Revert "bpo-34589: Add -X coerce_c_locale command line option (GH-9378)" (GH-9430)

* Revert "bpo-34589: Add -X coerce_c_locale command line option (GH-9378)"

This reverts commit dbdee00.

* Revert "bpo-34589: C locale coercion off by default (GH-9073)"

This reverts commit 7a0791b.

* Revert "bpo-34589: Make _PyCoreConfig.coerce_c_locale private (GH-9371)"

This reverts commit 188ebfa.

Author: vstinner

Doc/using/cmdline.rst

@@ -438,22 +438,13 @@ Miscellaneous options
      * Set the :attr:`~sys.flags.dev_mode` attribute of :attr:`sys.flags` to
        ``True``
 
-   * ``-X utf8`` enables UTF-8 mode (:pep:`540`) for operating system interfaces, overriding
+   * ``-X utf8`` enables UTF-8 mode for operating system interfaces, overriding
      the default locale-aware mode. ``-X utf8=0`` explicitly disables UTF-8
      mode (even when it would otherwise activate automatically).
      See :envvar:`PYTHONUTF8` for more details.
    * ``-X pycache_prefix=PATH`` enables writing ``.pyc`` files to a parallel
      tree rooted at the given directory instead of to the code tree. See also
      :envvar:`PYTHONPYCACHEPREFIX`.
-   * ``-X coerce_c_locale`` or ``-X coerce_c_locale=1`` tries to coerce the C
-     locale (:pep:`538`).
-     ``-X coerce_c_locale=0`` skips coercing the legacy ASCII-based C and POSIX
-     locales to a more capable UTF-8 based alternative.
-     ``-X coerce_c_locale=warn`` will cause Python to emit warning messages on
-     ``stderr`` if either the locale coercion activates, or else if a locale
-     that *would* have triggered coercion is still active when the Python
-     runtime is initialized.
-     See :envvar:`PYTHONCOERCECLOCALE` for more details.
 
    It also allows passing arbitrary values and retrieving them through the
    :data:`sys._xoptions` dictionary.
@@ -473,9 +464,6 @@ Miscellaneous options
    .. versionadded:: 3.7
       The ``-X importtime``, ``-X dev`` and ``-X utf8`` options.
 
-   .. versionadded:: 3.7.1
-      The ``-X coerce_c_locale`` option.
-
    .. versionadded:: 3.8
       The ``-X pycache_prefix`` option.
 
@@ -862,8 +850,6 @@ conflict.
    order to force the interpreter to use ``ASCII`` instead of ``UTF-8`` for
    system interfaces.
 
-   Also available as the :option:`-X` ``coerce_c_locale`` option.
-
    Availability: \*nix
 
    .. versionadded:: 3.7

Doc/whatsnew/3.7.rst

@@ -2494,10 +2494,3 @@ versions, it respected an ill-defined subset of those environment variables,
 while in Python 3.7.0 it didn't read any of them due to :issue:`34247`). If
 this behavior is unwanted, set :c:data:`Py_IgnoreEnvironmentFlag` to 1 before
 calling :c:func:`Py_Initialize`.
-
-:c:func:`Py_Initialize` and :c:func:`Py_Main` cannot enable the C locale
-coercion (:pep:`538`) anymore: it is always disabled. It can now only be
-enabled by the Python program ("python3).
-
-New :option:`-X` ``coerce_c_locale`` command line option to control C locale
-coercion (:pep:`538`).

Include/coreconfig.h

@@ -63,6 +63,8 @@ typedef struct {
     int show_alloc_count;   /* -X showalloccount */
     int dump_refs;          /* PYTHONDUMPREFS */
     int malloc_stats;       /* PYTHONMALLOCSTATS */
+    int coerce_c_locale;    /* PYTHONCOERCECLOCALE, -1 means unknown */
+    int coerce_c_locale_warn; /* PYTHONCOERCECLOCALE=warn */
 
     /* Python filesystem encoding and error handler:
        sys.getfilesystemencoding() and sys.getfilesystemencodeerrors().
@@ -295,30 +297,6 @@ typedef struct {
        If set to -1 (default), inherit Py_FrozenFlag value. */
     int _frozen;
 
-    /* C locale coercion (PEP 538).
-
-       The option is enabled by the PYTHONCOERCECLOCALE environment
-       variable. The option is also enabled if the LC_CTYPE locale is "C"
-       and a target locale (ex: "C.UTF-8") is supported by the platform.
-
-       Py_Initialize() and Py_Main() must not enable C locale coercion: it is
-       always disabled. The option can only be enabled by the Python program
-       ("python3).
-
-       See also the _coerce_c_locale_warn option. */
-    int _coerce_c_locale;
-
-    /* C locale coercion warning (PEP 538).
-
-       Enabled by the PYTHONCOERCECLOCALE=warn environment variable.
-
-       Py_Initialize() and Py_Main() must not enable C locale coercion warning:
-       it is always disabled. The warning can only be enabled by the Python
-       program ("python3).
-
-       See also the _coerce_c_locale option. */
-    int _coerce_c_locale_warn;
-
 } _PyCoreConfig;
 
 #ifdef MS_WINDOWS
@@ -336,8 +314,7 @@ typedef struct {
         .use_hash_seed = -1, \
         .faulthandler = -1, \
         .tracemalloc = -1, \
-        ._coerce_c_locale = 0, \
-        ._coerce_c_locale_warn = 0, \
+        .coerce_c_locale = -1, \
         .utf8_mode = -1, \
         .argc = -1, \
         .nmodule_search_path = -1, \

Include/pylifecycle.h

@@ -83,11 +83,7 @@ PyAPI_FUNC(int) Py_FdIsInteractive(FILE *, const char *);
 /* Bootstrap __main__ (defined in Modules/main.c) */
 PyAPI_FUNC(int) Py_Main(int argc, wchar_t **argv);
 #ifdef Py_BUILD_CORE
-#  ifdef MS_WINDOWS
-PyAPI_FUNC(int) _Py_WindowsMain(int argc, wchar_t **argv);
-#  else
 PyAPI_FUNC(int) _Py_UnixMain(int argc, char **argv);
-#  endif
 #endif
 
 /* In getpath.c */

Lib/test/test_c_locale_coercion.py

@@ -139,7 +139,7 @@ def _handle_output_variations(data):
         return data
 
     @classmethod
-    def get_child_details(cls, env_vars, xoption=None):
+    def get_child_details(cls, env_vars):
         """Retrieves fsencoding and standard stream details from a child process
 
         Returns (encoding_details, stderr_lines):
@@ -150,11 +150,10 @@ def get_child_details(cls, env_vars, xoption=None):
         The child is run in isolated mode if the current interpreter supports
         that.
         """
-        args = []
-        if xoption:
-            args.extend(("-X", f"coerce_c_locale={xoption}"))
-        args.extend(("-X", "utf8=0", "-c", cls.CHILD_PROCESS_SCRIPT))
-        result, py_cmd = run_python_until_end(*args, **env_vars)
+        result, py_cmd = run_python_until_end(
+            "-X", "utf8=0", "-c", cls.CHILD_PROCESS_SCRIPT,
+            **env_vars
+        )
         if not result.rc == 0:
             result.fail(py_cmd)
         # All subprocess outputs in this test case should be pure ASCII
@@ -213,16 +212,15 @@ def _check_child_encoding_details(self,
                                       expected_fs_encoding,
                                       expected_stream_encoding,
                                       expected_warnings,
-                                      coercion_expected,
-                                      xoption=None):
+                                      coercion_expected):
         """Check the C locale handling for the given process environment
 
         Parameters:
             expected_fs_encoding: expected sys.getfilesystemencoding() result
             expected_stream_encoding: expected encoding for standard streams
             expected_warning: stderr output to expect (if any)
         """
-        result = EncodingDetails.get_child_details(env_vars, xoption)
+        result = EncodingDetails.get_child_details(env_vars)
         encoding_details, stderr_lines = result
         expected_details = EncodingDetails.get_expected_details(
             coercion_expected,
@@ -292,7 +290,6 @@ def _check_c_locale_coercion(self,
                                  coerce_c_locale,
                                  expected_warnings=None,
                                  coercion_expected=True,
-                                 use_xoption=False,
                                  **extra_vars):
         """Check the C locale handling for various configurations
 
@@ -322,12 +319,8 @@ def _check_c_locale_coercion(self,
             "PYTHONCOERCECLOCALE": "",
         }
         base_var_dict.update(extra_vars)
-        xoption = None
         if coerce_c_locale is not None:
-            if use_xoption:
-                xoption = coerce_c_locale
-            else:
-                base_var_dict["PYTHONCOERCECLOCALE"] = coerce_c_locale
+            base_var_dict["PYTHONCOERCECLOCALE"] = coerce_c_locale
 
         # Check behaviour for the default locale
         with self.subTest(default_locale=True,
@@ -349,8 +342,7 @@ def _check_c_locale_coercion(self,
                                                fs_encoding,
                                                stream_encoding,
                                                _expected_warnings,
-                                               _coercion_expected,
-                                               xoption=xoption)
+                                               _coercion_expected)
 
         # Check behaviour for explicitly configured locales
         for locale_to_set in EXPECTED_C_LOCALE_EQUIVALENTS:
@@ -365,8 +357,7 @@ def _check_c_locale_coercion(self,
                                                        fs_encoding,
                                                        stream_encoding,
                                                        expected_warnings,
-                                                       coercion_expected,
-                                                       xoption=xoption)
+                                                       coercion_expected)
 
     def test_PYTHONCOERCECLOCALE_not_set(self):
         # This should coerce to the first available target locale by default
@@ -413,32 +404,6 @@ def test_LC_ALL_set_to_C(self):
                                       expected_warnings=[LEGACY_LOCALE_WARNING],
                                       coercion_expected=False)
 
