[WIP] Migrate to AnyIO

.github/workflows/tests.yaml

@@ -19,7 +19,6 @@ jobs:
           - {python: '3.12'}
           - {python: '3.11'}
           - {python: '3.10'}
-          - {python: '3.9'}
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
       - uses: astral-sh/setup-uv@f0ec1fc3b38f5e7cd731bb6ce540c5af426746bb # v6.1.0

docs/tutorials/installation.rst

@@ -16,7 +16,7 @@ Dependencies
 Quart dependends on the following packages, which will automatically
 be installed with Quart:
 
-- aiofiles, to load files in an asyncio compatible manner,
+- AnyIO, to handle I/O operations,
 - blinker, to manage signals,
 - click, to manage command line arguments
 - hypercorn, an ASGI server for development,

examples/api/tests/test_api.py

@@ -1,14 +1,17 @@
+import pytest
 from api import app
 from api import TodoIn
 
 
+@pytest.mark.anyio
 async def test_echo() -> None:
     test_client = app.test_client()
     response = await test_client.post("/echo", json={"a": "b"})
     data = await response.get_json()
     assert data == {"extra": True, "input": {"a": "b"}}
 
 
+@pytest.mark.anyio
 async def test_create_todo() -> None:
     test_client = app.test_client()
     response = await test_client.post("/todos/", json=TodoIn(task="Abc", due=None))

examples/blog/tests/test_blog.py

@@ -1,6 +1,8 @@
+import pytest
 from blog import app
 
 
+@pytest.mark.anyio
 async def test_create_post():
     test_client = app.test_client()
     response = await test_client.post(

examples/chat/tests/test_chat.py

@@ -1,5 +1,6 @@
 import asyncio
 
+import pytest
 from chat import app
 
 from quart.testing.connections import (
@@ -11,6 +12,7 @@ async def _receive(test_websocket: _TestWebsocketConnection) -> str:
     return await test_websocket.receive()
 
 
+@pytest.mark.anyio
 async def test_websocket() -> None:
     test_client = app.test_client()
     async with test_client.websocket("/ws") as test_websocket:

examples/video/tests/test_video.py

@@ -1,6 +1,8 @@
+import pytest
 from video import app
 
 
+@pytest.mark.anyio
 async def test_auto_video() -> None:
     test_client = app.test_client()
     response = await test_client.get("/video.mp4")

pyproject.toml

@@ -18,9 +18,9 @@ classifiers = [
     "Topic :: Software Development :: Libraries :: Application Frameworks",
     "Typing :: Typed",
 ]
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 dependencies = [
-    "aiofiles",
+    "anyio>=4.14.0,<5",
     "blinker>=1.6",
     "click>=8.0",
     "flask>=3.0",
@@ -48,6 +48,7 @@ quart = "quart.cli:main"
 
 [dependency-groups]
 dev = [
+    "trio==0.33.0",
     "ruff",
     "tox",
     "tox-uv",
@@ -70,7 +71,6 @@ pre-commit = [
 tests = [
     "hypothesis",
     "pytest",
-    "pytest-asyncio",
     "pytest-cov",
     "pytest-sugar",
     "python-dotenv",
@@ -79,7 +79,6 @@ typing = [
     "mypy",
     "pyright",
     "pytest",
-    "types-aiofiles",
 ]
 
 [build-system]
@@ -94,8 +93,6 @@ default-groups = ["dev", "pre-commit", "tests", "typing"]
 
 [tool.pytest.ini_options]
 addopts = "--no-cov-on-fail --showlocals --strict-markers"
-asyncio_default_fixture_loop_scope = "session"
-asyncio_mode = "auto"
 testpaths = ["tests"]
 filterwarnings = [
     "error",
@@ -116,7 +113,7 @@ exclude_also = [
 ]
 
 [tool.mypy]
-python_version = "3.9"
+python_version = "3.10"
 files = ["src", "tests"]
 show_error_codes = true
 pretty = true
@@ -131,7 +128,7 @@ strict_optional = false
 warn_return_any = false
 
 [tool.pyright]
-pythonVersion = "3.9"
+pythonVersion = "3.10"
 include = ["src", "tests"]
 typeCheckingMode = "basic"
 
