Fix xcm execution fee destinations

integration-tests/src/tests/mod.rs

@@ -22,3 +22,4 @@ mod governance;
 mod oracle;
 mod reserve_backed_transfers;
 mod vest;
+mod xcm_config;

integration-tests/src/tests/xcm_config.rs

@@ -0,0 +1,68 @@
+use crate::{PolimecAccountId, PolimecCall, PolimecForeignAssets, PolimecNet, PolimecRuntime};
+use parity_scale_codec::Encode;
+use polimec_runtime::{xcm_config::SupportedAssets, ForeignAssets, TreasuryAccount};
+use sp_runtime::traits::MaybeEquivalence;
+use xcm::prelude::*;
+use xcm_emulator::TestExt;
+
+pub fn fake_message_hash<T>(message: &Xcm<T>) -> XcmHash {
+	message.using_encoded(sp_io::hashing::blake2_256)
+}
+#[test]
+fn execution_fees_go_to_treasury() {
+	let relay = MultiLocation::parent();
+	let asset_hub = MultiLocation::new(1, X1(Parachain(1000)));
+	let dot_amount = MultiAsset { id: Concrete(relay), fun: Fungible(100_0_000_000_000) };
+	let usdt_amount = MultiAsset {
+		id: Concrete(MultiLocation {
+			parents: 1,
+			interior: X3(Parachain(1000), PalletInstance(50), GeneralIndex(1984)),
+		}),
+		fun: Fungible(100_000_000),
+	};
+	let usdc_amount = MultiAsset {
+		id: Concrete(MultiLocation {
+			parents: 1,
+			interior: X3(Parachain(1000), PalletInstance(50), GeneralIndex(1337)),
+		}),
+		fun: Fungible(100_000_000),
+	};
+
+	let plmc_amount = MultiAsset { id: Concrete(relay), fun: Fungible(100_0_000_000_000) };
+	let beneficiary: PolimecAccountId = [0u8; 32].into();
+
+	let assert_fee_goes_to_treasury = |multi_asset: MultiAsset| {
+		let asset_multilocation =
+			if let Concrete(asset_multilocation) = multi_asset.id { asset_multilocation } else { unreachable!() };
+		let asset_id = SupportedAssets::convert(&asset_multilocation).unwrap();
+		let asset_amount = if let Fungible(amount) = multi_asset.fun { amount } else { unreachable!() };
+
+		let xcm = Xcm::<PolimecCall>(vec![
+			ReserveAssetDeposited(vec![multi_asset.clone()].into()),
+			ClearOrigin,
+			BuyExecution { fees: multi_asset, weight_limit: Unlimited },
+			DepositAsset {
+				assets: WildMultiAsset::All.into(),
+				beneficiary: MultiLocation::new(0, X1(AccountId32 { network: None, id: beneficiary.clone().into() })),
+			},
+		])
+		.into();
+		PolimecNet::execute_with(|| {
+			let outcome = <PolimecRuntime as pallet_xcm::Config>::XcmExecutor::execute_xcm(
+				asset_hub,
+				xcm.clone(),
+				fake_message_hash(&xcm),
+				Weight::MAX,
+			);
+			assert!(outcome.ensure_complete().is_ok());
+
+			let treasury_balance = PolimecForeignAssets::balance(asset_id, TreasuryAccount::get());
+			let beneficiary_balance = PolimecForeignAssets::balance(asset_id, beneficiary.clone());
+			assert_eq!(asset_amount, treasury_balance + beneficiary_balance);
+		});
+	};
+
+	assert_fee_goes_to_treasury(dot_amount);
+	assert_fee_goes_to_treasury(usdt_amount);
+	assert_fee_goes_to_treasury(usdc_amount);
+}

runtimes/polimec/src/lib.rs

@@ -27,14 +27,16 @@ use frame_support::{
 	traits::{
 		fungible::{Credit, HoldConsideration, Inspect},
 		tokens::{self, PayFromAccount, UnityAssetBalanceConversion},
-		AsEnsureOriginWithArg, ConstU32, Contains, EitherOfDiverse, InstanceFilter, LinearStoragePrice, PrivilegeCmp,
-		TransformOrigin,
+		AsEnsureOriginWithArg, ConstU32, Contains, Currency, EitherOfDiverse, InstanceFilter, LinearStoragePrice,
+		PrivilegeCmp, TransformOrigin,
 	},
 	weights::{ConstantMultiplier, Weight},
 };
 use frame_system::{EnsureRoot, EnsureRootWithSuccess, EnsureSigned, EnsureSignedBy};
+use pallet_balances::NegativeImbalance;
 use pallet_democracy::GetElectorate;
 use pallet_funding::DaysToBlocks;
+use pallet_treasury::NegativeImbalanceOf;
 
