grandpa: track multiple live rounds in voter set state (#3298)

* grandpa: track multiple live rounds in voter set state

* grandpa: don't assume rounds are completed in-order

* grandpa: fix tests

* grandpa: don't assume round is being tracked on Environment::completed

* grandpa: fix missing import in test

substrate/core/finality-grandpa/src/aux_schema.rs

@@ -30,7 +30,9 @@ use fg_primitives::AuthorityId;
 
 use crate::authorities::{AuthoritySet, SharedAuthoritySet, PendingChange, DelayKind};
 use crate::consensus_changes::{SharedConsensusChanges, ConsensusChanges};
-use crate::environment::{CompletedRound, CompletedRounds, HasVoted, SharedVoterSetState, VoterSetState};
+use crate::environment::{
+	CompletedRound, CompletedRounds, CurrentRounds, HasVoted, SharedVoterSetState, VoterSetState,
+};
 use crate::NewAuthoritySet;
 
 const VERSION_KEY: &[u8] = b"grandpa_schema_version";
@@ -155,6 +157,9 @@ fn migrate_from_version0<Block: BlockT, B, G>(
 		let base = last_round_state.prevote_ghost
 			.expect("state is for completed round; completed rounds must have a prevote ghost; qed.");
 
+		let mut current_rounds = CurrentRounds::new();
+		current_rounds.insert(last_round_number + 1, HasVoted::No);
+
 		let set_state = VoterSetState::Live {
 			completed_rounds: CompletedRounds::new(
 				CompletedRound {
@@ -166,7 +171,7 @@ fn migrate_from_version0<Block: BlockT, B, G>(
 				set_id,
 				&new_set,
 			),
-			current_round: HasVoted::No,
+			current_rounds,
 		};
 
 		backend.insert_aux(&[(SET_STATE_KEY, set_state.encode().as_slice())], &[])?;
@@ -223,9 +228,12 @@ fn migrate_from_version1<Block: BlockT, B, G>(
 				let base = set_state.prevote_ghost
 					.expect("state is for completed round; completed rounds must have a prevote ghost; qed.");
 
+				let mut current_rounds = CurrentRounds::new();
+				current_rounds.insert(last_round_number + 1, HasVoted::No);
+
 				VoterSetState::Live {
 					completed_rounds: completed_rounds(last_round_number, set_state, base),
-					current_round: HasVoted::No,
+					current_rounds,
 				}
 			},
 			None => {
@@ -233,10 +241,11 @@ fn migrate_from_version1<Block: BlockT, B, G>(
 				let base = set_state.prevote_ghost
 					.expect("state is for completed round; completed rounds must have a prevote ghost; qed.");
 
-				VoterSetState::Live {
-					completed_rounds: completed_rounds(0, set_state, base),
-					current_round: HasVoted::No,
-				}
+				VoterSetState::live(
+					set_id,
+					&set,
+					base,
+				)
 			},
 		};
 
@@ -300,19 +309,11 @@ pub(crate) fn load_persistent<Block: BlockT, B, G>(
 						let base = state.prevote_ghost
 							.expect("state is for completed round; completed rounds must have a prevote ghost; qed.");
 
-						VoterSetState::Live {
-							completed_rounds: CompletedRounds::new(
-								CompletedRound {
-									number: 0,
-									votes: Vec::new(),
-									base,
-									state,
-								},
-								set.current().0,
-								&set,
-							),
-							current_round: HasVoted::No,
-						}
+						VoterSetState::live(
+							set.current().0,
+							&set,
+							base,
+						)
 					}
 				};
 
@@ -338,19 +339,12 @@ pub(crate) fn load_persistent<Block: BlockT, B, G>(
 	let base = state.prevote_ghost
 		.expect("state is for completed round; completed rounds must have a prevote ghost; qed.");
 
