Hello everyone,
I have a problem with inheritance from list. I want to create a tree
like object where child nodes are kept in self[:] and every child has a
field that points to its parent. Pickling such an object, however,
throws an AssertionError. See below for source code and output of an
easy example case of my problem.
What did I do wrong?
Best regards,
Klaus
======== source:
class myList(list):
pass
class myObject:
def __init__(self, parent=None):
self.parent = parent
if __name__ == '__main__':
r = myList()
r.append( myObject(r) )
from pickle import dump, load
dump(r, file('/tmp/x', 'w'))
========= output:
Traceback (most recent call last):
File "<stdin>", line 1, in ?
File "/tmp/python-11053-o.py", line 15, in ?
dump(r, f)
File "/usr/lib/python2.4/pickle.py", line 1382, in dump
Pickler(file, protocol, bin).dump(obj)
File "/usr/lib/python2.4/pickle.py", line 231, in dump
self.save(obj)
File "/usr/lib/python2.4/pickle.py", line 338, in save
self.save_reduce(obj=obj, *rv)
File "/usr/lib/python2.4/pickle.py", line 419, in save_reduce
self.memoize(obj)
File "/usr/lib/python2.4/pickle.py", line 251, in memoize
assert id(obj) not in self.memo
AssertionError
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