fix #6

actions/models.py

@@ -279,7 +279,7 @@ class Action(ModelWithImage, OrderedModel, ClusterableModel):
     """One action/measure tracked in an action plan."""
 
     plan = ParentalKey(
-        Plan, on_delete=models.CASCADE, default=latest_plan, related_name='actions',
+        Plan, on_delete=models.CASCADE, related_name='actions',
         verbose_name=_('plan')
     )
     name = models.CharField(max_length=1000, verbose_name=_('name'))
@@ -401,8 +401,8 @@ def clean(self):
 
     def save(self, *args, **kwargs):
         if self.pk is None:
-            qs = self.plan.objects.actions.all()
-            max_order = qs.aggregate(Max(self.order))['%s__max' % self.order] or 0
+            qs = self.plan.actions.values('order').order_by()
+            max_order = qs.aggregate(Max('order'))['order__max'] or 0
             self.order = max_order
         return super().save(*args, **kwargs)
 

actions/wagtail_admin.py

@@ -183,8 +183,18 @@ def get_form_class(self, request=None):
         return form_class
 
 
+class ActionCreateView(AplansCreateView):
+    def get_instance(self):
+        # Override default implementation, which would try to create an
+        # instance of self.model (i.e., Action) without a plan, causing an
+        # error
+        plan = self.request.user.get_active_admin_plan()
+        return getattr(self, 'instance', None) or Action(plan=plan)
+
+
 class ActionAdmin(OrderableMixin, AplansModelAdmin):
     model = Action
+    create_view_class = ActionCreateView
     menu_icon = 'fa-cubes'  # change as required
     menu_label = _('Actions')
     menu_order = 1