What's New In Python 3.13¶
- Editor:
Thomas Wouters
This article explains the new features in Python 3.13, compared to 3.12.
For full details, see the changelog.
Voir aussi
PEP 719 -- Python 3.13 Release Schedule
Note
Prerelease users should be aware that this document is currently in draft form. It will be updated substantially as Python 3.13 moves towards release, so it's worth checking back even after reading earlier versions.
Summary -- Release Highlights¶
Python 3.13 beta is the pre-release of the next version of the Python programming language, with a mix of changes to the language, the implementation and the standard library. The biggest changes to the implementation include a new interactive interpreter, and experimental support for dropping the Global Interpreter Lock (PEP 703) and a Just-In-Time compiler (PEP 744). The library changes contain removal of deprecated APIs and modules, as well as the usual improvements in user-friendliness and correctness.
Interpreter improvements:
A greatly improved interactive interpreter and improved error messages.
Color support in the new interactive interpreter, as well as in tracebacks and doctest output. This can be disabled through the
PYTHON_COLORS
andNO_COLOR
environment variables.PEP 744: A basic JIT compiler was added. It is currently disabled by default (though we may turn it on later). Performance improvements are modest -- we expect to be improving this over the next few releases.
PEP 667: The
locals()
builtin now has defined semantics when mutating the returned mapping. Python debuggers and similar tools may now more reliably update local variables in optimized scopes even during concurrent code execution.
New typing features:
PEP 696: Type parameters (
typing.TypeVar
,typing.ParamSpec
, andtyping.TypeVarTuple
) now support defaults.PEP 702: Support for marking deprecations in the type system using the new
warnings.deprecated()
decorator.PEP 742:
typing.TypeIs
was added, providing more intuitive type narrowing behavior.PEP 705:
typing.ReadOnly
was added, to mark an item of atyping.TypedDict
as read-only for type checkers.
Free-threading:
PEP 703: CPython 3.13 has experimental support for running with the global interpreter lock disabled when built with
--disable-gil
. See Free-threaded CPython for more details.
Platform support:
PEP 730: Apple's iOS is now an officially supported platform. Official Android support (PEP 738) is in the works as well.
Removed modules:
PEP 594: The remaining 19 "dead batteries" have been removed from the standard library:
aifc
,audioop
,cgi
,cgitb
,chunk
,crypt
,imghdr
,mailcap
,msilib
,nis
,nntplib
,ossaudiodev
,pipes
,sndhdr
,spwd
,sunau
,telnetlib
,uu
andxdrlib
.Also removed were the
tkinter.tix
andlib2to3
modules, and the2to3
program.
Release schedule changes:
PEP 602 ("Annual Release Cycle for Python") has been updated:
Python 3.9 - 3.12 have one and a half years of full support, followed by three and a half years of security fixes.
Python 3.13 and later have two years of full support, followed by three years of security fixes.
New Features¶
A Better Interactive Interpreter¶
On Unix-like systems like Linux or macOS as well as Windows, Python now uses a new interactive shell. When the user starts the REPL from an interactive terminal the interactive shell now supports the following new features:
Colorized prompts.
Multiline editing with history preservation.
Interactive help browsing using F1 with a separate command history.
History browsing using F2 that skips output as well as the >>> and ... prompts.
"Paste mode" with F3 that makes pasting larger blocks of code easier (press F3 again to return to the regular prompt).
The ability to issue REPL-specific commands like help, exit, and quit without the need to use call parentheses after the command name.
If the new interactive shell is not desired, it can be disabled via
the PYTHON_BASIC_REPL
environment variable.
The new shell requires curses
on Unix-like systems.
For more on interactive mode, see Mode interactif.
(Contributed by Pablo Galindo Salgado, Łukasz Langa, and Lysandros Nikolaou in gh-111201 based on code from the PyPy project. Windows support contributed by Dino Viehland and Anthony Shaw.)
Improved Error Messages¶
The interpreter now colorizes error messages when displaying tracebacks by default. This feature can be controlled via the new
PYTHON_COLORS
environment variable as well as the canonicalNO_COLOR
andFORCE_COLOR
environment variables. See also Controlling color. (Contributed by Pablo Galindo Salgado in gh-112730.)
A common mistake is to write a script with the same name as a standard library module. When this results in errors, we now display a more helpful error message:
$ python random.py Traceback (most recent call last): File "/home/random.py", line 1, in <module> import random; print(random.randint(5)) ^^^^^^^^^^^^^ File "/home/random.py", line 1, in <module> import random; print(random.randint(5)) ^^^^^^^^^^^^^^ AttributeError: module 'random' has no attribute 'randint' (consider renaming '/home/random.py' since it has the same name as the standard library module named 'random' and the import system gives it precedence)
Similarly, if a script has the same name as a third-party module it attempts to import, and this results in errors, we also display a more helpful error message:
$ python numpy.py Traceback (most recent call last): File "/home/numpy.py", line 1, in <module> import numpy as np; np.array([1,2,3]) ^^^^^^^^^^^^^^^^^^ File "/home/numpy.py", line 1, in <module> import numpy as np; np.array([1,2,3]) ^^^^^^^^ AttributeError: module 'numpy' has no attribute 'array' (consider renaming '/home/numpy.py' if it has the same name as a third-party module you intended to import)
(Contributed by Shantanu Jain in gh-95754.)
When an incorrect keyword argument is passed to a function, the error message now potentially suggests the correct keyword argument. (Contributed by Pablo Galindo Salgado and Shantanu Jain in gh-107944.)
>>> "better error messages!".split(max_split=1) Traceback (most recent call last): File "<stdin>", line 1, in <module> "better error messages!".split(max_split=1) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^ TypeError: split() got an unexpected keyword argument 'max_split'. Did you mean 'maxsplit'?
Classes have a new
__static_attributes__
attribute, populated by the compiler, with a tuple of names of attributes of this class which are assigned throughself.X
from any function in its body. (Contributed by Irit Katriel in gh-115775.)
Defined mutation semantics for locals()
¶
Historically, the expected result of mutating the return value of locals()
has been left to individual Python implementations to define.
Through PEP 667, Python 3.13 standardises the historical behaviour of CPython for most code execution scopes, but changes optimized scopes (functions, generators, coroutines, comprehensions, and generator expressions) to explicitly return independent snapshots of the currently assigned local variables, including locally referenced nonlocal variables captured in closures.
This change to the semantics of locals()
in optimized scopes also affects the default
behaviour of code execution functions that implicitly target locals()
if no explicit
namespace is provided (such as exec()
and eval()
). In previous versions, whether
or not changes could be accessed by calling locals()
after calling the code execution
function was implementation dependent. In CPython specifically, such code would typically
appear to work as desired, but could sometimes fail in optimized scopes based on other code
(including debuggers and code execution tracing tools) potentially resetting the shared
snapshot in that scope. Now, the code will always run against an independent snapshot of the
local variables in optimized scopes, and hence the changes will never be visible in
subsequent calls to locals()
. To access the changes made in these cases, an explicit
namespace reference must now be passed to the relevant function. Alternatively, it may make
sense to update affected code to use a higher level code execution API that returns the
resulting code execution namespace (e.g. runpy.run_path()
when executing Python
files from disk).
To ensure debuggers and similar tools can reliably update local variables in
scopes affected by this change, FrameType.f_locals
now
returns a write-through proxy to the frame's local and locally referenced
nonlocal variables in these scopes, rather than returning an inconsistently
updated shared dict
instance with undefined runtime semantics.
See PEP 667 for more details, including related C API changes and deprecations. Porting notes are also provided below for the affected Python APIs and C APIs.
(PEP and implementation contributed by Mark Shannon and Tian Gao in gh-74929. Documentation updates provided by Guido van Rossum and Alyssa Coghlan.)
Incremental Garbage Collection¶
The cycle garbage collector is now incremental. This means that maximum pause times are reduced by an order of magnitude or more for larger heaps.
Support For Mobile Platforms¶
iOS is now a PEP 11 supported platform.
arm64-apple-ios
(iPhone and iPad devices released after 2013) andarm64-apple-ios-simulator
(Xcode iOS simulator running on Apple Silicon hardware) are now tier 3 platforms.x86_64-apple-ios-simulator
(Xcode iOS simulator running on older x86_64 hardware) is not a tier 3 supported platform, but will be supported on a best-effort basis.See PEP 730: for more details.
(PEP written and implementation contributed by Russell Keith-Magee in gh-114099.)
Experimental JIT Compiler¶
When CPython is configured using the --enable-experimental-jit
option,
a just-in-time compiler is added which may speed up some Python programs.
The internal architecture is roughly as follows.
We start with specialized Tier 1 bytecode. See What's new in 3.11 for details.
When the Tier 1 bytecode gets hot enough, it gets translated to a new, purely internal Tier 2 IR, a.k.a. micro-ops ("uops").
The Tier 2 IR uses the same stack-based VM as Tier 1, but the instruction format is better suited to translation to machine code.
We have several optimization passes for Tier 2 IR, which are applied before it is interpreted or translated to machine code.
There is a Tier 2 interpreter, but it is mostly intended for debugging the earlier stages of the optimization pipeline. The Tier 2 interpreter can be enabled by configuring Python with
--enable-experimental-jit=interpreter
.When the JIT is enabled, the optimized Tier 2 IR is translated to machine code, which is then executed.
The machine code translation process uses a technique called copy-and-patch. It has no runtime dependencies, but there is a new build-time dependency on LLVM.
The --enable-experimental-jit
flag has the following optional values:
no
(default) -- Disable the entire Tier 2 and JIT pipeline.yes
(default if the flag is present without optional value) -- Enable the JIT. To disable the JIT at runtime, pass the environment variablePYTHON_JIT=0
.yes-off
-- Build the JIT but disable it by default. To enable the JIT at runtime, pass the environment variablePYTHON_JIT=1
.interpreter
-- Enable the Tier 2 interpreter but disable the JIT. The interpreter can be disabled by running withPYTHON_JIT=0
.
(On Windows, use PCbuild/build.bat --experimental-jit
to enable the JIT
or --experimental-jit-interpreter
to enable the Tier 2 interpreter.)
See PEP 744 for more details.
(JIT by Brandt Bucher, inspired by a paper by Haoran Xu and Fredrik Kjolstad. Tier 2 IR by Mark Shannon and Guido van Rossum. Tier 2 optimizer by Ken Jin.)
Free-threaded CPython¶
CPython will run with the global interpreter lock (GIL) disabled when
configured using the --disable-gil
option at build time. This is an
experimental feature and therefore isn't used by default. Users need to
either compile their own interpreter, or install one of the experimental
builds that are marked as free-threaded. See PEP 703 "Making the Global
Interpreter Lock Optional in CPython" for more detail.
Free-threaded execution allows for full utilization of the available processing power by running threads in parallel on available CPU cores. While not all software will benefit from this automatically, programs designed with threading in mind will run faster on multicore hardware.
Work is still ongoing: expect some bugs and a substantial single-threaded performance hit.
The free-threaded build still supports optionally running with the GIL
enabled at runtime using the environment variable PYTHON_GIL
or
the command line option -X gil
.
To check if the current interpreter is configured with --disable-gil
,
use sysconfig.get_config_var("Py_GIL_DISABLED")
. To check if the GIL
is actually disabled in the running process, the sys._is_gil_enabled()
function can be used.
