use transaction tracker in messages relay (#1581)

bridges/relays/client-substrate/src/lib.rs

@@ -88,30 +88,3 @@ pub fn transaction_stall_timeout(
 		.map(|mortality_period| average_block_interval.saturating_mul(mortality_period + 1 + 1))
 		.unwrap_or(default_stall_timeout)
 }
-
-/// Returns stall timeout for relay loop that submit transactions to two chains.
-///
-/// Bidirectional relay may have two active transactions. Even if one of them has been spoiled, we
-/// can't just restart the loop - the other transaction may still be alive and we'll be submitting
-/// duplicate transaction, which may result in funds loss. So we'll be selecting maximal mortality
-/// for choosing loop stall timeout.
-pub fn bidirectional_transaction_stall_timeout(
-	left_mortality_period: Option<u32>,
-	right_mortality_period: Option<u32>,
-	left_average_block_interval: Duration,
-	right_average_block_interval: Duration,
-	default_stall_timeout: Duration,
-) -> Duration {
-	std::cmp::max(
-		transaction_stall_timeout(
-			left_mortality_period,
-			left_average_block_interval,
-			default_stall_timeout,
-		),
-		transaction_stall_timeout(
-			right_mortality_period,
-			right_average_block_interval,
-			default_stall_timeout,
-		),
-	)
-}

bridges/relays/lib-substrate-relay/src/messages_lane.rs

@@ -164,13 +164,6 @@ where
 {
 	let source_client = params.source_client;
 	let target_client = params.target_client;
-	let stall_timeout = relay_substrate_client::bidirectional_transaction_stall_timeout(
-		params.source_transaction_params.mortality,
-		params.target_transaction_params.mortality,
-		P::SourceChain::AVERAGE_BLOCK_INTERVAL,
-		P::TargetChain::AVERAGE_BLOCK_INTERVAL,
-		STALL_TIMEOUT,
-	);
 	let relayer_id_at_source: AccountIdOf<P::SourceChain> =
 		params.source_transaction_params.signer.public().into();
 
@@ -202,8 +195,7 @@ where
 			Max messages in single transaction: {}\n\t\
 			Max messages size in single transaction: {}\n\t\
 			Max messages weight in single transaction: {}\n\t\
-			Tx mortality: {:?} (~{}m)/{:?} (~{}m)\n\t\
-			Stall timeout: {:?}",
+			Tx mortality: {:?} (~{}m)/{:?} (~{}m)",
 		P::SourceChain::NAME,
 		P::TargetChain::NAME,
 		P::SourceChain::NAME,
@@ -223,7 +215,6 @@ where
 			P::TargetChain::AVERAGE_BLOCK_INTERVAL,
 			STALL_TIMEOUT,
 		).as_secs_f64() / 60.0f64,
-		stall_timeout,
 	);
 
 	messages_relay::message_lane_loop::run(
@@ -232,7 +223,6 @@ where
 			source_tick: P::SourceChain::AVERAGE_BLOCK_INTERVAL,
 			target_tick: P::TargetChain::AVERAGE_BLOCK_INTERVAL,
 			reconnect_delay: relay_utils::relay_loop::RECONNECT_DELAY,
-			stall_timeout,
 			delivery_params: messages_relay::message_lane_loop::MessageDeliveryParams {
 				max_unrewarded_relayer_entries_at_target:
 					P::SourceChain::MAX_UNREWARDED_RELAYERS_IN_CONFIRMATION_TX,

