Assertion error when current_task() returns an instance of _asyncio.Task
#840
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bug
Something isn't working
Comments
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What is |
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Can you at least post the traceback? |
An instance of
Sure, sorry about not sharing them before Here you go Traceback
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So how does that make any sense? It's checking if |
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Are you using a custom task factory or something? |
It's an instance of (Pdb) key
<Task finished name='Task-47' coro=<test_google_callback() done, defined at /Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/unittest/mock.py:1408> exception=AssertionError("assert False\n + where False = isinstance(<Task pending name='Task-47' coro=<test_google_callback() running at /Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/unittest/mock.py:1413> cb=[_run_until_complete_cb() at /Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/asyncio/base_events.py:181]>, <class 'asyncio.tasks.Task'>)\n + where <class 'asyncio.tasks.Task'> = asyncio.Task")>
(Pdb) type(key)
<class '_asyncio.Task'>
We are using something like def async_to_sync(
func: Callable[_P, Coroutine[Any, Any, _R]],
) -> Callable[_P, _R]:
"""Decorator to convert an async function to a sync function using `asyncio.run`."""
@wraps(func)
def _decorator(*args: _P.args, **kwargs: _P.kwargs) -> _R:
loop = asyncio.get_event_loop()
nest_asyncio.apply(loop)
return loop.run_until_complete(func(*args, **kwargs))
return _decorator
class ItemGetter:
@async_to_sync
async def __getitem__(self, key: str):
return ...and then an instance of class ItemGetter:
async def get(self, key: str):
return ...
@pytest.mark.asyncio()
async def test_example(getter):
item = getter.get(...) |
Yes, that is the type of all asyncio tasks: >>> from asyncio import run, current_task
>>> async def foo():
... task = current_task()
... print(type(task))
...
>>> run(foo())
<class '_asyncio.Task'> |
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Wait, is |
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No, probably not. At any rate, you need to either come up with a MWE or figure out why the assert fails. |
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Did you run nest-asyncio or something similar that replaced asyncio.Task with PyTask? I think the assertion should be less strict and support anything hashable with a get_coro method |
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I saw this issue yesterday while using the PyCharm, anyio 4.7.0. I posted this to the PyCharm tracker first. However, I cannot replicate today. Strange. Here is the snippet: from pathlib import Path
import anyio
import uvicorn
from starlette.applications import Starlette
from starlette.responses import PlainTextResponse
from starlette.routing import Route
f = (Path(__file__).parent / "tmp")
f.write_text("hello")
async def read(file):
async with await anyio.open_file(file) as f:
content = await f.read()
return content
async def homepage(request):
res = await read(f)
# set breakpoint on return statement
return PlainTextResponse(f'{res}, world!')
if __name__ == '__main__':
routes = [
Route('/', homepage),
]
app = Starlette(routes=routes)
uvicorn.run(app, port=8080) |
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We also found related issue in our project. Here it is: taskiq-python/taskiq#387 As people claim, it only happens on 4.7.0. I could narrow down the MRE to this code: import asyncio
import nest_asyncio
import anyio
async def test_func():
await asyncio.sleep(1)
async def main():
nest_asyncio.apply()
async with anyio.create_task_group() as tg:
tg.start_soon(test_func)
if __name__ == "__main__":
asyncio.run(main())Here is the setup: I tried running this code on |
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I figured out what's happening here. It seems that import asyncio
import nest_asyncio
import anyio
async def test_func():
await asyncio.sleep(1)
async def main():
async with anyio.create_task_group() as tg:
tg.start_soon(test_func)
if __name__ == "__main__":
nest_asyncio.apply()
asyncio.run(main())The above snippet works fine. |
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By the way, may I ask what you're using |
agronholm
added a commit
that referenced
this issue
Dec 15, 2024
This stems from the incorrect placement of `nest_asyncio.apply()`, as it should be called before `asyncio.run()`. Fixes #840.
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For me, it seems to be part of the PyCharm debugger, and it’s used to be able to run coroutines in the debug console. |
3 tasks
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Would you mind verifying that the linked PR works for you? |
sigridjineth
added a commit
to sigridjineth/anyio
that referenced
this issue
Dec 17, 2024
…ecks Expects to fix agronholm#840 This commit removes the strict `isinstance(key, asyncio.Task)` checks in the TaskStateStore implementation and replaces them with a more flexible approach based on the presence of `get_coro()` and `asyncio.iscoroutine()`. By doing so, we eliminate AssertionErrors that arise when alternative task implementations (e.g., due to `nest_asyncio`, custom factories, or debugger wrappers) return objects that are not instances of `asyncio.Task` but still behave like them. This change significantly improves compatibility with monkey-patched environments and non-standard asyncio task implementations.
