Apply suggestions from code review

Co-authored-by: M. J. Fromberger <fromberger@interchain.io>

internal/blocksync/reactor.go

@@ -188,7 +188,7 @@ func (r *Reactor) respondToPeer(ctx context.Context, msg *bcproto.BlockRequest,
 	if block != nil {
 		extCommit := r.store.LoadBlockExtendedCommit(msg.Height)
 		if extCommit == nil {
-			return fmt.Errorf("blockstore has block but not extended commit (block: %v)", block)
+			return fmt.Errorf("found block in store without extended commit: %v", block)
 		}
 		blockProto, err := block.ToProto()
 		if err != nil {
@@ -465,7 +465,7 @@ func (r *Reactor) poolRoutine(ctx context.Context, stateSynced bool, blockSyncCh
 			switch {
 			//case state.LastBlockHeight > 0 && r.store.LoadBlockExtCommit(state.LastBlockHeight) == nil:
 			case state.LastBlockHeight > 0 && blocksSynced == 0:
-				//If we have state-synced, we need to blocksync at least one block
+				// Having state-synced, we need to blocksync at least one block
 				r.logger.Info(
 					"no seen commit yet",
 					"height", height,

internal/evidence/pool_test.go

@@ -589,7 +589,6 @@ func initializeBlockStore(db dbm.DB, state sm.State, valAddr []byte) (*store.Blo
 func makeExtCommit(height int64, valAddr []byte) *types.ExtendedCommit {
 	return &types.ExtendedCommit{
 		Height:  height,
-		BlockID: types.BlockID{},
 		ExtendedSignatures: []types.ExtendedCommitSig{{
 			CommitSig: types.CommitSig{
 				BlockIDFlag:      types.BlockIDFlagCommit,

internal/state/execution.go

@@ -414,11 +414,13 @@ func buildLastCommitInfo(block *types.Block, store Store, initialHeight int64) a
 	}
 }
 
-// buildLastExtendedCommitInfo expects an ExtendedCommitInfo, which includes
-// the original precommit votes along with their vote extensions from the last
-// commit. It populates the corresponding ABCI protobuf structures using the
-// validator set obtained from the store at the height of the last extended
-// commit.
+// buildLastExtendedCommitInfo populates an ABCI extended commit from the
+// corresponding Tendermint extended commit ec, using the stored validator set from
+// ec.  It requires ec to include the original precommit votes along
+// with the vote extensions from the last commit.
+//
+// For heights below the initial height, for which we do not have the
+// required data, it returns an empty record.
 func buildLastExtendedCommitInfo(ec *types.ExtendedCommit, store Store, initialHeight int64) abci.ExtendedCommitInfo {
 	// We assume the current height is ec.Height + 1.
 	if ec.Height < initialHeight {

internal/state/execution_test.go

@@ -328,11 +328,10 @@ func TestProcessProposal(t *testing.T) {
 		lastCommitSig = append(lastCommitSig, vote.CommitSig())
 	}
 
-	lastCommit := &types.Commit{
+	block1 := sf.MakeBlock(state, height, &types.Commit{
 		Height:     height - 1,
 		Signatures: lastCommitSig,
-	}
-	block1 := sf.MakeBlock(state, height, lastCommit)
+	})
 	block1.Txs = txs
 
 	expectedRpp := &abci.RequestProcessProposal{

internal/store/store.go

@@ -273,16 +273,16 @@ func (bs *BlockStore) LoadBlockCommit(height int64) *types.Commit {
 	}
 	commit, err := types.CommitFromProto(pbc)
 	if err != nil {
-		panic(fmt.Errorf("error from proto block commit: %w", err))
+		panic(fmt.Errorf("converting commit to proto: %w", err))
 	}
 	return commit
 }
 
 func (bs *BlockStore) LoadBlockExtendedCommit(height int64) *types.ExtendedCommit {
-	var pbec = new(tmproto.ExtendedCommit)
+	pbec := new(tmproto.ExtendedCommit)
 	bz, err := bs.db.Get(extCommitKey(height))
 	if err != nil {
-		panic(err)
+		panic(fmt.Errorf("fetching extended commit: %w", err))
 	}
 	if len(bz) == 0 {
 		return nil

internal/store/store_test.go

@@ -310,7 +310,7 @@ func TestLoadBlockPart(t *testing.T) {
 	require.NoError(t, err)
 
 	bs, db := newInMemoryBlockStore()
-	height, index := int64(10), 1
+	const height, index = 10, 1
 	loadPart := func() (interface{}, error) {
 		part := bs.LoadBlockPart(height, index)
 		return part, nil

types/block.go

@@ -1074,9 +1074,7 @@ func (ec *ExtendedCommit) Type() byte { return byte(tmproto.PrecommitType) }
 
 // GetHeight returns height of the extended commit.
 // Implements VoteSetReader.
-func (ec *ExtendedCommit) GetHeight() int64 {
-	return ec.Height
-}
+func (ec *ExtendedCommit) GetHeight() int64 { return ec.Height }
 
 // GetRound returns height of the extended commit.
 // Implements VoteSetReader.
@@ -1175,9 +1173,7 @@ func ExtendedCommitFromProto(ecp *tmproto.ExtendedCommit) (*ExtendedCommit, erro
 		return nil, errors.New("nil ExtendedCommit")
 	}
 
-	var (
-		extCommit = new(ExtendedCommit)
-	)
+	extCommit := new(ExtendedCommit)
 
 	bi, err := BlockIDFromProto(&ecp.BlockID)
 	if err != nil {
@@ -1191,7 +1187,6 @@ func ExtendedCommitFromProto(ecp *tmproto.ExtendedCommit) (*ExtendedCommit, erro
 		}
 	}
 	extCommit.ExtendedSignatures = sigs
-
 	extCommit.Height = ecp.Height
 	extCommit.Round = ecp.Round
 	extCommit.BlockID = *bi