extend XCM FeeManager

cumulus/parachains/runtimes/assets/asset-hub-rococo/src/xcm_config.rs

@@ -53,7 +53,7 @@ use xcm_builder::{
 	SiblingParachainConvertsVia, SignedAccountId32AsNative, SignedToAccountId32,
 	SovereignSignedViaLocation, StartsWith, StartsWithExplicitGlobalConsensus, TakeWeightCredit,
 	TrailingSetTopicAsId, UsingComponents, WeightInfoBounds, WithComputedOrigin, WithUniqueTopic,
-	XcmFeesToAccount,
+	XcmFeeManagerFromComponents, XcmFeeToAccount,
 };
 use xcm_executor::{traits::WithOriginFilter, XcmExecutor};
 
@@ -75,7 +75,7 @@ parameter_types! {
 		PalletInstance(<PoolAssets as PalletInfoAccess>::index() as u8).into();
 	pub CheckingAccount: AccountId = PolkadotXcm::check_account();
 	pub const GovernanceLocation: MultiLocation = MultiLocation::parent();
-	pub TreasuryAccount: Option<AccountId> = Some(TREASURY_PALLET_ID.into_account_truncating());
+	pub TreasuryAccount: AccountId = TREASURY_PALLET_ID.into_account_truncating();
 }
 
 /// Adapter for resolving `NetworkId` based on `pub storage Flavor: RuntimeFlavor`.
@@ -614,7 +614,10 @@ impl xcm_executor::Config for XcmConfig {
 	type MaxAssetsIntoHolding = MaxAssetsIntoHolding;
 	type AssetLocker = ();
 	type AssetExchanger = ();
-	type FeeManager = XcmFeesToAccount<Self, WaivedLocations, AccountId, TreasuryAccount>;
+	type FeeManager = XcmFeeManagerFromComponents<
+		WaivedLocations,
+		XcmFeeToAccount<Self::AssetTransactor, AccountId, TreasuryAccount>,
+	>;
 	type MessageExporter = ();
 	type UniversalAliases =
 		(bridging::to_wococo::UniversalAliases, bridging::to_rococo::UniversalAliases);

cumulus/parachains/runtimes/assets/asset-hub-westend/src/xcm_config.rs

@@ -52,7 +52,7 @@ use xcm_builder::{
 	SiblingParachainConvertsVia, SignedAccountId32AsNative, SignedToAccountId32,
 	SovereignSignedViaLocation, StartsWith, StartsWithExplicitGlobalConsensus, TakeWeightCredit,
 	TrailingSetTopicAsId, UsingComponents, WeightInfoBounds, WithComputedOrigin, WithUniqueTopic,
-	XcmFeesToAccount,
+	XcmFeeManagerFromComponents, XcmFeeToAccount,
 };
 use xcm_executor::{traits::WithOriginFilter, XcmExecutor};
 
@@ -73,7 +73,7 @@ parameter_types! {
 	pub PoolAssetsPalletLocation: MultiLocation =
 		PalletInstance(<PoolAssets as PalletInfoAccess>::index() as u8).into();
 	pub CheckingAccount: AccountId = PolkadotXcm::check_account();
-	pub TreasuryAccount: Option<AccountId> = Some(TREASURY_PALLET_ID.into_account_truncating());
+	pub TreasuryAccount: AccountId = TREASURY_PALLET_ID.into_account_truncating();
 }
 
 /// Type for specifying how a `MultiLocation` can be converted into an `AccountId`. This is used
@@ -570,7 +570,10 @@ impl xcm_executor::Config for XcmConfig {
 	type MaxAssetsIntoHolding = MaxAssetsIntoHolding;
 	type AssetLocker = ();
 	type AssetExchanger = ();
-	type FeeManager = XcmFeesToAccount<Self, WaivedLocations, AccountId, TreasuryAccount>;
+	type FeeManager = XcmFeeManagerFromComponents<
+		WaivedLocations,
+		XcmFeeToAccount<Self::AssetTransactor, AccountId, TreasuryAccount>,
+	>;
 	type MessageExporter = ();
 	type UniversalAliases = Nothing;
 	type CallDispatcher = WithOriginFilter<SafeCallFilter>;

