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

From: brian m. carlson <sandals@crustytoothpaste.net>
Date: Oct 8, 2021, 20:57 UTC
Message-ID: <YWCwvOdW/L5aMpr7@camp.crustytoothpaste.net>
In-Reply-To: <xmqqbl3zjl5y.fsf@gitster.g>

On 2021-10-08 at 20:50:33, Junio C Hamano wrote:

Show 12 quoted lines

> "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