# Python 3.13 有什么新变化

编者:

  Thomas Wouters

本文介绍了 Python 3.13 相比 3.12 的新增特性。

完整的详情可参阅 更新日志。

参见

PEP 719 -- Python 3.13 发布计划

备注

预发布版用户应当了解到此文档目前处于草稿状态。 它将随着 Python 3.13 的发步进程不断更新，因此即使已经阅读过较早的版本也仍然值得再次查看。

## 摘要 -- 发布重点

Python 3.13 beta 是 Python 编译语言下一正式版本的预发布版本，包含多项针对语言、实现和标准库的改变。 针对实现的最大改变包括新的交互式解释器，以及对于去除全局解释器锁 ( PEP 703) 和启用即时编译器 ( PEP 744) 的实验性支持。 针对标准库的改变包括移除已弃用的 API 和模块，以及用户友好度和正确性方面的常规改进。

解释器的改进：

- 大幅改进的 交互式解释器 和 改进的错误消息。

- 在新的 交互式解释器 中，以及 回溯信息 和 文档测试 输出中的颜色支持。 这可以通过 `PYTHON_COLORS` and `NO_COLOR` 环境变量来禁用。

- 增加了 PEP 744: 基本的 JIT 编译器。 目前默认是禁用的（但以后可能启用）。 能够小幅度提升性能 -- 我们预计在接下来的几个发布版中不断改进它。

- PEP 667: 现在 `locals()` 内置函数在修改被返回的映射时具有 已定义语义。 Python 调试器及类似的工具现在即使在并发代码执行期间也能更可靠地在已优化的作用域中更新局部变量。

新的类型标注特性：

- PEP 696: 类型形参 (`typing.TypeVar`, `typing.ParamSpec` 和 `typing.TypeVarTuple`) 现在可支持默认值。

- PEP 702: 支持使用新的 `warnings.deprecated()` 装饰器在类型系统中对弃用进行标记。

- PEP 742: 增加了 `typing.TypeIs`，提供更直观的类型细化行为。

- PEP 705: 增加了 `typing.ReadOnly`，用于将 `typing.TypedDict` 的项标记为对类型检查器只读。

自由线程：

- PEP 703: 当使用 `--disable-gil` 编译时 CPython 3.13 将支持在运行时禁用 global interpreter lock。 请参阅 自由线程 CPython 了解详情。

平台支持：

- PEP 730: 现在 Apple 的 iOS 是官方支持的平台。 官方 Official Android 支持 ( PEP 738) 也在计划中。

移除的模块：

- PEP 594: 剩余的 19 个“死电池”已从标准库中移除: `aifc`, `audioop`, `cgi`, `cgitb`, `chunk`, `crypt`, `imghdr`, `mailcap`, `msilib`, `nis`, `nntplib`, `ossaudiodev`, `pipes`, `sndhdr`, `spwd`, `sunau`, `telnetlib`, `uu` 和 `xdrlib`。

- 此外还移除了 `tkinter.tix` 和 `lib2to3` 模块，以及 `2to3` 程序。

发布计划的变化：

- PEP 602 ("Annual Release Cycle for Python") 已更新：

  - Python 3.9 - 3.12 有一年半的完整支持，另加三年半的安全修正。

  - Python 3.13 及以后的版本有两年的完整支持，另加三年的安全修正。

## 新的特性

### 更好的交互式解释器

在类 Unix 系统如 Linux 或 macOS 上以及在 Windows 上，Python 现在将使用新的 interactive shell。 当用户从交互式终端启动 REPL 时这个交互式 shell 现在将支持以下新特性：

- 带颜色的提示符。

- 多行编辑并保留历史记录。

- 使用 `F1` 浏览交互式帮助并带有单独的命令历史。

- 使用 `F2` 浏览去除了输出以及 >>> 和 ... 提示符的历史。

- 使用 `F3` 进入“粘贴模式”以更方便地粘贴大段代码（再次按 `F3` 返回常规提示符）。

- 可以输入 REPL 专属的命令如 `help`, `exit` 和 `quit` 而无需使用在命令名后添加圆括号的调用形式。

如果不想要新的交互式 shell，可以通过 `PYTHON_BASIC_REPL` 环境变量禁用它。

在类 Unix 平台上新的 shell 需要 `curses`。

交互模式的内容详见 交互模式。

（由 Pablo Galindo Salgado, Łukasz Langa 和 Lysandros Nikolaou 在 gh-111201 基于来自 PyPy 项目的代码贡献。 Windows 支持由 Dino Viehland 和 Anthony Shaw 贡献。）

### 改进的错误消息

- 在显示异常回溯时，解释器现在会默认为错误消息着色。这个特性可以用新引入的 `PYTHON_COLORS` 以及经典的 `NO_COLOR` 和 `FORCE_COLOR` 环境变量控制。参见 控制颜色。（由 Pablo Galindo Salgado 在 gh-112730 中贡献。）

- 一个常见错误是撰写的脚本和标准库中的某个模块重名。现在出现此类错误时会显示一条更有用的错误信息：

      $ python random.py
      Traceback (most recent call last):
        File "/home/random.py", line 1, in <module>
          import random; print(random.randint(5))
          ^^^^^^^^^^^^^
        File "/home/random.py", line 1, in <module>
          import random; print(random.randint(5))
                              ^^^^^^^^^^^^^^
      AttributeError: module 'random' has no attribute 'randint' (consider renaming '/home/random.py' since it has the same name as the standard library module named 'random' and the import system gives it precedence)

  类似地，如果一个脚本和它尝试导入的某个第三方模块重名，并且因此产生错误，同样会显示一条更有用的错误信息：

      $ python numpy.py
      Traceback (most recent call last):
        File "/home/numpy.py", line 1, in <module>
          import numpy as np; np.array([1,2,3])
          ^^^^^^^^^^^^^^^^^^
        File "/home/numpy.py", line 1, in <module>
          import numpy as np; np.array([1,2,3])
                              ^^^^^^^^
      AttributeError: module 'numpy' has no attribute 'array' (consider renaming '/home/numpy.py' if it has the same name as a third-party module you intended to import)

  (由 Shantanu Jain 在 gh-95754 中贡献）。

- 往函数传入错误关键字参数时，现在错误信息可能会提示正确的关键字参数。（由 Pablo Galindo Salgado 和 Shantanu Jain 在 gh-107944 中贡献。）

      >>> "better error messages!".split(max_split=1)
      Traceback (most recent call last):
        File "<stdin>", line 1, in <module>
          "better error messages!".split(max_split=1)
          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
      TypeError: split() got an unexpected keyword argument 'max_split'. Did you mean 'maxsplit'?

- 类现在有一个由编译器填充的新属性 `__static_attributes__`，它是一个元组，包含以 `self.X` 形式从类体中定义的任何函数访问的属性。（由 Irit Katriel 在 gh-115775 中贡献）。

### 针对 `locals()` 的已定义修改语义

在历史上，对 `locals()` 的返回值进行修改的预期结果是保留给各个 Python 实现来定义的。

通过 PEP 667，Python 3.13 标准化了 CPython 对于大多数代码执行作用域的历史行为，但也将 已优化作用域 (函数、生成器、协程、推导式和生成器表达式) 修改为显式地返回当前已赋值局部变量的独立快照，包括局部引用的在闭包中捕获的非局部变量。

在已优化的作用域中对 `locals()` 语义的这项修改也会影响隐式地以 `locals()` 为目标的代码执行函数的默认行为，如果没有提供显式命名空间的话（例如 `exec()` 和 `eval()` 等）。 在之前的版本中，在调用代码执行函数后是否可以通过调用 `locals()` 访问更改情况取决于具体的实现。 具体到 CPython 而言，此类代码通常会按预期运作，但有时可能会在基于其他代码（包括调试器和代码执行跟踪工具）的已优化作用域中失败，因为代码有可能重置该作用域中的共享快照。 现在，代码在已优化作用域中将始终针对局部变量的独立快照运行，因此在后续调用 `locals()` 时将永远看不到更改。 要访问在这些情况下所做的更改，现在必须将一个显式命名空间引用传递给相关的函数。 或者，也可以更新受影响的代码以使用更高级别的代码执行 API 返回结果代码执行命名空间 （例如，当执行磁盘上的 Python 文件时使用 `runpy.run_path()` 函数）。

为确保调试器和类似工具能可靠地更新受到此变化影响的作用域中的局部变量，现在 `FrameType.f_locals` 将返回一个针对此种作用域中的帧的局部变量和在局部引用的非局部变量的直通写入代理对象，而不是返回一个非持续更新的具有未定义的运行时语义的共享 `dict` 实例。

请参阅 PEP 667 了解详情，包括相关的 C API 更改和弃用。 下文还针对受影响的 Python API 和 C API 提供了移植说明。

（PEP 和实现由 Mark Shannon 和 Tian Gao 在 gh-74929 中贡献。 文档更新由 Guido van Rossum 和 Alyssa Coghlan 提供。）

### 增量式垃圾回收

- 循环垃圾回收器现在是增量式的。这意味着对更大的堆进行垃圾收集的最大暂停时间会减小一个数量级以上。

### 对移动平台的支持

- 现在 iOS 是 PEP 11 支持的平台。 `arm64-apple-ios` (2013 年之后发布的 iPhone 和 iPad 设备) 和 `arm64-apple-ios-simulator` (运行于 Apple Silicon 硬件之上的 Xcode iOS 模拟器) 现在是第 3 层级的平台。

  `x86_64-apple-ios-simulator` (运行于较老的 x86_64 硬件之上的 Xcode iOS) 不是第 3 层级的受支持平台，但将会尽可能地提供支持。

  请参阅 PEP 730 了解详情。

  （PEP 的撰写和实现由 Russell Keith-Magee 在 gh-114099 中贡献。）

## 实验性的 JIT 编译器

使用 `--enable-experimental-jit` 选项配置 CPython 时，会添加一个可以让部分 Python 程序提升速度的即时编译器。

其内部架构大致如下。

- 我们将从特化的 第 1 层级字节码 开始。 请参阅 3.11 有什么新变化 了解详情。

- 当第 1 层级字节码达到足够热度，它将被翻译为新的、纯内部的 第 2 层级 IR，即微操作码 ("uops")。

- 第 2 层级 IR 使用同一个基于栈的 VM 作为第 1 层级，但其指令格式更适合被翻译为机器码。

- 在第 2 层级 IR 被解释或翻译为机器码之前，我们会预先应用一些优化通路。

- 虽然第 2 层级解释器存在，但它主要用于对优化管线的先前阶段进行调试。可通过为 Python 配置 `--enable-experimental-jit=interpreter` 选项启用第 2 层级解释器。

- 启用 JIT 时，经优化的第 2 层级 IR 将被翻译为机器码后再执行。

- 这个机器码翻译过程使用了名为 拷贝并打补丁 的技巧。 它没有运行时依赖，但增加了构建时对 LLVM 的依赖。

`--enable-experimental-jit` 旗标具有下列可选值：

- `no` (默认值) -- 禁用整个第 2 层级和 JIT 管线。

- `yes` (当提供了该旗标但没有可选值时的默认值) -- 启用 JIT。 要在运行时禁用 JIT，请传入环境变量 `PYTHON_JIT=0`。

- `yes-off` -- 构建 JIT 但默认禁用它。要在运行时启用 JIT，请传入环境变量 `PYTHON_JIT=1`。

- `interpreter` -- 启用第 2 层级解释器，但是禁用 JIT。运行时传入 `PYTHON_JIT=0` 可以禁用解释器。

（在 Windows 上，使用 `PCbuild/build.bat --experimental-jit` 启用 JIT，使用 `--experimental-jit-interpreter` 启用第 2 层级解释器。）

