XcmDryRunApi - Dry-running extrinsics to get their XCM effects

bridges/modules/xcm-bridge-hub-router/src/lib.rs

@@ -37,8 +37,9 @@ use codec::Encode;
 use frame_support::traits::Get;
 use sp_core::H256;
 use sp_runtime::{FixedPointNumber, FixedU128, Saturating};
+use sp_std::vec::Vec;
 use xcm::prelude::*;
-use xcm_builder::{ExporterFor, SovereignPaidRemoteExporter};
+use xcm_builder::{ExporterFor, InspectMessageQueues, SovereignPaidRemoteExporter};
 
 pub use pallet::*;
 pub use weights::WeightInfo;
@@ -95,7 +96,7 @@ pub mod pallet {
 		/// Origin of the sibling bridge hub that is allowed to report bridge status.
 		type BridgeHubOrigin: EnsureOrigin<Self::RuntimeOrigin>;
 		/// Actual message sender (`HRMP` or `DMP`) to the sibling bridge hub location.
-		type ToBridgeHubSender: SendXcm;
+		type ToBridgeHubSender: SendXcm + InspectMessageQueues;
 		/// Underlying channel with the sibling bridge hub. It must match the channel, used
 		/// by the `Self::ToBridgeHubSender`.
 		type WithBridgeHubChannel: XcmChannelStatusProvider;
@@ -396,6 +397,12 @@ impl<T: Config<I>, I: 'static> SendXcm for Pallet<T, I> {
 	}
 }
 
+impl<T: Config<I>, I: 'static> InspectMessageQueues for Pallet<T, I> {
+	fn get_messages() -> Vec<(VersionedLocation, Vec<VersionedXcm<()>>)> {
+		ViaBridgeHubExporter::<T, I>::get_messages()
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;
@@ -635,4 +642,36 @@ mod tests {
 			);
 		});
 	}
+
+	#[test]
+	fn get_messages_works() {
+		run_test(|| {
+			assert_ok!(send_xcm::<XcmBridgeHubRouter>(
+				(Parent, Parent, GlobalConsensus(BridgedNetworkId::get()), Parachain(1000)).into(),
+				vec![ClearOrigin].into()
+			));
+			assert_eq!(
+				XcmBridgeHubRouter::get_messages(),
+				vec![(
+					VersionedLocation::V4((Parent, Parachain(1002)).into()),
+					vec![VersionedXcm::V4(
+						Xcm::builder()
+							.withdraw_asset((Parent, 1_002_000))
+							.buy_execution((Parent, 1_002_000), Unlimited)
+							.set_appendix(
+								Xcm::builder_unsafe()
+									.deposit_asset(AllCounted(1), (Parent, Parachain(1000)))
+									.build()
+							)
+							.export_message(
+								Kusama,
+								Parachain(1000),
+								Xcm::builder_unsafe().clear_origin().build()
+							)
+							.build()
+					)],
+				),],
+			);
+		});
+	}
 }

bridges/modules/xcm-bridge-hub-router/src/mock.rs

@@ -19,14 +19,16 @@
 use crate as pallet_xcm_bridge_hub_router;
 
 use bp_xcm_bridge_hub_router::XcmChannelStatusProvider;
+use codec::Encode;
 use frame_support::{
 	construct_runtime, derive_impl, parameter_types,
 	traits::{Contains, Equals},
 };
 use frame_system::EnsureRoot;
 use sp_runtime::{traits::ConstU128, BuildStorage};
+use sp_std::cell::RefCell;
 use xcm::prelude::*;
-use xcm_builder::{NetworkExportTable, NetworkExportTableItem};
+use xcm_builder::{InspectMessageQueues, NetworkExportTable, NetworkExportTableItem};
 
 pub type AccountId = u64;
 type Block = frame_system::mocking::MockBlock<TestRuntime>;
@@ -106,19 +108,43 @@ impl TestToBridgeHubSender {
 	}
 }
 
