python_doc_md/Beginner/whatsnew/3.12.md

# What\'s New In Python 3.12

Editor
:   Adam Turner

> \* Anyone can add text to this document. Do not spend very much time on the wording of your changes, because your text will probably get rewritten to some degree.
>
> \* The maintainer will go through Misc/NEWS periodically and add changes; it\'s therefore more important to add your changes to Misc/NEWS than to this file.
>
> \* This is not a complete list of every single change; completeness is the purpose of Misc/NEWS. Some changes I consider too small or esoteric to include. If such a change is added to the text, I\'ll just remove it. (This is another reason you shouldn\'t spend too much time on writing your addition.)
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> XXX Describe the transmogrify() function added to the socket module. (Contributed by P.Y. Developer in `12345`{.interpreted-text role="gh"}.)
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> This saves the maintainer the effort of going through the VCS log when researching a change.

This article explains the new features in Python 3.12, compared to 3.11. Python 3.12 was released on October 2, 2023. For full details, see the `changelog <changelog>`{.interpreted-text role="ref"}.

::: seealso
`693`{.interpreted-text role="pep"} \-- Python 3.12 Release Schedule
:::

## Summary \-- Release highlights

Python 3.12 is a stable release of the Python programming language, with a mix of changes to the language and the standard library. The library changes focus on cleaning up deprecated APIs, usability, and correctness. Of note, the `!distutils`{.interpreted-text role="mod"} package has been removed from the standard library. Filesystem support in `os`{.interpreted-text role="mod"} and `pathlib`{.interpreted-text role="mod"} has seen a number of improvements, and several modules have better performance.

The language changes focus on usability, as `f-strings <f-string>`{.interpreted-text role="term"} have had many limitations removed and \'Did you mean \...\' suggestions continue to improve. The new `type parameter syntax <whatsnew312-pep695>`{.interpreted-text role="ref"} and `type`{.interpreted-text role="keyword"} statement improve ergonomics for using `generic types
<generic type>`{.interpreted-text role="term"} and `type aliases <type alias>`{.interpreted-text role="term"} with static type checkers.

This article doesn\'t attempt to provide a complete specification of all new features, but instead gives a convenient overview. For full details, you should refer to the documentation, such as the `Library Reference <library-index>`{.interpreted-text role="ref"} and `Language Reference <reference-index>`{.interpreted-text role="ref"}. If you want to understand the complete implementation and design rationale for a change, refer to the PEP for a particular new feature; but note that PEPs usually are not kept up-to-date once a feature has been fully implemented.

------------------------------------------------------------------------

New syntax features:

- `PEP 695 <whatsnew312-pep695>`{.interpreted-text role="ref"}, type parameter syntax and the `type`{.interpreted-text role="keyword"} statement

New grammar features:

- `PEP 701 <whatsnew312-pep701>`{.interpreted-text role="ref"}, `f-strings <f-string>`{.interpreted-text role="term"} in the grammar

Interpreter improvements:

- `PEP 684 <whatsnew312-pep684>`{.interpreted-text role="ref"}, a unique per-interpreter `GIL
  <global interpreter lock>`{.interpreted-text role="term"}
- `PEP 669 <whatsnew312-pep669>`{.interpreted-text role="ref"}, low impact monitoring
- [Improved \'Did you mean \...\' suggestions](#improved-error-messages) for `NameError`{.interpreted-text role="exc"}, `ImportError`{.interpreted-text role="exc"}, and `SyntaxError`{.interpreted-text role="exc"} exceptions

Python data model improvements:

- `PEP 688 <whatsnew312-pep688>`{.interpreted-text role="ref"}, using the `buffer protocol
  <bufferobjects>`{.interpreted-text role="ref"} from Python

Significant improvements in the standard library:

- The `pathlib.Path`{.interpreted-text role="class"} class now supports subclassing
- The `os`{.interpreted-text role="mod"} module received several improvements for Windows support
- A `command-line interface <sqlite3-cli>`{.interpreted-text role="ref"} has been added to the `sqlite3`{.interpreted-text role="mod"} module
- `isinstance`{.interpreted-text role="func"} checks against `runtime-checkable protocols
  <typing.runtime_checkable>`{.interpreted-text role="func"} enjoy a speed up of between two and 20 times
- The `asyncio`{.interpreted-text role="mod"} package has had a number of performance improvements, with some benchmarks showing a 75% speed up.
- A `command-line interface <uuid-cli>`{.interpreted-text role="ref"} has been added to the `uuid`{.interpreted-text role="mod"} module
- Due to the changes in `PEP 701 <whatsnew312-pep701>`{.interpreted-text role="ref"}, producing tokens via the `tokenize`{.interpreted-text role="mod"} module is up to 64% faster.

Security improvements:

- Replace the builtin `hashlib`{.interpreted-text role="mod"} implementations of SHA1, SHA3, SHA2-384, SHA2-512, and MD5 with formally verified code from the [HACL\*](https://github.com/hacl-star/hacl-star/) project. These builtin implementations remain as fallbacks that are only used when OpenSSL does not provide them.

C API improvements:

- `PEP 697 <whatsnew312-pep697>`{.interpreted-text role="ref"}, unstable C API tier
- `PEP 683 <whatsnew312-pep683>`{.interpreted-text role="ref"}, immortal objects

CPython implementation improvements:

- `PEP 709 <whatsnew312-pep709>`{.interpreted-text role="ref"}, comprehension inlining
- `CPython support <perf_profiling>`{.interpreted-text role="ref"} for the Linux `perf` profiler
- Implement stack overflow protection on supported platforms

New typing features:

- `PEP 692 <whatsnew312-pep692>`{.interpreted-text role="ref"}, using `~typing.TypedDict`{.interpreted-text role="class"} to annotate `**kwargs <argument>`{.interpreted-text role="term"}
- `PEP 698 <whatsnew312-pep698>`{.interpreted-text role="ref"}, `typing.override`{.interpreted-text role="func"} decorator

Important deprecations, removals or restrictions:

- `623`{.interpreted-text role="pep"}: Remove `wstr` from Unicode objects in Python\'s C API, reducing the size of every `str`{.interpreted-text role="class"} object by at least 8 bytes.
- `632`{.interpreted-text role="pep"}: Remove the `!distutils`{.interpreted-text role="mod"} package. See `the migration guide <0632#migration-advice>`{.interpreted-text role="pep"} for advice replacing the APIs it provided. The third-party [Setuptools](https://setuptools.pypa.io/en/latest/deprecated/distutils-legacy.html) package continues to provide `!distutils`{.interpreted-text role="mod"}, if you still require it in Python 3.12 and beyond.
- `95299`{.interpreted-text role="gh"}: Do not pre-install `setuptools` in virtual environments created with `venv`{.interpreted-text role="mod"}. This means that `distutils`, `setuptools`, `pkg_resources`, and `easy_install` will no longer available by default; to access these run `pip install setuptools` in the `activated <venv-explanation>`{.interpreted-text role="ref"} virtual environment.
- The `!asynchat`{.interpreted-text role="mod"}, `!asyncore`{.interpreted-text role="mod"}, and `!imp`{.interpreted-text role="mod"} modules have been removed, along with several `unittest.TestCase`{.interpreted-text role="class"} [method aliases](#unittest-TestCase-removed-aliases).

## New Features

### PEP 695: Type Parameter Syntax {#whatsnew312-pep695}

Generic classes and functions under `484`{.interpreted-text role="pep"} were declared using a verbose syntax that left the scope of type parameters unclear and required explicit declarations of variance.

`695`{.interpreted-text role="pep"} introduces a new, more compact and explicit way to create `generic classes <generic-classes>`{.interpreted-text role="ref"} and `functions <generic-functions>`{.interpreted-text role="ref"}:

    def max[T](args: Iterable[T]) -> T:
        ...

    class list[T]:
        def __getitem__(self, index: int, /) -> T:
            ...

        def append(self, element: T) -> None:
            ...

In addition, the PEP introduces a new way to declare `type aliases <type-aliases>`{.interpreted-text role="ref"} using the `type`{.interpreted-text role="keyword"} statement, which creates an instance of `~typing.TypeAliasType`{.interpreted-text role="class"}:

    type Point = tuple[float, float]

Type aliases can also be `generic <generic-type-aliases>`{.interpreted-text role="ref"}:

    type Point[T] = tuple[T, T]

The new syntax allows declaring `~typing.TypeVarTuple`{.interpreted-text role="class"} and `~typing.ParamSpec`{.interpreted-text role="class"} parameters, as well as `~typing.TypeVar`{.interpreted-text role="class"} parameters with bounds or constraints:

    type IntFunc[**P] = Callable[P, int]  # ParamSpec
    type LabeledTuple[*Ts] = tuple[str, *Ts]  # TypeVarTuple
    type HashableSequence[T: Hashable] = Sequence[T]  # TypeVar with bound
    type IntOrStrSequence[T: (int, str)] = Sequence[T]  # TypeVar with constraints

The value of type aliases and the bound and constraints of type variables created through this syntax are evaluated only on demand (see `lazy evaluation <lazy-evaluation>`{.interpreted-text role="ref"}). This means type aliases are able to refer to other types defined later in the file.

Type parameters declared through a type parameter list are visible within the scope of the declaration and any nested scopes, but not in the outer scope. For example, they can be used in the type annotations for the methods of a generic class or in the class body. However, they cannot be used in the module scope after the class is defined. See `type-params`{.interpreted-text role="ref"} for a detailed description of the runtime semantics of type parameters.

In order to support these scoping semantics, a new kind of scope is introduced, the `annotation scope <annotation-scopes>`{.interpreted-text role="ref"}. Annotation scopes behave for the most part like function scopes, but interact differently with enclosing class scopes. In Python 3.13, `annotations <annotation>`{.interpreted-text role="term"} will also be evaluated in annotation scopes.

See `695`{.interpreted-text role="pep"} for more details.

(PEP written by Eric Traut. Implementation by Jelle Zijlstra, Eric Traut, and others in `103764`{.interpreted-text role="gh"}.)

### PEP 701: Syntactic formalization of f-strings {#whatsnew312-pep701}

`701`{.interpreted-text role="pep"} lifts some restrictions on the usage of `f-strings <f-string>`{.interpreted-text role="term"}. 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-string raises a `SyntaxError`{.interpreted-text role="exc"}, forcing the user to either use other available quotes (like using double quotes or triple quotes if the f-string uses single quotes). 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 can be nested, but the fact that string quotes cannot be reused inside the expression component of f-strings made it impossible to nest f-strings arbitrarily. 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 expression components, 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 expressions must be defined in a single line, even if the expression within the f-string could 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-strings spanning 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 expressions couldn\'t contain any `\` character. This also affected unicode `escape
  sequences <escape-sequences>`{.interpreted-text role="ref"} (such as `\N{snowman}`) as these contain the `\N` part that previously could not be part of expression components of f-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 Eden Alkaline Ascensionism \>\>\> print(f\"This is the playlist: {\"N{BLACK HEART SUIT}\".join(songs)}\") This is the playlist: Take me back to Eden♥Alkaline♥Ascensionism

See `701`{.interpreted-text role="pep"} for more details.

As a positive side-effect of how this feature has been implemented (by parsing f-strings with `the PEG parser <617>`{.interpreted-text role="pep"}), now error messages for f-strings are more precise and include the exact location of the error. For example, in Python 3.11, the following f-string raises a `SyntaxError`{.interpreted-text role="exc"}:

``` python
>>> my_string = f"{x z y}" + f"{1 + 1}"
  File "<stdin>", line 1
    (x z y)
     ^^^
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 and also has the expression artificially surrounded by parentheses. In Python 3.12, as f-strings are parsed with the PEG parser, error messages can be more precise and show the entire line:

``` python
>>> my_string = f"{x z y}" + f"{1 + 1}"
  File "<stdin>", line 1
    my_string = f"{x z y}" + f"{1 + 1}"
                   ^^^
SyntaxError: invalid syntax. Perhaps you forgot a comma?
```

(Contributed by Pablo Galindo, Batuhan Taskaya, Lysandros Nikolaou, Cristián Maureira-Fredes and Marta Gómez in `102856`{.interpreted-text role="gh"}. PEP written by Pablo Galindo, Batuhan Taskaya, Lysandros Nikolaou and Marta Gómez).

### PEP 684: A Per-Interpreter GIL {#whatsnew312-pep684}

`684`{.interpreted-text role="pep"} introduces a per-interpreter `GIL <global interpreter lock>`{.interpreted-text role="term"}, so that sub-interpreters may now be created with a unique GIL per interpreter. This allows Python programs to take full advantage of multiple CPU cores. This is currently only available through the C-API, though a Python API is `anticipated for 3.13 <554>`{.interpreted-text role="pep"}.

Use the new `Py_NewInterpreterFromConfig`{.interpreted-text role="c:func"} function to create an interpreter with its own GIL:

