pythongh-104783: Remove locale.getdefaultlocale()

Remove locale.getdefaultlocale() and locale.resetlocale() functions.

locale.getencoding() now uses sys.getfilesystemencoding() if
_locale.getencoding() is missing.

Doc/library/locale.rst

@@ -281,31 +281,6 @@ The :mod:`locale` module defines the following exception and functions:
       0 to 99.
 
 
-.. 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 3.13
-
-
 .. function:: getlocale(category=LC_CTYPE)
 
    Returns the current setting for the given locale category as sequence containing
@@ -370,16 +345,6 @@ The :mod:`locale` module defines the following exception and functions:
    encoding for the locale code just like :func:`setlocale`.
 
 
-.. function:: resetlocale(category=LC_ALL)
-
-   Sets the locale for *category* to the default setting.
-
-   The default setting is determined by calling :func:`getdefaultlocale`.
-   *category* defaults to :const:`LC_ALL`.
-
-   .. deprecated-removed:: 3.11 3.13
-
-
 .. function:: strcoll(string1, string2)
 
    Compares two strings according to the current :const:`LC_COLLATE` setting. As

Doc/whatsnew/3.13.rst

@@ -102,6 +102,14 @@ Deprecated
 Removed
 =======
 
+* Remove two :mod:`locale` functions deprecated in Python 3.11:
+
+  * ``getdefaultlocale()``: use :func:`locale.setlocale`,
+    :func:`locale.getpreferredencoding(False) <locale.getpreferredencoding>`
+    and :func:`locale.getlocale` functions instead.
+  * ``resetlocale()``: use ``locale.setlocale(locale.LC_ALL, "")`` instead.
+
+  (Contributed by Victor Stinner in :gh:`104783`.)
 
 
 Porting to Python 3.13

Lib/locale.py

@@ -24,8 +24,8 @@
 
 # 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",
-           "setlocale", "resetlocale", "localeconv", "strcoll", "strxfrm",
+__all__ = ["getlocale", "getpreferredencoding", "Error",
+           "setlocale", "localeconv", "strcoll", "strxfrm",
            "str", "atof", "atoi", "format_string", "currency",
            "normalize", "LC_CTYPE", "LC_COLLATE", "LC_TIME", "LC_MONETARY",
            "LC_NUMERIC", "LC_ALL", "CHAR_MAX", "getencoding"]
@@ -516,67 +516,6 @@ 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.warn(
-        "Use setlocale(), getencoding() and getlocale() instead",
-        DeprecationWarning, stacklevel=2
-    )
-    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
@@ -612,40 +551,15 @@ def setlocale(category, locale=None):
         locale = normalize(_build_localename(locale))
     return _setlocale(category, locale)
 
-def resetlocale(category=LC_ALL):
-
-    """ Sets the locale for category to the default setting.
-
-        The default setting is determined by calling
-        getdefaultlocale(). category defaults to LC_ALL.
-
-    """
-    import warnings
-    warnings.warn(
-        'Use locale.setlocale(locale.LC_ALL, "") instead',
-        DeprecationWarning, stacklevel=2
-    )
-
-    with warnings.catch_warnings():
-        warnings.simplefilter('ignore', category=DeprecationWarning)
-        loc = getdefaultlocale()
-
-    _setlocale(category, _build_localename(loc))
-
 
 try:
     from _locale import getencoding
 except ImportError:
+    # When _locale.getencoding() is missing, use the Python filesystem
+    # encoding.
+    _encoding = sys.getfilesystemencoding()
     def getencoding():
-        if hasattr(sys, 'getandroidapilevel'):
-            # On Android langinfo.h and CODESET are missing, and UTF-8 is
-            # always used in mbstowcs() and wcstombs().
-            return 'utf-8'
-        encoding = _getdefaultlocale()[1]
-        if encoding is None:
-            # LANG not set, default to UTF-8
-            encoding = 'utf-8'
-        return encoding
+        return _encoding
 
 try:
     CODESET
@@ -1713,13 +1627,6 @@ def _init_categories(categories=categories):
     _init_categories()
     del categories['LC_ALL']
 
-    print('Locale defaults as determined by getdefaultlocale():')
-    print('-'*72)
-    lang, enc = getdefaultlocale()
-    print('Language: ', lang or '(undefined)')
-    print('Encoding: ', enc or '(undefined)')
-    print()
-
     print('Locale settings on startup:')
     print('-'*72)
     for name,category in categories.items():
@@ -1729,17 +1636,6 @@ def _init_categories(categories=categories):
         print('   Encoding: ', enc or '(undefined)')
         print()
 
-    print()
-    print('Locale settings after calling resetlocale():')
-    print('-'*72)
-    resetlocale()
-    for name,category in categories.items():
-        print(name, '...')
-        lang, enc = getlocale(category)
-        print('   Language: ', lang or '(undefined)')
-        print('   Encoding: ', enc or '(undefined)')
-        print()
-
     try:
         setlocale(LC_ALL, "")
     except:

Lib/test/test_locale.py

@@ -478,43 +478,9 @@ 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
-        import os
-
+    def test_parse_localename(self):
         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
-
-        orig_env = {}
-        try:
-            for key in ('LC_ALL', 'LC_CTYPE', 'LANG', 'LANGUAGE'):
-                if key in os.environ:
-                    orig_env[key] = os.environ[key]
-                    del os.environ[key]
-
-            os.environ['LC_CTYPE'] = 'UTF-8'
-
-            with check_warnings(('', DeprecationWarning)):
-                self.assertEqual(locale.getdefaultlocale(), (None, 'UTF-8'))
-
-        finally:
-            for k in orig_env:
-                os.environ[k] = orig_env[k]
-
-            if 'LC_CTYPE' not in orig_env:
-                del os.environ['LC_CTYPE']
-
-            if orig_getlocale is not None:
-                _locale._getdefaultlocale = orig_getlocale
-
     def test_getencoding(self):
         # Invoke getencoding to make sure it does not cause exceptions.
         enc = locale.getencoding()

Misc/NEWS.d/next/Library/2023-05-23-04-01-27.gh-issue-104783.QyhIoq.rst

@@ -0,0 +1,2 @@
+Remove two :mod:`locale` functions deprecated in Python 3.11:
+``getdefaultlocale()`` and ``resetlocale()``. Patch by Victor Stinner.