Registro de cambios

Python next

Release date: XXXX-XX-XX

Core and Builtins

  • gh-89987: Reduce the number of inline CACHE entries for BINARY_SUBSCR.

  • gh-102859: Removed JUMP_IF_FALSE_OR_POP and JUMP_IF_TRUE_OR_POP instructions.

  • gh-101975: Fixed stacktop value on tracing entries to avoid corruption on garbage collection.

  • gh-102778: Add sys.last_exc and deprecate sys.last_type, sys.last_value and sys.last_traceback, which hold the same information in its legacy form.

  • gh-100982: Replace all occurrences of COMPARE_AND_BRANCH with COMPARE_OP.

  • gh-102701: Fix overflow when creating very large dict.

  • gh-102755: Add PyErr_DisplayException() which takes just an exception instance, to replace the legacy PyErr_Display() which takes the (typ, exc, tb) triplet.

  • gh-102594: Add note to exception raised in PyErr_SetObject when normalization fails.

  • gh-90997: Shrink the number of inline CACHE entries used by LOAD_GLOBAL.

  • gh-102491: Improve import time of platform by removing IronPython version parsing. The IronPython version parsing was not functional (see

  • gh-101291: Rearrage bits in first field (after header) of PyLongObject. * Bits 0 and 1: 1 - sign. I.e. 0 for positive numbers, 1 for zero and 2 for negative numbers. * Bit 2 reserved (probably for the immortal bit) * Bits 3+ the unsigned size.

    This makes a few operations slightly more efficient, and will enable a more compact and faster 2s-complement representation of most ints in future.

  • gh-102397: Fix segfault from race condition in signal handling during garbage collection. Patch by Kumar Aditya.

  • gh-102406: codecs encoding/decoding errors now get the context information (which operation and which codecs) attached as PEP 678 notes instead of through chaining a new instance of the exception.

  • gh-102281: Fix potential nullptr dereference and use of uninitialized memory in fileutils. Patch by Max Bachmann.

  • gh-102300: Reuse operands with refcount of 1 in float specializations of BINARY_OP.

  • gh-102213: Fix performance loss when accessing an object’s attributes with __getattr__ defined.

  • gh-102255: Improve build support for the Xbox. Patch by Max Bachmann.

  • gh-102027: Fix SSE2 and SSE3 detection in _blake2 internal module. Patch by Max Bachmann.


  • gh-103085: Pure python locale.getencoding() will not warn deprecation.

  • gh-103068: It’s no longer possible to register conditional breakpoints in Pdb that raise SyntaxError. Patch by Tian Gao.

  • gh-102549: Don’t ignore exceptions in member type creation.

  • gh-103056: Ensure final _generate_next_value_ is a staticmethod.

  • gh-103046: Display current line label correctly in dis when show_caches is False and lasti points to a CACHE entry.

  • gh-103023: It’s no longer possible to register expressions to display in Pdb that raise SyntaxError. Patch by Tian Gao.

  • gh-102947: Improve traceback when dataclasses.fields() is called on a non-dataclass. Patch by Alex Waygood

  • gh-102780: The asyncio.Timeout context manager now works reliably even when performing cleanup due to task cancellation. Previously it could raise a CancelledError instead of an TimeoutError in such cases.

  • gh-102871: Remove support for obsolete browsers from webbrowser. Removed browsers include Grail, Mosaic, Netscape, Galeon, Skipstone, Iceape, Firebird, and Firefox versions 35 and below.

  • gh-102839: Improve performance of math.log() arguments handling by removing the argument clinic.

  • gh-102828: Add the onexc arg to shutil.rmtree(), which is like onerror but expects an exception instance rather than an exc_info tuple. Deprecate onerror.

  • gh-88965: typing: Fix a bug relating to substitution in custom classes generic over a ParamSpec. Previously, if the ParamSpec was substituted with a parameters list that itself contained a TypeVar, the TypeVar in the parameters list could not be subsequently substituted. This is now fixed.

    Patch by Nikita Sobolev.

  • gh-78530: asyncio.wait() now accepts generators yielding tasks. Patch by Kumar Aditya.

  • gh-102748: asyncio.iscoroutine() now returns False for generators as asyncio does not support legacy generator-based coroutines. Patch by Kumar Aditya.

  • gh-102670: Optimized fmean(), correlation(), covariance(), and linear_regression() using the new math.sumprod() function.

  • gh-102615: Typing: Improve the repr of generic aliases for classes generic over a ParamSpec. (Use square brackets to represent a parameter list.)

  • gh-100112: asyncio.Task.get_coro() now always returns a coroutine when wrapping an awaitable object. Patch by Kumar Aditya.

  • gh-102578: Speed up setting or deleting mutable attributes on non-dataclass subclasses of frozen dataclasses. Due to the implementation of __setattr__ and __delattr__ for frozen dataclasses, this previously had a time complexity of O(n). It now has a time complexity of O(1).

  • gh-102519: Add os.listdrives(), os.listvolumes() and os.listmounts() functions on Windows for enumerating drives, volumes and mount points

  • gh-74468: Attribute name of the extracted tarfile file object now holds filename of itself rather than of the archive it is contained in. Patch by Oleg Iarygin.

  • gh-102378: Private helper method inspect._signature_strip_non_python_syntax will no longer strip / from the input string.

  • gh-79940: Add inspect.getasyncgenstate() and inspect.getasyncgenlocals(). Patch by Thomas Krennwallner.

  • gh-102103: Add module argument to dataclasses.make_dataclass() and make classes produced by it pickleable.

  • gh-102069: Fix __weakref__ descriptor generation for custom dataclasses.

  • gh-98886: Fix issues when defining dataclasses that have fields with specific underscore names that aren’t clearly reserved by dataclasses.

  • gh-101673: Fix a pdb bug where ll clears the changes to local variables.

  • gh-101313: Added -h and –help arguments to the webbrowser CLI

  • gh-100372: ssl.SSLContext.load_verify_locations() no longer incorrectly accepts some cases of trailing data when parsing DER.

  • gh-89727: Fix pathlib.Path.walk RecursionError on deep directory trees by rewriting it using iteration instead of recursion.

  • gh-100131: Added an optional delete keyword argument to tempfile.TemporaryDirectory.

  • gh-98169: Fix dataclasses.astuple() crash when collections.defaultdict is present in the attributes.

  • gh-96931: Fix incorrect results from ssl.SSLSocket.shared_ciphers()

  • gh-95495: When built against OpenSSL 3.0, the ssl module had a bug where it reported unauthenticated EOFs (i.e. without close_notify) as a clean TLS-level EOF. It now raises SSLEOFError, matching the behavior in previous versions of OpenSSL. The options attribute on SSLContext also no longer includes OP_IGNORE_UNEXPECTED_EOF by default. This option may be set to specify the previous OpenSSL 3.0 behavior.

  • gh-94684: Now uuid.uuid3() and uuid.uuid5() functions support bytes objects as their name argument.

  • gh-94440: Fix a concurrent.futures.process bug where ProcessPoolExecutor shutdown could hang after a future has been quickly submitted and canceled.

  • gh-72346: Added deprecation warning to isdst parameter of email.utils.localtime().

  • bpo-36305: Fix handling of Windows filenames that resemble drives, such as ./a:b, in pathlib.



  • gh-102980: Improve test coverage on pdb.

  • gh-102537: Adjust the error handling strategy in test_zoneinfo.TzPathTest.python_tzpath_context. Patch by Paul Ganssle.

  • gh-101377: Improved test_locale_calendar_formatweekday of calendar.


  • gh-102973: Add a dev container (along with accompanying Dockerfile) for development purposes.

  • gh-102711: Fix -Wstrict-prototypes compiler warnings.


  • gh-102690: Update webbrowser to fall back to Microsoft Edge instead of Internet Explorer.

  • gh-99726: Improves correctness of stat results for Windows, and uses faster API when available



  • gh-102013: Add a new (unstable) C-API function for iterating over GC’able objects using a callback: PyUnstable_VisitObjects.

Python 3.12.0 alpha 6

Release date: 2023-03-07


  • gh-99108: Replace builtin hashlib implementations of MD5 and SHA1 with verified ones from the HACL* project.

  • gh-101727: Updated the OpenSSL version used in Windows and macOS binary release builds to 1.1.1t to address CVE-2023-0286, CVE-2022-4303, and CVE-2022-4303 per the OpenSSL 2023-02-07 security advisory.

  • gh-99108: Replace the builtin hashlib implementations of SHA2-384 and SHA2-512 originally from LibTomCrypt with formally verified, side-channel resistant code from the HACL* project. The builtins remain a fallback only used when OpenSSL does not provide them.

  • gh-101283: subprocess.Popen now uses a safer approach to find cmd.exe when launching with shell=True. Patch by Eryk Sun, based on a patch by Oleg Iarygin.

Core and Builtins

  • gh-102493: Fix regression in semantics of normalisation in PyErr_SetObject.

  • gh-102416: Do not memoize incorrectly automatically generated loop rules in the parser. Patch by Pablo Galindo.

  • gh-102356: Fix a bug that caused a crash when deallocating deeply nested filter objects. Patch by Marta Gómez Macías.

  • gh-102336: Cleanup Windows 7 specific special handling. Patch by Max Bachmann.

  • gh-102250: Fixed a segfault occurring when the interpreter calls a __bool__ method that raises.

  • gh-102126: Fix deadlock at shutdown when clearing thread states if any finalizer tries to acquire the runtime head lock. Patch by Kumar Aditya.

  • gh-102027: Use GetCurrentProcessId on Windows when getpid is unavailable. Patch by Max Bachmann.

  • gh-102056: Fix error handling bugs in interpreter’s exception printing code, which could cause a crash on infinite recursion.

  • gh-100982: Restrict the scope of the FOR_ITER_RANGE instruction to the scope of the original FOR_ITER instruction, to allow instrumentation.

  • gh-101967: Fix possible segfault in positional_only_passed_as_keyword function, when new list created.

  • gh-101952: Fix possible segfault in BUILD_SET opcode, when new set created.

  • gh-74895: socket.getaddrinfo no longer raises OverflowError for int port values outside of the C long range. Out of range values are left up to the underlying string based C library API to report. A socket.gaierror SAI_SERVICE may occur instead, or no error at all as not all platform C libraries generate an error.

  • gh-101799: Add CALL_INTRINSIC_2 and use it instead of PREP_RERAISE_STAR.

  • gh-101857: Fix xattr support detection on Linux systems by widening the check to linux, not just glibc. This fixes support for musl.

  • gh-84783: Make the slice object hashable. Patch by Will Bradshaw and Furkan Onder.

  • gh-87849: Change the SEND instruction to leave the receiver on the stack. This allows the specialized form of SEND to skip the chain of C calls and jump directly to the RESUME in the generator or coroutine.

  • gh-101765: Fix SystemError / segmentation fault in iter __reduce__ when internal access of builtins.__dict__ keys mutates the iter object.

  • gh-101430: Update tracemalloc to handle presize of object properly. Patch by Dong-hee Na.

  • gh-101696: Invalidate type version tag in _PyStaticType_Dealloc for static types, avoiding bug where a false cache hit could crash the interpreter. Patch by Kumar Aditya.

  • gh-101632: Adds a new RETURN_CONST instruction.

  • gh-100719: Remove gi_code field from generator (and coroutine and async generator) objects as it is redundant. The frame already includes a reference to the code object.

  • gh-98627: When an interpreter is configured to check (and only then), importing an extension module will now fail when the extension does not support multiple interpreters (i.e. doesn’t implement PEP 489 multi-phase init). This does not apply to the main interpreter, nor to subinterpreters created with Py_NewInterpreter().




  • gh-102019: Fix deadlock on shutdown if test_current_{exception,frames} fails. Patch by Jacob Bower.

  • gh-85984: Utilize new «winsize» functions from termios in pty tests.

  • gh-89792: test_tools now copies up to 10x less source data to a temporary directory during the freeze test by ignoring git metadata and other artifacts. It also limits its python build parallelism based on os.cpu_count instead of hard coding it as 8 cores.


  • gh-99942: On Android, in a static build, python-config in embed mode no longer incorrectly reports a library to link to.

  • gh-99942: On Android, python.pc now correctly reports the library to link to, the same as

  • gh-100221: Fix creating install directories in make sharedinstall if they exist outside DESTDIR already.

  • gh-96821: Explicitly mark C extension modules that need defined signed integer overflow, and add a configure option --with-strict-overflow. Patch by Matthias Görgens and Shantanu Jain.


  • gh-102344: Implement winreg.QueryValue using QueryValueEx and winreg.SetValue using SetValueEx. Patch by Max Bachmann.

  • gh-101881: Handle read and write operations on non-blocking pipes properly on Windows.

  • gh-101881: Add support for the os.get_blocking() and os.set_blocking() functions on Windows.

  • gh-101849: Ensures installer will correctly upgrade existing py.exe launcher installs.

  • gh-101763: Updates copy of libffi bundled with Windows installs to 3.4.4.

  • gh-101759: Update Windows installer to SQLite 3.40.1.

  • gh-101614: Correctly handle extensions built against debug binaries that reference python3_d.dll.

  • gh-101196: The functions os.path.isdir, os.path.isfile, os.path.islink and os.path.exists are now 13% to 28% faster on Windows, by making fewer Win32 API calls.


  • gh-101759: Update macOS installer to SQLite 3.40.1.


  • gh-101907: Removes use of non-standard C++ extension in public header files.

  • gh-99293: Document that the Py_TPFLAGS_VALID_VERSION_TAG is an internal feature, should not be used, and will be removed.

  • gh-101578: Add PyErr_GetRaisedException() and PyErr_SetRaisedException() for saving and restoring the current exception. These functions return and accept a single exception object, rather than the triple arguments of the now-deprecated PyErr_Fetch() and PyErr_Restore(). This is less error prone and a bit more efficient.

    Add PyException_GetArgs() and PyException_SetArgs() as convenience functions for retrieving and modifying the args passed to the exception’s constructor.

  • gh-91744: Introduced the Unstable C API tier, marking APi that is allowed to change in minor releases without a deprecation period. See PEP 689 for details.

Python 3.12.0 alpha 5

Release date: 2023-02-07


  • gh-99108: Replace the builtin hashlib implementations of SHA2-224 and SHA2-256 originally from LibTomCrypt with formally verified, side-channel resistant code from the HACL* project. The builtins remain a fallback only used when OpenSSL does not provide them.

Core and Builtins

  • gh-92173: Fix the defs and kwdefs arguments to PyEval_EvalCodeEx() and a reference leak in that function.

  • gh-59956: The GILState API is now partially compatible with subinterpreters. Previously, PyThreadState_GET() and PyGILState_GetThisThreadState() would get out of sync, causing inconsistent behavior and crashes.

  • gh-101400: Fix wrong lineno in exception message on continue or break which are not in a loop. Patch by Dong-hee Na.

  • gh-101372: Fix is_normalized() to properly handle the UCD 3.2.0 cases. Patch by Dong-hee Na.

  • gh-101266: Fix sys.getsizeof() reporting for int subclasses.

  • gh-101291: Refactor the PyLongObject struct into a normal Python object header and a PyLongValue struct.

  • gh-101046: Fix a possible memory leak in the parser when raising MemoryError. Patch by Pablo Galindo

  • gh-101037: Fix potential memory underallocation issue for instances of int subclasses with value zero.

  • gh-100762: Record the (virtual) exception block depth in the oparg of YIELD_VALUE. Use this to avoid the expensive throw() when closing generators (and coroutines) that can be closed trivially.

  • gh-100982: Adds a new COMPARE_AND_BRANCH instruction. This is a bit more efficient when performing a comparison immediately followed by a branch, and restores the design intent of PEP 659 that specializations are local to a single instruction.

  • gh-100942: Fixed segfault in property.getter/setter/deleter that occurred when a property subclass overrode the __new__ method to return a non-property instance.

  • gh-100923: Remove the mask cache entry for the COMPARE_OP instruction and embed the mask into the oparg.

  • gh-100892: Fix race while iterating over thread states in clearing threading.local. Patch by Kumar Aditya.

  • gh-91351: Fix a case where re-entrant imports could corrupt the import deadlock detection code and cause a KeyError to be raised out of importlib/_bootstrap. In addition to the straightforward cases, this could also happen when garbage collection leads to a warning being emitted – as happens when it collects an open socket or file)

  • gh-100726: Optimize construction of range object for medium size integers.

  • gh-100712: Added option to build cpython with specialization disabled, by setting ENABLE_SPECIALIZATION=False in opcode, followed by make regen-all.

  • bpo-32780: Inter-field padding is now inserted into the PEP3118 format strings obtained from ctypes.Structure objects, reflecting their true representation in memory.


  • gh-101541: [Enum] - fix psuedo-flag creation

  • gh-101570: Upgrade pip wheel bundled with ensurepip (pip 23.0)

  • gh-101323: Fix a bug where errors where not thrown by zlib._ZlibDecompressor if encountered during decompressing.

  • gh-101317: Add ssl_shutdown_timeout parameter for asyncio.StreamWriter.start_tls().

  • gh-101326: Fix regression when passing None as second or third argument to FutureIter.throw.

  • gh-92123: Adapt the _elementtree extension module to multi-phase init (PEP 489). Patches by Erlend E. Aasland.

  • gh-100795: Avoid potential unexpected freeaddrinfo call (double free) in socket when when a libc getaddrinfo() implementation leaves garbage in an output pointer when returning an error. Original patch by Sergey G. Brester.

  • gh-101143: Remove unused references to TimerHandle in asyncio.base_events.BaseEventLoop._add_callback.

  • gh-101144: Make and zipfile.Path.read_text() also accept encoding as a positional argument. This was the behavior in Python 3.9 and earlier. 3.10 introduced a regression where supplying it as a positional argument would lead to a TypeError.

  • gh-94518: Group-related variables of _posixsubprocess module are renamed to stress that supplimentary group affinity is added to a fork, not replace the inherited ones. Patch by Oleg Iarygin.

  • gh-101015: Fix typing.get_type_hints() on '*tuple[...]' and *tuple[...]. It must not drop the Unpack part.

  • gh-101000: Add os.path.splitroot(), which splits a path into a 3-item tuple (drive, root, tail). This new function is used by pathlib to improve the performance of path construction by up to a third.

  • gh-100573: Fix a Windows asyncio bug with named pipes where a client doing os.stat() on the pipe would cause an error in the server that disabled serving future requests.

  • gh-39615: warnings.warn() now has the ability to skip stack frames based on code filename prefix rather than only a numeric stacklevel via the new skip_file_prefixes keyword argument.

  • gh-100750: pass encoding kwarg to subprocess in platform

  • gh-100160: Emit a deprecation warning in asyncio.DefaultEventLoopPolicy.get_event_loop() if there is no current event loop set and it decides to create one.

  • gh-96290: Fix handling of partial and invalid UNC drives in ntpath.splitdrive(), and in ntpath.normpath() on non-Windows systems. Paths such as “\server” and “\” are now considered by splitdrive() to contain only a drive, and consequently are not modified by normpath() on non-Windows systems. The behaviour of normpath() on Windows systems is unaffected, as native OS APIs are used. Patch by Eryk Sun, with contributions by Barney Gale.

  • gh-99952: Fix a reference undercounting issue in ctypes.Structure with from_param() results larger than a C pointer.

  • gh-67790: Add float-style formatting support for fractions.Fraction instances.

  • gh-99266: Preserve more detailed error messages in ctypes.

  • gh-86682: Ensure runtime-created collections have the correct module name using the newly added (internal) sys._getframemodulename().

  • gh-88597: uuid now has a command line interface. Try python -m uuid -h.

  • gh-60580: ctypes.wintypes.BYTE definition changed from c_byte to c_ubyte to match Windows SDK. Patch by Anatoly Techtonik and Oleg Iarygin.

  • gh-94518: _posixsubprocess now initializes all UID and GID variables using a reserved -1 value instead of a separate flag. Patch by Oleg Iarygin.

  • bpo-38941: The xml.etree.ElementTree module now emits DeprecationWarning when testing the truth value of an xml.etree.ElementTree.Element. Before, the Python implementation emitted FutureWarning, and the C implementation emitted nothing.

  • bpo-40077: Convert elementtree types to heap types. Patch by Erlend E. Aasland.

  • bpo-29847: Fix a bug where pathlib.Path accepted and ignored keyword arguments. Patch provided by Yurii Karabas.

  • gh-77772: ctypes.CDLL, ctypes.OleDLL, ctypes.WinDLL, and ctypes.PyDLL now accept path-like objects as their name argument. Patch by Robert Hoelzl.


  • gh-88324: Reword subprocess to emphasize default behavior of stdin, stdout, and stderr arguments. Remove inaccurate statement about child file handle inheritance.


  • gh-101334: test_tarfile has been updated to pass when run as a high UID.


  • gh-101282: Update BOLT configration not to use depreacted usage of --split functions. Patch by Dong-hee Na.

  • gh-101522: Allow overriding Windows dependencies versions and paths using MSBuild properties.

  • gh-77532: Minor fixes to allow building with PlatformToolset=ClangCL on Windows.

  • gh-101152: In accordance with PEP 699, the ma_version_tag field in PyDictObject is deprecated for extension modules. Accessing this field will generate a compiler warning at compile time. This field will be removed in Python 3.14.

  • gh-100340: Allows -Wno-int-conversion for wasm-sdk 17 and onwards, thus enables building WASI builds once against the latest sdk.

  • gh-101060: Conditionally add -fno-reorder-blocks-and-partition in configure. Effectively fixes --enable-bolt when using Clang, as this appears to be a GCC-only flag.

  • gh-98705: __bool__ is defined in AIX system header files which breaks the build in AIX, so undefine it.

  • gh-98636: Fix a regression in detecting gdbm_compat library for the _gdbm module build.

  • gh-96305: _aix_support now uses a simple code to get platform details rather than the now non-existent _bootsubprocess during bootstrap.


  • gh-101543: Ensure the install path in the registry is only used when the standard library hasn’t been located in any other way.

  • gh-101467: The py.exe launcher now correctly filters when only a single runtime is installed. It also correctly handles prefix matches on tags so that -3.1 does not match 3.11, but would still match 3.1-32.

  • gh-99834: Updates bundled copy of Tcl/Tk to

  • gh-101135: Restore ability to launch older 32-bit versions from the py.exe launcher when both 32-bit and 64-bit installs of the same version are available.

  • gh-82052: Fixed an issue where writing more than 32K of Unicode output to the console screen in one go can result in mojibake.

  • gh-100320: Ensures the PythonPath registry key from an install is used when launching from a different copy of Python that relies on an existing install to provide a copy of its modules and standard library.

  • gh-100247: Restores support for the py.exe launcher finding shebang commands in its configuration file using the full command name.

Python 3.12.0 alpha 4

Release date: 2023-01-10

Core and Builtins

  • gh-100776: Fix misleading default value in input()”s __text_signature__.

  • gh-99005: Remove UNARY_POSITIVE, ASYNC_GEN_WRAP and LIST_TO_TUPLE, replacing them with intrinsics.

  • gh-99005: Add new CALL_INSTRINSIC_1 instruction. Remove IMPORT_STAR, PRINT_EXPR and STOPITERATION_ERROR, replacing them with the CALL_INSTRINSIC_1 instruction.

  • gh-100288: Remove the LOAD_ATTR_METHOD_WITH_DICT specialized instruction. Stats show it is not useful.

  • gh-100720: Added _PyFrame_NumSlotsForCodeObject, which returns the number of slots needed in a frame for a given code object.

  • gh-100719: Removed the co_nplaincellvars field from the code object, as it is redundant.

  • gh-100637: Fix int.__sizeof__() calculation to include the 1 element ob_digit array for 0 and False.

  • gh-100649: Update the native_thread_id field of PyThreadState after fork.

  • gh-100126: Fix an issue where «incomplete» frames could be briefly visible to C code while other frames are being torn down, possibly resulting in corruption or hard crashes of the interpreter while running finalizers.

  • gh-87447: Fix SyntaxError on comprehension rebind checking with names that are not actually redefined.

    Now reassigning b in [(b := 1) for a, b.prop in some_iter] is allowed. Reassigning a is still disallowed as per PEP 572.

  • gh-100268: Add int.is_integer() to improve duck type compatibility between int and float.

  • gh-100425: Improve the accuracy of sum() with compensated summation.

  • gh-100374: Fix incorrect result and delay in socket.getfqdn(). Patch by Dominic Socular.

  • gh-100357: Convert vars, dir, next, getattr, and iter to argument clinic.

  • gh-100117: Improve the output of co_lines by emitting only one entry for each line range.

  • gh-90043: Handle NaNs when specializing COMPARE_OP for float values.

  • gh-100222: Redefine the _Py_CODEUNIT typedef as a union to describe its layout to the C compiler, avoiding type punning and improving clarity.

  • gh-99955: Internal compiler functions (in compile.c) now consistently return -1 on error and 0 on success.

  • gh-100188: The BINARY_SUBSCR_LIST_INT and BINARY_SUBSCR_TUPLE_INT instructions are no longer used for negative integers because those instructions always miss when encountering negative integers.

  • gh-99110: Initialize frame->previous in frameobject.c to fix a segmentation fault when accessing frames created by PyFrame_New().

  • gh-94155: Improved the hashing algorithm for code objects, mitigating some hash collisions.

  • gh-99540: None now hashes to a constant value. This is not a requirements change.

  • gh-100143: When built with --enable-pystats, stats collection is now off by default. To enable it early at startup, pass the -Xpystats flag. Stats are now always dumped, even if switched off.

  • gh-100146: Improve BUILD_LIST opcode so that it works similarly to the BUILD_TUPLE opcode, by stealing references from the stack rather than repeatedly using stack operations to set list elements. Implementation details are in a new private API _PyList_FromArraySteal().

  • gh-100110: Specialize FOR_ITER for tuples.

  • gh-100050: Honor existing errors obtained when searching for mismatching parentheses in the tokenizer. Patch by Pablo Galindo

  • gh-92216: Improve the performance of hasattr() for type objects with a missing attribute.

  • gh-99582: Freeze zipimport module into _bootstrap_python.

  • gh-99554: Pack debugging location tables more efficiently during bytecode compilation.

  • gh-98522: Add an internal version number to code objects, to give better versioning of inner functions and comprehensions, and thus better specialization of those functions. This change is invisible to both Python and C extensions.

  • gh-94603: Improve performance of list.pop for small lists.

  • gh-89051: Add ssl.OP_LEGACY_SERVER_CONNECT

  • bpo-32782: ctypes arrays of length 0 now report a correct itemsize when a memoryview is constructed from them, rather than always giving a value of 0.




  • gh-100454: Start running SSL tests with OpenSSL 3.1.0-beta1.

  • gh-100086: The Python test runner (libregrtest) now logs Python build information like «debug» vs «release» build, or LTO and PGO optimizations. Patch by Victor Stinner.

  • gh-93018: Make two tests forgiving towards host system libexpat with backported security fixes applied.


  • gh-100540: Removed the --with-system-ffi configure option; libffi must now always be supplied by the system on all non-Windows platforms. The option has had no effect on non-Darwin platforms for several releases, and in 3.11 only had the non-obvious effect of invoking pkg-config to find libffi and never setting -DUSING_APPLE_OS_LIBFFI. Now on Darwin platforms configure will first check for the OS libffi and then fall back to the same processing as other platforms if it is not found.

  • gh-88267: Avoid exporting Python symbols in linked Windows applications when the core is built as static.

  • bpo-41916: Allow override of ac_cv_cxx_thread so that cross compiled python can set -pthread for CXX.


  • gh-100180: Update Windows installer to OpenSSL 1.1.1s

  • gh-99191: Use _MSVC_LANG >= 202002L instead of less-precise _MSC_VER >=1929 to more accurately test for C++20 support in PC/_wmimodule.cpp.

  • gh-79218: Define MS_WIN64 for Mingw-w64 64bit, fix cython compilation failure.

  • gh-99941: Ensure that asyncio.Protocol.data_received() receives an immutable bytes object (as documented), instead of bytearray.

  • bpo-43984: winreg.SetValueEx() now leaves the target value untouched in the case of conversion errors. Previously, -1 would be written in case of such errors.

  • bpo-34816: hasattr(ctypes.windll, 'nonexistant') now returns False instead of raising OSError.


  • gh-100180: Update macOS installer to OpenSSL 1.1.1s

  • gh-100540: Removed obsolete dlfcn.h shim from the _ctypes extension module, which has not been necessary since Mac OS X 10.2.


  • bpo-45256: Fix a bug that caused an AttributeError to be raised in when py-locals is used without a frame.

  • gh-100342: Add missing NULL check for possible allocation failure in *args parsing in Argument Clinic.


  • gh-99947: Raising SystemError on import will now have its cause be set to the original unexpected exception.

  • gh-99240: In argument parsing, after deallocating newly allocated memory, reset its pointer to NULL.

  • gh-98724: The Py_CLEAR, Py_SETREF and Py_XSETREF macros now only evaluate their arguments once. If an argument has side effects, these side effects are no longer duplicated. Patch by Victor Stinner.

Python 3.12.0 alpha 3

Release date: 2022-12-06


  • gh-100001: python -m http.server no longer allows terminal control characters sent within a garbage request to be printed to the stderr server log.

    This is done by changing the http.server BaseHTTPRequestHandler .log_message method to replace control characters with a \xHH hex escape before printing.

  • gh-87604: Avoid publishing list of active per-interpreter audit hooks via the gc module

Core and Builtins

  • gh-99891: Fix a bug in the tokenizer that could cause infinite recursion when showing syntax warnings that happen in the first line of the source. Patch by Pablo Galindo

  • gh-91054: Add PyCode_AddWatcher() and PyCode_ClearWatcher() APIs to register callbacks to receive notification on creation and destruction of code objects.

  • gh-99729: Fix an issue that could cause frames to be visible to Python code as they are being torn down, possibly leading to memory corruption or hard crashes of the interpreter.

  • gh-99708: Fix bug where compiler crashes on an if expression with an empty body block.