C-API extension modules need to be built specifically for the free-threaded
build. Extensions that support running with the GIL disabled should
use the Py_mod_gil
slot. Extensions using single-phase init should
use PyUnstable_Module_SetGIL()
to indicate whether they support
running with the GIL disabled. Importing C extensions that don't use these
mechanisms will cause the GIL to be enabled, unless the GIL was explicitly
disabled with the PYTHON_GIL
environment variable or the
-X gil=0
option.
pip 24.1b1 or newer is required to install packages with C extensions in the free-threaded build.
Other Language Changes¶
The
exec()
andeval()
built-ins now accept theirglobals
andlocals
namespace arguments as keywords. (Contributed by Raphael Gaschignard in gh-105879)Allow the count argument of
str.replace()
to be a keyword. (Contributed by Hugo van Kemenade in gh-106487.)Compiler now strip indents from docstrings. This will reduce the size of bytecode cache (e.g.
.pyc
file). For example, cache file size forsqlalchemy.orm.session
in SQLAlchemy 2.0 is reduced by about 5%. This change will affect tools using docstrings, likedoctest
. (Contributed by Inada Naoki in gh-81283.)The
compile()
built-in can now accept a new flag,ast.PyCF_OPTIMIZED_AST
, which is similar toast.PyCF_ONLY_AST
except that the returnedAST
is optimized according to the value of theoptimize
argument. (Contributed by Irit Katriel in gh-108113).multiprocessing
,concurrent.futures
,compileall
: Replaceos.cpu_count()
withos.process_cpu_count()
to select the default number of worker threads and processes. Get the CPU affinity if supported. (Contributed by Victor Stinner in gh-109649.)os.path.realpath()
now resolves MS-DOS style file names even if the file is not accessible. (Contributed by Moonsik Park in gh-82367.)Fixed a bug where a
global
declaration in anexcept
block is rejected when the global is used in theelse
block. (Contributed by Irit Katriel in gh-111123.)Many functions now emit a warning if a boolean value is passed as a file descriptor argument. This can help catch some errors earlier. (Contributed by Serhiy Storchaka in gh-82626.)
Added a new environment variable
PYTHON_FROZEN_MODULES
. It determines whether or not frozen modules are ignored by the import machinery, equivalent of the-X frozen_modules
command-line option. (Contributed by Yilei Yang in gh-111374.)Add support for the perf profiler working without frame pointers through the new environment variable
PYTHON_PERF_JIT_SUPPORT
and command-line option-X perf_jit
(Contributed by Pablo Galindo in gh-118518.)The new
PYTHON_HISTORY
environment variable can be used to change the location of a.python_history
file. (Contributed by Levi Sabah, Zackery Spytz and Hugo van Kemenade in gh-73965.)Add
PythonFinalizationError
exception. This exception derived fromRuntimeError
is raised when an operation is blocked during the Python finalization.The following functions now raise PythonFinalizationError, instead of
RuntimeError
:(Contributed by Victor Stinner in gh-114570.)
Added
name
andmode
attributes for compressed and archived file-like objects in modulesbz2
,lzma
,tarfile
andzipfile
. (Contributed by Serhiy Storchaka in gh-115961.)Allow controlling Expat >=2.6.0 reparse deferral (CVE-2023-52425) by adding five new methods:
xml.sax.expatreader.ExpatParser.flush()
(Contributed by Sebastian Pipping in gh-115623.)
The
ssl.create_default_context()
API now includesssl.VERIFY_X509_PARTIAL_CHAIN
andssl.VERIFY_X509_STRICT
in its default flags.Note
ssl.VERIFY_X509_STRICT
may reject pre-RFC 5280 or malformed certificates that the underlying OpenSSL implementation otherwise would accept. While disabling this is not recommended, you can do so using:ctx = ssl.create_default_context() ctx.verify_flags &= ~ssl.VERIFY_X509_STRICT
(Contributed by William Woodruff in gh-112389.)
The
configparser.ConfigParser
now accepts unnamed sections before named ones if configured to do so. (Contributed by Pedro Sousa Lacerda in gh-66449.)annotation scope within class scopes can now contain lambdas and comprehensions. Comprehensions that are located within class scopes are not inlined into their parent scope. (Contributed by Jelle Zijlstra in gh-109118 and gh-118160.)
Classes have a new
__firstlineno__
attribute, populated by the compiler, with the line number of the first line of the class definition. (Contributed by Serhiy Storchaka in gh-118465.)from __future__ import ...
statements are now just normal relative imports if dots are present before the module name. (Contributed by Jeremiah Gabriel Pascual in gh-118216.)
New Modules¶
None.
Improved Modules¶
argparse¶
Add parameter deprecated in methods
add_argument()
andadd_parser()
which allows to deprecate command-line options, positional arguments and subcommands. (Contributed by Serhiy Storchaka in gh-83648.)
array¶
ast¶
The constructors of node types in the
ast
module are now stricter in the arguments they accept, and have more intuitive behaviour when arguments are omitted.If an optional field on an AST node is not included as an argument when constructing an instance, the field will now be set to
None
. Similarly, if a list field is omitted, that field will now be set to an empty list, and if aast.expr_context
field is omitted, it defaults toLoad()
. (Previously, in all cases, the attribute would be missing on the newly constructed AST node instance.)If other arguments are omitted, a
DeprecationWarning
is emitted. This will cause an exception in Python 3.15. Similarly, passing a keyword argument that does not map to a field on the AST node is now deprecated, and will raise an exception in Python 3.15.These changes do not apply to user-defined subclasses of
ast.AST
, unless the class opts in to the new behavior by setting the attributeast.AST._field_types
.(Contributed by Jelle Zijlstra in gh-105858, gh-117486, and gh-118851.)
ast.parse()
now accepts an optional argument optimize which is passed on to thecompile()
built-in. This makes it possible to obtain an optimized AST. (Contributed by Irit Katriel in gh-108113.)
asyncio¶
asyncio.loop.create_unix_server()
will now automatically remove the Unix socket when the server is closed. (Contributed by Pierre Ossman in gh-111246.)asyncio.DatagramTransport.sendto()
will now send zero-length datagrams if called with an empty bytes object. The transport flow control also now accounts for the datagram header when calculating the buffer size. (Contributed by Jamie Phan in gh-115199.)Add
asyncio.Server.close_clients()
andasyncio.Server.abort_clients()
methods which allow to more forcefully close an asyncio server. (Contributed by Pierre Ossman in gh-113538.)asyncio.as_completed()
now returns an object that is both an asynchronous iterator and a plain iterator of awaitables. The awaitables yielded by asynchronous iteration include original task or future objects that were passed in, making it easier to associate results with the tasks being completed. (Contributed by Justin Arthur in gh-77714.)When
asyncio.TaskGroup.create_task()
is called on an inactiveasyncio.TaskGroup
, the given coroutine will be closed (which prevents aRuntimeWarning
about the given coroutine being never awaited). (Contributed by Arthur Tacca and Jason Zhang in gh-115957.)Improved behavior of
asyncio.TaskGroup
when an external cancellation collides with an internal cancellation. For example, when two task groups are nested and both experience an exception in a child task simultaneously, it was possible that the outer task group would hang, because its internal cancellation was swallowed by the inner task group.In the case where a task group is cancelled externally and also must raise an
ExceptionGroup
, it will now call the parent task'scancel()
method. This ensures that aasyncio.CancelledError
will be raised at the nextawait
, so the cancellation is not lost.An added benefit of these changes is that task groups now preserve the cancellation count (
asyncio.Task.cancelling()
).In order to handle some corner cases,
asyncio.Task.uncancel()
may now reset the undocumented_must_cancel
flag when the cancellation count reaches zero.(Inspired by an issue reported by Arthur Tacca in gh-116720.)
Add
asyncio.Queue.shutdown()
(along withasyncio.QueueShutDown
) for queue termination. (Contributed by Laurie Opperman and Yves Duprat in gh-104228.)Accept a tuple of separators in
asyncio.StreamReader.readuntil()
, stopping when one of them is encountered. (Contributed by Bruce Merry in gh-81322.)
base64¶
Add
base64.z85encode()
andbase64.z85decode()
functions which allow encoding and decoding Z85 data. See Z85 specification for more information. (Contributed by Matan Perelman in gh-75299.)
copy¶
Add
copy.replace()
function which allows to create a modified copy of an object, which is especially useful for immutable objects. It supports named tuples created with the factory functioncollections.namedtuple()
,dataclass
instances, variousdatetime
objects,Signature
objects,Parameter
objects, code object, and any user classes which define the__replace__()
method. (Contributed by Serhiy Storchaka in gh-108751.)
dbm¶
Add
dbm.gnu.gdbm.clear()
anddbm.ndbm.ndbm.clear()
methods that remove all items from the database. (Contributed by Donghee Na in gh-107122.)Add new
dbm.sqlite3
backend, and make it the defaultdbm
backend. (Contributed by Raymond Hettinger and Erlend E. Aasland in gh-100414.)
dis¶
Change the output of
dis
module functions to show logical labels for jump targets and exception handlers, rather than offsets. The offsets can be added with the new-O
command line option or theshow_offsets
parameter. (Contributed by Irit Katriel in gh-112137.)get_instructions()
no longer represents cache entries as separate instructions. Instead, it returns them as part of theInstruction
, in the new cache_info field. The show_caches argument toget_instructions()
is deprecated and no longer has any effect. (Contributed by Irit Katriel in gh-112962.)
doctest¶
Color is added to the output by default. This can be controlled via the new
PYTHON_COLORS
environment variable as well as the canonicalNO_COLOR
andFORCE_COLOR
environment variables. See also Controlling color. (Contributed by Hugo van Kemenade in gh-117225.)The
doctest.DocTestRunner.run()
method now counts the number of skipped tests. Adddoctest.DocTestRunner.skips
anddoctest.TestResults.skipped
attributes. (Contributed by Victor Stinner in gh-108794.)
email¶
Headers with embedded newlines are now quoted on output.
The
generator
will now refuse to serialize (write) headers that are improperly folded or delimited, such that they would be parsed as multiple headers or joined with adjacent data. If you need to turn this safety feature off, setverify_generated_headers
. (Contributed by Bas Bloemsaat and Petr Viktorin in gh-121650.)email.utils.getaddresses()
andemail.utils.parseaddr()
now return('', '')
2-tuples in more situations where invalid email addresses are encountered instead of potentially inaccurate values. Add optional strict parameter to these two functions: usestrict=False
to get the old behavior, accept malformed inputs.getattr(email.utils, 'supports_strict_parsing', False)
can be used to check if the strict parameter is available. (Contributed by Thomas Dwyer and Victor Stinner for gh-102988 to improve the CVE-2023-27043 fix.)
fractions¶
Formatting for objects of type
fractions.Fraction
now supports the standard format specification mini-language rules for fill, alignment, sign handling, minimum width and grouping. (Contributed by Mark Dickinson in gh-111320.)
gc¶
The cyclic garbage collector is now incremental, which changes the meanings of the results of
gc.get_threshold()
andgc.set_threshold()
as well asgc.get_count()
andgc.get_stats()
.gc.get_threshold()
returns a three-item tuple for backwards compatibility. The first value is the threshold for young collections, as before; the second value determines the rate at which the old collection is scanned (the default is 10, and higher values mean that the old collection is scanned more slowly). The third value is meaningless and is always zero.gc.set_threshold()
ignores any items after the second.gc.get_count()
andgc.get_stats()
return the same format of results as before. The only difference is that instead of the results referring to the young, aging and old generations, the results refer to the young generation and the aging and collecting spaces of the old generation.
