Accounting for unparsed header bytes

ergo-core/src/main/scala/org/ergoplatform/mining/AutolykosPowScheme.scala

@@ -262,7 +262,7 @@ class AutolykosPowScheme(val k: Int, val n: Int) extends ScorexLogging {
     val (parentId, height) = AutolykosPowScheme.derivedHeaderFields(parentOpt)
 
     val h = HeaderWithoutPow(version, parentId, adProofsRoot, stateRoot, transactionsRoot, timestamp,
-      nBits, height, extensionHash, votes)
+      nBits, height, extensionHash, votes, Array.emptyByteArray)
     val msg = msgByHeader(h)
     val b = getB(nBits)
     val x = randomSecret()

ergo-core/src/main/scala/org/ergoplatform/mining/CandidateUtils.scala

@@ -29,7 +29,8 @@ object CandidateUtils {
       candidate.nBits,
       height,
       extensionRoot,
-      candidate.votes
+      candidate.votes,
+      Array.emptyByteArray
     )
   }
 }

ergo-core/src/main/scala/org/ergoplatform/mining/DefaultFakePowScheme.scala

@@ -33,7 +33,7 @@ class DefaultFakePowScheme(k: Int, n: Int) extends AutolykosPowScheme(k, n) {
     val d: BigInt = q / (height + 10)
     val s = AutolykosSolution(pk, w, n, d)
     Some(Header(version, parentId, adProofsRoot, stateRoot, transactionsRoot, timestamp,
-      nBits, height, extensionHash, s, votes))
+      nBits, height, extensionHash, s, votes, Array.emptyByteArray))
   }
 
   override def realDifficulty(header: Header): PrivateKey = header.requiredDifficulty

ergo-core/src/main/scala/org/ergoplatform/modifiers/history/header/Header.scala

@@ -40,6 +40,7 @@ import scala.concurrent.duration.FiniteDuration
   * @param extensionRoot - Merkle tree digest of the extension section of the block
   * @param powSolution - solution for the proof-of-work puzzle
   * @param votes - votes for changing system parameters
+  * @param unparsedBytes - bytes of fields added in future versions of the protocol and not parseable
   * @param sizeOpt - optionally, size of the header (to avoid serialization on calling .length)
   */
 case class Header(override val version: Header.Version,
@@ -53,8 +54,9 @@ case class Header(override val version: Header.Version,
                   override val extensionRoot: Digest32,
                   powSolution: AutolykosSolution,
                   override val votes: Array[Byte], //3 bytes
+                  override val unparsedBytes: Array[Byte],
                   override val sizeOpt: Option[Int] = None) extends HeaderWithoutPow(version, parentId, ADProofsRoot, stateRoot, transactionsRoot, timestamp,
-  nBits, height, extensionRoot, votes) with PreHeader with BlockSection {
+  nBits, height, extensionRoot, votes, unparsedBytes) with PreHeader with BlockSection {
 
   override def serializedId: Array[Header.Version] = Algos.hash(bytes)
 
@@ -138,6 +140,11 @@ object Header extends ApiCodecs {
     */
   val Interpreter50Version: Byte = 3
 
+  /**
+    * Block version after the 6.0 soft-fork
+    * 6.0 interpreter (EIP-50)
+    */
+  val Interpreter60Version: Byte = 4
 
   def toSigma(header: Header): sigma.Header =
     CHeader(
@@ -180,7 +187,8 @@ object Header extends ApiCodecs {
       "size" -> h.size.asJson,
       "extensionId" -> Algos.encode(h.extensionId).asJson,
       "transactionsId" -> Algos.encode(h.transactionsId).asJson,
-      "adProofsId" -> Algos.encode(h.ADProofsId).asJson
+      "adProofsId" -> Algos.encode(h.ADProofsId).asJson,
+      "unparsedBytes" -> Algos.encode(h.unparsedBytes).asJson
     ).asJson
   }
 
@@ -197,8 +205,10 @@ object Header extends ApiCodecs {
       version <- c.downField("version").as[Byte]
       votes <- c.downField("votes").as[String]
       solutions <- c.downField("powSolutions").as[AutolykosSolution]
+      unparsedBytes <- c.downField("unparsedBytes").as[Option[Array[Byte]]]
     } yield Header(version, parentId, adProofsRoot, stateRoot,
-      transactionsRoot, timestamp, nBits, height, extensionHash, solutions, Algos.decode(votes).get)
+      transactionsRoot, timestamp, nBits, height, extensionHash, solutions, Algos.decode(votes).get,
+      unparsedBytes.getOrElse(Array.emptyByteArray))
   }
 
 }

ergo-core/src/main/scala/org/ergoplatform/modifiers/history/header/HeaderSerializer.scala

@@ -32,7 +32,8 @@ object HeaderSerializer extends ErgoSerializer[Header] {
     // For block version >= 2, this new byte encodes length of possible new fields.
     // Set to 0 for now, so no new fields.
     if (h.version > Header.InitialVersion) {
-      w.putUByte(0)
+      w.putUByte(h.unparsedBytes.length)
+      w.putBytes(h.unparsedBytes)
     }
   }
 
