Remove more Python 3.8 cruft (#13787)

AlexWaygood · web-flow · commit d92a6449c241 · 2025-04-03T11:56:38.000+01:00
diff --git a/lib/ts_utils/metadata.py b/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.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 @@ def system_requirements_for_platform(self, platform: str) -> list[str]:
         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.
 
diff --git a/lib/ts_utils/utils.py b/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 @@ def colored(text: str, color: str | None = None, **kwargs: Any) -> str:  # type:
 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())
diff --git a/pyproject.toml b/pyproject.toml
@@ -18,7 +18,7 @@ force-exclude = ".*_pb2.pyi"
 [tool.ruff]
 line-length = 130
 # Oldest supported Python version
-target-version = "py38"
+target-version = "py39"
 fix = true
 exclude = [
     # virtual environment
diff --git a/scripts/stubsabot.py b/scripts/stubsabot.py
@@ -730,8 +730,6 @@ async def suggest_typeshed_obsolete(obsolete: Obsolete, session: aiohttp.ClientS
 
 
 async def main() -> None:
-    assert sys.version_info >= (3, 9)
-
     parser = argparse.ArgumentParser()
     parser.add_argument(
         "--action-level",
diff --git a/stdlib/@tests/stubtest_allowlists/darwin-py39.txt b/stdlib/@tests/stubtest_allowlists/darwin-py39.txt
@@ -10,9 +10,9 @@ email.utils.getaddresses
 email.utils.parseaddr
 
 
-# ======
-# <= 3.9
-# ======
+# ========
+# 3.9 only
+# ========
 
 # Added in Python 3.9.14
 sys.set_int_max_str_digits
diff --git a/stdlib/@tests/stubtest_allowlists/linux-py39.txt b/stdlib/@tests/stubtest_allowlists/linux-py39.txt
@@ -1,6 +1,6 @@
-# ======
-# <= 3.9
-# ======
+# ========
+# 3.9 only
+# ========
 
 # `eventmask` argument exists at runtime, but is not correctly recognized
 # while being inspected by stubtest. Fixed in Python 3.10.
diff --git a/stdlib/@tests/stubtest_allowlists/py39.txt b/stdlib/@tests/stubtest_allowlists/py39.txt
@@ -1,8 +1,3 @@
-# ========================
-# New errors in Python 3.9
-# ========================
-
-
 # ========
 # 3.9 only
 # ========
@@ -16,24 +11,7 @@ collections.MappingView.__class_getitem__
 hmac.HMAC.digest_cons
 hmac.HMAC.inner
 hmac.HMAC.outer
-
-
-# ===========
-# 3.9 to 3.10
-# ===========
-
-builtins.float.__setformat__  # Internal method for CPython test suite
-typing._SpecialForm.__mro_entries__  # Exists at runtime, but missing from stubs
-
-
-# ===================================
-# Pre-existing errors from Python 3.8
-# ===================================
-
-
-# ======
-# <= 3.9
-# ======
+xxsubtype  # module missing from the stubs
 
 builtins.input  # Incorrect default value in text signature, fixed in 3.10
 collections.AsyncGenerator.__anext__  # async at runtime, deliberately not in the stub, see #7491
@@ -44,13 +22,13 @@ collections.ByteString  # see comments in py3_common.txt
 collections.Callable
 collections.Mapping.get  # Adding None to the Union messed up mypy
 collections.Sequence.index  # Supporting None in end is not mandatory
-xxsubtype  # module missing from the stubs
-
 
-# =======
+# ===========
 # <= 3.10
-# =======
+# ===========
 
+builtins.float.__setformat__  # Internal method for CPython test suite
+typing._SpecialForm.__mro_entries__  # Exists at runtime, but missing from stubs
 email.contentmanager.typ
 gettext.install  # codeset default value is ['unspecified'] so can't be specified
 gettext.translation  # codeset default value is ['unspecified'] so can't be specified
diff --git a/stdlib/@tests/stubtest_allowlists/win32-py39.txt b/stdlib/@tests/stubtest_allowlists/win32-py39.txt
@@ -11,9 +11,9 @@ email.utils.getaddresses
 email.utils.parseaddr
 
