Ticket #11576: filterspecs.py.2.patch

django/contrib/admin/filterspecs.py

@@ -120 +120 @@
                              '%s__month' % f.name: str(today.month)}),
             (_('This year'), {'%s__year' % self.field.name: str(today.year)})
         )
+        if self.field.null:
+            self.links += ((_('None'), {'%s__isnull' % self.field.name: 'True'}),)
 
     def title(self):
         return self.field.verbose_name