Merge pull request paritytech#106 from paritytech/andre/fix-finality-notification

Fix sending of finality notification

Author: andresilva

src/lib.rs

@@ -113,8 +113,7 @@ impl<H, N> Precommit<H, N> {
 
 /// A primary proposed block, this is a broadcast of the last round's estimate.
 #[derive(Clone, PartialEq, Eq)]
-#[cfg_attr(any(feature = "std", test), derive(
-Debug))]
+#[cfg_attr(any(feature = "std", test), derive(Debug))]
 #[cfg_attr(feature = "derive-codec", derive(Encode, Decode))]
 pub struct PrimaryPropose<H, N> {
 	/// The target block's hash.
@@ -130,8 +129,7 @@ impl<H, N> PrimaryPropose<H, N> {
 }
 
 #[derive(Clone, PartialEq)]
-#[cfg_attr(any(feature = "std", test), derive(
-Debug))]
+#[cfg_attr(any(feature = "std", test), derive(Debug))]
 pub enum Error {
 	NotDescendent,
 }
@@ -219,8 +217,7 @@ pub struct Equivocation<Id, V, S> {
 
 /// A protocol message or vote.
 #[derive(Clone, PartialEq, Eq)]
-#[cfg_attr(any(feature = "std", test), derive(
-Debug))]
+#[cfg_attr(any(feature = "std", test), derive(Debug))]
 #[cfg_attr(feature = "derive-codec", derive(Encode, Decode))]
 pub enum Message<H, N> {
 	/// A prevote message.
@@ -247,8 +244,7 @@ impl<H, N: Copy> Message<H, N> {
 
 /// A signed message.
 #[derive(Clone, PartialEq, Eq)]
-#[cfg_attr(any(feature = "std", test), derive(
-Debug))]
+#[cfg_attr(any(feature = "std", test), derive(Debug))]
 #[cfg_attr(feature = "derive-codec", derive(Encode, Decode))]
 pub struct SignedMessage<H, N, S, Id> {
 	/// The internal message which has been signed.
@@ -270,8 +266,7 @@ impl<H, N: Copy, S, Id> SignedMessage<H, N, S, Id> {
 
 /// A commit message which is an aggregate of precommits.
 #[derive(Clone, PartialEq, Eq)]
-#[cfg_attr(any(feature = "std", test), derive(
-Debug))]
+#[cfg_attr(any(feature = "std", test), derive(Debug))]
 #[cfg_attr(feature = "derive-codec", derive(Encode, Decode))]
 pub struct Commit<H, N, S, Id> {
 	/// The target block's hash.
@@ -284,8 +279,7 @@ pub struct Commit<H, N, S, Id> {
 
 /// A signed prevote message.
 #[derive(Clone, PartialEq, Eq)]
-#[cfg_attr(any(feature = "std", test), derive(
-Debug))]
+#[cfg_attr(any(feature = "std", test), derive(Debug))]
 #[cfg_attr(feature = "derive-codec", derive(Encode, Decode))]
 pub struct SignedPrevote<H, N, S, Id> {
 	/// The prevote message which has been signed.
@@ -298,8 +292,7 @@ pub struct SignedPrevote<H, N, S, Id> {
 
 /// A signed precommit message.
 #[derive(Clone, PartialEq, Eq)]
-#[cfg_attr(any(feature = "std", test), derive(
-Debug))]
+#[cfg_attr(any(feature = "std", test), derive(Debug))]
 #[cfg_attr(feature = "derive-codec", derive(Encode, Decode))]
 pub struct SignedPrecommit<H, N, S, Id> {
 	/// The precommit message which has been signed.
@@ -312,8 +305,7 @@ pub struct SignedPrecommit<H, N, S, Id> {
 
 /// A commit message with compact representation of authentication data.
 #[derive(Clone, PartialEq, Eq)]
-#[cfg_attr(any(feature = "std", test), derive(
-Debug))]
+#[cfg_attr(any(feature = "std", test), derive(Debug))]
 #[cfg_attr(feature = "derive-codec", derive(Encode, Decode))]
 pub struct CompactCommit<H, N, S, Id> {
 	/// The target block's hash.
@@ -332,8 +324,7 @@ pub struct CompactCommit<H, N, S, Id> {
 /// This message contains a "base", which is a block all of the vote-targets are
 /// a descendent of.
 #[derive(Clone, PartialEq, Eq)]
-#[cfg_attr(any(feature = "std", test), derive(
-Debug))]
+#[cfg_attr(any(feature = "std", test), derive(Debug))]
 #[cfg_attr(feature = "derive-codec", derive(Encode, Decode))]
 pub struct CatchUp<H, N, S, Id> {
 	/// Round number.
@@ -520,8 +511,7 @@ pub fn process_commit_validation_result<H, N>(
 
 /// Historical votes seen in a round.
 #[derive(Default, Clone, PartialEq, Eq)]
-#[cfg_attr(any(feature = "std", test), derive(
-Debug))]
+#[cfg_attr(any(feature = "std", test), derive(Debug))]
 #[cfg_attr(feature = "derive-codec", derive(Encode, Decode))]
 pub struct HistoricalVotes<H, N, S, Id> {
 	seen: Vec<SignedMessage<H, N, S, Id>>,

src/round.rs

@@ -160,8 +160,7 @@ impl<Id: Ord + Eq + Clone, Vote: Clone + Eq, Signature: Clone + Eq> VoteTracker<
 
 /// State of the round.
 #[derive(PartialEq, Clone)]
-#[cfg_attr(any(feature = "std", test), derive(
-Debug))]
+#[cfg_attr(any(feature = "std", test), derive(Debug))]
 #[cfg_attr(feature = "derive-codec", derive(Encode, Decode))]
 pub struct State<H, N> {
 	/// The prevote-GHOST block.

src/voter/voting_round.rs

@@ -608,17 +608,23 @@ impl<H, N, E: Environment<H, N>> VotingRound<H, N, E> where
 
 	// notify when new blocks are finalized or when the round-estimate is updated
 	fn notify(&mut self, last_state: RoundState<H, N>, new_state: RoundState<H, N>) {
-		if last_state == new_state { return }
-
-		if let Some(ref b) = self.bridged_round_state {
-			b.update(new_state.clone());
+		if last_state != new_state {
+			if let Some(ref b) = self.bridged_round_state {
+				b.update(new_state.clone());
+			}
 		}
 
-		if last_state.finalized != new_state.finalized && new_state.completable {
-			// send notification only when the round is completable and we've cast votes.
-			// this is a workaround that ensures when we re-instantiate the voter after
-			// a shutdown, we never re-create the same round with a base that was finalized
-			// in this round or after.
+		// send notification only when the round is completable and we've cast votes.
+		// this is a workaround that ensures when we re-instantiate the voter after
+		// a shutdown, we never re-create the same round with a base that was finalized
+		// in this round or after.
+		// we try to notify if either the round state changed or if we haven't
+		// sent any notification yet (this is to guard against seeing enough
+		// votes to finalize before having precommited)
+		let state_changed = last_state.finalized != new_state.finalized;
+		let sent_finality_notifications = self.best_finalized.is_some();
+
+		if new_state.completable && (state_changed || !sent_finality_notifications) {
 			if let (&Some(State::Precommitted), Some((ref f_hash, ref f_number))) = (&self.state, new_state.finalized) {
 				let commit = Commit {
 					target_hash: f_hash.clone(),