bpo-31900: Fix localeconv() encoding for LC_NUMERIC (#4174)

* Add _Py_GetLocaleconvNumeric() function: decode decimal_point and
  thousands_sep fields of localeconv() from the LC_NUMERIC encoding,
  rather than decoding from the LC_CTYPE encoding.
* Modify locale.localeconv() and "n" formatter of str.format() (for
  int, float and complex to use _Py_GetLocaleconvNumeric()
  internally.

1 files changed, 29 insertions, 8 deletions

diff --git a/Modules/_localemodule.c b/Modules/_localemodule.c
index 324b694b83..f9eeeb72dd 100644
--- a/Modules/_localemodule.c
+++ b/Modules/_localemodule.c
@@ -139,8 +139,9 @@ PyLocale_localeconv(PyObject* self)
     PyObject *x;
 
     result = PyDict_New();
-    if (!result)
+    if (!result) {
         return NULL;
+    }
 
     /* if LC_NUMERIC is different in the C library, use saved value */
     l = localeconv();
@@ -171,12 +172,6 @@ PyLocale_localeconv(PyObject* self)
         RESULT(#i, x); \
     } while (0)
 
-    /* Numeric information */
-    RESULT_STRING(decimal_point);
-    RESULT_STRING(thousands_sep);
-    x = copy_grouping(l->grouping);
-    RESULT("grouping", x);
-
     /* Monetary information */
     RESULT_STRING(int_curr_symbol);
     RESULT_STRING(currency_symbol);
@@ -195,10 +190,36 @@ PyLocale_localeconv(PyObject* self)
     RESULT_INT(n_sep_by_space);
     RESULT_INT(p_sign_posn);
     RESULT_INT(n_sign_posn);
+
+    /* Numeric information */
+    PyObject *decimal_point, *thousands_sep;
+    const char *grouping;
+    if (_Py_GetLocaleconvNumeric(&decimal_point,
+                                 &thousands_sep,
+                                 &grouping) < 0) {
+        goto failed;
+    }
+
+    if (PyDict_SetItemString(result, "decimal_point", decimal_point) < 0) {
+        Py_DECREF(decimal_point);
+        Py_DECREF(thousands_sep);
+        goto failed;
+    }
+    Py_DECREF(decimal_point);
+
+    if (PyDict_SetItemString(result, "thousands_sep", thousands_sep) < 0) {
+        Py_DECREF(thousands_sep);
+        goto failed;
+    }
+    Py_DECREF(thousands_sep);
+
+    x = copy_grouping(grouping);
+    RESULT("grouping", x);
+
     return result;
 
   failed:
-    Py_XDECREF(result);
+    Py_DECREF(result);
     return NULL;
 }