This flag was added as an escape hatch in gh-91401 and backported to
Python 3.10. The flag broke at some point between its addition and now.
As there is currently no publicly known environments that require this,
remove it rather than work on fixing it.
This leaves the flag in the subprocess module to not break code which
may have used / checked the flag itself.
discussion: https://discuss.python.org/t/subprocess-use-vfork-escape-hatch-broken-fix-or-remove/56915/2
Tools such as ruff can ignore "imported but unused" warnings if a
line ends with "# noqa: F401". It avoids the temptation to remove
an import which is used effectively.
One more thing that can help prevent people from using `preexec_fn`.
Also adds conditional skips to two tests exposing ASAN flakiness on the Ubuntu 20.04 Address Sanitizer Github CI system. When that build is run on more modern systems the "problem" does not show up. It seems ASAN implementation related.
Co-authored-by: Zackery Spytz <zspytz@gmail.com>
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
Just in case there is ever an issue with _posixsubprocess's use of
vfork() due to the complexity of using it properly and potential
directions that Linux platforms where it defaults to on could take, this
adds a failsafe so that users can disable its use entirely by setting
a global flag.
No known reason to disable it exists. But it'd be a shame to encounter
one and not be able to use CPython without patching and rebuilding it.
See the linked issue for some discussion on reasoning.
Also documents the existing way to disable posix_spawn.
Multiprocessing and concurrent.futures tests now stop the resource
tracker process when tests complete.
Add ResourceTracker._stop() method to
multiprocessing.resource_tracker.
Add _cleanup_tests() helper function to multiprocessing.util: share
code between multiprocessing and concurrent.futures tests.
* subprocess: Add user, group and extra_groups paremeters to subprocess.Popen
This adds a `user` parameter to the Popen constructor that will call
setreuid() in the child before calling exec(). This allows processes
running as root to safely drop privileges before running the subprocess
without having to use a preexec_fn.
This also adds a `group` parameter that will call setregid() in
the child process before calling exec().
Finally an `extra_groups` parameter was added that will call
setgroups() to set the supplimental groups.
Fix multiprocessing.util.get_temp_dir() finalizer: clear also the
'tempdir' configuration of the current process, so next call to
get_temp_dir() will create a new temporary directory, rather than
reusing the removed temporary directory.
In some conditions the standard streams will be None or closed in the child process (for example if using "pythonw" instead of "python" on Windows). Avoid failing with a non-0 exit code in those conditions.
Report and initial patch by poxthegreat.
* Make error message more informative
Replace assertions in error-reporting code with more-informative version that doesn't cause confusion over where and what the error is.
* Additional clarification + get travis to check
* Change from SystemError to TypeError
As suggested in PR comment by @pitrou, changing from SystemError; TypeError appears appropriate.
* NEWS file installation; ACKS addition (will do my best to justify it by additional work)
* Making current AssertionErrors in multiprocessing more informative
* Blurb added re multiprocessing managers.py, queues.py cleanup
* Further multiprocessing cleanup - went through pool.py
* Fix two asserts in multiprocessing/util.py
* Most asserts in multiprocessing more informative
* Didn't save right version
* Further work on multiprocessing error messages
* Correct typo
* Correct typo v2
* Blasted colon... serves me right for trying to work on two things at once
* Simplify NEWS entry
* Update 2017-08-18-17-16-38.bpo-5001.gwnthq.rst
* Update 2017-08-18-17-16-38.bpo-5001.gwnthq.rst
OK, never mind.
* Corrected (thanks to pitrou) error messages for notify
* Remove extraneous backslash in docstring.
* bpo-24484: Avoid race condition in multiprocessing cleanup
The finalizer registry can be mutated while inspected by multiprocessing
at process exit.
* Use test.support.start_threads()
* Add Misc/NEWS
* multiprocessing: open file with closefd=False to avoid ResourceWarning
* _test_multiprocessing: open file with O_EXCL to detect bugs in tests (if a
previous test forgot to remove TESTFN)
* test_sys_exit(): remove TESTFN after each loop iteration
Initial patch written by Serhiy Storchaka.
In Python 3.2 and earlier, Process.join() and Connection.poll()
treated negative timeouts as zero timeouts. Earlier versions from
the 3.3 line of development treat them as infinite timeouts.
The patch reverts to the old behaviour.
