anchor.diff:  
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   
  --spec build_recon_struct(Method, DB_Chunk) -> Recon_Struct when
  -      is_subtype(Method,       method()),
  -      is_subtype(DB_Chunk,     {intervals:interval(), db_chunk_enc()}),
  -      is_subtype(Recon_Struct, sync_struct()).
  +-spec build_recon_struct(method(), {intervals:non_empty_interval(), db_chunk_enc()})
  +        -> sync_struct().
   build_recon_struct(bloom, {I, DBItems}) ->
  +    ?ASSERT(not intervals:is_empty(I)),
       Fpr = get_bloom_fpr(),
       ElementNum = length(DBItems),
       HFCount = bloom:calc_HF_numEx(ElementNum, Fpr),
       BF = ?REP_BLOOM:new(ElementNum, Fpr, ?REP_HFS:new(HFCount), DBItems),
       #bloom_recon_struct{ interval = I, bloom = BF };
   build_recon_struct(merkle_tree, {I, DBItems}) ->
  +    ?ASSERT(not intervals:is_empty(I)),
       merkle_tree:new(I, DBItems, [{branch_factor, get_merkle_branch_factor()},
                                    {bucket_size, get_merkle_bucket_size()}]);
   build_recon_struct(art, {I, DBItems}) ->
  +    ?ASSERT(not intervals:is_empty(I)),
       Branch = get_merkle_branch_factor(),
       BucketSize = merkle_tree:get_opt_bucket_size(length(DBItems), Branch, 1),
       Tree = merkle_tree:new(I, DBItems, [{branch_factor, Branch},
  
positive.code: 
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  -spec build_struct(DBList::db_chunk_enc(), DestI::I, RestI::I, state()) -> state() | kill
            when is_subtype(I, intervals:interval()).
  build_struct(DBList, DestI, RestI,
               State = #rr_recon_state{method = RMethod, struct = Params,
                                       initiator = Initiator, stats = Stats,
                                       dhtNodePid = DhtNodePid, stage = Stage}) ->
      {BuildTime, SyncStruct} =
          case merkle_tree:is_merkle_tree(Params) of
              true ->
  
negative.code: %% art recon
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  -spec art_recon(MyTree::merkle_tree:merkle_tree(), art:art(), state())
          -> rr_recon_stats:stats().
  art_recon(Tree, Art, #rr_recon_state{ dest_rr_pid = DestPid,
                                        ownerPid = OwnerL,
                                        stats = Stats }) ->
  