FTPHost.walk fails when the argument is a unicode string and the tree contains non-ASCII characters

[schwa]

When FTPHost.walk is used to examine a filesystem tree which somewhere contains a non-7-bit-ASCII character in a name and the argument passed in is any unicode string, the walk method implicitly will raise a UnicodeEncodeError.

Imagine this directory structure:

some_dir
    some_stränge_file

then

ftp_host.walk(u"some_dir")

will cause a UnicodeEncodeError in posixpath like:

   File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/posixpath.py", line 70, in join
     path += '/' + b
UnicodeDecodeError: 'ascii' codec can't decode byte 0xdf in position 41: ordinal not in range(128)

(original  report by Henning Hraban Ramm - thanks!)

[schwa]

As pointed out in  this mail, FTP has no concept of encodings. As the encoding of the directories and files on the remote side is unknown, there's no convenient solution.

At the moment, I think the most appropriate approach is to have a method fail as early as possible if it accepts remote paths and gets a unicode string for them.

A solution might be something like:

def walk(self, root):
    # If `root` isn't ASCII, fail now instead of later.
    # Otherwise, continue with a byte string.
    root = str(root)
    ...

[schwa]

I put this off until ftputil 2.5.1. I'll have to go through all the methods and see how they're affected, and I don't want to delay the release of ftputil 2.5 final even more after the apparently long beta phase.

[schwa]

Fixed in commits [7ee81a2ca43a] and [8c59e4da5479].