Re: [PATCH] Improve portability of pgweb/load_initial_data.sh

Hi,

On Mon, Nov 08, 2021 at 10:03:50AM +0100, Magnus Hagander wrote:
> Yeah, I think the fact that it says bash is just a "knee-jerk default" and
> not that it ever did either. So I have no problem changing that to sh. I'm
> a bit curious though, as to in which scenario this actually causes a
> problem?

This causes problems on [NixOS][1] which only has `/bin/sh` and
`/usr/bin/env` in the location one would "expect" them.

> The second change I'm less sure about. There are many different things you
> could change to break a script. This is one of them. You could change PATH,
> or you could replace "find" or "xargs" with commands that don't work the
> same way. CDPATH is not a variable that should, I believe, ever be exported
> into non-interactive scripts in the first place.

I didn't realise I was exporting CDPATH, which is ~~probably~~ a mistake
(and would have prevented previous painful and long headaches).

For what it's worth, I use a program I have written that makes use of
CDPATH (and hence requires it to be exported (but I think I will
reconsider the program's usage of CDPATH)).

However I do understand this is an issue with my particular setup.

Attached, is the patch amended without the CDPATH change.

Thanks,

Nils

[1]: https://nixos.org/

> //Magnus
>
> On Sun, Nov 7, 2021 at 5:49 PM Nils <nils(at)nilsand(dot)re> wrote:
>
> > The shell script doesn't use bash extensions and bash may not be
> > available on all systems at that location.
> >
> > If CDPATH is set, in certain cases, the call to cd can result in
> > unwanted behaviour.
> > ---
> > pgweb/load_initial_data.sh | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/pgweb/load_initial_data.sh b/pgweb/load_initial_data.sh
> > index fb16e70c..c419f298 100755
> > --- a/pgweb/load_initial_data.sh
> > +++ b/pgweb/load_initial_data.sh
> > @@ -1,4 +1,4 @@
> > -#!/bin/bash
> > +#!/bin/sh
> >
> > # We keep this in a separate script because using initial_data.xxx in
> > django will overwrite
> > # critical data in the database when running a 'syncdb'. We'd like to
> > keep the ability to
> > @@ -8,7 +8,7 @@ echo WARNING: this may overwrite some data in the database
> > with an initial set o
> > echo 'Are you sure you want this (answer "yes" to overwrite)'
> > read R
> >
> > -cd $(dirname $0)
> > +CDPATH= cd $(dirname $0)
> >
> > if [ "$R" == "yes" ]; then
> > find . -name data.json | xargs ../manage.py loaddata
> > --
> > 2.31.1
> >
> >
> >
> >
>
> --
> Magnus Hagander
> Me: https://www.hagander.net/ <http://www.hagander.net/>
> Work: https://www.redpill-linpro.com/ <http://www.redpill-linpro.com/>