Squashed 'bridges/' changes from b2099c5..23dda62 (#3369)

23dda62 Rococo <> Wococo messages relay (#1030)
bcde21d Update the wasm builder to substrate master (#1029)
a8318ce Make target signer optional when sending message. (#1018)
f8602e1 Fix insufficient balance when send message. (#1020)
d95c0a7 greedy relayer don't need message dispatch to be prepaid if dispatch is supposed to be paid at the target chain (#1016)
ad5876f Update types. (#1027)
116cbbc CI: fix starting the pipeline (#1022)
7e0fadd Add temporary `canary` job (#1019)
6787091 Update types to contain dispatch_fee_payment (#1017)
03f79ad Allow Root to assume SourceAccount. (#1011)
372d019 Return dispatch_fee_payment from message details RPC (#1014)
604eb1c Relay basic single-bit message dispatch results back to the source chain (#935)
bf52fff Use plain source_queue view when selecting nonces for delivery (#1010)
fc5cf7d pay dispatch fee at target chain (#911)
1e35477 Bump Substrate to `286d7ce` (#1006)
7ad07b3 Add --only-mandatory-headers mode (#1004)
5351dc9 Messages relayer operating mode (#995)
9bc29a7 Rococo <> Wococo relayer balance guard (#998)
bc17341 rename messages_dispatch_weight -> message_details (#996)
95be244 Bump Rococo and Wococo spec versions (#999)
c35567b Move ChainWithBalances::NativeBalance -> Chain::Balance (#990)
1bfece1 Fix some nits (#988)
334ea0f Increase pause before starting relays again (#989)
7fb8248 Fix clippy in test code (#993)
d60ae50 fix clippy issues (#991)
75ca813 Make sure GRANDPA shares state with RPC. (#987)
da2a38a Bump Substrate (#986)
5a9862f Update submit finality proof weight formula (#981)
69df513 Flag for rejecting all outbound messages (#982)
14d0506 Add script to setup bench machine. (#984)
e74e8ab Move CI from GitHub Actions to GitLab (#814)
c5ca5dd Custom justification verification (#979)
643f10d Always run on-demand headers relay in complex relay (#975)
a35b0ef Add JSON type definitions for Rococo<>Wococo bridge (#977)
0eb83f2 Update cargo.deny (#980)
e1d1f4c Bump Rococo/Wococo spec_version (#976)
deac90d increase pause before starting relays (#974)
68d6d79 Revert to use InspectCmd, bump substrate `6bef4f4` (#966)
66e1508 Avoid hashing headers twice in verify_justification (#973)
a31844f Bump `environmental` dependency (#972)
2a4c29a in auto-relays keep trying to connect to nodes until connection is established (#971)
0e767b3 removed stray file (#969)
b9545dc Serve multiple lanes with single complex relay instance (#964)
73419f4 Correct type error (#968)
bac256f Start finality relay spec-version guards for Rococo <> Wococo finality relays (#965)
bfd7037 pass source and target chain ids to account_ownership_proof (#963)
8436073 Upstream changes from Polkadot repo (#961)
e58d851 Increase account endowment amount (#960)

git-subtree-dir: bridges
git-subtree-split: 23dda6248236b27f20d76cbedc30e189cc6f736c

polkadot/bridges/relays/finality/src/finality_loop.rs

@@ -39,8 +39,6 @@ use std::{
 /// Finality proof synchronization loop parameters.
 #[derive(Debug, Clone)]
 pub struct FinalitySyncParams {
-	/// If `true`, then the separate async task for running finality loop is NOT spawned.
-	pub is_on_demand_task: bool,
 	/// Interval at which we check updates on both clients. Normally should be larger than
 	/// `min(source_block_time, target_block_time)`.
 	///
@@ -60,6 +58,8 @@ pub struct FinalitySyncParams {
 	pub recent_finality_proofs_limit: usize,
 	/// Timeout before we treat our transactions as lost and restart the whole sync process.
 	pub stall_timeout: Duration,
+	/// If true, only mandatory headers are relayed.
+	pub only_mandatory_headers: bool,
 }
 
 /// Source client used in finality synchronization loop.
@@ -107,7 +107,6 @@ pub async fn run<P: FinalitySyncPipeline>(
 ) -> Result<(), String> {
 	let exit_signal = exit_signal.shared();
 	relay_utils::relay_loop(source_client, target_client)
-		.spawn_loop_task(!sync_params.is_on_demand_task)
 		.with_metrics(Some(metrics_prefix::<P>()), metrics_params)
 		.loop_metric(|registry, prefix| SyncLoopMetrics::new(registry, prefix))?
 		.standalone_metric(|registry, prefix| GlobalMetrics::new(registry, prefix))?
@@ -367,7 +366,7 @@ where
 	}
 }
 
-async fn select_header_to_submit<P, SC, TC>(
+pub(crate) async fn select_header_to_submit<P, SC, TC>(
 	source_client: &SC,
 	target_client: &TC,
 	finality_proofs_stream: &mut RestartableFinalityProofsStream<SC::FinalityProofsStream>,
@@ -400,6 +399,11 @@ where
 	.await?;
 	let (mut unjustified_headers, mut selected_finality_proof) = match selected_finality_proof {
 		SelectedFinalityProof::Mandatory(header, finality_proof) => return Ok(Some((header, finality_proof))),
+		_ if sync_params.only_mandatory_headers => {
+			// we are not reading finality proofs from the stream, so eventually it'll break
+			// but we don't care about transient proofs at all, so it is acceptable
+			return Ok(None);
+		}
 		SelectedFinalityProof::Regular(unjustified_headers, header, finality_proof) => {
 			(unjustified_headers, Some((header, finality_proof)))
 		}