diff --git a/lib/zclient.c b/lib/zclient.c
index bba06ee..e76652d 100644
--- a/lib/zclient.c
+++ b/lib/zclient.c
@@ -321,6 +321,8 @@
         {
           stream_putc (s, 1);
           stream_putc (s, ZEBRA_NEXTHOP_BLACKHOLE);
+	  /* XXX assert(api->nexthop_num == 0); */
+	  /* XXX assert(api->ifindex_num == 0); */
         }
       else
         stream_putc (s, api->nexthop_num + api->ifindex_num);
@@ -381,6 +383,8 @@
         {
           stream_putc (s, 1);
           stream_putc (s, ZEBRA_NEXTHOP_BLACKHOLE);
+	  /* XXX assert(api->nexthop_num == 0); */
+	  /* XXX assert(api->ifindex_num == 0); */
         }
       else
         stream_putc (s, api->nexthop_num + api->ifindex_num);