Fix bug with child/grandchild select_subclasses in Django 1.6+; thanks Keryn Knight.

CHANGES.rst

@@ -4,6 +4,10 @@ CHANGES
 master (unreleased)
 -------------------
 
+* Fix bug in `InheritanceManager` with grandchild classes on Django 1.6+;
+  `select_subclasses('child', 'child__grandchild')` would only ever get to the
+  child class. Thanks Keryn Knight for report and proposed fix.
+
 
 1.5.0 (2013.08.29)
 ------------------

model_utils/managers.py

@@ -46,9 +46,12 @@ class InheritanceQuerySet(QuerySet):
     def iterator(self):
         iter = super(InheritanceQuerySet, self).iterator()
         if getattr(self, 'subclasses', False):
+            # sort the subclass names longest first,
+            # so with 'a' and 'a__b' it goes as deep as possible
+            subclasses = sorted(self.subclasses, key=len, reverse=True)
             for obj in iter:
                 sub_obj = None
-                for s in self.subclasses:
+                for s in subclasses:
                     sub_obj = self._get_sub_obj_recurse(obj, s)
                     if sub_obj:
                         break

model_utils/tests/models.py

@@ -1,4 +1,7 @@
+from __future__ import unicode_literals
+
 from django.db import models
+from django.utils.encoding import python_2_unicode_compatible
 from django.utils.translation import ugettext_lazy as _
 
 from model_utils.models import TimeStampedModel, StatusModel, TimeFramedModel
@@ -15,6 +18,7 @@ class InheritanceManagerTestRelated(models.Model):
 
 
 
+@python_2_unicode_compatible
 class InheritanceManagerTestParent(models.Model):
     # FileField is just a handy descriptor-using field. Refs #6.
     non_related_field_using_descriptor = models.FileField(upload_to="test")
@@ -24,11 +28,17 @@ class InheritanceManagerTestParent(models.Model):
     objects = InheritanceManager()
 
 
+    def __str__(self):
+        return "%s(%s)" % (
+            self.__class__.__name__[len('InheritanceManagerTest'):],
+            self.pk,
+            )
+
+
 
 class InheritanceManagerTestChild1(InheritanceManagerTestParent):
     non_related_field_using_descriptor_2 = models.FileField(upload_to="test")
     normal_field_2 = models.TextField()
-    pass
 
 
 class InheritanceManagerTestGrandChild1(InheritanceManagerTestChild1):

model_utils/tests/tests.py

@@ -542,8 +542,26 @@ class InheritanceManagerTests(TestCase):
         self.assertEqual(
             set(
                 self.get_manager().select_subclasses(
-                    "inheritancemanagertestchild1__"
-                    "inheritancemanagertestgrandchild1"
+                    "inheritancemanagertestchild1__inheritancemanagertestgrandchild1"
+                    )
+                ),
+            children,
+            )
+
+
+    @skipUnless(django.VERSION >= (1, 6, 0), "test only applies to Django 1.6+")
+    def test_children_and_grandchildren(self):
+        children = set([
+                self.child1,
+                InheritanceManagerTestParent(pk=self.child2.pk),
+                self.grandchild1,
+                InheritanceManagerTestChild1(pk=self.grandchild1_2.pk),
+                ])
+        self.assertEqual(
+            set(
+                self.get_manager().select_subclasses(
+                    "inheritancemanagertestchild1",
+                    "inheritancemanagertestchild1__inheritancemanagertestgrandchild1"
                     )
                 ),
             children,