Enforce __future__.annotations (#2483)

pyproject.toml

@@ -9,9 +9,7 @@ description = "The little ASGI library that shines."
 readme = "README.md"
 license = "BSD-3-Clause"
 requires-python = ">=3.8"
-authors = [
-    { name = "Tom Christie", email = "[email protected]" },
-]
+authors = [{ name = "Tom Christie", email = "[email protected]" }]
 classifiers = [
     "Development Status :: 3 - Alpha",
     "Environment :: Web Environment",
@@ -52,7 +50,7 @@ Source = "https://github.com/encode/starlette"
 path = "starlette/__init__.py"
 
 [tool.ruff.lint]
-select = ["E", "F", "I"]
+select = ["E", "F", "I", "FA", "UP"]
 
 [tool.ruff.lint.isort]
 combine-as-imports = true
@@ -83,10 +81,7 @@ filterwarnings = [
 ]
 
 [tool.coverage.run]
-source_pkgs = [
-    "starlette",
-    "tests",
-]
+source_pkgs = ["starlette", "tests"]
 
 [tool.coverage.report]
 exclude_lines = [

starlette/applications.py

@@ -79,7 +79,7 @@ def __init__(
             {} if exception_handlers is None else dict(exception_handlers)
         )
         self.user_middleware = [] if middleware is None else list(middleware)
-        self.middleware_stack: typing.Optional[ASGIApp] = None
+        self.middleware_stack: ASGIApp | None = None
 
     def build_middleware_stack(self) -> ASGIApp:
         debug = self.debug
@@ -133,7 +133,7 @@ def host(self, host: str, app: ASGIApp, name: str | None = None) -> None:
 
     def add_middleware(
         self,
-        middleware_class: typing.Type[_MiddlewareClass[P]],
+        middleware_class: type[_MiddlewareClass[P]],
         *args: P.args,
         **kwargs: P.kwargs,
     ) -> None:
@@ -143,7 +143,7 @@ def add_middleware(
 
     def add_exception_handler(
         self,
-        exc_class_or_status_code: int | typing.Type[Exception],
+        exc_class_or_status_code: int | type[Exception],
         handler: ExceptionHandler,
     ) -> None:  # pragma: no cover
         self.exception_handlers[exc_class_or_status_code] = handler
@@ -159,8 +159,8 @@ def add_route(
         self,
         path: str,
         route: typing.Callable[[Request], typing.Awaitable[Response] | Response],
-        methods: typing.Optional[typing.List[str]] = None,
-        name: typing.Optional[str] = None,
+        methods: list[str] | None = None,
+        name: str | None = None,
         include_in_schema: bool = True,
     ) -> None:  # pragma: no cover
         self.router.add_route(
@@ -176,7 +176,7 @@ def add_websocket_route(
         self.router.add_websocket_route(path, route, name=name)
 
     def exception_handler(
-        self, exc_class_or_status_code: int | typing.Type[Exception]
+        self, exc_class_or_status_code: int | type[Exception]
     ) -> typing.Callable:  # type: ignore[type-arg]
         warnings.warn(
             "The `exception_handler` decorator is deprecated, and will be removed in version 1.0.0. "  # noqa: E501

starlette/authentication.py

@@ -75,10 +75,7 @@ async def async_wrapper(*args: _P.args, **kwargs: _P.kwargs) -> typing.Any:
                 if not has_required_scope(request, scopes_list):
                     if redirect is not None:
                         orig_request_qparam = urlencode({"next": str(request.url)})
-                        next_url = "{redirect_path}?{orig_request}".format(
-                            redirect_path=request.url_for(redirect),
-                            orig_request=orig_request_qparam,
-                        )
+                        next_url = f"{request.url_for(redirect)}?{orig_request_qparam}"
                         return RedirectResponse(url=next_url, status_code=303)
                     raise HTTPException(status_code=status_code)
                 return await func(*args, **kwargs)
@@ -95,10 +92,7 @@ def sync_wrapper(*args: _P.args, **kwargs: _P.kwargs) -> typing.Any:
                 if not has_required_scope(request, scopes_list):
                     if redirect is not None:
                         orig_request_qparam = urlencode({"next": str(request.url)})
-                        next_url = "{redirect_path}?{orig_request}".format(
-                            redirect_path=request.url_for(redirect),
-                            orig_request=orig_request_qparam,
-                        )
+                        next_url = f"{request.url_for(redirect)}?{orig_request_qparam}"
                         return RedirectResponse(url=next_url, status_code=303)
                     raise HTTPException(status_code=status_code)
                 return func(*args, **kwargs)

starlette/config.py

@@ -17,7 +17,7 @@ class EnvironError(Exception):
 class Environ(typing.MutableMapping[str, str]):
     def __init__(self, environ: typing.MutableMapping[str, str] = os.environ):
         self._environ = environ
-        self._has_been_read: typing.Set[str] = set()
+        self._has_been_read: set[str] = set()
 
     def __getitem__(self, key: str) -> str:
         self._has_been_read.add(key)
@@ -60,7 +60,7 @@ def __init__(
     ) -> None:
         self.environ = environ
         self.env_prefix = env_prefix
-        self.file_values: typing.Dict[str, str] = {}
+        self.file_values: dict[str, str] = {}
         if env_file is not None:
             if not os.path.isfile(env_file):
                 warnings.warn(f"Config file '{env_file}' not found.")
@@ -118,7 +118,7 @@ def get(
         raise KeyError(f"Config '{key}' is missing, and has no default.")
 
