From: Karthik Nayak <karthik.188@gmail.com>
Date: Fri, 19 Jul 2024 08:33:21 GMT
Subject: Re: [PATCH v5 5/6] check-whitespace: detect if no base_commit is provided
Message-ID: <CAOLa=ZQhcb7O4i9E=Xn+9ZbaNhiY0gzD_a2kTqriegF2o-Eeyw@mail.gmail.com>
In-Reply-To: <xmqqfrs6ycc3.fsf@gitster.g>

Junio C Hamano <gitster@pobox.com> writes:

> Karthik Nayak <karthik.188@gmail.com> writes:
>
>> +    - |
>> +      R=${CI_MERGE_REQUEST_TARGET_BRANCH_SHA-${CI_MERGE_REQUEST_DIFF_BASE_SHA?}}
>> +
>> +      if test -z "$R"
>> +      then
>> +        echo "CI_MERGE_REQUEST_DIFF_BASE_SHA should always exist!"
>> +        exit 1
>> +      fi
>
> The same comment applies as the previous step.
>
> 	R=${A-${B:?}} || exit
>
> should be sufficient.
>
> A demonstration.
>
>         $ unset A; unset B; C=${A-${B:?}} && echo "C=$C"
>         bash: B: parameter null or not set
>         $ A=a; unset B; C=${A-${B:?}} && echo "C=$C"
>         C=a
>         $ unset A; B=; C=${A-${B:?}} && echo "C=$C"
>         bash: B: parameter null or not set
>         $ unset A; B=b; C=${A-${B:?}} && echo "C=$C"
>         C=b
>         $ A=a; B=b; C=${A-${B:?}} && echo "C=$C"
>         C=a
>
> Note that the broken case we do not see C=<value> becaues the
> assignment fails with non-zero status.
>
> Thanks.

Thanks Junio for explaining with examples, really nice of you! I'm on
the fence with this, even the existing change from the previous more
verbose code. I know this is shorter, but it is always more readable to
use the longer version with 'test'. I find it hard to remember the
specifics. But I don't really care which one makes it in the end.

Let me know if you think it is worth a reroll.

Thanks