3.14.0a5 - Cpython — ContextQMD

.. date: 2025-02-10-22-08-37 .. gh-issue: 91132 .. nonce: 00x1MI .. release date: 2025-02-11 .. section: macOS

Update macOS installer to use ncurses 6.5.

.. date: 2025-01-24-14-49-40 .. gh-issue: 129248 .. nonce: JAapG2 .. section: Tools/Demos

The iOS test runner now strips the log prefix from each line output by the test suite.

.. date: 2023-05-11-23-32-25 .. gh-issue: 104400 .. nonce: 23vxm7 .. section: Tools/Demos

Fix several bugs in extraction by switching to an AST parser in :program:pygettext.

.. date: 2025-01-30-13-09-27 .. gh-issue: 129386 .. nonce: iNtbEi .. section: Tests

Add test.support.reset_code, which can be used to reset various bytecode-level optimizations and local instrumentation for a function.

.. date: 2025-01-04-02-41-41 .. gh-issue: 128474 .. nonce: 0b-tl4 .. section: Tests

Disable test_embed test cases that segfault on BOLT instrument binaries. The tests are only disabled when BOLT is enabled.

.. date: 2024-12-16-19-15-10 .. gh-issue: 128003 .. nonce: GVBrfa .. section: Tests

Add an option --parallel-threads=N to the regression test runner that runs individual tests in multiple threads in parallel in order to find concurrency bugs. Note that most of the test suite is not yet reviewed for thread-safety or annotated with @thread_unsafe when necessary.

.. date: 2025-01-28-14-08-03 .. gh-issue: 105704 .. nonce: EnhHxu .. section: Security

When using :func:urllib.parse.urlsplit and :func:urllib.parse.urlparse host parsing would not reject domain names containing square brackets ([ and ]). Square brackets are only valid for IPv6 and IPvFuture hosts according to RFC 3986 Section 3.2.2 <https://www.rfc-editor.org/rfc/rfc3986#section-3.2.2>__.

.. date: 2024-10-29-09-15-10 .. gh-issue: 126108 .. nonce: eTIjHY .. section: Security

Fix a possible NULL pointer dereference in :c:func:!PySys_AddWarnOptionUnicode.

.. date: 2024-08-06-11-43-08 .. gh-issue: 80222 .. nonce: wfR4BU .. section: Security

Fix bug in the folding of quoted strings when flattening an email message using a modern email policy. Previously when a quoted string was folded so that it spanned more than one line, the surrounding quotes and internal escapes would be omitted. This could theoretically be used to spoof header lines using a carefully constructed quoted string if the resulting rendered email was transmitted or re-parsed.

.. date: 2024-05-24-21-00-52 .. gh-issue: 119511 .. nonce: jKrXQ8 .. section: Security

Fix a potential denial of service in the :mod:imaplib module. When connecting to a malicious server, it could cause an arbitrary amount of memory to be allocated. On many systems this is harmless as unused virtual memory is only a mapping, but if this hit a virtual address size limit it could lead to a :exc:MemoryError or other process crash. On unusual systems or builds where all allocated memory is touched and backed by actual ram or storage it could've consumed resources doing so until similarly crashing.

.. date: 2025-02-10-14-34-34 .. gh-issue: 129939 .. nonce: B08L4e .. section: Library

Comparison pages with highlighted changes generated by the :class:difflib.HtmlDiff class now support dark mode.

.. date: 2025-02-10-08-44-11 .. gh-issue: 129928 .. nonce: QuiZEz .. section: Library

Raise :exc:sqlite3.ProgrammingError if a user-defined SQL function with invalid number of parameters is created. Patch by Erlend Aasland.

.. date: 2025-02-09-17-47-01 .. gh-issue: 129583 .. nonce: -130Ys .. section: Library

Update bundled pip to 25.0.1

.. date: 2025-02-07-10-34-09 .. gh-issue: 129766 .. nonce: 6n5fQZ .. section: Library

Fix crash in :mod:warnings, when calling _release_lock() with no existing lock.

.. date: 2025-02-05-13-19-15 .. gh-issue: 129005 .. nonce: Sb69L_ .. section: Library

_pyio.FileIO.readall() now allocates, resizes, and fills a data buffer using the same algorithm _io.FileIO.readall() uses.

.. date: 2025-02-04-15-16-33 .. gh-issue: 129646 .. nonce: sapk1F .. section: Library

Update the locale alias mapping in the :mod:locale module to match the latest X Org locale alias mapping and support new locales in Glibc 2.41.

