From 1834d95b432d990ecd36708120663870fa60060a Mon Sep 17 00:00:00 2001
From: Brannon King <countprimes@gmail.com>
Date: Thu, 26 Aug 2021 15:07:42 -0400
Subject: [PATCH] rollback on hash mismatch

---
 blockchain/chain.go     |  4 ++--
 blockchain/claimtrie.go | 13 ++++++-------
 2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/blockchain/chain.go b/blockchain/chain.go
index 128101f8..1511b770 100644
--- a/blockchain/chain.go
+++ b/blockchain/chain.go
@@ -586,7 +586,7 @@ func (b *BlockChain) connectBlock(node *blockNode, block *btcutil.Block,
 
 	// Handle LBRY Claim Scripts
 	if b.claimTrie != nil {
-		if err := b.ParseClaimScripts(block, node, view, false, current); err != nil {
+		if err := b.ParseClaimScripts(block, node, view, current); err != nil {
 			return ruleError(ErrBadClaimTrie, err.Error())
 		}
 	}
@@ -1881,7 +1881,7 @@ func rebuildMissingClaimTrieData(b *BlockChain, done <-chan struct{}) error {
 		}
 
 		if h >= b.claimTrie.Height() {
-			err = b.ParseClaimScripts(block, n, view, true, false)
+			err = b.ParseClaimScripts(block, n, view, false)
 			if err != nil {
 				return err
 			}
diff --git a/blockchain/claimtrie.go b/blockchain/claimtrie.go
index 8b9b449e..1032860d 100644
--- a/blockchain/claimtrie.go
+++ b/blockchain/claimtrie.go
@@ -20,7 +20,7 @@ func (b *BlockChain) SetClaimtrieHeader(block *btcutil.Block, view *UtxoViewpoin
 	b.chainLock.Lock()
 	defer b.chainLock.Unlock()
 
-	err := b.ParseClaimScripts(block, nil, view, false, false)
+	err := b.ParseClaimScripts(block, nil, view, false)
 	if err != nil {
 		return errors.Wrapf(err, "in parse claim scripts")
 	}
@@ -31,8 +31,7 @@ func (b *BlockChain) SetClaimtrieHeader(block *btcutil.Block, view *UtxoViewpoin
 	return errors.Wrapf(err, "in reset height")
 }
 
-func (b *BlockChain) ParseClaimScripts(block *btcutil.Block, bn *blockNode, view *UtxoViewpoint,
-	failOnHashMiss bool, shouldFlush bool) error {
+func (b *BlockChain) ParseClaimScripts(block *btcutil.Block, bn *blockNode, view *UtxoViewpoint, shouldFlush bool) error {
 	ht := block.Height()
 
 	for _, tx := range block.Transactions() {
@@ -56,10 +55,10 @@ func (b *BlockChain) ParseClaimScripts(block *btcutil.Block, bn *blockNode, view
 
 	hash := b.claimTrie.MerkleHash()
 	if bn != nil && bn.claimTrie != *hash {
-		if failOnHashMiss {
-			return errors.Errorf("height: %d, ct.MerkleHash: %s != node.ClaimTrie: %s", ht, *hash, bn.claimTrie)
-		}
-		node.LogOnce(fmt.Sprintf("\n\nHeight: %d, ct.MerkleHash: %s != node.ClaimTrie: %s, Error: %s", ht, *hash, bn.claimTrie, err))
+		// undo our AppendBlock call as we've decided that our interpretation of the block data is incorrect,
+		// or that the person who made the block assembled the pieces incorrectly.
+		_ = b.claimTrie.ResetHeight(b.claimTrie.Height() - 1)
+		return errors.Errorf("height: %d, computed hash: %s != header's ClaimTrie: %s", ht, *hash, bn.claimTrie)
 	}
 	return nil
 }