Xcm trap assets ed

runtime/acala/src/lib.rs

@@ -44,7 +44,7 @@ use sp_runtime::{
 	transaction_validity::{TransactionSource, TransactionValidity},
 	ApplyExtrinsicResult, DispatchResult, FixedPointNumber, Perbill, Percent, Permill, Perquintill,
 };
-use sp_std::prelude::*;
+use sp_std::{marker::PhantomData, prelude::*};
 #[cfg(feature = "std")]
 use sp_version::NativeVersion;
 use sp_version::RuntimeVersion;
@@ -58,7 +58,8 @@ use module_relaychain::RelayChainCallBuilder;
 use module_support::{DispatchableTask, ForeignAssetIdMapping};
 use module_transaction_payment::{Multiplier, TargetedFeeAdjustment};
 use orml_traits::{
-	create_median_value_data_provider, parameter_type_with_key, DataFeeder, DataProviderExtended, MultiCurrency,
+	create_median_value_data_provider, parameter_type_with_key, DataFeeder, DataProviderExtended, GetByKey,
+	MultiCurrency,
 };
 use pallet_transaction_payment::RuntimeDispatchInfo;
 
@@ -95,6 +96,7 @@ pub use pallet_staking::StakerStatus;
 pub use pallet_timestamp::Call as TimestampCall;
 #[cfg(any(feature = "std", test))]
 pub use sp_runtime::BuildStorage;
+use xcm_executor::traits::DropAssets;
 
 pub use authority::AuthorityConfigImpl;
 pub use constants::{fee::*, time::*};
@@ -728,6 +730,17 @@ impl DataFeeder<CurrencyId, Price, AccountId> for AggregatedDataProvider {
 	}
 }
 
+pub struct ExistentialDepositsForDropAssets;
+impl ExistentialDepositsForDropAssets {
+	fn get(currency_id: &CurrencyId) -> Balance {
+		if currency_id == &GetNativeCurrencyId::get() {
+			NativeTokenExistentialDeposit::get()
+		} else {
+			<ExistentialDeposits as GetByKey<CurrencyId, Balance>>::get(currency_id)
+		}
+	}
+}
+
 parameter_type_with_key! {
 	pub ExistentialDeposits: |currency_id: CurrencyId| -> Balance {
 		match currency_id {
@@ -1429,6 +1442,40 @@ impl TakeRevenue for ToTreasury {
 	}
 }
 
+pub struct AcalaDropAssets<X, T>(PhantomData<(X, T)>);
+impl<X, T> DropAssets for AcalaDropAssets<X, T>
+where
+	X: DropAssets,
+	T: TakeRevenue,
+{
+	fn drop_assets(origin: &MultiLocation, assets: Assets) -> Weight {
+		let multi_assets: Vec<MultiAsset> = assets.into();
+		let mut asset_traps: Vec<MultiAsset> = vec![];
+		for asset in multi_assets {
+			if let MultiAsset {
+				id: Concrete(location),
+				fun: Fungible(amount),
+			} = asset.clone()
+			{
+				let currency_id = CurrencyIdConvert::convert(location);
+				// burn asset(do nothing here) if convert result is None
+				if let Some(currency_id) = currency_id {
+					let ed = ExistentialDepositsForDropAssets::get(&currency_id);
+					if amount < ed {
+						T::take_revenue(asset);
+					} else {
+						asset_traps.push(asset);
+					}
+				}
+			}
+		}
+		if !asset_traps.is_empty() {
+			X::drop_assets(origin, asset_traps.into());
+		}
+		0
+	}
+}
+
 pub type Trader = (
 	FixedRateOfFungible<DotPerSecond, ToTreasury>,
 	FixedRateOfFungible<AusdPerSecond, ToTreasury>,

runtime/integration-tests/src/relaychain/kusama_cross_chain_transfer.rs

@@ -23,7 +23,7 @@ use crate::setup::*;
 
 use frame_support::assert_ok;
 
