GNU bug report logs - #52117
[core-updates-frozen] [PATCH 0/6] Fix Julia packages.

Previous Next

Full log

Message #46 received at 52117 <at> debbugs.gnu.org (full text, mbox):

From: zimoun <zimon.toutoune <at> gmail.com>
To: Maxim Cournoyer <maxim.cournoyer <at> gmail.com>
Cc: 52117 <at> debbugs.gnu.org
Subject: Re: bug#52117: [core-updates-frozen] [PATCH 0/6] Fix Julia packages.
Date: Mon, 29 Nov 2021 15:10:01 +0100

Hi Maxim,

On Sat, 27 Nov 2021 at 21:57, Maxim Cournoyer <maxim.cournoyer <at> gmail.com> wrote:

> No, it would invoke julia with the following argv list: "julia"
> "-depwarn=yes" "" [...];
>
> My point is that invoke is equivalent to doing an execlp system call;
> and the arguments get passed as a list (including that empty string
> argument when parallel-tests? is #f).  Whether this works or not is up
> to the application, so I'd suggest not relying on it.  Consider for
> example:
>
> (execlp "python" "python" "" "-c" "print('hello')")
> /gnu/store/cwqv4z5bvb5x6i0zvqgc1j1dnr6w9vp8-profile/bin/python: can't
> find '__main__' module in
> '/home/maxim/src/guix-core-updates-next/gnu/packages/'

Thanks for the explanations.


> It fails because it interprets the empty string argument as the current
> directory, apparently.  If that works with the above Julia invocation,
> that's great, but it doesn't make it cleaner in my opinion :-).

Indeed, and it is expected to fail because:

--8<---------------cut here---------------start------------->8---
def _get_main_module_details(error=ImportError):
    # Helper that gives a nicer error message when attempting to
    # execute a zipfile or directory by invoking __main__.py
    main_name = "__main__"
    try:
        return _get_module_details(main_name)
    except ImportError as exc:
        if main_name in str(exc):
            raise error("can't find %r module in %r" %
                              (main_name, sys.path[0]))
        raise
--8<---------------cut here---------------end--------------->8---

It allows to do:

        $ mkdir /tmp/foo
        $ echo print(42) > /tmp/foo/__main__.py
        $ python /tmp/foo

Therefore, this

        $ python '' -c '0'

just fails.  Contrary to,

        $ cd /tmp/foo
        $ python '' -c '0'

which just passes.  To me, it is an oddity of the Python command-line
which silently accepts a path; it is not documented by “python -h”.

Anyway, I agree that the behaviour when passing "" is up to the
application, therefore it should be avoided.


Cheers,
simon

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.