Python 3.12 有什麼新功能

編輯者:

Adam Turner

本文介紹了 Python 3.12 與 3.11 相比多了哪些新功能。 Python 3.12 於 2023 年 10 月 2 日發布。完整詳情請見changelog。

也參考

PEP 693 -- Python 3.12 發佈時程

發布重點摘要

Python 3.12 是 Python 程式語言的穩定版本，包含了語言和標準函式庫的綜合變更。標準函式庫的變更主要集中在清理棄用的 API、可用性和正確性。值得注意的是，distutils 套件已從標準函式庫中移除。os 和pathlib 中的檔案系統支援進行了許多改進，並且有數個模組得到更好的效能。

語言變更主要集中在可用性，因為f-字串已經移除了許多限制，並且持續改進 'Did you mean ...' 建議。新的型別參數語法和type 陳述式改進了泛型型別和型別別名在與靜態型別檢查器一起使用上的效率。

這篇文章並不試圖提供所有新功能的完整規格，而是提供一個方便的概覽。完整詳情應參考文件，如標準函式庫參考和語言參考。如果你想了解某個新功能的完整實作和設計理念，請參考該功能的 PEP；但請注意 PEP 通常在功能完全實作後就不再更新。

新增語法特性：

新增語法特性：

直譯器改進：

Python 資料模型改進：

標準函式庫中的顯著改進

安全性改進：

  • Replace the builtinhashlib implementations ofSHA1, SHA3, SHA2-384, SHA2-512, and MD5 with formally verified code from theHACL* project.These builtin implementations remain as fallbacks that are only used whenOpenSSL does not provide them.

C API 改進：

CPython 實作改進：

  • PEP 709, comprehension inlining

  • CPython support for the Linuxperf profiler

  • Implement stack overflow protection on supported platforms

新增型別特性：

重要的棄用、刪除或限制：

  • PEP 623: Removewstr from Unicode objects in Python's C API,reducing the size of everystr object by at least 8 bytes.

  • PEP 632: Remove thedistutils package.Seethe migration guidefor advice replacing the APIs it provided.The third-partySetuptoolspackage continues to providedistutils,if you still require it in Python 3.12 and beyond.

  • gh-95299: Do not pre-installsetuptools in virtual environmentscreated withvenv.This means thatdistutils,setuptools,pkg_resources,andeasy_install will no longer available by default; to access theserunpipinstallsetuptools in theactivatedvirtual environment.

  • asynchat、asyncore 和imp 模組以及幾個unittest.TestCase 的方法別名已被刪除。

新增功能

PEP 695：型別參數語法

Generic classes and functions underPEP 484 were declared using a verbose syntaxthat left the scope of type parameters unclear and required explicit declarations ofvariance.

PEP 695 introduces a new, more compact and explicit way to creategeneric classes andfunctions:

defmax[T](args:Iterable[T])->T:...classlist[T]:def__getitem__(self,index:int,/)->T:...defappend(self,element:T)->None:...

In addition, the PEP introduces a new way to declaretype aliasesusing thetype statement, which creates an instance ofTypeAliasType:

typePoint=tuple[float,float]

型別別名也可以是泛型：

typePoint[T]=tuple[T,T]

The new syntax allows declaringTypeVarTupleandParamSpec parameters, as well asTypeVarparameters with bounds or constraints:

typeIntFunc[**P]=Callable[P,int]# ParamSpectypeLabeledTuple[*Ts]=tuple[str,*Ts]# TypeVarTupletypeHashableSequence[T:Hashable]=Sequence[T]# TypeVar with boundtypeIntOrStrSequence[T:(int,str)]=Sequence[T]# TypeVar with constraints

The value of type aliases and the bound and constraints of type variablescreated through this syntax are evaluated only on demand (seelazy evaluation). This means type aliases are able torefer to other types defined later in the file.

Type parameters declared through a type parameter list are visible within thescope of the declaration and any nested scopes, but not in the outer scope. Forexample, they can be used in the type annotations for the methods of a genericclass or in the class body. However, they cannot be used in the module scope afterthe class is defined. SeeType parameter lists for a detailed description of theruntime semantics of type parameters.

In order to support these scoping semantics, a new kind of scope is introduced,theannotation scope. Annotation scopes behave for themost part like function scopes, but interact differently with enclosing class scopes.In Python 3.13,annotations will also be evaluated inannotation scopes.

詳情請見PEP 695。

(PEP written by Eric Traut. Implementation by Jelle Zijlstra, Eric Traut,and others ingh-103764.)

PEP 701: Syntactic formalization of f-strings

PEP 701 lifts some restrictions on the usage off-strings.Expression components inside f-strings can now be any valid Python expression,including strings reusing the same quote as the containing f-string,multi-line expressions, comments, backslashes, and unicode escape sequences.Let's cover these in detail:

  • Quote reuse: in Python 3.11, reusing the same quotes as the enclosing f-stringraises aSyntaxError, forcing the user to either use other availablequotes (like using double quotes or triple quotes if the f-string uses singlequotes). In Python 3.12, you can now do things like this:

    >>>songs=['Take me back to Eden','Alkaline','Ascensionism']>>>f"This is the playlist:{", ".join(songs)}"'This is the playlist: Take me back to Eden, Alkaline, Ascensionism'

    Note that before this change there was no explicit limit in how f-strings canbe nested, but the fact that string quotes cannot be reused inside theexpression component of f-strings made it impossible to nest f-stringsarbitrarily. In fact, this is the most nested f-string that could be written:

    >>>f"""{f'''{f'{f"{1+1}"}'}'''}"""'2'

    As now f-strings can contain any valid Python expression inside expressioncomponents, it is now possible to nest f-strings arbitrarily:

    >>>f"{f"{f"{f"{f"{f"{1+1}"}"}"}"}"}"'2'

  • Multi-line expressions and comments: In Python 3.11, f-string expressionsmust be defined in a single line, even if the expression within the f-stringcould normally span multiple lines(like literal lists being defined over multiple lines),making them harder to read. In Python 3.12 you can now define f-stringsspanning multiple lines, and add inline comments:

    >>> f"This is the playlist: {", ".join([...     'Take me back to Eden',  # My, my, those eyes like fire...     'Alkaline',              # Not acid nor alkaline...     'Ascensionism'           # Take to the broken skies at last... ])}"'This is the playlist: Take me back to Eden, Alkaline, Ascensionism'

  • Backslashes and unicode characters: before Python 3.12 f-string expressionscouldn't contain any\ character. This also affected unicodeescapesequences (such as\N{snowman}) as these containthe\N part that previously could not be part of expression components off-strings. Now, you can define expressions like this:

    >>>print(f"This is the playlist:{"\n".join(songs)}")This is the playlist: Take me back to EdenAlkalineAscensionism>>>print(f"This is the playlist:{"\N{BLACK HEART SUIT}".join(songs)}")This is the playlist: Take me back to Eden♥Alkaline♥Ascensionism

詳情請見PEP 701。

As a positive side-effect of how this feature has been implemented (by parsing f-stringswiththe PEG parser), now error messages for f-strings are more preciseand include the exact location of the error. For example, in Python 3.11, the followingf-string raises aSyntaxError:

>>>my_string=f"{xzy}"+f"{1+1}"  File"<stdin>", line1(xzy)^^^SyntaxError:f-string: invalid syntax. Perhaps you forgot a comma?

but the error message doesn't include the exact location of the error within the line andalso has the expression artificially surrounded by parentheses. In Python 3.12, as f-stringsare parsed with the PEG parser, error messages can be more precise and show the entire line:

>>>my_string=f"{xzy}"+f"{1+1}"  File"<stdin>", line1my_string=f"{xzy}"+f"{1+1}"^^^SyntaxError:invalid syntax. Perhaps you forgot a comma?

