add __future__ annotations

CHANGES.rst

@@ -46,6 +46,7 @@ Unreleased
     :issue:`5051`
 -   The ``routes`` command shows each rule's ``subdomain`` or ``host`` when domain
     matching is in use. :issue:`5004`
+-   Use postponed evaluation of annotations. :pr:`5071`
 
 
 Version 2.2.4

src/flask/blueprints.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import os
 import typing as t
 from collections import defaultdict
@@ -38,8 +40,8 @@ class BlueprintSetupState:
 
     def __init__(
         self,
-        blueprint: "Blueprint",
-        app: "Flask",
+        blueprint: Blueprint,
+        app: Flask,
         options: t.Any,
         first_registration: bool,
     ) -> None:
@@ -85,8 +87,8 @@ def __init__(
     def add_url_rule(
         self,
         rule: str,
-        endpoint: t.Optional[str] = None,
-        view_func: t.Optional[t.Callable] = None,
+        endpoint: str | None = None,
+        view_func: t.Callable | None = None,
         **options: t.Any,
     ) -> None:
         """A helper method to register a rule (and optionally a view function)
@@ -173,14 +175,14 @@ def __init__(
         self,
         name: str,
         import_name: str,
-        static_folder: t.Optional[t.Union[str, os.PathLike]] = None,
-        static_url_path: t.Optional[str] = None,
-        template_folder: t.Optional[t.Union[str, os.PathLike]] = None,
-        url_prefix: t.Optional[str] = None,
-        subdomain: t.Optional[str] = None,
-        url_defaults: t.Optional[dict] = None,
-        root_path: t.Optional[str] = None,
-        cli_group: t.Optional[str] = _sentinel,  # type: ignore
+        static_folder: str | os.PathLike | None = None,
+        static_url_path: str | None = None,
+        template_folder: str | os.PathLike | None = None,
+        url_prefix: str | None = None,
+        subdomain: str | None = None,
+        url_defaults: dict | None = None,
+        root_path: str | None = None,
+        cli_group: str | None = _sentinel,  # type: ignore
     ):
         super().__init__(
             import_name=import_name,
@@ -199,14 +201,14 @@ def __init__(
         self.name = name
         self.url_prefix = url_prefix
         self.subdomain = subdomain
-        self.deferred_functions: t.List[DeferredSetupFunction] = []
+        self.deferred_functions: list[DeferredSetupFunction] = []
 
         if url_defaults is None:
             url_defaults = {}
 
         self.url_values_defaults = url_defaults
         self.cli_group = cli_group
-        self._blueprints: t.List[t.Tuple["Blueprint", dict]] = []
+        self._blueprints: list[tuple[Blueprint, dict]] = []
 
     def _check_setup_finished(self, f_name: str) -> None:
         if self._got_registered_once:
@@ -242,7 +244,7 @@ def wrapper(state: BlueprintSetupState) -> None:
         self.record(update_wrapper(wrapper, func))
 
     def make_setup_state(
-        self, app: "Flask", options: dict, first_registration: bool = False
+        self, app: Flask, options: dict, first_registration: bool = False
     ) -> BlueprintSetupState:
         """Creates an instance of :meth:`~flask.blueprints.BlueprintSetupState`
         object that is later passed to the register callback functions.
@@ -251,7 +253,7 @@ def make_setup_state(
         return BlueprintSetupState(self, app, options, first_registration)
 
     @setupmethod
-    def register_blueprint(self, blueprint: "Blueprint", **options: t.Any) -> None:
+    def register_blueprint(self, blueprint: Blueprint, **options: t.Any) -> None:
         """Register a :class:`~flask.Blueprint` on this blueprint. Keyword
         arguments passed to this method will override the defaults set
         on the blueprint.
@@ -268,7 +270,7 @@ def register_blueprint(self, blueprint: "Blueprint", **options: t.Any) -> None:
             raise ValueError("Cannot register a blueprint on itself")
         self._blueprints.append((blueprint, options))
 
-    def register(self, app: "Flask", options: dict) -> None:
+    def register(self, app: Flask, options: dict) -> None:
         """Called by :meth:`Flask.register_blueprint` to register all
         views and callbacks registered on the blueprint with the
         application. Creates a :class:`.BlueprintSetupState` and calls
@@ -408,9 +410,9 @@ def extend(bp_dict, parent_dict):
     def add_url_rule(
         self,
         rule: str,
-        endpoint: t.Optional[str] = None,
-        view_func: t.Optional[ft.RouteCallable] = None,
-        provide_automatic_options: t.Optional[bool] = None,
+        endpoint: str | None = None,
+        view_func: ft.RouteCallable | None = None,
+        provide_automatic_options: bool | None = None,
         **options: t.Any,
     ) -> None:
         """Register a URL rule with the blueprint. See :meth:`.Flask.add_url_rule` for
@@ -437,7 +439,7 @@ def add_url_rule(
 
