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From:   Junio C Hamano <gitster@pobox.com>
To:     Robert Estelle <robertestelle@gmail.com>
Cc:     Robert Estelle via GitGitGadget <gitgitgadget@gmail.com>,
        git@vger.kernel.org
Subject: Re: [PATCH] completion: fix incorrect bash/zsh string equality check
References: <pull.1096.git.git.1633642772432.gitgitgadget@gmail.com>
        <xmqqbl3zjl5y.fsf@gitster.g>
        <CAMmwyQpP0m6dTdC-L9abZqk9nJkcYy=j4_s0+EdGDr__pykeXQ@mail.gmail.com>
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        <CAMmwyQp7ChC7RZAZX4Y3UyAghOAmvHA7e3BBJonGYJNoSc+nFA@mail.gmail.com>
Date:   Fri, 08 Oct 2021 16:09:01 -0700
In-Reply-To: <CAMmwyQp7ChC7RZAZX4Y3UyAghOAmvHA7e3BBJonGYJNoSc+nFA@mail.gmail.com>
        (Robert Estelle's message of "Fri, 8 Oct 2021 15:26:30 -0700")
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Robert Estelle <robertestelle@gmail.com> writes:

> The choice between the two does not affect correctness, it's purely
> stylistic here. It only would affect correctness for unquoted
> arguments or extended comparison operators. Those *are* in use
> elsewhere in this script and force the use of `[[` in those places.
>
> Keep in mind also that this is an autocomplete script. Although it's
> sourced by both bash and zsh, it does not make sense to attempt to
> make it work for bare POSIX sh.

Nobody is trying to.  It is more for reducing the risk of people
shooting their foot by cutting and pasting without thinking.

When you do not mean pattern matching and want exact matching, even
if it is guaranteed that the data you pass through the codepath does
not have pattern to cause the former, hence the distinction between
[[ x == y ]] and [ x = y ] does not make a difference, that is a
mere happenstance, and use of [ x = y ] is the correct thing to do
in such a case.