(Contributed by Pablo Galindo, Batuhan Taskaya, Lysandros Nikolaou, CristiánMaureira-Fredes and Marta Gómez ingh-102856. PEP written by Pablo Galindo,Batuhan Taskaya, Lysandros Nikolaou and Marta Gómez).

PEP 684：直譯器各別持有的 GIL

PEP 684 引入了直譯器各別持有的GIL，因此子直譯器現在可以使用各個直譯器特有的 GIL 來建立。這使得 Python 程式可以充分利用多個 CPU 核心。目前這僅透過 C-API 使用，不過 Python API預計在 3.13 中釋出。

Use the newPy_NewInterpreterFromConfig() function tocreate an interpreter with its own GIL:

PyInterpreterConfigconfig={.check_multi_interp_extensions=1,.gil=PyInterpreterConfig_OWN_GIL,};PyThreadState*tstate=NULL;PyStatusstatus=Py_NewInterpreterFromConfig(&tstate,&config);if(PyStatus_Exception(status)){return-1;}/* 新的直譯器現在會在目前執行緒中啟用。 */

For further examples how to use the C-API for sub-interpreters with aper-interpreter GIL, seeModules/_xxsubinterpretersmodule.c.

（由 Eric Snow 於gh-104210 等貢獻。）

PEP 669: Low impact monitoring for CPython

PEP 669 defines a newAPI for profilers,debuggers, and other tools to monitor events in CPython.It covers a wide range of events, including calls,returns, lines, exceptions, jumps, and more.This means that you only pay for what you use, providing supportfor near-zero overhead debuggers and coverage tools.Seesys.monitoring for details.

（由 Mark Shannon 於gh-103082 中貢獻。）

PEP 688: Making the buffer protocol accessible in Python

PEP 688 introduces a way to use thebuffer protocolfrom Python code. Classes that implement the__buffer__() methodare now usable as buffer types.

The newcollections.abc.Buffer ABC provides a standardway to represent buffer objects, for example in type annotations.The newinspect.BufferFlags enum represents the flags thatcan be used to customize buffer creation.(Contributed by Jelle Zijlstra ingh-102500.)

PEP 709: Comprehension inlining

Dictionary, list, and set comprehensions are now inlined, rather than creating anew single-use function object for each execution of the comprehension. Thisspeeds up execution of a comprehension by up to two times.SeePEP 709 for further details.

Comprehension iteration variables remain isolated and don't overwrite avariable of the same name in the outer scope, nor are they visible after thecomprehension. Inlining does result in a few visible behavior changes:

  • There is no longer a separate frame for the comprehension in tracebacks,and tracing/profiling no longer shows the comprehension as a function call.

  • Thesymtable module will no longer produce child symbol tables for eachcomprehension; instead, the comprehension's locals will be included in theparent function's symbol table.

  • Callinglocals() inside a comprehension now includes variablesfrom outside the comprehension, and no longer includes the synthetic.0variable for the comprehension "argument".

  • A comprehension iterating directly overlocals() (e.g.[kforkinlocals()]) may see "RuntimeError: dictionary changed size during iteration"when run under tracing (e.g. code coverage measurement). This is the samebehavior already seen in e.g.forkinlocals():. To avoid the error, firstcreate a list of keys to iterate over:keys=list(locals());[kforkinkeys].

（由 Carl Meyer 和 Vladimir Matveev 於PEP 709 中貢獻。）

Improved Error Messages

  • Modules from the standard library are now potentially suggested as part ofthe error messages displayed by the interpreter when aNameError israised to the top level. (Contributed by Pablo Galindo ingh-98254.)

    >>>sys.version_infoTraceback (most recent call last):  File"<stdin>", line1, in<module>NameError:name 'sys' is not defined. Did you forget to import 'sys'?

  • Improve the error suggestion forNameError exceptions for instances.Now if aNameError is raised in a method and the instance has anattribute that's exactly equal to the name in the exception, the suggestionwill includeself.<NAME> instead of the closest match in the methodscope. (Contributed by Pablo Galindo ingh-99139.)

    >>>classA:...def__init__(self):...self.blech=1......deffoo(self):...somethin=blech...>>>A().foo()Traceback (most recent call last):  File"<stdin>", line1somethin=blech^^^^^NameError:name 'blech' is not defined. Did you mean: 'self.blech'?

  • Improve theSyntaxError error message when the user typesimportxfromy instead offromyimportx. (Contributed by Pablo Galindo ingh-98931.)

    >>>importa.y.zfromb.y.zTraceback (most recent call last):  File"<stdin>", line1importa.y.zfromb.y.z^^^^^^^^^^^^^^^^^^^^^^^SyntaxError:Did you mean to use 'from ... import ...' instead?

  • ImportError exceptions raised from failedfrom<module>import<name> statements now include suggestions for the value of<name> based on theavailable names in<module>. (Contributed by Pablo Galindo ingh-91058.)

    >>>fromcollectionsimportchainmapTraceback (most recent call last):  File"<stdin>", line1, in<module>ImportError:cannot import name 'chainmap' from 'collections'. Did you mean: 'ChainMap'?

型別提示相關的新特性

本節涵蓋了影響型別提示和typing 模組的主要變更。

PEP 692: UsingTypedDict for more precise**kwargs typing

Typing**kwargs in a function signature as introduced byPEP 484 allowedfor valid annotations only in cases where all of the**kwargs were of thesame type.

PEP 692 specifies a more precise way of typing**kwargs by relying ontyped dictionaries:

fromtypingimportTypedDict,UnpackclassMovie(TypedDict):name:stryear:intdeffoo(**kwargs:Unpack[Movie]):...

詳情請見PEP 692。

（由 Franek Magiera 於gh-103629 中貢獻。）

PEP 698: Override Decorator for Static Typing

A new decoratortyping.override() has been added to thetypingmodule. It indicates to type checkers that the method is intended to overridea method in a superclass. This allows type checkers to catch mistakes wherea method that is intended to override something in a base classdoes not in fact do so.

範例：

fromtypingimportoverrideclassBase:defget_color(self)->str:return"blue"classGoodChild(Base):@override# ok: overrides Base.get_colordefget_color(self)->str:return"yellow"classBadChild(Base):@override# type checker error: does not override Base.get_colordefget_colour(self)->str:return"red"

詳情請見PEP 698。

（由 Steven Troxler 於gh-101561 中貢獻。）

其他語言更動

  • The parser now raisesSyntaxError when parsing source code containingnull bytes. (Contributed by Pablo Galindo ingh-96670.)

