Update typing

CHANGES.rst

@@ -8,6 +8,11 @@ Unreleased
 -   Re-add the ``filename`` parameter in ``send_from_directory``. The
     ``filename`` parameter has been renamed to ``path``, the old name
     is deprecated. :pr:`4019`
+-   Mark top-level names as exported so type checking understands
+    imports in user projects. :issue:`4024`
+-   Fix type annotation for ``g`` and inform mypy that it is a namespace
+    object that has arbitrary attributes. :issue:`4020`
+-   Fix some types that weren't available in Python 3.6.0. :issue:`4040`
 
 
 Version 2.0.0

src/flask/__init__.py

@@ -1,46 +1,46 @@
 from markupsafe import escape
 from markupsafe import Markup
-from werkzeug.exceptions import abort
-from werkzeug.utils import redirect
+from werkzeug.exceptions import abort as abort
+from werkzeug.utils import redirect as redirect
 
-from . import json
-from .app import Flask
-from .app import Request
-from .app import Response
-from .blueprints import Blueprint
-from .config import Config
-from .ctx import after_this_request
-from .ctx import copy_current_request_context
-from .ctx import has_app_context
-from .ctx import has_request_context
-from .globals import _app_ctx_stack
-from .globals import _request_ctx_stack
-from .globals import current_app
-from .globals import g
-from .globals import request
-from .globals import session
-from .helpers import flash
-from .helpers import get_flashed_messages
-from .helpers import get_template_attribute
-from .helpers import make_response
-from .helpers import safe_join
-from .helpers import send_file
-from .helpers import send_from_directory
-from .helpers import stream_with_context
-from .helpers import url_for
-from .json import jsonify
-from .signals import appcontext_popped
-from .signals import appcontext_pushed
-from .signals import appcontext_tearing_down
-from .signals import before_render_template
-from .signals import got_request_exception
-from .signals import message_flashed
-from .signals import request_finished
-from .signals import request_started
-from .signals import request_tearing_down
-from .signals import signals_available
-from .signals import template_rendered
-from .templating import render_template
-from .templating import render_template_string
+from . import json as json
+from .app import Flask as Flask
+from .app import Request as Request
+from .app import Response as Response
+from .blueprints import Blueprint as Blueprint
+from .config import Config as Config
+from .ctx import after_this_request as after_this_request
+from .ctx import copy_current_request_context as copy_current_request_context
+from .ctx import has_app_context as has_app_context
+from .ctx import has_request_context as has_request_context
+from .globals import _app_ctx_stack as _app_ctx_stack
+from .globals import _request_ctx_stack as _request_ctx_stack
+from .globals import current_app as current_app
+from .globals import g as g
+from .globals import request as request
+from .globals import session as session
+from .helpers import flash as flash
+from .helpers import get_flashed_messages as get_flashed_messages
+from .helpers import get_template_attribute as get_template_attribute
+from .helpers import make_response as make_response
+from .helpers import safe_join as safe_join
+from .helpers import send_file as send_file
+from .helpers import send_from_directory as send_from_directory
+from .helpers import stream_with_context as stream_with_context
+from .helpers import url_for as url_for
+from .json import jsonify as jsonify
+from .signals import appcontext_popped as appcontext_popped
+from .signals import appcontext_pushed as appcontext_pushed
+from .signals import appcontext_tearing_down as appcontext_tearing_down
+from .signals import before_render_template as before_render_template
+from .signals import got_request_exception as got_request_exception
+from .signals import message_flashed as message_flashed
+from .signals import request_finished as request_finished
+from .signals import request_started as request_started
+from .signals import request_tearing_down as request_tearing_down
+from .signals import signals_available as signals_available
+from .signals import template_rendered as template_rendered
+from .templating import render_template as render_template
+from .templating import render_template_string as render_template_string
 
 __version__ = "2.0.1.dev0"

src/flask/app.py

@@ -72,6 +72,7 @@
 from .wrappers import Response
 
 if t.TYPE_CHECKING:
+    import typing_extensions as te
     from .blueprints import Blueprint
     from .testing import FlaskClient
     from .testing import FlaskCliRunner
@@ -1441,7 +1442,7 @@ def log_exception(
             f"Exception on {request.path} [{request.method}]", exc_info=exc_info
         )
 
