Re: Google Summer of Code 2013 (GSoC13)

From: Junio C Hamano <gitster@pobox.com>
Date: Feb 18, 2013, 22:37 UTC
Message-ID: <7vehgd9rkg.fsf@alter.siamese.dyndns.org>
In-Reply-To: <20130218210709.GC27308@sigill.intra.peff.net>

Jeff King <peff@peff.net> writes:

Show 19 quoted lines

> This is not related to GSoC anymore, but I think handling multiple
> versions is already pretty easy. You can just install to
> "$HOME/local/git/$TAGNAME" or similar, and then symlink the "bin/git"
> binary from there into your PATH as git.$TAGNAME (e.g., git.v1.7.8). Git
> already takes care of the messy bits, like making sure sub-programs are
> invoked from the same git version.
>
> I already do this automagically with this script:
>
>   https://github.com/peff/git/blob/meta/install/prefix
>
> I just set "prefix" in the Makefile based on the script, and when I
> "make install" tags or topic branches, they go to the right place (and
> the "links" script in the same directory maintains the symlinks for me).
>
> I never bothered to even submit those scripts to contrib, because I
> figured they were so specific to my setup, and to keeping dozens of git
> versions around (when debugging, it's nice to be able to check an old
> version's behavior without even having to build it).

Yeah, I have been using the Make (in the todo branch, to be checked out in Meta/ subdirectory of the working tree) script for exactly this. After tagging a release, I'd do

	git checkout -B snap v1.8.1.3
        Meta/Make install install-doc

to install them in $inst_prefix/git-snap-v1.8.1.3. A "rungit" script can then be used like:

	rungit v1.7.0 checkout blah

-- rungit script -- >8 -- rungit script -- #!/bin/sh # Run various vintage of git

variant="${0##*/}" &&
: ${RUNGIT_BASE=$HOME/g/$(getarch)} &&
case "$variant" in
rungit)
	case $# in 
	0)
		echo >&2 "which version?"
		exit 1
		;;
	esac
	variant=$1
	shift
	;;
esac &&
case "$variant" in
-l)
	for d in "$RUNGIT_BASE/"git-*/bin/git
	do
		d=$(basename ${d%/bin/git})
		d=${d#git-}
		d=${d#snap-}
		echo "$d"
	done
	exit
	;;
git-*)
	variant=${variant#git-} ;;
v[0-9]*)
	variant=snap-$variant ;;
esac &&
d="$RUNGIT_BASE/git-$variant" &&
if test -f "$d/bin/git"
then
	exec "$d/bin/git" "$@"
else
	echo >&2 "$variant: No such variant for $a"
	exit 1
fi