From f5d0794756a60942589064ae5f72591796495173 Mon Sep 17 00:00:00 2001
From: Jae Kwon <jkwon.work@gmail.com>
Date: Mon, 20 Oct 2014 19:02:10 -0700
Subject: [PATCH] RoundAction // FinalizeCommit // LastCommits

---
 blocks/block.go             |  13 --
 blocks/block_test.go        |   4 +-
 blocks/vote.go              |   8 +-
 consensus/consensus.go      | 292 ++++++++++++++++++------------------
 consensus/pol.go            |   4 +-
 consensus/pol_test.go       |   6 +-
 consensus/priv_validator.go |   6 +-
 consensus/state.go          | 113 ++++++++++----
 consensus/state_test.go     |  73 ++++++++-
 consensus/test.go           |   2 +-
 consensus/vote_set.go       |  45 +++++-
 consensus/vote_set_test.go  |  24 +--
 mempool/mempool.go          |  21 +--
 state/state.go              |  14 +-
 14 files changed, 382 insertions(+), 243 deletions(-)

diff --git a/blocks/block.go b/blocks/block.go
index 216ba124c..3166779d5 100644
--- a/blocks/block.go
+++ b/blocks/block.go
@@ -85,19 +85,6 @@ func (b *Block) HashesTo(hash []byte) bool {
 	return bytes.Equal(b.Hash(), hash)
 }
 
-// Makes an empty next block.
-func (b *Block) MakeNextBlock() *Block {
-	return &Block{
-		Header: Header{
-			Network:       b.Header.Network,
-			Height:        b.Header.Height + 1,
-			Time:          time.Now(),
-			LastBlockHash: b.Hash(),
-			StateHash:     nil,
-		},
-	}
-}
-
 func (b *Block) String() string {
 	return b.StringWithIndent("")
 }
diff --git a/blocks/block_test.go b/blocks/block_test.go
index 474fa9f8a..bd317cb6d 100644
--- a/blocks/block_test.go
+++ b/blocks/block_test.go
@@ -40,14 +40,14 @@ func randBlock() *Block {
 		VoteA: Vote{
 			Height:    RandUInt32Exp(),
 			Round:     RandUInt16Exp(),
-			Type:      VoteTypeBare,
+			Type:      VoteTypePrevote,
 			BlockHash: RandBytes(32),
 			Signature: randSig(),
 		},
 		VoteB: Vote{
 			Height:    RandUInt32Exp(),
 			Round:     RandUInt16Exp(),
-			Type:      VoteTypeBare,
+			Type:      VoteTypePrevote,
 			BlockHash: RandBytes(32),
 			Signature: randSig(),
 		},
diff --git a/blocks/vote.go b/blocks/vote.go
index 94ee854af..eea61ff74 100644
--- a/blocks/vote.go
+++ b/blocks/vote.go
@@ -9,7 +9,7 @@ import (
 )
 
 const (
-	VoteTypeBare      = byte(0x00)
+	VoteTypePrevote   = byte(0x00)
 	VoteTypePrecommit = byte(0x01)
 	VoteTypeCommit    = byte(0x02)
 )
@@ -22,7 +22,7 @@ var (
 	ErrVoteConflictingSignature = errors.New("Conflicting round vote signature")
 )
 
-// Represents a bare, precommit, or commit vote for proposals.
+// Represents a prevote, precommit, or commit vote for proposals.
 type Vote struct {
 	Height    uint32
 	Round     uint16
@@ -64,12 +64,12 @@ func (v *Vote) String() string {
 		blockHash = make([]byte, 6) // for printing
 	}
 	switch v.Type {
-	case VoteTypeBare:
+	case VoteTypePrevote:
 		return fmt.Sprintf("Vote{%v/%v:%X:%v}", v.Height, v.Round, blockHash, v.SignerId)
 	case VoteTypePrecommit:
 		return fmt.Sprintf("Precommit{%v/%v:%X:%v}", v.Height, v.Round, blockHash, v.SignerId)
 	case VoteTypeCommit:
-		return fmt.Sprintf("Commit{%v/%v:%X:%v}", v.Height, v.Round, v.BlockHash[:6], v.SignerId)
+		return fmt.Sprintf("Commit{%v/%v:%X:%v}", v.Height, v.Round, blockHash, v.SignerId)
 	default:
 		panic("Unknown vote type")
 	}
diff --git a/consensus/consensus.go b/consensus/consensus.go
index 1240c80c0..51c285f9b 100644
--- a/consensus/consensus.go
+++ b/consensus/consensus.go
@@ -30,10 +30,10 @@ const (
 
 	roundDuration0         = 60 * time.Second   // The first round is 60 seconds long.
 	roundDurationDelta     = 15 * time.Second   // Each successive round lasts 15 seconds longer.
-	roundDeadlineBare      = float64(1.0 / 3.0) // When the bare vote is due.
+	roundDeadlinePrevote   = float64(1.0 / 3.0) // When the prevote is due.
 	roundDeadlinePrecommit = float64(2.0 / 3.0) // When the precommit vote is due.
 
-	newBlockWaitDuration    = roundDuration0 / 3    // The time to wait between commitTime and startTime of next consensus rounds.
+	finalizeDuration        = roundDuration0 / 3    // The time to wait between commitTime and startTime of next consensus rounds.
 	peerGossipSleepDuration = 50 * time.Millisecond // Time to sleep if there's nothing to send.
 	hasVotesThreshold       = 50                    // After this many new votes we'll send a HasVotesMessage.
 )
@@ -122,7 +122,7 @@ func (conR *ConsensusReactor) SetPrivValidator(priv *PrivValidator) {
 func (conR *ConsensusReactor) Start() {
 	if atomic.CompareAndSwapUint32(&conR.started, 0, 1) {
 		log.Info("Starting ConsensusReactor")
-		go conR.proposeAndVoteRoutine()
+		go conR.stepTransitionRoutine()
 	}
 }
 
@@ -247,7 +247,7 @@ func (conR *ConsensusReactor) Receive(chId byte, peer *p2p.Peer, msgBytes []byte
 					msg := &HasVotesMessage{
 						Height:     rs.Height,
 						Round:      rs.Round,
-						Votes:      rs.Votes.BitArray(),
+						Prevotes:   rs.Prevotes.BitArray(),
 						Precommits: rs.Precommits.BitArray(),
 						Commits:    rs.Commits.BitArray(),
 					}
@@ -267,6 +267,113 @@ func (conR *ConsensusReactor) Receive(chId byte, peer *p2p.Peer, msgBytes []byte
 	}
 }
 