  • gh-99578: Fix a reference bug in _imp.create_builtin() after the creation of the first sub-interpreter for modules builtins and sys. Patch by Victor Stinner.

  • gh-99581: Fixed a bug that was causing a buffer overflow if the tokenizer copies a line missing the newline caracter from a file that is as long as the available tokenizer buffer. Patch by Pablo galindo

  • gh-99553: Fix bug where an ExceptionGroup subclass can wrap a BaseException.

  • gh-99547: Add a function to os.path to check if a path is a junction: isjunction. Add similar functionality to pathlib.Path as is_junction.

  • gh-99370: Fix zip path for venv created from a non-installed python on POSIX platforms.

  • gh-99377: Add audit events for thread creation and clear operations.

  • gh-98686: Remove the BINARY_OP_GENERIC and COMPARE_OP_GENERIC «specializations».

  • gh-99298: Remove the remaining error paths for attribute specializations, and refuse to specialize attribute accesses on types that haven’t had PyType_Ready() called on them yet.

  • gh-99127: Allow some features of syslog to the main interpreter only. Patch by Dong-hee Na.

  • gh-91053: Optimizing interpreters and JIT compilers may need to invalidate internal metadata when functions are modified. This change adds the ability to provide a callback that will be invoked each time a function is created, modified, or destroyed.

  • gh-90994: Improve error messages when there’s a syntax error with call arguments. The following three cases are covered: - No value is assigned to a named argument, eg foo(a=). - A value is assigned to a star argument, eg foo(*args=[0]). - A value is assigned to a double-star keyword argument, eg foo(**kwarg={'a': 0}).

  • bpo-45026: Optimize the range object iterator. It is now smaller, faster iteration of ranges containing large numbers. Smaller pickles, faster unpickling.

  • bpo-31718: Raise ValueError instead of SystemError when methods of uninitialized io.IncrementalNewlineDecoder objects are called. Patch by Oren Milman.

  • bpo-38031: Fix a possible assertion failure in io.FileIO when the opener returns an invalid file descriptor.


  • gh-100001: Also escape s in the http.server BaseHTTPRequestHandler.log_message so that it is technically possible to parse the line and reconstruct what the original data was. Without this a xHH is ambiguious as to if it is a hex replacement we put in or the characters r»x» came through in the original request line.

  • gh-99957: Add frozen_default parameter to typing.dataclass_transform().

  • gh-79033: Fix asyncio.Server.wait_closed() to actually do what the docs promise – wait for all existing connections to complete, after closing the server.

  • gh-51524: Fix bug when calling trace.CoverageResults with valid infile.

  • gh-99645: Fix a bug in handling class cleanups in unittest.TestCase. Now addClassCleanup() uses separate lists for different TestCase subclasses, and doClassCleanups() only cleans up the particular class.

  • gh-99508: Fix TypeError in Lib/importlib/ while calling _imp.source_hash().

  • gh-66285: Fix asyncio to not share event loop and signal wakeupfd in forked processes. Patch by Kumar Aditya.

  • gh-97001: Release the GIL when calling termios APIs to avoid blocking threads.

  • gh-92647: Use final status of an enum to determine lookup or creation branch of functional API.

  • gh-99388: Add loop_factory parameter to to allow specifying a custom event loop factory. Patch by Kumar Aditya.

  • gh-99341: Fix ast.increment_lineno() to also cover ast.TypeIgnore when changing line numbers.

  • gh-99382: Check the number of arguments in substitution in user generics containing a TypeVarTuple and one or more TypeVar.

  • gh-99379: Fix substitution of ParamSpec followed by TypeVarTuple in generic aliases.

  • gh-99344: Fix substitution of TypeVarTuple and ParamSpec together in user generics.

  • gh-99284: Remove _use_broken_old_ctypes_structure_semantics_ old untested and undocumented hack from ctypes.

  • gh-99201: Fix IndexError when initializing the config variables on Windows if HAVE_DYNAMIC_LOADING is not set.

  • gh-99240: Fix double-free bug in Argument Clinic str_converter by extracting memory clean up to a new post_parsing section.

  • gh-64490: Fix refcount error when arguments are packed to tuple in Argument Clinic.

  • gh-99029: pathlib.PurePath.relative_to() now treats naked Windows drive paths as relative. This brings its behaviour in line with other parts of pathlib.

  • gh-98253: The implementation of the typing module is now more resilient to reference leaks in binary extension modules.

    Previously, a reference leak in a typed C API-based extension module could leak internals of the typing module, which could in turn introduce leaks in essentially any other package with typed function signatures. Although the typing package is not the original source of the problem, such non-local dependences exacerbate debugging of large-scale projects, and the implementation was therefore changed to reduce harm by providing better isolation.

  • gh-98458: Fix infinite loop in unittest when a self-referencing chained exception is raised

  • gh-93453: asyncio.get_event_loop() and many other asyncio functions like asyncio.ensure_future(), asyncio.shield() or asyncio.gather(), and also the get_event_loop() method of asyncio.BaseDefaultEventLoopPolicy now raise a RuntimeError if called when there is no running event loop and the current event loop was not set. Previously they implicitly created and set a new current event loop. DeprecationWarning is no longer emitted if there is no running event loop but the current event loop was set.

  • gh-97966: On uname_result, restored expectation that _fields and _asdict would include all six properties including processor.

  • gh-98248: Provide informative error messages in struct.pack() when its integral arguments are not in range.

  • gh-98108: zipfile.Path is now pickleable if its initialization parameters were pickleable (e.g. for file system paths).

  • gh-98098: Created packages from zipfile and test_zipfile modules, separating zipfile.Path functionality.

  • gh-82836: Fix is_private properties in the ipaddress module. Previously non-private networks ( would return True from this method; now they correctly return False.

  • gh-96828: Add an OP_ENABLE_KTLS option for enabling the use of the kernel TLS (kTLS). Patch by Illia Volochii.

  • gh-88863: To avoid apparent memory leaks when asyncio.open_connection() raises, break reference cycles generated by local exception and future instances (which has exception instance as its member var). Patch by Dong Uk, Kang.

  • gh-91078: now returns None when called on an empty tarfile.

  • bpo-47220: Document the optional callback parameter of WeakMethod. Patch by Géry Ogam.

  • bpo-44817: Ignore WinError 53 (ERROR_BAD_NETPATH), 65 (ERROR_NETWORK_ACCESS_DENIED) and 161 (ERROR_BAD_PATHNAME) when using ntpath.realpath().

  • bpo-41260: Rename the fmt parameter of the pure Python implementation of to format.

  • bpo-15999: All built-in functions now accept arguments of any type instead of just bool and int for boolean parameters.


  • gh-99931: Use sphinxext-opengraph to generate OpenGraph metadata.

  • gh-89682: Reworded docstring of the default __contains__ to clarify that it returns a bool.

  • gh-88330: Improved the description of what a resource is in importlib.resources docs.

  • gh-92892: Document that calling variadic functions with ctypes requires special care on macOS/arm64 (and possibly other platforms).

  • bpo-41825: Restructured the documentation for the os.wait* family of functions, and improved the docs for os.waitid() with more explanation of the possible argument constants.


  • gh-99892: Skip test_normalization() of test_unicodedata if it fails to download NormalizationTest.txt file from Patch by Victor Stinner.

  • gh-99934: Correct test_marsh on (32 bit) x86: test_deterministic sets was failing.

  • gh-99741: We’ve implemented multi-phase init (PEP 489/630/687) for the internal (for testing) _xxsubinterpreters module.

  • gh-99659: Optional big memory tests in test_sqlite3 now catch the correct sqlite.DataError exception type in case of too large strings and/or blobs passed.

  • gh-99593: Cover the Unicode C API with tests.

  • gh-96002: Add functional test for Argument Clinic.


  • gh-99086: Fix -Wimplicit-int, -Wstrict-prototypes, and -Wimplicit-function-declaration compiler warnings in configure checks.

  • gh-99337: Fix a compilation issue with GCC 12 on macOS.

  • gh-99289: Add a COMPILEALL_OPTS variable in Makefile to override compileall options (default: -j0) in make install. Also merged the compileall commands into a single command building .pyc files for the all optimization levels (0, 1, 2) at once. Patch by Victor Stinner.

  • gh-98872: Fix a possible fd leak in Programs/_freeze_module.c introduced in Python 3.11.

  • gh-88226: Always define TARGET_* labels in Python/ceval.c, even if USE_COMPUTED_GOTOS is disabled. This allows breakpoints to be set at those labels in (for instance) gdb.



  • gh-87235: On macOS python3 /dev/fd/9 9</path/to/ failed for any script longer than a couple of bytes.

  • gh-98940: Fix Mac/ file filter bug.


  • gh-64490: Argument Clinic varargs bugfixes

    • Fix out-of-bounds error in _PyArg_UnpackKeywordsWithVararg().

    • Fix incorrect check which allowed more than one varargs in

    • Fix miscalculation of noptargs in generated code.

    • Do not generate noptargs when there is a vararg argument and no optional argument.


  • gh-98680: PyBUF_* constants were marked as part of Limited API of Python 3.11+. These were available in 3.11.0 with Py_LIMITED_API defined for 3.11, and are necessary to use the buffer API.

  • gh-99612: Fix PyUnicode_DecodeUTF8Stateful() for ASCII-only data: *consumed was not set.

  • gh-47146: The structmember.h header is deprecated. Its non-deprecated contents are now available just by including Python.h, with a Py_ prefix added if it was missing. (Deprecated contents are T_OBJECT, T_NONE, and no-op flags.) Patch by Petr Viktorin, based on earlier work by Alexander Belopolsky and Matthias Braun.

Python 3.12.0 alpha 2

Release date: 2022-11-14


  • gh-98433: The IDNA codec decoder used on DNS hostnames by socket or asyncio related name resolution functions no longer involves a quadratic algorithm. This prevents a potential CPU denial of service if an out-of-spec excessive length hostname involving bidirectional characters were decoded. Some protocols such as urllib http 3xx redirects potentially allow for an attacker to supply such a name.

    Individual labels within an IDNA encoded DNS name will now raise an error early during IDNA decoding if they are longer than 1024 unicode characters given that each decoded DNS label must be 63 or fewer characters and the entire decoded DNS name is limited to 255. Only an application presenting a hostname or label consisting primarily of RFC 3454 section 3.1 «Nothing» characters to be removed would run into of this new limit. See also RFC 5894 section 6 and RFC 3491.

  • gh-98739: Update bundled libexpat to 2.5.0

Core and Builtins

  • gh-81057: The docs clearly say that PyImport_Inittab, PyImport_AppendInittab(), and PyImport_ExtendInittab() should not be used after Py_Initialize() has been called. We now enforce this for the two functions. Additionally, the runtime now uses an internal copy of PyImport_Inittab, to guard against modification.

  • gh-99298: Fix an issue that could potentially cause incorrect error handling for some bytecode instructions.

  • gh-99254: The compiler now removes all unused constants from code objects (except the first one, which may be a docstring).

  • gh-99205: Fix an issue that prevented PyThreadState and PyInterpreterState memory from being freed properly.

  • gh-81057: The 18 global C variables holding the state of the allocators have been moved to _PyRuntimeState. This is a strictly internal change with no change in behavior.

  • gh-99181: Fix failure in except* with unhashable exceptions.

  • gh-99204: Fix calculation of sys._base_executable when inside a POSIX virtual environment using copies of the python binary when the base installation does not provide the executable name used by the venv. Calculation will fall back to alternative names («python<MAJOR>», «python<MAJOR>.<MINOR>»).

  • gh-96055: Update faulthandler to emit an error message with the proper unexpected signal number. Patch by Dong-hee Na.

  • gh-99153: Fix location of SyntaxError for a try block with both except and except*.

  • gh-98686: Merge the adaptive opcode logic into each instruction’s unquickened variant, and merge the logic in EXTENDED_ARG_QUICK into EXTENDED_ARG. With these changes, the quickening that happens at code object creation is now only responsible for initializing warmup counters and inserting superinstructions.

  • gh-99103: Fix the error reporting positions of specialized traceback anchors when the source line contains Unicode characters.

  • gh-99139: Improve the error suggestion for NameError exceptions for instances. Now if a NameError is raised in a method and the instance has an attribute that’s exactly equal to the name in the exception, the suggestion will include self.<NAME> instead of the closest match in the method scope. Patch by Pablo Galindo

  • gh-98401: Octal escapes with value larger than 0o377 (ex: "\477"), deprecated in Python 3.11, now produce a SyntaxWarning, instead of DeprecationWarning. In a future Python version they will be eventually a SyntaxError. Patch by Victor Stinner.

  • gh-98401: A backslash-character pair that is not a valid escape sequence now generates a SyntaxWarning, instead of DeprecationWarning. For example, re.compile("\d+\.\d+") now emits a SyntaxWarning ("\d" is an invalid escape sequence), use raw strings for regular expression: re.compile(r"\d+\.\d+"). In a future Python version, SyntaxError will eventually be raised, instead of SyntaxWarning. Patch by Victor Stinner.

  • gh-96793: Handle StopIteration and StopAsyncIteration raised in generator or coroutines in the bytecode, rather than in wrapping C code.

  • gh-98931: Improve the SyntaxError error message when the user types import x from y instead of from y import x. Patch by Pablo Galindo

  • gh-98852: Fix subscription of type aliases containing bare generic types or types like TypeVar: for example tuple[A, T][int] and tuple[TypeVar, T][int], where A is a generic type, and T is a type variable.

  • gh-98925: Lower the recursion depth for marshal on WASI to support (in-development) wasmtime 2.0.

  • gh-98783: Fix multiple crashes in debug mode when str subclasses are used instead of str itself.

  • gh-98811: Use complete source locations to simplify detection of __future__ imports which are not at the beginning of the file. Also corrects the offset in the exception raised in one case, which was off by one and impeded highlighting.

  • gh-96793: Add specialization of FOR_ITER for generators. Saves multiple layers of dispatch and checking to get from the FOR_ITER instruction in the caller to the RESUME in the generator.

  • gh-98762: Fix source locations of match sub-patterns.

  • gh-98586: Added the methods PyObject_Vectorcall() and PyObject_VectorcallMethod() to the Limited API along with the auxiliary macro constant PY_VECTORCALL_ARGUMENTS_OFFSET.

    The availability of these functions enables more efficient PEP 590 vector calls from binary extension modules that avoid argument boxing/unboxing overheads.

  • gh-99257: Fix an issue where member descriptors (such as those for __slots__) could behave incorrectly or crash instead of raising a TypeError when accessed via an instance of an invalid type.

  • gh-93143: Rather than changing co_code, the interpreter will now display a RuntimeWarning and assign None to any fast locals that are left unbound after jumps or del statements executed while tracing.

  • gh-96421: When calling into Python code from C code, through PyEval_EvalFrameEx() or a related C-API function, a shim frame in inserted into the call stack. This occurs in the _PyEval_EvalFrameDefault() function. The extra frame should be invisible to all Python and most C extensions, but out-of-process profilers and debuggers need to be aware of it. These shim frames can be detected by checking frame->owner == FRAME_OWNED_BY_CSTACK.

    Extensions implementing their own interpreters using PEP 523 need to be aware of this shim frame and the changes to the semantics of RETURN_VALUE, YIELD_VALUE, and RETURN_GENERATOR, which now clear the frame.

  • gh-98415: Fix detection of MAC addresses for uuid on certain OSs. Patch by Chaim Sanders

  • gh-98686: Quicken all code objects, and specialize adaptive bytecode instructions more aggressively.

  • gh-92119: Print exception class name instead of its string representation when raising errors from ctypes calls.

  • gh-91058: ImportError raised from failed from <module> import <name> now include suggestions for the value of <name> based on the available names in <module>. Patch by Pablo Galindo

  • gh-96793: The FOR_ITER now leaves the iterator on the stack on termination of the loop. This is to assist specialization of loops for generators.

  • gh-90716: Add module. It includes asymptotically faster algorithms that can be used for operations on integers with many digits. It is used by longobject.c to speed up some operations.

  • gh-95389: Expose ETH_P_ALL and some of the ETHERTYPE_* constants in socket. Patch by Noam Cohen.

  • gh-93696: Allow pdb to locate source for frozen modules in the standard library.


  • gh-99418: Fix bug in urllib.parse.urlparse() that causes URL schemes that begin with a digit, a plus sign, or a minus sign to be parsed incorrectly.

  • gh-94597: Deprecate asyncio.AbstractChildWatcher to be removed in Python 3.14. Patch by Kumar Aditya.

  • gh-99305: Improve performance of secrets.token_hex().

  • gh-74044: Fixed bug where inspect.signature() reported incorrect arguments for decorated methods.

  • gh-99275: Fix SystemError in ctypes when exception was not set during __initsubclass__.

  • gh-99277: Remove older version of _SSLProtocolTransport.get_write_buffer_limits in asyncio.sslproto

  • gh-99248: fix negative numbers failing in verify()

  • gh-99155: Fix statistics.NormalDist pickle with 0 and 1 protocols.

  • gh-93464: is now correctly activated when combined with other assignment values. E.g. ONE = auto(), 'some text' will now evaluate as (1, 'some text').

  • gh-99134: Update the bundled copy of pip to version 22.3.1.

  • gh-92584: Remove the distutils package. It was deprecated in Python 3.10 by PEP 632 «Deprecate distutils module». For projects still using distutils and cannot be updated to something else, the setuptools project can be installed: it still provides distutils. Patch by Victor Stinner.

  • gh-98999: Now _pyio is consistent with _io in raising ValueError when executing methods over closed buffers.

  • gh-83004: Clean up refleak on failed module initialisation in _zoneinfo

  • gh-83004: Clean up refleaks on failed module initialisation in _pickle

  • gh-83004: Clean up refleak on failed module initialisation in _io.

  • gh-98897: Fix memory leak in math.dist() when both points don’t have the same dimension. Patch by Kumar Aditya.

  • gh-98878: Use the frame bound builtins when offering a name suggestion in traceback to prevent crashing when __builtins__ is not a dict.

  • gh-98139: In importlib._bootstrap, enhance namespace package repr to <module 'x' (namespace) from ['path']>.

  • gh-90352: Fix _SelectorDatagramTransport to inherit from DatagramTransport in asyncio. Patch by Kumar Aditya.

  • gh-98793: Fix argument typechecks in _overlapped.WSAConnect() and _overlapped.Overlapped.WSASendTo() functions.

  • gh-98744: Prevent crashing in traceback when retrieving the byte-offset for some source files that contain certain unicode characters.

  • gh-98740: Fix internal error in the re module which in very rare circumstances prevented compilation of a regular expression containing a conditional expression without the «else» branch.

  • gh-98703: Fix asyncio.StreamWriter.drain() to call protocol.connection_lost callback only once on Windows.

  • gh-98624: Add a mutex to unittest.mock.NonCallableMock to protect concurrent access to mock attributes.

  • gh-98658: The array.array class now supports subscripting, making it a generic type.

  • gh-98284: Improved TypeError message for undefined abstract methods of a abc.ABC instance. The names of the missing methods are surrounded by single-quotes to highlight them.

  • gh-96151: Allow BUILTINS to be a valid field name for frozen dataclasses.

  • gh-98086: Make sure patch.dict() can be applied on async functions.

  • gh-72719: Remove modules asyncore and asynchat, which were deprecated by PEP 594.

  • gh-96192: Fix handling of bytes path-like objects in os.ismount().

  • gh-94172: ftplib: Remove the FTP_TLS.ssl_version class attribute: use the context parameter instead. Patch by Victor Stinner

  • gh-94172: Remove the keyfile and certfile parameters from the ftplib, imaplib, poplib and smtplib modules, and the key_file, cert_file and check_hostname parameters from the http.client module, all deprecated since Python 3.6. Use the context parameter (ssl_context in imaplib) instead. Patch by Victor Stinner.

  • gh-83638: Add the autocommit attribute to sqlite3.Connection and the autocommit parameter to sqlite3.connect() to control PEP 249-compliant transaction handling. Patch by Erlend E. Aasland.

  • gh-92452: Fixed a race condition that could cause sysconfig.get_config_var() to incorrectly return None in multi-threaded programs.

  • gh-91803: Fix an error when using a method of objects mocked with unittest.mock.create_autospec() after it was sealed with unittest.mock.seal() function.

  • bpo-38523: shutil.copytree() now applies the ignore_dangling_symlinks argument recursively.

  • bpo-40358: Add walk_up argument in pathlib.PurePath.relative_to().

  • bpo-36267: Fix IndexError in argparse.ArgumentParser when a store_true action is given an explicit argument.


  • gh-98832: Changes wording of docstring for pathlib.Path.iterdir().

  • gh-97966: Update uname docs to clarify the special nature of the platform attribute and to indicate when it became late-bound.


  • gh-98903: The Python test suite now fails wit exit code 4 if no tests ran. It should help detecting typos in test names and test methods.

  • gh-98713: Fix a bug in the typing tests where a test relying on CPython-specific implementation details was not decorated with @cpython_only and was not skipped on other implementations.

  • gh-87390: Add tests for star-unpacking with PEP 646, and some other miscellaneous PEP 646 tests.

  • gh-96853: Added explicit coverage of Py_Initialize (and hence Py_InitializeEx) back to the embedding tests (all other embedding tests migrated to Py_InitializeFromConfig in Python 3.11)

  • bpo-34272: Some C API tests were moved into the new Lib/test/test_capi/ directory.


  • gh-99086: Fix -Wimplicit-int compiler warning in configure check for PTHREAD_SCOPE_SYSTEM.

  • gh-99016: Fix build with PYTHON_FOR_REGEN=python3.8.

  • gh-97731: Specify the full path to the source location for make docclean (needed for cross-builds).

  • gh-98949: Drop unused build dependency on readelf.

  • gh-98989: Use python3.11, if available, for regeneration and freezing.

  • gh-98831: Add new tooling, in Tools/cases_generator, to generate the interpreter switch statement from a list of opcode definitions. This only affects adding, modifying or removing instruction definitions. The instruction definitions now live in Python/bytecodes.c, in the form of a custom DSL (under development). The tooling reads this file and writes Python/generated_cases.c.h, which is then included by Python/ceval.c to provide most of the cases of the main interpreter switch.

  • gh-98817: Remove PCbuild/lib.pyproj: it’s not used for anything, is only a minor convenience for Visual Studio users (who probably mostly don’t even know about it), and it takes a lot of maintenance effort to keep updated.

  • gh-98776: Fix make regen-test-levenshtein for out-of-tree builds.

  • gh-98707: Don’t use vendored libmpdec headers if --with-system-libmpdec is passed to configure. Don’t use vendored libexpat headers if --with-system-expat is passed to configure.


  • gh-98689: Update Windows builds to zlib v1.2.13. v1.2.12 has CVE-2022-37434, but the vulnerable inflateGetHeader API is not used by Python.

  • gh-98790: Assumes that a missing DLLs directory means that standard extension modules are in the executable’s directory.

  • gh-98745: Update py.exe launcher to install 3.11 by default and 3.12 on request.

  • gh-98692: Fix the Lanzador de Python para Windows ignoring unrecognized shebang lines instead of treating them as local paths

  • gh-94328: Update Windows installer to use SQLite 3.39.4.


  • gh-94328: Update macOS installer to SQLite 3.39.4.


  • gh-98724: The Py_CLEAR, Py_SETREF and Py_XSETREF macros now only evaluate their argument once. If the argument has side effects, these side effects are no longer duplicated. Patch by Victor Stinner.

  • gh-98978: Fix use-after-free in Py_SetPythonHome(NULL), Py_SetProgramName(NULL) and _Py_SetProgramFullPath(NULL) function calls. Issue reported by Benedikt Reinartz. Patch by Victor Stinner.

  • gh-98410: Add getbufferproc and releasebufferproc to the stable API.

  • gh-98610: Some configurable capabilities of sub-interpreters have changed. They always allow subprocesses (subprocess) now, whereas before subprocesses could be optionally disallowed for a sub-interpreter. Instead os.exec() can now be disallowed. Disallowing daemon threads is now supported. Disallowing all threads is still allowed, but is never done by default. Note that the optional restrictions are only available through _Py_NewInterpreterFromConfig(), which isn’t a public API. They do not affect the main interpreter, nor Py_NewInterpreter().

  • gh-98608: A _PyInterpreterConfig has been added and _Py_NewInterpreter() has been renamed to _Py_NewInterpreterFromConfig(). The «isolated_subinterpreters» argument is now a granular config that captures the previous behavior. Note that this is all «private» API.

  • gh-96853: Py_InitializeEx now correctly calls PyConfig_Clear after initializing the interpreter (the omission didn’t cause a memory leak only because none of the dynamically allocated config fields are populated by the wrapper function)

  • gh-91248: Add PyFrame_GetVar() and PyFrame_GetVarString() functions to get a frame variable by its name. Patch by Victor Stinner.

Python 3.12.0 alpha 1

Release date: 2022-10-25


  • gh-97616: Fix multiplying a list by an integer (list *= int): detect the integer overflow when the new allocated length is close to the maximum size. Issue reported by Jordan Limor. Patch by Victor Stinner.

  • gh-97514: On Linux the multiprocessing module returns to using filesystem backed unix domain sockets for communication with the forkserver process instead of the Linux abstract socket namespace. Only code that chooses to use the «forkserver» start method is affected.

    Abstract sockets have no permissions and could allow any user on the system in the same network namespace (often the whole system) to inject code into the multiprocessing forkserver process. This was a potential privilege escalation. Filesystem based socket permissions restrict this to the forkserver process user as was the default in Python 3.8 and earlier.

    This prevents Linux CVE-2022-42919.

  • gh-87389: http.server: Fix an open redirection vulnerability in the HTTP server when an URI path starts with //. Vulnerability discovered, and initial fix proposed, by Hamza Avvan.

  • gh-79096: LWPCookieJar and MozillaCookieJar create files with file mode 600 instead of 644 (Microsoft Windows is not affected)

  • gh-92888: Fix memoryview use after free when accessing the backing buffer in certain cases.

  • gh-68966: The deprecated mailcap module now refuses to inject unsafe text (filenames, MIME types, parameters) into shell commands. Instead of using such text, it will warn and act as if a match was not found (or for test commands, as if the test failed).

Core and Builtins

  • gh-98374: Suppress ImportError for invalid query for help() command. Patch by Dong-hee Na.

  • gh-98461: Fix source location in bytecode for list, set and dict comprehensions as well as generator expressions.

  • gh-98354: Added unicode check for name attribute of spec argument passed in _imp.create_builtin() function.

  • gh-98398: Fix source location of “assert” bytecodes.

  • gh-98390: Fix location of sub-expressions of boolean expressions, by reducing their scope to that of the sub-expression.

  • gh-98254: Modules from the standard library are now potentially suggested as part of the error messages displayed by the interpreter when an NameError is raised to the top level. Patch by Pablo Galindo

  • gh-97997: Add running column offset to the tokenizer state to avoid calculating AST column information with pointer arithmetic.

  • gh-97973: Modify the tokenizer to return all necessary information the parser needs to set location information in the AST nodes, so that the parser does not have to calculate those doing pointer arithmetic.

  • gh-96078: os.sched_yield() now release the GIL while calling sched_yield(2). Patch by Dong-hee Na.

  • gh-97955: Migrate zoneinfo to Argument Clinic.

  • gh-97912: The compiler now avoids quadratic behavior when finding which instructions should use the LOAD_FAST_CHECK opcode.

  • gh-97002: Fix an issue where several frame objects could be backed by the same interpreter frame, possibly leading to corrupted memory and hard crashes of the interpreter.

  • gh-97943: Bugfix: PyFunction_GetAnnotations() should return a borrowed reference. It was returning a new reference.

  • gh-97922: The Garbage Collector now runs only on the eval breaker mechanism of the Python bytecode evaluation loop instead on object allocations. The GC can also run when PyErr_CheckSignals() is called so C extensions that need to run for a long time without executing any Python code also have a chance to execute the GC periodically.

  • gh-65961: When __package__ is different than __spec__.parent, raise a DeprecationWarning instead of ImportWarning.

    Also remove importlib.util.set_package() which was scheduled for removal.

  • gh-97850: Long deprecated, module_repr() should now be completely eradicated.

  • gh-86298: In cases where warnings.warn_explicit() consults the module’s loader, an DeprecationWarning is issued when m.__loader__ differs from m.__spec__.loader.

  • gh-97779: Ensure that all Python frame objects are backed by «complete» frames.

  • gh-91052: Add API for subscribing to modification events on selected dictionaries.

  • gh-97752: Fix possible data corruption or crashes when accessing the f_back member of newly-created generator or coroutine frames.

  • gh-97591: Fixed a missing incref/decref pair in Exception.__setstate__(). Patch by Ofey Chan.

  • gh-97670: Remove the sys.getdxp() function and the Tools/scripts/ script. DXP stands for «dynamic execution pairs». They were related to DYNAMIC_EXECUTION_PROFILE and DXPAIRS macros which have been removed in Python 3.11. Python can now be built with ./configure --enable-pystats to gather statistics on Python opcodes. Patch by Victor Stinner.

  • gh-94526: Fix the Python path configuration used to initialized sys.path at Python startup. Paths are no longer encoded to UTF-8/strict to avoid encoding errors if it contains surrogate characters (bytes paths are decoded with the surrogateescape error handler). Patch by Victor Stinner.

  • gh-96670: The parser now raises SyntaxError when parsing source code containing null bytes. Patch by Pablo Galindo

  • gh-96975: Fix a crash occurring when PyEval_GetFrame() is called while the topmost Python frame is in a partially-initialized state.

  • gh-96848: Fix command line parsing: reject -X int_max_str_digits option with no value (invalid) when the PYTHONINTMAXSTRDIGITS environment variable is set to a valid limit. Patch by Victor Stinner.

  • gh-95921: Fix overly-broad source position information for chained comparisons used as branching conditions.

  • gh-96821: Fix undefined behaviour in audioop.c.

