Raise exception when synthetic field invalid

A check is introduced in the ``__init__`` method of ``NeutronObject``
class. This check ensures synthetic fields are valid in any oslo
versioned object.

Reference: I3c565f83098a03d210616f51d359ca45388aaf60

Depends-On: I12c7a330555966d30e44418cbd500958fe844462

Co-Authored-By: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>
Closes-Bug: #1614478

Change-Id: I33c41fbd4dd40ba292ebe67ac497372d4354f260

neutron/objects/base.py

@@ -290,6 +290,11 @@ class DeclarativeObject(abc.ABCMeta):
         if 'project_id' in cls.fields and 'tenant_id' not in cls.fields:
             cls.extra_filter_names.add('tenant_id')
 
+        invalid_fields = [f for f in cls.synthetic_fields
+                          if f not in cls.fields]
+        if invalid_fields:
+            raise o_exc.NeutronObjectValidatorException(fields=invalid_fields)
+
 
 @six.add_metaclass(DeclarativeObject)
 class NeutronDbObject(NeutronObject):

neutron/tests/unit/objects/test_base.py

@@ -1991,3 +1991,24 @@ class OperationOnStringAndJsonTestCase(test_base.BaseTestCase):
                 res = base.NeutronDbObject.filter_to_json_str(field_val,
                                                               default_val)
                 self.assertEqual(default_val, res)
+
+
+class NeutronObjectValidatorTestCase(test_base.BaseTestCase):
+
+    def test_load_wrong_synthetic_fields(self):
+        try:
+            @obj_base.VersionedObjectRegistry.register_if(False)
+            class FakeNeutronObjectSyntheticFieldWrong(base.NeutronDbObject):
+                # Version 1.0: Initial version
+                VERSION = '1.0'
+
+                db_model = FakeModel
+
+                fields = {
+                    'id': common_types.UUIDField(),
+                    'obj_field': common_types.UUIDField()
+                }
+
+                synthetic_fields = ['obj_field', 'wrong_synthetic_field_name']
+        except o_exc.NeutronObjectValidatorException as exc:
+            self.assertIn('wrong_synthetic_field_name', str(exc))