bridges/relays/lib-substrate-relay/src/messages_source.rs

@@ -51,7 +51,7 @@ use num_traits::{Bounded, Zero};
 use relay_substrate_client::{
 	AccountIdOf, AccountKeyPairOf, BalanceOf, BlockNumberOf, Chain, ChainWithMessages, Client,
 	Error as SubstrateError, HashOf, HeaderIdOf, IndexOf, SignParam, TransactionEra,
-	TransactionSignScheme, UnsignedTransaction,
+	TransactionSignScheme, TransactionTracker, UnsignedTransaction,
 };
 use relay_utils::{relay_loop::Client as RelayClient, HeaderId};
 use sp_core::{Bytes, Pair};
@@ -144,6 +144,8 @@ where
 		From<<AccountKeyPairOf<P::SourceTransactionSignScheme> as Pair>::Public>,
 	P::SourceTransactionSignScheme: TransactionSignScheme<Chain = P::SourceChain>,
 {
+	type TransactionTracker = TransactionTracker<P::SourceChain>;
+
 	async fn state(&self) -> Result<SourceClientState<MessageLaneAdapter<P>>, SubstrateError> {
 		// we can't continue to deliver confirmations if source node is out of sync, because
 		// it may have already received confirmations that we're going to deliver
@@ -338,13 +340,13 @@ where
 		&self,
 		_generated_at_block: TargetHeaderIdOf<MessageLaneAdapter<P>>,
 		proof: <MessageLaneAdapter<P> as MessageLane>::MessagesReceivingProof,
-	) -> Result<(), SubstrateError> {
+	) -> Result<Self::TransactionTracker, SubstrateError> {
 		let genesis_hash = *self.source_client.genesis_hash();
 		let transaction_params = self.transaction_params.clone();
 		let (spec_version, transaction_version) =
 			self.source_client.simple_runtime_version().await?;
 		self.source_client
-			.submit_signed_extrinsic(
+			.submit_and_watch_signed_extrinsic(
 				self.transaction_params.signer.public().into(),
 				SignParam::<P::SourceTransactionSignScheme> {
 					spec_version,
@@ -362,8 +364,7 @@ where
 					)
 				},
 			)
-			.await?;
-		Ok(())
+			.await
 	}
 
 	async fn require_target_header_on_source(&self, id: TargetHeaderIdOf<MessageLaneAdapter<P>>) {

bridges/relays/lib-substrate-relay/src/messages_target.rs

@@ -39,13 +39,13 @@ use codec::Encode;
 use frame_support::weights::{Weight, WeightToFee};
 use messages_relay::{
 	message_lane::{MessageLane, SourceHeaderIdOf, TargetHeaderIdOf},
-	message_lane_loop::{TargetClient, TargetClientState},
+	message_lane_loop::{NoncesSubmitArtifacts, TargetClient, TargetClientState},
 };
 use num_traits::{Bounded, Zero};
 use relay_substrate_client::{
 	AccountIdOf, AccountKeyPairOf, BalanceOf, BlockNumberOf, Chain, ChainWithMessages, Client,
 	Error as SubstrateError, HashOf, HeaderIdOf, IndexOf, SignParam, TransactionEra,
-	TransactionSignScheme, UnsignedTransaction, WeightToFeeOf,
+	TransactionSignScheme, TransactionTracker, UnsignedTransaction, WeightToFeeOf,
 };
 use relay_utils::{relay_loop::Client as RelayClient, HeaderId};
 use sp_core::{Bytes, Pair};
@@ -145,6 +145,8 @@ where
 	P::TargetTransactionSignScheme: TransactionSignScheme<Chain = P::TargetChain>,
 	BalanceOf<P::SourceChain>: TryFrom<BalanceOf<P::TargetChain>>,
 {
+	type TransactionTracker = TransactionTracker<P::TargetChain>;
+
 	async fn state(&self) -> Result<TargetClientState<MessageLaneAdapter<P>>, SubstrateError> {
 		// we can't continue to deliver confirmations if source node is out of sync, because
 		// it may have already received confirmations that we're going to deliver
@@ -245,15 +247,16 @@ where
 		_generated_at_header: SourceHeaderIdOf<MessageLaneAdapter<P>>,
 		nonces: RangeInclusive<MessageNonce>,
 		proof: <MessageLaneAdapter<P> as MessageLane>::MessagesProof,
-	) -> Result<RangeInclusive<MessageNonce>, SubstrateError> {
+	) -> Result<NoncesSubmitArtifacts<Self::TransactionTracker>, SubstrateError> {
 		let genesis_hash = *self.target_client.genesis_hash();
 		let transaction_params = self.transaction_params.clone();
 		let relayer_id_at_source = self.relayer_id_at_source.clone();
 		let nonces_clone = nonces.clone();
 		let (spec_version, transaction_version) =
 			self.target_client.simple_runtime_version().await?;
-		self.target_client
-			.submit_signed_extrinsic(
+		let tx_tracker = self
+			.target_client
+			.submit_and_watch_signed_extrinsic(
 				self.transaction_params.signer.public().into(),
 				SignParam::<P::TargetTransactionSignScheme> {
 					spec_version,
@@ -274,7 +277,7 @@ where
 				},
 			)
 			.await?;
-		Ok(nonces)
+		Ok(NoncesSubmitArtifacts { nonces, tx_tracker })
 	}
 
