* gh-117151: increase default buffer size of shutil.copyfileobj() to 256k.
it was set to 16k in the 1990s.
it was raised to 64k in 2019. the discussion at the time mentioned another 5% improvement by raising to 128k and settled for a very conservative setting.
it's 2024 now, I think it should be revisited to match modern hardware. I am measuring 0-15% performance improvement when raising to 256k on various types of disk. there is no downside as far as I can tell.
this function is only intended for sequential copy of full files (or file like objects). it's the typical use case that benefits from larger operations.
for reference, I came across this function while trying to profile pip that is using it to copy files when installing python packages.
* add news
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Co-authored-by: rmorotti <romain.morotti@man.com>
Instead of surprise crashes and memory corruption, we now hang threads that attempt to re-enter the Python interpreter after Python runtime finalization has started. These are typically daemon threads (our long standing mis-feature) but could also be threads spawned by extension modules that then try to call into Python. This marks the `PyThread_exit_thread` public C API as deprecated as there is no plausible safe way to accomplish that on any supported platform in the face of things like C++ code with finalizers anywhere on a thread's stack. Doing this was the least bad option.
Co-authored-by: Gregory P. Smith <greg@krypto.org>
This is actually an upstream problem in curses, and has been reported
to them already:
https://lists.gnu.org/archive/html/bug-ncurses/2024-09/msg00101.html
This is a nice workaround in the meantime to prevent the segfault.
Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
Previously, formatting help output or error message for positional argument
with a tuple metavar raised exception.
Co-authored-by: Cyker Way <cykerway@gmail.com>
It can now have one of three forms:
* basename(argv0) -- for simple scripts
* python arv0 -- for directories, ZIP files, etc
* python -m module -- for imported modules
Co-authored-by: Alyssa Coghlan <ncoghlan@gmail.com>
This is to allow the `dataclasses.make_dataclass` infrastructure to be used with another decorator that's compliant with `typing.dataclass_transform`. The new `decorator` argument to `dataclasses.make_dataclass` is `dataclasses.dataclass`, which used to be hard coded.
* Revert "GH-124639: add back loop param to staggered_race (#124700)"
This reverts commit e0a41a5dd1.
* Revert "gh-124309: Modernize the `staggered_race` implementation to support eager task factories (#124390)"
This reverts commit de929f353c.
Resolve a memory leak introduced in CPython 3.10's :mod:`ssl` when the :attr:`ssl.SSLSocket.session` property was accessed. Speeds up read and write access to said property by no longer unnecessarily cloning session objects via serialization.
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
Co-authored-by: Peter Bierma <zintensitydev@gmail.com>
Co-authored-by: Gregory P. Smith <greg@krypto.org>
Co-authored-by: Antoine Pitrou <antoine@python.org>
Positional arguments with nargs equal to '?' or '*' no longer check
default against choices.
Optional arguments with nargs equal to '?' no longer check const
against choices.
* Setting the __module__ attribute for a class now removes the
__firstlineno__ item from the type's dict.
* The _collections_abc and _pydecimal modules now completely replace the
collections.abc and decimal modules after importing them. This
allows to get the source of classes and functions defined in these
modules.
* inspect.findsource() now checks whether the first line number for a
class is out of bound.
Fix a bug that can cause a crash when sub-interpreters use "basic"
single-phase extension modules. Shared objects could refer to PyGC_Head
nodes that had been freed as part of interpreter shutdown.
Change the default multiprocessing start method away from fork to forkserver or spawn on the remaining platforms where it was fork. See the issue for context. This makes the default far more thread safe (other than for people spawning threads at import time... - don't do that!).
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
Tomas R.
Tian Gao
morotti
Irit Katriel
Bénédikt Tran
Thomas Grainger
Brandt Bucher
Diego Russo
Jeremy Maitin-Shepard
Peter Bierma
Serhiy Storchaka
Taneli Hukkinen
Sam Gross
Bartosz Sławecki
Victorien
T. Wouters
Jeffrey R. Van Voorst
Steve Dower
Dino Viehland
Ned Deily
Kira
Mark Shannon
Mariatta
Tony Roberts
sobolevn
Malcolm Smith
Jelle Zijlstra
Neil Schemenauer
Savannah Ostrowski
Gregory P. Smith
Ron Frederick
dgpb
Nice Zombies