May 17, 2025 · May 17, 2025
diff --git a/Doc/deprecations/pending-removal-in-3.15.rst b/Doc/deprecations/pending-removal-in-3.15.rst

 * :class:`locale`:

  * The :func:`~locale.getdefaultlocale` function
  * The :func:`!~locale.getdefaultlocale` function
    has been deprecated since Python 3.11.
    Its removal was originally planned for Python 3.13 (:gh:`90817`),
    but has been postponed to Python 3.15.
diff --git a/Doc/library/locale.rst b/Doc/library/locale.rst
      The function now temporarily sets the ``LC_CTYPE`` locale in some cases.


 .. function:: getdefaultlocale([envvars])

   Tries to determine the default locale settings and returns them as a tuple of
   the form ``(language code, encoding)``.

   According to POSIX, a program which has not called ``setlocale(LC_ALL, '')``
   runs using the portable ``'C'`` locale.  Calling ``setlocale(LC_ALL, '')`` lets
   it use the default locale as defined by the :envvar:`LANG` variable.  Since we
   do not want to interfere with the current locale setting we thus emulate the
   behavior in the way described above.

   To maintain compatibility with other platforms, not only the :envvar:`LANG`
   variable is tested, but a list of variables given as envvars parameter.  The
   first found to be defined will be used.  *envvars* defaults to the search
   path used in GNU gettext; it must always contain the variable name
   ``'LANG'``.  The GNU gettext search path contains ``'LC_ALL'``,
   ``'LC_CTYPE'``, ``'LANG'`` and ``'LANGUAGE'``, in that order.

   Except for the code ``'C'``, the language code corresponds to :rfc:`1766`.
   *language code* and *encoding* may be ``None`` if their values cannot be
   determined.

   .. deprecated-removed:: 3.11 3.15


 .. function:: getlocale(category=LC_CTYPE)

   Returns the current setting for the given locale category as sequence containing
diff --git a/Doc/using/cmdline.rst b/Doc/using/cmdline.rst
   components running in the same process (such as the GNU ``readline``
   library), the updated setting is also seen in subprocesses (regardless of
   whether or not those processes are running a Python interpreter), as well as
   in operations that query the environment rather than the current C locale
   (such as Python's own :func:`locale.getdefaultlocale`).
   in operations that query the environment rather than the current C locale.

   Configuring one of these locales (either explicitly or via the above
   implicit locale coercion) automatically enables the ``surrogateescape``
diff --git a/Doc/whatsnew/3.11.rst b/Doc/whatsnew/3.11.rst
  * :func:`!importlib.resources.read_text`
  * :func:`!importlib.resources.path`

 * The :func:`locale.getdefaultlocale` function is deprecated and will be
 * The :func:`!locale.getdefaultlocale` function is deprecated and will be
  removed in Python 3.15. Use :func:`locale.setlocale`,
  :func:`locale.getpreferredencoding(False) <locale.getpreferredencoding>` and
  :func:`locale.getlocale` functions instead.

 * :mod:`calendar`: The :class:`calendar.LocaleTextCalendar` and
  :class:`calendar.LocaleHTMLCalendar` classes now use
  :func:`locale.getlocale`, instead of using :func:`locale.getdefaultlocale`,
  :func:`locale.getlocale`, instead of using :func:`!locale.getdefaultlocale`,
  if no locale is specified.
  (Contributed by Victor Stinner in :issue:`46659`.)

diff --git a/Doc/whatsnew/3.15.rst b/Doc/whatsnew/3.15.rst
 Removed
 =======


 locale
 ------
 * Remove the :func:`!locale.getdefaultlocale` function,
  which was deprecated since Python 3.13.
  (Contributed by Stan Ulbrych in :gh:`XXXXXX`.)


 platform
 --------

diff --git a/Lib/locale.py b/Lib/locale.py

 # Yuck:  LC_MESSAGES is non-standard:  can't tell whether it exists before
 # trying the import.  So __all__ is also fiddled at the end of the file.
 __all__ = ["getlocale", "getdefaultlocale", "getpreferredencoding", "Error",
 __all__ = ["getlocale", "getpreferredencoding", "Error",
           "setlocale", "localeconv", "strcoll", "strxfrm",
           "str", "atof", "atoi", "format_string", "currency",
           "normalize", "LC_CTYPE", "LC_COLLATE", "LC_TIME", "LC_MONETARY",
        raise TypeError('Locale must be None, a string, or an iterable of '
                        'two strings -- language code, encoding.') from None

 def getdefaultlocale(envvars=('LC_ALL', 'LC_CTYPE', 'LANG', 'LANGUAGE')):

    """ Tries to determine the default locale settings and returns
        them as tuple (language code, encoding).