.. date: 2025-02-03-22-31-43 .. gh-issue: 128317 .. nonce: n2Swnh .. section: Library

Put CLI calendar highlighting in private class, removing highlight_day from public :class:calendar.TextCalendar API. Patch by Hugo van Kemenade.

.. date: 2025-02-03-01-43-16 .. gh-issue: 129603 .. nonce: xge9Tx .. section: Library

Fix bugs where :class:sqlite3.Row objects could segfault if their inherited :attr:~sqlite3.Cursor.description was set to None. Patch by Erlend Aasland.

.. date: 2025-02-01-14-55-33 .. gh-issue: 129559 .. nonce: hQCeAz .. section: Library

Add :meth:bytearray.resize method so :class:bytearray can be efficiently resized in place.

.. date: 2025-01-31-11-14-05 .. gh-issue: 129502 .. nonce: j_ArNo .. section: Library

Unlikely errors in preparing arguments for :mod:ctypes callback are now handled in the same way as errors raised in the callback of in converting the result of the callback -- using :func:sys.unraisablehook instead of :func:sys.excepthook and not setting :data:sys.last_exc and other variables.

.. date: 2025-01-29-17-10-00 .. gh-issue: 129403 .. nonce: 314159 .. section: Library

Corrected :exc:ValueError message for :class:asyncio.Barrier and :class:threading.Barrier.

.. date: 2025-01-29-14-30-54 .. gh-issue: 129409 .. nonce: JZbOE6 .. section: Library

Fix an integer overflow in the :mod:csv module when writing a data field larger than 2GB.

.. date: 2025-01-29-13-37-18 .. gh-issue: 126400 .. nonce: DaBaR3 .. section: Library

Add a socket timeout keyword argument to :class:logging.handlers.SysLogHandler.

.. date: 2025-01-29-11-14-20 .. gh-issue: 118761 .. nonce: gMZwE1 .. section: Library

Always lazy import warnings in :mod:threading. Patch by Taneli Hukkinen.

.. date: 2025-01-29-10-53-32 .. gh-issue: 118761 .. nonce: i8wjpV .. section: Library

Improve import time of :mod:subprocess by lazy importing locale and signal. Patch by Taneli Hukkinen.

.. date: 2025-01-27-14-05-19 .. gh-issue: 129346 .. nonce: gZRd3g .. section: Library

In :mod:sqlite3, handle out-of-memory when creating user-defined SQL functions.

.. date: 2025-01-26-10-01-21 .. gh-issue: 129005 .. nonce: ncpLvw .. section: Library

Optimize _pyio.FileIO.readinto by avoiding unnecessary objects and copies using :func:os.readinto.

.. date: 2025-01-24-10-48-32 .. gh-issue: 129195 .. nonce: 89d5NU .. section: Library

Support reporting call graph information from :func:!asyncio.staggered.staggered_race.

.. date: 2025-01-22-16-54-25 .. gh-issue: 129205 .. nonce: FMqrUt .. section: Library

Add :func:os.readinto to read into a :ref:buffer object <bufferobjects> from a file descriptor.

.. date: 2025-01-22-13-29-06 .. gh-issue: 128772 .. nonce: 6YrxYM .. section: Library

Fix :mod:pydoc for methods with the __module__ attribute equal to None.

.. date: 2025-01-21-18-52-32 .. gh-issue: 129061 .. nonce: 4idD_B .. section: Library

Fix FORCE_COLOR and NO_COLOR when empty strings. Patch by Hugo van Kemenade.

.. date: 2025-01-20-20-59-26 .. gh-issue: 92897 .. nonce: G0xH8o .. section: Library

Scheduled the deprecation of the check_home argument of :func:sysconfig.is_python_build to Python 3.15.

.. date: 2025-01-20-16-02-38 .. gh-issue: 129064 .. nonce: JXasgJ .. section: Library

Deprecate :func:!sysconfig.expand_makefile_vars, in favor of using :func:sysconfig.get_paths with the vars argument.

.. date: 2025-01-20-13-12-39 .. gh-issue: 128550 .. nonce: AJ5TOL .. section: Library

Removed an incorrect optimization relating to eager tasks in :class:asyncio.TaskGroup that resulted in cancellations being missed.

