fix: remove minimum rent exempt check for SPL token withdrawals (#3374)

* remove minimum rent exempt check for SPL tokens

* lower default SPL withdraw amount in E2E to ensure min rent exempt is not checked

* add changelog entry

* add comment to explain why rent exempt check is only applied to Solana gas token

changelog.md

@@ -8,6 +8,10 @@
 * [3360](https://github.com/zeta-chain/node/pull/3360) - update protocol contract imports using consolidated path
 * [3349](https://github.com/zeta-chain/node/pull/3349) - implement new bitcoin rpc in zetaclient with improved performance and observability
 
+### Fixes
+
+* [3374](https://github.com/zeta-chain/node/pull/3374) - remove minimum rent exempt check for SPL token withdrawals
+
 ## v25.0.0
 
 ## Unreleased

e2e/e2etests/e2etests.go

@@ -453,7 +453,7 @@ var AllE2ETests = []runner.E2ETest{
 		TestSPLWithdrawName,
 		"withdraw SPL from ZEVM",
 		[]runner.ArgDefinition{
-			{Description: "amount in spl tokens", DefaultValue: "1000000"},
+			{Description: "amount in spl tokens", DefaultValue: "100000"},
 		},
 		TestSPLWithdraw,
 	),

x/crosschain/keeper/cctx_orchestrator_validate_outbound.go

@@ -198,6 +198,7 @@ func (k Keeper) processFailedOutboundOnExternalChain(
 		err = k.validateZRC20Withdrawal(
 			ctx,
 			cctx.GetCurrentOutboundParam().ReceiverChainId,
+			cctx.InboundParams.CoinType,
 			cctx.GetCurrentOutboundParam().Amount.BigInt(),
 			[]byte(cctx.GetCurrentOutboundParam().Receiver),
 		)

x/crosschain/keeper/evm_hooks.go

@@ -133,7 +133,7 @@ func (k Keeper) ProcessZEVMInboundV1(
 
 		// If Validation fails, we will not process the event and return and error. This condition means that the event was correct, and emitted from a registered ZRC20 contract
 		// But the information entered by the user is incorrect. In this case we can return an error and roll back the transaction
-		if err := k.ValidateZRC20WithdrawEvent(ctx, eventZRC20Withdrawal, coin.ForeignChainId); err != nil {
+		if err := k.ValidateZRC20WithdrawEvent(ctx, eventZRC20Withdrawal, coin.ForeignChainId, coin.CoinType); err != nil {
 			return err
 		}
 		// If the event is valid, we will process it and create a new CCTX
@@ -305,14 +305,25 @@ func (k Keeper) ProcessZetaSentEvent(
 
 // ValidateZRC20WithdrawEvent checks if the ZRC20Withdrawal event is valid
 // It verifies event information for BTC chains and returns an error if the event is invalid
-func (k Keeper) ValidateZRC20WithdrawEvent(ctx sdk.Context, event *zrc20.ZRC20Withdrawal, chainID int64) error {
+func (k Keeper) ValidateZRC20WithdrawEvent(
+	ctx sdk.Context,
+	event *zrc20.ZRC20Withdrawal,
+	chainID int64,
+	coinType coin.CoinType,
+) error {
 	// The event was parsed; that means the user has deposited tokens to the contract.
-	return k.validateZRC20Withdrawal(ctx, chainID, event.Value, event.To)
+	return k.validateZRC20Withdrawal(ctx, chainID, coinType, event.Value, event.To)
 }
 
 // validateZRC20Withdrawal validates the data of a ZRC20 Withdrawal event (version 1 or 2)
 // it checks if the withdrawal amount is valid and the destination address is supported depending on the chain
-func (k Keeper) validateZRC20Withdrawal(ctx sdk.Context, chainID int64, value *big.Int, to []byte) error {
+func (k Keeper) validateZRC20Withdrawal(
+	ctx sdk.Context,
+	chainID int64,
+	coinType coin.CoinType,
+	value *big.Int,
+	to []byte,
+) error {
 	additionalChains := k.GetAuthorityKeeper().GetAdditionalChainList(ctx)
 	if chains.IsBitcoinChain(chainID, additionalChains) {
 		if value.Cmp(big.NewInt(constant.BTCWithdrawalDustAmount)) < 0 {
@@ -331,7 +342,9 @@ func (k Keeper) validateZRC20Withdrawal(ctx sdk.Context, chainID int64, value *b
 			return errorsmod.Wrapf(types.ErrInvalidAddress, "unsupported address %s", string(to))
 		}
 	} else if chains.IsSolanaChain(chainID, additionalChains) {
-		if value.Cmp(big.NewInt(constant.SolanaWalletRentExempt)) < 0 {
+		// The rent exempt check is not needed for ZRC20 (SPL) tokens because withdrawing SPL token
+		// already needs a non-trivial amount of SOL for potential ATA creation so we can skip the check.
+		if coinType == coin.CoinType_Gas && value.Cmp(big.NewInt(constant.SolanaWalletRentExempt)) < 0 {
 			return errorsmod.Wrapf(
 				types.ErrInvalidWithdrawalAmount,
 				"withdraw amount %s is less than rent exempt %d",