In summary, code that attempted to manipulate the behavior of the cycle GC may not work exactly as intended, but it is very unlikely to be harmful. All other code will work just fine.
glob¶
Add
glob.translate()
function that converts a path specification with shell-style wildcards to a regular expression. (Contributed by Barney Gale in gh-72904.)
importlib¶
Previously deprecated
importlib.resources
functions are un-deprecated:All now allow for a directory (or tree) of resources, using multiple positional arguments.
For text-reading functions, the encoding and errors must now be given as keyword arguments.
The
contents()
remains deprecated in favor of the full-featuredTraversable
API. However, there is now no plan to remove it.(Contributed by Petr Viktorin in gh-106532.)
io¶
The
io.IOBase
finalizer now logs theclose()
method errors withsys.unraisablehook
. Previously, errors were ignored silently by default, and only logged in Python Development Mode or on Python built on debug mode. (Contributed by Victor Stinner in gh-62948.)
ipaddress¶
Add the
ipaddress.IPv4Address.ipv6_mapped
property, which returns the IPv4-mapped IPv6 address. (Contributed by Charles Machalow in gh-109466.)Fix
is_global
andis_private
behavior inIPv4Address
,IPv6Address
,IPv4Network
andIPv6Network
.
itertools¶
Added a
strict
option toitertools.batched()
. This raises aValueError
if the final batch is shorter than the specified batch size. (Contributed by Raymond Hettinger in gh-113202.)
marshal¶
Add the allow_code parameter in module functions. Passing
allow_code=False
prevents serialization and de-serialization of code objects which are incompatible between Python versions. (Contributed by Serhiy Storchaka in gh-113626.)
math¶
A new function
fma()
for fused multiply-add operations has been added. This function computesx * y + z
with only a single round, and so avoids any intermediate loss of precision. It wraps thefma()
function provided by C99, and follows the specification of the IEEE 754 "fusedMultiplyAdd" operation for special cases. (Contributed by Mark Dickinson and Victor Stinner in gh-73468.)
mimetypes¶
Add the
guess_file_type()
function which works with file path. Passing file path instead of URL inguess_type()
is soft deprecated. (Contributed by Serhiy Storchaka in gh-66543.)
mmap¶
The
mmap.mmap
class now has anseekable()
method that can be used when a seekable file-like object is required. Theseek()
method now returns the new absolute position. (Contributed by Donghee Na and Sylvie Liberman in gh-111835.)mmap.mmap
now has a trackfd parameter on Unix; if it isFalse
, the file descriptor specified by fileno will not be duplicated. (Contributed by Zackery Spytz and Petr Viktorin in gh-78502.)mmap.mmap
is now protected from crashing on Windows when the mapped memory is inaccessible due to file system errors or access violations. (Contributed by Jannis Weigend in gh-118209.)
opcode¶
Move
opcode.ENABLE_SPECIALIZATION
to_opcode.ENABLE_SPECIALIZATION
. This field was added in 3.12, it was never documented and is not intended for external usage. (Contributed by Irit Katriel in gh-105481.)Removed
opcode.is_pseudo
,opcode.MIN_PSEUDO_OPCODE
andopcode.MAX_PSEUDO_OPCODE
, which were added in 3.12, were never documented or exposed throughdis
, and were not intended to be used externally.
os¶
Add
os.process_cpu_count()
function to get the number of logical CPUs usable by the calling thread of the current process. (Contributed by Victor Stinner in gh-109649.)Add a low level interface for Linux's timer notification file descriptors via
os.timerfd_create()
,os.timerfd_settime()
,os.timerfd_settime_ns()
,os.timerfd_gettime()
, andos.timerfd_gettime_ns()
,os.TFD_NONBLOCK
,os.TFD_CLOEXEC
,os.TFD_TIMER_ABSTIME
, andos.TFD_TIMER_CANCEL_ON_SET
(Contributed by Masaru Tsuchiyama in gh-108277.)os.cpu_count()
andos.process_cpu_count()
can be overridden through the new environment variablePYTHON_CPU_COUNT
or the new command-line option-X cpu_count
. This option is useful for users who need to limit CPU resources of a container system without having to modify the container (application code). (Contributed by Donghee Na in gh-109595.)Add support of
os.lchmod()
and the follow_symlinks argument inos.chmod()
on Windows. Note that the default value of follow_symlinks inos.lchmod()
isFalse
on Windows. (Contributed by Serhiy Storchaka in gh-59616.)Add support of
os.fchmod()
and a file descriptor inos.chmod()
on Windows. (Contributed by Serhiy Storchaka in gh-113191.)os.posix_spawn()
now acceptsenv=None
, which makes the newly spawned process use the current process environment. (Contributed by Jakub Kulik in gh-113119.)os.posix_spawn()
gains anos.POSIX_SPAWN_CLOSEFROM
attribute for use infile_actions=
on platforms that supportposix_spawn_file_actions_addclosefrom_np()
. (Contributed by Jakub Kulik in gh-113117.)os.mkdir()
andos.makedirs()
on Windows now support passing a mode value of0o700
to apply access control to the new directory. This implicitly affectstempfile.mkdtemp()
and is a mitigation for CVE-2024-4030. Other values for mode continue to be ignored. (Contributed by Steve Dower in gh-118486.)
os.path¶
Add
os.path.isreserved()
to check if a path is reserved on the current system. This function is only available on Windows. (Contributed by Barney Gale in gh-88569.)On Windows,
os.path.isabs()
no longer considers paths starting with exactly one (back)slash to be absolute. (Contributed by Barney Gale and Jon Foster in gh-44626.)Add support of dir_fd and follow_symlinks keyword arguments in
shutil.chown()
. (Contributed by Berker Peksag and Tahia K in gh-62308)
pathlib¶
Add
pathlib.UnsupportedOperation
, which is raised instead ofNotImplementedError
when a path operation isn't supported. (Contributed by Barney Gale in gh-89812.)Add
pathlib.Path.from_uri()
, a new constructor to create apathlib.Path
object from a 'file' URI (file://
). (Contributed by Barney Gale in gh-107465.)Add
pathlib.PurePath.full_match()
for matching paths with shell-style wildcards, including the recursive wildcard "**
". (Contributed by Barney Gale in gh-73435.)Add
pathlib.PurePath.parser
class attribute that stores the implementation ofos.path
used for low-level path parsing and joining: eitherposixpath
orntpath
.Add recurse_symlinks keyword-only argument to
pathlib.Path.glob()
andrglob()
. (Contributed by Barney Gale in gh-77609.)Add follow_symlinks keyword-only argument to
is_file()
,is_dir()
,owner()
,group()
. (Contributed by Barney Gale in gh-105793, and Kamil Turek in gh-107962.)Return files and directories from
pathlib.Path.glob()
andrglob()
when given a pattern that ends with "**
". In earlier versions, only directories were returned. (Contributed by Barney Gale in gh-70303.)
pdb¶
Add ability to move between chained exceptions during post mortem debugging in
pm()
using the newexceptions [exc_number]
command for Pdb. (Contributed by Matthias Bussonnier in gh-106676.)Expressions/statements whose prefix is a pdb command are now correctly identified and executed. (Contributed by Tian Gao in gh-108464.)
sys.path[0]
will no longer be replaced by the directory of the script being debugged whensys.flags.safe_path
is set (via the-P
command line option orPYTHONSAFEPATH
environment variable). (Contributed by Tian Gao and Christian Walther in gh-111762.)zipapp
is supported as a debugging target. (Contributed by Tian Gao in gh-118501.)breakpoint()
andpdb.set_trace()
now enter the debugger immediately rather than on the next line of code to be executed. This change prevents the debugger from breaking outside of the context whenbreakpoint()
is positioned at the end of the context. (Contributed by Tian Gao in gh-118579.)
queue¶
Add
queue.Queue.shutdown()
(along withqueue.ShutDown
) for queue termination. (Contributed by Laurie Opperman and Yves Duprat in gh-104750.)
random¶
Add a command-line interface. (Contributed by Hugo van Kemenade in gh-118131.)
re¶
Rename
re.error
tore.PatternError
for improved clarity.re.error
is kept for backward compatibility.
site¶
.pth
files are now decoded by UTF-8 first, and then by the locale encoding if the UTF-8 decoding fails. (Contributed by Inada Naoki in gh-117802.)
sqlite3¶
A
ResourceWarning
is now emitted if asqlite3.Connection
object is notclosed
explicitly. (Contributed by Erlend E. Aasland in gh-105539.)Add filter keyword-only parameter to
sqlite3.Connection.iterdump()
for filtering database objects to dump. (Contributed by Mariusz Felisiak in gh-91602.)
statistics¶
Add
statistics.kde()
for kernel density estimation. This makes it possible to estimate a continuous probability density function from a fixed number of discrete samples. Also addedstatistics.kde_random()
for sampling from the estimated probability density function. (Contributed by Raymond Hettinger in gh-115863.)
subprocess¶
The
subprocess
module now uses theos.posix_spawn()
function in more situations. Notably in the default case ofclose_fds=True
on more recent versions of platforms including Linux, FreeBSD, and Solaris where the C library providesposix_spawn_file_actions_addclosefrom_np()
. On Linux this should perform similar to our existing Linuxvfork()
based code. A private control knobsubprocess._USE_POSIX_SPAWN
can be set toFalse
if you need to forcesubprocess
not to ever useos.posix_spawn()
. Please report your reason and platform details in the CPython issue tracker if you set this so that we can improve our API selection logic for everyone. (Contributed by Jakub Kulik in gh-113117.)
sys¶
Add the
sys._is_interned()
function to test if the string was interned. This function is not guaranteed to exist in all implementations of Python. (Contributed by Serhiy Storchaka in gh-78573.)
tempfile¶
On Windows, the default mode
0o700
used bytempfile.mkdtemp()
now limits access to the new directory due to changes toos.mkdir()
. This is a mitigation for CVE-2024-4030. (Contributed by Steve Dower in gh-118486.)
time¶
On Windows,
time.monotonic()
now uses theQueryPerformanceCounter()
clock to have a resolution better than 1 us, instead of theGetTickCount64()
clock which has a resolution of 15.6 ms. (Contributed by Victor Stinner in gh-88494.)On Windows,
time.time()
now uses theGetSystemTimePreciseAsFileTime()
clock to have a resolution better than 1 μs, instead of theGetSystemTimeAsFileTime()
clock which has a resolution of 15.6 ms. (Contributed by Victor Stinner in gh-63207.)
