Nested class serialization breaks with future annotations import

[sizmailov]

Minimal code to reproduce:

from __future__ import annotations # <-- Brings troubles
from dataclasses import dataclass
from mashumaro import DataClassDictMixin


@dataclass
class Root(DataClassDictMixin):
    @dataclass
    class Nested(DataClassDictMixin):
        x: int

    nested: Nested


cfg = Root.from_dict({"nested": {"x": 1}}) 

print(cfg)

Traceback [python==3.9.5 / mashumaro==2.9.1]:

Traceback (most recent call last):
  File "bug.py", line 15, in <module>
    cfg = Root.from_dict({"nested": {"x": 1}})
  File "<path-to-venv>/lib/python3.9/site-packages/mashumaro/serializer/base/dict.py", line 50, in from_dict
    builder.add_from_dict()
  File "<path-to-venv>/lib/python3.9/site-packages/mashumaro/serializer/base/metaprogramming.py", line 282, in add_from_dict
    for fname, ftype in self.field_types.items():
  File "<path-to-venv>/lib/python3.9/site-packages/mashumaro/serializer/base/metaprogramming.py", line 178, in field_types
    return self.__get_field_types()
  File "<path-to-venv>/lib/python3.9/site-packages/mashumaro/serializer/base/metaprogramming.py", line 152, in __get_field_types
    raise UnresolvedTypeReferenceError(self.cls, name) from None
mashumaro.exceptions.UnresolvedTypeReferenceError: Class Root has unresolved type reference Nested in some of its fields

Code runs fine without from __future__ import annotations line.

Note: with DataClassYAMLMixin you get a rather cryptic error message:

Traceback (most recent call last):
  File "bug-yml.py", line 14, in <module>
    cfg = Root.from_yaml("""
  File "<path-to-venv>/lib/python3.9/site-packages/mashumaro/serializer/yaml.py", line 51, in from_yaml
    return cls.from_dict(
  File "<string>", line 10, in from_dict
TypeError: __init__() missing 1 required positional argument: 'nested'

[Fatal1ty]

Hi @sizmailov

I see this can't be reproduced on 3.10. But on the previous versions it could be fixed by adding self.cls.__dict__ to typing.get_type_hints here as suggested here https://bugs.python.org/issue42829#msg384423. I'll see if there's any problem with that.

[sizmailov]

I confirm, bug affects 3.8, 3.9, but not 3.10.
Interesting. The bug marked as "won't fix" disappears in next release 🙃

[Fatal1ty]

Fixed in 2.10.

[sizmailov]

Fixed in 2.10.

Just tried new release. Looks like the initial snippet still fails with mashumaro==2.10 with python 3.8 and 3.9...

Traceback

Traceback (most recent call last):
  File "/tmp/bug/main.py", line 15, in <module>
    cfg = Root.from_dict({"nested": {"x": 1}})
  File "/tmp/bug/venv-3.9/lib/python3.9/site-packages/mashumaro/serializer/base/dict.py", line 55, in from_dict
    builder.add_from_dict()
  File "/tmp/bug/venv-3.9/lib/python3.9/site-packages/mashumaro/serializer/base/metaprogramming.py", line 375, in add_from_dict
    return self._add_from_dict()
  File "/tmp/bug/venv-3.9/lib/python3.9/site-packages/mashumaro/serializer/base/metaprogramming.py", line 288, in _add_from_dict
    self._add_from_dict_lines()
  File "/tmp/bug/venv-3.9/lib/python3.9/site-packages/mashumaro/serializer/base/metaprogramming.py", line 311, in _add_from_dict_lines
    for fname, ftype in self.field_types.items():
  File "/tmp/bug/venv-3.9/lib/python3.9/site-packages/mashumaro/serializer/base/metaprogramming.py", line 194, in field_types
    return self.__get_field_types()
  File "/tmp/bug/venv-3.9/lib/python3.9/site-packages/mashumaro/serializer/base/metaprogramming.py", line 168, in __get_field_types
    raise UnresolvedTypeReferenceError(self.cls, name) from None
mashumaro.exceptions.UnresolvedTypeReferenceError: Class Root has unresolved type reference Nested in some of its fields

[Fatal1ty]

Oops, I forgot to merge the branch. You can check the version 2.10.1 :)