Re: [PATCH libgpiod v2 2/4] tools: tests: use "$@" instead of $*

[Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>]

On Wed, May 29, 2024 at 09:44:40PM +0800, Kent Gibson wrote:
> On Wed, May 29, 2024 at 04:27:00PM +0300, Andy Shevchenko wrote:
> > On Wed, May 29, 2024 at 09:18:47PM +0800, Kent Gibson wrote:
> > > On Wed, May 29, 2024 at 04:08:49PM +0300, Andy Shevchenko wrote:
> > > > On Tue, May 28, 2024 at 07:39:10AM +0800, Kent Gibson wrote:
> > > > > On Mon, May 27, 2024 at 07:17:37PM +0300, Andy Shevchenko wrote:
> > > > > > On Mon, May 27, 2024 at 08:44:20PM +0800, Kent Gibson wrote:
> > > > > > > On Mon, May 27, 2024 at 02:02:34PM +0200, Bartosz Golaszewski wrote:

...

> > > > > > > >  assert_fail() {
> > > > > > > > -	$* || return 0
> > > > > > > > -	fail " '$*': command did not fail as expected"
> > > > > > > > +	"$@" || return 0
> > > > > > > > +	fail " '$@': command did not fail as expected"
> > > > > > > >  }
> > > > > > >
> > > > > > > Ironically, shellcheck doesn't like the '$@' in the fail string[1], so you
> > > > > > > should use $* there.
> > > > > >
> > > > > > But why does it do like this?
> > > > >
> > > > > Read the link[1].
> > > >
> > > > Okay, this is only for some debug / error messages. Still if one wants to have
> > > > clear understanding on what has been passed to some function, $* is not a
> > > > correct option. Also note the single quotes, shouldn't that protect from the
> > > > arguments loss?
> > >
> > > That's right - I was only referring to this particular case where a
> > > string is being constructed.  Wasn't that clear?
> >
> > I meant that if you want to have this knowledge in the debug / error message,
> > you will fail with $*, that's why I consider shellcheck is incorrect.
> >
> > Ex.
> >
> > I have
> >
> > 	foo bar "baz bar2"
> >
> > and I want
> >
> > 	"ERROR: 'foo bar "baz bar2"' failed"
> >
> > type of message.
> >
> 
> Fair point, but $@ doesn't give you that either:
> 
> boo() {
> 	echo "star '$*'"
> 	echo "hash '$@'"
> }
> 
> boo foo bar "baz bar2"
> 
> gives:
> 
> star 'foo bar baz bar2'
> hash 'foo bar baz bar2'

Oh, this is unfortunate. It seems entire model with quotation depends on the
commands, printf makes it different, print -r -- makes it better, though, if
one uses non-space IFS for it.

> Is there any form that gives you the format you want?

Yes, but it requires an iteration over arguments, roughly something like below
(which is not yet what I want, but closer):

	for a in "$@"; do
		echo -n '"$a" ' # echo -n seems not portable IIRC
	done
	echo

-- 
With Best Regards,
Andy Shevchenko