``` c
PyInterpreterConfig config = {
    .check_multi_interp_extensions = 1,
    .gil = PyInterpreterConfig_OWN_GIL,
};
PyThreadState *tstate = NULL;
PyStatus status = Py_NewInterpreterFromConfig(&tstate, &config);
if (PyStatus_Exception(status)) {
    return -1;
}
/* The new interpreter is now active in the current thread. */
```

For further examples how to use the C-API for sub-interpreters with a per-interpreter GIL, see `Modules/_xxsubinterpretersmodule.c`.

(Contributed by Eric Snow in `104210`{.interpreted-text role="gh"}, etc.)

### PEP 669: Low impact monitoring for CPython {#whatsnew312-pep669}

`669`{.interpreted-text role="pep"} defines a new `API <sys.monitoring>`{.interpreted-text role="mod"} 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 support for near-zero overhead debuggers and coverage tools. See `sys.monitoring`{.interpreted-text role="mod"} for details.

(Contributed by Mark Shannon in `103082`{.interpreted-text role="gh"}.)

### PEP 688: Making the buffer protocol accessible in Python {#whatsnew312-pep688}

`688`{.interpreted-text role="pep"} introduces a way to use the `buffer protocol <bufferobjects>`{.interpreted-text role="ref"} from Python code. Classes that implement the `~object.__buffer__`{.interpreted-text role="meth"} method are now usable as buffer types.

The new `collections.abc.Buffer`{.interpreted-text role="class"} ABC provides a standard way to represent buffer objects, for example in type annotations. The new `inspect.BufferFlags`{.interpreted-text role="class"} enum represents the flags that can be used to customize buffer creation. (Contributed by Jelle Zijlstra in `102500`{.interpreted-text role="gh"}.)

### PEP 709: Comprehension inlining {#whatsnew312-pep709}

Dictionary, list, and set comprehensions are now inlined, rather than creating a new single-use function object for each execution of the comprehension. This speeds up execution of a comprehension by up to two times. See `709`{.interpreted-text role="pep"} for further details.

Comprehension iteration variables remain isolated and don\'t overwrite a variable of the same name in the outer scope, nor are they visible after the comprehension. 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.
- The `symtable`{.interpreted-text role="mod"} module will no longer produce child symbol tables for each comprehension; instead, the comprehension\'s locals will be included in the parent function\'s symbol table.
- Calling `locals`{.interpreted-text role="func"} inside a comprehension now includes variables from outside the comprehension, and no longer includes the synthetic `.0` variable for the comprehension \"argument\".
- A comprehension iterating directly over `locals()` (e.g. `[k for k in locals()]`) may see \"RuntimeError: dictionary changed size during iteration\" when run under tracing (e.g. code coverage measurement). This is the same behavior already seen in e.g. `for k in locals():`. To avoid the error, first create a list of keys to iterate over: `keys = list(locals()); [k for k in keys]`.

(Contributed by Carl Meyer and Vladimir Matveev in `709`{.interpreted-text role="pep"}.)

### Improved Error Messages

- Modules from the standard library are now potentially suggested as part of the error messages displayed by the interpreter when a `NameError`{.interpreted-text role="exc"} is raised to the top level. (Contributed by Pablo Galindo in `98254`{.interpreted-text role="gh"}.)

  > \>\>\> sys.version_info Traceback (most recent call last): File \"\<stdin\>\", line 1, in \<module\> NameError: name \'sys\' is not defined. Did you forget to import \'sys\'?

- Improve the error suggestion for `NameError`{.interpreted-text role="exc"} exceptions for instances. Now if a `NameError`{.interpreted-text role="exc"} is raised in a method and the instance has an attribute that\'s exactly equal to the name in the exception, the suggestion will include `self.<NAME>` instead of the closest match in the method scope. (Contributed by Pablo Galindo in `99139`{.interpreted-text role="gh"}.)

  > \>\>\> class A: \... def \_\_init\_\_(self): \... self.blech = 1 \... \... def foo(self): \... somethin = blech \... \>\>\> A().foo() Traceback (most recent call last): File \"\<stdin\>\", line 1 somethin = blech \^\^\^\^\^ NameError: name \'blech\' is not defined. Did you mean: \'self.blech\'?

- Improve the `SyntaxError`{.interpreted-text role="exc"} error message when the user types `import x from y` instead of `from y import x`. (Contributed by Pablo Galindo in `98931`{.interpreted-text role="gh"}.)

  > \>\>\> import a.y.z from b.y.z Traceback (most recent call last): File \"\<stdin\>\", line 1 import a.y.z from b.y.z \^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^\^ SyntaxError: Did you mean to use \'from \... import \...\' instead?

- `ImportError`{.interpreted-text role="exc"} exceptions raised from failed `from <module> import <name>` statements now include suggestions for the value of `<name>` based on the available names in `<module>`. (Contributed by Pablo Galindo in `91058`{.interpreted-text role="gh"}.)

  > \>\>\> from collections import chainmap Traceback (most recent call last): File \"\<stdin\>\", line 1, in \<module\> ImportError: cannot import name \'chainmap\' from \'collections\'. Did you mean: \'ChainMap\'?

## New Features Related to Type Hints

This section covers major changes affecting `type hints <484>`{.interpreted-text role="pep"} and the `typing`{.interpreted-text role="mod"} module.

### PEP 692: Using `TypedDict` for more precise `**kwargs` typing {#whatsnew312-pep692}

Typing `**kwargs` in a function signature as introduced by `484`{.interpreted-text role="pep"} allowed for valid annotations only in cases where all of the `**kwargs` were of the same type.

`692`{.interpreted-text role="pep"} specifies a more precise way of typing `**kwargs` by relying on typed dictionaries:

    from typing import TypedDict, Unpack

    class Movie(TypedDict):
      name: str
      year: int

    def foo(**kwargs: Unpack[Movie]): ...

See `692`{.interpreted-text role="pep"} for more details.

(Contributed by Franek Magiera in `103629`{.interpreted-text role="gh"}.)

### PEP 698: Override Decorator for Static Typing {#whatsnew312-pep698}

A new decorator `typing.override`{.interpreted-text role="func"} has been added to the `typing`{.interpreted-text role="mod"} module. It indicates to type checkers that the method is intended to override a method in a superclass. This allows type checkers to catch mistakes where a method that is intended to override something in a base class does not in fact do so.

Example:

    from typing import override

    class Base:
      def get_color(self) -> str:
        return "blue"

    class GoodChild(Base):
      @override  # ok: overrides Base.get_color
      def get_color(self) -> str:
        return "yellow"

    class BadChild(Base):
      @override  # type checker error: does not override Base.get_color
      def get_colour(self) -> str:
        return "red"

See `698`{.interpreted-text role="pep"} for more details.

(Contributed by Steven Troxler in `101561`{.interpreted-text role="gh"}.)

## Other Language Changes

- The parser now raises `SyntaxError`{.interpreted-text role="exc"} when parsing source code containing null bytes. (Contributed by Pablo Galindo in `96670`{.interpreted-text role="gh"}.)
- A backslash-character pair that is not a valid escape sequence now generates a `SyntaxWarning`{.interpreted-text role="exc"}, instead of `DeprecationWarning`{.interpreted-text role="exc"}. For example, `re.compile("\d+\.\d+")` now emits a `SyntaxWarning`{.interpreted-text role="exc"} (`"\d"` is an invalid escape sequence, use raw strings for regular expression: `re.compile(r"\d+\.\d+")`). In a future Python version, `SyntaxError`{.interpreted-text role="exc"} will eventually be raised, instead of `SyntaxWarning`{.interpreted-text role="exc"}. (Contributed by Victor Stinner in `98401`{.interpreted-text role="gh"}.)
- Octal escapes with value larger than `0o377` (ex: `"\477"`), deprecated in Python 3.11, now produce a `SyntaxWarning`{.interpreted-text role="exc"}, instead of `DeprecationWarning`{.interpreted-text role="exc"}. In a future Python version they will be eventually a `SyntaxError`{.interpreted-text role="exc"}. (Contributed by Victor Stinner in `98401`{.interpreted-text role="gh"}.)
- Variables used in the target part of comprehensions that are not stored to can now be used in assignment expressions (`:=`). For example, in `[(b := 1) for a, b.prop in some_iter]`, the assignment to `b` is now allowed. Note that assigning to variables stored to in the target part of comprehensions (like `a`) is still disallowed, as per `572`{.interpreted-text role="pep"}. (Contributed by Nikita Sobolev in `100581`{.interpreted-text role="gh"}.)
- Exceptions raised in a class or type\'s `__set_name__` method are no longer wrapped by a `RuntimeError`{.interpreted-text role="exc"}. Context information is added to the exception as a `678`{.interpreted-text role="pep"} note. (Contributed by Irit Katriel in `77757`{.interpreted-text role="gh"}.)
- When a `try-except*` construct handles the entire `ExceptionGroup`{.interpreted-text role="exc"} and raises one other exception, that exception is no longer wrapped in an `ExceptionGroup`{.interpreted-text role="exc"}. Also changed in version 3.11.4. (Contributed by Irit Katriel in `103590`{.interpreted-text role="gh"}.)
- The Garbage Collector now runs only on the eval breaker mechanism of the Python bytecode evaluation loop instead of object allocations. The GC can also run when `PyErr_CheckSignals`{.interpreted-text role="c:func"} is called so C extensions that need to run for a long time without executing any Python code also have a chance to execute the GC periodically. (Contributed by Pablo Galindo in `97922`{.interpreted-text role="gh"}.)
- All builtin and extension callables expecting boolean parameters now accept arguments of any type instead of just `bool`{.interpreted-text role="class"} and `int`{.interpreted-text role="class"}. (Contributed by Serhiy Storchaka in `60203`{.interpreted-text role="gh"}.)
- `memoryview`{.interpreted-text role="class"} now supports the half-float type (the \"e\" format code). (Contributed by Donghee Na and Antoine Pitrou in `90751`{.interpreted-text role="gh"}.)
- `slice`{.interpreted-text role="class"} objects are now hashable, allowing them to be used as dict keys and set items. (Contributed by Will Bradshaw, Furkan Onder, and Raymond Hettinger in `101264`{.interpreted-text role="gh"}.)
- `sum`{.interpreted-text role="func"} now uses Neumaier summation to improve accuracy and commutativity when summing floats or mixed ints and floats. (Contributed by Raymond Hettinger in `100425`{.interpreted-text role="gh"}.)
- `ast.parse`{.interpreted-text role="func"} now raises `SyntaxError`{.interpreted-text role="exc"} instead of `ValueError`{.interpreted-text role="exc"} when parsing source code containing null bytes. (Contributed by Pablo Galindo in `96670`{.interpreted-text role="gh"}.)
- The extraction methods in `tarfile`{.interpreted-text role="mod"}, and `shutil.unpack_archive`{.interpreted-text role="func"}, have a new a *filter* argument that allows limiting tar features than may be surprising or dangerous, such as creating files outside the destination directory. See `tarfile extraction filters <tarfile-extraction-filter>`{.interpreted-text role="ref"} for details. In Python 3.14, the default will switch to `'data'`. (Contributed by Petr Viktorin in `706`{.interpreted-text role="pep"}.)
- `types.MappingProxyType`{.interpreted-text role="class"} instances are now hashable if the underlying mapping is hashable. (Contributed by Serhiy Storchaka in `87995`{.interpreted-text role="gh"}.)
- Add `support for the perf profiler <perf_profiling>`{.interpreted-text role="ref"} through the new environment variable `PYTHONPERFSUPPORT`{.interpreted-text role="envvar"} and command-line option `-X perf <-X>`{.interpreted-text role="option"}, as well as the new `sys.activate_stack_trampoline`{.interpreted-text role="func"}, `sys.deactivate_stack_trampoline`{.interpreted-text role="func"}, and `sys.is_stack_trampoline_active`{.interpreted-text role="func"} functions. (Design by Pablo Galindo. Contributed by Pablo Galindo and Christian Heimes with contributions from Gregory P. Smith \[Google\] and Mark Shannon in `96123`{.interpreted-text role="gh"}.)

## New Modules

- None.

## Improved Modules

### array

- The `array.array`{.interpreted-text role="class"} class now supports subscripting, making it a `generic type`{.interpreted-text role="term"}. (Contributed by Jelle Zijlstra in `98658`{.interpreted-text role="gh"}.)

### asyncio

- The performance of writing to sockets in `asyncio`{.interpreted-text role="mod"} has been significantly improved. `asyncio` now avoids unnecessary copying when writing to sockets and uses `~socket.socket.sendmsg`{.interpreted-text role="meth"} if the platform supports it. (Contributed by Kumar Aditya in `91166`{.interpreted-text role="gh"}.)
- Add `asyncio.eager_task_factory`{.interpreted-text role="func"} and `asyncio.create_eager_task_factory`{.interpreted-text role="func"} functions to allow opting an event loop in to eager task execution, making some use-cases 2x to 5x faster. (Contributed by Jacob Bower & Itamar Oren in `102853`{.interpreted-text role="gh"}, `104140`{.interpreted-text role="gh"}, and `104138`{.interpreted-text role="gh"})
- On Linux, `asyncio`{.interpreted-text role="mod"} uses `!asyncio.PidfdChildWatcher`{.interpreted-text role="class"} by default if `os.pidfd_open`{.interpreted-text role="func"} is available and functional instead of `!asyncio.ThreadedChildWatcher`{.interpreted-text role="class"}. (Contributed by Kumar Aditya in `98024`{.interpreted-text role="gh"}.)
- The event loop now uses the best available child watcher for each platform (`!asyncio.PidfdChildWatcher`{.interpreted-text role="class"} if supported and `!asyncio.ThreadedChildWatcher`{.interpreted-text role="class"} otherwise), so manually configuring a child watcher is not recommended. (Contributed by Kumar Aditya in `94597`{.interpreted-text role="gh"}.)
- Add *loop_factory* parameter to `asyncio.run`{.interpreted-text role="func"} to allow specifying a custom event loop factory. (Contributed by Kumar Aditya in `99388`{.interpreted-text role="gh"}.)
- Add C implementation of `asyncio.current_task`{.interpreted-text role="func"} for 4x-6x speedup. (Contributed by Itamar Oren and Pranav Thulasiram Bhat in `100344`{.interpreted-text role="gh"}.)
- `asyncio.iscoroutine`{.interpreted-text role="func"} now returns `False` for generators as `asyncio`{.interpreted-text role="mod"} does not support legacy generator-based coroutines. (Contributed by Kumar Aditya in `102748`{.interpreted-text role="gh"}.)
- `asyncio.wait`{.interpreted-text role="func"} and `asyncio.as_completed`{.interpreted-text role="func"} now accepts generators yielding tasks. (Contributed by Kumar Aditya in `78530`{.interpreted-text role="gh"}.)

### calendar

- Add enums `calendar.Month`{.interpreted-text role="data"} and `calendar.Day`{.interpreted-text role="data"} defining months of the year and days of the week. (Contributed by Prince Roshan in `103636`{.interpreted-text role="gh"}.)

### csv

- Add `csv.QUOTE_NOTNULL`{.interpreted-text role="const"} and `csv.QUOTE_STRINGS`{.interpreted-text role="const"} flags to provide finer grained control of `None` and empty strings by `~csv.reader`{.interpreted-text role="class"} and `~csv.writer`{.interpreted-text role="class"} objects.

### dis

- Pseudo instruction opcodes (which are used by the compiler but do not appear in executable bytecode) are now exposed in the `dis`{.interpreted-text role="mod"} module. `HAVE_ARGUMENT`{.interpreted-text role="opcode"} is still relevant to real opcodes, but it is not useful for pseudo instructions. Use the new `dis.hasarg`{.interpreted-text role="data"} collection instead. (Contributed by Irit Katriel in `94216`{.interpreted-text role="gh"}.)
- Add the `dis.hasexc`{.interpreted-text role="data"} collection to signify instructions that set an exception handler. (Contributed by Irit Katriel in `94216`{.interpreted-text role="gh"}.)

### fractions

- Objects of type `fractions.Fraction`{.interpreted-text role="class"} now support float-style formatting. (Contributed by Mark Dickinson in `100161`{.interpreted-text role="gh"}.)

### importlib.resources

- `importlib.resources.as_file`{.interpreted-text role="func"} now supports resource directories. (Contributed by Jason R. Coombs in `97930`{.interpreted-text role="gh"}.)
- Rename first parameter of `importlib.resources.files`{.interpreted-text role="func"} to *anchor*. (Contributed by Jason R. Coombs in `100598`{.interpreted-text role="gh"}.)

### inspect

- Add `inspect.markcoroutinefunction`{.interpreted-text role="func"} to mark sync functions that return a `coroutine`{.interpreted-text role="term"} for use with `inspect.iscoroutinefunction`{.interpreted-text role="func"}. (Contributed by Carlton Gibson in `99247`{.interpreted-text role="gh"}.)
- Add `inspect.getasyncgenstate`{.interpreted-text role="func"} and `inspect.getasyncgenlocals`{.interpreted-text role="func"} for determining the current state of asynchronous generators. (Contributed by Thomas Krennwallner in `79940`{.interpreted-text role="gh"}.)
- The performance of `inspect.getattr_static`{.interpreted-text role="func"} has been considerably improved. Most calls to the function should be at least 2x faster than they were in Python 3.11. (Contributed by Alex Waygood in `103193`{.interpreted-text role="gh"}.)

### itertools

- Add `itertools.batched`{.interpreted-text role="func"} for collecting into even-sized tuples where the last batch may be shorter than the rest. (Contributed by Raymond Hettinger in `98363`{.interpreted-text role="gh"}.)

### math

- Add `math.sumprod`{.interpreted-text role="func"} for computing a sum of products. (Contributed by Raymond Hettinger in `100485`{.interpreted-text role="gh"}.)
- Extend `math.nextafter`{.interpreted-text role="func"} to include a *steps* argument for moving up or down multiple steps at a time. (Contributed by Matthias Goergens, Mark Dickinson, and Raymond Hettinger in `94906`{.interpreted-text role="gh"}.)

### os

- Add `os.PIDFD_NONBLOCK`{.interpreted-text role="const"} to open a file descriptor for a process with `os.pidfd_open`{.interpreted-text role="func"} in non-blocking mode. (Contributed by Kumar Aditya in `93312`{.interpreted-text role="gh"}.)
- `os.DirEntry`{.interpreted-text role="class"} now includes an `os.DirEntry.is_junction`{.interpreted-text role="meth"} method to check if the entry is a junction. (Contributed by Charles Machalow in `99547`{.interpreted-text role="gh"}.)
- Add `os.listdrives`{.interpreted-text role="func"}, `os.listvolumes`{.interpreted-text role="func"} and `os.listmounts`{.interpreted-text role="func"} functions on Windows for enumerating drives, volumes and mount points. (Contributed by Steve Dower in `102519`{.interpreted-text role="gh"}.)
- `os.stat`{.interpreted-text role="func"} and `os.lstat`{.interpreted-text role="func"} are now more accurate on Windows. The `st_birthtime` field will now be filled with the creation time of the file, and `st_ctime` is deprecated but still contains the creation time (but in the future will return the last metadata change, for consistency with other platforms). `st_dev` may be up to 64 bits and `st_ino` up to 128 bits depending on your file system, and `st_rdev` is always set to zero rather than incorrect values. Both functions may be significantly faster on newer releases of Windows. (Contributed by Steve Dower in `99726`{.interpreted-text role="gh"}.)

