From: Junio C Hamano <gitster@pobox.com>
Date: Fri, 20 Jan 2012 07:37:13 GMT
Subject: Re: [PATCH] mergetool: Provide an empty file when no base exists
Message-ID: <7vy5t2g6za.fsf@alter.siamese.dyndns.org>
In-Reply-To: <CAJDDKr490XFqGe+y1pa7fnNhPMRE3ZR3=A+_XNUrCA1GZv+wkw@mail.gmail.com>

David Aguilar <davvid@gmail.com> writes:

>>>      local_present  && checkout_staged_file 2 "$MERGED" "$LOCAL"
>>>      remote_present && checkout_staged_file 3 "$MERGED" "$REMOTE"
>>
>> Sorry to be ping-pong-ing like this, but wouldn't we have a similar issue
>> when LOCAL or REMOTE does not exist (e.g. "they modified, we removed")?
>
> Yes.  I'll have a [PATCH v3] soon.

It almost makes me wonder if the obviously simplest change to make
checkout_staged_file create an empty file when the asked-for stage does
not exist, i.e.

	checkout_stage ()
        {
		if test -n "$1"
                then
			... whatever checkout_staged_file() does ...
		else
			>"$4"
                fi
        }

	checkout_stage $base_mode 1 "$MERGED" "$BASE"
	checkout_stage $local_mode 2 "$MERGED" "$LOCAL"
	checkout_stage $remote_mode 3 "$MERGED" "$REMOTE"

Or even:

	checkout_stage ()
	{
		tmpfile=$(...)
                if test $? -eq 0 -a ...
                then
                	mv -- "$(git rev-parse ...)"
		else
			>"$3"
		fi
        }

	checkout_stage 1 "$MERGED" "$BASE"
	checkout_stage 2 "$MERGED" "$LOCAL"
	checkout_stage 3 "$MERGED" "$REMOTE"

as the current checkout_staged_file() does not seem to check errors in any
meaningful way.