# HG changeset patch
# User Ludovic Chabant <ludovic@chabant.com>
# Date 1438441793 25200
# Node ID 6ef89b31dddaf50d8cbcb8ee6603e4530ed4d64c
# Parent  1856e7aa6ce8a581f20b52312e454caab183b34f
internal: Fix a severe bug with the file-system wrappers on OSX.

`os.walk` is expected to support modifying its return values `dirnames` and
`filenames` so that you can filter out items that need to be iterated upon.
I was previously returning a different list in the wrappers, which means
filtering was completely broken.

diff -r 1856e7aa6ce8 -r 6ef89b31ddda piecrust/osutil.py
--- a/piecrust/osutil.py	Fri Jul 31 23:35:55 2015 -0700
+++ b/piecrust/osutil.py	Sat Aug 01 08:09:53 2015 -0700
@@ -13,8 +13,8 @@
     def _walk(top, **kwargs):
         for dirpath, dirnames, filenames in os.walk(top, **kwargs):
             dirpath = _from_osx_fs(dirpath)
-            dirnames = list(map(_from_osx_fs, dirnames))
-            filenames = list(map(_from_osx_fs, filenames))
+            dirnames[:] = list(map(_from_osx_fs, dirnames))
+            filenames[:] = list(map(_from_osx_fs, filenames))
             yield dirpath, dirnames, filenames
 
     def _listdir(path='.'):