Fixed github issue 15 (query result incomplete with inheritance). Thanks to John Debs.

polymorphic/base.py

@@ -76,6 +76,13 @@ class PolymorphicModelBase(ModelBase):
         # for __init__ function of this class (monkeypatching inheritance accessors)
         new_class.polymorphic_super_sub_accessors_replaced = False
 
+        # determine the name of the primary key field and store it into the class variable
+        # polymorphic_primary_key_name (it is needed by query.py)
+        for f in new_class._meta.fields:
+            if f.primary_key and type(f)!=models.OneToOneField:
+                new_class.polymorphic_primary_key_name=f.name
+                break
+
         return new_class
 
     def get_inherited_managers(self, attrs):

polymorphic/query.py

@@ -161,7 +161,9 @@ class PolymorphicQuerySet(QuerySet):
         # We get different type(o.pk) in this case.
         # We work around this by using the real name of the field directly
         # for accessing the primary key of the the derived objects.
-        pk_name = self.model._meta.pk.name
+        # We might assume that self.model._meta.pk.name gives us the name of the primary key field,
+        # but it doesn't. Therefore we use polymorphic_primary_key_name, which we set up in base.py.
+        pk_name = self.model.polymorphic_primary_key_name
 
         # For each model in "idlist_per_model" request its objects (the real model)
         # from the db and store them in results[].
@@ -184,7 +186,7 @@ class PolymorphicQuerySet(QuerySet):
                     for select_field_name in self.query.extra_select.keys():
                         attr = getattr(base_result_objects_by_id[o_pk], select_field_name)
                         setattr(o, select_field_name, attr)
-                    
+
                 results[o_pk] = o
 
         # re-create correct order and return result list

polymorphic/tests.py

@@ -156,6 +156,14 @@ class InitTestModelSubclass(InitTestModel):
     def x(self):
         return 'XYZ'
 
+# models from github issue
+class Top(PolymorphicModel):
+    name = models.CharField(max_length=50)
+class Middle(Top):
+    description = models.TextField()
+class Bottom(Middle):
+    author = models.CharField(max_length=50)
+
 
 # UUID tests won't work with Django 1.1
 if not (django_VERSION[0] <= 1 and django_VERSION[1] <= 1):
@@ -610,6 +618,20 @@ __test__ = {"doctest": """
 #>>> print 'DiamondXY fields 1: field_b "%s", field_x "%s", field_y "%s"' % (o.field_b, o.field_x, o.field_y)
 #DiamondXY fields 1: field_b "a", field_x "x", field_y "y"
 
+# test for github issue
+>>> t = Top()
+>>> t.save()
+>>> m = Middle()
+>>> m.save()
+>>> b = Bottom()
+>>> b.save()
+>>> Top.objects.all()
+[<Top: Top object>, <Middle: Middle object>, <Bottom: Bottom object>]
+>>> Middle.objects.all()
+[<Middle: Middle object>, <Bottom: Bottom object>]
+>>> Bottom.objects.all()
+[<Bottom: Bottom object>]
+
 
 >>> settings.DEBUG=False