Remove more Python 3.8 cruft (#13787)

lib/ts_utils/metadata.py

@@ -5,6 +5,7 @@
 
 from __future__ import annotations
 
+import functools
 import re
 import urllib.parse
 from collections.abc import Mapping
@@ -19,7 +20,6 @@ from packaging.requirements import Requirement
 from packaging.specifiers import Specifier
 
 from .paths import PYPROJECT_PATH, STUBS_PATH, distribution_path
-from .utils import cache
 
 __all__ = [
     "NoSuchStubError",
@@ -42,7 +42,7 @@ def _is_list_of_strings(obj: object) -> TypeGuard[list[str]]:
     return isinstance(obj, list) and all(isinstance(item, str) for item in obj)
 
 
-@cache
+@functools.cache
 def _get_oldest_supported_python() -> str:
     with PYPROJECT_PATH.open("rb") as config:
         val = tomli.load(config)["tool"]["typeshed"]["oldest_supported_python"]
@@ -79,7 +79,7 @@ class StubtestSettings:
         return ret
 
 
-@cache
+@functools.cache
 def read_stubtest_settings(distribution: str) -> StubtestSettings:
     """Return an object describing the stubtest settings for a single stubs distribution."""
     with metadata_path(distribution).open("rb") as f:
@@ -187,7 +187,7 @@ class NoSuchStubError(ValueError):
     """Raise NoSuchStubError to indicate that a stubs/{distribution} directory doesn't exist."""
 
 
-@cache
+@functools.cache
 def read_metadata(distribution: str) -> StubMetadata:
     """Return an object describing the metadata of a stub as given in the METADATA.toml file.
 
@@ -328,12 +328,12 @@ class PackageDependencies(NamedTuple):
     external_pkgs: tuple[Requirement, ...]
 
 
-@cache
+@functools.cache
 def get_pypi_name_to_typeshed_name_mapping() -> Mapping[str, str]:
     return {read_metadata(stub_dir.name).stub_distribution: stub_dir.name for stub_dir in STUBS_PATH.iterdir()}
 
 
-@cache
+@functools.cache
 def read_dependencies(distribution: str) -> PackageDependencies:
     """Read the dependencies listed in a METADATA.toml file for a stubs package.
 
@@ -360,7 +360,7 @@ def read_dependencies(distribution: str) -> PackageDependencies:
     return PackageDependencies(tuple(typeshed), tuple(external))
 
 
-@cache
+@functools.cache
 def get_recursive_requirements(package_name: str) -> PackageDependencies:
     """Recursively gather dependencies for a single stubs package.
 

lib/ts_utils/utils.py

@@ -2,10 +2,10 @@
 
 from __future__ import annotations
 
+import functools
 import re
 import sys
 from collections.abc import Iterable, Mapping
-from functools import lru_cache
 from pathlib import Path
 from typing import Any, Final, NamedTuple
 from typing_extensions import TypeAlias
@@ -26,11 +26,6 @@ from .paths import REQUIREMENTS_PATH, STDLIB_PATH, STUBS_PATH, TEST_CASES_DIR, a
 PYTHON_VERSION: Final = f"{sys.version_info.major}.{sys.version_info.minor}"
 
 
-# A backport of functools.cache for Python <3.9
-# This module is imported by mypy_test.py, which needs to run on 3.8 in CI
-cache = lru_cache(None)
-
-
 def strip_comments(text: str) -> str:
     return text.split("#")[0].strip()
 
@@ -81,7 +76,7 @@ def print_time(t: float) -> None:
 # ====================================================================
 
 
-@cache
+@functools.cache
 def venv_python(venv_dir: Path) -> Path:
     if sys.platform == "win32":
         return venv_dir / "Scripts" / "python.exe"
@@ -93,7 +88,7 @@ def venv_python(venv_dir: Path) -> Path:
 # ====================================================================
 
 
-@cache
+@functools.cache
 def parse_requirements() -> Mapping[str, Requirement]:
     """Return a dictionary of requirements from the requirements file."""
     with REQUIREMENTS_PATH.open(encoding="UTF-8") as requirements_file:
@@ -206,7 +201,7 @@ def allowlists(distribution_name: str) -> list[str]:
 # ====================================================================
 
 
-@cache
+@functools.cache
 def get_gitignore_spec() -> pathspec.PathSpec:
     with open(".gitignore", encoding="UTF-8") as f:
         return pathspec.PathSpec.from_lines("gitwildmatch", f.readlines())