What's New In Python 3.13¶
- Editor:
TBD
This article explains the new features in Python 3.13, compared to 3.12.
For full details, see the changelog.
备注
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¶
Important deprecations, removals or restrictions:
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,uuandxdrlib.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¶
Other Language Changes¶
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.
.pycfile). For example, cache file size forsqlalchemy.orm.sessionin 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_ASTexcept that the returnedASTis optimized according to the value of theoptimizeargument. (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
globaldeclaration in anexceptblock is rejected when the global is used in theelseblock. (Contributed by Irit Katriel in gh-111123.)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_modulescommand-line option. (Contributed by Yilei Yang in gh-111374.)
New Modules¶
None yet.
Improved Modules¶
ast¶
ast.parse()now accepts an optional argumentoptimizewhich is passed on to thecompile()built-in. This makes it possible to obtain an optimizedAST. (Contributed by Irit Katriel in gh-108113).
array¶
Add
'w'type code (Py_UCS4) that can be used for Unicode strings. It can be used instead of'u'type code, which is deprecated. (Contributed by Inada Naoki in gh-80480.)
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.)
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(),dataclassinstances, variousdatetimeobjects,Signatureobjects,Parameterobjects, code object, and any user classes which define the__replace__()method. (Contributed by Serhiy Storchaka in gh-108751.)
dis¶
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.)
doctest¶
The
doctest.DocTestRunner.run()method now counts the number of skipped tests. Adddoctest.DocTestRunner.skipsanddoctest.TestResults.skippedattributes. (Contributed by Victor Stinner in gh-108794.)
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.)
io¶
The io.IOBase finalizer now logs the close() method errors with
sys.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_mappedproperty, which returns the IPv4-mapped IPv6 address. (Contributed by Charles Machalow in gh-109466.)
mmap¶
The
mmap.mmapclass now has anseekable()method that can be used where it requires a file-like object with seekable and theseek()method return the new absolute position. (Contributed by Donghee Na and Sylvie Liberman in gh-111835.)
opcode¶
Move
opcode.ENABLE_SPECIALIZATIONto_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_OPCODEandopcode.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_COUNTor 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)
pathlib¶
Add
pathlib.UnsupportedOperation, which is raised instead ofNotImplementedErrorwhen a path operation isn't supported. (Contributed by Barney Gale in gh-89812.)Add
pathlib.Path.from_uri(), a new constructor to create apathlib.Pathobject from a 'file' URI (file:/). (Contributed by Barney Gale in gh-107465.)Add support for recursive wildcards in
pathlib.PurePath.match(). (Contributed by Barney Gale in gh-73435.)Add follow_symlinks keyword-only argument to
pathlib.Path.glob(),rglob(),is_file(), andis_dir(). (Contributed by Barney Gale in gh-77609 and gh-105793.)
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_pathis set (via the-Pcommand line option orPYTHONSAFEPATHenvironment variable). (Contributed by Tian Gao and Christian Walther in gh-111762.)
sqlite3¶
A
ResourceWarningis now emitted if asqlite3.Connectionobject is notclosedexplicitly. (Contributed by Erlend E. Aasland in gh-105539.)
tkinter¶
Add
tkinterwidget 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.)Add support of the "vsapi" element type in the
element_create()method oftkinter.ttk.Style. (Contributed by Serhiy Storchaka in gh-68166.)
traceback¶
Add show_group parameter to
traceback.TracebackException.format_exception_only()to format the nested exceptions of aBaseExceptionGroupinstance, 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_typeshould be saved. (Contributed by Irit Katriel in gh-112332.)
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.)
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.EnvBuilderandvenv.create()), and opt-out via the CLI (using--without-scm-ignore-files). (Contributed by Brett Cannon in gh-108125.)
Optimizations¶
textwrap.indent()is now ~30% faster than before for large input. (Contributed by Inada Naoki in gh-107369.)