  • A backslash-character pair that is not a valid escape sequence now generatesaSyntaxWarning, instead ofDeprecationWarning.For example,re.compile("\d+\.\d+") now emits aSyntaxWarning("\d" is an invalid escape sequence, use raw strings for regularexpression:re.compile(r"\d+\.\d+")).In a future Python version,SyntaxError will eventually be raised,instead ofSyntaxWarning.(Contributed by Victor Stinner ingh-98401.)

  • Octal escapes with value larger than0o377 (ex:"\477"), deprecatedin Python 3.11, now produce aSyntaxWarning, instead ofDeprecationWarning.In a future Python version they will be eventually aSyntaxError.(Contributed by Victor Stinner ingh-98401.)

  • Variables used in the target part of comprehensions that are not stored tocan now be used in assignment expressions (:=).For example, in[(b:=1)fora,b.propinsome_iter], the assignment tob is now allowed. Note that assigning to variables stored to in the targetpart of comprehensions (likea) is still disallowed, as perPEP 572.(Contributed by Nikita Sobolev ingh-100581.)

  • Exceptions raised in a class or type's__set_name__ method are no longerwrapped by aRuntimeError. Context information is added to theexception as aPEP 678 note. (Contributed by Irit Katriel ingh-77757.)

  • When atry-except* construct handles the entireExceptionGroupand raises one other exception, that exception is no longer wrapped in anExceptionGroup. Also changed in version 3.11.4. (Contributed by IritKatriel ingh-103590.)

  • The Garbage Collector now runs only on the eval breaker mechanism of thePython bytecode evaluation loop instead of object allocations. The GC canalso run whenPyErr_CheckSignals() is called so C extensions thatneed to run for a long time without executing any Python code also have achance to execute the GC periodically. (Contributed by Pablo Galindo ingh-97922.)

  • All builtin and extension callables expecting boolean parameters now acceptarguments of any type instead of justbool andint.(Contributed by Serhiy Storchaka ingh-60203.)

  • memoryview now supports the half-float type (the "e" format code).(Contributed by Donghee Na and Antoine Pitrou ingh-90751.)

  • slice objects are now hashable, allowing them to be used as dict keys andset items. (Contributed by Will Bradshaw, Furkan Onder, and Raymond Hettinger ingh-101264.)

  • sum() now uses Neumaier summation to improve accuracy and commutativitywhen summing floats or mixed ints and floats.(Contributed by Raymond Hettinger ingh-100425.)

  • ast.parse() now raisesSyntaxError instead ofValueErrorwhen parsing source code containing null bytes. (Contributed by Pablo Galindoingh-96670.)

  • The extraction methods intarfile, andshutil.unpack_archive(),have a new afilter argument that allows limiting tar features than may besurprising or dangerous, such as creating files outside the destinationdirectory.Seetarfile extraction filters for details.In Python 3.14, the default will switch to'data'.(Contributed by Petr Viktorin inPEP 706.)

  • types.MappingProxyType instances are now hashable if the underlyingmapping is hashable.(Contributed by Serhiy Storchaka ingh-87995.)

  • Addsupport for the perf profiler through the newenvironment variablePYTHONPERFSUPPORTand command-line option-Xperf,as well as the newsys.activate_stack_trampoline(),sys.deactivate_stack_trampoline(),andsys.is_stack_trampoline_active() functions.(Design by Pablo Galindo. Contributed by Pablo Galindo and Christian Heimeswith contributions from Gregory P. Smith [Google] and Mark Shannoningh-96123.)

新增模組

  • None.

改進的模組

array

asyncio

calendar

csv

dis

  • Pseudo instruction opcodes (which are used by the compiler butdo not appear in executable bytecode) are now exposed in thedis module.HAVE_ARGUMENT is still relevant to real opcodes,but it is not useful for pseudo instructions. Use the newdis.hasarg collection instead.(Contributed by Irit Katriel ingh-94216.)

  • Add thedis.hasexc collection to signify instructions that setan exception handler. (Contributed by Irit Katriel ingh-94216.)

fractions

importlib.resources

inspect

itertools

  • 新增itertools.batched() 以將元素收集到大小均等的元組中，其中最後一批次可能比其他的少。（由 Raymond Hettinger 於gh-98363 中貢獻。）

math

  • 新增math.sumprod() 以計算乘積總和。（由 Raymond Hettinger 於gh-100485 中貢獻。）

  • Extendmath.nextafter() to include asteps argumentfor moving up or down multiple steps at a time. (Contributed byMatthias Goergens, Mark Dickinson, and Raymond Hettinger ingh-94906.)

os

  • Addos.PIDFD_NONBLOCK to open a file descriptorfor a process withos.pidfd_open() in non-blocking mode.(Contributed by Kumar Aditya ingh-93312.)

  • os.DirEntry now includes anos.DirEntry.is_junction()method to check if the entry is a junction.(Contributed by Charles Machalow ingh-99547.)

  • Addos.listdrives(),os.listvolumes() andos.listmounts()functions on Windows for enumerating drives, volumes and mount points.(Contributed by Steve Dower ingh-102519.)

  • os.stat() andos.lstat() are now more accurate on Windows.Thest_birthtime field will now be filled with the creation timeof the file, andst_ctime is deprecated but still contains thecreation time (but in the future will return the last metadata change,for consistency with other platforms).st_dev may be up to 64 bitsandst_ino up to 128 bits depending on your file system, andst_rdev is always set to zero rather than incorrect values.Both functions may be significantly faster on newer releases ofWindows. (Contributed by Steve Dower ingh-99726.)

os.path

pathlib

platform

  • Add support for detecting Windows 11 and Windows Server releases past 2012.Previously, lookups on Windows Server platforms newer than Windows Server 2012and on Windows 11 would returnWindows-10.(Contributed by Steve Dower ingh-89545.)

pdb

  • Add convenience variables to hold values temporarily for debug sessionand provide quick access to values like the current frame or the returnvalue.(Contributed by Tian Gao ingh-103693.)

random

shutil

  • shutil.make_archive() now passes theroot_dir argument to customarchivers which support it.In this case it no longer temporarily changes the current working directoryof the process toroot_dir to perform archiving.(Contributed by Serhiy Storchaka ingh-74696.)

  • shutil.rmtree() now accepts a new argumentonexc which is anerror handler likeonerror but which expects an exception instancerather than a(typ, val, tb) triplet.onerror is deprecated.(Contributed by Irit Katriel ingh-102828.)

