finality_target adjustments

Author: drahnr

node/core/approval-voting/src/lib.rs

@@ -1180,7 +1180,7 @@ async fn handle_approved_ancestor(
 	target: Hash,
 	lower_bound: BlockNumber,
 	wakeups: &Wakeups,
-) -> SubsystemResult<Option<(Hash, BlockNumber)>> {
+) -> SubsystemResult<Option<(Hash, BlockNumber, Vec<(Hash, SessionIndex, Vec<CandidateHash>)>)>> {
 	const MAX_TRACING_WINDOW: usize = 200;
 	const ABNORMAL_DEPTH_THRESHOLD: usize = 5;
 
@@ -1228,6 +1228,8 @@ async fn handle_approved_ancestor(
 		Vec::new()
 	};
 
+	let mut candidates: Vec<_> = Vec::new();
+
 	let mut bits: BitVec<Lsb0, u8> = Default::default();
 	for (i, block_hash) in std::iter::once(target).chain(ancestry).enumerate() {
 		// Block entries should be present as the assumption is that
@@ -1248,6 +1250,8 @@ async fn handle_approved_ancestor(
 			Some(b) => b,
 		};
 
+		candidates.push((block_hash, entry.session(), entry.candidates().iter().map(|(_idx, candidate_hash)| *candidate_hash ).collect::<Vec<_>>()));
+
 		// even if traversing millions of blocks this is fairly cheap and always dwarfed by the
 		// disk lookups.
 		bits.push(entry.is_fully_approved());
@@ -1366,8 +1370,11 @@ async fn handle_approved_ancestor(
 		},
 	);
 
+	let all_approved_max = all_approved_max.map(|(hash, block_number)| {
+		(hash, block_number, candidates)
+	});
 	match all_approved_max {
-		Some((ref hash, ref number)) => {
+		Some((ref hash, ref number, _)) => {
 			span.add_uint_tag("approved-number", *number as u64);
 			span.add_string_fmt_debug_tag("approved-hash", hash);
 		}

node/service/src/grandpa_support.rs

@@ -155,7 +155,7 @@ impl<B> grandpa::VotingRule<PolkadotBlock, B> for ApprovalCheckingVotingRule
 				let diff = best_number.saturating_sub(base_number);
 				if diff >= MAX_APPROVAL_CHECKING_FINALITY_LAG {
 					// Catch up to the best, with some extra lag.
-					let target_number = best_number - MAX_APPROVAL_CHECKING_FINALITY_LAG;
+					let target_number = best_number.saturating_sub(MAX_APPROVAL_CHECKING_FINALITY_LAG);
 					if target_number >= current_number {
 						Some((current_hash, current_number))
 					} else {

node/service/src/relay_chain_selection.rs

@@ -39,7 +39,7 @@ use {
 	polkadot_primitives::v1::{
 		Hash, BlockNumber, Block as PolkadotBlock, Header as PolkadotHeader,
 	},
-	polkadot_subsystem::messages::{ApprovalVotingMessage, ChainSelectionMessage},
+	polkadot_subsystem::messages::{ApprovalVotingMessage, ChainSelectionMessage, DisputeCoordinatorMessage},
 	polkadot_node_subsystem_util::metrics::{self, prometheus},
 	polkadot_overseer::Handle,
 	futures::channel::oneshot,
@@ -321,7 +321,7 @@ impl<B> SelectChain<PolkadotBlock> for SelectRelayChain<B>
 		let initial_leaf_number = self.block_number(initial_leaf)?;
 
 		// 2. Constrain according to `ApprovedAncestor`.
-		let (subchain_head, subchain_number) = {
+		let (subchain_head, subchain_number, subchain_block_descriptions) = {
 
 			let (tx, rx) = oneshot::channel();
 			overseer.send_msg(
@@ -338,8 +338,8 @@ impl<B> SelectChain<PolkadotBlock> for SelectRelayChain<B>
 				.map_err(|e| ConsensusError::Other(Box::new(e)))?
 			{
 				// No approved ancestors means target hash is maximal vote.
-				None => (target_hash, target_number),
-				Some((s_h, s_n)) => (s_h, s_n),
+				None => (target_hash, target_number, Vec::new()),
+				Some((s_h, s_n, s_bd)) => (s_h, s_n, s_bd),
 			}
 		};
 
@@ -348,6 +348,17 @@ impl<B> SelectChain<PolkadotBlock> for SelectRelayChain<B>
 
 		// 3. Constrain according to disputes:
 		// TODO: https://github.com/paritytech/polkadot/issues/3164
+		let (tx, rx) = oneshot::channel();
+		overseer.send_msg(DisputeCoordinatorMessage::DetermineUndisputedChain{
+			base_number: subchain_number,
+			block_descriptions: subchain_block_descriptions,
+			tx,
+		}).await;
+		let (subchain_numbner, subchain_head) = rx.await
+			.map_err(Error::OverseerDisconnected)
+			.map_err(|e| ConsensusError::Other(Box::new(e)))?
+			.unwrap_or_else(|| (subchain_number, subchain_head));
+
 		self.metrics.note_disputes_finality_lag(0);
 
 		// 4. Apply the maximum safeguard to the finality lag.

node/subsystem-types/src/messages.rs

@@ -814,7 +814,7 @@ pub enum ApprovalVotingMessage {
 	///
 	/// It can also return the same block hash, if that is acceptable to vote upon.
 	/// Return `None` if the input hash is unrecognized.
-	ApprovedAncestor(Hash, BlockNumber, oneshot::Sender<Option<(Hash, BlockNumber)>>),
+	ApprovedAncestor(Hash, BlockNumber, oneshot::Sender<Option<(Hash, BlockNumber, Vec<(Hash, SessionIndex, Vec<CandidateHash>)>)>>),
 }
 
 /// Message to the Approval Distribution subsystem.