     def _read_file(self, file_name: str | Path) -> dict[str, str]:
-        file_values: typing.Dict[str, str] = {}
+        file_values: dict[str, str] = {}
         with open(file_name) as input_file:
             for line in input_file.readlines():
                 line = line.strip()

starlette/convertors.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import math
 import typing
 import uuid
@@ -74,7 +76,7 @@ def to_string(self, value: uuid.UUID) -> str:
         return str(value)
 
 
-CONVERTOR_TYPES: typing.Dict[str, Convertor[typing.Any]] = {
+CONVERTOR_TYPES: dict[str, Convertor[typing.Any]] = {
     "str": StringConvertor(),
     "path": PathConvertor(),
     "int": IntegerConvertor(),

starlette/datastructures.py

@@ -150,7 +150,7 @@ def replace_query_params(self, **kwargs: typing.Any) -> URL:
         query = urlencode([(str(key), str(value)) for key, value in kwargs.items()])
         return self.replace(query=query)
 
-    def remove_query_params(self, keys: str | typing.Sequence[str]) -> "URL":
+    def remove_query_params(self, keys: str | typing.Sequence[str]) -> URL:
         if isinstance(keys, str):
             keys = [keys]
         params = MultiDict(parse_qsl(self.query, keep_blank_values=True))
@@ -178,7 +178,7 @@ class URLPath(str):
     Used by the routing to return `url_path_for` matches.
     """
 
-    def __new__(cls, path: str, protocol: str = "", host: str = "") -> "URLPath":
+    def __new__(cls, path: str, protocol: str = "", host: str = "") -> URLPath:
         assert protocol in ("http", "websocket", "")
         return str.__new__(cls, path)
 
@@ -251,13 +251,13 @@ def __str__(self) -> str:
 
 
 class ImmutableMultiDict(typing.Mapping[_KeyType, _CovariantValueType]):
-    _dict: typing.Dict[_KeyType, _CovariantValueType]
+    _dict: dict[_KeyType, _CovariantValueType]
 
     def __init__(
         self,
         *args: ImmutableMultiDict[_KeyType, _CovariantValueType]
         | typing.Mapping[_KeyType, _CovariantValueType]
-        | typing.Iterable[typing.Tuple[_KeyType, _CovariantValueType]],
+        | typing.Iterable[tuple[_KeyType, _CovariantValueType]],
         **kwargs: typing.Any,
     ) -> None:
         assert len(args) < 2, "Too many arguments."
@@ -599,7 +599,7 @@ def __setitem__(self, key: str, value: str) -> None:
         set_key = key.lower().encode("latin-1")
         set_value = value.encode("latin-1")
 
-        found_indexes: "typing.List[int]" = []
+        found_indexes: list[int] = []
         for idx, (item_key, item_value) in enumerate(self._list):
             if item_key == set_key:
                 found_indexes.append(idx)
@@ -619,7 +619,7 @@ def __delitem__(self, key: str) -> None:
         """
         del_key = key.lower().encode("latin-1")
 
-        pop_indexes: "typing.List[int]" = []
+        pop_indexes: list[int] = []
         for idx, (item_key, item_value) in enumerate(self._list):
             if item_key == del_key:
                 pop_indexes.append(idx)

starlette/formparsers.py

@@ -91,7 +91,7 @@ async def parse(self) -> FormData:
         field_name = b""
         field_value = b""
 
-        items: list[tuple[str, typing.Union[str, UploadFile]]] = []
+        items: list[tuple[str, str | UploadFile]] = []
 
         # Feed the parser with data from the request.
         async for chunk in self.stream:

starlette/middleware/authentication.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import typing
 
 from starlette.authentication import (
@@ -16,9 +18,8 @@ def __init__(
         self,
         app: ASGIApp,
         backend: AuthenticationBackend,
-        on_error: typing.Optional[
-            typing.Callable[[HTTPConnection, AuthenticationError], Response]
-        ] = None,
+        on_error: typing.Callable[[HTTPConnection, AuthenticationError], Response]
+        | None = None,
     ) -> None:
         self.app = app
         self.backend = backend

starlette/middleware/base.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import typing
 
 import anyio
@@ -92,9 +94,7 @@ async def wrapped_receive(self) -> Message:
 
 
 class BaseHTTPMiddleware:
-    def __init__(
-        self, app: ASGIApp, dispatch: typing.Optional[DispatchFunction] = None
-    ) -> None:
+    def __init__(self, app: ASGIApp, dispatch: DispatchFunction | None = None) -> None:
         self.app = app
         self.dispatch_func = self.dispatch if dispatch is None else dispatch
 
