Re: [PATCH 1/3] rebase.c: state preserve-merges has been removed

From: Philip Oakley <philipoakley@iee.email>
To: "René Scharfe" <l.s.r@web.de>, "Junio C Hamano" <gitster@pobox.com>
Cc: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
	"Philip Oakley via GitGitGadget" <gitgitgadget@gmail.com>,
	git@vger.kernel.org
Subject: Re: [PATCH 1/3] rebase.c: state preserve-merges has been removed
Date: Fri, 27 May 2022 13:35:03 +0100	[thread overview]
Message-ID: <4ff0622a-9b64-4200-e996-2d1875a52ec8@iee.email> (raw)
In-Reply-To: <32e5088b-35a1-4e8c-098e-18c465a0a0bb@web.de>

Hi René

On 26/05/2022 22:27, René Scharfe wrote:
> Am 26.05.22 um 22:33 schrieb Junio C Hamano:
>> René Scharfe <l.s.r@web.de> writes:
>>
>>>>>   		OPT_SET_INT_F('p', "preserve-merges", &preserve_merges_selected,
>>>>> -			      N_("(DEPRECATED) try to recreate merges instead of "
>>>>> +			      N_("(REMOVED) try to recreate merges instead of "
>>>>>   				 "ignoring them"),
>>>>>   			      1, PARSE_OPT_HIDDEN),
>>>>>   		OPT_RERERE_AUTOUPDATE(&options.allow_rerere_autoupdate),
>>> Anyway, the new help text explaining what the option once did is a bit
>>> confusing.  It would be better to focus on what it's doing now (nothing)
>>> and/or why we still have it (for backward compatibility), I think.
>> Do you mean that we should say "this option used to do such and such
>> but it is now a no-op" after "(REMOVED)" label, instead of the above
>> "this option does such and such"?  I think "(REMOVED)" is a strong
>> enough hint that lets us get away without saying "used to" and "but
>> it is now a no-op", so I can accept both.
>>
>> Or do you mean we should say "(REMOVED) for backward compatibility,
>> does nothing but errors out"?  I would be less in faviour, then.
>> Those who are curious enough to ask --help-all would find it more
>> helpful if we said what it used to do.  Otherwise they wouldn't be
>> asking --help-all in the first place, no?
> When I see an option labeled "REMOVED" then I get confused because a
> thing that says it no longer exists is obviously lying

That's a misunderstanding between the response to the command line 
option, and the described operation of the former sub-command/option.
> -- a removed
> option would simply not be listed.  Here the feature is gone and its
> option remains, but only reports an educational message now.

The needed user response is more that educational. In this case (for the 
Series) they are in a Catch-22 situation, stuck in a no-man's land 
between a preserve merges that has been started, and a Git that won't 
proceed. Currently (prior to the series) Git will even refuse to abort..
>
> Perhaps a better option help text would be something like "no longer
> supported, consider using --rebase-merges instead"?
We'll still need to say _what_ is no longer supported, to ensure the 
user has context. I'd agree with the suggestion aspect (Junio had 
commented similarly).

I suspect this problem could be a long, slow burner. We so rarely remove 
capabilities like this, so it's tricky second guessing how users will 
react, or when they discover the problem.

P.