Fix #1178 -- Invalidate ticket cache after order locale change

src/pretix/api/views/order.py

@@ -514,6 +514,7 @@ class OrderViewSet(viewsets.ModelViewSet):
                 )
 
             serializer.save()
+            tickets.invalidate_cache.apply_async(kwargs={'event': serializer.instance.event.pk, 'order': serializer.instance.pk})
 
         if 'invoice_address' in self.request.data:
             order_modified.send(sender=serializer.instance.event, order=serializer.instance)

src/pretix/base/views/tasks.py

@@ -133,7 +133,7 @@ class AsyncAction:
             return str(exception)
         else:
             logger.error('Unexpected exception: %r' % exception)
-            return _('An unexpected error has occurred.')
+            return _('An unexpected error has occurred, please try again later.')
 
     def get_success_message(self, value):
         return _('The task has been completed.')

src/pretix/control/views/orders.py

@@ -1411,6 +1411,7 @@ class OrderLocaleChange(OrderView):
             )
 
             self.form.save()
+            tickets.invalidate_cache.apply_async(kwargs={'event': self.request.event.pk, 'order': self.order.pk})
             messages.success(self.request, _('The order has been changed.'))
             return redirect(self.get_order_url())
         return self.get(*args, **kwargs)