cumulus/parachains/runtimes/bridge-hubs/bridge-hub-rococo/src/xcm_config.rs

@@ -24,8 +24,8 @@ use crate::{
 		BridgeGrandpaRococoInstance, BridgeGrandpaWococoInstance, DeliveryRewardInBalance,
 		RequiredStakeForStakeAndSlash,
 	},
-	bridge_hub_rococo_config::ToBridgeHubWococoHaulBlobExporter,
-	bridge_hub_wococo_config::ToBridgeHubRococoHaulBlobExporter,
+	bridge_hub_rococo_config::{ToBridgeHubWococoHaulBlobExporter, WococoGlobalConsensusNetwork},
+	bridge_hub_wococo_config::{RococoGlobalConsensusNetwork, ToBridgeHubRococoHaulBlobExporter},
 };
 use frame_support::{
 	match_types, parameter_types,
@@ -51,7 +51,7 @@ use xcm_builder::{
 	ParentIsPreset, RelayChainAsNative, SiblingParachainAsNative, SiblingParachainConvertsVia,
 	SignedAccountId32AsNative, SignedToAccountId32, SovereignSignedViaLocation, TakeWeightCredit,
 	TrailingSetTopicAsId, UsingComponents, WeightInfoBounds, WithComputedOrigin, WithUniqueTopic,
-	XcmFeesToAccount,
+	XcmExportFeeToAccount, XcmFeeManagerFromComponents, XcmFeeToAccount,
 };
 use xcm_executor::{
 	traits::{ExportXcm, WithOriginFilter},
@@ -66,7 +66,7 @@ parameter_types! {
 		X2(GlobalConsensus(RelayNetwork::get()), Parachain(ParachainInfo::parachain_id().into()));
 	pub const MaxInstructions: u32 = 100;
 	pub const MaxAssetsIntoHolding: u32 = 64;
-	pub TreasuryAccount: Option<AccountId> = Some(TREASURY_PALLET_ID.into_account_truncating());
+	pub TreasuryAccount: AccountId = TREASURY_PALLET_ID.into_account_truncating();
 }
 
 /// Adapter for resolving `NetworkId` based on `pub storage Flavor: RuntimeFlavor`.
@@ -282,7 +282,26 @@ impl xcm_executor::Config for XcmConfig {
 	type SubscriptionService = PolkadotXcm;
 	type PalletInstancesInfo = AllPalletsWithSystem;
 	type MaxAssetsIntoHolding = MaxAssetsIntoHolding;
-	type FeeManager = XcmFeesToAccount<Self, WaivedLocations, AccountId, TreasuryAccount>;
+	type FeeManager = XcmFeeManagerFromComponents<
+		WaivedLocations,
+		// Just showcasing that we can direct fees from different bridges to different accounts.
+		// We use the `TreasuryAccount` as the receiver account in any case by design.
+		(
+			XcmExportFeeToAccount<
+				Self::AssetTransactor,
+				RococoGlobalConsensusNetwork,
+				AccountId,
+				TreasuryAccount,
+			>,
+			XcmExportFeeToAccount<
+				Self::AssetTransactor,
+				WococoGlobalConsensusNetwork,
+				AccountId,
+				TreasuryAccount,
+			>,
+			XcmFeeToAccount<Self::AssetTransactor, AccountId, TreasuryAccount>,
+		),
+	>;
 	type MessageExporter = BridgeHubRococoOrBridgeHubWococoSwitchExporter;
 	type UniversalAliases = Nothing;
 	type CallDispatcher = WithOriginFilter<SafeCallFilter>;

cumulus/parachains/runtimes/contracts/contracts-rococo/src/xcm_config.rs

@@ -41,7 +41,7 @@ use xcm_builder::{
 	NativeAsset, ParentAsSuperuser, ParentIsPreset, RelayChainAsNative, SiblingParachainAsNative,
 	SiblingParachainConvertsVia, SignedAccountId32AsNative, SignedToAccountId32,
 	SovereignSignedViaLocation, TakeWeightCredit, TrailingSetTopicAsId, UsingComponents,
-	WithComputedOrigin, WithUniqueTopic, XcmFeesToAccount,
+	WithComputedOrigin, WithUniqueTopic, XcmFeeManagerFromComponents, XcmFeeToAccount,
 };
 use xcm_executor::XcmExecutor;
 
@@ -51,7 +51,7 @@ parameter_types! {
 	pub RelayChainOrigin: RuntimeOrigin = cumulus_pallet_xcm::Origin::Relay.into();
 	pub UniversalLocation: InteriorMultiLocation = Parachain(ParachainInfo::parachain_id().into()).into();
 	pub const ExecutiveBody: BodyId = BodyId::Executive;
-	pub TreasuryAccount: Option<AccountId> = Some(TREASURY_PALLET_ID.into_account_truncating());
+	pub TreasuryAccount: AccountId = TREASURY_PALLET_ID.into_account_truncating();
 }
 
