[PATCH 1/4] contrib/subtree: Teach push to abort if split fails

[Paul Campbell <pcampbell@kemitix.net>]

From: Michael Hart <michael@adslot.com>

If the subtree split fails it doesn't return the SHA that should be
pushed to the other repository.

Added a check to ensure that split succeeds before trying to push
and display an error message.

Signed-off-by: Paul Campbell <pcampbell@kemitix.net>
---
 contrib/subtree/git-subtree.sh | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/contrib/subtree/git-subtree.sh b/contrib/subtree/git-subtree.sh
index 8a23f58..c68cc6f 100755
--- a/contrib/subtree/git-subtree.sh
+++ b/contrib/subtree/git-subtree.sh
@@ -715,7 +715,12 @@ cmd_push()
 	    repository=$1
 	    refspec=$2
 	    echo "git push using: " $repository $refspec
-	    git push $repository $(git subtree split --prefix=$prefix):refs/heads/$refspec
+	    rev=$(git subtree split --prefix=$prefix)
+	    if [ -n "$rev" ]; then
+		git push $repository $rev:refs/heads/$refspec
+	    else
+		die "Couldn't push, 'git subtree split' failed."
+	    fi
 	else
 	    die "'$dir' must already exist. Try 'git subtree add'."
 	fi
-- 
1.8.2