Add in Proposer Index to Custom HTR (#5269)

* fix test

* Update beacon-chain/state/stateutil/blocks_test.go

Co-authored-by: terence tsao <terence@prysmaticlabs.com>
Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>

beacon-chain/state/stateutil/blocks.go

@@ -42,21 +42,25 @@ func BlockRoot(blk *ethpb.BeaconBlock) ([32]byte, error) {
 	if !featureconfig.Get().EnableBlockHTR {
 		return ssz.HashTreeRoot(blk)
 	}
-	fieldRoots := make([][32]byte, 4)
+	fieldRoots := make([][32]byte, 5)
 	if blk != nil {
 		headerSlotBuf := make([]byte, 8)
 		binary.LittleEndian.PutUint64(headerSlotBuf, blk.Slot)
 		headerSlotRoot := bytesutil.ToBytes32(headerSlotBuf)
 		fieldRoots[0] = headerSlotRoot
+		proposerIdxBuf := make([]byte, 8)
+		binary.LittleEndian.PutUint64(proposerIdxBuf, blk.ProposerIndex)
+		proposerIndexRoot := bytesutil.ToBytes32(proposerIdxBuf)
+		fieldRoots[1] = proposerIndexRoot
 		parentRoot := bytesutil.ToBytes32(blk.ParentRoot)
-		fieldRoots[1] = parentRoot
+		fieldRoots[2] = parentRoot
 		stateRoot := bytesutil.ToBytes32(blk.StateRoot)
-		fieldRoots[2] = stateRoot
+		fieldRoots[3] = stateRoot
 		bodyRoot, err := BlockBodyRoot(blk.Body)
 		if err != nil {
 			return [32]byte{}, err
 		}
-		fieldRoots[3] = bodyRoot
+		fieldRoots[4] = bodyRoot
 	}
 	return bitwiseMerkleizeArrays(hashutil.CustomSHA256Hasher(), fieldRoots, uint64(len(fieldRoots)), uint64(len(fieldRoots)))
 }

beacon-chain/state/stateutil/blocks_test.go

@@ -3,12 +3,16 @@ package stateutil_test
 import (
 	"testing"
 
+	"github.com/prysmaticlabs/prysm/shared/featureconfig"
 	"github.com/prysmaticlabs/go-ssz"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateutil"
 	"github.com/prysmaticlabs/prysm/shared/testutil"
 )
 
 func TestBlockRoot(t *testing.T) {
+	f := featureconfig.Get()
+	f.EnableBlockHTR = true
+	featureconfig.Init(f)
 	genState, keys := testutil.DeterministicGenesisState(t, 100)
 	blk, err := testutil.GenerateFullBlock(genState, keys, testutil.DefaultBlockGenConfig(), 10)
 	if err != nil {