Remove Python 3.8 exclusive branches from _asyncio, _blake2, _codecs, _contextvars (#13773)

Remove 3.8 exclusive branches from asyncio, _blake2, codecs, contextvars

stdlib/_asyncio.pyi

@@ -2,13 +2,10 @@ import sys
 from asyncio.events import AbstractEventLoop
 from collections.abc import Awaitable, Callable, Coroutine, Generator
 from contextvars import Context
-from types import FrameType
+from types import FrameType, GenericAlias
 from typing import Any, Literal, TextIO, TypeVar
 from typing_extensions import Self, TypeAlias
 
-if sys.version_info >= (3, 9):
-    from types import GenericAlias
-
 _T = TypeVar("_T")
 _T_co = TypeVar("_T_co", covariant=True)
 _TaskYieldType: TypeAlias = Future[object] | None
@@ -29,11 +26,7 @@ class Future(Awaitable[_T]):
     @property
     def _callbacks(self) -> list[tuple[Callable[[Self], Any], Context]]: ...
     def add_done_callback(self, fn: Callable[[Self], object], /, *, context: Context | None = None) -> None: ...
-    if sys.version_info >= (3, 9):
-        def cancel(self, msg: Any | None = None) -> bool: ...
-    else:
-        def cancel(self) -> bool: ...
-
+    def cancel(self, msg: Any | None = None) -> bool: ...
     def cancelled(self) -> bool: ...
     def done(self) -> bool: ...
     def result(self) -> _T: ...
@@ -45,15 +38,12 @@ class Future(Awaitable[_T]):
     def __await__(self) -> Generator[Any, None, _T]: ...
     @property
     def _loop(self) -> AbstractEventLoop: ...
-    if sys.version_info >= (3, 9):
-        def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
+    def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
 
 if sys.version_info >= (3, 12):
     _TaskCompatibleCoro: TypeAlias = Coroutine[Any, Any, _T_co]
-elif sys.version_info >= (3, 9):
-    _TaskCompatibleCoro: TypeAlias = Generator[_TaskYieldType, None, _T_co] | Coroutine[Any, Any, _T_co]
 else:
-    _TaskCompatibleCoro: TypeAlias = Generator[_TaskYieldType, None, _T_co] | Awaitable[_T_co]
+    _TaskCompatibleCoro: TypeAlias = Generator[_TaskYieldType, None, _T_co] | Coroutine[Any, Any, _T_co]
 
 # mypy and pyright complain that a subclass of an invariant class shouldn't be covariant.
 # While this is true in general, here it's sort-of okay to have a covariant subclass,
@@ -99,13 +89,8 @@ class Task(Future[_T_co]):  # type: ignore[type-var]  # pyright: ignore[reportIn
     if sys.version_info >= (3, 11):
         def cancelling(self) -> int: ...
         def uncancel(self) -> int: ...
-    if sys.version_info < (3, 9):
-        @classmethod
-        def current_task(cls, loop: AbstractEventLoop | None = None) -> Task[Any] | None: ...
-        @classmethod
-        def all_tasks(cls, loop: AbstractEventLoop | None = None) -> set[Task[Any]]: ...
-    if sys.version_info >= (3, 9):
-        def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
+
+    def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
 
 def get_event_loop() -> AbstractEventLoop: ...
 def get_running_loop() -> AbstractEventLoop: ...