Utilize SDK types for native asset balance conversion (#424)

Utilize SDK types for native asset balance conversion in the Treasury
pallet setup.

This change does not introduce any behavioral changes; it simply updates
the code to use common types from the SDK.

- [x] Does not require a CHANGELOG entry

---------

Co-authored-by: Bastian Köcher <git@kchr.de>
Co-authored-by: fellowship-merge-bot[bot] <151052383+fellowship-merge-bot[bot]@users.noreply.github.com>

relay/kusama/src/lib.rs

@@ -41,7 +41,8 @@ use polkadot_primitives::{
 use polkadot_runtime_common::{
 	auctions, claims, crowdloan, impl_runtime_weights,
 	impls::{
-		DealWithFees, LocatableAssetConverter, VersionedLocatableAsset, VersionedLocationConverter,
+		ContainsParts as ContainsLocationParts, DealWithFees, LocatableAssetConverter,
+		VersionedLocatableAsset, VersionedLocationConverter,
 	},
 	paras_registrar, prod_or_fast, slots, BalanceToU256, BlockHashCount, BlockLength,
 	CurrencyToVote, SlowAdjustingFeeUpdate, U256ToBalance,
@@ -86,9 +87,10 @@ use frame_support::{
 	genesis_builder_helper::{build_state, get_preset},
 	parameter_types,
 	traits::{
-		fungible::HoldConsideration, ConstU32, Contains, EitherOf, EitherOfDiverse, Everything,
-		InstanceFilter, KeyOwnerProofSystem, LinearStoragePrice, PrivilegeCmp, ProcessMessage,
-		ProcessMessageError, StorageMapShim, WithdrawReasons,
+		fungible::HoldConsideration, tokens::UnityOrOuterConversion, ConstU32, ConstU8, EitherOf,
+		EitherOfDiverse, Everything, FromContains, InstanceFilter, KeyOwnerProofSystem,
+		LinearStoragePrice, PrivilegeCmp, ProcessMessage, ProcessMessageError, StorageMapShim,
+		WithdrawReasons,
 	},
 	weights::{ConstantMultiplier, WeightMeter, WeightToFee as _},
 	PalletId,
@@ -154,9 +156,6 @@ use governance::{
 	Treasurer, TreasurySpender,
 };
 
-// Implemented types.
-pub mod impls;
-
 #[cfg(test)]
 mod tests;
 
@@ -860,7 +859,7 @@ impl pallet_treasury::Config for Runtime {
 		LocatableAssetConverter,
 		VersionedLocationConverter,
 	>;
-	type BalanceConverter = impls::NativeOnSystemParachain<AssetRate>;
+	type BalanceConverter = AssetRateWithNative;
 	type PayoutPeriod = PayoutSpendPeriod;
 	#[cfg(feature = "runtime-benchmarks")]
 	type BenchmarkHelper = polkadot_runtime_common::impls::benchmarks::TreasuryArguments;
@@ -1614,6 +1613,19 @@ impl pallet_nomination_pools::Config for Runtime {
 	type AdminOrigin = EitherOf<EnsureRoot<AccountId>, StakingAdmin>;
 }
 
+/// The [frame_support::traits::tokens::ConversionFromAssetBalance] implementation provided by the
+/// `AssetRate` pallet instance, with additional decoration to identify different IDs/locations of
+/// native asset and provide a one-to-one balance conversion for them.
+pub type AssetRateWithNative = UnityOrOuterConversion<
+	ContainsLocationParts<
+		FromContains<
+			xcm_builder::IsChildSystemParachain<ParaId>,
+			xcm_builder::IsParentsOnly<ConstU8<1>>,
+		>,
+	>,
+	AssetRate,
+>;
+
 impl pallet_asset_rate::Config for Runtime {
 	type WeightInfo = weights::pallet_asset_rate::WeightInfo<Runtime>;
 	type RuntimeEvent = RuntimeEvent;

