Deprecations¶
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.)-
The child watcher classes
MultiLoopChildWatcher,FastChildWatcher,AbstractChildWatcherandSafeChildWatcherare 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 aDeprecationWarningif 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. 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.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 Contexts and start methods.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().
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versionandversion_info.execute()andexecutemany()if named placeholders are used and parameters is a sequence instead of adict.
typing:ByteString, deprecated since Python 3.9, now causes aDeprecationWarningto be emitted when it is used.urllib:urllib.parse.Quoteris deprecated: it was not intended to be a public API. (Contributed by Gregory P. Smith in gh-88168.)
Pending Removal in Python 3.15¶
The import system:
Setting
__cached__on a module while failing to set__spec__.cachedis deprecated. In Python 3.15,__cached__will cease to be set or take into consideration by the import system or standard library. (gh-97879)Setting
__package__on a module while failing to set__spec__.parentis deprecated. In Python 3.15,__package__will cease to be set or take into consideration by the import system or standard library. (gh-97879)
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The undocumented
ctypes.SetPointerType()function has been deprecated since Python 3.13.
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The obsolete and rarely used
CGIHTTPRequestHandlerhas been deprecated since Python 3.13. No direct replacement exists. Anything is better than CGI to interface a web server with a request handler.The
--cgiflag to the python -m http.server command-line interface has been deprecated since Python 3.13.
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load_module()method: useexec_module()instead.
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The
getdefaultlocale()function has been deprecated since Python 3.11. Its removal was originally planned for Python 3.13 (gh-90817), but has been postponed to Python 3.15. Usegetlocale(),setlocale(), andgetencoding()instead. (Contributed by Hugo van Kemenade in gh-111187.)
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PurePath.is_reserved()has been deprecated since Python 3.13. Useos.path.isreserved()to detect reserved paths on Windows.
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java_ver()has been deprecated since Python 3.13. This function is only useful for Jython support, has a confusing API, and is largely untested.
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The check_home argument of
sysconfig.is_python_build()has been deprecated since Python 3.12.
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RLock()will take no arguments in Python 3.15. Passing any arguments has been deprecated since Python 3.14, as the Python version does not permit any arguments, but the C version allows any number of positional or keyword arguments, ignoring every argument.
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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 3.15. (Contributed by Nikita Sobolev in gh-101866.)
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The undocumented keyword argument syntax for creating
NamedTupleclasses (e.g.Point = NamedTuple("Point", x=int, y=int)) has been deprecated since Python 3.13. Use the class-based syntax or the functional syntax instead.The
typing.no_type_check_decorator()decorator function has been deprecated since Python 3.13. After eight years in thetypingmodule, it has yet to be supported by any major type checker.
wave:The
getmark(),setmark(), andgetmarkers()methods of theWave_readandWave_writeclasses have been deprecated since Python 3.13.
Pending removal in Python 3.16¶
The import system:
Setting
__loader__on a module while failing to set__spec__.loaderis deprecated. In Python 3.16,__loader__will cease to be set or taken into consideration by the import system or the standard library.
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The
'u'format code (wchar_t) has been deprecated in documentation since Python 3.3 and at runtime since Python 3.13. Use the'w'format code (Py_UCS4) for Unicode characters instead.
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asyncio.iscoroutinefunction()is deprecated and will be removed in Python 3.16, useinspect.iscoroutinefunction()instead. (Contributed by Jiahao Li and Kumar Aditya in gh-122875.)
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Bitwise inversion on boolean types,
~Trueor~Falsehas been deprecated since Python 3.12, as it produces surprising and unintuitive results (-2and-1). Usenot xinstead for the logical negation of a Boolean. In the rare case that you need the bitwise inversion of the underlying integer, convert tointexplicitly (~int(x)).
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The
ExecErrorexception has been deprecated since Python 3.14. It has not been used by any function inshutilsince Python 3.4, and is now an alias ofRuntimeError.
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The
Class.get_methodsmethod has been deprecated since Python 3.14.
sys:The
_enablelegacywindowsfsencoding()function has been deprecated since Python 3.13. Use thePYTHONLEGACYWINDOWSFSENCODINGenvironment variable instead.
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The undocumented and unused
TarFile.tarfileattribute has been deprecated since Python 3.13.
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(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.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.Januaryandcalendar.Februaryconstants are deprecated and replaced bycalendar.JANUARYandcalendar.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.-
cache_from_source()debug_override parameter is deprecated: use the optimization parameter instead.
