roundtrip error of defaultdict with object and with nested

[sangjin-park]

from collections import defaultdict

import traceback

import jsonpickle

class Thing:
  pass

thing = Thing()
defdict = defaultdict(lambda: 0)
obj = [defdict, thing, thing]
try:
  encoded = jsonpickle.encode(obj, keys=True)
  decoded = jsonpickle.decode(encoded, keys=True)
except:
  traceback.print_exc()

print()

default_factory = lambda: 0
defdict = defaultdict(default_factory, {'a': defaultdict(default_factory)})
try:
  encoded = jsonpickle.encode(defdict, keys=True)
  decoded = jsonpickle.decode(encoded, keys=True)
except:
  traceback.print_exc()

produces

Traceback (most recent call last):
  File "/Users/kaien/git/jsonpickle/tests/defaultdict_check.py", line 15, in <module>
    decoded = jsonpickle.decode(encoded, keys=True)
  File "/Users/kaien/git/jsonpickle/jsonpickle/unpickler.py", line 41, in decode
    return context.restore(data, reset=reset, classes=classes)
  File "/Users/kaien/git/jsonpickle/jsonpickle/unpickler.py", line 152, in restore
    self._swap_proxies()
  File "/Users/kaien/git/jsonpickle/jsonpickle/unpickler.py", line 170, in _swap_proxies
    method(obj, attr, proxy)
  File "/Users/kaien/git/jsonpickle/jsonpickle/unpickler.py", line 105, in _obj_setvalue
    obj[idx] = proxy.get()
  File "/Users/kaien/git/jsonpickle/jsonpickle/unpickler.py", line 97, in get
    return self._objs[self._index]
IndexError: list index out of range


Traceback (most recent call last):
  File "/Users/kaien/git/jsonpickle/tests/defaultdict_check.py", line 25, in <module>
    decoded = jsonpickle.decode(encoded, keys=True)
  File "/Users/kaien/git/jsonpickle/jsonpickle/unpickler.py", line 41, in decode
    return context.restore(data, reset=reset, classes=classes)
  File "/Users/kaien/git/jsonpickle/jsonpickle/unpickler.py", line 150, in restore
    value = self._restore(obj)
  File "/Users/kaien/git/jsonpickle/jsonpickle/unpickler.py", line 207, in _restore
    return restore(obj)
  File "/Users/kaien/git/jsonpickle/jsonpickle/unpickler.py", line 323, in _restore_object
    return self._restore_object_instance(obj, cls)
  File "/Users/kaien/git/jsonpickle/jsonpickle/unpickler.py", line 388, in _restore_object_instance
    instance.default_factory = instance.default_factory.get()
  File "/Users/kaien/git/jsonpickle/jsonpickle/unpickler.py", line 97, in get
    return self._objs[self._index]
IndexError: list index out of range