Merge "Handle unregistered nested objects"

oslo_versionedobjects/base.py

@@ -1147,7 +1147,11 @@ def obj_tree_get_versions(objname, tree=None):
         else:
             continue
 
-        obj_tree_get_versions(child_cls, tree=tree)
+        try:
+            obj_tree_get_versions(child_cls, tree=tree)
+        except IndexError:
+            raise exception.UnregisteredSubobject(
+                child_objname=child_cls, parent_objname=objname)
     return tree
 
 

oslo_versionedobjects/exception.py

@@ -186,3 +186,8 @@ class InvalidTargetVersion(VersionedObjectsException):
 
 class TargetBeforeSubobjectExistedException(VersionedObjectsException):
     msg_fmt = _("No subobject existed at version %(target_version)s")
+
+
+class UnregisteredSubobject(VersionedObjectsException):
+    msg_fmt = _("%(child_objname)s is referenced by %(parent_objname)s but "
+                "is not registered")

oslo_versionedobjects/tests/test_objects.py

@@ -2341,6 +2341,22 @@ class TestUtilityMethods(test.TestCase):
                           'TestChildTwo': '4.56'},
                          tree)
 
+    def test_missing_referenced(self):
+        """Ensure a missing child object is highlighted."""
+        @base.VersionedObjectRegistry.register
+        class TestObjectFoo(base.VersionedObject):
+            VERSION = '1.23'
+            fields = {
+                # note that this object does not exist
+                'child': fields.ObjectField('TestChildBar'),
+            }
+
+        exc = self.assertRaises(exception.UnregisteredSubobject,
+                                base.obj_tree_get_versions,
+                                'TestObjectFoo')
+        self.assertIn('TestChildBar is referenced by TestObjectFoo',
+                      exc.format_message())
+
 
 class TestListObjectConcat(test.TestCase):
     def test_list_object_concat(self):