@@ -108,7 +108,7 @@ async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
         response_sent = anyio.Event()
 
         async def call_next(request: Request) -> Response:
-            app_exc: typing.Optional[Exception] = None
+            app_exc: Exception | None = None
             send_stream: ObjectSendStream[typing.MutableMapping[str, typing.Any]]
             recv_stream: ObjectReceiveStream[typing.MutableMapping[str, typing.Any]]
             send_stream, recv_stream = anyio.create_memory_object_stream()
@@ -203,10 +203,10 @@ def __init__(
         self,
         content: ContentStream,
         status_code: int = 200,
-        headers: typing.Optional[typing.Mapping[str, str]] = None,
-        media_type: typing.Optional[str] = None,
-        background: typing.Optional[BackgroundTask] = None,
-        info: typing.Optional[typing.Mapping[str, typing.Any]] = None,
+        headers: typing.Mapping[str, str] | None = None,
+        media_type: str | None = None,
+        background: BackgroundTask | None = None,
+        info: typing.Mapping[str, typing.Any] | None = None,
     ) -> None:
         self._info = info
         super().__init__(content, status_code, headers, media_type, background)

starlette/middleware/cors.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import functools
 import re
 import typing
@@ -18,7 +20,7 @@ def __init__(
         allow_methods: typing.Sequence[str] = ("GET",),
         allow_headers: typing.Sequence[str] = (),
         allow_credentials: bool = False,
-        allow_origin_regex: typing.Optional[str] = None,
+        allow_origin_regex: str | None = None,
         expose_headers: typing.Sequence[str] = (),
         max_age: int = 600,
     ) -> None:

starlette/middleware/errors.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import html
 import inspect
 import traceback
@@ -137,9 +139,7 @@ class ServerErrorMiddleware:
     def __init__(
         self,
         app: ASGIApp,
-        handler: typing.Optional[
-            typing.Callable[[Request, Exception], typing.Any]
-        ] = None,
+        handler: typing.Callable[[Request, Exception], typing.Any] | None = None,
         debug: bool = False,
     ) -> None:
         self.app = app

starlette/middleware/exceptions.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import typing
 
 from starlette._exception_handler import (
@@ -16,9 +18,10 @@ class ExceptionMiddleware:
     def __init__(
         self,
         app: ASGIApp,
-        handlers: typing.Optional[
-            typing.Mapping[typing.Any, typing.Callable[[Request, Exception], Response]]
-        ] = None,
+        handlers: typing.Mapping[
+            typing.Any, typing.Callable[[Request, Exception], Response]
+        ]
+        | None = None,
         debug: bool = False,
     ) -> None:
         self.app = app
@@ -34,7 +37,7 @@ def __init__(
 
     def add_exception_handler(
         self,
-        exc_class_or_status_code: typing.Union[int, typing.Type[Exception]],
+        exc_class_or_status_code: int | type[Exception],
         handler: typing.Callable[[Request, Exception], Response],
     ) -> None:
         if isinstance(exc_class_or_status_code, int):
@@ -53,7 +56,7 @@ async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
             self._status_handlers,
         )
 
-        conn: typing.Union[Request, WebSocket]
+        conn: Request | WebSocket
         if scope["type"] == "http":
             conn = Request(scope, receive, send)
         else:

starlette/middleware/sessions.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import json
 import typing
 from base64 import b64decode, b64encode
@@ -14,13 +16,13 @@ class SessionMiddleware:
     def __init__(
         self,
         app: ASGIApp,
-        secret_key: typing.Union[str, Secret],
+        secret_key: str | Secret,
         session_cookie: str = "session",
-        max_age: typing.Optional[int] = 14 * 24 * 60 * 60,  # 14 days, in seconds
+        max_age: int | None = 14 * 24 * 60 * 60,  # 14 days, in seconds
         path: str = "/",
         same_site: typing.Literal["lax", "strict", "none"] = "lax",
         https_only: bool = False,
-        domain: typing.Optional[str] = None,
+        domain: str | None = None,
     ) -> None:
         self.app = app
         self.signer = itsdangerous.TimestampSigner(str(secret_key))

starlette/middleware/trustedhost.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import typing
 
 from starlette.datastructures import URL, Headers
@@ -11,7 +13,7 @@ class TrustedHostMiddleware:
     def __init__(
         self,
         app: ASGIApp,
-        allowed_hosts: typing.Optional[typing.Sequence[str]] = None,
+        allowed_hosts: typing.Sequence[str] | None = None,
         www_redirect: bool = True,
     ) -> None:
         if allowed_hosts is None: