pvf-precheck: PVF pre-checker subsystem (#4643)

This commit implements the last major piece of #3211: the subsystem that
tracks PVFs that require voting, issues pre-check requests to
candidate-validation and makes sure that the votes are submitted to the
chain.

polkadot/node/overseer/src/dummy.rs

@@ -89,6 +89,7 @@ pub fn dummy_overseer_builder<'a, Spawner, SupportsParachains>(
 		DummySubsystem,
 		DummySubsystem,
 		DummySubsystem,
+		DummySubsystem,
 	>,
 	SubsystemError,
 >
@@ -129,6 +130,7 @@ pub fn one_for_all_overseer_builder<'a, Spawner, SupportsParachains, Sub>(
 		Sub,
 		Sub,
 		Sub,
+		Sub,
 	>,
 	SubsystemError,
 >
@@ -155,7 +157,8 @@ where
 		+ Subsystem<OverseerSubsystemContext<GossipSupportMessage>, SubsystemError>
 		+ Subsystem<OverseerSubsystemContext<DisputeCoordinatorMessage>, SubsystemError>
 		+ Subsystem<OverseerSubsystemContext<DisputeDistributionMessage>, SubsystemError>
-		+ Subsystem<OverseerSubsystemContext<ChainSelectionMessage>, SubsystemError>,
+		+ Subsystem<OverseerSubsystemContext<ChainSelectionMessage>, SubsystemError>
+		+ Subsystem<OverseerSubsystemContext<PvfCheckerMessage>, SubsystemError>,
 {
 	let metrics = <OverseerMetrics as MetricsTrait>::register(registry)?;
 
@@ -167,6 +170,7 @@ where
 		.bitfield_signing(subsystem.clone())
 		.candidate_backing(subsystem.clone())
 		.candidate_validation(subsystem.clone())
+		.pvf_checker(subsystem.clone())
 		.chain_api(subsystem.clone())
 		.collation_generation(subsystem.clone())
 		.collator_protocol(subsystem.clone())

polkadot/node/overseer/src/lib.rs

@@ -84,8 +84,8 @@ use polkadot_node_subsystem_types::messages::{
 	BitfieldSigningMessage, CandidateBackingMessage, CandidateValidationMessage, ChainApiMessage,
 	ChainSelectionMessage, CollationGenerationMessage, CollatorProtocolMessage,
 	DisputeCoordinatorMessage, DisputeDistributionMessage, GossipSupportMessage,
-	NetworkBridgeEvent, NetworkBridgeMessage, ProvisionerMessage, RuntimeApiMessage,
-	StatementDistributionMessage,
+	NetworkBridgeEvent, NetworkBridgeMessage, ProvisionerMessage, PvfCheckerMessage,
+	RuntimeApiMessage, StatementDistributionMessage,
 };
 pub use polkadot_node_subsystem_types::{
 	errors::{SubsystemError, SubsystemResult},
@@ -420,6 +420,9 @@ pub struct Overseer<SupportsParachains> {
 	#[subsystem(no_dispatch, CandidateValidationMessage)]
 	candidate_validation: CandidateValidation,
 
+	#[subsystem(no_dispatch, PvfCheckerMessage)]
+	pvf_checker: PvfChecker,
+
 	#[subsystem(no_dispatch, CandidateBackingMessage)]
 	candidate_backing: CandidateBacking,
 

polkadot/node/overseer/src/tests.rs

@@ -920,9 +920,9 @@ fn test_chain_selection_msg() -> ChainSelectionMessage {
 // Checks that `stop`, `broadcast_signal` and `broadcast_message` are implemented correctly.
 #[test]
 fn overseer_all_subsystems_receive_signals_and_messages() {
-	const NUM_SUBSYSTEMS: usize = 20;
-	// -3 for BitfieldSigning, GossipSupport and AvailabilityDistribution
-	const NUM_SUBSYSTEMS_MESSAGED: usize = NUM_SUBSYSTEMS - 3;
+	const NUM_SUBSYSTEMS: usize = 21;
+	// -4 for BitfieldSigning, GossipSupport, AvailabilityDistribution and PvfCheckerSubsystem.
+	const NUM_SUBSYSTEMS_MESSAGED: usize = NUM_SUBSYSTEMS - 4;
 
 	let spawner = sp_core::testing::TaskExecutor::new();
 	executor::block_on(async move {
@@ -1005,6 +1005,7 @@ fn overseer_all_subsystems_receive_signals_and_messages() {
 		handle
 			.send_msg_anon(AllMessages::ChainSelection(test_chain_selection_msg()))
 			.await;
+		// handle.send_msg_anon(AllMessages::PvfChecker(test_pvf_checker_msg())).await;
 
 		// Wait until all subsystems have received. Otherwise the messages might race against
 		// the conclude signal.
@@ -1058,6 +1059,7 @@ fn context_holds_onto_message_until_enough_signals_received() {
 	let (dispute_coordinator_bounded_tx, _) = metered::channel(CHANNEL_CAPACITY);
 	let (dispute_distribution_bounded_tx, _) = metered::channel(CHANNEL_CAPACITY);
 	let (chain_selection_bounded_tx, _) = metered::channel(CHANNEL_CAPACITY);
+	let (pvf_checker_bounded_tx, _) = metered::channel(CHANNEL_CAPACITY);
 
 	let (candidate_validation_unbounded_tx, _) = metered::unbounded();
 	let (candidate_backing_unbounded_tx, _) = metered::unbounded();
@@ -1079,6 +1081,7 @@ fn context_holds_onto_message_until_enough_signals_received() {
 	let (dispute_coordinator_unbounded_tx, _) = metered::unbounded();
 	let (dispute_distribution_unbounded_tx, _) = metered::unbounded();
 	let (chain_selection_unbounded_tx, _) = metered::unbounded();
+	let (pvf_checker_unbounded_tx, _) = metered::unbounded();
 
 	let channels_out = ChannelsOut {
 		candidate_validation: candidate_validation_bounded_tx.clone(),
@@ -1101,6 +1104,7 @@ fn context_holds_onto_message_until_enough_signals_received() {
 		dispute_coordinator: dispute_coordinator_bounded_tx.clone(),
 		dispute_distribution: dispute_distribution_bounded_tx.clone(),
 		chain_selection: chain_selection_bounded_tx.clone(),
+		pvf_checker: pvf_checker_bounded_tx.clone(),
 
 		candidate_validation_unbounded: candidate_validation_unbounded_tx.clone(),
 		candidate_backing_unbounded: candidate_backing_unbounded_tx.clone(),
@@ -1122,6 +1126,7 @@ fn context_holds_onto_message_until_enough_signals_received() {
 		dispute_coordinator_unbounded: dispute_coordinator_unbounded_tx.clone(),
 		dispute_distribution_unbounded: dispute_distribution_unbounded_tx.clone(),
 		chain_selection_unbounded: chain_selection_unbounded_tx.clone(),
+		pvf_checker_unbounded: pvf_checker_unbounded_tx.clone(),
 	};
 
 	let (mut signal_tx, signal_rx) = metered::channel(CHANNEL_CAPACITY);