        According to POSIX, a program which has not called
        setlocale(LC_ALL, "") runs using the portable 'C' locale.
        Calling setlocale(LC_ALL, "") lets it use the default locale as
        defined by the LANG variable. Since we don't want to interfere
        with the current locale setting we thus emulate the behavior
        in the way described above.

        To maintain compatibility with other platforms, not only the
        LANG variable is tested, but a list of variables given as
        envvars parameter. The first found to be defined will be
        used. envvars defaults to the search path used in GNU gettext;
        it must always contain the variable name 'LANG'.

        Except for the code 'C', the language code corresponds to RFC
        1766.  code and encoding can be None in case the values cannot
        be determined.

    """

    import warnings
    warnings._deprecated(
        "locale.getdefaultlocale",
        "{name!r} is deprecated and slated for removal in Python {remove}. "
        "Use setlocale(), getencoding() and getlocale() instead.",
        remove=(3, 15))
    return _getdefaultlocale(envvars)


 def _getdefaultlocale(envvars=('LC_ALL', 'LC_CTYPE', 'LANG', 'LANGUAGE')):
    try:
        # check if it's supported by the _locale module
        import _locale
        code, encoding = _locale._getdefaultlocale()
    except (ImportError, AttributeError):
        pass
    else:
        # make sure the code/encoding values are valid
        if sys.platform == "win32" and code and code[:2] == "0x":
            # map windows language identifier to language name
            code = windows_locale.get(int(code, 0))
        # ...add other platform-specific processing here, if
        # necessary...
        return code, encoding

    # fall back on POSIX behaviour
    import os
    lookup = os.environ.get
    for variable in envvars:
        localename = lookup(variable,None)
        if localename:
            if variable == 'LANGUAGE':
                localename = localename.split(':')[0]
            break
    else:
        localename = 'C'
    return _parse_localename(localename)


 def getlocale(category=LC_CTYPE):

    """ Returns the current setting for the given locale category as
    _init_categories()
    del categories['LC_ALL']

    print('Locale defaults as determined bygetdefaultlocale():')
    print('Locale defaults as determined bylocale.getlocale() and locale.getpreferredencoding():')
    print('-'*72)
    lang, enc = getdefaultlocale()
    print('Language: ', lang or '(undefined)')
    print('Encoding: ', enc or '(undefined)')
    print()
    lang, enc = getlocale()
    print(f'Language: {lang or "(undefined)"}')
    print(f'Encoding: {enc or getpreferredencoding(False) or "(undefined)"}\n')

    print('Locale settings on startup:')
    print('-'*72)
diff --git a/Lib/test/test_locale.py b/Lib/test/test_locale.py


 class TestMiscellaneous(unittest.TestCase):
    def test_defaults_UTF8(self):
        # Issue #18378: on (at least) macOS setting LC_CTYPE to "UTF-8" is
        # valid. Furthermore LC_CTYPE=UTF is used by the UTF-8 locale coercing
        # during interpreter startup (on macOS).
        import _locale

        self.assertEqual(locale._parse_localename('UTF-8'), (None, 'UTF-8'))

        if hasattr(_locale, '_getdefaultlocale'):
            orig_getlocale = _locale._getdefaultlocale
            del _locale._getdefaultlocale
        else:
            orig_getlocale = None

        try:
            with os_helper.EnvironmentVarGuard() as env:
                env.unset('LC_ALL', 'LC_CTYPE', 'LANG', 'LANGUAGE')
                env.set('LC_CTYPE', 'UTF-8')

                with check_warnings(('', DeprecationWarning)):
                    self.assertEqual(locale.getdefaultlocale(), (None, 'UTF-8'))
        finally:
            if orig_getlocale is not None:
                _locale._getdefaultlocale = orig_getlocale

    def test_getencoding(self):
        # Invoke getencoding to make sure it does not cause exceptions.
diff --git a/Misc/NEWS.d/next/Library/2025-05-17-09-09-00.gh-issue-134086.asfhs.rst b/Misc/NEWS.d/next/Library/2025-05-17-09-09-00.gh-issue-134086.asfhs.rst
 Remove deprecated :func:`!locale.getdefaultlocale`.
diff --git a/Modules/_localemodule.c b/Modules/_localemodule.c
 }
 #endif

 #if defined(MS_WINDOWS)

 /*[clinic input]
 _locale._getdefaultlocale

 [clinic start generated code]*/

 static PyObject *
 _locale__getdefaultlocale_impl(PyObject *module)
 /*[clinic end generated code: output=e6254088579534c2 input=003ea41acd17f7c7]*/
 {
    char encoding[20];
    char locale[100];

    PyOS_snprintf(encoding, sizeof(encoding), "cp%u", GetACP());

    if (GetLocaleInfoA(LOCALE_USER_DEFAULT,
                      LOCALE_SISO639LANGNAME,
                      locale, sizeof(locale))) {
        Py_ssize_t i = strlen(locale);
        locale[i++] = '_';
        if (GetLocaleInfoA(LOCALE_USER_DEFAULT,
                          LOCALE_SISO3166CTRYNAME,
                          locale+i, (int)(sizeof(locale)-i)))
            return Py_BuildValue("ss", locale, encoding);
    }

    /* If we end up here, this windows version didn't know about
       ISO639/ISO3166 names (it's probably Windows 95).  Return the
       Windows language identifier instead (a hexadecimal number) */

    locale[0] = '0';
    locale[1] = 'x';
    if (GetLocaleInfoA(LOCALE_USER_DEFAULT, LOCALE_IDEFAULTLANGUAGE,
                      locale+2, sizeof(locale)-2)) {
        return Py_BuildValue("ss", locale, encoding);
    }

    /* cannot determine the language code (very unlikely) */
    Py_INCREF(Py_None);
    return Py_BuildValue("Os", Py_None, encoding);
 }
 #endif

 #ifdef HAVE_LANGINFO_H
 #define LANGINFO(X, Y) {#X, X, Y}
 static struct langinfo_constant{
 #ifdef HAVE_WCSXFRM
    _LOCALE_STRXFRM_METHODDEF
 #endif
 #if defined(MS_WINDOWS)
    _LOCALE__GETDEFAULTLOCALE_METHODDEF
 #endif
 #ifdef HAVE_LANGINFO_H
    _LOCALE_NL_LANGINFO_METHODDEF
 #endif
diff --git a/Modules/clinic/_localemodule.c.h b/Modules/clinic/_localemodule.c.h
Original file line number	Diff line number	Diff line change
Expand Up		@@ -35,7 +35,7 @@ Pending removal in Python 3.15

		* :class:`locale`:

		* The :func:`~locale.getdefaultlocale` function
		* The :func:`!~locale.getdefaultlocale` function
		has been deprecated since Python 3.11.
		Its removal was originally planned for Python 3.13 (:gh:`90817`),
		but has been postponed to Python 3.15.
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -327,31 +327,6 @@ The :mod:`locale` module defines the following exception and functions:
		The function now temporarily sets the ``LC_CTYPE`` locale in some cases.


		.. function:: getdefaultlocale([envvars])

		Tries to determine the default locale settings and returns them as a tuple of
		the form ``(language code, encoding)``.

		According to POSIX, a program which has not called ``setlocale(LC_ALL, '')``
		runs using the portable ``'C'`` locale. Calling ``setlocale(LC_ALL, '')`` lets
		it use the default locale as defined by the :envvar:`LANG` variable. Since we
		do not want to interfere with the current locale setting we thus emulate the
		behavior in the way described above.

		To maintain compatibility with other platforms, not only the :envvar:`LANG`
		variable is tested, but a list of variables given as envvars parameter. The
		first found to be defined will be used. envvars defaults to the search
		path used in GNU gettext; it must always contain the variable name
		``'LANG'``. The GNU gettext search path contains ``'LC_ALL'``,
		``'LC_CTYPE'``, ``'LANG'`` and ``'LANGUAGE'``, in that order.

		Except for the code ``'C'``, the language code corresponds to :rfc:`1766`.
		language code and encoding may be ``None`` if their values cannot be
		determined.

		.. deprecated-removed:: 3.11 3.15


		.. function:: getlocale(category=LC_CTYPE)

		Returns the current setting for the given locale category as sequence containing
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -1113,8 +1113,7 @@ conflict.
		components running in the same process (such as the GNU ``readline``
		library), the updated setting is also seen in subprocesses (regardless of
		whether or not those processes are running a Python interpreter), as well as
		in operations that query the environment rather than the current C locale
		(such as Python's own :func:`locale.getdefaultlocale`).
		in operations that query the environment rather than the current C locale.

