Re: [PATCH] completion: fix incorrect bash/zsh string equality check

From: Junio C Hamano <gitster@pobox.com>
Date: Oct 8, 2021, 22:16 UTC
Message-ID: <xmqqh7dri2m1.fsf@gitster.g>
In-Reply-To: <CAMmwyQpP0m6dTdC-L9abZqk9nJkcYy=j4_s0+EdGDr__pykeXQ@mail.gmail.com>

Robert Estelle <robertestelle@gmail.com> writes:

Show 11 quoted lines

> On Fri, Oct 8, 2021 at 1:50 PM Junio C Hamano <gitster@pobox.com> wrote:
>> Would it be equally a valid fix to use "=" instead of "==", or would
>> that change the meaning? This is a bash-only piece of code, so use
>> of [[ ... ]] is not technically incorrect, but if the basic [] works
>> well enough with "=", we should prefer that.
>
> Yes, `[` is preferable for portability and they'd behave the same in
> this case. I consciously chose to use `[[` because that's what all the
> other comparisons in that script use. (I think I noted that in the
> commit message, maybe). I think there's value in consistency, and not
> enough value of `[` over `[[` to justify changing all the other lines.

I do not know if we mind eventual consistency using [] not [[]], but this topic is certainly not about aiming for consistency.

If the difference affects correctness, as brian mentioned, that is a different matter. We should use [ x = y ] in this patch while leaving the existing uses of [[ x == y ]].

Later in a separate patch series, we may need to examine other uses of [[ x == y ]] and correct the ones that do not need/want the pattern matching semantics to use [ x = y ].