rpc: make trace transaction api work with batch tx (#907)

* make trace transaction api work with batch tx

Closes: #906

fix linter

* review suggestion

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

rpc/ethereum/namespaces/debug/api.go

@@ -89,13 +89,17 @@ func (a *API) TraceTransaction(hash common.Hash, config *evmtypes.TraceConfig) (
 		return nil, err
 	}
 
+	msgIndex, _ := rpctypes.FindTxAttributes(transaction.TxResult.Events, hash.Hex())
+	if msgIndex < 0 {
+		return nil, fmt.Errorf("ethereum tx not found in msgs: %s", hash.Hex())
+	}
+
 	// check tx index is not out of bound
 	if uint32(len(blk.Block.Txs)) < transaction.Index {
 		a.logger.Debug("tx index out of bounds", "index", transaction.Index, "hash", hash.String(), "height", blk.Block.Height)
 		return nil, fmt.Errorf("transaction not included in block %v", blk.Block.Height)
 	}
 
-	// nolint: prealloc
 	var predecessors []*evmtypes.MsgEthereumTx
 	for _, txBz := range blk.Block.Txs[:transaction.Index] {
 		tx, err := a.clientCtx.TxConfig.TxDecoder()(txBz)
@@ -103,13 +107,14 @@ func (a *API) TraceTransaction(hash common.Hash, config *evmtypes.TraceConfig) (
 			a.logger.Debug("failed to decode transaction in block", "height", blk.Block.Height, "error", err.Error())
 			continue
 		}
-		msg := tx.GetMsgs()[0]
+		for _, msg := range tx.GetMsgs() {
-		ethMsg, ok := msg.(*evmtypes.MsgEthereumTx)
+			ethMsg, ok := msg.(*evmtypes.MsgEthereumTx)
-		if !ok {
+			if !ok {
-			continue
+				continue
-		}
+			}
 
-		predecessors = append(predecessors, ethMsg)
+			predecessors = append(predecessors, ethMsg)
+		}
 	}
 
 	tx, err := a.clientCtx.TxConfig.TxDecoder()(transaction.Tx)
@@ -118,7 +123,16 @@ func (a *API) TraceTransaction(hash common.Hash, config *evmtypes.TraceConfig) (
 		return nil, err
 	}
 
-	ethMessage, ok := tx.GetMsgs()[0].(*evmtypes.MsgEthereumTx)
+	// add predecessor messages in current cosmos tx
+	for i := 0; i < msgIndex; i++ {
+		ethMsg, ok := tx.GetMsgs()[i].(*evmtypes.MsgEthereumTx)
+		if !ok {
+			continue
+		}
+		predecessors = append(predecessors, ethMsg)
+	}
+
+	ethMessage, ok := tx.GetMsgs()[msgIndex].(*evmtypes.MsgEthereumTx)
 	if !ok {
 		a.logger.Debug("invalid transaction type", "type", fmt.Sprintf("%T", tx))
 		return nil, fmt.Errorf("invalid transaction type %T", tx)
@@ -209,7 +223,6 @@ func (a *API) traceBlock(height rpctypes.BlockNumber, config *evmtypes.TraceConf
 
 	txDecoder := a.clientCtx.TxConfig.TxDecoder()
 
-	// nolint: prealloc
 	var txsMessages []*evmtypes.MsgEthereumTx
 	for i, tx := range txs {
 		decodedTx, err := txDecoder(tx)
@@ -218,16 +231,14 @@ func (a *API) traceBlock(height rpctypes.BlockNumber, config *evmtypes.TraceConf
 			continue
 		}
 
-		messages := decodedTx.GetMsgs()
+		for _, msg := range decodedTx.GetMsgs() {
-		if len(messages) == 0 {
+			ethMessage, ok := msg.(*evmtypes.MsgEthereumTx)
-			continue
+			if !ok {
+				// Just considers Ethereum transactions
+				continue
+			}
+			txsMessages = append(txsMessages, ethMessage)
 		}
-		ethMessage, ok := messages[0].(*evmtypes.MsgEthereumTx)
-		if !ok {
-			// Just considers Ethereum transactions
-			continue
-		}
-		txsMessages = append(txsMessages, ethMessage)
 	}
 
 	// minus one to get the context at the beginning of the block

rpc/ethereum/namespaces/eth/api.go

@@ -699,12 +699,15 @@ func (e *PublicAPI) getTransactionByBlockAndIndex(block *tmrpctypes.ResultBlock,
 			e.logger.Debug("invalid ethereum tx", "height", block.Block.Header, "index", idx)
 			return nil, nil
 		}
-		if len(tx.GetMsgs()) != 1 {
+		// find msg index in events
+		msgIndex := rpctypes.FindTxAttributesByIndex(res.TxResult.Events, uint64(idx))
+		if msgIndex < 0 {
 			e.logger.Debug("invalid ethereum tx", "height", block.Block.Header, "index", idx)
 			return nil, nil
 		}
 		var ok bool
-		msg, ok = tx.GetMsgs()[0].(*evmtypes.MsgEthereumTx)
+		// msgIndex is inferred from tx events, should be within bound.
+		msg, ok = tx.GetMsgs()[msgIndex].(*evmtypes.MsgEthereumTx)
 		if !ok {
 			e.logger.Debug("invalid ethereum tx", "height", block.Block.Header, "index", idx)
 			return nil, nil

rpc/ethereum/types/utils.go

@@ -282,6 +282,31 @@ func FindTxAttributes(events []abci.Event, txHash string) (int, map[string]strin
 	return -1, nil
 }
 
+// FindTxAttributesByIndex search the msg in tx events by txIndex
+// returns the msgIndex, returns -1 if not found.
+func FindTxAttributesByIndex(events []abci.Event, txIndex uint64) int {
+	strIndex := []byte(strconv.FormatUint(txIndex, 10))
+	txIndexKey := []byte(evmtypes.AttributeKeyTxIndex)
+	msgIndex := -1
+	for _, event := range events {
+		if event.Type != evmtypes.EventTypeEthereumTx {
+			continue
+		}
+
+		msgIndex++
+
+		value := FindAttribute(event.Attributes, txIndexKey)
+		if !bytes.Equal(value, strIndex) {
+			continue
+		}
+
+		// found, convert attributes to map for later lookup
+		return msgIndex
+	}
+	// not found
+	return -1
+}
+
 // FindAttribute find event attribute with specified key, if not found returns nil.
 func FindAttribute(attrs []abci.EventAttribute, key []byte) []byte {
 	for _, attr := range attrs {