Make "git tag" create both simple and signed tags

A simple tag is just a direct pointer to the object, while a signed tag
is a pointer to a "tag object" that has a pgp signature and points to
the object we tagged.

Use "git tag -s tagname" to create a signed tag.

The "-f" flag overwrites any previous tag of that name (useful if you
update a tag to point to a newer version for things like "latest" etc
tags that aren't necessarily static versions).

git-tag-script

@@ -2,25 +2,51 @@
 # Copyright (c) 2005 Linus Torvalds
 
 . git-sh-setup-script || die "Not a git archive"
+
+signed=
+force=
+while case "$#" in 0) break ;; esac
+do
+    case "$1" in
+    -s)
+	signed=1
+	;;
+    -f)
+	force=1
+	;;
+    *)
+	break
+	;;
+    esac
+    shift
+done
+
 name="$1"
 [ "$name" ] || die "I need a tag-name"
+[ -e "$GIT_DIR/refs/tags/$name" ] &&
+	[ "$force" ] || die "tag '$name' already exists"
+shift
 
-object=${2:-$(cat "$GIT_DIR"/HEAD)}
+object=$(git-rev-parse --verify --revs-only --default HEAD "$@") || exit 1
 type=$(git-cat-file -t $object) || exit 1
 tagger=$(git-var GIT_COMMITTER_IDENT) || exit 1
 
-( echo "#"
-  echo "# Write a tag message"
-  echo "#" ) > .editmsg
-${VISUAL:-${EDITOR:-vi}} .editmsg || exit
+if [ "$signed" ]; then
+    ( echo "#"
+      echo "# Write a tag message"
+      echo "#" ) > .editmsg
+    ${VISUAL:-${EDITOR:-vi}} .editmsg || exit
+
+    grep -v '^#' < .editmsg | git-stripspace > .tagmsg
 
-grep -v '^#' < .editmsg | git-stripspace > .tagmsg
+    [ -s .tagmsg ] || exit
 
-[ -s .tagmsg ] || exit
+    ( echo -e "object $object\ntype $type\ntag $name\ntagger $tagger\n"; cat .tagmsg ) > .tmp-tag
+    rm -f .tmp-tag.asc .tagmsg
+    gpg -bsa .tmp-tag && cat .tmp-tag.asc >> .tmp-tag
+    object=$(git-mktag < .tmp-tag)
+    rm -f .tmp-tag .tmp-tag.sig
+fi
 
-( echo -e "object $object\ntype $type\ntag $name\ntagger $tagger\n"; cat .tagmsg ) > .tmp-tag
-rm -f .tmp-tag.asc .tagmsg
-gpg -bsa .tmp-tag && cat .tmp-tag.asc >> .tmp-tag
 mkdir -p "$GIT_DIR/refs/tags"
-git-mktag < .tmp-tag > "$GIT_DIR/refs/tags/$name"
-#rm .tmp-tag .tmp-tag.sig
+echo $object > "$GIT_DIR/refs/tags/$name"