+//-------------------------------------
+
+type RoundAction struct {
+	Height uint32          // The block height for which consensus is reaching for.
+	Round  uint16          // The round number at given height.
+	Action RoundActionType // Action to perform.
+}
+
+// Source of all round state transitions (and votes).
+// It can be preemptively woken up via a message to
+// doActionCh.
+func (conR *ConsensusReactor) stepTransitionRoutine() {
+
+	scheduleNextAction := func() {
+		// Figure out which height/round/step we're at,
+		// then schedule an action for when it is due.
+		rs := conR.conS.GetRoundState()
+		_, _, roundDuration, _, elapsedRatio := calcRoundInfo(rs.StartTime)
+		switch rs.Step {
+		case RoundStepStart:
+			// It's a new RoundState.
+			if elapsedRatio < 0 {
+				// startTime is in the future.
+				time.Sleep(time.Duration(-1.0*elapsedRatio) * roundDuration)
+			}
+			conR.doActionCh <- RoundAction{rs.Height, rs.Round, RoundActionPropose}
+		case RoundStepPropose:
+			// Wake up when it's time to vote.
+			time.Sleep(time.Duration(roundDeadlinePrevote-elapsedRatio) * roundDuration)
+			conR.doActionCh <- RoundAction{rs.Height, rs.Round, RoundActionVote}
+		case RoundStepVote:
+			// Wake up when it's time to precommit.
+			time.Sleep(time.Duration(roundDeadlinePrecommit-elapsedRatio) * roundDuration)
+			conR.doActionCh <- RoundAction{rs.Height, rs.Round, RoundActionPrecommit}
+		case RoundStepPrecommit:
+			// Wake up when the round is over.
+			time.Sleep(time.Duration(1.0-elapsedRatio) * roundDuration)
+			conR.doActionCh <- RoundAction{rs.Height, rs.Round, RoundActionCommit}
+		case RoundStepCommit:
+			// Wake up when it's time to finalize commit.
+			time.Sleep(time.Duration(1.0-elapsedRatio)*roundDuration + finalizeDuration)
+			conR.doActionCh <- RoundAction{rs.Height, rs.Round, RoundActionFinalize}
+		default:
+			panic("Should not happen")
+		}
+	}
+
+	scheduleNextAction()
+
+	for {
+		roundAction := <-conR.doActionCh
+
+		height := roundAction.Height
+		round := roundAction.Round
+		action := roundAction.Action
+		rs := conR.conS.GetRoundState()
+		setStepAndBroadcast := func(step RoundStep) {
+			conR.conS.SetStep(step)
+			// Broadcast NewRoundStepMessage
+			msg := &NewRoundStepMessage{
+				Height: height,
+				Round:  round,
+				Step:   step,
+				SecondsSinceStartTime: uint32(rs.RoundElapsed().Seconds()),
+			}
+			conR.sw.Broadcast(StateCh, msg)
+		}
+
+		if height != rs.Height || round != rs.Round {
+			// Action is not relevant
+			// This may happen if an external routine
+			// pushes an action to conR.doActionCh.
+			return
+		}
+
+		// Run step
+		if action == RoundActionPropose && rs.Step == RoundStepStart {
+			conR.runStepPropose(rs)
+			setStepAndBroadcast(RoundStepPropose)
+		} else if action == RoundActionVote && rs.Step <= RoundStepPropose {
+			conR.runStepPrevote(rs)
+			setStepAndBroadcast(RoundStepVote)
+		} else if action == RoundActionPrecommit && rs.Step <= RoundStepVote {
+			conR.runStepPrecommit(rs)
+			setStepAndBroadcast(RoundStepPrecommit)
+		} else if action == RoundActionCommit && rs.Step <= RoundStepPrecommit {
+			committed := conR.runStepCommit(rs)
+			if committed {
+				setStepAndBroadcast(RoundStepCommit)
+			} else {
+				// runStepCommit() already set the round to the next round,
+				// so the step is already RoundStepStart (same height).
+			}
+		} else if action == RoundActionFinalize && rs.Step == RoundStepCommit {
+			conR.runStepFinalize(rs)
+			// Height has been incremented, step is now RoundStepStart.
+		} else {
+			// This shouldn't happen now, but if an external source pushes
+			// to conR.doActionCh, we might just want to continue here.
+			panic("Shouldn't happen")
+		}
+		scheduleNextAction()
+	}
+}
+
+//-------------------------------------
+
 func (conR *ConsensusReactor) gossipDataRoutine(peer *p2p.Peer, ps *PeerState) {
 
 OUTER_LOOP:
@@ -327,6 +434,8 @@ OUTER_LOOP:
 	}
 }
 
+//-------------------------------------
+
 func (conR *ConsensusReactor) gossipVotesRoutine(peer *p2p.Peer, ps *PeerState) {
 OUTER_LOOP:
 	for {
@@ -338,22 +447,22 @@ OUTER_LOOP:
 		rs := conR.conS.GetRoundState()
 		prs := ps.GetRoundState()
 
-		// If height doens't match, sleep.
+		// If height doesn't match, sleep.
 		if rs.Height != prs.Height {
 			time.Sleep(peerGossipSleepDuration)
 			continue OUTER_LOOP
 		}
 
-		// If there are bare votes to send...
+		// If there are prevotes to send...
 		if prs.Step <= RoundStepVote {
-			index, ok := rs.Votes.BitArray().Sub(prs.Votes).PickRandom()
+			index, ok := rs.Prevotes.BitArray().Sub(prs.Prevotes).PickRandom()
 			if ok {
 				valId, val := rs.Validators.GetByIndex(uint32(index))
 				if val != nil {
-					vote := rs.Votes.GetVote(valId)
+					vote := rs.Prevotes.Get(valId)
 					msg := p2p.TypedMessage{msgTypeVote, vote}
 					peer.Send(VoteCh, msg)
-					ps.SetHasVote(rs.Height, rs.Round, VoteTypeBare, uint32(index))
+					ps.SetHasVote(rs.Height, rs.Round, VoteTypePrevote, uint32(index))
 					continue OUTER_LOOP
 				} else {
 					log.Error("index is not a valid validator index")
@@ -367,7 +476,7 @@ OUTER_LOOP:
 			if ok {
 				valId, val := rs.Validators.GetByIndex(uint32(index))
 				if val != nil {
-					vote := rs.Precommits.GetVote(valId)
+					vote := rs.Precommits.Get(valId)
 					msg := p2p.TypedMessage{msgTypeVote, vote}
 					peer.Send(VoteCh, msg)
 					ps.SetHasVote(rs.Height, rs.Round, VoteTypePrecommit, uint32(index))
@@ -383,7 +492,7 @@ OUTER_LOOP:
 		if ok {
 			valId, val := rs.Validators.GetByIndex(uint32(index))
 			if val != nil {
-				vote := rs.Commits.GetVote(valId)
+				vote := rs.Commits.Get(valId)
 				msg := p2p.TypedMessage{msgTypeVote, vote}
 				peer.Send(VoteCh, msg)
 				ps.SetHasVote(rs.Height, rs.Round, VoteTypeCommit, uint32(index))
@@ -415,68 +524,62 @@ func (conR *ConsensusReactor) runStepPropose(rs *RoundState) {
 	conR.conS.MakeProposal()
 }
 
