Use pickle to unknown objects about mongodict

[turicas]

I'm considering in do not implementing this issue. I think it should be in a level on top of mongodict (let the developer do this work outside mongodict). Summarizing possible problems:

• If mongodict tries automatically to pickle the object, it can lead to errors like outdated objects saved in the database (see the example below).
• We'd need a kind of "protocol" to discover which objects are pickled and which are not. It can be a mess (imagine the collection with lots of non-homogeneous data, but with the same schema).

The problems involving pickled objects are exemplified below:

from mongodict import MongoDict


class MyClass(object):
    pass

obj = MyClass()
obj.test = 123
my_dict = MongoDict()
my_dict['obj'] = obj
obj.python = 'rules'
assert my_dict['obj'] == obj # False

(I think) ZODB solves this problem forcing the developer to subclass a specific Persistent class, so it'll update object info in the database when you update the object automatically but as mongodict is not a object-oriented database, we can't force the developer to do it (maybe a library on top of mongodict can do it).

It's open for discussion.

[turicas]

Implemented on 194333f.