Index: Objects/unicodeobject.c
===================================================================
--- Objects/unicodeobject.c	(révision 81871)
+++ Objects/unicodeobject.c	(copie de travail)
@@ -1478,11 +1478,18 @@

 PyObject *PyUnicode_EncodeFSDefault(PyObject *unicode)
 {
-    if (Py_FileSystemDefaultEncoding)
+    if (Py_FileSystemDefaultEncoding) {
+#if defined(MS_WINDOWS) && defined(HAVE_USABLE_WCHAR_T)
+        if (strcmp(Py_FileSystemDefaultEncoding, "mbcs") == 0)
+            /* mbcs in strict mode */
+            return PyUnicode_EncodeMBCS(PyUnicode_AS_UNICODE(unicode),
+                                        PyUnicode_GET_SIZE(unicode),
+                                        NULL);
+#endif
         return PyUnicode_AsEncodedString(unicode,
                                          Py_FileSystemDefaultEncoding,
                                          "surrogateescape");
-    else
+    } else
         return PyUnicode_EncodeUTF8(PyUnicode_AS_UNICODE(unicode),
                                      PyUnicode_GET_SIZE(unicode),
                                      "surrogateescape");
@@ -1639,7 +1646,7 @@
     if (Py_FileSystemDefaultEncoding) {
 #if defined(MS_WINDOWS) && defined(HAVE_USABLE_WCHAR_T)
         if (strcmp(Py_FileSystemDefaultEncoding, "mbcs") == 0) {
-            return PyUnicode_DecodeMBCS(s, size, "surrogateescape");
+            return PyUnicode_DecodeMBCS(s, size, NULL);
         }
 #elif defined(__APPLE__)
         if (strcmp(Py_FileSystemDefaultEncoding, "utf-8") == 0) {
Index: Doc/library/os.rst
===================================================================
--- Doc/library/os.rst	(révision 81870)
+++ Doc/library/os.rst	(copie de travail)
@@ -159,11 +159,11 @@
 .. function:: fsencode(value)

    Encode *value* to bytes for use in the file system, environment variables or
-   the command line. Uses :func:`sys.getfilesystemencoding` and
-   ``'surrogateescape'`` error handler for strings and returns bytes unchanged.
+   the command line. Use :func:`sys.getfilesystemencoding` and
+   ``'surrogateescape'`` error handler for strings and return bytes unchanged.
+   On Windows, use ``'strict'`` error handler for strings if the file system
+   encoding is ``'mbcs'`` (which is the default encoding).

-   Availability: Unix.
-
    .. versionadded:: 3.2


Index: Lib/os.py
===================================================================
--- Lib/os.py	(révision 81870)
+++ Lib/os.py	(copie de travail)
@@ -533,16 +533,19 @@
         return environb.get(key, default)
     __all__.append("getenvb")

-if name != 'nt':
-    def fsencode(value):
-        """Encode value for use in the file system, environment variables
-        or the command line."""
-        if isinstance(value, bytes):
-            return value
-        elif isinstance(value, str):
-            return value.encode(sys.getfilesystemencoding(), 'surrogateescape')
+def fsencode(value):
+    """Encode value for use in the file system, environment variables
+    or the command line."""
+    if isinstance(value, bytes):
+        return value
+    elif isinstance(value, str):
+        encoding = sys.getfilesystemencoding()
+        if encoding == 'mbcs':
+            return value.encode(encoding)
         else:
-            raise TypeError("expect bytes or str, not %s" % type(value).__name__)
+            return value.encode(encoding, 'surrogateescape')
+    else:
+        raise TypeError("expect bytes or str, not %s" % type(value).__name__)

 def _exists(name):
     return name in globals()
Index: Lib/test/test_ssl.py
===================================================================
--- Lib/test/test_ssl.py	(révision 81870)
+++ Lib/test/test_ssl.py	(copie de travail)
@@ -33,16 +33,15 @@
 HOST = support.HOST

 data_file = lambda name: os.path.join(os.path.dirname(__file__), name)
-fsencode = lambda name: name.encode(sys.getfilesystemencoding(), "surrogateescape")

 CERTFILE = data_file("keycert.pem")
-BYTES_CERTFILE = fsencode(CERTFILE)
+BYTES_CERTFILE = os.fsencode(CERTFILE)
 ONLYCERT = data_file("ssl_cert.pem")
 ONLYKEY = data_file("ssl_key.pem")
-BYTES_ONLYCERT = fsencode(ONLYCERT)
-BYTES_ONLYKEY = fsencode(ONLYKEY)
+BYTES_ONLYCERT = os.fsencode(ONLYCERT)
+BYTES_ONLYKEY = os.fsencode(ONLYKEY)
 CAPATH = data_file("capath")
-BYTES_CAPATH = fsencode(CAPATH)
+BYTES_CAPATH = os.fsencode(CAPATH)

 SVN_PYTHON_ORG_ROOT_CERT = data_file("https_svn_python_org_root.pem")