详见 PEP 744。

（JIT 来自 Brandt Bucher 且受到 Haoran Xu 和 Fredrik Kjolstad 论文的启发。第 2 层级 IR 来自 Mark Shannon 和 Guido van Rossum。第 2 层级解释器来自 Ken Jin。）

## 自由线程的 CPython

在使用 `--disable-gil` 选项配置进行构建时，CPython 将在运行时禁用 global interpreter lock (GIL)。 这是一个实验性特性，因此默认将不使用。 用户需要编译自己的解释器，或者安装标记为 free-threaded 的实验性构建版。 请参阅 PEP 703 "Making the Global Interpreter Lock Optional in CPython" 了解详情。

自由线程允许通过在可用的 CPU 核心上并行运行线程来充分地利用可用的处理能力。虽然并非所有软件都会自动受益于此，但考虑到多线程设计的程序将在多核硬件上运行地更快。

工作仍在进行中：预计会出现一些错误和显著的单线程性能损失。

自由线程构建仍然支持在运行时使用环境变量 `PYTHON_GIL` 或命令行选项 `-X gil` 选择性地启用 GIL。

要检查当前解释器是否配置了 `--disable-gil`，请使用 `sysconfig.get_config_var("Py_GIL_DISABLED")`。要检查 GIL 是否在正在运行的进程中实际被禁用，可以使用 `sys._is_gil_enabled()` 函数。

C-API 扩展模块需要专门为自由线程构建而构建。支持在禁用 GIL 的情况下运行的扩展应使用 `Py_mod_gil` 插槽。使用单阶段初始化的扩展应使用 `PyUnstable_Module_SetGIL()` 来指示它们是否支持在禁用 GIL 的情况下运行。导入不使用这些机制的 C 扩展将导致启用 GIL，除非使用 `PYTHON_GIL` 环境变量或 `-X gil=0` 选项明确禁用 GIL。

需要 pip 24.1b1 或更新版本才能在自由线程构建中安装带有 C 扩展的包。

## 其他语言特性修改

- 允许 `str.replace()` 的 count 参数为关键字参数。 （由 Hugo van Kemenade 在 gh-106487 中贡献。）

- 编译器现在会删除文档字符串中的缩进。 这将减少 字节码缓存 (即 `.pyc` 文件) 的大小。例如，SQLAlchemy 2.0 中 `sqlalchemy.orm.session` 的缓存文件大小减少了约 5%。 此更改将影响使用文档字符串的工具，例如 `doctest`。 （由 Inada Naoki 在 gh-81283 中贡献。）

- `compile()` 内置函数现在可以接受新的旗标 `ast.PyCF_OPTIMIZED_AST`，它与 `ast.PyCF_ONLY_AST` 类似，不同之处在于返回的 `AST` 是根据 `optimize` 参数的值进行优化的。（由 Irit Katriel 在 gh-108113 中贡献）。

- `multiprocessing`、`concurrent.futures`、`compileall`：将 `os.cpu_count()` 替换为 `os.process_cpu_count()`，以选择默认的工作线程和进程数。如果支持，则获取 CPU 亲和性。（由 Victor Stinner 在 gh-109649 中贡献。）

- 即使文件不可访问，`os.path.realpath()` 现在也能解析 MS-DOS 样式的文件名。（由 Moonsik Park 在 gh-82367 中贡献。）

- 修复了当在 `else` 块中使用全局变量时 `except` 块中的 `global` 声明被拒绝的错误。（由 Irit Katriel 在 gh-111123 中贡献。）

- 现在许多函数会对将布尔值作为文件描述符参数发出警告。这可以帮助尽早发现一些错误。（由 Serhiy Storchaka 在 gh-82626 中贡献。）

- 添加了新的环境变量 `PYTHON_FROZEN_MODULES`。它决定导入机制是否忽略冻结模块，相当于 `-X frozen_modules` 命令行选项。（由 Yilei Yang 在 gh-111374 中贡献。）

- 添加无需帧指针即可工作的 性能分析器支持，可通过新的环境变量 `PYTHON_PERF_JIT_SUPPORT` 和命令行选项 `-X perf_jit <-X>`启用（由 Pablo Galindo 在 :gh:`118518` 中贡献。）

- 新的 `PYTHON_HISTORY` 环境变量可用于更改 `.python_history` 文件的位置。（由 Levi Sabah、Zackery Spytz 和 Hugo van Kemenade 在 gh-73965 中贡献。）

- 添加 `PythonFinalizationError` 异常。当操作在 解释器关闭 期间被阻止时，会抛出此派生自 `RuntimeError` 的异常。

  下列函数现在会引发 PythonFinalizationError，而不是 `RuntimeError`:

  - `_thread.start_new_thread()`。

  - `subprocess.Popen`。

  - `os.fork()`。

  - `os.forkpty()`。

  （由 Victor Stinner 在 gh-114570 中贡献。）

- 为 `bz2`, `lzma`, `tarfile` 和 `zipfile` 等模块中的已压缩和已归档文件型对象添加了 `name` 和 `mode` 属性。 （由 Serhiy Storchaka 在 gh-115961 中贡献。）

- 通过添加五个新方法来允许控制 Expat >=2.6.0 重解析延迟 (CVE-2023-52425)：

  - `xml.etree.ElementTree.XMLParser.flush()`

  - `xml.etree.ElementTree.XMLPullParser.flush()`

  - `xml.parsers.expat.xmlparser.GetReparseDeferralEnabled()`

  - `xml.parsers.expat.xmlparser.SetReparseDeferralEnabled()`

  - `xml.sax.expatreader.ExpatParser.flush()`

  （由 Sebastian Pipping 在 gh-115623 中贡献。）

- `ssl.create_default_context()` API 现在默认包含 `ssl.VERIFY_X509_PARTIAL_CHAIN` 和 `ssl.VERIFY_X509_STRICT` 旗标。

  备注

  `ssl.VERIFY_X509_STRICT` 可能会拒绝底层 OpenSSL 实现本来会接受的 RFC 5280 之前的证书或格式错误的证书。虽然不建议禁用此功能，但您可以使用以下方法禁用：

      ctx = ssl.create_default_context()
      ctx.verify_flags &= ~ssl.VERIFY_X509_STRICT

  （由 William Woodruff 在 gh-112389 贡献。）

- `configparser.ConfigParser` 现在可以被配置为在命名部分之前接受未命名部分。（由 Pedro Sousa Lacerda 在 gh-66449 中贡献。）

- 类作用域内的 标注作用域 现在可以包含 lambda 和推导式。位于类范围内的推导式不会内联到其父作用域中。（由 Jelle Zijlstra 在 gh-109118 和 gh-118160 中贡献。）

- 类有一个新的 `__firstlineno__` 属性，由编译器填充，其中包含类定义第一行的行号。（由 Serhiy Storchaka 在 gh-118465 中贡献。）

- 现在如果模块名前有点，`from __future__ import ...` 语句只是普通的相对导入。（由 Jeremiah Gabriel Pascual 在 gh-118216 中贡献。）

## 新增模块

- 无。

## 改进的模块

### argparse

- 为 `add_argument()` 和 `add_parser()` 方法添加了形参 deprecated 以允许弃用命令行选项、位置参数和子命令。 （由 Serhiy Storchaka 在 gh-83648 中贡献。）

### array

- 增加了 `'w'` 类型码 (`Py_UCS4`)，它可被用于 Unicode 字符串。 它可被用来代替已弃用的 `'u'` 类型码。 （由 Inada Naoki 在 gh-80480 中贡献。）

- 增加了 `clear()` 方法以实现 `MutableSequence`。 （由 Mike Zimin 在 gh-114894 中贡献。）

### ast

- 现在 `ast` 模块中节点类型的构造器对其可接受的参数要求更严格，并在参数被省略时具有更易理解的行为。

  If an optional field on an AST node is not included as an argument when constructing an instance, the field will now be set to `None`. Similarly, if a list field is omitted, that field will now be set to an empty list, and if a `ast.expr_context` field is omitted, it defaults to `Load()`. (Previously, in all cases, the attribute would be missing on the newly constructed AST node instance.)

  If other arguments are omitted, a `DeprecationWarning` is emitted. This will cause an exception in Python 3.15. Similarly, passing a keyword argument that does not map to a field on the AST node is now deprecated, and will raise an exception in Python 3.15.

  These changes do not apply to user-defined subclasses of `ast.AST`, unless the class opts in to the new behavior by setting the attribute `ast.AST._field_types`.

  (Contributed by Jelle Zijlstra in gh-105858, gh-117486, and gh-118851.)

- `ast.parse()` now accepts an optional argument optimize which is passed on to the `compile()` built-in. This makes it possible to obtain an optimized AST. (Contributed by Irit Katriel in gh-108113.)

### asyncio

- `asyncio.loop.create_unix_server()` will now automatically remove the Unix socket when the server is closed. (Contributed by Pierre Ossman in gh-111246.)

- `asyncio.DatagramTransport.sendto()` will now send zero-length datagrams if called with an empty bytes object. The transport flow control also now accounts for the datagram header when calculating the buffer size. (Contributed by Jamie Phan in gh-115199.)

- Add `asyncio.Server.close_clients()` and `asyncio.Server.abort_clients()` methods which allow to more forcefully close an asyncio server. (Contributed by Pierre Ossman in gh-113538.)

- `asyncio.as_completed()` now returns an object that is both an asynchronous iterator and a plain iterator of awaitables. The awaitables yielded by asynchronous iteration include original task or future objects that were passed in, making it easier to associate results with the tasks being completed. (Contributed by Justin Arthur in gh-77714.)

- When `asyncio.TaskGroup.create_task()` is called on an inactive `asyncio.TaskGroup`, the given coroutine will be closed (which prevents a `RuntimeWarning` about the given coroutine being never awaited). (Contributed by Arthur Tacca and Jason Zhang in gh-115957.)

- Improved behavior of `asyncio.TaskGroup` when an external cancellation collides with an internal cancellation. For example, when two task groups are nested and both experience an exception in a child task simultaneously, it was possible that the outer task group would hang, because its internal cancellation was swallowed by the inner task group.

  In the case where a task group is cancelled externally and also must raise an `ExceptionGroup`, it will now call the parent task's `cancel()` method. This ensures that a `asyncio.CancelledError` will be raised at the next `await`, so the cancellation is not lost.

  An added benefit of these changes is that task groups now preserve the cancellation count (`asyncio.Task.cancelling()`).

  In order to handle some corner cases, `asyncio.Task.uncancel()` may now reset the undocumented `_must_cancel` flag when the cancellation count reaches zero.

  (Inspired by an issue reported by Arthur Tacca in gh-116720.)

- Add `asyncio.Queue.shutdown()` (along with `asyncio.QueueShutDown`) for queue termination. (Contributed by Laurie Opperman and Yves Duprat in gh-104228.)

- 在 `asyncio.StreamReader.readuntil()` 中接受一个由分隔符组成的元组，当遇到其中之一时将停止。 （由 Bruce Merry 在 gh-81322 中贡献。）

### base64

- Add `base64.z85encode()` and `base64.z85decode()` functions which allow encoding and decoding Z85 data. See Z85 specification for more information. (Contributed by Matan Perelman in gh-75299.)

### copy

- Add `copy.replace()` function which allows to create a modified copy of an object, which is especially useful for immutable objects. It supports named tuples created with the factory function `collections.namedtuple()`, `dataclass` instances, various `datetime` objects, `Signature` objects, `Parameter` objects, code object, and any user classes which define the `__replace__()` method. (Contributed by Serhiy Storchaka in gh-108751.)

