>>>d="asdasd"+chr(10)
>>>print os.path.normpath(os.path.join('a/b',d,'d'))
a\b\asdasd
\d

LF or CR cannot be part of a URI (rfc1738)

> LF or CR cannot be part of a URI

But they can be part of a filename, at least on POSIX systems. Are you proposing that only the Windows version of os.path.join strip LF/CR? 

I don't think that it up to the join function to validate the path, and certainly not to modify the substrings. Would you expect it to complain about this? os.path.join('/', 'AUX')? (AUX is a reserved name and forbidden for file names under Windows.)

I don't think it is up to join to validate that the path generated is legal, so I don't think this is a bug in join.

This doesn't sound like a bug. File paths are not URIs: almost all characters are valid in a POSIX filename. Also, sanity checking of user input is up to the caller.

I recommend closing this issue.

The join function should know that it will compose a path with the provided
string, so I think it should complain or ignore ilegal path/filename
components, in regard to the host OS.

But if it is not a valid point of view python-wise, one can check his own
path :P

On Mon, Feb 24, 2014 at 4:03 PM, Steven D'Aprano <report@bugs.python.org>wrote:

>
> Steven D'Aprano added the comment:
>
> > LF or CR cannot be part of a URI
>
> But they can be part of a filename, at least on POSIX systems. Are you
> proposing that only the Windows version of os.path.join strip LF/CR?
>
> I don't think that it up to the join function to validate the path, and
> certainly not to modify the substrings. Would you expect it to complain
> about this? os.path.join('/', 'AUX')? (AUX is a reserved name and forbidden
> for file names under Windows.)
>
> I don't think it is up to join to validate that the path generated is
> legal, so I don't think this is a bug in join.
>
> ----------
> nosy: +stevenjd
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <http://bugs.python.org/issue20761>
> _______________________________________
>

Agreed.