Re: [PATCH v3 4/4] format-patch: add format.cover-letter configuration

From: Junio C Hamano <gitster@pobox.com>
Date: Apr 7, 2013, 17:22 UTC
Message-ID: <7v38v25k8b.fsf@alter.siamese.dyndns.org>
In-Reply-To: <vpqbo9qfh1y.fsf@grenoble-inp.fr>

Matthieu Moy <Matthieu.Moy@grenoble-inp.fr> writes:

Show 9 quoted lines

>> Wouldn't this work for both cases?
>>
>> % git -c format.coverletter=auto format-patch
>
> Then, what's the point in having a --cover-letter option?
>
> "git -c" is a good last-chance solution, but when we provide the same
> feature as a command-line option and as a configuration option, I can
> see no reason to add subtle difference between them.

I do not see a good reason to resist consistency by suggesting a workaround. We may do so ourselves when responding to an end user bug report "I cannot countermand X from the command line" as a first response "In the meantime you can work it around like so", but that is as you said a last-resort workaround and does not justify why the command line interface is lacking an obvious override.

But I think --cover-letter=auto I made was a bad suggestion. An optional parameter to a command line option is generally bad, as it makes the parsing ambiguous [*1*], and turning what traditionally was a boolean without any parameter into one that takes an optional parameter is even worse.

We should instead add this as a new feature, --auto-cover-letter, or something, i.e. the synopsis will have these as the choices

    [--[no-]cover-letter|--auto-cover-letter]

and the last one would win (e.g. "--cover-letter --auto-cover-letter" would mean "auto").

[Footnote]

*1* Does "--cover-letter yes" mean "--cover-letter=yes" aka "please use cover letter" or is it "--cover-letter" (please use cover letter) followed by an unrelated command line argument "yes"?