.. date: 2025-01-18-16-58-10 .. gh-issue: 128991 .. nonce: EzJit9 .. section: Library

Release the enter frame reference within :mod:bdb callback

.. date: 2025-01-18-11-24-02 .. gh-issue: 118761 .. nonce: G8MmxY .. section: Library

Reduce import time of :mod:pstats and :mod:zipfile by up to 20%, by removing unnecessary imports to :mod:typing. Patch by Bénédikt Tran.

.. date: 2025-01-18-11-04-44 .. gh-issue: 128978 .. nonce: hwg7-w .. section: Library

Fix a :exc:NameError in :func:!sysconfig.expand_makefile_vars. Patch by Bénédikt Tran.

.. date: 2025-01-17-21-33-11 .. gh-issue: 128961 .. nonce: XwvyIZ .. section: Library

Fix a crash when setting state on an exhausted :class:array.array iterator.

.. date: 2025-01-17-17-20-51 .. gh-issue: 128894 .. nonce: gX1-8J .. section: Library

Fix traceback.TracebackException._format_syntax_error not to fail on exceptions with custom metadata.

.. date: 2025-01-17-11-46-16 .. gh-issue: 128916 .. nonce: GEePbO .. section: Library

Do not attempt to set SO_REUSEPORT on sockets of address families other than AF_INET and AF_INET6, as it is meaningless with these address families, and the call with fail with Linux kernel 6.12.9 and newer.

.. date: 2025-01-16-10-06-40 .. gh-issue: 118761 .. nonce: z100LC .. section: Library

Improve import time of :mod:tomllib by removing typing, string, and tomllib._types imports. Patch by Taneli Hukkinen.

.. date: 2025-01-15-21-41-51 .. gh-issue: 128679 .. nonce: tq10F2 .. section: Library

:mod:tracemalloc: Fix race conditions when :func:tracemalloc.stop is called by a thread, while other threads are tracing memory allocations. Patch by Victor Stinner.

.. date: 2025-01-15-19-32-23 .. gh-issue: 128891 .. nonce: ojUxKo .. section: Library

Add specialized opcodes to opcode.opname.

.. date: 2025-01-15-19-16-50 .. gh-issue: 118761 .. nonce: cbW2ZL .. section: Library

Reduce import time of :mod:gettext by up to ten times, by importing :mod:re on demand. In particular, re is no longer implicitly exposed as gettext.re. Patch by Eli Schwartz.

.. date: 2025-01-15-18-54-48 .. gh-issue: 118761 .. nonce: G1dv6E .. section: Library

Reduce the import time of :mod:optparse when no help text is printed. Patch by Eli Schwartz.

.. date: 2025-01-15-15-45-21 .. gh-issue: 128657 .. nonce: P5LNQA .. section: Library

Fix possible extra reference when using objects returned by :func:hashlib.sha256 under :term:free threading.

.. date: 2025-01-15-09-45-43 .. gh-issue: 118761 .. nonce: TvAC8E .. section: Library

Reduce the import time of :mod:csv by up to five times, by importing :mod:re on demand. In particular, re is no more implicitly exposed as csv.re. Patch by Bénédikt Tran.

.. date: 2025-01-13-07-54-32 .. gh-issue: 128308 .. nonce: kYSDRF .. section: Library

Support the name keyword argument for eager tasks in :func:asyncio.loop.create_task, :func:asyncio.create_task and :func:asyncio.TaskGroup.create_task, by passing on all kwargs to the task factory set by :func:asyncio.loop.set_task_factory.

.. date: 2025-01-10-13-06-54 .. gh-issue: 118761 .. nonce: f8oADD .. section: Library

Improve the performance of :func:base64.b16decode by up to ten times by more efficiently checking the byte-string for hexadecimal digits. Reduce the import time of :mod:base64 by up to six times, by no longer importing :mod:re. Patch by Bénédikt Tran, Chris Markiewicz, and Adam Turner.

.. date: 2025-01-09-16-20-34 .. gh-issue: 128156 .. nonce: GfObBq .. section: Library

When using macOS system libffi, support for complex types in :mod:ctypes is now checked at runtime (macOS 10.15 or newer). The types must also be available at build time.

.. date: 2025-01-08-22-30-38 .. gh-issue: 128636 .. nonce: jQfWXj .. section: Library

Fix PyREPL failure when :data:os.environ is overwritten with an invalid value.

