Message3083

Pickling of a class derived from dict creates an empty pickle in jython
2.2.1. In contrast Python 2.5.2 delivers the expected result.
I dont know how to solve the problem. 

# code:

from __future__ import generators

class MyDict(dict): 
    def __init__(self, d = None):
        if d == None: d = {}
        dict.__init__(d)

if __name__ == "__main__":
    import pickle    
           
    dd = MyDict()
    dd['z'] = [0,1]
    dd['b'] = [2,3]
    p = pickle.dumps(dd)
    print "-> pickle p:\n", p
    u = pickle.loads(p)
    print "-> MyDict dd:\n", dd
    print "-> reconstructed MyDict u:\n", u

# jython 2.2.1 output with empty pickle p:

-> pickle p:
c__main__
MyDict
p0
(tp1
Rp2
.
-> MyDict dd:
{'b': [2, 3], 'z': [0, 1]}
-> reconstructed MyDict u:
{}

# in contrast python 2.5.2 output with filled pickle p:

-> pickle p:
ccopy_reg
_reconstructor
p0
(c__main__
MyDict
p1
c__builtin__
dict
p2
(dp3
S'z'
p4
(lp5
I0
aI1
asS'b'
p6
(lp7
I2
aI3
astp8
Rp9
.
-> MyDict dd:
{'z': [0, 1], 'b': [2, 3]}
-> reconstructed MyDict u:
{'z': [0, 1], 'b': [2, 3]}