tkinter¶
Add
tkinter
widget methods:tk_busy_hold()
,tk_busy_configure()
,tk_busy_cget()
,tk_busy_forget()
,tk_busy_current()
, andtk_busy_status()
. (Contributed by Miguel, klappnase and Serhiy Storchaka in gh-72684.)The
tkinter
widget methodwm_attributes()
now accepts the attribute name without the minus prefix to get window attributes, e.g.w.wm_attributes('alpha')
and allows to specify attributes and values to set as keyword arguments, e.g.w.wm_attributes(alpha=0.5)
. Add new optional keyword-only parameter return_python_dict: callingw.wm_attributes(return_python_dict=True)
returns the attributes as a dict instead of a tuple. (Contributed by Serhiy Storchaka in gh-43457.)Add new optional keyword-only parameter return_ints in the
Text.count()
method. Passingreturn_ints=True
makes it always returning the single count as an integer instead of a 1-tuple orNone
. (Contributed by Serhiy Storchaka in gh-97928.)Add support of the "vsapi" element type in the
element_create()
method oftkinter.ttk.Style
. (Contributed by Serhiy Storchaka in gh-68166.)Add the
after_info()
method for Tkinter widgets. (Contributed by Cheryl Sabella in gh-77020.)Add the
PhotoImage
methodcopy_replace()
to copy a region from one image to other image, possibly with pixel zooming and/or subsampling. Add from_coords parameter toPhotoImage
methodscopy()
,zoom()
andsubsample()
. Add zoom and subsample parameters toPhotoImage
methodcopy()
. (Contributed by Serhiy Storchaka in gh-118225.)Add the
PhotoImage
methodsread()
to read an image from a file anddata()
to get the image data. Add background and grayscale parameters toPhotoImage
methodwrite()
. (Contributed by Serhiy Storchaka in gh-118271.)
traceback¶
Add show_group parameter to
traceback.TracebackException.format_exception_only()
to format the nested exceptions of aBaseExceptionGroup
instance, recursively. (Contributed by Irit Katriel in gh-105292.)Add the field exc_type_str to
TracebackException
, which holds a string display of the exc_type. Deprecate the field exc_type which holds the type object itself. Add parameter save_exc_type (defaultTrue
) to indicate whetherexc_type
should be saved. (Contributed by Irit Katriel in gh-112332.)
types¶
SimpleNamespace
constructor now allows specifying initial values of attributes as a positional argument which must be a mapping or an iterable of key-value pairs. (Contributed by Serhiy Storchaka in gh-108191.)
typing¶
Add
typing.get_protocol_members()
to return the set of members defining atyping.Protocol
. Addtyping.is_protocol()
to check whether a class is atyping.Protocol
. (Contributed by Jelle Zijlstra in gh-104873.)Add
typing.ReadOnly
, a special typing construct to mark an item of atyping.TypedDict
as read-only for type checkers. See PEP 705 for more details.Add
typing.NoDefault
, a sentinel object used to represent the defaults of some parameters in thetyping
module. (Contributed by Jelle Zijlstra in gh-116126.)
unicodedata¶
The Unicode database has been updated to version 15.1.0. (Contributed by James Gerity in gh-109559.)
venv¶
Add support for adding source control management (SCM) ignore files to a virtual environment's directory. By default, Git is supported. This is implemented as opt-in via the API which can be extended to support other SCMs (
venv.EnvBuilder
andvenv.create()
), and opt-out via the CLI (using--without-scm-ignore-files
). (Contributed by Brett Cannon in gh-108125.)
warnings¶
The new
warnings.deprecated()
decorator provides a way to communicate deprecations to static type checkers and to warn on usage of deprecated classes and functions. A runtime deprecation warning may also be emitted when a decorated function or class is used at runtime. See PEP 702. (Contributed by Jelle Zijlstra in gh-104003.)
xml.etree.ElementTree¶
Add the
close()
method for the iterator returned byiterparse()
for explicit cleaning up. (Contributed by Serhiy Storchaka in gh-69893.)
zipimport¶
Gains support for ZIP64 format files. Everybody loves huge code right? (Contributed by Tim Hatch in gh-94146.)
Optimizations¶
textwrap.indent()
is now ~30% faster than before for large input. (Contributed by Inada Naoki in gh-107369.)The
subprocess
module usesos.posix_spawn()
in more situations including the default whereclose_fds=True
on many modern platforms. This should provide a noteworthy performance increase launching processes on FreeBSD and Solaris. See the subprocess section above for details. (Contributed by Jakub Kulik in gh-113117.)Several standard library modules have had their import times significantly improved. For example, the import time of the
typing
module has been reduced by around a third by removing dependencies onre
andcontextlib
. Other modules to enjoy import-time speedups includeimportlib.metadata
,threading
,enum
,functools
andemail.utils
. (Contributed by Alex Waygood, Shantanu Jain, Adam Turner, Daniel Hollas and others in gh-109653.)
Removed Modules And APIs¶
PEP 594: dead batteries (and other module removals)¶
PEP 594 removed 19 modules from the standard library, deprecated in Python 3.11:
aifc
. (Contributed by Victor Stinner in gh-104773.)audioop
. (Contributed by Victor Stinner in gh-104773.)chunk
. (Contributed by Victor Stinner in gh-104773.)cgi
andcgitb
.cgi.FieldStorage
can typically be replaced withurllib.parse.parse_qsl()
forGET
andHEAD
requests, and theemail.message
module or multipart PyPI project forPOST
andPUT
.cgi.parse()
can be replaced by callingurllib.parse.parse_qs()
directly on the desired query string, except formultipart/form-data
input, which can be handled as described forcgi.parse_multipart()
.cgi.parse_header()
can be replaced with the functionality in theemail
package, which implements the same MIME RFCs. For example, withemail.message.EmailMessage
:from email.message import EmailMessage msg = EmailMessage() msg['content-type'] = 'application/json; charset="utf8"' main, params = msg.get_content_type(), msg['content-type'].params
cgi.parse_multipart()
can be replaced with the functionality in theemail
package (e.g.email.message.EmailMessage
andemail.message.Message
) which implements the same MIME RFCs, or with the multipart PyPI project.
(Contributed by Victor Stinner in gh-104773.)
crypt
module and its private_crypt
extension. Thehashlib
module is a potential replacement for certain use cases. Otherwise, the following PyPI projects can be used:bcrypt: Modern password hashing for your software and your servers.
passlib: Comprehensive password hashing framework supporting over 30 schemes.
argon2-cffi: The secure Argon2 password hashing algorithm.
legacycrypt:
ctypes
wrapper to the POSIX crypt library call and associated functionality.crypt_r: Fork of the
crypt
module, wrapper to the crypt_r(3) library call and associated functionality.
(Contributed by Victor Stinner in gh-104773.)
imghdr
: use the projects filetype, puremagic, or python-magic instead. Thepuremagic.what()
function can be used to replace theimghdr.what()
function for all file formats that were supported byimghdr
. (Contributed by Victor Stinner in gh-104773.)mailcap
. Themimetypes
module provides an alternative. (Contributed by Victor Stinner in gh-104773.)msilib
. (Contributed by Zachary Ware in gh-104773.)nis
. (Contributed by Victor Stinner in gh-104773.)nntplib
: the nntplib PyPI project can be used instead. (Contributed by Victor Stinner in gh-104773.)ossaudiodev
: use the pygame project for audio playback. (Contributed by Victor Stinner in gh-104780.)pipes
: use thesubprocess
module instead. (Contributed by Victor Stinner in gh-104773.)sndhdr
: use the projects filetype, puremagic, or python-magic instead. (Contributed by Victor Stinner in gh-104773.)spwd
: the python-pam project can be used instead. (Contributed by Victor Stinner in gh-104773.)sunau
. (Contributed by Victor Stinner in gh-104773.)telnetlib
, use the projects telnetlib3 or Exscript instead. (Contributed by Victor Stinner in gh-104773.)uu
: thebase64
module is a modern alternative. (Contributed by Victor Stinner in gh-104773.)xdrlib
. (Contributed by Victor Stinner in gh-104773.)
Remove the
2to3
program and thelib2to3
module, deprecated in Python 3.11. (Contributed by Victor Stinner in gh-104780.)Remove the
tkinter.tix
module, deprecated in Python 3.6. The third-party Tix library which the module wrapped is unmaintained. (Contributed by Zachary Ware in gh-75552.)
configparser¶
Remove the undocumented
configparser.LegacyInterpolation
class, deprecated in the docstring since Python 3.2, and with a deprecation warning since Python 3.11. (Contributed by Hugo van Kemenade in gh-104886.)
importlib¶
Remove deprecated
__getitem__()
access forimportlib.metadata.EntryPoint
objects. (Contributed by Jason R. Coombs in gh-113175.)
locale¶
Remove
locale.resetlocale()
function deprecated in Python 3.11: uselocale.setlocale(locale.LC_ALL, "")
instead. (Contributed by Victor Stinner in gh-104783.)
logging¶
logging
: Remove undocumented and untestedLogger.warn()
andLoggerAdapter.warn()
methods andlogging.warn()
function. Deprecated since Python 3.3, they were aliases to thelogging.Logger.warning()
method,logging.LoggerAdapter.warning()
method andlogging.warning()
function. (Contributed by Victor Stinner in gh-105376.)
pathlib¶
Remove support for using
pathlib.Path
objects as context managers. This functionality was deprecated and made a no-op in Python 3.9.
re¶
Remove undocumented, never working, and deprecated
re.template
function andre.TEMPLATE
flag (andre.T
alias). (Contributed by Serhiy Storchaka and Nikita Sobolev in gh-105687.)
turtle¶
Remove the
turtle.RawTurtle.settiltangle()
method, deprecated in docs since Python 3.1 and with a deprecation warning since Python 3.11. (Contributed by Hugo van Kemenade in gh-104876.)
typing¶
Namespaces
typing.io
andtyping.re
, deprecated in Python 3.8, are now removed. The items in those namespaces can be imported directly fromtyping
. (Contributed by Sebastian Rittau in gh-92871.)Remove support for the keyword-argument method of creating
typing.TypedDict
types, deprecated in Python 3.11. (Contributed by Tomas Roun in gh-104786.)
unittest¶
Remove the following
unittest
functions, deprecated in Python 3.11:unittest.findTestCases()
unittest.makeSuite()
unittest.getTestCaseNames()
Use
TestLoader
methods instead:(Contributed by Hugo van Kemenade in gh-104835.)
Remove the untested and undocumented
unittest.TestProgram.usageExit()
method, deprecated in Python 3.11. (Contributed by Hugo van Kemenade in gh-104992.)
urllib¶
Remove cafile, capath and cadefault parameters of the
urllib.request.urlopen()
function, deprecated in Python 3.6: pass the context parameter instead. Usessl.SSLContext.load_cert_chain()
to load specific certificates, or letssl.create_default_context()
select the system's trusted CA certificates for you. (Contributed by Victor Stinner in gh-105382.)
webbrowser¶
Remove the untested and undocumented
webbrowser
MacOSX
class, deprecated in Python 3.11. Use theMacOSXOSAScript
class (introduced in Python 3.2) instead. (Contributed by Hugo van Kemenade in gh-104804.)Remove deprecated
webbrowser.MacOSXOSAScript._name
attribute. Usewebbrowser.MacOSXOSAScript.name
attribute instead. (Contributed by Nikita Sobolev in gh-105546.)