x/crosschain/keeper/evm_hooks_test.go

@@ -15,6 +15,7 @@ import (
 
 	"github.com/zeta-chain/node/cmd/zetacored/config"
 	"github.com/zeta-chain/node/pkg/chains"
+	"github.com/zeta-chain/node/pkg/coin"
 	"github.com/zeta-chain/node/pkg/constant"
 	keepertest "github.com/zeta-chain/node/testutil/keeper"
 	"github.com/zeta-chain/node/testutil/sample"
@@ -154,14 +155,47 @@ func TestParseZRC20WithdrawalEvent(t *testing.T) {
 		}
 	})
 }
+
 func TestValidateZrc20WithdrawEvent(t *testing.T) {
-	t.Run("successfully validate a valid event", func(t *testing.T) {
+	t.Run("successfully validate a valid BTC withdrawal event", func(t *testing.T) {
 		k, ctx, _, _ := keepertest.CrosschainKeeper(t)
 		btcMainNetWithdrawalEvent, err := crosschainkeeper.ParseZRC20WithdrawalEvent(
 			*sample.ValidZRC20WithdrawToBTCReceipt(t).Logs[3],
 		)
 		require.NoError(t, err)
-		err = k.ValidateZRC20WithdrawEvent(ctx, btcMainNetWithdrawalEvent, chains.BitcoinMainnet.ChainId)
+		err = k.ValidateZRC20WithdrawEvent(
+			ctx,
+			btcMainNetWithdrawalEvent,
+			chains.BitcoinMainnet.ChainId,
+			coin.CoinType_Gas,
+		)
+		require.NoError(t, err)
+	})
+
+	t.Run("successfully validate a valid SOL withdrawal event", func(t *testing.T) {
+		k, ctx, _, _ := keepertest.CrosschainKeeper(t)
+
+		// 1000000 lamports is the minimum amount (rent exempt) that can be withdrawn
+		chainID := chains.SolanaMainnet.ChainId
+		to := []byte(sample.SolanaAddress(t))
+		value := big.NewInt(constant.SolanaWalletRentExempt)
+		solWithdrawalEvent := sample.ZRC20Withdrawal(to, value)
+
+		// 1000000 lamports can be withdrawn
+		err := k.ValidateZRC20WithdrawEvent(ctx, solWithdrawalEvent, chainID, coin.CoinType_Gas)
+		require.NoError(t, err)
+	})
+
+	t.Run("successfully validate a small amount of SPL withdrawal event", func(t *testing.T) {
+		k, ctx, _, _ := keepertest.CrosschainKeeper(t)
+
+		// set SPL token amount to 1
+		chainID := chains.SolanaMainnet.ChainId
+		to := []byte(sample.SolanaAddress(t))
+		solWithdrawalEvent := sample.ZRC20Withdrawal(to, big.NewInt(1))
+
+		// should withdraw successfully
+		err := k.ValidateZRC20WithdrawEvent(ctx, solWithdrawalEvent, chainID, coin.CoinType_ERC20)
 		require.NoError(t, err)
 	})
 
@@ -174,12 +208,22 @@ func TestValidateZrc20WithdrawEvent(t *testing.T) {
 
 		// 1000 satoshis is the minimum amount that can be withdrawn
 		btcMainNetWithdrawalEvent.Value = big.NewInt(constant.BTCWithdrawalDustAmount)
-		err = k.ValidateZRC20WithdrawEvent(ctx, btcMainNetWithdrawalEvent, chains.BitcoinMainnet.ChainId)
+		err = k.ValidateZRC20WithdrawEvent(
+			ctx,
+			btcMainNetWithdrawalEvent,
+			chains.BitcoinMainnet.ChainId,
+			coin.CoinType_Gas,
+		)
 		require.NoError(t, err)
 
