From 4867c2d18d5faf29747fd989bce0b445a3b0ff71 Mon Sep 17 00:00:00 2001
From: Sam Betts <sam@code-smash.net>
Date: Wed, 20 Jan 2016 10:40:11 +0000
Subject: [PATCH] Make sure functions in child object registries work

This patch ensures that the VersionedObjectRegistry.__new__ function
always returns the correct class thats being created so that overridden
functions are applied correctly, when using a subclassed object
registry. Without this patch when using multiple child object registries
only the first child's overridden functions work correctly.

Change-Id: I11fef67b5bd16377086027d72f8e417c2221b5b4
Closes-Bug: #1536113
---
 oslo_versionedobjects/base.py               |  8 ++--
 oslo_versionedobjects/tests/test_objects.py | 41 +++++++++++++++------
 2 files changed, 35 insertions(+), 14 deletions(-)

diff --git a/oslo_versionedobjects/base.py b/oslo_versionedobjects/base.py
index 8aa5dc4..71fc92f 100644
--- a/oslo_versionedobjects/base.py
+++ b/oslo_versionedobjects/base.py
@@ -101,11 +101,13 @@ class VersionedObjectRegistry(object):
 
     def __new__(cls, *args, **kwargs):
         if not VersionedObjectRegistry._registry:
-            VersionedObjectRegistry._registry = \
-                object.__new__(cls, *args, **kwargs)
+            VersionedObjectRegistry._registry = object.__new__(
+                VersionedObjectRegistry, *args, **kwargs)
             VersionedObjectRegistry._registry._obj_classes = \
                 collections.defaultdict(list)
-        return VersionedObjectRegistry._registry
+        self = object.__new__(cls, *args, **kwargs)
+        self._obj_classes = VersionedObjectRegistry._registry._obj_classes
+        return self
 
     def registration_hook(self, cls, index):
         pass
diff --git a/oslo_versionedobjects/tests/test_objects.py b/oslo_versionedobjects/tests/test_objects.py
index 705780d..94202bb 100755
--- a/oslo_versionedobjects/tests/test_objects.py
+++ b/oslo_versionedobjects/tests/test_objects.py
@@ -289,21 +289,40 @@ class TestRegistry(test.TestCase):
             mock_hook.assert_called_once_with(TestObjectNewer, 0)
 
     def test_subclassability(self):
-        class MyRegistry(base.VersionedObjectRegistry):
-            pass
+        class MyRegistryOne(base.VersionedObjectRegistry):
 
-        @MyRegistry.register
-        class ObjectInSubclassedRegistry(object):
-            fields = {}
+            def registration_hook(self, cls, index):
+                cls.reg_to = "one"
 
-            @classmethod
-            def obj_name(cls):
-                return cls.__name__
+        class MyRegistryTwo(base.VersionedObjectRegistry):
 
-        self.assertIn('ObjectInSubclassedRegistry',
-                      MyRegistry.obj_classes())
-        self.assertIn('ObjectInSubclassedRegistry',
+            def registration_hook(self, cls, index):
+                cls.reg_to = "two"
+
+        @MyRegistryOne.register
+        class AVersionedObject1(base.VersionedObject):
+            VERSION = '1.0'
+            fields = {'baz': fields.Field(fields.Integer())}
+
+        @MyRegistryTwo.register
+        class AVersionedObject2(base.VersionedObject):
+            VERSION = '1.0'
+            fields = {'baz': fields.Field(fields.Integer())}
+
+        self.assertIn('AVersionedObject1',
+                      MyRegistryOne.obj_classes())
+        self.assertIn('AVersionedObject2',
+                      MyRegistryOne.obj_classes())
+        self.assertIn('AVersionedObject1',
+                      MyRegistryTwo.obj_classes())
+        self.assertIn('AVersionedObject2',
+                      MyRegistryTwo.obj_classes())
+        self.assertIn('AVersionedObject1',
                       base.VersionedObjectRegistry.obj_classes())
+        self.assertIn('AVersionedObject2',
+                      base.VersionedObjectRegistry.obj_classes())
+        self.assertEqual(AVersionedObject1.reg_to, "one")
+        self.assertEqual(AVersionedObject2.reg_to, "two")
 
 
 class TestObjMakeList(test.TestCase):