From: Stefan Beller <sbeller@google.com>
Date: Tue, 27 Feb 2018 21:42:38 GMT
Subject: Re: [PATCH] test_must_be_empty: make sure the file exists, not just empty
Message-ID: <CAGZ79kYs8n2NF03S_ieFpVo14zqZMAcTn2x-7+Bm1-2Mwr0=Ng@mail.gmail.com>
In-Reply-To: <xmqqh8q2p1ha.fsf_-_@gitster-ct.c.googlers.com>

On Tue, Feb 27, 2018 at 1:27 PM, Junio C Hamano <gitster@pobox.com> wrote:
> The helper function test_must_be_empty is meant to make sure the
> given file is empty, but its implementation is:
>
>         if test -s "$1"
>         then
>                 ... not empty, we detected a failure ...
>         fi
>
> Surely, the file having non-zero size is a sign that the condition
> "the file must be empty" is violated, but it misses the case where
> the file does not even exist.  It is an accident waiting to happen
> with a buggy test like this:
>
>         git frotz 2>error-message &&
>         test_must_be_empty errro-message
>
> that won't get caught until you deliberately break 'git frotz' and
> notice why the test does not fail.
>
> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Reviewed-by: Stefan Beller <sbeller@google.com>