[Python-bugs-list] [ python-Bugs-513572 ] isdir behavior getting odder on UNC path

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Bugs item #513572, was opened at 2002-02-05 18:07
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Category: Python Library
Group: Python 2.2
Status: Open
Resolution: None
Priority: 5
Submitted By: Gary Herron (herron)
Assigned to: Mark Hammond (mhammond)
Summary: isdir behavior getting odder on UNC path

Initial Comment:
It's been documented in earlier version of Python on 
windows that os.path.isdir returns true on a UNC 
directory only if there was an extra backslash at the 
end of the argument.  In Python2.2 (at least on 
windows 2000) it appears that *TWO* extra backslashes 
are needed.

Python 2.2 (#28, Dec 21 2001, 12:21:22) [MSC 32 bit 
(Intel)] on win32
Type "help", "copyright", "credits" or "license" for 
more information.
>>>
>>> import os
>>> os.path.isdir('\\trainer\island')
0
>>> os.path.isdir('\\trainer\island\')
0
>>> os.path.isdir('\\trainer\island\\')
1
>>>

In a perfect world, the first call should return 1, 
but never has.  In older versions of python, the 
second returned 1, but no longer.

In limited tests, appending 2 or more backslashes to 
the end of any pathname returns the correct answer in 
both isfile and isdir.


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>Comment By: Tim Peters (tim_one)
Date: 2002-02-08 15:33

Message:
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user_id=31435

BTW, it occurs to me that this *may* be a consequence of 
whatever was done in 2.2 to encode/decode filename strings 
for system calls on Windows.  I didn't follow that, and 
Mark may be the only one who fully understands the details.

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Comment By: Tim Peters (tim_one)
Date: 2002-02-08 15:17

Message:
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Here's the implementation of Windows isdir():

def isdir(path):
.    """Test whether a path is a directory"""
.    try:
.        st = os.stat(path)
.    except os.error:
.        return 0
.    return stat.S_ISDIR(st[stat.ST_MODE])

That is, we return whatever Microsoft's stat() tells us, 
and our code is the same in 2.2 as in 2.1.  I don't have 
Win2K here, and my Win98 box isn't on a Windows network so 
I can't even try real UNC paths here.  Reassigning to MarkH 
in case he can do better on either count.

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Comment By: Guido van Rossum (gvanrossum)
Date: 2002-02-08 14:05

Message:
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user_id=6380

Tim, I hate to do this to you, but you're the only person I
trust with researching this. (My laptop is currently off the
net again. :-( )


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