Deprecated¶
array:array's'u'format code, deprecated in docs since Python 3.3, emitsDeprecationWarningsince 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()andctypes.ARRAY()functions. Replacectypes.ARRAY(item_type, size)withitem_type * size. (Contributed by Victor Stinner in gh-105733.)getoptandoptparsemodules: They are now soft deprecated: theargparseshould be used for new projects. Previously, theoptparsemodule 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.)http.server:http.server.CGIHTTPRequestHandlernow emits aDeprecationWarningas 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--cgiflag to thepython -m http.servercommand line in 3.15.-
The field exc_type of
traceback.TracebackExceptionis deprecated. Use exc_type_str instead.
-
Creating a
typing.NamedTupleclass 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.NamedTupleclass or atyping.TypedDictclass, failing to pass a value to the 'fields' parameter (NT = NamedTuple("NT")orTD = TypedDict("TD")) is deprecated. PassingNoneto 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): passorNT = NamedTuple("NT", []). To create a TypedDict class with 0 fields, useclass TD(TypedDict): passorTD = 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 thetypingmodule, it has yet to be supported by any major type checkers. (Contributed by Alex Waygood in gh-106309.)typing.AnyStris deprecated. In Python 3.16, it will be removed fromtyping.__all__, and aDeprecationWarningwill 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.)
wave: Deprecate thegetmark(),setmark()andgetmarkers()methods of thewave.Wave_readandwave.Wave_writeclasses. They will be removed in Python 3.15. (Contributed by Victor Stinner in gh-105096.)Passing more than one positional argument to
sqlite3.connect()and thesqlite3.Connectionconstructor 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.ConnectionAPIs:Deprecate passing the callback callable by keyword for the following
sqlite3.ConnectionAPIs:The affected parameters will become positional-only in Python 3.15.
(Contributed by Erlend E. Aasland in gh-107948 and gh-108278.)
The
dis.HAVE_ARGUMENTseparator is deprecated. Check membership inhasarginstead. (Contributed by Irit Katriel in gh-109319.)Deprecate non-standard format specifier "N" for
decimal.Decimal. It was not documented and only supported in the C implementation. (Contributed by Serhiy Storchaka in gh-89902.)Emit deprecation warning for non-integer numbers in
gettextfunctions and methods that consider plural forms even if the translation was not found. (Contributed by Serhiy Storchaka in gh-88434.)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.)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.)
Pending Removal in Python 3.14¶
argparse: The type, choices, and metavar parameters ofargparse.BooleanOptionalActionare 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 aDeprecationWarningto be emitted at runtime when they are accessed or used, and will be removed in Python 3.14:ast.Numast.Strast.Bytesast.NameConstantast.Ellipsis
Use
ast.Constantinstead. (Contributed by Serhiy Storchaka in gh-90953.)collections.abc: DeprecatedByteString. PreferSequenceorBuffer. 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.abcdeprecated classes:importlib.abc.ResourceReaderimportlib.abc.Traversableimportlib.abc.TraversableResources
Use
importlib.resources.abcclasses instead:(Contributed by Jason R. Coombs and Hugo van Kemenade in gh-93963.)
itertoolshad 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 上下文和启动方法.pathlib:is_relative_to(),relative_to(): passing additional arguments is deprecated.pkgutil.find_loader()andpkgutil.get_loader()now raiseDeprecationWarning; useimportlib.util.find_spec()instead. (Contributed by Nikita Sobolev in gh-97850.)pty:master_open(): usepty.openpty().slave_open(): usepty.openpty().
shutil.rmtree()onerror parameter is deprecated in 3.12, and will be removed in 3.14: use the onexc parameter instead.-
versionandversion_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
sqlite3documentation for suggested replacement recipes.
types.CodeType: Accessingco_lnotabwas deprecated in PEP 626 since 3.10 and was planned to be removed in 3.12, but it only got a properDeprecationWarningin 3.12. May be removed in 3.14. (Contributed by Nikita Sobolev in gh-101866.)typing:ByteString, deprecated since Python 3.9, now causes aDeprecationWarningto be emitted when it is used.urllib.parse.Quoteris deprecated: it was not intended to be a public API. (Contributed by Gregory P. Smith in gh-88168.)xml.etree.ElementTree: Testing the truth value of anElementis deprecated and will raise an exception in Python 3.14.
