NameError: name '_GenericAlias' is not defined when importing pydantic

[eykamp]

Checks

• I added a descriptive title to this issue
• I have searched (google, github) for similar issues and couldn't find anything
• I have read and followed the docs and still think this is a bug

Bug

It's pretty obvious I've done something stupid, but I can't even get pydantic to import.

If I downgrade to 1.7, it works, but 1.8 does not.

Code:

import pydantic

Error:

>>> import pydantic
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/plastic/.local/lib/python3.10/site-packages/pydantic/__init__.py", line 2, in <module>
    from . import dataclasses
  File "/home/plastic/.local/lib/python3.10/site-packages/pydantic/dataclasses.py", line 3, in <module>
    from .class_validators import gather_all_validators
  File "/home/plastic/.local/lib/python3.10/site-packages/pydantic/class_validators.py", line 8, in <module>
    from .errors import ConfigError
  File "/home/plastic/.local/lib/python3.10/site-packages/pydantic/errors.py", line 5, in <module>
    from .typing import display_as_type
  File "/home/plastic/.local/lib/python3.10/site-packages/pydantic/typing.py", line 23, in <module>
    from typing_extensions import Annotated, Literal
  File "/home/plastic/.local/lib/python3.10/site-packages/typing_extensions.py", line 2390, in <module>
    class _ConcatenateGenericAlias(list):
  File "/home/plastic/.local/lib/python3.10/site-packages/typing_extensions.py", line 2394, in _ConcatenateGenericAlias
    __class__ = _GenericAlias
NameError: name '_GenericAlias' is not defined
>>>

Output of python -c "import pydantic.utils; print(pydantic.utils.version_info())":

Same error as above (perhaps unsurprisingly)

Versions:

~$ python3 --version
Python 3.10.0a3
~$ pip freeze | grep pydantic
pydantic==1.8.2
~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 16.04.7 LTS
Release:        16.04
Codename:       xenial
~$

[iamthen0ise]

Hi!

It is a general issue in typing module. i think it should be resolved as far as this issue will be marked as fixed python/typing#865

[domdfcoding]

As a quick workaround downgrading typing-extensions to 3.10.0.0 or earlier should work.

python3 -m pip install typing-extensions==3.10.0.0

[PrettyWood]

Thanks people for answering! 🙏 Not an issue with pydantic