From: Junio C Hamano <gitster@pobox.com>
Date: Wed, 14 Jan 2015 17:36:25 GMT
Subject: Re: How to prevent empty git commit --amend
Message-ID: <xmqq387db6xy.fsf@gitster.dls.corp.google.com>
In-Reply-To: <xmqqfvbdb7dc.fsf@gitster.dls.corp.google.com>

Junio C Hamano <gitster@pobox.com> writes:

> Matthieu Moy <Matthieu.Moy@grenoble-inp.fr> writes:
>
>> Ivo Anjo <ivo.anjo@ist.utl.pt> writes:
>>
>>> Is there a way to prevent a *git commit --amend** with nothing to
>>> commit from working?
>>> If not, I would like to suggest that this feature would be very helpful :)
>>
>> I don't know any way to let Git do the check for you, but 
>>
>> git diff --staged --quiet || git commit --amend
>>
>> should do it. You can alias it like
>>
>> [alias]
>> 	amend = !git diff --staged --quiet || git commit --amend
>>
>> and then use "git amend".
>
> That would not let you say "git amend Makefile", no?
>
> 	!sh -c 'git diff --cached --quiet "$@" || git commit --amend "$@"' -
>
> or something, perhaps?

Heh, not that but something like that ;-).

 * If we have pathspec, we would want to see if the HEAD and the
   working tree differ at the given paths;

 * Otherwise we would want to see if the HEAD and the index differ.

So it would be more like this, I guess.

	case "$#" in
        0)	git diff --quiet --cached ;;
        *)	git diff --quiet HEAD -- "$@" ;;
	esac || git commit --amend ${1+--} "$@"