 /// We allow root and the Relay Chain council to execute privileged collator selection operations.
@@ -174,11 +174,9 @@ impl xcm_executor::Config for XcmConfig {
 	type MaxAssetsIntoHolding = ConstU32<8>;
 	type AssetLocker = ();
 	type AssetExchanger = ();
-	type FeeManager = XcmFeesToAccount<
-		Self,
+	type FeeManager = XcmFeeManagerFromComponents<
 		RelayOrOtherSystemParachains<SystemParachains, Runtime>,
-		AccountId,
-		TreasuryAccount,
+		XcmFeeToAccount<Self::AssetTransactor, AccountId, TreasuryAccount>,
 	>;
 	type MessageExporter = ();
 	type UniversalAliases = Nothing;

polkadot/runtime/rococo/src/xcm_config.rs

@@ -43,7 +43,8 @@ use xcm_builder::{
 	DescribeFamily, FixedWeightBounds, HashedDescription, IsChildSystemParachain, IsConcrete,
 	MintLocation, OriginToPluralityVoice, SignedAccountId32AsNative, SignedToAccountId32,
 	SovereignSignedViaLocation, TakeWeightCredit, TrailingSetTopicAsId, UsingComponents,
-	WeightInfoBounds, WithComputedOrigin, WithUniqueTopic, XcmFeesToAccount,
+	WeightInfoBounds, WithComputedOrigin, WithUniqueTopic, XcmFeeManagerFromComponents,
+	XcmFeeToAccount,
 };
 use xcm_executor::XcmExecutor;
 
@@ -53,7 +54,7 @@ parameter_types! {
 	pub UniversalLocation: InteriorMultiLocation = ThisNetwork::get().into();
 	pub CheckAccount: AccountId = XcmPallet::check_account();
 	pub LocalCheckAccount: (AccountId, MintLocation) = (CheckAccount::get(), MintLocation::Local);
-	pub TreasuryAccount: Option<AccountId> = Some(Treasury::account_id());
+	pub TreasuryAccount: AccountId = Treasury::account_id();
 }
 
 pub type LocationConverter = (
@@ -191,7 +192,10 @@ impl xcm_executor::Config for XcmConfig {
 	type SubscriptionService = XcmPallet;
 	type PalletInstancesInfo = AllPalletsWithSystem;
 	type MaxAssetsIntoHolding = MaxAssetsIntoHolding;
-	type FeeManager = XcmFeesToAccount<Self, SystemParachains, AccountId, TreasuryAccount>;
+	type FeeManager = XcmFeeManagerFromComponents<
+		SystemParachains,
+		XcmFeeToAccount<Self::AssetTransactor, AccountId, TreasuryAccount>,
+	>;
 	type MessageExporter = ();
 	type UniversalAliases = Nothing;
 	type CallDispatcher = RuntimeCall;

polkadot/runtime/westend/src/xcm_config.rs

@@ -44,7 +44,7 @@ use xcm_builder::{
 	DescribeFamily, HashedDescription, IsConcrete, MintLocation, OriginToPluralityVoice,
 	SignedAccountId32AsNative, SignedToAccountId32, SovereignSignedViaLocation, TakeWeightCredit,
 	TrailingSetTopicAsId, UsingComponents, WeightInfoBounds, WithComputedOrigin, WithUniqueTopic,
-	XcmFeesToAccount,
+	XcmFeeManagerFromComponents, XcmFeeToAccount,
 };
 use xcm_executor::XcmExecutor;
 
