d8948c5e09
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.
(cherry picked from commit
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|---|---|---|
| .. | ||
| NEWS.d | ||
| ACKS | ||
| HISTORY | ||
| Porting | ||
| README | ||
| README.AIX | ||
| README.coverity | ||
| README.valgrind | ||
| SpecialBuilds.txt | ||
| coverity_model.c | ||
| gdbinit | ||
| indent.pro | ||
| python-config.in | ||
| python-config.sh.in | ||
| python-wing3.wpr | ||
| python-wing4.wpr | ||
| python-wing5.wpr | ||
| python.man | ||
| python.pc.in | ||
| svnmap.txt | ||
| valgrind-python.supp | ||
| vgrindefs | ||
README
Python Misc subdirectory
========================
This directory contains files that wouldn't fit in elsewhere. Some
documents are only of historic importance.
Files found here
----------------
ACKS Acknowledgements
gdbinit Handy stuff to put in your .gdbinit file, if you use gdb
HISTORY News from previous releases -- oldest last
indent.pro GNU indent profile approximating my C style
NEWS News for this release (for some meaning of "this")
Porting Mini-FAQ on porting to new platforms
python-config.in Python script template for python-config
python.man UNIX man page for the python interpreter
python.pc.in Package configuration info template for pkg-config
python-wing*.wpr Wing IDE project file
README The file you're reading now
README.AIX Information about using Python on AIX
README.coverity Information about running Coverity's Prevent on Python
README.valgrind Information for Valgrind users, see valgrind-python.supp
SpecialBuilds.txt Describes extra symbols you can set for debug builds
svnmap.txt Map of old SVN revs and branches to hg changeset ids,
help history-digging
valgrind-python.supp Valgrind suppression file, see README.valgrind
vgrindefs Python configuration for vgrind (a generic pretty printer)