-func (conR *ConsensusReactor) runStepVote(rs *RoundState) {
-
+func (conR *ConsensusReactor) runStepPrevote(rs *RoundState) {
 	// If we have a locked block, we must vote for that.
 	// NOTE: a locked block is already valid.
 	if rs.LockedBlock != nil {
 		conR.signAndBroadcastVote(rs, &Vote{
 			Height:    rs.Height,
 			Round:     rs.Round,
-			Type:      VoteTypeBare,
+			Type:      VoteTypePrevote,
 			BlockHash: rs.LockedBlock.Hash(),
 		})
 	}
-
 	// Try staging proposed block.
 	// If Block is nil, an error is returned.
 	err := conR.conS.stageBlock(rs.ProposalBlock)
 	if err != nil {
-
-		// Vote nil
+		// Prevote nil
 		conR.signAndBroadcastVote(rs, &Vote{
 			Height:    rs.Height,
 			Round:     rs.Round,
-			Type:      VoteTypeBare,
+			Type:      VoteTypePrevote,
 			BlockHash: nil,
 		})
-
 	} else {
-
-		// Vote for block
+		// Prevote block
 		conR.signAndBroadcastVote(rs, &Vote{
 			Height:    rs.Height,
 			Round:     rs.Round,
-			Type:      VoteTypeBare,
+			Type:      VoteTypePrevote,
 			BlockHash: rs.ProposalBlock.Hash(),
 		})
 	}
 }
 
 func (conR *ConsensusReactor) runStepPrecommit(rs *RoundState) {
-
 	// If we see a 2/3 majority of votes for a block, lock.
 	hash := conR.conS.LockOrUnlock(rs.Height, rs.Round)
 	if len(hash) > 0 {
-
-		// Precommit
+		// Precommit block
 		conR.signAndBroadcastVote(rs, &Vote{
 			Height:    rs.Height,
 			Round:     rs.Round,
 			Type:      VoteTypePrecommit,
 			BlockHash: hash,
 		})
-
 	}
 }
 
 func (conR *ConsensusReactor) runStepCommit(rs *RoundState) bool {
-
-	// If we see a 2/3 majority of precommits for a block, commit.
-	block := conR.conS.Commit(rs.Height, rs.Round)
+	// If we see a 2/3 majority of votes for a block, lock.
+	block := conR.conS.TryCommit(rs.Height, rs.Round)
 	if block == nil {
+		// Couldn't commit, try next round.
+		conR.conS.SetupRound(rs.Round + 1)
 		return false
 	} else {
+		// Commit block.
 		conR.signAndBroadcastVote(rs, &Vote{
 			Height:    rs.Height,
 			Round:     rs.Round,
@@ -487,108 +590,9 @@ func (conR *ConsensusReactor) runStepCommit(rs *RoundState) bool {
 	}
 }
 
-//-------------------------------------
-
-type RoundAction struct {
-	Height       uint32        // The block height for which consensus is reaching for.
-	Round        uint16        // The round number at given height.
-	XnToStep     uint8         // Transition to this step. Action depends on this value.
-	RoundElapsed time.Duration // Duration since round start.
-}
-
-// Source of all round state transitions and votes.
-// It can be preemptively woken up via a message to
-// doActionCh.
-func (conR *ConsensusReactor) proposeAndVoteRoutine() {
-
-	// Figure out when to wake up next (in the absence of other events)
-	setAlarm := func() {
-		if len(conR.doActionCh) > 0 {
-			return // Already going to wake up later.
-		}
-
-		// Figure out which height/round/step we're at,
-		// then schedule an action for when it is due.
-		rs := conR.conS.GetRoundState()
-		_, _, roundDuration, roundElapsed, elapsedRatio := calcRoundInfo(rs.StartTime)
-		switch rs.Step {
-		case RoundStepStart:
-			// It's a new RoundState.
-			if elapsedRatio < 0 {
-				// startTime is in the future.
-				time.Sleep(time.Duration(-1.0*elapsedRatio) * roundDuration)
-			}
-			conR.doActionCh <- RoundAction{rs.Height, rs.Round, RoundStepPropose, roundElapsed}
-		case RoundStepPropose:
-			// Wake up when it's time to vote.
-			time.Sleep(time.Duration(roundDeadlineBare-elapsedRatio) * roundDuration)
-			conR.doActionCh <- RoundAction{rs.Height, rs.Round, RoundStepVote, roundElapsed}
-		case RoundStepVote:
-			// Wake up when it's time to precommit.
-			time.Sleep(time.Duration(roundDeadlinePrecommit-elapsedRatio) * roundDuration)
-			conR.doActionCh <- RoundAction{rs.Height, rs.Round, RoundStepPrecommit, roundElapsed}
-		case RoundStepPrecommit:
-			// Wake up when the round is over.
-			time.Sleep(time.Duration(1.0-elapsedRatio) * roundDuration)
-			conR.doActionCh <- RoundAction{rs.Height, rs.Round, RoundStepCommit, roundElapsed}
-		case RoundStepCommit:
-			// This shouldn't happen.
-			// Before setAlarm() got called,
-			// logic should have created a new RoundState for the next round.
-			panic("Should not happen")
-		}
-	}
-
-	for {
-		func() {
-			roundAction := <-conR.doActionCh
-			// Always set the alarm after any processing below.
-			defer setAlarm()
-
-			height := roundAction.Height
-			round := roundAction.Round
-			step := roundAction.XnToStep
-			roundElapsed := roundAction.RoundElapsed
-			rs := conR.conS.GetRoundState()
-
-			if height != rs.Height || round != rs.Round {
-				return // Action is not relevant
-			}
-
-			// Run step
-			if step == RoundStepPropose && rs.Step == RoundStepStart {
-				conR.runStepPropose(rs)
-			} else if step == RoundStepVote && rs.Step <= RoundStepPropose {
-				conR.runStepVote(rs)
-			} else if step == RoundStepPrecommit && rs.Step <= RoundStepVote {
-				conR.runStepPrecommit(rs)
-			} else if step == RoundStepCommit && rs.Step <= RoundStepPrecommit {
-				didCommit := conR.runStepCommit(rs)
-				if didCommit {
-					// We already set up ConsensusState for the next height
-					// (it happens in the call to conR.runStepCommit).
-				} else {
-					// Prepare a new RoundState for the next state.
-					conR.conS.SetupRound(rs.Round + 1)
-					return // setAlarm() takes care of the rest.
-				}
-			} else {
-				return // Action is not relevant.
-			}
-
-			// Transition to new step.
-			conR.conS.SetStep(step)
-
-			// Broadcast NewRoundStepMessage.
-			msg := &NewRoundStepMessage{
-				Height: height,
-				Round:  round,
-				Step:   step,
-				SecondsSinceStartTime: uint32(roundElapsed.Seconds()),
-			}
-			conR.sw.Broadcast(StateCh, msg)
-		}()
-	}
+func (conR *ConsensusReactor) runStepFinalize(rs *RoundState) {
+	// This actually updates the height and sets up round 0.
+	conR.conS.FinalizeCommit()
 }
 