Pending Removal in Python 3.15¶
http.server.CGIHTTPRequestHandlerwill be removed along with its related--cgiflag 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.)-
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. PassingNoneto the 'fields' parameter (NT = NamedTuple("NT", None)) is also deprecated. Both will be disallowed in Python 3.15. To create a NamedTuple class with 0 fields, useclass NT(NamedTuple): passorNT = NamedTuple("NT", []).
typing.TypedDict: When using the functional syntax to create a TypedDict class, failing to pass a value to the 'fields' parameter (TD = TypedDict("TD")) is deprecated. PassingNoneto the 'fields' parameter (TD = TypedDict("TD", None)) is also deprecated. Both will be disallowed in Python 3.15. To create a TypedDict class with 0 fields, useclass TD(TypedDict): passorTD = TypedDict("TD", {}).wave: Deprecate thegetmark(),setmark()andgetmarkers()methods of thewave.Wave_readandwave.Wave_writeclasses. They will be removed in Python 3.15. (Contributed by Victor Stinner in gh-105096.)Passing any arguments to
threading.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.)
Pending Removal in Python 3.16¶
array.array'u'type (wchar_t): use the'w'type instead (Py_UCS4).
Pending Removal in Future Versions¶
The following APIs were deprecated in earlier Python versions and will be removed, 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,isandor. 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.
calendar:calendar.Januaryandcalendar.Februaryconstants are deprecated and replaced bycalendar.JANUARYandcalendar.FEBRUARY. (Contributed by Prince Roshan in gh-103636.)-
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.
-
EntryPointstuple interface.Implicit
Noneon 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.)ssloptions and protocols:ssl.SSLContextwithout protocol argument is deprecated.ssl.SSLContext:set_npn_protocols()and~ssl.SSLContext.selected_npn_protocol()are deprecated: use ALPN instead.ssl.OP_NO_SSL*optionsssl.OP_NO_TLS*optionsssl.PROTOCOL_SSLv3ssl.PROTOCOL_TLSssl.PROTOCOL_TLSv1ssl.PROTOCOL_TLSv1_1ssl.PROTOCOL_TLSv1_2ssl.TLSVersion.SSLv3ssl.TLSVersion.TLSv1ssl.TLSVersion.TLSv1_1
sre_compile,sre_constantsandsre_parsemodules.types.CodeType.co_lnotab: use theco_linesattribute instead.sysconfig.is_python_build()check_home parameter is deprecated and ignored.threadingmethods:threading.Condition.notifyAll(): usenotify_all().threading.Event.isSet(): useis_set().threading.Thread.isDaemon(),threading.Thread.setDaemon(): usethreading.Thread.daemonattribute.threading.Thread.getName(),threading.Thread.setName(): usethreading.Thread.nameattribute.threading.currentThread(): usethreading.current_thread().threading.activeCount(): usethreading.active_count().
unittest.IsolatedAsyncioTestCase: it is deprecated to return a value that is not None from a test case.urllib.request:URLopenerandFancyURLopenerstyle of invoking requests is deprecated. Use newerurlopen()functions and methods.urllib.parse.to_bytes().urllib.parsedeprecated functions:urlparse()insteadsplitattr()splithost()splitnport()splitpasswd()splitport()splitquery()splittag()splittype()splituser()splitvalue()
wsgiref:SimpleHandler.stdout.write()should not do partial writes.zipimport.zipimporter.load_module()is deprecated: useexec_module()instead.
