[PATCH] contrib/workdir: add a simple script to create a working directory

Add a simple script to create a working directory that uses symlinks
to point at an exisiting repository.  This allows having different
branches in different working directories but all from the same
repository.

Based on a description from Junio of how he creates multiple working
directories[1].  With the following caveat:

"This risks confusion for an uninitiated if you update a ref that
is checked out in another working tree, but modulo that caveat
it works reasonably well."

[1] http://article.gmane.org/gmane.comp.version-control.git/41513/

Signed-off-by: Julian Phillips <redacted>
---

On Mon, 26 Mar 2007, Junio C Hamano wrote:

Julian Phillips [off-list ref] writes:

quoted

Add a simple script to create a working directory that uses symlinks
to point at an exisiting repository.  This allows having different
branches in different working directories but all from the same
repository.  A poor-man's .gitlink if you will.

I would not call it poor-man's.  It is 'without complexity' and
that is a good thing, especially when you are not doing any
submodule stuff.

True, it may not be as wizzy as .gitlink no doubt will be, but I
think it will suit me nicely.

I also thought it was worth a reference to your caveat, but perhaps
that would be better as a comment in the code?

quoted

+# create the links to the original repo
+for x in config refs logs/refs objects info hooks packed-refs remotes

rr-cache

quoted

+do
+	case ${x} in
+	*/*)
+		mkdir -p $(dirname ${new_workdir}/.git/${x});
+		;;
+	esac
+	ln -s ${orig_git}/.git/${x} ${new_workdir}/.git/${x};
+done

I think the above list "for x" is correct, but probably the code
wants to comment on why it specifically excludes logs/HEAD from
the symlinked set ;-).

Good point.

quoted

+# now setup the workdir
+cd ${new_workdir};
+# create a fake HEAD, to stop checkout complaining
+echo "ref: refs/heads/master" > .git/HEAD;
+# now checkout the branch that was asked for
+git checkout ${branch};

If ${branch} was 'master', does this do a checkout?  I think -f
might be needed.

It worked when I tried it ... but -f might be worth it anyway.


 contrib/workdir/git-new-workdir |   55 +++++++++++++++++++++++++++++++++++++++
 1 files changed, 55 insertions(+), 0 deletions(-)
 create mode 100755 contrib/workdir/git-new-workdir

diff --git a/contrib/workdir/git-new-workdir b/contrib/workdir/git-new-workdir
new file mode 100755
index 0000000..5bfd87e
--- /dev/null
+++ b/contrib/workdir/git-new-workdir

@@ -0,0 +1,55 @@
+#!/bin/bash
+
+function usage () {
+	echo "usage:" $1;
+	exit 127;
+}
+
+function die () {
+	echo $1;
+	exit 128;
+}
+
+test $# -eq 3 || usage "$0 <original> <new_workdir> <branch>";
+
+orig_git=$1;
+new_workdir=$2;
+branch=$3;
+
+# want to make sure that what is pointed to has a .git directory ...
+test -d ${orig_git}/.git || die "${original_git} is not a git repository!";
+
+# don't link to a workdir, link to the original repo the workdir is linked to
+if test -L ${orig_git}/.git/config
+then
+	orig_git=$(dirname $(dirname $(readlink -f gm/.git/config)));
+fi
+
+# make sure the the links use full paths
+orig_git=$(cd ${orig_git}; pwd);
+
+# create the workdir
+mkdir -p ${new_workdir}/.git || die "unable to create new dir ${new_workdir}!";
+
+# create the links to the original repo.  explictly exclude index, HEAD and
+# logs/HEAD from the list since they are purely related to the current working
+# directory, and should not be shared.
+for x in config refs logs/refs objects info hooks packed-refs remotes rr-cache
+do
+	case ${x} in
+	*/*)
+		mkdir -p $(dirname ${new_workdir}/.git/${x});
+		;;
+	esac
+	ln -s ${orig_git}/.git/${x} ${new_workdir}/.git/${x};
+done
+
+# now setup the workdir
+cd ${new_workdir};
+# create a fake HEAD, to stop checkout complaining
+echo "ref: refs/heads/master" > .git/HEAD;
+# now checkout the branch that was asked for
+git checkout -f ${branch};
+
+# vim: tabstop=8
+# vim: noexpandtab

-- 
1.5.0.5