+git cat-file tag $tag_name >goodtag
+
+for h in object type tag; do
+ for how in missing dupe; do
+
+ case $how in
+ missing) perl -pe 's/^tag /wombat$&/ if 1..m/^$/' <goodtag >badtag ;;
+ dupe) perl -pe 'print if 1..m/^$/ and m/^'$h' /' <goodtag >badtag ;;
+ esac
+
+ rm -f badtag.asc
+ gpg --detach-sign --armor -u Senatus badtag
+ cat badtag.asc >>badtag
+
+ set +e
+ LC_MESSAGES=C git hash-object -w -t tag badtag >badtag.hash 2>badtag.err
+ rc=$?
+ set -e
+
+ if [ $rc = 128 ] && grep 'fatal: corrupt tag' badtag.err; then
+ continue
+ elif [ $rc != 0 ]; then
+ cat badtag.err
+ fail "could not make tag"
+ fi
+
+ read <badtag.hash badtag
+ git update-ref refs/tags/$tag_name $badtag
+
+ mustfail 'multiple headers '$h' in signed tag object' $push_spec
+ done
+done
+