 	async fn require_source_header_on_target(&self, id: SourceHeaderIdOf<MessageLaneAdapter<P>>) {

bridges/relays/messages/src/message_lane_loop.rs

@@ -33,7 +33,7 @@ use bp_messages::{LaneId, MessageNonce, UnrewardedRelayersState, Weight};
 use bp_runtime::messages::DispatchFeePayment;
 use relay_utils::{
 	interval, metrics::MetricsParams, process_future_result, relay_loop::Client as RelayClient,
-	retry_backoff, FailedClient,
+	retry_backoff, FailedClient, TransactionTracker,
 };
 
 use crate::{
@@ -55,8 +55,6 @@ pub struct Params<Strategy: RelayStrategy> {
 	pub target_tick: Duration,
 	/// Delay between moments when connection error happens and our reconnect attempt.
 	pub reconnect_delay: Duration,
-	/// The loop will auto-restart if there has been no updates during this period.
-	pub stall_timeout: Duration,
 	/// Message delivery race parameters.
 	pub delivery_params: MessageDeliveryParams<Strategy>,
 }
@@ -119,9 +117,20 @@ pub struct MessageProofParameters {
 	pub dispatch_weight: Weight,
 }
 
+/// Artifacts of submitting nonces proof.
+pub struct NoncesSubmitArtifacts<T> {
+	/// Submitted nonces range.
+	pub nonces: RangeInclusive<MessageNonce>,
+	/// Submitted transaction tracker.
+	pub tx_tracker: T,
+}
+
 /// Source client trait.
 #[async_trait]
 pub trait SourceClient<P: MessageLane>: RelayClient {
+	/// Transaction tracker to track submitted transactions.
+	type TransactionTracker: TransactionTracker;
+
 	/// Returns state of the client.
 	async fn state(&self) -> Result<SourceClientState<P>, Self::Error>;
 
@@ -160,7 +169,7 @@ pub trait SourceClient<P: MessageLane>: RelayClient {
 		&self,
 		generated_at_block: TargetHeaderIdOf<P>,
 		proof: P::MessagesReceivingProof,
-	) -> Result<(), Self::Error>;
+	) -> Result<Self::TransactionTracker, Self::Error>;
 
 	/// We need given finalized target header on source to continue synchronization.
 	async fn require_target_header_on_source(&self, id: TargetHeaderIdOf<P>);
@@ -172,6 +181,9 @@ pub trait SourceClient<P: MessageLane>: RelayClient {
 /// Target client trait.
 #[async_trait]
 pub trait TargetClient<P: MessageLane>: RelayClient {
+	/// Transaction tracker to track submitted transactions.
+	type TransactionTracker: TransactionTracker;
+
 	/// Returns state of the client.
 	async fn state(&self) -> Result<TargetClientState<P>, Self::Error>;
 
@@ -205,7 +217,7 @@ pub trait TargetClient<P: MessageLane>: RelayClient {
 		generated_at_header: SourceHeaderIdOf<P>,
 		nonces: RangeInclusive<MessageNonce>,
 		proof: P::MessagesProof,
-	) -> Result<RangeInclusive<MessageNonce>, Self::Error>;
+	) -> Result<NoncesSubmitArtifacts<Self::TransactionTracker>, Self::Error>;
 
 	/// We need given finalized source header on target to continue synchronization.
 	async fn require_source_header_on_target(&self, id: SourceHeaderIdOf<P>);
@@ -327,7 +339,6 @@ async fn run_until_connection_lost<
 		delivery_source_state_receiver,
 		target_client.clone(),
 		delivery_target_state_receiver,
-		params.stall_timeout,
 		metrics_msg.clone(),
 		params.delivery_params,
 	)
@@ -342,7 +353,6 @@ async fn run_until_connection_lost<
 		receiving_source_state_receiver,
 		target_client.clone(),
 		receiving_target_state_receiver,
-		params.stall_timeout,
 		metrics_msg.clone(),
 	)
 	.fuse();
@@ -465,7 +475,7 @@ pub(crate) mod tests {
 	use futures::stream::StreamExt;
 	use parking_lot::Mutex;
 
-	use relay_utils::{HeaderId, MaybeConnectionError};
+	use relay_utils::{HeaderId, MaybeConnectionError, TrackedTransactionStatus};
 
 	use crate::relay_strategy::AltruisticStrategy;
 
@@ -518,19 +528,37 @@ pub(crate) mod tests {
 		type TargetHeaderHash = TestTargetHeaderHash;
 	}
 
-	#[derive(Debug, Default, Clone)]
+	#[derive(Clone, Debug)]
+	pub struct TestTransactionTracker(TrackedTransactionStatus);
+
+	impl Default for TestTransactionTracker {
+		fn default() -> TestTransactionTracker {
+			TestTransactionTracker(TrackedTransactionStatus::Finalized)
+		}
+	}
+
+	#[async_trait]
+	impl TransactionTracker for TestTransactionTracker {
+		async fn wait(self) -> TrackedTransactionStatus {
+			self.0
+		}
+	}
+
+	#[derive(Debug, Clone)]
 	pub struct TestClientData {
 		is_source_fails: bool,
 		is_source_reconnected: bool,
 		source_state: SourceClientState<TestMessageLane>,
 		source_latest_generated_nonce: MessageNonce,
 		source_latest_confirmed_received_nonce: MessageNonce,
+		source_tracked_transaction_status: TrackedTransactionStatus,
 		submitted_messages_receiving_proofs: Vec<TestMessagesReceivingProof>,
 		is_target_fails: bool,
 		is_target_reconnected: bool,
 		target_state: SourceClientState<TestMessageLane>,
 		target_latest_received_nonce: MessageNonce,
 		target_latest_confirmed_received_nonce: MessageNonce,
+		target_tracked_transaction_status: TrackedTransactionStatus,
 		submitted_messages_proofs: Vec<TestMessagesProof>,
 		target_to_source_header_required: Option<TestTargetHeaderId>,
 		target_to_source_header_requirements: Vec<TestTargetHeaderId>,
@@ -538,6 +566,31 @@ pub(crate) mod tests {
 		source_to_target_header_requirements: Vec<TestSourceHeaderId>,
 	}
 
+	impl Default for TestClientData {
+		fn default() -> TestClientData {
+			TestClientData {
+				is_source_fails: false,
+				is_source_reconnected: false,
+				source_state: Default::default(),
+				source_latest_generated_nonce: 0,
+				source_latest_confirmed_received_nonce: 0,
+				source_tracked_transaction_status: TrackedTransactionStatus::Finalized,
+				submitted_messages_receiving_proofs: Vec::new(),
+				is_target_fails: false,
+				is_target_reconnected: false,
+				target_state: Default::default(),
+				target_latest_received_nonce: 0,
+				target_latest_confirmed_received_nonce: 0,
+				target_tracked_transaction_status: TrackedTransactionStatus::Finalized,
+				submitted_messages_proofs: Vec::new(),
+				target_to_source_header_required: None,
+				target_to_source_header_requirements: Vec::new(),
+				source_to_target_header_required: None,
+				source_to_target_header_requirements: Vec::new(),
+			}
+		}
+	}
+
 	#[derive(Clone)]
 	pub struct TestSourceClient {
 		data: Arc<Mutex<TestClientData>>,
@@ -569,6 +622,8 @@ pub(crate) mod tests {
 
 	#[async_trait]
 	impl SourceClient<TestMessageLane> for TestSourceClient {
+		type TransactionTracker = TestTransactionTracker;
+
 		async fn state(&self) -> Result<SourceClientState<TestMessageLane>, TestError> {
 			let mut data = self.data.lock();
 			(self.tick)(&mut data);
@@ -648,7 +703,7 @@ pub(crate) mod tests {
 			&self,
 			_generated_at_block: TargetHeaderIdOf<TestMessageLane>,
 			proof: TestMessagesReceivingProof,
-		) -> Result<(), TestError> {
+		) -> Result<Self::TransactionTracker, TestError> {
 			let mut data = self.data.lock();
 			(self.tick)(&mut data);
 			data.source_state.best_self =
@@ -656,7 +711,7 @@ pub(crate) mod tests {
 			data.source_state.best_finalized_self = data.source_state.best_self;
 			data.submitted_messages_receiving_proofs.push(proof);
 			data.source_latest_confirmed_received_nonce = proof;
-			Ok(())
+			Ok(TestTransactionTracker(data.source_tracked_transaction_status))
 		}
 