### os.path

- Add `os.path.isjunction`{.interpreted-text role="func"} to check if a given path is a junction. (Contributed by Charles Machalow in `99547`{.interpreted-text role="gh"}.)
- Add `os.path.splitroot`{.interpreted-text role="func"} to split a path into a triad `(drive, root, tail)`. (Contributed by Barney Gale in `101000`{.interpreted-text role="gh"}.)

### pathlib

- Add support for subclassing `pathlib.PurePath`{.interpreted-text role="class"} and `pathlib.Path`{.interpreted-text role="class"}, plus their Posix- and Windows-specific variants. Subclasses may override the `pathlib.PurePath.with_segments`{.interpreted-text role="meth"} method to pass information between path instances.
- Add `pathlib.Path.walk`{.interpreted-text role="meth"} for walking the directory trees and generating all file or directory names within them, similar to `os.walk`{.interpreted-text role="func"}. (Contributed by Stanislav Zmiev in `90385`{.interpreted-text role="gh"}.)
- Add *walk_up* optional parameter to `pathlib.PurePath.relative_to`{.interpreted-text role="meth"} to allow the insertion of `..` entries in the result; this behavior is more consistent with `os.path.relpath`{.interpreted-text role="func"}. (Contributed by Domenico Ragusa in `84538`{.interpreted-text role="gh"}.)
- Add `pathlib.Path.is_junction`{.interpreted-text role="meth"} as a proxy to `os.path.isjunction`{.interpreted-text role="func"}. (Contributed by Charles Machalow in `99547`{.interpreted-text role="gh"}.)
- Add *case_sensitive* optional parameter to `pathlib.Path.glob`{.interpreted-text role="meth"}, `pathlib.Path.rglob`{.interpreted-text role="meth"} and `pathlib.PurePath.match`{.interpreted-text role="meth"} for matching the path\'s case sensitivity, allowing for more precise control over the matching process.

### platform

- Add support for detecting Windows 11 and Windows Server releases past 2012. Previously, lookups on Windows Server platforms newer than Windows Server 2012 and on Windows 11 would return `Windows-10`. (Contributed by Steve Dower in `89545`{.interpreted-text role="gh"}.)

### pdb

- Add convenience variables to hold values temporarily for debug session and provide quick access to values like the current frame or the return value. (Contributed by Tian Gao in `103693`{.interpreted-text role="gh"}.)

### random

- Add `random.binomialvariate`{.interpreted-text role="func"}. (Contributed by Raymond Hettinger in `81620`{.interpreted-text role="gh"}.)
- Add a default of `lambd=1.0` to `random.expovariate`{.interpreted-text role="func"}. (Contributed by Raymond Hettinger in `100234`{.interpreted-text role="gh"}.)

### shutil

- `shutil.make_archive`{.interpreted-text role="func"} now passes the *root_dir* argument to custom archivers which support it. In this case it no longer temporarily changes the current working directory of the process to *root_dir* to perform archiving. (Contributed by Serhiy Storchaka in `74696`{.interpreted-text role="gh"}.)

- `shutil.rmtree`{.interpreted-text role="func"} now accepts a new argument *onexc* which is an error handler like *onerror* but which expects an exception instance rather than a *(typ, val, tb)* triplet. *onerror* is deprecated. (Contributed by Irit Katriel in `102828`{.interpreted-text role="gh"}.)

- `shutil.which`{.interpreted-text role="func"} now consults the *PATHEXT* environment variable to find matches within *PATH* on Windows even when the given *cmd* includes a directory component. (Contributed by Charles Machalow in `103179`{.interpreted-text role="gh"}.)

  `shutil.which`{.interpreted-text role="func"} will call `NeedCurrentDirectoryForExePathW` when querying for executables on Windows to determine if the current working directory should be prepended to the search path. (Contributed by Charles Machalow in `103179`{.interpreted-text role="gh"}.)

  `shutil.which`{.interpreted-text role="func"} will return a path matching the *cmd* with a component from `PATHEXT` prior to a direct match elsewhere in the search path on Windows. (Contributed by Charles Machalow in `103179`{.interpreted-text role="gh"}.)

### sqlite3

- Add a `command-line interface <sqlite3-cli>`{.interpreted-text role="ref"}. (Contributed by Erlend E. Aasland in `77617`{.interpreted-text role="gh"}.)
- Add the `sqlite3.Connection.autocommit`{.interpreted-text role="attr"} attribute to `sqlite3.Connection`{.interpreted-text role="class"} and the *autocommit* parameter to `sqlite3.connect`{.interpreted-text role="func"} to control `249`{.interpreted-text role="pep"}-compliant `transaction handling <sqlite3-transaction-control-autocommit>`{.interpreted-text role="ref"}. (Contributed by Erlend E. Aasland in `83638`{.interpreted-text role="gh"}.)
- Add *entrypoint* keyword-only parameter to `sqlite3.Connection.load_extension`{.interpreted-text role="meth"}, for overriding the SQLite extension entry point. (Contributed by Erlend E. Aasland in `103015`{.interpreted-text role="gh"}.)
- Add `sqlite3.Connection.getconfig`{.interpreted-text role="meth"} and `sqlite3.Connection.setconfig`{.interpreted-text role="meth"} to `sqlite3.Connection`{.interpreted-text role="class"} to make configuration changes to a database connection. (Contributed by Erlend E. Aasland in `103489`{.interpreted-text role="gh"}.)

### statistics

- Extend `statistics.correlation`{.interpreted-text role="func"} to include as a `ranked` method for computing the Spearman correlation of ranked data. (Contributed by Raymond Hettinger in `95861`{.interpreted-text role="gh"}.)

### sys

- Add the `sys.monitoring`{.interpreted-text role="mod"} namespace to expose the new `PEP 669
  <whatsnew312-pep669>`{.interpreted-text role="ref"} monitoring API. (Contributed by Mark Shannon in `103082`{.interpreted-text role="gh"}.)
- Add `sys.activate_stack_trampoline`{.interpreted-text role="func"} and `sys.deactivate_stack_trampoline`{.interpreted-text role="func"} for activating and deactivating stack profiler trampolines, and `sys.is_stack_trampoline_active`{.interpreted-text role="func"} for querying if stack profiler trampolines are active. (Contributed by Pablo Galindo and Christian Heimes with contributions from Gregory P. Smith \[Google\] and Mark Shannon in `96123`{.interpreted-text role="gh"}.)
- Add `sys.last_exc`{.interpreted-text role="data"} which holds the last unhandled exception that was raised (for post-mortem debugging use cases). Deprecate the three fields that have the same information in its legacy form: `sys.last_type`{.interpreted-text role="data"}, `sys.last_value`{.interpreted-text role="data"} and `sys.last_traceback`{.interpreted-text role="data"}. (Contributed by Irit Katriel in `102778`{.interpreted-text role="gh"}.)
- `sys._current_exceptions`{.interpreted-text role="func"} now returns a mapping from thread-id to an exception instance, rather than to a `(typ, exc, tb)` tuple. (Contributed by Irit Katriel in `103176`{.interpreted-text role="gh"}.)
- `sys.setrecursionlimit`{.interpreted-text role="func"} and `sys.getrecursionlimit`{.interpreted-text role="func"}. The recursion limit now applies only to Python code. Builtin functions do not use the recursion limit, but are protected by a different mechanism that prevents recursion from causing a virtual machine crash.

### tempfile

- The `tempfile.NamedTemporaryFile`{.interpreted-text role="class"} function has a new optional parameter *delete_on_close* (Contributed by Evgeny Zorin in `58451`{.interpreted-text role="gh"}.)
- `tempfile.mkdtemp`{.interpreted-text role="func"} now always returns an absolute path, even if the argument provided to the *dir* parameter is a relative path.

### threading

- Add `threading.settrace_all_threads`{.interpreted-text role="func"} and `threading.setprofile_all_threads`{.interpreted-text role="func"} that allow to set tracing and profiling functions in all running threads in addition to the calling one. (Contributed by Pablo Galindo in `93503`{.interpreted-text role="gh"}.)

### 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), ...]`), like `create_*()` methods. (Contributed by Serhiy Storchaka in `94473`{.interpreted-text role="gh"}.)

### tokenize

- The `tokenize`{.interpreted-text role="mod"} module includes the changes introduced in `701`{.interpreted-text role="pep"}. (Contributed by Marta Gómez Macías and Pablo Galindo in `102856`{.interpreted-text role="gh"}.) See `whatsnew312-porting-to-python312`{.interpreted-text role="ref"} for more information on the changes to the `tokenize`{.interpreted-text role="mod"} module.

### types

- Add `types.get_original_bases`{.interpreted-text role="func"} to allow for further introspection of `user-defined-generics`{.interpreted-text role="ref"} when subclassed. (Contributed by James Hilton-Balfe and Alex Waygood in `101827`{.interpreted-text role="gh"}.)

### typing {#whatsnew-typing-py312}

- `isinstance`{.interpreted-text role="func"} checks against `runtime-checkable protocols <typing.runtime_checkable>`{.interpreted-text role="func"} now use `inspect.getattr_static`{.interpreted-text role="func"} rather than `hasattr`{.interpreted-text role="func"} to lookup whether attributes exist. This means that descriptors and `~object.__getattr__`{.interpreted-text role="meth"} methods are no longer unexpectedly evaluated during `isinstance()` checks against runtime-checkable protocols. However, it may also mean that some objects which used to be considered instances of a runtime-checkable protocol may no longer be considered instances of that protocol on Python 3.12+, and vice versa. Most users are unlikely to be affected by this change. (Contributed by Alex Waygood in `102433`{.interpreted-text role="gh"}.)

- The members of a runtime-checkable protocol are now considered \"frozen\" at runtime as soon as the class has been created. Monkey-patching attributes onto a runtime-checkable protocol will still work, but will have no impact on `isinstance`{.interpreted-text role="func"} checks comparing objects to the protocol. For example:

      >>> from typing import Protocol, runtime_checkable
      >>> @runtime_checkable
      ... class HasX(Protocol):
      ...     x = 1
      ...
      >>> class Foo: ...
      ...
      >>> f = Foo()
      >>> isinstance(f, HasX)
      False
      >>> f.x = 1
      >>> isinstance(f, HasX)
      True
      >>> HasX.y = 2
      >>> isinstance(f, HasX)  # unchanged, even though HasX now also has a "y" attribute
      True

  This change was made in order to speed up `isinstance()` checks against runtime-checkable protocols.

- The performance profile of `isinstance`{.interpreted-text role="func"} checks against `runtime-checkable protocols <typing.runtime_checkable>`{.interpreted-text role="func"} has changed significantly. Most `isinstance()` checks against protocols with only a few members should be at least 2x faster than in 3.11, and some may be 20x faster or more. However, `isinstance()` checks against protocols with many members may be slower than in Python 3.11. (Contributed by Alex Waygood in `74690`{.interpreted-text role="gh"} and `103193`{.interpreted-text role="gh"}.)

- All `typing.TypedDict`{.interpreted-text role="data"} and `typing.NamedTuple`{.interpreted-text role="data"} classes now have the `__orig_bases__` attribute. (Contributed by Adrian Garcia Badaracco in `103699`{.interpreted-text role="gh"}.)

- Add `frozen_default` parameter to `typing.dataclass_transform`{.interpreted-text role="func"}. (Contributed by Erik De Bonte in `99957`{.interpreted-text role="gh"}.)

### unicodedata

- The Unicode database has been updated to version 15.0.0. (Contributed by Benjamin Peterson in `96734`{.interpreted-text role="gh"}).

### unittest

Add a `--durations` command line option, showing the N slowest test cases:

    python3 -m unittest --durations=3 lib.tests.test_threading
    .....
    Slowest test durations
    ----------------------------------------------------------------------
    1.210s     test_timeout (Lib.test.test_threading.BarrierTests)
    1.003s     test_default_timeout (Lib.test.test_threading.BarrierTests)
    0.518s     test_timeout (Lib.test.test_threading.EventTests)

    (0.000 durations hidden.  Use -v to show these durations.)
    ----------------------------------------------------------------------
    Ran 158 tests in 9.869s

    OK (skipped=3)

(Contributed by Giampaolo Rodola in `48330`{.interpreted-text role="gh"})

### uuid

- Add a `command-line interface <uuid-cli>`{.interpreted-text role="ref"}. (Contributed by Adam Chhina in `88597`{.interpreted-text role="gh"}.)

## Optimizations

- Remove `wstr` and `wstr_length` members from Unicode objects. It reduces object size by 8 or 16 bytes on 64bit platform. (`623`{.interpreted-text role="pep"}) (Contributed by Inada Naoki in `92536`{.interpreted-text role="gh"}.)
- Add experimental support for using the BOLT binary optimizer in the build process, which improves performance by 1-5%. (Contributed by Kevin Modzelewski in `90536`{.interpreted-text role="gh"} and tuned by Donghee Na in `101525`{.interpreted-text role="gh"})
- Speed up the regular expression substitution (functions `re.sub`{.interpreted-text role="func"} and `re.subn`{.interpreted-text role="func"} and corresponding `!re.Pattern`{.interpreted-text role="class"} methods) for replacement strings containing group references by 2\--3 times. (Contributed by Serhiy Storchaka in `91524`{.interpreted-text role="gh"}.)
- Speed up `asyncio.Task`{.interpreted-text role="class"} creation by deferring expensive string formatting. (Contributed by Itamar Oren in `103793`{.interpreted-text role="gh"}.)
- The `tokenize.tokenize`{.interpreted-text role="func"} and `tokenize.generate_tokens`{.interpreted-text role="func"} functions are up to 64% faster as a side effect of the changes required to cover `701`{.interpreted-text role="pep"} in the `tokenize`{.interpreted-text role="mod"} module. (Contributed by Marta Gómez Macías and Pablo Galindo in `102856`{.interpreted-text role="gh"}.)
- Speed up `super`{.interpreted-text role="func"} method calls and attribute loads via the new `LOAD_SUPER_ATTR`{.interpreted-text role="opcode"} instruction. (Contributed by Carl Meyer and Vladimir Matveev in `103497`{.interpreted-text role="gh"}.)

## CPython bytecode changes

- Remove the `!LOAD_METHOD`{.interpreted-text role="opcode"} instruction. It has been merged into `LOAD_ATTR`{.interpreted-text role="opcode"}. `LOAD_ATTR`{.interpreted-text role="opcode"} will now behave like the old `!LOAD_METHOD`{.interpreted-text role="opcode"} instruction if the low bit of its oparg is set. (Contributed by Ken Jin in `93429`{.interpreted-text role="gh"}.)
- Remove the `!JUMP_IF_FALSE_OR_POP`{.interpreted-text role="opcode"} and `!JUMP_IF_TRUE_OR_POP`{.interpreted-text role="opcode"} instructions. (Contributed by Irit Katriel in `102859`{.interpreted-text role="gh"}.)
- Remove the `!PRECALL`{.interpreted-text role="opcode"} instruction. (Contributed by Mark Shannon in `92925`{.interpreted-text role="gh"}.)
- Add the `BINARY_SLICE`{.interpreted-text role="opcode"} and `STORE_SLICE`{.interpreted-text role="opcode"} instructions. (Contributed by Mark Shannon in `94163`{.interpreted-text role="gh"}.)
- Add the `CALL_INTRINSIC_1`{.interpreted-text role="opcode"} instructions. (Contributed by Mark Shannon in `99005`{.interpreted-text role="gh"}.)
- Add the `CALL_INTRINSIC_2`{.interpreted-text role="opcode"} instruction. (Contributed by Irit Katriel in `101799`{.interpreted-text role="gh"}.)
- Add the `CLEANUP_THROW`{.interpreted-text role="opcode"} instruction. (Contributed by Brandt Bucher in `90997`{.interpreted-text role="gh"}.)
- Add the `!END_SEND`{.interpreted-text role="opcode"} instruction. (Contributed by Mark Shannon in `103082`{.interpreted-text role="gh"}.)
- Add the `LOAD_FAST_AND_CLEAR`{.interpreted-text role="opcode"} instruction as part of the implementation of `709`{.interpreted-text role="pep"}. (Contributed by Carl Meyer in `101441`{.interpreted-text role="gh"}.)
- Add the `LOAD_FAST_CHECK`{.interpreted-text role="opcode"} instruction. (Contributed by Dennis Sweeney in `93143`{.interpreted-text role="gh"}.)
- Add the `LOAD_FROM_DICT_OR_DEREF`{.interpreted-text role="opcode"}, `LOAD_FROM_DICT_OR_GLOBALS`{.interpreted-text role="opcode"}, and `LOAD_LOCALS`{.interpreted-text role="opcode"} opcodes as part of the implementation of `695`{.interpreted-text role="pep"}. Remove the `!LOAD_CLASSDEREF`{.interpreted-text role="opcode"} opcode, which can be replaced with `LOAD_LOCALS`{.interpreted-text role="opcode"} plus `LOAD_FROM_DICT_OR_DEREF`{.interpreted-text role="opcode"}. (Contributed by Jelle Zijlstra in `103764`{.interpreted-text role="gh"}.)
- Add the `LOAD_SUPER_ATTR`{.interpreted-text role="opcode"} instruction. (Contributed by Carl Meyer and Vladimir Matveev in `103497`{.interpreted-text role="gh"}.)
- Add the `RETURN_CONST` instruction. (Contributed by Wenyang Wang in `101632`{.interpreted-text role="gh"}.)

## Demos and Tools

- Remove the `Tools/demo/` directory which contained old demo scripts. A copy can be found in the [old-demos project](https://github.com/gvanrossum/old-demos). (Contributed by Victor Stinner in `97681`{.interpreted-text role="gh"}.)
- Remove outdated example scripts of the `Tools/scripts/` directory. A copy can be found in the [old-demos project](https://github.com/gvanrossum/old-demos). (Contributed by Victor Stinner in `97669`{.interpreted-text role="gh"}.)

## Deprecated

- `argparse`{.interpreted-text role="mod"}: The *type*, *choices*, and *metavar* parameters of `!argparse.BooleanOptionalAction`{.interpreted-text role="class"} are deprecated and will be removed in 3.14. (Contributed by Nikita Sobolev in `92248`{.interpreted-text role="gh"}.)

- `ast`{.interpreted-text role="mod"}: The following `ast`{.interpreted-text role="mod"} features have been deprecated in documentation since Python 3.8, now cause a `DeprecationWarning`{.interpreted-text role="exc"} to be emitted at runtime when they are accessed or used, and will be removed in Python 3.14:

  - `!ast.Num`{.interpreted-text role="class"}
  - `!ast.Str`{.interpreted-text role="class"}
  - `!ast.Bytes`{.interpreted-text role="class"}
  - `!ast.NameConstant`{.interpreted-text role="class"}
  - `!ast.Ellipsis`{.interpreted-text role="class"}

  Use `ast.Constant`{.interpreted-text role="class"} instead. (Contributed by Serhiy Storchaka in `90953`{.interpreted-text role="gh"}.)

- `asyncio`{.interpreted-text role="mod"}:

  - The child watcher classes `!asyncio.MultiLoopChildWatcher`{.interpreted-text role="class"}, `!asyncio.FastChildWatcher`{.interpreted-text role="class"}, `!asyncio.AbstractChildWatcher`{.interpreted-text role="class"} and `!asyncio.SafeChildWatcher`{.interpreted-text role="class"} are deprecated and will be removed in Python 3.14. (Contributed by Kumar Aditya in `94597`{.interpreted-text role="gh"}.)
  - `!asyncio.set_child_watcher`{.interpreted-text role="func"}, `!asyncio.get_child_watcher`{.interpreted-text role="func"}, `!asyncio.AbstractEventLoopPolicy.set_child_watcher`{.interpreted-text role="meth"} and `!asyncio.AbstractEventLoopPolicy.get_child_watcher`{.interpreted-text role="meth"} are deprecated and will be removed in Python 3.14. (Contributed by Kumar Aditya in `94597`{.interpreted-text role="gh"}.)
  - The `~asyncio.get_event_loop`{.interpreted-text role="meth"} method of the default event loop policy now emits a `DeprecationWarning`{.interpreted-text role="exc"} if there is no current event loop set and it decides to create one. (Contributed by Serhiy Storchaka and Guido van Rossum in `100160`{.interpreted-text role="gh"}.)