  • gh-96821: Fix undefined behaviour in _testcapimodule.c.

  • gh-95778: When ValueError is raised if an integer is larger than the limit, mention the sys.set_int_max_str_digits() function in the error message. Patch by Victor Stinner.

  • gh-96387: At Python exit, sometimes a thread holding the GIL can wait forever for a thread (usually a daemon thread) which requested to drop the GIL, whereas the thread already exited. To fix the race condition, the thread which requested the GIL drop now resets its request before exiting. Issue discovered and analyzed by Mingliang ZHAO. Patch by Victor Stinner.

  • gh-96864: Fix a possible assertion failure, fatal error, or SystemError if a line tracing event raises an exception while opcode tracing is enabled.

  • gh-95778: The PyLong_FromString function was refactored to make it more maintainable and extensible.

  • gh-96678: Fix undefined behaviour in C code of null pointer arithmetic.

  • gh-96754: Make sure that all frame objects created are created from valid interpreter frames. Prevents the possibility of invalid frames in backtraces and signal handlers.

  • gh-90997: Improve the performance of reading and writing inline bytecode caches on some platforms.

  • gh-96751: Remove dead code from CALL_FUNCTION_EX opcode.

  • gh-90751: memoryview now supports half-floats. Patch by Dong-hee Na and Antoine Pitrou.

  • gh-96678: Fix case of undefined behavior in ceval.c

  • gh-64373: Convert _functools to argument clinic.

  • gh-96641: Do not expose KeyWrapper in _functools.

  • gh-96636: Ensure that tracing, sys.setrace(), is turned on immediately. In pre-release versions of 3.11, some tracing events might have been lost when turning on tracing in a __del__ method or interrupt.

  • gh-96572: Fix use after free in trace refs build mode. Patch by Kumar Aditya.

  • gh-96611: When loading a file with invalid UTF-8 inside a multi-line string, a correct SyntaxError is emitted.

  • gh-96612: Make sure that incomplete frames do not show up in tracemalloc traces.

  • gh-90230: Fix compiler warnings and test failures when building with --enable-pystats.

  • gh-96587: Correctly raise SyntaxError on exception groups (PEP 654) on python versions prior to 3.11

  • gh-96569: Remove two cases of undefined behavoir, by adding NULL checks.

  • gh-96582: Fix possible NULL pointer dereference in _PyThread_CurrentFrames. Patch by Kumar Aditya.

  • gh-91079: Separate Python recursion checking from C recursion checking which reduces the chance of C stack overflow and allows the recursion limit to be increased safely.

  • gh-93911: Fix an issue that could prevent LOAD_ATTR from specializing properly when accessing properties.

  • gh-96348: Emit a DeprecationWarning when throw(), throw() or athrow() are called with more than one argument.

  • gh-95196: Disable incorrect pickling of the C implemented classmethod descriptors.

  • gh-96364: Fix text signatures of list.__getitem__ and dict.__getitem__.

  • gh-96352: Fix AttributeError missing name and obj attributes in object.__getattribute__(). Patch by Philip Georgi.

  • gh-93554: Change the jump opcodes so that all conditional jumps are forward jumps. Backward jumps are converted by the assembler into a conditional forward jump whose target is the fallthrough block (and with a reversed condition), followed by an unconditional backward jump. For example:



    The corresponding opcodes without direction are no longer pseudo-instructions, and they implement the forward conditional jumps.

  • gh-96268: Loading a file with invalid UTF-8 will now report the broken character at the correct location.

  • gh-96237: The internal field _PyInterpreterFrame.f_func is renamed to _PyInterpreterFrame.f_funcobj and may be any object. The f_globals and f_builtin fields may hold junk values.

    It is safest to treat the _PyInterpreterFrame struct as opaque.

  • gh-96187: Fixed a bug that caused _PyCode_GetExtra to return garbage for negative indexes. Patch by Pablo Galindo

  • gh-96143: Add a new -X perf Python command line option as well as sys.activate_stack_trampoline() and sys.deactivate_stack_trampoline() function in the sys module that allows to set/unset the interpreter in a way that the Linux perf profiler can detect Python calls. The new sys.is_stack_trampoline_active() function allows to query the state of the perf trampoline. Design by Pablo Galindo. Patch by Pablo Galindo and Christian Heimes with contributions from Gregory P. Smith [Google] and Mark Shannon.

  • gh-96071: Fix a deadlock in PyGILState_Ensure() when allocating new thread state. Patch by Kumar Aditya.

  • gh-96046: PyType_Ready() now initializes ht_cached_keys and performs additional checks to ensure that type objects are properly configured. This avoids crashes in 3rd party packages that don’t use regular API to create new types.

  • gh-96005: On WASI ENOTCAPABLE is now mapped to PermissionError. The errno modules exposes the new error number. now ignores PermissionError when it cannot open landmark files pybuilddir.txt and pyenv.cfg.

  • gh-93678: Added test a harness for direct unit tests of the compiler’s optimization stage. The _testinternalcapi.optimize_cfg() function runs the optimiser on a sequence of instructions. The CfgOptimizationTestCase class in has utilities for invoking the optimizer and checking the output.

  • gh-95245: Reduces the size of a «simple» Python object from 8 to 6 words by moving the weakreflist pointer into the pre-header directly before the object’s dict/values pointer.

  • gh-90997: Compile virtual try/except blocks to handle exceptions raised during close() or throw() calls through a suspended frame.

  • gh-95977: Optimized calling __get__() with vectorcall. Patch by Kumar Aditya.

  • gh-91210: Improve error message when a parameter without a default value follows one with a default value, and show the same message, even when the non-default/default sequence is preceded by positional-only parameters.

  • gh-95922: Fixed bug where the compiler’s eliminate_empty_basic_blocks function ignores the last block of the code unit.

  • gh-95818: Skip over incomplete frames in PyThreadState_GetFrame().

  • gh-95876: Fix format string in _PyPegen_raise_error_known_location that can lead to memory corruption on some 64bit systems. The function was building a tuple with i (int) instead of n (Py_ssize_t) for Py_ssize_t arguments.

  • gh-95605: Fix misleading contents of error message when converting an all-whitespace string to float.

  • gh-95150: Update code object hashing and equality to consider all debugging and exception handling tables. This fixes an issue where certain non-identical code objects could be «deduplicated» during compilation.

  • gh-91146: Reduce allocation size of list from str.split() and str.rsplit(). Patch by Dong-hee Na and Inada Naoki.

  • gh-87092: Create a “jump target label” abstraction in the compiler so that the compiler’s codegen stage does not work directly with basic blocks. This prepares the code for changes to the underlying CFG generation mechanism.

  • gh-95355: _PyPegen_Parser_New now properly detects token memory allocation errors. Patch by Honglin Zhu.

  • gh-90081: Run Python code in tracer/profiler function at full speed. Fixes slowdown in earlier versions of 3.11.

  • gh-95324: Emit a warning in debug mode if an object does not call PyObject_GC_UnTrack() before deallocation. Patch by Pablo Galindo.

  • gh-95245: Merge managed dict and values pointer into a single tagged pointer to save one word in the pre-header.

  • gh-93678: Add cfg_builder struct and refactor the relevant code so that a cfg can be constructed without an instance of the compiler struct.

  • gh-95185: Prevented crashes in the AST constructor when compiling some absurdly long expressions like "+0"*1000000. RecursionError is now raised instead. Patch by Pablo Galindo

  • gh-93351: ast.AST node positions are now validated when provided to compile() and other related functions. If invalid positions are detected, a ValueError will be raised.

  • gh-94438: Fix an issue that caused extended opcode arguments and some conditional pops to be ignored when calculating valid jump targets for assignments to the f_lineno attribute of frame objects. In some cases, this could cause inconsistent internal state, resulting in a hard crash of the interpreter.

  • gh-95060: Undocumented PyCode_Addr2Location function now properly returns when addrq argument is less than zero.

  • gh-95113: Replace all EXTENDED_ARG_QUICK instructions with basic EXTENDED_ARG instructions in unquickened code. Consumers of non-adaptive bytecode should be able to handle extended arguments the same way they were handled in CPython 3.10 and older.

  • gh-91409: Fix incorrect source location info caused by certain optimizations in the bytecode compiler.

  • gh-95023: Implement os.setns() and os.unshare() for Linux. Patch by Noam Cohen.

  • gh-94036: Fix incorrect source location info for some multi-line attribute accesses and method calls.

  • gh-94938: Fix error detection in some builtin functions when keyword argument name is an instance of a str subclass with overloaded __eq__ and __hash__. Previously it could cause SystemError or other undesired behavior.

  • gh-94996: ast.parse() will no longer parse function definitions with positional-only params when passed feature_version less than (3, 8). Patch by Shantanu Jain.

  • gh-94739: Allow jumping within, out of, and across exception handlers in the debugger.

  • gh-94949: ast.parse() will no longer parse parenthesized context managers when passed feature_version less than (3, 9). Patch by Shantanu Jain.

  • gh-94947: ast.parse() will no longer parse assignment expressions when passed feature_version less than (3, 8). Patch by Shantanu Jain.

  • gh-91256: Ensures the program name is known for help text during interpreter startup.

  • gh-94869: Fix the column offsets for some expressions in multi-line f-strings ast nodes. Patch by Pablo Galindo.

  • gh-94893: Fix an issue where frame object manipulations could corrupt inline bytecode caches.

  • gh-94822: Fix an issue where lookups of metaclass descriptors may be ignored when an identically-named attribute also exists on the class itself.

  • gh-91153: Fix an issue where a bytearray item assignment could crash if it’s resized by the new value’s __index__() method.

  • gh-90699: Fix reference counting bug in bool.__repr__(). Patch by Kumar Aditya.

  • gh-94694: Fix an issue that could cause code with multi-line method lookups to have misleading or incorrect column offset information. In some cases (when compiling a hand-built AST) this could have resulted in a hard crash of the interpreter.

  • gh-93252: Fix an issue that caused internal frames to outlive failed Python function calls, possibly resulting in memory leaks or hard interpreter crashes.

  • gh-94215: Fix an issue where exceptions raised by line-tracing events would cause frames to be left in an invalid state, possibly resulting in a hard crash of the interpreter.

  • gh-92228: Disable the compiler’s inline-small-exit-blocks optimization for exit blocks that are associated with source code lines. This fixes a bug where the debugger cannot tell where an exception handler ends and the following code block begins.

  • gh-94485: Line number of a module’s RESUME instruction is set to 0 as specified in PEP 626.

  • gh-94438: Account for instructions that can push NULL to the stack when setting line number in a frame. Prevents some (unlikely) crashes.

  • gh-91719: Reload opcode when raising unknown opcode error in the interpreter main loop, for C compilers to generate dispatching code independently.

  • gh-94329: Compile and run code with unpacking of extremely large sequences (1000s of elements). Such code failed to compile. It now compiles and runs correctly.

  • gh-94360: Fixed a tokenizer crash when reading encoded files with syntax errors from stdin with non utf-8 encoded text. Patch by Pablo Galindo

  • gh-88116: Fix an issue when reading line numbers from code objects if the encoded line numbers are close to INT_MIN. Patch by Pablo Galindo

  • gh-94262: Don’t create frame objects for incomplete frames. Prevents the creation of generators and closures from being observable to Python and C extensions, restoring the behavior of 3.10 and earlier.

  • gh-94192: Fix error for dictionary literals with invalid expression as value.

  • gh-87995: types.MappingProxyType instances are now hashable if the underlying mapping is hashable.

  • gh-93883: Revise the display strategy of traceback enhanced error locations. The indicators are only shown when the location doesn’t span the whole line.

  • gh-94163: Add BINARY_SLICE and STORE_SLICE instructions for more efficient handling and better specialization of slicing operations, where the slice is explicit in the source code.

  • gh-94021: Fix unreachable code warning in Python/specialize.c.

  • gh-93911: Specialize LOAD_ATTR for objects with custom __getattribute__.

  • gh-93955: Improve performance of attribute lookups on objects with custom __getattribute__ and __getattr__. Patch by Ken Jin.

  • gh-93911: Specialize LOAD_ATTR for property() attributes.

  • gh-93678: Refactor compiler optimisation code so that it no longer needs the struct assembler and struct compiler passed around. Instead, each function takes the CFG and other data that it actually needs. This will make it possible to test this code directly.

  • gh-93841: When built with -enable-pystats, sys._stats_on(), sys._stats_off(), sys._stats_clear() and sys._stats_dump() functions have been added to enable gathering stats for parts of programs.

  • gh-93516: Store offset of first traceable instruction in code object to avoid having to recompute it for each instruction when tracing.

  • gh-93516: Lazily create a table mapping bytecode offsets to line numbers to speed up calculation of line numbers when tracing.

  • gh-89828: types.GenericAlias no longer relays the __class__ attribute. For example, isinstance(list[int], type) no longer returns True.

  • gh-93678: Refactor the compiler to reduce boilerplate and repetition.

  • gh-93671: Fix some exponential backtrace case happening with deeply nested sequence patterns in match statements. Patch by Pablo Galindo

  • gh-93662: Make sure that the end column offsets are correct in multi-line method calls. Previously, the end column could precede the column offset.

  • gh-93461: importlib.invalidate_caches() now drops entries from sys.path_importer_cache with a relative path as name. This solves a caching issue when a process changes its current working directory.

    FileFinder no longer inserts a dot in the path, e.g. /egg/./spam is now /egg/spam.

  • gh-93621: Change order of bytecode instructions emitted for with and async with to reduce the number of entries in the exception table.

  • gh-93533: Reduce the size of the inline cache for LOAD_METHOD by 2 bytes.

  • gh-93444: Removed redundant fields from the compiler’s basicblock struct: b_nofallthrough, b_exit, b_return. They can be easily calculated from the opcode of the last instruction of the block.

  • gh-93429: LOAD_METHOD instruction has been removed. It was merged back into LOAD_ATTR.

  • gh-93418: Fixed an assert where an f-string has an equal sign “=” following an expression, but there’s no trailing brace. For example, f»{i=».

  • gh-93382: Cache the result of PyCode_GetCode() function to restore the O(1) lookup of the co_code attribute.

  • gh-93359: Ensure that custom ast nodes without explicit end positions can be compiled. Patch by Pablo Galindo.

  • gh-93356: Code for exception handlers is emitted at the end of the code unit’s bytecode. This avoids one jump when no exception is raised.

  • gh-93354: Use exponential backoff for specialization counters in the interpreter. Can reduce the number of failed specializations significantly and avoid slowdown for those parts of a program that are not suitable for specialization.

  • gh-93283: Improve error message for invalid syntax of conversion character in f-string expressions.

  • gh-93345: Fix a crash in substitution of a TypeVar in nested generic alias after TypeVarTuple.

  • gh-93223: When a bytecode instruction jumps to an unconditional jump instruction, the first instruction can often be optimized to target the unconditional jump’s target directly. For tracing reasons, this would previously only occur if both instructions have the same line number. This also now occurs if the unconditional jump is artificial, i.e., if it has no associated line number.

  • gh-84694: The --experimental-isolated-subinterpreters configure option and EXPERIMENTAL_ISOLATED_SUBINTERPRETERS macro have been removed.

  • gh-91924: Fix __lltrace__ debug feature if the stdout encoding is not UTF-8. Patch by Victor Stinner.

  • gh-93040: Wraps unused parameters in Objects/obmalloc.c with Py_UNUSED.

  • gh-93143: Avoid NULL checks for uninitialized local variables by determining at compile time which variables must be initialized.

  • gh-93061: Backward jumps after async for loops are no longer given dubious line numbers.

  • gh-93065: Fix contextvars HAMT implementation to handle iteration over deep trees.

    The bug was discovered and fixed by Eli Libman. See MagicStack/immutables#84 for more details.

  • gh-93012: Added the new function PyType_FromMetaclass(), which generalizes the existing PyType_FromModuleAndSpec() using an additional metaclass argument. This is useful for language binding tools, where it can be used to intercept type-related operations like subclassing or static attribute access by specifying a metaclass with custom slots.

    Importantly, PyType_FromMetaclass() is available in the Limited API, which provides a path towards migrating more binding tools onto the Stable ABI.

  • gh-93021: Fix the __text_signature__ for __get__() methods implemented in C. Patch by Jelle Zijlstra.

  • gh-89914: The operand of the YIELD_VALUE instruction is set to the stack depth. This is done to help frame handling on yield and may assist debuggers.

  • gh-92955: Fix memory leak in code object’s lines and positions iterators as they were not finalized at exit. Patch by Kumar Aditya.

  • gh-92930: Fixed a crash in _pickle.c from mutating collections during __reduce__ or persistent_id.

  • gh-90690: The PRECALL instruction has been removed. It offered only a small advantage for specialization and is not needed in the vast majority of cases.

  • gh-92914: Always round the allocated size for lists up to the nearest even number.

  • gh-92858: Improve error message for some suites with syntax error before “:”

  • gh-90473: Decrease default recursion limit on WASI to address limited call stack size.

  • gh-92804: Fix memory leak in memoryview iterator as it was not finalized at exit. Patch by Kumar Aditya.

  • gh-92777: Specialize LOAD_METHOD for objects with lazy dictionaries. Patch by Ken Jin.

  • gh-92658: Add support for connecting and binding to Hyper-V sockets on Windows Hyper-V hosts and guests.

  • gh-92236: Remove spurious «LINE» event when starting a generator or coroutine, visible tracing functions implemented in C.

  • gh-91102: _warnings.warn_explicit() is ported to Argument Clinic.

  • gh-92619: Make the compiler duplicate an exit block only if none of its instructions have a lineno (previously only the first instruction in the block was checked, leading to unnecessarily duplicated blocks).

  • gh-88750: The deprecated debug build only PYTHONTHREADDEBUG environment variable no longer does anything.

  • gh-92261: Fix hang when trying to iterate over a typing.Union.

  • gh-91432: Specialized the FOR_ITER opcode using the PEP 659 machinery

  • gh-91399: Removed duplicate “{0, 0, 0, 0, 0, 0}” entry in “Objects/unicodetype_db.h”.

  • gh-91578: Updates the error message for abstract class.

  • bpo-47091: Improve performance of repetition of list and tuple by using memcpy to copy data and performing the reference increments in one step.

  • bpo-46142: Make --help output shorter by moving some info to the new --help-env and --help-xoptions command-line options. Also add --help-all option to print complete usage.

  • bpo-42316: Document some places where an assignment expression needs parentheses.


  • gh-89237: Fix hang on Windows in subprocess.wait_closed() in asyncio with ProactorEventLoop. Patch by Kumar Aditya.

  • gh-97928: tkinter.Text.count() raises now an exception for options starting with «-» instead of silently ignoring them.

  • gh-98393: The os module no longer accepts bytes-like paths, like bytearray and memoryview types: only the exact bytes type is accepted for bytes strings. Patch by Victor Stinner.

  • gh-98363: Added itertools.batched() to batch data into lists of a given length with the last list possibly being shorter than the others.

  • gh-98331: Update the bundled copies of pip and setuptools to versions 22.3 and 65.5.0 respectively.

  • gh-98307: A createSocket() method was added to SysLogHandler.

  • gh-96035: Fix bug in urllib.parse.urlparse() that causes certain port numbers containing whitespace, underscores, plus and minus signs, or non-ASCII digits to be incorrectly accepted.

  • gh-98257: Make sys.setprofile() and sys.settrace() functions reentrant. They can no long fail with: RuntimeError("Cannot install a trace function while another trace function is being installed"). Patch by Victor Stinner.

  • gh-98251: Allow venv to pass along PYTHON* variables to ensurepip and pip when they do not impact path resolution

  • gh-94597: Deprecated asyncio.AbstractEventLoopPolicy.get_child_watcher() and asyncio.AbstractEventLoopPolicy.set_child_watcher() methods to be removed in Python 3.14. Patch by Kumar Aditya.

  • gh-98178: On macOS, fix a crash in syslog.syslog() in multi-threaded applications. On macOS, the libc syslog() function is not thread-safe, so syslog.syslog() no longer releases the GIL to call it. Patch by Victor Stinner.

  • gh-44098: Release the GIL when creating mmap.mmap objects on Unix.

  • gh-87730: Wrap network errors consistently in urllib FTP support, so the test suite doesn’t fail when a network is available but the public internet is not reachable.

  • gh-94597: The child watcher classes MultiLoopChildWatcher, FastChildWatcher and SafeChildWatcher are deprecated and will be removed in Python 3.14. Patch by Kumar Aditya.

  • gh-98023: Change default child watcher to PidfdChildWatcher on Linux systems which supports it. Patch by Kumar Aditya.

  • gh-90985: Earlier in 3.11 we deprecated asyncio.Task.cancel("message"). We realized we were too harsh, and have undeprecated it.

  • gh-65961: Do not rely solely on __cached__ on modules; code will also support __spec__.cached.

  • gh-97646: Replace deprecated application/javascript with text/javascript in mimetypes. See RFC 9239. Patch by Noam Cohen.

  • gh-97930: Apply changes from importlib_resources 5.8 and 5.9: Traversable.joinpath provides a concrete implementation. as_file now supports directories of resources.

  • gh-97850: Remove deprecated importlib.utils.set_loader() and importlib.utils.module_for_loader() from importlib.utils.

  • gh-97837: Change deprecate warning message in unittest from

    It is deprecated to return a value!=None


    It is deprecated to return a value that is not None from a test case

  • gh-97825: Fixes AttributeError when subprocess.check_output() is used with argument input=None and either of the arguments encoding or errors are used.

  • gh-97008: NameError and AttributeError spelling suggestions provided since gh-82711 are now also emitted by the pure Python traceback module. Tests for those suggestions now exercise both implementations to ensure they are equivalent. Patch by Carl Friedrich Bolz-Tereick and Łukasz Langa.

  • gh-97799: dataclass now uses inspect.get_annotations() to examine the annotations on class objects.

  • gh-97781: Removed deprecated interfaces in importlib.metadata (entry points accessed as dictionary, implicit dictionary construction of sequence of EntryPoint objects, mutablility of EntryPoints result, access of entry point by index). entry_points now has a simpler, more straightforward API (returning EntryPoints).

  • gh-96827: Avoid spurious tracebacks from asyncio when default executor cleanup is delayed until after the event loop is closed (e.g. as the result of a keyboard interrupt).

  • gh-95534: reads 10% faster.

  • gh-97592: Avoid a crash in the C version of asyncio.Future.remove_done_callback() when an evil argument is passed.

  • gh-97639: Remove tokenize.NL check from tabnanny.

  • gh-97545: Make Semaphore run faster.

  • gh-73588: Fix generation of the default name of tkinter.Checkbutton. Previously, checkbuttons in different parent widgets could have the same short name and share the same state if arguments «name» and «variable» are not specified. Now they are globally unique.

  • gh-96865: fix Flag to use boundary CONFORM

    This restores previous Flag behavior of allowing flags with non-sequential values to be combined; e.g.

    class Skip(Flag): TWO = 2 EIGHT = 8

    Skip.TWO | Skip.EIGHT -> <Skip.TWO|EIGHT: 10>

  • gh-97005: Update bundled libexpat to 2.4.9

  • gh-85760: Fix race condition in asyncio where process_exited() called before the pipe_data_received() leading to inconsistent output. Patch by Kumar Aditya.

  • gh-96704: Pass the correct contextvars.Context when a asyncio exception handler is called on behalf of a task or callback handle. This adds a new Task method, get_context, and also a new Handle method with the same name. If this method is not found on a task object (perhaps because it is a third-party library that does not yet provide this method), the context prevailing at the time the exception handler is called is used.

  • gh-96819: Fixed check in multiprocessing.resource_tracker that guarantees that the length of a write to a pipe is not greater than PIPE_BUF.

  • gh-95865: Reduce urllib.parse.quote_from_bytes() memory use on large values.

    Contributed by Dennis Sweeney.

  • gh-96741: Corrected type annotation for dataclass attribute pstats.FunctionProfile.ncalls to be str.

  • gh-96734: Update unicodedata database to Unicode 15.0.0.

  • gh-96735: Fix undefined behaviour in struct.unpack().

  • gh-46412: Improve performance of bool(db) for large ndb/gdb databases. Previously this would call len(db) which would iterate over all keys – the answer (empty or not) is known after the first key.

  • gh-96652: Fix the faulthandler implementation of faulthandler.register(signal, chain=True) if the sigaction() function is not available: don’t call the previous signal handler if it’s NULL. Patch by Victor Stinner.

  • gh-68163: Correct conversion of numbers.Rational’s to float.

  • gh-96538: Speed up bisect.bisect() functions by taking advantage of type-stability.

  • gh-96465: Fraction hashes are now cached.

  • gh-96079: In typing, fix missing field name and incorrect __module__ in _AnnotatedAlias.

  • gh-96415: Remove types._cell_factory from module namespace.

  • gh-95987: Fix repr of Any subclasses.

  • gh-96388: Work around missing socket functions in socket’s __repr__.

  • gh-96385: Fix TypeVarTuple.__typing_prepare_subst__. TypeError was not raised when using more than one TypeVarTuple, like [*T, *V] in type alias substitutions.

  • gh-96142: Add match_args, kw_only, slots, and weakref_slot to _DataclassParams.

  • gh-96073: In inspect, fix overeager replacement of «typing.» in formatting annotations.

  • gh-89258: Added a getChildren() method to logging.Logger, to get the immediate child loggers of a logger.

  • gh-96346: Use double caching for compiled RE patterns.

  • gh-96349: Fixed a minor performance regression in threading.Event.__init__()

  • gh-90467: Fix asyncio.streams.StreamReaderProtocol to keep a strong reference to the created task, so that it’s not garbage collected

  • gh-96172: Fix a bug in unicodedata: east_asian_width used to return the wrong value for unassigned characters; and for yet unassigned, but reserved characters.

  • gh-96159: Fix a performance regression in logging TimedRotatingFileHandler. Only check for special files when the rollover time has passed.

  • gh-96175: Fix unused localName parameter in the Attr class in xml.dom.minidom.

  • gh-96145: Add AttrDict to JSON module for use with object_hook.

  • gh-96052: Fix handling compiler warnings (SyntaxWarning and DeprecationWarning) in codeop.compile_command() when checking for incomplete input. Previously it emitted warnings and raised a SyntaxError. Now it always returns None for incomplete input without emitting any warnings.

  • gh-96125: Fix incorrect condition that causes to be wrong on pthread platforms.

  • gh-96019: Fix a bug in the script leading to about 13 KiB of space saving in the unicodedata module, specifically the character decomposition data.

  • gh-95463: Remove an incompatible change from bpo-28080 that caused a regression that ignored the utf8 in ZipInfo.flag_bits. Patch by Pablo Galindo.

  • gh-69142: Add %:z strftime format code (generates tzoffset with colons as separator), see Comportamiento strftime() y strptime().

  • gh-95899: Fix asyncio.Runner to call asyncio.set_event_loop() only once to avoid calling attach_loop() multiple times on child watchers. Patch by Kumar Aditya.

  • gh-95736: Fix unittest.IsolatedAsyncioTestCase to set event loop before calling setup functions. Patch by Kumar Aditya.

  • gh-95865: Speed up urllib.parse.quote_from_bytes() by replacing a list comprehension with map().

  • gh-95861: Add support for computing Spearman’s correlation coefficient to the existing statistics.correlation() function.

  • gh-95804: Fix logging shutdown handler so it respects MemoryHandler.flushOnClose.

  • gh-95704: When a task catches asyncio.CancelledError and raises some other error, the other error should generally not silently be suppressed.

  • gh-95149: The HTTPStatus enum offers a couple of properties to indicate the HTTP status category e.g. HTTPStatus.OK.is_success.

  • gh-95609: Update bundled pip to 22.2.2.

  • gh-95289: Fix asyncio.TaskGroup to propagate exception when asyncio.CancelledError was replaced with another exception by a context manger. Patch by Kumar Aditya and Guido van Rossum.

  • gh-94909: Fix incorrect joining of relative Windows paths with drives in pathlib.PurePath initializer.

  • gh-95385: Faster json.dumps() when sorting of keys is not requested (default).

  • gh-83901: Improve Signature.bind error message for missing keyword-only arguments.

  • gh-95339: Update bundled pip to 22.2.1.

  • gh-95045: Fix GC crash when deallocating _lsprof.Profiler by untracking it before calling any callbacks. Patch by Kumar Aditya.

  • gh-95231: Fail gracefully if EPERM or ENOSYS is raised when loading crypt methods. This may happen when trying to load MD5 on a Linux kernel with FIPS enabled.

  • gh-95097: Fix for asyncio.Task implementations without uncancel() method. Patch by Kumar Aditya.

  • gh-95087: Fix IndexError in parsing invalid date in the email module.

  • gh-95199: Upgrade bundled setuptools to 63.2.0.

  • gh-95194: Upgrade bundled pip to 22.2.

  • gh-93899: Fix check for existence of os.EFD_CLOEXEC, os.EFD_NONBLOCK and os.EFD_SEMAPHORE flags on older kernel versions where these flags are not present. Patch by Kumar Aditya.

  • gh-95166: Fix to cancel the currently waiting on future on an error - e.g. TimeoutError or KeyboardInterrupt.

  • gh-95132: Fix a sqlite3 regression where *args and **kwds were incorrectly relayed from connect() to the Connection factory. The regression was introduced in 3.11a1 with PR 24421 (gh-85128). Patch by Erlend E. Aasland.`

  • gh-93157: Fix fileinput module didn’t support errors option when inplace is true.

  • gh-91212: Fixed flickering of the turtle window when the tracer is turned off. Patch by Shin-myoung-serp.

  • gh-95077: Add deprecation warning for enum member.member access (e.g. Color.RED.BLUE).

  • gh-95109: Ensure that timeouts scheduled with asyncio.Timeout that have already expired are delivered promptly.

  • gh-95105: wsgiref.types.InputStream.__iter__() should return Iterator[bytes], not Iterable[bytes]. Patch by Shantanu Jain.

  • gh-95066: Replaced assert with exception in ast.parse(), when feature_version has an invalid major version. Patch by Shantanu Jain.

