InternalLevel: appending an empty level is a no-op

The existing reconstruction logic will occasionally attempt to append an
empty level to another empty level, for some reason. While the underlying
cause of this needs to be looked into, this special case should prevent
shard constructors being called with a shard count of 0 under tiering,
reducing the error handling overhead of shard code.

1 files changed, 7 insertions, 0 deletions

diff --git a/include/framework/structure/InternalLevel.h b/include/framework/structure/InternalLevel.h
index e70ed76..ee85cb3 100644
--- a/include/framework/structure/InternalLevel.h
+++ b/include/framework/structure/InternalLevel.h
@@ -68,6 +68,13 @@ public:
      * No changes are made to the level provided as an argument.
      */
     void append_level(InternalLevel* level) {
+        // FIXME: that this is happening probably means that
+        // something is going terribly wrong earlier in the
+        // reconstruction logic.
+        if (level->get_shard_count() == 0) {
+            return;
+        }
+
         Shard *shards[level->m_shard_cnt];
         for (size_t i=0; i<level->m_shard_cnt; i++) {
             shards[i] = level->m_shards[i].get();