[Sei] fix ante decorators

app/antedecorators/gasless.go

@@ -21,14 +21,27 @@ func NewGaslessDecorator(wrapped []sdk.AnteDecorator, oracleKeeper oraclekeeper.
 func (gd GaslessDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (newCtx sdk.Context, err error) {
 	if !isTxGasless(tx, ctx, gd.oracleKeeper) {
 		// if not gasless, then we use the wrappers
-		return sdk.ChainAnteDecorators(gd.wrapped...)(ctx, tx, simulate)
+
+		// AnteHandle always takes a `next` so we need a no-op to execute only one handler at a time
+		terminatorHandler := func(ctx sdk.Context, _ sdk.Tx, _ bool) (sdk.Context, error) {
+			return ctx, nil
+		}
+		// iterating instead of recursing the handler for readability
+		for _, handler := range gd.wrapped {
+			ctx, err = handler.AnteHandle(ctx, tx, simulate, terminatorHandler)
+		}
+		return next(ctx, tx, simulate)
 	}
 	gaslessMeter := sdk.NewInfiniteGasMeter()
 
 	return next(ctx.WithGasMeter(gaslessMeter), tx, simulate)
 }
 
 func isTxGasless(tx sdk.Tx, ctx sdk.Context, oracleKeeper oraclekeeper.Keeper) bool {
+	if len(tx.GetMsgs()) == 0 {
+		// empty TX shouldn't be gasless
+		return false
+	}
 	for _, msg := range tx.GetMsgs() {
 		switch m := msg.(type) {
 		case *dextypes.MsgPlaceOrders:

app/antedecorators/gasless_test.go

@@ -0,0 +1,55 @@
+package antedecorators_test
+
+import (
+	"fmt"
+	"testing"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/sei-protocol/sei-chain/app/antedecorators"
+	oraclekeeper "github.com/sei-protocol/sei-chain/x/oracle/keeper"
+	"github.com/stretchr/testify/require"
+)
+
+var output = ""
+
+type FakeAnteDecoratorOne struct{}
+
+func (ad FakeAnteDecoratorOne) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (newCtx sdk.Context, err error) {
+	output = fmt.Sprintf("%sone", output)
+	return next(ctx, tx, simulate)
+}
+
+type FakeAnteDecoratorTwo struct{}
+
+func (ad FakeAnteDecoratorTwo) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (newCtx sdk.Context, err error) {
+	output = fmt.Sprintf("%stwo", output)
+	return next(ctx, tx, simulate)
+}
+
+type FakeAnteDecoratorThree struct{}
+
+func (ad FakeAnteDecoratorThree) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (newCtx sdk.Context, err error) {
+	output = fmt.Sprintf("%sthree", output)
+	return next(ctx, tx, simulate)
+}
+
+type FakeTx struct{}
+
+func (tx FakeTx) GetMsgs() []sdk.Msg {
+	return []sdk.Msg{}
+}
+
+func (tx FakeTx) ValidateBasic() error {
+	return nil
+}
+
+func TestGaslessDecorator(t *testing.T) {
+	anteDecorators := []sdk.AnteDecorator{
+		FakeAnteDecoratorOne{},
+		antedecorators.NewGaslessDecorator([]sdk.AnteDecorator{FakeAnteDecoratorTwo{}}, oraclekeeper.Keeper{}),
+		FakeAnteDecoratorThree{},
+	}
+	chainedHandler := sdk.ChainAnteDecorators(anteDecorators...)
+	chainedHandler(sdk.Context{}, FakeTx{}, false)
+	require.Equal(t, "onetwothree", output)
+}