 //-----------------------------------------------------------------------------
@@ -597,14 +601,14 @@ func (conR *ConsensusReactor) proposeAndVoteRoutine() {
 type PeerRoundState struct {
 	Height                uint32    // Height peer is at
 	Round                 uint16    // Round peer is at
-	Step                  uint8     // Step peer is at
+	Step                  RoundStep // Step peer is at
 	StartTime             time.Time // Estimated start of round 0 at this height
 	Proposal              bool      // True if peer has proposal for this round
 	ProposalBlockHash     []byte    // Block parts merkle root
 	ProposalBlockBitArray BitArray  // Block parts bitarray
 	ProposalPOLHash       []byte    // POL parts merkle root
 	ProposalPOLBitArray   BitArray  // POL parts bitarray
-	Votes                 BitArray  // All votes peer has for this round
+	Prevotes              BitArray  // All votes peer has for this round
 	Precommits            BitArray  // All precommits peer has for this round
 	Commits               BitArray  // All commits peer has for this height
 }
@@ -665,8 +669,8 @@ func (ps *PeerState) SetHasVote(height uint32, round uint16, type_ uint8, index
 	defer ps.mtx.Unlock()
 	if ps.Height == height && (ps.Round == round || type_ == VoteTypeCommit) {
 		switch type_ {
-		case VoteTypeBare:
-			ps.Votes.SetIndex(uint(index), true)
+		case VoteTypePrevote:
+			ps.Prevotes.SetIndex(uint(index), true)
 		case VoteTypePrecommit:
 			ps.Precommits.SetIndex(uint(index), true)
 		case VoteTypeCommit:
@@ -694,7 +698,7 @@ func (ps *PeerState) ApplyNewRoundStepMessage(msg *NewRoundStepMessage) error {
 	ps.ProposalBlockBitArray = nil
 	ps.ProposalPOLHash = nil
 	ps.ProposalPOLBitArray = nil
-	ps.Votes = nil
+	ps.Prevotes = nil
 	ps.Precommits = nil
 	if ps.Height != msg.Height {
 		ps.Commits = nil
@@ -708,10 +712,10 @@ func (ps *PeerState) ApplyHasVotesMessage(msg *HasVotesMessage) error {
 	if ps.Height == msg.Height {
 		ps.Commits = ps.Commits.Or(msg.Commits)
 		if ps.Round == msg.Round {
-			ps.Votes = ps.Votes.Or(msg.Votes)
+			ps.Prevotes = ps.Prevotes.Or(msg.Prevotes)
 			ps.Precommits = ps.Precommits.Or(msg.Precommits)
 		} else {
-			ps.Votes = msg.Votes
+			ps.Prevotes = msg.Prevotes
 			ps.Precommits = msg.Precommits
 		}
 	}
@@ -762,7 +766,7 @@ func decodeMessage(bz []byte) (msgType byte, msg interface{}) {
 type NewRoundStepMessage struct {
 	Height                uint32
 	Round                 uint16
-	Step                  uint8
+	Step                  RoundStep
 	SecondsSinceStartTime uint32
 }
 
@@ -770,7 +774,7 @@ func readNewRoundStepMessage(r io.Reader, n *int64, err *error) *NewRoundStepMes
 	return &NewRoundStepMessage{
 		Height: ReadUInt32(r, n, err),
 		Round:  ReadUInt16(r, n, err),
-		Step:   ReadUInt8(r, n, err),
+		Step:   RoundStep(ReadUInt8(r, n, err)),
 		SecondsSinceStartTime: ReadUInt32(r, n, err),
 	}
 }
@@ -779,7 +783,7 @@ func (m *NewRoundStepMessage) WriteTo(w io.Writer) (n int64, err error) {
 	WriteByte(w, msgTypeNewRoundStep, &n, &err)
 	WriteUInt32(w, m.Height, &n, &err)
 	WriteUInt16(w, m.Round, &n, &err)
-	WriteUInt8(w, m.Step, &n, &err)
+	WriteUInt8(w, uint8(m.Step), &n, &err)
 	WriteUInt32(w, m.SecondsSinceStartTime, &n, &err)
 	return
 }
@@ -793,7 +797,7 @@ func (m *NewRoundStepMessage) String() string {
 type HasVotesMessage struct {
 	Height     uint32
 	Round      uint16
-	Votes      BitArray
+	Prevotes   BitArray
 	Precommits BitArray
 	Commits    BitArray
 }
@@ -802,7 +806,7 @@ func readHasVotesMessage(r io.Reader, n *int64, err *error) *HasVotesMessage {
 	return &HasVotesMessage{
 		Height:     ReadUInt32(r, n, err),
 		Round:      ReadUInt16(r, n, err),
-		Votes:      ReadBitArray(r, n, err),
+		Prevotes:   ReadBitArray(r, n, err),
 		Precommits: ReadBitArray(r, n, err),
 		Commits:    ReadBitArray(r, n, err),
 	}
@@ -812,7 +816,7 @@ func (m *HasVotesMessage) WriteTo(w io.Writer) (n int64, err error) {
 	WriteByte(w, msgTypeHasVotes, &n, &err)
 	WriteUInt32(w, m.Height, &n, &err)
 	WriteUInt16(w, m.Round, &n, &err)
-	WriteBinary(w, m.Votes, &n, &err)
+	WriteBinary(w, m.Prevotes, &n, &err)
 	WriteBinary(w, m.Precommits, &n, &err)
 	WriteBinary(w, m.Commits, &n, &err)
 	return
diff --git a/consensus/pol.go b/consensus/pol.go
index efd82b65e..f6d43e2d0 100644
--- a/consensus/pol.go
+++ b/consensus/pol.go
@@ -11,7 +11,7 @@ import (
 )
 
 // Proof of lock.
-// +2/3 of validators' (bare) votes for a given blockhash (or nil)
+// +2/3 of validators' prevotes for a given blockhash (or nil)
 type POL struct {
 	Height       uint32
 	Round        uint16
@@ -47,7 +47,7 @@ func (pol *POL) Verify(vset *state.ValidatorSet) error {
 
 	talliedVotingPower := uint64(0)
 	voteDoc := BinaryBytes(&Vote{Height: pol.Height, Round: pol.Round,
-		Type: VoteTypeBare, BlockHash: pol.BlockHash})
+		Type: VoteTypePrevote, BlockHash: pol.BlockHash})
 	seenValidators := map[uint64]struct{}{}
 
 	for _, sig := range pol.Votes {
diff --git a/consensus/pol_test.go b/consensus/pol_test.go
index db622c1d7..5f8b84655 100644
--- a/consensus/pol_test.go
+++ b/consensus/pol_test.go
@@ -19,7 +19,7 @@ func TestVerifyVotes(t *testing.T) {
 		Height: 0, Round: 0, BlockHash: blockHash,
 	}
 	vote := &Vote{
-		Height: 0, Round: 0, Type: VoteTypeBare, BlockHash: blockHash,
+		Height: 0, Round: 0, Type: VoteTypePrevote, BlockHash: blockHash,
 	}
 	for i := 0; i < 6; i++ {
 		privAccounts[i].Sign(vote)
@@ -50,7 +50,7 @@ func TestVerifyInvalidVote(t *testing.T) {
 		Height: 0, Round: 0, BlockHash: blockHash,
 	}
 	vote := &Vote{
-		Height: 0, Round: 0, Type: VoteTypeBare, BlockHash: blockHash,
+		Height: 0, Round: 0, Type: VoteTypePrevote, BlockHash: blockHash,
 	}
 	for i := 0; i < 7; i++ {
 		privAccounts[i].Sign(vote)
@@ -168,7 +168,7 @@ func TestReadWrite(t *testing.T) {
 		Height: 0, Round: 0, BlockHash: blockHash,
 	}
 	vote := &Vote{
-		Height: 0, Round: 0, Type: VoteTypeBare, BlockHash: blockHash,
+		Height: 0, Round: 0, Type: VoteTypePrevote, BlockHash: blockHash,
 	}
 	for i := 0; i < 7; i++ {
 		privAccounts[i].Sign(vote)
diff --git a/consensus/priv_validator.go b/consensus/priv_validator.go
index aeb7e7787..929d38264 100644
--- a/consensus/priv_validator.go
+++ b/consensus/priv_validator.go
@@ -10,7 +10,11 @@ import (
 
 type PrivValidator struct {
 	state.PrivAccount
-	db *db_.LevelDB
+	db db_.DB
+}
+
+func NewPrivValidator(priv *state.PrivAccount, db db_.DB) *PrivValidator {
+	return &PrivValidator{*priv, db}
 }
 