-	let genesis_state = VoterSetState::Live {
-		completed_rounds: CompletedRounds::new(
-			CompletedRound {
-				number: 0,
-				votes: Vec::new(),
-				state,
-				base,
-			},
-			0,
-			&genesis_set,
-		),
-		current_round: HasVoted::No,
-	};
+	let genesis_state = VoterSetState::live(
+		0,
+		&genesis_set,
+		base,
+	);
+
 	backend.insert_aux(
 		&[
 			(AUTHORITY_SET_KEY, genesis_set.encode().as_slice()),
@@ -396,23 +390,11 @@ pub(crate) fn update_authority_set<Block: BlockT, F, R>(
 		// we also overwrite the "last completed round" entry with a blank slate
 		// because from the perspective of the finality gadget, the chain has
 		// reset.
-		let round_state = RoundState::genesis((
-			new_set.canon_hash.clone(),
-			new_set.canon_number.clone(),
-		));
-		let set_state = VoterSetState::<Block>::Live {
-			completed_rounds: CompletedRounds::new(
-				CompletedRound {
-					number: 0,
-					state: round_state,
-					votes: Vec::new(),
-					base: (new_set.canon_hash, new_set.canon_number),
-				},
-				new_set.set_id,
-				&set,
-			),
-			current_round: HasVoted::No,
-		};
+		let set_state = VoterSetState::<Block>::live(
+			new_set.set_id,
+			&set,
+			(new_set.canon_hash, new_set.canon_number),
+		);
 		let encoded = set_state.encode();
 
 		write_aux(&[
@@ -527,6 +509,9 @@ mod test {
 			},
 		);
 
+		let mut current_rounds = CurrentRounds::new();
+		current_rounds.insert(round_number + 1, HasVoted::No);
+
 		assert_eq!(
 			&*set_state.read(),
 			&VoterSetState::Live {
@@ -540,7 +525,7 @@ mod test {
 					set_id,
 					&*authority_set.inner().read(),
 				),
-				current_round: HasVoted::No,
+				current_rounds,
 			},
 		);
 	}
@@ -614,6 +599,9 @@ mod test {
 			},
 		);
 
+		let mut current_rounds = CurrentRounds::new();
+		current_rounds.insert(round_number + 1, HasVoted::No);
+
 		assert_eq!(
 			&*set_state.read(),
 			&VoterSetState::Live {
@@ -627,7 +615,7 @@ mod test {
 					set_id,
 					&*authority_set.inner().read(),
 				),
-				current_round: HasVoted::No,
+				current_rounds,
 			},
 		);
 	}

substrate/core/finality-grandpa/src/communication/gossip.rs

@@ -1248,26 +1248,16 @@ mod tests {
 	// dummy voter set state
 	fn voter_set_state() -> SharedVoterSetState<Block> {
 		use crate::authorities::AuthoritySet;
-		use crate::environment::{CompletedRound, CompletedRounds, HasVoted, VoterSetState};
-		use grandpa::round::State as RoundState;
+		use crate::environment::VoterSetState;
 		use primitives::H256;
 
-		let state = RoundState::genesis((H256::zero(), 0));
-		let base = state.prevote_ghost.unwrap();
+		let base = (H256::zero(), 0);
 		let voters = AuthoritySet::genesis(Vec::new());
-		let set_state = VoterSetState::Live {
-			completed_rounds: CompletedRounds::new(
-				CompletedRound {
-					state,
-					number: 0,
-					votes: Vec::new(),
-					base,
-				},
-				0,
-				&voters,
-			),
-			current_round: HasVoted::No,
-		};
+		let set_state = VoterSetState::live(
+			0,
+			&voters,
+			base,
+		);
 
 		set_state.into()
 	}
@@ -1542,16 +1532,19 @@ mod tests {
 		let set_state: SharedVoterSetState<Block> = {
 			let mut completed_rounds = voter_set_state().read().completed_rounds();
 
-			assert!(completed_rounds.push(environment::CompletedRound {
+			completed_rounds.push(environment::CompletedRound {
 				number: 1,
 				state: grandpa::round::State::genesis(Default::default()),
 				base: Default::default(),
 				votes: Default::default(),
-			}));
+			});
+
+			let mut current_rounds = environment::CurrentRounds::new();
+			current_rounds.insert(2, environment::HasVoted::No);
 
 			let set_state = environment::VoterSetState::<Block>::Live {
 				completed_rounds,
-				current_round: environment::HasVoted::No,
+				current_rounds,
 			};
 
 			set_state.into()