.. date: 2025-01-07-21-48-32 .. gh-issue: 128498 .. nonce: n6jtlW .. section: Library

Default to stdout isatty for color detection instead of stderr. Patch by Hugo van Kemenade.

.. date: 2025-01-06-10-37-27 .. gh-issue: 128384 .. nonce: V0xzwH .. section: Library

Add locking to :mod:warnings to avoid some data races when free-threading is used. Change _warnings_runtime_state.mutex to be a recursive mutex and expose it to :mod:warnings, via the :func:!_acquire_lock and :func:!_release_lock functions. The lock is held when filters and _filters_version are updated.

.. date: 2025-01-04-20-51-48 .. gh-issue: 128509 .. nonce: 3gr_-O .. section: Library

Add :func:sys._is_immortal for identifying :term:immortal objects at runtime.

.. date: 2025-01-04-11-10-04 .. gh-issue: 128479 .. nonce: jvOrF- .. section: Library

Fix :func:!asyncio.staggered.staggered_race leaking tasks and issuing an unhandled exception.

.. date: 2025-01-02-20-34-04 .. gh-issue: 128427 .. nonce: onPoQZ .. section: Library

:const:uuid.NIL and :const:uuid.MAX are now available to represent the Nil and Max UUID formats as defined by :rfc:9562.

.. date: 2024-12-30-19-53-14 .. gh-issue: 91279 .. nonce: EeOJk1 .. section: Library

:meth:zipfile.ZipFile.writestr now respect SOURCE_DATE_EPOCH that distributions can set centrally and have build tools consume this in order to produce reproducible output.

.. date: 2024-12-26-11-00-03 .. gh-issue: 112064 .. nonce: mCcw3B .. section: Library

Fix incorrect handling of negative read sizes in :meth:HTTPResponse.read <http.client.HTTPResponse.read>. Patch by Yury Manushkin.

.. date: 2024-12-23-02-09-44 .. gh-issue: 58956 .. nonce: 4OdMdT .. section: Library

Fixed a frame reference leak in :mod:bdb.

.. date: 2024-12-21-03-20-12 .. gh-issue: 128131 .. nonce: QpPmNt .. section: Library

Completely support random access of uncompressed unencrypted read-only zip files obtained by :meth:ZipFile.open <zipfile.ZipFile.open>.

.. date: 2024-12-20-08-44-12 .. gh-issue: 127975 .. nonce: 8HJwu9 .. section: Library

Avoid reusing quote types in :func:ast.unparse if not needed.

.. date: 2024-12-17-16-48-02 .. gh-issue: 115514 .. nonce: 1yOJ7T .. section: Library

Fix exceptions and incomplete writes after :class:!asyncio._SelectorTransport is closed before writes are completed.

.. date: 2024-12-16-22-20-38 .. gh-issue: 121604 .. nonce: m3Xn4G .. section: Library

Add missing Deprecation warnings for :const:importlib.machinery.DEBUG_BYTECODE_SUFFIXES, :const:importlib.machinery.OPTIMIZED_BYTECODE_SUFFIXES, :class:importlib.machinery.WindowsRegistryFinder, :class:importlib.abc.ResourceLoader, :meth:importlib.abc.SourceLoader.path_mtime.

.. date: 2024-12-12-18-25-50 .. gh-issue: 127873 .. nonce: WJRwfz .. section: Library

When -E is set, only ignore PYTHON_COLORS and not FORCE_COLOR/NO_COLOR/TERM when colourising output. Patch by Hugo van Kemenade.

.. date: 2024-12-10-19-39-35 .. gh-issue: 125413 .. nonce: wOb4yr .. section: Library

Add :attr:pathlib.Path.info attribute, which stores an object implementing the :class:pathlib.types.PathInfo protocol (also new). The object supports querying the file type and internally caching :func:~os.stat results. Path objects generated by :meth:~pathlib.Path.iterdir are initialized with file type information gleaned from scanning the parent directory.

.. date: 2024-12-07-20-33-43 .. gh-issue: 127712 .. nonce: Uzsij4 .. section: Library

Fix handling of the secure argument of :class:logging.handlers.SMTPHandler.

.. date: 2024-11-24-22-06-42 .. gh-issue: 127096 .. nonce: R7LLpQ .. section: Library

Do not recreate unnamed section on every read in :class:configparser.ConfigParser. Patch by Andrey Efremov.