  • shutil.which() now consults thePATHEXT environment variable tofind matches withinPATH on Windows even when the givencmd includesa directory component.(Contributed by Charles Machalow ingh-103179.)

    shutil.which() will callNeedCurrentDirectoryForExePathW whenquerying for executables on Windows to determine if the current workingdirectory should be prepended to the search path.(Contributed by Charles Machalow ingh-103179.)

    shutil.which() will return a path matching thecmd with a componentfromPATHEXT prior to a direct match elsewhere in the search path onWindows.(Contributed by Charles Machalow ingh-103179.)

sqlite3

statistics

sys

tempfile

threading

tkinter

  • tkinter.Canvas.coords() now flattens its arguments.It now accepts not only coordinates as separate arguments(x1,y1,x2,y2,...) and a sequence of coordinates([x1,y1,x2,y2,...]), but also coordinates grouped in pairs((x1,y1),(x2,y2),... and[(x1,y1),(x2,y2),...]),likecreate_*() methods.(Contributed by Serhiy Storchaka ingh-94473.)

tokenize

types

typing

  • isinstance() checks againstruntime-checkableprotocols now useinspect.getattr_static() rather thanhasattr() to lookup whetherattributes exist. This means that descriptors and__getattr__()methods are no longer unexpectedly evaluated duringisinstance() checksagainst runtime-checkable protocols. However, it may also mean that someobjects which used to be considered instances of a runtime-checkable protocolmay no longer be considered instances of that protocol on Python 3.12+, andvice versa. Most users are unlikely to be affected by this change.(Contributed by Alex Waygood ingh-102433.)

  • The members of a runtime-checkable protocol are now considered "frozen" atruntime as soon as the class has been created. Monkey-patching attributesonto a runtime-checkable protocol will still work, but will have no impact onisinstance() checks comparing objects to the protocol. For example:

    >>>fromtypingimportProtocol,runtime_checkable>>>@runtime_checkable...classHasX(Protocol):...x=1...>>>classFoo:......>>>f=Foo()>>>isinstance(f,HasX)False>>>f.x=1>>>isinstance(f,HasX)True>>>HasX.y=2>>>isinstance(f,HasX)# 沒有改變，即便 HasX 現在有 "y" 屬性True

    This change was made in order to speed upisinstance() checks againstruntime-checkable protocols.

  • The performance profile ofisinstance() checks againstruntime-checkableprotocols has changedsignificantly. Mostisinstance() checks against protocols with only a fewmembers should be at least 2x faster than in 3.11, and some may be 20xfaster or more. However,isinstance() checks against protocols with manymembers may be slower than in Python 3.11. (Contributed by AlexWaygood ingh-74690 andgh-103193.)

  • Alltyping.TypedDict andtyping.NamedTuple classes now have the__orig_bases__ attribute. (Contributed by Adrian Garcia Badaracco ingh-103699.)

  • 新增frozen_default 參數至typing.dataclass_transform()。（由 Erik De Bonte 於gh-99957 中貢獻。）

unicodedata

  • The Unicode database has been updated to version 15.0.0. (Contributed byBenjamin Peterson ingh-96734).

unittest

新增--durations 命令列選項，顯示 N 個最慢的測試案例：

python3-munittest--durations=3lib.tests.test_threading.....Slowesttestdurations----------------------------------------------------------------------1.210stest_timeout(Lib.test.test_threading.BarrierTests)1.003stest_default_timeout(Lib.test.test_threading.BarrierTests)0.518stest_timeout(Lib.test.test_threading.EventTests)(0.000durationshidden.Use-vtoshowthesedurations.)----------------------------------------------------------------------Ran158testsin9.869sOK(skipped=3)

（由 Giampaolo Rodola 於gh-48330 中貢獻。）

uuid

最佳化

  • Removewstr andwstr_length members from Unicode objects.It reduces object size by 8 or 16 bytes on 64bit platform. (PEP 623)(Contributed by Inada Naoki ingh-92536.)

  • Add experimental support for using the BOLT binary optimizer in the buildprocess, which improves performance by 1-5%.(Contributed by Kevin Modzelewski ingh-90536 and tuned by Donghee Na ingh-101525)

  • Speed up the regular expression substitution (functionsre.sub() andre.subn() and correspondingre.Pattern methods) forreplacement strings containing group references by 2--3 times.(Contributed by Serhiy Storchaka ingh-91524.)

  • 透過延遲運算較繁重的字串格式化來加速asyncio.Task 的建立。（由 Itamar Oren 於gh-103793 中貢獻。）

  • Thetokenize.tokenize() andtokenize.generate_tokens() functions areup to 64% faster as a side effect of the changes required to coverPEP 701 inthetokenize module. (Contributed by Marta Gómez Macías and Pablo Galindoingh-102856.)

  • Speed upsuper() method calls and attribute loads via thenewLOAD_SUPER_ATTR instruction. (Contributed by Carl Meyer andVladimir Matveev ingh-103497.)

CPython 位元組碼變更

Demos and Tools

  • Remove theTools/demo/ directory which contained old demo scripts. A copycan be found in theold-demos project.(Contributed by Victor Stinner ingh-97681.)

  • Remove outdated example scripts of theTools/scripts/ directory.A copy can be found in theold-demos project.(Contributed by Victor Stinner ingh-97669.)

已棄用

Python 3.13 中待移除的項目

模組（請見PEP 594）：

  • aifc

  • audioop

  • cgi

  • cgitb

  • chunk

  • crypt

  • imghdr

  • mailcap

  • msilib

  • nis

  • nntplib

  • ossaudiodev

  • pipes

  • sndhdr

  • spwd

  • sunau

  • telnetlib

  • uu

  • xdrlib

其他模組：

API：

Python 3.14 中待移除的項目

Python 3.15 中待移除的項目

  • 引入系統 (import system)：

    • 在模組上設定__cached__ 而沒有設定__spec__.cached 的做法已被棄用。在 Python 3.15 中，引入系統或標準函式庫將不再設定或考慮__cached__。(gh-97879)

    • 在模組上設定__package__ 而沒有設定__spec__.parent 的做法已被棄用。在 Python 3.15 中，引入系統或標準函式庫將不再設定或考慮__package__。(gh-97879)

  • ctypes：

    • 自 Python 3.13 起，未記錄的ctypes.SetPointerType() 函式已被棄用。

  • http.server：

    • 過時且很少使用的CGIHTTPRequestHandler 自 Python 3.13 起已被棄用。不存在直接的替代。任何東西都比 CGI 更好地將 Web 伺服器與請求處理程序介接起來。

    • 自 Python 3.13 起，python -m http.server 命令列介面的--cgi 旗標已被棄用。

  • importlib：

    • load_module() method：請改用exec_module()。

  • locale：

  • pathlib：

  • platform：

    • 自 Python 3.13 起，java_ver() 已被棄用。此函式僅對 Jython 支援有用，具有令人困惑的 API，基本上未經測試。

  • sysconfig：

  • threading：

    • RLock() 在 Python 3.15 中將不接受任何引數。自 Python 3.14 起，傳遞任何引數的用法已被棄用，因為 Python 版本不允許任何引數，但 C 版本允許任意數量的位置或關鍵字引數，並忽略每個引數。

  • types：

  • typing：

    • 用於建立NamedTuple 類別的未以文件記錄之關鍵字引數語法 (Point=NamedTuple("Point",x=int,y=int)) 已自 Python 3.13 棄用。請改用基於類別的語法或函式語法 (functional syntax)。

    • When using the functional syntax ofTypedDicts, failingto pass a value to thefields parameter (TD=TypedDict("TD")) orpassingNone (TD=TypedDict("TD",None)) has been deprecatedsince Python 3.13.UseclassTD(TypedDict):pass orTD=TypedDict("TD",{})to create a TypedDict with zero field.