  • gh-77617: Add sqlite3 command-line interface. Patch by Erlend Aasland.

  • gh-95005: Replace _PyAccu with _PyUnicodeWriter in JSON encoder and StringIO and remove the _PyAccu implementation.

  • gh-90085: Remove -c/--clock and -t/--time CLI options of timeit. The options had been deprecated since Python 3.3 and the functionality was removed in Python 3.7. Patch by Shantanu Jain.

  • gh-94857: Fix refleak in _io.TextIOWrapper.reconfigure. Patch by Kumar Aditya.

  • gh-94821: Fix binding of unix socket to empty address on Linux to use an available address from the abstract namespace, instead of «0».

  • gh-94736: Fix crash when deallocating an instance of a subclass of _multiprocessing.SemLock. Patch by Kumar Aditya.

  • gh-81620: Add random.binomialvariate().

  • gh-74116: Allow asyncio.StreamWriter.drain() to be awaited concurrently by multiple tasks. Patch by Kumar Aditya.

  • gh-87822: When called with capture_locals=True, the traceback module functions swallow exceptions raised from calls to repr() on local variables of frames. This is in order to prioritize the original exception over rendering errors. An indication of the failure is printed in place of the missing value. (Patch by Simon-Martin Schroeder).

  • gh-88050: Fix asyncio subprocess transport to kill process cleanly when process is blocked and avoid RuntimeError when loop is closed. Patch by Kumar Aditya.

  • gh-94637: SSLContext.set_default_verify_paths() now releases the GIL around SSL_CTX_set_default_verify_paths call. The function call performs I/O and CPU intensive work.

  • gh-94309: Deprecate aliases typing.Hashable and typing.Sized

  • gh-92546: An undocumented python -m pprint benchmark is moved into pprint suite of pyperformance. Patch by Oleg Iarygin.

  • gh-94607: Fix subclassing complex generics with type variables in typing. Previously an error message saying Some type variables ... are not listed in Generic[...] was shown. typing no longer populates __parameters__ with the __parameters__ of a Python class.

  • gh-94619: Remove the long-deprecated module_repr() from importlib.

  • gh-93910: The ability to access the other values of an enum on an enum (e.g. Color.RED.BLUE) has been restored in order to fix a performance regression.

  • gh-93896: Fix and unittest.IsolatedAsyncioTestCase to always the set event loop as it was done in Python 3.10 and earlier. Patch by Kumar Aditya.

  • gh-94343: Allow setting the attributes of reprlib.Repr during object initialization

  • gh-94382: Port static types of _multiprocessing module to heap types. Patch by Kumar Aditya.

  • gh-78724: Fix crash in struct.Struct when it was not completely initialized by initializing it in __new__`(). Patch by Kumar Aditya.

  • gh-94510: Re-entrant calls to sys.setprofile() and sys.settrace() now raise RuntimeError. Patch by Pablo Galindo.

  • gh-92336: Fix bug where linecache.getline() fails on bad files with UnicodeDecodeError or SyntaxError. It now returns an empty string as per the documentation.

  • gh-94398: Once a asyncio.TaskGroup has started shutting down (i.e., at least one task has failed and the task group has started cancelling the remaining tasks), it should not be possible to add new tasks to the task group.

  • gh-94383: xml.etree: Remove the ElementTree.Element.copy() method of the pure Python implementation, deprecated in Python 3.10, use the copy.copy() function instead. The C implementation of xml.etree has no copy() method, only a __copy__() method. Patch by Victor Stinner.

  • gh-94379: zipimport: Remove find_loader() and find_module() methods, deprecated in Python 3.10: use the find_spec() method instead. See PEP 451 for the rationale. Patch by Victor Stinner.

  • gh-94352: shlex.split(): Passing None for s argument now raises an exception, rather than reading sys.stdin. The feature was deprecated in Python 3.9. Patch by Victor Stinner.

  • gh-94318: Strip trailing spaces in pydoc text output.

  • gh-89988: Fix memory leak in pickle.Pickler when looking up dispatch_table. Patch by Kumar Aditya.

  • gh-90016: Deprecate sqlite3 default adapters and converters. Patch by Erlend E. Aasland.

  • gh-94254: Fixed types of struct module to be immutable. Patch by Kumar Aditya.

  • gh-93259: Now raise ValueError when None or an empty string are passed to Distribution.from_name (and other callers).

  • gh-74696: shutil.make_archive() now passes the root_dir argument to custom archivers which support it.

  • gh-94216: The dis module now has the opcodes for pseudo instructions (those which are used by the compiler during code generation but then removed or replaced by real opcodes before the final bytecode is emitted).

  • gh-93096: Removed undocumented python -m codecs. Use python -m unittest test.test_codecs.EncodedFileTest instead.

  • gh-94207: Made _struct.Struct GC-tracked in order to fix a reference leak in the _struct module.

  • gh-93096: Removed undocumented -t argument of python -m base64. Use python -m unittest test.test_base64.LegacyBase64TestCase.test_encodebytes instead.

  • gh-94226: Remove the locale.format() function, deprecated in Python 3.7: use locale.format_string() instead. Patch by Victor Stinner.

  • gh-94199: Remove the ssl.match_hostname() function. The ssl.match_hostname() was deprecated in Python 3.7. OpenSSL performs hostname matching since Python 3.7, Python no longer uses the ssl.match_hostname() function. Patch by Victor Stinner.

  • gh-94214: Document the context object used in the venv.EnvBuilder class, and add the new environment’s library path to it.

  • gh-94199: Remove the ssl.wrap_socket() function, deprecated in Python 3.7: instead, create a ssl.SSLContext object and call its ssl.SSLContext.wrap_socket method. Any package that still uses ssl.wrap_socket() is broken and insecure. The function neither sends a SNI TLS extension nor validates server hostname. Code is subject to CWE-295: Improper Certificate Validation. Patch by Victor Stinner.

  • gh-94199: Remove the ssl.RAND_pseudo_bytes() function, deprecated in Python 3.6: use os.urandom() or ssl.RAND_bytes() instead. Patch by Victor Stinner.

  • gh-94199: hashlib: Remove the pure Python implementation of hashlib.pbkdf2_hmac(), deprecated in Python 3.10. Python 3.10 and newer requires OpenSSL 1.1.1 (PEP 644): this OpenSSL version provides a C implementation of pbkdf2_hmac() which is faster. Patch by Victor Stinner.

  • gh-94196: gzip: Remove the filename attribute of gzip.GzipFile, deprecated since Python 2.6, use the name attribute instead. In write mode, the filename attribute added '.gz' file extension if it was not present. Patch by Victor Stinner.

  • gh-94182: run the asyncio.PidfdChildWatcher on the running loop, this allows event loops to run subprocesses when there is no default event loop running on the main thread

  • gh-94169: Remove io.OpenWrapper and _pyio.OpenWrapper, deprecated in Python 3.10: just use open() instead. The open() ( function is a built-in function. Since Python 3.10, is also a static method. Patch by Victor Stinner.

  • gh-91742: Fix pdb crash after jump caused by a null pointer dereference. Patch by Kumar Aditya.

  • gh-94101: Manual instantiation of ssl.SSLSession objects is no longer allowed as it lead to misconfigured instances that crashed the interpreter when attributes where accessed on them.

  • gh-84753: inspect.iscoroutinefunction(), inspect.isgeneratorfunction(), and inspect.isasyncgenfunction() now properly return True for duck-typed function-like objects like instances of unittest.mock.AsyncMock.

    This makes inspect.iscoroutinefunction() consistent with the behavior of asyncio.iscoroutinefunction(). Patch by Mehdi ABAAKOUK.

  • gh-94028: Fix a regression in the sqlite3 where statement objects were not properly cleared and reset after use in cursor iters. The regression was introduced by PR 27884 in Python 3.11a1. Patch by Erlend E. Aasland.

  • gh-93973: Add keyword argument all_errors to asyncio.create_connection so that multiple connection errors can be raised as an ExceptionGroup.

  • gh-93963: Officially deprecate from classes moved to

  • gh-93858: Prevent error when activating venv in nested fish instances.

  • gh-93820: Pickle enum.Flag by name.

  • gh-93847: Fix repr of enum of generic aliases.

  • gh-91404: Revert the re memory leak when a match is terminated by a signal or memory allocation failure as the implemented fix caused a major performance regression.

  • gh-83499: Fix double closing of file description in tempfile.

  • gh-93820: Fixed a regression when copy.copy()-ing enum.Flag with multiple flag members.

  • gh-79512: Fixed names and __module__ value of weakref classes ReferenceType, ProxyType, CallableProxyType. It makes them pickleable.

  • gh-91389: Fix an issue where dis utilities could report missing or incorrect position information in the presence of CACHE entries.

  • gh-93626: Set __future__.annotations to have a None mandatoryRelease to indicate that it is currently “TBD”.

  • gh-90473: Emscripten and WASI have no home directory and cannot provide PEP 370 user site directory.

  • gh-90494: copy.copy() and copy.deepcopy() now always raise a TypeError if __reduce__() returns a tuple with length 6 instead of silently ignore the 6th item or produce incorrect result.

  • gh-90549: Fix a multiprocessing bug where a global named resource (such as a semaphore) could leak when a child process is spawned (as opposed to forked).

  • gh-93521: Fixed a case where dataclasses would try to add __weakref__ into the __slots__ for a dataclass that specified weakref_slot=True when it was already defined in one of its bases. This resulted in a TypeError upon the new class being created.

  • gh-79579: sqlite3 now correctly detects DML queries with leading comments. Patch by Erlend E. Aasland.

  • gh-93421: Update sqlite3.Cursor.rowcount when a DML statement has run to completion. This fixes the row count for SQL queries like UPDATE ... RETURNING. Patch by Erlend E. Aasland.

  • gh-93475: Expose FICLONE and FICLONERANGE constants in fcntl. Patch by Illia Volochii.

  • gh-93370: Deprecate sqlite3.version and sqlite3.version_info.

  • gh-91810: Suppress writing an XML declaration in open files in ElementTree.write() with encoding='unicode' and xml_declaration=None.

  • gh-91162: Support splitting of unpacked arbitrary-length tuple over TypeVar and TypeVarTuple parameters. For example:

    • A[T, *Ts][*tuple[int, ...]] -> A[int, *tuple[int, ...]]

    • A[*Ts, T][*tuple[int, ...]] -> A[*tuple[int, ...], int]

  • gh-93353: Fix the importlib.resources.as_file() context manager to remove the temporary file if destroyed late during Python finalization: keep a local reference to the os.remove() function. Patch by Victor Stinner.

  • gh-83658: Make multiprocessing.Pool raise an exception if maxtasksperchild is not None or a positive int.

  • gh-93312: Add os.PIDFD_NONBLOCK flag to open a file descriptor for a process with os.pidfd_open() in non-blocking mode. Patch by Kumar Aditya.

  • gh-88123: Implement Enum __contains__ that returns True or False to replace the deprecated behaviour that would sometimes raise a TypeError.

  • gh-93297: Make asyncio task groups prevent child tasks from being GCed

  • gh-85308: Changed argparse.ArgumentParser to use filesystem encoding and error handler instead of default text encoding to read arguments from file (e.g. fromfile_prefix_chars option). This change affects Windows; argument file should be encoded with UTF-8 instead of ANSI Codepage.

  • gh-93156: Accessing the pathlib.PurePath.parents sequence of an absolute path using negative index values produced incorrect results.

  • gh-93162: Add the ability for logging.config.dictConfig() to usefully configure QueueHandler and QueueListener as a pair, and add logging.getHandlerByName() and logging.getHandlerNames() APIs to allow access to handlers by name.

  • gh-93243: The smtpd module was removed per the schedule in PEP 594.

  • gh-92886: Replace assert statements with raise AssertionError() in BaseHandler so that the tested behaviour is maintained running with optimizations (-O).

  • gh-90155: Fix broken asyncio.Semaphore when acquire is cancelled.

  • gh-90817: The locale.resetlocale() function is deprecated and will be removed in Python 3.13. Use locale.setlocale(locale.LC_ALL, "") instead. Patch by Victor Stinner.

  • gh-91513: Added taskName attribute to logging module for use with asyncio tasks.

  • gh-74696: shutil.make_archive() no longer temporarily changes the current working directory during creation of standard .zip or tar archives.

  • gh-92728: The re.template() function and the corresponding re.TEMPLATE and re.T flags are restored after they were removed in 3.11.0b1, but they are now deprecated, so they might be removed from Python 3.13.

  • gh-93033: Search in some strings (platform dependent i.e [U+0xFFFF, U+0x0100] on Windows or [U+0xFFFFFFFF, U+0x00010000] on Linux 64-bit) are now up to 10 times faster.

  • gh-89973: Fix re.error raised in fnmatch if the pattern contains a character range with upper bound lower than lower bound (e.g. [c-a]). Now such ranges are interpreted as empty ranges.

  • gh-93044: No longer convert the database argument of sqlite3.connect() to bytes before passing it to the factory.

  • gh-93010: In a very special case, the email package tried to append the nonexistent InvalidHeaderError to the defect list. It should have been InvalidHeaderDefect.

  • gh-92986: Fix ast.unparse() when ImportFrom.level is None

  • gh-92932: Now dis() and get_instructions() handle operand values for instructions prefixed by EXTENDED_ARG_QUICK. Patch by Sam Gross and Dong-hee Na.

  • gh-92675: Fix venv.ensure_directories() to accept pathlib.Path arguments in addition to str paths. Patch by David Foster.

  • gh-87901: Removed the encoding argument from os.popen() that was added in 3.11b1.

  • gh-91922: Fix function sqlite.connect() and the sqlite.Connection constructor on non-UTF-8 locales. Also, they now support bytes paths non-decodable with the current FS encoding.

  • gh-92869: Added c_time_t to ctypes, which has the same size as the time_t type in C.

  • gh-92839: Fixed crash resulting from calling bisect.insort() or bisect.insort_left() with the key argument not equal to None.

  • gh-90473: subprocess now fails early on Emscripten and WASI platforms to work around missing os.pipe() on WASI.

  • gh-89325: Removed many old deprecated unittest features: TestCase method aliases, undocumented and broken TestCase method assertDictContainsSubset, undocumented TestLoader.loadTestsFromModule parameter use_load_tests, and an underscored alias of the TextTestResult class.

  • gh-92734: Allow multi-element reprs emitted by reprlib to be pretty-printed using configurable indentation.

  • gh-92671: Fixed ast.unparse() for empty tuples in the assignment target context.

  • gh-91581: utcfromtimestamp() no longer attempts to resolve fold in the pure Python implementation, since the fold is never 1 in UTC. In addition to being slightly faster in the common case, this also prevents some errors when the timestamp is close to datetime.min. Patch by Paul Ganssle.

  • gh-86388: Removed randrange() functionality deprecated since Python 3.10. Formerly, randrange(10.0) losslessly converted to randrange(10). Now, it raises a TypeError. Also, the exception raised for non-integral values such as randrange(10.5) or randrange(“10”) has been changed from ValueError to TypeError.

  • gh-90385: Add pathlib.Path.walk() as an alternative to os.walk().

  • gh-92550: Fix pathlib.Path.rglob() for empty pattern.

  • gh-92591: Allow logging filters to return a logging.LogRecord instance so that filters attached to logging.Handlers can enrich records without side effects on other handlers.

  • gh-92445: Fix a bug in argparse where nargs="*" would raise an error instead of returning an empty list when 0 arguments were supplied if choice was also defined in parser.add_argument.

  • gh-92547: Remove undocumented sqlite3 features deprecated in Python 3.10:

    • sqlite3.enable_shared_cache()

    • sqlite3.OptimizedUnicode

    Patch by Erlend E. Aasland.

  • gh-92530: Fix an issue that occurred after interrupting threading.Condition.notify().

  • gh-92531: The statistics.median_grouped() function now always return a float. Formerly, it did not convert the input type when for sequences of length one.

  • gh-84131: The pathlib.Path deprecated method link_to has been removed. Use 3.10’s hardlink_to() method instead as its semantics are consistent with that of symlink_to().

  • gh-89336: Removed configparser module APIs: the SafeConfigParser class alias, the ParsingError.filename property and parameter, and the ConfigParser.readfp method, all of which were deprecated since Python 3.2.

  • gh-92391: Add __class_getitem__() to csv.DictReader and csv.DictWriter, allowing them to be parameterized at runtime. Patch by Marc Mueller.

  • gh-91968: Add SO_RTABLE and SO_USER_COOKIE constants to socket.

  • gh-91810: ElementTree method write() and function tostring() now use the text file’s encoding («UTF-8» if not available) instead of locale encoding in XML declaration when encoding="unicode" is specified.

  • gh-81790: os.path.splitdrive() now understands DOS device paths with UNC links (beginning \\?\UNC\). Contributed by Barney Gale.

  • gh-91760: Apply more strict rules for numerical group references and group names in regular expressions. Only sequence of ASCII digits is now accepted as a numerical reference. The group name in bytes patterns and replacement strings can now only contain ASCII letters and digits and underscore.

  • gh-90622: Worker processes for concurrent.futures.ProcessPoolExecutor are no longer spawned on demand (a feature added in 3.9) when the multiprocessing context start method is "fork" as that can lead to deadlocks in the child processes due to a fork happening while threads are running.

  • gh-91577: Move imports in SharedMemory methods to module level so that they can be executed late in python finalization.

  • gh-91581: Remove an unhandled error case in the C implementation of calls to datetime.fromtimestamp with no time zone (i.e. getting a local time from an epoch timestamp). This should have no user-facing effect other than giving a possibly more accurate error message when called with timestamps that fall on 10000-01-01 in the local time. Patch by Paul Ganssle.

  • gh-91539: Improve performance of urllib.request.getproxies_environment when there are many environment variables

  • gh-91524: Speed up the regular expression substitution (functions re.sub() and re.subn() and corresponding re.Pattern methods) for replacement strings containing group references by 2–3 times.

  • gh-91447: Fix findtext in the xml module to only give an empty string when the text attribute is set to None.

  • gh-91456: Deprecate current default auto() behavior: In 3.13 the default will be for for auto() to always return the largest member value incremented by 1, and to raise if incompatible value types are used.

  • bpo-47231: Fixed an issue with inconsistent trailing slashes in tarfile longname directories.

  • bpo-39064: zipfile.ZipFile now raises zipfile.BadZipFile instead of ValueError when reading a corrupt zip file in which the central directory offset is negative.

  • bpo-41287: Fix handling of the doc argument in subclasses of property().

  • gh-90005: ctypes dependency libffi is now detected with pkg-config.

  • bpo-32547: The constructors for DictWriter and DictReader now coerce the fieldnames argument to a list if it is an iterator.

  • bpo-35540: Fix dataclasses.asdict() crash when collections.defaultdict is present in the attributes.

  • bpo-47063: Add an index_pages parameter to support using non-default index page names.

  • bpo-47025: Drop support for bytes on sys.path.

  • bpo-46951: Order the contents of zipapp archives, to make builds more reproducible.

  • bpo-42777: Implement pathlib.Path.is_mount() for Windows paths.

  • bpo-46755: In QueueHandler, clear stack_info from LogRecord to prevent stack trace from being written twice.

  • bpo-45393: Fix the formatting for await x and not x in the operator precedence table when using the help() system.

  • bpo-46642: Improve error message when trying to subclass an instance of typing.TypeVar, typing.ParamSpec, typing.TypeVarTuple, etc. Based on patch by Gregory Beauregard.

  • bpo-46364: Restrict use of sockets instead of pipes for stdin of subprocesses created by asyncio to AIX platform only.

  • bpo-28249: Set doctest.DocTest.lineno to None when object does not have __doc__.

  • bpo-46197: Fix ensurepip environment isolation for subprocess running pip.

  • bpo-45924: Fix asyncio incorrect traceback when future’s exception is raised multiple times. Patch by Kumar Aditya.

  • bpo-45046: Add support of context managers in unittest: methods enterContext() and enterClassContext() of class TestCase, method enterAsyncContext() of class IsolatedAsyncioTestCase and function unittest.enterModuleContext().

  • bpo-44173: Enable fast seeking of uncompressed unencrypted zipfile.ZipExtFile

  • bpo-42627: Fix incorrect parsing of Windows registry proxy settings

  • bpo-42047: Add threading.get_native_id() support for DragonFly BSD. Patch by David Carlier.

  • bpo-14243: The tempfile.NamedTemporaryFile function has a new optional parameter delete_on_close

  • bpo-41246: Give the same callback function for when the overlapped operation is done to the functions recv, recv_into, recvfrom, sendto, send and sendfile inside IocpProactor.

  • bpo-39264: Fixed collections.UserDict.get() to not call __missing__() when a value is not found. This matches the behavior of dict. Patch by Bar Harel.

  • bpo-38693: importlib now uses f-strings internally instead of str.format.

  • bpo-38267: Add timeout parameter to asyncio.loop.shutdown_default_executor(). The default value is None, which means the executor will be given an unlimited amount of time. When called from asyncio.Runner or, the default timeout is 5 minutes.

  • bpo-34828: sqlite3.Connection.iterdump() now handles databases that use AUTOINCREMENT in one or more tables.

  • bpo-32990: Support reading wave files with the WAVE_FORMAT_EXTENSIBLE format in the wave module.

  • bpo-26253: Allow adjustable compression level for tarfile streams in


  • gh-85525: Remove extra row

  • gh-86404: Deprecated tools make suspicious and are now removed. They have been replaced by spinx-lint.

  • gh-97741: Fix ! in c domain ref target syntax via a patch, so it works as intended to disable ref target resolution.

  • gh-96432: Fraction literals now support whitespace around the forward slash, Fraction('2 / 3').

  • gh-96098: Improve discoverability of the higher level concurrent.futures module by providing clearer links from the lower level threading and multiprocessing modules.

  • gh-95957: What’s New 3.11 now has instructions for how to provide compiler and linker flags for Tcl/Tk and OpenSSL on RHEL 7 and CentOS 7.

  • gh-95588: Clarified the conflicting advice given in the ast documentation about ast.literal_eval() being «safe» for use on untrusted input while at the same time warning that it can crash the process. The latter statement is true and is deemed unfixable without a large amount of work unsuitable for a bugfix. So we keep the warning and no longer claim that literal_eval is safe.

  • gh-91207: Fix stylesheet not working in Windows CHM htmlhelp docs and add warning that they are deprecated. Contributed by C.A.M. Gerlach.

  • gh-95454: Replaced incorrectly written true/false values in documentiation. Patch by Robert O’Shea

  • gh-95451: Update library documentation with availability information on WebAssembly platforms wasm32-emscripten and wasm32-wasi.

  • gh-95415: Use consistent syntax for platform availability. The directive now supports a content body and emits a warning when it encounters an unknown platform.

  • gh-94321: Document the PEP 246 style protocol type sqlite3.PrepareProtocol.

  • gh-86128: Document a limitation in ThreadPoolExecutor where its exit handler is executed before any handlers in atexit.

  • gh-61162: Clarify sqlite3 behavior when Como usar la conexión con un administrador de contexto.

  • gh-87260: Align sqlite3 argument specs with the actual implementation.

  • gh-86986: The minimum Sphinx version required to build the documentation is now 3.2.

  • gh-88831: Augmented documentation of asyncio.create_task(). Clarified the need to keep strong references to tasks and added a code snippet detailing how to do this.

  • gh-86438: Clarify that -W and PYTHONWARNINGS are matched literally and case-insensitively, rather than as regular expressions, in warnings.

  • gh-93031: Update tutorial introduction output to use 3.10+ SyntaxError invalid range.

  • gh-92240: Added release dates for «What’s New in Python 3.X» for 3.0, 3.1, 3.2, 3.8 and 3.10

  • bpo-47161: Document that pathlib.PurePath does not collapse initial double slashes because they denote UNC paths.

  • bpo-40838: Document that inspect.getdoc(), inspect.getmodule(), and inspect.getsourcefile() might return None.

  • bpo-43689: The Differ documentation now also mentions other whitespace characters, which make it harder to understand the diff output.

  • bpo-38056: Overhaul the Manejadores de errores documentation in codecs.

  • bpo-13553: Document tkinter.Tk args.


  • gh-95027: On Windows, when the Python test suite is run with the -jN option, the ANSI code page is now used as the encoding for the stdout temporary file, rather than using UTF-8 which can lead to decoding errors. Patch by Victor Stinner.

  • gh-96624: Fixed the failure of repeated runs of test.test_unittest caused by side effects in test_dotted_but_module_not_loaded.

  • gh-95243: Mitigate the inherent race condition from using find_unused_port() in testSockName() by trying to find an unused port a few times before failing. Patch by Ross Burton.

  • gh-95573: Lib/test/test_asyncio/ exposed a bug in the macOS kernel where intense concurrent load on non-blocking sockets occasionally causes errno.ENOBUFS («No buffer space available») to be emitted. FB11063974 filed with Apple, in the mean time as a workaround buffer size used in tests on macOS is decreased to avoid intermittent failures. Patch by Fantix King.

  • gh-95280: Fix problem with test_ssl test_get_ciphers on systems that require perfect forward secrecy (PFS) ciphers.

  • gh-95212: Make multiprocessing test case test_shared_memory_recreate parallel-safe.

  • gh-95218: Move tests for importlib.resources into test_importlib.resources.

  • gh-93963: Updated tests to use preferred location for importlib.resources ABCs.

  • gh-94675: Add a regression test for re exponentional slowdown when using rjsmin.

  • gh-91330: Added more tests for dataclasses to cover behavior with data descriptor-based fields.

  • gh-94208: test_ssl is now checking for supported TLS version and protocols in more tests.

  • gh-94315: Tests now check for DAC override capability instead of relying on os.geteuid().

  • gh-54781: Rename test_tk to test_tkinter, and rename test_ttk_guionly to test_ttk. Patch by Victor Stinner.

  • gh-93839: Move Lib/ctypes/test/ to Lib/test/test_ctypes/. Patch by Victor Stinner.

  • gh-93951: In test_bdb.StateTestCase.test_skip, avoid including auxiliary importers.

  • gh-93957: Provide nicer error reporting from subprocesses in test_venv.EnsurePipTest.test_with_pip.

  • gh-93884: Add test cases for PyNumber_ToBase() that take a large number or a non-int object as parameter.

  • gh-93852: test_asyncio, test_logging, test_socket and test_socketserver now create AF_UNIX domains in the current directory to no longer fail with OSError("AF_UNIX path too long") if the temporary directory (the TMPDIR environment variable) is too long. Patch by Victor Stinner.

  • gh-93353: regrtest now checks if a test leaks temporary files or directories if run with -jN option. Patch by Victor Stinner.

  • gh-84461: now handles cross compiling env vars correctly and pass HOSTRUNNER to regression tests.

  • gh-93616: test_modulefinder now creates a temporary directory in ModuleFinderTest.setUp() instead of module scope.

  • gh-93575: Fix issue with test_unicode test_raiseMemError. The test case now use to calculate size of PyUnicode structs. sys.getsizeof() may return different size when string has UTF-8 memory.

  • gh-90473: WASI does not have a chmod(2) syscall. os.chmod() is now a dummy function on WASI. Skip all tests that depend on working os.chmod().

  • gh-90473: Skip tests on WASI that require symlinks with absolute paths.

  • gh-57539: Increase calendar test coverage for calendar.LocaleTextCalendar.formatweekday().

  • gh-90473: Skip symlink tests on WASI. wasmtime uses openat2(2) with RESOLVE_BENEATH flag, which prevents symlinks with absolute paths.

  • gh-89858: Fix test_embed for out-of-tree builds. Patch by Kumar Aditya.

  • gh-92886: Fixing tests that fail when running with optimizations (-O) in

  • gh-92886: Fixing tests that fail when running with optimizations (-O) in

  • gh-92886: Fixing tests that fail when running with optimizations (-O) in

  • gh-92886: Fixing tests that fail when running with optimizations (-O) in

  • gh-92886: Fixing tests that fail when running with optimizations (-O) in

  • gh-92670: Skip test_shutil.TestCopy.test_copyfile_nonexistent_dir test on AIX as the test uses a trailing slash to force the OS consider the path as a directory, but on AIX the trailing slash has no effect and is considered as a file.

  • gh-92514: Remove unused Patch by Jelle Zijlstra.

  • bpo-47016: Create a GitHub Actions workflow for verifying bundled pip and setuptools. Patch by Illia Volochii and Adam Turner.


  • gh-96761: Fix the build process of clang compiler for _bootstrap_python if LTO optimization is applied. Patch by Matthias Görgens and Dong-hee Na.

  • gh-96883: wasm32-emscripten builds for browsers now include concurrent.futures for asyncio and unittest.mock.

  • gh-85936: CPython now uses the ThinLTO option as the default policy if the Clang compiler accepts the flag. Patch by Dong-hee Na.

  • gh-96729: Ensure that Windows releases built with Tools\msi\buildrelease.bat are upgradable to and from official Python releases.

  • gh-96269: Shared module targets now depend on new MODULE_DEPS variable, which includes EXPORTSYMS. This fixes a build order issue on unsupported AIX platform.

  • gh-84461: wasm32-emscripten platform no longer builds resource module, getresuid(), getresgid(), and their setters. The APIs are stubs and not functional.

  • gh-95973: Add a new --with-dsymutil configure option to link debug information in macOS. Patch by Pablo Galindo.

  • gh-90536: Use the BOLT post-link optimizer to improve performance, particularly on medium-to-large applications.

  • gh-93744: Remove the configure --with-cxx-main build option: it didn’t work for many years. Remove the MAINCC variable from configure and Makefile. Patch by Victor Stinner.

  • gh-94801: Fix a regression in configure script that caused some header checks to ignore custom CPPFLAGS. The regression was introduced in gh-94802.

  • gh-95145: wasm32-wasi builds no longer depend on WASIX’s pthread stubs. Python now has its own stubbed pthread API.

  • gh-95174: Python now detects missing dup function in WASI and works around some missing errno, select, and socket constants.

