Pallet XCM - transfer_assets pre-ahm patch

cumulus/parachains/integration-tests/emulated/tests/assets/asset-hub-westend/src/tests/mod.rs

@@ -26,6 +26,7 @@ mod set_xcm_versions;
 mod swap;
 mod teleport;
 mod transact;
+mod transfer_assets_validation;
 mod treasury;
 mod xcm_fee_estimation;
 

cumulus/parachains/integration-tests/emulated/tests/assets/asset-hub-westend/src/tests/teleport.rs

@@ -156,23 +156,57 @@ fn relay_to_system_para_limited_teleport_assets(t: RelayToSystemParaTest) -> Dis
 }
 
 fn para_to_system_para_transfer_assets(t: ParaToSystemParaTest) -> DispatchResult {
-	<PenpalA as PenpalAPallet>::PolkadotXcm::transfer_assets(
+	type Runtime = <PenpalA as Chain>::Runtime;
+	let remote_fee_id: AssetId = t
+		.args
+		.assets
+		.clone()
+		.into_inner()
+		.get(t.args.fee_asset_item as usize)
+		.ok_or(pallet_xcm::Error::<Runtime>::Empty)?
+		.clone()
+		.id;
+
+	<PenpalA as PenpalAPallet>::PolkadotXcm::transfer_assets_using_type_and_then(
 		t.signed_origin,
 		bx!(t.args.dest.into()),
-		bx!(t.args.beneficiary.into()),
 		bx!(t.args.assets.into()),
-		t.args.fee_asset_item,
+		bx!(TransferType::Teleport),
+		bx!(remote_fee_id.into()),
+		bx!(TransferType::DestinationReserve),
+		bx!(VersionedXcm::from(
+			Xcm::<()>::builder_unsafe()
+				.deposit_asset(AllCounted(2), t.args.beneficiary)
+				.build()
+		)),
 		t.args.weight_limit,
 	)
 }
 
 fn system_para_to_para_transfer_assets(t: SystemParaToParaTest) -> DispatchResult {
-	<AssetHubWestend as AssetHubWestendPallet>::PolkadotXcm::transfer_assets(
+	type Runtime = <AssetHubWestend as Chain>::Runtime;
+	let remote_fee_id: AssetId = t
+		.args
+		.assets
+		.clone()
+		.into_inner()
+		.get(t.args.fee_asset_item as usize)
+		.ok_or(pallet_xcm::Error::<Runtime>::Empty)?
+		.clone()
+		.id;
+
+	<AssetHubWestend as AssetHubWestendPallet>::PolkadotXcm::transfer_assets_using_type_and_then(
 		t.signed_origin,
 		bx!(t.args.dest.into()),
-		bx!(t.args.beneficiary.into()),
 		bx!(t.args.assets.into()),
-		t.args.fee_asset_item,
+		bx!(TransferType::Teleport),
+		bx!(remote_fee_id.into()),
+		bx!(TransferType::LocalReserve),
+		bx!(VersionedXcm::from(
+			Xcm::<()>::builder_unsafe()
+				.deposit_asset(AllCounted(2), t.args.beneficiary)
+				.build()
+		)),
 		t.args.weight_limit,
 	)
 }

cumulus/parachains/integration-tests/emulated/tests/assets/asset-hub-westend/src/tests/transfer_assets_validation.rs

