XCM: Use matcher API in DenyReserveAssetTransferToRelay

parachain-template/runtime/src/xcm_config.rs

@@ -2,7 +2,7 @@ use super::{
 	AccountId, AllPalletsWithSystem, Balances, ParachainInfo, ParachainSystem, PolkadotXcm,
 	Runtime, RuntimeCall, RuntimeEvent, RuntimeOrigin, WeightToFee, XcmpQueue,
 };
-use core::marker::PhantomData;
+use core::{marker::PhantomData, ops::ControlFlow};
 use frame_support::{
 	log, match_types, parameter_types,
 	traits::{ConstU32, Everything, Nothing},
@@ -11,7 +11,7 @@ use frame_support::{
 use pallet_xcm::XcmPassthrough;
 use polkadot_parachain::primitives::Sibling;
 use polkadot_runtime_common::impls::ToAuthor;
-use xcm::latest::prelude::*;
+use xcm::{latest::prelude::*, CreateMatcher, MatchXcm};
 use xcm_builder::{
 	AccountId32Aliases, AllowExplicitUnpaidExecutionFrom, AllowTopLevelPaidExecutionFrom,
 	CurrencyAdapter, EnsureXcmOrigin, FixedWeightBounds, IsConcrete, NativeAsset, ParentIsPreset,
@@ -122,32 +122,36 @@ impl ShouldExecute for DenyReserveTransferToRelayChain {
 		_max_weight: Weight,
 		_weight_credit: &mut Weight,
 	) -> Result<(), ()> {
-		if message.iter().any(|inst| {
-			matches!(
-				inst,
+		message.matcher().match_next_inst_while(
+			|_| true,
+			|inst| match inst {
 				InitiateReserveWithdraw {
 					reserve: MultiLocation { parents: 1, interior: Here },
 					..
-				} | DepositReserveAsset { dest: MultiLocation { parents: 1, interior: Here }, .. } |
-					TransferReserveAsset {
-						dest: MultiLocation { parents: 1, interior: Here },
-						..
-					}
-			)
-		}) {
-			return Err(()) // Deny
-		}
-
-		// An unexpected reserve transfer has arrived from the Relay Chain. Generally, `IsReserve`
-		// should not allow this, but we just log it here.
-		if matches!(origin, MultiLocation { parents: 1, interior: Here }) &&
-			message.iter().any(|inst| matches!(inst, ReserveAssetDeposited { .. }))
-		{
-			log::warn!(
-				target: "xcm::barriers",
-				"Unexpected ReserveAssetDeposited from the Relay Chain",
-			);
-		}
+				} |
+				DepositReserveAsset {
+					dest: MultiLocation { parents: 1, interior: Here }, ..
+				} |
+				TransferReserveAsset {
+					dest: MultiLocation { parents: 1, interior: Here }, ..
+				} => {
+					Err(()) // Deny
+				},
+				// An unexpected reserve transfer has arrived from the Relay Chain. Generally,
+				// `IsReserve` should not allow this, but we just log it here.
+				ReserveAssetDeposited { .. }
+					if matches!(origin, MultiLocation { parents: 1, interior: Here }) =>
+				{
+					log::warn!(
+						target: "xcm::barrier",
+						"Unexpected ReserveAssetDeposited from the Relay Chain",
+					);
+					Ok(ControlFlow::Continue(()))
+				},
+				_ => Ok(ControlFlow::Continue(())),
+			},
+		)?;
+
 		// Permit everything else
 		Ok(())
 	}

parachains/common/src/xcm_config.rs

@@ -1,12 +1,12 @@
 use crate::impls::AccountIdOf;
-use core::marker::PhantomData;
+use core::{marker::PhantomData, ops::ControlFlow};
 use frame_support::{
 	log,
 	traits::{fungibles::Inspect, tokens::BalanceConversion, ContainsPair},
 	weights::{Weight, WeightToFee, WeightToFeePolynomial},
 };
 use sp_runtime::traits::Get;
-use xcm::latest::prelude::*;
+use xcm::{latest::prelude::*, CreateMatcher, MatchXcm};
 use xcm_executor::traits::ShouldExecute;
 
 //TODO: move DenyThenTry to polkadot's xcm module.
@@ -42,32 +42,38 @@ impl ShouldExecute for DenyReserveTransferToRelayChain {
 		_max_weight: Weight,
 		_weight_credit: &mut Weight,
 	) -> Result<(), ()> {
-		if message.iter().any(|inst| {
-			matches!(
-				inst,
+		message.matcher().match_next_inst_while(
+			|_| true,
+			|inst| match inst {
 				InitiateReserveWithdraw {
 					reserve: MultiLocation { parents: 1, interior: Here },
 					..
-				} | DepositReserveAsset { dest: MultiLocation { parents: 1, interior: Here }, .. } |
-					TransferReserveAsset {
-						dest: MultiLocation { parents: 1, interior: Here },
-						..
-					}
-			)
-		}) {
-			return Err(()) // Deny
-		}
+				} |
+				DepositReserveAsset {
+					dest: MultiLocation { parents: 1, interior: Here }, ..
+				} |
+				TransferReserveAsset {
+					dest: MultiLocation { parents: 1, interior: Here }, ..
+				} => {
+					Err(()) // Deny
+				},
+
+				// An unexpected reserve transfer has arrived from the Relay Chain. Generally,
+				// `IsReserve` should not allow this, but we just log it here.
+				ReserveAssetDeposited { .. }
+					if matches!(origin, MultiLocation { parents: 1, interior: Here }) =>
+				{
+					log::warn!(
+						target: "xcm::barrier",
+						"Unexpected ReserveAssetDeposited from the Relay Chain",
+					);
+					Ok(ControlFlow::Continue(()))
+				},
+
+				_ => Ok(ControlFlow::Continue(())),
+			},
+		)?;
 
-		// An unexpected reserve transfer has arrived from the Relay Chain. Generally, `IsReserve`
-		// should not allow this, but we just log it here.
-		if matches!(origin, MultiLocation { parents: 1, interior: Here }) &&
-			message.iter().any(|inst| matches!(inst, ReserveAssetDeposited { .. }))
-		{
-			log::warn!(
-				target: "xcm::barriers",
-				"Unexpected ReserveAssetDeposited from the Relay Chain",
-			);
-		}
 		// Permit everything else
 		Ok(())
 	}