Index: Python/pythonrun.c
===================================================================
--- Python/pythonrun.c	(révision 80924)
+++ Python/pythonrun.c	(copie de travail)
@@ -57,6 +57,7 @@
 
 /* Forward */
 static void initmain(void);
+static void initfsencoding(void);
 static void initsite(void);
 static int initstdio(void);
 static void flush_io(void);
@@ -171,9 +172,6 @@
 	PyThreadState *tstate;
 	PyObject *bimod, *sysmod, *pstderr;
 	char *p;
-#if defined(HAVE_LANGINFO_H) && defined(CODESET)
-	char *codeset;
-#endif
 	extern void _Py_ReadyTypes(void);
 
 	if (initialized)
@@ -264,22 +262,8 @@
 
 	_PyImportHooks_Init();
 
-#if defined(HAVE_LANGINFO_H) && defined(CODESET)
-	/* On Unix, set the file system encoding according to the
-	   user's preference, if the CODESET names a well-known
-	   Python codec, and Py_FileSystemDefaultEncoding isn't
-	   initialized by other means. Also set the encoding of
-	   stdin and stdout if these are terminals.  */
+	initfsencoding();
 
-	codeset = get_codeset();
-	if (codeset) {
-		if (!Py_FileSystemDefaultEncoding)
-			Py_FileSystemDefaultEncoding = codeset;
-		else
-			free(codeset);
-	}
-#endif
-
 	if (install_sigs)
 		initsigs(); /* Signal handling stuff, including initintr() */
 		
@@ -498,7 +482,8 @@
 	/* reset file system default encoding */
 	if (!Py_HasFileSystemDefaultEncoding) {
 		free((char*)Py_FileSystemDefaultEncoding);
-		Py_FileSystemDefaultEncoding = NULL;
+		Py_FileSystemDefaultEncoding = "ascii";
+		Py_HasFileSystemDefaultEncoding = 1;
 	}
 
 	/* XXX Still allocated:
@@ -707,6 +692,39 @@
 	}
 }
 
+static void
+initfsencoding(void)
+{
+	PyObject *codec;
+#if defined(HAVE_LANGINFO_H) && defined(CODESET)
+	char *codeset;
+
+	/* On Unix, set the file system encoding according to the
+	   user's preference, if the CODESET names a well-known
+	   Python codec, and Py_FileSystemDefaultEncoding isn't
+	   initialized by other means. Also set the encoding of
+	   stdin and stdout if these are terminals.  */
+	codeset = get_codeset();
+	if (codeset == NULL) {
+		fprintf(stderr,
+			"Unable to get the locale encoding: "
+			"fallback to ascii\n");
+		Py_FileSystemDefaultEncoding = "ascii";
+		Py_HasFileSystemDefaultEncoding = 1;
+	} else {
+		Py_FileSystemDefaultEncoding = codeset;
+	}
+#endif
+
+	codec = _PyCodec_Lookup(Py_FileSystemDefaultEncoding);
+	if (!codec) {
+		Py_FatalError(
+		    "Py_Initialize: unable to load the file system codec");
+	} else {
+		Py_DECREF(codec);
+	}
+}
+
 /* Import the site module (not into __main__ though) */
 
 static void
Index: Python/bltinmodule.c
===================================================================
--- Python/bltinmodule.c	(révision 80924)
+++ Python/bltinmodule.c	(copie de travail)
@@ -9,6 +9,10 @@
 
 #include <ctype.h>
 
+#ifdef HAVE_LANGINFO_H
+#include <langinfo.h>   /* CODESET */
+#endif
+
 /* The default encoding used by the platform file system APIs
    Can remain NULL for all platforms that don't have such a concept
 
@@ -21,9 +25,12 @@
 #elif defined(__APPLE__)
 const char *Py_FileSystemDefaultEncoding = "utf-8";
 int Py_HasFileSystemDefaultEncoding = 1;
+#elif defined(HAVE_LANGINFO_H) && defined(CODESET)
+const char *Py_FileSystemDefaultEncoding = NULL; /* set by initfsencoding() */
+int Py_HasFileSystemDefaultEncoding = 0;
 #else
-const char *Py_FileSystemDefaultEncoding = NULL; /* use default */
-int Py_HasFileSystemDefaultEncoding = 0;
+const char *Py_FileSystemDefaultEncoding = "ascii";
+int Py_HasFileSystemDefaultEncoding = 1;
 #endif
 
 int
Index: Objects/unicodeobject.c
===================================================================
--- Objects/unicodeobject.c	(révision 80924)
+++ Objects/unicodeobject.c	(copie de travail)
@@ -1612,7 +1612,7 @@
                                 "surrogateescape");
     }
     else {
-        return PyUnicode_DecodeUTF8(s, size, "surrogateescape");
+        return PyUnicode_DecodeASCII(s, size, "surrogateescape");
     }
 }
 
Index: Misc/NEWS
===================================================================
--- Misc/NEWS	(révision 80924)
+++ Misc/NEWS	(copie de travail)
@@ -12,6 +12,10 @@
 Core and Builtins
 -----------------
 
+- Issue #8610: Load file system codec at startup, and display a fatal error on
+  failure. Set the file system encoding to ascii if getting the locale encoding
+  failed, or if nl_langinfo(CODESET) function is missing.
+
 - PyFile_FromFd() uses PyUnicode_DecodeFSDefault() instead of
   PyUnicode_FromString() to support surrogates in the filename and use the
   right encoding
Index: Doc/library/sys.rst
===================================================================
--- Doc/library/sys.rst	(révision 80924)
+++ Doc/library/sys.rst	(copie de travail)
@@ -298,15 +298,13 @@
 
 .. function:: getfilesystemencoding()
 
-   Return the name of the encoding used to convert Unicode filenames into system
-   file names, or ``None`` if the system default encoding is used. The result value
-   depends on the operating system:
+   Return the name of the encoding used to convert Unicode filenames into
+   system file names. The result value depends on the operating system:
 
    * On Mac OS X, the encoding is ``'utf-8'``.
 
    * On Unix, the encoding is the user's preference according to the result of
-     nl_langinfo(CODESET), or ``None`` if the ``nl_langinfo(CODESET)``
-     failed.
+     nl_langinfo(CODESET), or ``ascii`` if ``nl_langinfo(CODESET)`` failed.
 
    * On Windows NT+, file names are Unicode natively, so no conversion is
      performed. :func:`getfilesystemencoding` still returns ``'mbcs'``, as
@@ -316,7 +314,11 @@
 
    * On Windows 9x, the encoding is ``'mbcs'``.
 
+   .. versionchanged:: 3.2
+      On Unix, use ``ascii`` instead of ``None`` if ``nl_langinfo(CODESET)``
+      failed. :func:`getfilesystemencoding` result cannot be ``None``.
 
+
 .. function:: getrefcount(object)
 
    Return the reference count of the *object*.  The count returned is generally one