From 6c48642ff9cd7f422c7a85bcdaac9e12da835a1e Mon Sep 17 00:00:00 2001
From: Jae Kwon <jkwon.work@gmail.com>
Date: Mon, 19 Jan 2015 14:08:53 -0800
Subject: [PATCH] don't cache the block/header hashes. fixes a cache
 invalidation bug

---
 block/block.go     | 47 ++++++++++++++++++----------------------------
 consensus/state.go |  6 +++++-
 2 files changed, 23 insertions(+), 30 deletions(-)

diff --git a/block/block.go b/block/block.go
index 30ef0b5bf..79f99ef68 100644
--- a/block/block.go
+++ b/block/block.go
@@ -19,9 +19,6 @@ type Block struct {
 	*Header
 	*Validation
 	*Data
-
-	// Volatile
-	hash []byte
 }
 
 // Basic validation that doesn't involve state data.
@@ -57,16 +54,13 @@ func (b *Block) ValidateBasic(lastBlockHeight uint, lastBlockHash []byte,
 }
 
 func (b *Block) Hash() []byte {
-	if b.hash == nil {
-		hashes := [][]byte{
-			b.Header.Hash(),
-			b.Validation.Hash(),
-			b.Data.Hash(),
-		}
-		// Merkle hash from sub-hashes.
-		b.hash = merkle.HashFromHashes(hashes)
+	hashes := [][]byte{
+		b.Header.Hash(),
+		b.Validation.Hash(),
+		b.Data.Hash(),
 	}
-	return b.hash
+	// Merkle hash from sub-hashes.
+	return merkle.HashFromHashes(hashes)
 }
 
 // Convenience.
@@ -95,7 +89,7 @@ func (b *Block) StringIndented(indent string) string {
 		indent, b.Header.StringIndented(indent+"  "),
 		indent, b.Validation.StringIndented(indent+"  "),
 		indent, b.Data.StringIndented(indent+"  "),
-		indent, b.hash)
+		indent, b.Hash())
 }
 
 func (b *Block) StringShort() string {
@@ -117,25 +111,20 @@ type Header struct {
 	LastBlockHash  []byte
 	LastBlockParts PartSetHeader
 	StateHash      []byte
-
-	// Volatile
-	hash []byte
 }
 
 func (h *Header) Hash() []byte {
-	if h.hash == nil {
-		buf := new(bytes.Buffer)
-		hasher, n, err := sha256.New(), new(int64), new(error)
-		binary.WriteBinary(h, buf, n, err)
-		if *err != nil {
-			panic(err)
-		}
-		log.Debug("Hashing", "bytes", buf.Bytes())
-		hasher.Write(buf.Bytes())
-		h.hash = hasher.Sum(nil)
-		log.Debug("Hashing got", "hash", h.hash)
+	buf := new(bytes.Buffer)
+	hasher, n, err := sha256.New(), new(int64), new(error)
+	binary.WriteBinary(h, buf, n, err)
+	if *err != nil {
+		panic(err)
 	}
-	return h.hash
+	log.Debug("Hashing", "bytes", buf.Bytes())
+	hasher.Write(buf.Bytes())
+	hash := hasher.Sum(nil)
+	log.Debug("Hashing got", "hash", hash)
+	return hash
 }
 
 func (h *Header) StringIndented(indent string) string {
@@ -157,7 +146,7 @@ func (h *Header) StringIndented(indent string) string {
 		indent, h.LastBlockHash,
 		indent, h.LastBlockParts,
 		indent, h.StateHash,
-		indent, h.hash)
+		indent, h.Hash())
 }
 
 //-----------------------------------------------------------------------------
diff --git a/consensus/state.go b/consensus/state.go
index b7307407e..2d992918e 100644
--- a/consensus/state.go
+++ b/consensus/state.go
@@ -635,7 +635,11 @@ func (cs *ConsensusState) RunActionPropose(height uint, round uint) {
 		}
 
 		// Set the blk.Header.StateHash.
-		cs.state.SetBlockStateHash(block)
+		err := cs.state.SetBlockStateHash(block)
+		if err != nil {
+			log.Error("Error setting state hash", "error", err)
+			return
+		}
 
 		blockParts = blk.NewPartSetFromData(binary.BinaryBytes(block))
 		pol = cs.LockedPOL // If exists, is a PoUnlock.