add future height check for get_transaction_count

rpc/backend/account_info.go

@@ -22,6 +22,7 @@ import (
 
 	sdkmath "cosmossdk.io/math"
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
@@ -187,14 +188,26 @@ func (b *Backend) GetBalance(address common.Address, blockNrOrHash rpctypes.Bloc
 
 // GetTransactionCount returns the number of transactions at the given address up to the given block number.
 func (b *Backend) GetTransactionCount(address common.Address, blockNum rpctypes.BlockNumber) (*hexutil.Uint64, error) {
+	n := hexutil.Uint64(0)
+	bn, err := b.BlockNumber()
+	if err != nil {
+		return &n, err
+	}
+	height := blockNum.Int64()
+	currentHeight := int64(bn)
+	if height > currentHeight {
+		return &n, sdkerrors.Wrap(
+			sdkerrors.ErrInvalidHeight,
+			"cannot query with height in the future; please provide a valid height",
+		)
+	}
 	// Get nonce (sequence) from account
 	from := sdk.AccAddress(address.Bytes())
 	accRet := b.clientCtx.AccountRetriever
 
-	err := accRet.EnsureExists(b.clientCtx, from)
+	err = accRet.EnsureExists(b.clientCtx, from)
 	if err != nil {
 		// account doesn't exist yet, return 0
-		n := hexutil.Uint64(0)
 		return &n, nil
 	}
 
@@ -204,6 +217,6 @@ func (b *Backend) GetTransactionCount(address common.Address, blockNum rpctypes.
 		return nil, err
 	}
 
-	n := hexutil.Uint64(nonce)
+	n = hexutil.Uint64(nonce)
 	return &n, nil
 }