Removed¶
PEP 594: dead batteries¶
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.)cgiandcgitb.cgi.FieldStoragecan typically be replaced withurllib.parse.parse_qsl()forGETandHEADrequests, and theemail.messagemodule or multipart PyPI project forPOSTandPUT.cgi.parse()can be replaced by callingurllib.parse.parse_qs()directly on the desired query string, except formultipart/form-datainput, which can be handled as described forcgi.parse_multipart().cgi.parse_header()can be replaced with the functionality in theemailpackage, 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 theemailpackage (e.g.email.message.EmailMessageandemail.message.Message) which implements the same MIME RFCs, or with the multipart PyPI project.
(Contributed by Victor Stinner in gh-104773.)
cryptmodule and its private_cryptextension. Thehashlibmodule 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: Wrapper to the POSIX crypt library call and associated functionality.
(Contributed by Victor Stinner in gh-104773.)
imghdr: use the projects filetype, puremagic, or python-magic instead. (Contributed by Victor Stinner in gh-104773.)mailcap. Themimetypesmodule 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 PyPI nntplib 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 thesubprocessmodule 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: thebase64module is a modern alternative. (Contributed by Victor Stinner in gh-104773.)xdrlib. (Contributed by Victor Stinner in gh-104773.)
2to3¶
Remove the
2to3program and thelib2to3module, deprecated in Python 3.11. (Contributed by Victor Stinner in gh-104780.)
configparser¶
Remove the undocumented
configparser.LegacyInterpolationclass, 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
importlib.resourcesdeprecated methods:contents()is_resource()open_binary()open_text()path()read_binary()read_text()
Use
importlib.resources.files()instead. Refer to importlib-resources: Migrating from Legacy for migration advice. (Contributed by Jason R. Coombs in gh-106532.)
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.Pathobjects as context managers. This functionality was deprecated and made a no-op in Python 3.9.
re¶
Remove undocumented, never working, and deprecated
re.templatefunction andre.TEMPLATEflag (andre.Talias). (Contributed by Serhiy Storchaka and Nikita Sobolev in gh-105687.)
tkinter¶
Remove the
tkinter.tixmodule, deprecated in Python 3.6. The third-party Tix library which the module wrapped is unmaintained. (Contributed by Zachary Ware in gh-75552.)
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.ioandtyping.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.TypedDicttypes, deprecated in Python 3.11. (Contributed by Tomas Roun in gh-104786.)
unittest¶
Removed the following
unittestfunctions, deprecated in Python 3.11:unittest.findTestCases()unittest.makeSuite()unittest.getTestCaseNames()
Use
TestLoadermethods 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: use the context parameter instead. Please usessl.SSLContext.load_cert_chain()instead, 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
webbrowserMacOSXclass, deprecated in Python 3.11. Use theMacOSXOSAScriptclass (introduced in Python 3.2) instead. (Contributed by Hugo van Kemenade in gh-104804.)Remove deprecated
webbrowser.MacOSXOSAScript._nameattribute. Usewebbrowser.MacOSXOSAScript.nameattribute instead. (Contributed by Nikita Sobolev in gh-105546.)
Others¶
None yet
CPython bytecode changes¶
The oparg of
YIELD_VALUEis now1if the yield is part of a yield-from or await, and0otherwise. The oparg ofRESUMEwas 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.)
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¶
tkinter.Text.count()now always returns an integer if one or less counting options are specified. Previously it could return a single count as a 1-tuple, an integer (only if option"update"was specified) orNoneif no items found. The result is now the same ifwantobjectsis set to0. (Contributed by Serhiy Storchaka in gh-97928.)Functions
PyDict_GetItem(),PyDict_GetItemString(),PyMapping_HasKey(),PyMapping_HasKeyString(),PyObject_HasAttr(),PyObject_HasAttrString(), andPySys_GetObject(), which clear all errors occurred during calling the function, report now them usingsys.unraisablehook(). You can consider to replace these functions with other functions as recomended in the documentation. (Contributed by Serhiy Storchaka in gh-106672.)An
OSErroris now raised bygetpass.getuser()for any failure to retrieve a username, instead ofImportErroron non-Unix platforms orKeyErroron Unix platforms where the password database is empty.
