From mboxrd@z Thu Jan  1 00:00:00 1970
From: Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH] rebase -i: avoid 'git reset' when possible
Date: Mon, 02 Mar 2009 16:57:45 -0800
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Cc: Sverre Rabbelier <srabbelier@gmail.com>,
	Stephen Haberman <stephen@exigencecorp.com>,
	"Shawn O. Pearce" <spearce@spearce.org>,
	Thomas Rast <trast@student.ethz.ch>,
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To: Johannes Schindelin <Johannes.Schindelin@gmx.de>
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Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:

> Or even
>
> 	current=$ONTO
> 	fd=3
> 	while read command sha1 rest
> 	do
> 		case "$fd,$command,$current" in
> 		3,pick,"$sha1"*|t,p,"$sha1"*)
> 			current=$sha1
> 			;;
> 		*)
> 			fd=1
> 			;;
> 		esac
> 		echo "$command $sha1 $rest" >&$fd
> 	done < "$TODO" > "$TODO.new" 3>> "$DONE" &&
> 	mv "$TODO.new" "$TODO"
>
> Hmm?

Certainly.

Even though "3 means we haven't found a non-pick yet" feels slightly
hacky, the logic is contained in this small loop and I do not see it as a
problem.  As long as you are sure $ONTO and all sha1 can be compared
without running them through rev-parse, avoiding rev-parse per iteration
is a very attractive optimization.