@@ -162,7 +159,7 @@ order-by-type = false
 
 [tool.tox]
 env_list = [
-    "py3.13", "py3.12", "py3.11", "py3.10", "py3.9",
+    "py3.13", "py3.12", "py3.11", "py3.10",
     "style",
     "typing",
     "docs",

src/quart/app.py

@@ -8,6 +8,7 @@
 from collections import defaultdict
 from collections.abc import AsyncGenerator
 from collections.abc import Awaitable
+from collections.abc import Callable
 from collections.abc import Coroutine
 from datetime import timedelta
 from inspect import isasyncgen
@@ -16,16 +17,17 @@
 from types import TracebackType
 from typing import Any
 from typing import AnyStr
-from typing import Callable
 from typing import cast
 from typing import NoReturn
 from typing import Optional
 from typing import overload
+from typing import ParamSpec
 from typing import TypeVar
 from urllib.parse import quote
 
-from aiofiles import open as async_open
-from aiofiles.base import AiofilesContextManager
+import anyio
+from anyio import AsyncFile
+from anyio import open_file as async_open
 from flask.sansio.app import App
 from flask.sansio.scaffold import setupmethod
 from hypercorn.asyncio import serve
@@ -125,11 +127,6 @@
 from .wrappers import Response
 from .wrappers import Websocket
 
-if sys.version_info >= (3, 10):
-    from typing import ParamSpec
-else:
-    from typing_extensions import ParamSpec
-
 # Python 3.14 deprecated asyncio.iscoroutinefunction, but suggested
 # inspect.iscoroutinefunction does not work correctly in some Python
 # versions before 3.12.
@@ -225,9 +222,9 @@ class Quart(App):
     asgi_lifespan_class = ASGILifespan
     asgi_websocket_class = ASGIWebsocketConnection
     config_class = Config
-    event_class = asyncio.Event
+    event_class = anyio.Event
     jinja_environment = Environment  # type: ignore[assignment]
-    lock_class = asyncio.Lock
+    lock_class = anyio.Lock
     request_class = Request
     response_class = Response
     session_interface = SecureCookieSessionInterface()
@@ -332,7 +329,8 @@ def __init__(
         self.after_websocket_funcs: dict[
             AppOrBlueprintKey, list[AfterWebsocketCallable]
         ] = defaultdict(list)
-        self.background_tasks: set[asyncio.Task] = set()
+        self.background_tasks: set[anyio.TaskHandle] = set()
+        self.before_serving_funcs: list[Callable[[], Awaitable[None]]] = []
         self.before_serving_funcs: list[Callable[[], Awaitable[None]]] = []
         self.before_websocket_funcs: dict[
             AppOrBlueprintKey, list[BeforeWebsocketCallable]
@@ -392,7 +390,7 @@ async def open_resource(
         self,
         path: FilePath,
         mode: str = "rb",
-    ) -> AiofilesContextManager:
+    ) -> AsyncFile:
         """Open a file for reading.
 
         Use as
@@ -409,7 +407,7 @@ async def open_resource(
 
     async def open_instance_resource(
         self, path: FilePath, mode: str = "rb"
-    ) -> AiofilesContextManager:
+    ) -> AsyncFile:
         """Open a file for reading.
 
         Use as

src/quart/asgi.py

@@ -5,7 +5,6 @@
 from functools import partial
 from typing import AnyStr
 from typing import cast
-from typing import Optional
 from typing import TYPE_CHECKING
 from urllib.parse import urlparse
 
@@ -110,7 +109,7 @@ async def handle_request(self, request: Request, send: ASGISendCallable) -> None
             response = await _handle_exception(self.app, error)
 
         if isinstance(response, Response) and response.timeout != Ellipsis:
-            timeout = cast(Optional[float], response.timeout)
+            timeout = cast(float | None, response.timeout)
         else:
             timeout = self.app.config["RESPONSE_TIMEOUT"]
         try:

src/quart/blueprints.py

@@ -5,8 +5,8 @@
 from collections import defaultdict
 from datetime import timedelta
 
-from aiofiles import open as async_open
-from aiofiles.base import AiofilesContextManager
+from anyio import AsyncFile
+from anyio import open_file as async_open
 from flask.sansio.app import App
 from flask.sansio.blueprints import Blueprint as SansioBlueprint  # noqa
 from flask.sansio.blueprints import BlueprintSetupState as BlueprintSetupState  # noqa
@@ -96,7 +96,7 @@ async def open_resource(
         self,
         path: FilePath,
         mode: str = "rb",
-    ) -> AiofilesContextManager:
+    ) -> AsyncFile:
         """Open a file for reading.
 
