Wrong ObjectIdField to_mongo() and validate() methods behavior on Python 3

[lig]

ObjectIdField uses unicode(value) to prepare value. 2to3 converts it into str(value) that will lead to "b'…'" strings for values of type bytes on Python 3.

It is better to use decode() method on bytes instances on Python 3. Not sure how to achieve this via 2to3.

[lig]

Something like

if isinstance(basestring, value) and hasattr(value, 'decode'):
    value = value.decode()

after if not isinstance(value, ObjectId): in ObjectIdField.to_mongo should help.

[bagerard]

I believe this got fixed and could be closed. The current code in ObjectIdField uses the six library