thodg/libgit2

diff --git a/src/libgit2/tag.c b/src/libgit2/tag.c
index 3d8f8bf..792155a 100644
--- a/src/libgit2/tag.c
+++ b/src/libgit2/tag.c
@@ -554,6 +554,8 @@ int git_tag_name_is_valid(int *valid, const char *name)
 
 	GIT_ASSERT(valid);
 
+	*valid = 0;
+
 	if (!name || !tag_name_is_valid(name))
 		goto done;