### ctypes

- The layout of bit fields in `Structure` and `Union` was improved to better match platform defaults (GCC/Clang or MSC). In particular, fields no longer overlap. (Contributed by Matthias Görgens in gh-97702.)

- A `ctypes.Structure._layout_` class attribute can be set to help match a non-default ABI. (Contributed by Petr Viktorin in gh-97702.)

### dbm

- Add `dbm.gnu.gdbm.clear()` and `dbm.ndbm.ndbm.clear()` methods that remove all items from the database. (Contributed by Donghee Na in gh-107122.)

- Add new `dbm.sqlite3` backend, and make it the default `dbm` backend. (Contributed by Raymond Hettinger and Erlend E. Aasland in gh-100414.)

### dis

- Change the output of `dis` module functions to show logical labels for jump targets and exception handlers, rather than offsets. The offsets can be added with the new `-O` command line option or the `show_offsets` parameter. (Contributed by Irit Katriel in gh-112137.)

- `get_instructions()` no longer represents cache entries as separate instructions. Instead, it returns them as part of the `Instruction`, in the new cache_info field. The show_caches argument to `get_instructions()` is deprecated and no longer has any effect. (Contributed by Irit Katriel in gh-112962.)

### doctest

- Color is added to the output by default. This can be controlled via the new `PYTHON_COLORS` environment variable as well as the canonical `NO_COLOR` and `FORCE_COLOR` environment variables. See also 控制颜色. (Contributed by Hugo van Kemenade in gh-117225.)

- The `doctest.DocTestRunner.run()` method now counts the number of skipped tests. Add `doctest.DocTestRunner.skips` and `doctest.TestResults.skipped` attributes. (Contributed by Victor Stinner in gh-108794.)

### email

- `email.utils.getaddresses()` and `email.utils.parseaddr()` now return `('', '')` 2-tuples in more situations where invalid email addresses are encountered instead of potentially inaccurate values. Add optional strict parameter to these two functions: use `strict=False` to get the old behavior, accept malformed inputs. `getattr(email.utils, 'supports_strict_parsing', False)` can be used to check if the strict parameter is available. (Contributed by Thomas Dwyer and Victor Stinner for gh-102988 to improve the CVE-2023-27043 fix.)

### fractions

- Formatting for objects of type `fractions.Fraction` now supports the standard format specification mini-language rules for fill, alignment, sign handling, minimum width and grouping. (Contributed by Mark Dickinson in gh-111320.)

### gc

- The cyclic garbage collector is now incremental, which changes the meanings of the results of `gc.get_threshold()` and `gc.set_threshold()` as well as `gc.get_count()` and `gc.get_stats()`.

  - `gc.get_threshold()` returns a three-item tuple for backwards compatibility. The first value is the threshold for young collections, as before; the second value determines the rate at which the old collection is scanned (the default is 10, and higher values mean that the old collection is scanned more slowly). The third value is meaningless and is always zero.

  - `gc.set_threshold()` ignores any items after the second.

  - `gc.get_count()` and `gc.get_stats()` return the same format of results as before. The only difference is that instead of the results referring to the young, aging and old generations, the results refer to the young generation and the aging and collecting spaces of the old generation.

  In summary, code that attempted to manipulate the behavior of the cycle GC may not work exactly as intended, but it is very unlikely to be harmful. All other code will work just fine.

### glob

- Add `glob.translate()` function that converts a path specification with shell-style wildcards to a regular expression. (Contributed by Barney Gale in gh-72904.)

### importlib

- Previously deprecated `importlib.resources` functions are un-deprecated:

  > - `is_resource()`

  > - `open_binary()`

  > - `open_text()`

  > - `path()`

  > - `read_binary()`

  > - `read_text()`

  All now allow for a directory (or tree) of resources, using multiple positional arguments.

  For text-reading functions, the encoding and errors must now be given as keyword arguments.

  The `contents()` remains deprecated in favor of the full-featured `Traversable` API. However, there is now no plan to remove it.

  (Contributed by Petr Viktorin in gh-106532.)

### 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_mapped` property, which returns the IPv4-mapped IPv6 address. (Contributed by Charles Machalow in gh-109466.)

- Fix `is_global` and `is_private` behavior in `IPv4Address`, `IPv6Address`, `IPv4Network` and `IPv6Network`.

### itertools

- Added a `strict` option to `itertools.batched()`. This raises a `ValueError` if the final batch is shorter than the specified batch size. (Contributed by Raymond Hettinger in gh-113202.)

### marshal

- Add the allow_code parameter in module functions. Passing `allow_code=False` prevents serialization and de-serialization of code objects which are incompatible between Python versions. (Contributed by Serhiy Storchaka in gh-113626.)

### math

- A new function `fma()` for fused multiply-add operations has been added. This function computes `x * y + z` with only a single round, and so avoids any intermediate loss of precision. It wraps the `fma()` function provided by C99, and follows the specification of the IEEE 754 "fusedMultiplyAdd" operation for special cases. (Contributed by Mark Dickinson and Victor Stinner in gh-73468.)

### mimetypes

- Add the `guess_file_type()` function which works with file path. Passing file path instead of URL in `guess_type()` is soft deprecated. (Contributed by Serhiy Storchaka in gh-66543.)

### mmap

- The `mmap.mmap` class now has an `seekable()` method that can be used when a seekable file-like object is required. The `seek()` method now returns the new absolute position. (Contributed by Donghee Na and Sylvie Liberman in gh-111835.)

- `mmap.mmap` now has a trackfd parameter on Unix; if it is `False`, the file descriptor specified by fileno will not be duplicated. (Contributed by Zackery Spytz and Petr Viktorin in gh-78502.)

- `mmap.mmap` is now protected from crashing on Windows when the mapped memory is inaccessible due to file system errors or access violations. (Contributed by Jannis Weigend in gh-118209.)

### opcode

- Move `opcode.ENABLE_SPECIALIZATION` to `_opcode.ENABLE_SPECIALIZATION`. This field was added in 3.12, it was never documented and is not intended for external usage. (Contributed by Irit Katriel in gh-105481.)

- Removed `opcode.is_pseudo`, `opcode.MIN_PSEUDO_OPCODE` and `opcode.MAX_PSEUDO_OPCODE`, which were added in 3.12, were never documented or exposed through `dis`, 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()`, and `os.timerfd_gettime_ns()`, `os.TFD_NONBLOCK`, `os.TFD_CLOEXEC`, `os.TFD_TIMER_ABSTIME`, and `os.TFD_TIMER_CANCEL_ON_SET` (Contributed by Masaru Tsuchiyama in gh-108277.)

- `os.cpu_count()` and `os.process_cpu_count()` can be overridden through the new environment variable `PYTHON_CPU_COUNT` or the new command-line option `-X cpu_count`. This option is useful for users who need to limit CPU resources of a container system without having to modify the container (application code). (Contributed by Donghee Na in gh-109595.)

- Add support of `os.lchmod()` and the follow_symlinks argument in `os.chmod()` on Windows. Note that the default value of follow_symlinks in `os.lchmod()` is `False` on Windows. (Contributed by Serhiy Storchaka in gh-59616.)

- Add support of `os.fchmod()` and a file descriptor in `os.chmod()` on Windows. (Contributed by Serhiy Storchaka in gh-113191.)

- `os.posix_spawn()` now accepts `env=None`, which makes the newly spawned process use the current process environment. (Contributed by Jakub Kulik in gh-113119.)

- `os.posix_spawn()` gains an `os.POSIX_SPAWN_CLOSEFROM` attribute for use in `file_actions=` on platforms that support `posix_spawn_file_actions_addclosefrom_np()`. (Contributed by Jakub Kulik in gh-113117.)

- `os.mkdir()` and `os.makedirs()` on Windows now support passing a mode value of `0o700` to apply access control to the new directory. This implicitly affects `tempfile.mkdtemp()` and is a mitigation for CVE-2024-4030. Other values for mode continue to be ignored. (Contributed by Steve Dower in gh-118486.)

### os.path

- Add `os.path.isreserved()` to check if a path is reserved on the current system. This function is only available on Windows. (Contributed by Barney Gale in gh-88569.)

- On Windows, `os.path.isabs()` no longer considers paths starting with exactly one (back)slash to be absolute. (Contributed by Barney Gale and Jon Foster in gh-44626.)

- Add support of dir_fd and follow_symlinks keyword arguments in `shutil.chown()`. (Contributed by Berker Peksag and Tahia K in gh-62308)

### pathlib

- Add `pathlib.UnsupportedOperation`, which is raised instead of `NotImplementedError` when a path operation isn't supported. (Contributed by Barney Gale in gh-89812.)

- Add `pathlib.Path.from_uri()`, a new constructor to create a `pathlib.Path` object from a 'file' URI (`file://`). (Contributed by Barney Gale in gh-107465.)

- Add `pathlib.PurePath.full_match()` for matching paths with shell-style wildcards, including the recursive wildcard "`**`". (Contributed by Barney Gale in gh-73435.)

- Add `pathlib.PurePath.parser` class attribute that stores the implementation of `os.path` used for low-level path parsing and joining: either `posixpath` or `ntpath`.

- Add recurse_symlinks keyword-only argument to `pathlib.Path.glob()` and `rglob()`. (Contributed by Barney Gale in gh-77609.)

- Add follow_symlinks keyword-only argument to `is_file()`, `is_dir()`, `owner()`, `group()`. (Contributed by Barney Gale in gh-105793, and Kamil Turek in gh-107962.)

- Return files and directories from `pathlib.Path.glob()` and `rglob()` when given a pattern that ends with "`**`". In earlier versions, only directories were returned. (Contributed by Barney Gale in gh-70303.)

### pdb

- Add ability to move between chained exceptions during post mortem debugging in `pm()` using the new `exceptions [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 when `sys.flags.safe_path` is set (via the `-P` command line option or `PYTHONSAFEPATH` environment variable). (Contributed by Tian Gao and Christian Walther in gh-111762.)

- `zipapp` is supported as a debugging target. (Contributed by Tian Gao in gh-118501.)

- `breakpoint()` and `pdb.set_trace()` now enter the debugger immediately rather than on the next line of code to be executed. This change prevents the debugger from breaking outside of the context when `breakpoint()` is positioned at the end of the context. (Contributed by Tian Gao in gh-118579.)

### queue

- Add `queue.Queue.shutdown()` (along with `queue.ShutDown`) for queue termination. (Contributed by Laurie Opperman and Yves Duprat in gh-104750.)

### random

- Add a command-line interface. (Contributed by Hugo van Kemenade in gh-118131.)

### re

- Rename `re.error` to `re.PatternError` for improved clarity. `re.error` is kept for backward compatibility.

### site

- `.pth` files are now decoded by UTF-8 first, and then by the locale encoding if the UTF-8 decoding fails. (Contributed by Inada Naoki in gh-117802.)

### sqlite3

- A `ResourceWarning` is now emitted if a `sqlite3.Connection` object is not `closed` explicitly. (Contributed by Erlend E. Aasland in gh-105539.)

- Add filter keyword-only parameter to `sqlite3.Connection.iterdump()` for filtering database objects to dump. (Contributed by Mariusz Felisiak in gh-91602.)

### statistics

- Add `statistics.kde()` for kernel density estimation. This makes it possible to estimate a continuous probability density function from a fixed number of discrete samples. Also added `statistics.kde_random()` for sampling from the estimated probability density function. (Contributed by Raymond Hettinger in gh-115863.)

