add a few checks where it seems appropriate

src/blockchain_db/lmdb/db_lmdb.cpp

@@ -707,7 +707,7 @@ uint64_t BlockchainLMDB::get_estimated_batch_size(uint64_t batch_num_blocks, uin
       ++num_blocks_used;
     }
     if (my_rtxn) block_rtxn_stop();
-    avg_block_size = total_block_size / num_blocks_used;
+    avg_block_size = total_block_size / (num_blocks_used ? num_blocks_used : 1);
     MDEBUG("average block size across recent " << num_blocks_used << " blocks: " << avg_block_size);
   }
 estim:

src/blockchain_utilities/blockchain_blackball.cpp

@@ -637,6 +637,7 @@ static void inc_per_amount_outputs(MDB_txn *txn, uint64_t amount, uint64_t total
   v.mv_size = 2 * sizeof(uint64_t);
   v.mv_data = (void*)data;
   dbr = mdb_cursor_put(cur, &k, &v, 0);
+  CHECK_AND_ASSERT_THROW_MES(!dbr, "Failed to write record for per amount outputs: " + std::string(mdb_strerror(dbr)));
   mdb_cursor_close(cur);
 }
 

src/cryptonote_core/cryptonote_core.cpp

@@ -447,6 +447,7 @@ namespace cryptonote
       m_nettype = FAKECHAIN;
     }
     bool r = handle_command_line(vm);
+    CHECK_AND_ASSERT_MES(r, false, "Failed to handle command line");
 
     std::string db_type = command_line::get_arg(vm, cryptonote::arg_db_type);
     std::string db_sync_mode = command_line::get_arg(vm, cryptonote::arg_db_sync_mode);
@@ -634,6 +635,7 @@ namespace cryptonote
     };
     const difficulty_type fixed_difficulty = command_line::get_arg(vm, arg_fixed_difficulty);
     r = m_blockchain_storage.init(db.release(), m_nettype, m_offline, regtest ? &regtest_test_options : test_options, fixed_difficulty, get_checkpoints);
+    CHECK_AND_ASSERT_MES(r, false, "Failed to initialize blockchain storage");
 
     r = m_mempool.init(max_txpool_weight);
     CHECK_AND_ASSERT_MES(r, false, "Failed to initialize memory pool");

src/rpc/core_rpc_server.cpp

@@ -1510,7 +1510,7 @@ namespace cryptonote
       ok = ok && getheight_res.status == CORE_RPC_STATUS_OK;
 
       m_should_use_bootstrap_daemon = ok && top_height + 10 < getheight_res.height;
-      MINFO((m_should_use_bootstrap_daemon ? "Using" : "Not using") << " the bootstrap daemon (our height: " << top_height << ", bootstrap daemon's height: " << getheight_res.height << ")");
+      MINFO((m_should_use_bootstrap_daemon ? "Using" : "Not using") << " the bootstrap daemon (our height: " << top_height << ", bootstrap daemon's height: " << (ok ? getheight_res.height : 0) << ")");
     }
     if (!m_should_use_bootstrap_daemon)
       return false;