Fixed #7276 -- Delete multi-table objects correctly.

When model inheritance is used, the parent objects should be deleted as part of
the delete() call on the child.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@7784 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/base.py

@@ -395,6 +395,21 @@ class Model(object):
                 for sub_obj in getattr(self, rel_opts_name).all():
                     sub_obj._collect_sub_objects(seen_objs, self.__class__, related.field.null)
 
+        # Handle any ancestors (for the model-inheritance case). We do this by
+        # traversing to the most remote parent classes -- those with no parents
+        # themselves -- and then adding those instances to the collection. That
+        # will include all the child instances down to "self".
+        parent_stack = self._meta.parents.values()
+        while parent_stack:
+            link = parent_stack.pop()
+            parent_obj = getattr(self, link.name)
+            if parent_obj._meta.parents:
+                parent_stack.extend(parent_obj._meta.parents.values())
+                continue
+            # At this point, parent_obj is base class (no ancestor models). So
+            # delete it and all its descendents.
+            parent_obj._collect_sub_objects(seen_objs)
+
     def delete(self):
         assert self._get_pk_val() is not None, "%s object can't be deleted because its %s attribute is set to None." % (self._meta.object_name, self._meta.pk.attname)
 

tests/regressiontests/model_inheritance_regress/models.py

@@ -131,4 +131,26 @@ __test__ = {'API_TESTS':"""
 >>> Child.objects.dates('created', 'month')
 [datetime.datetime(2008, 6, 1, 0, 0)]
 
+# Regression test for #7276: calling delete() on a model with multi-table
+# inheritance should delete the associated rows from any ancestor tables, as
+# well as any descendent objects.
+
+>>> ident = ItalianRestaurant.objects.all()[0].id
+>>> Place.objects.get(pk=ident)
+<Place: Guido's All New House of Pasta the place>
+>>> xx = Restaurant.objects.create(name='a', address='xx', serves_hot_dogs=True, serves_pizza=False)
+
+# This should delete both Restuarants, plus the related places, plus the ItalianRestaurant.
+>>> Restaurant.objects.all().delete()
+
+>>> Place.objects.get(pk=ident)
+Traceback (most recent call last):
+...
+DoesNotExist: Place matching query does not exist.
+
+>>> ItalianRestaurant.objects.get(pk=ident)
+Traceback (most recent call last):
+...
+DoesNotExist: ItalianRestaurant matching query does not exist.
+
 """}