Make tag_set_add() avoid adding tags that are already present.

diff --git a/lib/tag.c b/lib/tag.c
index 9cca57a055261be0614d4239103948c66ca73afb..ed198fcb698f8f2ab0404c5be7b2311ba24c34d5 100644 (file)
--- a/lib/tag.c
+++ b/lib/tag.c
@@ -82,7 +82,7 @@ tag_set_init(struct tag_set *set)
 void
 tag_set_add(struct tag_set *set, tag_type tag)
 {
-    if (tag) {
+    if (tag && (!tag_is_valid(tag) || !tag_set_intersects(set, tag))) {
         /* XXX We could do better by finding the set member to which we would
          * add the fewest number of 1-bits.  This would reduce the amount of
          * ambiguity, since e.g. three 1-bits match 3 * 2 / 2 = 3 unique tags