 
 
+@pytest.mark.django_db
+def test_queue_state_sent(env):
+    m = OutgoingMail.objects.create(
+        to=['recipient@example.com'],
+        subject='Test',
+        body_plain='Test',
+        sender='sender@example.com',
+        headers={},
+    )
+    assert m.status == OutgoingMail.STATUS_QUEUED
+    mail_send_task.apply(kwargs={
+        'outgoing_mail': m.pk,
+    }, max_retries=0)
+    m.refresh_from_db()
+    assert m.status == OutgoingMail.STATUS_SENT
+
+
+@pytest.mark.django_db
+@override_settings(EMAIL_BACKEND='pretix.testutils.mail.PermanentlyFailingEmailBackend')
+def test_queue_state_permanent_failure(env):
+    m = OutgoingMail.objects.create(
+        to=['recipient@example.com'],
+        subject='Test',
+        body_plain='Test',
+        sender='sender@example.com',
+        headers={},
+    )
+    assert m.status == OutgoingMail.STATUS_QUEUED
+    mail_send_task.apply(kwargs={
+        'outgoing_mail': m.pk,
+    }, max_retries=0)
+    m.refresh_from_db()
+    assert m.status == OutgoingMail.STATUS_FAILED
+
+
+@pytest.mark.django_db
+@override_settings(EMAIL_BACKEND='pretix.testutils.mail.FailingEmailBackend')
+def test_queue_state_retry_failure(env, monkeypatch):
+    def retry(*args, **kwargs):
+        raise Exception()
+
+    monkeypatch.setattr('celery.app.task.Task.retry', retry, raising=True)
+    m = OutgoingMail.objects.create(
+        to=['recipient@example.com'],
+        subject='Test',
+        body_plain='Test',
+        sender='sender@example.com',
+        headers={},
+    )
+    assert m.status == OutgoingMail.STATUS_QUEUED
+    mail_send_task.apply(kwargs={
+        'outgoing_mail': m.pk,
+    }, max_retries=0)
+    m.refresh_from_db()
+    assert m.status == OutgoingMail.STATUS_AWAWITING_RETRY
+    assert m.retry_after > now()
+
+
+@pytest.mark.django_db
+def test_queue_state_foreign_key_handling():
+    o = Organizer.objects.create(name='Dummy', slug='dummy')
+    event = Event.objects.create(
+        organizer=o, name='Dummy', slug='dummy',
+        date_from=now()
+    )
+
+    mail_queued = OutgoingMail.objects.create(
+        organizer=o,
+        event=event,
+        to=['recipient@example.com'],
+        subject='Test',
+        body_plain='Test',
+        sender='sender@example.com',
+        headers={},
+    )
+    mail_sent = OutgoingMail.objects.create(
+        organizer=o,
+        event=event,
+        to=['recipient@example.com'],
+        subject='Test',
+        body_plain='Test',
+        sender='sender@example.com',
+        headers={},
+        status=OutgoingMail.STATUS_SENT,
+    )
+
+    event.delete()
+
+    assert not OutgoingMail.objects.filter(pk=mail_queued.pk).exists()
+    assert OutgoingMail.objects.get(pk=mail_sent.pk).event is None
+
+    o.delete()
+    assert not OutgoingMail.objects.filter(pk=mail_sent.pk).exists()
+
+
 @pytest.mark.django_db
 def test_sendmail_placeholder(env):
     djmail.outbox = []