Build Changes¶
Autoconf 2.71 and aclocal 1.16.4 is now required to regenerate the
configurescript. (Contributed by Christian Heimes in gh-89886.)SQLite 3.15.2 or newer is required to build the
sqlite3extension module. (Contributed by Erlend Aasland in gh-105875.)Python built with
configure--with-trace-refs(tracing references) is now ABI compatible with 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,md5,resource,winsound,_ctypes_test,_multiprocessing.posixshmem,_scproxy,_stat,_testimportmultipleand_uuidC extensions are now built with the limited C API. (Contributed by Victor Stinner in gh-85283.)
C API Changes¶
New Features¶
You no longer have to define the
PY_SSIZE_T_CLEANmacro before includingPython.hwhen using#formats in format codes. APIs accepting the format codes always usePy_ssize_tfor#formats. (Contributed by Inada Naoki in gh-104922.)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, orNULLif 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 raiseAttributeErrorif 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 raiseKeyErrorif 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
1for true and0for false, but also-1for 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.)Added
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_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.)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_DICTflag. 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 Pythontupleobject. (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 to customize the warning mesage. (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 raisingKeyErrorif the key missing. (Contributed by Stefan Behnel and Victor Stinner in gh-111262.)
Porting to Python 3.13¶
Python.hno 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_Hmacro. (Contributed by Victor Stinner in gh-108765.)Python.hno 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.)If the
Py_LIMITED_APImacro is defined,Py_BUILD_CORE,Py_BUILD_CORE_BUILTINandPy_BUILD_CORE_MODULEmacros are now undefined by<Python.h>. (Contributed by Victor Stinner in gh-85283.)The old trashcan macros
Py_TRASHCAN_SAFE_BEGINandPy_TRASHCAN_SAFE_ENDwere removed. They should be replaced by the new macrosPy_TRASHCAN_BEGINandPy_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_BEGINhas a second argument which should be the deallocation function it is in.On Windows,
Python.hno longer includes the<stddef.h>standard header file. If needed, it should now be included explicitly. For example, it providesoffsetof()function, andsize_tandptrdiff_ttypes. Including<stddef.h>explicitly was already needed by all other platforms, theHAVE_STDDEF_Hmacro is only defined on Windows. (Contributed by Victor Stinner in gh-108765.)
Deprecated¶
Passing optional arguments maxsplit, count and flags in module-level functions
re.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.)Deprecate the old
Py_UNICODEandPY_UNICODE_TYPEtypes: use directly thewchar_ttype instead. Since Python 3.3,Py_UNICODEandPY_UNICODE_TYPEare just aliases towchar_t. (Contributed by Victor Stinner in gh-105156.)Deprecate old Python initialization functions:
PySys_ResetWarnOptions(): clearsys.warnoptionsandwarnings.filtersinstead.Py_GetExecPrefix(): getsys.exec_prefixinstead.Py_GetPath(): getsys.pathinstead.Py_GetPrefix(): getsys.prefixinstead.Py_GetProgramFullPath(): getsys.executableinstead.Py_GetProgramName(): getsys.executableinstead.Py_GetPythonHome(): getPyConfig.homeorPYTHONHOMEenvironment 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.)
Removed¶
Removed chained
classmethoddescriptors (introduced in bpo-19072). 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.)Remove many APIs (functions, macros, variables) with names prefixed by
_Pyor_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 @vstinnerto 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 atupleand must not be NULL, keyword arguments must be adictor NULL, whereas removed functions checked arguments type and accepted NULL 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 缓冲协议 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.warnoptionsinstead.PySys_AddWarnOption(): usePyConfig.warnoptionsinstead.PySys_AddXOption(): usePyConfig.xoptionsinstead.PySys_HasWarnOptions(): usePyConfig.xoptionsinstead.PySys_SetArgvEx(): setPyConfig.argvinstead.PySys_SetArgv(): setPyConfig.argvinstead.PySys_SetPath(): setPyConfig.module_search_pathsinstead.Py_SetPath(): setPyConfig.module_search_pathsinstead.Py_SetProgramName(): setPyConfig.program_nameinstead.Py_SetPythonHome(): setPyConfig.homeinstead.Py_SetStandardStreamEncoding(): setPyConfig.stdio_encodinginstead, and set also maybePyConfig.legacy_windows_stdio(on Windows)._Py_SetProgramFullPath(): setPyConfig.executableinstead.
