These changes updates the doc to comprehensively mention the behaviour of gather.cancel()
Automerge-Triggered-By: @asvetlov
(cherry picked from commit d42528a3a2)
Co-authored-by: Vinay Sharma <vinay04sharma@icloud.com>
When I wrote the documentation for `asyncio.to_thread()`, I mistakenly assumed that `return await loop.run_in_executor(...)` within an async def function would return a Future. In reality, it returns a coroutine.
This likely won't affect typical usage of `asyncio.to_thread()`, but it's important for the documentation to be correct here. In general, we also tend to avoid returning futures from high-level APIs in asyncio.
(cherry picked from commit 2b201369b4)
Co-authored-by: Kyle Stanley <aeros167@gmail.com>
Allows contextvars from the main thread to be accessed in the separate thread used in `asyncio.to_thread()`. See the [discussion](https://github.com/python/cpython/pull/20143GH-discussion_r427808225) in GH-20143 for context.
Automerge-Triggered-By: @aeros
(cherry picked from commit 0f56263e62)
Co-authored-by: Kyle Stanley <aeros167@gmail.com>
Implements `asyncio.to_thread`, a coroutine for asynchronously running IO-bound functions in a separate thread without blocking the event loop. See the discussion starting from [here](https://github.com/python/cpython/pull/18410GH-issuecomment-628930973) in GH-18410 for context.
Automerge-Triggered-By: @aeros
(cherry picked from commit cc2bbc2227)
Co-authored-by: Kyle Stanley <aeros167@gmail.com>
When an asyncio.Task is cancelled, the exception traceback now
starts with where the task was first interrupted. Previously,
the traceback only had "depth one."
Currently, if asyncio.wait_for() timeout expires, it cancels
inner future and then always raises TimeoutError. In case
those future is task, it can handle cancelation mannually,
and those process can lead to some other exception. Current
implementation silently loses thoses exception.
To resolve this, wait_for will check was the cancelation
successfull or not. In case there was exception, wait_for
will reraise it.
Co-authored-by: Roman Skurikhin <roman.skurikhin@cruxlab.com>
Motivation for this PR (comment from @vstinner in bpo issue):
```
Warning seen o AMD64 Ubuntu Shared 3.x buildbot:
https://buildbot.python.org/all/#/builders/141/builds/2593
test_devnull_output (test.test_a=syncio.test_subprocess.SubprocessThreadedWatcherTests) ...
Warning -- threading_cleanup() failed to cleanup 1 threads (count: 1, dangling: 2)
```
The following implementation details for the new method are TBD:
1) Public vs private
2) Inclusion in `close()`
3) Name
4) Coroutine vs subroutine method
5) *timeout* parameter
If it's a private method, 3, 4, and 5 are significantly less important.
I started with the most minimal implementation that fixes the dangling threads without modifying the regression tests, which I think is particularly important. I typically try to avoid directly modifying existing tests as much as possible unless it's necessary to do so. However, I am open to changing any part of this.
https://bugs.python.org/issue38356
If waitpid() is called elsewhere, waitpid() call fails with
ChildProcessError: use return code 255 in this case, and log a
warning. It ensure that the pidfd file descriptor is closed if this
error occurs.
Capturing exceptions into names can lead to reference cycles though the __traceback__ attribute of the exceptions in some obscure cases that have been reported previously and fixed individually. As these variables are not used anyway, we can remove the binding to reduce the chances of creating reference cycles.
See for example GH-13135
* This just copies the docs from `StreamWriter` and `StreamReader`.
* Add docstring for asyncio functions.
https://bugs.python.org/issue36889
Automerge-Triggered-By: @asvetlov
This PR deprecate explicit loop parameters in all public asyncio APIs
This issues is split to be easier to review.
fourth step: queue.py
https://bugs.python.org/issue36373
This PR deprecate explicit loop parameters in all public asyncio APIs
This issues is split to be easier to review.
Third step: locks.py
https://bugs.python.org/issue36373