### subprocess

- The `subprocess` module now uses the `os.posix_spawn()` function in more situations. Notably in the default case of `close_fds=True` on more recent versions of platforms including Linux, FreeBSD, and Solaris where the C library provides `posix_spawn_file_actions_addclosefrom_np()`. On Linux this should perform similar to our existing Linux `vfork()` based code. A private control knob `subprocess._USE_POSIX_SPAWN` can be set to `False` if you need to force `subprocess` not to ever use `os.posix_spawn()`. Please report your reason and platform details in the CPython issue tracker if you set this so that we can improve our API selection logic for everyone. (Contributed by Jakub Kulik in gh-113117.)

### sys

- Add the `sys._is_interned()` function to test if the string was interned. This function is not guaranteed to exist in all implementations of Python. (Contributed by Serhiy Storchaka in gh-78573.)

### tempfile

- On Windows, the default mode `0o700` used by `tempfile.mkdtemp()` now limits access to the new directory due to changes to `os.mkdir()`. This is a mitigation for CVE-2024-4030. (Contributed by Steve Dower in gh-118486.)

### time

- On Windows, `time.monotonic()` now uses the `QueryPerformanceCounter()` clock to have a resolution better than 1 us, instead of the `GetTickCount64()` clock which has a resolution of 15.6 ms. (Contributed by Victor Stinner in gh-88494.)

- On Windows, `time.time()` now uses the `GetSystemTimePreciseAsFileTime()` clock to have a resolution better than 1 μs, instead of the `GetSystemTimeAsFileTime()` clock which has a resolution of 15.6 ms. (Contributed by Victor Stinner in gh-63207.)

### tkinter

- Add `tkinter` widget methods: `tk_busy_hold()`, `tk_busy_configure()`, `tk_busy_cget()`, `tk_busy_forget()`, `tk_busy_current()`, and `tk_busy_status()`. (Contributed by Miguel, klappnase and Serhiy Storchaka in gh-72684.)

- The `tkinter` widget method `wm_attributes()` now accepts the attribute name without the minus prefix to get window attributes, e.g. `w.wm_attributes('alpha')` and allows to specify attributes and values to set as keyword arguments, e.g. `w.wm_attributes(alpha=0.5)`. Add new optional keyword-only parameter return_python_dict: calling `w.wm_attributes(return_python_dict=True)` returns the attributes as a dict instead of a tuple. (Contributed by Serhiy Storchaka in gh-43457.)

- Add new optional keyword-only parameter return_ints in the `Text.count()` method. Passing `return_ints=True` makes it always returning the single count as an integer instead of a 1-tuple or `None`. (Contributed by Serhiy Storchaka in gh-97928.)

- Add support of the "vsapi" element type in the `element_create()` method of `tkinter.ttk.Style`. (Contributed by Serhiy Storchaka in gh-68166.)

- Add the `after_info()` method for Tkinter widgets. (Contributed by Cheryl Sabella in gh-77020.)

- Add the `PhotoImage` method `copy_replace()` to copy a region from one image to other image, possibly with pixel zooming and/or subsampling. Add from_coords parameter to `PhotoImage` methods `copy()`, `zoom()` and `subsample()`. Add zoom and subsample parameters to `PhotoImage` method `copy()`. (Contributed by Serhiy Storchaka in gh-118225.)

- Add the `PhotoImage` methods `read()` to read an image from a file and `data()` to get the image data. Add background and grayscale parameters to `PhotoImage` method `write()`. (Contributed by Serhiy Storchaka in gh-118271.)

### 回溯

- Add show_group parameter to `traceback.TracebackException.format_exception_only()` to format the nested exceptions of a `BaseExceptionGroup` instance, recursively. (Contributed by Irit Katriel in gh-105292.)

- Add the field exc_type_str to `TracebackException`, which holds a string display of the exc_type. Deprecate the field exc_type which holds the type object itself. Add parameter save_exc_type (default `True`) to indicate whether `exc_type` should be saved. (Contributed by Irit Katriel in gh-112332.)

### types

- `SimpleNamespace` constructor now allows specifying initial values of attributes as a positional argument which must be a mapping or an iterable of key-value pairs. (Contributed by Serhiy Storchaka in gh-108191.)

### typing

- Add `typing.get_protocol_members()` to return the set of members defining a `typing.Protocol`. Add `typing.is_protocol()` to check whether a class is a `typing.Protocol`. (Contributed by Jelle Zijlstra in gh-104873.)

- Add `typing.ReadOnly`, a special typing construct to mark an item of a `typing.TypedDict` as read-only for type checkers. See PEP 705 for more details.

- Add `typing.NoDefault`, a sentinel object used to represent the defaults of some parameters in the `typing` module. (Contributed by Jelle Zijlstra in gh-116126.)

### unicodedata

- The Unicode database has been updated to version 15.1.0. (Contributed by James Gerity in gh-109559.)

### venv

- Add support for adding source control management (SCM) ignore files to a virtual environment's directory. By default, Git is supported. This is implemented as opt-in via the API which can be extended to support other SCMs (`venv.EnvBuilder` and `venv.create()`), and opt-out via the CLI (using `--without-scm-ignore-files`). (Contributed by Brett Cannon in gh-108125.)

### warnings

- The new `warnings.deprecated()` decorator provides a way to communicate deprecations to static type checkers and to warn on usage of deprecated classes and functions. A runtime deprecation warning may also be emitted when a decorated function or class is used at runtime. See PEP 702. (Contributed by Jelle Zijlstra in gh-104003.)

### xml.etree.ElementTree

- Add the `close()` method for the iterator returned by `iterparse()` for explicit cleaning up. (Contributed by Serhiy Storchaka in gh-69893.)

### zipimport

- Gains support for ZIP64 format files. Everybody loves huge code right? (Contributed by Tim Hatch in gh-94146.)

## 性能优化

- `textwrap.indent()` is now ~30% faster than before for large input. (Contributed by Inada Naoki in gh-107369.)

- The `subprocess` module uses `os.posix_spawn()` in more situations including the default where `close_fds=True` on many modern platforms. This should provide a noteworthy performance increase launching processes on FreeBSD and Solaris. See the subprocess section above for details. (Contributed by Jakub Kulik in gh-113117.)

- Several standard library modules have had their import times significantly improved. For example, the import time of the `typing` module has been reduced by around a third by removing dependencies on `re` and `contextlib`. Other modules to enjoy import-time speedups include `importlib.metadata`, `threading`, `enum`, `functools` and `email.utils`. (Contributed by Alex Waygood, Shantanu Jain, Adam Turner, Daniel Hollas and others in gh-109653.)

## 被移除的模块与 API

### PEP 594: 死电池（与其他模块移除）

- PEP 594 从标准库移除了 19 个从 Python 3.11 起弃用的模块：

  - `aifc`. (Contributed by Victor Stinner in gh-104773.)

  - `audioop`. (Contributed by Victor Stinner in gh-104773.)

  - `chunk`. (Contributed by Victor Stinner in gh-104773.)

  - `cgi` and `cgitb`.

    - `cgi.FieldStorage` can typically be replaced with `urllib.parse.parse_qsl()` for `GET` and `HEAD` requests, and the `email.message` module or multipart PyPI project for `POST` and `PUT`.

    - `cgi.parse()` can be replaced by calling `urllib.parse.parse_qs()` directly on the desired query string, except for `multipart/form-data` input, which can be handled as described for `cgi.parse_multipart()`.

    - `cgi.parse_header()` can be replaced with the functionality in the `email` package, which implements the same MIME RFCs. For example, with `email.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 the `email` package (e.g. `email.message.EmailMessage` and `email.message.Message`) which implements the same MIME RFCs, or with the multipart PyPI project.

    (Contributed by Victor Stinner in gh-104773.)

  - `crypt` module and its private `_crypt` extension. The `hashlib` module is a potential replacement for certain use cases. Otherwise, the following PyPI projects can be used:

    - bcrypt: Modern password hashing for your software and your servers.

    - passlib: Comprehensive password hashing framework supporting over 30 schemes.

    - argon2-cffi: The secure Argon2 password hashing algorithm.

    - legacycrypt: `ctypes` wrapper to the POSIX crypt library call and associated functionality.

    - crypt_r: Fork of the `crypt` module, wrapper to the crypt_r(3) library call and associated functionality.

    (Contributed by Victor Stinner in gh-104773.)

  - `imghdr`: use the projects filetype, puremagic, or python-magic instead. The `puremagic.what()` function can be used to replace the `imghdr.what()` function for all file formats that were supported by `imghdr`. (Contributed by Victor Stinner in gh-104773.)

  - `mailcap`. The `mimetypes` module provides an alternative. (Contributed by Victor Stinner in gh-104773.)

  - `msilib`. (Contributed by Zachary Ware in gh-104773.)

  - `nis`. (Contributed by Victor Stinner in gh-104773.)

  - `nntplib`: the nntplib PyPI project can be used instead. (Contributed by Victor Stinner in gh-104773.)

  - `ossaudiodev`: use the pygame project for audio playback. (Contributed by Victor Stinner in gh-104780.)

  - `pipes`: use the `subprocess` module instead. (Contributed by Victor Stinner in gh-104773.)

  - `sndhdr`: use the projects filetype, puremagic, or python-magic instead. (Contributed by Victor Stinner in gh-104773.)

  - `spwd`: the python-pam project can be used instead. (Contributed by Victor Stinner in gh-104773.)

  - `sunau`. (Contributed by Victor Stinner in gh-104773.)

  - `telnetlib`, use the projects telnetlib3 or Exscript instead. (Contributed by Victor Stinner in gh-104773.)

  - `uu`: the `base64` module is a modern alternative. (Contributed by Victor Stinner in gh-104773.)

  - `xdrlib`. (Contributed by Victor Stinner in gh-104773.)

- Remove the `2to3` program and the `lib2to3` module, deprecated in Python 3.11. (Contributed by Victor Stinner in gh-104780.)

- Remove the `tkinter.tix` module, deprecated in Python 3.6. The third-party Tix library which the module wrapped is unmaintained. (Contributed by Zachary Ware in gh-75552.)

### configparser

- Remove the undocumented `configparser.LegacyInterpolation` class, deprecated in the docstring since Python 3.2, and with a deprecation warning since Python 3.11. (Contributed by Hugo van Kemenade in gh-104886.)

### importlib

- Remove deprecated `__getitem__()` access for `importlib.metadata.EntryPoint` objects. (Contributed by Jason R. Coombs in gh-113175.)

### locale

- Remove `locale.resetlocale()` function deprecated in Python 3.11: use `locale.setlocale(locale.LC_ALL, "")` instead. (Contributed by Victor Stinner in gh-104783.)

### logging

- `logging`: Remove undocumented and untested `Logger.warn()` and `LoggerAdapter.warn()` methods and `logging.warn()` function. Deprecated since Python 3.3, they were aliases to the `logging.Logger.warning()` method, `logging.LoggerAdapter.warning()` method and `logging.warning()` function. (Contributed by Victor Stinner in gh-105376.)

### pathlib

- Remove support for using `pathlib.Path` objects as context managers. This functionality was deprecated and made a no-op in Python 3.9.

### re

- Remove undocumented, never working, and deprecated `re.template` function and `re.TEMPLATE` flag (and `re.T` alias). (Contributed by Serhiy Storchaka and Nikita Sobolev in gh-105687.)

### turtle

- Remove the `turtle.RawTurtle.settiltangle()` method, deprecated in docs since Python 3.1 and with a deprecation warning since Python 3.11. (Contributed by Hugo van Kemenade in gh-104876.)

### typing

- Namespaces `typing.io` and `typing.re`, deprecated in Python 3.8, are now removed. The items in those namespaces can be imported directly from `typing`. (Contributed by Sebastian Rittau in gh-92871.)