.. date: 2024-11-23-21-17-28 .. gh-issue: 124369 .. nonce: Z0hQFQ .. section: Library

Deprecate pdb.Pdb.curframe_locals

.. date: 2024-11-10-19-45-01 .. gh-issue: 126332 .. nonce: WCCKoH .. section: Library

Fix _pyrepl crash when entering a double CTRL-Z on an overflowing line.

.. date: 2024-10-26-16-59-02 .. gh-issue: 125553 .. nonce: 4pDLzt .. section: Library

Fix round-trip invariance for backslash continuations in :func:tokenize.untokenize.

.. date: 2024-10-02-11-17-23 .. gh-issue: 91048 .. nonce: QWY-b1 .. section: Library

Add :func:asyncio.capture_call_graph and :func:asyncio.print_call_graph functions.

.. date: 2024-09-27-19-21-53 .. gh-issue: 124703 .. nonce: lYTLEv .. section: Library

Quitting :mod:pdb in inline mode will emit a confirmation prompt and exit gracefully now, instead of printing an exception traceback.

.. date: 2024-09-12-14-24-25 .. gh-issue: 123987 .. nonce: 7_OD1p .. section: Library

Fixed issue in NamespaceReader where a non-path item in a namespace path, such as a sentinel added by an editable installer, would break resource loading.

.. date: 2024-08-12-11-58-15 .. gh-issue: 119349 .. nonce: -xTnHl .. section: Library

Add the :func:ctypes.util.dllist function to list the loaded shared libraries for the current process.

.. date: 2024-08-01-01-00-00 .. gh-issue: 55454 .. nonce: wy0vGw .. section: Library

Add IMAP4 IDLE support to the :mod:imaplib module. Patch by Forest.

.. date: 2024-07-14-23-19-20 .. gh-issue: 119257 .. nonce: 9OEzcN .. section: Library

Show tab completions menu below the current line, which results in less janky behaviour, and fixes a cursor movement bug. Patch by Daniel Hollas

.. date: 2023-02-01-16-41-31 .. gh-issue: 101410 .. nonce: Dt2aQE .. section: Library

Support custom messages for domain errors in the :mod:math module (:func:math.sqrt, :func:math.log and :func:math.atanh were modified as examples). Patch by Charlie Zhao and Sergey B Kirpichev.

.. date: 2022-05-23-21-23-29 .. gh-issue: 81340 .. nonce: D11RkZ .. section: Library

Use :func:os.copy_file_range in :func:shutil.copy, :func:shutil.copy2, and :func:shutil.copyfile functions by default. An underlying Linux system call gives filesystems an opportunity to implement the use of copy-on-write (in case of btrfs and XFS) or server-side copy (in the case of NFS.) Patch by Illia Volochii.

.. bpo: 27307 .. date: 2020-08-07-16-55-57 .. nonce: Xqzzda .. section: Library

Add attribute and item access support to :class:string.Formatter in auto-numbering mode, which allows format strings like '{.name}' and '{[1]}'.

.. date: 2025-02-08-23-42-24 .. gh-issue: 129873 .. nonce: -gofkd .. section: IDLE

Simplify displaying the IDLE doc by only copying the text section of idle.html to idlelib/help.html. Patch by Stan Ulbrych.

.. date: 2025-01-16-18-59-11 .. gh-issue: 125722 .. nonce: eHHRga .. section: Documentation

Require Sphinx 8.1.3 or later to build the Python documentation. Patch by Adam Turner.

.. date: 2025-01-14-11-06-41 .. gh-issue: 67206 .. nonce: LYKmi5 .. section: Documentation

Document that :const:string.printable is not printable in the POSIX sense. In particular, :meth:string.printable.isprintable() <str.isprintable> returns :const:False. Patch by Bénédikt Tran.

.. date: 2025-02-07-17-06-39 .. gh-issue: 100239 .. nonce: WvBTPL .. section: Core and Builtins

Replace the opcode BINARY_SUBSCR and its family by BINARY_OP with oparg NB_SUBSCR.

.. date: 2025-02-06-17-57-33 .. gh-issue: 129732 .. nonce: yl97oq .. section: Core and Builtins

Fixed a race in _Py_qsbr_reserve in the free threading build.

.. date: 2025-02-06-17-05-09 .. gh-issue: 129763 .. nonce: 6ZxQ8W .. section: Core and Builtins

Remove the internal LLTRACE macro (use :c:macro:Py_DEBUG instead).

