Fixed #17918 - Handle proxy models correctly when sorting deletions for databases without deferred constraints. Thanks Nate Bragg for the report.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17756 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 12 insertions, 3 deletions

diff --git a/django/db/models/deletion.py b/django/db/models/deletion.py
index 7d6594afc0..730847ef21 100644
--- a/django/db/models/deletion.py
+++ b/django/db/models/deletion.py
@@ -76,6 +76,12 @@ class Collector(object):
         self.data = {}
         self.batches = {} # {model: {field: set([instances])}}
         self.field_updates = {} # {model: {(field, value): set([instances])}}
+
+        # Tracks deletion-order dependency for databases without transactions
+        # or ability to defer constraint checks. Only concrete model classes
+        # should be included, as the dependencies exist only between actual
+        # database tables; proxy models are represented here by their concrete
+        # parent.
         self.dependencies = {} # {model: set([models])}
 
     def add(self, objs, source=None, nullable=False, reverse_dependency=False):
@@ -101,7 +107,8 @@ class Collector(object):
         if source is not None and not nullable:
             if reverse_dependency:
                 source, model = model, source
-            self.dependencies.setdefault(source, set()).add(model)
+            self.dependencies.setdefault(
+                source._meta.concrete_model, set()).add(model._meta.concrete_model)
         return new_objs
 
     def add_batch(self, model, field, objs):
@@ -197,15 +204,17 @@ class Collector(object):
 
     def sort(self):
         sorted_models = []
+        concrete_models = set()
         models = self.data.keys()
         while len(sorted_models) < len(models):
             found = False
             for model in models:
                 if model in sorted_models:
                     continue
-                dependencies = self.dependencies.get(model)
-                if not (dependencies and dependencies.difference(sorted_models)):
+                dependencies = self.dependencies.get(model._meta.concrete_model)
+                if not (dependencies and dependencies.difference(concrete_models)):
                     sorted_models.append(model)
+                    concrete_models.add(model._meta.concrete_model)
                     found = True
             if not found:
                 return