@@ -54,7 +54,7 @@ parameter_types! {
 	pub const UniversalLocation: InteriorMultiLocation = X1(GlobalConsensus(ThisNetwork::get()));
 	pub CheckAccount: AccountId = XcmPallet::check_account();
 	pub LocalCheckAccount: (AccountId, MintLocation) = (CheckAccount::get(), MintLocation::Local);
-	pub TreasuryAccount: Option<AccountId> = Some(Treasury::account_id());
+	pub TreasuryAccount: AccountId = Treasury::account_id();
 	/// The asset ID for the asset that we use to pay for message delivery fees.
 	pub FeeAssetId: AssetId = Concrete(TokenLocation::get());
 	/// The base fee for the message delivery fees.
@@ -185,7 +185,10 @@ impl xcm_executor::Config for XcmConfig {
 	type SubscriptionService = XcmPallet;
 	type PalletInstancesInfo = AllPalletsWithSystem;
 	type MaxAssetsIntoHolding = MaxAssetsIntoHolding;
-	type FeeManager = XcmFeesToAccount<Self, SystemParachains, AccountId, TreasuryAccount>;
+	type FeeManager = XcmFeeManagerFromComponents<
+		SystemParachains,
+		XcmFeeToAccount<Self::AssetTransactor, AccountId, TreasuryAccount>,
+	>;
 	type MessageExporter = ();
 	type UniversalAliases = Nothing;
 	type CallDispatcher = RuntimeCall;

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

@@ -34,7 +34,7 @@ use xcm_builder::{
 	AllowTopLevelPaidExecutionFrom, Case, ChildParachainAsNative, ChildParachainConvertsVia,
 	ChildSystemParachainAsSuperuser, CurrencyAdapter as XcmCurrencyAdapter, FixedRateOfFungible,
 	FixedWeightBounds, IsConcrete, SignedAccountId32AsNative, SignedToAccountId32,
-	SovereignSignedViaLocation, TakeWeightCredit, XcmFeesToAccount,
+	SovereignSignedViaLocation, TakeWeightCredit, XcmFeeManagerFromComponents, XcmFeeToAccount,
 };
 use xcm_executor::XcmExecutor;
 
@@ -343,11 +343,9 @@ impl xcm_executor::Config for XcmConfig {
 	type SubscriptionService = XcmPallet;
 	type PalletInstancesInfo = AllPalletsWithSystem;
 	type MaxAssetsIntoHolding = MaxAssetsIntoHolding;
-	type FeeManager = XcmFeesToAccount<
-		Self,
+	type FeeManager = XcmFeeManagerFromComponents<
 		EverythingBut<XcmFeesNotWaivedLocations>,
-		AccountId,
-		XcmFeesTargetAccount,
+		XcmFeeToAccount<Self::AssetTransactor, AccountId, XcmFeesTargetAccount>,
 	>;
 	type MessageExporter = ();
 	type UniversalAliases = Nothing;

polkadot/xcm/xcm-builder/src/fee_handling.rs

@@ -17,42 +17,87 @@
 use core::marker::PhantomData;
 use frame_support::traits::{Contains, Get};
 use xcm::prelude::*;
-use xcm_executor::traits::{FeeManager, FeeReason, TransactAsset};
+use xcm_executor::traits::{FeeManager, FeeReason, HandleFee, TransactAsset};
 
-/// A `FeeManager` implementation that simply deposits the fees handled into a specific on-chain
+/// A `FeeManager` implementation that permits the specified `WaivedLocations` to not pay for fees
+/// and that uses the provided `HandleFee` implementation otherwise.
+pub struct XcmFeeManagerFromComponents<WaivedLocations, HandleFee>(
+	PhantomData<(WaivedLocations, HandleFee)>,
+);
+impl<WaivedLocations: Contains<MultiLocation>, FeeHandler: HandleFee> FeeManager
+	for XcmFeeManagerFromComponents<WaivedLocations, FeeHandler>
+{
+	type HandleFee = FeeHandler;
+
+	fn is_waived(origin: Option<&MultiLocation>, _: FeeReason) -> bool {
+		let Some(loc) = origin else { return false };
+		WaivedLocations::contains(loc)
+	}
+}
+
+/// A `HandleFee` implementation that simply deposits the fees into a specific on-chain
 /// `ReceiverAccount`.
 ///
-/// It reuses the `AssetTransactor` configured on the XCM executor to deposit fee assets, and also
-/// permits specifying `WaivedLocations` for locations that are privileged to not pay for fees. If
+/// It reuses the `AssetTransactor` configured on the XCM executor to deposit fee assets. If
 /// the `AssetTransactor` returns an error while calling `deposit_asset`, then a warning will be
 /// logged.
-pub struct XcmFeesToAccount<XcmConfig, WaivedLocations, AccountId, ReceiverAccount>(
-	PhantomData<(XcmConfig, WaivedLocations, AccountId, ReceiverAccount)>,
+pub struct XcmFeeToAccount<AssetTransactor, AccountId, ReceiverAccount>(
+	PhantomData<(AssetTransactor, AccountId, ReceiverAccount)>,
 );
+
 impl<
-		XcmConfig: xcm_executor::Config,
-		WaivedLocations: Contains<MultiLocation>,
+		AssetTransactor: TransactAsset,
 		AccountId: Clone + Into<[u8; 32]>,
-		ReceiverAccount: Get<Option<AccountId>>,
-	> FeeManager for XcmFeesToAccount<XcmConfig, WaivedLocations, AccountId, ReceiverAccount>
+		ReceiverAccount: Get<AccountId>,
+	> HandleFee for XcmFeeToAccount<AssetTransactor, AccountId, ReceiverAccount>
 {
-	fn is_waived(origin: Option<&MultiLocation>, _: FeeReason) -> bool {
-		let Some(loc) = origin else { return false };
-		WaivedLocations::contains(loc)
+	fn handle_fee(
+		fee: MultiAssets,
+		context: Option<&XcmContext>,
+		_reason: FeeReason,
+	) -> MultiAssets {
+		let receiver = ReceiverAccount::get();
+		let dest = AccountId32 { network: None, id: receiver.into() }.into();
+		for asset in fee.into_inner() {
+			if let Err(e) = AssetTransactor::deposit_asset(&asset, &dest, context) {
+				log::trace!(
+					target: "xcm::fees",
+					"`AssetTransactor::deposit_asset` returned error: {:?}. Skipping fees: {:?}. \
+					They might be burned.",
+					e, asset,
+				);
+			}
+		}
+
+		MultiAssets::new()
 	}
+}
 