@@ -0,0 +1,264 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Tests for the validation of `pallet_xcm::Pallet::<T>::transfer_assets`.
+//! See the `pallet_xcm::transfer_assets_validation` module for more information.
+
+use crate::imports::*;
+use frame_support::{assert_err, assert_ok};
+use sp_runtime::DispatchError;
+
+// ==================================================================================
+// ============================== PenpalA <-> Westend ===============================
+// ==================================================================================
+
+/// Test that `transfer_assets` fails when doing reserve transfer of WND from PenpalA to Westend.
+/// This fails because PenpalA's IsReserve config considers Westend as the reserve for WND,
+/// so transfer_assets automatically chooses reserve transfer, which we block.
+#[test]
+fn transfer_assets_wnd_reserve_transfer_para_to_relay_fails() {
+	let destination = PenpalA::parent_location();
+	let beneficiary: Location =
+		AccountId32Junction { network: None, id: WestendReceiver::get().into() }.into();
+	let amount_to_send: Balance = WESTEND_ED * 1000;
+	let assets: Assets = (Parent, amount_to_send).into();
+
+	// Mint WND on PenpalA for testing.
+	PenpalA::mint_foreign_asset(
+		<PenpalA as Chain>::RuntimeOrigin::signed(PenpalAssetOwner::get()),
+		RelayLocation::get(),
+		PenpalASender::get(),
+		amount_to_send * 2,
+	);
+
+	// Fund PenpalA's sovereign account on Westend with the reserve WND.
+	let penpal_location_as_seen_by_relay = Westend::child_location_of(PenpalA::para_id());
+	let sov_penpal_on_relay = Westend::sovereign_account_id_of(penpal_location_as_seen_by_relay);
+	Westend::fund_accounts(vec![(sov_penpal_on_relay.into(), amount_to_send * 2)]);
+
+	PenpalA::execute_with(|| {
+		let result = <PenpalA as PenpalAPallet>::PolkadotXcm::transfer_assets(
+			<PenpalA as Chain>::RuntimeOrigin::signed(PenpalASender::get()),
+			bx!(destination.into()),
+			bx!(beneficiary.into()),
+			bx!(assets.into()),
+			0,
+			WeightLimit::Unlimited,
+		);
+
+		// This should fail because WND reserve transfer is blocked.
+		assert_err!(
+			result,
+			DispatchError::Module(sp_runtime::ModuleError {
+				index: 31,
+				error: [21, 0, 0, 0], // InvalidAssetUnknownReserve.
+				message: Some("InvalidAssetUnknownReserve")
+			})
+		);
+	});
+}
+
+/// Test that `transfer_assets` fails when doing reserve transfer of WND from Westend to PenpalA
+/// This fails because Westend's configuration would make this a reserve transfer, which we block.
+#[test]
+fn transfer_assets_wnd_reserve_transfer_relay_to_para_fails() {
+	let destination = Westend::child_location_of(PenpalA::para_id());
+	let beneficiary: Location =
+		AccountId32Junction { network: None, id: PenpalAReceiver::get().into() }.into();
+	let amount_to_send: Balance = WESTEND_ED * 1000;
+	let assets: Assets = (Here, amount_to_send).into();
+
+	Westend::execute_with(|| {
+		let result = <Westend as WestendPallet>::XcmPallet::transfer_assets(
+			<Westend as Chain>::RuntimeOrigin::signed(WestendSender::get()),
+			bx!(destination.into()),
+			bx!(beneficiary.into()),
+			bx!(assets.into()),
+			0,
+			WeightLimit::Unlimited,
+		);
+
+		// This should fail because WND reserve transfer is blocked.
+		assert_err!(
+			result,
+			DispatchError::Module(sp_runtime::ModuleError {
+				index: 99,
+				error: [21, 0, 0, 0], // InvalidAssetUnknownReserve.
+				message: Some("InvalidAssetUnknownReserve")
+			})
+		);
+	});
+}
+
+// ==================================================================================
+// ============================== PenpalA <-> PenpalB ===============================
+// ==================================================================================
+
+/// Test that `transfer_assets` fails when doing reserve transfer of WND from PenpalA to PenpalB
+#[test]
+fn transfer_assets_wnd_reserve_transfer_para_to_para_fails() {
+	let destination = PenpalA::sibling_location_of(PenpalB::para_id());
+	let beneficiary: Location =
+		AccountId32Junction { network: None, id: PenpalBReceiver::get().into() }.into();
+	let amount_to_send: Balance = WESTEND_ED * 1000;
+	let assets: Assets = (Parent, amount_to_send).into();
+
+	// Mint WND on PenpalA for testing
+	PenpalA::mint_foreign_asset(
+		<PenpalA as Chain>::RuntimeOrigin::signed(PenpalAssetOwner::get()),
+		RelayLocation::get(),
+		PenpalASender::get(),
+		amount_to_send * 2,
+	);
+
+	PenpalA::execute_with(|| {
+		let result = <PenpalA as PenpalAPallet>::PolkadotXcm::transfer_assets(
+			<PenpalA as Chain>::RuntimeOrigin::signed(PenpalASender::get()),
+			bx!(destination.into()),
+			bx!(beneficiary.into()),
+			bx!(assets.into()),
+			0,
+			WeightLimit::Unlimited,
+		);
+
+		// This should fail because WND reserve transfer is blocked
+		assert_err!(
+			result,
+			DispatchError::Module(sp_runtime::ModuleError {
+				index: 31,
+				error: [21, 0, 0, 0], // InvalidAssetUnknownReserve
+				message: Some("InvalidAssetUnknownReserve")
+			})
+		);
+	});
+}
+
+// ==================================================================================
+// ============================== Mixed Assets and Fees =============================
+// ==================================================================================
+
+/// Test that `transfer_assets` fails when WND is used as fee asset in reserve transfer
+#[test]
+fn transfer_assets_wnd_as_fee_in_reserve_transfer_fails() {
+	let destination = PenpalA::sibling_location_of(PenpalB::para_id());
+	let beneficiary: Location =
+		AccountId32Junction { network: None, id: PenpalBReceiver::get().into() }.into();
+	let asset_amount: Balance = 1_000_000_000_000; // A million USDT.
+	let fee_amount: Balance = WESTEND_ED * 100;
+
+	// Create a foreign asset location (representing another asset).
+	let foreign_asset_location = Location::new(
+		1,
+		[
+			Parachain(AssetHubWestend::para_id().into()),
+			PalletInstance(ASSETS_PALLET_ID),
+			GeneralIndex(USDT_ID.into()), // USDT.
+		],
+	);
+
+	// Mint both assets on PenpalA for testing.
+	PenpalA::mint_foreign_asset(
+		<PenpalA as Chain>::RuntimeOrigin::signed(PenpalAssetOwner::get()),
+		foreign_asset_location.clone(),
+		PenpalASender::get(),
+		asset_amount * 2,
+	);
+	PenpalA::mint_foreign_asset(
+		<PenpalA as Chain>::RuntimeOrigin::signed(PenpalAssetOwner::get()),
+		RelayLocation::get(),
+		PenpalASender::get(),
+		fee_amount * 2,
+	);
+
+	// Transfer foreign asset, pay fees with WND.
+	let assets: Assets = vec![
+		(foreign_asset_location, asset_amount).into(),
+		(Parent, fee_amount).into(), // WND as fee.
+	]
+	.into();
+	let fee_asset_item = 1; // WND is the fee asset.
+
+	PenpalA::execute_with(|| {
+		let result = <PenpalA as PenpalAPallet>::PolkadotXcm::transfer_assets(
+			<PenpalA as Chain>::RuntimeOrigin::signed(PenpalASender::get()),
+			bx!(destination.into()),
+			bx!(beneficiary.into()),
+			bx!(assets.into()),
+			fee_asset_item,
+			WeightLimit::Unlimited,
+		);
+
+		// This should fail because WND fee would be reserve transferred.
+		assert_err!(
+			result,
+			DispatchError::Module(sp_runtime::ModuleError {
+				index: 31,
+				error: [21, 0, 0, 0], // InvalidAssetUnknownReserve.
+				message: Some("InvalidAssetUnknownReserve")
+			})
+		);
+	});
+}
+
+/// Test that `transfer_assets` works when neither asset nor fee is WND.
+#[test]
+fn transfer_assets_non_native_assets_work() {
+	let destination = PenpalA::sibling_location_of(PenpalB::para_id());
+	let beneficiary: Location =
+		AccountId32Junction { network: None, id: PenpalBReceiver::get().into() }.into();
+	let amount: Balance = 1_000_000_000_000; // A million USDT.
+
+	// Create foreign asset locations (both non-native).
+	let asset_location = Location::new(
+		1,
+		[
+			Parachain(AssetHubWestend::para_id().into()),
+			PalletInstance(ASSETS_PALLET_ID),
+			GeneralIndex(USDT_ID.into()), // USDT.
+		],
+	);
+
+	// Mint both USDT and WND on PenpalA, one for sending, the other for paying delivery fees.
+	PenpalA::mint_foreign_asset(
+		<PenpalA as Chain>::RuntimeOrigin::signed(PenpalAssetOwner::get()),
+		RelayLocation::get(),
+		PenpalASender::get(),
+		amount * 2,
+	);
+	PenpalA::mint_foreign_asset(
+		<PenpalA as Chain>::RuntimeOrigin::signed(PenpalAssetOwner::get()),
+		asset_location.clone(),
+		PenpalASender::get(),
+		amount * 2,
+	);
+
+	// Transfer non-native assets.
+	let assets: Assets = (asset_location, amount).into();
+	let fee_asset_item = 0;
+
+	PenpalA::execute_with(|| {
+		let result = <PenpalA as PenpalAPallet>::PolkadotXcm::transfer_assets(
+			<PenpalA as Chain>::RuntimeOrigin::signed(PenpalASender::get()),
+			bx!(destination.into()),
+			bx!(beneficiary.into()),
+			bx!(assets.into()),
+			fee_asset_item,
+			WeightLimit::Unlimited,
+		);
+
+		// This should succeed because neither asset is WND.
+		assert_ok!(result);
+	});
+}

polkadot/xcm/pallet-xcm/Cargo.toml

@@ -33,6 +33,7 @@ xcm-runtime-apis = { workspace = true }
 
 # marked optional, used in benchmarking
 frame-benchmarking = { optional = true, workspace = true }
+hex-literal = { workspace = true, default-features = false }
 pallet-balances = { optional = true, workspace = true }
 
 [dev-dependencies]

polkadot/xcm/pallet-xcm/src/lib.rs

@@ -25,6 +25,7 @@ mod mock;
 pub mod precompiles;
 #[cfg(test)]
 mod tests;
+mod transfer_assets_validation;
 
 pub mod migration;
 #[cfg(any(test, feature = "test-utils"))]
@@ -1489,6 +1490,16 @@ pub mod pallet {
 			let (fees_transfer_type, assets_transfer_type) =
 				Self::find_fee_and_assets_transfer_types(&assets, fee_asset_item, &dest)?;
 
+			// We check for network native asset reserve transfers in preparation for the Asset Hub
+			// Migration. This check will be removed after the migration and the determined
+			// reserve location adjusted accordingly. For more information, see https://github.com/paritytech/polkadot-sdk/issues/9054.
+			Self::ensure_network_asset_reserve_transfer_allowed(
+				&assets,
+				fee_asset_item,
+				&assets_transfer_type,
+				&fees_transfer_type,
+			)?;
+
 			Self::do_transfer_assets(
 				origin,
 				dest,