Pydantic: tests failing on 3.8

[samuelcolvin]

Two tests are failing with python 3.8 on CI:

• test_initvars_post_init
• test_initvars_post_init_post_parse

We should fix this since 3.8 is close to release. Any help would be much appreciated, I'll looked quickly but can't quite seem what's wrong.

traceback:

―――――――――――――――――――――― test_initvars_post_init_post_parse ――――――――――――――――――――――
    def test_initvars_post_init_post_parse():
        @pydantic.dataclasses.dataclass
>       class PathDataPostInitPostParse:
tests/test_dataclasses.py:504: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
pydantic/dataclasses.py:137: in dataclass
    return wrap(_cls)
pydantic/dataclasses.py:132: in wrap
    return _process_class(cls, init, repr, eq, order, unsafe_hash, frozen, config)
pydantic/dataclasses.py:84: in _process_class
    cls = dataclasses._process_class(_cls, init, repr, eq, order, unsafe_hash, frozen)  # type: ignore
/opt/python/3.8-dev/lib/python3.8/dataclasses.py:967: in _process_class
    str(inspect.signature(cls)).replace(' -> None', ''))
/opt/python/3.8-dev/lib/python3.8/inspect.py:3050: in __str__
    formatted = str(param)
/opt/python/3.8-dev/lib/python3.8/inspect.py:2568: in __str__
    formatannotation(self._annotation))
/opt/python/3.8-dev/lib/python3.8/inspect.py:1202: in formatannotation
    return repr(annotation)
/opt/python/3.8-dev/lib/python3.8/dataclasses.py:213: in __repr__
    return f'dataclasses.InitVar[{self.type.__name__}]'
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
self = typing.Union[pathlib.Path, NoneType], attr = '__name__'
    def __getattr__(self, attr):
        # We are careful for copy and pickle.
        # Also for simplicity we just don't relay all dunder names
        if '__origin__' in self.__dict__ and not _is_dunder(attr):
            return getattr(self.__origin__, attr)
>       raise AttributeError(attr)
E       AttributeError: __name__
/opt/python/3.8-dev/lib/python3.8/typing.py:757: AttributeError

[koxudaxi]

I gusses this is a bug on python3.8 rc1.
It's happened error when we call repr() with InitVar include Optional
python3.8 --version
Python 3.8.0rc1

from dataclasses import InitVar
from typing import Optional

print(repr(InitVar[str]))   # no error 
# > 'dataclasses.InitVar[str]'


print(repr(InitVar[Optional[str]]))  # error
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/dataclasses.py", line 213, in __repr__
    return f'dataclasses.InitVar[{self.type.__name__}]'
  File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/typing.py", line 757, in __getattr__
    raise AttributeError(attr)
AttributeError: __name__

PR:
https://github.com/python/cpython/commit/01ee12ba35a333e8a6a25c4153c4a21838e9585c

changelog:
https://docs.python.org/3.8/whatsnew/changelog.html#python-3-8-0-release-candidate-1

[samuelcolvin]

yes, I just created an issue.

Working on a fix now.

[koxudaxi]

Great work!!
It was too late to watch the code 🤣

[samuelcolvin]

merged and backported to 3.8, just waiting for the new rc to close this.