Cancelling events: Allow to inform waiting list

src/pretix/base/services/cancelevent.py

@@ -12,9 +12,10 @@ from pretix.base.email import get_email_context
 from pretix.base.i18n import language
 from pretix.base.models import (
     Event, InvoiceAddress, Order, OrderFee, OrderPosition, SubEvent, User,
+    WaitingListEntry,
 )
 from pretix.base.services.locking import LockTimeoutException
-from pretix.base.services.mail import SendMailException, TolerantDict
+from pretix.base.services.mail import SendMailException, TolerantDict, mail
 from pretix.base.services.orders import (
     OrderChangeManager, OrderError, _cancel_order, _try_auto_refund,
 )
@@ -24,6 +25,22 @@ from pretix.celery_app import app
 logger = logging.getLogger(__name__)
 
 
+def _send_wle_mail(wle: WaitingListEntry, subject: LazyI18nString, message: LazyI18nString, subevent: SubEvent):
+    with language(wle.locale):
+        email_context = get_email_context(event_or_subevent=subevent or wle.event, event=wle.event)
+        try:
+            mail(
+                wle.email,
+                str(subject).format_map(TolerantDict(email_context)),
+                message,
+                email_context,
+                wle.event,
+                locale=wle.locale
+            )
+        except SendMailException:
+            logger.exception('Waiting list canceled email could not be sent')
+
+
 def _send_mail(order: Order, subject: LazyI18nString, message: LazyI18nString, subevent: SubEvent,
                refund_amount: Decimal, user: User, positions: list):
     with language(order.locale):
@@ -68,10 +85,14 @@ def _send_mail(order: Order, subject: LazyI18nString, message: LazyI18nString, s
 
 @app.task(base=ProfiledEventTask, bind=True, max_retries=5, default_retry_delay=1, throws=(OrderError,))
 def cancel_event(self, event: Event, subevent: int, auto_refund: bool, keep_fee_fixed: str,
-                 keep_fee_percentage: str, keep_fees: bool, send: bool, send_subject: dict,
-                 send_message: dict, user: int):
+                 keep_fee_percentage: str, keep_fees: bool,
+                 send: bool, send_subject: dict, send_message: dict,
+                 send_waitinglist: bool=False, send_waitinglist_subject: dict={}, send_waitinglist_message: dict={},
+                 user: int=None):
     send_subject = LazyI18nString(send_subject)
     send_message = LazyI18nString(send_message)
+    send_waitinglist_subject = LazyI18nString(send_waitinglist_subject)
+    send_waitinglist_message = LazyI18nString(send_waitinglist_message)
     if user:
         user = User.objects.get(pk=user)
 
@@ -115,7 +136,7 @@ def cancel_event(self, event: Event, subevent: int, auto_refund: bool, keep_fee_
         )
     else:
         orders_to_change = event.orders.none()
-        subevent.log_action(
+        event.log_action(
             'pretix.event.canceled', user=user,
         )
 
@@ -195,4 +216,7 @@ def cancel_event(self, event: Event, subevent: int, auto_refund: bool, keep_fee_
             if send:
                 _send_mail(o, send_subject, send_message, subevent, refund_amount, user, positions)
 
+    for wle in event.waitinglistentries.filter(subevent=subevent, voucher__isnull=True):
+        _send_wle_mail(wle, send_waitinglist_subject, send_waitinglist_message, subevent)
+
     return failed

src/pretix/control/forms/orders.py

@@ -552,6 +552,12 @@ class EventCancelForm(forms.Form):
     )
     send_subject = forms.CharField()
     send_message = forms.CharField()
+    send_waitinglist = forms.BooleanField(
+        label=_("Send information to waiting list"),
+        required=False
+    )
+    send_waitinglist_subject = forms.CharField()
+    send_waitinglist_message = forms.CharField()
 
     def _set_field_placeholders(self, fn, base_parameters):
         phs = [
@@ -596,6 +602,28 @@ class EventCancelForm(forms.Form):
                                                       'order', 'event'])
         self._set_field_placeholders('send_message', ['event_or_subevent', 'refund_amount', 'position_or_address',
                                                       'order', 'event'])
+        self.fields['send_waitinglist_subject'] = I18nFormField(
+            label=_("Subject"),
+            required=True,
+            initial=_('Canceled: {event}'),
+            widget=I18nTextInput,
+            locales=self.event.settings.get('locales'),
+        )
+        self.fields['send_waitinglist_message'] = I18nFormField(
+            label=_('Message'),
+            widget=I18nTextarea,
+            required=True,
+            locales=self.event.settings.get('locales'),
+            initial=LazyI18nString.from_gettext(gettext_noop(
+                'Hello,\n\n'
+                'with this email, we regret to inform you that {event} has been canceled.\n\n'
+                'You will therefore not receive a ticket from the waiting list.\n\n'
+                'Best regards,\n\n'
+                'Your {event} team'
+            ))
+        )
+        self._set_field_placeholders('send_waitinglist_subject', ['event_or_subevent', 'event'])
+        self._set_field_placeholders('send_waitinglist_message', ['event_or_subevent', 'event'])
 
         if self.event.has_subevents:
             self.fields['subevent'].queryset = self.event.subevents.all()

src/pretix/control/templates/pretixcontrol/orders/cancel.html

@@ -43,6 +43,26 @@
             {% bootstrap_field form.send_subject layout="horizontal" %}
             {% bootstrap_field form.send_message layout="horizontal" %}
         </fieldset>
+        <fieldset>
+            <legend>{% trans "Waiting list" %}</legend>
+            <p>
+                {% blocktrans trimmed %}
+                    Your waiting list will not be deleted automatically, but it will receive no new tickets due to the
+                    products being disabled. You can choose to inform people on the waiting list by using this option.
+                {% endblocktrans %}
+            </p>
+            <p>
+                <strong>
+                    {% blocktrans trimmed %}
+                        You should not execute this function multiple times for the same event, or everyone on the
+                        waiting list will get multiple emails.
+                    {% endblocktrans %}
+                </strong>
+            </p>
+            {% bootstrap_field form.send_waitinglist layout="control" %}
+            {% bootstrap_field form.send_waitinglist_subject layout="horizontal" %}
+            {% bootstrap_field form.send_waitinglist_message layout="horizontal" %}
+        </fieldset>
         <div class="form-group submit-group">
             <button type="submit" class="btn btn-danger btn-save">
                 {% trans "Cancel all orders" %}

src/pretix/control/views/orders.py

@@ -1915,6 +1915,9 @@ class EventCancel(EventPermissionRequiredMixin, AsyncAction, FormView):
             send=form.cleaned_data.get('send'),
             send_subject=form.cleaned_data.get('send_subject').data,
             send_message=form.cleaned_data.get('send_message').data,
+            send_waitinglist=form.cleaned_data.get('send'),
+            send_waitinglist_subject=form.cleaned_data.get('send_waitinglist_subject').data,
+            send_waitinglist_message=form.cleaned_data.get('send_waitinglist_message').data,
             user=self.request.user.pk,
         )