substrate/core/finality-grandpa/src/communication/tests.rs

@@ -141,26 +141,18 @@ fn config() -> crate::Config {
 // dummy voter set state
 fn voter_set_state() -> SharedVoterSetState<Block> {
 	use crate::authorities::AuthoritySet;
-	use crate::environment::{CompletedRound, CompletedRounds, HasVoted, VoterSetState};
+	use crate::environment::VoterSetState;
 	use grandpa::round::State as RoundState;
 	use primitives::H256;
 
 	let state = RoundState::genesis((H256::zero(), 0));
 	let base = state.prevote_ghost.unwrap();
 	let voters = AuthoritySet::genesis(Vec::new());
-	let set_state = VoterSetState::Live {
-		completed_rounds: CompletedRounds::new(
-			CompletedRound {
-				state,
-				number: 0,
-				votes: Vec::new(),
-				base,
-			},
-			0,
-			&voters,
-		),
-		current_round: HasVoted::No,
-	};
+	let set_state = VoterSetState::live(
+		0,
+		&voters,
+		base,
+	);
 
 	set_state.into()
 }

substrate/core/finality-grandpa/src/environment.rs

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
-use std::collections::VecDeque;
+use std::collections::BTreeMap;
 use std::iter::FromIterator;
 use std::sync::Arc;
 use std::time::{Duration, Instant};
@@ -74,11 +74,12 @@ pub struct CompletedRound<Block: BlockT> {
 	pub votes: Vec<SignedMessage<Block>>,
 }
 
-// Data about last completed rounds within a single voter set. Stores NUM_LAST_COMPLETED_ROUNDS and always
-// contains data about at least one round (genesis).
+// Data about last completed rounds within a single voter set. Stores
+// NUM_LAST_COMPLETED_ROUNDS and always contains data about at least one round
+// (genesis).
 #[derive(Debug, Clone, PartialEq)]
 pub struct CompletedRounds<Block: BlockT> {
-	rounds: VecDeque<CompletedRound<Block>>,
+	rounds: Vec<CompletedRound<Block>>,
 	set_id: u64,
 	voters: Vec<AuthorityId>,
 }
@@ -117,8 +118,8 @@ impl<Block: BlockT> CompletedRounds<Block> {
 	)
 		-> CompletedRounds<Block>
 	{
-		let mut rounds = VecDeque::with_capacity(NUM_LAST_COMPLETED_ROUNDS);
-		rounds.push_back(genesis);
+		let mut rounds = Vec::with_capacity(NUM_LAST_COMPLETED_ROUNDS);
+		rounds.push(genesis);
 
 		let voters = voters.current().1.iter().map(|(a, _)| a.clone()).collect();
 		CompletedRounds { rounds, set_id, voters }
@@ -131,32 +132,38 @@ impl<Block: BlockT> CompletedRounds<Block> {
 
 	/// Iterate over all completed rounds.
 	pub fn iter(&self) -> impl Iterator<Item=&CompletedRound<Block>> {
-		self.rounds.iter()
+		self.rounds.iter().rev()
 	}
 
 	/// Returns the last (latest) completed round.
 	pub fn last(&self) -> &CompletedRound<Block> {
-		self.rounds.back()
+		self.rounds.first()
 			.expect("inner is never empty; always contains at least genesis; qed")
 	}
 
-	/// Push a new completed round, returns false if the given round is older
-	/// than the last completed round.
-	pub fn push(&mut self, completed_round: CompletedRound<Block>) -> bool {
-		if self.last().number >= completed_round.number {
-			return false;
+	/// Push a new completed round, oldest round is evicted if number of rounds
+	/// is higher than `NUM_LAST_COMPLETED_ROUNDS`.
+	pub fn push(&mut self, completed_round: CompletedRound<Block>) {
+		use std::cmp::Reverse;
+
+		match self.rounds.binary_search_by_key(
+			&Reverse(completed_round.number),
+			|completed_round| Reverse(completed_round.number),
+		) {
+			Ok(idx) => self.rounds[idx] = completed_round,
+			Err(idx) => self.rounds.insert(idx, completed_round),
+		};
+
+		if self.rounds.len() > NUM_LAST_COMPLETED_ROUNDS {
+			self.rounds.pop();
 		}
-
-		if self.rounds.len() == NUM_LAST_COMPLETED_ROUNDS {
-			self.rounds.pop_front();
-		}
-
-		self.rounds.push_back(completed_round);
-
-		true
 	}
 }
 