 		async fn require_target_header_on_source(&self, id: TargetHeaderIdOf<TestMessageLane>) {
@@ -702,6 +757,8 @@ pub(crate) mod tests {
 
 	#[async_trait]
 	impl TargetClient<TestMessageLane> for TestTargetClient {
+		type TransactionTracker = TestTransactionTracker;
+
 		async fn state(&self) -> Result<TargetClientState<TestMessageLane>, TestError> {
 			let mut data = self.data.lock();
 			(self.tick)(&mut data);
@@ -762,7 +819,7 @@ pub(crate) mod tests {
 			_generated_at_header: SourceHeaderIdOf<TestMessageLane>,
 			nonces: RangeInclusive<MessageNonce>,
 			proof: TestMessagesProof,
-		) -> Result<RangeInclusive<MessageNonce>, TestError> {
+		) -> Result<NoncesSubmitArtifacts<Self::TransactionTracker>, TestError> {
 			let mut data = self.data.lock();
 			(self.tick)(&mut data);
 			if data.is_target_fails {
@@ -777,7 +834,10 @@ pub(crate) mod tests {
 					target_latest_confirmed_received_nonce;
 			}
 			data.submitted_messages_proofs.push(proof);
-			Ok(nonces)
+			Ok(NoncesSubmitArtifacts {
+				nonces,
+				tx_tracker: TestTransactionTracker(data.target_tracked_transaction_status),
+			})
 		}
 
 		async fn require_source_header_on_target(&self, id: SourceHeaderIdOf<TestMessageLane>) {
@@ -817,7 +877,6 @@ pub(crate) mod tests {
 					source_tick: Duration::from_millis(100),
 					target_tick: Duration::from_millis(100),
 					reconnect_delay: Duration::from_millis(0),
-					stall_timeout: Duration::from_millis(60 * 1000),
 					delivery_params: MessageDeliveryParams {
 						max_unrewarded_relayer_entries_at_target: 4,
 						max_unconfirmed_nonces_at_target: 4,
@@ -889,6 +948,54 @@ pub(crate) mod tests {
 		assert_eq!(result.submitted_messages_proofs, vec![(1..=1, None)],);
 	}
 
+	#[test]
+	fn message_lane_loop_is_able_to_recover_from_race_stall() {
+		// with this configuration, both source and target clients will lose their transactions =>
+		// reconnect will happen
+		let (source_exit_sender, exit_receiver) = unbounded();
+		let target_exit_sender = source_exit_sender.clone();
+		let result = run_loop_test(
+			TestClientData {
+				source_state: ClientState {
+					best_self: HeaderId(0, 0),
+					best_finalized_self: HeaderId(0, 0),
+					best_finalized_peer_at_best_self: HeaderId(0, 0),
+					actual_best_finalized_peer_at_best_self: HeaderId(0, 0),
+				},
+				source_latest_generated_nonce: 1,
+				source_tracked_transaction_status: TrackedTransactionStatus::Lost,
+				target_state: ClientState {
+					best_self: HeaderId(0, 0),
+					best_finalized_self: HeaderId(0, 0),
+					best_finalized_peer_at_best_self: HeaderId(0, 0),
+					actual_best_finalized_peer_at_best_self: HeaderId(0, 0),
+				},
+				target_latest_received_nonce: 0,
+				target_tracked_transaction_status: TrackedTransactionStatus::Lost,
+				..Default::default()
+			},
+			Arc::new(move |data: &mut TestClientData| {
+				if data.is_source_reconnected {
+					data.source_tracked_transaction_status = TrackedTransactionStatus::Finalized;
+				}
+				if data.is_source_reconnected && data.is_target_reconnected {
+					source_exit_sender.unbounded_send(()).unwrap();
+				}
+			}),
+			Arc::new(move |data: &mut TestClientData| {
+				if data.is_target_reconnected {
+					data.target_tracked_transaction_status = TrackedTransactionStatus::Finalized;
+				}
+				if data.is_source_reconnected && data.is_target_reconnected {
+					target_exit_sender.unbounded_send(()).unwrap();
+				}
+			}),
+			exit_receiver.into_future().map(|(_, _)| ()),
+		);
+
+		assert!(result.is_source_reconnected);
+	}
+
 	#[test]
 	fn message_lane_loop_works() {
 		let (exit_sender, exit_receiver) = unbounded();

