The main problem was that an unluckily timed task cancellation could cause
the semaphore to be stuck. There were also doubts about strict FIFO ordering
of tasks allowed to pass.
The Semaphore implementation was rewritten to be more similar to Lock.
Many tests for edge cases (including cancellation) were added.
Remove the @asyncio.coroutine decorator
enabling legacy generator-based coroutines to be compatible with async/await
code; remove asyncio.coroutines.CoroWrapper used for wrapping
legacy coroutine objects in the debug mode.
The decorator has been deprecated
since Python 3.8 and the removal was initially scheduled for Python 3.10.
* Update code after merge review from 1st1
* Use a sentinel approach for loop parameter
Remove unnecessary _get_running_loop patching
* Use more clear function name (_verify_parameter_is_marker -> _verify_no_loop)
* Add init method to _LoopBoundMixin to check that loop param wasn't used
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
Currently, asyncio.wait_for(fut), upon reaching the timeout deadline,
cancels the future and returns immediately. This is problematic for
when *fut* is a Task, because it will be left running for an arbitrary
amount of time. This behavior is iself surprising and may lead to
related bugs such as the one described in bpo-33638:
condition = asyncio.Condition()
async with condition:
await asyncio.wait_for(condition.wait(), timeout=0.5)
Currently, instead of raising a TimeoutError, the above code will fail
with `RuntimeError: cannot wait on un-acquired lock`, because
`__aexit__` is reached _before_ `condition.wait()` finishes its
cancellation and re-acquires the condition lock.
To resolve this, make `wait_for` await for the task cancellation.
The tradeoff here is that the `timeout` promise may be broken if the
task decides to handle its cancellation in a slow way. This represents
a behavior change and should probably not be back-patched to 3.6 and
earlier.
* Convert asyncio/tasks.py to async/await
* Convert asyncio/queues.py to async/await
* Convert asyncio/test_utils.py to async/await
* Convert asyncio/base_subprocess.py to async/await
* Convert asyncio/subprocess.py to async/await
* Convert asyncio/streams.py to async/await
* Fix comments
* Convert asyncio/locks.py to async/await
* Convert asyncio.sleep to async def
* Add a comment
* Add missing news
* Convert stubs from AbstrctEventLoop to async functions
* Convert subprocess_shell/subprocess_exec
* Convert connect_read_pipe/connect_write_pip to async/await syntax
* Convert create_datagram_endpoint
* Convert create_unix_server/create_unix_connection
* Get rid of old style coroutines in unix_events.py
* Convert selector_events.py to async/await
* Convert wait_closed and create_connection
* Drop redundant line
* Convert base_events.py
* Code cleanup
* Drop redundant comments
* Fix indentation
* Add explicit tests for compatibility between old and new coroutines
* Convert windows event loop to use async/await
* Fix double awaiting of async function
* Convert asyncio/locks.py
* Improve docstring
* Convert tests to async/await
* Convert more tests
* Convert more tests
* Convert more tests
* Convert tests
* Improve test
* _WaitHandleFuture.cancel() now notify IocpProactor through the overlapped
object that the wait was cancelled.
* Optimize IocpProactor.wait_for_handle() gets the result if the wait is
signaled immediatly.
* Enhance representation of Future and Future subclasses
- Add "created at filename:lineno" in the representation
- Add Future._repr_info() method which can be more easily overriden than
Future.__repr__(). It should now be more easy to enhance Future
representation without having to modify each subclass. For example,
_OverlappedFuture and _WaitHandleFuture get the new "created at" information.
- Use reprlib to format Future result, and function arguments when formatting a
callback, to limit the length of the representation.
* Fix repr(_WaitHandleFuture)
* _WaitHandleFuture and _OverlappedFuture: hide frames of internal calls in the
source traceback.
* Cleanup ProactorIocp._poll(): set the timeout to 0 after the first call to
GetQueuedCompletionStatus()
* test_locks: close the temporary event loop and check the condition lock
* Remove workaround in test_futures, no more needed
Major changes:
- StreamReader.readexactly() now raises an IncompleteReadError if the
end of stream is reached before we received enough bytes, instead of
returning less bytes than requested.
- Unit tests use the main asyncio module instead of submodules like events
- _UnixWritePipeTransport now also supports character devices, as
_UnixReadPipeTransport. Patch written by Jonathan Slenders.
- Export more symbols: BaseEventLoop, BaseProactorEventLoop,
BaseSelectorEventLoop, Queue and Queue sublasses, Empty, Full
Kristján Valur Jónsson
Cyker Way
Akuli
Duprat
Andrew Svetlov
Serhiy Storchaka
Joongi Kim
Illia Volochii
Yurii Karabas
Emmanuel Arias
Yury Selivanov
Brett Cannon
Elvis Pranskevichus
Bar Harel
Mathieu Sornay
Martin Panter
Guido van Rossum
Victor Stinner
Guido van Rossum