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EntryPointstuple interface.Implicit
Noneon return values.
logging: thewarn()method has been deprecated since Python 3.3, usewarning()instead.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_constantsandsre_parsemodules.shutil:rmtree()’s onerror parameter is deprecated in Python 3.12; use the onexc parameter instead.ssloptions and protocols:ssl.SSLContextwithout 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_SSLv3ssl.PROTOCOL_TLSssl.PROTOCOL_TLSv1ssl.PROTOCOL_TLSv1_1ssl.PROTOCOL_TLSv1_2ssl.TLSVersion.SSLv3ssl.TLSVersion.TLSv1ssl.TLSVersion.TLSv1_1
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 notNonefrom a test case.urllib.parsedeprecated functions:urlparse()insteadsplitattr()splithost()splitnport()splitpasswd()splitport()splitquery()splittag()splittype()splituser()splitvalue()to_bytes()
urllib.request:URLopenerandFancyURLopenerstyle 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 anElementis deprecated. In a future release it will always returnTrue. Prefer explicitlen(elem)orelem is not Nonetests instead.zipimport.zipimporter.load_module()is deprecated: useexec_module()instead.
C API Deprecations¶
Pending Removal in Python 3.14¶
The
ma_version_tagfield inPyDictObjectfor extension modules (PEP 699; gh-101193).Creating
immutable typeswith mutable bases (gh-95388).Functions to configure Python’s initialization, deprecated in Python 3.11:
PySys_SetArgvEx(): SetPyConfig.argvinstead.PySys_SetArgv(): SetPyConfig.argvinstead.Py_SetProgramName(): SetPyConfig.program_nameinstead.Py_SetPythonHome(): SetPyConfig.homeinstead.
The
Py_InitializeFromConfig()API should be used withPyConfiginstead.Global configuration variables:
Py_DebugFlag: UsePyConfig.parser_debuginstead.Py_VerboseFlag: UsePyConfig.verboseinstead.Py_QuietFlag: UsePyConfig.quietinstead.Py_InteractiveFlag: UsePyConfig.interactiveinstead.Py_InspectFlag: UsePyConfig.inspectinstead.Py_OptimizeFlag: UsePyConfig.optimization_levelinstead.Py_NoSiteFlag: UsePyConfig.site_importinstead.Py_BytesWarningFlag: UsePyConfig.bytes_warninginstead.Py_FrozenFlag: UsePyConfig.pathconfig_warningsinstead.Py_IgnoreEnvironmentFlag: UsePyConfig.use_environmentinstead.Py_DontWriteBytecodeFlag: UsePyConfig.write_bytecodeinstead.Py_NoUserSiteDirectory: UsePyConfig.user_site_directoryinstead.Py_UnbufferedStdioFlag: UsePyConfig.buffered_stdioinstead.Py_HashRandomizationFlag: UsePyConfig.use_hash_seedandPyConfig.hash_seedinstead.Py_IsolatedFlag: UsePyConfig.isolatedinstead.Py_LegacyWindowsFSEncodingFlag: UsePyPreConfig.legacy_windows_fs_encodinginstead.Py_LegacyWindowsStdioFlag: UsePyConfig.legacy_windows_stdioinstead.Py_FileSystemDefaultEncoding: UsePyConfig.filesystem_encodinginstead.Py_HasFileSystemDefaultEncoding: UsePyConfig.filesystem_encodinginstead.Py_FileSystemDefaultEncodeErrors: UsePyConfig.filesystem_errorsinstead.Py_UTF8Mode: UsePyPreConfig.utf8_modeinstead. (seePy_PreInitialize())
The
Py_InitializeFromConfig()API should be used withPyConfiginstead.
Pending Removal in Python 3.15¶
The bundled copy of
libmpdecimal.The
PyImport_ImportModuleNoBlock(): UsePyImport_ImportModule()instead.PyWeakref_GetObject()andPyWeakref_GET_OBJECT(): UsePyWeakref_GetRef()instead.Py_UNICODEtype and thePy_UNICODE_WIDEmacro: Usewchar_tinstead.Python initialization functions:
PySys_ResetWarnOptions(): Clearsys.warnoptionsandwarnings.filtersinstead.Py_GetExecPrefix(): Getsys.base_exec_prefixandsys.exec_prefixinstead.Py_GetPath(): Getsys.pathinstead.Py_GetPrefix(): Getsys.base_prefixandsys.prefixinstead.Py_GetProgramFullPath(): Getsys.executableinstead.Py_GetProgramName(): Getsys.executableinstead.Py_GetPythonHome(): GetPyConfig.homeor thePYTHONHOMEenvironment 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_shashmember: callPyObject_Hash()instead.PyDictObject.ma_version_tagmember.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.