feat: simapp/v2 (#20412)

Co-authored-by: marbar3778 <marbar3778@yahoo.com>
Co-authored-by: Marko <marko@baricevic.me>
Co-authored-by: Likhita Polavarapu <78951027+likhita-809@users.noreply.github.com>
Co-authored-by: unknown unknown <unknown@unknown>

core/header/service.go

@@ -33,6 +33,10 @@ func (i *Info) Bytes() ([]byte, error) {
 	binary.LittleEndian.PutUint64(heightBytes, uint64(i.Height))
 	buf = append(buf, heightBytes...)
 
+	// TODO; permit empty hash OK for genesis block?
+	if len(i.Hash) == 0 {
+		i.Hash = make([]byte, hashSize)
+	}
 	// Encode Hash
 	if len(i.Hash) != hashSize {
 		return nil, errors.New("invalid hash size")
@@ -44,6 +48,9 @@ func (i *Info) Bytes() ([]byte, error) {
 	binary.LittleEndian.PutUint64(timeBytes, uint64(i.Time.Unix()))
 	buf = append(buf, timeBytes...)
 
+	if len(i.AppHash) == 0 {
+		i.AppHash = make([]byte, hashSize)
+	}
 	// Encode AppHash
 	if len(i.Hash) != hashSize {
 		return nil, errors.New("invalid hash size")