Use __future__.annotations (#2433)

* Use `__future__.annotations`

* fix linter

starlette/_exception_handler.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import typing
 
 from starlette._utils import is_async_callable
@@ -22,16 +24,14 @@
 
 def _lookup_exception_handler(
     exc_handlers: ExceptionHandlers, exc: Exception
-) -> typing.Optional[ExceptionHandler]:
+) -> ExceptionHandler | None:
     for cls in type(exc).__mro__:
         if cls in exc_handlers:
             return exc_handlers[cls]
     return None
 
 
-def wrap_app_handling_exceptions(
-    app: ASGIApp, conn: typing.Union[Request, WebSocket]
-) -> ASGIApp:
+def wrap_app_handling_exceptions(app: ASGIApp, conn: Request | WebSocket) -> ASGIApp:
     exception_handlers: ExceptionHandlers
     status_handlers: StatusHandlers
     try:

starlette/_utils.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import asyncio
 import functools
 import re
@@ -74,7 +76,7 @@ async def __aenter__(self) -> SupportsAsyncCloseType:
         self.entered = await self.aw
         return self.entered
 
-    async def __aexit__(self, *args: typing.Any) -> typing.Union[None, bool]:
+    async def __aexit__(self, *args: typing.Any) -> None | bool:
         await self.entered.close()
         return None
 

starlette/applications.py

@@ -55,14 +55,14 @@ class Starlette:
     """
 
     def __init__(
-        self: "AppType",
+        self: AppType,
         debug: bool = False,
         routes: typing.Sequence[BaseRoute] | None = None,
         middleware: typing.Sequence[Middleware] | None = None,
         exception_handlers: typing.Mapping[typing.Any, ExceptionHandler] | None = None,
         on_startup: typing.Sequence[typing.Callable[[], typing.Any]] | None = None,
         on_shutdown: typing.Sequence[typing.Callable[[], typing.Any]] | None = None,
-        lifespan: typing.Optional[Lifespan["AppType"]] = None,
+        lifespan: Lifespan[AppType] | None = None,
     ) -> None:
         # The lifespan context function is a newer style that replaces
         # on_startup / on_shutdown handlers. Use one or the other, not both.
@@ -84,7 +84,7 @@ def __init__(
     def build_middleware_stack(self) -> ASGIApp:
         debug = self.debug
         error_handler = None
-        exception_handlers: typing.Dict[
+        exception_handlers: dict[
             typing.Any, typing.Callable[[Request, Exception], Response]
         ] = {}
 
@@ -110,7 +110,7 @@ def build_middleware_stack(self) -> ASGIApp:
         return app
 
     @property
-    def routes(self) -> typing.List[BaseRoute]:
+    def routes(self) -> list[BaseRoute]:
         return self.router.routes
 
     def url_path_for(self, name: str, /, **path_params: typing.Any) -> URLPath:
@@ -193,7 +193,7 @@ def decorator(func: typing.Callable) -> typing.Callable:  # type: ignore[type-ar
     def route(
         self,
         path: str,
-        methods: typing.List[str] | None = None,
+        methods: list[str] | None = None,
         name: str | None = None,
         include_in_schema: bool = True,
     ) -> typing.Callable:  # type: ignore[type-arg]

starlette/authentication.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import functools
 import inspect
 import sys
@@ -26,9 +28,9 @@ def has_required_scope(conn: HTTPConnection, scopes: typing.Sequence[str]) -> bo
 
 
 def requires(
-    scopes: typing.Union[str, typing.Sequence[str]],
+    scopes: str | typing.Sequence[str],
     status_code: int = 403,
-    redirect: typing.Optional[str] = None,
+    redirect: str | None = None,
 ) -> typing.Callable[
     [typing.Callable[_P, typing.Any]], typing.Callable[_P, typing.Any]
 ]:
@@ -113,12 +115,12 @@ class AuthenticationError(Exception):
 class AuthenticationBackend:
     async def authenticate(
         self, conn: HTTPConnection
-    ) -> typing.Optional[typing.Tuple["AuthCredentials", "BaseUser"]]:
+    ) -> tuple[AuthCredentials, BaseUser] | None:
         raise NotImplementedError()  # pragma: no cover
 
 
 class AuthCredentials:
-    def __init__(self, scopes: typing.Optional[typing.Sequence[str]] = None):
+    def __init__(self, scopes: typing.Sequence[str] | None = None):
         self.scopes = [] if scopes is None else list(scopes)
 