		Configuring one of these locales (either explicitly or via the above
		implicit locale coercion) automatically enables the ``surrogateescape``
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -1811,7 +1811,7 @@ Standard Library
		* :func:`!importlib.resources.read_text`
		* :func:`!importlib.resources.path`

		* The :func:`locale.getdefaultlocale` function is deprecated and will be
		* The :func:`!locale.getdefaultlocale` function is deprecated and will be
		removed in Python 3.15. Use :func:`locale.setlocale`,
		:func:`locale.getpreferredencoding(False) <locale.getpreferredencoding>` and
		:func:`locale.getlocale` functions instead.
Expand DownExpand Up		@@ -2080,7 +2080,7 @@ Porting notes for the C API are

		* :mod:`calendar`: The :class:`calendar.LocaleTextCalendar` and
		:class:`calendar.LocaleHTMLCalendar` classes now use
		:func:`locale.getlocale`, instead of using :func:`locale.getdefaultlocale`,
		:func:`locale.getlocale`, instead of using :func:`!locale.getdefaultlocale`,
		if no locale is specified.
		(Contributed by Victor Stinner in :issue:`46659`.)

Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -23,7 +23,7 @@

		# Yuck: LC_MESSAGES is non-standard: can't tell whether it exists before
		# trying the import. So __all__ is also fiddled at the end of the file.
		__all__ = ["getlocale", "getdefaultlocale", "getpreferredencoding", "Error",
		__all__ = ["getlocale", "getpreferredencoding", "Error",
		"setlocale", "localeconv", "strcoll", "strxfrm",
		"str", "atof", "atoi", "format_string", "currency",
		"normalize", "LC_CTYPE", "LC_COLLATE", "LC_TIME", "LC_MONETARY",
Expand DownExpand Up		@@ -521,69 +521,6 @@ def _build_localename(localetuple):
		raise TypeError('Locale must be None, a string, or an iterable of '
		'two strings -- language code, encoding.') from None

		def getdefaultlocale(envvars=('LC_ALL', 'LC_CTYPE', 'LANG', 'LANGUAGE')):

		""" Tries to determine the default locale settings and returns
		them as tuple (language code, encoding).

		According to POSIX, a program which has not called
		setlocale(LC_ALL, "") runs using the portable 'C' locale.
		Calling setlocale(LC_ALL, "") lets it use the default locale as
		defined by the LANG variable. Since we don't want to interfere
		with the current locale setting we thus emulate the behavior
		in the way described above.

		To maintain compatibility with other platforms, not only the
		LANG variable is tested, but a list of variables given as
		envvars parameter. The first found to be defined will be
		used. envvars defaults to the search path used in GNU gettext;
		it must always contain the variable name 'LANG'.

		Except for the code 'C', the language code corresponds to RFC
		1766. code and encoding can be None in case the values cannot
		be determined.

		"""

		import warnings
		warnings._deprecated(
		"locale.getdefaultlocale",
		"{name!r} is deprecated and slated for removal in Python {remove}. "
		"Use setlocale(), getencoding() and getlocale() instead.",
		remove=(3, 15))
		return _getdefaultlocale(envvars)


		def _getdefaultlocale(envvars=('LC_ALL', 'LC_CTYPE', 'LANG', 'LANGUAGE')):
		try:
		# check if it's supported by the _locale module
		import _locale
		code, encoding = _locale._getdefaultlocale()
		except (ImportError, AttributeError):
		pass
		else:
		# make sure the code/encoding values are valid
		if sys.platform == "win32" and code and code[:2] == "0x":
		# map windows language identifier to language name
		code = windows_locale.get(int(code, 0))
		# ...add other platform-specific processing here, if
		# necessary...
		return code, encoding

		# fall back on POSIX behaviour
		import os
		lookup = os.environ.get
		for variable in envvars:
		localename = lookup(variable,None)
		if localename:
		if variable == 'LANGUAGE':
		localename = localename.split(':')[0]
		break
		else:
		localename = 'C'
		return _parse_localename(localename)


		def getlocale(category=LC_CTYPE):

		""" Returns the current setting for the given locale category as
Expand DownExpand Up		@@ -1728,12 +1665,11 @@ def _init_categories(categories=categories):
		_init_categories()
		del categories['LC_ALL']

		print('Locale defaults as determined bygetdefaultlocale():')
		print('Locale defaults as determined bylocale.getlocale() and locale.getpreferredencoding():')
		print('-'*72)
		lang, enc = getdefaultlocale()
		print('Language: ', lang or '(undefined)')
		print('Encoding: ', enc or '(undefined)')
		print()
		lang, enc = getlocale()
		print(f'Language: {lang or "(undefined)"}')
		print(f'Encoding: {enc or getpreferredencoding(False) or "(undefined)"}\n')

		print('Locale settings on startup:')
		print('-'*72)
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -483,30 +483,6 @@ def test_japanese(self):


		class TestMiscellaneous(unittest.TestCase):
		def test_defaults_UTF8(self):
		# Issue #18378: on (at least) macOS setting LC_CTYPE to "UTF-8" is
		# valid. Furthermore LC_CTYPE=UTF is used by the UTF-8 locale coercing
		# during interpreter startup (on macOS).
		import _locale

		self.assertEqual(locale._parse_localename('UTF-8'), (None, 'UTF-8'))

		if hasattr(_locale, '_getdefaultlocale'):
		orig_getlocale = _locale._getdefaultlocale
		del _locale._getdefaultlocale
		else:
		orig_getlocale = None

		try:
		with os_helper.EnvironmentVarGuard() as env:
		env.unset('LC_ALL', 'LC_CTYPE', 'LANG', 'LANGUAGE')
		env.set('LC_CTYPE', 'UTF-8')

		with check_warnings(('', DeprecationWarning)):
		self.assertEqual(locale.getdefaultlocale(), (None, 'UTF-8'))
		finally:
		if orig_getlocale is not None:
		_locale._getdefaultlocale = orig_getlocale

		def test_getencoding(self):
		# Invoke getencoding to make sure it does not cause exceptions.
Expand Down
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Remove deprecated :func:`!locale.getdefaultlocale`.
Original file line number	Diff line number	Diff line change
Expand Up		@@ -444,50 +444,6 @@ _locale_strxfrm_impl(PyObject module, PyObject str)
		}
		#endif

		#if defined(MS_WINDOWS)

		/*[clinic input]
		_locale._getdefaultlocale

		[clinic start generated code]*/

		static PyObject *
		_locale__getdefaultlocale_impl(PyObject *module)
		/[clinic end generated code: output=e6254088579534c2 input=003ea41acd17f7c7]/
		{
		char encoding[20];
		char locale[100];

		PyOS_snprintf(encoding, sizeof(encoding), "cp%u", GetACP());

		if (GetLocaleInfoA(LOCALE_USER_DEFAULT,
		LOCALE_SISO639LANGNAME,
		locale, sizeof(locale))) {
		Py_ssize_t i = strlen(locale);
		locale[i++] = '_';
		if (GetLocaleInfoA(LOCALE_USER_DEFAULT,
		LOCALE_SISO3166CTRYNAME,
		locale+i, (int)(sizeof(locale)-i)))
		return Py_BuildValue("ss", locale, encoding);
		}

		/* If we end up here, this windows version didn't know about
		ISO639/ISO3166 names (it's probably Windows 95). Return the
		Windows language identifier instead (a hexadecimal number) */

		locale[0] = '0';
		locale[1] = 'x';
		if (GetLocaleInfoA(LOCALE_USER_DEFAULT, LOCALE_IDEFAULTLANGUAGE,
		locale+2, sizeof(locale)-2)) {
		return Py_BuildValue("ss", locale, encoding);
		}

		/* cannot determine the language code (very unlikely) */
		Py_INCREF(Py_None);
		return Py_BuildValue("Os", Py_None, encoding);
		}
		#endif

		#ifdef HAVE_LANGINFO_H
		#define LANGINFO(X, Y) {#X, X, Y}
		static struct langinfo_constant{
Expand DownExpand Up		@@ -899,9 +855,6 @@ static struct PyMethodDef PyLocale_Methods[] = {
		#ifdef HAVE_WCSXFRM
		_LOCALE_STRXFRM_METHODDEF
		#endif
		#if defined(MS_WINDOWS)
		_LOCALE__GETDEFAULTLOCALE_METHODDEF
		#endif
		#ifdef HAVE_LANGINFO_H
		_LOCALE_NL_LANGINFO_METHODDEF
		#endif
Expand Down