     @setupmethod
     def app_template_filter(
-        self, name: t.Optional[str] = None
+        self, name: str | None = None
     ) -> t.Callable[[T_template_filter], T_template_filter]:
         """Register a template filter, available in any template rendered by the
         application. Equivalent to :meth:`.Flask.template_filter`.
@@ -454,7 +456,7 @@ def decorator(f: T_template_filter) -> T_template_filter:
 
     @setupmethod
     def add_app_template_filter(
-        self, f: ft.TemplateFilterCallable, name: t.Optional[str] = None
+        self, f: ft.TemplateFilterCallable, name: str | None = None
     ) -> None:
         """Register a template filter, available in any template rendered by the
         application. Works like the :meth:`app_template_filter` decorator. Equivalent to
@@ -471,7 +473,7 @@ def register_template(state: BlueprintSetupState) -> None:
 
     @setupmethod
     def app_template_test(
-        self, name: t.Optional[str] = None
+        self, name: str | None = None
     ) -> t.Callable[[T_template_test], T_template_test]:
         """Register a template test, available in any template rendered by the
         application. Equivalent to :meth:`.Flask.template_test`.
@@ -490,7 +492,7 @@ def decorator(f: T_template_test) -> T_template_test:
 
     @setupmethod
     def add_app_template_test(
-        self, f: ft.TemplateTestCallable, name: t.Optional[str] = None
+        self, f: ft.TemplateTestCallable, name: str | None = None
     ) -> None:
         """Register a template test, available in any template rendered by the
         application. Works like the :meth:`app_template_test` decorator. Equivalent to
@@ -509,7 +511,7 @@ def register_template(state: BlueprintSetupState) -> None:
 
     @setupmethod
     def app_template_global(
-        self, name: t.Optional[str] = None
+        self, name: str | None = None
     ) -> t.Callable[[T_template_global], T_template_global]:
         """Register a template global, available in any template rendered by the
         application. Equivalent to :meth:`.Flask.template_global`.
@@ -528,7 +530,7 @@ def decorator(f: T_template_global) -> T_template_global:
 
     @setupmethod
     def add_app_template_global(
-        self, f: ft.TemplateGlobalCallable, name: t.Optional[str] = None
+        self, f: ft.TemplateGlobalCallable, name: str | None = None
     ) -> None:
         """Register a template global, available in any template rendered by the
         application. Works like the :meth:`app_template_global` decorator. Equivalent to
@@ -589,7 +591,7 @@ def app_context_processor(
 
     @setupmethod
     def app_errorhandler(
-        self, code: t.Union[t.Type[Exception], int]
+        self, code: type[Exception] | int
     ) -> t.Callable[[T_error_handler], T_error_handler]:
         """Like :meth:`errorhandler`, but for every request, not only those handled by
         the blueprint. Equivalent to :meth:`.Flask.errorhandler`.

src/flask/cli.py

@@ -285,7 +285,7 @@ def __init__(
         self.create_app = create_app
         #: A dictionary with arbitrary data that can be associated with
         #: this script info.
-        self.data: t.Dict[t.Any, t.Any] = {}
+        self.data: dict[t.Any, t.Any] = {}
         self.set_debug_flag = set_debug_flag
         self._loaded_app: Flask | None = None
 

src/flask/config.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import errno
 import json
 import os
@@ -10,7 +12,7 @@
 class ConfigAttribute:
     """Makes an attribute forward to the config"""
 
-    def __init__(self, name: str, get_converter: t.Optional[t.Callable] = None) -> None:
+    def __init__(self, name: str, get_converter: t.Callable | None = None) -> None:
         self.__name__ = name
         self.get_converter = get_converter
 
@@ -70,7 +72,7 @@ class Config(dict):
     :param defaults: an optional dictionary of default values
     """
 
-    def __init__(self, root_path: str, defaults: t.Optional[dict] = None) -> None:
+    def __init__(self, root_path: str, defaults: dict | None = None) -> None:
         super().__init__(defaults or {})
         self.root_path = root_path
 
@@ -191,7 +193,7 @@ def from_pyfile(self, filename: str, silent: bool = False) -> bool:
         self.from_object(d)
         return True
 
-    def from_object(self, obj: t.Union[object, str]) -> None:
+    def from_object(self, obj: object | str) -> None:
         """Updates the values from the given object.  An object can be of one
         of the following two types:
 
@@ -278,7 +280,7 @@ def from_file(
         return self.from_mapping(obj)
 
     def from_mapping(
-        self, mapping: t.Optional[t.Mapping[str, t.Any]] = None, **kwargs: t.Any
+        self, mapping: t.Mapping[str, t.Any] | None = None, **kwargs: t.Any
     ) -> bool:
         """Updates the config like :meth:`update` ignoring items with
         non-upper keys.
@@ -287,7 +289,7 @@ def from_mapping(
 
         .. versionadded:: 0.11
         """
-        mappings: t.Dict[str, t.Any] = {}
+        mappings: dict[str, t.Any] = {}
         if mapping is not None:
             mappings.update(mapping)
         mappings.update(kwargs)
@@ -298,7 +300,7 @@ def from_mapping(
 
     def get_namespace(
         self, namespace: str, lowercase: bool = True, trim_namespace: bool = True
-    ) -> t.Dict[str, t.Any]:
+    ) -> dict[str, t.Any]:
         """Returns a dictionary containing a subset of configuration options
         that match the specified namespace/prefix. Example usage::
 

src/flask/ctx.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import contextvars
 import sys
 import typing as t
@@ -60,7 +62,7 @@ def __delattr__(self, name: str) -> None:
         except KeyError:
             raise AttributeError(name) from None
 
-    def get(self, name: str, default: t.Optional[t.Any] = None) -> t.Any:
+    def get(self, name: str, default: t.Any | None = None) -> t.Any:
         """Get an attribute by name, or a default value. Like
         :meth:`dict.get`.
 
