Problem: disallow same sender tx appear in the same tx after contract

CHANGELOG.md

@@ -79,6 +79,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (rpc) [#558](https://github.com/crypto-org-chain/ethermint/pull/558) New tracer in predecessors to trace balance correctly when `debug_traceTransaction`.
 * (rpc) [#559](https://github.com/crypto-org-chain/ethermint/pull/559) Use basefee of transaction height instead of minus one height when `debug_traceTransaction`.
 * (rpc) [#562](https://github.com/crypto-org-chain/ethermint/pull/562) Fix nil pointer panic with legacy transaction format.
+* (ante) [#566](https://github.com/crypto-org-chain/ethermint/pull/566) Disallow same sender tx appear after contract creation in the same batch tx.
 
 ### Improvements
 

app/ante/eth.go

@@ -311,3 +311,38 @@ func CheckAndSetEthSenderNonce(
 
 	return nil
 }
+
+// DetectContractCreationBatchTx returns error if same same transaction appear after contract creation tx in the same
+// batch
+func DetectContractCreationBatchTx(ctx sdk.Context, tx sdk.Tx) error {
+	if !ctx.IsCheckTx() {
+		// only check in mempool logic
+		return nil
+	}
+
+	if len(tx.GetMsgs()) <= 1 {
+		return nil
+	}
+
+	senders := make(map[string]struct{})
+	for _, msg := range tx.GetMsgs() {
+		msgEthTx, ok := msg.(*evmtypes.MsgEthereumTx)
+		if !ok {
+			return errorsmod.Wrapf(errortypes.ErrUnknownRequest, "invalid message type %T, expected %T", msg, (*evmtypes.MsgEthereumTx)(nil))
+		}
+
+		sender := string(msgEthTx.GetSender().Bytes())
+		if _, ok := senders[sender]; ok {
+			return errorsmod.Wrapf(
+				errortypes.ErrInvalidRequest,
+				"same sender included after contract creation in the batch transaction",
+			)
+		}
+
+		if msgEthTx.AsTransaction().To() == nil {
+			senders[sender] = struct{}{}
+		}
+	}
+
+	return nil
+}

app/ante/handler_options.go

@@ -149,6 +149,11 @@ func newEthAnteHandler(options HandlerOptions) sdk.AnteHandler {
 			return ctx, err
 		}
 
+		// reject contract creation tx in batch tx
+		if err := DetectContractCreationBatchTx(ctx, tx); err != nil {
+			return ctx, err
+		}
+
 		extraDecorators := options.ExtraDecorators
 		if options.PendingTxListener != nil {
 			extraDecorators = append(extraDecorators, newTxListenerDecorator(options.PendingTxListener))