[ETCM-921] rlp encoding and decoding test for Seq[SignedTransaction]

Author: strauss-m

src/test/scala/io/iohk/ethereum/domain/TransactionSpec.scala

@@ -10,6 +10,7 @@ import org.scalatestplus.scalacheck.ScalaCheckPropertyChecks
 import io.iohk.ethereum.ObjectGenerators
 import io.iohk.ethereum.crypto.ECDSASignature
 import io.iohk.ethereum.network.p2p.messages.BaseETH6XMessages.SignedTransactions
+import io.iohk.ethereum.rlp.RLPList
 import io.iohk.ethereum.security.SecureRandomBuilder
 import io.iohk.ethereum.utils.Config
 import io.iohk.ethereum.utils.Hex
@@ -27,7 +28,7 @@ class TransactionSpec
     forAll(signedTxGen(secureRandom, None)) { (originalSignedTransaction: SignedTransaction) =>
       // encode it
       import SignedTransactions.SignedTransactionEnc
-      val encodedSignedTransaction = originalSignedTransaction.toBytes
+      val encodedSignedTransaction: Array[Byte] = originalSignedTransaction.toBytes
 
       // decode it
       import SignedTransactions.SignedTransactionDec
@@ -37,6 +38,40 @@ class TransactionSpec
     }
   }
 
+  "rlp encoding then decoding transactions sequence" should "give back the initial transactions sequence" in {
+
+    forAll(signedTxSeqGen(2, secureRandom, None)) { (originalSignedTransactionSeq: Seq[SignedTransaction]) =>
+      // encode it
+      import SignedTransactions.SignedTransactionsEnc
+
+      // SignedTransactionsEnc is the Sequence version of SignedTransactionEnc
+      // the SignedTransactionsEnc.toBytes calls
+      // -> SignedTransactionsEnc.toRLPEncodable which maps over
+      // -> SignedTransactionEnc.toRLPEncodable (single signed transaction encoder)
+      // without going through the SignedTransactionEnc.toByte, which is the actual part where the 01 prefix is inserted
+      val encodedSignedTransactionSeq: Array[Byte] = SignedTransactions(originalSignedTransactionSeq).toBytes
+
+      // decode it
+      import SignedTransactions.SignedTransactionsDec
+      // likewise, the SignedTransactionsDec.toSignedTransactions maps over
+      // -> SignedTransactionRlpEncodableDec.toSignedTransaction (single signed transaction)
+      // while ignoring the SignedTransactionDec(Array[Byte]), which is responsible to parse the prefix if available
+      val SignedTransactions(decodedSignedTransactionSeq) = encodedSignedTransactionSeq.toSignedTransactions
+
+      // The test is working because both encoding and decoding are skipping the prefix part,
+      // and the rlp encoded transaction is different enough to recognize a LegacyTransaction from a TX1
+
+      // I see two problems:
+      // - the encoding is not compatible with other clients
+      // - this is not working for receipt, where legacy and tx1 receipt payload are the same. As such we can't
+      // distinguish which one it is without the prefix
+
+      // The root cause seems to be that the prefix stuff is done on a byte[] level,
+      // whereas RLPList are working on RLPEncodable
+      decodedSignedTransactionSeq shouldEqual originalSignedTransactionSeq
+    }
+  }
+
   "Transaction type 01" should "be correctly serialized to rlp" in {
 
     // binary values have be taken directly from core-geth own tests