-    def test_xoption_set_to_1(self):
-        self._check_c_locale_coercion("utf-8", "utf-8", coerce_c_locale="1",
-                                      use_xoption=True)
-
-    def test_xoption_set_to_zero(self):
-        # The setting "0" should result in the locale coercion being disabled
-        self._check_c_locale_coercion(EXPECTED_C_LOCALE_FS_ENCODING,
-                                      EXPECTED_C_LOCALE_STREAM_ENCODING,
-                                      coerce_c_locale="0",
-                                      coercion_expected=False,
-                                      use_xoption=True)
-        # Setting LC_ALL=C shouldn't make any difference to the behaviour
-        self._check_c_locale_coercion(EXPECTED_C_LOCALE_FS_ENCODING,
-                                      EXPECTED_C_LOCALE_STREAM_ENCODING,
-                                      coerce_c_locale="0",
-                                      LC_ALL="C",
-                                      coercion_expected=False,
-                                      use_xoption=True)
-
-    def test_xoption_set_to_warn(self):
-        # -X coerce_c_locale=warn enables runtime warnings for legacy locales
-        self._check_c_locale_coercion("utf-8", "utf-8",
-                                      coerce_c_locale="warn",
-                                      expected_warnings=[CLI_COERCION_WARNING],
-                                      use_xoption=True)
-
 def test_main():
     test.support.run_unittest(
         LocaleConfigurationTests,

Lib/test/test_cmd_line.py

@@ -159,16 +159,13 @@ def test_undecodable_code(self):
         env = os.environ.copy()
         # Use C locale to get ascii for the locale encoding
         env['LC_ALL'] = 'C'
+        env['PYTHONCOERCECLOCALE'] = '0'
         code = (
             b'import locale; '
             b'print(ascii("' + undecodable + b'"), '
                 b'locale.getpreferredencoding())')
         p = subprocess.Popen(
-            [sys.executable,
-             # Disable C locale coercion and UTF-8 Mode to not use UTF-8
-             "-X", "coerce_c_locale=0",
-             "-X", "utf8=0",
-             "-c", code],
+            [sys.executable, "-c", code],
             stdout=subprocess.PIPE, stderr=subprocess.STDOUT,
             env=env)
         stdout, stderr = p.communicate()

Lib/test/test_embed.py

@@ -277,6 +277,8 @@ class InitConfigTests(EmbeddingTestsMixin, unittest.TestCase):
         'filesystem_errors': None,
 
         'utf8_mode': 0,
+        'coerce_c_locale': 0,
+        'coerce_c_locale_warn': 0,
 
         'pycache_prefix': NULL_STR,
         'program_name': './_testembed',
@@ -304,8 +306,6 @@ class InitConfigTests(EmbeddingTestsMixin, unittest.TestCase):
         '_install_importlib': 1,
         '_check_hash_pycs_mode': 'default',
         '_frozen': 0,
-        '_coerce_c_locale': 0,
-        '_coerce_c_locale_warn': 0,
     }
 
     def get_stdio_encoding(self, env):
@@ -324,6 +324,10 @@ def get_filesystem_encoding(self, isolated, env):
                 'print(sys.getfilesystemencoding(), '
                 'sys.getfilesystemencodeerrors())')
         args = (sys.executable, '-c', code)
+        env = dict(env)
+        if not isolated:
+            env['PYTHONCOERCECLOCALE'] = '0'
+            env['PYTHONUTF8'] = '0'
         proc = subprocess.run(args, text=True, env=env,
                               stdout=subprocess.PIPE,
                               stderr=subprocess.PIPE)

Lib/test/test_sys.py

@@ -656,8 +656,9 @@ def test_getfilesystemencoding(self):
 
     def c_locale_get_error_handler(self, locale, isolated=False, encoding=None):
         # Force the POSIX locale
-        env = dict(os.environ)
+        env = os.environ.copy()
         env["LC_ALL"] = locale
+        env["PYTHONCOERCECLOCALE"] = "0"
         code = '\n'.join((
             'import sys',
             'def dump(name):',
@@ -667,10 +668,7 @@ def c_locale_get_error_handler(self, locale, isolated=False, encoding=None):
             'dump("stdout")',
             'dump("stderr")',
         ))
-        args = [sys.executable,
-                "-X", "utf8=0",
-                "-X", "coerce_c_locale=0",
-                "-c", code]
+        args = [sys.executable, "-X", "utf8=0", "-c", code]
         if isolated:
             args.append("-I")
         if encoding is not None:

Lib/test/test_utf8_mode.py

@@ -27,8 +27,6 @@ def posix_locale(self):
         return (loc in POSIX_LOCALES)
 
     def get_output(self, *args, failure=False, **kw):
-        # Always disable the C locale coercion (PEP 538)
-        args = ('-X', 'coerce_c_locale=0', *args)
         kw = dict(self.DEFAULT_ENV, **kw)
         if failure:
             out = assert_python_failure(*args, **kw)
@@ -118,6 +116,7 @@ def test_filesystemencoding(self):
             # PYTHONLEGACYWINDOWSFSENCODING disables the UTF-8 mode
             # and has the priority over -X utf8 and PYTHONUTF8
             out = self.get_output('-X', 'utf8', '-c', code,
+                                  PYTHONUTF8='strict',
                                   PYTHONLEGACYWINDOWSFSENCODING='1')
             self.assertEqual(out, 'mbcs/replace')