[ python-Bugs-1387483 ] sys.path[0] when executed thru a symbolic link

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Bugs item #1387483, was opened at 2005-12-21 21:23
Message generated for change (Comment added) made by jackjansen
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Category: Macintosh
Group: Python 2.4
>Status: Closed
>Resolution: Works For Me
Priority: 5
Submitted By: Tomasz Kowaltowski (kowaltowski)
Assigned to: Jack Jansen (jackjansen)
Summary: sys.path[0] when executed thru a symbolic link

Initial Comment:
Under certain conditions there is a difference between
Mac OS X and Linux (both 2.4.1) with regard to the
value of the variable sys.path[0] which should contain
the directory from which the script was called.

This difference appears when the script is called
through a symbolic link by a different user. See the
attached example. It should be executed once by the
owner of the TESTPATH directory:

   ~/TESTPATH/sub1/testpath.py
and
   ~/TESTPATH/sub2/testpath.py

In both cases, under Linux and Mac OS X, the result is:

   /home/owner/TESTPATH/sub1

If a different user executes:

   ~owner/TESTPATH/sub1/testpath.py
and
   ~owner/TESTPATH/sub2/testpath.py

he gets the same results under Linux:

   /home/owner/TESTPATH/sub1

but two different results under Mac OS:

   /Users/owner/TESTPATH/sub1
and
   /Users/owner/TESTPATH/sub2

This seems like a minor problem but it breaks my
application because sys.path[0] is the first place to
look for imports!

I am not sure whether this is a Python problem or
something to do with the Mac OS X. My Mac OS X version
is 10.4.3.

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>Comment By: Jack Jansen (jackjansen)
Date: 2005-12-21 21:39

Message:
Logged In: YES 
user_id=45365

I don't see this problem: both users see "sub1" as the working directory. Also 
on 10.4.3.

My guess: there is some problem with the readlink() call that Python uses to 
obtain the real pathname of the script (this is how it finds out sub2/
testpath.py is really sub1/testpath.py. Easy to test: fire up Python as user 2 
and do os.readlink("/Users/owner/TESTPATH/sub2").

I wouldn't be surprised if it is some sort of permission problem (maybe /
Users/owner being mode rwx--x--x so the readlink can't traverse through 
it?).

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