bridges/relays/messages/src/message_race_delivery.rs

@@ -13,7 +13,7 @@
 
 //! Message delivery race delivers proof-of-messages from "lane.source" to "lane.target".
 
-use std::{collections::VecDeque, marker::PhantomData, ops::RangeInclusive, time::Duration};
+use std::{collections::VecDeque, marker::PhantomData, ops::RangeInclusive};
 
 use async_trait::async_trait;
 use futures::stream::FusedStream;
@@ -24,7 +24,7 @@ use relay_utils::FailedClient;
 use crate::{
 	message_lane::{MessageLane, SourceHeaderIdOf, TargetHeaderIdOf},
 	message_lane_loop::{
-		MessageDeliveryParams, MessageDetailsMap, MessageProofParameters,
+		MessageDeliveryParams, MessageDetailsMap, MessageProofParameters, NoncesSubmitArtifacts,
 		SourceClient as MessageLaneSourceClient, SourceClientState,
 		TargetClient as MessageLaneTargetClient, TargetClientState,
 	},
@@ -43,7 +43,6 @@ pub async fn run<P: MessageLane, Strategy: RelayStrategy>(
 	source_state_updates: impl FusedStream<Item = SourceClientState<P>>,
 	target_client: impl MessageLaneTargetClient<P>,
 	target_state_updates: impl FusedStream<Item = TargetClientState<P>>,
-	stall_timeout: Duration,
 	metrics_msg: Option<MessageLaneLoopMetrics>,
 	params: MessageDeliveryParams<Strategy>,
 ) -> Result<(), FailedClient> {
@@ -60,7 +59,6 @@ pub async fn run<P: MessageLane, Strategy: RelayStrategy>(
 			_phantom: Default::default(),
 		},
 		target_state_updates,
-		stall_timeout,
 		MessageDeliveryStrategy::<P, Strategy, _, _> {
 			lane_source_client: source_client,
 			lane_target_client: target_client,
@@ -174,6 +172,7 @@ where
 {
 	type Error = C::Error;
 	type TargetNoncesData = DeliveryRaceTargetNoncesData;
+	type TransactionTracker = C::TransactionTracker;
 
 	async fn require_source_header(&self, id: SourceHeaderIdOf<P>) {
 		self.client.require_source_header_on_target(id).await
@@ -215,7 +214,7 @@ where
 		generated_at_block: SourceHeaderIdOf<P>,
 		nonces: RangeInclusive<MessageNonce>,
 		proof: P::MessagesProof,
-	) -> Result<RangeInclusive<MessageNonce>, Self::Error> {
+	) -> Result<NoncesSubmitArtifacts<Self::TransactionTracker>, Self::Error> {
 		self.client.submit_messages_proof(generated_at_block, nonces, proof).await
 	}
 }

bridges/relays/messages/src/message_race_loop.rs

@@ -20,7 +20,7 @@
 //! associated data - like messages, lane state, etc) to the target node by
 //! generating and submitting proof.
 
-use crate::message_lane_loop::ClientState;
+use crate::message_lane_loop::{ClientState, NoncesSubmitArtifacts};
 
 use async_trait::async_trait;
 use bp_messages::MessageNonce;
@@ -28,7 +28,10 @@ use futures::{
 	future::FutureExt,
 	stream::{FusedStream, StreamExt},
 };
-use relay_utils::{process_future_result, retry_backoff, FailedClient, MaybeConnectionError};
+use relay_utils::{
+	process_future_result, retry_backoff, FailedClient, MaybeConnectionError,
+	TrackedTransactionStatus, TransactionTracker,
+};
 use std::{
 	fmt::Debug,
 	ops::RangeInclusive,
@@ -124,6 +127,8 @@ pub trait TargetClient<P: MessageRace> {
 	type Error: std::fmt::Debug + MaybeConnectionError;
 	/// Type of the additional data from the target client, used by the race.
 	type TargetNoncesData: std::fmt::Debug;
+	/// Transaction tracker to track submitted transactions.
+	type TransactionTracker: TransactionTracker;
 
