Add claim_assets extrinsic to pallet-xcm (#3403)

If an XCM execution fails or ends with leftover assets, these will be
trapped.
In order to claim them, a custom XCM has to be executed, with the
`ClaimAsset` instruction.
However, arbitrary XCM execution is not allowed everywhere yet and XCM
itself is still not easy enough to use for users out there with trapped
assets.
This new extrinsic in `pallet-xcm` will allow these users to easily
claim their assets, without concerning themselves with writing arbitrary
XCMs.

Part of fixing #3495

---------

Co-authored-by: command-bot <>
Co-authored-by: Adrian Catangiu <adrian@parity.io>

Author: franciscoaguirre

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

@@ -1475,6 +1475,13 @@ impl_runtime_apis! {
 					});
 					Some((assets, fee_index as u32, dest, verify))
 				}
+
+				fn get_asset() -> Asset {
+					Asset {
+						id: AssetId(Location::parent()),
+						fun: Fungible(ExistentialDeposit::get()),
+					}
+				}
 			}
 
 			impl XcmBridgeHubRouterConfig<ToWestendXcmRouterInstance> for Runtime {

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

@@ -16,10 +16,10 @@
 
 //! Autogenerated weights for `pallet_xcm`
 //!
-//! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 4.0.0-dev
-//! DATE: 2023-12-05, STEPS: `50`, REPEAT: `20`, LOW RANGE: `[]`, HIGH RANGE: `[]`
+//! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 32.0.0
+//! DATE: 2024-02-20, STEPS: `50`, REPEAT: `20`, LOW RANGE: `[]`, HIGH RANGE: `[]`
 //! WORST CASE MAP SIZE: `1000000`
-//! HOSTNAME: `runner-r43aesjn-project-674-concurrent-0`, CPU: `Intel(R) Xeon(R) CPU @ 2.60GHz`
+//! HOSTNAME: `runner-bn-ce5rx-project-674-concurrent-0`, CPU: `Intel(R) Xeon(R) CPU @ 2.60GHz`
 //! WASM-EXECUTION: `Compiled`, CHAIN: `Some("asset-hub-rococo-dev")`, DB CACHE: 1024
 
