Use git-update-ref in scripts.

This uses the git-update-ref command in scripts for safer updates.
Also places where we used to read HEAD ref by using "cat" were fixed
to use git-rev-parse.  This will matter when we start using symbolic
references.

Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 5 insertions, 4 deletions

diff --git a/git-merge.sh b/git-merge.sh
index 5890c7b1c0..29e86c6953 100755
--- a/git-merge.sh
+++ b/git-merge.sh
@@ -116,8 +116,9 @@ case "$#,$common" in
 	# Again the most common case of merging one remote.
 	echo "Updating from $head to $1."
 	git-update-index --refresh 2>/dev/null
-	git-read-tree -u -m $head "$1" || exit 1
-	git-rev-parse --verify "$1^0" > "$GIT_DIR/HEAD"
+	git-read-tree -u -m $head "$1" &&
+	new_head=$(git-rev-parse --verify "$1^0") &&
+	git-update-ref HEAD "$new_head" "$head" || exit 1
 	summary "$1"
 	dropsave
 	exit 0
@@ -215,9 +216,9 @@ then
     do
         parents="$parents -p $remote"
     done
-    result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents)
+    result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
     echo "Committed merge $result_commit, made by $wt_strategy."
-    echo $result_commit >"$GIT_DIR/HEAD"
+    git-update-ref HEAD $result_commit $head
     summary $result_commit
     dropsave
     exit 0