New Deprecations¶
Removed chained
classmethod
descriptors (introduced in gh-63272). This can no longer be used to wrap other descriptors such asproperty
. The core design of this feature was flawed and caused a number of downstream problems. To "pass-through" aclassmethod
, consider using the__wrapped__
attribute that was added in Python 3.10. (Contributed by Raymond Hettinger in gh-89519.)array
:array
's'u'
format code, deprecated in docs since Python 3.3, emitsDeprecationWarning
since 3.13 and will be removed in Python 3.16. Use the'w'
format code instead. (Contributed by Hugo van Kemenade in gh-80480.)ctypes
: Deprecate undocumentedctypes.SetPointerType()
function. Soft-deprecate thectypes.ARRAY()
function in favor of multiplication. (Contributed by Victor Stinner in gh-105733.)decimal
: Deprecate non-standard format specifier "N" fordecimal.Decimal
. It was not documented and only supported in the C implementation. (Contributed by Serhiy Storchaka in gh-89902.)dis
: Thedis.HAVE_ARGUMENT
separator is deprecated. Check membership inhasarg
instead. (Contributed by Irit Katriel in gh-109319.)Objets cadres: Calling
frame.clear()
on a suspended frame raisesRuntimeError
(as has always been the case for an executing frame). (Contributed by Irit Katriel in gh-79932.)getopt
andoptparse
modules: They are now soft deprecated: theargparse
module should be used for new projects. Previously, theoptparse
module was already deprecated, its removal was not scheduled, and no warnings was emitted: so there is no change in practice. (Contributed by Victor Stinner in gh-106535.)gettext
: Emit deprecation warning for non-integer numbers ingettext
functions and methods that consider plural forms even if the translation was not found. (Contributed by Serhiy Storchaka in gh-88434.)glob
: The undocumentedglob.glob0()
andglob.glob1()
functions are deprecated. Useglob.glob()
and pass a directory to its root_dir argument instead. (Contributed by Barney Gale in gh-117337.)http.server
:http.server.CGIHTTPRequestHandler
now emits aDeprecationWarning
as it will be removed in 3.15. Process-based CGI HTTP servers have been out of favor for a very long time. This code was outdated, unmaintained, and rarely used. It has a high potential for both security and functionality bugs. This includes removal of the--cgi
flag to thepython -m http.server
command line in 3.15.mimetypes
: Passing file path instead of URL inguess_type()
is soft deprecated. Useguess_file_type()
instead. (Contributed by Serhiy Storchaka in gh-66543.)re
: Passing optional arguments maxsplit, count and flags in module-level functionsre.split()
,re.sub()
andre.subn()
as positional arguments is now deprecated. In future Python versions these parameters will be keyword-only. (Contributed by Serhiy Storchaka in gh-56166.)pathlib
:pathlib.PurePath.is_reserved()
is deprecated and scheduled for removal in Python 3.15. Useos.path.isreserved()
to detect reserved paths on Windows.platform
:java_ver()
is deprecated and will be removed in 3.15. It was largely untested, had a confusing API, and was only useful for Jython support. (Contributed by Nikita Sobolev in gh-116349.)pydoc
: Deprecate undocumentedpydoc.ispackage()
function. (Contributed by Zackery Spytz in gh-64020.)sqlite3
: Passing more than one positional argument tosqlite3.connect()
and thesqlite3.Connection
constructor is deprecated. The remaining parameters will become keyword-only in Python 3.15.Deprecate passing name, number of arguments, and the callable as keyword arguments for the following
sqlite3.Connection
APIs:Deprecate passing the callback callable by keyword for the following
sqlite3.Connection
APIs:The affected parameters will become positional-only in Python 3.15.
(Contributed by Erlend E. Aasland in gh-107948 and gh-108278.)
sys
:sys._enablelegacywindowsfsencoding()
function. Replace it with thePYTHONLEGACYWINDOWSFSENCODING
environment variable. (Contributed by Inada Naoki in gh-73427.)tarfile
: The undocumented and unusedtarfile
attribute oftarfile.TarFile
is deprecated and scheduled for removal in Python 3.16.traceback
: The field exc_type oftraceback.TracebackException
is deprecated. Use exc_type_str instead.-
Creating a
typing.NamedTuple
class using keyword arguments to denote the fields (NT = NamedTuple("NT", x=int, y=int)
) is deprecated, and will be disallowed in Python 3.15. Use the class-based syntax or the functional syntax instead. (Contributed by Alex Waygood in gh-105566.)When using the functional syntax to create a
typing.NamedTuple
class or atyping.TypedDict
class, failing to pass a value to the 'fields' parameter (NT = NamedTuple("NT")
orTD = TypedDict("TD")
) is deprecated. PassingNone
to the 'fields' parameter (NT = NamedTuple("NT", None)
orTD = TypedDict("TD", None)
) is also deprecated. Both will be disallowed in Python 3.15. To create a NamedTuple class with 0 fields, useclass NT(NamedTuple): pass
orNT = NamedTuple("NT", [])
. To create a TypedDict class with 0 fields, useclass TD(TypedDict): pass
orTD = TypedDict("TD", {})
. (Contributed by Alex Waygood in gh-105566 and gh-105570.)typing.no_type_check_decorator()
is deprecated, and scheduled for removal in Python 3.15. After eight years in thetyping
module, it has yet to be supported by any major type checkers. (Contributed by Alex Waygood in gh-106309.)typing.AnyStr
is deprecated. In Python 3.16, it will be removed fromtyping.__all__
, and aDeprecationWarning
will be emitted when it is imported or accessed. It will be removed entirely in Python 3.18. Use the new type parameter syntax instead. (Contributed by Michael The in gh-107116.)
Fonctions définies par l'utilisateur: Assignment to a function's
__code__
attribute where the new code object's type does not match the function's type, is deprecated. The different types are: plain function, generator, async generator and coroutine. (Contributed by Irit Katriel in gh-81137.)wave
: Deprecate thegetmark()
,setmark()
andgetmarkers()
methods of thewave.Wave_read
andwave.Wave_write
classes. They will be removed in Python 3.15. (Contributed by Victor Stinner in gh-105096.)
Pending Removal in Python 3.14¶
argparse
: The type, choices, and metavar parameters ofargparse.BooleanOptionalAction
are deprecated and will be removed in 3.14. (Contributed by Nikita Sobolev in gh-92248.)ast
: The following features have been deprecated in documentation since Python 3.8, now cause aDeprecationWarning
to be emitted at runtime when they are accessed or used, and will be removed in Python 3.14:ast.Num
ast.Str
ast.Bytes
ast.NameConstant
ast.Ellipsis
Use
ast.Constant
instead. (Contributed by Serhiy Storchaka in gh-90953.)-
The child watcher classes
MultiLoopChildWatcher
,FastChildWatcher
,AbstractChildWatcher
andSafeChildWatcher
are deprecated and will be removed in Python 3.14. (Contributed by Kumar Aditya in gh-94597.)asyncio.set_child_watcher()
,asyncio.get_child_watcher()
,asyncio.AbstractEventLoopPolicy.set_child_watcher()
andasyncio.AbstractEventLoopPolicy.get_child_watcher()
are deprecated and will be removed in Python 3.14. (Contributed by Kumar Aditya in gh-94597.)The
get_event_loop()
method of the default event loop policy now emits aDeprecationWarning
if there is no current event loop set and it decides to create one. (Contributed by Serhiy Storchaka and Guido van Rossum in gh-100160.)
collections.abc
: DeprecatedByteString
. PreferSequence
orBuffer
. For use in typing, prefer a union, likebytes | bytearray
, orcollections.abc.Buffer
. (Contributed by Shantanu Jain in gh-91896.)email
: Deprecated the isdst parameter inemail.utils.localtime()
. (Contributed by Alan Williams in gh-72346.)importlib
:__package__
and__cached__
will cease to be set or taken into consideration by the import system (gh-97879).importlib.abc
deprecated classes:importlib.abc.ResourceReader
importlib.abc.Traversable
importlib.abc.TraversableResources
Use
importlib.resources.abc
classes instead:(Contributed by Jason R. Coombs and Hugo van Kemenade in gh-93963.)
itertools
had undocumented, inefficient, historically buggy, and inconsistent support for copy, deepcopy, and pickle operations. This will be removed in 3.14 for a significant reduction in code volume and maintenance burden. (Contributed by Raymond Hettinger in gh-101588.)multiprocessing
: The default start method will change to a safer one on Linux, BSDs, and other non-macOS POSIX platforms where'fork'
is currently the default (gh-84559). Adding a runtime warning about this was deemed too disruptive as the majority of code is not expected to care. Use theget_context()
orset_start_method()
APIs to explicitly specify when your code requires'fork'
. See Contextes et méthodes de démarrage.pathlib
:is_relative_to()
andrelative_to()
: passing additional arguments is deprecated.pkgutil
:find_loader()
andget_loader()
now raiseDeprecationWarning
; useimportlib.util.find_spec()
instead. (Contributed by Nikita Sobolev in gh-97850.)pty
:master_open()
: usepty.openpty()
.slave_open()
: usepty.openpty()
.
-
version
andversion_info
.execute()
andexecutemany()
if named placeholders are used and parameters is a sequence instead of adict
.date and datetime adapter, date and timestamp converter: see the
sqlite3
documentation for suggested replacement recipes.
types.CodeType
: Accessingco_lnotab
was deprecated in PEP 626 since 3.10 and was planned to be removed in 3.12, but it only got a properDeprecationWarning
in 3.12. May be removed in 3.14. (Contributed by Nikita Sobolev in gh-101866.)typing
:ByteString
, deprecated since Python 3.9, now causes aDeprecationWarning
to be emitted when it is used.urllib
:urllib.parse.Quoter
is deprecated: it was not intended to be a public API. (Contributed by Gregory P. Smith in gh-88168.)
Pending Removal in Python 3.15¶
http.server.CGIHTTPRequestHandler
will be removed along with its related--cgi
flag topython -m http.server
. It was obsolete and rarely used. No direct replacement exists. Anything is better than CGI to interface a web server with a request handler.locale
:locale.getdefaultlocale()
was deprecated in Python 3.11 and originally planned for removal in Python 3.13 (gh-90817), but removal has been postponed to Python 3.15. Uselocale.setlocale()
,locale.getencoding()
andlocale.getlocale()
instead. (Contributed by Hugo van Kemenade in gh-111187.)pathlib
:pathlib.PurePath.is_reserved()
is deprecated and scheduled for removal in Python 3.15. Useos.path.isreserved()
to detect reserved paths on Windows.platform
:java_ver()
is deprecated and will be removed in 3.15. It was largely untested, had a confusing API, and was only useful for Jython support. (Contributed by Nikita Sobolev in gh-116349.)threading
: Passing any arguments tothreading.RLock()
is now deprecated. C version allows any numbers of args and kwargs, but they are just ignored. Python version does not allow any arguments. All arguments will be removed fromthreading.RLock()
in Python 3.15. (Contributed by Nikita Sobolev in gh-102029.)-
The undocumented keyword argument syntax for creating
NamedTuple
classes (NT = NamedTuple("NT", x=int)
) is deprecated, and will be disallowed in 3.15. Use the class-based syntax or the functional syntax instead.When using the functional syntax to create a
NamedTuple
class, failing to pass a value to the fields parameter (NT = NamedTuple("NT")
) is deprecated. PassingNone
to the fields parameter (NT = NamedTuple("NT", None)
) is also deprecated. Both will be disallowed in Python 3.15. To create aNamedTuple
class with 0 fields, useclass NT(NamedTuple): pass
orNT = NamedTuple("NT", [])
.
typing.TypedDict
: When using the functional syntax to create aTypedDict
class, failing to pass a value to the fields parameter (TD = TypedDict("TD")
) is deprecated. PassingNone
to the fields parameter (TD = TypedDict("TD", None)
) is also deprecated. Both will be disallowed in Python 3.15. To create aTypedDict
class with 0 fields, useclass TD(TypedDict): pass
orTD = TypedDict("TD", {})
.wave
: Deprecate thegetmark()
,setmark()
andgetmarkers()
methods of thewave.Wave_read
andwave.Wave_write
classes. They will be removed in Python 3.15. (Contributed by Victor Stinner in gh-105096.)
