From ac34de0c56e6eaa8b6d04dcbfca993e5ce372add Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20Gr=C3=B6nholm?= <alex.gronholm@nextday.fi>
Date: Sat, 20 Jan 2024 17:23:42 +0200
Subject: [PATCH] Fixed inability to start tasks from async_generator_asend
 objects on asyncio

---
 docs/versionhistory.rst         |  1 +
 src/anyio/_backends/_asyncio.py |  6 ++----
 tests/test_taskgroups.py        | 16 ++++++++++++++++
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/docs/versionhistory.rst b/docs/versionhistory.rst
index 5d39e459..5b8c6647 100644
--- a/docs/versionhistory.rst
+++ b/docs/versionhistory.rst
@@ -10,6 +10,7 @@ This library adheres to `Semantic Versioning 2.0 <http://semver.org/>`_.
 - Fixed passing ``total_tokens`` to ``anyio.CapacityLimiter()`` as a keyword argument
   not working on the ``trio`` backend
   (`#515 <https://github.com/agronholm/anyio/issues/515>`_)
+- Fixed inability to start tasks from ``async_generator_asend`` objects on asyncio
 
 **4.2.0**
 
diff --git a/src/anyio/_backends/_asyncio.py b/src/anyio/_backends/_asyncio.py
index e884f564..ff1fc982 100644
--- a/src/anyio/_backends/_asyncio.py
+++ b/src/anyio/_backends/_asyncio.py
@@ -18,7 +18,7 @@
 )
 from asyncio.base_events import _run_until_complete_cb  # type: ignore[attr-defined]
 from collections import OrderedDict, deque
-from collections.abc import AsyncIterator, Generator, Iterable
+from collections.abc import AsyncIterator, Coroutine, Generator, Iterable
 from concurrent.futures import Future
 from contextlib import suppress
 from contextvars import Context, copy_context
@@ -28,7 +28,6 @@
     CORO_RUNNING,
     CORO_SUSPENDED,
     getcoroutinestate,
-    iscoroutine,
 )
 from io import IOBase
 from os import PathLike
@@ -45,7 +44,6 @@
     Callable,
     Collection,
     ContextManager,
-    Coroutine,
     Mapping,
     Optional,
     Sequence,
@@ -741,7 +739,7 @@ def task_done(_task: asyncio.Task) -> None:
             parent_id = id(self.cancel_scope._host_task)
 
         coro = func(*args, **kwargs)
-        if not iscoroutine(coro):
+        if not isinstance(coro, Coroutine):
             prefix = f"{func.__module__}." if hasattr(func, "__module__") else ""
             raise TypeError(
                 f"Expected {prefix}{func.__qualname__}() to return a coroutine, but "
diff --git a/tests/test_taskgroups.py b/tests/test_taskgroups.py
index f4c87b39..ede649e4 100644
--- a/tests/test_taskgroups.py
+++ b/tests/test_taskgroups.py
@@ -1336,6 +1336,22 @@ async def wait_cancel() -> None:
                 await cancelled.wait()
 
 
+async def test_start_soon_from_asend() -> None:
+    started = False
+
+    async def genfunc() -> AsyncGenerator[None, None]:
+        nonlocal started
+        started = True
+        yield
+
+    generator = genfunc()
+    async with anyio.create_task_group() as task_group:
+        task_group.start_soon(generator.asend, None)
+
+    assert started
+    await generator.aclose()
+
+
 class TestTaskStatusTyping:
     """
     These tests do not do anything at run time, but since the test suite is also checked