Textual type hints crash deserialization

[ramonhagenaars]

This issue is possibly related Issue#26.

Textual type hints cannot be deserialized as jsons does not handle string type hints well. This makes it impossible to deserialize into a recursive structure.

Example:

from dataclasses import dataclass
from typing import Optional
import jsons


@dataclass
class Node:
    value: object
    next: Optional['Node']


linked_list = Node(10, Node(20, Node(30, None)))
dumped = jsons.dump(linked_list)

So far so good. The value of dumped is now:

{'next': {'next': {'next': None, 'value': 30}, 'value': 20}, 'value': 10}

Now to deserialize:

jsons.load(dumped, Node)

This raises the following error:

Traceback (most recent call last):
  File "C:\Projects\Personal\jsons\jsons\_main_impl.py", line 128, in load
    return deserializer(json_obj, cls, **kwargs_)
  File "C:\Projects\Personal\jsons\jsons\deserializers\default_object.py", line 31, in default_object_deserializer
    constructor_args = _get_constructor_args(obj, cls, **kwargs)
  File "C:\Projects\Personal\jsons\jsons\deserializers\default_object.py", line 58, in _get_constructor_args
    constructor_args_in_obj = {key: value for key, value in args_gen if key}
  File "C:\Projects\Personal\jsons\jsons\deserializers\default_object.py", line 58, in <dictcomp>
    constructor_args_in_obj = {key: value for key, value in args_gen if key}
  File "C:\Projects\Personal\jsons\jsons\deserializers\default_object.py", line 57, in <genexpr>
    in signature_parameters.items() if sig_key != 'self')
  File "C:\Projects\Personal\jsons\jsons\deserializers\default_object.py", line 72, in _get_value_for_attr
    if obj and sig_key in obj:
TypeError: argument of type 'int' is not iterable

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:/Projects/Personal/jsons/effe.py", line 20, in <module>
    jsons.load(dumped, Node)
  File "C:\Projects\Personal\jsons\jsons\_main_impl.py", line 128, in load
    return deserializer(json_obj, cls, **kwargs_)
  File "C:\Projects\Personal\jsons\jsons\deserializers\default_object.py", line 31, in default_object_deserializer
    constructor_args = _get_constructor_args(obj, cls, **kwargs)
  File "C:\Projects\Personal\jsons\jsons\deserializers\default_object.py", line 58, in _get_constructor_args
    constructor_args_in_obj = {key: value for key, value in args_gen if key}
  File "C:\Projects\Personal\jsons\jsons\deserializers\default_object.py", line 58, in <dictcomp>
    constructor_args_in_obj = {key: value for key, value in args_gen if key}
  File "C:\Projects\Personal\jsons\jsons\deserializers\default_object.py", line 57, in <genexpr>
    in signature_parameters.items() if sig_key != 'self')
  File "C:\Projects\Personal\jsons\jsons\deserializers\default_object.py", line 75, in _get_value_for_attr
    meta_hints, **kwargs)
  File "C:\Projects\Personal\jsons\jsons\deserializers\default_object.py", line 109, in _get_value_from_obj
    value = load(obj[sig_key], arg_cls, meta_hints=new_hints, **kwargs)
  File "C:\Projects\Personal\jsons\jsons\_main_impl.py", line 132, in load
    raise DeserializationError(str(err), json_obj, cls)
jsons.exceptions.DeserializationError: argument of type 'int' is not iterable

[ramonhagenaars]

This has been solved in 0.8.4.