From 71baad59dfa202f0a6a93fe572908dd83dcefd06 Mon Sep 17 00:00:00 2001
From: Ethan Buchman <ethan@coinculture.info>
Date: Tue, 11 Oct 2016 16:06:46 -0400
Subject: [PATCH] replay: ensure cs.height and wal.height match

---
 blockchain/reactor.go |  2 +-
 consensus/replay.go   | 18 +++++++++++++++---
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/blockchain/reactor.go b/blockchain/reactor.go
index 9a68ad88..5946e77d 100644
--- a/blockchain/reactor.go
+++ b/blockchain/reactor.go
@@ -129,7 +129,7 @@ func (bcR *BlockchainReactor) Receive(chID byte, src *p2p.Peer, msgBytes []byte)
 		return
 	}
 
-	log.Notice("Receive", "src", src, "chID", chID, "msg", msg)
+	log.Info("Receive", "src", src, "chID", chID, "msg", msg)
 
 	switch msg := msg.(type) {
 	case *bcBlockRequestMessage:
diff --git a/consensus/replay.go b/consensus/replay.go
index c77d0558..afdbcf9f 100644
--- a/consensus/replay.go
+++ b/consensus/replay.go
@@ -77,7 +77,7 @@ func (cs *ConsensusState) readReplayMessage(msgBytes []byte, newStepCh chan inte
 
 // replay only those messages since the last block.
 // timeoutRoutine should run concurrently to read off tickChan
-func (cs *ConsensusState) catchupReplay(height int) error {
+func (cs *ConsensusState) catchupReplay(csHeight int) error {
 	if !cs.wal.Exists() {
 		return nil
 	}
@@ -88,6 +88,7 @@ func (cs *ConsensusState) catchupReplay(height int) error {
 
 	// starting from end of file,
 	// read messages until a new height is found
+	var walHeight int
 	nLines, err := cs.wal.SeekFromEnd(func(lineBytes []byte) bool {
 		var err error
 		var msg ConsensusLogMessage
@@ -96,8 +97,8 @@ func (cs *ConsensusState) catchupReplay(height int) error {
 			panic(Fmt("Failed to read cs_msg_log json: %v", err))
 		}
 		m, ok := msg.Msg.(types.EventDataRoundState)
+		walHeight = m.Height
 		if ok && m.Step == RoundStepNewHeight.String() {
-			// TODO: ensure the height matches
 			return true
 		}
 		return false
@@ -107,12 +108,23 @@ func (cs *ConsensusState) catchupReplay(height int) error {
 		return err
 	}
 
+	// ensure the height matches
+	if walHeight != csHeight {
+		var err error
+		if walHeight > csHeight {
+			err = errors.New(Fmt("WAL height (%d) exceeds cs height (%d). Is your cs.state corrupted?", walHeight, csHeight))
+		} else {
+			log.Notice("Replay: nothing to do", "cs.height", csHeight, "wal.height", walHeight)
+		}
+		return err
+	}
+
 	var beginning bool // if we had to go back to the beginning
 	if c, _ := cs.wal.fp.Seek(0, 1); c == 0 {
 		beginning = true
 	}
 
-	log.Notice("Catchup by replaying consensus messages", "n", nLines)
+	log.Notice("Catchup by replaying consensus messages", "n", nLines, "height", walHeight)
 
 	// now we can replay the latest nLines on consensus state
 	// note we can't use scan because we've already been reading from the file