+thread_local! {
+	pub static SENT_XCM: RefCell<Vec<(Location, Xcm<()>)>> = RefCell::new(Vec::new());
+}
+
 impl SendXcm for TestToBridgeHubSender {
-	type Ticket = ();
+	type Ticket = (Location, Xcm<()>);
 
 	fn validate(
-		_destination: &mut Option<Location>,
-		_message: &mut Option<Xcm<()>>,
+		destination: &mut Option<Location>,
+		message: &mut Option<Xcm<()>>,
 	) -> SendResult<Self::Ticket> {
-		Ok(((), (BridgeFeeAsset::get(), HRMP_FEE).into()))
+		let pair = (destination.take().unwrap(), message.take().unwrap());
+		Ok((pair, (BridgeFeeAsset::get(), HRMP_FEE).into()))
 	}
 
-	fn deliver(_ticket: Self::Ticket) -> Result<XcmHash, SendError> {
+	fn deliver(pair: Self::Ticket) -> Result<XcmHash, SendError> {
 		frame_support::storage::unhashed::put(b"TestToBridgeHubSender.Sent", &true);
-		Ok([0u8; 32])
+		let hash = fake_message_hash(&pair.1);
+		SENT_XCM.with(|q| q.borrow_mut().push(pair));
+		Ok(hash)
+	}
+}
+
+impl InspectMessageQueues for TestToBridgeHubSender {
+	fn get_messages() -> Vec<(VersionedLocation, Vec<VersionedXcm<()>>)> {
+		SENT_XCM.with(|q| {
+			(*q.borrow())
+				.clone()
+				.iter()
+				.map(|(location, message)| {
+					(
+						VersionedLocation::V4(location.clone()),
+						vec![VersionedXcm::V4(message.clone())],
+					)
+				})
+				.collect()
+		})
 	}
 }
 
@@ -146,3 +172,7 @@ pub fn new_test_ext() -> sp_io::TestExternalities {
 pub fn run_test<T>(test: impl FnOnce() -> T) -> T {
 	new_test_ext().execute_with(test)
 }
+
+pub(crate) fn fake_message_hash<T>(message: &Xcm<T>) -> XcmHash {
+	message.using_encoded(sp_io::hashing::blake2_256)
+}

cumulus/pallets/parachain-system/Cargo.toml

@@ -38,6 +38,7 @@ polkadot-parachain-primitives = { path = "../../../polkadot/parachain", default-
 polkadot-runtime-parachains = { path = "../../../polkadot/runtime/parachains", default-features = false }
 polkadot-runtime-common = { path = "../../../polkadot/runtime/common", default-features = false, optional = true }
 xcm = { package = "staging-xcm", path = "../../../polkadot/xcm", default-features = false }
+xcm-builder = { package = "staging-xcm-builder", path = "../../../polkadot/xcm/xcm-builder", default-features = false }
 
 # Cumulus
 cumulus-pallet-parachain-system-proc-macro = { path = "proc-macro", default-features = false }
@@ -95,6 +96,7 @@ std = [
 	"sp-tracing/std",
 	"sp-trie/std",
 	"trie-db/std",
+	"xcm-builder/std",
 	"xcm/std",
 ]
 
@@ -109,6 +111,7 @@ runtime-benchmarks = [
 	"polkadot-runtime-common/runtime-benchmarks",
 	"polkadot-runtime-parachains/runtime-benchmarks",
 	"sp-runtime/runtime-benchmarks",
+	"xcm-builder/runtime-benchmarks",
 ]
 
 try-runtime = [

cumulus/pallets/parachain-system/src/lib.rs

@@ -55,7 +55,8 @@ use sp_runtime::{
 	BoundedSlice, FixedU128, RuntimeDebug, Saturating,
 };
 use sp_std::{cmp, collections::btree_map::BTreeMap, prelude::*};
-use xcm::latest::XcmHash;
+use xcm::{latest::XcmHash, VersionedLocation, VersionedXcm};
+use xcm_builder::InspectMessageQueues;
 
 mod benchmarking;
 pub mod migration;
@@ -1608,6 +1609,19 @@ impl<T: Config> UpwardMessageSender for Pallet<T> {
 	}
 }
 
