object=$(git-rev-parse --verify --default HEAD "$@") || exit 1
type=$(git-cat-file -t $object) || exit 1
tagger=$(git-var GIT_COMMITTER_IDENT) || exit 1
-: ${username:=$(expr "$tagger" : '\(.*>\)')}
+: ${username:=$(expr "z$tagger" : 'z\(.*>\)')}
trap 'rm -f "$GIT_DIR"/TAG_TMP* "$GIT_DIR"/TAG_FINALMSG "$GIT_DIR"/TAG_EDITMSG' 0