    • 自 Python 3.13 起，typing.no_type_check_decorator() 裝飾器函式已被棄用。在typing 模組中使用了八年之後，它尚未得到任何主要型別檢查器的支援。

  • wave：

Python 3.16 中待移除的項目

  • 引入系統 (import system)：

    • 在模組上設定__loader__ 而沒有設定__spec__.loader 的做法將於 Python 3.16 被棄用。在 Python 3.16 中，引入系統或標準函式庫將不再設定或考慮__loader__。

  • array：

    • 自 Python 3.3 起，'u' 格式碼 (wchar_t) 在文件中已被棄用，自 Python 3.13 起在 runtime 已被棄用。請使用'w' 格式碼 (Py_UCS4) 來取代 Unicode 字元。

  • asyncio：

  • builtins：

    • 自 Python 3.12 起，布林型別的位元反轉~True 或~False 已被棄用，因為它會產生不預期且不直觀的結果（-2 和-1）。使用notx 代替布林值的邏輯否定。在極少數情況下，你需要對底層的整數進行位元反轉，請明確轉換為~int(x) (~int(x))。

  • shutil：

    • 自 Python 3.14 起，ExecError 例外已被棄用。自 Python 3.4 以來，它尚未被shutil 中的任何函式使用，現在是RuntimeError 的別名。

  • symtable：

  • sys：

  • tarfile：

    • 自 Python 3.13 起，未以文件記錄和未被使用的TarFile.tarfile 屬性已被棄用。

未來版本中的待移除項目

以下 API 將在未來被移除，雖然目前尚未安排移除日期。

  • argparse：已棄用巢狀引數群組和巢狀互斥群組。

  • builtins：

    • bool(NotImplemented)。

    • 產生器：throw(type,exc,tb) 和athrow(type,exc,tb) 簽名已被棄用：請改用throw(exc) 和athrow(exc)，為單引數簽名。

    • 目前 Python 接受數值字面值後面立即接關鍵字，例如0inx、1orx、0if1else2。它讓表達式模糊且容易混淆，如[0x1forxiny]（可以解釋為[0x1forxiny] 或[0x1forxiny]）。如果數值字面值後立即接and、else、for、if、in、is 和or 之一的關鍵字，則會引發語法警告。在未來版本中，它將被更改為語法錯誤。(gh-87999)

    • __index__() 和__int__() 方法回傳非 int 型別的支援：這些方法將需要回傳int 的嚴格子類別實例。

    • 回傳float 嚴格子類別__float__() 方法的支援：這些方法將需要回傳float 的實例。

    • 回傳complex 嚴格子類別__complex__() 方法的支援：這些方法將需要回傳complex 的實例。

    • 將int() 委派給__trunc__() 方法。

    • 在complex() 建構子中將複數作為real 或imag 引數傳遞現在已被棄用；它應該只作為單個位置引數傳遞。 (由 Serhiy Storchaka 於gh-109218 貢獻。)

  • calendar：calendar.January 和calendar.February 常數已被棄用並被calendar.JANUARY 和calendar.FEBRUARY 取代。 (由 Prince Roshan 於gh-103636 貢獻。)

  • codeobject.co_lnotab：請改用codeobject.co_lines() 方法。

  • datetime：

    • utcnow()：請改用datetime.datetime.now(tz=datetime.UTC)。

    • utcfromtimestamp()：請改用datetime.datetime.fromtimestamp(timestamp,tz=datetime.UTC)。

  • gettext：複數值必須是整數。

  • importlib：

  • importlib.metadata：

    • EntryPoints 元組介面。

    • 回傳值上的隱式None。

  • logging：自 Python 3.3 起，warn() 方法已被棄用，請改用warning()。

  • mailbox：已棄用 StringIO 輸入和文本模式，請改用 BytesIO 和二進位模式。

  • os：在多執行緒行程中呼叫os.register_at_fork()。

  • pydoc.ErrorDuringImport：exc_info 參數的元組值已被棄用，請用例外實例。

  • re：現在對正規表示式中的數值群組參照和群組名稱用了更嚴格的規則。現在只有 ASCII 數碼序列被接受作為數值參照。位元組模式和替換字串中的群組名稱現在只能包含 ASCII 字母、數碼和底線。（由 Serhiy Storchaka 於gh-91760 貢獻。）

  • sre_compile、sre_constants 和sre_parse 模組。

  • shutil：rmtree() 的onerror 參數在 Python 3.12 中已被棄用；請改用onexc 參數。

  • ssl 選項和協定：

    • 不帶協定引數的ssl.SSLContext 已被棄用。

    • ssl.SSLContext：set_npn_protocols() 和selected_npn_protocol() 已被棄用：請改用 ALPN。

    • ssl.OP_NO_SSL* 選項

    • ssl.OP_NO_TLS* 選項

    • ssl.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

  • threading 方法：

  • typing.Text (gh-92332)。

  • unittest.IsolatedAsyncioTestCase：從測試案例中回傳非None 的值已被棄用。

  • urllib.parse 已棄用函式：請改用urlparse()。

    • splitattr()

    • splithost()

    • splitnport()

    • splitpasswd()

    • splitport()

    • splitquery()

    • splittag()

    • splittype()

    • splituser()

    • splitvalue()

    • to_bytes()

  • urllib.request：呼叫請求的URLopener 和FancyURLopener 風格已被棄用。請改用更新的urlopen() 函式和方法。

  • wsgiref：SimpleHandler.stdout.write() 不應該進行部分寫入。

  • xml.etree.ElementTree：已棄用對Element 的真值測試。在未來版本中，它將始終回傳True。請改用明確的len(elem) 或elemisnotNone 測試。

  • zipimport.zipimporter.load_module() 已被棄用：請改用exec_module()。

已移除

asynchat 和 asyncore

  • These two modules have been removedaccording to the schedule inPEP 594,having been deprecated in Python 3.6.Useasyncio instead.(Contributed by Nikita Sobolev ingh-96580.)

configparser

distutils

  • Remove thedistutils package. It was deprecated in Python 3.10 byPEP 632 "Deprecate distutils module". For projects still usingdistutils and cannot be updated to something else, thesetuptoolsproject can be installed: it still providesdistutils.(Contributed by Victor Stinner ingh-92584.)

ensurepip

  • Remove the bundled setuptools wheel fromensurepip,and stop installing setuptools in environments created byvenv.

    pip(>=22.1) does not require setuptools to be installed in theenvironment.setuptools-based (anddistutils-based) packagescan still be used withpipinstall, since pip will providesetuptools in the build environment it uses for building apackage.

    easy_install,pkg_resources,setuptools anddistutilsare no longer provided by default in environments created withvenv or bootstrapped withensurepip, since they are part ofthesetuptools package. For projects relying on these at runtime,thesetuptools project should be declared as a dependency andinstalled separately (typically, using pip).

