This is needed to even the run the test suite on buildbots for affected platforms; e.g.:
```
./python.exe ./Tools/scripts/run_tests.py -j 1 -u all -W --slowest --fail-env-changed --timeout=11700 -j2
/home/embray/src/python/test-worker/3.x.test-worker/build/python -u -W default -bb -E -W error::BytesWarning -m test -r -w -j 1 -u all -W --slowest --fail-env-changed --timeout=11700 -j2
Traceback (most recent call last):
File "./Tools/scripts/run_tests.py", line 56, in <module>
main(sys.argv[1:])
File "./Tools/scripts/run_tests.py", line 52, in main
os.execv(sys.executable, args)
PermissionError: [Errno 13] Permission denied
make: *** [Makefile:1073: buildbottest] Error 1
```
The C implementation of asyncio.Task currently fails to perform the
cancellation cleanup correctly in the following scenario.
async def task1():
async def task2():
await task3 # task3 is never cancelled
asyncio.current_task().cancel()
await asyncio.create_task(task2())
The actuall error is a hardcoded call to `future_cancel()` instead of
calling the `cancel()` method of a future-like object.
Thanks to Vladimir Matveev for noticing the code discrepancy and to
Yury Selivanov for coming up with a pathological scenario.
Fix a reference issue inside multiprocessing.Pool that caused the pool to remain alive if it was deleted without being closed or terminated explicitly.
property_descr_get() uses a "cached" tuple to optimize function
calls. But this tuple can be discovered in debug mode with
sys.getobjects(). Remove the optimization, it's not really worth it
and it causes 3 different crashes last years.
Microbenchmark:
./python -m perf timeit -v \
-s "from collections import namedtuple; P = namedtuple('P', 'x y'); p = P(1, 2)" \
--duplicate 1024 "p.x"
Result:
Mean +- std dev: [ref] 32.8 ns +- 0.8 ns -> [patch] 40.4 ns +- 1.3 ns: 1.23x slower (+23%)
* Compiling a string annotation containing a lambda with keyword-only
argument without default value caused a crash.
* Remove the final "*" (it is incorrect syntax) in the representation of
lambda without *args and keyword-only arguments when compile from AST.
* Improve the representation of lambda without arguments.
The waiting is pretty normal for any asyncio program, logging its time just adds
a noise to logs without any useful information provided.
https://bugs.python.org/issue34849
After some failures in AMD64 FreeBSD CURRENT Debug 3.x buildbots
regarding tests in test_multiprocessing_spawn and after examining
similar failures in test_socket, some errors in the calculation of
ancillary data buffers were found in multiprocessing.reduction.
CMSG_LEN() can often be used as the buffer size for recvmsg() to
receive a single item of ancillary data, but RFC 3542 requires portable
applications to use CMSG_SPACE() and thus include space for padding,
even when the item will be the last in the buffer.
The failures we experience are due to the usage of CMSG_LEN() instead of
CMSG_SPACE().
Improvements:
1. Include the number of valid data characters in the error message.
2. Mention "number of data characters" rather than "length".
https://bugs.python.org/issue34736