 // Double signing results in a panic.
diff --git a/consensus/state.go b/consensus/state.go
index ccb9ab19e..938650526 100644
--- a/consensus/state.go
+++ b/consensus/state.go
@@ -9,16 +9,33 @@ import (
 	. "github.com/tendermint/tendermint/binary"
 	. "github.com/tendermint/tendermint/blocks"
 	. "github.com/tendermint/tendermint/common"
+	. "github.com/tendermint/tendermint/config"
 	"github.com/tendermint/tendermint/mempool"
 	"github.com/tendermint/tendermint/state"
 )
 
+type RoundStep uint8
+type RoundActionType uint8
+
 const (
-	RoundStepStart     = uint8(0x00) // Round started.
-	RoundStepPropose   = uint8(0x01) // Did propose, broadcasting proposal.
-	RoundStepVote      = uint8(0x02) // Did vote, broadcasting votes.
-	RoundStepPrecommit = uint8(0x03) // Did precommit, broadcasting precommits.
-	RoundStepCommit    = uint8(0x04) // We committed at this round -- do not progress to the next round.
+	RoundStepStart     = RoundStep(0x00) // Round started.
+	RoundStepPropose   = RoundStep(0x01) // Did propose, gossip proposal.
+	RoundStepVote      = RoundStep(0x02) // Did vote, gossip votes.
+	RoundStepPrecommit = RoundStep(0x03) // Did precommit, gossip precommits.
+	RoundStepCommit    = RoundStep(0x04) // Did commit, gossip commits.
+
+	// If a block could not be committed at a given round,
+	// we progress to the next round, skipping RoundStepCommit.
+	//
+	// If a block was committed, we goto RoundStepCommit,
+	// then wait "finalizeDuration" to gather more commit votes,
+	// then we progress to the next height at round 0.
+
+	RoundActionPropose   = RoundActionType(0x00) // Goto RoundStepPropose
+	RoundActionVote      = RoundActionType(0x01) // Goto RoundStepVote
+	RoundActionPrecommit = RoundActionType(0x02) // Goto RoundStepPrecommit
+	RoundActionCommit    = RoundActionType(0x03) // Goto RoundStepCommit or RoundStepStart next round
+	RoundActionFinalize  = RoundActionType(0x04) // Goto RoundStepStart next height
 )
 
 var (
@@ -31,7 +48,7 @@ var (
 type RoundState struct {
 	Height               uint32 // Height we are working on
 	Round                uint16
-	Step                 uint8
+	Step                 RoundStep
 	StartTime            time.Time
 	Validators           *state.ValidatorSet
 	Proposal             *Proposal
@@ -41,12 +58,17 @@ type RoundState struct {
 	ProposalPOLPartSet   *PartSet
 	LockedBlock          *Block
 	LockedPOL            *POL
-	Votes                *VoteSet
+	Prevotes             *VoteSet
 	Precommits           *VoteSet
 	Commits              *VoteSet
+	LastCommits          *VoteSet
 	PrivValidator        *PrivValidator
 }
 
+func (rs *RoundState) RoundElapsed() time.Duration {
+	return rs.StartTime.Sub(time.Now())
+}
+
 func (rs *RoundState) String() string {
 	return rs.StringWithIndent("")
 }
@@ -61,9 +83,10 @@ func (rs *RoundState) StringWithIndent(indent string) string {
 %s  ProposalPOL:   %v %v
 %s  LockedBlock:   %v
 %s  LockedPOL:     %v
-%s  Votes:      %v
-%s  Precommits: %v
-%s  Commits:    %v
+%s  Prevotes:      %v
+%s  Precommits:    %v
+%s  Commits:       %v
+%s  LastCommits:   %v
 %s}`,
 		indent, rs.Height, rs.Round, rs.Step,
 		indent, rs.StartTime,
@@ -73,9 +96,10 @@ func (rs *RoundState) StringWithIndent(indent string) string {
 		indent, rs.ProposalPOLPartSet.Description(), rs.ProposalPOL.Description(),
 		indent, rs.LockedBlock.Description(),
 		indent, rs.LockedPOL.Description(),
-		indent, rs.Votes.StringWithIndent(indent+"    "),
+		indent, rs.Prevotes.StringWithIndent(indent+"    "),
 		indent, rs.Precommits.StringWithIndent(indent+"    "),
 		indent, rs.Commits.StringWithIndent(indent+"    "),
+		indent, rs.LastCommits.StringWithIndent(indent+"    "),
 		indent)
 }
 
@@ -122,7 +146,7 @@ func (cs *ConsensusState) updateToState(state *state.State) {
 	cs.Height = height
 	cs.Round = 0
 	cs.Step = RoundStepStart
-	cs.StartTime = state.CommitTime.Add(newBlockWaitDuration)
+	cs.StartTime = state.CommitTime.Add(finalizeDuration)
 	cs.Validators = validators
 	cs.Proposal = nil
 	cs.ProposalBlock = nil
@@ -131,8 +155,9 @@ func (cs *ConsensusState) updateToState(state *state.State) {
 	cs.ProposalPOLPartSet = nil
 	cs.LockedBlock = nil
 	cs.LockedPOL = nil
-	cs.Votes = NewVoteSet(height, 0, VoteTypeBare, validators)
+	cs.Prevotes = NewVoteSet(height, 0, VoteTypePrevote, validators)
 	cs.Precommits = NewVoteSet(height, 0, VoteTypePrecommit, validators)
+	cs.LastCommits = cs.Commits
 	cs.Commits = NewVoteSet(height, 0, VoteTypeCommit, validators)
 
 	cs.state = state
@@ -171,13 +196,13 @@ func (cs *ConsensusState) setupRound(round uint16) {
 	cs.ProposalBlockPartSet = nil
 	cs.ProposalPOL = nil
 	cs.ProposalPOLPartSet = nil
-	cs.Votes = NewVoteSet(cs.Height, round, VoteTypeBare, validators)
-	cs.Votes.AddFromCommits(cs.Commits)
+	cs.Prevotes = NewVoteSet(cs.Height, round, VoteTypePrevote, validators)
+	cs.Prevotes.AddFromCommits(cs.Commits)
 	cs.Precommits = NewVoteSet(cs.Height, round, VoteTypePrecommit, validators)
 	cs.Precommits.AddFromCommits(cs.Commits)
 }
 
-func (cs *ConsensusState) SetStep(step byte) {
+func (cs *ConsensusState) SetStep(step RoundStep) {
 	cs.mtx.Lock()
 	defer cs.mtx.Unlock()
 	if cs.Step < step {
@@ -237,8 +262,26 @@ func (cs *ConsensusState) MakeProposal() {
 		block = cs.LockedBlock
 		pol = cs.LockedPOL
 	} else {
-		// TODO: make use of state returned from MakeProposalBlock()
-		block, _ = cs.mempool.MakeProposalBlock()
+		// We need to create a proposal.
+		// If we don't have enough commits from the last height,
+		// we can't do anything.
+		if !cs.LastCommits.HasTwoThirdsMajority() {
+			return
+		}
+		txs, state := cs.mempool.GetProposalTxs() // TODO: cache state
+		block = &Block{
+			Header: Header{
+				Network:       Config.Network,
+				Height:        cs.Height,
+				Time:          time.Now(),
+				LastBlockHash: cs.state.BlockHash,
+				StateHash:     state.Hash(),
+			},
+			Validation: cs.LastCommits.MakeValidation(),
+			Data: Data{
+				Txs: txs,
+			},
+		}
 		pol = cs.LockedPOL // If exists, is a PoUnlock.
 	}
 