3 tasks
mkjpryor
pushed a commit
to azimuth-cloud/azimuth
that referenced
this issue
Jan 7, 2025
[//]: # (dependabot-start)⚠️ **Dependabot is rebasing this PR**⚠️ Rebasing might not happen immediately, so don't worry if this takes some time. Note: if you make any changes to this PR yourself, they will take precedence over the rebase. --- [//]: # (dependabot-end) Bumps [anyio](https://github.com/agronholm/anyio) from 4.7.0 to 4.8.0. <details> <summary>Release notes</summary> <p><em>Sourced from <a href="https://github.com/agronholm/anyio/releases">anyio's releases</a>.</em></p> <blockquote> <h2>4.8.0</h2> <ul> <li>Added <strong>experimental</strong> support for running functions in subinterpreters on Python 3.13 and later</li> <li>Added support for the <code>copy()</code>, <code>copy_into()</code>, <code>move()</code> and <code>move_into()</code> methods in <code>anyio.Path</code>, available in Python 3.14</li> <li>Changed <code>TaskGroup</code> on asyncio to always spawn tasks non-eagerly, even if using a task factory created via <code>asyncio.create_eager_task_factory()</code>, to preserve expected Trio-like task scheduling semantics (PR by <a href="https://github.com/agronholm"><code>@agronholm</code></a> and <a href="https://github.com/graingert"><code>@graingert</code></a>)</li> <li>Configure <code>SO_RCVBUF</code>, <code>SO_SNDBUF</code> and <code>TCP_NODELAY</code> on the selector thread waker socket pair (this should improve the performance of <code>wait_readable()</code> and <code>wait_writable()</code> when using the <code>ProactorEventLoop</code>) (<a href="https://redirect.github.com/agronholm/anyio/pull/836">#836</a>; PR by <a href="https://github.com/graingert"><code>@graingert</code></a>)</li> <li>Fixed <code>AssertionError</code> when using <code>nest-asyncio</code> (<a href="https://redirect.github.com/agronholm/anyio/issues/840">#840</a>)</li> <li>Fixed return type annotation of various context managers' <code>__exit__</code> method (<a href="https://redirect.github.com/agronholm/anyio/issues/847">#847</a>; PR by <a href="https://github.com/Enegg"><code>@Enegg</code></a>)</li> </ul> </blockquote> </details> <details> <summary>Changelog</summary> <p><em>Sourced from <a href="https://github.com/agronholm/anyio/blob/master/docs/versionhistory.rst">anyio's changelog</a>.</em></p> <blockquote> <h1>Version history</h1> <p>This library adheres to <code>Semantic Versioning 2.0 <http://semver.org/></code>_.</p> <p><strong>4.8.0</strong></p> <ul> <li>Added <strong>experimental</strong> support for running functions in subinterpreters on Python 3.13 and later</li> <li>Added support for the <code>copy()</code>, <code>copy_into()</code>, <code>move()</code> and <code>move_into()</code> methods in <code>anyio.Path</code>, available in Python 3.14</li> <li>Changed <code>TaskGroup</code> on asyncio to always spawn tasks non-eagerly, even if using a task factory created via <code>asyncio.create_eager_task_factory()</code>, to preserve expected Trio-like task scheduling semantics (PR by <a href="https://github.com/agronholm"><code>@agronholm</code></a> and <a href="https://github.com/graingert"><code>@graingert</code></a>)</li> <li>Configure <code>SO_RCVBUF</code>, <code>SO_SNDBUF</code> and <code>TCP_NODELAY</code> on the selector thread waker socket pair (this should improve the performance of <code>wait_readable()</code>) and <code>wait_writable()</code> when using the <code>ProactorEventLoop</code> (<code>[#836](agronholm/anyio#836) <https://github.com/agronholm/anyio/pull/836></code>_; PR by <a href="https://github.com/graingert"><code>@graingert</code></a>)</li> <li>Fixed <code>AssertionError</code> when using <code>nest-asyncio</code> (<code>[#840](agronholm/anyio#840) <https://github.com/agronholm/anyio/issues/840></code>_)</li> <li>Fixed return type annotation of various context managers' <code>__exit__</code> method (<code>[#847](agronholm/anyio#847) <https://github.com/agronholm/anyio/issues/847></code>_; PR by <a href="https://github.com/Enegg"><code>@Enegg</code></a>)</li> </ul> <p><strong>4.7.0</strong></p> <ul> <li>Updated <code>TaskGroup</code> to work with asyncio's eager task factories (<code>[#764](agronholm/anyio#764) <https://github.com/agronholm/anyio/issues/764></code>_)</li> <li>Added the <code>wait_readable()</code> and <code>wait_writable()</code> functions which will accept an object with a <code>.fileno()</code> method or an integer handle, and deprecated their now obsolete versions (<code>wait_socket_readable()</code> and <code>wait_socket_writable()</code>) (PR by <a href="https://github.com/davidbrochart"><code>@davidbrochart</code></a>)</li> <li>Changed <code>EventAdapter</code> (an <code>Event</code> with no bound async backend) to allow <code>set()</code> to work even before an async backend