  • gh-95174: Python now skips missing socket functions and methods on WASI. WASI can only create sockets from existing fd / accept and has no netdb.

  • gh-95085: Platforms wasm32-unknown-emscripten and wasm32-unknown-wasi have been promoted to PEP 11 tier 3 platform support.

  • gh-94847: Fixed _decimal module build issue on GCC when compiling with LTO and pydebug. Debug builds no longer force inlining of functions.

  • gh-94841: Fix the possible performance regression of PyObject_Free() compiled with MSVC version 1932.

  • gh-94801: configure now uses custom flags like ZLIB_CFLAGS and ZLIB_LIBS when searching for headers and libraries.

  • gh-94773: now supports code object with frozensets that contain incompatible, unsortable types.

  • gh-94682: Build and test with OpenSSL 1.1.1q

  • gh-90005: Dependencies of readline and curses module are now detected in configure script with pkg-config. Only ncurses / ncursesw are detected automatically. The old curses library is not configured automatically. Workaround for missing termcap or tinfo library has been removed.

  • gh-90005: Fix building _ctypes extension without pkg-config.

  • gh-90005: _dbm module dependencies are now detected by configure.

  • gh-94404: makesetup now works around an issue with sed on macOS and uses correct CFLAGS for object files that end up in a shared extension. Module CFLAGS are used before PY_STDMODULE_CFLAGS to avoid clashes with system headers.

  • gh-93939: C extension modules are now built by configure and make instead of distutils and

  • gh-93939: The 2to3, idle, and pydoc scripts are now generated and installed by Makefile instead of

  • gh-94280: Updated pegen regeneration script on Windows to find and use Python 3.9 or higher. Prior to this, pegen regeneration already required 3.9 or higher, but the script may have used lower versions of Python.

  • gh-93584: Address race condition in Makefile when installing a PGO build. All test and install targets now depend on all target.

  • gh-93491: configure now detects and reports PEP 11 support tiers.

  • gh-69093: Fix Modules/ rule for _sqlite3 extension.

  • gh-93207: va_start() with two parameters, like va_start(args, format), is now required to build Python. va_start() is no longer called with a single parameter. Patch by Kumar Aditya.

  • gh-93202: Python now always use the %zu and %zd printf formats to format a size_t or Py_ssize_t number. Building Python 3.12 requires a C11 compiler, so these printf formats are now always supported. Patch by Victor Stinner.

  • gh-90473: Disable pymalloc and increase stack size on wasm32-wasi.

  • bpo-34449: Drop invalid compiler switch -fPIC for HP aCC on HP-UX. Patch by Michael Osipov.


  • gh-98360: Fixes multiprocessing spawning child processes on Windows from a virtual environment to ensure that child processes that also use multiprocessing to spawn more children will recognize that they are in a virtual environment.

  • gh-98414: Fix py.exe launcher handling of -V:<company>/ option when default preferences have been set in environment variables or configuration files.

  • gh-97728: Fix possible crashes caused by the use of uninitialized variables when pass invalid arguments in os.system() on Windows and in Windows-specific modules (like winreg).

  • gh-90989: Made Lanzador de Python para Windows install per-user by default (unless an all users install already exists), and clarify some text in the installer.

  • gh-97649: The Tools directory is no longer installed on Windows

  • gh-96965: Update libffi to 3.4.3

  • gh-96577: Fixes a potential buffer overrun in msilib.

  • gh-96559: Fixes the Windows launcher not using the compatible interpretation of default tags found in configuration files when no tag was passed to the command.

  • gh-94781: Fix pcbuild.proj to clean previous instances of output files in Python\deepfreeze and Python\frozen_modules directories on Windows. Patch by Charlie Zhao.

  • gh-89545: Updates platform code getting the Windows version to use native Windows Management Instrumentation (WMI) queries to determine OS version, type, and architecture.

  • gh-95733: Make certain requirements of the Windows Store package optional to allow installing on earlier updates of Windows.

  • gh-95656: Enable the enable_load_extension() sqlite3 API.

  • gh-95587: Fixes some issues where the Windows installer would incorrectly detect certain features of an existing install when upgrading.

  • gh-94399: Restores the behaviour of Lanzador de Python para Windows for /usr/bin/env shebang lines, which will now search PATH for an executable matching the given command. If none is found, the usual search process is used.

  • gh-95445: Fixes the unsuccessful removal of the HTML document directory when uninstalling with Windows msi.

  • gh-95359: Fix Lanzador de Python para Windows handling of py.ini commands (it was incorrectly expecting a py_ prefix on keys) and crashes when reading per-user configuration file.

  • gh-95285: Fix Lanzador de Python para Windows handling of command lines where it is only passed a short executable name.

  • gh-90844: Allow virtual environments to correctly launch when they have spaces in the path.

  • gh-94772: Fix incorrect handling of shebang lines in py.exe launcher

  • gh-94018: zipfile will now remove trailing spaces from path components when extracting files on Windows.

  • gh-93824: Drag and drop of files onto Python files in Windows Explorer has been enabled for Windows ARM64.

  • gh-43414: os.get_terminal_size() now attempts to read the size from any provided handle, rather than only supporting file descriptors 0, 1 and 2.

  • gh-92817: Ensures that py.exe will prefer an active virtual environment over default tags specified with environment variables or through a py.ini file.

  • gh-92984: Explicitly disable incremental linking for non-Debug builds

  • gh-92841: asyncio no longer throws RuntimeError: Event loop is closed on interpreter exit after asynchronous socket activity. Patch by Oleg Iarygin.

  • bpo-46907: Update Windows installer to use SQLite 3.38.4.

  • gh-91061: Accept os.PathLike for the argument to winsound.PlaySound

  • bpo-42658: Support native Windows case-insensitive path comparisons by using LCMapStringEx instead of str.lower() in ntpath.normcase(). Add LCMapStringEx to the _winapi module.

  • bpo-38704: Prevent installation on unsupported Windows versions.


  • gh-97897: The macOS 13 SDK includes support for the mkfifoat and mknodat system calls. Using the dir_fd option with either os.mkfifo() or os.mknod() could result in a segfault if cpython is built with the macOS 13 SDK but run on an earlier version of macOS. Prevent this by adding runtime support for detection of these system calls («weaklinking») as is done for other newer syscalls on macOS.


  • gh-97527: Fix a bug in the previous bugfix that caused IDLE to not start when run with 3.10.8, 3.12.0a1, and at least Microsoft Python 3.10.2288.0 installed without the Lib/test package. 3.11.0 was never affected.

  • gh-65802: Document handling of extensions in Save As dialogs.

  • gh-95191: Include prompts when saving Shell (interactive input and output).

  • gh-95511: Fix the Shell context menu copy-with-prompts bug of copying an extra line when one selects whole lines.

  • gh-95471: In the Edit menu, move Select All and add a new separator.

  • gh-95411: Enable using IDLE’s module browser with .pyw files.

  • gh-89610: Add .pyi as a recognized extension for IDLE on macOS. This allows opening stub files by double clicking on them in the Finder.


  • gh-68686: Remove ptags and eptags scripts.

  • gh-97681: Remove the Tools/demo/ directory which contained old demo scripts. A copy can be found in the old-demos project. Patch by Victor Stinner.

  • gh-97669: Remove outdated example scripts of the Tools/scripts/ directory. A copy can be found in the old-demos project. Patch by Victor Stinner.

  • gh-95853: The script now pre-builds Emscripten ports, checks for broken EMSDK versions, and warns about pkg-config env vars.

  • gh-95853: The new tool Tools/wasm/ automates configure, compile, and test steps for building CPython on WebAssembly platforms.

  • gh-95731: Fix handling of module docstrings in Tools/i18n/

  • gh-93939: Add script Tools/scripts/ to check and validate builtin and shared extension modules. The script also handles Modules/Setup and will eventually replace

  • gh-94538: Fix Argument Clinic output to custom file destinations. Patch by Erlend E. Aasland.

  • gh-94430: Allow parameters named module and self with custom C names in Argument Clinic. Patch by Erlend E. Aasland

  • gh-86087: The Tools/scripts/ script used to parse HTML4 entities has been removed.


Python 3.11.0 beta 1

Release date: 2022-05-06


  • gh-57684: Add the -P command line option and the PYTHONSAFEPATH environment variable to not prepend a potentially unsafe path to sys.path. Patch by Victor Stinner.

Core and Builtins

  • gh-89519: Chaining classmethod descriptors (introduced in bpo-19072) is deprecated. It can no longer be used to wrap other descriptors such as property(). The core design of this feature was flawed, and it caused a number of downstream problems.

  • gh-92345: pymain_run_python() now imports readline and rlcompleter before sys.path is extended to include the current working directory of an interactive interpreter. Non-interactive interpreters are not affected.

  • bpo-43857: Improve the AttributeError message when deleting a missing attribute. Patch by Géry Ogam.

  • gh-92245: Make sure that PEP 523 is respected in all cases. In 3.11a7, specialization may have prevented Python-to-Python calls respecting PEP 523.

  • gh-92203: Add a closure keyword-only parameter to exec(). It can only be specified when exec-ing a code object that uses free variables. When specified, it must be a tuple, with exactly the number of cell variables referenced by the code object. closure has a default value of None, and it must be None if the code object doesn’t refer to any free variables.

  • gh-91173: Disable frozen modules in debug builds. Patch by Kumar Aditya.

  • gh-92114: Improve error message when subscript a type with __class_getitem__ set to None.

  • gh-92112: Fix crash triggered by an evil custom mro() on a metaclass.

  • gh-92063: The PRECALL_METHOD_DESCRIPTOR_FAST_WITH_KEYWORDS instruction now ensures methods are called only on objects of the correct type.

  • gh-92031: Deoptimize statically allocated code objects during Py_FINALIZE() so that future _PyCode_Quicken calls always start with unquickened code.

  • gh-92036: Fix a crash in subinterpreters related to the garbage collector. When a subinterpreter is deleted, untrack all objects tracked by its GC. To prevent a crash in deallocator functions expecting objects to be tracked by the GC, leak a strong reference to these objects on purpose, so they are never deleted and their deallocator functions are not called. Patch by Victor Stinner.

  • gh-92032: The interpreter can now autocomplete soft keywords, as of now match, case, and _ (wildcard pattern) from PEP 634.

  • gh-87999: The warning emitted by the Python parser for a numeric literal immediately followed by keyword has been changed from deprecation warning to syntax warning.

  • gh-91869: Fix an issue where specialized opcodes with extended arguments could produce incorrect tracing output or lead to assertion failures.

  • gh-91603: Speed up types.UnionType instantiation. Based on patch provided by Yurii Karabas.

  • gh-89373: If Python is built in debug mode, Python now ensures that deallocator functions leave the current exception unchanged. Patch by Victor Stinner.

  • gh-91632: Fix a minor memory leak at exit: release the memory of the generic_alias_iterator type. Patch by Dong-hee Na.

  • gh-81548: Octal escapes with value larger than 0o377 now produce a DeprecationWarning. In a future Python version they will be a SyntaxWarning and eventually a SyntaxError.

  • bpo-43950: Use a single compact table for line starts, ends and column offsets. Reduces memory consumption for location info by half

  • gh-91102: Use Argument Clinic for EncodingMap. Patch by Oleg Iarygin.

  • gh-91636: Fixed a crash in a garbage-collection edge-case, in which a PyFunction_Type.tp_clear function could leave a python function object in an inconsistent state.

  • gh-91603: Speed up isinstance() and issubclass() checks for types.UnionType. Patch by Yurii Karabas.

  • gh-91625: Fixed a bug in which adaptive opcodes ignored any preceding EXTENDED_ARGs on specialization failure.

  • gh-78607: The LLTRACE special build now looks for the name __lltrace__ defined in module globals, rather than the name __ltrace__, which had been introduced as a typo.

  • gh-91576: Speed up iteration of ascii strings by 50%. Patch by Kumar Aditya.

  • gh-89279: Improve interpreter performance on Windows by inlining a few specific macros.

  • gh-91502: Add a new _PyFrame_IsEntryFrame() API function, to check if a PyFrameObject is an entry frame. Patch by Pablo Galindo.

  • gh-91266: Refactor the bytearray strip methods strip, lstrip and rstrip to use a common implementation.

  • gh-91479: Replaced the __note__ field of BaseException (added in an earlier version of 3.11) with the final design of PEP 678. Namely, BaseException gets an add_note() method, and its __notes__ field is created when necessary.

  • gh-46055: Speed up right shift of negative integers, by removing unnecessary creation of temporaries. Original patch by Xinhang Xu, reworked by Mark Dickinson.

  • gh-91462: Make the interpreter’s low-level tracing (lltrace) feature output more readable by displaying opcode names (rather than just numbers), and by displaying stack contents before each opcode.

  • gh-89455: Fixed an uninitialized bool value in the traceback printing code path that was introduced by the initial bpo-45292 exception groups work.

  • gh-91421: Fix a potential integer overflow in _Py_DecodeUTF8Ex.

  • gh-91428: Add static const char *const _PyOpcode_OpName[256] = {...}; to opcode.h for debug builds to assist in debugging the Python interpreter. It is now more convenient to make various forms of debugging output more human-readable by including opcode names rather than just the corresponding decimal digits.

  • bpo-47120: Make POP_JUMP_IF_TRUE, POP_JUMP_IF_FALSE, POP_JUMP_IF_NONE and POP_JUMP_IF_NOT_NONE virtual, mapping to new relative jump opcodes.

  • bpo-45317: Add internal documentation explaining design of new (for 3.11) frame stack.

  • bpo-47197: ctypes used to mishandle void return types, so that for instance a function declared like ctypes.CFUNCTYPE(None, ctypes.c_int) would be called with signature int f(int) instead of void f(int). Wasm targets require function pointers to be called with the correct signatures so this led to crashes. The problem is now fixed.

  • bpo-47120: Make opcodes JUMP_IF_TRUE_OR_POP and JUMP_IF_FALSE_OR_POP relative rather than absolute.

  • bpo-47177: Replace the f_lasti member of the internal _PyInterpreterFrame structure with a prev_instr pointer, which reduces overhead in the main interpreter loop. The f_lasti attribute of Python-layer frame objects is preserved for backward-compatibility.

  • bpo-46961: Integer mod/remainder operations, including the three-argument form of pow(), now consistently return ints from the global small integer cache when applicable.

  • bpo-46962: Classes and functions that unconditionally declared their docstrings ignoring the --without-doc-strings compilation flag no longer do so.

    The classes affected are ctypes.UnionType, pickle.PickleBuffer, testcapi.RecursingInfinitelyError, and types.GenericAlias.

    The functions affected are 24 methods in ctypes.

    Patch by Oleg Iarygin.

  • bpo-46942: Use Argument Clinic for the types.MethodType constructor. Patch by Oleg Iarygin.

  • bpo-46764: Fix wrapping bound methods with @classmethod

  • bpo-43464: Optimize set.intersection() for non-set arguments.

  • bpo-46721: Optimize set.issuperset() for non-set argument.

  • bpo-46509: Add type-specialized versions of the Py_DECREF(), and use them for float, int, str, bool, and None to avoid pointer-chasing at runtime where types are known at C compile time.

  • bpo-46045: Do not use POSIX semaphores on NetBSD

  • bpo-36819: Fix crashes in built-in encoders with error handlers that return position less or equal than the starting position of non-encodable characters.

  • bpo-34093: marshal.dumps() uses FLAG_REF for all interned strings. This makes output more deterministic and helps reproducible build.

  • bpo-26579: Added object.__getstate__ which provides the default implementation of the __getstate__() method.

    Copying and pickling instances of subclasses of builtin types bytearray, set, frozenset, collections.OrderedDict, collections.deque, weakref.WeakSet, and datetime.tzinfo now copies and pickles instance attributes implemented as slots.


  • gh-87901: Add the encoding parameter to os.popen().

  • gh-90997: Fix an issue where dis utilities may interpret populated inline cache entries as valid instructions.

  • gh-92332: Deprecate typing.Text (removal of the class is currently not planned). Patch by Alex Waygood.

  • Deprecate nested classes in enum definitions becoming members – in 3.13 they will be normal classes; add member and nonmember functions to allow control over results now.

  • gh-92356: Fixed a performance regression in ctypes function calls.

  • gh-90997: Show the actual named values stored in inline caches when show_caches=True is passed to dis utilities.

  • gh-92301: Prefer close_range() to iterating over procfs for file descriptor closing in subprocess for better performance.

  • gh-67248: Sort the miscellaneous topics in Cmd.do_help()

  • gh-92210: Port socket.__init__ to Argument Clinic. Patch by Cinder.

  • gh-80010: Add support for generalized ISO 8601 parsing to datetime.datetime.fromisoformat(), and datetime.time.fromisoformat(). Patch by Paul Ganssle.

  • gh-92118: Fix a 3.11 regression in contextmanager(), which caused it to propagate exceptions with incorrect tracebacks.

  • gh-90887: Adding COPYFILE_STAT, COPYFILE_ACL and COPYFILE_XATTR constants for os.fcopyfile() available in macOs.

  • gh-91215: For @dataclass, add weakref_slot. Default is False. If True, and if slots=True, add a slot named «__weakref__», which will allow instances to be weakref’d. Contributed by Eric V. Smith

  • gh-85984: New function os.login_tty() for Unix.

  • gh-92128: Add __class_getitem__() to logging.LoggerAdapter and logging.StreamHandler, allowing them to be parameterized at runtime. Patch by Alex Waygood.

  • gh-92049: Forbid pickling constants re._constants.SUCCESS etc. Previously, pickling did not fail, but the result could not be unpickled.

  • gh-92062: inspect.Parameter now raises ValueError if name is a keyword, in addition to the existing check that it is an identifier.

  • gh-87390: Add an __unpacked__ attribute to types.GenericAlias. Patch by Jelle Zijlstra.

  • gh-88089: Add support for generic typing.NamedTuple.

  • gh-91996: New http.HTTPMethod enum to represent all the available HTTP request methods in a convenient way

  • gh-91984: Modified test strings in to not contain trailing spaces before end of line.

  • gh-91952: Add encoding="locale" support to TextIOWrapper.reconfigure().

  • gh-91954: Add encoding and errors arguments to subprocess.getoutput() and subprocess.getstatusoutput().

  • bpo-47029: Always close the read end of the pipe used by multiprocessing.Queue after the last write of buffered data to the write end of the pipe to avoid BrokenPipeError at garbage collection and at multiprocessing.Queue.close() calls. Patch by Géry Ogam.

  • gh-91928: Add datetime.UTC alias for datetime.timezone.utc.

    Patch by Kabir Kwatra.

  • gh-68966: The mailcap module is now deprecated and will be removed in Python 3.13. See PEP 594 for the rationale and the mimetypes module for an alternative. Patch by Victor Stinner.

  • gh-91401: Provide a way to disable subprocess use of vfork() just in case it is ever needed and document the existing mechanism for posix_spawn().

  • gh-64783: Fix signal.NSIG value on FreeBSD to accept signal numbers greater than 32, like signal.SIGRTMIN and signal.SIGRTMAX. Patch by Victor Stinner.

  • gh-91910: Add missing f prefix to f-strings in error messages from the multiprocessing and asyncio modules.

  • gh-91860: Add typing.dataclass_transform(), implementing PEP 681. Patch by Jelle Zijlstra.

  • gh-91832: Add required attribute to argparse.Action repr output.

  • gh-91827: In the tkinter module add method info_patchlevel() which returns the exact version of the Tcl library as a named tuple similar to sys.version_info.

  • gh-84461: Add --enable-wasm-pthreads to enable pthreads support for WASM builds. Emscripten/node no longer has threading enabled by default. Include additional file systems.

  • gh-91821: Fix unstable test_from_tuple test in

  • gh-91217: Deprecate the xdrlib module.

  • gh-91217: Deprecate the uu module.

  • gh-91760: More strict rules will be applied for numerical group references and group names in regular expressions. For now, a deprecation warning is emitted for group references and group names which will be errors in future Python versions.

  • gh-84461: Add provisional sys._emscripten_info named tuple with build-time and run-time information about Emscripten platform.

  • gh-90623: signal.raise_signal() and os.kill() now check immediately for pending signals. Patch by Victor Stinner.

  • gh-91734: Fix OSS audio support on Solaris.

  • gh-90633: Include the passed value in the exception thrown by typing.assert_never(). Patch by Jelle Zijlstra.

  • gh-91700: Compilation of regular expression containing a conditional expression (?(group)...) now raises an appropriate re.error if the group number refers to not defined group. Previously an internal RuntimeError was raised.

  • gh-91231: Add an optional keyword shutdown_timeout parameter to the multiprocessing.BaseManager constructor. Kill the process if terminate() takes longer than the timeout. Patch by Victor Stinner.

  • gh-91621: Fix typing.get_type_hints() for Patch by Shantanu Jain.

  • gh-90568: Parsing \N escapes of Unicode Named Character Sequences in a regular expression raises now re.error instead of TypeError.

  • gh-91670: Remove deprecated SO config variable in sysconfig.

  • gh-91217: Deprecate the telnetlib module.

  • gh-91217: Deprecate the sunau module.

  • gh-91217: Deprecate the spwd module.

  • gh-91217: Deprecate the sndhdr module, as well as inline needed functionality for email.mime.MIMEAudio.

  • gh-91616: re module, fix fullmatch() mismatch when using Atomic Grouping or Possessive Quantifiers.

  • gh-91217: Deprecate the “pipes” module.

  • gh-91217: Deprecate the ossaudiodev module.

  • bpo-47256: re module, limit the maximum capturing group to 1,073,741,823 in 64-bit build, this increases the depth of backtracking.

  • gh-91217: Deprecate the nis module.

  • gh-91595: Fix the comparison of character and integer inside Tools.gdb.libpython.write_repr(). Patch by Yu Liu.

  • gh-74166: Add option to raise all errors from create_connection() in an ExceptionGroup when it fails to create a connection. The default remains to raise only the last error that had occurred when multiple addresses were tried.

  • gh-91487: Optimize asyncio UDP speed, over 100 times faster when transferring a large file.

  • gh-91575: Update case-insensitive matching in the re module to the latest Unicode version.

  • gh-90622: In concurrent.futures.process.ProcessPoolExecutor disallow the «fork» multiprocessing start method when the new max_tasks_per_child feature is used as the mix of threads+fork can hang the child processes. Default to using the safe «spawn» start method in that circumstance if no mp_context was supplied.

  • gh-89022: In sqlite3, SQLITE_MISUSE result codes are now mapped to InterfaceError instead of ProgrammingError. Also, more accurate exceptions are raised when binding parameters fail. Patch by Erlend E. Aasland.

  • gh-91526: Stop calling os.device_encoding(file.fileno()) in TextIOWrapper. It was complex, never documented, and didn’t work for most cases. (Patch by Inada Naoki.)

  • gh-88116: Change the frame-related functions in the inspect module to return a regular object (that is backwards compatible with the old tuple-like interface) that include the extended PEP 657 position information (end line number, column and end column). The affected functions are: inspect.getframeinfo(), inspect.getouterframes(), inspect.getinnerframes(), inspect.stack() and inspect.trace(). Patch by Pablo Galindo.

  • gh-69093: Add indexing and slicing support to sqlite3.Blob. Patch by Aviv Palivoda and Erlend E. Aasland.

  • gh-69093: Add context manager support to sqlite3.Blob. Patch by Aviv Palivoda and Erlend E. Aasland.

  • gh-91217: Deprecate nntplib.

  • gh-91217: Deprecate msilib.

  • gh-91404: Improve the performance of re matching by using computed gotos (or «threaded code») on supported platforms and removing expensive pointer indirections.

  • gh-91217: Deprecate the imghdr module.

  • gh-91217: Deprecate the crypt module.

  • gh-91276: Make space for longer opcodes in dis output.

  • bpo-47000: Make TextIOWrapper uses locale encoding when encoding="locale" is specified even in UTF-8 mode.

  • gh-91230: warnings.catch_warnings() now accepts arguments for warnings.simplefilter(), providing a more concise way to locally ignore warnings or convert them to errors.

  • gh-91217: Deprecate the chunk module.

  • Add the TCP_CONNECTION_INFO option (available on macOS) to socket.

  • bpo-47260: Fix os.closerange() potentially being a no-op in a Linux seccomp sandbox.

  • bpo-47087: Implement typing.Required and typing.NotRequired (PEP 655). Patch by David Foster and Jelle Zijlstra.

  • bpo-47061: Deprecate cgi and cgitb.

  • bpo-47061: Deprecate audioop.

  • bpo-47000: Add locale.getencoding() to get the current locale encoding. It is similar to locale.getpreferredencoding(False) but ignores the Python UTF-8 Mode.

  • bpo-42012: Add wsgiref.types, containing WSGI-specific types for static type checking.

  • bpo-47227: Suppress expression chaining for more re parsing errors.

  • bpo-47211: Remove undocumented and never working function re.template() and flag re.TEMPLATE. This was later reverted in 3.11.0b2 and deprecated instead.

  • bpo-47135: decimal.localcontext() now accepts context attributes via keyword arguments

  • bpo-43323: Fix errors in the email module if the charset itself contains undecodable/unencodable characters.

  • bpo-46841: Disassembly of quickened code.

  • bpo-46681: Forward gzip.compress() compresslevel to zlib.

  • bpo-45100: Add typing.get_overloads() and typing.clear_overloads(). Patch by Jelle Zijlstra.

  • bpo-44807: typing.Protocol no longer silently replaces __init__() methods defined on subclasses. Patch by Adrian Garcia Badaracco.

  • bpo-46787: Fix concurrent.futures.ProcessPoolExecutor exception memory leak

  • bpo-46720: Add support for path-like objects to multiprocessing.set_executable() for Windows to be on a par with Unix-like systems. Patch by Géry Ogam.

  • bpo-46696: Add SO_INCOMING_CPU constant to socket.

  • bpo-46053: Fix OSS audio support on NetBSD.

  • bpo-45639: image/avif and image/webp were added to mimetypes.

  • bpo-46285: Add command-line option -p/--protocol to module http.server which specifies the HTTP version to which the server is conformant (HTTP/1.1 conformant servers can now be run from the command-line interface of module http.server). Patch by Géry Ogam.

  • bpo-44791: Accept ellipsis as the last argument of typing.Concatenate.

  • bpo-46547: Remove variables leaking into pydoc.Helper class namespace.

  • bpo-46415: Fix ipaddress.ip_{address,interface,network} raising TypeError instead of ValueError if given invalid tuple as address parameter.

  • bpo-46075: CookieJar with DefaultCookiePolicy now can process cookies from localhost with domain=localhost explicitly specified in Set-Cookie header.

  • bpo-45995: Add a «z» option to the string formatting specification that coerces negative zero floating-point values to positive zero after rounding to the format precision. Contributed by John Belmonte.

  • bpo-26175: Fully implement the io.BufferedIOBase or io.TextIOBase interface for tempfile.SpooledTemporaryFile objects. This lets them work correctly with higher-level layers (like compression modules). Patch by Carey Metcalfe.

  • bpo-45138: Fix a regression in the sqlite3 trace callback where bound parameters were not expanded in the passed statement string. The regression was introduced in Python 3.10 by bpo-40318. Patch by Erlend E. Aasland.

  • bpo-44863: Allow TypedDict subclasses to also include Generic as a base class in class based syntax. Thereby allowing the user to define a generic TypedDict, just like a user-defined generic but with TypedDict semantics.

  • bpo-44587: Fix BooleanOptionalAction to not automatically add a default string. If a default string is desired, use a formatter to add it.

  • bpo-43827: All positional-or-keyword parameters to ABCMeta.__new__ are now positional-only to avoid conflicts with keyword arguments to be passed to __init_subclass__().

  • bpo-43218: Prevent creation of a venv whose path contains the PATH separator. This could affect the usage of the activate script. Patch by Dustin Rodrigues.

  • bpo-38435: Add a process_group parameter to subprocess.Popen to help move more things off of the unsafe preexec_fn parameter.

  • bpo-42066: Fix cookies getting sorted in CookieJar.__iter__() which is an extra behavior and not mentioned in RFC 2965 or Netscape cookie protocol. Now the cookies in CookieJar follows the order of the Set-Cookie header. Patch by Iman Kermani.

  • bpo-40617: Add create_window_function() to sqlite3.Connection for creating aggregate window functions. Patch by Erlend E. Aasland.

  • bpo-40676: Convert csv to use Argument Clinic for csv.field_size_limit(), csv.get_dialect(), csv.unregister_dialect() and csv.list_dialects().

  • bpo-39716: Raise an ArgumentError when the same subparser name is added twice to an argparse.ArgumentParser. This is consistent with the (default) behavior when the same option string is added twice to an ArgumentParser.

  • bpo-36073: Raise ProgrammingError instead of segfaulting on recursive usage of cursors in sqlite3 converters. Patch by Sergey Fedoseev.

  • bpo-34975: Adds a start_tls() method to StreamWriter, which upgrades the connection with TLS using the given SSLContext.

  • bpo-22276: Path methods glob() and rglob() return only directories if pattern ends with a pathname components separator (/ or sep). Patch by Eisuke Kawashima.

  • bpo-24905: Add blobopen() to sqlite3.Connection. sqlite3.Blob allows incremental I/O operations on blobs. Patch by Aviv Palivoda and Erlend E. Aasland.



  • gh-92169: Use warnings_helper.import_deprecated() to import deprecated modules uniformly in tests. Patch by Hugo van Kemenade.

  • gh-84461: When multiprocessing is enabled, libregrtest can now use a Python executable other than sys.executable via the --python flag.

  • gh-91904: Fix initialization of PYTHONREGRTEST_UNICODE_GUARD which prevented running regression tests on non-UTF-8 locale.

  • gh-91752: Added @requires_zlib to test.test_tools.test_freeze.TestFreeze.

  • gh-91607: Fix test_concurrent_futures to test the correct multiprocessing start method context in several cases where the test logic mixed this up.

  • bpo-40280: Threading tests are now skipped on WASM targets without pthread support.