@@ -317,15 +360,15 @@ func (cs *ConsensusState) AddProposalPOLPart(height uint32, round uint16, part *
 
 func (cs *ConsensusState) AddVote(vote *Vote) (added bool, err error) {
 	switch vote.Type {
-	case VoteTypeBare:
-		// Votes checks for height+round match.
-		return cs.Votes.Add(vote)
+	case VoteTypePrevote:
+		// Prevotes checks for height+round match.
+		return cs.Prevotes.Add(vote)
 	case VoteTypePrecommit:
 		// Precommits checks for height+round match.
 		return cs.Precommits.Add(vote)
 	case VoteTypeCommit:
 		// Commits checks for height match.
-		cs.Votes.Add(vote)
+		cs.Prevotes.Add(vote)
 		cs.Precommits.Add(vote)
 		return cs.Commits.Add(vote)
 	default:
@@ -344,10 +387,10 @@ func (cs *ConsensusState) LockOrUnlock(height uint32, round uint16) []byte {
 		return nil
 	}
 
-	if hash, _, ok := cs.Votes.TwoThirdsMajority(); ok {
+	if hash, _, ok := cs.Prevotes.TwoThirdsMajority(); ok {
 
 		// Remember this POL. (hash may be nil)
-		cs.LockedPOL = cs.Votes.MakePOL()
+		cs.LockedPOL = cs.Prevotes.MakePOL()
 
 		if len(hash) == 0 {
 			// +2/3 voted nil. Just unlock.
@@ -378,7 +421,12 @@ func (cs *ConsensusState) LockOrUnlock(height uint32, round uint16) []byte {
 	}
 }
 
-func (cs *ConsensusState) Commit(height uint32, round uint16) *Block {
+// Commits a block if we have enough precommits (and we have the block).
+// If successful, saves the block and state and resets mempool,
+// and returns the committed block.
+// Commit is not finalized until FinalizeCommit() is called.
+// This allows us to stay at this height and gather more commit votes.
+func (cs *ConsensusState) TryCommit(height uint32, round uint16) *Block {
 	cs.mtx.Lock()
 	defer cs.mtx.Unlock()
 
@@ -414,13 +462,11 @@ func (cs *ConsensusState) Commit(height uint32, round uint16) *Block {
 		// Save to blockStore
 		cs.blockStore.SaveBlock(block)
 
-		// What was staged becomes committed.
-		state := cs.stagedState
-		state.Save(commitTime)
-		cs.updateToState(state)
+		// Save the state
+		cs.stagedState.Save(commitTime)
 
 		// Update mempool.
-		cs.mempool.ResetForBlockAndState(block, state)
+		cs.mempool.ResetForBlockAndState(block, cs.stagedState)
 
 		return block
 	}
@@ -428,6 +474,13 @@ func (cs *ConsensusState) Commit(height uint32, round uint16) *Block {
 	return nil
 }
 
+// After TryCommit(), if successful, must call this in order to
+// update the RoundState.
+func (cs *ConsensusState) FinalizeCommit() {
+	// What was staged becomes committed.
+	cs.updateToState(cs.stagedState)
+}
+
 func (cs *ConsensusState) stageBlock(block *Block) error {
 
 	// Already staged?
diff --git a/consensus/state_test.go b/consensus/state_test.go
index 15c034368..5e97b2d18 100644
--- a/consensus/state_test.go
+++ b/consensus/state_test.go
@@ -45,16 +45,79 @@ func randGenesisState(numAccounts int, numValidators int) (*state.State, []*stat
 func makeConsensusState() (*ConsensusState, []*state.PrivAccount) {
 	state, privAccounts := randGenesisState(20, 10)
 	blockStore := NewBlockStore(db_.NewMemDB())
-	mempool := mempool.NewMempool(nil, state)
+	mempool := mempool.NewMempool(state)
 	cs := NewConsensusState(state, blockStore, mempool)
 	return cs, privAccounts
 }
 
-func TestUnit(t *testing.T) {
+//-----------------------------------------------------------------------------
+
+func TestSetupRound(t *testing.T) {
 	cs, privAccounts := makeConsensusState()
+
+	// Add a vote, precommit, and commit by val0.
+	voteTypes := []byte{VoteTypePrevote, VoteTypePrecommit, VoteTypeCommit}
+	for _, voteType := range voteTypes {
+		vote := &Vote{Height: 0, Round: 0, Type: voteType} // nil vote
+		privAccounts[0].Sign(vote)
+		cs.AddVote(vote)
+	}
+
+	// Ensure that vote appears in RoundState.
+	rs0 := cs.GetRoundState()
+	if vote := rs0.Prevotes.Get(0); vote == nil || vote.Type != VoteTypePrevote {
+		t.Errorf("Expected to find prevote %v, not there", vote)
+	}
+	if vote := rs0.Precommits.Get(0); vote == nil || vote.Type != VoteTypePrecommit {
+		t.Errorf("Expected to find precommit %v, not there", vote)
+	}
+	if vote := rs0.Commits.Get(0); vote == nil || vote.Type != VoteTypeCommit {
+		t.Errorf("Expected to find commit %v, not there", vote)
+	}
+
+	// Setup round 1 (next round)
+	cs.SetupRound(1)
+
+	// Now the commit should be copied over to prevotes and precommits.
+	rs1 := cs.GetRoundState()
+	if vote := rs1.Prevotes.Get(0); vote == nil || vote.Type != VoteTypeCommit {
+		t.Errorf("Expected to find commit %v, not there", vote)
+	}
+	if vote := rs1.Precommits.Get(0); vote == nil || vote.Type != VoteTypeCommit {
+		t.Errorf("Expected to find commit %v, not there", vote)
+	}
+	if vote := rs1.Commits.Get(0); vote == nil || vote.Type != VoteTypeCommit {
+		t.Errorf("Expected to find commit %v, not there", vote)
+	}
+
+	// Setup round 1 (should fail)
+	{
+		defer func() {
+			if e := recover(); e == nil {
+				t.Errorf("Expected to panic, round did not increment")
+			}
+		}()
+		cs.SetupRound(1)
+	}
+
+}
+
+func TestMakeProposalNoPrivValidator(t *testing.T) {
+	cs, _ := makeConsensusState()
+	cs.MakeProposal()
 	rs := cs.GetRoundState()
-	t.Log(rs)
-	if false {
-		t.Log(privAccounts)
+	if rs.Proposal != nil {
+		t.Error("Expected to make no proposal, since no privValidator")
 	}
 }
+
+func TestMakeProposalEmptyMempool(t *testing.T) {
+	cs, privAccounts := makeConsensusState()
+	priv := NewPrivValidator(privAccounts[0], db_.NewMemDB())
+	cs.SetPrivValidator(priv)
+
+	cs.MakeProposal()
+	rs := cs.GetRoundState()
+
+	t.Log(rs.Proposal)
+}
diff --git a/consensus/test.go b/consensus/test.go
index c614996c6..647422045 100644
--- a/consensus/test.go
+++ b/consensus/test.go
@@ -25,5 +25,5 @@ func makeVoteSet(height uint32, round uint16, numValidators int, votingPower uin
 		privAccounts[i] = privAccount
 	}
 	valSet := state.NewValidatorSet(vals)
-	return NewVoteSet(height, round, VoteTypeBare, valSet), valSet, privAccounts
+	return NewVoteSet(height, round, VoteTypePrevote, valSet), valSet, privAccounts
 }
diff --git a/consensus/vote_set.go b/consensus/vote_set.go
index c62c538ea..f330c21bd 100644
--- a/consensus/vote_set.go
+++ b/consensus/vote_set.go
@@ -14,7 +14,7 @@ import (
 