 

starlette/background.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import sys
 import typing
 
@@ -29,7 +31,7 @@ async def __call__(self) -> None:
 
 
 class BackgroundTasks(BackgroundTask):
-    def __init__(self, tasks: typing.Optional[typing.Sequence[BackgroundTask]] = None):
+    def __init__(self, tasks: typing.Sequence[BackgroundTask] | None = None):
         self.tasks = list(tasks) if tasks else []
 
     def add_task(

starlette/concurrency.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import functools
 import sys
 import typing
@@ -14,7 +16,7 @@
 T = typing.TypeVar("T")
 
 
-async def run_until_first_complete(*args: typing.Tuple[typing.Callable, dict]) -> None:  # type: ignore[type-arg]  # noqa: E501
+async def run_until_first_complete(*args: tuple[typing.Callable, dict]) -> None:  # type: ignore[type-arg]  # noqa: E501
     warnings.warn(
         "run_until_first_complete is deprecated "
         "and will be removed in a future version.",

starlette/config.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import os
 import typing
 from pathlib import Path
@@ -51,7 +53,7 @@ def __len__(self) -> int:
 class Config:
     def __init__(
         self,
-        env_file: typing.Optional[typing.Union[str, Path]] = None,
+        env_file: str | Path | None = None,
         environ: typing.Mapping[str, str] = environ,
         env_prefix: str = "",
     ) -> None:
@@ -64,17 +66,15 @@ def __init__(
             self.file_values = self._read_file(env_file)
 
     @typing.overload
-    def __call__(self, key: str, *, default: None) -> typing.Optional[str]:
+    def __call__(self, key: str, *, default: None) -> str | None:
         ...
 
     @typing.overload
-    def __call__(self, key: str, cast: typing.Type[T], default: T = ...) -> T:
+    def __call__(self, key: str, cast: type[T], default: T = ...) -> T:
         ...
 
     @typing.overload
-    def __call__(
-        self, key: str, cast: typing.Type[str] = ..., default: str = ...
-    ) -> str:
+    def __call__(self, key: str, cast: type[str] = ..., default: str = ...) -> str:
         ...
 
     @typing.overload
@@ -87,23 +87,21 @@ def __call__(
         ...
 
     @typing.overload
-    def __call__(
-        self, key: str, cast: typing.Type[str] = ..., default: T = ...
-    ) -> typing.Union[T, str]:
+    def __call__(self, key: str, cast: type[str] = ..., default: T = ...) -> T | str:
         ...
 
     def __call__(
         self,
         key: str,
-        cast: typing.Optional[typing.Callable[[typing.Any], typing.Any]] = None,
+        cast: typing.Callable[[typing.Any], typing.Any] | None = None,
         default: typing.Any = undefined,
     ) -> typing.Any:
         return self.get(key, cast, default)
 
     def get(
         self,
         key: str,
-        cast: typing.Optional[typing.Callable[[typing.Any], typing.Any]] = None,
+        cast: typing.Callable[[typing.Any], typing.Any] | None = None,
         default: typing.Any = undefined,
     ) -> typing.Any:
         key = self.env_prefix + key
@@ -117,7 +115,7 @@ def get(
             return self._perform_cast(key, default, cast)
         raise KeyError(f"Config '{key}' is missing, and has no default.")
 
-    def _read_file(self, file_name: typing.Union[str, Path]) -> typing.Dict[str, str]:
+    def _read_file(self, file_name: str | Path) -> dict[str, str]:
         file_values: typing.Dict[str, str] = {}
         with open(file_name) as input_file:
             for line in input_file.readlines():
@@ -133,7 +131,7 @@ def _perform_cast(
         self,
         key: str,
         value: typing.Any,
-        cast: typing.Optional[typing.Callable[[typing.Any], typing.Any]] = None,
+        cast: typing.Callable[[typing.Any], typing.Any] | None = None,
     ) -> typing.Any:
         if cast is None or value is None:
             return value