relay/kusama/tests/asset_rate.rs

@@ -0,0 +1,96 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot. If not, see <http://www.gnu.org/licenses/>.
+
+//! AssetRate pallet instance tests.
+
+use frame_support::traits::tokens::ConversionFromAssetBalance;
+use polkadot_runtime_common::impls::VersionedLocatableAsset;
+use staging_kusama_runtime::AssetRateWithNative;
+use xcm::prelude::*;
+
+#[test]
+fn native_asset_rate_works() {
+	sp_io::TestExternalities::default().execute_with(|| {
+		// success: native asset on Asset Hub as xcm v4 location
+		let native = VersionedLocatableAsset::V4 {
+			location: Location::new(0, [Parachain(1000)]),
+			asset_id: Location::parent().into(),
+		};
+		let actual = AssetRateWithNative::from_asset_balance(100, native).unwrap();
+		assert_eq!(actual, 100);
+
+		// success: native asset on Asset Hub as xcm v3 location
+		let native = VersionedLocatableAsset::V3 {
+			location: xcm::v3::Location::new(
+				0,
+				xcm::v3::Junctions::X1(xcm::v3::Junction::Parachain(1000)),
+			),
+			asset_id: xcm::v3::Location::parent().into(),
+		};
+		let actual = AssetRateWithNative::from_asset_balance(100, native).unwrap();
+		assert_eq!(actual, 100);
+
+		// success: native asset on People as xcm v4 location
+		let native = VersionedLocatableAsset::V4 {
+			location: Location::new(0, [Parachain(1004)]),
+			asset_id: Location::parent().into(),
+		};
+		let actual = AssetRateWithNative::from_asset_balance(100, native).unwrap();
+		assert_eq!(actual, 100);
+
+		// success: native asset on People as xcm v3 location
+		let native = VersionedLocatableAsset::V3 {
+			location: xcm::v3::Location::new(
+				0,
+				xcm::v3::Junctions::X1(xcm::v3::Junction::Parachain(1004)),
+			),
+			asset_id: xcm::v3::Location::parent().into(),
+		};
+		let actual = AssetRateWithNative::from_asset_balance(100, native).unwrap();
+		assert_eq!(actual, 100);
+
+		// failure: native asset on non system chain as xcm v4 location
+		let native_non_system = VersionedLocatableAsset::V4 {
+			location: Location::new(0, [Parachain(2000)]),
+			asset_id: Location::parent().into(),
+		};
+		assert!(AssetRateWithNative::from_asset_balance(100, native_non_system).is_err());
+
+		// failure: native asset on non system chain as xcm v3 location
+		let native_non_system = VersionedLocatableAsset::V3 {
+			location: xcm::v3::Location::new(
+				0,
+				xcm::v3::Junctions::X1(xcm::v3::Junction::Parachain(2000)),
+			),
+			asset_id: xcm::v3::Location::parent().into(),
+		};
+		assert!(AssetRateWithNative::from_asset_balance(100, native_non_system).is_err());
+
+		// failure: some asset on Asset Hub as xcm v4 location
+		let non_native = VersionedLocatableAsset::V4 {
+			location: Location::new(0, [Parachain(2000)]),
+			asset_id: Location::new(0, [PalletInstance(50), GeneralIndex(1984)]).into(),
+		};
+		assert!(AssetRateWithNative::from_asset_balance(100, non_native).is_err());
+
+		// failure: native asset with invalid system chain location as xcm v4 location
+		let native_non_system = VersionedLocatableAsset::V4 {
+			location: Location::new(1, [Parachain(1000)]),
+			asset_id: Location::parent().into(),
+		};
+		assert!(AssetRateWithNative::from_asset_balance(100, native_non_system).is_err());
+	});
+}

relay/polkadot/src/impls.rs

@@ -14,53 +14,9 @@
 // You should have received a copy of the GNU General Public License
 // along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
 