  • bpo-47109: Test for ctypes.macholib.dyld, ctypes.macholib.dylib, and ctypes.macholib.framework are brought from manual pre-unittest times to ctypes.test location and structure. Patch by Oleg Iarygin.

  • bpo-29890: Add tests for ipaddress.IPv4Interface and ipaddress.IPv6Interface construction with tuple arguments. Original patch and tests by louisom.


  • gh-89452: gdbm-compat is now preferred over ndbm if both are available on the system. This allows avoiding the problematic ndbm.h on macOS.

  • gh-91731: Python is now built with -std=c11 compiler option, rather than -std=c99. Patch by Victor Stinner.

  • bpo-47152: Add script and make target for generating sre_constants.h.

  • bpo-47103: Windows PGInstrument builds now copy a required DLL into the output directory, making it easier to run the profile stage of a PGO build.


  • bpo-46907: Update Windows installer to use SQLite 3.38.3.

  • bpo-47239: Fixed –list and –list-paths output for Lanzador de Python para Windows when used in an active virtual environment.

  • bpo-46907: Update Windows installer to use SQLite 3.38.2.

  • bpo-46785: Fix race condition between os.stat() and unlinking a file on Windows, by using errors codes returned by FindFirstFileW() when appropriate in win32_xstat_impl.

  • bpo-40859: Update Windows build to use xz-5.2.5


  • bpo-46907: Update macOS installer to SQLite 3.38.4.


  • gh-91583: Fix regression in the code generated by Argument Clinic for functions with the defining_class parameter.

  • gh-91575: Add script Tools/scripts/ and the make target regen-re for generating additional data for case-insensitive matching according to the current Unicode version.

  • gh-91551: Remove the ancient Pynche color editor. It has moved to


Python 3.11.0 alpha 7

Release date: 2022-04-05

Core and Builtins

  • bpo-47212: Raise IndentationError instead of SyntaxError for a bare except with no following indent. Improve SyntaxError locations for an un-parenthesized generator used as arguments. Patch by Matthieu Dartiailh.

  • bpo-47186: Replace JUMP_IF_NOT_EG_MATCH by CHECK_EG_MATCH + jump.

  • bpo-47176: Emscripten builds cannot handle signals in the usual way due to platform limitations. Python can now handle signals. To use, set Module.Py_EmscriptenSignalBuffer to be a single byte SharedArrayBuffer and set Py_EMSCRIPTEN_SIGNAL_HANDLING to 1. Writing a number into the SharedArrayBuffer will cause the corresponding signal to be raised into the Python thread.

  • bpo-47186: Replace JUMP_IF_NOT_EXC_MATCH by CHECK_EXC_MATCH + jump.

  • bpo-47120: Replace the absolute jump opcode JUMP_NO_INTERRUPT by the relative JUMP_BACKWARD_NO_INTERRUPT.

  • bpo-46841: Avoid unnecessary allocations when comparing code objects.

  • bpo-47182: Fix a crash when using a named unicode character like "\N{digit nine}" after the main interpreter has been initialized a second time.

  • bpo-47162: WebAssembly cannot deal with bad function pointer casts (different count or types of arguments). Python can now use call trampolines to mitigate the problem. Define PY_CALL_TRAMPOLINE to enable call trampolines.

  • bpo-46775: Some Windows system error codes(>= 10000) are now mapped into the correct errno and may now raise a subclass of OSError. Patch by Dong-hee Na.

  • bpo-47129: Improve error messages in f-string syntax errors concerning empty expressions.

  • bpo-47117: Fix a crash if we fail to decode characters in interactive mode if the tokenizer buffers are uninitialized. Patch by Pablo Galindo.

  • bpo-47127: Speed up calls to c functions with keyword arguments by 25% with specialization. Patch by Kumar Aditya.

  • bpo-47120: Replaced JUMP_ABSOLUTE by the relative jump JUMP_BACKWARD.

  • bpo-42197: PyFrame_FastToLocalsWithError() and PyFrame_LocalsToFast() are no longer called during profiling nor tracing. C code can access the f_locals attribute of PyFrameObject by calling PyFrame_GetLocals().

  • bpo-47070: Improve performance of array_inplace_repeat by reducing the number of invocations of memcpy. Refactor the repeat and inplace repeat methods of array, bytes, bytearray and unicodeobject to use the common _PyBytes_Repeat.

  • bpo-47053: Reduce de-optimization in the specialized BINARY_OP_INPLACE_ADD_UNICODE opcode.

  • bpo-47045: Remove the f_state field from the _PyInterpreterFrame struct. Add the owner field to the _PyInterpreterFrame struct to make ownership explicit to simplify clearing and deallocing frames and generators.

  • bpo-46968: Check for the existence of the «sys/auxv.h» header in faulthandler to avoid compilation problems in systems where this header doesn’t exist. Patch by Pablo Galindo

  • bpo-46329: Use low bit of LOAD_GLOBAL to indicate whether to push a NULL before the global. Helps streamline the call sequence a bit.

  • bpo-46841: Quicken bytecode in-place by storing it as part of the corresponding PyCodeObject.

  • bpo-47012: Speed up iteration of bytes and bytearray by 30%. Patch by Kumar Aditya.

  • bpo-47009: Improved the performance of list.append() and list comprehensions by optimizing for the common case, where no resize is needed. Patch by Dennis Sweeney.

  • bpo-47005: Improve performance of bytearray_repeat and bytearray_irepeat by reducing the number of invocations of memcpy.

  • bpo-46829: Deprecate passing a message into asyncio.Future.cancel() and asyncio.Task.cancel()

  • bpo-46993: Speed up bytearray creation from list and tuple by 40%. Patch by Kumar Aditya.

  • bpo-39829: Removed the __len__() call when initializing a list and moved initializing to list_extend. Patch by Jeremiah Pascual.

  • bpo-46944: Speed up throwing exception in generator with METH_FASTCALL calling convention. Patch by Kumar Aditya.

  • bpo-46841: Modify STORE_SUBSCR to use an inline cache entry (rather than its oparg) as an adaptive counter.

  • bpo-46841: Use inline caching for PRECALL and CALL, and remove the internal machinery for managing the (now unused) non-inline caches.

  • bpo-46881: Statically allocate and initialize the latin1 characters.

  • bpo-46838: Improve syntax errors for incorrect function definitions. Patch by Pablo Galindo

  • bpo-43721: Fix docstrings of getter, setter, and deleter to clarify that they create a new copy of the property.

  • bpo-43224: Make grammar changes required for PEP 646.


  • bpo-47208: Allow vendors to override CTYPES_MAX_ARGCOUNT.

  • bpo-23689: re module: fix memory leak when a match is terminated by a signal or memory allocation failure. Patch by Ma Lin.

  • bpo-47167: Allow overriding a future compliance check in asyncio.Task.

  • bpo-47151: When subprocess tries to use vfork, it now falls back to fork if vfork returns an error. This allows use in situations where vfork isn’t allowed by the OS kernel.

  • bpo-47152: Convert the re module into a package. Deprecate modules sre_compile, sre_constants and sre_parse.

  • bpo-4833: Add ZipFile.mkdir()

  • bpo-27929: Fix asyncio.loop.sock_connect() to only resolve names for socket.AF_INET or socket.AF_INET6 families. Resolution may not make sense for other families, like socket.AF_BLUETOOTH and socket.AF_UNIX.

  • bpo-14265: Adds the fully qualified test name to unittest output

  • bpo-47061: Deprecate the aifc module.

  • bpo-39622: Handle Ctrl+C in asyncio programs to interrupt the main task.

  • bpo-47101: hashlib.algorithms_available now lists only algorithms that are provided by activated crypto providers on OpenSSL 3.0. Legacy algorithms are not listed unless the legacy provider has been loaded into the default OSSL context.

  • bpo-47099: All URLError exception messages raised in urllib.request.URLopener now contain a colon between ftp error and the rest of the message. Previously, open_ftp() missed the colon. Patch by Oleg Iarygin.

  • bpo-47099: Exception chaining is changed from Exception.with_traceback()/sys.exc_info() to PEP 3134. Patch by Oleg Iarygin.

  • bpo-47095: hashlib’s internal _blake2 module now prefers libb2 from over Python’s vendored copy of blake2.

  • bpo-47098: The Keccak Code Package for hashlib’s internal _sha3 module has been replaced with tiny_sha3. The module is used as fallback when Python is built without OpenSSL.

  • bpo-47088: Implement typing.LiteralString, part of PEP 675. Patch by Jelle Zijlstra.

  • bpo-42885: Optimize, re.split(), re.findall(), re.finditer() and re.sub() for regular expressions starting with \A or ^.

  • bpo-23691: Protect the re.finditer() iterator from re-entering.

  • bpo-47067: Optimize calling GenericAlias objects by using PEP 590 vectorcall and by replacing PyObject_SetAttrString with PyObject_SetAttr.

  • bpo-28080: Add the metadata_encoding parameter in the zipfile.ZipFile constructor and the --metadata-encoding option in the zipfile CLI to allow reading zipfiles using non-standard codecs to encode the filenames within the archive.

  • bpo-47000: Make io.text_encoding() returns «utf-8» when UTF-8 mode is enabled.

  • bpo-42369: Fix thread safety of zipfile._SharedFile.tell() to avoid a «zipfile.BadZipFile: Bad CRC-32 for file» exception when reading a ZipFile from multiple threads.

  • bpo-38256: Fix binascii.crc32() when it is compiled to use zlib’c crc32 to work properly on inputs 4+GiB in length instead of returning the wrong result. The workaround prior to this was to always feed the function data in increments smaller than 4GiB or to just call the zlib module function.

    We also have binascii.crc32() release the GIL when computing on larger inputs as zlib.crc32() and hashlib do.

    This also boosts performance on Windows as it now uses the zlib crc32 implementation for binascii.crc32() for a 2-3x speedup.

    That the stdlib has a crc32 API in two modules is a known historical oddity. This moves us closer to a single implementation behind them.

  • bpo-47066: Global inline flags (e.g. (?i)) can now only be used at the start of the regular expressions. Using them not at the start of expression was deprecated since Python 3.6.

  • bpo-39394: A warning about inline flags not at the start of the regular expression now contains the position of the flag.

  • bpo-433030: Add support of atomic grouping ((?>...)) and possessive quantifiers (*+, ++, ?+, {m,n}+) in regular expressions.

  • bpo-47062: Implement asyncio.Runner context manager.

  • bpo-46382: dataclass() slots=True now correctly omits slots already defined in base classes. Patch by Arie Bovenberg.

  • bpo-47057: Use FASTCALL convention for FutureIter.throw()

  • bpo-47061: Deprecate the various modules listed by PEP 594:

    aifc, asynchat, asyncore, audioop, cgi, cgitb, chunk, crypt, imghdr, msilib, nntplib, nis, ossaudiodev, pipes, smtpd, sndhdr, spwd, sunau, telnetlib, uu, xdrlib

  • bpo-34790: Remove passing coroutine objects to asyncio.wait().

  • bpo-47039: Normalize repr() of asyncio future and task objects.

  • bpo-2604: Fix bug where doctests using globals would fail when run multiple times.

  • bpo-45150: Add hashlib.file_digest() helper for efficient hashing of file object.

  • bpo-34861: Made cumtime the default sorting key for cProfile

  • bpo-45997: Fix asyncio.Semaphore re-aquiring FIFO order.

  • bpo-47022: The asynchat, asyncore and smtpd modules have been deprecated since at least Python 3.6. Their documentation and deprecation warnings and have now been updated to note they will removed in Python 3.12 (PEP 594).

  • bpo-43253: Fix a crash when closing transports where the underlying socket handle is already invalid on the Proactor event loop.

  • bpo-40280: now passes NULL to select for each empty fdset.

  • bpo-47004: Apply bugfixes from importlib_metadata 4.11.3, including bugfix for EntryPoint.extras, which was returning match objects and not the extras strings.

  • bpo-46998: Allow subclassing of typing.Any. Patch by Shantanu Jain.

  • bpo-46995: Deprecate missing asyncio.Task.set_name() for third-party task implementations, schedule making it mandatory in Python 3.13.

  • bpo-46994: Accept explicit contextvars.Context in asyncio.create_task() and asyncio.loop.create_task().

  • bpo-46981: typing.get_args(typing.Tuple[()]) now returns () instead of ((),).

  • bpo-46968: Add os.sysconf_names['SC_MINSIGSTKSZ'].

  • bpo-46985: Upgrade pip wheel bundled with ensurepip (pip 22.0.4)

  • bpo-46968: faulthandler: On Linux 5.14 and newer, dynamically determine size of signal handler stack size CPython allocates using getauxval(AT_MINSIGSTKSZ). This changes allows for Python extension’s request to Linux kernel to use AMX_TILE instruction set on Sapphire Rapids Xeon processor to succeed, unblocking use of the ISA in frameworks.

  • bpo-46917: The math.nan value is now always available. Patch by Victor Stinner.

  • bpo-46955: Expose asyncio.base_events.Server as asyncio.Server. Patch by Stefan Zabka.

  • bpo-23325: The signal module no longer assumes that SIG_IGN and SIG_DFL are small int singletons.

  • bpo-46932: Update bundled libexpat to 2.4.7

  • bpo-46933: The pwd module is now optional. os.path.expanduser() returns the path when the pwd module is not available.

  • bpo-40059: PEP 680, the tomllib module. Adds support for parsing TOML.

  • bpo-464471: asyncio.timeout() and asyncio.timeout_at() context managers added. Patch by Tin Tvrtković and Andrew Svetlov.

  • bpo-46805: Added raw datagram socket functions for asyncio: sock_sendto(), sock_recvfrom() and sock_recvfrom_into().

  • bpo-46644: No longer require valid typeforms to be callable. This allows typing.Annotated to wrap typing.ParamSpecArgs and dataclasses.InitVar. Patch by Gregory Beauregard.

  • bpo-46581: Brings ParamSpec propagation for GenericAlias in line with Concatenate (and others).

  • bpo-45413: Define posix_venv and nt_venv sysconfig installation schemes to be used for bootstrapping new virtual environments. Add venv sysconfig installation scheme to get the appropriate one of the above. The schemes are identical to the pre-existing posix_prefix and nt install schemes. The venv module now uses the venv scheme to create new virtual environments instead of hardcoding the paths depending only on the platform. Downstream Python distributors customizing the posix_prefix or nt install scheme in a way that is not compatible with the install scheme used in virtual environments are encouraged not to customize the venv schemes. When Python itself runs in a virtual environment, sysconfig.get_default_scheme() and sysconfig.get_preferred_scheme() with key="prefix" returns venv.

  • bpo-43224: Implement support for PEP 646 in

  • bpo-43224: Allow unpacking types.GenericAlias objects, e.g. *tuple[int, str].

  • bpo-46557: Warnings captured by the logging module are now logged without a format string to prevent systems that group logs by the msg argument from grouping captured warnings together.

  • bpo-41370: typing.get_type_hints() now supports evaluating strings as forward references in PEP 585 generic aliases.

  • bpo-46607: Add DeprecationWarning to LegacyInterpolation, deprecated in the docstring since Python 3.2. Will be removed in Python 3.13. Use BasicInterpolation or ExtendedInterpolation instead.

  • bpo-26120: pydoc now excludes __future__ imports from the module’s data items.

  • bpo-46480: Add typing.assert_type(). Patch by Jelle Zijlstra.

  • bpo-46421: Fix a unittest issue where if the command was invoked as python -m unittest and the filename(s) began with a dot (.), a ValueError is returned.

  • bpo-46245: Add optional parameter dir_fd in shutil.rmtree().

  • bpo-22859: usageExit() is marked deprecated, to be removed in 3.13.

  • bpo-46170: Improve the error message when you try to subclass an instance of typing.NewType.

  • bpo-40296: Fix supporting generic aliases in pydoc.

  • bpo-20392: Fix inconsistency with uppercase file extensions in MimeTypes.guess_type(). Patch by Kumar Aditya.

  • bpo-46030: Add LOCAL_CREDS, LOCAL_CREDS_PERSISTENT and SCM_CREDS2 FreeBSD constants to the socket module.

  • bpo-44439: Fix .write() method of a member file in ZipFile, when the input data is an object that supports the buffer protocol, the file length may be wrong.

  • bpo-45171: Fix handling of the stacklevel argument to logging functions in the logging module so that it is consistent across all logging functions and, as advertised, similar to the stacklevel argument used in warn().

  • bpo-24959: Fix bug where unittest sometimes drops frames from tracebacks of exceptions raised in tests.

  • bpo-44859: Raise more accurate and PEP 249 compatible exceptions in sqlite3.

  • bpo-44493: Add missing terminated NUL in sockaddr_un’s length

    This was potentially observable when using non-abstract AF_UNIX datagram sockets to processes written in another programming language.

  • bpo-41930: Add serialize() and deserialize() support to sqlite3. Patch by Erlend E. Aasland.

  • bpo-33178: Added ctypes.BigEndianUnion and ctypes.LittleEndianUnion classes, as originally documented in the library docs but not yet implemented.

  • bpo-43352: Add an Barrier object in synchronization primitives of asyncio Lib in order to be consistant with Barrier from threading and multiprocessing libs*

  • bpo-35859: re module, fix a few bugs about capturing group. In rare cases, capturing group gets an incorrect string. Patch by Ma Lin.




  • bpo-40280: Add configure option --enable-wasm-dynamic-linking to enable dlopen and MAIN_MODULE / SIDE_MODULE on wasm32-emscripten.

  • bpo-46023: makesetup now detects and skips all duplicated module definitions. The first entry wins.

  • bpo-40280: Add SOABI wasm32-emscripten for Emscripten and wasm32-wasi for WASI on 32bit WASM as well as wasm64 counter parts.

  • bpo-47032: Ensure Windows install builds fail correctly with a non-zero exit code when part of the build fails.

  • bpo-47024: Update OpenSSL to 1.1.1n for macOS installers and all Windows builds.

  • bpo-46996: The tkinter package now requires Tcl/Tk version 8.5.12 or newer.

  • bpo-46973: Add regen-configure make target to regenerate configure script with Christian’s container image

  • bpo-46917: Building Python now requires support of IEEE 754 floating point numbers. Patch by Victor Stinner.

  • bpo-45774: configure now verifies that all SQLite C APIs needed for the sqlite3 extension module are found.


  • bpo-47194: Update zlib to v1.2.12 to resolve CVE-2018-25032.

  • bpo-47171: Enables installing the py.exe launcher on Windows ARM64.

  • bpo-46566: Upgraded Lanzador de Python para Windows to support a new -V:company/tag argument for full PEP 514 support and to detect ARM64 installs. The -64 suffix on arguments is deprecated, but still selects any non-32-bit install. Setting PYLAUNCHER_ALLOW_INSTALL and specifying a version that is not installed will attempt to install the requested version from the Microsoft Store.

  • bpo-47086: The installer for Windows now includes documentation as loose HTML files rather than a single compiled .chm file.

  • bpo-46907: Update Windows installer to use SQLite 3.38.1.

  • bpo-44549: Update bzip2 to 1.0.8 in Windows builds to mitigate CVE-2016-3189 and CVE-2019-12900

  • bpo-46948: Prevent CVE-2022-26488 by ensuring the Add to PATH option in the Windows installer uses the correct path when being repaired.


  • bpo-46890: Fix a regression in the setting of sys._base_executable in framework builds, and thereby fix a regression in venv virtual environments with such builds.

  • bpo-46907: Update macOS installer to SQLite 3.38.1.


  • bpo-40280: Replace Emscripten’s limited shell with Katie Bell’s browser-ui REPL from python-wasm project.


  • bpo-40421: Add PyFrame_GetBuiltins, PyFrame_GetGenerator and PyFrame_GetGlobals C-API functions to access frame object attributes safely from C code.

  • bpo-46850: Move the private _PyFrameEvalFunction type, and private _PyInterpreterState_GetEvalFrameFunc() and _PyInterpreterState_SetEvalFrameFunc() functions to the internal C API. The _PyFrameEvalFunction callback function type now uses the _PyInterpreterFrame type which is part of the internal C API. Patch by Victor Stinner.

  • bpo-46850: Move the private undocumented _PyEval_EvalFrameDefault() function to the internal C API. The function now uses the _PyInterpreterFrame type which is part of the internal C API. Patch by Victor Stinner.

  • bpo-46850: Remove the private undocumented function _PyEval_CallTracing() from the C API. Call the public sys.call_tracing() function instead. Patch by Victor Stinner.

  • bpo-46850: Remove the private undocumented function _PyEval_GetCoroutineOriginTrackingDepth() from the C API. Call the public sys.get_coroutine_origin_tracking_depth() function instead. Patch by Victor Stinner.

  • bpo-46850: Remove the following private undocumented functions from the C API:

    • _PyEval_GetAsyncGenFirstiter()

    • _PyEval_GetAsyncGenFinalizer()

    • _PyEval_SetAsyncGenFirstiter()

    • _PyEval_SetAsyncGenFinalizer()

    Call the public sys.get_asyncgen_hooks() and sys.set_asyncgen_hooks() functions instead. Patch by Victor Stinner.

  • bpo-46987: Remove private functions _PySys_GetObjectId() and _PySys_SetObjectId(). Patch by Dong-hee Na.

  • bpo-46906: Add new functions to pack and unpack C double (serialize and deserialize): PyFloat_Pack2(), PyFloat_Pack4(), PyFloat_Pack8(), PyFloat_Unpack2(), PyFloat_Unpack4() and PyFloat_Unpack8(). Patch by Victor Stinner.

Python 3.11.0 alpha 6

Release date: 2022-03-07

Core and Builtins

  • bpo-46940: Avoid overriding AttributeError metadata information for nested attribute access calls. Patch by Pablo Galindo.

  • bpo-46927: Include the type’s name in the error message for subscripting non-generic types.

  • bpo-46921: Support vectorcall for super(). Patch by Ken Jin.

  • bpo-46841: Fix incorrect handling of inline cache entries when specializing BINARY_OP.

  • bpo-46841: Use an oparg to simplify the construction of helpful error messages in GET_AWAITABLE.

  • bpo-46903: Make sure that str subclasses can be used as attribute names for instances with virtual dictionaries. Fixes regression in 3.11alpha

  • bpo-46841: Add more detailed specialization failure stats for COMPARE_OP followed by EXTENDED_ARG.

  • bpo-46891: Fix bug introduced during 3.11alpha where subclasses of types.ModuleType with __slots__ were not initialized correctly, resulting in an interpreter crash.

  • bpo-46841: Use inline caching for LOAD_ATTR, LOAD_METHOD, and STORE_ATTR.

  • bpo-46841: Use inline cache for BINARY_SUBSCR.

  • bpo-46841: Use inline caching for COMPARE_OP.

  • bpo-46864: Deprecate PyBytesObject.ob_shash. It will be removed in Python 3.13.

  • bpo-46841: Use inline caching for UNPACK_SEQUENCE.

  • bpo-46845: Reduces dict size by removing hash value from hash table when all inserted keys are Unicode. For example, sys.getsizeof(dict.fromkeys("abcdefg")) becomes 272 bytes from 352 bytes on 64bit platform.

  • bpo-46841: Use inline cache for LOAD_GLOBAL.

  • bpo-46852: Rename the private undocumented float.__set_format__() method to float.__setformat__() to fix a typo introduced in Python 3.7. The method is only used by test_float. Patch by Victor Stinner.

  • bpo-46852: Remove the undocumented private float.__set_format__() method, previously known as float.__setformat__() in Python 3.7. Its docstring said: «You probably don’t want to use this function. It exists mainly to be used in Python’s test suite.» Patch by Victor Stinner.

  • bpo-40116: Fix regression that dict.update(other) may don’t respect iterate order of other when other is key sharing dict.

  • bpo-46712: Share global string identifiers in deep-frozen modules.

  • bpo-46430: Fix memory leak in interned strings of deep-frozen modules.

  • bpo-46841: Store BINARY_OP caches inline using a new CACHE instruction.

  • bpo-45107: Specialize LOAD_METHOD for instances with a dict.

  • bpo-44337: Reduce the memory usage of specialized LOAD_ATTR and STORE_ATTR instructions.

  • bpo-46729: Add number of sub-exceptions to BaseException.__str__().

  • bpo-45885: Don’t un-adapt COMPARE_OP when collecting specialization stats.

  • bpo-46329: Fix specialization stats gathering for PRECALL instructions.

  • bpo-46794: Bump up the libexpat version into 2.4.6

  • bpo-46823: Implement a specialized combined opcode LOAD_FAST__LOAD_ATTR_INSTANCE_VALUE. Patch by Dennis Sweeney.

  • bpo-46820: Fix parsing a numeric literal immediately (without spaces) followed by «not in» keywords, like in 1not in x. Now the parser only emits a warning, not a syntax error.

  • bpo-46329: Move KW_NAMES before PRECALL instruction in call sequence. Change operand of CALL to match PRECALL for easier specialization.

  • bpo-46808: Remove the NEXT_BLOCK macro from compile.c, and make the compiler automatically generate implicit blocks when they are needed.

  • bpo-46329: Add PUSH_NULL instruction. This is used as a prefix when evaluating a callable, so that the stack has the same shape for methods and other calls. PRECALL_FUNCTION and PRECALL_METHOD are merged into a single PRECALL instruction.

    There is no change in semantics.

  • bpo-46762: Fix an assert failure in debug builds when a “<”, “>”, or “=” is the last character in an f-string that’s missing a closing right brace.

  • bpo-46730: Message of AttributeError caused by getting, setting or deleting a property without the corresponding function now mentions that the attribute is in fact a property and also specifies type of the class that it belongs to.

  • bpo-46724: Make sure that all backwards jumps use the JUMP_ABSOLUTE instruction, rather than JUMP_FORWARD with an argument of (2**32)+offset.

  • bpo-46732: Correct the docstring for the __bool__() method. Patch by Jelle Zijlstra.

  • bpo-46072: Add more detailed specialization failure statistics for BINARY_OP.

  • bpo-46707: Avoid potential exponential backtracking when producing some syntax errors involving lots of brackets. Patch by Pablo Galindo.

  • bpo-46323: ctypes now allocates memory on the stack instead of on the heap to pass arguments while calling a Python callback function. Patch by Dong-hee Na.

  • bpo-45923: Add a quickened form of RESUME that skips quickening checks.

  • bpo-46702: Specialize UNPACK_SEQUENCE for tuple and list unpackings.

  • bpo-46072: Opcode pair stats are now gathered with --enable-pystats. Defining DYNAMIC_EXECUTION_PROFILE or DXPAIRS no longer has any effect.

  • bpo-46675: Allow more than 16 items in a split dict before it is combined. The limit is now 254.

  • bpo-40479: Add a missing call to va_end() in Modules/_hashopenssl.c.

  • bpo-46323: Use PyObject_Vectorcall() while calling ctypes callback function. Patch by Dong-hee Na.

  • bpo-46615: When iterating over sets internally in setobject.c, acquire strong references to the resulting items from the set. This prevents crashes in corner-cases of various set operations where the set gets mutated.

  • bpo-45828: The bytecode compiler now attempts to apply runtime stack manipulations at compile-time (whenever it is feasible to do so).

  • bpo-30496: Fixed a minor portability issue in the implementation of PyLong_FromLong(), and added a fast path for single-digit integers to PyLong_FromLongLong().



  • bpo-42238: Doc/tools/ has moved to its own repository and is now packaged on PyPI as sphinx-lint.


  • bpo-46913: Fix test_faulthandler.test_sigfpe() if Python is built with undefined behavior sanitizer (UBSAN): disable UBSAN on the faulthandler_sigfpe() function. Patch by Victor Stinner.

  • bpo-46760: Remove bytecode offsets from expected values in test.test_dis module. Reduces the obstacles to modifying the VM or compiler.

  • bpo-46708: Prevent default asyncio event loop policy modification warning after test_asyncio execution.

  • bpo-46678: The function make_legacy_pyc in Lib/test/support/ no longer fails when PYTHONPYCACHEPREFIX is set to a directory on a different device from where tempfiles are stored.

  • bpo-46623: Skip test_pair() and test_speech128() of test_zlib on s390x since they fail if zlib uses the s390x hardware accelerator. Patch by Victor Stinner.


  • bpo-46860: Respect --with-suffix when building on case-insensitive file systems.

  • bpo-46656: Building Python now requires a C11 compiler. Optional C11 features are not required. Patch by Victor Stinner.

  • bpo-46656: Building Python now requires support for floating point Not-a-Number (NaN): remove the Py_NO_NAN macro. Patch by Victor Stinner.

  • bpo-46640: Building Python now requires a C99 <math.h> header file providing a NAN constant, or the __builtin_nan() built-in function. Patch by Victor Stinner.

  • bpo-46608: Exclude marshalled-frozen data if deep-freezing to save 300 KB disk space. This includes adding a new is_package field to _frozen. Patch by Kumar Aditya.

  • bpo-40280: Fix wasm32-emscripten test failures and platform issues. - Disable syscalls that are not supported or don’t work, e.g. wait, getrusage, prlimit, mkfifo, mknod, setres[gu]id, setgroups. - Use fd_count to cound open fds. - Add more checks for subprocess and fork. - Add workarounds for missing _multiprocessing and failing socket.accept(). - Enable bzip2. - Disable large file support. - Disable signal.alarm.

  • bpo-46430: Intern strings in deep-frozen modules. Patch by Kumar Aditya.


  • bpo-46744: The default all users install directory for ARM64 is now under the native Program Files folder, rather than Program Files (Arm) which is intended for ARM (32-bit) files.

  • bpo-46567: Adds Tcl and Tk support for Windows ARM64. This also adds IDLE to the installation.

  • bpo-46638: Ensures registry virtualization is consistently disabled. For 3.10 and earlier, it remains enabled (some registry writes are protected), while for 3.11 and later it is disabled (registry modifications affect all applications).


  • bpo-46630: Make query dialogs on Windows start with a cursor in the entry box.

