Re: [PATCH v2 8/8] tests: disallow the use of abbreviated options (by default)

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Apr 17, 2019, 12:07 UTC
Message-ID: <nycvar.QRO.7.76.6.1904171354270.46@tvgsbejvaqbjf.bet>
In-Reply-To: <xmqqef63qt5e.fsf@gitster-ct.c.googlers.com>

Hi Junio,

On Mon, 15 Apr 2019, Junio C Hamano wrote:

Show 42 quoted lines

> Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
>
> > On Mon, 15 Apr 2019, Junio C Hamano wrote:
> >
> >> Junio C Hamano <gitster@pobox.com> writes:
> >>
> >>
> >> > Do you mean more like
> >> > ...
> >> > I think I can agree with either of the two positions...
> >>
> >> I am guessing from the earlier iteration that you wanted to say
> >> "unless it is given explicitly, we turn it on".
> >>
> >> As this last-minute style update that was botched, and a typofix in
> >> the proposed log message in 8/8, are the only differences, let me
> >> locally fix 8/8 up and replace it.
> >
> > Sure. I still would like the `isset` thing, as it makes things more
> > consistent, but I'll not fight for it.
>
> ${var:+isset} is fine.  Instead of
>
> +# Disallow the use of abbreviated options in the test suite by default
> +if test -z "${GIT_TEST_DISALLOW_ABBREVIATED_OPTIONS}"
> +then
> +	GIT_TEST_DISALLOW_ABBREVIATED_OPTIONS=true
> +	export GIT_TEST_DISALLOW_ABBREVIATED_OPTIONS
> +fi
> +
>
> if you used
>
> 	if test -z "${GIT_TEST_DISALLOW_ABBREVIATED_OPTIONS:+isset}"
> 	then
> 		...
>
> I won't object.  After all, I know I introduced :+isset pattern to
> our shell script codebase as there are cases where it makes the
> result easier to follow.
>
> But the thing is that your patch had the polarity inverted.

Ah! I finally understand what you are saying. Took me a while, sorry.

> Where you must say "if this thing is not set, assign this value", you
> said "if this thing is set, assign this value", which was totally bogus.
> As long as that is corrected, that's fine.

Of course! It should be `-z` instead of `-n` there.

Show 17 quoted lines

> Having said that.
>
> When you check if the variable is set, use of the ":+isset" pattern
> makes the result often easier to follow by explicitly letting us
> compare with an explicit "isset" token, e.g.
>
> 	case ",${VAR1:+isset},${VAR2:+isset}," in
> 	*,isset,*)	: at least one is set ;;
> 	*)		: neither is set ;;
> 	esac
>
> This *does* make the code simpler and easier.  But when checking for
> "is it not set?", you can compare with an explicit literal "" and
> that comparison is plenty clear enough.  You won't get as much
> benefit as the "is it set?" test would out of the pattern.  I would
> not say that it is pointless to use the ":+isset" pattern when
> checking "is it not set?", but it is very close.

Well, there is also the subtelty that somebody might *want* to set that environment variable to the empty string (and obviously they would not deem it appropriate for us to override their choice).

But I do have bigger fish to fry, so if you're fine with the `isset` thing (fixed, of course), please go for it. If you'd prefer the version without it, that's fine enough with me, too.

Ciao, Dscho