    （由 Pradyun Gedam 於gh-95299 中貢獻。）

enum

  • 移除enum 的EnumMeta.__getattr__，對於列舉屬性的存取不再會需要它。

ftplib

  • 移除ftplib 的FTP_TLS.ssl_version 類別屬性：請改用context 參數。（由 Victor Stinner 於gh-94172 中貢獻。）

gzip

  • Remove thefilename attribute ofgzip'sgzip.GzipFile,deprecated since Python 2.6, use thename attributeinstead. In write mode, thefilename attribute added'.gz' fileextension if it was not present.(Contributed by Victor Stinner ingh-94196.)

hashlib

importlib

  • 現已完成清理importlib 中許多過去已經棄用的東西：

    • 對module_repr() 的參照和支援已刪除。（由 Barry Warsaw 在gh-97850 中貢獻。）

    • importlib.util.set_package,importlib.util.set_loader andimportlib.util.module_for_loader have all been removed. (Contributed byBrett Cannon and Nikita Sobolev ingh-65961 andgh-97850.)

    • Support forfind_loader() andfind_module() APIs have beenremoved. (Contributed by Barry Warsaw ingh-98040.)

    • importlib.abc.Finder,pkgutil.ImpImporter, andpkgutil.ImpLoaderhave been removed. (Contributed by Barry Warsaw ingh-98040.)

imp

  • imp 模組已被移除。（由 Barry Warsaw 在gh-98040 中貢獻。）

    要遷移的話請參考以下對應表：

    imp

    importlib

    imp.NullImporter

    將None 插入sys.path_importer_cache

    imp.cache_from_source()

    importlib.util.cache_from_source()

    imp.find_module()

    importlib.util.find_spec()

    imp.get_magic()

    importlib.util.MAGIC_NUMBER

    imp.get_suffixes()

    importlib.machinery.SOURCE_SUFFIXES、importlib.machinery.EXTENSION_SUFFIXES 和importlib.machinery.BYTECODE_SUFFIXES

    imp.get_tag()

    sys.implementation.cache_tag

    imp.load_module()

    importlib.import_module()

    imp.new_module(name)

    types.ModuleType(name)

    imp.reload()

    importlib.reload()

    imp.source_from_cache()

    importlib.util.source_from_cache()

    imp.load_source()

    見下文

    用以下取代imp.load_source()：

    importimportlib.utilimportimportlib.machinerydefload_source(modname,filename):loader=importlib.machinery.SourceFileLoader(modname,filename)spec=importlib.util.spec_from_file_location(modname,filename,loader=loader)module=importlib.util.module_from_spec(spec)# 此模組都會被執行且不會被快取於 sys.modules。# 要快取模組的話可以把下面一行取消註解# sys.modules[module.__name__] = moduleloader.exec_module(module)returnmodule

  • 移除imp 函式和屬性、沒有替代方案：

    • 未以文件記錄的函式：

      • imp.init_builtin()

      • imp.load_compiled()

      • imp.load_dynamic()

      • imp.load_package()

    • imp.lock_held(),imp.acquire_lock(),imp.release_lock():the locking scheme has changed in Python 3.3 to per-module locks.

    • imp.find_module() 常數：SEARCH_ERROR、PY_SOURCE、PY_COMPILED、C_EXTENSION、PY_RESOURCE、PKG_DIRECTORY、C_BUILTIN、PY_FROZEN、PY_CODERESOURCE、IMP_HOOK。

io

  • Removeio'sio.OpenWrapper and_pyio.OpenWrapper, deprecated in Python3.10: just useopen() instead. Theopen() (io.open())function is a built-in function. Since Python 3.10,_pyio.open() isalso a static method.(Contributed by Victor Stinner ingh-94169.)

locale

smtpd

  • 根據PEP 594 的時間表移除smtpd 模組，它在 Python 3.4.7 和 3.5.4 中已被棄用。請改用 PyPI 上的aiosmtpd 模組或任何其他基於asyncio 的伺服器。

sqlite3

  • 以下未以文件記錄的sqlite3 功能已在 Python 3.10 中被棄用、現在已被移除：

    • sqlite3.enable_shared_cache()

    • sqlite3.OptimizedUnicode

    If a shared cache must be used, open the database in URI mode using thecache=shared query parameter.

    Thesqlite3.OptimizedUnicode text factory has been an alias forstr since Python 3.3. Code that previously set the text factory toOptimizedUnicode can either usestr explicitly, or rely on thedefault value which is alsostr.

    （由 Erlend E. Aasland 於gh-92548 中貢獻。）

ssl

  • Removessl'sssl.RAND_pseudo_bytes() function, deprecated in Python 3.6:useos.urandom() orssl.RAND_bytes() instead.(Contributed by Victor Stinner ingh-94199.)

  • Remove thessl.match_hostname() function.It was deprecated in Python 3.7. OpenSSL performshostname matching since Python 3.7, Python no longer uses thessl.match_hostname() function.(Contributed by Victor Stinner ingh-94199.)

  • Remove thessl.wrap_socket() function, deprecated in Python 3.7:instead, create assl.SSLContext object and call itsssl.SSLContext.wrap_socket method. Any package that still usesssl.wrap_socket() is broken and insecure. The function neither sends aSNI TLS extension nor validates the server hostname. Code is subject toCWE 295(Improper Certificate Validation).(Contributed by Victor Stinner ingh-94199.)

unittest

webbrowser

  • Remove support for obsolete browsers fromwebbrowser.The removed browsers include: Grail, Mosaic, Netscape, Galeon, Skipstone,Iceape, Firebird, and Firefox versions 35 and below (gh-102871).

xml.etree.ElementTree

  • Remove theElementTree.Element.copy() method of thepure Python implementation, deprecated in Python 3.10, use thecopy.copy() function instead. The C implementation ofxml.etree.ElementTreehas nocopy() method, only a__copy__() method.(Contributed by Victor Stinner ingh-94383.)

zipimport

  • Removezipimport'sfind_loader() andfind_module() methods,deprecated in Python 3.10: use thefind_spec() method instead. SeePEP 451 for the rationale.(Contributed by Victor Stinner ingh-94379.)

其他

  • Remove thesuspicious rule from the documentationMakefile andDoc/tools/rstlint.py, both in favor ofsphinx-lint.(Contributed by Julien Palard ingh-98179.)

  • Remove thekeyfile andcertfile parameters from theftplib,imaplib,poplib andsmtplib modules,and thekey_file,cert_file andcheck_hostname parameters from thehttp.client module,all deprecated since Python 3.6. Use thecontext parameter(ssl_context inimaplib) instead.(Contributed by Victor Stinner ingh-94172.)

  • 移除數個標準函式庫模組與測試中的Jython 相容性修補程式。（由 Nikita Sobolev 於gh-99482 中貢獻。）

  • 移除ctypes 模組中的_use_broken_old_ctypes_structure_semantics_ 旗標。（由 Nikita Sobolev 於gh-99285 中貢獻。）

移植至 Python 3.12

This section lists previously described changes and other bugfixesthat may require changes to your code.