Pending Removal in Python 3.16¶
array
:array.array
'u'
type (wchar_t
): use the'w'
type instead (Py_UCS4
).symtable
: Deprecatesymtable.Class.get_methods()
due to the lack of interest. (Contributed by Bénédikt Tran in gh-119698.)
Pending Removal in Future Versions¶
The following APIs will be removed in the future, although there is currently no date scheduled for their removal.
argparse
: Nesting argument groups and nesting mutually exclusive groups are deprecated.-
~bool
, bitwise inversion on bool.bool(NotImplemented)
.Generators:
throw(type, exc, tb)
andathrow(type, exc, tb)
signature is deprecated: usethrow(exc)
andathrow(exc)
instead, the single argument signature.Currently Python accepts numeric literals immediately followed by keywords, for example
0in x
,1or x
,0if 1else 2
. It allows confusing and ambiguous expressions like[0x1for x in y]
(which can be interpreted as[0x1 for x in y]
or[0x1f or x in y]
). A syntax warning is raised if the numeric literal is immediately followed by one of keywordsand
,else
,for
,if
,in
,is
andor
. In a future release it will be changed to a syntax error. (gh-87999)Support for
__index__()
and__int__()
method returning non-int type: these methods will be required to return an instance of a strict subclass ofint
.Support for
__float__()
method returning a strict subclass offloat
: these methods will be required to return an instance offloat
.Support for
__complex__()
method returning a strict subclass ofcomplex
: these methods will be required to return an instance ofcomplex
.Delegation of
int()
to__trunc__()
method.Passing a complex number as the real or imag argument in the
complex()
constructor is now deprecated; it should only be passed as a single positional argument. (Contributed by Serhiy Storchaka in gh-109218.)
calendar
:calendar.January
andcalendar.February
constants are deprecated and replaced bycalendar.JANUARY
andcalendar.FEBRUARY
. (Contributed by Prince Roshan in gh-103636.)codeobject.co_lnotab
: use thecodeobject.co_lines()
method instead.-
utcnow()
: usedatetime.datetime.now(tz=datetime.UTC)
.utcfromtimestamp()
: usedatetime.datetime.fromtimestamp(timestamp, tz=datetime.UTC)
.
gettext
: Plural value must be an integer.-
load_module()
method: useexec_module()
instead.cache_from_source()
debug_override parameter is deprecated: use the optimization parameter instead.
-
EntryPoints
tuple interface.Implicit
None
on return values.
mailbox
: Use of StringIO input and text mode is deprecated, use BytesIO and binary mode instead.os
: Callingos.register_at_fork()
in multi-threaded process.pydoc.ErrorDuringImport
: A tuple value for exc_info parameter is deprecated, use an exception instance.re
: More strict rules are now applied 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. (Contributed by Serhiy Storchaka in gh-91760.)sre_compile
,sre_constants
andsre_parse
modules.shutil
:rmtree()
's onerror parameter is deprecated in Python 3.12; use the onexc parameter instead.ssl
options and protocols:ssl.SSLContext
without protocol argument is deprecated.ssl.SSLContext
:set_npn_protocols()
andselected_npn_protocol()
are deprecated: use ALPN instead.ssl.OP_NO_SSL*
optionsssl.OP_NO_TLS*
optionsssl.PROTOCOL_SSLv3
ssl.PROTOCOL_TLS
ssl.PROTOCOL_TLSv1
ssl.PROTOCOL_TLSv1_1
ssl.PROTOCOL_TLSv1_2
ssl.TLSVersion.SSLv3
ssl.TLSVersion.TLSv1
ssl.TLSVersion.TLSv1_1
sysconfig.is_python_build()
check_home parameter is deprecated and ignored.threading
methods:threading.Condition.notifyAll()
: usenotify_all()
.threading.Event.isSet()
: useis_set()
.threading.Thread.isDaemon()
,threading.Thread.setDaemon()
: usethreading.Thread.daemon
attribute.threading.Thread.getName()
,threading.Thread.setName()
: usethreading.Thread.name
attribute.threading.currentThread()
: usethreading.current_thread()
.threading.activeCount()
: usethreading.active_count()
.
unittest.IsolatedAsyncioTestCase
: it is deprecated to return a value that is notNone
from a test case.urllib.parse
deprecated functions:urlparse()
insteadsplitattr()
splithost()
splitnport()
splitpasswd()
splitport()
splitquery()
splittag()
splittype()
splituser()
splitvalue()
to_bytes()
urllib.request
:URLopener
andFancyURLopener
style of invoking requests is deprecated. Use newerurlopen()
functions and methods.wsgiref
:SimpleHandler.stdout.write()
should not do partial writes.xml.etree.ElementTree
: Testing the truth value of anElement
is deprecated. In a future release it will always returnTrue
. Prefer explicitlen(elem)
orelem is not None
tests instead.zipimport.zipimporter.load_module()
is deprecated: useexec_module()
instead.
CPython Bytecode Changes¶
The oparg of
YIELD_VALUE
is now1
if the yield is part of a yield-from or await, and0
otherwise. The oparg ofRESUME
was changed to add a bit indicating whether the except-depth is 1, which is needed to optimize closing of generators. (Contributed by Irit Katriel in gh-111354.)
C API Changes¶
New Features¶
You no longer have to define the
PY_SSIZE_T_CLEAN
macro before includingPython.h
when using#
formats in format codes. APIs accepting the format codes always usePy_ssize_t
for#
formats. (Contributed by Inada Naoki in gh-104922.)The keywords parameter of
PyArg_ParseTupleAndKeywords()
andPyArg_VaParseTupleAndKeywords()
now has type char *const* in C and const char *const* in C++, instead of char**. It makes these functions compatible with arguments of type const char *const*, const char** or char *const* in C++ and char *const* in C without an explicit type cast. This can be overridden with thePY_CXX_CONST
macro. (Contributed by Serhiy Storchaka in gh-65210.)Add
PyImport_AddModuleRef()
: similar toPyImport_AddModule()
, but return a strong reference instead of a borrowed reference. (Contributed by Victor Stinner in gh-105922.)Add
PyWeakref_GetRef()
function: similar toPyWeakref_GetObject()
but returns a strong reference, orNULL
if the referent is no longer live. (Contributed by Victor Stinner in gh-105927.)Add
PyObject_GetOptionalAttr()
andPyObject_GetOptionalAttrString()
, variants ofPyObject_GetAttr()
andPyObject_GetAttrString()
which don't raiseAttributeError
if the attribute is not found. These variants are more convenient and faster if the missing attribute should not be treated as a failure. (Contributed by Serhiy Storchaka in gh-106521.)Add
PyMapping_GetOptionalItem()
andPyMapping_GetOptionalItemString()
: variants ofPyObject_GetItem()
andPyMapping_GetItemString()
which don't raiseKeyError
if the key is not found. These variants are more convenient and faster if the missing key should not be treated as a failure. (Contributed by Serhiy Storchaka in gh-106307.)Add fixed variants of functions which silently ignore errors:
PyObject_HasAttrStringWithError()
replacesPyObject_HasAttrString()
.PyMapping_HasKeyStringWithError()
replacesPyMapping_HasKeyString()
.
New functions return not only
1
for true and0
for false, but also-1
for error.(Contributed by Serhiy Storchaka in gh-108511.)
If Python is built in debug mode or
with assertions
,PyTuple_SET_ITEM()
andPyList_SET_ITEM()
now check the index argument with an assertion. (Contributed by Victor Stinner in gh-106168.)Add
PyModule_Add()
function: similar toPyModule_AddObjectRef()
andPyModule_AddObject()
but always steals a reference to the value. (Contributed by Serhiy Storchaka in gh-86493.)Add
PyDict_GetItemRef()
andPyDict_GetItemStringRef()
functions: similar toPyDict_GetItemWithError()
but returning a strong reference instead of a borrowed reference. Moreover, these functions return -1 on error and so checkingPyErr_Occurred()
is not needed. (Contributed by Victor Stinner in gh-106004.)Added
PyDict_SetDefaultRef()
, which is similar toPyDict_SetDefault()
but returns a strong reference instead of a borrowed reference. This function returns-1
on error,0
on insertion, and1
if the key was already present in the dictionary. (Contributed by Sam Gross in gh-112066.)Add
PyDict_ContainsString()
function: same asPyDict_Contains()
, but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*. (Contributed by Victor Stinner in gh-108314.)Added
PyList_GetItemRef()
function: similar toPyList_GetItem()
but returns a strong reference instead of a borrowed reference.Add
Py_IsFinalizing()
function: check if the main Python interpreter is shutting down. (Contributed by Victor Stinner in gh-108014.)Add
PyLong_AsInt()
function: similar toPyLong_AsLong()
, but store the result in a C int instead of a C long. Previously, it was known as the private function_PyLong_AsInt()
(with an underscore prefix). (Contributed by Victor Stinner in gh-108014.)Python built with
configure
--with-trace-refs
(tracing references) now supports the Limited API. (Contributed by Victor Stinner in gh-108634.)Add
PyObject_VisitManagedDict()
andPyObject_ClearManagedDict()
functions which must be called by the traverse and clear functions of a type usingPy_TPFLAGS_MANAGED_DICT
flag. The pythoncapi-compat project can be used to get these functions on Python 3.11 and 3.12. (Contributed by Victor Stinner in gh-107073.)Add
PyUnicode_EqualToUTF8AndSize()
andPyUnicode_EqualToUTF8()
functions: compare Unicode object with a const char* UTF-8 encoded string and return true (1
) if they are equal, or false (0
) otherwise. These functions do not raise exceptions. (Contributed by Serhiy Storchaka in gh-110289.)Add
PyThreadState_GetUnchecked()
function: similar toPyThreadState_Get()
, but don't kill the process with a fatal error if it is NULL. The caller is responsible to check if the result is NULL. Previously, the function was private and known as_PyThreadState_UncheckedGet()
. (Contributed by Victor Stinner in gh-108867.)Add
PySys_AuditTuple()
function: similar toPySys_Audit()
, but pass event arguments as a Pythontuple
object. (Contributed by Victor Stinner in gh-85283.)PyArg_ParseTupleAndKeywords()
now supports non-ASCII keyword parameter names. (Contributed by Serhiy Storchaka in gh-110815.)Add
PyMem_RawMalloc()
,PyMem_RawCalloc()
,PyMem_RawRealloc()
andPyMem_RawFree()
to the limited C API (version 3.13). (Contributed by Victor Stinner in gh-85283.)Add
PySys_Audit()
andPySys_AuditTuple()
functions to the limited C API. (Contributed by Victor Stinner in gh-85283.)Add
PyErr_FormatUnraisable()
function: similar toPyErr_WriteUnraisable()
, but allow customizing the warning message. (Contributed by Serhiy Storchaka in gh-108082.)Add
PyList_Extend()
andPyList_Clear()
functions: similar to Pythonlist.extend()
andlist.clear()
methods. (Contributed by Victor Stinner in gh-111138.)Add
PyDict_Pop()
andPyDict_PopString()
functions: remove a key from a dictionary and optionally return the removed value. This is similar todict.pop()
, but without the default value and not raisingKeyError
if the key is missing. (Contributed by Stefan Behnel and Victor Stinner in gh-111262.)Add
Py_HashPointer()
function to hash a pointer. (Contributed by Victor Stinner in gh-111545.)Add
PyObject_GenericHash()
function that implements the default hashing function of a Python object. (Contributed by Serhiy Storchaka in gh-113024.)Add PyTime C API:
PyTime_t
type.PyTime_MIN
andPyTime_MAX
constants.Add functions:
(Contributed by Victor Stinner and Petr Viktorin in gh-110850.)