 // VoteSet helps collect signatures from validators at each height+round
 // for a predefined vote type.
-// Note that there three kinds of votes: (bare) votes, precommits, and commits.
+// Note that there three kinds of votes: prevotes, precommits, and commits.
 // A commit of prior rounds can be added added in lieu of votes/precommits.
 // TODO: test majority calculations etc.
 type VoteSet struct {
@@ -51,7 +51,7 @@ func NewVoteSet(height uint32, round uint16, type_ byte, vset *state.ValidatorSe
 
 // True if added, false if not.
 // Returns ErrVote[UnexpectedPhase|InvalidAccount|InvalidSignature|InvalidBlockHash|ConflictingSignature]
-// NOTE: vote should be mutated after adding.
+// NOTE: vote should not be mutated after adding.
 func (vs *VoteSet) Add(vote *Vote) (bool, error) {
 	vs.mtx.Lock()
 	defer vs.mtx.Unlock()
@@ -126,7 +126,7 @@ func (vs *VoteSet) BitArray() BitArray {
 	return vs.votesBitArray.Copy()
 }
 
-func (vs *VoteSet) GetVote(id uint64) *Vote {
+func (vs *VoteSet) Get(id uint64) *Vote {
 	vs.mtx.Lock()
 	defer vs.mtx.Unlock()
 	return vs.votes[id]
@@ -142,6 +142,15 @@ func (vs *VoteSet) AllVotes() []*Vote {
 	return votes
 }
 
+func (vs *VoteSet) HasTwoThirdsMajority() bool {
+	if vs == nil {
+		return false
+	}
+	vs.mtx.Lock()
+	defer vs.mtx.Unlock()
+	return !vs.twoThirdsCommitTime.IsZero()
+}
+
 // Returns either a blockhash (or nil) that received +2/3 majority.
 // If there exists no such majority, returns (nil, false).
 func (vs *VoteSet) TwoThirdsMajority() (hash []byte, commitTime time.Time, ok bool) {
@@ -154,6 +163,9 @@ func (vs *VoteSet) TwoThirdsMajority() (hash []byte, commitTime time.Time, ok bo
 }
 
 func (vs *VoteSet) MakePOL() *POL {
+	if vs.type_ != VoteTypePrevote {
+		panic("Cannot MakePOL() unless VoteSet.Type is VoteTypePrevote")
+	}
 	vs.mtx.Lock()
 	defer vs.mtx.Unlock()
 	if vs.twoThirdsCommitTime.IsZero() {
@@ -167,7 +179,7 @@ func (vs *VoteSet) MakePOL() *POL {
 	}
 	for _, vote := range vs.votes {
 		if bytes.Equal(vote.BlockHash, majHash) {
-			if vote.Type == VoteTypeBare {
+			if vote.Type == VoteTypePrevote {
 				pol.Votes = append(pol.Votes, vote.Signature)
 			} else if vote.Type == VoteTypeCommit {
 				pol.Commits = append(pol.Votes, vote.Signature)
@@ -180,6 +192,27 @@ func (vs *VoteSet) MakePOL() *POL {
 	return pol
 }
 
+func (vs *VoteSet) MakeValidation() Validation {
+	if vs.type_ != VoteTypeCommit {
+		panic("Cannot MakeValidation() unless VoteSet.Type is VoteTypePrevote")
+	}
+	vs.mtx.Lock()
+	defer vs.mtx.Unlock()
+	if len(vs.twoThirdsMajority) == 0 {
+		panic("Cannot MakeValidation() unless a blockhash has +2/3")
+	}
+	sigs := []Signature{}
+	for _, vote := range vs.votes {
+		if !bytes.Equal(vote.BlockHash, vs.twoThirdsMajority) {
+			continue
+		}
+		sigs = append(sigs, vote.Signature)
+	}
+	return Validation{
+		Signatures: sigs,
+	}
+}
+
 func (vs *VoteSet) String() string {
 	return vs.StringWithIndent("")
 }
@@ -189,8 +222,10 @@ func (vs *VoteSet) StringWithIndent(indent string) string {
 	defer vs.mtx.Unlock()
 
 	voteStrings := make([]string, len(vs.votes))
+	counter := 0
 	for _, vote := range vs.votes {
-		voteStrings[vote.SignerId] = vote.String()
+		voteStrings[counter] = vote.String()
+		counter++
 	}
 	return fmt.Sprintf(`VoteSet{
 %s  H:%v R:%v T:%v
diff --git a/consensus/vote_set_test.go b/consensus/vote_set_test.go
index d235ea4f7..50f77370e 100644
--- a/consensus/vote_set_test.go
+++ b/consensus/vote_set_test.go
@@ -14,8 +14,8 @@ func TestAddVote(t *testing.T) {
 
 	// t.Logf(">> %v", voteSet)
 
-	if voteSet.GetVote(0) != nil {
-		t.Errorf("Expected GetVote(0) to be nil")
+	if voteSet.Get(0) != nil {
+		t.Errorf("Expected Get(0) to be nil")
 	}
 	if voteSet.BitArray().GetIndex(0) {
 		t.Errorf("Expected BitArray.GetIndex(0) to be false")
@@ -25,12 +25,12 @@ func TestAddVote(t *testing.T) {
 		t.Errorf("There should be no 2/3 majority")
 	}
 
-	vote := &Vote{Height: 0, Round: 0, Type: VoteTypeBare, BlockHash: nil}
+	vote := &Vote{Height: 0, Round: 0, Type: VoteTypePrevote, BlockHash: nil}
 	privAccounts[0].Sign(vote)
 	voteSet.Add(vote)
 
-	if voteSet.GetVote(0) == nil {
-		t.Errorf("Expected GetVote(0) to be present")
+	if voteSet.Get(0) == nil {
+		t.Errorf("Expected Get(0) to be present")
 	}
 	if !voteSet.BitArray().GetIndex(0) {
 		t.Errorf("Expected BitArray.GetIndex(0) to be true")
@@ -45,7 +45,7 @@ func Test2_3Majority(t *testing.T) {
 	voteSet, _, privAccounts := makeVoteSet(0, 0, 10, 1)
 
 	// 6 out of 10 voted for nil.
-	vote := &Vote{Height: 0, Round: 0, Type: VoteTypeBare, BlockHash: nil}
+	vote := &Vote{Height: 0, Round: 0, Type: VoteTypePrevote, BlockHash: nil}
 	for i := 0; i < 6; i++ {
 		privAccounts[i].Sign(vote)
 		voteSet.Add(vote)
@@ -79,7 +79,7 @@ func TestBadVotes(t *testing.T) {
 	voteSet, _, privAccounts := makeVoteSet(1, 0, 10, 1)
 
 	// val0 votes for nil.
-	vote := &Vote{Height: 1, Round: 0, Type: VoteTypeBare, BlockHash: nil}
+	vote := &Vote{Height: 1, Round: 0, Type: VoteTypePrevote, BlockHash: nil}
 	privAccounts[0].Sign(vote)
 	added, err := voteSet.Add(vote)
 	if !added || err != nil {
@@ -87,7 +87,7 @@ func TestBadVotes(t *testing.T) {
 	}
 