 // Executed Command:
@@ -64,8 +64,8 @@ impl<T: frame_system::Config> pallet_xcm::WeightInfo for WeightInfo<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `145`
 		//  Estimated: `3610`
-		// Minimum execution time: 25_003_000 picoseconds.
-		Weight::from_parts(25_800_000, 0)
+		// Minimum execution time: 22_136_000 picoseconds.
+		Weight::from_parts(22_518_000, 0)
 			.saturating_add(Weight::from_parts(0, 3610))
 			.saturating_add(T::DbWeight::get().reads(6))
 			.saturating_add(T::DbWeight::get().writes(2))
@@ -90,8 +90,8 @@ impl<T: frame_system::Config> pallet_xcm::WeightInfo for WeightInfo<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `145`
 		//  Estimated: `3610`
-		// Minimum execution time: 88_832_000 picoseconds.
-		Weight::from_parts(90_491_000, 0)
+		// Minimum execution time: 92_277_000 picoseconds.
+		Weight::from_parts(94_843_000, 0)
 			.saturating_add(Weight::from_parts(0, 3610))
 			.saturating_add(T::DbWeight::get().reads(8))
 			.saturating_add(T::DbWeight::get().writes(3))
@@ -118,8 +118,8 @@ impl<T: frame_system::Config> pallet_xcm::WeightInfo for WeightInfo<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `400`
 		//  Estimated: `6196`
-		// Minimum execution time: 138_911_000 picoseconds.
-		Weight::from_parts(142_483_000, 0)
+		// Minimum execution time: 120_110_000 picoseconds.
+		Weight::from_parts(122_968_000, 0)
 			.saturating_add(Weight::from_parts(0, 6196))
 			.saturating_add(T::DbWeight::get().reads(9))
 			.saturating_add(T::DbWeight::get().writes(5))
@@ -148,8 +148,8 @@ impl<T: frame_system::Config> pallet_xcm::WeightInfo for WeightInfo<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `496`
 		//  Estimated: `6208`
-		// Minimum execution time: 146_932_000 picoseconds.
-		Weight::from_parts(153_200_000, 0)
+		// Minimum execution time: 143_116_000 picoseconds.
+		Weight::from_parts(147_355_000, 0)
 			.saturating_add(Weight::from_parts(0, 6208))
 			.saturating_add(T::DbWeight::get().reads(12))
 			.saturating_add(T::DbWeight::get().writes(7))
@@ -170,8 +170,8 @@ impl<T: frame_system::Config> pallet_xcm::WeightInfo for WeightInfo<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `0`
 		//  Estimated: `0`
-		// Minimum execution time: 7_081_000 picoseconds.
-		Weight::from_parts(7_397_000, 0)
+		// Minimum execution time: 6_517_000 picoseconds.
+		Weight::from_parts(6_756_000, 0)
 			.saturating_add(Weight::from_parts(0, 0))
 			.saturating_add(T::DbWeight::get().writes(1))
 	}
@@ -181,8 +181,8 @@ impl<T: frame_system::Config> pallet_xcm::WeightInfo for WeightInfo<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `0`
 		//  Estimated: `0`
-		// Minimum execution time: 2_007_000 picoseconds.
-		Weight::from_parts(2_183_000, 0)
+		// Minimum execution time: 1_894_000 picoseconds.
+		Weight::from_parts(2_024_000, 0)
 			.saturating_add(Weight::from_parts(0, 0))
 			.saturating_add(T::DbWeight::get().writes(1))
 	}
@@ -208,8 +208,8 @@ impl<T: frame_system::Config> pallet_xcm::WeightInfo for WeightInfo<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `145`
 		//  Estimated: `3610`
-		// Minimum execution time: 28_790_000 picoseconds.
-		Weight::from_parts(29_767_000, 0)
+		// Minimum execution time: 27_314_000 picoseconds.
+		Weight::from_parts(28_787_000, 0)
 			.saturating_add(Weight::from_parts(0, 3610))
 			.saturating_add(T::DbWeight::get().reads(8))
 			.saturating_add(T::DbWeight::get().writes(5))
@@ -234,8 +234,8 @@ impl<T: frame_system::Config> pallet_xcm::WeightInfo for WeightInfo<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `363`
 		//  Estimated: `3828`
-		// Minimum execution time: 30_951_000 picoseconds.
-		Weight::from_parts(31_804_000, 0)
+		// Minimum execution time: 29_840_000 picoseconds.
+		Weight::from_parts(30_589_000, 0)
 			.saturating_add(Weight::from_parts(0, 3828))
 			.saturating_add(T::DbWeight::get().reads(7))
 			.saturating_add(T::DbWeight::get().writes(4))
@@ -246,45 +246,45 @@ impl<T: frame_system::Config> pallet_xcm::WeightInfo for WeightInfo<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `0`
 		//  Estimated: `0`
