Don't follow references in _get_changed_fields (#422, #417)

A better fix so we dont follow down a references rabbit hole.

docs/changelog.rst

@@ -4,7 +4,7 @@ Changelog
 
 Changes in 0.8.4
 ================
-- Fixed _delta including referenced fields when dbref=False (#417)
+- Don't follow references in _get_changed_fields (#422, #417)
 - Allow args and kwargs to be passed through to_json (#420)
 
 Changes in 0.8.3

mongoengine/base/document.py

@@ -395,6 +395,7 @@ class BaseDocument(object):
         """
         EmbeddedDocument = _import_class("EmbeddedDocument")
         DynamicEmbeddedDocument = _import_class("DynamicEmbeddedDocument")
+        ReferenceField = _import_class("ReferenceField")
         _changed_fields = []
         _changed_fields += getattr(self, '_changed_fields', [])
 
@@ -405,31 +406,36 @@ class BaseDocument(object):
             inspected.add(self.id)
 
         for field_name in self._fields_ordered:
-
             db_field_name = self._db_field_map.get(field_name, field_name)
             key = '%s.' % db_field_name
-            field = self._data.get(field_name, None)
+            data = self._data.get(field_name, None)
-            if hasattr(field, 'id'):
+            field = self._fields.get(field_name)
-                if field.id in inspected:
-                    continue
-                inspected.add(field.id)
 
-            if (isinstance(field, (EmbeddedDocument, DynamicEmbeddedDocument))
+            if hasattr(data, 'id'):
+                if data.id in inspected:
+                    continue
+                inspected.add(data.id)
+            if isinstance(field, ReferenceField):
+                continue
+            elif (isinstance(data, (EmbeddedDocument, DynamicEmbeddedDocument))
                and db_field_name not in _changed_fields):
                  # Find all embedded fields that have been changed
-                changed = field._get_changed_fields(inspected)
+                changed = data._get_changed_fields(inspected)
                 _changed_fields += ["%s%s" % (key, k) for k in changed if k]
-            elif (isinstance(field, (list, tuple, dict)) and
+            elif (isinstance(data, (list, tuple, dict)) and
                     db_field_name not in _changed_fields):
                 # Loop list / dict fields as they contain documents
                 # Determine the iterator to use
-                if not hasattr(field, 'items'):
+                if not hasattr(data, 'items'):
-                    iterator = enumerate(field)
+                    iterator = enumerate(data)
                 else:
-                    iterator = field.iteritems()
+                    iterator = data.iteritems()
                 for index, value in iterator:
                     if not hasattr(value, '_get_changed_fields'):
                         continue
+                    if (hasattr(field, 'field') and
+                        isinstance(field.field, ReferenceField)):
+                        continue
                     list_key = "%s%s." % (key, index)
                     changed = value._get_changed_fields(inspected)
                     _changed_fields += ["%s%s" % (list_key, k)

tests/document/delta.py

@@ -328,14 +328,9 @@ class DeltaTest(unittest.TestCase):
         Person.drop_collection()
         Organization.drop_collection()
 
-        person = Person(name="owner")
+        person = Person(name="owner").save()
-        person.save()
+        employee = Person(name="employee").save()
-
+        organization = Organization(name="company").save()
-        employee = Person(name="employee")
-        employee.save()
-
-        organization = Organization(name="company")
-        organization.save()
 
         person.owns.append(organization)
         organization.owner = person
@@ -692,25 +687,32 @@ class DeltaTest(unittest.TestCase):
         person, organization, employee = self.circular_reference_deltas_2(Document, Document, True)
         employee.name = 'test'
 
-        self.assertEqual(organization._get_changed_fields(), ['employees.0.name'])
+        self.assertEqual(organization._get_changed_fields(), [])
 
         updates, removals = organization._delta()
         self.assertEqual({}, removals)
-        self.assertTrue('employees.0' in updates)
+        self.assertEqual({}, updates)
 
-        organization.save()
+        organization.employees.append(person)
+        updates, removals = organization._delta()
+        self.assertEqual({}, removals)
+        self.assertTrue('employees' in updates)
 
     def test_delta_with_dbref_false(self):
         person, organization, employee = self.circular_reference_deltas_2(Document, Document, False)
         employee.name = 'test'
 
-        self.assertEqual(organization._get_changed_fields(), ['employees.0.name'])
+        self.assertEqual(organization._get_changed_fields(), [])
 
         updates, removals = organization._delta()
         self.assertEqual({}, removals)
-        self.assertTrue('employees.0' in updates)
+        self.assertEqual({}, updates)
+
+        organization.employees.append(person)
+        updates, removals = organization._delta()
+        self.assertEqual({}, removals)
+        self.assertTrue('employees' in updates)
 
-        organization.save()
 
 if __name__ == '__main__':
     unittest.main()