Python API 的變更

  • More strict rules are now applied for numerical group references andgroup 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 onlycontain ASCII letters and digits and underscore.(Contributed by Serhiy Storchaka ingh-91760.)

  • Removerandrange() functionality deprecated since Python 3.10. Formerly,randrange(10.0) losslessly converted torandrange(10). Now, it raises aTypeError. Also, the exception raised for non-integer values such asrandrange(10.5) orrandrange('10') has been changed fromValueError toTypeError. This also prevents bugs whererandrange(1e25) would silentlyselect from a larger range thanrandrange(10**25).(Originally suggested by Serhiy Storchakagh-86388.)

  • argparse.ArgumentParser changed encoding and error handlerfor reading arguments from file (e.g.fromfile_prefix_chars option)from default text encoding (e.g.locale.getpreferredencoding(False))tofilesystem encoding and error handler.Argument files should be encoded in UTF-8 instead of ANSI Codepage on Windows.

  • Remove theasyncore-basedsmtpd module deprecated in Python 3.4.7and 3.5.4. A recommended replacement is theasyncio-basedaiosmtpd PyPI module.

  • shlex.split(): PassingNone fors argument now raises anexception, rather than readingsys.stdin. The feature was deprecatedin Python 3.9.(Contributed by Victor Stinner ingh-94352.)

  • Theos module no longer accepts bytes-like paths, likebytearray andmemoryview types: only the exactbytes type is accepted for bytes strings.(Contributed by Victor Stinner ingh-98393.)

  • syslog.openlog() andsyslog.closelog() now fail if used in subinterpreters.syslog.syslog() may still be used in subinterpreters,but now only ifsyslog.openlog() has already been called in the main interpreter.These new restrictions do not apply to the main interpreter,so only a very small set of users might be affected.This change helps with interpreter isolation. Furthermore,syslog is a wrapperaround process-global resources, which are best managed from the main interpreter.(Contributed by Donghee Na ingh-99127.)

  • The undocumented locking behavior ofcached_property()is removed, because it locked across all instances of the class, leading to highlock contention. This means that a cached property getter function could now runmore than once for a single instance, if two threads race. For most simplecached properties (e.g. those that are idempotent and simply calculate a valuebased on other attributes of the instance) this will be fine. Ifsynchronization is needed, implement locking within the cached property getterfunction or around multi-threaded access points.

  • sys._current_exceptions() now returns a mapping from thread-id to anexception instance, rather than to a(typ,exc,tb) tuple.(Contributed by Irit Katriel ingh-103176.)

  • When extracting tar files usingtarfile orshutil.unpack_archive(), pass thefilter argument to limit featuresthat may be surprising or dangerous.SeeExtraction filters for details.

  • The output of thetokenize.tokenize() andtokenize.generate_tokens()functions is now changed due to the changes introduced inPEP 701. Thismeans thatSTRING tokens are not emitted any more for f-strings and thetokens described inPEP 701 are now produced instead:FSTRING_START,FSTRING_MIDDLE andFSTRING_END are now emitted for f-string "string"parts in addition to the appropriate tokens for the tokenization in theexpression components. For example for the f-stringf"start{1+1}end"the old version of the tokenizer emitted:

    1,0-1,18:STRING'f"start {1+1} end"'

    while the new version emits:

    1,0-1,2:FSTRING_START'f"'1,2-1,8:FSTRING_MIDDLE'start '1,8-1,9:OP'{'1,9-1,10:NUMBER'1'1,10-1,11:OP'+'1,11-1,12:NUMBER'1'1,12-1,13:OP'}'1,13-1,17:FSTRING_MIDDLE' end'1,17-1,18:FSTRING_END'"'

    Additionally, there may be some minor behavioral changes as a consequence of thechanges required to supportPEP 701. Some of these changes include:

    • Thetype attribute of the tokens emitted when tokenizing some invalid Pythoncharacters such as! has changed fromERRORTOKEN toOP.

    • Incomplete single-line strings now also raisetokenize.TokenError as incompletemultiline strings do.

    • Some incomplete or invalid Python code now raisestokenize.TokenError instead ofreturning arbitraryERRORTOKEN tokens when tokenizing it.

    • Mixing tabs and spaces as indentation in the same file is not supported anymore and willraise aTabError.

  • Thethreading module now expects the_thread module to havean_is_main_interpreter attribute. It is a function with noarguments that returnsTrue if the current interpreter is themain interpreter.

    Any library or application that provides a custom_thread moduleshould provide_is_main_interpreter().(Seegh-112826.)

建置變更

  • Python no longer usessetup.py to build shared C extension modules.Build parameters like headers and libraries are detected inconfigurescript. Extensions are built byMakefile. Most extensions usepkg-config and fall back to manual detection.(Contributed by Christian Heimes ingh-93939.)

  • va_start() with two parameters, likeva_start(args,format),is now required to build Python.va_start() is no longer called with a single parameter.(Contributed by Kumar Aditya ingh-93207.)

  • CPython now uses the ThinLTO option as the default link time optimization policyif the Clang compiler accepts the flag.(Contributed by Donghee Na ingh-89536.)

  • AddCOMPILEALL_OPTS variable inMakefile to overridecompilealloptions (default:-j0) inmakeinstall. Also merged the 3compileall commands into a single command to build .pyc files for alloptimization levels (0, 1, 2) at once.(Contributed by Victor Stinner ingh-99289.)

  • Add platform triplets for 64-bit LoongArch:

    • loongarch64-linux-gnusf

    • loongarch64-linux-gnuf32

    • loongarch64-linux-gnu

    （由 Zhang Na 於gh-90656 中貢獻。）

  • PYTHON_FOR_REGEN 現在需要 Python 3.10 或更新的版本。

  • Autoconf 2.71 and aclocal 1.16.4 is now required to regenerate!configure.(Contributed by Christian Heimes ingh-89886.)

  • Windows builds and macOS installers from python.org now use OpenSSL 3.0.

C API 變更

新增功能

  • PEP 683: IntroduceImmortal Objects, which allows objectsto bypass reference counts, and related changes to the C-API:

    • _Py_IMMORTAL_REFCNT：定義物件的參照計數

      as immortal.

    • _Py_IsImmortal Checks if an object has the immortal reference count.

    • PyObject_HEAD_INIT 這現在將初始化參照計數

      _Py_IMMORTAL_REFCNT（與Py_BUILD_CORE 一起使用時）。

    • SSTATE_INTERNED_IMMORTAL An identifier for interned unicode objects

      that are immortal.

    • SSTATE_INTERNED_IMMORTAL_STATIC An identifier for interned unicode

      objects that are immortal and static

    • sys.getunicodeinternedsize 這會回傳 unicode 的總數

      objects that have been interned. This is now needed forrefleak.py tocorrectly track reference counts and allocated blocks

    （由 Eddie Elizondo 於gh-84436 中貢獻。）

  • PEP 684: Add the newPy_NewInterpreterFromConfig()function andPyInterpreterConfig, which may be usedto create sub-interpreters with their own GILs.(SeePEP 684：直譯器各別持有的 GIL for more info.)(Contributed by Eric Snow ingh-104110.)