         Use as

src/quart/cli.py

@@ -10,11 +10,12 @@
 import re
 import sys
 import traceback
+from collections.abc import Callable
 from importlib import import_module
+from importlib.metadata import entry_points
 from operator import attrgetter
 from types import ModuleType
 from typing import Any
-from typing import Callable
 from typing import TYPE_CHECKING
 
 import click
@@ -488,15 +489,6 @@ def __init__(
     def _load_plugin_commands(self) -> None:
         if self._loaded_plugin_commands:
             return
-
-        if sys.version_info >= (3, 10):
-            from importlib.metadata import entry_points
-        else:
-            # Use a backport on Python < 3.10. We technically have
-            # importlib.metadata on 3.8+, but the API changed in 3.10,
-            # so use the backport for consistency.
-            from importlib_metadata import entry_points
-
         for point in entry_points(group="quart.commands"):
             self.add_command(point.load(), point.name)
 

src/quart/config.py

@@ -1,8 +1,8 @@
 from __future__ import annotations
 
 import json
+from collections.abc import Callable
 from typing import Any
-from typing import Callable
 
 from flask.config import Config as FlaskConfig  # noqa: F401
 from flask.config import ConfigAttribute as ConfigAttribute  # noqa: F401

src/quart/ctx.py

@@ -1,11 +1,11 @@
 from __future__ import annotations
 
 import sys
+from collections.abc import Callable
 from contextvars import Token
 from functools import wraps
 from types import TracebackType
 from typing import Any
-from typing import Callable
 from typing import cast
 from typing import TYPE_CHECKING
 

src/quart/datastructures.py

@@ -1,10 +1,10 @@
 from __future__ import annotations
 
 from os import PathLike
-from pathlib import Path
 from typing import IO
 
-from aiofiles import open as async_open
+from anyio import open_file as async_open
+from anyio import Path
 from werkzeug.datastructures import FileStorage as WerkzeugFileStorage
 from werkzeug.datastructures import Headers
 
@@ -30,7 +30,7 @@ async def save(self, destination: PathLike, buffer_size: int = 16384) -> None:
             destination: A filename (str) or file object to write to.
             buffer_size: Buffer size to keep in memory.
         """
-        async with async_open(destination, "wb") as file_:
+        async with await async_open(destination, "wb") as file_:
             data = self.stream.read(buffer_size)
             while data != b"":
                 await file_.write(data)
@@ -39,7 +39,7 @@ async def save(self, destination: PathLike, buffer_size: int = 16384) -> None:
     async def load(self, source: PathLike, buffer_size: int = 16384) -> None:
         path = Path(source)
         self.filename = path.name
-        async with async_open(path, "rb") as file_:
+        async with await async_open(path, "rb") as file_:
             data = await file_.read(buffer_size)
             while data != b"":
                 self.stream.write(data)

src/quart/formparser.py

@@ -1,12 +1,11 @@
 from __future__ import annotations
 
 from collections.abc import Awaitable
+from collections.abc import Callable
 from typing import Any
-from typing import Callable
 from typing import cast
 from typing import IO
 from typing import NoReturn
-from typing import Optional
 from typing import TYPE_CHECKING
 from urllib.parse import parse_qsl
 
@@ -28,12 +27,12 @@
     from .wrappers.request import Body
 
 StreamFactory = Callable[
-    [Optional[int], Optional[str], Optional[str], Optional[int]],
+    [int | None, str | None, str | None, int | None],
     IO[bytes],
 ]
 
 ParserFunc = Callable[
-    ["FormDataParser", "Body", str, Optional[int], dict[str, str]],
+    ["FormDataParser", "Body", str, int | None, dict[str, str]],
     Awaitable[tuple[MultiDict, MultiDict]],
 ]
 

src/quart/helpers.py

@@ -4,6 +4,7 @@
 import os
 import pkgutil
 import sys
+from collections.abc import Callable
 from collections.abc import Iterable
 from datetime import datetime
 from datetime import timedelta
@@ -13,7 +14,6 @@
 from io import BytesIO
 from pathlib import Path
 from typing import Any
-from typing import Callable
 from typing import cast
 from typing import NoReturn
 from zlib import adler32