 use parachains_common::{
 	message_queue::{NarrowOriginToSibling, ParaIdToSibling},
@@ -551,6 +553,12 @@ impl tokens::imbalance::OnUnbalanced<CreditOf<Runtime>> for ToTreasury {
 		let _ = <Balances as tokens::fungible::Balanced<AccountId>>::resolve(&treasury_account, amount);
 	}
 }
+impl tokens::imbalance::OnUnbalanced<NegativeImbalance<Runtime>> for ToTreasury {
+	fn on_nonzero_unbalanced(amount: NegativeImbalance<Runtime>) {
+		let treasury_account = Treasury::account_id();
+		<Balances as Currency<AccountId>>::resolve_creating(&treasury_account, amount);
+	}
+}
 
 parameter_types! {
 	pub TreasuryAccount: AccountId = Treasury::account_id();

runtimes/polimec/src/xcm_config.rs

@@ -16,15 +16,16 @@
 
 use super::{
 	AccountId, AllPalletsWithSystem, AssetId as AssetIdPalletAssets, Balance, Balances, EnsureRoot, ForeignAssets,
-	ParachainInfo, ParachainSystem, PolkadotXcm, Runtime, RuntimeCall, RuntimeEvent, RuntimeOrigin, Vec, WeightToFee,
-	XcmpQueue,
+	ParachainInfo, ParachainSystem, PolkadotXcm, Runtime, RuntimeCall, RuntimeEvent, RuntimeOrigin, ToTreasury,
+	TreasuryAccount, Vec, WeightToFee, XcmpQueue,
 };
-use core::marker::PhantomData;
+use core::{iter::Take, marker::PhantomData};
 use frame_support::{
 	ensure, match_types, parameter_types,
 	traits::{ConstU32, Contains, ContainsPair, Everything, Nothing, ProcessMessageError},
 	weights::Weight,
 };
+use pallet_balances::NegativeImbalance;
 use pallet_xcm::XcmPassthrough;
 use polimec_xcm_executor::{
 	polimec_traits::{JustTry, Properties, ShouldExecute},
@@ -261,7 +262,8 @@ pub type Reserves = AssetHubAssetsAsReserve;
 /// ForeignAssetsAdapter is a FungiblesAdapter that allows for transacting foreign assets.
 /// Currently we only support DOT, USDT and USDC.
 pub type AssetTransactors = (FungibleTransactor, ForeignAssetsAdapter);
-
+pub type TakeRevenueToTreasury =
+	cumulus_primitives_utility::XcmFeesTo32ByteAccount<AssetTransactors, AccountId, TreasuryAccount>;
 pub struct XcmConfig;
 impl polimec_xcm_executor::Config for XcmConfig {
 	type Aliasers = ();
@@ -290,10 +292,10 @@ impl polimec_xcm_executor::Config for XcmConfig {
 	type SubscriptionService = PolkadotXcm;
 	type Trader = (
 		// TODO: weight to fee has to be carefully considered. For now use default
-		UsingComponents<WeightToFee, HereLocation, AccountId, Balances, ToAuthor<Runtime>>,
-		FixedRateOfFungible<UsdtTraderParams, ()>,
-		FixedRateOfFungible<DotTraderParams, ()>,
-		FixedRateOfFungible<UsdcTraderParams, ()>,
+		UsingComponents<WeightToFee, HereLocation, AccountId, Balances, ToTreasury>,
+		FixedRateOfFungible<UsdtTraderParams, TakeRevenueToTreasury>,
+		FixedRateOfFungible<DotTraderParams, TakeRevenueToTreasury>,
+		FixedRateOfFungible<UsdcTraderParams, TakeRevenueToTreasury>,
 	);
 	type UniversalAliases = Nothing;
 	type UniversalLocation = UniversalLocation;