-use karura_runtime::AssetRegistry;
+use karura_runtime::{AssetRegistry, KaruraTreasuryAccount};
 use module_asset_registry::AssetMetadata;
 use orml_traits::MultiCurrency;
 use xcm_emulator::TestExt;
@@ -475,3 +475,178 @@ fn test_asset_registry_module() {
 		);
 	});
 }
+
+#[test]
+fn trap_assets_larger_than_ed_works() {
+	TestNet::reset();
+
+	let mut kar_treasury_amount = 0;
+	let (ksm_asset_amount, kar_asset_amount) = (dollar(KSM), dollar(KAR));
+	let trader_weight_to_treasury: u128 = 96_000_000;
+
+	Karura::execute_with(|| {
+		assert_ok!(Tokens::deposit(KSM, &AccountId::from(DEFAULT), 100 * dollar(KSM)));
+		let _ = pallet_balances::Pallet::<Runtime>::deposit_creating(&AccountId::from(DEFAULT), 100 * dollar(KAR));
+
+		kar_treasury_amount = Currencies::free_balance(KAR, &KaruraTreasuryAccount::get());
+	});
+
+	let assets: MultiAsset = (Parent, ksm_asset_amount).into();
+	KusamaNet::execute_with(|| {
+		let xcm = vec![
+			WithdrawAsset(assets.clone().into()),
+			BuyExecution {
+				fees: assets,
+				weight_limit: Limited(dollar(KSM) as u64),
+			},
+			WithdrawAsset(
+				(
+					(Parent, X2(Parachain(2000), GeneralKey(KAR.encode()))),
+					kar_asset_amount,
+				)
+					.into(),
+			),
+		];
+		assert_ok!(pallet_xcm::Pallet::<kusama_runtime::Runtime>::send_xcm(
+			Here,
+			Parachain(2000).into(),
+			Xcm(xcm),
+		));
+	});
+	Karura::execute_with(|| {
+		assert!(System::events()
+			.iter()
+			.any(|r| matches!(r.event, Event::PolkadotXcm(pallet_xcm::Event::AssetsTrapped(_, _, _)))));
+
+		assert_eq!(
+			trader_weight_to_treasury,
+			Currencies::free_balance(KSM, &KaruraTreasuryAccount::get())
+		);
+		assert_eq!(
+			kar_treasury_amount,
+			Currencies::free_balance(KAR, &KaruraTreasuryAccount::get())
+		);
+	});
+}
+
+#[test]
+fn trap_assets_lower_than_ed_works() {
+	TestNet::reset();
+
+	let mut kar_treasury_amount = 0;
+	let (ksm_asset_amount, kar_asset_amount) = (cent(KSM) / 100, cent(KAR));
+
+	Karura::execute_with(|| {
+		assert_ok!(Tokens::deposit(KSM, &AccountId::from(DEFAULT), dollar(KSM)));
+		let _ = pallet_balances::Pallet::<Runtime>::deposit_creating(&AccountId::from(DEFAULT), dollar(KAR));
+		kar_treasury_amount = Currencies::free_balance(KAR, &KaruraTreasuryAccount::get());
+	});
+
+	let assets: MultiAsset = (Parent, ksm_asset_amount).into();
+	KusamaNet::execute_with(|| {
+		let xcm = vec![
+			WithdrawAsset(assets.clone().into()),
+			BuyExecution {
+				fees: assets,
+				weight_limit: Limited(dollar(KSM) as u64),
+			},