- `calendar`{.interpreted-text role="mod"}: `calendar.January` and `calendar.February` constants are deprecated and replaced by `calendar.JANUARY`{.interpreted-text role="data"} and `calendar.FEBRUARY`{.interpreted-text role="data"}. (Contributed by Prince Roshan in `103636`{.interpreted-text role="gh"}.)

- `collections.abc`{.interpreted-text role="mod"}: Deprecated `collections.abc.ByteString`{.interpreted-text role="class"}.

  Use `isinstance(obj, collections.abc.Buffer)` to test if `obj` implements the `buffer protocol <bufferobjects>`{.interpreted-text role="ref"} at runtime. For use in type annotations, either use `~collections.abc.Buffer`{.interpreted-text role="class"} or a union that explicitly specifies the types your code supports (e.g., `bytes | bytearray | memoryview`).

  `!ByteString`{.interpreted-text role="class"} was originally intended to be an abstract class that would serve as a supertype of both `bytes`{.interpreted-text role="class"} and `bytearray`{.interpreted-text role="class"}. However, since the ABC never had any methods, knowing that an object was an instance of `!ByteString`{.interpreted-text role="class"} never actually told you anything useful about the object. Other common buffer types such as `memoryview`{.interpreted-text role="class"} were also never understood as subtypes of `!ByteString`{.interpreted-text role="class"} (either at runtime or by static type checkers).

  See `PEP 688 <688#current-options>`{.interpreted-text role="pep"} for more details. (Contributed by Shantanu Jain in `91896`{.interpreted-text role="gh"}.)

- `datetime`{.interpreted-text role="mod"}: `datetime.datetime`{.interpreted-text role="class"}\'s `~datetime.datetime.utcnow`{.interpreted-text role="meth"} and `~datetime.datetime.utcfromtimestamp`{.interpreted-text role="meth"} are deprecated and will be removed in a future version. Instead, use timezone-aware objects to represent datetimes in UTC: respectively, call `~datetime.datetime.now`{.interpreted-text role="meth"} and `~datetime.datetime.fromtimestamp`{.interpreted-text role="meth"} with the *tz* parameter set to `datetime.UTC`{.interpreted-text role="const"}. (Contributed by Paul Ganssle in `103857`{.interpreted-text role="gh"}.)

- `email`{.interpreted-text role="mod"}: Deprecate the *isdst* parameter in `email.utils.localtime`{.interpreted-text role="func"}. (Contributed by Alan Williams in `72346`{.interpreted-text role="gh"}.)

- `importlib.abc`{.interpreted-text role="mod"}: Deprecated the following classes, scheduled for removal in Python 3.14:

  - `!importlib.abc.ResourceReader`{.interpreted-text role="class"}
  - `!importlib.abc.Traversable`{.interpreted-text role="class"}
  - `!importlib.abc.TraversableResources`{.interpreted-text role="class"}

  Use `importlib.resources.abc`{.interpreted-text role="mod"} classes instead:

  - `importlib.resources.abc.Traversable`{.interpreted-text role="class"}
  - `importlib.resources.abc.TraversableResources`{.interpreted-text role="class"}

  (Contributed by Jason R. Coombs and Hugo van Kemenade in `93963`{.interpreted-text role="gh"}.)

- `itertools`{.interpreted-text role="mod"}: Deprecate the support for copy, deepcopy, and pickle operations, which is undocumented, inefficient, historically buggy, and inconsistent. This will be removed in 3.14 for a significant reduction in code volume and maintenance burden. (Contributed by Raymond Hettinger in `101588`{.interpreted-text role="gh"}.)

- `multiprocessing`{.interpreted-text role="mod"}: In Python 3.14, the default `multiprocessing`{.interpreted-text role="mod"} start method will change to a safer one on Linux, BSDs, and other non-macOS POSIX platforms where `'fork'` is currently the default (`84559`{.interpreted-text role="gh"}). Adding a runtime warning about this was deemed too disruptive as the majority of code is not expected to care. Use the `~multiprocessing.get_context`{.interpreted-text role="func"} or `~multiprocessing.set_start_method`{.interpreted-text role="func"} APIs to explicitly specify when your code *requires* `'fork'`. See `contexts and start methods
  <multiprocessing-start-methods>`{.interpreted-text role="ref"}.

- `pkgutil`{.interpreted-text role="mod"}: `!pkgutil.find_loader`{.interpreted-text role="func"} and `!pkgutil.get_loader`{.interpreted-text role="func"} are deprecated and will be removed in Python 3.14; use `importlib.util.find_spec`{.interpreted-text role="func"} instead. (Contributed by Nikita Sobolev in `97850`{.interpreted-text role="gh"}.)

- `pty`{.interpreted-text role="mod"}: The module has two undocumented `master_open()` and `slave_open()` functions that have been deprecated since Python 2 but only gained a proper `DeprecationWarning`{.interpreted-text role="exc"} in 3.12. Remove them in 3.14. (Contributed by Soumendra Ganguly and Gregory P. Smith in `85984`{.interpreted-text role="gh"}.)

- `os`{.interpreted-text role="mod"}:

  - The `st_ctime` fields return by `os.stat`{.interpreted-text role="func"} and `os.lstat`{.interpreted-text role="func"} on Windows are deprecated. In a future release, they will contain the last metadata change time, consistent with other platforms. For now, they still contain the creation time, which is also available in the new `st_birthtime` field. (Contributed by Steve Dower in `99726`{.interpreted-text role="gh"}.)
  - On POSIX platforms, `os.fork`{.interpreted-text role="func"} can now raise a `DeprecationWarning`{.interpreted-text role="exc"} when it can detect being called from a multithreaded process. There has always been a fundamental incompatibility with the POSIX platform when doing so. Even if such code *appeared* to work. We added the warning to raise awareness as issues encountered by code doing this are becoming more frequent. See the `os.fork`{.interpreted-text role="func"} documentation for more details along with [this discussion on fork being incompatible with threads](https://discuss.python.org/t/concerns-regarding-deprecation-of-fork-with-alive-threads/33555) for *why* we\'re now surfacing this longstanding platform compatibility problem to developers.

  When this warning appears due to usage of `multiprocessing`{.interpreted-text role="mod"} or `concurrent.futures`{.interpreted-text role="mod"} the fix is to use a different `multiprocessing`{.interpreted-text role="mod"} start method such as `"spawn"` or `"forkserver"`.

- `shutil`{.interpreted-text role="mod"}: The *onerror* argument of `shutil.rmtree`{.interpreted-text role="func"} is deprecated; use *onexc* instead. (Contributed by Irit Katriel in `102828`{.interpreted-text role="gh"}.)

- `sqlite3`{.interpreted-text role="mod"}:

  - `default adapters and converters
    <sqlite3-default-converters>`{.interpreted-text role="ref"} are now deprecated. Instead, use the `sqlite3-adapter-converter-recipes`{.interpreted-text role="ref"} and tailor them to your needs. (Contributed by Erlend E. Aasland in `90016`{.interpreted-text role="gh"}.)
  - In `~sqlite3.Cursor.execute`{.interpreted-text role="meth"}, `DeprecationWarning`{.interpreted-text role="exc"} is now emitted when `named placeholders <sqlite3-placeholders>`{.interpreted-text role="ref"} are used together with parameters supplied as a `sequence`{.interpreted-text role="term"} instead of as a `dict`{.interpreted-text role="class"}. Starting from Python 3.14, using named placeholders with parameters supplied as a sequence will raise a `~sqlite3.ProgrammingError`{.interpreted-text role="exc"}. (Contributed by Erlend E. Aasland in `101698`{.interpreted-text role="gh"}.)

- `sys`{.interpreted-text role="mod"}: The `sys.last_type`{.interpreted-text role="data"}, `sys.last_value`{.interpreted-text role="data"} and `sys.last_traceback`{.interpreted-text role="data"} fields are deprecated. Use `sys.last_exc`{.interpreted-text role="data"} instead. (Contributed by Irit Katriel in `102778`{.interpreted-text role="gh"}.)

- `tarfile`{.interpreted-text role="mod"}: Extracting tar archives without specifying *filter* is deprecated until Python 3.14, when `'data'` filter will become the default. See `tarfile-extraction-filter`{.interpreted-text role="ref"} for details.

- `typing`{.interpreted-text role="mod"}:

  - `typing.Hashable`{.interpreted-text role="class"} and `typing.Sized`{.interpreted-text role="class"}, aliases for `collections.abc.Hashable`{.interpreted-text role="class"} and `collections.abc.Sized`{.interpreted-text role="class"} respectively, are deprecated. (`94309`{.interpreted-text role="gh"}.)
  - `typing.ByteString`{.interpreted-text role="class"}, deprecated since Python 3.9, now causes a `DeprecationWarning`{.interpreted-text role="exc"} to be emitted when it is used. (Contributed by Alex Waygood in `91896`{.interpreted-text role="gh"}.)

- `xml.etree.ElementTree`{.interpreted-text role="mod"}: The module now emits `DeprecationWarning`{.interpreted-text role="exc"} when testing the truth value of an `xml.etree.ElementTree.Element`{.interpreted-text role="class"}. Before, the Python implementation emitted `FutureWarning`{.interpreted-text role="exc"}, and the C implementation emitted nothing. (Contributed by Jacob Walls in `83122`{.interpreted-text role="gh"}.)

- The 3-arg signatures (type, value, traceback) of `coroutine throw()
  <coroutine.throw>`{.interpreted-text role="meth"}, `generator throw() <generator.throw>`{.interpreted-text role="meth"} and `async generator throw() <agen.athrow>`{.interpreted-text role="meth"} are deprecated and may be removed in a future version of Python. Use the single-arg versions of these functions instead. (Contributed by Ofey Chan in `89874`{.interpreted-text role="gh"}.)

- `DeprecationWarning`{.interpreted-text role="exc"} is now raised when `~module.__package__`{.interpreted-text role="attr"} on a module differs from `__spec__.parent <importlib.machinery.ModuleSpec.parent>`{.interpreted-text role="attr"} (previously it was `ImportWarning`{.interpreted-text role="exc"}). (Contributed by Brett Cannon in `65961`{.interpreted-text role="gh"}.)

- Setting `~module.__package__`{.interpreted-text role="attr"} or `__cached__` on a module is deprecated, and will cease to be set or taken into consideration by the import system in Python 3.14. (Contributed by Brett Cannon in `65961`{.interpreted-text role="gh"}.)

- The bitwise inversion operator (`~`) on bool is deprecated. It will throw an error in Python 3.16. Use `not` for logical negation of bools instead. In the rare case that you really need the bitwise inversion of the underlying `int`, convert to int explicitly: `~int(x)`. (Contributed by Tim Hoffmann in `103487`{.interpreted-text role="gh"}.)

- Accessing `~codeobject.co_lnotab`{.interpreted-text role="attr"} on code objects was deprecated in Python 3.10 via `626`{.interpreted-text role="pep"}, but it only got a proper `DeprecationWarning`{.interpreted-text role="exc"} in 3.12. May be removed in 3.15. (Contributed by Nikita Sobolev in `101866`{.interpreted-text role="gh"}.)

### Pending removal in Python 3.13

Modules (see `594`{.interpreted-text role="pep"}):

- `!aifc`{.interpreted-text role="mod"}
- `!audioop`{.interpreted-text role="mod"}
- `!cgi`{.interpreted-text role="mod"}
- `!cgitb`{.interpreted-text role="mod"}
- `!chunk`{.interpreted-text role="mod"}
- `!crypt`{.interpreted-text role="mod"}
- `!imghdr`{.interpreted-text role="mod"}
- `!mailcap`{.interpreted-text role="mod"}
- `!msilib`{.interpreted-text role="mod"}
- `!nis`{.interpreted-text role="mod"}
- `!nntplib`{.interpreted-text role="mod"}
- `!ossaudiodev`{.interpreted-text role="mod"}
- `!pipes`{.interpreted-text role="mod"}
- `!sndhdr`{.interpreted-text role="mod"}
- `!spwd`{.interpreted-text role="mod"}
- `!sunau`{.interpreted-text role="mod"}
- `!telnetlib`{.interpreted-text role="mod"}
- `!uu`{.interpreted-text role="mod"}
- `!xdrlib`{.interpreted-text role="mod"}

Other modules:

- `!lib2to3`{.interpreted-text role="mod"}, and the `2to3`{.interpreted-text role="program"} program (`84540`{.interpreted-text role="gh"})

APIs:

- `!configparser.LegacyInterpolation`{.interpreted-text role="class"} (`90765`{.interpreted-text role="gh"})
- `locale.resetlocale()` (`90817`{.interpreted-text role="gh"})
- `!turtle.RawTurtle.settiltangle`{.interpreted-text role="meth"} (`50096`{.interpreted-text role="gh"})
- `!unittest.findTestCases`{.interpreted-text role="func"} (`50096`{.interpreted-text role="gh"})
- `!unittest.getTestCaseNames`{.interpreted-text role="func"} (`50096`{.interpreted-text role="gh"})
- `!unittest.makeSuite`{.interpreted-text role="func"} (`50096`{.interpreted-text role="gh"})
- `!unittest.TestProgram.usageExit`{.interpreted-text role="meth"} (`67048`{.interpreted-text role="gh"})
- `!webbrowser.MacOSX`{.interpreted-text role="class"} (`86421`{.interpreted-text role="gh"})
- `classmethod`{.interpreted-text role="class"} descriptor chaining (`89519`{.interpreted-text role="gh"})

### Pending removal in Python 3.14

- `argparse`{.interpreted-text role="mod"}: The *type*, *choices*, and *metavar* parameters of `!argparse.BooleanOptionalAction`{.interpreted-text role="class"} are deprecated and will be removed in 3.14. (Contributed by Nikita Sobolev in `92248`{.interpreted-text role="gh"}.)

- `ast`{.interpreted-text role="mod"}: The following features have been deprecated in documentation since Python 3.8, now cause a `DeprecationWarning`{.interpreted-text role="exc"} to be emitted at runtime when they are accessed or used, and will be removed in Python 3.14:

  - `!ast.Num`{.interpreted-text role="class"}
  - `!ast.Str`{.interpreted-text role="class"}
  - `!ast.Bytes`{.interpreted-text role="class"}
  - `!ast.NameConstant`{.interpreted-text role="class"}
  - `!ast.Ellipsis`{.interpreted-text role="class"}

  Use `ast.Constant`{.interpreted-text role="class"} instead. (Contributed by Serhiy Storchaka in `90953`{.interpreted-text role="gh"}.)

- `asyncio`{.interpreted-text role="mod"}:

  - The child watcher classes `!asyncio.MultiLoopChildWatcher`{.interpreted-text role="class"}, `!asyncio.FastChildWatcher`{.interpreted-text role="class"}, `!asyncio.AbstractChildWatcher`{.interpreted-text role="class"} and `!asyncio.SafeChildWatcher`{.interpreted-text role="class"} are deprecated and will be removed in Python 3.14. (Contributed by Kumar Aditya in `94597`{.interpreted-text role="gh"}.)
  - `!asyncio.set_child_watcher`{.interpreted-text role="func"}, `!asyncio.get_child_watcher`{.interpreted-text role="func"}, `!asyncio.AbstractEventLoopPolicy.set_child_watcher`{.interpreted-text role="meth"} and `!asyncio.AbstractEventLoopPolicy.get_child_watcher`{.interpreted-text role="meth"} are deprecated and will be removed in Python 3.14. (Contributed by Kumar Aditya in `94597`{.interpreted-text role="gh"}.)
  - The `~asyncio.get_event_loop`{.interpreted-text role="meth"} method of the default event loop policy now emits a `DeprecationWarning`{.interpreted-text role="exc"} if there is no current event loop set and it decides to create one. (Contributed by Serhiy Storchaka and Guido van Rossum in `100160`{.interpreted-text role="gh"}.)

- `email`{.interpreted-text role="mod"}: Deprecated the *isdst* parameter in `email.utils.localtime`{.interpreted-text role="func"}. (Contributed by Alan Williams in `72346`{.interpreted-text role="gh"}.)

- `importlib.abc`{.interpreted-text role="mod"} deprecated classes:

  - `!importlib.abc.ResourceReader`{.interpreted-text role="class"}
  - `!importlib.abc.Traversable`{.interpreted-text role="class"}
  - `!importlib.abc.TraversableResources`{.interpreted-text role="class"}

  Use `importlib.resources.abc`{.interpreted-text role="mod"} classes instead:

  - `importlib.resources.abc.Traversable`{.interpreted-text role="class"}
  - `importlib.resources.abc.TraversableResources`{.interpreted-text role="class"}

  (Contributed by Jason R. Coombs and Hugo van Kemenade in `93963`{.interpreted-text role="gh"}.)

- `itertools`{.interpreted-text role="mod"} had undocumented, inefficient, historically buggy, and inconsistent support for copy, deepcopy, and pickle operations. This will be removed in 3.14 for a significant reduction in code volume and maintenance burden. (Contributed by Raymond Hettinger in `101588`{.interpreted-text role="gh"}.)

- `multiprocessing`{.interpreted-text role="mod"}: 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 (`84559`{.interpreted-text role="gh"}). Adding a runtime warning about this was deemed too disruptive as the majority of code is not expected to care. Use the `~multiprocessing.get_context`{.interpreted-text role="func"} or `~multiprocessing.set_start_method`{.interpreted-text role="func"} APIs to explicitly specify when your code *requires* `'fork'`. See `multiprocessing-start-methods`{.interpreted-text role="ref"}.

- `pathlib`{.interpreted-text role="mod"}: `~pathlib.PurePath.is_relative_to`{.interpreted-text role="meth"} and `~pathlib.PurePath.relative_to`{.interpreted-text role="meth"}: passing additional arguments is deprecated.

- `pkgutil`{.interpreted-text role="mod"}: `!pkgutil.find_loader`{.interpreted-text role="func"} and `!pkgutil.get_loader`{.interpreted-text role="func"} now raise `DeprecationWarning`{.interpreted-text role="exc"}; use `importlib.util.find_spec`{.interpreted-text role="func"} instead. (Contributed by Nikita Sobolev in `97850`{.interpreted-text role="gh"}.)

- `pty`{.interpreted-text role="mod"}:

  - `master_open()`: use `pty.openpty`{.interpreted-text role="func"}.
  - `slave_open()`: use `pty.openpty`{.interpreted-text role="func"}.

- `sqlite3`{.interpreted-text role="mod"}:

  - `!version`{.interpreted-text role="data"} and `!version_info`{.interpreted-text role="data"}.
  - `~sqlite3.Cursor.execute`{.interpreted-text role="meth"} and `~sqlite3.Cursor.executemany`{.interpreted-text role="meth"} if `named placeholders <sqlite3-placeholders>`{.interpreted-text role="ref"} are used and *parameters* is a sequence instead of a `dict`{.interpreted-text role="class"}.

- `urllib`{.interpreted-text role="mod"}: `!urllib.parse.Quoter`{.interpreted-text role="class"} is deprecated: it was not intended to be a public API. (Contributed by Gregory P. Smith in `88168`{.interpreted-text role="gh"}.)

### Pending removal in Python 3.15

- The import system:
  - Setting `__cached__` on a module while failing to set `__spec__.cached <importlib.machinery.ModuleSpec.cached>`{.interpreted-text role="attr"} is deprecated. In Python 3.15, `__cached__` will cease to be set or take into consideration by the import system or standard library. (`97879`{.interpreted-text role="gh"})
  - Setting `~module.__package__`{.interpreted-text role="attr"} on a module while failing to set `__spec__.parent <importlib.machinery.ModuleSpec.parent>`{.interpreted-text role="attr"} is deprecated. In Python 3.15, `!__package__`{.interpreted-text role="attr"} will cease to be set or take into consideration by the import system or standard library. (`97879`{.interpreted-text role="gh"})
- `ctypes`{.interpreted-text role="mod"}:
  - The undocumented `!ctypes.SetPointerType`{.interpreted-text role="func"} function has been deprecated since Python 3.13.
- `http.server`{.interpreted-text role="mod"}:
  - The obsolete and rarely used `!CGIHTTPRequestHandler`{.interpreted-text role="class"} has been deprecated since Python 3.13. No direct replacement exists. *Anything* is better than CGI to interface a web server with a request handler.
  - The `!--cgi`{.interpreted-text role="option"} flag to the `python -m http.server`{.interpreted-text role="program"} command-line interface has been deprecated since Python 3.13.
- `importlib`{.interpreted-text role="mod"}:
  - `load_module()` method: use `exec_module()` instead.
- `pathlib`{.interpreted-text role="mod"}:
  - `!.PurePath.is_reserved`{.interpreted-text role="meth"} has been deprecated since Python 3.13. Use `os.path.isreserved`{.interpreted-text role="func"} to detect reserved paths on Windows.
- `platform`{.interpreted-text role="mod"}:
  - `!platform.java_ver`{.interpreted-text role="func"} has been deprecated since Python 3.13. This function is only useful for Jython support, has a confusing API, and is largely untested.
- `sysconfig`{.interpreted-text role="mod"}:
  - The *check_home* argument of `sysconfig.is_python_build`{.interpreted-text role="func"} has been deprecated since Python 3.12.
- `threading`{.interpreted-text role="mod"}:
  - `~threading.RLock`{.interpreted-text role="func"} will take no arguments in Python 3.15. Passing any arguments has been deprecated since Python 3.14, as the Python version does not permit any arguments, but the C version allows any number of positional or keyword arguments, ignoring every argument.
- `types`{.interpreted-text role="mod"}:
  - `types.CodeType`{.interpreted-text role="class"}: Accessing `~codeobject.co_lnotab`{.interpreted-text role="attr"} was deprecated in `626`{.interpreted-text role="pep"} since 3.10 and was planned to be removed in 3.12, but it only got a proper `DeprecationWarning`{.interpreted-text role="exc"} in 3.12. May be removed in 3.15. (Contributed by Nikita Sobolev in `101866`{.interpreted-text role="gh"}.)
- `typing`{.interpreted-text role="mod"}:
  - The undocumented keyword argument syntax for creating `~typing.NamedTuple`{.interpreted-text role="class"} classes (for example, `Point = NamedTuple("Point", x=int, y=int)`) has been deprecated since Python 3.13. Use the class-based syntax or the functional syntax instead.
  - When using the functional syntax of `~typing.TypedDict`{.interpreted-text role="class"}s, failing to pass a value to the *fields* parameter (`TD = TypedDict("TD")`) or passing `None` (`TD = TypedDict("TD", None)`) has been deprecated since Python 3.13. Use `class TD(TypedDict): pass` or `TD = TypedDict("TD", {})` to create a TypedDict with zero field.
  - The `!typing.no_type_check_decorator`{.interpreted-text role="func"} decorator function has been deprecated since Python 3.13. After eight years in the `typing`{.interpreted-text role="mod"} module, it has yet to be supported by any major type checker.
- `!sre_compile`{.interpreted-text role="mod"}, `!sre_constants`{.interpreted-text role="mod"} and `!sre_parse`{.interpreted-text role="mod"} modules.
- `wave`{.interpreted-text role="mod"}:
  - The `getmark()`, `setmark()` and `getmarkers()` methods of the `~wave.Wave_read`{.interpreted-text role="class"} and `~wave.Wave_write`{.interpreted-text role="class"} classes have been deprecated since Python 3.13.
- `zipimport`{.interpreted-text role="mod"}:
  - `!zipimport.zipimporter.load_module`{.interpreted-text role="meth"} has been deprecated since Python 3.10. Use `~zipimport.zipimporter.exec_module`{.interpreted-text role="meth"} instead. (`125746`{.interpreted-text role="gh"}.)

### Pending removal in Python 3.16

- The import system:
  - Setting `~module.__loader__`{.interpreted-text role="attr"} on a module while failing to set `__spec__.loader <importlib.machinery.ModuleSpec.loader>`{.interpreted-text role="attr"} is deprecated. In Python 3.16, `!__loader__`{.interpreted-text role="attr"} will cease to be set or taken into consideration by the import system or the standard library.
- `array`{.interpreted-text role="mod"}:
  - The `'u'` format code (`wchar_t`{.interpreted-text role="c:type"}) has been deprecated in documentation since Python 3.3 and at runtime since Python 3.13. Use the `'w'` format code (`Py_UCS4`{.interpreted-text role="c:type"}) for Unicode characters instead.
- `asyncio`{.interpreted-text role="mod"}:
  - `!asyncio.iscoroutinefunction`{.interpreted-text role="func"} is deprecated and will be removed in Python 3.16; use `inspect.iscoroutinefunction`{.interpreted-text role="func"} instead. (Contributed by Jiahao Li and Kumar Aditya in `122875`{.interpreted-text role="gh"}.)

  - `asyncio`{.interpreted-text role="mod"} policy system is deprecated and will be removed in Python 3.16. In particular, the following classes and functions are deprecated:

    - `asyncio.AbstractEventLoopPolicy`{.interpreted-text role="class"}
    - `asyncio.DefaultEventLoopPolicy`{.interpreted-text role="class"}
    - `asyncio.WindowsSelectorEventLoopPolicy`{.interpreted-text role="class"}
    - `asyncio.WindowsProactorEventLoopPolicy`{.interpreted-text role="class"}
    - `asyncio.get_event_loop_policy`{.interpreted-text role="func"}
    - `asyncio.set_event_loop_policy`{.interpreted-text role="func"}

    Users should use `asyncio.run`{.interpreted-text role="func"} or `asyncio.Runner`{.interpreted-text role="class"} with *loop_factory* to use the desired event loop implementation.

    For example, to use `asyncio.SelectorEventLoop`{.interpreted-text role="class"} on Windows:

        import asyncio

        async def main():
            ...

        asyncio.run(main(), loop_factory=asyncio.SelectorEventLoop)

    (Contributed by Kumar Aditya in `127949`{.interpreted-text role="gh"}.)
- `builtins`{.interpreted-text role="mod"}:
  - Bitwise inversion on boolean types, `~True` or `~False` has been deprecated since Python 3.12, as it produces surprising and unintuitive results (`-2` and `-1`). Use `not x` instead for the logical negation of a Boolean. In the rare case that you need the bitwise inversion of the underlying integer, convert to `int` explicitly (`~int(x)`).
- `functools`{.interpreted-text role="mod"}:
  - Calling the Python implementation of `functools.reduce`{.interpreted-text role="func"} with *function* or *sequence* as keyword arguments has been deprecated since Python 3.14.
- `logging`{.interpreted-text role="mod"}:
  - Support for custom logging handlers with the *strm* argument is deprecated and scheduled for removal in Python 3.16. Define handlers with the *stream* argument instead. (Contributed by Mariusz Felisiak in `115032`{.interpreted-text role="gh"}.)
- `mimetypes`{.interpreted-text role="mod"}:
  - Valid extensions start with a \'.\' or are empty for `mimetypes.MimeTypes.add_type`{.interpreted-text role="meth"}. Undotted extensions are deprecated and will raise a `ValueError`{.interpreted-text role="exc"} in Python 3.16. (Contributed by Hugo van Kemenade in `75223`{.interpreted-text role="gh"}.)
- `shutil`{.interpreted-text role="mod"}:
  - The `!ExecError`{.interpreted-text role="class"} exception has been deprecated since Python 3.14. It has not been used by any function in `!shutil`{.interpreted-text role="mod"} since Python 3.4, and is now an alias of `RuntimeError`{.interpreted-text role="exc"}.
- `symtable`{.interpreted-text role="mod"}:
  - The `Class.get_methods <symtable.Class.get_methods>`{.interpreted-text role="meth"} method has been deprecated since Python 3.14.
- `sys`{.interpreted-text role="mod"}:
  - The `~sys._enablelegacywindowsfsencoding`{.interpreted-text role="func"} function has been deprecated since Python 3.13. Use the `PYTHONLEGACYWINDOWSFSENCODING`{.interpreted-text role="envvar"} environment variable instead.
- `sysconfig`{.interpreted-text role="mod"}:
  - The `!sysconfig.expand_makefile_vars`{.interpreted-text role="func"} function has been deprecated since Python 3.14. Use the `vars` argument of `sysconfig.get_paths`{.interpreted-text role="func"} instead.
- `tarfile`{.interpreted-text role="mod"}:
  - The undocumented and unused `!TarFile.tarfile`{.interpreted-text role="attr"} attribute has been deprecated since Python 3.13.

### Pending removal in Python 3.17

- `collections.abc`{.interpreted-text role="mod"}:
  - `collections.abc.ByteString`{.interpreted-text role="class"} is scheduled for removal in Python 3.17.

    Use `isinstance(obj, collections.abc.Buffer)` to test if `obj` implements the `buffer protocol <bufferobjects>`{.interpreted-text role="ref"} at runtime. For use in type annotations, either use `~collections.abc.Buffer`{.interpreted-text role="class"} or a union that explicitly specifies the types your code supports (e.g., `bytes | bytearray | memoryview`).

    `!ByteString`{.interpreted-text role="class"} was originally intended to be an abstract class that would serve as a supertype of both `bytes`{.interpreted-text role="class"} and `bytearray`{.interpreted-text role="class"}. However, since the ABC never had any methods, knowing that an object was an instance of `!ByteString`{.interpreted-text role="class"} never actually told you anything useful about the object. Other common buffer types such as `memoryview`{.interpreted-text role="class"} were also never understood as subtypes of `!ByteString`{.interpreted-text role="class"} (either at runtime or by static type checkers).

    See `PEP 688 <688#current-options>`{.interpreted-text role="pep"} for more details. (Contributed by Shantanu Jain in `91896`{.interpreted-text role="gh"}.)
- `encodings`{.interpreted-text role="mod"}:
  - Passing non-ascii *encoding* names to `encodings.normalize_encoding`{.interpreted-text role="func"} is deprecated and scheduled for removal in Python 3.17. (Contributed by Stan Ulbrych in `136702`{.interpreted-text role="gh"})
- `typing`{.interpreted-text role="mod"}:
  - Before Python 3.14, old-style unions were implemented using the private class `typing._UnionGenericAlias`. This class is no longer needed for the implementation, but it has been retained for backward compatibility, with removal scheduled for Python 3.17. Users should use documented introspection helpers like `typing.get_origin`{.interpreted-text role="func"} and `typing.get_args`{.interpreted-text role="func"} instead of relying on private implementation details.

  - `typing.ByteString`{.interpreted-text role="class"}, deprecated since Python 3.9, is scheduled for removal in Python 3.17.

    Use `isinstance(obj, collections.abc.Buffer)` to test if `obj` implements the `buffer protocol <bufferobjects>`{.interpreted-text role="ref"} at runtime. For use in type annotations, either use `~collections.abc.Buffer`{.interpreted-text role="class"} or a union that explicitly specifies the types your code supports (e.g., `bytes | bytearray | memoryview`).

    `!ByteString`{.interpreted-text role="class"} was originally intended to be an abstract class that would serve as a supertype of both `bytes`{.interpreted-text role="class"} and `bytearray`{.interpreted-text role="class"}. However, since the ABC never had any methods, knowing that an object was an instance of `!ByteString`{.interpreted-text role="class"} never actually told you anything useful about the object. Other common buffer types such as `memoryview`{.interpreted-text role="class"} were also never understood as subtypes of `!ByteString`{.interpreted-text role="class"} (either at runtime or by static type checkers).

    See `PEP 688 <688#current-options>`{.interpreted-text role="pep"} for more details. (Contributed by Shantanu Jain in `91896`{.interpreted-text role="gh"}.)

### Pending removal in Python 3.19

- `ctypes`{.interpreted-text role="mod"}:
  - Implicitly switching to the MSVC-compatible struct layout by setting `~ctypes.Structure._pack_`{.interpreted-text role="attr"} but not `~ctypes.Structure._layout_`{.interpreted-text role="attr"} on non-Windows platforms.
- `hashlib`{.interpreted-text role="mod"}:
  - In hash function constructors such as `~hashlib.new`{.interpreted-text role="func"} or the direct hash-named constructors such as `~hashlib.md5`{.interpreted-text role="func"} and `~hashlib.sha256`{.interpreted-text role="func"}, their optional initial data parameter could also be passed a keyword argument named `data=` or `string=` in various `!hashlib`{.interpreted-text role="mod"} implementations.

    Support for the `string` keyword argument name is now deprecated and slated for removal in Python 3.19.

    Before Python 3.13, the `string` keyword parameter was not correctly supported depending on the backend implementation of hash functions. Prefer passing the initial data as a positional argument for maximum backwards compatibility.

### Pending removal in Python 3.20

- The `__version__`, `version` and `VERSION` attributes have been deprecated in these standard library modules and will be removed in Python 3.20. Use `sys.version_info`{.interpreted-text role="py:data"} instead.

  - `argparse`{.interpreted-text role="mod"}
  - `csv`{.interpreted-text role="mod"}
  - `ctypes`{.interpreted-text role="mod"}
  - `!ctypes.macholib`{.interpreted-text role="mod"}
  - `decimal`{.interpreted-text role="mod"} (use `decimal.SPEC_VERSION`{.interpreted-text role="data"} instead)
  - `http.server`{.interpreted-text role="mod"}
  - `imaplib`{.interpreted-text role="mod"}
  - `ipaddress`{.interpreted-text role="mod"}
  - `json`{.interpreted-text role="mod"}
  - `logging`{.interpreted-text role="mod"} (`__date__` also deprecated)
  - `optparse`{.interpreted-text role="mod"}
  - `pickle`{.interpreted-text role="mod"}
  - `platform`{.interpreted-text role="mod"}
  - `re`{.interpreted-text role="mod"}
  - `socketserver`{.interpreted-text role="mod"}
  - `tabnanny`{.interpreted-text role="mod"}
  - `tkinter.font`{.interpreted-text role="mod"}
  - `tkinter.ttk`{.interpreted-text role="mod"}
  - `wsgiref.simple_server`{.interpreted-text role="mod"}
  - `xml.etree.ElementTree`{.interpreted-text role="mod"}
  - `!xml.sax.expatreader`{.interpreted-text role="mod"}
  - `xml.sax.handler`{.interpreted-text role="mod"}
  - `zlib`{.interpreted-text role="mod"}

  (Contributed by Hugo van Kemenade and Stan Ulbrych in `76007`{.interpreted-text role="gh"}.)

### Pending removal in future versions

The following APIs will be removed in the future, although there is currently no date scheduled for their removal.

- `argparse`{.interpreted-text role="mod"}:
  - Nesting argument groups and nesting mutually exclusive groups are deprecated.
  - Passing the undocumented keyword argument *prefix_chars* to `~argparse.ArgumentParser.add_argument_group`{.interpreted-text role="meth"} is now deprecated.
  - The `argparse.FileType`{.interpreted-text role="class"} type converter is deprecated.
- `builtins`{.interpreted-text role="mod"}:
  - 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`{.interpreted-text role="keyword"}, `else`{.interpreted-text role="keyword"}, `for`{.interpreted-text role="keyword"}, `if`{.interpreted-text role="keyword"}, `in`{.interpreted-text role="keyword"}, `is`{.interpreted-text role="keyword"} and `or`{.interpreted-text role="keyword"}. In a future release it will be changed to a syntax error. (`87999`{.interpreted-text role="gh"})
  - 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`{.interpreted-text role="class"}.
  - Support for `__float__()` method returning a strict subclass of `float`{.interpreted-text role="class"}: these methods will be required to return an instance of `float`{.interpreted-text role="class"}.
  - Support for `__complex__()` method returning a strict subclass of `complex`{.interpreted-text role="class"}: these methods will be required to return an instance of `complex`{.interpreted-text role="class"}.
  - Passing a complex number as the *real* or *imag* argument in the `complex`{.interpreted-text role="func"} constructor is now deprecated; it should only be passed as a single positional argument. (Contributed by Serhiy Storchaka in `109218`{.interpreted-text role="gh"}.)
- `calendar`{.interpreted-text role="mod"}: `calendar.January` and `calendar.February` constants are deprecated and replaced by `calendar.JANUARY`{.interpreted-text role="data"} and `calendar.FEBRUARY`{.interpreted-text role="data"}. (Contributed by Prince Roshan in `103636`{.interpreted-text role="gh"}.)
- `codecs`{.interpreted-text role="mod"}: use `open`{.interpreted-text role="func"} instead of `codecs.open`{.interpreted-text role="func"}. (`133038`{.interpreted-text role="gh"})
- `codeobject.co_lnotab`{.interpreted-text role="attr"}: use the `codeobject.co_lines`{.interpreted-text role="meth"} method instead.
- `datetime`{.interpreted-text role="mod"}:
  - `~datetime.datetime.utcnow`{.interpreted-text role="meth"}: use `datetime.datetime.now(tz=datetime.UTC)`.
  - `~datetime.datetime.utcfromtimestamp`{.interpreted-text role="meth"}: use `datetime.datetime.fromtimestamp(timestamp, tz=datetime.UTC)`.
- `gettext`{.interpreted-text role="mod"}: Plural value must be an integer.
- `importlib`{.interpreted-text role="mod"}:
  - `~importlib.util.cache_from_source`{.interpreted-text role="func"} *debug_override* parameter is deprecated: use the *optimization* parameter instead.
- `importlib.metadata`{.interpreted-text role="mod"}:
  - `EntryPoints` tuple interface.
  - Implicit `None` on return values.
- `logging`{.interpreted-text role="mod"}: the `warn()` method has been deprecated since Python 3.3, use `~logging.warning`{.interpreted-text role="meth"} instead.
- `mailbox`{.interpreted-text role="mod"}: Use of StringIO input and text mode is deprecated, use BytesIO and binary mode instead.
- `os`{.interpreted-text role="mod"}: Calling `os.register_at_fork`{.interpreted-text role="func"} in a multi-threaded process.
- `os.path`{.interpreted-text role="mod"}: `os.path.commonprefix`{.interpreted-text role="func"} is deprecated, use `os.path.commonpath`{.interpreted-text role="func"} for path prefixes. The `os.path.commonprefix`{.interpreted-text role="func"} function is being deprecated due to having a misleading name and module. The function is not safe to use for path prefixes despite being included in a module about path manipulation, meaning it is easy to accidentally introduce path traversal vulnerabilities into Python programs by using this function.
- `!pydoc.ErrorDuringImport`{.interpreted-text role="class"}: A tuple value for *exc_info* parameter is deprecated, use an exception instance.
- `re`{.interpreted-text role="mod"}: 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 `91760`{.interpreted-text role="gh"}.)
- `shutil`{.interpreted-text role="mod"}: `~shutil.rmtree`{.interpreted-text role="func"}\'s *onerror* parameter is deprecated in Python 3.12; use the *onexc* parameter instead.
- `ssl`{.interpreted-text role="mod"} options and protocols:
  - `ssl.SSLContext`{.interpreted-text role="class"} without protocol argument is deprecated.
  - `ssl.SSLContext`{.interpreted-text role="class"}: `~ssl.SSLContext.set_npn_protocols`{.interpreted-text role="meth"} and `!selected_npn_protocol`{.interpreted-text role="meth"} are deprecated: use ALPN instead.
  - `ssl.OP_NO_SSL*` options
  - `ssl.OP_NO_TLS*` options
  - `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`{.interpreted-text role="mod"} methods:
  - `!threading.Condition.notifyAll`{.interpreted-text role="meth"}: use `~threading.Condition.notify_all`{.interpreted-text role="meth"}.
  - `!threading.Event.isSet`{.interpreted-text role="meth"}: use `~threading.Event.is_set`{.interpreted-text role="meth"}.
  - `!threading.Thread.isDaemon`{.interpreted-text role="meth"}, `threading.Thread.setDaemon`{.interpreted-text role="meth"}: use `threading.Thread.daemon`{.interpreted-text role="attr"} attribute.
  - `!threading.Thread.getName`{.interpreted-text role="meth"}, `threading.Thread.setName`{.interpreted-text role="meth"}: use `threading.Thread.name`{.interpreted-text role="attr"} attribute.
  - `!threading.currentThread`{.interpreted-text role="meth"}: use `threading.current_thread`{.interpreted-text role="meth"}.
  - `!threading.activeCount`{.interpreted-text role="meth"}: use `threading.active_count`{.interpreted-text role="meth"}.
- `typing.Text`{.interpreted-text role="class"} (`92332`{.interpreted-text role="gh"}).
