Dictionary becomes basic in MongoEngine after assignment

Question

I am using mongoengine 0.9.0

class EntityChange(Document): ... old_data = DictField() new_data = DictField() 

I want to save dict objects in old_data and new_data .

Why do fields become BaseList after assignment?

 data = {u'int_id': 100500, u'_cls': 'BuildingKind', ...} instance = EntityChange() instance.new_data = data # after that # isinstance(instance, BaseList) is True # isinstance(instance, BaseDict) is False # instance.new_data == ['int_id', 'id', ...] is True. why? 

Answer 1

Passing a dict containing _cls or _types caused an error in mongoengine .

The fix was fixed and was merged in versions 0.10.1 and later.