 		// 999 satoshis cannot be withdrawn
 		btcMainNetWithdrawalEvent.Value = big.NewInt(constant.BTCWithdrawalDustAmount - 1)
-		err = k.ValidateZRC20WithdrawEvent(ctx, btcMainNetWithdrawalEvent, chains.BitcoinMainnet.ChainId)
+		err = k.ValidateZRC20WithdrawEvent(
+			ctx,
+			btcMainNetWithdrawalEvent,
+			chains.BitcoinMainnet.ChainId,
+			coin.CoinType_Gas,
+		)
 		require.ErrorContains(t, err, "less than dust amount")
 	})
 
@@ -189,7 +233,12 @@ func TestValidateZrc20WithdrawEvent(t *testing.T) {
 			*sample.ValidZRC20WithdrawToBTCReceipt(t).Logs[3],
 		)
 		require.NoError(t, err)
-		err = k.ValidateZRC20WithdrawEvent(ctx, btcMainNetWithdrawalEvent, chains.BitcoinTestnet.ChainId)
+		err = k.ValidateZRC20WithdrawEvent(
+			ctx,
+			btcMainNetWithdrawalEvent,
+			chains.BitcoinTestnet.ChainId,
+			coin.CoinType_Gas,
+		)
 		require.ErrorContains(t, err, "invalid address")
 	})
 
@@ -201,7 +250,12 @@ func TestValidateZrc20WithdrawEvent(t *testing.T) {
 		require.NoError(t, err)
 		btcMainNetWithdrawalEvent.To = []byte("04b2891ba8cb491828db3ebc8a780d43b169e7b3974114e6e50f9bab6ec" +
 			"63c2f20f6d31b2025377d05c2a704d3bd799d0d56f3a8543d79a01ab6084a1cb204f260")
-		err = k.ValidateZRC20WithdrawEvent(ctx, btcMainNetWithdrawalEvent, chains.BitcoinMainnet.ChainId)
+		err = k.ValidateZRC20WithdrawEvent(
+			ctx,
+			btcMainNetWithdrawalEvent,
+			chains.BitcoinMainnet.ChainId,
+			coin.CoinType_Gas,
+		)
 		require.ErrorContains(t, err, "unsupported address")
 	})
 
@@ -213,26 +267,21 @@ func TestValidateZrc20WithdrawEvent(t *testing.T) {
 		value := big.NewInt(constant.SolanaWalletRentExempt)
 		solWithdrawalEvent := sample.ZRC20Withdrawal(to, value)
 
-		err := k.ValidateZRC20WithdrawEvent(ctx, solWithdrawalEvent, chains.SolanaMainnet.ChainId)
+		err := k.ValidateZRC20WithdrawEvent(ctx, solWithdrawalEvent, chains.SolanaMainnet.ChainId, coin.CoinType_Gas)
 		require.ErrorContains(t, err, "invalid address")
 	})
 
-	t.Run("unable to validate a solana withdrawal event with an invalid amount", func(t *testing.T) {
+	t.Run("unable to validate a SOL withdrawal event with an invalid amount", func(t *testing.T) {
 		k, ctx, _, _ := keepertest.CrosschainKeeper(t)
 
 		// 1000000 lamports is the minimum amount (rent exempt) that can be withdrawn
 		chainID := chains.SolanaMainnet.ChainId
 		to := []byte(sample.SolanaAddress(t))
-		value := big.NewInt(constant.SolanaWalletRentExempt)
+		value := big.NewInt(constant.SolanaWalletRentExempt - 1)
 		solWithdrawalEvent := sample.ZRC20Withdrawal(to, value)
 
-		// 1000000 lamports can be withdrawn
-		err := k.ValidateZRC20WithdrawEvent(ctx, solWithdrawalEvent, chainID)
-		require.NoError(t, err)
-
 		// 999999 lamports cannot be withdrawn
-		solWithdrawalEvent.Value = big.NewInt(constant.SolanaWalletRentExempt - 1)
-		err = k.ValidateZRC20WithdrawEvent(ctx, solWithdrawalEvent, chainID)
+		err := k.ValidateZRC20WithdrawEvent(ctx, solWithdrawalEvent, chainID, coin.CoinType_Gas)
 		require.ErrorContains(t, err, "less than rent exempt")
 	})
 }

x/crosschain/keeper/v2_zevm_inbound.go

@@ -75,7 +75,7 @@ func (k Keeper) ProcessZEVMInboundV2(
 		}
 
 		// validate data of the withdrawal event
-		if err := k.validateZRC20Withdrawal(ctx, foreignCoin.ForeignChainId, value, receiver); err != nil {
+		if err := k.validateZRC20Withdrawal(ctx, foreignCoin.ForeignChainId, foreignCoin.CoinType, value, receiver); err != nil {
 			return err
 		}