Merge pull request #4499 from ebfull/heartwood-testnet-hotfix

Heartwood testnet hotfix

src/chain.h

@@ -435,6 +435,12 @@ class CDiskBlockIndex : public CBlockIndex
 public:
     uint256 hashPrev;
 
+    // This is the serialized `nVersion` of the block index, which is only set
+    // after the (de)serialization routine is called. This should only be used
+    // in LoadBlockIndexGuts (which is the only place where we read block index
+    // objects from disk anyway).
+    int nClientVersion = 0;
+
     CDiskBlockIndex() {
         hashPrev = uint256();
     }
@@ -450,6 +456,7 @@ public:
         int nVersion = s.GetVersion();
         if (!(s.GetType() & SER_GETHASH))
             READWRITE(VARINT(nVersion));
+        nClientVersion = nVersion;
 
         READWRITE(VARINT(nHeight));
         READWRITE(VARINT(nStatus));

src/chainparams.cpp

@@ -322,6 +322,8 @@ public:
             uint256S("00367515ef2e781b8c9358b443b6329572599edd02c59e8af67db9785122f298");
         consensus.vUpgrades[Consensus::UPGRADE_HEARTWOOD].nProtocolVersion = 170010;
         consensus.vUpgrades[Consensus::UPGRADE_HEARTWOOD].nActivationHeight = 903800;
+        consensus.vUpgrades[Consensus::UPGRADE_HEARTWOOD].hashActivationBlock =
+            uint256S("05688d8a0e9ff7c04f6f05e6d695dc5ab43b9c4803342d77ae360b2b27d2468e");
 
         // On testnet we activate this rule 6 blocks after Blossom activation. From block 299188 and
         // prior to Blossom activation, the testnet minimum-difficulty threshold was 15 minutes (i.e.

src/coins.cpp

@@ -506,9 +506,17 @@ void CCoinsViewCache::PopHistoryNode(uint32_t epochId) {
 
     switch (historyCache.length) {
         case 0:
-            // Caller is not expected to pop from empty tree! Caller should
-            // switch to previous epoch and pop history from there.
-            throw std::runtime_error("popping history node from empty history");
+            // Caller is generally not expected to pop from empty tree! Caller
+            // should switch to previous epoch and pop history from there.
+
+            // If we are doing an expected rollback that changes the consensus
+            // branch ID for some upgrade (or introduces one that wasn't present
+            // at the equivalent height) this will occur because
+            // `SelectHistoryCache` selects the tree for the new consensus
+            // branch ID, not the one that existed on the chain being rolled
+            // back.
+            
+            // Sensible action is to truncate the history cache:
         case 1:
             // Just resetting tree to empty
             historyCache.Truncate(0);

src/main.cpp

@@ -4770,7 +4770,9 @@ bool RewindBlockIndex(const CChainParams& chainparams, bool& clearWitnessCaches)
             (networkID == "test" && nHeight == 252500 && *phashFirstInsufValidated ==
              uint256S("0018bd16a9c6f15795a754c498d2b2083ab78f14dae44a66a8d0e90ba8464d9c")) ||
             (networkID == "test" && nHeight == 584000 && *phashFirstInsufValidated ==
-             uint256S("002e1d6daf4ab7b296e7df839dc1bee9d615583bb4bc34b1926ce78307532852"));
+             uint256S("002e1d6daf4ab7b296e7df839dc1bee9d615583bb4bc34b1926ce78307532852")) ||
+            (networkID == "test" && nHeight == 903800 && *phashFirstInsufValidated ==
+             uint256S("0044f3c696a242220ed608c70beba5aa804f1cfb8a20e32186727d1bec5dfa1e"));
 
         clearWitnessCaches = (rewindLength > MAX_REORG_LENGTH && intendedRewind);
 

src/txdb.cpp

@@ -566,11 +566,15 @@ bool CBlockTreeDB::LoadBlockIndexGuts(
                     return error("LoadBlockIndex(): CheckProofOfWork failed: %s", pindexNew->ToString());
 
                 // ZIP 221 consistency checks
-                if (chainParams.GetConsensus().NetworkUpgradeActive(pindexNew->nHeight, Consensus::UPGRADE_HEARTWOOD)) {
+                // We assume block index objects on disk that are not at least
+                // CHAIN_HISTORY_ROOT_VERSION were created by nodes that were
+                // not Heartwood aware.
+                if (diskindex.nClientVersion >= CHAIN_HISTORY_ROOT_VERSION &&
+                    chainParams.GetConsensus().NetworkUpgradeActive(pindexNew->nHeight, Consensus::UPGRADE_HEARTWOOD)) {
                     if (pindexNew->hashLightClientRoot != pindexNew->hashChainHistoryRoot) {
                         return error(
-                            "LoadBlockIndex(): block index inconsistency detected (hashLightClientRoot != hashChainHistoryRoot): %s",
-                            pindexNew->ToString());
+                            "LoadBlockIndex(): block index inconsistency detected (hashLightClientRoot %s != hashChainHistoryRoot %s): %s",
+                            pindexNew->hashLightClientRoot.ToString(), pindexNew->hashChainHistoryRoot.ToString(), pindexNew->ToString());
                     }
                 } else {
                     if (pindexNew->hashLightClientRoot != pindexNew->hashFinalSaplingRoot) {