Fix bug that prevents users from deleting sponsorship applications (#1978)

* Just remove delete from actions instead of disabling delete permission

* Polymorphic models should use non polymorphic model to enable cascading deletion

* Explicit is always better than implicit =)

Author: berinhard

sponsors/admin.py

@@ -831,8 +831,11 @@ def get_queryset(self, *args, **kwargs):
         classes = self.get_child_models(*args, **kwargs)
         return self.model.objects.select_related("content_type").instance_of(*classes)
 
-    def has_delete_permission(self, *args, **kwargs):
-        return False
+    def get_actions(self, request):
+        actions = super().get_actions(request)
+        if 'delete_selected' in actions:
+            del actions['delete_selected']
+        return actions
 
     def has_add_permission(self, *args, **kwargs):
         return False

sponsors/models/assets.py

@@ -10,6 +10,7 @@
 from django.contrib.contenttypes.fields import GenericForeignKey
 from django.contrib.contenttypes.models import ContentType
 from django.db.models.fields.files import ImageFieldFile, FileField
+from polymorphic.managers import PolymorphicManager
 from polymorphic.models import PolymorphicModel
 
 
@@ -27,6 +28,8 @@ class GenericAsset(PolymorphicModel):
     """
     Base class used to add required assets to Sponsor or Sponsorship objects
     """
+    objects = PolymorphicManager()
+    non_polymorphic = models.Manager()
 
     # UUID can't be the object ID because Polymorphic expects default django integer ID
     uuid = models.UUIDField(default=uuid.uuid4, editable=False)
@@ -47,6 +50,7 @@ class Meta:
         verbose_name = "Asset"
         verbose_name_plural = "Assets"
         unique_together = ["content_type", "object_id", "internal_name"]
+        base_manager_name = 'non_polymorphic'
 
     @property
     def value(self):

sponsors/models/benefits.py

@@ -490,12 +490,14 @@ class BenefitFeature(PolymorphicModel):
     Base class for sponsor benefits features.
     """
     objects = BenefitFeatureQuerySet.as_manager()
+    non_polymorphic = models.Manager()
 
     sponsor_benefit = models.ForeignKey("sponsors.SponsorBenefit", on_delete=models.CASCADE)
 
     class Meta:
         verbose_name = "Benefit Feature"
         verbose_name_plural = "Benefit Features"
+        base_manager_name = 'non_polymorphic'
 
     def display_modifier(self, name, **kwargs):
         return name