@@ -233,18 +235,18 @@ class AppContext:
     running CLI commands.
     """
 
-    def __init__(self, app: "Flask") -> None:
+    def __init__(self, app: Flask) -> None:
         self.app = app
         self.url_adapter = app.create_url_adapter(None)
         self.g: _AppCtxGlobals = app.app_ctx_globals_class()
-        self._cv_tokens: t.List[contextvars.Token] = []
+        self._cv_tokens: list[contextvars.Token] = []
 
     def push(self) -> None:
         """Binds the app context to the current context."""
         self._cv_tokens.append(_cv_app.set(self))
         appcontext_pushed.send(self.app, _async_wrapper=self.app.ensure_sync)
 
-    def pop(self, exc: t.Optional[BaseException] = _sentinel) -> None:  # type: ignore
+    def pop(self, exc: BaseException | None = _sentinel) -> None:  # type: ignore
         """Pops the app context."""
         try:
             if len(self._cv_tokens) == 1:
@@ -262,15 +264,15 @@ def pop(self, exc: t.Optional[BaseException] = _sentinel) -> None:  # type: igno
 
         appcontext_popped.send(self.app, _async_wrapper=self.app.ensure_sync)
 
-    def __enter__(self) -> "AppContext":
+    def __enter__(self) -> AppContext:
         self.push()
         return self
 
     def __exit__(
         self,
-        exc_type: t.Optional[type],
-        exc_value: t.Optional[BaseException],
-        tb: t.Optional[TracebackType],
+        exc_type: type | None,
+        exc_value: BaseException | None,
+        tb: TracebackType | None,
     ) -> None:
         self.pop(exc_value)
 
@@ -299,10 +301,10 @@ class RequestContext:
 
     def __init__(
         self,
-        app: "Flask",
+        app: Flask,
         environ: dict,
-        request: t.Optional["Request"] = None,
-        session: t.Optional["SessionMixin"] = None,
+        request: Request | None = None,
+        session: SessionMixin | None = None,
     ) -> None:
         self.app = app
         if request is None:
@@ -314,16 +316,16 @@ def __init__(
             self.url_adapter = app.create_url_adapter(self.request)
         except HTTPException as e:
             self.request.routing_exception = e
-        self.flashes: t.Optional[t.List[t.Tuple[str, str]]] = None
-        self.session: t.Optional["SessionMixin"] = session
+        self.flashes: list[tuple[str, str]] | None = None
+        self.session: SessionMixin | None = session
         # Functions that should be executed after the request on the response
         # object.  These will be called before the regular "after_request"
         # functions.
-        self._after_request_functions: t.List[ft.AfterRequestCallable] = []
+        self._after_request_functions: list[ft.AfterRequestCallable] = []
 
-        self._cv_tokens: t.List[t.Tuple[contextvars.Token, t.Optional[AppContext]]] = []
+        self._cv_tokens: list[tuple[contextvars.Token, AppContext | None]] = []
 
-    def copy(self) -> "RequestContext":
+    def copy(self) -> RequestContext:
         """Creates a copy of this request context with the same request object.
         This can be used to move a request context to a different greenlet.
         Because the actual request object is the same this cannot be used to
@@ -382,7 +384,7 @@ def push(self) -> None:
         if self.url_adapter is not None:
             self.match_request()
 
-    def pop(self, exc: t.Optional[BaseException] = _sentinel) -> None:  # type: ignore
+    def pop(self, exc: BaseException | None = _sentinel) -> None:  # type: ignore
         """Pops the request context and unbinds it by doing that.  This will
         also trigger the execution of functions registered by the
         :meth:`~flask.Flask.teardown_request` decorator.
@@ -419,15 +421,15 @@ def pop(self, exc: t.Optional[BaseException] = _sentinel) -> None:  # type: igno
                     f"Popped wrong request context. ({ctx!r} instead of {self!r})"
                 )
 
-    def __enter__(self) -> "RequestContext":
+    def __enter__(self) -> RequestContext:
         self.push()
         return self
 
     def __exit__(
         self,
-        exc_type: t.Optional[type],
-        exc_value: t.Optional[BaseException],
-        tb: t.Optional[TracebackType],
+        exc_type: type | None,
+        exc_value: BaseException | None,
+        tb: TracebackType | None,
     ) -> None:
         self.pop(exc_value)
 

src/flask/debughelpers.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import typing as t
 
 from .app import Flask