- The internal class `typing._UnionGenericAlias` is no longer used to implement `typing.Union`{.interpreted-text role="class"}. To preserve compatibility with users using this private class, a compatibility shim will be provided until at least Python 3.17. (Contributed by Jelle Zijlstra in `105499`{.interpreted-text role="gh"}.)
- `unittest.IsolatedAsyncioTestCase`{.interpreted-text role="class"}: it is deprecated to return a value that is not `None` from a test case.
- `urllib.parse`{.interpreted-text role="mod"} deprecated functions: `~urllib.parse.urlparse`{.interpreted-text role="func"} instead
  - `splitattr()`
  - `splithost()`
  - `splitnport()`
  - `splitpasswd()`
  - `splitport()`
  - `splitquery()`
  - `splittag()`
  - `splittype()`
  - `splituser()`
  - `splitvalue()`
  - `to_bytes()`
- `wsgiref`{.interpreted-text role="mod"}: `SimpleHandler.stdout.write()` should not do partial writes.
- `xml.etree.ElementTree`{.interpreted-text role="mod"}: Testing the truth value of an `~xml.etree.ElementTree.Element`{.interpreted-text role="class"} is deprecated. In a future release it will always return `True`. Prefer explicit `len(elem)` or `elem is not None` tests instead.
- `sys._clear_type_cache`{.interpreted-text role="func"} is deprecated: use `sys._clear_internal_caches`{.interpreted-text role="func"} instead.

## Removed {#whatsnew312-removed}

### asynchat and asyncore

- These two modules have been removed according to the schedule in `594`{.interpreted-text role="pep"}, having been deprecated in Python 3.6. Use `asyncio`{.interpreted-text role="mod"} instead. (Contributed by Nikita Sobolev in `96580`{.interpreted-text role="gh"}.)

### configparser

- Several names deprecated in the `configparser`{.interpreted-text role="mod"} way back in 3.2 have been removed per `89336`{.interpreted-text role="gh"}:
  - `configparser.ParsingError`{.interpreted-text role="class"} no longer has a `filename` attribute or argument. Use the `source` attribute and argument instead.
  - `configparser`{.interpreted-text role="mod"} no longer has a `SafeConfigParser` class. Use the shorter `~configparser.ConfigParser`{.interpreted-text role="class"} name instead.
  - `configparser.ConfigParser`{.interpreted-text role="class"} no longer has a `readfp` method. Use `~configparser.ConfigParser.read_file`{.interpreted-text role="meth"} instead.

### distutils {#whatsnew312-removed-distutils}

- Remove the `!distutils`{.interpreted-text role="py:mod"} package. It was deprecated in Python 3.10 by `632`{.interpreted-text role="pep"} \"Deprecate distutils module\". For projects still using `distutils` and cannot be updated to something else, the `setuptools` project can be installed: it still provides `distutils`. (Contributed by Victor Stinner in `92584`{.interpreted-text role="gh"}.)

### ensurepip

- Remove the bundled setuptools wheel from `ensurepip`{.interpreted-text role="mod"}, and stop installing setuptools in environments created by `venv`{.interpreted-text role="mod"}.

  `pip (>= 22.1)` does not require setuptools to be installed in the environment. `setuptools`-based (and `distutils`-based) packages can still be used with `pip install`, since pip will provide `setuptools` in the build environment it uses for building a package.

  `easy_install`, `pkg_resources`, `setuptools` and `distutils` are no longer provided by default in environments created with `venv` or bootstrapped with `ensurepip`, since they are part of the `setuptools` package. For projects relying on these at runtime, the `setuptools` project should be declared as a dependency and installed separately (typically, using pip).

  (Contributed by Pradyun Gedam in `95299`{.interpreted-text role="gh"}.)

### enum

- Remove `enum`{.interpreted-text role="mod"}\'s `EnumMeta.__getattr__`, which is no longer needed for enum attribute access. (Contributed by Ethan Furman in `95083`{.interpreted-text role="gh"}.)

### ftplib

- Remove `ftplib`{.interpreted-text role="mod"}\'s `FTP_TLS.ssl_version` class attribute: use the *context* parameter instead. (Contributed by Victor Stinner in `94172`{.interpreted-text role="gh"}.)

### gzip

- Remove the `filename` attribute of `gzip`{.interpreted-text role="mod"}\'s `gzip.GzipFile`{.interpreted-text role="class"}, deprecated since Python 2.6, use the `~gzip.GzipFile.name`{.interpreted-text role="attr"} attribute instead. In write mode, the `filename` attribute added `'.gz'` file extension if it was not present. (Contributed by Victor Stinner in `94196`{.interpreted-text role="gh"}.)

### hashlib

- Remove the pure Python implementation of `hashlib`{.interpreted-text role="mod"}\'s `hashlib.pbkdf2_hmac`{.interpreted-text role="func"}, deprecated in Python 3.10. Python 3.10 and newer requires OpenSSL 1.1.1 (`644`{.interpreted-text role="pep"}): this OpenSSL version provides a C implementation of `~hashlib.pbkdf2_hmac`{.interpreted-text role="func"} which is faster. (Contributed by Victor Stinner in `94199`{.interpreted-text role="gh"}.)

### importlib

- Many previously deprecated cleanups in `importlib`{.interpreted-text role="mod"} have now been completed:
  - References to, and support for `!module_repr`{.interpreted-text role="meth"} has been removed. (Contributed by Barry Warsaw in `97850`{.interpreted-text role="gh"}.)
  - `importlib.util.set_package`, `importlib.util.set_loader` and `importlib.util.module_for_loader` have all been removed. (Contributed by Brett Cannon and Nikita Sobolev in `65961`{.interpreted-text role="gh"} and `97850`{.interpreted-text role="gh"}.)
  - Support for `find_loader()` and `find_module()` APIs have been removed. (Contributed by Barry Warsaw in `98040`{.interpreted-text role="gh"}.)
  - `importlib.abc.Finder`, `pkgutil.ImpImporter`, and `pkgutil.ImpLoader` have been removed. (Contributed by Barry Warsaw in `98040`{.interpreted-text role="gh"}.)

### imp {#whatsnew312-removed-imp}

- The `!imp`{.interpreted-text role="mod"} module has been removed. (Contributed by Barry Warsaw in `98040`{.interpreted-text role="gh"}.)

  To migrate, consult the following correspondence table:

  > 
  >   imp                         importlib
  >   --------------------------- ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  >   `imp.NullImporter`          Insert `None` into `sys.path_importer_cache`
  >   `imp.cache_from_source()`   `importlib.util.cache_from_source`{.interpreted-text role="func"}
  >   `imp.find_module()`         `importlib.util.find_spec`{.interpreted-text role="func"}
  >   `imp.get_magic()`           `importlib.util.MAGIC_NUMBER`{.interpreted-text role="const"}
  >   `imp.get_suffixes()`        `importlib.machinery.SOURCE_SUFFIXES`{.interpreted-text role="const"}, `importlib.machinery.EXTENSION_SUFFIXES`{.interpreted-text role="const"}, and `importlib.machinery.BYTECODE_SUFFIXES`{.interpreted-text role="const"}
  >   `imp.get_tag()`             `sys.implementation.cache_tag <sys.implementation>`{.interpreted-text role="attr"}
  >   `imp.load_module()`         `importlib.import_module`{.interpreted-text role="func"}
  >   `imp.new_module(name)`      `types.ModuleType(name)`
  >   `imp.reload()`              `importlib.reload`{.interpreted-text role="func"}
  >   `imp.source_from_cache()`   `importlib.util.source_from_cache`{.interpreted-text role="func"}
  >   `imp.load_source()`         *See below*

  Replace `imp.load_source()` with:

      import importlib.util
      import importlib.machinery

      def load_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)
          # The module is always executed and not cached in sys.modules.
          # Uncomment the following line to cache the module.
          # sys.modules[module.__name__] = module
          loader.exec_module(module)
          return module

- Remove `!imp`{.interpreted-text role="mod"} functions and attributes with no replacements:

  - Undocumented functions:
    - `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()` constants: `SEARCH_ERROR`, `PY_SOURCE`, `PY_COMPILED`, `C_EXTENSION`, `PY_RESOURCE`, `PKG_DIRECTORY`, `C_BUILTIN`, `PY_FROZEN`, `PY_CODERESOURCE`, `IMP_HOOK`.

### io

- Remove `io`{.interpreted-text role="mod"}\'s `io.OpenWrapper` and `_pyio.OpenWrapper`, deprecated in Python 3.10: just use `open`{.interpreted-text role="func"} instead. The `open`{.interpreted-text role="func"} (`io.open`{.interpreted-text role="func"}) function is a built-in function. Since Python 3.10, `!_pyio.open`{.interpreted-text role="func"} is also a static method. (Contributed by Victor Stinner in `94169`{.interpreted-text role="gh"}.)

### locale

- Remove `locale`{.interpreted-text role="mod"}\'s `!locale.format`{.interpreted-text role="func"} function, deprecated in Python 3.7: use `locale.format_string`{.interpreted-text role="func"} instead. (Contributed by Victor Stinner in `94226`{.interpreted-text role="gh"}.)

### smtpd

- The `smtpd` module has been removed according to the schedule in `594`{.interpreted-text role="pep"}, having been deprecated in Python 3.4.7 and 3.5.4. Use the `aiosmtpd`{.interpreted-text role="pypi"} PyPI module or any other `asyncio`{.interpreted-text role="mod"}-based server instead. (Contributed by Oleg Iarygin in `93243`{.interpreted-text role="gh"}.)

### sqlite3

- The following undocumented `sqlite3`{.interpreted-text role="mod"} features, deprecated in Python 3.10, are now removed:

  - `sqlite3.enable_shared_cache()`
  - `sqlite3.OptimizedUnicode`

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

  The `sqlite3.OptimizedUnicode` text factory has been an alias for `str`{.interpreted-text role="class"} since Python 3.3. Code that previously set the text factory to `OptimizedUnicode` can either use `str` explicitly, or rely on the default value which is also `str`.

  (Contributed by Erlend E. Aasland in `92548`{.interpreted-text role="gh"}.)

### ssl

- Remove `ssl`{.interpreted-text role="mod"}\'s `!ssl.RAND_pseudo_bytes`{.interpreted-text role="func"} function, deprecated in Python 3.6: use `os.urandom`{.interpreted-text role="func"} or `ssl.RAND_bytes`{.interpreted-text role="func"} instead. (Contributed by Victor Stinner in `94199`{.interpreted-text role="gh"}.)
- Remove the `!ssl.match_hostname`{.interpreted-text role="func"} function. It was deprecated in Python 3.7. OpenSSL performs hostname matching since Python 3.7, Python no longer uses the `!ssl.match_hostname`{.interpreted-text role="func"} function. (Contributed by Victor Stinner in `94199`{.interpreted-text role="gh"}.)
- Remove the `!ssl.wrap_socket`{.interpreted-text role="func"} function, deprecated in Python 3.7: instead, create a `ssl.SSLContext`{.interpreted-text role="class"} object and call its `ssl.SSLContext.wrap_socket`{.interpreted-text role="class"} method. Any package that still uses `!ssl.wrap_socket`{.interpreted-text role="func"} is broken and insecure. The function neither sends a SNI TLS extension nor validates the server hostname. Code is subject to `295`{.interpreted-text role="cwe"} (Improper Certificate Validation). (Contributed by Victor Stinner in `94199`{.interpreted-text role="gh"}.)

### unittest

- Remove many long-deprecated `unittest`{.interpreted-text role="mod"} features:

  ::: {#unittest-TestCase-removed-aliases}
  - A number of `~unittest.TestCase`{.interpreted-text role="class"} method aliases:

      Deprecated alias           Method Name                                              Deprecated in
      -------------------------- -------------------------------------------------------- ---------------
      `failUnless`               `.assertTrue`{.interpreted-text role="meth"}             3.1
      `failIf`                   `.assertFalse`{.interpreted-text role="meth"}            3.1
      `failUnlessEqual`          `.assertEqual`{.interpreted-text role="meth"}            3.1
      `failIfEqual`              `.assertNotEqual`{.interpreted-text role="meth"}         3.1
      `failUnlessAlmostEqual`    `.assertAlmostEqual`{.interpreted-text role="meth"}      3.1
      `failIfAlmostEqual`        `.assertNotAlmostEqual`{.interpreted-text role="meth"}   3.1
      `failUnlessRaises`         `.assertRaises`{.interpreted-text role="meth"}           3.1
      `assert_`                  `.assertTrue`{.interpreted-text role="meth"}             3.2
      `assertEquals`             `.assertEqual`{.interpreted-text role="meth"}            3.2
      `assertNotEquals`          `.assertNotEqual`{.interpreted-text role="meth"}         3.2
      `assertAlmostEquals`       `.assertAlmostEqual`{.interpreted-text role="meth"}      3.2
      `assertNotAlmostEquals`    `.assertNotAlmostEqual`{.interpreted-text role="meth"}   3.2
      `assertRegexpMatches`      `.assertRegex`{.interpreted-text role="meth"}            3.2
      `assertRaisesRegexp`       `.assertRaisesRegex`{.interpreted-text role="meth"}      3.2
      `assertNotRegexpMatches`   `.assertNotRegex`{.interpreted-text role="meth"}         3.5

    You can use <https://github.com/isidentical/teyit> to automatically modernise your unit tests.

  - Undocumented and broken `~unittest.TestCase`{.interpreted-text role="class"} method `assertDictContainsSubset` (deprecated in Python 3.2).

  - Undocumented `TestLoader.loadTestsFromModule
    <unittest.TestLoader.loadTestsFromModule>`{.interpreted-text role="meth"} parameter *use_load_tests* (deprecated and ignored since Python 3.5).

  - An alias of the `~unittest.TextTestResult`{.interpreted-text role="class"} class: `_TextTestResult` (deprecated in Python 3.2).
  :::

  (Contributed by Serhiy Storchaka in `89325`{.interpreted-text role="gh"}.)

### webbrowser

- Remove support for obsolete browsers from `webbrowser`{.interpreted-text role="mod"}. The removed browsers include: Grail, Mosaic, Netscape, Galeon, Skipstone, Iceape, Firebird, and Firefox versions 35 and below (`102871`{.interpreted-text role="gh"}).

### xml.etree.ElementTree

- Remove the `ElementTree.Element.copy()` method of the pure Python implementation, deprecated in Python 3.10, use the `copy.copy`{.interpreted-text role="func"} function instead. The C implementation of `xml.etree.ElementTree`{.interpreted-text role="mod"} has no `copy()` method, only a `__copy__()` method. (Contributed by Victor Stinner in `94383`{.interpreted-text role="gh"}.)

### zipimport

- Remove `zipimport`{.interpreted-text role="mod"}\'s `find_loader()` and `find_module()` methods, deprecated in Python 3.10: use the `find_spec()` method instead. See `451`{.interpreted-text role="pep"} for the rationale. (Contributed by Victor Stinner in `94379`{.interpreted-text role="gh"}.)

### Others

- Remove the `suspicious` rule from the documentation `Makefile`{.interpreted-text role="file"} and `Doc/tools/rstlint.py`{.interpreted-text role="file"}, both in favor of [sphinx-lint](https://github.com/sphinx-contrib/sphinx-lint). (Contributed by Julien Palard in `98179`{.interpreted-text role="gh"}.)
- Remove the *keyfile* and *certfile* parameters from the `ftplib`{.interpreted-text role="mod"}, `imaplib`{.interpreted-text role="mod"}, `poplib`{.interpreted-text role="mod"} and `smtplib`{.interpreted-text role="mod"} modules, and the *key_file*, *cert_file* and *check_hostname* parameters from the `http.client`{.interpreted-text role="mod"} module, all deprecated since Python 3.6. Use the *context* parameter (*ssl_context* in `imaplib`{.interpreted-text role="mod"}) instead. (Contributed by Victor Stinner in `94172`{.interpreted-text role="gh"}.)
- Remove `Jython` compatibility hacks from several stdlib modules and tests. (Contributed by Nikita Sobolev in `99482`{.interpreted-text role="gh"}.)
- Remove `_use_broken_old_ctypes_structure_semantics_` flag from `ctypes`{.interpreted-text role="mod"} module. (Contributed by Nikita Sobolev in `99285`{.interpreted-text role="gh"}.)

## Porting to Python 3.12 {#whatsnew312-porting-to-python312}

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

### Changes in the Python API

- 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 `91760`{.interpreted-text role="gh"}.)

- Remove `randrange()` functionality deprecated since Python 3.10. Formerly, `randrange(10.0)` losslessly converted to `randrange(10)`. Now, it raises a `TypeError`{.interpreted-text role="exc"}. Also, the exception raised for non-integer values such as `randrange(10.5)` or `randrange('10')` has been changed from `ValueError`{.interpreted-text role="exc"} to `TypeError`{.interpreted-text role="exc"}. This also prevents bugs where `randrange(1e25)` would silently select from a larger range than `randrange(10**25)`. (Originally suggested by Serhiy Storchaka `86388`{.interpreted-text role="gh"}.)

- `argparse.ArgumentParser`{.interpreted-text role="class"} changed encoding and error handler for reading arguments from file (e.g. `fromfile_prefix_chars` option) from default text encoding (e.g. `locale.getpreferredencoding(False) <locale.getpreferredencoding>`{.interpreted-text role="func"}) to `filesystem encoding and error handler`{.interpreted-text role="term"}. Argument files should be encoded in UTF-8 instead of ANSI Codepage on Windows.

- Remove the `asyncore`-based `smtpd` module deprecated in Python 3.4.7 and 3.5.4. A recommended replacement is the `asyncio`{.interpreted-text role="mod"}-based `aiosmtpd`{.interpreted-text role="pypi"} PyPI module.

- `shlex.split`{.interpreted-text role="func"}: Passing `None` for *s* argument now raises an exception, rather than reading `sys.stdin`{.interpreted-text role="data"}. The feature was deprecated in Python 3.9. (Contributed by Victor Stinner in `94352`{.interpreted-text role="gh"}.)

- The `os`{.interpreted-text role="mod"} module no longer accepts bytes-like paths, like `bytearray`{.interpreted-text role="class"} and `memoryview`{.interpreted-text role="class"} types: only the exact `bytes`{.interpreted-text role="class"} type is accepted for bytes strings. (Contributed by Victor Stinner in `98393`{.interpreted-text role="gh"}.)

- `syslog.openlog`{.interpreted-text role="func"} and `syslog.closelog`{.interpreted-text role="func"} now fail if used in subinterpreters. `syslog.syslog`{.interpreted-text role="func"} may still be used in subinterpreters, but now only if `syslog.openlog`{.interpreted-text role="func"} 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`{.interpreted-text role="mod"} is a wrapper around process-global resources, which are best managed from the main interpreter. (Contributed by Donghee Na in `99127`{.interpreted-text role="gh"}.)

- The undocumented locking behavior of `~functools.cached_property`{.interpreted-text role="func"} is removed, because it locked across all instances of the class, leading to high lock contention. This means that a cached property getter function could now run more than once for a single instance, if two threads race. For most simple cached properties (e.g. those that are idempotent and simply calculate a value based on other attributes of the instance) this will be fine. If synchronization is needed, implement locking within the cached property getter function or around multi-threaded access points.

- `sys._current_exceptions`{.interpreted-text role="func"} now returns a mapping from thread-id to an exception instance, rather than to a `(typ, exc, tb)` tuple. (Contributed by Irit Katriel in `103176`{.interpreted-text role="gh"}.)

- When extracting tar files using `tarfile`{.interpreted-text role="mod"} or `shutil.unpack_archive`{.interpreted-text role="func"}, pass the *filter* argument to limit features that may be surprising or dangerous. See `tarfile-extraction-filter`{.interpreted-text role="ref"} for details.

