dictsort with null values not working with Django 1.11

[Jean-Baptiste Pressac]

Hello,

I am trying to migrate from Python 2, Django 1.8 to Python 3, Django 1.11 and I have a little problem with dictsort filter whith Null values.

The following code was working on Django 1.8, Python 2 :

Extract from models.py:

class Edition(models.Model):

    titre = models.CharField(max_length=510, blank=True)

    annee_publication = models.IntegerField(blank=True, null=True)

    collectifs = models.ManyToManyField('Collectif', through='EditeOeuvre',

                                        related_name='edition_collectifs',

                                        verbose_name="Collectifs")

    [...]

class EditeOeuvre(models.Model):

    edition = models.ForeignKey('Edition')

    collectif = models.ForeignKey('Collectif', blank=True, null=True,)

    [...]

Extract from views.py:

def collectif(request, id):
    collectif = get_object_or_404(Collectif.objects.prefetch_related('edition_collectifs'), pk=id)
    [...]
    return render(request, 'prelib/collectif.html', context)

With Django 1.8, I could sort collectif.edition_collectifs.all even if some annee_publication were Null :

{% for edition in collectif.edition_collectifs.all|dictsort:"annee_publication" %}
{{ edition }}
{% endfor %}

With Django 1.11, if some annee_publication are Null, no {{ edition }} are displayed...

Is this a bug or did I something wrong ?

Thanks,