  • bpo-45447: Apply IDLE syntax highlighting to pyi files. Patch by Alex Waygood and Terry Jan Reedy.


  • bpo-46748: Python’s public headers no longer import <stdbool.h>, leaving code that embedd/extends Python free to define bool, true and false.

  • bpo-46836: Move the PyFrameObject type definition (struct _frame) to the internal C API pycore_frame.h header file. Patch by Victor Stinner.

  • bpo-45459: Rename Include/buffer.h header file to Include/pybuffer.h to avoid conflits with projects having an existing buffer.h header file. Patch by Victor Stinner.

  • bpo-45412: Remove the HAVE_PY_SET_53BIT_PRECISION macro (moved to the internal C API). Patch by Victor Stinner.

  • bpo-46613: Added function PyType_GetModuleByDef(), which allows accesss to module state when a method’s defining class is not available.

Python 3.11.0 alpha 5

Release date: 2022-02-03

Core and Builtins

  • bpo-45773: Remove two invalid «peephole» optimizations from the bytecode compiler.

  • bpo-46564: Do not create frame objects when creating super object. Patch by Kumar Aditya.

  • bpo-45885: Added more fined-grained specialization failure stats regarding the COMPARE_OP bytecode.

  • bpo-44977: The delegation of int() to __trunc__() is now deprecated. Calling int(a) when type(a) implements __trunc__() but not __int__() or __index__() now raises a DeprecationWarning.

  • bpo-46458: Reorder code emitted by the compiler for a try-except block so that the else block’s code immediately follows the try body (without a jump). This is more optimal for the happy path.

  • bpo-46527: Allow passing iterable as a keyword argument to enumerate() again. Patch by Jelle Zijlstra.

  • bpo-46528: Replace several stack manipulation instructions (DUP_TOP, DUP_TOP_TWO, ROT_TWO, ROT_THREE, ROT_FOUR, and ROT_N) with new COPY and SWAP instructions.

  • bpo-46329: Use two or three bytecodes to implement most calls.

    Calls without named arguments are implemented as a sequence of two instructions: PRECALL; CALL. Calls with named arguments are implemented as a sequence of three instructions: PRECALL; KW_NAMES; CALL. There are two different PRECALL instructions: PRECALL_FUNTION and PRECALL_METHOD. The latter pairs with LOAD_METHOD.

    This partition into pre-call and call allows better specialization, and thus better performance ultimately.

    There is no change in semantics.

  • bpo-46503: Fix an assert when parsing some invalid N escape sequences in f-strings.

  • bpo-46431: Improve error message on invalid calls to BaseExceptionGroup.__new__().

  • bpo-46476: Fix memory leak in code objects generated by deepfreeze. Patch by Kumar Aditya.

  • bpo-46481: Speed up calls to weakref.ref.__call__() by using the PEP 590 vectorcall calling convention. Patch by Dong-hee Na.

  • bpo-46417: Fix a race condition on setting a type __bases__ attribute: the internal function add_subclass() now gets the PyTypeObject.tp_subclasses member after calling PyWeakref_NewRef() which can trigger a garbage collection which can indirectly modify PyTypeObject.tp_subclasses. Patch by Victor Stinner.

  • bpo-46417: python -X showrefcount now shows the total reference count after clearing and destroyed the main Python interpreter. Previously, it was shown before. Patch by Victor Stinner.

  • bpo-43683: Add ASYNC_GEN_WRAP opcode to wrap the value to be yielded in async generators. Removes the need to special case async generators in the YIELD_VALUE instruction.

  • bpo-46407: Optimize some modulo operations in Objects/longobject.c. Patch by Jeremiah Vivian.

  • bpo-46409: Add new RETURN_GENERATOR bytecode to make generators. Simplifies calling Python functions in the VM, as they no longer any need to special case generator functions.

    Also add JUMP_NO_INTERRUPT bytecode that acts like JUMP_ABSOLUTE, but does not check for interrupts.

  • bpo-46406: The integer division // implementation has been optimized to better let the compiler understand its constraints. It can be 20% faster on the amd64 platform when dividing an int by a value smaller than 2**30.

  • bpo-46383: Fix invalid signature of _zoneinfo’s module_free function to resolve a crash on wasm32-emscripten platform.

  • bpo-46361: Ensure that «small» integers created by int.from_bytes() and decimal.Decimal are properly cached.

  • bpo-46161: Fix the class building error when the arguments are constants and CALL_FUNCTION_EX is used.

  • bpo-46028: Fixes calculation of sys._base_executable when inside a virtual environment that uses symlinks with different binary names than the base environment provides.

  • bpo-46091: Correctly calculate indentation levels for lines with whitespace character that are ended by line continuation characters. Patch by Pablo Galindo

  • bpo-30512: Add CAN Socket support for NetBSD.

  • bpo-46045: Do not use POSIX semaphores on NetBSD

  • bpo-44024: Improve the exc:TypeError message for non-string second arguments passed to the built-in functions getattr() and hasattr(). Patch by Géry Ogam.


  • bpo-46624: Restore support for non-integer arguments of random.randrange() and random.randint().

  • bpo-46591: Make the IDLE doc URL on the About IDLE dialog clickable.

  • bpo-46565: Remove loop variables that are leaking into modules” namespaces.

  • bpo-46553: In typing.get_type_hints(), support evaluating bare stringified ClassVar annotations. Patch by Gregory Beauregard.

  • bpo-46544: Don’t leak x & uspace intermediate vars in textwrap.TextWrapper.

  • bpo-46487: Add the get_write_buffer_limits method to asyncio.transports.WriteTransport and to the SSL transport.

  • bpo-45173: Note the configparser deprecations will be removed in Python 3.12.

  • bpo-45162: The deprecated unittest APIs removed in 3.11a1 have been temporarily restored to be removed in 3.12 while cleanups in external projects go in.

  • bpo-46539: In typing.get_type_hints(), support evaluating stringified ClassVar and Final annotations inside Annotated. Patch by Gregory Beauregard.

  • bpo-46510: Add missing test for types.TracebackType and types.FrameType. Calculate them directly from the caught exception without calling sys.exc_info().

  • bpo-46491: Allow typing.Annotated to wrap typing.Final and typing.ClassVar. Patch by Gregory Beauregard.

  • bpo-46483: Remove __class_getitem__() from pathlib.PurePath as this class was not supposed to be generic.

  • bpo-46436: Fix command-line option -d/--directory in module http.server which is ignored when combined with command-line option --cgi. Patch by Géry Ogam.

  • bpo-41403: Make mock.patch() raise a TypeError with a relevant error message on invalid arg. Previously it allowed a cryptic AttributeError to escape.

  • bpo-46474: In importlib.metadata.EntryPoint.pattern, avoid potential REDoS by limiting ambiguity in consecutive whitespace.

  • bpo-46474: Removed private method from importlib.metadata.Path. Sync with importlib_metadata 4.10.0.

  • bpo-46470: Remove unused branch from typing._remove_dups_flatten

  • bpo-46469: asyncio generic classes now return types.GenericAlias in __class_getitem__ instead of the same class.

  • bpo-41906: Support passing filter instances in the filters values of handlers and loggers in the dictionary passed to logging.config.dictConfig().

  • bpo-46422: Use dis.Positions in dis.Instruction instead of a regular tuple.

  • bpo-46434: pdb now gracefully handles help when __doc__ is missing, for example when run with pregenerated optimized .pyc files.

  • bpo-43869: Python uses the same time Epoch on all platforms. Add an explicit unit test to ensure that it’s the case. Patch by Victor Stinner.

  • bpo-46414: Add typing.reveal_type(). Patch by Jelle Zijlstra.

  • bpo-40280: subprocess now imports Windows-specific imports when msvcrt module is available, and POSIX-specific imports on all other platforms. This gives a clean exception when _posixsubprocess is not available (e.g. Emscripten browser target).

  • bpo-40066: IntEnum, IntFlag, and StrEnum use the mixed-in type for their str() and format() output.

  • bpo-46316: Optimize pathlib.Path.iterdir() by removing an unnecessary check for special entries.

  • bpo-29688: Document pathlib.Path.absolute() (which has always existed).

  • bpo-43012: The pathlib module’s obsolete and internal _Accessor class has been removed to prepare the terrain for upcoming enhancements to the module.

  • bpo-46258: Speed up math.isqrt() for small positive integers by replacing two division steps with a lookup table.

  • bpo-46242: Improve error message when creating a new enum.Enum type subclassing an existing Enum with _member_names_ using enum.Enum.__call__().

  • bpo-43118: Fix a bug in inspect.signature() that was causing it to fail on some subclasses of classes with a __text_signature__ referencing module globals. Patch by Weipeng Hong.

  • bpo-26552: Fixed case where failing asyncio.ensure_future() did not close the coroutine. Patch by Kumar Aditya.

  • bpo-21987: Fix an issue with tarfile.TarFile.getmember() getting a directory name with a trailing slash.

  • bpo-46124: Update zoneinfo to rely on importlib.resources traversable API.

  • bpo-46103: Now inspect.getmembers() only gets __bases__ attribute from class type. Patch by Weipeng Hong.

  • bpo-46080: Fix exception in argparse help text generation if a argparse.BooleanOptionalAction argument’s default is argparse.SUPPRESS and it has help specified. Patch by Felix Fontein.

  • bpo-44791: Fix substitution of ParamSpec in Concatenate with different parameter expressions. Substitution with a list of types returns now a tuple of types. Substitution with Concatenate returns now a Concatenate with concatenated lists of arguments.


  • bpo-46463: Fixes script used when building the CHM documentation file


  • bpo-43478: Mocks can no longer be provided as the specs for other Mocks. As a result, an already-mocked object cannot be passed to mock.Mock(). This can uncover bugs in tests since these Mock-derived Mocks will always pass certain tests (e.g. isinstance) and builtin assert functions (e.g. assert_called_once_with) will unconditionally pass.

  • bpo-46616: Ensures test_importlib.test_windows cleans up registry keys after completion.

  • bpo-44359: test_ftplib now silently ignores socket errors to prevent logging unhandled threading exceptions. Patch by Victor Stinner.

  • bpo-46600: Fix test_gdb.test_pycfunction() for Python built with clang -Og. Tolerate inlined functions in the gdb traceback. Patch by Victor Stinner.

  • bpo-46542: Fix a Python crash in test_lib2to3 when using Python built in debug mode: limit the recursion limit. Patch by Victor Stinner.

  • bpo-46576: test_peg_generator now disables compiler optimization when testing compilation of its own C extensions to significantly speed up the testing on non-debug builds of CPython.

  • bpo-46542: Fix test_json tests checking for RecursionError: modify these tests to use support.infinite_recursion(). Patch by Victor Stinner.

  • bpo-13886: Skip test_builtin PTY tests on non-ASCII characters if the readline module is loaded. The readline module changes input() behavior, but test_builtin is not intented to test the readline module. Patch by Victor Stinner.

  • bpo-40280: Add decorators to mark tests that require a working os.fork().

  • bpo-40280: Add decorator to mark tests which require working subprocess module or os.spawn*. The wasm32-emscripten platform has no support for processes.

  • bpo-46126: Disable “descriptions” when running tests internally.


  • bpo-46602: Tidied up so that conftest.c is truncated rather than appended. This assists in the case where the “rm” of conftest.c fails to happen between tests. Downstream issues such as a clobbered SOABI can result.

  • bpo-46600: Fix the test checking if the C compiler supports -Og option in the ./configure script to also use -Og on clang which supports it. Patch by Victor Stinner.

  • bpo-38472: Fix GCC detection in when cross-compiling. The C compiler is now run with LC_ALL=C. Previously, the detection failed with a German locale.

  • bpo-46513: configure no longer uses AC_C_CHAR_UNSIGNED macro and pyconfig.h no longer defines reserved symbol __CHAR_UNSIGNED__.

  • bpo-46471: Use global singletons for single byte bytes objects in deepfreeze.

  • bpo-46443: Deepfreeze now uses cached small integers as it saves some space for common small integers.

  • bpo-46429: Merge all deep-frozen files into one for space savings. Patch by Kumar Aditya.

  • bpo-45569: The build now defaults to using 30-bit digits for Python integers. Previously either 15-bit or 30-bit digits would be selected, depending on the platform. 15-bit digits may still be selected using the --enable-big-digits=15 option to the configure script, or by defining PYLONG_BITS_IN_DIGIT in pyconfig.h.

  • bpo-45925: Update Windows installer to use SQLite 3.37.2.

  • bpo-43112: Detect musl libc as a separate SOABI (tagged as linux-musl).


  • bpo-33125: The traditional EXE/MSI based installer for Windows is now available for ARM64

  • bpo-46362: os.path.abspath(«C:CON») is now fixed to return «\.CON», not the same path. The regression was true of all legacy DOS devices such as COM1, LPT1, or NUL.

  • bpo-44934: The installer now offers a command-line only option to add the installation directory to the end of PATH instead of at the start.


  • bpo-45925: Update macOS installer to SQLite 3.37.2.


  • bpo-45296: Clarify close, quit, and exit in IDLE. In the File menu, “Close” and “Exit” are now “Close Window” (the current one) and “Exit” is now “Exit IDLE” (by closing all windows). In Shell, “quit()” and “exit()” mean “close Shell”. If there are no other windows, this also exits IDLE.


  • bpo-40170: Remove the PyHeapType_GET_MEMBERS() macro. It was exposed in the public C API by mistake, it must only be used by Python internally. Use the PyTypeObject.tp_members member instead. Patch by Victor Stinner.

  • bpo-40170: Move _Py_GetAllocatedBlocks() and _PyObject_DebugMallocStats() private functions to the internal C API. Patch by Victor Stinner.

  • bpo-46433: The internal function _PyType_GetModuleByDef now correctly handles inheritance patterns involving static types.

  • bpo-45459: Py_buffer and various Py_buffer related functions are now part of the limited API and stable ABI.

  • bpo-14916: Fixed bug in the tokenizer that prevented PyRun_InteractiveOne from parsing from the provided FD.

Python 3.11.0 alpha 4

Release date: 2022-01-13

Core and Builtins

  • bpo-46070: Py_EndInterpreter() now explicitly untracks all objects currently tracked by the GC. Previously, if an object was used later by another interpreter, calling PyObject_GC_UnTrack() on the object crashed if the previous or the next object of the PyGC_Head structure became a dangling pointer. Patch by Victor Stinner.

  • bpo-46347: Fix memory leak in PyEval_EvalCodeEx.

  • bpo-46339: Fix a crash in the parser when retrieving the error text for multi-line f-strings expressions that do not start in the first line of the string. Patch by Pablo Galindo

  • bpo-46331: Do not set line number of instruction storing doc-string. Fixes regression introduced in 3.11 alpha.

  • bpo-46314: Remove spurious «call» event when creating a lambda function that was accidentally introduced in 3.11a4.

  • bpo-46289: ASDL declaration of FormattedValue has changed to reflect conversion field is not optional.

  • bpo-46297: Fixed an interpreter crash on bootup with multiple PythonPaths set in the Windows registry. Patch by Derzsi Dániel.

  • bpo-46237: Fix the line number of tokenizer errors inside f-strings. Patch by Pablo Galindo.

  • bpo-46263: We always expect the «use_frozen_modules» config to be set, now that getpath.c was rewritten in pure Python and the logic improved.

  • bpo-46006: Fix a regression when a type method like __init__() is modified in a subinterpreter. Fix a regression in _PyUnicode_EqualToASCIIId() and type update_slot(). Revert the change which made the Unicode dictionary of interned strings compatible with subinterpreters: the internal interned dictionary is shared again by all interpreters. Patch by Victor Stinner.

  • bpo-45923: Add RESUME opcode. This is a logical no-op. It is emitted by the compiler anywhere a Python function can be entered. It is used by the interpreter to perform tracing and optimizer checks.

  • bpo-46208: Fix the regression of os.path.normpath(«A/../../B») not returning expected «../B» but «B».

  • bpo-46240: Correct the error message for unclosed parentheses when the tokenizer doesn’t reach the end of the source when the error is reported. Patch by Pablo Galindo

  • bpo-46009: Remove the GEN_START opcode.

  • bpo-46235: Certain sequence multiplication operations like [0] * 1_000 are now faster due to reference-counting optimizations. Patch by Dennis Sweeney.

  • bpo-46221: PREP_RERAISE_STAR no longer pushes lasti to the stack.

  • bpo-46202: Remove POP_EXCEPT_AND_RERAISE and replace it by an equivalent sequence of other opcodes.

  • bpo-46085: Fix iterator cache mechanism of OrderedDict.

  • bpo-46055: Speed up shifting operation involving integers less than PyLong_BASE. Patch by Xinhang Xu.

  • bpo-46110: Add a maximum recursion check to the PEG parser to avoid stack overflow. Patch by Pablo Galindo

  • bpo-46107: Fix bug where ExceptionGroup.split() and ExceptionGroup.subgroup() did not copy the exception group’s __note__ field to the parts.

  • bpo-45711: The interpreter state’s representation of handled exceptions (a.k.a exc_info, or _PyErr_StackItem) now has only the exc_value field, exc_type and exc_traceback have been removed as their values can be derived from exc_value.

  • bpo-44525: Replace the four call bytecode instructions which one pre-call instruction and two call instructions.


    Adds CALL_NO_KW and CALL_KW call instructions, and PRECALL_METHOD prefix for pairing with LOAD_METHOD.

  • bpo-46039: Remove the YIELD_FROM instruction and replace it with the SEND instruction which performs the same operation, but without the loop.

  • bpo-45635: The code called from _PyErr_Display() was refactored to improve error handling. It now exits immediately upon an unrecoverable error.

  • bpo-46054: Fix parser error when parsing non-utf8 characters in source files. Patch by Pablo Galindo.

  • bpo-46042: Improve the location of the caret in SyntaxError exceptions emitted by the symbol table. Patch by Pablo Galindo.

  • bpo-46049: Ensure ._pth files work as intended on platforms other than Windows.

  • bpo-46048: Fixes parsing of ._pth files on startup so that single-character paths are correctly read.

  • bpo-37971: Fix a bug where the line numbers given in a traceback when a decorator application raised an exception were wrong.

  • bpo-46031: Add POP_JUMP_IF_NOT_NONE and POP_JUMP_IF_NONE opcodes to speed up conditional jumps.

  • bpo-45654: Deepfreeze runpy, patch by Kumar Aditya.

  • bpo-46025: Fix a crash in the atexit module involving functions that unregister themselves before raising exceptions. Patch by Pablo Galindo.

  • bpo-46000: Improve compatibility of the curses module with NetBSD curses.

  • bpo-44525: Specialize the CALL_FUNCTION instruction for calls to builtin types with a single argument. Speeds up range(x), list(x), and specifically type(obj).

  • bpo-42918: Fix bug where the built-in compile() function did not always raise a SyntaxError when passed multiple statements in “single” mode. Patch by Weipeng Hong.

  • bpo-45953: The main interpreter in _PyRuntimeState.interpreters is now statically allocated (as part of _PyRuntime). Likewise for the initial thread state of each interpreter. This means less allocation during runtime init, as well as better memory locality for these key state objects.

  • bpo-45292: Complete the PEP 654 implementation: add except*.

  • bpo-43413: Revert changes in set.__init__. Subclass of set needs to define a __init__() method if it defines a __new__() method with additional keyword parameters.

  • bpo-43931: Added the Py_Version constant which bears the same value as PY_VERSION_HEX. Patch by Gabriele N. Tornetta.


  • bpo-46342: The decorator now sets the __final__ attribute on the decorated object to allow runtime introspection. Patch by Jelle Zijlstra.

  • bpo-46328: Added the sys.exception() method which returns the active exception instance.

  • bpo-46307: Add string.Template.is_valid() and string.Template.get_identifiers() methods.

  • bpo-46306: Assume that types.CodeType always has types.CodeType.co_firstlineno in doctest.

  • bpo-40479: Fix hashlib usedforsecurity option to work correctly with OpenSSL 3.0.0 in FIPS mode.

  • bpo-46070: Fix possible segfault when importing the asyncio module from different sub-interpreters in parallel. Patch by Erlend E. Aasland.

  • bpo-46244: Removed __slots__ from typing.ParamSpec and typing.TypeVar. They served no purpose. Patch by Arie Bovenberg.

  • bpo-46278: Reflect context argument in AbstractEventLoop.call_*() methods. Loop implementations already support it.

  • bpo-46269: Remove special-casing of __new__ in enum.Enum.__dir__().

  • bpo-46266: Improve day constants in calendar.

    Now all constants (MONDAYSUNDAY) are documented, tested, and added to __all__.

  • bpo-46257: Optimized the mean, variance, and stdev functions in the statistics module. If the input is an iterator, it is consumed in a single pass rather than eating memory by conversion to a list. The single pass algorithm is about twice as fast as the previous two pass code.

  • bpo-41011: Added two new variables to pyvenv.cfg which is generated by venv module: executable for the executable and command for the command line used to create the environment.

  • bpo-46239: Improve error message when importing asyncio.windows_events on non-Windows.

  • bpo-46238: Reuse _winapi constants in asyncio.windows_events.

  • bpo-46222: Adding SF_NOCACHE sendfile constant for FreeBSD for the posixmodule.

  • bpo-37295: Add fast path for 0 <= k <= n <= 67 for math.comb().

  • bpo-46176: Adding the MAP_STACK constant for the mmap module.

  • bpo-43424: Deprecate webbrowser.MacOSXOSAScript._name and use name instead.

  • bpo-45321: Added missing error codes to module xml.parsers.expat.errors.

  • bpo-46125: Refactor tests to test traversable API directly. Includes changes from importlib 5.4.0.

  • bpo-46118: Moved importlib.resources and its related functionality to a package.

  • bpo-37578: Add include_hidden parameter to glob() and iglob() to match hidden files and directories when using special characters like *, **, ? and [].

  • bpo-20369: concurrent.futures.wait() no longer blocks forever when given duplicate Futures. Patch by Kumar Aditya.

  • bpo-46105: Honor spec when generating requirement specs with urls and extras (importlib_metadata 4.8.3).

  • bpo-44893: EntryPoint objects are no longer tuples. Recommended means to access is by attribute (“.name”, “.group”) or accessor (“.load()”). Access by index is deprecated and will raise deprecation warning.

  • bpo-22815: Print unexpected successes together with failures and errors in summary in unittest.TextTestResult.

  • bpo-22047: Calling add_argument_group() on an argument group is deprecated. Calling add_argument_group() or add_mutually_exclusive_group() on a mutually exclusive group is deprecated.

    These features were never supported and do not always work correctly. The functions exist on the API by accident through inheritance and will be removed in the future.

  • bpo-26952: argparse raises ValueError with clear message when trying to render usage for an empty mutually exclusive group. Previously it raised a cryptic IndexError.

  • bpo-45615: Functions in the traceback module raise TypeError rather than AttributeError when an exception argument is not of type BaseException.

  • bpo-16594: Add allow allow_reuse_port flag in socketserver.

  • bpo-27718: Fix help for the signal module. Some functions (e.g. signal() and getsignal()) were omitted.

  • bpo-46032: The registry() method of functools.singledispatch() functions checks now the first argument or the first parameter annotation and raises a TypeError if it is not supported. Previously unsupported «types» were ignored (e.g. typing.List[int]) or caused an error at calling time (e.g. list[int]).

  • bpo-46014: Add ability to use typing.Union and types.UnionType as dispatch argument to functools.singledispatch. Patch provided by Yurii Karabas.

  • bpo-27062: Add __all__ to inspect, patch by Kumar Aditya.

  • bpo-46018: Ensure that math.expm1() does not raise on underflow.

  • bpo-46016: Adding F_DUP2FD and F_DUP2FD_CLOEXEC constants from FreeBSD into the fcntl module.

  • bpo-45755: typing generic aliases now reveal the class attributes of the original generic class when passed to dir(). This was the behavior up to Python 3.6, but was changed in 3.7-3.9.

  • bpo-45874: The empty query string, consisting of no query arguments, is now handled correctly in urllib.parse.parse_qsl. This caused problems before when strict parsing was enabled.

  • bpo-44674: Change how dataclasses disallows mutable default values. It used to use a list of known types (list, dict, set). Now it disallows unhashable objects to be defaults. It’s using unhashability as a proxy for mutability. Patch by Eric V. Smith, idea by Raymond Hettinger.

  • bpo-23882: Remove namespace package (PEP 420) support from unittest discovery. It was introduced in Python 3.4 but has been broken since Python 3.7.

  • bpo-25066: Added a __repr__() method to multiprocessing.Event objects, patch by Kumar Aditya.

  • bpo-45643: Added signal.SIGSTKFLT on platforms where this signal is defined.

  • bpo-44092: Fetch across rollback no longer raises InterfaceError. Instead we leave it to the SQLite library to handle these cases. Patch by Erlend E. Aasland.

  • bpo-42413: Replace concurrent.futures.TimeoutError and asyncio.TimeoutError with builtin TimeoutError, keep these names as deprecated aliases.



  • bpo-46296: Add a test case for enum with _use_args_ == True and _member_type_ == object.

  • bpo-46205: Fix hang in runtest_mp due to race condition

  • bpo-46263: Fix test_capi on FreeBSD 14-dev: instruct jemalloc to not fill freed memory with junk byte.

  • bpo-46262: Cover ValueError path in tests for enum.Flag._missing_().

  • bpo-46150: Now fakename in test_pathlib.PosixPathTest.test_expanduser is checked to be non-existent.

  • bpo-46129: Rewrite asyncio.locks tests with unittest.IsolatedAsyncioTestCase usage.

  • bpo-23819: Fixed asyncio tests in python optimized mode. Patch by Kumar Aditya.

  • bpo-46114: Fix test case for OpenSSL 3.0.1 version. OpenSSL 3.0 uses 0xMNN00PP0L.


  • bpo-44133: When Python is configured with --without-static-libpython, the Python static library (libpython.a) is no longer built. Patch by Victor Stinner.

  • bpo-44133: When Python is built without --enable-shared, the python program is now linked to object files, rather than being linked to the Python static library (libpython.a), to make sure that all symbols are exported. Previously, the linker omitted some symbols like the Py_FrozenMain() function. Patch by Victor Stinner.

  • bpo-40280: The configure script has a new option --with-emscripten-target to select browser or node as Emscripten build target.

  • bpo-46315: Added and fixed #ifdef HAVE_FEATURE checks for functionality that is not available on WASI platform.

  • bpo-45723: Fixed a regression in configure check for select.epoll().

  • bpo-46263: configure no longer sets MULTIARCH on FreeBSD platforms.

  • bpo-46106: Updated OpenSSL to 1.1.1m in Windows builds, macOS installer builds, and CI. Patch by Kumar Aditya.

  • bpo-46088: Automatically detect or install bootstrap Python runtime when building from Visual Studio.

  • bpo-46072: Add a –with-pystats configure option to turn on internal statistics gathering.

  • bpo-40280: A new directory Tools/wasm contains WebAssembly-related helpers like override for wasm32-emscripten, wasm assets generator to bundle the stdlib, and a README.

  • bpo-46023: makesetup no longer builds extensions that have been marked as disabled. This allows users to disable modules in Modules/Setup.local.

  • bpo-45949: Use pure Python freeze_module for all but importlib bootstrap files. --with-freeze-module configure option is no longer needed for cross builds.


  • bpo-46217: Removed parameter that is unsupported on Windows 8.1 and early Windows 10 and may have caused build or runtime failures.


  • bpo-40477: The Python Launcher app for macOS now properly launches scripts and, if necessary, the Terminal app when running on recent macOS releases.


Python 3.11.0 alpha 3

Release date: 2021-12-08

Core and Builtins

  • bpo-46009: Restore behavior from 3.9 and earlier when sending non-None to newly started generator. In 3.9 this did not affect the state of the generator. In 3.10.0 and 3.10.1 gen_func().send(0) is equivalent to gen_func().throw(TypeError(...) which exhausts the generator. In 3.10.2 onward, the behavior has been reverted to that of 3.9.

  • bpo-46004: Fix the SyntaxError location for errors involving for loops with invalid targets. Patch by Pablo Galindo

  • bpo-45711: _PyErr_ChainStackItem() no longer normalizes exc_info (including setting the traceback on the exception instance) because exc_info is always normalized.

  • bpo-45607: The __note__ field was added to BaseException. It is None by default but can be set to a string which is added to the exception’s traceback.

  • bpo-45947: Place pointers to dict and values immediately before GC header. This reduces number of dependent memory loads to access either dict or values from 3 to 1.

  • bpo-45915: is_valid_fd now uses faster fcntl(fd, F_GETFD) on Linux, macOS, and Windows.

  • bpo-44530: Reverts a change to the code.__new__ audit event from an earlier prerelease.

  • bpo-42268: Fail the configure step if the selected compiler doesn’t support memory sanitizer. Patch by Pablo Galindo

  • bpo-45711: The three values of exc_info are now always consistent with each other. In particular, the type and traceback fields are now derived from the exception instance. This impacts the return values of sys.exc_info() and PyErr_GetExcInfo() if the exception instance is modified while the exception is handled, as well as PyErr_SetExcInfo(), which now ignores the type and traceback arguments provided to it.

  • bpo-45727: Refine the custom syntax error that suggests that a comma may be missing to trigger only when the expressions are detected between parentheses or brackets. Patch by Pablo Galindo

  • bpo-45885: Specialized the COMPARE_OP opcode using the PEP 659 machinery.

  • bpo-45786: Allocate space for the interpreter frame in the frame object, to avoid an additional allocation when the frame object outlives the frame activation.

  • bpo-45614: Fix traceback display for exceptions with invalid module name.

  • bpo-45813: Fix crash when calling coro.cr_frame.clear() after coroutine has been freed.

  • bpo-45811: Improve the tokenizer errors when encountering invisible control characters in the parser. Patch by Pablo Galindo

  • bpo-45848: Allow the parser to obtain error lines directly from encoded files. Patch by Pablo Galindo

  • bpo-45709: Restore behavior from 3.10 when tracing an exception raised within a with statement.