-use super::*;
-use core::marker::PhantomData;
-use frame_support::traits::{tokens::ConversionFromAssetBalance, Contains};
-use polkadot_primitives::Id as ParaId;
-use xcm_builder::IsChildSystemParachain;
-
-// TODO: replace by types from polkadot-sdk https://github.com/paritytech/polkadot-sdk/pull/3659
-/// Determines if the given `asset_kind` is a native asset. If it is, returns the balance without
-/// conversion; otherwise, delegates to the implementation specified by `I`.
-///
-/// Example where the `asset_kind` represents the native asset:
-/// - location: (1, Parachain(1000)), // location of a Sibling Parachain;
-/// - asset_id: (1, Here), // the asset id in the context of `asset_kind.location`;
-pub struct NativeOnSystemParachain<I>(PhantomData<I>);
-impl<I> ConversionFromAssetBalance<Balance, VersionedLocatableAsset, Balance>
-	for NativeOnSystemParachain<I>
-where
-	I: ConversionFromAssetBalance<Balance, VersionedLocatableAsset, Balance>,
-{
-	type Error = ();
-	fn from_asset_balance(
-		balance: Balance,
-		asset_kind: VersionedLocatableAsset,
-	) -> Result<Balance, Self::Error> {
-		use VersionedLocatableAsset::*;
-		let (location, asset_id) = match asset_kind.clone() {
-			V3 { location, asset_id } => (location.try_into()?, asset_id.try_into()?),
-			V4 { location, asset_id } => (location, asset_id),
-		};
-		if asset_id.0.contains_parents_only(1) &&
-			IsChildSystemParachain::<ParaId>::contains(&location)
-		{
-			Ok(balance)
-		} else {
-			I::from_asset_balance(balance, asset_kind).map_err(|_| ())
-		}
-	}
-	#[cfg(feature = "runtime-benchmarks")]
-	fn ensure_successful(asset_kind: VersionedLocatableAsset) {
-		I::ensure_successful(asset_kind)
-	}
-}
-
 #[cfg(feature = "runtime-benchmarks")]
 pub mod benchmarks {
-	use super::{xcm_config::CheckAccount, ExistentialDeposit};
-	use crate::Balances;
+	use crate::{xcm_config::CheckAccount, Balances, ExistentialDeposit};
 	use frame_support::{
 		dispatch::RawOrigin,
 		traits::{Currency, EnsureOrigin},

relay/polkadot/src/lib.rs

@@ -24,7 +24,8 @@ use pallet_transaction_payment::FungibleAdapter;
 use polkadot_runtime_common::{
 	auctions, claims, crowdloan, impl_runtime_weights,
 	impls::{
-		DealWithFees, LocatableAssetConverter, VersionedLocatableAsset, VersionedLocationConverter,
+		ContainsParts as ContainsLocationParts, DealWithFees, LocatableAssetConverter,
+		VersionedLocatableAsset, VersionedLocationConverter,
 	},
 	paras_registrar, prod_or_fast, slots,
 	traits::OnSwap,
@@ -62,9 +63,10 @@ use frame_support::{
 	genesis_builder_helper::{build_state, get_preset},
 	parameter_types,
 	traits::{
-		fungible::HoldConsideration, ConstU32, EitherOf, EitherOfDiverse, Everything, Get,
-		InstanceFilter, KeyOwnerProofSystem, LinearStoragePrice, OnRuntimeUpgrade, PrivilegeCmp,
-		ProcessMessage, ProcessMessageError, WithdrawReasons,
+		fungible::HoldConsideration, tokens::UnityOrOuterConversion, ConstU32, ConstU8, EitherOf,
+		EitherOfDiverse, Everything, FromContains, Get, InstanceFilter, KeyOwnerProofSystem,
+		LinearStoragePrice, OnRuntimeUpgrade, PrivilegeCmp, ProcessMessage, ProcessMessageError,
+		WithdrawReasons,
 	},
 	weights::{
 		constants::{WEIGHT_PROOF_SIZE_PER_KB, WEIGHT_REF_TIME_PER_MICROS},
@@ -826,7 +828,7 @@ impl pallet_treasury::Config for Runtime {
 		LocatableAssetConverter,
 		VersionedLocationConverter,
 	>;
-	type BalanceConverter = impls::NativeOnSystemParachain<AssetRate>;
+	type BalanceConverter = AssetRateWithNative;
 	type PayoutPeriod = PayoutSpendPeriod;
 	#[cfg(feature = "runtime-benchmarks")]
 	type BenchmarkHelper = polkadot_runtime_common::impls::benchmarks::TreasuryArguments;
@@ -1554,6 +1556,19 @@ impl pallet_state_trie_migration::Config for Runtime {
 	type MaxKeyLen = MigrationMaxKeyLen;
 }
 
+/// The [frame_support::traits::tokens::ConversionFromAssetBalance] implementation provided by the
+/// `AssetRate` pallet instance, with additional decoration to identify different IDs/locations of
+/// native asset and provide a one-to-one balance conversion for them.
+pub type AssetRateWithNative = UnityOrOuterConversion<
+	ContainsLocationParts<
+		FromContains<
+			xcm_builder::IsChildSystemParachain<ParaId>,
+			xcm_builder::IsParentsOnly<ConstU8<1>>,
+		>,
+	>,
+	AssetRate,
+>;
+
 impl pallet_asset_rate::Config for Runtime {
 	type WeightInfo = weights::pallet_asset_rate::WeightInfo<Runtime>;
 	type RuntimeEvent = RuntimeEvent;