- Remove support for the keyword-argument method of creating `typing.TypedDict` types, deprecated in Python 3.11. (Contributed by Tomas Roun in gh-104786.)

### unittest

- Remove the following `unittest` functions, deprecated in Python 3.11:

  - `unittest.findTestCases()`

  - `unittest.makeSuite()`

  - `unittest.getTestCaseNames()`

  请改用 `TestLoader` 方法:

  - `unittest.TestLoader.loadTestsFromModule()`

  - `unittest.TestLoader.loadTestsFromTestCase()`

  - `unittest.TestLoader.getTestCaseNames()`

  (Contributed by Hugo van Kemenade in gh-104835.)

- Remove the untested and undocumented `unittest.TestProgram.usageExit()` method, deprecated in Python 3.11. (Contributed by Hugo van Kemenade in gh-104992.)

### urllib

- Remove cafile, capath and cadefault parameters of the `urllib.request.urlopen()` function, deprecated in Python 3.6: pass the context parameter instead. Use `ssl.SSLContext.load_cert_chain()` to load specific certificates, or let `ssl.create_default_context()` select the system's trusted CA certificates for you. (Contributed by Victor Stinner in gh-105382.)

### webbrowser

- Remove the untested and undocumented `webbrowser` `MacOSX` class, deprecated in Python 3.11. Use the `MacOSXOSAScript` class (introduced in Python 3.2) instead. (Contributed by Hugo van Kemenade in gh-104804.)

- Remove deprecated `webbrowser.MacOSXOSAScript._name` attribute. Use `webbrowser.MacOSXOSAScript.name` attribute instead. (Contributed by Nikita Sobolev in gh-105546.)

## New Deprecations

- Removed chained `classmethod` descriptors (introduced in gh-63272). This can no longer be used to wrap other descriptors such as `property`. The core design of this feature was flawed and caused a number of downstream problems. To "pass-through" a `classmethod`, consider using the `__wrapped__` attribute that was added in Python 3.10. (Contributed by Raymond Hettinger in gh-89519.)

- `array`: `array`'s `'u'` format code, deprecated in docs since Python 3.3, emits `DeprecationWarning` since 3.13 and will be removed in Python 3.16. Use the `'w'` format code instead. (Contributed by Hugo van Kemenade in gh-80480.)

- `ctypes`: Deprecate undocumented `ctypes.SetPointerType()` and `ctypes.ARRAY()` functions. Replace `ctypes.ARRAY(item_type, size)` with `item_type * size`. (Contributed by Victor Stinner in gh-105733.)

- `decimal`: 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.)

- `dis`: The `dis.HAVE_ARGUMENT` separator is deprecated. Check membership in `hasarg` instead. (Contributed by Irit Katriel in gh-109319.)

- 帧对象: Calling `frame.clear()` on a suspended frame raises `RuntimeError` (as has always been the case for an executing frame). (Contributed by Irit Katriel in gh-79932.)

- `getopt` and `optparse` modules: They are now soft deprecated: the `argparse` module should be used for new projects. Previously, the `optparse` module was already deprecated, its removal was not scheduled, and no warnings was emitted: so there is no change in practice. (Contributed by Victor Stinner in gh-106535.)

- `gettext`: Emit deprecation warning for non-integer numbers in `gettext` functions and methods that consider plural forms even if the translation was not found. (Contributed by Serhiy Storchaka in gh-88434.)

- `glob`: The undocumented `glob.glob0()` and `glob.glob1()` functions are deprecated. Use `glob.glob()` and pass a directory to its root_dir argument instead. (Contributed by Barney Gale in gh-117337.)

- `http.server`: `http.server.CGIHTTPRequestHandler` now emits a `DeprecationWarning` as it will be removed in 3.15. Process-based CGI HTTP servers have been out of favor for a very long time. This code was outdated, unmaintained, and rarely used. It has a high potential for both security and functionality bugs. This includes removal of the `--cgi` flag to the `python -m http.server` command line in 3.15.

- `mimetypes`: Passing file path instead of URL in `guess_type()` is soft deprecated. Use `guess_file_type()` instead. (Contributed by Serhiy Storchaka in gh-66543.)

- `re`: Passing optional arguments maxsplit, count and flags in module-level functions `re.split()`, `re.sub()` and `re.subn()` as positional arguments is now deprecated. In future Python versions these parameters will be keyword-only. (Contributed by Serhiy Storchaka in gh-56166.)

- `pathlib`: `pathlib.PurePath.is_reserved()` is deprecated and scheduled for removal in Python 3.15. Use `os.path.isreserved()` to detect reserved paths on Windows.

- `platform`: `java_ver()` is deprecated and will be removed in 3.15. It was largely untested, had a confusing API, and was only useful for Jython support. (Contributed by Nikita Sobolev in gh-116349.)

- `pydoc`: Deprecate undocumented `pydoc.ispackage()` function. (Contributed by Zackery Spytz in gh-64020.)

- `sqlite3`: Passing more than one positional argument to `sqlite3.connect()` and the `sqlite3.Connection` constructor is deprecated. The remaining parameters will become keyword-only in Python 3.15.

  Deprecate passing name, number of arguments, and the callable as keyword arguments for the following `sqlite3.Connection` APIs:

  - `create_function()`

  - `create_aggregate()`

  已弃用通过关键字参数形式为下列 `sqlite3.Connection` API 传入可调用对象：

  - `set_authorizer()`

  - `set_progress_handler()`

  - `set_trace_callback()`

  受影响的形参将在 Python 3.15 中成为仅限位置形参。

  （由 Erlend E. Aasland 在 gh-107948 和 gh-108278 中贡献。）

- `sys`: `sys._enablelegacywindowsfsencoding()` function. Replace it with the `PYTHONLEGACYWINDOWSFSENCODING` environment variable. (Contributed by Inada Naoki in gh-73427.)

- `tarfile`: The undocumented and unused `tarfile` attribute of `tarfile.TarFile` is deprecated and scheduled for removal in Python 3.16.

- `traceback`: The field exc_type of `traceback.TracebackException` is deprecated. Use exc_type_str instead.

- `typing`:

  - Creating a `typing.NamedTuple` class using keyword arguments to denote the fields (`NT = NamedTuple("NT", x=int, y=int)`) is deprecated, and will be disallowed in Python 3.15. Use the class-based syntax or the functional syntax instead. (Contributed by Alex Waygood in gh-105566.)

  - When using the functional syntax to create a `typing.NamedTuple` class or a `typing.TypedDict` class, failing to pass a value to the 'fields' parameter (`NT = NamedTuple("NT")` or `TD = TypedDict("TD")`) is deprecated. Passing `None` to the 'fields' parameter (`NT = NamedTuple("NT", None)` or `TD = TypedDict("TD", None)`) is also deprecated. Both will be disallowed in Python 3.15. To create a NamedTuple class with 0 fields, use `class NT(NamedTuple): pass` or `NT = NamedTuple("NT", [])`. To create a TypedDict class with 0 fields, use `class TD(TypedDict): pass` or `TD = 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 the `typing` module, it has yet to be supported by any major type checkers. (Contributed by Alex Waygood in gh-106309.)

  - `typing.AnyStr` is deprecated. In Python 3.16, it will be removed from `typing.__all__`, and a `DeprecationWarning` will be emitted when it is imported or accessed. It will be removed entirely in Python 3.18. Use the new type parameter syntax instead. (Contributed by Michael The in gh-107116.)

- 用户定义函数: Assignment to a function's `__code__` attribute where the new code object's type does not match the function's type, is deprecated. The different types are: plain function, generator, async generator and coroutine. (Contributed by Irit Katriel in gh-81137.)

- `wave`: Deprecate the `getmark()`, `setmark()` and `getmarkers()` methods of the `wave.Wave_read` and `wave.Wave_write` classes. They will be removed in Python 3.15. (Contributed by Victor Stinner in gh-105096.)

### 计划在 Python 3.14 中移除

- `argparse`: `argparse.BooleanOptionalAction` 的 type, choices 和 metavar 形参已被弃用并将在 3.14 中移除。 （由 Nikita Sobolev 在 gh-92248 中贡献。）

- `ast`: The following features have been deprecated in documentation since Python 3.8, now cause a `DeprecationWarning` to be emitted at runtime when they are accessed or used, and will be removed in Python 3.14:

  - `ast.Num`

  - `ast.Str`

  - `ast.Bytes`

  - `ast.NameConstant`

  - `ast.Ellipsis`

  请改用 `ast.Constant`。 （由 Serhiy Storchaka 在 gh-90953 中贡献。）

- `collections.abc`: Deprecated `collections.abc.ByteString`. Prefer `Sequence` or `Buffer`. For use in typing, prefer a union, like `bytes | bytearray`, or `collections.abc.Buffer`. (Contributed by Shantanu Jain in gh-91896.)

- `email`: 已弃用 `email.utils.localtime()` 中的 isdst 形参。 （由 Alan Williams 在 gh-72346 中贡献。）

- `importlib`: `__package__` and `__cached__` will cease to be set or taken into consideration by the import system (gh-97879).

- `importlib.abc` deprecated classes:

  - `importlib.abc.ResourceReader`

  - `importlib.abc.Traversable`

  - `importlib.abc.TraversableResources`

  使用 `importlib.resources.abc` 类代替:

  - `importlib.resources.abc.Traversable`

  - `importlib.resources.abc.TraversableResources`

  （由 Jason R. Coombs 和 Hugo van Kemenade 在 gh-93963 中贡献。）

- `itertools` 具有对 copy, deepcopy 和 pickle 等操作的未写入文档的、低效的、历史上充满问题的且不稳定的支持。 这将在 3.14 中移除以显著减少代码量和维护负担。 （由 Raymond Hettinger 在 gh-101588 中贡献。）

- `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 the `get_context()` or `set_start_method()` APIs to explicitly specify when your code requires `'fork'`. See 上下文和启动方法.

- `pathlib`: `is_relative_to()` and `relative_to()`: passing additional arguments is deprecated.

- `pkgutil`: `find_loader()` and `get_loader()` now raise `DeprecationWarning`; use `importlib.util.find_spec()` instead. (Contributed by Nikita Sobolev in gh-97850.)

- `pty`:

  - `master_open()`: use `pty.openpty()`.

  - `slave_open()`: use `pty.openpty()`.

- `sqlite3`:

  - `version` and `version_info`.

  - `execute()` and `executemany()` if named placeholders are used and parameters is a sequence instead of a `dict`.

  - date and datetime adapter, date and timestamp converter: see the `sqlite3` documentation for suggested replacement recipes.

- `types.CodeType`: Accessing `co_lnotab` was deprecated in PEP 626 since 3.10 and was planned to be removed in 3.12, but it only got a proper `DeprecationWarning` in 3.12. May be removed in 3.14. (Contributed by Nikita Sobolev in gh-101866.)

- `typing`: `typing.ByteString`, deprecated since Python 3.9, now causes a `DeprecationWarning` to be emitted when it is used.

- `urllib`: `urllib.parse.Quoter` is deprecated: it was not intended to be a public API. (Contributed by Gregory P. Smith in gh-88168.)

### Python 3.15 中的待移除功能

- `http.server.CGIHTTPRequestHandler` will be removed along with its related `--cgi` flag to `python -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. Use `locale.setlocale()`, `locale.getencoding()` and `locale.getlocale()` instead. (Contributed by Hugo van Kemenade in gh-111187.)

- `pathlib`: `pathlib.PurePath.is_reserved()` is deprecated and scheduled for removal in Python 3.15. Use `os.path.isreserved()` to detect reserved paths on Windows.