-	fn handle_fee(fees: MultiAssets, context: Option<&XcmContext>) {
-		if let Some(receiver) = ReceiverAccount::get() {
-			let dest = AccountId32 { network: None, id: receiver.into() }.into();
-			for asset in fees.into_inner() {
-				if let Err(e) = XcmConfig::AssetTransactor::deposit_asset(&asset, &dest, context) {
-					log::trace!(
-						target: "xcm::fees",
-						"`AssetTransactor::deposit_asset` returned error: {:?}, burning fees: {:?}",
-						e, asset,
-					);
-				}
-			}
+/// A `HandleFee` implementation that simply deposits the fees for
+/// `ExportMessage { network: BridgedNetwork::get(), .. }` XCM instructions into a specific
+/// on-chain `ReceiverAccount`.
+pub struct XcmExportFeeToAccount<AssetTransactor, BridgedNetwork, AccountId, ReceiverAccount>(
+	PhantomData<(AssetTransactor, BridgedNetwork, AccountId, ReceiverAccount)>,
+);
+
+impl<
+		AssetTransactor: TransactAsset,
+		BridgedNetwork: Get<NetworkId>,
+		AccountId: Clone + Into<[u8; 32]>,
+		ReceiverAccount: Get<AccountId>,
+	> HandleFee for XcmExportFeeToAccount<AssetTransactor, BridgedNetwork, AccountId, ReceiverAccount>
+{
+	fn handle_fee(
+		fee: MultiAssets,
+		context: Option<&XcmContext>,
+		reason: FeeReason,
+	) -> MultiAssets {
+		match reason {
+			FeeReason::Export(bridged_network) if bridged_network == BridgedNetwork::get() =>
+				XcmFeeToAccount::<AssetTransactor, AccountId, ReceiverAccount>::handle_fee(
+					fee, context, reason,
+				),
+			_ => fee,
 		}
 	}
 }

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

@@ -68,7 +68,7 @@ mod currency_adapter;
 pub use currency_adapter::CurrencyAdapter;
 
 mod fee_handling;
-pub use fee_handling::XcmFeesToAccount;
+pub use fee_handling::{XcmExportFeeToAccount, XcmFeeManagerFromComponents, XcmFeeToAccount};
 
 mod fungibles_adapter;
 pub use fungibles_adapter::{

polkadot/xcm/xcm-builder/src/tests/mock.rs

@@ -523,10 +523,11 @@ pub fn set_fee_waiver(waived: Vec<FeeReason>) {
 
 pub struct TestFeeManager;
 impl FeeManager for TestFeeManager {
+	type HandleFee = ();
+
 	fn is_waived(_: Option<&MultiLocation>, r: FeeReason) -> bool {
 		IS_WAIVED.with(|l| l.borrow().contains(&r))
 	}
-	fn handle_fee(_: MultiAssets, _: Option<&XcmContext>) {}
 }
 
 #[derive(Clone, Eq, PartialEq, Debug)]