+impl<T: Config> InspectMessageQueues for Pallet<T> {
+	fn get_messages() -> Vec<(VersionedLocation, Vec<VersionedXcm<()>>)> {
+		use xcm::prelude::*;
+
+		let messages: Vec<VersionedXcm<()>> = PendingUpwardMessages::<T>::get()
+			.iter()
+			.map(|encoded_message| VersionedXcm::<()>::decode(&mut &encoded_message[..]).unwrap())
+			.collect();
+
+		vec![(VersionedLocation::V4(Parent.into()), messages)]
+	}
+}
+
 #[cfg(feature = "runtime-benchmarks")]
 impl<T: Config> polkadot_runtime_common::xcm_sender::EnsureForParachain for Pallet<T> {
 	fn ensure(para_id: ParaId) {

cumulus/pallets/xcmp-queue/Cargo.toml

@@ -28,6 +28,7 @@ polkadot-runtime-common = { path = "../../../polkadot/runtime/common", default-f
 polkadot-runtime-parachains = { path = "../../../polkadot/runtime/parachains", default-features = false }
 xcm = { package = "staging-xcm", path = "../../../polkadot/xcm", default-features = false }
 xcm-executor = { package = "staging-xcm-executor", path = "../../../polkadot/xcm/xcm-executor", default-features = false }
+xcm-builder = { package = "staging-xcm-builder", path = "../../../polkadot/xcm/xcm-builder", default-features = false }
 
 # Cumulus
 cumulus-primitives-core = { path = "../../primitives/core", default-features = false }
@@ -46,9 +47,6 @@ sp-core = { path = "../../../substrate/primitives/core" }
 pallet-balances = { path = "../../../substrate/frame/balances" }
 frame-support = { path = "../../../substrate/frame/support", features = ["experimental"] }
 
-# Polkadot
-xcm-builder = { package = "staging-xcm-builder", path = "../../../polkadot/xcm/xcm-builder" }
-
 # Cumulus
 cumulus-pallet-parachain-system = { path = "../parachain-system", features = ["parameterized-consensus-hook"] }
 
@@ -71,6 +69,7 @@ std = [
 	"sp-io/std",
 	"sp-runtime/std",
 	"sp-std/std",
+	"xcm-builder/std",
 	"xcm-executor/std",
 	"xcm/std",
 ]

cumulus/pallets/xcmp-queue/src/lib.rs

@@ -70,7 +70,8 @@ use scale_info::TypeInfo;
 use sp_core::MAX_POSSIBLE_ALLOCATION;
 use sp_runtime::{FixedU128, RuntimeDebug, Saturating};
 use sp_std::prelude::*;
-use xcm::{latest::prelude::*, VersionedXcm, WrapVersion, MAX_XCM_DECODE_DEPTH};
+use xcm::{latest::prelude::*, VersionedLocation, VersionedXcm, WrapVersion, MAX_XCM_DECODE_DEPTH};
+use xcm_builder::InspectMessageQueues;
 use xcm_executor::traits::ConvertOrigin;
 
 pub use pallet::*;
@@ -947,6 +948,38 @@ impl<T: Config> SendXcm for Pallet<T> {
 	}
 }
 
+impl<T: Config> InspectMessageQueues for Pallet<T> {
+	fn get_messages() -> Vec<(VersionedLocation, Vec<VersionedXcm<()>>)> {
+		use xcm::prelude::*;
+
+		OutboundXcmpMessages::<T>::iter()
+			.map(|(para_id, _, messages)| {
+				let mut data = &messages[..];
+				let decoded_format =
+					XcmpMessageFormat::decode_with_depth_limit(MAX_XCM_DECODE_DEPTH, &mut data)
+						.unwrap();
+				if decoded_format != XcmpMessageFormat::ConcatenatedVersionedXcm {
+					panic!("Unexpected format.")
+				}
+				let mut decoded_messages = Vec::new();
+				while !data.is_empty() {
+					let decoded_message = VersionedXcm::<()>::decode_with_depth_limit(
+						MAX_XCM_DECODE_DEPTH,
+						&mut data,
+					)
+					.unwrap();
+					decoded_messages.push(decoded_message);
+				}
+
+				(
+					VersionedLocation::V4((Parent, Parachain(para_id.into())).into()),
+					decoded_messages,
+				)
+			})
+			.collect()
+	}
+}
+
 impl<T: Config> FeeTracker for Pallet<T> {
 	type Id = ParaId;
 

cumulus/pallets/xcmp-queue/src/mock.rs

@@ -178,6 +178,7 @@ impl xcm_executor::Config for XcmConfig {
 	type HrmpNewChannelOpenRequestHandler = ();
 	type HrmpChannelAcceptedHandler = ();
 	type HrmpChannelClosingHandler = ();
+	type XcmRecorder = ();
 }
 
 pub type XcmRouter = (