Merge #15283: log: Fix UB with bench on genesis block

ec30a79f1c Fix UB with bench on genesis block (Gregory Sanders)

Pull request description:

  During the loading of the genesis block, the bench print lines in ConnectTip divide by zero due to early return in ConnectBlock.

ACKs for top commit:
  practicalswift:
    ACK ec30a79f1c
  sipa:
    utACK ec30a79f1c
  promag:
    ACK ec30a79, `nBlocksTotal` is only used in logging.

Tree-SHA512: b3bdbb58d10d002a2293d7f99196b227ed9f4ca8c6cd08981e95cc964be47efed98b91fad276ee6da5cf7e6684610998ace7ce9bace172dd6c51c386d985b83c

src/validation.cpp

@@ -1927,6 +1927,8 @@ bool CChainState::ConnectBlock(const CBlock& block, BlockValidationState& state,
     uint256 hashPrevBlock = pindex->pprev == nullptr ? uint256() : pindex->pprev->GetBlockHash();
     assert(hashPrevBlock == view.GetBestBlock());
 
+    nBlocksTotal++;
+
     // Special case for the genesis block, skipping connection of its transactions
     // (its coinbase is unspendable)
     if (block.GetHash() == chainparams.GetConsensus().hashGenesisBlock) {
@@ -1935,8 +1937,6 @@ bool CChainState::ConnectBlock(const CBlock& block, BlockValidationState& state,
         return true;
     }
 
-    nBlocksTotal++;
-
     bool fScriptChecks = true;
     if (!hashAssumeValid.IsNull()) {
         // We've been configured with the hash of a block which has been externally verified to have a valid history.
@@ -2598,6 +2598,7 @@ bool CChainState::ConnectTip(BlockValidationState& state, const CChainParams& ch
             return error("%s: ConnectBlock %s failed, %s", __func__, pindexNew->GetBlockHash().ToString(), state.ToString());
         }
         nTime3 = GetTimeMicros(); nTimeConnectTotal += nTime3 - nTime2;
+        assert(nBlocksTotal > 0);
         LogPrint(BCLog::BENCH, "  - Connect total: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime3 - nTime2) * MILLI, nTimeConnectTotal * MICRO, nTimeConnectTotal * MILLI / nBlocksTotal);
         bool flushed = view.Flush();
         assert(flushed);