Use low level execute directly

bridges/snowbridge/primitives/router/src/outbound/mod.rs

@@ -148,11 +148,9 @@ enum XcmConverterError {
 	DepositAssetExpected,
 	NoReserveAssets,
 	FilterDoesNotConsumeAllAssets,
-	TooManyAssets,
 	ZeroAssetTransfer,
 	BeneficiaryResolutionFailed,
 	AssetResolutionFailed,
-	InvalidFeeAsset,
 	SetTopicExpected,
 }
 
@@ -233,18 +231,8 @@ impl<'a, Call> XcmConverter<'a, Call> {
 			return Err(FilterDoesNotConsumeAllAssets)
 		}
 
-		// We only support a single asset at a time.
-		ensure!(reserve_assets.len() == 1, TooManyAssets);
 		let reserve_asset = reserve_assets.get(0).ok_or(AssetResolutionFailed)?;
 
-		// If there was a fee specified verify it.
-		if let Some(fee_asset) = fee_asset {
-			// The fee asset must be the same as the reserve asset.
-			if fee_asset.id != reserve_asset.id || fee_asset.fun > reserve_asset.fun {
-				return Err(InvalidFeeAsset)
-			}
-		}
-
 		let (token, amount) = match reserve_asset {
 			Asset { id: AssetId(inner_location), fun: Fungible(amount) } =>
 				match inner_location.unpack() {

cumulus/parachains/integration-tests/emulated/tests/bridges/bridge-hub-rococo/src/tests/snowbridge.rs

@@ -395,6 +395,7 @@ fn send_weth_asset_from_asset_hub_to_ethereum() {
 	AssetHubRococo::fund_accounts(vec![(AssetHubRococoReceiver::get(), INITIAL_FUND)]);
 
 	const WETH_AMOUNT: u128 = 1_000_000_000;
+	const FEE_AMOUNT: u128 = 1_000;
 
 	BridgeHubRococo::execute_with(|| {
 		type RuntimeEvent = <BridgeHubRococo as Chain>::RuntimeEvent;
@@ -433,7 +434,8 @@ fn send_weth_asset_from_asset_hub_to_ethereum() {
 				RuntimeEvent::ForeignAssets(pallet_assets::Event::Issued { .. }) => {},
 			]
 		);
-		let assets = vec![Asset {
+		let fee_asset = Asset { id: AssetId(Location::parent()), fun: Fungible(FEE_AMOUNT) };
+		let weth_asset = Asset {
 			id: AssetId(Location::new(
 				2,
 				[
@@ -442,30 +444,44 @@ fn send_weth_asset_from_asset_hub_to_ethereum() {
 				],
 			)),
 			fun: Fungible(WETH_AMOUNT),
-		}];
-		let multi_assets = VersionedAssets::V4(Assets::from(assets));
+		};
+		let assets = vec![fee_asset.clone(), weth_asset.clone()];
 
-		let destination = VersionedLocation::V4(Location::new(
-			2,
-			[GlobalConsensus(Ethereum { chain_id: CHAIN_ID })],
-		));
+		let destination = Location::new(2, [GlobalConsensus(Ethereum { chain_id: CHAIN_ID })]);
 
-		let beneficiary = VersionedLocation::V4(Location::new(
+		let beneficiary = Location::new(
 			0,
 			[AccountKey20 { network: None, key: ETHEREUM_DESTINATION_ADDRESS.into() }],
-		));
+		);
+
+		let mut reanchored_fee = fee_asset.clone();
+
+		let universal_location: InteriorLocation =
+			Junctions::from([GlobalConsensus(NetworkId::Rococo), Parachain(1000)]);
 
+		reanchored_fee = reanchored_fee.reanchored(&destination, &universal_location).unwrap();
+
+		let xcm_on_bh = Xcm(vec![
+			BuyExecution { fees: reanchored_fee.clone(), weight_limit: Unlimited },
+			DepositAsset { assets: Wild(AllCounted(2)), beneficiary },
+		]);
+
+		let xcms = VersionedXcm::from(Xcm(vec![
+			WithdrawAsset(assets.clone().into()),
+			SetFeesMode { jit_withdraw: true },
+			InitiateReserveWithdraw {
+				assets: Wild(AllCounted(2)),
+				reserve: destination,
+				xcm: xcm_on_bh,
+			},
+		]));
 		let free_balance_before = <AssetHubRococo as AssetHubRococoPallet>::Balances::free_balance(
 			AssetHubRococoReceiver::get(),
 		);
-		// Send the Weth back to Ethereum
-		<AssetHubRococo as AssetHubRococoPallet>::PolkadotXcm::limited_reserve_transfer_assets(
+		<AssetHubRococo as AssetHubRococoPallet>::PolkadotXcm::execute(
 			RuntimeOrigin::signed(AssetHubRococoReceiver::get()),
-			Box::new(destination),
-			Box::new(beneficiary),
-			Box::new(multi_assets),
-			0,
-			Unlimited,
+			bx!(xcms),
+			Weight::from(8_000_000_000),
 		)
 		.unwrap();
 		let free_balance_after = <AssetHubRococo as AssetHubRococoPallet>::Balances::free_balance(