+			WithdrawAsset(
+				(
+					(Parent, X2(Parachain(2000), GeneralKey(KAR.encode()))),
+					kar_asset_amount,
+				)
+					.into(),
+			),
+			// two asset left in holding register, they both lower than ED, so goes to treasury.
+		];
+		assert_ok!(pallet_xcm::Pallet::<kusama_runtime::Runtime>::send_xcm(
+			Here,
+			Parachain(2000).into(),
+			Xcm(xcm),
+		));
+	});
+
+	Karura::execute_with(|| {
+		assert_eq!(
+			System::events()
+				.iter()
+				.find(|r| matches!(r.event, Event::PolkadotXcm(pallet_xcm::Event::AssetsTrapped(_, _, _)))),
+			None
+		);
+
+		assert_eq!(
+			ksm_asset_amount,
+			Currencies::free_balance(KSM, &KaruraTreasuryAccount::get())
+		);
+		assert_eq!(
+			kar_asset_amount,
+			Currencies::free_balance(KAR, &KaruraTreasuryAccount::get()) - kar_treasury_amount
+		);
+	});
+}
+
+#[test]
+fn sibling_trap_assets_works() {
+	TestNet::reset();
+
+	let mut kar_treasury_amount = 0;
+	let (bnc_asset_amount, kar_asset_amount) = (cent(BNC) / 10, cent(KAR));
+
+	fn sibling_account() -> AccountId {
+		use sp_runtime::traits::AccountIdConversion;
+		polkadot_parachain::primitives::Sibling::from(2001).into_account()
+	}
+
+	Karura::execute_with(|| {
+		assert_ok!(Tokens::deposit(BNC, &sibling_account(), dollar(BNC)));
+		let _ = pallet_balances::Pallet::<Runtime>::deposit_creating(&sibling_account(), dollar(KAR));
+		kar_treasury_amount = Currencies::free_balance(KAR, &KaruraTreasuryAccount::get());
+	});
+
+	Sibling::execute_with(|| {
+		let assets: MultiAsset = (
+			(Parent, X2(Parachain(2000), GeneralKey(KAR.encode()))),
+			kar_asset_amount,
+		)
+			.into();
+		let xcm = vec![
+			WithdrawAsset(assets.clone().into()),
+			BuyExecution {
+				fees: assets,
+				weight_limit: Unlimited,
+			},
+			WithdrawAsset(
+				(
+					(
+						Parent,
+						X2(Parachain(2001), GeneralKey(parachains::bifrost::BNC_KEY.to_vec())),
+					),
+					bnc_asset_amount,
+				)
+					.into(),
+			),
+		];
+		assert_ok!(pallet_xcm::Pallet::<Runtime>::send_xcm(
+			Here,
+			(Parent, Parachain(2000)),
+			Xcm(xcm),
+		));
+	});
+
+	Karura::execute_with(|| {
+		assert_eq!(
+			System::events()
+				.iter()
+				.find(|r| matches!(r.event, Event::PolkadotXcm(pallet_xcm::Event::AssetsTrapped(_, _, _)))),
+			None
+		);
+		assert_eq!(
+			Currencies::free_balance(KAR, &KaruraTreasuryAccount::get()) - kar_treasury_amount,
+			kar_asset_amount
+		);
+		assert_eq!(
+			Currencies::free_balance(BNC, &KaruraTreasuryAccount::get()),
+			bnc_asset_amount
+		);
+	});
+}

