What’s New In Python 3.13

Release:

3.13.0a0

Date:

May 31, 2023

This article explains the new features in Python 3.13, compared to 3.12.

For full details, see the changelog.

Note

Prerelease users should be aware that this document is currently in draft form. It will be updated substantially as Python 3.13 moves towards release, so it’s worth checking back even after reading earlier versions.

Summary – Release highlights

New Features

Other Language Changes

New Modules

• None yet.

Improved Modules

io

The io.IOBase finalizer now logs the close() method errors with sys.unraisablehook. Previously, errors were ignored silently by default, and only logged in Python Development Mode or on Python built on debug mode. (Contributed by Victor Stinner in gh-62948.)

pathlib

• Add support for recursive wildcards in pathlib.PurePath.match(). (Contributed by Barney Gale in gh-73435.)

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

Optimizations

Deprecated

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

Removed

• PEP 594: Remove the telnetlib module, deprecated in Python 3.11: use the projects telnetlib3 or Exscript instead. (Contributed by Victor Stinner in gh-104773.)

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

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

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

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

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

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

• Removed the following unittest functions, deprecated in Python 3.11:

  • unittest.findTestCases()

  • unittest.makeSuite()

  • unittest.getTestCaseNames()

  Use TestLoader methods instead:

  • unittest.TestLoader.loadTestsFromModule()

  • unittest.TestLoader.loadTestsFromTestCase()

  • unittest.TestLoader.getTestCaseNames()

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

• PEP 594: Remove the cgi and cgitb modules, deprecated in Python 3.11.

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

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

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

  • cgi.parse_header() can be replaced with the functionality in the email package, which implements the same MIME RFCs. For example, with email.message.EmailMessage:

    from email.message import EmailMessage
    msg = EmailMessage()
    msg['content-type'] = 'application/json; charset="utf8"'
    main, params = msg.get_content_type(), msg['content-type'].params
    

  (Contributed by Victor Stinner in gh-104773.)

• PEP 594: Remove the sndhdr module, deprecated in Python 3.11: use the projects filetype, puremagic, or python-magic instead. (Contributed by Victor Stinner in gh-104773.)

• PEP 594: Remove the pipes module, deprecated in Python 3.11: use the subprocess module instead. (Contributed by Victor Stinner in gh-104773.)

• PEP 594: Remove the ossaudiodev module, deprecated in Python 3.11: use the pygame project for audio playback. (Contributed by Victor Stinner in gh-104780.)

• PEP 594: Remove the sunau module, deprecated in Python 3.11. (Contributed by Victor Stinner in gh-104773.)

• PEP 594: Remove the mailcap module, deprecated in Python 3.11. The mimetypes module provides an alternative. (Contributed by Victor Stinner in gh-104773.)

• PEP 594: Remove the spwd module, deprecated in Python 3.11: the python-pam project can be used instead. (Contributed by Victor Stinner in gh-104773.)

• PEP 594: Remove the nntplib module, deprecated in Python 3.11: the PyPI nntplib project can be used instead. (Contributed by Victor Stinner in gh-104773.)

• PEP 594: Remove the nis module, deprecated in Python 3.11. (Contributed by Victor Stinner in gh-104773.)

• PEP 594: Remove the xdrlib module, deprecated in Python 3.11. (Contributed by Victor Stinner in gh-104773.)

• PEP 594: Remove the msilib module, deprecated in Python 3.11. (Contributed by Zachary Ware in gh-104773.)

• PEP 594: Remove the crypt module and its private _crypt extension, deprecated in Python 3.11. The hashlib module is a potential replacement for certain use cases. Otherwise, the following PyPI projects can be used:

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

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

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

  • legacycrypt: Wrapper to the POSIX crypt library call and associated functionality.

  (Contributed by Victor Stinner in gh-104773.)

• PEP 594: Remove the uu module, deprecated in Python 3.11: the base64 module is a modern alternative. (Contributed by Victor Stinner in gh-104773.)

• PEP 594: Remove the aifc module, deprecated in Python 3.11. (Contributed by Victor Stinner in gh-104773.)

• PEP 594: Remove the audioop module, deprecated in Python 3.11. (Contributed by Victor Stinner in gh-104773.)

• PEP 594: Remove the chunk module, deprecated in Python 3.11. (Contributed by Victor Stinner in gh-104773.)

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

• PEP 594: Remove the imghdr module, deprecated in Python 3.11: use the projects filetype, puremagic, or python-magic instead. (Contributed by Victor Stinner in gh-104773.)

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

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

• Remove the old trashcan macros Py_TRASHCAN_SAFE_BEGIN and Py_TRASHCAN_SAFE_END. They should be replaced by the new macros Py_TRASHCAN_BEGIN and Py_TRASHCAN_END. The new macros were added in Python 3.8 and the old macros were deprecated in Python 3.11. (Contributed by Irit Katriel in gh-105111.)

Porting to Python 3.13

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

• The old trashcan macros Py_TRASHCAN_SAFE_BEGIN and Py_TRASHCAN_SAFE_END were removed. They should be replaced by the new macros Py_TRASHCAN_BEGIN and Py_TRASHCAN_END.

  A tp_dealloc function that has the old macros, such as:

  static void
  mytype_dealloc(mytype *p)
  {
      PyObject_GC_UnTrack(p);
      Py_TRASHCAN_SAFE_BEGIN(p);
      ...
      Py_TRASHCAN_SAFE_END
  }
  

  should migrate to the new macros as follows:

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

  Note that Py_TRASHCAN_BEGIN has a second argument which should be the deallocation function it is in.

Build Changes

C API Changes

New Features

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

Porting to Python 3.13

Deprecated

Removed

• Remove functions deprecated in Python 3.9.

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

  • PyEval_CallFunction(): use PyObject_CallFunction() instead.

  • PyEval_CallMethod(): use PyObject_CallMethod() instead.

  (Contributed by Victor Stinner in gh-105107.)