Add
PyLong_AsNativeBytes()
,PyLong_FromNativeBytes()
andPyLong_FromUnsignedNativeBytes()
functions to simplify converting between native integer types and Pythonint
objects. (Contributed by Steve Dower in gh-111140.)Add
PyType_GetFullyQualifiedName()
function to get the type's fully qualified name. Equivalent tof"{type.__module__}.{type.__qualname__}"
, ortype.__qualname__
iftype.__module__
is not a string or is equal to"builtins"
. (Contributed by Victor Stinner in gh-111696.)Add
PyType_GetModuleName()
function to get the type's module name. Equivalent to getting thetype.__module__
attribute. (Contributed by Eric Snow and Victor Stinner in gh-111696.)Add support for
%T
,%#T
,%N
and%#N
formats toPyUnicode_FromFormat()
: format the fully qualified name of an object type and of a type: callPyType_GetModuleName()
. See PEP 737 for more information. (Contributed by Victor Stinner in gh-111696.)Add
Py_GetConstant()
andPy_GetConstantBorrowed()
functions to get constants. For example,Py_GetConstant(Py_CONSTANT_ZERO)
returns a strong reference to the constant zero. (Contributed by Victor Stinner in gh-115754.)Add
PyType_GetModuleByDef()
to the limited C API (Contributed by Victor Stinner in gh-116936.)Add two new functions to the C-API,
PyRefTracer_SetTracer()
andPyRefTracer_GetTracer()
, that allows to track object creation and destruction the same way thetracemalloc
module does. (Contributed by Pablo Galindo in gh-93502.)Add
PyEval_GetFrameBuiltins()
,PyEval_GetFrameGlobals()
, andPyEval_GetFrameLocals()
to the C API. These replacements forPyEval_GetBuiltins()
,PyEval_GetGlobals()
, andPyEval_GetLocals()
return strong references rather than borrowed references. (Added as part of PEP 667.)Add
PyMutex
API, a lightweight mutex that occupies a single byte. ThePyMutex_Lock()
function will release the GIL (if currently held) if the operation needs to block. (Contributed by Sam Gross in gh-108724.)
Build Changes¶
The
configure
option--with-system-libmpdec
now defaults toyes
. The bundled copy oflibmpdecimal
will be removed in Python 3.15.Autoconf 2.71 and aclocal 1.16.4 are now required to regenerate the
configure
script. (Contributed by Christian Heimes in gh-89886.)SQLite 3.15.2 or newer is required to build the
sqlite3
extension module. (Contributed by Erlend Aasland in gh-105875.)Python built with
configure
--with-trace-refs
(tracing references) is now ABI compatible with the Python release build and debug build. (Contributed by Victor Stinner in gh-108634.)Building CPython now requires a compiler with support for the C11 atomic library, GCC built-in atomic functions, or MSVC interlocked intrinsics.
The
errno
,fcntl
,grp
,md5
,pwd
,resource
,termios
,winsound
,_ctypes_test
,_multiprocessing.posixshmem
,_scproxy
,_stat
,_statistics
,_testconsole
,_testimportmultiple
and_uuid
C extensions are now built with the limited C API. (Contributed by Victor Stinner in gh-85283.)wasm32-wasi
is now a PEP 11 tier 2 platform. (Contributed by Brett Cannon in gh-115192.)wasm32-emscripten
is no longer a PEP 11 supported platform. (Contributed by Brett Cannon in gh-115192.)Python now bundles the mimalloc library. It is licensed under the MIT license; see mimalloc license. The bundled mimalloc has custom changes, see gh-113141 for details. (Contributed by Dino Viehland in gh-109914.)
On POSIX systems, the pkg-config (
.pc
) filenames now include the ABI flags. For example, the free-threaded build generatespython-3.13t.pc
and the debug build generatespython-3.13d.pc
.
Porting to Python 3.13¶
This section lists previously described changes and other bugfixes that may require changes to your code.
Changes in the Python API¶
An
OSError
is now raised bygetpass.getuser()
for any failure to retrieve a username, instead ofImportError
on non-Unix platforms orKeyError
on Unix platforms where the password database is empty.The
threading
module now expects the_thread
module to have an_is_main_interpreter
attribute. It is a function with no arguments that returnsTrue
if the current interpreter is the main interpreter.Any library or application that provides a custom
_thread
module must provide_is_main_interpreter()
, just like the module's other "private" attributes. (See gh-112826.)mailbox.Maildir
now ignores files with a leading dot. (Contributed by Zackery Spytz in gh-65559.)pathlib.Path.glob()
andrglob()
now return both files and directories if a pattern that ends with "**
" is given, rather than directories only. Users may add a trailing slash to match only directories.The value of the
mode
attribute ofgzip.GzipFile
was changed from integer (1
or2
) to string ('rb'
or'wb'
). The value of themode
attribute of the readable file-like object returned byzipfile.ZipFile.open()
was changed from'r'
to'rb'
. (Contributed by Serhiy Storchaka in gh-115961.)functools.partial
now emits aFutureWarning
when it is used as a method. Its behavior will be changed in future Python versions. Wrap it instaticmethod()
if you want to preserve the old behavior. (Contributed by Serhiy Storchaka in gh-121027.)
Calling
locals()
in an optimized scope now produces an independent snapshot on each call, and hence no longer implicitly updates previously returned references. Obtaining the legacy CPython behaviour now requires explicit calls to update the initially returned dictionary with the results of subsequent calls tolocals()
. Code execution functions that implicitly targetlocals()
(such asexec
andeval
) must be passed an explicit namespace to access their results in an optimized scope. (Changed as part of PEP 667.)Calling
locals()
from a comprehension at module or class scope (including viaexec
oreval
) once more behaves as if the comprehension were running as an independent nested function (i.e. the local variables from the containing scope are not included). In Python 3.12, this had changed to include the local variables from the containing scope when implementing PEP 709. (Changed as part of PEP 667.)Accessing
FrameType.f_locals
in an optimized scope now returns a write-through proxy rather than a snapshot that gets updated at ill-specified times. If a snapshot is desired, it must be created explicitly withdict
or the proxy's.copy()
method. (Changed as part of PEP 667.)
Changes in the C API¶
Python.h
no longer includes the<ieeefp.h>
standard header. It was included for thefinite()
function which is now provided by the<math.h>
header. It should now be included explicitly if needed. Remove also theHAVE_IEEEFP_H
macro. (Contributed by Victor Stinner in gh-108765.)Python.h
no longer includes these standard header files:<time.h>
,<sys/select.h>
and<sys/time.h>
. If needed, they should now be included explicitly. For example,<time.h>
provides theclock()
andgmtime()
functions,<sys/select.h>
provides theselect()
function, and<sys/time.h>
provides thefutimes()
,gettimeofday()
andsetitimer()
functions. (Contributed by Victor Stinner in gh-108765.)On Windows,
Python.h
no longer includes the<stddef.h>
standard header file. If needed, it should now be included explicitly. For example, it providesoffsetof()
function, andsize_t
andptrdiff_t
types. Including<stddef.h>
explicitly was already needed by all other platforms, theHAVE_STDDEF_H
macro is only defined on Windows. (Contributed by Victor Stinner in gh-108765.)If the
Py_LIMITED_API
macro is defined,Py_BUILD_CORE
,Py_BUILD_CORE_BUILTIN
andPy_BUILD_CORE_MODULE
macros are now undefined by<Python.h>
. (Contributed by Victor Stinner in gh-85283.)The old trashcan macros
Py_TRASHCAN_SAFE_BEGIN
andPy_TRASHCAN_SAFE_END
were removed. They should be replaced by the new macrosPy_TRASHCAN_BEGIN
andPy_TRASHCAN_END
.A
tp_dealloc
function that has the old macros, such as:static void mytype_dealloc(mytype *p) { PyObject_GC_UnTrack(p); Py_TRASHCAN_SAFE_BEGIN(p); ... Py_TRASHCAN_SAFE_END }
should migrate to the new macros as follows:
static void mytype_dealloc(mytype *p) { PyObject_GC_UnTrack(p); Py_TRASHCAN_BEGIN(p, mytype_dealloc) ... Py_TRASHCAN_END }
Note that
Py_TRASHCAN_BEGIN
has a second argument which should be the deallocation function it is in. The new macros were added in Python 3.8 and the old macros were deprecated in Python 3.11. (Contributed by Irit Katriel in gh-105111.)Functions
PyDict_GetItem()
,PyDict_GetItemString()
,PyMapping_HasKey()
,PyMapping_HasKeyString()
,PyObject_HasAttr()
,PyObject_HasAttrString()
, andPySys_GetObject()
, which clear all errors which occurred when calling them, now report them usingsys.unraisablehook()
. You may replace them with other functions as recommended in the documentation. (Contributed by Serhiy Storchaka in gh-106672.)PyCode_GetFirstFree()
is an unstable API now and has been renamed toPyUnstable_Code_GetFirstFree()
. (Contributed by Bogdan Romanyuk in gh-115781.)
The effects of mutating the dictionary returned from
PyEval_GetLocals()
in an optimized scope have changed. New dict entries added this way will now only be visible to subsequentPyEval_GetLocals()
calls in that frame, asPyFrame_GetLocals()
,locals()
, andFrameType.f_locals
no longer access the same underlying cached dictionary. Changes made to entries for actual variable names and names added via the write-through proxy interfaces will be overwritten on subsequent calls toPyEval_GetLocals()
in that frame. The recommended code update depends on how the function was being used, so refer to the deprecation notice on the function for details. (Changed as part of PEP 667.)Calling
PyFrame_GetLocals()
in an optimized scope now returns a write-through proxy rather than a snapshot that gets updated at ill-specified times. If a snapshot is desired, it must be created explicitly (e.g. withPyDict_Copy()
) or by calling the newPyEval_GetFrameLocals()
API. (Changed as part of PEP 667.)PyFrame_FastToLocals()
andPyFrame_FastToLocalsWithError()
no longer have any effect. Calling these functions has been redundant since Python 3.11, whenPyFrame_GetLocals()
was first introduced. (Changed as part of PEP 667.)PyFrame_LocalsToFast()
no longer has any effect. Calling this function is redundant now thatPyFrame_GetLocals()
returns a write-through proxy for optimized scopes. (Changed as part of PEP 667.)
Removed C APIs¶
Remove many APIs (functions, macros, variables) with names prefixed by
_Py
or_PY
(considered as private API). If your project is affected by one of these removals and you consider that the removed API should remain available, please open a new issue to request a public C API and addcc @vstinner
to the issue to notify Victor Stinner. (Contributed by Victor Stinner in gh-106320.)Remove functions deprecated in Python 3.9:
PyEval_CallObject()
,PyEval_CallObjectWithKeywords()
: usePyObject_CallNoArgs()
orPyObject_Call()
instead. Warning:PyObject_Call()
positional arguments must be atuple
and must not beNULL
, keyword arguments must be adict
orNULL
, whereas removed functions checked arguments type and acceptedNULL
positional and keyword arguments. To replacePyEval_CallObjectWithKeywords(func, NULL, kwargs)
withPyObject_Call()
, pass an empty tuple as positional arguments usingPyTuple_New(0)
.PyEval_CallFunction()
: usePyObject_CallFunction()
instead.PyEval_CallMethod()
: usePyObject_CallMethod()
instead.PyCFunction_Call()
: usePyObject_Call()
instead.