Use the new
PyConfigAPI of the Python Initialization Configuration instead (PEP 587), added to Python 3.8. (Contributed by Victor Stinner in gh-105145.)Remove the old trashcan macros
Py_TRASHCAN_SAFE_BEGINandPy_TRASHCAN_SAFE_END. They should be replaced by the new macrosPy_TRASHCAN_BEGINandPy_TRASHCAN_END. 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.)Remove
PyEval_InitThreads()andPyEval_ThreadsInitialized()functions, deprecated in Python 3.9. Since Python 3.7,Py_Initialize()always creates the GIL: callingPyEval_InitThreads()did 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.hheader 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.)
Pending Removal in Python 3.14¶
Creating immutable types (
Py_TPFLAGS_IMMUTABLETYPE) with mutable bases using the C API.Global configuration variables:
Py_HashRandomizationFlag: usePyConfig.use_hash_seedandPyConfig.hash_seedPy_LegacyWindowsFSEncodingFlag: usePyPreConfig.legacy_windows_fs_encodingPy_LegacyWindowsStdioFlag: usePyConfig.legacy_windows_stdioPy_FileSystemDefaultEncoding: usePyConfig.filesystem_encodingPy_HasFileSystemDefaultEncoding: usePyConfig.filesystem_encodingPy_FileSystemDefaultEncodeErrors: usePyConfig.filesystem_errorsPy_UTF8Mode: usePyPreConfig.utf8_mode(seePy_PreInitialize())
The
Py_InitializeFromConfig()API should be used withPyConfiginstead.
Pending Removal in Python 3.15¶
PyImport_ImportModuleNoBlock(): usePyImport_ImportModule().PyWeakref_GET_OBJECT(): usePyWeakref_GetRef()instead.PyWeakref_GetObject(): usePyWeakref_GetRef()instead.Py_UNICODE_WIDEtype: usewchar_tinstead.Py_UNICODEtype: usewchar_tinstead.Python initialization functions:
PySys_ResetWarnOptions(): clearsys.warnoptionsandwarnings.filtersinstead.Py_GetExecPrefix(): getsys.exec_prefixinstead.Py_GetPath(): getsys.pathinstead.Py_GetPrefix(): getsys.prefixinstead.Py_GetProgramFullPath(): getsys.executableinstead.Py_GetProgramName(): getsys.executableinstead.Py_GetPythonHome(): getPyConfig.homeorPYTHONHOMEenvironment variable instead.
Pending Removal in Future Versions¶
The following APIs were deprecated in earlier Python versions and will be removed, although there is currently no date scheduled for their removal.
Py_TPFLAGS_HAVE_FINALIZE: no needed since Python 3.8.PyUnicode_AsDecodedObject().PyUnicode_AsDecodedUnicode().PyUnicode_AsEncodedObject().PyUnicode_AsEncodedUnicode().PyUnicode_READY(): not needed since Python 3.12._PyErr_ChainExceptions().PyBytesObject.ob_shashmember: callPyObject_Hash()instead.PyDictObject.ma_version_tagmember.TLS API:
PyThread_ReInitTLS(): no longer needed.
Remove undocumented
PY_TIMEOUT_MAXconstant from the limited C API. (Contributed by Victor Stinner in gh-110014.)
Regression Test Changes¶
Python built with
configure--with-pydebugnow supports a-X presite=package.modulecommand-line option. If used, it specifies a module that should be imported early in the lifecycle of the interpreter, beforesite.pyis executed. (Contributed by Łukasz Langa in gh-110769.)