 	// val0 votes again for some block.
-	vote = &Vote{Height: 1, Round: 0, Type: VoteTypeBare, BlockHash: CRandBytes(32)}
+	vote = &Vote{Height: 1, Round: 0, Type: VoteTypePrevote, BlockHash: CRandBytes(32)}
 	privAccounts[0].Sign(vote)
 	added, err = voteSet.Add(vote)
 	if added || err == nil {
@@ -95,7 +95,7 @@ func TestBadVotes(t *testing.T) {
 	}
 
 	// val1 votes on another height
-	vote = &Vote{Height: 0, Round: 0, Type: VoteTypeBare, BlockHash: nil}
+	vote = &Vote{Height: 0, Round: 0, Type: VoteTypePrevote, BlockHash: nil}
 	privAccounts[1].Sign(vote)
 	added, err = voteSet.Add(vote)
 	if added {
@@ -103,7 +103,7 @@ func TestBadVotes(t *testing.T) {
 	}
 
 	// val2 votes on another round
-	vote = &Vote{Height: 1, Round: 1, Type: VoteTypeBare, BlockHash: nil}
+	vote = &Vote{Height: 1, Round: 1, Type: VoteTypePrevote, BlockHash: nil}
 	privAccounts[2].Sign(vote)
 	added, err = voteSet.Add(vote)
 	if added {
@@ -119,11 +119,11 @@ func TestBadVotes(t *testing.T) {
 	}
 }
 
-func TestAddCommitsToBareVotes(t *testing.T) {
+func TestAddCommitsToPrevoteVotes(t *testing.T) {
 	voteSet, _, privAccounts := makeVoteSet(1, 5, 10, 1)
 
 	// val0, val1, val2, val3, val4, val5 vote for nil.
-	vote := &Vote{Height: 1, Round: 5, Type: VoteTypeBare, BlockHash: nil}
+	vote := &Vote{Height: 1, Round: 5, Type: VoteTypePrevote, BlockHash: nil}
 	for i := 0; i < 6; i++ {
 		privAccounts[i].Sign(vote)
 		voteSet.Add(vote)
diff --git a/mempool/mempool.go b/mempool/mempool.go
index bcdfb442e..37a3685b8 100644
--- a/mempool/mempool.go
+++ b/mempool/mempool.go
@@ -17,16 +17,14 @@ import (
 )
 
 type Mempool struct {
-	mtx       sync.Mutex
-	lastBlock *Block
-	state     *state.State
-	txs       []Tx
+	mtx   sync.Mutex
+	state *state.State
+	txs   []Tx
 }
 
-func NewMempool(lastBlock *Block, state *state.State) *Mempool {
+func NewMempool(state *state.State) *Mempool {
 	return &Mempool{
-		lastBlock: lastBlock,
-		state:     state,
+		state: state,
 	}
 }
 
@@ -43,14 +41,10 @@ func (mem *Mempool) AddTx(tx Tx) (err error) {
 	}
 }
 
-// Returns a new block from the current state and associated transactions.
-// The block's Validation is empty, and some parts of the header too.
-func (mem *Mempool) MakeProposalBlock() (*Block, *state.State) {
+func (mem *Mempool) GetProposalTxs() ([]Tx, *state.State) {
 	mem.mtx.Lock()
 	defer mem.mtx.Unlock()
-	nextBlock := mem.lastBlock.MakeNextBlock()
-	nextBlock.Data.Txs = mem.txs
-	return nextBlock, mem.state
+	return mem.txs, mem.state
 }
 
 // "block" is the new block being committed.
@@ -60,7 +54,6 @@ func (mem *Mempool) MakeProposalBlock() (*Block, *state.State) {
 func (mem *Mempool) ResetForBlockAndState(block *Block, state *state.State) {
 	mem.mtx.Lock()
 	defer mem.mtx.Unlock()
-	mem.lastBlock = block
 	mem.state = state.Copy()
 
 	// First, create a lookup map of txns in new block.
diff --git a/state/state.go b/state/state.go
index 978f461dc..b706869e0 100644
--- a/state/state.go
+++ b/state/state.go
@@ -46,9 +46,9 @@ type State struct {
 	Height              uint32 // Last known block height
 	BlockHash           []byte // Last known block hash
 	CommitTime          time.Time
-	accountDetails      merkle.Tree // Shouldn't be accessed directly.
 	BondedValidators    *ValidatorSet
 	UnbondingValidators *ValidatorSet
+	accountDetails      merkle.Tree // Shouldn't be accessed directly.
 }
 
 func GenesisState(db db_.DB, genesisTime time.Time, accDets []*AccountDetail) *State {
@@ -78,9 +78,9 @@ func GenesisState(db db_.DB, genesisTime time.Time, accDets []*AccountDetail) *S
 		Height:              0,
 		BlockHash:           nil,
 		CommitTime:          genesisTime,
-		accountDetails:      accountDetails,
 		BondedValidators:    NewValidatorSet(validators),
 		UnbondingValidators: NewValidatorSet(nil),
+		accountDetails:      accountDetails,
 	}
 }
 
@@ -96,11 +96,11 @@ func LoadState(db db_.DB) *State {
 		s.Height = ReadUInt32(reader, &n, &err)
 		s.CommitTime = ReadTime(reader, &n, &err)
 		s.BlockHash = ReadByteSlice(reader, &n, &err)
+		s.BondedValidators = ReadValidatorSet(reader, &n, &err)
+		s.UnbondingValidators = ReadValidatorSet(reader, &n, &err)
 		accountDetailsHash := ReadByteSlice(reader, &n, &err)
 		s.accountDetails = merkle.NewIAVLTree(BasicCodec, AccountDetailCodec, defaultAccountDetailsCacheCapacity, db)
 		s.accountDetails.Load(accountDetailsHash)
-		s.BondedValidators = ReadValidatorSet(reader, &n, &err)
-		s.UnbondingValidators = ReadValidatorSet(reader, &n, &err)
 		if err != nil {
 			panic(err)
 		}
@@ -121,9 +121,9 @@ func (s *State) Save(commitTime time.Time) {
 	WriteUInt32(&buf, s.Height, &n, &err)
 	WriteTime(&buf, commitTime, &n, &err)
 	WriteByteSlice(&buf, s.BlockHash, &n, &err)
-	WriteByteSlice(&buf, s.accountDetails.Hash(), &n, &err)
 	WriteBinary(&buf, s.BondedValidators, &n, &err)
 	WriteBinary(&buf, s.UnbondingValidators, &n, &err)
+	WriteByteSlice(&buf, s.accountDetails.Hash(), &n, &err)
 	if err != nil {
 		panic(err)
 	}
@@ -136,9 +136,9 @@ func (s *State) Copy() *State {
 		Height:              s.Height,
 		CommitTime:          s.CommitTime,
 		BlockHash:           s.BlockHash,
-		accountDetails:      s.accountDetails.Copy(),
 		BondedValidators:    s.BondedValidators.Copy(),
 		UnbondingValidators: s.UnbondingValidators.Copy(),
+		accountDetails:      s.accountDetails.Copy(),
 	}
 }
 
@@ -421,9 +421,9 @@ func (s *State) SetAccountDetail(accDet *AccountDetail) (updated bool) {
 // excluding Height, BlockHash, and CommitTime.
 func (s *State) Hash() []byte {
 	hashables := []merkle.Hashable{
-		s.accountDetails,
 		s.BondedValidators,
 		s.UnbondingValidators,
+		s.accountDetails,
 	}
 	return merkle.HashFromHashables(hashables)
 }