Neil Schemenauer [Sat, 13 Dec 2025 09:50:23 +0000 (01:50 -0800)]
gh-132657: Add lock-free set contains implementation (#132290)
This roughly follows what was done for dictobject to make a lock-free
lookup operation. With this change, the set contains operation scales much
better when used from multiple-threads. The frozenset contains performance
seems unchanged (as already lock-free).
Summary of changes:
* refactor set_lookkey() into set_do_lookup() which now takes a function
pointer that does the entry comparison. This is similar to dictobject and
do_lookup(). In an optimized build, the comparison function is inlined and
there should be no performance cost to this.
* change set_do_lookup() to return a status separately from the entry value
* add set_compare_frozenset() and use if the object is a frozenset. For the
free-threaded build, this avoids some overhead (locking, atomic operations,
incref/decref on key)
* use FT_ATOMIC_* macros as needed for atomic loads and stores
* use a deferred free on the set table array, if shared (only on free-threaded
build, normal build always does an immediate free)
* for free-threaded build, use explicit for loop to zero the table, rather than memcpy()
* when mutating the set, assign so->table to NULL while the change is a
happening. Assign the real table array after the change is done.
Alper [Fri, 12 Dec 2025 18:14:42 +0000 (10:14 -0800)]
gh-116738: Make zlib module thread-safe (gh-142432)
Makes the zlib module thread-safe free-threading build. Even though operations
are protected by locks, attributes exposed via PyMemberDef (eof, needs_input,
unused_data, unconsumed_tail) should still be stored atomically within locked
sections, since they can be read without acquiring the lock.
Sam Gross [Thu, 11 Dec 2025 21:23:19 +0000 (16:23 -0500)]
gh-142534: Avoid TSan warnings in dictobject.c (gh-142544)
There are places we use "relaxed" loads where C11 requires "consume" or
stronger. Unfortunately, compilers don't really implement "consume" so
fake it for our use in a way that avoids upsetting TSan.
AZero13 [Thu, 11 Dec 2025 21:18:52 +0000 (16:18 -0500)]
gh-142571: Check for errors before calling each syscall in `PyUnstable_CopyPerfMapFile()` (#142460)
Co-authored-by: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com> Co-authored-by: Victor Stinner <vstinner@python.org> Co-authored-by: Pablo Galindo Salgado <Pablogsal@gmail.com>
If there are many untracked tuples, the GC will run too often, resulting
in poor performance. The fix is to include untracked tuples in the
"long lived" object count. The number of frozen objects is also now
included since the free-threaded GC must scan those too.
elenril [Thu, 11 Dec 2025 14:20:53 +0000 (15:20 +0100)]
gh-79986: Add parsing for References/In-Reply-To email headers (#137201)
This is a followup to 46d88a113142b26c01c95c93846a89318ba87ffc (#13397),
which added parsing for Message-ID. Similar handling is needed for the
other two identification headers.
Karolina Surma [Wed, 10 Dec 2025 12:09:41 +0000 (13:09 +0100)]
gh-131372: Include LDVERSION and EXE in base_interpreter value (#142256)
* Include LDVERSION and EXE in base_interpreter value
In Fedora, build-details.json created and installed for python3.14t
contains "/usr/bin/python3.14" as the base_interpreter value.
Create a correct string, taking into account both LDVERSION and EXE
config variables, similarly to how it's defined in altbininstall in Makefile.
* Add news
Signed-off-by: Filipe Laíns <lains@riseup.net>
---------
Signed-off-by: Filipe Laíns <lains@riseup.net> Co-authored-by: Filipe Laíns <lains@riseup.net>
Fabian Henze [Tue, 9 Dec 2025 16:48:35 +0000 (17:48 +0100)]
gh-112527: Fix help text for required options in argparse (GH-112528)
For optional arguments with required=True, the ArgumentDefaultsHelpFormatter
would always add a " (default: None)" to the end of the help text.
Since that's a bit misleading, it is removed with this commit.
gh-142342: Fix m68k assembler operand constraints for `%fpcr` access (gh-142343)
On m68k, an fmove instruction accessing %fpcr may only move from
or to a data register or a memory operand. The constraint "g" also
permits the use of address registers, which is invalid. The correct
constraint is "dm". Beginning with GCC 15, the register allocator
picks an address register in the code which causes SIGILL during
runtime.
Co-authored-by: Michael Karcher <github@mkarcher.dialup.fu-berlin.de>
gh-140727: Restructure profiling documentation for PEP 799 (#142373)
* Add profiling module documentation structure
PEP 799 introduces a new `profiling` package that reorganizes Python's
profiling tools under a unified namespace. This commit adds the documentation
structure to match: a main entry point (profiling.rst) that helps users choose
between profilers, detailed docs for the tracing profiler (profiling-tracing.rst),
and separated pstats documentation.
The tracing profiler docs note that cProfile remains as a backward-compatible
alias, so existing code continues to work. The pstats module gets its own page
since it's used by both profiler types and deserves focused documentation.
* Add profiling.sampling documentation
The sampling profiler is new in Python 3.15 and works fundamentally differently
from the tracing profiler. It observes programs from outside by periodically
capturing stack snapshots, which means zero overhead on the profiled code. This
makes it practical for production use where you can attach to live servers.
The docs explain the key concepts (statistical vs deterministic profiling),
provide quick examples upfront, document all output formats (pstats, flamegraph,
gecko, heatmap), and cover the live TUI mode. The defaults table helps users
understand what happens without any flags.
* Wire profiling docs into the documentation tree
Add the new profiling module pages to the Debugging and Profiling toctree.
The order places the main profiling.rst entry point first, followed by the
two profiler implementations, then pstats, and finally the deprecated profile
module last.
* Convert profile.rst to deprecation stub
The pure Python profile module is deprecated in 3.15 and scheduled for removal
in 3.17. Users should migrate to profiling.tracing (or use the cProfile alias
which continues to work).
The page now focuses on helping existing users migrate: it shows the old vs new
import style, keeps the shared API reference since both modules have the same
interface, and preserves the calibration docs for anyone still using the pure
Python implementation during the transition period.
* Update CLI module references for profiling restructure
Point cProfile to profiling.tracing docs and add profiling.sampling to the
list of modules with CLI interfaces. The old profile-cli label no longer
exists after the documentation restructure.
* Update whatsnew to link to profiling module docs
Enable cross-references to the new profiling module documentation and update
the CLI examples to use the current syntax with the attach subcommand. Also
reference profiling.tracing instead of cProfile since that's the new canonical
name.
Mark Shannon [Mon, 8 Dec 2025 17:57:11 +0000 (17:57 +0000)]
GH-139757: JIT: Remove redundant branches to jumps in the assembly optimizer (GH-140800)
JIT: Remove redundant branches to jump in the assembly optimizer
* Refactor JIT assembly optimizer making instructions instances not just strings
* Remove redundant jumps and branches where legal to do so
* Modifies _BINARY_OP_SUBSCR_STR_INT to avoid excessive inlining depth
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