# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
# For details: https://github.com/PyCQA/pylint/blob/main/LICENSE
# Copyright (c) https://github.com/PyCQA/pylint/blob/main/CONTRIBUTORS.txt
"""Checker for features used that are not supported by all python versions
indicated by the py-version setting.
"""
from __future__ import annotations
from typing import TYPE_CHECKING
from astroid import nodes
from pylint.checkers import BaseChecker
from pylint.checkers.utils import (
only_required_for_messages,
safe_infer,
uninferable_final_decorators,
)
if TYPE_CHECKING:
from pylint.lint import PyLinter
class UnsupportedVersionChecker(BaseChecker):
"""Checker for features that are not supported by all python versions
indicated by the py-version setting.
"""
name = "unsupported_version"
msgs = {
"W2601": (
"F-strings are not supported by all versions included in the py-version setting",
"using-f-string-in-unsupported-version",
"Used when the py-version set by the user is lower than 3.6 and pylint encounters "
"a f-string.",
),
"W2602": (
"typing.final is not supported by all versions included in the py-version setting",
"using-final-decorator-in-unsupported-version",
"Used when the py-version set by the user is lower than 3.8 and pylint encounters "
"a ``typing.final`` decorator.",
),
}
def open(self) -> None:
"""Initialize visit variables and statistics."""
py_version = self.linter.config.py_version
self._py36_plus = py_version >= (3, 6)
self._py38_plus = py_version >= (3, 8)
@only_required_for_messages("using-f-string-in-unsupported-version")
def visit_joinedstr(self, node: nodes.JoinedStr) -> None:
"""Check f-strings."""
if not self._py36_plus:
self.add_message("using-f-string-in-unsupported-version", node=node)
@only_required_for_messages("using-final-decorator-in-unsupported-version")
def visit_decorators(self, node: nodes.Decorators) -> None:
"""Check decorators."""
self._check_typing_final(node)
def _check_typing_final(self, node: nodes.Decorators) -> None:
"""Add a message when the `typing.final` decorator is used and the
py-version is lower than 3.8.
"""
if self._py38_plus:
return
decorators = []
for decorator in node.get_children():
inferred = safe_infer(decorator)
if inferred and inferred.qname() == "typing.final":
decorators.append(decorator)
for decorator in decorators or uninferable_final_decorators(node):
self.add_message(
"using-final-decorator-in-unsupported-version", node=decorator
)
def register(linter: PyLinter) -> None:
linter.register_checker(UnsupportedVersionChecker(linter))
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