Fix handling of default ticket layouts during event cloning

src/pretix/api/serializers/event.py

@@ -411,7 +411,7 @@ class CloneEventSerializer(EventSerializer):
         has_subevents = validated_data.pop('has_subevents', None)
         tz = validated_data.pop('timezone', None)
         sales_channels = validated_data.pop('sales_channels', None)
-        new_event = super().create(validated_data)
+        new_event = super().create({**validated_data, 'plugins': None})
 
         event = Event.objects.filter(slug=self.context['event'], organizer=self.context['organizer'].pk).first()
         new_event.copy_data_from(event)

src/pretix/api/views/event.py

@@ -241,13 +241,17 @@ class EventViewSet(viewsets.ModelViewSet):
             except Event.DoesNotExist:
                 raise ValidationError('Event to copy from was not found')
 
+        # Ensure that .installed() is only called when we NOT clone
+        plugins = serializer.validated_data.pop('plugins', None)
+        serializer.validated_data['plugins'] = None
+
         new_event = serializer.save(organizer=self.request.organizer)
 
         if copy_from:
             new_event.copy_data_from(copy_from)
 
-            if 'plugins' in serializer.validated_data:
-                new_event.set_active_plugins(serializer.validated_data['plugins'])
+            if plugins:
+                new_event.set_active_plugins(plugins)
             if 'is_public' in serializer.validated_data:
                 new_event.is_public = serializer.validated_data['is_public']
             if 'testmode' in serializer.validated_data:
@@ -262,6 +266,10 @@ class EventViewSet(viewsets.ModelViewSet):
         else:
             serializer.instance.set_defaults()
 
+            if plugins:
+                new_event.set_active_plugins(plugins)
+                new_event.save(update_fields=['plugins'])
+
         serializer.instance.log_action(
             'pretix.event.added',
             user=self.request.user,