Diagnostics for tracking down source of apparently corrupt block

insertion.

libethereum/EthereumPeer.cpp

@@ -403,19 +403,25 @@ bool EthereumPeer::interpret(unsigned _id, RLP const& _r)
 	}
 	case GetBlocksPacket:
 	{
-		clog(NetMessageSummary) << "GetBlocks (" << dec << _r.itemCount() << "entries)";
+		unsigned count = _r.itemCount();
+		clog(NetMessageSummary) << "GetBlocks (" << dec << count << "entries)";
 		// return the requested blocks.
 		bytes rlp;
 		unsigned n = 0;
-		for (unsigned i = 0; i < _r.itemCount() && i <= c_maxBlocks; ++i)
+		for (unsigned i = 0; i < min(count, c_maxBlocks); ++i)
 		{
-			auto b = host()->m_chain.block(_r[i].toHash<h256>());
-			if (b.size())
+			auto h = _r[i].toHash<h256>();
+			if (host()->m_chain.isKnown(h))
 			{
-				rlp += b;
+				rlp += host()->m_chain.block(_r[i].toHash<h256>());
 				++n;
 			}
 		}
+		if (count > 20 && n == 0)
+			clog(NetWarn) << "all" << count << "unknown blocks requested; peer on different chain?";
+		else
+			clog(NetMessageSummary) << n << "blocks known and returned;" << (min(count, c_maxBlocks) - n) << "blocks unknown;" << (c_maxBlocks > count ? c_maxBlocks - count : 0) << "blocks ignored";
+
 		addRating(0);
 		RLPStream s;
 		prep(s, BlocksPacket, n).appendRaw(rlp, n);

libethereum/State.cpp

@@ -276,6 +276,7 @@ bool State::sync(BlockChain const& _bc)
 
 bool State::sync(BlockChain const& _bc, h256 _block, BlockInfo const& _bi, ImportRequirements::value _ir)
 {
+	(void)_ir;
 	bool ret = false;
 	// BLOCK
 	BlockInfo bi = _bi ? _bi : _bc.info(_block);
@@ -315,6 +316,24 @@ bool State::sync(BlockChain const& _bc, h256 _block, BlockInfo const& _bi, Impor
 		// No change since last sync.
 		// Carry on as we were.
 	}
+	else
+	{
+		// New blocks available, or we've switched to a different branch. All change.
+		// Find most recent state dump and replay what's left.
+		// (Most recent state dump might end up being genesis.)
+
+		if (m_db.lookup(bi.stateRoot).empty())
+		{
+			cwarn << "Unable to sync to" << bi.hash().abridged() << "; state root" << bi.stateRoot.abridged() << "not found in database.";
+			cwarn << "Database corrupt: contains block without stateRoot:" << bi;
+			cwarn << "Bailing.";
+			exit(-1);
+		}
+		m_previousBlock = bi;
+		resetCurrent();
+		ret = true;
+	}
+#if ALLOW_REBUILD
 	else
 	{
 		// New blocks available, or we've switched to a different branch. All change.
@@ -352,6 +371,7 @@ bool State::sync(BlockChain const& _bc, h256 _block, BlockInfo const& _bi, Impor
 		resetCurrent();
 		ret = true;
 	}
+#endif
 	return ret;
 }
 
@@ -692,9 +712,9 @@ void State::cleanup(bool _fullCommit)
 		paranoia("immediately before database commit", true);
 
 		// Commit the new trie to disk.
-		cnote << "Commiting to disk...";
+		cnote << "Committing to disk: stateRoot" << m_currentBlock.stateRoot.abridged() << "=" << rootHash().abridged() << "=" << toHex(asBytes(m_db.lookup(rootHash())));
 		m_db.commit();
-		cnote << "Committed.";
+		cnote << "Committed: stateRoot" << m_currentBlock.stateRoot.abridged() << "=" << rootHash().abridged() << "=" << toHex(asBytes(m_db.lookup(rootHash())));
 
 		paranoia("immediately after database commit", true);
 		m_previousBlock = m_currentBlock;