 	/// Ask headers relay to relay finalized headers up to (and including) given header
 	/// from race source to race target.
@@ -141,7 +146,7 @@ pub trait TargetClient<P: MessageRace> {
 		generated_at_block: P::SourceHeaderId,
 		nonces: RangeInclusive<MessageNonce>,
 		proof: P::Proof,
-	) -> Result<RangeInclusive<MessageNonce>, Self::Error>;
+	) -> Result<NoncesSubmitArtifacts<Self::TransactionTracker>, Self::Error>;
 }
 
 /// Race strategy.
@@ -222,7 +227,6 @@ pub async fn run<P: MessageRace, SC: SourceClient<P>, TC: TargetClient<P>>(
 	race_source_updated: impl FusedStream<Item = SourceClientState<P>>,
 	race_target: TC,
 	race_target_updated: impl FusedStream<Item = TargetClientState<P>>,
-	stall_timeout: Duration,
 	mut strategy: impl RaceStrategy<
 		P::SourceHeaderId,
 		P::TargetHeaderId,
@@ -234,7 +238,6 @@ pub async fn run<P: MessageRace, SC: SourceClient<P>, TC: TargetClient<P>>(
 ) -> Result<(), FailedClient> {
 	let mut progress_context = Instant::now();
 	let mut race_state = RaceState::default();
-	let mut stall_countdown = Instant::now();
 
 	let mut source_retry_backoff = retry_backoff();
 	let mut source_client_is_online = true;
@@ -250,6 +253,7 @@ pub async fn run<P: MessageRace, SC: SourceClient<P>, TC: TargetClient<P>>(
 	let target_best_nonces = futures::future::Fuse::terminated();
 	let target_finalized_nonces = futures::future::Fuse::terminated();
 	let target_submit_proof = futures::future::Fuse::terminated();
+	let target_tx_tracker = futures::future::Fuse::terminated();
 	let target_go_offline_future = futures::future::Fuse::terminated();
 
 	futures::pin_mut!(
@@ -261,6 +265,7 @@ pub async fn run<P: MessageRace, SC: SourceClient<P>, TC: TargetClient<P>>(
 		target_best_nonces,
 		target_finalized_nonces,
 		target_submit_proof,
+		target_tx_tracker,
 		target_go_offline_future,
 	);
 
@@ -343,11 +348,7 @@ pub async fn run<P: MessageRace, SC: SourceClient<P>, TC: TargetClient<P>>(
 							nonces,
 						);
 
-						let prev_best_at_target = strategy.best_at_target();
 						strategy.best_target_nonces_updated(nonces, &mut race_state);
-						if strategy.best_at_target() != prev_best_at_target {
-							stall_countdown = Instant::now();
-						}
 					},
 					&mut target_go_offline_future,
 					async_std::task::sleep,
@@ -400,23 +401,37 @@ pub async fn run<P: MessageRace, SC: SourceClient<P>, TC: TargetClient<P>>(
 				target_client_is_online = process_future_result(
 					proof_submit_result,
 					&mut target_retry_backoff,
-					|nonces_range| {
+					|artifacts: NoncesSubmitArtifacts<TC::TransactionTracker>| {
 						log::debug!(
 							target: "bridge",
 							"Successfully submitted proof of nonces {:?} to {}",
-							nonces_range,
+							artifacts.nonces,
 							P::target_name(),
 						);
 
 						race_state.nonces_to_submit = None;
-						race_state.nonces_submitted = Some(nonces_range);
-						stall_countdown = Instant::now();
+						race_state.nonces_submitted = Some(artifacts.nonces);
+						target_tx_tracker.set(artifacts.tx_tracker.wait().fuse());
 					},
 					&mut target_go_offline_future,
 					async_std::task::sleep,
 					|| format!("Error submitting proof {}", P::target_name()),
 				).fail_if_connection_error(FailedClient::Target)?;
 			},
+			target_transaction_status = target_tx_tracker => {
+				if target_transaction_status == TrackedTransactionStatus::Lost {
+					log::warn!(
+						target: "bridge",
+						"{} -> {} race has stalled. State: {:?}. Strategy: {:?}",
+						P::source_name(),
+						P::target_name(),
+						race_state,
+						strategy,
+					);
+
+					return Err(FailedClient::Both);
+				}
+			},
 
