Added support for asyncio eager task factories

Fixes #764.

.pre-commit-config.yaml

@@ -22,14 +22,14 @@ repos:
       - id: trailing-whitespace
 
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.6.9
+    rev: v0.7.1
     hooks:
       - id: ruff
         args: [--fix, --show-fixes]
       - id: ruff-format
 
   - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v1.11.2
+    rev: v1.13.0
     hooks:
       - id: mypy
         additional_dependencies:

docs/versionhistory.rst

@@ -5,6 +5,12 @@ This library adheres to `Semantic Versioning 2.0 <http://semver.org/>`_.
 
 **UNRELEASED**
 
+- Added support for asyncio's eager task factories:
+
+  * Updated the annotation of ``TaskInfo.coro`` to allow it to be ``None``
+  * Updated ``TaskGroup`` to work with asyncio eager task factories
+
+  (`#764 <https://github.com/agronholm/anyio/issues/764>`_)
 - Fixed a misleading ``ValueError`` in the context of DNS failures
   (`#815 <https://github.com/agronholm/anyio/issues/815>`_; PR by @graingert)
 

src/anyio/_backends/_asyncio.py

@@ -347,8 +347,12 @@ def get_callable_name(func: Callable) -> str:
 
 def _task_started(task: asyncio.Task) -> bool:
     """Return ``True`` if the task has been started and has not finished."""
+    # The task coro should never be None here, as we never add finished tasks to the
+    # task list
+    coro = task.get_coro()
+    assert coro is not None
     try:
-        return getcoroutinestate(task.get_coro()) in (CORO_RUNNING, CORO_SUSPENDED)
+        return getcoroutinestate(coro) in (CORO_RUNNING, CORO_SUSPENDED)
     except AttributeError:
         # task coro is async_genenerator_asend https://bugs.python.org/issue37771
         raise Exception(f"Cannot determine if task {task} has started or not") from None
@@ -842,14 +846,14 @@ def task_done(_task: asyncio.Task) -> None:
 
         name = get_callable_name(func) if name is None else str(name)
         task = create_task(coro, name=name)
-        task.add_done_callback(task_done)
 
         # Make the spawned task inherit the task group's cancel scope
         _task_states[task] = TaskState(
             parent_id=parent_id, cancel_scope=self.cancel_scope
         )
         self.cancel_scope._tasks.add(task)
         self._tasks.add(task)
+        task.add_done_callback(task_done)
         return task
 
     def start_soon(

src/anyio/_core/_testing.py

@@ -24,14 +24,14 @@ def __init__(
         id: int,
         parent_id: int | None,
         name: str | None,
-        coro: Generator[Any, Any, Any] | Awaitable[Any],
+        coro: Generator[Any, Any, Any] | Awaitable[Any] | None,
     ):
         func = get_current_task
         self._name = f"{func.__module__}.{func.__qualname__}"
         self.id: int = id
         self.parent_id: int | None = parent_id
         self.name: str | None = name
-        self.coro: Generator[Any, Any, Any] | Awaitable[Any] = coro
+        self.coro: Generator[Any, Any, Any] | Awaitable[Any] | None = coro
 
     def __eq__(self, other: object) -> bool:
         if isinstance(other, TaskInfo):

tests/test_sockets.py

@@ -144,7 +144,7 @@ def _identity(v: _T) -> _T:
 )
 
 
-@_ignore_win32_resource_warnings  # type: ignore[operator]
+@_ignore_win32_resource_warnings
 class TestTCPStream:
     @pytest.fixture
     def server_sock(self, family: AnyIPAddressFamily) -> Iterator[socket.socket]:

tests/test_taskgroups.py

@@ -783,7 +783,7 @@ async def host_agen_fn() -> AsyncGenerator[None, None]:
     host_agen = host_agen_fn()
     try:
         loop = asyncio.get_running_loop()
-        await loop.create_task(host_agen.__anext__())  # type: ignore[arg-type]
+        await loop.create_task(host_agen.__anext__())
     finally:
         await host_agen.aclose()