From b2721db8e08163da2654231691f9938c5e338e72 Mon Sep 17 00:00:00 2001
From: Raphael Michel <mail@raphaelmichel.de>
Date: Fri, 13 Apr 2018 10:14:54 +0200
Subject: [PATCH] Refs #634 -- Re-allow deleting the last subevent and fix UI
 crashes

---
 src/pretix/base/models/event.py        |  2 +-
 src/pretix/control/views/dashboards.py | 13 ++++++++-----
 src/pretix/control/views/subevents.py  |  7 ++-----
 src/pretix/control/views/typeahead.py  | 15 +++++++++------
 4 files changed, 20 insertions(+), 17 deletions(-)

diff --git a/src/pretix/base/models/event.py b/src/pretix/base/models/event.py
index 8190139d98..eba442c1e2 100644
--- a/src/pretix/base/models/event.py
+++ b/src/pretix/base/models/event.py
@@ -660,7 +660,7 @@ class SubEvent(EventMixin, LoggedModel):
         return self.event.currency
 
     def allow_delete(self):
-        return self.event.subevents.count() > 1
+        return not self.orderposition_set.exists()
 
     def delete(self, *args, **kwargs):
         super().delete(*args, **kwargs)
diff --git a/src/pretix/control/views/dashboards.py b/src/pretix/control/views/dashboards.py
index e25eb81d48..398df7d2a5 100644
--- a/src/pretix/control/views/dashboards.py
+++ b/src/pretix/control/views/dashboards.py
@@ -14,7 +14,7 @@ from django.utils import formats
 from django.utils.formats import date_format
 from django.utils.html import escape
 from django.utils.timezone import now
-from django.utils.translation import ugettext_lazy as _, ungettext
+from django.utils.translation import ugettext_lazy as _, ungettext, pgettext
 
 from pretix.base.models import (
     Item, Order, OrderPosition, RequiredAction, SubEvent, Voucher,
@@ -329,10 +329,13 @@ def widgets_for_event_qs(request, qs, user, nmax):
     for event in events:
         tz = pytz.timezone(event.cache.get_or_set('timezone', lambda: event.settings.timezone))
         if event.has_subevents:
-            dr = daterange(
-                (event.min_from).astimezone(tz),
-                (event.max_fromto or event.max_to or event.max_from).astimezone(tz)
-            )
+            if event.min_from is None:
+                dr = pgettext("subevent", "No dates")
+            else:
+                dr = daterange(
+                    (event.min_from).astimezone(tz),
+                    (event.max_fromto or event.max_to or event.max_from).astimezone(tz)
+                )
         else:
             if event.date_to:
                 dr = daterange(event.date_from.astimezone(tz), event.date_to.astimezone(tz))
diff --git a/src/pretix/control/views/subevents.py b/src/pretix/control/views/subevents.py
index b4026e0446..bddda51969 100644
--- a/src/pretix/control/views/subevents.py
+++ b/src/pretix/control/views/subevents.py
@@ -98,7 +98,7 @@ class SubEventDelete(EventPermissionRequiredMixin, DeleteView):
             raise Http404(pgettext_lazy("subevent", "The requested date does not exist."))
 
     def get(self, request, *args, **kwargs):
-        if self.get_object().orderposition_set.count() > 0:
+        if not self.get_object().allow_delete():
             messages.error(request, pgettext_lazy('subevent', 'A date can not be deleted if orders already have been '
                                                               'placed.'))
             return HttpResponseRedirect(self.get_success_url())
@@ -109,13 +109,10 @@ class SubEventDelete(EventPermissionRequiredMixin, DeleteView):
         self.object = self.get_object()
         success_url = self.get_success_url()
 
-        if self.object.orderposition_set.count() > 0:
+        if not self.object.allow_delete():
             messages.error(request, pgettext_lazy('subevent', 'A date can not be deleted if orders already have been '
                                                               'placed.'))
             return HttpResponseRedirect(self.get_success_url())
-        elif not self.object.allow_delete():  # checking if this is the last date in the event series
-            messages.error(request, pgettext_lazy('subevent', 'The last date of an event series can not be deleted.'))
-            return HttpResponseRedirect(self.get_success_url())
         else:
             self.object.log_action('pretix.subevent.deleted', user=self.request.user)
             self.object.delete()
diff --git a/src/pretix/control/views/typeahead.py b/src/pretix/control/views/typeahead.py
index 0e98cfabbd..6bb6ab3b8e 100644
--- a/src/pretix/control/views/typeahead.py
+++ b/src/pretix/control/views/typeahead.py
@@ -8,7 +8,7 @@ from django.db.models.functions import Coalesce, Greatest
 from django.http import JsonResponse
 from django.urls import reverse
 from django.utils.timezone import make_aware
-from django.utils.translation import ugettext as _
+from django.utils.translation import ugettext as _, pgettext
 
 from pretix.base.models import Organizer, User
 from pretix.control.permissions import event_permission_required
@@ -38,11 +38,14 @@ def event_list(request):
 
         dr = e.get_date_range_display()
         if e.has_subevents:
-            tz = pytz.timezone(e.settings.timezone)
-            dr = _('Series:') + ' ' + daterange(
-                e.min_from.astimezone(tz),
-                (e.max_fromto or e.max_to or e.max_from).astimezone(tz)
-            )
+            if e.min_from is None:
+                dr = pgettext('subevent', 'No dates')
+            else:
+                tz = pytz.timezone(e.settings.timezone)
+                dr = _('Series:') + ' ' + daterange(
+                    e.min_from.astimezone(tz),
+                    (e.max_fromto or e.max_to or e.max_from).astimezone(tz)
+                )
         return {
             'id': e.pk,
             'slug': e.slug,