Re: [PATCH v4 1/1] MacOS: precompose_argv_prefix()

From: "Torsten Bögershausen" <tboegi@web.de>
To: Junio C Hamano <gitster@pobox.com>
Cc: git@vger.kernel.org, random_n0body@icloud.com,
	levraiphilippeblain@gmail.com
Subject: Re: [PATCH v4 1/1] MacOS: precompose_argv_prefix()
Date: Fri, 5 Feb 2021 18:31:56 +0100	[thread overview]
Message-ID: <20210205173156.6ypl2q56r6gzutac@tb-raspi4> (raw)
In-Reply-To: <xmqqh7msbxzy.fsf@gitster.c.googlers.com>

On Wed, Feb 03, 2021 at 02:13:53PM -0800, Junio C Hamano wrote:
> Junio C Hamano <gitster@pobox.com> writes:
>
> > Just as the prefix-less variant was idempotent and that was the
> > reason why cmd_diff_files() had its own precompose() even if the
> > incoming argv[] is supposed to be already precomposed because it
> > was processed in another call to precompose() in run_builtin(),
> > this patch keeps these seemingly redundant calls, because it is not
> > meant as a clean-up but as a bugfix for the prefix part.
> >
> > OK. ... Ah, no, the call in run_builtin() is a new thing.  We didn't
> > have it, and the redundant call is what this patch introduced, so
> > we need to be a bit more careful about the analysis here.  It is one
> > thing to say "we leave the existing iffy code and address only a
> > single bug" and do so.  It is entirely different to say so and then
> > do "we introduce an iffy code and address only a single bug".  We
> > need to admit that what we added _is_ iffy but supposed to be safe.
> > Just saying "it is supposed to be safe" without saying why it is
> > iffy is dishonest and does not help future developers who may want
> > to jump in and clean the code.
> >
> > Perhaps
> >
> > 	Now add it into git.c::run_builtin() as well.  Existing
> > 	precompose calls in diff-files.c and others would become
> > 	redundant but because we do not want to make sure that there
> > 	is no way for the control to reach them without passing
> > 	run_builtin(), we'll keep them in place just in case.  The
> > 	calls to precompose() are idempotent so it should not hurt.
> >
> > or something?
>
> FYI, I've tweaked the proposed log message like the following before
> queuing.  I think that would be explicit enough to remind us that we
> may be able to improve the situation fairly easily.
>

Thanks for helping me out.
That gives me some time to look deeper and prepare more test cases
ana a then cleanup on top of this patch (later).