(Contributed by Victor Stinner in gh-105107.)
Remove old buffer protocols deprecated in Python 3.0. Use Protocole tampon instead.
PyObject_CheckReadBuffer()
: UsePyObject_CheckBuffer()
to test if the object supports the buffer protocol. Note thatPyObject_CheckBuffer()
doesn't guarantee thatPyObject_GetBuffer()
will succeed. To test if the object is actually readable, see the next example ofPyObject_GetBuffer()
.PyObject_AsCharBuffer()
,PyObject_AsReadBuffer()
:PyObject_GetBuffer()
andPyBuffer_Release()
instead:Py_buffer view; if (PyObject_GetBuffer(obj, &view, PyBUF_SIMPLE) < 0) { return NULL; } // Use `view.buf` and `view.len` to read from the buffer. // You may need to cast buf as `(const char*)view.buf`. PyBuffer_Release(&view);
PyObject_AsWriteBuffer()
: UsePyObject_GetBuffer()
andPyBuffer_Release()
instead:Py_buffer view; if (PyObject_GetBuffer(obj, &view, PyBUF_WRITABLE) < 0) { return NULL; } // Use `view.buf` and `view.len` to write to the buffer. PyBuffer_Release(&view);
(Contributed by Inada Naoki in gh-85275.)
Remove the following old functions to configure the Python initialization, deprecated in Python 3.11:
PySys_AddWarnOptionUnicode()
: usePyConfig.warnoptions
instead.PySys_AddWarnOption()
: usePyConfig.warnoptions
instead.PySys_AddXOption()
: usePyConfig.xoptions
instead.PySys_HasWarnOptions()
: usePyConfig.xoptions
instead.PySys_SetPath()
: setPyConfig.module_search_paths
instead.Py_SetPath()
: setPyConfig.module_search_paths
instead.Py_SetStandardStreamEncoding()
: setPyConfig.stdio_encoding
instead, and set also maybePyConfig.legacy_windows_stdio
(on Windows)._Py_SetProgramFullPath()
: setPyConfig.executable
instead.
Use the new
PyConfig
API of the Python Initialization Configuration instead (PEP 587), added to Python 3.8. (Contributed by Victor Stinner in gh-105145.)Remove
PyEval_ThreadsInitialized()
function, deprecated in Python 3.9. Since Python 3.7,Py_Initialize()
always creates the GIL: callingPyEval_InitThreads()
does nothing andPyEval_ThreadsInitialized()
always returned non-zero. (Contributed by Victor Stinner in gh-105182.)Remove
PyEval_AcquireLock()
andPyEval_ReleaseLock()
functions, deprecated in Python 3.2. They didn't update the current thread state. They can be replaced with:low-level
PyEval_AcquireThread()
andPyEval_RestoreThread()
;
(Contributed by Victor Stinner in gh-105182.)
Remove private
_PyObject_FastCall()
function: usePyObject_Vectorcall()
which is available since Python 3.8 (PEP 590). (Contributed by Victor Stinner in gh-106023.)Remove
cpython/pytime.h
header file: it only contained private functions. (Contributed by Victor Stinner in gh-106316.)Remove
_PyInterpreterState_Get()
alias toPyInterpreterState_Get()
which was kept for backward compatibility with Python 3.8. The pythoncapi-compat project can be used to getPyInterpreterState_Get()
on Python 3.8 and older. (Contributed by Victor Stinner in gh-106320.)The
PyModule_AddObject()
function is now soft deprecated:PyModule_Add()
orPyModule_AddObjectRef()
functions should be used instead. (Contributed by Serhiy Storchaka in gh-86493.)Remove undocumented
PY_TIMEOUT_MAX
constant from the limited C API. (Contributed by Victor Stinner in gh-110014.)
Deprecated C APIs¶
Deprecate the old
Py_UNICODE
andPY_UNICODE_TYPE
types: use directly thewchar_t
type instead. Since Python 3.3,Py_UNICODE
andPY_UNICODE_TYPE
are just aliases towchar_t
. (Contributed by Victor Stinner in gh-105156.)Deprecate old Python initialization functions:
PySys_ResetWarnOptions()
: clearsys.warnoptions
andwarnings.filters
instead.Py_GetExecPrefix()
: getsys.exec_prefix
instead.Py_GetPath()
: getsys.path
instead.Py_GetPrefix()
: getsys.prefix
instead.Py_GetProgramFullPath()
: getsys.executable
instead.Py_GetProgramName()
: getsys.executable
instead.Py_GetPythonHome()
: getPyConfig.home
orPYTHONHOME
environment variable instead.
Functions scheduled for removal in Python 3.15. (Contributed by Victor Stinner in gh-105145.)
Deprecate the
PyImport_ImportModuleNoBlock()
function which is just an alias toPyImport_ImportModule()
since Python 3.3. Scheduled for removal in Python 3.15. (Contributed by Victor Stinner in gh-105396.)Deprecate the
PyWeakref_GetObject()
andPyWeakref_GET_OBJECT()
functions, which return a borrowed reference: use the newPyWeakref_GetRef()
function instead, it returns a strong reference. The pythoncapi-compat project can be used to getPyWeakref_GetRef()
on Python 3.12 and older. (Contributed by Victor Stinner in gh-105927.)Deprecate the
PyEval_GetBuiltins()
,PyEval_GetGlobals()
, andPyEval_GetLocals()
functions, which return a borrowed reference. Refer to the deprecation notices on each function for their recommended replacements. (Soft deprecated as part of PEP 667.)
Pending Removal in Python 3.14¶
The
ma_version_tag
field inPyDictObject
for extension modules (PEP 699; gh-101193).Creating
immutable types
with mutable bases (gh-95388).Functions to configure Python's initialization, deprecated in Python 3.11:
PySys_SetArgvEx()
: setPyConfig.argv
instead.PySys_SetArgv()
: setPyConfig.argv
instead.Py_SetProgramName()
: setPyConfig.program_name
instead.Py_SetPythonHome()
: setPyConfig.home
instead.
The
Py_InitializeFromConfig()
API should be used withPyConfig
instead.Global configuration variables:
Py_DebugFlag
: usePyConfig.parser_debug
instead.Py_VerboseFlag
: usePyConfig.verbose
instead.Py_QuietFlag
: usePyConfig.quiet
instead.Py_InteractiveFlag
: usePyConfig.interactive
instead.Py_InspectFlag
: usePyConfig.inspect
instead.Py_OptimizeFlag
: usePyConfig.optimization_level
instead.Py_NoSiteFlag
: usePyConfig.site_import
instead.Py_BytesWarningFlag
: usePyConfig.bytes_warning
instead.Py_FrozenFlag
: usePyConfig.pathconfig_warnings
instead.Py_IgnoreEnvironmentFlag
: usePyConfig.use_environment
instead.Py_DontWriteBytecodeFlag
: usePyConfig.write_bytecode
instead.Py_NoUserSiteDirectory
: usePyConfig.user_site_directory
instead.Py_UnbufferedStdioFlag
: usePyConfig.buffered_stdio
instead.Py_HashRandomizationFlag
: usePyConfig.use_hash_seed
andPyConfig.hash_seed
instead.Py_IsolatedFlag
: usePyConfig.isolated
instead.Py_LegacyWindowsFSEncodingFlag
: usePyPreConfig.legacy_windows_fs_encoding
instead.Py_LegacyWindowsStdioFlag
: usePyConfig.legacy_windows_stdio
instead.Py_FileSystemDefaultEncoding
: usePyConfig.filesystem_encoding
instead.Py_HasFileSystemDefaultEncoding
: usePyConfig.filesystem_encoding
instead.Py_FileSystemDefaultEncodeErrors
: usePyConfig.filesystem_errors
instead.Py_UTF8Mode
: usePyPreConfig.utf8_mode
instead. (seePy_PreInitialize()
)
The
Py_InitializeFromConfig()
API should be used withPyConfig
instead.
Pending Removal in Python 3.15¶
The bundled copy of
libmpdecimal
.PyImport_ImportModuleNoBlock()
: usePyImport_ImportModule()
instead.PyWeakref_GET_OBJECT()
: usePyWeakref_GetRef()
instead.PyWeakref_GetObject()
: usePyWeakref_GetRef()
instead.Py_UNICODE_WIDE
type: usewchar_t
instead.Py_UNICODE
type: usewchar_t
instead.Python initialization functions:
PySys_ResetWarnOptions()
: clearsys.warnoptions
andwarnings.filters
instead.Py_GetExecPrefix()
: getsys.exec_prefix
instead.Py_GetPath()
: getsys.path
instead.Py_GetPrefix()
: getsys.prefix
instead.Py_GetProgramFullPath()
: getsys.executable
instead.Py_GetProgramName()
: getsys.executable
instead.Py_GetPythonHome()
: getPyConfig.home
or thePYTHONHOME
environment variable instead.
Pending Removal in Future Versions¶
The following APIs are deprecated and will be removed, although there is currently no date scheduled for their removal.
Py_TPFLAGS_HAVE_FINALIZE
: unneeded since Python 3.8.PyErr_Fetch()
: usePyErr_GetRaisedException()
instead.PyErr_NormalizeException()
: usePyErr_GetRaisedException()
instead.PyErr_Restore()
: usePyErr_SetRaisedException()
instead.PyModule_GetFilename()
: usePyModule_GetFilenameObject()
instead.PyOS_AfterFork()
: usePyOS_AfterFork_Child()
instead.PySlice_GetIndicesEx()
: usePySlice_Unpack()
andPySlice_AdjustIndices()
instead.PyUnicode_AsDecodedObject()
: usePyCodec_Decode()
instead.PyUnicode_AsDecodedUnicode()
: usePyCodec_Decode()
instead.PyUnicode_AsEncodedObject()
: usePyCodec_Encode()
instead.PyUnicode_AsEncodedUnicode()
: usePyCodec_Encode()
instead.PyUnicode_READY()
: unneeded since Python 3.12PyErr_Display()
: usePyErr_DisplayException()
instead._PyErr_ChainExceptions()
: use_PyErr_ChainExceptions1
instead.PyBytesObject.ob_shash
member: callPyObject_Hash()
instead.PyDictObject.ma_version_tag
member.Thread Local Storage (TLS) API:
PyThread_create_key()
: usePyThread_tss_alloc()
instead.PyThread_delete_key()
: usePyThread_tss_free()
instead.PyThread_set_key_value()
: usePyThread_tss_set()
instead.PyThread_get_key_value()
: usePyThread_tss_get()
instead.PyThread_delete_key_value()
: usePyThread_tss_delete()
instead.PyThread_ReInitTLS()
: unneeded since Python 3.7.
Regression Test Changes¶
Python built with
configure
--with-pydebug
now supports a-X presite=package.module
command-line option. If used, it specifies a module that should be imported early in the lifecycle of the interpreter, beforesite.py
is executed. (Contributed by Łukasz Langa in gh-110769.)