Index: Lib/os.py
===================================================================
--- Lib/os.py	(révision 85851)
+++ Lib/os.py	(copie de travail)
@@ -382,18 +382,24 @@
     *env* must be an environment variable dict or None.  If *env* is None,
     os.environ will be used.
     """
+    import warnings
+
     if env is None:
         env = environ
 
     try:
-        path_list = env.get('PATH')
-    except (TypeError, BytesWarning):
+        # Catch BytesWarning
+        with warnings.catch_warnings():
+            path_list = env.get('PATH')
+    except (TypeError,):
         path_list = None
 
     if supports_bytes_environ:
         try:
-            path_listb = env[b'PATH']
-        except (KeyError, TypeError, BytesWarning):
+            # Catch BytesWarning
+            with warnings.catch_warnings():
+                path_listb = env[b'PATH']
+        except (KeyError, TypeError):
             pass
         else:
             if path_list is not None: