Hi

The behavior of os.realpath function on Linux is different from the one 
presented by the system. 
Although the path (pointing to the linked dir) is correct
and is recognized by os.path.exists once it is resolved
by the realpath() it does not exist - at the end of the 
resolved path you will see the additional parent directory name.
you will see
..... /two/two at the end of the path.

Below is the code that shows the issue.

def linkGen():
  import os
  print os.getcwd()
  test = "./test"
  os.system( "rm -rf " + test  )  
  #os.mkdir( test )
  os.makedirs( test + "/one" )
  os.makedirs( test + "/two" )
  os.symlink( "../two", test + "/two/this_dir" )
  os.symlink( "../two/this_dir/this_dir/this_dir/this_dir/", test + 
"/one/that_dir" )
  print test + "/one/that_dir", "EXISTS?",   
  print os.path.exists( test + "/one/that_dir" )
  print os.path.realpath( test + "/one/that_dir" ), "EXISTS?", 
  print os.path.exists( os.path.realpath( test + "/one/that_dir" ) )
  os.system( "ls -l " + test + "/one/that_dir" )
  # the line above will show that system can see the directory just fine

linkGen()

Hi
I meant of course 
os.path.realpath()
Sylwester

I've provided a patch.

I've also added a new test, and it passes.

I've just found a similar bug:
http://bugs.python.org/issue1646838

However, does os.path.realpath's behavior have to be as the one
specified by the POSIX standard (
http://www.kernel.org/doc/man-pages/online/pages/man3/realpath.3.html )?
If we wanted to follow the standard, we should break the
retro-compatibility, since we should raise an exception in the case the
path passed as argument doesn't exist.

Marco,

Thanks for looking deeper into it.
I would like to check the solution ASAP.
We have really crazy dir structure which can catch a lot of
the unexpected problems with paths, links, circular links etc.

Should I expect the new version to generate the exception
as you suggested?

Best Regards,
    Sywlester Warecki

Marco Buccini wrote:
> Marco Buccini <marcusbu@gmail.com> added the comment:
>
> I've just found a similar bug:
> http://bugs.python.org/issue1646838
>
> However, does os.path.realpath's behavior have to be as the one
> specified by the POSIX standard (
> http://www.kernel.org/doc/man-pages/online/pages/man3/realpath.3.html )?
> If we wanted to follow the standard, we should break the
> retro-compatibility, since we should raise an exception in the case the
> path passed as argument doesn't exist.
>
> ----------
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <http://bugs.python.org/issue6975>
> _______________________________________
>
>

>Thanks for looking deeper into it.
>I would like to check the solution ASAP.
>We have really crazy dir structure which can catch a lot of
>the unexpected problems with paths, links, circular links etc.

Oh well, so you can see if the patch works correctly on all paths :)
 
>Should I expect the new version to generate the exception
>as you suggested?

 
Unfortunately I'm not God, so I cannot change the "code" of the current
implementation of os.path.realpath (raising an OSError exception)
without breaking any existing code. 
So, consider using the current implementation of os.path.realpath ;)
If you experience other strange behaviors, then open a new bug report.

Bye!