gh-124969: Make locale.nl_langinfo(locale.ALT_DIGITS) returning a string again (GH-125774)

This is a follow up of GH-124974. Only Glibc needed a fix.
Now the returned value is a string consisting of semicolon-separated
symbols on all Posix platforms.

Author: serhiy-storchaka

Doc/library/locale.rst

@@ -158,8 +158,7 @@ The :mod:`locale` module defines the following exception and functions:
 
 .. function:: nl_langinfo(option)
 
-   Return some locale-specific information as a string (or a tuple for
-   ``ALT_DIGITS``).  This function is not
+   Return some locale-specific information as a string.  This function is not
    available on all systems, and the set of possible options might also vary
    across platforms.  The possible argument values are numbers, for which
    symbolic constants are available in the locale module.
@@ -312,7 +311,9 @@ The :mod:`locale` module defines the following exception and functions:
 
    .. data:: ALT_DIGITS
 
-      Get a tuple of up to 100 strings used to represent the values 0 to 99.
+      Get a string consisting of up to 100 semicolon-separated symbols used
+      to represent the values 0 to 99 in a locale-specific way.
+      In most locales this is an empty string.
 
    The function temporarily sets the ``LC_CTYPE`` locale to the locale
    of the category that determines the requested value (``LC_TIME``,

Lib/test/test__locale.py

@@ -26,7 +26,10 @@
     'bs_BA', 'fr_LU', 'kl_GL', 'fa_IR', 'de_BE', 'sv_SE', 'it_CH', 'uk_UA',
     'eu_ES', 'vi_VN', 'af_ZA', 'nb_NO', 'en_DK', 'tg_TJ', 'ps_AF', 'en_US',
     'fr_FR.ISO8859-1', 'fr_FR.UTF-8', 'fr_FR.ISO8859-15@euro',
-    'ru_RU.KOI8-R', 'ko_KR.eucKR']
+    'ru_RU.KOI8-R', 'ko_KR.eucKR',
+    'ja_JP.UTF-8', 'lzh_TW.UTF-8', 'my_MM.UTF-8', 'or_IN.UTF-8', 'shn_MM.UTF-8',
+    'ar_AE.UTF-8', 'bn_IN.UTF-8', 'mr_IN.UTF-8', 'th_TH.TIS620',
+]
 
 def setUpModule():
     global candidate_locales
@@ -78,11 +81,13 @@ def accept(loc):
     'C': (0, {}),
     'en_US': (0, {}),
     'fa_IR': (100, {0: '\u06f0\u06f0', 10: '\u06f1\u06f0', 99: '\u06f9\u06f9'}),
-    'ja_JP': (100, {0: '\u3007', 10: '\u5341', 99: '\u4e5d\u5341\u4e5d'}),
+    'ja_JP': (100, {1: '\u4e00', 10: '\u5341', 99: '\u4e5d\u5341\u4e5d'}),
     'lzh_TW': (32, {0: '\u3007', 10: '\u5341', 31: '\u5345\u4e00'}),
     'my_MM': (100, {0: '\u1040\u1040', 10: '\u1041\u1040', 99: '\u1049\u1049'}),
     'or_IN': (100, {0: '\u0b66', 10: '\u0b67\u0b66', 99: '\u0b6f\u0b6f'}),
     'shn_MM': (100, {0: '\u1090\u1090', 10: '\u1091\u1090', 99: '\u1099\u1099'}),
+    'ar_AE': (100, {0: '\u0660', 10: '\u0661\u0660', 99: '\u0669\u0669'}),
+    'bn_IN': (100, {0: '\u09e6', 10: '\u09e7\u09e6', 99: '\u09ef\u09ef'}),
 }
 
 if sys.platform == 'win32':
@@ -199,21 +204,28 @@ def test_lc_numeric_basic(self):
     def test_alt_digits_nl_langinfo(self):
         # Test nl_langinfo(ALT_DIGITS)
         tested = False
-        for loc, (count, samples) in known_alt_digits.items():
+        for loc in candidate_locales:
             with self.subTest(locale=loc):
                 try:
                     setlocale(LC_TIME, loc)
                 except Error:
                     self.skipTest(f'no locale {loc!r}')
                     continue
+
                 with self.subTest(locale=loc):
                     alt_digits = nl_langinfo(locale.ALT_DIGITS)
-                    self.assertIsInstance(alt_digits, tuple)
-                    if count and not alt_digits and support.is_apple:
-                        self.skipTest(f'ALT_DIGITS is not set for locale {loc!r} on Apple platforms')
-                    self.assertEqual(len(alt_digits), count)
-                    for i in samples:
-                        self.assertEqual(alt_digits[i], samples[i])
+                    self.assertIsInstance(alt_digits, str)
+                    alt_digits = alt_digits.split(';') if alt_digits else []
+                    if alt_digits:
+                        self.assertGreaterEqual(len(alt_digits), 10, alt_digits)
+                    loc1 = loc.split('.', 1)[0]
+                    if loc1 in known_alt_digits:
+                        count, samples = known_alt_digits[loc1]
+                        if count and not alt_digits:
+                            self.skipTest(f'ALT_DIGITS is not set for locale {loc!r} on this platform')
+                        self.assertEqual(len(alt_digits), count, alt_digits)
+                        for i in samples:
+                            self.assertEqual(alt_digits[i], samples[i])
                     tested = True
         if not tested:
             self.skipTest('no suitable locales')

Misc/NEWS.d/next/Library/2024-10-21-12-06-55.gh-issue-124969.xiY8UP.rst

@@ -0,0 +1,2 @@
+``locale.nl_langinfo(locale.ALT_DIGITS)`` now returns a string again. The
+returned value consists of up to 100 semicolon-separated symbols.

Modules/_localemodule.c

@@ -667,28 +667,36 @@ _locale_nl_langinfo_impl(PyObject *module, int item)
                 return NULL;
             }
             PyObject *pyresult;
+#ifdef __GLIBC__
 #ifdef ALT_DIGITS
-            if (item == ALT_DIGITS) {
-                /* The result is a sequence of up to 100 NUL-separated strings. */
-                const char *s = result;
+            if (item == ALT_DIGITS && *result) {
+                /* According to the POSIX specification the result must be
+                 * a sequence of up to 100 semicolon-separated strings.
+                 * But in Glibc they are NUL-separated. */
+                Py_ssize_t i = 0;
                 int count = 0;
-                for (; count < 100 && *s; count++) {
-                    s += strlen(s) + 1;
+                for (; count < 100 && result[i]; count++) {
+                    i += strlen(result + i) + 1;
                 }
-                pyresult = PyTuple_New(count);
-                if (pyresult != NULL) {
-                    for (int i = 0; i < count; i++) {
-                        PyObject *unicode = PyUnicode_DecodeLocale(result, NULL);
-                        if (unicode == NULL) {
-                            Py_CLEAR(pyresult);
-                            break;
-                        }
-                        PyTuple_SET_ITEM(pyresult, i, unicode);
-                        result += strlen(result) + 1;
+                char *buf = PyMem_Malloc(i);
+                if (buf == NULL) {
+                    PyErr_NoMemory();
+                    pyresult = NULL;
+                }
+                else {
+                    memcpy(buf, result, i);
+                    /* Replace all NULs with semicolons. */
+                    i = 0;
+                    while (--count) {
+                        i += strlen(buf + i);
+                        buf[i++] = ';';
                     }
+                    pyresult = PyUnicode_DecodeLocale(buf, NULL);
+                    PyMem_Free(buf);
                 }
             }
             else
+#endif
 #endif
             {
                 pyresult = PyUnicode_DecodeLocale(result, NULL);