- The output of the `tokenize.tokenize`{.interpreted-text role="func"} and `tokenize.generate_tokens`{.interpreted-text role="func"} functions is now changed due to the changes introduced in `701`{.interpreted-text role="pep"}. This means that `STRING` tokens are not emitted any more for f-strings and the tokens described in `701`{.interpreted-text role="pep"} are now produced instead: `FSTRING_START`, `FSTRING_MIDDLE` and `FSTRING_END` are now emitted for f-string \"string\" parts in addition to the appropriate tokens for the tokenization in the expression components. For example for the f-string `f"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 the changes required to support `701`{.interpreted-text role="pep"}. Some of these changes include:

  - The `type` attribute of the tokens emitted when tokenizing some invalid Python characters such as `!` has changed from `ERRORTOKEN` to `OP`.
  - Incomplete single-line strings now also raise `tokenize.TokenError`{.interpreted-text role="exc"} as incomplete multiline strings do.
  - Some incomplete or invalid Python code now raises `tokenize.TokenError`{.interpreted-text role="exc"} instead of returning arbitrary `ERRORTOKEN` tokens when tokenizing it.
  - Mixing tabs and spaces as indentation in the same file is not supported anymore and will raise a `TabError`{.interpreted-text role="exc"}.

- The `threading`{.interpreted-text role="mod"} module now expects the `!_thread`{.interpreted-text role="mod"} module to have an `_is_main_interpreter` attribute. It is a function with no arguments that returns `True` if the current interpreter is the main interpreter.

  Any library or application that provides a custom `_thread` module should provide `_is_main_interpreter()`. (See `112826`{.interpreted-text role="gh"}.)

## Build Changes

- Python no longer uses `setup.py`{.interpreted-text role="file"} to build shared C extension modules. Build parameters like headers and libraries are detected in `configure` script. Extensions are built by `Makefile`{.interpreted-text role="file"}. Most extensions use `pkg-config` and fall back to manual detection. (Contributed by Christian Heimes in `93939`{.interpreted-text role="gh"}.)

- `va_start()` with two parameters, like `va_start(args, format),` is now required to build Python. `va_start()` is no longer called with a single parameter. (Contributed by Kumar Aditya in `93207`{.interpreted-text role="gh"}.)

- CPython now uses the ThinLTO option as the default link time optimization policy if the Clang compiler accepts the flag. (Contributed by Donghee Na in `89536`{.interpreted-text role="gh"}.)

- Add `COMPILEALL_OPTS` variable in `Makefile`{.interpreted-text role="file"} to override `compileall`{.interpreted-text role="mod"} options (default: `-j0`) in `make install`. Also merged the 3 `compileall` commands into a single command to build .pyc files for all optimization levels (0, 1, 2) at once. (Contributed by Victor Stinner in `99289`{.interpreted-text role="gh"}.)

- Add platform triplets for 64-bit LoongArch:

  - loongarch64-linux-gnusf
  - loongarch64-linux-gnuf32
  - loongarch64-linux-gnu

  (Contributed by Zhang Na in `90656`{.interpreted-text role="gh"}.)

- `PYTHON_FOR_REGEN` now require Python 3.10 or newer.

- Autoconf 2.71 and aclocal 1.16.4 is now required to regenerate `configure`{.interpreted-text role="file"}. (Contributed by Christian Heimes in `89886`{.interpreted-text role="gh"}.)

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

## C API Changes

### New Features

::: {#whatsnew312-pep697}
- `697`{.interpreted-text role="pep"}: Introduce the `Unstable C API tier <unstable-c-api>`{.interpreted-text role="ref"}, intended for low-level tools like debuggers and JIT compilers. This API may change in each minor release of CPython without deprecation warnings. Its contents are marked by the `PyUnstable_` prefix in names.

  Code object constructors:

  - `PyUnstable_Code_New()` (renamed from `PyCode_New`)
  - `PyUnstable_Code_NewWithPosOnlyArgs()` (renamed from `PyCode_NewWithPosOnlyArgs`)

  Extra storage for code objects (`523`{.interpreted-text role="pep"}):

  - `PyUnstable_Eval_RequestCodeExtraIndex()` (renamed from `_PyEval_RequestCodeExtraIndex`)
  - `PyUnstable_Code_GetExtra()` (renamed from `_PyCode_GetExtra`)
  - `PyUnstable_Code_SetExtra()` (renamed from `_PyCode_SetExtra`)

  The original names will continue to be available until the respective API changes.

  (Contributed by Petr Viktorin in `101101`{.interpreted-text role="gh"}.)

- `697`{.interpreted-text role="pep"}: Add an API for extending types whose instance memory layout is opaque:

  - `PyType_Spec.basicsize`{.interpreted-text role="c:member"} can be zero or negative to specify inheriting or extending the base class size.
  - `PyObject_GetTypeData`{.interpreted-text role="c:func"} and `PyType_GetTypeDataSize`{.interpreted-text role="c:func"} added to allow access to subclass-specific instance data.
  - `Py_TPFLAGS_ITEMS_AT_END`{.interpreted-text role="c:macro"} and `PyObject_GetItemData`{.interpreted-text role="c:func"} added to allow safely extending certain variable-sized types, including `PyType_Type`{.interpreted-text role="c:var"}.
  - `Py_RELATIVE_OFFSET`{.interpreted-text role="c:macro"} added to allow defining `members <PyMemberDef>`{.interpreted-text role="c:type"} in terms of a subclass-specific struct.

  (Contributed by Petr Viktorin in `103509`{.interpreted-text role="gh"}.)

- Add the new `limited C API <limited-c-api>`{.interpreted-text role="ref"} function `PyType_FromMetaclass`{.interpreted-text role="c:func"}, which generalizes the existing `PyType_FromModuleAndSpec`{.interpreted-text role="c:func"} using an additional metaclass argument. (Contributed by Wenzel Jakob in `93012`{.interpreted-text role="gh"}.)

- API for creating objects that can be called using `the vectorcall protocol <vectorcall>`{.interpreted-text role="ref"} was added to the `Limited API <stable>`{.interpreted-text role="ref"}:

  - `Py_TPFLAGS_HAVE_VECTORCALL`{.interpreted-text role="c:macro"}
  - `PyVectorcall_NARGS`{.interpreted-text role="c:func"}
  - `PyVectorcall_Call`{.interpreted-text role="c:func"}
  - `vectorcallfunc`{.interpreted-text role="c:type"}

  The `Py_TPFLAGS_HAVE_VECTORCALL`{.interpreted-text role="c:macro"} flag is now removed from a class when the class\'s `~object.__call__`{.interpreted-text role="py:meth"} method is reassigned. This makes vectorcall safe to use with mutable types (i.e. heap types without the immutable flag, `Py_TPFLAGS_IMMUTABLETYPE`{.interpreted-text role="c:macro"}). Mutable types that do not override `~PyTypeObject.tp_call`{.interpreted-text role="c:member"} now inherit the `Py_TPFLAGS_HAVE_VECTORCALL` flag. (Contributed by Petr Viktorin in `93274`{.interpreted-text role="gh"}.)

  The `Py_TPFLAGS_MANAGED_DICT`{.interpreted-text role="c:macro"} and `Py_TPFLAGS_MANAGED_WEAKREF`{.interpreted-text role="c:macro"} flags have been added. This allows extensions classes to support object `~object.__dict__`{.interpreted-text role="attr"} and weakrefs with less bookkeeping, using less memory and with faster access.

- API for performing calls using `the vectorcall protocol <vectorcall>`{.interpreted-text role="ref"} was added to the `Limited API <stable>`{.interpreted-text role="ref"}:

  - `PyObject_Vectorcall`{.interpreted-text role="c:func"}
  - `PyObject_VectorcallMethod`{.interpreted-text role="c:func"}
  - `PY_VECTORCALL_ARGUMENTS_OFFSET`{.interpreted-text role="c:macro"}

  This means that both the incoming and outgoing ends of the vector call protocol are now available in the `Limited API <stable>`{.interpreted-text role="ref"}. (Contributed by Wenzel Jakob in `98586`{.interpreted-text role="gh"}.)

- Add two new public functions, `PyEval_SetProfileAllThreads`{.interpreted-text role="c:func"} and `PyEval_SetTraceAllThreads`{.interpreted-text role="c:func"}, that allow to set tracing and profiling functions in all running threads in addition to the calling one. (Contributed by Pablo Galindo in `93503`{.interpreted-text role="gh"}.)

- Add new function `PyFunction_SetVectorcall`{.interpreted-text role="c:func"} to the C API which sets the vectorcall field of a given `PyFunctionObject`{.interpreted-text role="c:type"}. (Contributed by Andrew Frost in `92257`{.interpreted-text role="gh"}.)

- The C API now permits registering callbacks via `PyDict_AddWatcher`{.interpreted-text role="c:func"}, `PyDict_Watch`{.interpreted-text role="c:func"} and related APIs to be called whenever a dictionary is modified. This is intended for use by optimizing interpreters, JIT compilers, or debuggers. (Contributed by Carl Meyer in `91052`{.interpreted-text role="gh"}.)

- Add `PyType_AddWatcher`{.interpreted-text role="c:func"} and `PyType_Watch`{.interpreted-text role="c:func"} API to register callbacks to receive notification on changes to a type. (Contributed by Carl Meyer in `91051`{.interpreted-text role="gh"}.)

- Add `PyCode_AddWatcher`{.interpreted-text role="c:func"} and `PyCode_ClearWatcher`{.interpreted-text role="c:func"} APIs to register callbacks to receive notification on creation and destruction of code objects. (Contributed by Itamar Oren in `91054`{.interpreted-text role="gh"}.)

- Add `PyFrame_GetVar`{.interpreted-text role="c:func"} and `PyFrame_GetVarString`{.interpreted-text role="c:func"} functions to get a frame variable by its name. (Contributed by Victor Stinner in `91248`{.interpreted-text role="gh"}.)

- Add `PyErr_GetRaisedException`{.interpreted-text role="c:func"} and `PyErr_SetRaisedException`{.interpreted-text role="c:func"} for saving and restoring the current exception. These functions return and accept a single exception object, rather than the triple arguments of the now-deprecated `PyErr_Fetch`{.interpreted-text role="c:func"} and `PyErr_Restore`{.interpreted-text role="c:func"}. This is less error prone and a bit more efficient. (Contributed by Mark Shannon in `101578`{.interpreted-text role="gh"}.)

- Add `_PyErr_ChainExceptions1`, which takes an exception instance, to replace the legacy-API `_PyErr_ChainExceptions`, which is now deprecated. (Contributed by Mark Shannon in `101578`{.interpreted-text role="gh"}.)

- Add `PyException_GetArgs`{.interpreted-text role="c:func"} and `PyException_SetArgs`{.interpreted-text role="c:func"} as convenience functions for retrieving and modifying the `~BaseException.args`{.interpreted-text role="attr"} passed to the exception\'s constructor. (Contributed by Mark Shannon in `101578`{.interpreted-text role="gh"}.)

- Add `PyErr_DisplayException`{.interpreted-text role="c:func"}, which takes an exception instance, to replace the legacy-api `!PyErr_Display`{.interpreted-text role="c:func"}. (Contributed by Irit Katriel in `102755`{.interpreted-text role="gh"}).
:::

::: {#whatsnew312-pep683}
- `683`{.interpreted-text role="pep"}: Introduce *Immortal Objects*, which allows objects to bypass reference counts, and related changes to the C-API:

  - 

    `_Py_IMMORTAL_REFCNT`: The reference count that defines an object

    :   as immortal.

  - `_Py_IsImmortal` Checks if an object has the immortal reference count.

  - 

    `PyObject_HEAD_INIT` This will now initialize reference count to

    :   `_Py_IMMORTAL_REFCNT` when used with `Py_BUILD_CORE`.

  - 

    `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` This returns the total number of unicode

    :   objects that have been interned. This is now needed for `refleak.py`{.interpreted-text role="file"} to correctly track reference counts and allocated blocks

  (Contributed by Eddie Elizondo in `84436`{.interpreted-text role="gh"}.)

- `684`{.interpreted-text role="pep"}: Add the new `Py_NewInterpreterFromConfig`{.interpreted-text role="c:func"} function and `PyInterpreterConfig`{.interpreted-text role="c:type"}, which may be used to create sub-interpreters with their own GILs. (See `whatsnew312-pep684`{.interpreted-text role="ref"} for more info.) (Contributed by Eric Snow in `104110`{.interpreted-text role="gh"}.)

- In the limited C API version 3.12, `Py_INCREF`{.interpreted-text role="c:func"} and `Py_DECREF`{.interpreted-text role="c:func"} functions are now implemented as opaque function calls to hide implementation details. (Contributed by Victor Stinner in `105387`{.interpreted-text role="gh"}.)
:::

### Porting to Python 3.12

- Legacy Unicode APIs based on `Py_UNICODE*` representation has been removed. Please migrate to APIs based on UTF-8 or `wchar_t*`.

- Argument parsing functions like `PyArg_ParseTuple`{.interpreted-text role="c:func"} doesn\'t support `Py_UNICODE*` based format (e.g. `u`, `Z`) anymore. Please migrate to other formats for Unicode like `s`, `z`, `es`, and `U`.

- `tp_weaklist` for all static builtin types is always `NULL`. This is an internal-only field on `PyTypeObject` but we\'re pointing out the change in case someone happens to be accessing the field directly anyway. To avoid breakage, consider using the existing public C-API instead, or, if necessary, the (internal-only) `_PyObject_GET_WEAKREFS_LISTPTR()` macro.

- This internal-only `PyTypeObject.tp_subclasses`{.interpreted-text role="c:member"} may now not be a valid object pointer. Its type was changed to `void *`{.interpreted-text role="c:expr"} to reflect this. We mention this in case someone happens to be accessing the internal-only field directly.

  To get a list of subclasses, call the Python method `~type.__subclasses__`{.interpreted-text role="py:meth"} (using `PyObject_CallMethod`{.interpreted-text role="c:func"}, for example).

- Add support of more formatting options (left aligning, octals, uppercase hexadecimals, `intmax_t`{.interpreted-text role="c:type"}, `ptrdiff_t`{.interpreted-text role="c:type"}, `wchar_t`{.interpreted-text role="c:type"} C strings, variable width and precision) in `PyUnicode_FromFormat`{.interpreted-text role="c:func"} and `PyUnicode_FromFormatV`{.interpreted-text role="c:func"}. (Contributed by Serhiy Storchaka in `98836`{.interpreted-text role="gh"}.)

- An unrecognized format character in `PyUnicode_FromFormat`{.interpreted-text role="c:func"} and `PyUnicode_FromFormatV`{.interpreted-text role="c:func"} now sets a `SystemError`{.interpreted-text role="exc"}. In previous versions it caused all the rest of the format string to be copied as-is to the result string, and any extra arguments discarded. (Contributed by Serhiy Storchaka in `95781`{.interpreted-text role="gh"}.)

- Fix wrong sign placement in `PyUnicode_FromFormat`{.interpreted-text role="c:func"} and `PyUnicode_FromFormatV`{.interpreted-text role="c:func"}. (Contributed by Philip Georgi in `95504`{.interpreted-text role="gh"}.)

- Extension classes wanting to add a `~object.__dict__`{.interpreted-text role="attr"} or weak reference slot should use `Py_TPFLAGS_MANAGED_DICT`{.interpreted-text role="c:macro"} and `Py_TPFLAGS_MANAGED_WEAKREF`{.interpreted-text role="c:macro"} instead of `tp_dictoffset` and `tp_weaklistoffset`, respectively. The use of `tp_dictoffset` and `tp_weaklistoffset` is still supported, but does not fully support multiple inheritance (`95589`{.interpreted-text role="gh"}), and performance may be worse. Classes declaring `Py_TPFLAGS_MANAGED_DICT`{.interpreted-text role="c:macro"} must call `!_PyObject_VisitManagedDict`{.interpreted-text role="c:func"} and `!_PyObject_ClearManagedDict`{.interpreted-text role="c:func"} to traverse and clear their instance\'s dictionaries. To clear weakrefs, call `PyObject_ClearWeakRefs`{.interpreted-text role="c:func"}, as before.

- The `PyUnicode_FSDecoder`{.interpreted-text role="c:func"} function no longer accepts bytes-like paths, like `bytearray`{.interpreted-text role="class"} and `memoryview`{.interpreted-text role="class"} types: only the exact `bytes`{.interpreted-text role="class"} type is accepted for bytes strings. (Contributed by Victor Stinner in `98393`{.interpreted-text role="gh"}.)

- The `Py_CLEAR`{.interpreted-text role="c:macro"}, `Py_SETREF`{.interpreted-text role="c:macro"} and `Py_XSETREF`{.interpreted-text role="c:macro"} macros now only evaluate their arguments once. If an argument has side effects, these side effects are no longer duplicated. (Contributed by Victor Stinner in `98724`{.interpreted-text role="gh"}.)

- The interpreter\'s error indicator is now always normalized. This means that `PyErr_SetObject`{.interpreted-text role="c:func"}, `PyErr_SetString`{.interpreted-text role="c:func"} and the other functions that set the error indicator now normalize the exception before storing it. (Contributed by Mark Shannon in `101578`{.interpreted-text role="gh"}.)

- `_Py_RefTotal` is no longer authoritative and only kept around for ABI compatibility. Note that it is an internal global and only available on debug builds. If you happen to be using it then you\'ll need to start using `_Py_GetGlobalRefTotal()`.

- The following functions now select an appropriate metaclass for the newly created type:

  - `PyType_FromSpec`{.interpreted-text role="c:func"}
  - `PyType_FromSpecWithBases`{.interpreted-text role="c:func"}
  - `PyType_FromModuleAndSpec`{.interpreted-text role="c:func"}

  Creating classes whose metaclass overrides `~PyTypeObject.tp_new`{.interpreted-text role="c:member"} is deprecated, and in Python 3.14+ it will be disallowed. Note that these functions ignore `tp_new` of the metaclass, possibly allowing incomplete initialization.

  Note that `PyType_FromMetaclass`{.interpreted-text role="c:func"} (added in Python 3.12) already disallows creating classes whose metaclass overrides `tp_new` (`~object.__new__`{.interpreted-text role="meth"} in Python).

  Since `tp_new` overrides almost everything `PyType_From*` functions do, the two are incompatible with each other. The existing behavior \-- ignoring the metaclass for several steps of type creation \-- is unsafe in general, since (meta)classes assume that `tp_new` was called. There is no simple general workaround. One of the following may work for you:

  - If you control the metaclass, avoid using `tp_new` in it:
    - If initialization can be skipped, it can be done in `~PyTypeObject.tp_init`{.interpreted-text role="c:member"} instead.
    - If the metaclass doesn\'t need to be instantiated from Python, set its `tp_new` to `NULL` using the `Py_TPFLAGS_DISALLOW_INSTANTIATION`{.interpreted-text role="c:macro"} flag. This makes it acceptable for `PyType_From*` functions.
  - Avoid `PyType_From*` functions: if you don\'t need C-specific features (slots or setting the instance size), create types by `calling <call>`{.interpreted-text role="ref"} the metaclass.
  - If you *know* the `tp_new` can be skipped safely, filter the deprecation warning out using `warnings.catch_warnings`{.interpreted-text role="func"} from Python.

- `PyOS_InputHook`{.interpreted-text role="c:var"} and `PyOS_ReadlineFunctionPointer`{.interpreted-text role="c:var"} are no longer called in `subinterpreters <sub-interpreter-support>`{.interpreted-text role="ref"}. This is because clients generally rely on process-wide global state (since these callbacks have no way of recovering extension module state).

  This also avoids situations where extensions may find themselves running in a subinterpreter that they don\'t support (or haven\'t yet been loaded in). See `104668`{.interpreted-text role="gh"} for more info.

- `PyLongObject`{.interpreted-text role="c:struct"} has had its internals changed for better performance. Although the internals of `PyLongObject`{.interpreted-text role="c:struct"} are private, they are used by some extension modules. The internal fields should no longer be accessed directly, instead the API functions beginning `PyLong_...` should be used instead. Two new *unstable* API functions are provided for efficient access to the value of `PyLongObject`{.interpreted-text role="c:struct"}s which fit into a single machine word:

  - `PyUnstable_Long_IsCompact`{.interpreted-text role="c:func"}
  - `PyUnstable_Long_CompactValue`{.interpreted-text role="c:func"}

- Custom allocators, set via `PyMem_SetAllocator`{.interpreted-text role="c:func"}, are now required to be thread-safe, regardless of memory domain. Allocators that don\'t have their own state, including \"hooks\", are not affected. If your custom allocator is not already thread-safe and you need guidance then please create a new GitHub issue and CC `@ericsnowcurrently`.

### Deprecated

- In accordance with `699`{.interpreted-text role="pep"}, the `ma_version_tag` field in `PyDictObject`{.interpreted-text role="c:type"} is deprecated for extension modules. Accessing this field will generate a compiler warning at compile time. This field will be removed in Python 3.14. (Contributed by Ramvikrams and Kumar Aditya in `101193`{.interpreted-text role="gh"}. PEP by Ken Jin.)

- Deprecate global configuration variable:

  - `Py_DebugFlag`{.interpreted-text role="c:var"}: use `PyConfig.parser_debug`{.interpreted-text role="c:member"}
  - `Py_VerboseFlag`{.interpreted-text role="c:var"}: use `PyConfig.verbose`{.interpreted-text role="c:member"}
  - `Py_QuietFlag`{.interpreted-text role="c:var"}: use `PyConfig.quiet`{.interpreted-text role="c:member"}
  - `Py_InteractiveFlag`{.interpreted-text role="c:var"}: use `PyConfig.interactive`{.interpreted-text role="c:member"}
  - `Py_InspectFlag`{.interpreted-text role="c:var"}: use `PyConfig.inspect`{.interpreted-text role="c:member"}
  - `Py_OptimizeFlag`{.interpreted-text role="c:var"}: use `PyConfig.optimization_level`{.interpreted-text role="c:member"}
  - `Py_NoSiteFlag`{.interpreted-text role="c:var"}: use `PyConfig.site_import`{.interpreted-text role="c:member"}
  - `Py_BytesWarningFlag`{.interpreted-text role="c:var"}: use `PyConfig.bytes_warning`{.interpreted-text role="c:member"}
  - `Py_FrozenFlag`{.interpreted-text role="c:var"}: use `PyConfig.pathconfig_warnings`{.interpreted-text role="c:member"}
  - `Py_IgnoreEnvironmentFlag`{.interpreted-text role="c:var"}: use `PyConfig.use_environment`{.interpreted-text role="c:member"}
  - `Py_DontWriteBytecodeFlag`{.interpreted-text role="c:var"}: use `PyConfig.write_bytecode`{.interpreted-text role="c:member"}
  - `Py_NoUserSiteDirectory`{.interpreted-text role="c:var"}: use `PyConfig.user_site_directory`{.interpreted-text role="c:member"}
  - `Py_UnbufferedStdioFlag`{.interpreted-text role="c:var"}: use `PyConfig.buffered_stdio`{.interpreted-text role="c:member"}
  - `Py_HashRandomizationFlag`{.interpreted-text role="c:var"}: use `PyConfig.use_hash_seed`{.interpreted-text role="c:member"} and `PyConfig.hash_seed`{.interpreted-text role="c:member"}
  - `Py_IsolatedFlag`{.interpreted-text role="c:var"}: use `PyConfig.isolated`{.interpreted-text role="c:member"}
  - `Py_LegacyWindowsFSEncodingFlag`{.interpreted-text role="c:var"}: use `PyPreConfig.legacy_windows_fs_encoding`{.interpreted-text role="c:member"}
  - `Py_LegacyWindowsStdioFlag`{.interpreted-text role="c:var"}: use `PyConfig.legacy_windows_stdio`{.interpreted-text role="c:member"}
  - `!Py_FileSystemDefaultEncoding`{.interpreted-text role="c:var"}: use `PyConfig.filesystem_encoding`{.interpreted-text role="c:member"}
  - `!Py_HasFileSystemDefaultEncoding`{.interpreted-text role="c:var"}: use `PyConfig.filesystem_encoding`{.interpreted-text role="c:member"}
  - `!Py_FileSystemDefaultEncodeErrors`{.interpreted-text role="c:var"}: use `PyConfig.filesystem_errors`{.interpreted-text role="c:member"}
  - `!Py_UTF8Mode`{.interpreted-text role="c:var"}: use `PyPreConfig.utf8_mode`{.interpreted-text role="c:member"} (see `Py_PreInitialize`{.interpreted-text role="c:func"})

  The `Py_InitializeFromConfig`{.interpreted-text role="c:func"} API should be used with `PyConfig`{.interpreted-text role="c:type"} instead. (Contributed by Victor Stinner in `77782`{.interpreted-text role="gh"}.)

- Creating `immutable types <Py_TPFLAGS_IMMUTABLETYPE>`{.interpreted-text role="c:data"} with mutable bases is deprecated and will be disabled in Python 3.14. (`95388`{.interpreted-text role="gh"})

- The `structmember.h`{.interpreted-text role="file"} header is deprecated, though it continues to be available and there are no plans to remove it.

  Its contents are now available just by including `Python.h`{.interpreted-text role="file"}, with a `Py` prefix added if it was missing:

  - `PyMemberDef`{.interpreted-text role="c:struct"}, `PyMember_GetOne`{.interpreted-text role="c:func"} and `PyMember_SetOne`{.interpreted-text role="c:func"}
  - Type macros like `Py_T_INT`{.interpreted-text role="c:macro"}, `Py_T_DOUBLE`{.interpreted-text role="c:macro"}, etc. (previously `T_INT`, `T_DOUBLE`, etc.)
  - The flags `Py_READONLY`{.interpreted-text role="c:macro"} (previously `READONLY`) and `Py_AUDIT_READ`{.interpreted-text role="c:macro"} (previously all uppercase)

  Several items are not exposed from `Python.h`{.interpreted-text role="file"}:

  - `T_OBJECT`{.interpreted-text role="c:macro"} (use `Py_T_OBJECT_EX`{.interpreted-text role="c:macro"})
  - `T_NONE`{.interpreted-text role="c:macro"} (previously undocumented, and pretty quirky)
  - The macro `WRITE_RESTRICTED` which does nothing.
  - The macros `RESTRICTED` and `READ_RESTRICTED`, equivalents of `Py_AUDIT_READ`{.interpreted-text role="c:macro"}.
  - In some configurations, `<stddef.h>` is not included from `Python.h`{.interpreted-text role="file"}. It should be included manually when using `offsetof()`.

  The deprecated header continues to provide its original contents under the original names. Your old code can stay unchanged, unless the extra include and non-namespaced macros bother you greatly.

  (Contributed in `47146`{.interpreted-text role="gh"} by Petr Viktorin, based on earlier work by Alexander Belopolsky and Matthias Braun.)

- `PyErr_Fetch`{.interpreted-text role="c:func"} and `PyErr_Restore`{.interpreted-text role="c:func"} are deprecated. Use `PyErr_GetRaisedException`{.interpreted-text role="c:func"} and `PyErr_SetRaisedException`{.interpreted-text role="c:func"} instead. (Contributed by Mark Shannon in `101578`{.interpreted-text role="gh"}.)

- `!PyErr_Display`{.interpreted-text role="c:func"} is deprecated. Use `PyErr_DisplayException`{.interpreted-text role="c:func"} instead. (Contributed by Irit Katriel in `102755`{.interpreted-text role="gh"}).

- `_PyErr_ChainExceptions` is deprecated. Use `_PyErr_ChainExceptions1` instead. (Contributed by Irit Katriel in `102192`{.interpreted-text role="gh"}.)

- Using `PyType_FromSpec`{.interpreted-text role="c:func"}, `PyType_FromSpecWithBases`{.interpreted-text role="c:func"} or `PyType_FromModuleAndSpec`{.interpreted-text role="c:func"} to create a class whose metaclass overrides `~PyTypeObject.tp_new`{.interpreted-text role="c:member"} is deprecated. Call the metaclass instead.

#### Pending removal in Python 3.14

- The `ma_version_tag` field in `PyDictObject`{.interpreted-text role="c:type"} for extension modules (`699`{.interpreted-text role="pep"}; `101193`{.interpreted-text role="gh"}).
- Creating `immutable types <Py_TPFLAGS_IMMUTABLETYPE>`{.interpreted-text role="c:data"} with mutable bases (`95388`{.interpreted-text role="gh"}).

#### Pending removal in Python 3.15

- The `!PyImport_ImportModuleNoBlock`{.interpreted-text role="c:func"}: Use `PyImport_ImportModule`{.interpreted-text role="c:func"} instead.

- `!PyWeakref_GetObject`{.interpreted-text role="c:func"} and `!PyWeakref_GET_OBJECT`{.interpreted-text role="c:func"}: Use `PyWeakref_GetRef`{.interpreted-text role="c:func"} instead. The [pythoncapi-compat project](https://github.com/python/pythoncapi-compat/) can be used to get `PyWeakref_GetRef`{.interpreted-text role="c:func"} on Python 3.12 and older.

- `Py_UNICODE`{.interpreted-text role="c:type"} type and the `!Py_UNICODE_WIDE`{.interpreted-text role="c:macro"} macro: Use `wchar_t`{.interpreted-text role="c:type"} instead.

- `!PyUnicode_AsDecodedObject`{.interpreted-text role="c:func"}: Use `PyCodec_Decode`{.interpreted-text role="c:func"} instead.

- `!PyUnicode_AsDecodedUnicode`{.interpreted-text role="c:func"}: Use `PyCodec_Decode`{.interpreted-text role="c:func"} instead; Note that some codecs (for example, \"base64\") may return a type other than `str`{.interpreted-text role="class"}, such as `bytes`{.interpreted-text role="class"}.

- `!PyUnicode_AsEncodedObject`{.interpreted-text role="c:func"}: Use `PyCodec_Encode`{.interpreted-text role="c:func"} instead.

- `!PyUnicode_AsEncodedUnicode`{.interpreted-text role="c:func"}: Use `PyCodec_Encode`{.interpreted-text role="c:func"} instead; Note that some codecs (for example, \"base64\") may return a type other than `bytes`{.interpreted-text role="class"}, such as `str`{.interpreted-text role="class"}.

- Python initialization functions, deprecated in Python 3.13:

  - `!Py_GetPath`{.interpreted-text role="c:func"}: Use `PyConfig_Get("module_search_paths") <PyConfig_Get>`{.interpreted-text role="c:func"} (`sys.path`{.interpreted-text role="data"}) instead.
  - `!Py_GetPrefix`{.interpreted-text role="c:func"}: Use `PyConfig_Get("base_prefix") <PyConfig_Get>`{.interpreted-text role="c:func"} (`sys.base_prefix`{.interpreted-text role="data"}) instead. Use `PyConfig_Get("prefix")
    <PyConfig_Get>`{.interpreted-text role="c:func"} (`sys.prefix`{.interpreted-text role="data"}) if `virtual environments
    <venv-def>`{.interpreted-text role="ref"} need to be handled.
  - `!Py_GetExecPrefix`{.interpreted-text role="c:func"}: Use `PyConfig_Get("base_exec_prefix") <PyConfig_Get>`{.interpreted-text role="c:func"} (`sys.base_exec_prefix`{.interpreted-text role="data"}) instead. Use `PyConfig_Get("exec_prefix") <PyConfig_Get>`{.interpreted-text role="c:func"} (`sys.exec_prefix`{.interpreted-text role="data"}) if `virtual environments <venv-def>`{.interpreted-text role="ref"} need to be handled.
  - `!Py_GetProgramFullPath`{.interpreted-text role="c:func"}: Use `PyConfig_Get("executable") <PyConfig_Get>`{.interpreted-text role="c:func"} (`sys.executable`{.interpreted-text role="data"}) instead.
  - `!Py_GetProgramName`{.interpreted-text role="c:func"}: Use `PyConfig_Get("executable") <PyConfig_Get>`{.interpreted-text role="c:func"} (`sys.executable`{.interpreted-text role="data"}) instead.
  - `!Py_GetPythonHome`{.interpreted-text role="c:func"}: Use `PyConfig_Get("home") <PyConfig_Get>`{.interpreted-text role="c:func"} or the `PYTHONHOME`{.interpreted-text role="envvar"} environment variable instead.

  The [pythoncapi-compat project](https://github.com/python/pythoncapi-compat/) can be used to get `PyConfig_Get`{.interpreted-text role="c:func"} on Python 3.13 and older.

- Functions to configure Python\'s initialization, deprecated in Python 3.11:

  - `!PySys_SetArgvEx()`{.interpreted-text role="c:func"}: Set `PyConfig.argv`{.interpreted-text role="c:member"} instead.
  - `!PySys_SetArgv()`{.interpreted-text role="c:func"}: Set `PyConfig.argv`{.interpreted-text role="c:member"} instead.
  - `!Py_SetProgramName()`{.interpreted-text role="c:func"}: Set `PyConfig.program_name`{.interpreted-text role="c:member"} instead.
  - `!Py_SetPythonHome()`{.interpreted-text role="c:func"}: Set `PyConfig.home`{.interpreted-text role="c:member"} instead.
  - `!PySys_ResetWarnOptions`{.interpreted-text role="c:func"}: Clear `sys.warnoptions`{.interpreted-text role="data"} and `!warnings.filters`{.interpreted-text role="data"} instead.

  The `Py_InitializeFromConfig`{.interpreted-text role="c:func"} API should be used with `PyConfig`{.interpreted-text role="c:type"} instead.

- Global configuration variables:

  - `Py_DebugFlag`{.interpreted-text role="c:var"}: Use `PyConfig.parser_debug`{.interpreted-text role="c:member"} or `PyConfig_Get("parser_debug") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `Py_VerboseFlag`{.interpreted-text role="c:var"}: Use `PyConfig.verbose`{.interpreted-text role="c:member"} or `PyConfig_Get("verbose") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `Py_QuietFlag`{.interpreted-text role="c:var"}: Use `PyConfig.quiet`{.interpreted-text role="c:member"} or `PyConfig_Get("quiet") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `Py_InteractiveFlag`{.interpreted-text role="c:var"}: Use `PyConfig.interactive`{.interpreted-text role="c:member"} or `PyConfig_Get("interactive") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `Py_InspectFlag`{.interpreted-text role="c:var"}: Use `PyConfig.inspect`{.interpreted-text role="c:member"} or `PyConfig_Get("inspect") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `Py_OptimizeFlag`{.interpreted-text role="c:var"}: Use `PyConfig.optimization_level`{.interpreted-text role="c:member"} or `PyConfig_Get("optimization_level") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `Py_NoSiteFlag`{.interpreted-text role="c:var"}: Use `PyConfig.site_import`{.interpreted-text role="c:member"} or `PyConfig_Get("site_import") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `Py_BytesWarningFlag`{.interpreted-text role="c:var"}: Use `PyConfig.bytes_warning`{.interpreted-text role="c:member"} or `PyConfig_Get("bytes_warning") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `Py_FrozenFlag`{.interpreted-text role="c:var"}: Use `PyConfig.pathconfig_warnings`{.interpreted-text role="c:member"} or `PyConfig_Get("pathconfig_warnings") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `Py_IgnoreEnvironmentFlag`{.interpreted-text role="c:var"}: Use `PyConfig.use_environment`{.interpreted-text role="c:member"} or `PyConfig_Get("use_environment") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `Py_DontWriteBytecodeFlag`{.interpreted-text role="c:var"}: Use `PyConfig.write_bytecode`{.interpreted-text role="c:member"} or `PyConfig_Get("write_bytecode") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `Py_NoUserSiteDirectory`{.interpreted-text role="c:var"}: Use `PyConfig.user_site_directory`{.interpreted-text role="c:member"} or `PyConfig_Get("user_site_directory") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `Py_UnbufferedStdioFlag`{.interpreted-text role="c:var"}: Use `PyConfig.buffered_stdio`{.interpreted-text role="c:member"} or `PyConfig_Get("buffered_stdio") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `Py_HashRandomizationFlag`{.interpreted-text role="c:var"}: Use `PyConfig.use_hash_seed`{.interpreted-text role="c:member"} and `PyConfig.hash_seed`{.interpreted-text role="c:member"} or `PyConfig_Get("hash_seed") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `Py_IsolatedFlag`{.interpreted-text role="c:var"}: Use `PyConfig.isolated`{.interpreted-text role="c:member"} or `PyConfig_Get("isolated") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `Py_LegacyWindowsFSEncodingFlag`{.interpreted-text role="c:var"}: Use `PyPreConfig.legacy_windows_fs_encoding`{.interpreted-text role="c:member"} or `PyConfig_Get("legacy_windows_fs_encoding") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `Py_LegacyWindowsStdioFlag`{.interpreted-text role="c:var"}: Use `PyConfig.legacy_windows_stdio`{.interpreted-text role="c:member"} or `PyConfig_Get("legacy_windows_stdio") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `!Py_FileSystemDefaultEncoding`{.interpreted-text role="c:var"}, `!Py_HasFileSystemDefaultEncoding`{.interpreted-text role="c:var"}: Use `PyConfig.filesystem_encoding`{.interpreted-text role="c:member"} or `PyConfig_Get("filesystem_encoding") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `!Py_FileSystemDefaultEncodeErrors`{.interpreted-text role="c:var"}: Use `PyConfig.filesystem_errors`{.interpreted-text role="c:member"} or `PyConfig_Get("filesystem_errors") <PyConfig_Get>`{.interpreted-text role="c:func"} instead.
  - `!Py_UTF8Mode`{.interpreted-text role="c:var"}: Use `PyPreConfig.utf8_mode`{.interpreted-text role="c:member"} or `PyConfig_Get("utf8_mode") <PyConfig_Get>`{.interpreted-text role="c:func"} instead. (see `Py_PreInitialize`{.interpreted-text role="c:func"})

  The `Py_InitializeFromConfig`{.interpreted-text role="c:func"} API should be used with `PyConfig`{.interpreted-text role="c:type"} to set these options. Or `PyConfig_Get`{.interpreted-text role="c:func"} can be used to get these options at runtime.

#### Pending removal in Python 3.16

- The bundled copy of `libmpdec`.

#### Pending removal in future versions

The following APIs are deprecated and will be removed, although there is currently no date scheduled for their removal.

- `Py_TPFLAGS_HAVE_FINALIZE`{.interpreted-text role="c:macro"}: Unneeded since Python 3.8.
- `PyErr_Fetch`{.interpreted-text role="c:func"}: Use `PyErr_GetRaisedException`{.interpreted-text role="c:func"} instead.
- `PyErr_NormalizeException`{.interpreted-text role="c:func"}: Use `PyErr_GetRaisedException`{.interpreted-text role="c:func"} instead.
- `PyErr_Restore`{.interpreted-text role="c:func"}: Use `PyErr_SetRaisedException`{.interpreted-text role="c:func"} instead.
- `PyModule_GetFilename`{.interpreted-text role="c:func"}: Use `PyModule_GetFilenameObject`{.interpreted-text role="c:func"} instead.
- `PyOS_AfterFork`{.interpreted-text role="c:func"}: Use `PyOS_AfterFork_Child`{.interpreted-text role="c:func"} instead.
- `PySlice_GetIndicesEx`{.interpreted-text role="c:func"}: Use `PySlice_Unpack`{.interpreted-text role="c:func"} and `PySlice_AdjustIndices`{.interpreted-text role="c:func"} instead.
- `PyUnicode_READY`{.interpreted-text role="c:func"}: Unneeded since Python 3.12
- `!PyErr_Display`{.interpreted-text role="c:func"}: Use `PyErr_DisplayException`{.interpreted-text role="c:func"} instead.
- `!_PyErr_ChainExceptions`{.interpreted-text role="c:func"}: Use `!_PyErr_ChainExceptions1`{.interpreted-text role="c:func"} instead.
- `!PyBytesObject.ob_shash`{.interpreted-text role="c:member"} member: call `PyObject_Hash`{.interpreted-text role="c:func"} instead.
- Thread Local Storage (TLS) API:
  - `PyThread_create_key`{.interpreted-text role="c:func"}: Use `PyThread_tss_alloc`{.interpreted-text role="c:func"} instead.
  - `PyThread_delete_key`{.interpreted-text role="c:func"}: Use `PyThread_tss_free`{.interpreted-text role="c:func"} instead.
  - `PyThread_set_key_value`{.interpreted-text role="c:func"}: Use `PyThread_tss_set`{.interpreted-text role="c:func"} instead.
  - `PyThread_get_key_value`{.interpreted-text role="c:func"}: Use `PyThread_tss_get`{.interpreted-text role="c:func"} instead.
  - `PyThread_delete_key_value`{.interpreted-text role="c:func"}: Use `PyThread_tss_delete`{.interpreted-text role="c:func"} instead.
  - `PyThread_ReInitTLS`{.interpreted-text role="c:func"}: Unneeded since Python 3.7.

### Removed

- Remove the `token.h`{.interpreted-text role="file"} header file. There was never any public tokenizer C API. The `token.h`{.interpreted-text role="file"} header file was only designed to be used by Python internals. (Contributed by Victor Stinner in `92651`{.interpreted-text role="gh"}.)
- Legacy Unicode APIs have been removed. See `623`{.interpreted-text role="pep"} for detail.
  - `!PyUnicode_WCHAR_KIND`{.interpreted-text role="c:macro"}
  - `!PyUnicode_AS_UNICODE`{.interpreted-text role="c:func"}
  - `!PyUnicode_AsUnicode`{.interpreted-text role="c:func"}
  - `!PyUnicode_AsUnicodeAndSize`{.interpreted-text role="c:func"}
  - `!PyUnicode_AS_DATA`{.interpreted-text role="c:func"}
  - `!PyUnicode_FromUnicode`{.interpreted-text role="c:func"}
  - `!PyUnicode_GET_SIZE`{.interpreted-text role="c:func"}
  - `!PyUnicode_GetSize`{.interpreted-text role="c:func"}
  - `!PyUnicode_GET_DATA_SIZE`{.interpreted-text role="c:func"}
- Remove the `PyUnicode_InternImmortal()` function macro. (Contributed by Victor Stinner in `85858`{.interpreted-text role="gh"}.)