refactor: max supply check (#3073)

x/fungible/keeper/deposits_test.go

@@ -437,6 +437,10 @@ func TestKeeper_DepositCoinZeta(t *testing.T) {
 		b := sdkk.BankKeeper.GetBalance(ctx, zetaToAddress, config.BaseDenom)
 		require.Equal(t, int64(0), b.Amount.Int64())
 		errorMint := errors.New("", 1, "error minting coins")
+
+		bankMock.On("GetSupply", ctx, mock.Anything, mock.Anything).
+			Return(sdk.NewCoin(config.BaseDenom, sdk.NewInt(0))).
+			Once()
 		bankMock.On("MintCoins", ctx, types.ModuleName, mock.Anything).Return(errorMint).Once()
 		err := k.DepositCoinZeta(ctx, to, amount)
 		require.ErrorIs(t, err, errorMint)

x/fungible/keeper/zeta.go

@@ -1,6 +1,7 @@
 package keeper
 
 import (
+	"errors"
 	"math/big"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
@@ -9,9 +10,24 @@ import (
 	"github.com/zeta-chain/node/x/fungible/types"
 )
 
+// ZETAMaxSupplyStr is the maximum mintable ZETA in the fungible module
+// 1.85 billion ZETA
+const ZETAMaxSupplyStr = "1850000000000000000000000000"
+
 // MintZetaToEVMAccount mints ZETA (gas token) to the given address
 // NOTE: this method should be used with a temporary context, and it should not be committed if the method returns an error
 func (k *Keeper) MintZetaToEVMAccount(ctx sdk.Context, to sdk.AccAddress, amount *big.Int) error {
+	zetaMaxSupply, ok := sdk.NewIntFromString(ZETAMaxSupplyStr)
+	if !ok {
+		return errors.New("failed to parse ZETA max supply")
+	}
+
+	// Check if the max supply is reached
+	supply := k.bankKeeper.GetSupply(ctx, config.BaseDenom)
+	if supply.Amount.Add(sdk.NewIntFromBigInt(amount)).GT(zetaMaxSupply) {
+		return types.ErrMaxSupplyReached
+	}
+
 	coins := sdk.NewCoins(sdk.NewCoin(config.BaseDenom, sdk.NewIntFromBigInt(amount)))
 	// Mint coins
 	if err := k.bankKeeper.MintCoins(ctx, types.ModuleName, coins); err != nil {
@@ -23,6 +39,17 @@ func (k *Keeper) MintZetaToEVMAccount(ctx sdk.Context, to sdk.AccAddress, amount
 }
 
 func (k *Keeper) MintZetaToFungibleModule(ctx sdk.Context, amount *big.Int) error {
+	zetaMaxSupply, ok := sdk.NewIntFromString(ZETAMaxSupplyStr)
+	if !ok {
+		return errors.New("failed to parse ZETA max supply")
+	}
+
+	// Check if the max supply is reached
+	supply := k.bankKeeper.GetSupply(ctx, config.BaseDenom)
+	if supply.Amount.Add(sdk.NewIntFromBigInt(amount)).GT(zetaMaxSupply) {
+		return types.ErrMaxSupplyReached
+	}
+
 	coins := sdk.NewCoins(sdk.NewCoin(config.BaseDenom, sdk.NewIntFromBigInt(amount)))
 	// Mint coins
 	return k.bankKeeper.MintCoins(ctx, types.ModuleName, coins)

x/fungible/keeper/zeta_test.go

@@ -2,6 +2,7 @@ package keeper_test
 
 import (
 	"errors"
+	"github.com/stretchr/testify/mock"
 	"math/big"
 	"testing"
 
@@ -11,6 +12,7 @@ import (
 	"github.com/zeta-chain/node/cmd/zetacored/config"
 	testkeeper "github.com/zeta-chain/node/testutil/keeper"
 	"github.com/zeta-chain/node/testutil/sample"
+	"github.com/zeta-chain/node/x/fungible/keeper"
 	"github.com/zeta-chain/node/x/fungible/types"
 )
 
@@ -29,13 +31,56 @@ func TestKeeper_MintZetaToEVMAccount(t *testing.T) {
 		require.True(t, bal.Amount.Equal(sdk.NewInt(42)))
 	})
 
+	t.Run("mint the token to reach max supply", func(t *testing.T) {
+		k, ctx, sdkk, _ := testkeeper.FungibleKeeper(t)
+		k.GetAuthKeeper().GetModuleAccount(ctx, types.ModuleName)
+
+		acc := sample.Bech32AccAddress()
+		bal := sdkk.BankKeeper.GetBalance(ctx, acc, config.BaseDenom)
+		require.True(t, bal.IsZero())
+
+		zetaMaxSupply, ok := sdk.NewIntFromString(keeper.ZETAMaxSupplyStr)
+		require.True(t, ok)
+
+		supply := sdkk.BankKeeper.GetSupply(ctx, config.BaseDenom).Amount
+
+		newAmount := zetaMaxSupply.Sub(supply)
+
+		err := k.MintZetaToEVMAccount(ctx, acc, newAmount.BigInt())
+		require.NoError(t, err)
+		bal = sdkk.BankKeeper.GetBalance(ctx, acc, config.BaseDenom)
+		require.True(t, bal.Amount.Equal(newAmount))
+	})
+
+	t.Run("can't mint more than max supply", func(t *testing.T) {
+		k, ctx, sdkk, _ := testkeeper.FungibleKeeper(t)
+		k.GetAuthKeeper().GetModuleAccount(ctx, types.ModuleName)
+
+		acc := sample.Bech32AccAddress()
+		bal := sdkk.BankKeeper.GetBalance(ctx, acc, config.BaseDenom)
+		require.True(t, bal.IsZero())
+
+		zetaMaxSupply, ok := sdk.NewIntFromString(keeper.ZETAMaxSupplyStr)
+		require.True(t, ok)
+
+		supply := sdkk.BankKeeper.GetSupply(ctx, config.BaseDenom).Amount
+
+		newAmount := zetaMaxSupply.Sub(supply).Add(sdk.NewInt(1))
+
+		err := k.MintZetaToEVMAccount(ctx, acc, newAmount.BigInt())
+		require.ErrorIs(t, err, types.ErrMaxSupplyReached)
+	})
+
 	coins42 := sdk.NewCoins(sdk.NewCoin(config.BaseDenom, sdk.NewInt(42)))
 
