fix(rpc): resolve EthTxIndex -1 sentinel before uint cast in receipt builder

CHANGELOG.md

@@ -22,7 +22,8 @@
 
 ### BUG FIXES
 
- [\#965](https://github.com/cosmos/evm/pull/965) Fix gas double charging on EVM calls in IBCOnTimeoutPacketCallback.
+- [\#1032](https://github.com/cosmos/evm/issues/1032) Resolve EthTxIndex -1 sentinel before uint cast in ReceiptsFromCometBlock, preventing transactionIndex overflow to MaxUint64.
+- [\#965](https://github.com/cosmos/evm/pull/965) Fix gas double charging on EVM calls in IBCOnTimeoutPacketCallback.
 - [\#869](https://github.com/cosmos/evm/pull/869) Fix erc20 IBC callbacks to check for native token transfer before parsing recipient.
 - [\#860](https://github.com/cosmos/evm/pull/860) Fix EIP-712 signature verification to use configured EVM chain ID instead of parsing cosmos chain ID string and replace legacytx.StdSignBytes with the aminojson sign mode handler.
 - [\#794](https://github.com/cosmos/evm/pull/794) Fix mempool.max-txs flag not using desired default of 0

rpc/backend/comet_to_eth.go

@@ -275,6 +275,13 @@ func (b *Backend) ReceiptsFromCometBlock(
 			return nil, fmt.Errorf("tx not found: hash=%s, error=%s", ethMsg.Hash(), err.Error())
 		}
 
+		// Resolve -1 sentinel: indexer hasn't assigned EthTxIndex yet.
+		// Use the loop index as the correct eth tx position,
+		// matching the existing fallback in GetTransactionByHash (tx_info.go).
+		if txResult.EthTxIndex == -1 {
+			txResult.EthTxIndex = int32(i) //#nosec G115 -- checked for int overflow already
+		}
+
 		cumulatedGasUsed += txResult.GasUsed
 
 		var effectiveGasPrice *big.Int

rpc/backend/tx_info_test.go

@@ -464,11 +464,12 @@ func TestReceiptsFromCometBlock(t *testing.T) {
 		TxsResults: []*abcitypes.ExecTxResult{{Code: 0, Data: encodedData}},
 	}
 	tcs := []struct {
-		name       string
-		ethTxIndex int32
+		name            string
+		ethTxIndex      int32
+		expectedTxIndex uint
 	}{
-		{"tx_with_index_5", 5},
-		{"tx_with_index_10", 10},
+		{"tx_with_valid_index", 5, 5},
+		{"tx_with_sentinel_index", -1, 0}, // -1 sentinel resolved to loop index
 	}
 	for _, tc := range tcs {
 		t.Run(tc.name, func(t *testing.T) {
@@ -492,9 +493,7 @@ func TestReceiptsFromCometBlock(t *testing.T) {
 			receipts, err := backend.ReceiptsFromCometBlock(rpctypes.NewContextWithHeight(1), resBlock, blockRes, msgs)
 			require.NoError(t, err)
 			require.Len(t, receipts, 1)
-			actualTxIndex := receipts[0].TransactionIndex
-			require.NotEqual(t, uint(0), actualTxIndex)
-			require.Equal(t, uint(tc.ethTxIndex), actualTxIndex) // #nosec G115
+			require.Equal(t, tc.expectedTxIndex, receipts[0].TransactionIndex)
 			require.Equal(t, msgs[0].Hash(), receipts[0].TxHash)
 			require.Equal(t, big.NewInt(height), receipts[0].BlockNumber)
 			require.Equal(t, ethtypes.ReceiptStatusSuccessful, receipts[0].Status)