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

From: "brian m. carlson" <sandals@crustytoothpaste.net>
To: Junio C Hamano <gitster@pobox.com>
Cc: Robert Estelle via GitGitGadget <gitgitgadget@gmail.com>,
	git@vger.kernel.org, Robert Estelle <robert.estelle@gmail.com>,
	Robert Estelle <robertestelle@gmail.com>
Subject: Re: [PATCH] completion: fix incorrect bash/zsh string equality check
Date: Fri, 8 Oct 2021 20:57:32 +0000	[thread overview]
Message-ID: <YWCwvOdW/L5aMpr7@camp.crustytoothpaste.net> (raw)
In-Reply-To: <xmqqbl3zjl5y.fsf@gitster.g>

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On 2021-10-08 at 20:50:33, Junio C Hamano wrote:
> "Robert Estelle via GitGitGadget" <gitgitgadget@gmail.com> writes:
> 
> >     This fixes an error in contrib/completion/git-completion.bash caused by
> >     the incorrect use of == (vs. single =) inside a basic [/test command.
> >     Double-equals == should only be used with the extended [[ comparison.
> 
> Curious.
> 
> 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.

It's actually preferable in most cases to use [ and = rather than [[ and
==, because the former looks for strict equality and the latter looks
for pattern matching.  If one is placing a glob pattern on the right
side, then [[ and == can be desirable, but otherwise it's better to
stick to the POSIX syntax.
-- 
brian m. carlson (he/him or they/them)
Toronto, Ontario, CA

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