[Python-Dev] Re: Weird error handling in os._execvpe
Guido van Rossum
Tue, 27 Aug 2002 21:02:23 -0400
> I think the patch associated with this thread has an unintended
> In http://mail.python.org/pipermail/python-dev/2002-August/027229.html
> Zack pointed out three flaws in the original code:
> Third, if an error other than the expected one comes back, the
> loop clobbers the saved exception info and keeps going. Consider
> the situation where PATH=/bin:/usr/bin, /bin/foobar exists but is
> not executable by the invoking user, and /usr/bin/foobar does not
> exist. The exception thrown will be 'No such file or directory',
> not the expected 'Permission denied'.
> The patch, as I understand it, changes the behaviour so as to raise
> the exception "Permission denied" in this case.
> Consider a similar situation in which both /bin/foobar (not executable
> by the user) and /usr/bin/foobar (executable by the user) exist.
> Given the command "foobar", the shell will execute /usr/bin/foobar.
> If I understand the patch correctly, python will give up when it
> encounters /bin/foobar and raise the "Permission denied" exception.
> I believe this just happened to me today. I had a shell script named
> "gcc" in ~/bin (first on my path) some months back. When I was
> finished with it, I just did "chmod -x ~/bin/gcc" and forgot about it.
> Today was the first time since this patch went in that I ran gcc via
> python (using scipy's weave). Boy was I surprised at the message
> "unable to execute gcc: Permission denied"!
> I guess the fix is to save the EPERM exception and keep going
> in case there is an executable later in the path.
This is definitely a bug. Can you or Zack provide a patch?
I've opened a bug report:
--Guido van Rossum (home page: http://www.python.org/~guido/)