[Python-ideas] Support os.path.join for Windows paths on Posix

[Steven D'Aprano]

On Wed, Oct 30, 2013 at 05:35:57PM -0500, Ryan Gonzalez wrote:
> The recent thread/post/whatever on os.path.join has gotten me thinking. Say
> I wanted to join a Windows path...on Ubuntu. This is what I get:
[...]
> Isn't something wrong there? My idea: check for \'s in the path. If there
> are any, assume \ is the path separator, not /.

Others have already pointed out that using ntpath is the right solution 
for this problem, but I wanted to mention that the suggestion to guess 
the path separator based on the path is risky. Backslashes are legal in 
file and directly names on POSIX systems (Mac, Unix, Linux etc), which 
means that sometimes os.join will be given a POSIX path containing 
backslashes, in which case it will wrongly guess it is a Windows path.

os.path.join("ab\\c", "d", "file.txt")

on POSIX ought to give the path containing two directories and a file 
name 'ab\\c/d/file.txt' but with the guesser will generate a single file 
name 'ab\\c\\d\\file.txt'.



-- 
Steven