 
-# ======
-# <= 3.9
-# ======
+# ========
+# 3.9 only
+# ========
 
 # Added in Python 3.9.14
 sys.set_int_max_str_digits
diff --git a/stdlib/VERSIONS b/stdlib/VERSIONS
@@ -145,7 +145,6 @@ encodings.cp273: 3.4-
 encodings.cp858: 3.2-
 encodings.koi8_t: 3.5-
 encodings.kz1048: 3.5-
-encodings.mac_centeuro: 3.0-3.8
 ensurepip: 3.0-
 enum: 3.4-
 errno: 3.0-
diff --git a/stdlib/_collections_abc.pyi b/stdlib/_collections_abc.pyi
@@ -1,7 +1,7 @@
 import sys
 from abc import abstractmethod
 from types import MappingProxyType
-from typing import (  # noqa: Y022,Y038
+from typing import (  # noqa: Y022,Y038,UP035
     AbstractSet as Set,
     AsyncGenerator as AsyncGenerator,
     AsyncIterable as AsyncIterable,
@@ -61,7 +61,7 @@ __all__ = [
     "MutableSequence",
 ]
 if sys.version_info < (3, 14):
-    from typing import ByteString as ByteString  # noqa: Y057
+    from typing import ByteString as ByteString  # noqa: Y057,UP035
 
     __all__ += ["ByteString"]
 
diff --git a/stdlib/array.pyi b/stdlib/array.pyi
@@ -1,14 +1,10 @@
 import sys
 from _typeshed import ReadableBuffer, SupportsRead, SupportsWrite
-from collections.abc import Iterable
-
-# pytype crashes if array inherits from collections.abc.MutableSequence instead of typing.MutableSequence
-from typing import Any, ClassVar, Literal, MutableSequence, SupportsIndex, TypeVar, overload  # noqa: Y022
+from collections.abc import Iterable, MutableSequence
+from types import GenericAlias
+from typing import Any, ClassVar, Literal, SupportsIndex, TypeVar, overload
 from typing_extensions import Self, TypeAlias
 
-if sys.version_info >= (3, 12):
-    from types import GenericAlias
-
 _IntTypeCode: TypeAlias = Literal["b", "B", "h", "H", "i", "I", "l", "L", "q", "Q"]
 _FloatTypeCode: TypeAlias = Literal["f", "d"]
 _UnicodeTypeCode: TypeAlias = Literal["u"]
diff --git a/stdlib/builtins.pyi b/stdlib/builtins.pyi
@@ -36,7 +36,7 @@ from types import CellType, CodeType, GenericAlias, TracebackType
 
 # mypy crashes if any of {ByteString, Sequence, MutableSequence, Mapping, MutableMapping}
 # are imported from collections.abc in builtins.pyi
-from typing import (  # noqa: Y022
+from typing import (  # noqa: Y022,UP035
     IO,
     Any,
     BinaryIO,
diff --git a/stdlib/csv.pyi b/stdlib/csv.pyi
@@ -26,12 +26,10 @@ else:
 
 from _typeshed import SupportsWrite
 from collections.abc import Collection, Iterable, Mapping, Sequence
+from types import GenericAlias
 from typing import Any, Generic, Literal, TypeVar, overload
 from typing_extensions import Self
 
-if sys.version_info >= (3, 12):
-    from types import GenericAlias
-
 __all__ = [
     "QUOTE_MINIMAL",
     "QUOTE_ALL",
diff --git a/stdlib/encodings/mac_centeuro.pyi b/stdlib/encodings/mac_centeuro.pyi
diff --git a/stdlib/logging/__init__.pyi b/stdlib/logging/__init__.pyi
@@ -6,13 +6,10 @@ from io import TextIOWrapper
 from re import Pattern
 from string import Template
 from time import struct_time
-from types import FrameType, TracebackType
+from types import FrameType, GenericAlias, TracebackType
 from typing import Any, ClassVar, Final, Generic, Literal, Protocol, TextIO, TypeVar, overload
 from typing_extensions import Self, TypeAlias, deprecated
 
-if sys.version_info >= (3, 11):
-    from types import GenericAlias
-
 __all__ = [
     "BASIC_FORMAT",
     "BufferingFormatter",
diff --git a/stdlib/types.pyi b/stdlib/types.pyi
@@ -11,13 +11,14 @@ from collections.abc import (
     Iterable,
     Iterator,
     KeysView,
+    Mapping,  # noqa: Y022
     MutableSequence,
     ValuesView,
 )
 from importlib.machinery import ModuleSpec
 
 # pytype crashes if types.MappingProxyType inherits from collections.abc.Mapping instead of typing.Mapping
-from typing import Any, ClassVar, Literal, Mapping, TypeVar, final, overload  # noqa: Y022
+from typing import Any, ClassVar, Literal, TypeVar, final, overload
 from typing_extensions import ParamSpec, Self, TypeAliasType, TypeVarTuple, deprecated
 
 __all__ = [
diff --git a/stdlib/typing_extensions.pyi b/stdlib/typing_extensions.pyi
diff --git a/tests/check_typeshed_structure.py b/tests/check_typeshed_structure.py
diff --git a/tests/mypy_test.py b/tests/mypy_test.py