- `platform`: `java_ver()` is deprecated and will be removed in 3.15. It was largely untested, had a confusing API, and was only useful for Jython support. (Contributed by Nikita Sobolev in gh-116349.)

- `threading`: Passing any arguments 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 from `threading.RLock()` in Python 3.15. (Contributed by Nikita Sobolev in gh-102029.)

- `typing.NamedTuple`:

  - 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. Passing `None` to 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, use `class NT(NamedTuple): pass` or `NT = 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. Passing `None` to 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, use `class TD(TypedDict): pass` or `TD = TypedDict("TD", {})`.

- `wave`: Deprecate the `getmark()`, `setmark()` and `getmarkers()` methods of the `wave.Wave_read` and `wave.Wave_write` classes. They will be removed in Python 3.15. (Contributed by Victor Stinner in gh-105096.)

### Pending Removal in Python 3.16

- `array.array` `'u'` type (`wchar_t`): use the `'w'` type instead (`Py_UCS4`).

### 计划在未来版本中移除

下列 API 在更早的 Python 版本中已被弃用并将被移除，但目前还没有确定它们的移除日期。

- `argparse`: Nesting argument groups and nesting mutually exclusive groups are deprecated.

- `builtins`:

  - `~bool`, bitwise inversion on bool.

  - `bool(NotImplemented)`.

  - Generators: `throw(type, exc, tb)` and `athrow(type, exc, tb)` signature is deprecated: use `throw(exc)` and `athrow(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 keywords `and`, `else`, `for`, `if`, `in`, `is` and `or`. 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 of `int`.

  - Support for `__float__()` method returning a strict subclass of `float`: these methods will be required to return an instance of `float`.

  - Support for `__complex__()` method returning a strict subclass of `complex`: these methods will be required to return an instance of `complex`.

  - Delegation of `int()` to `__trunc__()` method.

- `calendar`: `calendar.January` 和 `calendar.February` 常量已被弃用并由 `calendar.JANUARY` 和 `calendar.FEBRUARY` 替代。 （由 Prince Roshan 在 gh-103636 中贡献。）

- `codeobject.co_lnotab`: use the `codeobject.co_lines()` method instead.

- `datetime`:

  - `utcnow()`: use `datetime.datetime.now(tz=datetime.UTC)`.

  - `utcfromtimestamp()`: use `datetime.datetime.fromtimestamp(timestamp, tz=datetime.UTC)`.

- `gettext`: Plural value must be an integer.

- `importlib`:

  - `load_module()` method: use `exec_module()` instead.

  - `cache_from_source()` debug_override parameter is deprecated: use the optimization parameter instead.

- `importlib.metadata`:

  - `EntryPoints` tuple interface.

  - Implicit `None` on return values.

- `mailbox`: Use of StringIO input and text mode is deprecated, use BytesIO and binary mode instead.

- `os`: Calling `os.register_at_fork()` in multi-threaded process.

- `pydoc.ErrorDuringImport`: A tuple value for exc_info parameter is deprecated, use an exception instance.

- `re`: More strict rules are now applied for numerical group references and group names in regular expressions. Only sequence of ASCII digits is now accepted as a numerical reference. The group name in bytes patterns and replacement strings can now only contain ASCII letters and digits and underscore. (Contributed by Serhiy Storchaka in gh-91760.)

- `sre_compile`, `sre_constants` and `sre_parse` modules.

- `shutil`: `rmtree()`'s onerror parameter is deprecated in Python 3.12; use the onexc parameter instead.

- `ssl` options and protocols:

  - `ssl.SSLContext` without protocol argument is deprecated.

  - `ssl.SSLContext`: `set_npn_protocols()` and `selected_npn_protocol()` are deprecated: use ALPN instead.

  - `ssl.OP_NO_SSL*` 选项

  - `ssl.OP_NO_TLS*` 选项

  - `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`

- `sysconfig.is_python_build()` check_home parameter is deprecated and ignored.

- `threading` methods:

  - `threading.Condition.notifyAll()`: use `notify_all()`.

  - `threading.Event.isSet()`: use `is_set()`.

  - `threading.Thread.isDaemon()`, `threading.Thread.setDaemon()`: use `threading.Thread.daemon` attribute.

  - `threading.Thread.getName()`, `threading.Thread.setName()`: use `threading.Thread.name` attribute.

  - `threading.currentThread()`: use `threading.current_thread()`.

  - `threading.activeCount()`: use `threading.active_count()`.

- `typing.Text` (gh-92332).

- `unittest.IsolatedAsyncioTestCase`: it is deprecated to return a value that is not `None` from a test case.

- `urllib.parse` deprecated functions: `urlparse()` instead

  - `splitattr()`

  - `splithost()`

  - `splitnport()`

  - `splitpasswd()`

  - `splitport()`

  - `splitquery()`

  - `splittag()`

  - `splittype()`

  - `splituser()`

  - `splitvalue()`

  - `to_bytes()`

- `urllib.request`: `URLopener` and `FancyURLopener` style of invoking requests is deprecated. Use newer `urlopen()` functions and methods.

- `wsgiref`: `SimpleHandler.stdout.write()` should not do partial writes.

- `xml.etree.ElementTree`: Testing the truth value of an `Element` is deprecated. In a future release it it will always return `True`. Prefer explicit `len(elem)` or `elem is not None` tests instead.

- `zipimport.zipimporter.load_module()` is deprecated: use `exec_module()` instead.

## CPython Bytecode Changes

- The oparg of `YIELD_VALUE` is now `1` if the yield is part of a yield-from or await, and `0` otherwise. The oparg of `RESUME` was changed to add a bit indicating whether the except-depth is 1, which is needed to optimize closing of generators. (Contributed by Irit Katriel in gh-111354.)

## C API 的变化

### 新的特性

- You no longer have to define the `PY_SSIZE_T_CLEAN` macro before including `Python.h` when using `#` formats in format codes. APIs accepting the format codes always use `Py_ssize_t` for `#` formats. (Contributed by Inada Naoki in gh-104922.)

- The keywords parameter of `PyArg_ParseTupleAndKeywords()` and `PyArg_VaParseTupleAndKeywords()` now has type char *const* in C and const char *const* in C++, instead of char**. It makes these functions compatible with arguments of type const char *const*, const char** or char *const* in C++ and char *const* in C without an explicit type cast. This can be overridden with the `PY_CXX_CONST` macro. (Contributed by Serhiy Storchaka in gh-65210.)

- Add `PyImport_AddModuleRef()`: similar to `PyImport_AddModule()`, but return a strong reference instead of a borrowed reference. (Contributed by Victor Stinner in gh-105922.)

- Add `PyWeakref_GetRef()` function: similar to `PyWeakref_GetObject()` but returns a strong reference, or `NULL` if the referent is no longer live. (Contributed by Victor Stinner in gh-105927.)

- Add `PyObject_GetOptionalAttr()` and `PyObject_GetOptionalAttrString()`, variants of `PyObject_GetAttr()` and `PyObject_GetAttrString()` which don't raise `AttributeError` if the attribute is not found. These variants are more convenient and faster if the missing attribute should not be treated as a failure. (Contributed by Serhiy Storchaka in gh-106521.)

- Add `PyMapping_GetOptionalItem()` and `PyMapping_GetOptionalItemString()`: variants of `PyObject_GetItem()` and `PyMapping_GetItemString()` which don't raise `KeyError` if the key is not found. These variants are more convenient and faster if the missing key should not be treated as a failure. (Contributed by Serhiy Storchaka in gh-106307.)

- Add fixed variants of functions which silently ignore errors:

  - `PyObject_HasAttrWithError()` 替代 `PyObject_HasAttr()`。

  - `PyObject_HasAttrStringWithError()` 替代 `PyObject_HasAttrString()`。

  - `PyMapping_HasKeyWithError()` 替代 `PyMapping_HasKey()`。

  - `PyMapping_HasKeyStringWithError()` replaces `PyMapping_HasKeyString()`.

  New functions return not only `1` for true and `0` for false, but also `-1` for error.

  (Contributed by Serhiy Storchaka in gh-108511.)

- If Python is built in debug mode or `with assertions`, `PyTuple_SET_ITEM()` and `PyList_SET_ITEM()` now check the index argument with an assertion. (Contributed by Victor Stinner in gh-106168.)

- Add `PyModule_Add()` function: similar to `PyModule_AddObjectRef()` and `PyModule_AddObject()` but always steals a reference to the value. (Contributed by Serhiy Storchaka in gh-86493.)

- Add `PyDict_GetItemRef()` and `PyDict_GetItemStringRef()` functions: similar to `PyDict_GetItemWithError()` but returning a strong reference instead of a borrowed reference. Moreover, these functions return -1 on error and so checking `PyErr_Occurred()` is not needed. (Contributed by Victor Stinner in gh-106004.)

- Added `PyDict_SetDefaultRef()`, which is similar to `PyDict_SetDefault()` but returns a strong reference instead of a borrowed reference. This function returns `-1` on error, `0` on insertion, and `1` if the key was already present in the dictionary. (Contributed by Sam Gross in gh-112066.)

- Add `PyDict_ContainsString()` function: same as `PyDict_Contains()`, but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject *. (Contributed by Victor Stinner in gh-108314.)

- Added `PyList_GetItemRef()` function: similar to `PyList_GetItem()` but returns a strong reference instead of a borrowed reference.

- Add `Py_IsFinalizing()` function: check if the main Python interpreter is shutting down. (Contributed by Victor Stinner in gh-108014.)

- Add `PyLong_AsInt()` function: similar to `PyLong_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()` and `PyObject_ClearManagedDict()` functions which must be called by the traverse and clear functions of a type using `Py_TPFLAGS_MANAGED_DICT` flag. The pythoncapi-compat project can be used to get these functions on Python 3.11 and 3.12. (Contributed by Victor Stinner in gh-107073.)

- Add `PyUnicode_EqualToUTF8AndSize()` and `PyUnicode_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 to `PyThreadState_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 to `PySys_Audit()`, but pass event arguments as a Python `tuple` object. (Contributed by Victor Stinner in gh-85283.)

- `PyArg_ParseTupleAndKeywords()` now supports non-ASCII keyword parameter names. (Contributed by Serhiy Storchaka in gh-110815.)

- Add `PyMem_RawMalloc()`, `PyMem_RawCalloc()`, `PyMem_RawRealloc()` and `PyMem_RawFree()` to the limited C API (version 3.13). (Contributed by Victor Stinner in gh-85283.)

- Add `PySys_Audit()` and `PySys_AuditTuple()` functions to the limited C API. (Contributed by Victor Stinner in gh-85283.)

- Add `PyErr_FormatUnraisable()` function: similar to `PyErr_WriteUnraisable()`, but allow customizing the warning message. (Contributed by Serhiy Storchaka in gh-108082.)

- Add `PyList_Extend()` and `PyList_Clear()` functions: similar to Python `list.extend()` and `list.clear()` methods. (Contributed by Victor Stinner in gh-111138.)

- Add `PyDict_Pop()` and `PyDict_PopString()` functions: remove a key from a dictionary and optionally return the removed value. This is similar to `dict.pop()`, but without the default value and not raising `KeyError` if the key is missing. (Contributed by Stefan Behnel and Victor Stinner in gh-111262.)

- Add `Py_HashPointer()` function to hash a pointer. (Contributed by Victor Stinner in gh-111545.)

- Add `PyObject_GenericHash()` function that implements the default hashing function of a Python object. (Contributed by Serhiy Storchaka in gh-113024.)