 			// when we're ready to retry request
 			_ = source_go_offline_future => {
@@ -429,24 +444,6 @@ pub async fn run<P: MessageRace, SC: SourceClient<P>, TC: TargetClient<P>>(
 
 		progress_context = print_race_progress::<P, _>(progress_context, &strategy);
 
-		if stall_countdown.elapsed() > stall_timeout {
-			log::warn!(
-				target: "bridge",
-				"{} -> {} race has stalled. State: {:?}. Strategy: {:?}",
-				P::source_name(),
-				P::target_name(),
-				race_state,
-				strategy,
-			);
-
-			return Err(FailedClient::Both)
-		} else if race_state.nonces_to_submit.is_none() &&
-			race_state.nonces_submitted.is_none() &&
-			strategy.is_empty()
-		{
-			stall_countdown = Instant::now();
-		}
-
 		if source_client_is_online {
 			source_client_is_online = false;
 

bridges/relays/messages/src/message_race_receiving.rs

@@ -16,7 +16,7 @@
 use crate::{
 	message_lane::{MessageLane, SourceHeaderIdOf, TargetHeaderIdOf},
 	message_lane_loop::{
-		SourceClient as MessageLaneSourceClient, SourceClientState,
+		NoncesSubmitArtifacts, SourceClient as MessageLaneSourceClient, SourceClientState,
 		TargetClient as MessageLaneTargetClient, TargetClientState,
 	},
 	message_race_loop::{
@@ -31,7 +31,7 @@ use async_trait::async_trait;
 use bp_messages::MessageNonce;
 use futures::stream::FusedStream;
 use relay_utils::FailedClient;
-use std::{marker::PhantomData, ops::RangeInclusive, time::Duration};
+use std::{marker::PhantomData, ops::RangeInclusive};
 
 /// Message receiving confirmations delivery strategy.
 type ReceivingConfirmationsBasicStrategy<P> = BasicStrategy<
@@ -49,7 +49,6 @@ pub async fn run<P: MessageLane>(
 	source_state_updates: impl FusedStream<Item = SourceClientState<P>>,
 	target_client: impl MessageLaneTargetClient<P>,
 	target_state_updates: impl FusedStream<Item = TargetClientState<P>>,
-	stall_timeout: Duration,
 	metrics_msg: Option<MessageLaneLoopMetrics>,
 ) -> Result<(), FailedClient> {
 	crate::message_race_loop::run(
@@ -65,7 +64,6 @@ pub async fn run<P: MessageLane>(
 			_phantom: Default::default(),
 		},
 		source_state_updates,
-		stall_timeout,
 		ReceivingConfirmationsBasicStrategy::<P>::new(),
 	)
 	.await
@@ -157,6 +155,7 @@ where
 {
 	type Error = C::Error;
 	type TargetNoncesData = ();
+	type TransactionTracker = C::TransactionTracker;
 
 	async fn require_source_header(&self, id: TargetHeaderIdOf<P>) {
 		self.client.require_target_header_on_source(id).await
@@ -182,9 +181,10 @@ where
 		generated_at_block: TargetHeaderIdOf<P>,
 		nonces: RangeInclusive<MessageNonce>,
 		proof: P::MessagesReceivingProof,
-	) -> Result<RangeInclusive<MessageNonce>, Self::Error> {
-		self.client.submit_messages_receiving_proof(generated_at_block, proof).await?;
-		Ok(nonces)
+	) -> Result<NoncesSubmitArtifacts<Self::TransactionTracker>, Self::Error> {
+		let tx_tracker =
+			self.client.submit_messages_receiving_proof(generated_at_block, proof).await?;
+		Ok(NoncesSubmitArtifacts { nonces, tx_tracker })
 	}
 }