E1136: False positive when used with typing (mypy) patterns

[ssbarnea]

Apparently even the master branch code does not yet play well with a common pattern used to add type hints. The linked example is not unique, the same pattern can be seen in many places.

While adding # pylint: disable=unsubscriptable-object can be used as a temporary workaround, it worth creating a bug as the more people will be adopting type hints, the more such problems we will face.

import os
from typing import TYPE_CHECKING, Any, Union

if TYPE_CHECKING:
    BasePathLike = os.PathLike[Any] # <-- that is where pylint identifies E1136
else:
    BasePathLike = os.PathLike

foo : Union[str, BasePathLike] = "bar"

Current behavior

example.py:5:19: E1136: Value 'os.PathLike' is unsubscriptable (unsubscriptable-object)

Expected behavior

Pass the linting as the code below is correct.

pylint --version output

2.6.0 and master, on python 3.9

[ajeetdsouza]

This failed for me too:

from typing import Optional
x: Optional[int]

[hippo91]

@ssbarnea thanks for your report. I can reproduce it.
@ajeetdsouza your issue is different from original one and has already been fixed thanks to #3890

[cdce8p]

This seems to be related to #3951
Which will be fixed with the next astroid update: pylint-dev/astroid#885

[hippo91]

@cdce8p thank you! I can confirm the bug is fixed. I can no longer reproduce it with current master branches of astroid and pylint.

[alkatar21]

I have the same message with exactly this code in Python 3.8 is this intentional or a bug?

pylint 2.12.2
astroid 2.9.3
Python 3.8.10

[Pierre-Sassoulas]

I can reproduce the issue again with python 3.8. It seems like the issue can be reintroduced easily in astroid and we'd need tests there too ideally.

[cdce8p]

The issue was indeed fixed, but only for Python 3.9+.
For 3.8, it's related to #4369, although with a different pattern.

[Avasam]

I'm not entirely certain if related, but I'm having the same issue with Column type from` the sqlalchemy typestubs
pylint 2.12.2
Python 3.9.6

from __future__ import annotations
from sqlalchemy import Column, DateTime, Integer, String

class Player(BaseModel):
    __tablename__ = "player"

    user_id = db.Column(db.String(8), primary_key=True)
    name = db.Column(db.String(32), nullable=False)
    # The biggest region code I found so far was "us/co/coloradosprings" at 21
    country_code = db.Column(db.String(24))
    score = db.Column(db.Integer, nullable=False)
    score_details = db.Column(db.String())
    last_update = db.Column(db.DateTime())
    rank: Optional[int] = None

    schedules = db.relationship("Schedule", back_populates="owner")

    @overload
    def __init__(  # type: ignore
        self,
        user_id: str | Column[String],
        name: str | Column[String],
        country_code: Optional[str | Column[String]],
        score: int | float | Column[Integer],
        last_update: Optional[str | Column[DateTime]],
        score_details: Optional[str | Column[String]] = ...,
        rank: Optional[int] = ...
    ): ...
    
[...]

[cdce8p]

I'm not entirely certain if related, but I'm having the same issue with Column type from` the sqlalchemy typestubs pylint 2.12.2 Python 3.9.6

@Avasam That shouldn't be an issue anymore. Please make sure to test the latest pylint release. Additionally, stringified annotations should be used (either "str | Column[String]" or from __future__ import annotations). Then no unsubscriptable-object warning is emitted.