don't scale-encode witness data

Align raw TX format to the genvm: `raw = <tx bytes> | <witness data>`.

vm/core/sign.go

@@ -28,10 +28,6 @@ func SignedTx(tx *Tx, genesisID types.Hash20, pk signing.PrivateKey) ([]byte, er
 		return nil, fmt.Errorf("encoding deploy TX: %w", err)
 	}
 
-	sig := SignRawTx(encodedTx.Bytes(), genesisID, pk)
-	if _, err := scale.EncodeByteSlice(enc, sig); err != nil {
-		return nil, fmt.Errorf("encoding TX signature: %w", err)
-	}
-
+	encodedTx.Write(SignRawTx(encodedTx.Bytes(), genesisID, pk))
 	return encodedTx.Bytes(), nil
 }

vm/sdk/multisig/tx.go

@@ -45,20 +45,15 @@ func (a *SignatureAggregator) Add(ref uint8, sig core.Signature) {
 
 // Raw returns full raw transaction including payload and signatures.
 func (a *SignatureAggregator) Raw() []byte {
-	var buf bytes.Buffer
-	enc := scale.NewEncoder(&buf)
+	buf := bytes.NewBuffer(a.unsigned)
+	enc := scale.NewEncoder(buf)
 	keys := slices.Sorted(maps.Keys(a.parts))
 	for _, ref := range keys {
 		if err := enc.Encode(a.parts[ref]); err != nil {
 			panic(err)
 		}
 	}
-	rawTxBuf := bytes.NewBuffer(a.unsigned)
-	enc = scale.NewEncoder(rawTxBuf)
-	if err := enc.Encode(buf.Bytes()); err != nil {
-		panic(err)
-	}
-	return rawTxBuf.Bytes()
+	return buf.Bytes()
 }
 
 func EncodeSpawnArgs(required uint8, pubkeys []core.PublicKey) []byte {

vm/vm.go

@@ -5,7 +5,6 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"io"
 	"time"
 
 	gossamerScale "github.com/ChainSafe/gossamer/pkg/scale"
@@ -537,14 +536,6 @@ func parse(
 	if tx.Version != 1 {
 		return nil, nil, fmt.Errorf("%w: %d", errWrongVersion, tx.Version)
 	}
-	// Decode witness data
-	witnessData, _, err := scale.DecodeByteSlice(decoder)
-	switch {
-	case errors.Is(err, io.EOF):
-		logger.Debug("witness data is empty")
-	case err != nil:
-		return nil, nil, fmt.Errorf("decoding witness data: %w", err)
-	}
 
 	ctx, err := core.New(cfg.GenesisID, lid, tx.Principal, loader, logger)
 	if err != nil {
@@ -602,7 +593,7 @@ func parse(
 	}
 	ctx.TxPayload = tx.Payload
 	ctx.TxData = raw[:n]
-	ctx.WitnessData = witnessData
+	ctx.WitnessData = raw[n:]
 
 	// At this point we've established that the transaction is correctly formed, but we haven't
 	// yet attempted to validate the signature. That happens later in Verify().
@@ -616,10 +607,10 @@ func parse(
 	logger.Debug(
 		"calculating max gas",
 		zap.Int("payload len", len(tx.Payload)),
-		zap.Int("witness data len", len(witnessData)),
+		zap.Int("witness data len", len(ctx.WitnessData)),
 	)
 	ctx.Header.MaxGas = core.MaxGas(
-		estimatedStateSize + max(len(tx.Payload), 6) - 6 + len(witnessData),
+		estimatedStateSize + max(len(tx.Payload), 6) - 6 + len(ctx.WitnessData),
 	) // skip bytes for method selector
 	ctx.Header.Principal = tx.Principal
 	ctx.Header.GasPrice = tx.Metadata.GasPrice