.. date: 2025-02-05-22-58-18 .. gh-issue: 129715 .. nonce: mLlpIO .. section: Core and Builtins

Improve JIT performance for generators.

.. date: 2025-02-05-11-29-52 .. gh-issue: 129643 .. nonce: 4mGzvg .. section: Core and Builtins

Fix thread safety of :c:func:PyList_Insert in free-threading builds.

.. date: 2025-02-04-21-26-05 .. gh-issue: 129668 .. nonce: zDanyM .. section: Core and Builtins

Fix race condition when raising :exc:MemoryError in the free threaded build.

.. date: 2025-02-04-12-42-40 .. gh-issue: 129643 .. nonce: K24Zow .. section: Core and Builtins

Fix thread safety of :c:func:PyList_SetItem in free-threading builds. Patch by Kumar Aditya.

.. date: 2025-01-28-11-13-41 .. gh-issue: 128563 .. nonce: xElppE .. section: Core and Builtins

Fix an issue where the "lltrace" debug feature could have been incorrectly enabled for some frames.

.. date: 2025-01-28-10-26-04 .. gh-issue: 129393 .. nonce: 0eICq6 .. section: Core and Builtins

On FreeBSD, :data:sys.platform doesn't contain the major version anymore. It is always 'freebsd', instead of 'freebsd13' or 'freebsd14'.

.. date: 2025-01-28-06-23-59 .. gh-issue: 129345 .. nonce: uOjkML .. section: Library

Fix null pointer dereference in :func:syslog.openlog when an audit hook raises an exception.

.. date: 2025-01-24-11-37-22 .. gh-issue: 129231 .. nonce: ZsAP9v .. section: Core and Builtins

Improve memory layout of JIT traces. Patch by Diego Russo

.. date: 2025-01-22-14-24-44 .. gh-issue: 129149 .. nonce: wAYu43 .. section: Core and Builtins

Add fast path for medium-size integers in :c:func:PyLong_FromUnsignedLong, :c:func:PyLong_FromUnsignedLongLong and :c:func:PyLong_FromSize_t.

.. date: 2025-01-22-14-22-34 .. gh-issue: 129201 .. nonce: wiZzEb .. section: Core and Builtins

The free-threaded version of the cyclic garbage collector has been optimized to conditionally use CPU prefetch instructions during the collection. This can reduce collection times by making it more likely that data is in the CPU cache when it is needed. The prefetch instructions are enabled if the number of long-lived objects (objects surviving a full collection) exceeds a threshold.

.. date: 2025-01-21-23-35-41 .. gh-issue: 129093 .. nonce: 0rvETC .. section: Core and Builtins

Fix f-strings such as f'{expr=}' sometimes not displaying the full expression when the expression contains !=.

.. date: 2025-01-21-19-48-30 .. gh-issue: 124363 .. nonce: vOFhHW .. section: Core and Builtins

Treat debug expressions in f-string as raw strings. Patch by Pablo Galindo

.. date: 2025-01-19-09-07-44 .. gh-issue: 128714 .. nonce: m1fyCB .. section: Core and Builtins

Fix the potential races in get/set dunder methods __annotations__, __annotate__ and __type_params__ for function object, and add related tests.

.. date: 2025-01-18-01-06-58 .. gh-issue: 128799 .. nonce: vSNagk .. section: Core and Builtins

Add frame of except* to traceback when it wraps a naked exception.

.. date: 2025-01-17-13-16-14 .. gh-issue: 128842 .. nonce: OMs5X6 .. section: Core and Builtins

Collect JIT memory stats using pystats. Patch by Diego Russo.

.. date: 2025-01-16-22-54-12 .. gh-issue: 100239 .. nonce: 7_HpBU .. section: Core and Builtins

Specialize BINARY_OP for bitwise logical operations on compact ints.

.. date: 2025-01-16-18-16-18 .. gh-issue: 128910 .. nonce: 9pqfab .. section: Core and Builtins

Undocumented and unused private C-API functions _PyTrash_begin and _PyTrash_end are removed.

.. date: 2025-01-13-17-03-49 .. gh-issue: 128807 .. nonce: BGGBxD .. section: Core and Builtins

Add a marking phase to the free-threaded GC. This is similar to what was done in GH-126491. Since the free-threaded GC does not have generations and is not incremental, the marking phase looks for all objects reachable from known roots. The roots are objects known to not be garbage, like the module dictionary for :mod:sys. For most programs, this marking phase should make the GC a bit faster since typically less work is done per object.

