Implement filters with double-underscore clauses about django-modelcluster HOT 3 CLOSED

I just ran into this as well, it was the comments that did it for me (I have a pages & blog mix deployed right now).
If anybody is curious I used the "is_private" attribute on the request to make it usable for now.

if hasattr(request, 'is_preview') and request.is_preview:
    alternate-expression
else:
    double-underscore-expression

from django-modelcluster.

Implemented in #102 for expressions such as __lt. Following relations (e.g. page.photos.filter(author__name='Matthew')) and chaining (e.g. publish_date__year__gt=2017 are still outstanding, so leaving this issue open to cover those.

from django-modelcluster.

I think this is probably related to this issue...

We've run into AttributeErrors with ordering on fields in related models (being thrown here in utils.sort_by_fields: https://github.com/wagtail/django-modelcluster/blob/master/modelcluster/utils.py#L19)

Example code that produces this:

class ItemValue(models.Model):
    item = models.ForeignKey(...)

    class Meta:
        ordering = ("item__title")

The error thrown is AttributeError: 'ItemValue' object has no attribute 'item__title'.

This is happening when the ItemValue is being saved from an inline formset on a parent model.

from django-modelcluster.