adding changes for burn functionality on spread fee

proto/terra/market/v1beta1/market.proto

@@ -21,4 +21,9 @@ message Params {
     (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
     (gogoproto.nullable)   = false
   ];
+  bytes  fee_burn_ratio = 4 [
+    (gogoproto.moretags)   = "yaml:\"fee_burn_ratio\"",
+    (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
+    (gogoproto.nullable)   = false
+  ];
 }

x/market/keeper/msg_server.go

@@ -2,6 +2,7 @@ package keeper
 
 import (
 	"context"
+	treasury "github.com/classic-terra/core/v2/x/treasury/types"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
 
@@ -121,12 +122,24 @@ func (k msgServer) handleSwapRequest(ctx sdk.Context,
 		return nil, err
 	}
 
-	// Send swap fee to oracle account
+	// Send swap fee to oracle account based on percentage, burn the rest
 	if feeCoin.IsPositive() {
-		feeCoins := sdk.NewCoins(feeCoin)
-		err = k.BankKeeper.SendCoinsFromModuleToModule(ctx, types.ModuleName, oracletypes.ModuleName, feeCoins)
-		if err != nil {
-			return nil, err
+		var sendCoins sdk.Coins
+		burnCoins := sdk.NewCoins(sdk.NewCoin(feeCoin.GetDenom(), sdk.NewDec(feeCoin.Amount.Int64()).Mul(k.FeeBurnRatio(ctx)).TruncateInt()))
+		if !burnCoins.IsZero() {
+			sendCoins = sdk.NewCoins(feeCoin.Sub(burnCoins[0]))
+			err = k.BankKeeper.SendCoinsFromModuleToModule(ctx, types.ModuleName, treasury.BurnModuleName, burnCoins)
+			if err != nil {
+				return nil, err
+			}
+		} else {
+			sendCoins = sdk.NewCoins(feeCoin)
+		}
+		if !sendCoins.IsZero() {
+			err = k.BankKeeper.SendCoinsFromModuleToModule(ctx, types.ModuleName, oracletypes.ModuleName, sendCoins)
+			if err != nil {
+				return nil, err
+			}
 		}
 	}
 

x/market/keeper/params.go

@@ -19,6 +19,12 @@ func (k Keeper) MinStabilitySpread(ctx sdk.Context) (res sdk.Dec) {
 	return
 }
 
+// FeeBurnRatio represents the percentage of spread fee burnt during swaps to / from Luna.
+func (k Keeper) FeeBurnRatio(ctx sdk.Context) (res sdk.Dec) {
+	k.paramSpace.Get(ctx, types.KeyFeeBurnRatio, &res)
+	return
+}
+
 // PoolRecoveryPeriod is the period required to recover Terra&Luna Pools to the MintBasePool & BurnBasePool
 func (k Keeper) PoolRecoveryPeriod(ctx sdk.Context) (res uint64) {
 	k.paramSpace.Get(ctx, types.KeyPoolRecoveryPeriod, &res)

x/market/types/genesis_test.go

@@ -3,23 +3,63 @@ package types
 import (
 	"testing"
 
-	"github.com/stretchr/testify/require"
-
 	sdk "github.com/cosmos/cosmos-sdk/types"
 )
 
 func TestGenesisValidation(t *testing.T) {
-	genState := DefaultGenesisState()
-	require.NoError(t, ValidateGenesis(genState))
-
-	genState.Params.BasePool = sdk.NewDec(-1)
-	require.Error(t, ValidateGenesis(genState))
 
-	genState = DefaultGenesisState()
-	genState.Params.PoolRecoveryPeriod = 0
-	require.Error(t, ValidateGenesis(genState))
+	tests := []struct {
+		name     string
+		GenState func() *GenesisState
+		wantErr  bool
+	}{
+		{
+			name:     "valid state",
+			GenState: DefaultGenesisState,
+			wantErr:  false,
+		},
+		{
+			name: "invalid BasePool state",
+			GenState: func() *GenesisState {
+				genState := DefaultGenesisState()
+				genState.Params.BasePool = sdk.NewDec(-1)
+				return genState
+			},
+			wantErr: true,
+		},
+		{
+			name: "invalid PoolRecoveryPeriod state",
+			GenState: func() *GenesisState {
+				genState := DefaultGenesisState()
+				genState.Params.PoolRecoveryPeriod = 0
+				return genState
+			},
+			wantErr: true,
+		},
+		{
+			name: "invalid MinStabilitySpread state",
+			GenState: func() *GenesisState {
+				genState := DefaultGenesisState()
+				genState.Params.MinStabilitySpread = sdk.NewDec(-1)
+				return genState
+			},
+			wantErr: true,
+		},
+		{
+			name: "invalid FeeBurnRatio state",
+			GenState: func() *GenesisState {
+				genState := DefaultGenesisState()
+				genState.Params.FeeBurnRatio = sdk.NewDec(-1)
+				return genState
+			},
+			wantErr: true,
+		},
+	}
 
-	genState = DefaultGenesisState()
-	genState.Params.MinStabilitySpread = sdk.NewDec(-1)
-	require.Error(t, ValidateGenesis(genState))
+	for _, tt := range tests {
+		genState := tt.GenState()
+		if err := ValidateGenesis(genState); (err != nil) != tt.wantErr {
+			t.Errorf("expected wantErr = %v got %v", tt.wantErr, err != nil)
+		}
+	}
 }