.. date: 2025-01-10-23-54-16 .. gh-issue: 100239 .. nonce: ijOOUs .. section: Core and Builtins

Add opcode BINARY_OP_EXTEND which executes a pair of functions (guard and specialization functions) accessed from the inline cache.

.. date: 2025-01-10-18-56-20 .. gh-issue: 128563 .. nonce: baDvls .. section: Core and Builtins

A new type of interpreter has been added to CPython. This interpreter uses tail calls for its instruction handlers. Preliminary benchmark results suggest 7-11% geometric mean faster on pyperformance (depending on platform), and up to 30% faster on Python-intensive workloads. This interpreter currently only works on newer compilers, such as clang-19. Other compilers will continue using the old interpreter. Patch by Ken Jin, with ideas on how to implement this in CPython by Mark Shannon, Garret Gu, Haoran Xu, and Josh Haberman.

.. date: 2025-01-07-19-26-40 .. gh-issue: 126703 .. nonce: 9i-S5t .. section: Core and Builtins

Improve performance of iterating over lists and tuples by using a freelist for the iterator objects.

.. date: 2024-12-30-15-49-31 .. gh-issue: 127953 .. nonce: B4_6L9 .. section: Core and Builtins

The time to handle a LINE event in sys.monitoring (and sys.settrace) is now independent of the number of lines in the code object.

.. date: 2024-12-29-15-09-21 .. gh-issue: 128330 .. nonce: IaYL7G .. section: Core and Builtins

Restore terminal control characters on REPL exit.

.. date: 2024-12-17-09-28-17 .. gh-issue: 128016 .. nonce: DPqhah .. section: Core and Builtins

Improved the SyntaxWarning message for invalid escape sequences to clarify that such sequences will raise a SyntaxError in future Python releases. The new message also suggests a potential fix, i.e., Did you mean "\\e"?.

.. date: 2024-12-06-11-32-58 .. gh-issue: 126004 .. nonce: CYAwTB .. section: Core and Builtins

Fix handling of :attr:UnicodeError.start and :attr:UnicodeError.end values in the :func:codecs.replace_errors error handler. Patch by Bénédikt Tran.

.. date: 2024-12-06-11-30-58 .. gh-issue: 126004 .. nonce: -p8MAS .. section: Core and Builtins

Fix handling of :attr:UnicodeError.start and :attr:UnicodeError.end values in the :func:codecs.backslashreplace_errors error handler. Patch by Bénédikt Tran.

.. date: 2024-12-06-11-17-46 .. gh-issue: 126004 .. nonce: -p8MAS .. section: Core and Builtins

Fix handling of :attr:UnicodeError.start and :attr:UnicodeError.end values in the :func:codecs.xmlcharrefreplace_errors error handler. Patch by Bénédikt Tran.

.. date: 2024-12-04-22-14-40 .. gh-issue: 127119 .. nonce: _hpyFE .. section: Core and Builtins

Slightly optimize the :class:int deallocator.

.. date: 2024-11-30-16-13-31 .. gh-issue: 127349 .. nonce: ssYd6n .. section: Core and Builtins

Fixed the error when resizing terminal in Python REPL. Patch by Semyon Moroz.

.. date: 2024-11-18-12-17-45 .. gh-issue: 125723 .. nonce: tW_hFG .. section: Core and Builtins

Fix crash with gi_frame.f_locals when generator frames outlive their generator. Patch by Mikhail Efimov.

.. date: 2024-11-03-06-05-16 .. gh-issue: 126349 .. nonce: 7YwWsI .. section: Library

Add :func:turtle.fill, :func:turtle.poly and :func:turtle.no_animation context managers. Patch by Marie Roald and Yngve Mardal Moe.

.. date: 2024-02-29-16-55-52 .. gh-issue: 115911 .. nonce: Vnkue_ .. section: Core and Builtins

If the current working directory cannot be determined due to permissions, then import will no longer raise :exc:PermissionError. Patch by Alex Willmer.

.. date: 2023-12-04-15-53-25 .. gh-issue: 112713 .. nonce: Zrhv77 .. section: Library

Added support for the Partitioned cookie flag in :mod:http.cookies.

.. date: 2025-02-02-12-58-21 .. gh-issue: 129533 .. nonce: dFfqkT .. section: C API

Update :c:func:PyGC_Enable(), :c:func:PyGC_Disable(), :c:func:PyGC_IsEnabled() to use atomic operation for thread-safety at free-threading build. Patch by Donghee Na.