runtime/integration-tests/src/setup.rs

@@ -150,6 +150,7 @@ const ORACLE3: [u8; 32] = [2u8; 32];
 const ORACLE4: [u8; 32] = [3u8; 32];
 const ORACLE5: [u8; 32] = [4u8; 32];
 
+pub const DEFAULT: [u8; 32] = [0u8; 32];
 pub const ALICE: [u8; 32] = [4u8; 32];
 pub const BOB: [u8; 32] = [5u8; 32];
 pub const CHARLIE: [u8; 32] = [6u8; 32];

runtime/karura/src/lib.rs

@@ -44,7 +44,7 @@ use sp_runtime::{
 	transaction_validity::{TransactionSource, TransactionValidity},
 	ApplyExtrinsicResult, DispatchResult, FixedPointNumber, Perbill, Percent, Permill, Perquintill,
 };
-use sp_std::prelude::*;
+use sp_std::{marker::PhantomData, prelude::*};
 #[cfg(feature = "std")]
 use sp_version::NativeVersion;
 use sp_version::RuntimeVersion;
@@ -59,7 +59,8 @@ use module_support::{DispatchableTask, ForeignAssetIdMapping};
 use module_transaction_payment::{Multiplier, TargetedFeeAdjustment};
 
 use orml_traits::{
-	create_median_value_data_provider, parameter_type_with_key, DataFeeder, DataProviderExtended, MultiCurrency,
+	create_median_value_data_provider, parameter_type_with_key, DataFeeder, DataProviderExtended, GetByKey,
+	MultiCurrency,
 };
 use pallet_transaction_payment::RuntimeDispatchInfo;
 
@@ -76,7 +77,10 @@ pub use xcm_builder::{
 	SiblingParachainConvertsVia, SignedAccountId32AsNative, SignedToAccountId32, SovereignSignedViaLocation,
 	TakeRevenue, TakeWeightCredit,
 };
-pub use xcm_executor::{traits::WeightTrader, Assets, Config, XcmExecutor};
+pub use xcm_executor::{
+	traits::{DropAssets, WeightTrader},
+	Assets, Config, XcmExecutor,
+};
 
 /// Weights for pallets used in the runtime.
 mod weights;
@@ -738,6 +742,17 @@ impl DataFeeder<CurrencyId, Price, AccountId> for AggregatedDataProvider {
 	}
 }
 
+pub struct ExistentialDepositsForDropAssets;
+impl ExistentialDepositsForDropAssets {
+	fn get(currency_id: &CurrencyId) -> Balance {
+		if currency_id == &GetNativeCurrencyId::get() {
+			NativeTokenExistentialDeposit::get()
+		} else {
+			<ExistentialDeposits as GetByKey<CurrencyId, Balance>>::get(currency_id)
+		}
+	}
+}
+
 parameter_type_with_key! {
 	pub ExistentialDeposits: |currency_id: CurrencyId| -> Balance {
 		match currency_id {
@@ -1468,6 +1483,40 @@ impl TakeRevenue for ToTreasury {
 	}
 }
 
+pub struct AcalaDropAssets<X, T>(PhantomData<(X, T)>);
+impl<X, T> DropAssets for AcalaDropAssets<X, T>
+where
+	X: DropAssets,
+	T: TakeRevenue,
+{
+	fn drop_assets(origin: &MultiLocation, assets: Assets) -> Weight {
+		let multi_assets: Vec<MultiAsset> = assets.into();
+		let mut asset_traps: Vec<MultiAsset> = vec![];
+		for asset in multi_assets {
+			if let MultiAsset {
+				id: Concrete(location),
+				fun: Fungible(amount),
+			} = asset.clone()
+			{
+				let currency_id = CurrencyIdConvert::convert(location);
+				// burn asset(do nothing here) if convert result is None
+				if let Some(currency_id) = currency_id {
+					let ed = ExistentialDepositsForDropAssets::get(&currency_id);
+					if amount < ed {
+						T::take_revenue(asset);
+					} else {
+						asset_traps.push(asset);
+					}
+				}
+			}
+		}
+		if !asset_traps.is_empty() {
+			X::drop_assets(origin, asset_traps.into());
+		}
+		0
+	}
+}
+
 parameter_types! {
 	pub BncPerSecond: (AssetId, u128) = (
 		MultiLocation::new(
@@ -1513,7 +1562,7 @@ impl xcm_executor::Config for XcmConfig {
 	type Weigher = FixedWeightBounds<UnitWeightCost, Call, MaxInstructions>;
 	type Trader = Trader;
 	type ResponseHandler = PolkadotXcm;
-	type AssetTrap = PolkadotXcm;
+	type AssetTrap = AcalaDropAssets<PolkadotXcm, ToTreasury>;
 	type AssetClaims = PolkadotXcm;
 	type SubscriptionService = PolkadotXcm;
 }