From 5d65fe312e22594b7fec7349945fb0072987716b Mon Sep 17 00:00:00 2001
From: Rob Mayoff <mayoff@dqd.com>
Date: Fri, 13 Nov 2015 11:25:49 -0600
Subject: [PATCH] contrib/subtree: unwrap tag refs

If a subtree was added using a tag ref, the tag ref is stored in
the subtree commit message instead of the underlying commit's ref.
To split or push subsequent changes to the subtree, the subtree
command needs to unwrap the tag ref.  This patch makes it do so.

The problem was described in a message to the mailing list from
Junio C Hamano dated 29 Apr 2014, with the subject "Re: git subtree
issue in more recent versions". The archived message can be found
at <http://comments.gmane.org/gmane.comp.version-control.git/247503>.

Signed-off-by: Rob Mayoff <mayoff@dqd.com>
Signed-off-by: Jeff King <peff@peff.net>
---
 contrib/subtree/git-subtree.sh | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/contrib/subtree/git-subtree.sh b/contrib/subtree/git-subtree.sh
index 9f06571851..5ed0ea5e94 100755
--- a/contrib/subtree/git-subtree.sh
+++ b/contrib/subtree/git-subtree.sh
@@ -245,7 +245,10 @@ find_latest_squash()
 		case "$a" in
 			START) sq="$b" ;;
 			git-subtree-mainline:) main="$b" ;;
-			git-subtree-split:) sub="$b" ;;
+			git-subtree-split:)
+				sub="$(git rev-parse "$b^0")" ||
+				    die "could not rev-parse split hash $b from commit $sq"
+				;;
 			END)
 				if [ -n "$sub" ]; then
 					if [ -n "$main" ]; then
@@ -278,7 +281,10 @@ find_existing_splits()
 		case "$a" in
 			START) sq="$b" ;;
 			git-subtree-mainline:) main="$b" ;;
-			git-subtree-split:) sub="$b" ;;
+			git-subtree-split:)
+				sub="$(git rev-parse "$b^0")" ||
+				    die "could not rev-parse split hash $b from commit $sq"
+				;;
 			END)
 				debug "  Main is: '$main'"
 				if [ -z "$main" -a -n "$sub" ]; then