.. date: 2025-01-29-11-58-38 .. gh-issue: 89188 .. nonce: BsfLr3 .. section: C API

Implement :c:func:PyUnicode_KIND and :c:func:PyUnicode_DATA as function, in addition to the macros with the same names. The macros rely on C bit fields which have compiler-specific layout. Patch by Victor Stinner.

.. date: 2025-01-28-13-21-17 .. gh-issue: 91417 .. nonce: AfiR0t .. section: C API

Remove :c:func:PySequence_Fast from the limited C API, since this function has to be used with :c:macro:PySequence_Fast_GET_ITEM which never worked in the limited C API. Patch by Victor Stinner.

.. date: 2025-01-22-09-28-04 .. gh-issue: 128509 .. nonce: gqQ36L .. section: C API

Add :c:func:PyUnstable_IsImmortal for determining whether an object is :term:immortal.

.. date: 2025-01-20-10-40-11 .. gh-issue: 129033 .. nonce: d1jltB .. section: C API

Remove _PyInterpreterState_GetConfigCopy() and _PyInterpreterState_SetConfig() private functions. Use instead :c:func:PyConfig_Get and :c:func:PyConfig_Set, public C API added by :pep:741 "Python Configuration C API". Patch by Victor Stinner.

.. date: 2025-01-19-23-17-58 .. gh-issue: 129033 .. nonce: cpRivP .. section: C API

Remove the private _Py_InitializeMain() function. It was a :term:provisional API added to Python 3.8 by :pep:587. Patch by Victor Stinner.

.. date: 2025-01-16-21-56-49 .. gh-issue: 128844 .. nonce: ZPiJuo .. section: C API

Add :c:func:PyUnstable_TryIncRef and :c:func:PyUnstable_EnableTryIncRef unstable APIs. These are helpers for dealing with unowned references in a thread-safe way, particularly in the free threading build.

.. date: 2025-01-16-12-47-01 .. gh-issue: 128911 .. nonce: mHVJ4x .. section: C API

Add :c:func:PyImport_ImportModuleAttr and :c:func:PyImport_ImportModuleAttrString helper functions to import a module and get an attribute of the module. Patch by Victor Stinner.

.. date: 2025-01-15-11-42-07 .. gh-issue: 128863 .. nonce: C9MkB_ .. section: C API

The following private functions are deprecated and planned for removal in Python 3.18:

:c:func:!_PyBytes_Join: use :c:func:PyBytes_Join.
:c:func:!_PyDict_GetItemStringWithError: use :c:func:PyDict_GetItemStringRef.
:c:func:!_PyDict_Pop(): use :c:func:PyDict_Pop.
:c:func:!_PyLong_Sign(): use :c:func:PyLong_GetSign.
:c:func:!_PyLong_FromDigits and :c:func:!_PyLong_New: use :c:func:PyLongWriter_Create.
:c:func:!_PyThreadState_UncheckedGet: use :c:func:PyThreadState_GetUnchecked.
:c:func:!_PyUnicode_AsString: use :c:func:PyUnicode_AsUTF8.
:c:func:!_Py_HashPointer: use :c:func:Py_HashPointer.
:c:func:!_Py_fopen_obj: use :c:func:Py_fopen.

The pythoncapi-compat project <https://github.com/python/pythoncapi-compat/>__ can be used to get these new public functions on Python 3.13 and older.

Patch by Victor Stinner.

.. date: 2025-01-01-03-25-38 .. gh-issue: 126599 .. nonce: MRCYlH .. section: C API

Remove some internal test APIs for the experimental JIT compiler.

.. date: 2024-12-14-03-40-15 .. gh-issue: 127925 .. nonce: FF7aov .. section: C API

Convert the :mod:decimal module to use :pep:757 C API (export-import integers), offering some speed-up if the integer part of the :class:~decimal.Decimal instance is small. Patch by Sergey B Kirpichev.

.. date: 2025-02-04-12-30-43 .. gh-issue: 129660 .. nonce: SitXa7 .. section: Build

Drop test_embed from PGO training, whose contribution in recent versions is considered to be ignorable.

.. date: 2025-01-16-03-35-37 .. gh-issue: 128902 .. nonce: Dt7xtV .. section: Build

Fix compile errors with Clang 9 and older due to lack of __attribute__((fallthrough)) support.