  • bpo-44525: Adds new COPY_FREE_VARS opcode, to make copying of free variables from function to frame explicit. Helps optimization of calls to Python function.

  • bpo-45829: Specialize BINARY_SUBSCR for classes with a __getitem__ method implemented in Python

  • bpo-45826: Fixed a crash when calling .with_traceback(None) on NameError. This occurs internally in unittest.TestCase.assertRaises().

  • bpo-45822: Fixed a bug in the parser that was causing it to not respect PEP 263 coding cookies when no flags are provided. Patch by Pablo Galindo

  • bpo-45820: Fix a segfault when the parser fails without reading any input. Patch by Pablo Galindo

  • bpo-45636: Simplify the implementation of BINARY_OP by indexing into an array of function pointers (rather than switching on the oparg).

  • bpo-42540: Fix crash when os.fork() is called with an active non-default memory allocator.

  • bpo-45738: Fix computation of error location for invalid continuation characters in the parser. Patch by Pablo Galindo.

  • bpo-45636: Remove an existing «fast path» for old-style string formatting, since it no longer appears to have any measurable impact.

  • bpo-45753: Make recursion checks a bit more efficient by tracking amount of calls left before overflow.

  • bpo-45773: Fix a compiler hang when attempting to optimize certain jump patterns.

  • bpo-45764: The parser now gives a better error message when leaving out the opening parenthesis ( after a def-statement:

    >>> def f:
      File "<stdin>", line 1
        def f:
    SyntaxError: expected '('
  • bpo-45609: Specialized the STORE_SUBSCR opcode using the PEP 659 machinery.

  • bpo-45636: Replace all numeric BINARY_* and INPLACE_* instructions with a single BINARY_OP implementation.

  • bpo-45582: Path calculation (known as getpath) has been reimplemented as a frozen Python module. This should have no visible impact, but may affect calculation of all paths referenced in sys and sysconfig.

  • bpo-45450: Improve the syntax error message for parenthesized arguments. Patch by Pablo Galindo.


  • bpo-27946: Fix possible crash when getting an attribute of class:xml.etree.ElementTree.Element simultaneously with replacing the attrib dict.

  • bpo-45711: Make asyncio normalize exceptions as soon as they are captured with PyErr_Fetch(), and before they are stored as an exc_info triplet. This brings asyncio in line with the rest of the codebase, where an exc_info triplet is always normalized.

  • bpo-23819: Replaced asserts with exceptions in asyncio, patch by Kumar Aditya.

  • bpo-13236: unittest.TextTestResult and unittest.TextTestRunner flush now the output stream more often.

  • bpo-45917: Added math.exp2():, which returns 2 raised to the power of x.

  • bpo-37658: Fix issue when on certain conditions asyncio.wait_for() may allow a coroutine to complete successfully, but fail to return the result, potentially causing memory leaks or other issues.

  • bpo-45876: Improve the accuracy of stdev() and pstdev() in the statistics module. When the inputs are floats or fractions, the output is a correctly rounded float

  • bpo-44649: Handle dataclass(slots=True) with a field that has default a default value, but for which init=False.

  • bpo-45803: Added missing kw_only parameter to dataclasses.make_dataclass().

  • bpo-45837: The turtle.RawTurtle.settiltangle() is deprecated since Python 3.1, it now emits a deprecation warning and will be removed in Python 3.13.

    Use turtle.RawTurtle.tiltangle() instead.

    turtle.RawTurtle.tiltangle() was earlier incorrectly marked as deprecated, its docstring has been corrected.

    Patch by Hugo van Kemenade.

  • bpo-45831: faulthandler can now write ASCII-only strings (like filenames and function names) with a single write() syscall when dumping a traceback. It reduces the risk of getting an unreadable dump when two threads or two processes dump a traceback to the same file (like stderr) at the same time. Patch by Victor Stinner.

  • bpo-45828: sqlite C callbacks now use unraisable exceptions if callback tracebacks are enabled. Patch by Erlend E. Aasland.

  • bpo-41735: Fix thread lock in zlib.Decompress.flush() method before PyObject_GetBuffer.

  • bpo-45235: Reverted an argparse bugfix that caused regression in the handling of default arguments for subparsers. This prevented leaf level arguments from taking precedence over root level arguments.

  • bpo-45754: Fix a regression in Python 3.11a1 and 3.11a2 where sqlite3 incorrectly would use SQLITE_LIMIT_LENGTH when checking SQL statement lengths. Now, SQLITE_LIMIT_SQL_LENGTH is used. Patch by Erlend E. Aasland.

  • bpo-45766: Added proportional option to statistics.linear_regression().

  • bpo-45765: In importlib.metadata, fix distribution discovery for an empty path.

  • bpo-45757: Fix bug where dis produced an incorrect oparg when EXTENDED_ARG is followed by an opcode that does not use its argument.

  • bpo-45644: In-place JSON file formatting using python3 -m json.tool infile infile now works correctly, previously it left the file empty. Patch by Chris Wesseling.

  • bpo-45703: When a namespace package is imported before another module from the same namespace is created/installed in a different sys.path location while the program is running, calling the importlib.invalidate_caches() function will now also guarantee the new module is noticed.

  • bpo-45535: Improve output of dir() with Enums.

  • bpo-45664: Fix types.resolve_bases() and types.new_class() for types.GenericAlias instance as a base.

  • bpo-45663: Fix dataclasses.is_dataclass() for dataclasses which are subclasses of types.GenericAlias.

  • bpo-45662: Fix the repr of dataclasses.InitVar with a type alias to the built-in class, e.g. InitVar[list[int]].

  • bpo-43137: Launch GNOME web browsers via gio tool instead of obsolete gvfs-open

  • bpo-45429: On Windows, time.sleep() now uses a waitable timer which supports high-resolution timers. Patch by Dong-hee Na and Eryk Sun.

  • bpo-37295: Optimize math.comb() and math.perm().

  • bpo-45514: Deprecated legacy functions in importlib.resources.

  • bpo-45507: Add tests for truncated/missing trailers in gzip.decompress implementation.

  • bpo-45359: Implement PEP 585 for graphlib.TopologicalSorter.

  • bpo-44733: Add max_tasks_per_child to concurrent.futures.ProcessPoolExecutor. This allows users to specify the maximum number of tasks a single process should execute before the process needs to be restarted.

  • bpo-28806: Improve netrc library. netrc file no longer needs to contain all tokens. And if the login name is anonymous, security check is no longer need.

  • bpo-43498: Avoid a possible «RuntimeError: dictionary changed size during iteration» when adjusting the process count of ProcessPoolExecutor.

  • bpo-42158: Add MIME types for N-quads, N-triples, Notation3 and TriG to mimetypes.

  • bpo-30533: Add inspect.getmembers_static() , it return all members without triggering dynamic lookup via the descriptor protocol. Patch by Weipeng Hong.


  • bpo-42238: make -C Doc suspicious will be removed soon in favor of make -C Doc check, mark it as deprecated.

  • bpo-45840: Improve cross-references in the documentation for the data model.

  • bpo-45640: Properly marked-up grammar tokens in the documentation are now clickable and take you to the definition of a given piece of grammar. Patch by Arthur Milchior.

  • bpo-45788: Link doc for sys.prefix to sysconfig doc on installation paths.

  • bpo-45772: socket.socket documentation is corrected to a class from a function.

  • bpo-45392: Update the docstring of the type built-in to remove a redundant line and to mention keyword arguments for the constructor.

  • bpo-45250: Update the documentation to note that CPython does not consistently require iterators to define __iter__.

  • bpo-25381: In the extending chapter of the extending doc, update a paragraph about the global variables containing exception information.

  • bpo-43905: Expanded astuple() and asdict() docs, warning about deepcopy being applied and providing a workaround.


  • bpo-45695: Out-of-tree builds with a read-only source directory are now tested by CI.

  • bpo-19460: Add new Test for Lib/email/mime/

  • bpo-45835: Fix race condition in test_queue tests with multiple «feeder» threads.

  • bpo-45783: The test for the freeze tool now handles file moves and deletions.

  • bpo-45745: Remove the --findleaks command line option of regrtest: use the --fail-env-changed option instead. Since Python 3.7, it was a deprecated alias to the --fail-env-changed option.

  • bpo-45701: Add tests with tuple type with functools.lru_cache() to test_functools.


  • bpo-44035: CI now verifies that autoconf files have been regenerated with a current and unpatched autoconf package.

  • bpo-45950: The build system now uses a _bootstrap_python interpreter for freezing and deepfreezing again. To speed up build process the build tools _bootstrap_python and _freeze_module are no longer build with LTO.

  • bpo-45881: The configure script now accepts --with-build-python and --with-freeze-module options to make cross compiling easier.

  • bpo-40280: Emscripten platform now uses .wasm suffix by default.

  • bpo-40280: Disable unusable core extension modules on WASM/Emscripten targets.

  • bpo-40280: configure now checks for socket shutdown function. The check makes it possible to disable SYS_shutdown with ac_cv_func_shutdown=no in CONFIG_SITE.

  • bpo-40280: configure now checks for functions fork1, getegid, geteuid, getgid, getppid, getuid, opendir, pipe, system, wait, ttyname.

  • bpo-33393: Update config.guess to 2021-06-03 and config.sub to 2021-08-14. Makefile now has an update-config target to make updating more convenient.

  • bpo-45866: make regen-all now produces the same output when run from a directory other than the source tree: when building Python out of the source tree. pegen now strips directory of the «generated by pygen from <FILENAME>» header Patch by Victor Stinner.

  • bpo-40280: configure now accepts machine wasm32 or wasm64 and OS wasi or emscripten for cross building, e.g. wasm32-unknown-emscripten, wasm32-wasi, or wasm32-unknown-wasi.

  • bpo-41498: Python now compiles on platforms without sigset_t. Several functions in signal are not available when sigset_t is missing.

    Based on patch by Roman Yurchak for pyodide.

  • bpo-45881: now uses CC from environment first to discover multiarch and cross compile paths.

  • bpo-45886: The _freeze_module program path can now be overridden on the command line, e.g. make FREEZE_MODULE=../x86_64/Program/_freeze_module.

  • bpo-45873: Get rid of the _bootstrap_python build step. The script is now run using $(PYTHON_FOR_REGEN) which can be Python 3.7 or newer (on Windows, 3.8 or newer).

  • bpo-45847: Port builtin hashlib extensions to PY_STDLIB_MOD macro and addext().

  • bpo-45723: Add autoconf helpers for saving and restoring environment variables:




    Patch by Erlend E. Aasland.

  • bpo-45573: Mandatory core modules, that are required to bootstrap Python, are now in Modules/Setup.bootstrap.

  • bpo-45573: configure now creates Modules/Setup.stdlib with conditionally enabled/disabled extension module lines. The file is not used, yet.

  • bpo-45573: configure now uses a unified format to set state, compiler flags, and linker flags in Makefile. The new macro PY_STDLIB_MOD sets three variables that are consumed by Modules/Setup and

  • bpo-45816: Python now supports building with Visual Studio 2022 (MSVC v143, VS Version 17.0). Patch by Jeremiah Vivian.

  • bpo-45800: Settings for pyexpat C extension are now detected by configure. The bundled expat library is built in Makefile.

  • bpo-45798: Settings for decimal internal C extension are now detected by configure. The bundled libmpdec library is built in Makefile.

  • bpo-45723: configure has a new option --with-pkg-config to disable or require pkg-config.

  • bpo-45774: The build dependencies for sqlite3 are now detected by configure and pkg-config. Patch by Erlend E. Aasland.

  • bpo-45763: The build dependencies for zlib, bz2, and lzma are now detected by configure.

  • bpo-45747: gdbm and dbm build dependencies are now detected by configure.

  • bpo-45743: On macOS, the build system no longer passes search_paths_first to the linker. The flag has been the default since Xcode 4 / macOS 10.6.

  • bpo-45723: is now compatible with autoconf 2.71. Deprecated checks STDC_HEADERS and AC_HEADER_TIME have been removed.

  • bpo-45723: configure now prints a warning when pkg-config is missing.

  • bpo-45731: configure --enable-loadable-sqlite-extensions is now handled by new PY_SQLITE_ENABLE_LOAD_EXTENSION macro instead of logic in

  • bpo-45723: now uses custom helper macros and AC_CACHE_CHECK to simplify and speed up configure runs.

  • bpo-45696: Skip the marshal step for frozen modules by generating C code that produces a set of ready-to-use code objects. This speeds up startup time by another 10% or more.

  • bpo-45561: Run tool from $(srcdir).


  • bpo-46105: Fixed calculation of sys.path in a venv on Windows.

  • bpo-45901: When installed through the Microsoft Store and set as the default app for *.py files, command line arguments will now be passed to Python when invoking a script without explicitly launching Python (that is, args rather than python args).

  • bpo-45616: Fix Python Launcher’s ability to distinguish between versions 3.1 and 3.10 when either one is explicitly requested. Previously, 3.1 would be used if 3.10 was requested but not installed, and 3.10 would be used if 3.1 was requested but 3.10 was installed.

  • bpo-45850: Implement changes to build with deep-frozen modules on Windows. Note that we now require Python 3.10 as the «bootstrap» or «host» Python.

  • bpo-45732: Updates bundled Tcl/Tk to 8.6.12.

  • bpo-45720: Internal reference to shlwapi.dll was dropped to help improve startup time. This DLL will no longer be loaded at the start of every Python process.


  • bpo-45732: Update macOS installer to use Tcl/Tk 8.6.12.


  • bpo-39026: Fix Python.h to build C extensions with Xcode: remove a relative include from Include/cpython/pystate.h.

Python 3.11.0 alpha 2

Release date: 2021-11-05

Core and Builtins

  • bpo-45716: Improve the SyntaxError message when using True, None or False as keywords in a function call. Patch by Pablo Galindo.

  • bpo-45688: sys.stdlib_module_names now contains the macOS-specific module _scproxy.

  • bpo-45379: Clarify ImportError message when we try to explicitly import a frozen module but frozen modules are disabled.

  • bpo-44525: Specialize simple calls to Python functions (no starargs, keyowrd dict, or closure)

  • bpo-45530: Cases of sorting using tuples as keys may now be significantly faster in some cases. Patch by Tim Peters.

    The order of the result may differ from earlier releases if the tuple elements don’t define a total ordering (see Comparaciones de valor for information on total ordering). It’s generally true that the result of sorting simply isn’t well-defined in the absence of a total ordering on list elements.

  • bpo-45526: In obmalloc, set ADDRESS_BITS to not ignore any bits (ignored 16 before). That is safer in the case that the kernel gives user-space virtual addresses that span a range greater than 48 bits.

  • bpo-30570: Fixed a crash in issubclass() from infinite recursion when searching pathological __bases__ tuples.

  • bpo-45521: Fix a bug in the obmalloc radix tree code. On 64-bit machines, the bug causes the tree to hold 46-bits of virtual addresses, rather than the intended 48-bits.

  • bpo-45494: Fix parser crash when reporting errors involving invalid continuation characters. Patch by Pablo Galindo.

  • bpo-45445: Python now fails to initialize if it finds an invalid -X option in the command line. Patch by Pablo Galindo.

  • bpo-45340: Object attributes are held in an array instead of a dictionary. An object’s dictionary are created lazily, only when needed. Reduces the memory consumption of a typical Python object by about 30%. Patch by Mark Shannon.

  • bpo-45408: Fix a crash in the parser when reporting tokenizer errors that occur at the same time unclosed parentheses are detected. Patch by Pablo Galindo.

  • bpo-29410: Add SipHash13 for string hash algorithm and use it by default.

  • bpo-45385: Fix reference leak from descr_check. Patch by Dong-hee Na.

  • bpo-45367: Specialized the BINARY_MULTIPLY opcode to BINARY_MULTIPLY_INT and BINARY_MULTIPLY_FLOAT using the PEP 659 machinery.

  • bpo-21736: Frozen stdlib modules now have __file__ to the .py file they would otherwise be loaded from, if possible. For packages, __path__ now has the correct entry instead of being an empty list, which allows unfrozen submodules to be imported. These are set only if the stdlib directory is known when the runtime is initialized. Note that the file at __file__ is not guaranteed to exist. None of this affects non-stdlib frozen modules nor, for now, frozen modules imported using PyImport_ImportFrozenModule(). Also, at the moment co_filename is not updated for the module.

  • bpo-45020: For frozen stdlib modules, record the original module name as module.__spec__.loader_state.origname. If the value is different than then the module was defined as an alias in Tools/scripts/ If it is None then the module comes from a source file outside the stdlib.

  • bpo-45324: In FrozenImporter.find_spec(), we now preserve the information needed in exec_module() to load the module. This change mostly impacts internal details, rather than changing the importer’s behavior.

  • bpo-45292: Implement PEP 654. Add ExceptionGroup and BaseExceptionGroup. Update traceback display code.

  • bpo-40116: Change to the implementation of split dictionaries. Classes where the instances differ either in the exact set of attributes, or in the order in which those attributes are set, can still share keys. This should have no observable effect on users of Python or the C-API. Patch by Mark Shannon.

  • bpo-44050: Extensions that indicate they use global state (by setting m_size to -1) can again be used in multiple interpreters. This reverts to behavior of Python 3.8.

  • bpo-44525: Setup initial specialization infrastructure for the CALL_FUNCTION opcode. Implemented initial specializations for C function calls:


    • CALL_FUNCTION_BUILTIN_FAST for METH_FASTCALL flag without keywords.

    • CALL_FUNCTION_LEN for len(o).

    • CALL_FUNCTION_ISINSTANCE for isinstance(o, t).

  • bpo-44511: Improve the generated bytecode for class and mapping patterns.

  • bpo-43706: Speed up calls to enumerate() by using the PEP 590 vectorcall calling convention. Patch by Dong-hee Na.


  • bpo-45679: Fix caching of multi-value typing.Literal. Literal[True, 2] is no longer equal to Literal[1, 2].

  • bpo-42064: Convert sqlite3 to multi-phase initialisation (PEP 489). Patches by Erlend E. Aasland.

  • bpo-45438: Fix typing.Signature string representation for generic builtin types.

  • bpo-45613: sqlite3 now sets sqlite3.threadsafety based on the default threading mode the underlying SQLite library has been compiled with. Patch by Erlend E. Aasland.

  • bpo-45574: Fix warning about print_escape being unused.

  • bpo-45581: sqlite3.connect() now correctly raises MemoryError if the underlying SQLite API signals memory error. Patch by Erlend E. Aasland.

  • bpo-45557: pprint.pprint() now handles underscore_numbers correctly. Previously it was always setting it to False.

  • bpo-44019: Add to operator.__all__. Patch by Kreusada.

  • bpo-42174: shutil.get_terminal_size() now falls back to sane values if the column or line count are 0.

  • bpo-35673: Improve the introspectability of the __loader__ attribute for namespace packages. importlib.machinery.NamespaceLoader is now public, and implements the interface. _NamespaceLoader is kept for backward compatibility.

  • bpo-45515: Add references to zoneinfo in the datetime documentation, mostly replacing outdated references to Change by Paul Ganssle.

  • bpo-45475: Reverted optimization of iterating gzip.GzipFile, bz2.BZ2File, and lzma.LZMAFile (see bpo-43787) because it caused regression when user iterate them without having reference of them. Patch by Inada Naoki.

  • bpo-45489: Update ForwardRef to support | operator. Patch by Dong-hee Na.

  • bpo-42222: Removed deprecated support for float arguments in randrange().

  • bpo-45428: Fix a regression in py_compile when reading filenames from standard input.

  • bpo-45467: Fix incremental decoder and stream reader in the «raw-unicode-escape» codec. Previously they failed if the escape sequence was split.

  • bpo-45461: Fix incremental decoder and stream reader in the «unicode-escape» codec. Previously they failed if the escape sequence was split.

  • bpo-45239: Fixed email.utils.parsedate_tz() crashing with UnboundLocalError on certain invalid input instead of returning None. Patch by Ben Hoyt.

  • bpo-45417: Fix quadratic behaviour in the enum module: Creation of enum classes with a lot of entries was quadratic.

  • bpo-45249: Fix the behaviour of traceback.print_exc() when displaying the caret when the end_offset in the exception is set to 0. Patch by Pablo Galindo

  • bpo-45416: Fix use of asyncio.Condition with explicit asyncio.Lock objects, which was a regression due to removal of explicit loop arguments. Patch by Joongi Kim.

  • bpo-20028: Empty escapechar/quotechar is not allowed when initializing csv.Dialect. Patch by Vajrasky Kok and Dong-hee Na.

  • bpo-44904: Fix bug in the doctest module that caused it to fail if a docstring included an example with a classmethod property. Patch by Alex Waygood.

  • bpo-45406: Make inspect.getmodule() catch FileNotFoundError raised by :”func:inspect.getabsfile, and return None to indicate that the module could not be determined.

  • bpo-45411: Add extensions for files containing subtitles - .srt & .vtt - to the module.

  • bpo-10716: Migrated pydoc to HTML5 (without changing the look of it). Side effect is to update xmlrpc’s ServerHTMLDoc which now uses the CSS too. cgitb now relies less on pydoc (as it can’t use the CSS file).

  • bpo-27580: Add support of null characters in csv.

  • bpo-45262: Prevent use-after-free in asyncio. Make sure the cached running loop holder gets cleared on dealloc to prevent use-after-free in get_running_loop

  • bpo-45386: Make xmlrpc.client more robust to C runtimes where the underlying C strftime function results in a ValueError when testing for year formatting options.

  • bpo-20028: Improve error message of csv.Dialect when initializing. Patch by Vajrasky Kok and Dong-hee Na.

  • bpo-45343: Update bundled pip to 21.2.4 and setuptools to 58.1.0

  • bpo-45328: Fixed http.client.HTTPConnection to work properly in OSs that don’t support the TCP_NODELAY socket option.

  • bpo-45243: Add setlimit() and getlimit() to sqlite3.Connection for setting and getting SQLite limits by connection basis. Patch by Erlend E. Aasland.

  • bpo-45320: Removed from the inspect module:

    Patch by Hugo van Kemenade.

  • bpo-45192: Fix the tempfile._infer_return_type function so that the dir argument of the tempfile functions accepts an object implementing the os.PathLike protocol.

    Patch by Kyungmin Lee.

  • bpo-45160: When tracing a tkinter variable used by a ttk OptionMenu, callbacks are no longer made twice.

  • bpo-25625: Added non parallel-safe chdir() context manager to change the current working directory and then restore it on exit. Simple wrapper around chdir().

  • bpo-24139: Add support for SQLite extended result codes in sqlite3.Error. Patch by Erlend E. Aasland.

  • bpo-24444: Fixed an error raised in argparse help display when help for an option is set to 1+ blank spaces or when choices arg is an empty container.

  • bpo-44547: Implement Fraction.__int__, so that a fractions.Fraction instance f passes an isinstance(f, typing.SupportsInt) check.

  • bpo-40321: Adds support for HTTP 308 redirects to urllib. See RFC 7538 for details. Patch by Jochem Schulenklopper.

  • bpo-41374: Ensure that socket.TCP_* constants are exposed on Cygwin 3.1.6 and greater.

  • bpo-35970: Add help flag to the base64 module’s command line interface. Patch contributed by Robert Kuska.


  • bpo-45726: Improve documentation for functools.singledispatch() and functools.singledispatchmethod.

  • bpo-45680: Amend the docs on GenericAlias objects to clarify that non-container classes can also implement __class_getitem__. Patch contributed by Alex Waygood.

  • bpo-45618: Update Sphinx version used to build the documentation to 4.2.0. Patch by Maciej Olko.

  • bpo-45655: Add a new «relevant PEPs» section to the top of the documentation for the typing module. Patch by Alex Waygood.

  • bpo-45604: Add level argument to multiprocessing.log_to_stderr function docs.

  • bpo-45516: Add protocol description to the documentation.

  • bpo-45464: Mention in the documentation of Built-in Exceptions that inheriting from multiple exception types in a single subclass is not recommended due to possible memory layout incompatibility.

  • bpo-45449: Add note about PEP 585 in

  • bpo-45516: Add protocol description to the documentation.

  • bpo-20692: Add Programming FAQ entry explaining that int literal attribute access requires either a space after or parentheses around the literal.


  • bpo-45678: Add tests for scenarios in which functools.singledispatchmethod is stacked on top of a method that has already been wrapped by two other decorators. Patch by Alex Waygood.

  • bpo-45578: Add tests for dis.distb()

  • bpo-45678: Add tests to ensure that functools.singledispatchmethod correctly wraps the attributes of the target function.

  • bpo-45668: PGO tests now pass when Python is built without test extension modules.

  • bpo-45577: Add subtests for all pickle protocols in test_zoneinfo.

  • bpo-45566: Fix test_frozen_pickle in test_dataclasses to check all pickle versions.

  • bpo-43592: test.libregrtest now raises the soft resource limit for the maximum number of file descriptors when the default is too low for our test suite as was often the case on macOS.

  • bpo-39679: Add more test cases for @functools.singledispatchmethod when combined with @classmethod or @staticmethod.

  • bpo-45410: When libregrtest spawns a worker process, stderr is now written into stdout to keep messages order. Use a single pipe for stdout and stderr, rather than two pipes. Previously, messages were out of order which made analysis of buildbot logs harder Patch by Victor Stinner.

  • bpo-45402: Fix test_tools.test_sundry() when Python is built out of tree: fix how the tool locates the _freeze_module program. Patch by Victor Stinner.

  • bpo-45403: Fix test_sys.test_stdlib_dir() when Python is built outside the source tree: compare normalized paths. Patch by Victor Stinner.

  • bpo-45400: Fix test_name_error_suggestions_do_not_trigger_for_too_many_locals() of test_exceptions if a directory name contains «a1» (like «Python-3.11.0a1»): use a stricter regular expression. Patch by Victor Stinner.

  • bpo-10572: Rename sqlite3 tests from test_sqlite to test_sqlite3, and relocate them to Lib/test/test_sqlite3. Patch by Erlend E. Aasland.


  • bpo-43158: now uses values from configure script to build the _uuid extension module. Configure now detects util-linux’s libuuid, too.

  • bpo-45666: Fix warning of swprintf and %s usage in _testembed.c

  • bpo-45548: Modules/Setup and Modules/makesetup have been improved. The Setup file now contains working rules for all extensions. Outdated comments have been removed. Rules defined by makesetup track dependencies correctly.

  • bpo-45548: The math and cmath implementation now require a C99 compatible libm and no longer ship with workarounds for missing acosh, asinh, atanh, expm1, and log1p functions.

  • bpo-45595: and makesetup now track build dependencies on all Python header files and module specific header files.

  • bpo-45571: Modules/Setup now use PY_CFLAGS_NODIST instead of PY_CFLAGS to compile shared modules.

  • bpo-45570: pyexpat and _elementtree no longer define obsolete macros HAVE_EXPAT_CONFIG_H and USE_PYEXPAT_CAPI. XML_POOR_ENTROPY is now defined in expat_config.h.

  • bpo-43974: no longer defines Py_BUILD_CORE_MODULE. Instead every module, that uses the internal API, defines the macro.

  • bpo-45548: Fill in missing entries in Modules/Setup.

  • bpo-45532: Update sys.version to use main as fallback information. Patch by Jeong YunWon.

  • bpo-45536: The configure script now checks whether OpenSSL headers and libraries provide required APIs. Most common APIs are verified. The check detects outdated or missing OpenSSL. Failures do not stop configure.

  • bpo-45221: Fixed regression in handling of LDFLAGS and CPPFLAGS options where argparse.parse_known_args() could interpret an option as one of the built-in command line argument, for example -h for help.

  • bpo-45440: Building Python now requires a C99 <math.h> header file providing the following functions: copysign(), hypot(), isfinite(), isinf(), isnan(), round(). Patch by Victor Stinner.

  • bpo-45405: Prevent internal configure error when running configure with recent versions of non-Apple clang. Patch by David Bohman.

  • bpo-45433: Avoid linking libpython with libcrypt.


  • bpo-43652: Update Tcl/Tk to 8.6.11, actually this time. The previous update incorrectly included 8.6.10.

  • bpo-45337: venv now warns when the created environment may need to be accessed at a different path, due to redirections, links or junctions. It also now correctly installs or upgrades components when the alternate path is required.

  • bpo-43851: Build SQLite SQLITE_OMIT_AUTOINIT on Windows. Patch by Erlend E. Aasland.


  • bpo-44828: Avoid tkinter file dialog failure on macOS 12 Monterey when using the Tk 8.6.11 provided by macOS installers. Patch by Marc Culler of the Tk project.


  • bpo-45495: Add context keywords “case” and “match” to completions list.


  • bpo-29103: PyType_FromSpec* now copies the class name from the spec to a buffer owned by the class, so the original can be safely deallocated. Patch by Petr Viktorin.

  • bpo-45522: The internal freelists for frame, float, list, dict, async generators, and context objects can now be disabled.

  • bpo-35134: Exclude PyWeakref_GET_OBJECT() from the limited C API. It never worked since the PyWeakReference structure is opaque in the limited C API.

  • bpo-35081: Move the interpreteridobject.h header file from Include/ to Include/internal/. It only provides private functions. Patch by Victor Stinner.

  • bpo-35134: The non-limited API files cellobject.h, classobject.h, context.h, funcobject.h, genobject.h and longintrepr.h have been moved to the Include/cpython directory. Moreover, the eval.h header file was removed. These files must not be included directly, as they are already included in Python.h: Include Files. If they have been included directly, consider including Python.h instead. Patch by Victor Stinner.

  • bpo-45474: The following items are no longer available when Py_LIMITED_API is defined:

    These are not part of the limited API.

    Patch by Victor Stinner.

  • bpo-45434: Remove the pystrhex.h header file. It only contains private functions. C extensions should only include the main <Python.h> header file. Patch by Victor Stinner.

  • bpo-45440: Remove the Py_FORCE_DOUBLE() macro. It was used by the Py_IS_INFINITY() macro. Patch by Victor Stinner.

  • bpo-45434<