 	t.Run("should fail if minting fail", func(t *testing.T) {
 		k, ctx := testkeeper.FungibleKeeperAllMocks(t)
 
 		mockBankKeeper := testkeeper.GetFungibleBankMock(t, k)
 
+		mockBankKeeper.On("GetSupply", ctx, mock.Anything, mock.Anything).
+			Return(sdk.NewCoin(config.BaseDenom, sdk.NewInt(0))).
+			Once()
 		mockBankKeeper.On(
 			"MintCoins",
 			ctx,
@@ -55,6 +100,9 @@ func TestKeeper_MintZetaToEVMAccount(t *testing.T) {
 
 		mockBankKeeper := testkeeper.GetFungibleBankMock(t, k)
 
+		mockBankKeeper.On("GetSupply", ctx, mock.Anything, mock.Anything).
+			Return(sdk.NewCoin(config.BaseDenom, sdk.NewInt(0))).
+			Once()
 		mockBankKeeper.On(
 			"MintCoins",
 			ctx,
@@ -76,3 +124,33 @@ func TestKeeper_MintZetaToEVMAccount(t *testing.T) {
 		mockBankKeeper.AssertExpectations(t)
 	})
 }
+
+func TestKeeper_MintZetaToFungibleModule(t *testing.T) {
+	t.Run("should mint the token in the specified balance", func(t *testing.T) {
+		k, ctx, sdkk, _ := testkeeper.FungibleKeeper(t)
+		acc := k.GetAuthKeeper().GetModuleAccount(ctx, types.ModuleName).GetAddress()
+
+		bal := sdkk.BankKeeper.GetBalance(ctx, acc, config.BaseDenom)
+		require.True(t, bal.IsZero())
+
+		err := k.MintZetaToEVMAccount(ctx, acc, big.NewInt(42))
+		require.NoError(t, err)
+		bal = sdkk.BankKeeper.GetBalance(ctx, acc, config.BaseDenom)
+		require.True(t, bal.Amount.Equal(sdk.NewInt(42)))
+	})
+
+	t.Run("can't mint more than max supply", func(t *testing.T) {
+		k, ctx, sdkk, _ := testkeeper.FungibleKeeper(t)
+		k.GetAuthKeeper().GetModuleAccount(ctx, types.ModuleName)
+
+		zetaMaxSupply, ok := sdk.NewIntFromString(keeper.ZETAMaxSupplyStr)
+		require.True(t, ok)
+
+		supply := sdkk.BankKeeper.GetSupply(ctx, config.BaseDenom).Amount
+
+		newAmount := zetaMaxSupply.Sub(supply).Add(sdk.NewInt(1))
+
+		err := k.MintZetaToFungibleModule(ctx, newAmount.BigInt())
+		require.ErrorIs(t, err, types.ErrMaxSupplyReached)
+	})
+}

x/fungible/keeper/zevm_message_passing_test.go

@@ -146,6 +146,9 @@ func TestKeeper_ZEVMDepositAndCallContract(t *testing.T) {
 		})
 		require.NoError(t, err)
 		errorMint := errors.New("", 10, "error minting coins")
+		bankMock.On("GetSupply", ctx, mock.Anything, mock.Anything).
+			Return(sdk.NewCoin(config.BaseDenom, sdk.NewInt(0))).
+			Once()
 		bankMock.On("MintCoins", ctx, types.ModuleName, mock.Anything).Return(errorMint).Once()
 
 		_, err = k.ZETADepositAndCallContract(
@@ -296,6 +299,9 @@ func TestKeeper_ZEVMRevertAndCallContract(t *testing.T) {
 		})
 		require.NoError(t, err)
 		errorMint := errors.New("", 101, "error minting coins")
+		bankMock.On("GetSupply", ctx, mock.Anything, mock.Anything).
+			Return(sdk.NewCoin(config.BaseDenom, sdk.NewInt(0))).
+			Once()
 		bankMock.On("MintCoins", ctx, types.ModuleName, mock.Anything).Return(errorMint).Once()
 
 		_, err = k.ZETARevertAndCallContract(

x/fungible/types/errors.go

@@ -34,4 +34,5 @@ var (
 	ErrZRC20NilABI             = cosmoserrors.Register(ModuleName, 1132, "ZRC20 ABI is nil")
 	ErrZeroAddress             = cosmoserrors.Register(ModuleName, 1133, "address cannot be zero")
 	ErrInvalidAmount           = cosmoserrors.Register(ModuleName, 1134, "invalid amount")
+	ErrMaxSupplyReached        = cosmoserrors.Register(ModuleName, 1135, "max supply reached")
 )

x/fungible/types/expected_keepers.go

@@ -33,6 +33,7 @@ type BankKeeper interface {
 		amt sdk.Coins,
 	) error
 	MintCoins(ctx sdk.Context, moduleName string, amt sdk.Coins) error
+	GetSupply(ctx sdk.Context, denom string) sdk.Coin
 }
 
 type ObserverKeeper interface {