From: Eric Sunshine <sunshine@sunshineco.com>
Date: Mon, 12 Apr 2021 18:48:43 GMT
Subject: Re: [PATCH 01/16] check-non-portable-shell: complain about "test" a/-o instead of &&/||
Message-ID: <CAPig+cSiwq3KwSLyfNezx77FvLMu0gDjLq2jCKVnLQ-uVXP3Yw@mail.gmail.com>
In-Reply-To: <xmqqsg3vcpqv.fsf@gitster.g>

On Mon, Apr 12, 2021 at 2:38 PM Junio C Hamano <gitster@pobox.com> wrote:
> Eric Sunshine <sunshine@sunshineco.com> writes:
> >> +       /\btest\s+-[a-z]\s+.*?\s+-a\s+/ and err '"test A && test B" preferred to "test A -a B"';
> >> +       /\btest\s+-[a-z]\s+.*?\s+-o\s+/ and err '"test A || test B" preferred to "test A -o B"';
> >
> > These will only match the simplistic forms of `test -X blah` (where
> > "-X" is some single letter option), but will miss expressions such as
> > `test "$foo" = bar`. Crafting a regex to match more generally would be
> > non-trivial, so this simpler match is a reasonable start. Okay.
>
> Would it be a trivial improvement to do
>
>     'test', followed by anything other than '&' or '|', and then
>     followed by '-a' or '-o'
>
> instead?

That seems plausible and trivial enough. In fact, I think it
eliminates a source of false-positives that Ævar's pattern can report,
such as:

    test whatever && ls -a foo

and

    test whatever && foo -o outfile

among others.