-		// Minimum execution time: 2_164_000 picoseconds.
-		Weight::from_parts(2_311_000, 0)
+		// Minimum execution time: 1_893_000 picoseconds.
+		Weight::from_parts(2_017_000, 0)
 			.saturating_add(Weight::from_parts(0, 0))
 			.saturating_add(T::DbWeight::get().writes(1))
 	}
-	/// Storage: `PolkadotXcm::SupportedVersion` (r:4 w:2)
+	/// Storage: `PolkadotXcm::SupportedVersion` (r:5 w:2)
 	/// Proof: `PolkadotXcm::SupportedVersion` (`max_values`: None, `max_size`: None, mode: `Measured`)
 	fn migrate_supported_version() -> Weight {
 		// Proof Size summary in bytes:
-		//  Measured:  `162`
-		//  Estimated: `11052`
-		// Minimum execution time: 16_906_000 picoseconds.
-		Weight::from_parts(17_612_000, 0)
-			.saturating_add(Weight::from_parts(0, 11052))
-			.saturating_add(T::DbWeight::get().reads(4))
+		//  Measured:  `159`
+		//  Estimated: `13524`
+		// Minimum execution time: 19_211_000 picoseconds.
+		Weight::from_parts(19_552_000, 0)
+			.saturating_add(Weight::from_parts(0, 13524))
+			.saturating_add(T::DbWeight::get().reads(5))
 			.saturating_add(T::DbWeight::get().writes(2))
 	}
-	/// Storage: `PolkadotXcm::VersionNotifiers` (r:4 w:2)
+	/// Storage: `PolkadotXcm::VersionNotifiers` (r:5 w:2)
 	/// Proof: `PolkadotXcm::VersionNotifiers` (`max_values`: None, `max_size`: None, mode: `Measured`)
 	fn migrate_version_notifiers() -> Weight {
 		// Proof Size summary in bytes:
-		//  Measured:  `166`
-		//  Estimated: `11056`
-		// Minimum execution time: 17_443_000 picoseconds.
-		Weight::from_parts(18_032_000, 0)
-			.saturating_add(Weight::from_parts(0, 11056))
-			.saturating_add(T::DbWeight::get().reads(4))
+		//  Measured:  `163`
+		//  Estimated: `13528`
+		// Minimum execution time: 19_177_000 picoseconds.
+		Weight::from_parts(19_704_000, 0)
+			.saturating_add(Weight::from_parts(0, 13528))
+			.saturating_add(T::DbWeight::get().reads(5))
 			.saturating_add(T::DbWeight::get().writes(2))
 	}
-	/// Storage: `PolkadotXcm::VersionNotifyTargets` (r:5 w:0)
+	/// Storage: `PolkadotXcm::VersionNotifyTargets` (r:6 w:0)
 	/// Proof: `PolkadotXcm::VersionNotifyTargets` (`max_values`: None, `max_size`: None, mode: `Measured`)
 	fn already_notified_target() -> Weight {
 		// Proof Size summary in bytes:
 		//  Measured:  `173`
-		//  Estimated: `13538`
-		// Minimum execution time: 18_992_000 picoseconds.
-		Weight::from_parts(19_464_000, 0)
-			.saturating_add(Weight::from_parts(0, 13538))
-			.saturating_add(T::DbWeight::get().reads(5))
+		//  Estimated: `16013`
+		// Minimum execution time: 20_449_000 picoseconds.
+		Weight::from_parts(21_075_000, 0)
+			.saturating_add(Weight::from_parts(0, 16013))
+			.saturating_add(T::DbWeight::get().reads(6))
 	}
 	/// Storage: `PolkadotXcm::VersionNotifyTargets` (r:2 w:1)
 	/// Proof: `PolkadotXcm::VersionNotifyTargets` (`max_values`: None, `max_size`: None, mode: `Measured`)
@@ -304,36 +304,36 @@ impl<T: frame_system::Config> pallet_xcm::WeightInfo for WeightInfo<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `212`
 		//  Estimated: `6152`
-		// Minimum execution time: 28_011_000 picoseconds.
-		Weight::from_parts(28_716_000, 0)
+		// Minimum execution time: 26_578_000 picoseconds.
+		Weight::from_parts(27_545_000, 0)
 			.saturating_add(Weight::from_parts(0, 6152))
 			.saturating_add(T::DbWeight::get().reads(8))
 			.saturating_add(T::DbWeight::get().writes(3))
 	}
-	/// Storage: `PolkadotXcm::VersionNotifyTargets` (r:3 w:0)
+	/// Storage: `PolkadotXcm::VersionNotifyTargets` (r:4 w:0)
 	/// Proof: `PolkadotXcm::VersionNotifyTargets` (`max_values`: None, `max_size`: None, mode: `Measured`)
 	fn notify_target_migration_fail() -> Weight {
 		// Proof Size summary in bytes:
 		//  Measured:  `206`
-		//  Estimated: `8621`
-		// Minimum execution time: 9_533_000 picoseconds.
-		Weight::from_parts(9_856_000, 0)
-			.saturating_add(Weight::from_parts(0, 8621))
-			.saturating_add(T::DbWeight::get().reads(3))
+		//  Estimated: `11096`
+		// Minimum execution time: 11_646_000 picoseconds.
+		Weight::from_parts(11_944_000, 0)
+			.saturating_add(Weight::from_parts(0, 11096))