- 新增 PyTime C API：

  - `PyTime_t` 类型。

  - `PyTime_MIN` 和 `PyTime_MAX` 常量。

  - 新增函数：

    - `PyTime_AsSecondsDouble()`。

    - `PyTime_Monotonic()`。

    - `PyTime_MonotonicRaw()`。

    - `PyTime_PerfCounter()`。

    - `PyTime_PerfCounterRaw()`。

    - `PyTime_Time()`。

    - `PyTime_TimeRaw()`。

  （由 Victor Stinner 和 Petr Viktorin 在 gh-110850 中贡献。）

- Add `PyLong_AsNativeBytes()`, `PyLong_FromNativeBytes()` and `PyLong_FromUnsignedNativeBytes()` functions to simplify converting between native integer types and Python `int` objects. (Contributed by Steve Dower in gh-111140.)

- Add `PyType_GetFullyQualifiedName()` function to get the type's fully qualified name. Equivalent to `f"{type.__module__}.{type.__qualname__}"`, or `type.__qualname__` if `type.__module__` is not a string or is equal to `"builtins"`. (Contributed by Victor Stinner in gh-111696.)

- Add `PyType_GetModuleName()` function to get the type's module name. Equivalent to getting the `type.__module__` attribute. (Contributed by Eric Snow and Victor Stinner in gh-111696.)

- Add support for `%T`, `%#T`, `%N` and `%#N` formats to `PyUnicode_FromFormat()`: format the fully qualified name of an object type and of a type: call `PyType_GetModuleName()`. See PEP 737 for more information. (Contributed by Victor Stinner in gh-111696.)

- Add `Py_GetConstant()` and `Py_GetConstantBorrowed()` functions to get constants. For example, `Py_GetConstant(Py_CONSTANT_ZERO)` returns a strong reference to the constant zero. (Contributed by Victor Stinner in gh-115754.)

- Add `PyType_GetModuleByDef()` to the limited C API (Contributed by Victor Stinner in gh-116936.)

- Add two new functions to the C-API, `PyRefTracer_SetTracer()` and `PyRefTracer_GetTracer()`, that allows to track object creation and destruction the same way the `tracemalloc` module does. (Contributed by Pablo Galindo in gh-93502.)

- Add `PyEval_GetFrameBuiltins()`, `PyEval_GetFrameGlobals()`, and `PyEval_GetFrameLocals()` to the C API. These replacements for `PyEval_GetBuiltins()`, `PyEval_GetGlobals()`, and `PyEval_GetLocals()` return strong references rather than borrowed references. (Added as part of PEP 667.)

- Add `PyMutex` API, a lightweight mutex that occupies a single byte. The `PyMutex_Lock()` function will release the GIL (if currently held) if the operation needs to block. (Contributed by Sam Gross in gh-108724.)

## 构建变化

- The `configure` option `--with-system-libmpdec` now defaults to `yes`. The bundled copy of `libmpdecimal` will be removed in Python 3.15.

- Autoconf 2.71 and aclocal 1.16.4 are now required to regenerate the `configure` script. (Contributed by Christian Heimes in gh-89886.)

- SQLite 3.15.2 or newer is required to build the `sqlite3` extension module. (Contributed by Erlend Aasland in gh-105875.)

- Python built with `configure` `--with-trace-refs` (tracing references) is now ABI compatible with the Python release build and debug build. (Contributed by Victor Stinner in gh-108634.)

- Building CPython now requires a compiler with support for the C11 atomic library, GCC built-in atomic functions, or MSVC interlocked intrinsics.

- The `errno`, `fcntl`, `grp`, `md5`, `pwd`, `resource`, `termios`, `winsound`, `_ctypes_test`, `_multiprocessing.posixshmem`, `_scproxy`, `_stat`, `_statistics`, `_testconsole`, `_testimportmultiple` and `_uuid` C extensions are now built with the limited C API. (Contributed by Victor Stinner in gh-85283.)

- `wasm32-wasi` is now a PEP 11 tier 2 platform. (Contributed by Brett Cannon in gh-115192.)

- `wasm32-emscripten` is no longer a PEP 11 supported platform. (Contributed by Brett Cannon in gh-115192.)

- Python now bundles the mimalloc library. It is licensed under the MIT license; see mimalloc license. The bundled mimalloc has custom changes, see gh-113141 for details. (Contributed by Dino Viehland in gh-109914.)

- On POSIX systems, the pkg-config (`.pc`) filenames now include the ABI flags. For example, the free-threaded build generates `python-3.13t.pc` and the debug build generates `python-3.13d.pc`.

## Porting to Python 3.13

本节列出了先前描述的更改以及可能需要更改代码的其他错误修正.

### Python API 的变化

- An `OSError` is now raised by `getpass.getuser()` for any failure to retrieve a username, instead of `ImportError` on non-Unix platforms or `KeyError` on Unix platforms where the password database is empty.

- 现在 `threading` 模块会预期 `_thread` 模块具有 `_is_main_interpreter` 属性。 它是一个不带参数的函数并会在当前解释器为主解释器时返回 `True`。

  Any library or application that provides a custom `_thread` module must provide `_is_main_interpreter()`, just like the module's other "private" attributes. (See gh-112826.)

- `mailbox.Maildir` now ignores files with a leading dot. (Contributed by Zackery Spytz in gh-65559.)

- `pathlib.Path.glob()` and `rglob()` now return both files and directories if a pattern that ends with "`**`" is given, rather than directories only. Users may add a trailing slash to match only directories.

- The value of the `mode` attribute of `gzip.GzipFile` was changed from integer (`1` or `2`) to string (`'rb'` or `'wb'`). The value of the `mode` attribute of the readable file-like object returned by `zipfile.ZipFile.open()` was changed from `'r'` to `'rb'`. (Contributed by Serhiy Storchaka in gh-115961.)

- `functools.partial` now emits a `FutureWarning` when it is used as a method. Its behavior will be changed in future Python versions. Wrap it in `staticmethod()` if you want to preserve the old behavior. (Contributed by Serhiy Storchaka in gh-121027.)

- Calling `locals()` in an optimized scope now produces an independent snapshot on each call, and hence no longer implicitly updates previously returned references. Obtaining the legacy CPython behaviour now requires explicit calls to update the initially returned dictionary with the results of subsequent calls to `locals()`. Code execution functions that implicitly target `locals()` (such as `exec` and `eval`) must be passed an explicit namespace to access their results in an optimized scope. (Changed as part of PEP 667.)

- Calling `locals()` from a comprehension at module or class scope (including via `exec` or `eval`) once more behaves as if the comprehension were running as an independent nested function (i.e. the local variables from the containing scope are not included). In Python 3.12, this had changed to include the local variables from the containing scope when implementing PEP 709. (Changed as part of PEP 667.)

- Accessing `FrameType.f_locals` in an optimized scope now returns a write-through proxy rather than a snapshot that gets updated at ill-specified times. If a snapshot is desired, it must be created explicitly with `dict` or the proxy's `.copy()` method. (Changed as part of PEP 667.)

### C API 的变化

- `Python.h` no longer includes the `<ieeefp.h>` standard header. It was included for the `finite()` function which is now provided by the `<math.h>` header. It should now be included explicitly if needed. Remove also the `HAVE_IEEEFP_H` macro. (Contributed by Victor Stinner in gh-108765.)

- `Python.h` no longer includes these standard header files: `<time.h>`, `<sys/select.h>` and `<sys/time.h>`. If needed, they should now be included explicitly. For example, `<time.h>` provides the `clock()` and `gmtime()` functions, `<sys/select.h>` provides the `select()` function, and `<sys/time.h>` provides the `futimes()`, `gettimeofday()` and `setitimer()` functions. (Contributed by Victor Stinner in gh-108765.)

- On Windows, `Python.h` no longer includes the `<stddef.h>` standard header file. If needed, it should now be included explicitly. For example, it provides `offsetof()` function, and `size_t` and `ptrdiff_t` types. Including `<stddef.h>` explicitly was already needed by all other platforms, the `HAVE_STDDEF_H` macro is only defined on Windows. (Contributed by Victor Stinner in gh-108765.)

- If the `Py_LIMITED_API` macro is defined, `Py_BUILD_CORE`, `Py_BUILD_CORE_BUILTIN` and `Py_BUILD_CORE_MODULE` macros are now undefined by `<Python.h>`. (Contributed by Victor Stinner in gh-85283.)

- The old trashcan macros `Py_TRASHCAN_SAFE_BEGIN` and `Py_TRASHCAN_SAFE_END` were removed. They should be replaced by the new macros `Py_TRASHCAN_BEGIN` and `Py_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
      }

  应当按照以下方式迁移到新版宏:

      static void
      mytype_dealloc(mytype *p)
      {
          PyObject_GC_UnTrack(p);
          Py_TRASHCAN_BEGIN(p, mytype_dealloc)
          ...
          Py_TRASHCAN_END
      }

  Note that `Py_TRASHCAN_BEGIN` has a second argument which should be the deallocation function it is in. The new macros were added in Python 3.8 and the old macros were deprecated in Python 3.11. (Contributed by Irit Katriel in gh-105111.)

- Functions `PyDict_GetItem()`, `PyDict_GetItemString()`, `PyMapping_HasKey()`, `PyMapping_HasKeyString()`, `PyObject_HasAttr()`, `PyObject_HasAttrString()`, and `PySys_GetObject()`, which clear all errors which occurred when calling them, now report them using `sys.unraisablehook()`. You may replace them with other functions as recommended in the documentation. (Contributed by Serhiy Storchaka in gh-106672.)

- `PyCode_GetFirstFree()` is an unstable API now and has been renamed to `PyUnstable_Code_GetFirstFree()`. (Contributed by Bogdan Romanyuk in gh-115781.)

- The effects of mutating the dictionary returned from `PyEval_GetLocals()` in an optimized scope have changed. New dict entries added this way will now only be visible to subsequent `PyEval_GetLocals()` calls in that frame, as `PyFrame_GetLocals()`, `locals()`, and `FrameType.f_locals` no longer access the same underlying cached dictionary. Changes made to entries for actual variable names and names added via the write-through proxy interfaces will be overwritten on subsequent calls to `PyEval_GetLocals()` in that frame. The recommended code update depends on how the function was being used, so refer to the deprecation notice on the function for details. (Changed as part of PEP 667.)

- Calling `PyFrame_GetLocals()` in an optimized scope now returns a write-through proxy rather than a snapshot that gets updated at ill-specified times. If a snapshot is desired, it must be created explicitly (e.g. with `PyDict_Copy()`) or by calling the new `PyEval_GetFrameLocals()` API. (Changed as part of PEP 667.)

- `PyFrame_FastToLocals()` and `PyFrame_FastToLocalsWithError()` no longer have any effect. Calling these functions has been redundant since Python 3.11, when `PyFrame_GetLocals()` was first introduced. (Changed as part of PEP 667.)

- `PyFrame_LocalsToFast()` no longer has any effect. Calling this function is redundant now that `PyFrame_GetLocals()` returns a write-through proxy for optimized scopes. (Changed as part of PEP 667.)

### Removed C APIs

- Remove many APIs (functions, macros, variables) with names prefixed by `_Py` or `_PY` (considered as private API). If your project is affected by one of these removals and you consider that the removed API should remain available, please open a new issue to request a public C API and add `cc @vstinner` to the issue to notify Victor Stinner. (Contributed by Victor Stinner in gh-106320.)

