Index: Lib/genericpath.py
===================================================================
--- Lib/genericpath.py	(révision 80417)
+++ Lib/genericpath.py	(copie de travail)
@@ -104,3 +104,12 @@
             filenameIndex += 1
 
     return p, p[:0]
+
+def fs_decode(path):
+    """Decode a path from the file system encoding"""
+    return path
+
+def fs_encode(path):
+    """Encode a path to the file system encoding"""
+    return path
+
Index: Lib/posixpath.py
===================================================================
--- Lib/posixpath.py	(révision 80417)
+++ Lib/posixpath.py	(copie de travail)
@@ -451,3 +451,22 @@
     if not rel_list:
         return curdir
     return join(*rel_list)
+
+def fs_decode(path):
+    """Decode a path from the file system encoding"""
+    if isinstance(path, str):
+        return path
+    elif isinstance(path, bytes):
+        return path.decode(sys.getfilesystemencoding(), 'surrogateescape')
+    else:
+        raise TypeError("invalid filename type: %s" % type(path).__name__)
+
+def fs_encode(path):
+    """Encode a path to the file system encoding"""
+    if isinstance(path, bytes):
+        return path
+    elif isinstance(path, str):
+        return path.encode(sys.getfilesystemencoding(), 'surrogateescape')
+    else:
+        raise TypeError("invalid filename type: %s" % type(path).__name__)
+
Index: Lib/ntpath.py
===================================================================
--- Lib/ntpath.py	(révision 80417)
+++ Lib/ntpath.py	(copie de travail)
@@ -609,3 +609,18 @@
     if not rel_list:
         return _get_dot(path)
     return join(*rel_list)
+
+def fs_decode(path):
+    """Decode a path from the file system encoding"""
+    if isinstance(path, str):
+        return path
+    else:
+        raise TypeError("invalid filename type: %s" % type(path).__name__)
+
+def fs_encode(path):
+    """Encode a path to the file system encoding"""
+    if isinstance(path, str):
+        return path
+    else:
+        raise TypeError("invalid filename type: %s" % type(path).__name__)
+
Index: Lib/macpath.py
===================================================================
--- Lib/macpath.py	(révision 80417)
+++ Lib/macpath.py	(copie de travail)
@@ -199,4 +199,22 @@
             pass
     return path
 
+def fs_decode(path):
+    """Decode a path from the file system encoding"""
+    if isinstance(path, str):
+        return path
+    elif isinstance(path, bytes):
+        return path.decode(sys.getfilesystemencoding())
+    else:
+        raise TypeError("invalid filename type: %s" % type(path).__name__)
+
+def fs_encode(path):
+    """Encode a path to the file system encoding"""
+    if isinstance(path, bytes):
+        return path
+    elif isinstance(path, str):
+        return path.encode(sys.getfilesystemencoding())
+    else:
+        raise TypeError("invalid filename type: %s" % type(path).__name__)
+
 supports_unicode_filenames = False
Index: Lib/subprocess.py
===================================================================
--- Lib/subprocess.py	(révision 80421)
+++ Lib/subprocess.py	(copie de travail)
@@ -1087,32 +1087,24 @@
                     self._set_cloexec_flag(errpipe_write)
 
                     if _posixsubprocess:
-                        fs_encoding = sys.getfilesystemencoding()
-                        def fs_encode(s):
-                            """Encode s for use in the env, fs or cmdline."""
-                            if isinstance(s, bytes):
-                                return s
-                            else:
-                                return s.encode(fs_encoding, 'surrogateescape')
-
                         # We must avoid complex work that could involve
                         # malloc or free in the child process to avoid
                         # potential deadlocks, thus we do all this here.
                         # and pass it to fork_exec()
 
                         if env:
-                            env_list = [fs_encode(k) + b'=' + fs_encode(v)
+                            env_list = [os.path.fs_encode(k) + b'=' + os.path.fs_encode(v)
                                         for k, v in env.items()]
                         else:
                             env_list = None  # Use execv instead of execve.
                         if os.path.dirname(executable):
-                            executable_list = (fs_encode(executable),)
+                            executable_list = (os.path.fs_encode(executable),)
                         else:
                             # This matches the behavior of os._execvpe().
                             path_list = os.get_exec_path(env)
                             executable_list = (os.path.join(dir, executable)
                                                for dir in path_list)
-                            executable_list = tuple(fs_encode(exe)
+                            executable_list = tuple(os.path.fs_encode(exe)
                                                     for exe in executable_list)
                         self.pid = _posixsubprocess.fork_exec(
                                 args, executable_list,