if parent `__init__` is not called from a constructor of object derived from `asyncio.Future`
https://bugs.python.org/issue38785
(cherry picked from commit dad6be5ffe)
Co-authored-by: Andrew Svetlov <andrew.svetlov@gmail.com>
Specifically, it's not possible to subclass Task/Future classes
and override the following methods:
* Future._schedule_callbacks
* Task._step
* Task._wakeup
The asyncio/compat.py file was written to support Python < 3.5 and
Python < 3.5.2. But Python 3.5 doesn't accept bugfixes anymore, only
security fixes. There is no more need to backport bugfixes to Python
3.5, and so no need to have a single code base for Python 3.5, 3.6
and 3.7.
Say hello (again) to "async" and "await", who became real keywords in
Python 3.7 ;-)
This implementation provides additional 10-20% speed boost for
asyncio programs.
The patch also fixes _asynciomodule.c to use Arguments Clinic, and
makes '_schedule_callbacks' an overridable method (as it was in 3.5).
This is now an official "protected" API that can be used to write
classes that are duck-type-compatible with Future without subclassing
it. (For that purpose I also changed isinstance(result, Future) to
check for this attribute instead.)
Hopefully Amber Brown can use this to make Twisted.Deferred compatible
with asyncio.Future.
Tests and docs are TBD.
* Tulip issue 184: FlowControlMixin constructor now get the event loop if the
loop parameter is not set. Add unit tests to ensure that constructor of
StreamReader and StreamReaderProtocol classes get the event loop.
* Remove outdated TODO/XXX
* _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
Handle objects are created. Pass the traceback to call_exception_handler() in
the 'source_traceback' key.
The traceback is truncated to hide internal calls in asyncio, show only the
traceback from user code.
Add tests for the new source_traceback, and a test for the 'Future/Task
exception was never retrieved' log.
Miss Islington (bot)
Andrew Svetlov
Yury Selivanov
Victor Stinner
Antoine Pitrou
INADA Naoki
INADA Naoki
Guido van Rossum
Yury Selivanov
Martin Panter
Serhiy Storchaka