blockchain: fix m_long_term_block_weight_height initialization

Also check return of that function, it can now return error

src/cryptonote_core/blockchain.cpp

@@ -504,10 +504,10 @@ bool Blockchain::init(BlockchainDB* db, const network_type nettype, bool offline
   {
     m_long_term_block_weights.push_front(db_height - 1 - m_long_term_block_weights.size());
   }
-  if (!m_long_term_block_weights.empty())
-    m_long_term_block_weights.pop_back();
+  m_long_term_block_weights_height = db_height;
 
-  update_next_cumulative_weight_limit();
+  if (!update_next_cumulative_weight_limit())
+    return false;
   return true;
 }
 //------------------------------------------------------------------
@@ -656,7 +656,8 @@ block Blockchain::pop_block_from_blockchain()
   m_blocks_txs_check.clear();
   m_check_txin_table.clear();
 
-  update_next_cumulative_weight_limit();
+  CHECK_AND_ASSERT_THROW_MES(update_next_cumulative_weight_limit(), "Error updating next cumulative weight limit");
+
   m_tx_pool.on_blockchain_dec(m_db->height()-1, get_tail_id());
   invalidate_block_template_cache();
 
@@ -677,7 +678,8 @@ bool Blockchain::reset_and_set_genesis_block(const block& b)
 
   block_verification_context bvc = boost::value_initialized<block_verification_context>();
   add_new_block(b, bvc);
-  update_next_cumulative_weight_limit();
+  if (!update_next_cumulative_weight_limit())
+    return false;
   return bvc.m_added_to_main_chain && !bvc.m_verifivation_failed;
 }
 //------------------------------------------------------------------
@@ -3595,7 +3597,12 @@ leave:
   TIME_MEASURE_FINISH(addblock);
 
   // do this after updating the hard fork state since the weight limit may change due to fork
-  update_next_cumulative_weight_limit();
+  if (!update_next_cumulative_weight_limit())
+  {
+    MERROR("Failed to update next cumulative weight limit");
+    pop_block_from_blockchain();
+    return false;
+  }
 
   MINFO("+++++ BLOCK SUCCESSFULLY ADDED" << std::endl << "id:\t" << id << std::endl << "PoW:\t" << proof_of_work << std::endl << "HEIGHT " << new_height-1 << ", difficulty:\t" << current_diffic << std::endl << "block reward: " << print_money(fee_summary + base_reward) << "(" << print_money(base_reward) << " + " << print_money(fee_summary) << "), coinbase_weight: " << coinbase_weight << ", cumulative weight: " << cumulative_block_weight << ", " << block_processing_time << "(" << target_calculating_time << "/" << longhash_calculating_time << ")ms");
   if(m_show_time_stats)