src/attr/_compat.py - main - niceSOFT/python3-attrs

src/attr/_compat.py
127 строк3 KB
Hynek Schlawack
Drop Python 3.9 (#1603)
02 авг 2026, 12:06
02 авг 2026, 12:069b98a73
# SPDX-License-Identifier: MIT

import sys
import threading

from collections.abc import Mapping, Sequence  # noqa: F401
from typing import Callable, _GenericAlias


PYPY = sys.implementation.name == "pypy"
PY_3_11_PLUS = sys.version_info[:2] >= (3, 11)
PY_3_12_PLUS = sys.version_info[:2] >= (3, 12)
PY_3_13_PLUS = sys.version_info[:2] >= (3, 13)
PY_3_14_PLUS = sys.version_info[:2] >= (3, 14)


if PY_3_14_PLUS:
    # We request forward-ref annotations to not break in the presence of
    # forward references.

    def _get_annotations(cls):
        import annotationlib

        return annotationlib.get_annotations(
            cls, format=annotationlib.Format.FORWARDREF
        )

else:

    def _get_annotations(cls):
        """
        Get annotations for *cls*.
        """
        return cls.__dict__.get("__annotations__", {})  # noqa: RUF063


class _AnnotationExtractor:
    """
    Extract type annotations from a callable, returning None whenever there
    is none.
    """

    __slots__ = ["sig"]

    def __init__(self, callable):
        import inspect

        try:
            self.sig = inspect.signature(callable)
        except (ValueError, TypeError):  # inspect failed
            self.sig = None

    def get_first_param_type(self):
        """
        Return the type annotation of the first argument if it's not empty.
        """
        import inspect

        if not self.sig:
            return None

        params = list(self.sig.parameters.values())
        if params and params[0].annotation is not inspect.Parameter.empty:
            return params[0].annotation

        return None

    def get_return_type(self):
        """
        Return the return type if it's not empty.
        """
        import inspect

        if (
            self.sig
            and self.sig.return_annotation is not inspect.Signature.empty
        ):
            return self.sig.return_annotation

        return None


# Thread-local global to track attrs instances which are already being repr'd.
# This is needed because there is no other (thread-safe) way to pass info
# about the instances that are already being repr'd through the call stack
# in order to ensure we don't perform infinite recursion.
#
# For instance, if an instance contains a dict which contains that instance,
# we need to know that we're already repr'ing the outside instance from within
# the dict's repr() call.
#
# This lives here rather than in _make.py so that the functions in _make.py
# don't have a direct reference to the thread-local in their globals dict.
# If they have such a reference, it breaks cloudpickle.
repr_context = threading.local()


def get_generic_base(cl):
    """If this is a generic class (A[str]), return the generic base for it."""
    if cl.__class__ is _GenericAlias:
        return cl.__origin__
    return None


_IS_GENERATOR_RESULTS = {}


def _lazy_is_generator(f: Callable) -> Callable[[], bool]:
    """
    Return a caching closure over callable f that returns whether f is a
    generator function.

    Not thread-safe but doesn't matter.
    """

    def is_gen() -> bool:
        import inspect

        try:
            if f not in _IS_GENERATOR_RESULTS:
                _IS_GENERATOR_RESULTS[f] = inspect.isgeneratorfunction(f)
        except TypeError:  # f is not hashable
            return inspect.isgeneratorfunction(f)

        return _IS_GENERATOR_RESULTS[f]

    return is_gen