  • In the limited C API version 3.12,Py_INCREF() andPy_DECREF() functions are now implemented as opaque function calls tohide implementation details.(Contributed by Victor Stinner ingh-105387.)

移植至 Python 3.12

  • Legacy Unicode APIs based onPy_UNICODE* representation has been removed.Please migrate to APIs based on UTF-8 orwchar_t*.

  • Argument parsing functions likePyArg_ParseTuple() doesn't supportPy_UNICODE* based format (e.g.u,Z) anymore. Please migrateto other formats for Unicode likes,z,es, andU.

  • tp_weaklist for all static builtin types is alwaysNULL.This is an internal-only field onPyTypeObjectbut we're pointing out the change in case someone happens to beaccessing the field directly anyway. To avoid breakage, considerusing the existing public C-API instead, or, if necessary, the(internal-only)_PyObject_GET_WEAKREFS_LISTPTR() macro.

  • This internal-onlyPyTypeObject.tp_subclasses may now not bea valid object pointer. Its type was changed tovoid* toreflect this. We mention this in case someone happens to be accessing theinternal-only field directly.

    To get a list of subclasses, call the Python method__subclasses__() (usingPyObject_CallMethod(),for example).

  • Add support of more formatting options (left aligning, octals, uppercasehexadecimals,intmax_t,ptrdiff_t,wchar_t Cstrings, variable width and precision) inPyUnicode_FromFormat() andPyUnicode_FromFormatV().(Contributed by Serhiy Storchaka ingh-98836.)

  • An unrecognized format character inPyUnicode_FromFormat() andPyUnicode_FromFormatV() now sets aSystemError.In previous versions it caused all the rest of the format string to becopied as-is to the result string, and any extra arguments discarded.(Contributed by Serhiy Storchaka ingh-95781.)

  • Fix wrong sign placement inPyUnicode_FromFormat() andPyUnicode_FromFormatV().(Contributed by Philip Georgi ingh-95504.)

  • Extension classes wanting to add a__dict__ or weak reference slotshould usePy_TPFLAGS_MANAGED_DICT andPy_TPFLAGS_MANAGED_WEAKREF instead oftp_dictoffset andtp_weaklistoffset, respectively.The use oftp_dictoffset andtp_weaklistoffset is stillsupported, but does not fully support multiple inheritance(gh-95589), and performance may be worse.Classes declaringPy_TPFLAGS_MANAGED_DICT must call_PyObject_VisitManagedDict() and_PyObject_ClearManagedDict()to traverse and clear their instance's dictionaries.To clear weakrefs, callPyObject_ClearWeakRefs(), as before.

  • ThePyUnicode_FSDecoder() function no longer accepts bytes-likepaths, likebytearray andmemoryview types: only the exactbytes type is accepted for bytes strings.(Contributed by Victor Stinner ingh-98393.)

  • ThePy_CLEAR,Py_SETREF andPy_XSETREFmacros now only evaluate their arguments once. If an argument has sideeffects, these side effects are no longer duplicated.(Contributed by Victor Stinner ingh-98724.)

  • The interpreter's error indicator is now always normalized. This meansthatPyErr_SetObject(),PyErr_SetString() and the otherfunctions that set the error indicator now normalize the exceptionbefore storing it. (Contributed by Mark Shannon ingh-101578.)

  • _Py_RefTotal is no longer authoritative and only kept aroundfor ABI compatibility. Note that it is an internal global and onlyavailable on debug builds. If you happen to be using it then you'llneed to start using_Py_GetGlobalRefTotal().

  • The following functions now select an appropriate metaclass for the newlycreated type:

    Creating classes whose metaclass overridestp_newis deprecated, and in Python 3.14+ it will be disallowed.Note that these functions ignoretp_new of the metaclass, possiblyallowing incomplete initialization.

    Note thatPyType_FromMetaclass() (added in Python 3.12)already disallows creating classes whose metaclass overridestp_new(__new__() in Python).

    Sincetp_new overrides almost everythingPyType_From* functions do,the two are incompatible with each other.The existing behavior -- ignoring the metaclass for several stepsof type creation -- is unsafe in general, since (meta)classes assume thattp_new was called.There is no simple general workaround. One of the following may work for you:

    • If you control the metaclass, avoid usingtp_new in it:

      • If initialization can be skipped, it can be done intp_init instead.

      • If the metaclass doesn't need to be instantiated from Python,set itstp_new toNULL usingthePy_TPFLAGS_DISALLOW_INSTANTIATION flag.This makes it acceptable forPyType_From* functions.

    • AvoidPyType_From* functions: if you don't need C-specific features(slots or setting the instance size), create types bycallingthe metaclass.

    • If youknow thetp_new can be skipped safely, filter the deprecationwarning out usingwarnings.catch_warnings() from Python.

  • PyOS_InputHook andPyOS_ReadlineFunctionPointer are nolonger called insubinterpreters. This isbecause clients generally rely on process-wide global state (since thesecallbacks have no way of recovering extension module state).

    This also avoids situations where extensions may find themselves running in asubinterpreter that they don't support (or haven't yet been loaded in). Seegh-104668 for more info.

  • PyLongObject has had its internals changed for better performance.Although the internals ofPyLongObject are private, they are usedby some extension modules.The internal fields should no longer be accessed directly, instead the APIfunctions beginningPyLong_... should be used instead.Two newunstable API functions are provided for efficient access to thevalue ofPyLongObjects which fit into a single machine word:

  • Custom allocators, set viaPyMem_SetAllocator(), are nowrequired to be thread-safe, regardless of memory domain. Allocatorsthat don't have their own state, including "hooks", are not affected.If your custom allocator is not already thread-safe and you needguidance then please create a new GitHub issueand CC@ericsnowcurrently.

已棄用

Python 3.14 中待移除的項目

Python 3.15 中待移除的項目

未來版本中的待移除項目

下列 API 已被棄用並將會被移除，不過目前尚未訂定移除日期。

已移除

  • 移除token.h 標頭檔案。從未有任何公開的 tokenizer C API。token.h 標頭檔案的設計是僅限用於 Python 內部。（由 Victor Stinner 於gh-92651 中貢獻。）

  • Legacy Unicode APIs have been removed. SeePEP 623 for detail.

    • PyUnicode_WCHAR_KIND

    • PyUnicode_AS_UNICODE()

    • PyUnicode_AsUnicode()

    • PyUnicode_AsUnicodeAndSize()

    • PyUnicode_AS_DATA()

    • PyUnicode_FromUnicode()

    • PyUnicode_GET_SIZE()

    • PyUnicode_GetSize()

    • PyUnicode_GET_DATA_SIZE()

  • 移除PyUnicode_InternImmortal() 函式巨集。（由 Victor Stinner 於gh-85858 中貢獻。）