is bound to it (<code>[#819](agronholm/anyio#819) <https://github.com/agronholm/anyio/issues/819></code>_)</li> <li>Added support for <code>wait_readable()</code> and <code>wait_writable()</code> on <code>ProactorEventLoop</code> (used on asyncio + Windows by default)</li> <li>Fixed a misleading <code>ValueError</code> in the context of DNS failures (<code>[#815](agronholm/anyio#815) <https://github.com/agronholm/anyio/issues/815></code>_; PR by <a href="https://github.com/graingert"><code>@graingert</code></a>)</li> <li>Fixed the return type annotations of <code>readinto()</code> and <code>readinto1()</code> methods in the <code>anyio.AsyncFile</code> class (<code>[#825](agronholm/anyio#825) <https://github.com/agronholm/anyio/issues/825></code>_)</li> <li>Fixed <code>TaskInfo.has_pending_cancellation()</code> on asyncio returning false positives in cleanup code on Python >= 3.11 (<code>[#832](agronholm/anyio#832) <https://github.com/agronholm/anyio/issues/832></code>_; PR by <a href="https://github.com/gschaffner"><code>@gschaffner</code></a>)</li> <li>Fixed cancelled cancel scopes on asyncio calling <code>asyncio.Task.uncancel</code> when propagating a <code>CancelledError</code> on exit to a cancelled parent scope (<code>[#790](agronholm/anyio#790) <https://github.com/agronholm/anyio/pull/790></code>_; PR by <a href="https://github.com/gschaffner"><code>@gschaffner</code></a>)</li> </ul> <p><strong>4.6.2</strong></p> <!-- raw HTML omitted --> </blockquote> <p>... (truncated)</p> </details> <details> <summary>Commits</summary> <ul> <li><a href="https://github.com/agronholm/anyio/commit/74022ec53cde6c2e5d7441de37d5a0dcf9d6daad"><code>74022ec</code></a> Bumped up the version</li> <li><a href="https://github.com/agronholm/anyio/commit/264a6f9f911ebd5a6b7d9d79dfa4bf91ac5d8ceb"><code>264a6f9</code></a> Added support for subinterpreter workers (<a href="https://redirect.github.com/agronholm/anyio/issues/850">#850</a>)</li> <li><a href="https://github.com/agronholm/anyio/commit/6d612a9fbd037352507209543bc8dde6462f62d6"><code>6d612a9</code></a> Refactored waiting for tasks to complete from task group on the asyncio backe...</li> <li><a href="https://github.com/agronholm/anyio/commit/8b7a5352aec2c0cdd2f9a991da601f2f5b22cf8b"><code>8b7a535</code></a> Removed the unwarranted gc_collect fixture</li> <li><a href="https://github.com/agronholm/anyio/commit/acdac7abf59761a77e17738abfabbda9dea68ad7"><code>acdac7a</code></a> Changed TaskGroup to always spawn tasks lazily, even with eager task factorie...</li> <li><a href="https://github.com/agronholm/anyio/commit/43e1f5fd133b2f53993d606af207b06a0d09fecc"><code>43e1f5f</code></a> Fixed <code>__exit__()</code> return type of various context managers (<a href="https://redirect.github.com/agronholm/anyio/issues/849">#849</a>)</li> <li><a href="https://github.com/agronholm/anyio/commit/e8730ae116aa924b0386fef15dcb3a7c15490283"><code>e8730ae</code></a> Added preliminary support for Python 3.14 (<a href="https://redirect.github.com/agronholm/anyio/issues/813">#813</a>)</li> <li><a href="https://github.com/agronholm/anyio/commit/9a792f3568f450ad97363d7bf0baa04f768ae291"><code>9a792f3</code></a> Pruned unnecessary mypy options</li> <li><a href="https://github.com/agronholm/anyio/commit/2a105b2bc6ebb4d12b67b4c9c1777ff5cc54f42b"><code>2a105b2</code></a> Updated downstream test workflow</li> <li><a href="https://github.com/agronholm/anyio/commit/3f8c639d36d0ac01d341b25f6f99f1bc7aff6d12"><code>3f8c639</code></a> [pre-commit.ci] pre-commit autoupdate (<a href="https://redirect.github.com/agronholm/anyio/issues/846">#846</a>)</li> <li>Additional commits viewable in <a href="https://github.com/agronholm/anyio/compare/4.7.0...4.8.0">compare view</a></li> </ul> </details> <br /> [](https://docs.github.com/en/github/managing-security-vulnerabilities/about-dependabot-security-updates#about-compatibility-scores) Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. 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Things to check first
I have searched the existing issues and didn't find my bug already reported there
I have checked that my bug is still present in the latest release
AnyIO version
4.7.0
Python version
3.12.8
What happened?
It seems that sometimes when
asyncio.current_task()is called inanyio/src/anyio/_backends/_asyncio.py
Line 2367 in 97f0642
an instance of
_asyncio.Taskis returned. This then causes an assertion to be raised inanyio/src/anyio/_backends/_asyncio.py
Lines 685 to 694 in 97f0642
How can we reproduce the bug?
This is triggered in our test suite (fastapi, httpx, pytest-asyncio) after upgrading to anyio 4.7.0, but I haven't been able to come up with a MRE so hopefully this is enough to point maintainers to the potential fix.
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