- Remove functions deprecated in Python 3.9:

  - `PyEval_CallObject()`, `PyEval_CallObjectWithKeywords()`: use `PyObject_CallNoArgs()` or `PyObject_Call()` instead. Warning: `PyObject_Call()` positional arguments must be a `tuple` and must not be `NULL`, keyword arguments must be a `dict` or `NULL`, whereas removed functions checked arguments type and accepted `NULL` positional and keyword arguments. To replace `PyEval_CallObjectWithKeywords(func, NULL, kwargs)` with `PyObject_Call()`, pass an empty tuple as positional arguments using `PyTuple_New(0)`.

  - `PyEval_CallFunction()`: use `PyObject_CallFunction()` instead.

  - `PyEval_CallMethod()`: use `PyObject_CallMethod()` instead.

  - `PyCFunction_Call()`: use `PyObject_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()`: Use `PyObject_CheckBuffer()` to test if the object supports the buffer protocol. Note that `PyObject_CheckBuffer()` doesn't guarantee that `PyObject_GetBuffer()` will succeed. To test if the object is actually readable, see the next example of `PyObject_GetBuffer()`.

  - `PyObject_AsCharBuffer()`, `PyObject_AsReadBuffer()`: `PyObject_GetBuffer()` and `PyBuffer_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()`: Use `PyObject_GetBuffer()` and `PyBuffer_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()`: use `PyConfig.warnoptions` instead.

  - `PySys_AddWarnOption()`: use `PyConfig.warnoptions` instead.

  - `PySys_AddXOption()`: use `PyConfig.xoptions` instead.

  - `PySys_HasWarnOptions()`: use `PyConfig.xoptions` instead.

  - `PySys_SetPath()`: set `PyConfig.module_search_paths` instead.

  - `Py_SetPath()`: set `PyConfig.module_search_paths` instead.

  - `Py_SetStandardStreamEncoding()`: set `PyConfig.stdio_encoding` instead, and set also maybe `PyConfig.legacy_windows_stdio` (on Windows).

  - `_Py_SetProgramFullPath()`: set `PyConfig.executable` instead.

  Use the new `PyConfig` API of the Python Initialization Configuration instead ( PEP 587), added to Python 3.8. (Contributed by Victor Stinner in gh-105145.)

- Remove `PyEval_ThreadsInitialized()` function, deprecated in Python 3.9. Since Python 3.7, `Py_Initialize()` always creates the GIL: calling `PyEval_InitThreads()` does nothing and `PyEval_ThreadsInitialized()` always returned non-zero. (Contributed by Victor Stinner in gh-105182.)

- Remove `PyEval_AcquireLock()` and `PyEval_ReleaseLock()` functions, deprecated in Python 3.2. They didn't update the current thread state. They can be replaced with:

  - `PyEval_SaveThread()` and `PyEval_RestoreThread()`;

  - low-level `PyEval_AcquireThread()` and `PyEval_RestoreThread()`;

  - or `PyGILState_Ensure()` and `PyGILState_Release()`.

  (Contributed by Victor Stinner in gh-105182.)

- Remove private `_PyObject_FastCall()` function: use `PyObject_Vectorcall()` which is available since Python 3.8 ( PEP 590). (Contributed by Victor Stinner in gh-106023.)

- Remove `cpython/pytime.h` header file: it only contained private functions. (Contributed by Victor Stinner in gh-106316.)

- Remove `_PyInterpreterState_Get()` alias to `PyInterpreterState_Get()` which was kept for backward compatibility with Python 3.8. The pythoncapi-compat project can be used to get `PyInterpreterState_Get()` on Python 3.8 and older. (Contributed by Victor Stinner in gh-106320.)

- The `PyModule_AddObject()` function is now soft deprecated: `PyModule_Add()` or `PyModule_AddObjectRef()` functions should be used instead. (Contributed by Serhiy Storchaka in gh-86493.)

### Deprecated C APIs

- Deprecate the old `Py_UNICODE` and `PY_UNICODE_TYPE` types: use directly the `wchar_t` type instead. Since Python 3.3, `Py_UNICODE` and `PY_UNICODE_TYPE` are just aliases to `wchar_t`. (Contributed by Victor Stinner in gh-105156.)

- Deprecate old Python initialization functions:

  - `PySys_ResetWarnOptions()`: clear `sys.warnoptions` and `warnings.filters` instead.

  - `Py_GetExecPrefix()`: get `sys.exec_prefix` instead.

  - `Py_GetPath()`: get `sys.path` instead.

  - `Py_GetPrefix()`: get `sys.prefix` instead.

  - `Py_GetProgramFullPath()`: get `sys.executable` instead.

  - `Py_GetProgramName()`: get `sys.executable` instead.

  - `Py_GetPythonHome()`: get `PyConfig.home` or `PYTHONHOME` environment variable instead.

  Functions scheduled for removal in Python 3.15. (Contributed by Victor Stinner in gh-105145.)

- Deprecate the `PyImport_ImportModuleNoBlock()` function which is just an alias to `PyImport_ImportModule()` since Python 3.3. Scheduled for removal in Python 3.15. (Contributed by Victor Stinner in gh-105396.)

- Deprecate the `PyWeakref_GetObject()` and `PyWeakref_GET_OBJECT()` functions, which return a borrowed reference: use the new `PyWeakref_GetRef()` function instead, it returns a strong reference. The pythoncapi-compat project can be used to get `PyWeakref_GetRef()` on Python 3.12 and older. (Contributed by Victor Stinner in gh-105927.)

- Deprecate the `PyEval_GetBuiltins()`, `PyEval_GetGlobals()`, and `PyEval_GetLocals()` functions, which return a borrowed reference. Refer to the deprecation notices on each function for their recommended replacements. (Soft deprecated as part of PEP 667.)

### 计划在 Python 3.14 中移除

- 使用 C API 创建基于可变基类创建不可变类型 (`Py_TPFLAGS_IMMUTABLETYPE`)。

- 用于配置 Python 初始化的函数，在 Python 3.11 中已弃用：

  - `PySys_SetArgvEx()`: 改为设置 `PyConfig.argv`。

  - `PySys_SetArgv()`: 改为设置 `PyConfig.argv`。

  - `Py_SetProgramName()`: 改为设置 `PyConfig.program_name`。

  - `Py_SetPythonHome()`: 改为设置 `PyConfig.home`。

  `Py_InitializeFromConfig()` API 应与 `PyConfig` 一起使用。

- 全局配置变量：

  - `Py_DebugFlag`: 使用 `PyConfig.parser_debug`

  - `Py_VerboseFlag`: 使用 `PyConfig.verbose`

  - `Py_QuietFlag`: 使用 `PyConfig.quiet`

  - `Py_InteractiveFlag`: 使用 `PyConfig.interactive`

  - `Py_InspectFlag`: 使用 `PyConfig.inspect`

  - `Py_OptimizeFlag`: 使用 `PyConfig.optimization_level`

  - `Py_NoSiteFlag`: 使用 `PyConfig.site_import`

  - `Py_BytesWarningFlag`: 使用 `PyConfig.bytes_warning`

  - `Py_FrozenFlag`: 使用 `PyConfig.pathconfig_warnings`

  - `Py_IgnoreEnvironmentFlag`: 使用 `PyConfig.use_environment`

  - `Py_DontWriteBytecodeFlag`: 使用 `PyConfig.write_bytecode`

  - `Py_NoUserSiteDirectory`: 使用 `PyConfig.user_site_directory`

  - `Py_UnbufferedStdioFlag`: 使用 `PyConfig.buffered_stdio`

  - `Py_HashRandomizationFlag`: 使用 `PyConfig.use_hash_seed` 和 `PyConfig.hash_seed`

  - `Py_IsolatedFlag`: 使用 `PyConfig.isolated`

  - `Py_LegacyWindowsFSEncodingFlag`: 使用 `PyPreConfig.legacy_windows_fs_encoding`

  - `Py_LegacyWindowsStdioFlag`: 使用 `PyConfig.legacy_windows_stdio`

  - `Py_FileSystemDefaultEncoding`: 使用 `PyConfig.filesystem_encoding`

  - `Py_HasFileSystemDefaultEncoding`: 使用 `PyConfig.filesystem_encoding`

  - `Py_FileSystemDefaultEncodeErrors`: 使用 `PyConfig.filesystem_errors`

  - `Py_UTF8Mode`: 使用 `PyPreConfig.utf8_mode` (参见 `Py_PreInitialize()`)

  `Py_InitializeFromConfig()` API 应与 `PyConfig` 一起使用。

### Python 3.15 中的待移除功能

- 捆绑的 `libmpdecimal` 副本。

- `PyImport_ImportModuleNoBlock()`: 使用 `PyImport_ImportModule()`。

- `PyWeakref_GET_OBJECT()`: 改用 `PyWeakref_GetRef()`。

- `PyWeakref_GetObject()`: 改用 `PyWeakref_GetRef()`。

- `Py_UNICODE_WIDE` 类型：改用 `wchar_t`。

- `Py_UNICODE` 类型：改用 `wchar_t`。

- Python 初始化函数

  - `PySys_ResetWarnOptions()`: clear `sys.warnoptions` and `warnings.filters` instead.

  - `Py_GetExecPrefix()`: get `sys.exec_prefix` instead.

  - `Py_GetPath()`: get `sys.path` instead.

  - `Py_GetPrefix()`: get `sys.prefix` instead.

  - `Py_GetProgramFullPath()`: get `sys.executable` instead.

  - `Py_GetProgramName()`: get `sys.executable` instead.

  - `Py_GetPythonHome()`: get `PyConfig.home` or `PYTHONHOME` environment variable instead.

### 计划在未来版本中移除

下列 API 在更早的 Python 版本中已被弃用并将被移除，但目前还没有确定它们的移除日期。

- `Py_TPFLAGS_HAVE_FINALIZE`: 自 Python 3.8 起不再需要。

- `PyErr_Fetch()`: 使用 `PyErr_GetRaisedException()`。

- `PyErr_NormalizeException()`: 使用 `PyErr_GetRaisedException()`。

- `PyErr_Restore()`: 使用 `PyErr_SetRaisedException()`。

- `PyModule_GetFilename()`: 使用 `PyModule_GetFilenameObject()`。

- `PyOS_AfterFork()`: 使用 `PyOS_AfterFork_Child()`。

- `PySlice_GetIndicesEx()`。

- `PyUnicode_AsDecodedObject()`。

- `PyUnicode_AsDecodedUnicode()`。

- `PyUnicode_AsEncodedObject()`。

- `PyUnicode_AsEncodedUnicode()`。

- `PyUnicode_READY()`: 自 Python 3.12 起不再需要。

- `_PyErr_ChainExceptions()`。

- `PyBytesObject.ob_shash` 成员：改为调用 `PyObject_Hash()`。

- `PyDictObject.ma_version_tag` 成员。

- TLS API：

  - `PyThread_create_key()`: 使用 `PyThread_tss_alloc()`。

  - `PyThread_delete_key()`: 使用 `PyThread_tss_free()`。

  - `PyThread_set_key_value()`: 使用 `PyThread_tss_set()`。

  - `PyThread_get_key_value()`: 使用 `PyThread_tss_get()`。

  - `PyThread_delete_key_value()`: 使用 `PyThread_tss_delete()`。

  - `PyThread_ReInitTLS()`: 不再需要。

- 从受限 C API 移除了未写入文档的 `PY_TIMEOUT_MAX` 常量。 （由 Victor Stinner 在 gh-110014 中贡献。）

## 回归测试的变化

- 现在使用 `configure` `--with-pydebug` 编译的 Python 将支持 `-X presite=package.module` 命令行选项。 如果被使用，它指明一个模块应当在解释器生命周期开始时，即 `site.py` 被执行之前被导入。 （由 Łukasz Langa 在 gh-110769 中贡献。）