-    def raise_routing_exception(self, request: Request) -> t.NoReturn:
+    def raise_routing_exception(self, request: Request) -> "te.NoReturn":
         """Exceptions that are recording during routing are reraised with
         this method.  During debug we are not reraising redirect requests
         for non ``GET``, ``HEAD``, or ``OPTIONS`` requests and we're raising

src/flask/ctx.py

@@ -41,6 +41,24 @@ class _AppCtxGlobals:
         .. versionadded:: 0.10
     """
 
+    # Define attr methods to let mypy know this is a namespace object
+    # that has arbitrary attributes.
+
+    def __getattr__(self, name: str) -> t.Any:
+        try:
+            return self.__dict__[name]
+        except KeyError:
+            raise AttributeError(name) from None
+
+    def __setattr__(self, name: str, value: t.Any) -> None:
+        self.__dict__[name] = value
+
+    def __delattr__(self, name: str) -> None:
+        try:
+            del self.__dict__[name]
+        except KeyError:
+            raise AttributeError(name) from None
+
     def get(self, name: str, default: t.Optional[t.Any] = None) -> t.Any:
         """Get an attribute by name, or a default value. Like
         :meth:`dict.get`.
@@ -78,10 +96,10 @@ def setdefault(self, name: str, default: t.Any = None) -> t.Any:
         """
         return self.__dict__.setdefault(name, default)
 
-    def __contains__(self, item: t.Any) -> bool:
+    def __contains__(self, item: str) -> bool:
         return item in self.__dict__
 
-    def __iter__(self) -> t.Iterator:
+    def __iter__(self) -> t.Iterator[str]:
         return iter(self.__dict__)
 
     def __repr__(self) -> str:

src/flask/globals.py

@@ -6,7 +6,7 @@
 
 if t.TYPE_CHECKING:
     from .app import Flask
-    from .ctx import AppContext
+    from .ctx import _AppCtxGlobals
     from .sessions import SessionMixin
     from .wrappers import Request
 
@@ -53,5 +53,7 @@ def _find_app():
 _app_ctx_stack = LocalStack()
 current_app: "Flask" = LocalProxy(_find_app)  # type: ignore
 request: "Request" = LocalProxy(partial(_lookup_req_object, "request"))  # type: ignore
-session: "SessionMixin" = LocalProxy(partial(_lookup_req_object, "session"))  # type: ignore # noqa: B950
-g: "AppContext" = LocalProxy(partial(_lookup_app_object, "g"))  # type: ignore
+session: "SessionMixin" = LocalProxy(  # type: ignore
+    partial(_lookup_req_object, "session")
+)
+g: "_AppCtxGlobals" = LocalProxy(partial(_lookup_app_object, "g"))  # type: ignore

src/flask/sessions.py

@@ -12,6 +12,7 @@
 from .json.tag import TaggedJSONSerializer
 
 if t.TYPE_CHECKING:
+    import typing_extensions as te
     from .app import Flask
     from .wrappers import Request, Response
 
@@ -92,7 +93,7 @@ class NullSession(SecureCookieSession):
     but fail on setting.
     """
 
-    def _fail(self, *args: t.Any, **kwargs: t.Any) -> t.NoReturn:
+    def _fail(self, *args: t.Any, **kwargs: t.Any) -> "te.NoReturn":
         raise RuntimeError(
             "The session is unavailable because no secret "
             "key was set.  Set the secret_key on the "

src/flask/wrappers.py

@@ -8,6 +8,7 @@
 from .globals import current_app
 
 if t.TYPE_CHECKING:
+    import typing_extensions as te
     from werkzeug.routing import Rule
 
 
@@ -91,7 +92,7 @@ def _load_form_data(self) -> None:
 
             attach_enctype_error_multidict(self)
 
-    def on_json_loading_failed(self, e: Exception) -> t.NoReturn:
+    def on_json_loading_failed(self, e: Exception) -> "te.NoReturn":
         if current_app and current_app.debug:
             raise BadRequest(f"Failed to decode JSON object: {e}")