From d7f6c0775aa5563ce9f8aa86fd14bf618a21cf84 Mon Sep 17 00:00:00 2001
From: Ethan Buchman <ethan@coinculture.info>
Date: Wed, 16 Nov 2016 20:58:53 -0500
Subject: [PATCH] remove LastCommitHeight

---
 consensus/state.go |  3 ++-
 state/execution.go | 31 +++++++++----------------------
 types/validator.go | 20 ++++++++------------
 3 files changed, 19 insertions(+), 35 deletions(-)

diff --git a/consensus/state.go b/consensus/state.go
index 0442fb829..78a9b4f52 100644
--- a/consensus/state.go
+++ b/consensus/state.go
@@ -1522,7 +1522,8 @@ func (cs *ConsensusState) signVote(type_ byte, hash []byte, header types.PartSet
 
 // sign the vote and publish on internalMsgQueue
 func (cs *ConsensusState) signAddVote(type_ byte, hash []byte, header types.PartSetHeader) *types.Vote {
-	if cs.privValidator == nil || !cs.Validators.HasAddress(cs.privValidator.GetAddress()) {
+	// if we don't have a key or we're not in the validator set, do nothing
+	if cs.privValidator == nil || cs.privValidatorIndex < 0 {
 		return nil
 	}
 	vote, err := cs.signVote(type_, hash, header)
diff --git a/state/execution.go b/state/execution.go
index c52be41dc..2b8461bed 100644
--- a/state/execution.go
+++ b/state/execution.go
@@ -29,7 +29,9 @@ func (s *State) ExecBlock(eventCache types.Fireable, proxyAppConn proxy.AppConnC
 	// Update the validator set
 	valSet := s.Validators.Copy()
 	// Update valSet with signatures from block.
-	updateValidatorsWithBlock(s.LastValidators, valSet, block)
+	signed := commitBitArrayFromBlock(block)
+	_ = signed // TODO
+
 	// TODO: Update the validator set (e.g. block.Data.ValidatorUpdates?)
 	nextValSet := valSet.Copy()
 
@@ -126,32 +128,17 @@ func (s *State) execBlockOnProxyApp(eventCache types.Fireable, proxyAppConn prox
 	return nil
 }
 
-// Updates the LastCommitHeight of the validators in valSet, in place.
-// Assumes that lastValSet matches the valset of block.LastCommit
-// CONTRACT: lastValSet is not mutated.
-func updateValidatorsWithBlock(lastValSet *types.ValidatorSet, valSet *types.ValidatorSet, block *types.Block) {
-
+// return a bit array of validators that signed the last commit
+// NOTE: assumes commits have already been authenticated
+func commitBitArrayFromBlock(block *types.Block) *BitArray {
+	signed := NewBitArray(len(block.LastCommit.Precommits))
 	for i, precommit := range block.LastCommit.Precommits {
 		if precommit == nil {
 			continue
 		}
-		_, val := lastValSet.GetByIndex(i)
-		if val == nil {
-			PanicCrisis(Fmt("Failed to fetch validator at index %v", i))
-		}
-		if _, val_ := valSet.GetByAddress(val.Address); val_ != nil {
-			val_.LastCommitHeight = block.Height - 1
-			updated := valSet.Update(val_)
-			if !updated {
-				PanicCrisis("Failed to update validator LastCommitHeight")
-			}
-		} else {
-			// XXX This is not an error if validator was removed.
-			// But, we don't mutate validators yet so go ahead and panic.
-			PanicCrisis("Could not find validator")
-		}
+		signed.SetIndex(i, true) // val_.LastCommitHeight = block.Height - 1
 	}
-
+	return signed
 }
 
 //-----------------------------------------------------
diff --git a/types/validator.go b/types/validator.go
index 2e45ebba9..7adb64dbb 100644
--- a/types/validator.go
+++ b/types/validator.go
@@ -12,14 +12,12 @@ import (
 
 // Volatile state for each Validator
 // TODO: make non-volatile identity
-// 	- Remove LastCommitHeight, send bitarray of vals that signed in BeginBlock
 // 	- Remove Accum - it can be computed, and now valset becomes identifying
 type Validator struct {
-	Address          []byte        `json:"address"`
-	PubKey           crypto.PubKey `json:"pub_key"`
-	LastCommitHeight int           `json:"last_commit_height"`
-	VotingPower      int64         `json:"voting_power"`
-	Accum            int64         `json:"accum"`
+	Address     []byte        `json:"address"`
+	PubKey      crypto.PubKey `json:"pub_key"`
+	VotingPower int64         `json:"voting_power"`
+	Accum       int64         `json:"accum"`
 }
 
 // Creates a new copy of the validator so we can mutate accum.
@@ -57,7 +55,6 @@ func (v *Validator) String() string {
 	return fmt.Sprintf("Validator{%X %v %v VP:%v A:%v}",
 		v.Address,
 		v.PubKey,
-		v.LastCommitHeight,
 		v.VotingPower,
 		v.Accum)
 }
@@ -97,11 +94,10 @@ func RandValidator(randPower bool, minPower int64) (*Validator, *PrivValidator)
 		votePower += int64(RandUint32())
 	}
 	val := &Validator{
-		Address:          privVal.Address,
-		PubKey:           privVal.PubKey,
-		LastCommitHeight: 0,
-		VotingPower:      votePower,
-		Accum:            0,
+		Address:     privVal.Address,
+		PubKey:      privVal.PubKey,
+		VotingPower: votePower,
+		Accum:       0,
 	}
 	return val, privVal
 }