+			.saturating_add(T::DbWeight::get().reads(4))
 	}
-	/// Storage: `PolkadotXcm::VersionNotifyTargets` (r:4 w:2)
+	/// Storage: `PolkadotXcm::VersionNotifyTargets` (r:5 w:2)
 	/// Proof: `PolkadotXcm::VersionNotifyTargets` (`max_values`: None, `max_size`: None, mode: `Measured`)
 	fn migrate_version_notify_targets() -> Weight {
 		// Proof Size summary in bytes:
-		//  Measured:  `173`
-		//  Estimated: `11063`
-		// Minimum execution time: 17_628_000 picoseconds.
-		Weight::from_parts(18_146_000, 0)
-			.saturating_add(Weight::from_parts(0, 11063))
-			.saturating_add(T::DbWeight::get().reads(4))
+		//  Measured:  `170`
+		//  Estimated: `13535`
+		// Minimum execution time: 19_301_000 picoseconds.
+		Weight::from_parts(19_664_000, 0)
+			.saturating_add(Weight::from_parts(0, 13535))
+			.saturating_add(T::DbWeight::get().reads(5))
 			.saturating_add(T::DbWeight::get().writes(2))
 	}
-	/// Storage: `PolkadotXcm::VersionNotifyTargets` (r:4 w:2)
+	/// Storage: `PolkadotXcm::VersionNotifyTargets` (r:5 w:2)
 	/// Proof: `PolkadotXcm::VersionNotifyTargets` (`max_values`: None, `max_size`: None, mode: `Measured`)
 	/// Storage: `ParachainSystem::UpwardDeliveryFeeFactor` (r:1 w:0)
 	/// Proof: `ParachainSystem::UpwardDeliveryFeeFactor` (`max_values`: Some(1), `max_size`: None, mode: `Measured`)
@@ -349,12 +349,12 @@ impl<T: frame_system::Config> pallet_xcm::WeightInfo for WeightInfo<T> {
 	/// Proof: `ParachainSystem::PendingUpwardMessages` (`max_values`: Some(1), `max_size`: None, mode: `Measured`)
 	fn migrate_and_notify_old_targets() -> Weight {
 		// Proof Size summary in bytes:
-		//  Measured:  `215`
-		//  Estimated: `11105`
-		// Minimum execution time: 34_877_000 picoseconds.
-		Weight::from_parts(35_607_000, 0)
-			.saturating_add(Weight::from_parts(0, 11105))
-			.saturating_add(T::DbWeight::get().reads(10))
+		//  Measured:  `212`
+		//  Estimated: `13577`
+		// Minimum execution time: 35_715_000 picoseconds.
+		Weight::from_parts(36_915_000, 0)
+			.saturating_add(Weight::from_parts(0, 13577))
+			.saturating_add(T::DbWeight::get().reads(11))
 			.saturating_add(T::DbWeight::get().writes(4))
 	}
 	/// Storage: `PolkadotXcm::QueryCounter` (r:1 w:1)
@@ -365,8 +365,8 @@ impl<T: frame_system::Config> pallet_xcm::WeightInfo for WeightInfo<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `103`
 		//  Estimated: `1588`
-		// Minimum execution time: 5_370_000 picoseconds.
-		Weight::from_parts(5_616_000, 0)
+		// Minimum execution time: 4_871_000 picoseconds.
+		Weight::from_parts(5_066_000, 0)
 			.saturating_add(Weight::from_parts(0, 1588))
 			.saturating_add(T::DbWeight::get().reads(1))
 			.saturating_add(T::DbWeight::get().writes(2))
@@ -377,10 +377,22 @@ impl<T: frame_system::Config> pallet_xcm::WeightInfo for WeightInfo<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `7740`
 		//  Estimated: `11205`
-		// Minimum execution time: 26_820_000 picoseconds.
-		Weight::from_parts(27_143_000, 0)
+		// Minimum execution time: 25_150_000 picoseconds.
+		Weight::from_parts(26_119_000, 0)
 			.saturating_add(Weight::from_parts(0, 11205))
 			.saturating_add(T::DbWeight::get().reads(1))
 			.saturating_add(T::DbWeight::get().writes(1))
 	}
+	/// Storage: `PolkadotXcm::AssetTraps` (r:1 w:1)
+	/// Proof: `PolkadotXcm::AssetTraps` (`max_values`: None, `max_size`: None, mode: `Measured`)
+	fn claim_assets() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `160`
+		//  Estimated: `3625`
+		// Minimum execution time: 38_248_000 picoseconds.
+		Weight::from_parts(39_122_000, 0)
+			.saturating_add(Weight::from_parts(0, 3625))
+			.saturating_add(T::DbWeight::get().reads(1))
+			.saturating_add(T::DbWeight::get().writes(1))
+	}
 }

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

@@ -1511,6 +1511,13 @@ impl_runtime_apis! {
 					});
 					Some((assets, fee_index as u32, dest, verify))
 				}
+
+				fn get_asset() -> Asset {
+					Asset {
+						id: AssetId(Location::parent()),
+						fun: Fungible(ExistentialDeposit::get()),
+					}
+				}
 			}
 
 			use pallet_xcm_bridge_hub_router::benchmarking::{