@@ -56,15 +57,20 @@ object HeaderSerializer extends ErgoSerializer[Header] {
 
     // For block version >= 2, a new byte encodes length of possible new fields.
     // If this byte > 0, we read new fields but do nothing, as semantics of the fields is not known.
-    if (version > Header.InitialVersion) {
+    val unparsedBytes = if (version > Header.InitialVersion) {
       val newFieldsSize = r.getUByte()
-      if (newFieldsSize > 0) {
+      if (newFieldsSize > 0 && version > Header.Interpreter60Version) {
+        // new bytes could be added only for block version >= 5
         r.getBytes(newFieldsSize)
+      } else {
+        Array.emptyByteArray
       }
+    } else {
+      Array.emptyByteArray
     }
 
     HeaderWithoutPow(version, parentId, ADProofsRoot, stateRoot, transactionsRoot, timestamp,
-      nBits, height, extensionHash, votes)
+      nBits, height, extensionHash, votes, unparsedBytes)
   }
 
   override def parse(r: Reader): Header = {

ergo-core/src/main/scala/org/ergoplatform/modifiers/history/header/HeaderWithoutPow.scala

@@ -17,19 +17,20 @@ class HeaderWithoutPow(val version: Header.Version, // 1 byte
                        val nBits: Long, //actually it is unsigned int
                        val height: Int,
                        val extensionRoot: Digest32,
-                       val votes: Array[Byte]) { //3 bytes
+                       val votes: Array[Byte], //3 bytes
+                       val unparsedBytes: Array[Byte]) {
   def toHeader(powSolution: AutolykosSolution, headerSize: Option[Int] = None): Header =
     Header(version, parentId, ADProofsRoot, stateRoot, transactionsRoot, timestamp,
-      nBits, height, extensionRoot, powSolution, votes, headerSize)
+      nBits, height, extensionRoot, powSolution, votes, unparsedBytes, headerSize)
 }
 
 object HeaderWithoutPow {
 
   def apply(version: Header.Version, parentId: ModifierId, ADProofsRoot: Digest32, stateRoot: ADDigest,
             transactionsRoot: Digest32, timestamp: Header.Timestamp, nBits: Long, height: Int,
-            extensionRoot: Digest32, votes: Array[Byte]): HeaderWithoutPow = {
+            extensionRoot: Digest32, votes: Array[Byte], unparsedBytes: Array[Byte]): HeaderWithoutPow = {
     new HeaderWithoutPow(version, parentId, ADProofsRoot, stateRoot, transactionsRoot, timestamp,
-      nBits, height, extensionRoot, votes)
+      nBits, height, extensionRoot, votes, unparsedBytes)
   }
 
 }

ergo-core/src/main/scala/org/ergoplatform/modifiers/history/header/PreGenesisHeader.scala

@@ -18,6 +18,7 @@ object PreGenesisHeader extends Header(
   extensionRoot = null,
   powSolution = null,
   votes = null,
+  unparsedBytes = Array.emptyByteArray,
   sizeOpt = None) {
 
   override def serializedId: Array[Byte] = idToBytes(Header.GenesisParentId)

ergo-core/src/test/scala/org/ergoplatform/network/HeaderSerializationSpecification.scala

@@ -43,7 +43,7 @@ class HeaderSerializationSpecification extends ErgoCorePropertyTest {
     val votes = Array[Byte](4, 3, 0)
 
     val h = Header(version, parentId, adProofsRoot, stateRoot, transactionsRoot, timestamp, nBits,
-                    height, extensionRoot, powSolution, votes)
+                    height, extensionRoot, powSolution, votes, Array.emptyByteArray)
 
     h.id shouldBe "8cf6dca6b9505243e36192fa107735024c0000cf4594b1daa2dc4e13ee86f26f"
 
@@ -141,7 +141,7 @@ class HeaderSerializationSpecification extends ErgoCorePropertyTest {
     val votes = Array[Byte](0, 0, 0)
 
     val h = Header(version, parentId, adProofsRoot, stateRoot, transactionsRoot, timestamp, nBits,
-      height, extensionRoot, powSolution, votes)
+      height, extensionRoot, powSolution, votes, Array.emptyByteArray)
 
     h.id shouldBe "f46c89e44f13a92d8409341490f97f05c85785fa8d2d2164332cc066eda95c39"
 

ergo-core/src/test/scala/org/ergoplatform/utils/generators/ErgoCoreGenerators.scala

@@ -172,6 +172,7 @@ object ErgoCoreGenerators {
     extensionHash,
     powSolution,
     Array.fill(3)(0: Byte),
+    Array.emptyByteArray,
     None
   )
 

src/main/scala/org/ergoplatform/mining/CandidateGenerator.scala

@@ -903,7 +903,8 @@ object CandidateGenerator extends ScorexLogging {
       candidate.nBits,
       height,
       extensionRoot,
-      candidate.votes
+      candidate.votes,
+      Array.emptyByteArray
     )
   }