+/// A map with voter status information for currently live rounds,
+/// which votes have we cast and what are they.
+pub type CurrentRounds<Block> = BTreeMap<u64, HasVoted<Block>>;
+
 /// The state of the current voter set, whether it is currently active or not
 /// and information related to the previously completed rounds. Current round
 /// voting status is used when restarting the voter, i.e. it will re-use the
@@ -168,8 +175,8 @@ pub enum VoterSetState<Block: BlockT> {
 	Live {
 		/// The previously completed rounds.
 		completed_rounds: CompletedRounds<Block>,
-		/// Vote status for the current round.
-		current_round: HasVoted<Block>,
+		/// Voter status for the currently live rounds.
+		current_rounds: CurrentRounds<Block>,
 	},
 	/// The voter is paused, i.e. not casting or importing any votes.
 	Paused {
@@ -179,6 +186,35 @@ pub enum VoterSetState<Block: BlockT> {
 }
 
 impl<Block: BlockT> VoterSetState<Block> {
+	/// Create a new live VoterSetState with round 0 as a completed round using
+	/// the given genesis state and the given authorities. Round 1 is added as a
+	/// current round (with state `HasVoted::No`).
+	pub(crate) fn live(
+		set_id: u64,
+		authority_set: &AuthoritySet<Block::Hash, NumberFor<Block>>,
+		genesis_state: (Block::Hash, NumberFor<Block>),
+	) -> VoterSetState<Block> {
+		let state = RoundState::genesis((genesis_state.0, genesis_state.1));
+		let completed_rounds = CompletedRounds::new(
+			CompletedRound {
+				number: 0,
+				state,
+				base: (genesis_state.0, genesis_state.1),
+				votes: Vec::new(),
+			},
+			set_id,
+			authority_set,
+		);
+
+		let mut current_rounds = CurrentRounds::new();
+		current_rounds.insert(1, HasVoted::No);
+
+		VoterSetState::Live {
+			completed_rounds,
+			current_rounds,
+		}
+	}
+
 	/// Returns the last completed rounds.
 	pub(crate) fn completed_rounds(&self) -> CompletedRounds<Block> {
 		match self {
@@ -198,10 +234,28 @@ impl<Block: BlockT> VoterSetState<Block> {
 				completed_rounds.last().clone(),
 		}
 	}
+
+	/// Returns the voter set state validating that it includes the given round
+	/// in current rounds and that the voter isn't paused.
+	pub fn with_current_round(&self, round: u64)
+		-> Result<(&CompletedRounds<Block>, &CurrentRounds<Block>), Error>
+	{
+		if let VoterSetState::Live { completed_rounds, current_rounds } = self {
+			if current_rounds.contains_key(&round) {
+				return Ok((completed_rounds, current_rounds));
+			} else {
+				let msg = "Voter acting on a live round we are not tracking.";
+				return Err(Error::Safety(msg.to_string()));
+			}
+		} else {
+			let msg = "Voter acting while in paused state.";
+			return Err(Error::Safety(msg.to_string()));
+		}
+	}
 }
 
 /// Whether we've voted already during a prior run of the program.
-#[derive(Debug, Decode, Encode, PartialEq)]
+#[derive(Clone, Debug, Decode, Encode, PartialEq)]
 pub enum HasVoted<Block: BlockT> {
 	/// Has not voted already in this round.
 	No,
@@ -290,10 +344,16 @@ impl<Block: BlockT> SharedVoterSetState<Block> {
 	}
 
 	/// Return vote status information for the current round.
-	pub(crate) fn has_voted(&self) -> HasVoted<Block> {
+	pub(crate) fn has_voted(&self, round: u64) -> HasVoted<Block> {
 		match &*self.inner.read() {
-			VoterSetState::Live { current_round: HasVoted::Yes(id, vote), .. } =>
-				HasVoted::Yes(id.clone(), vote.clone()),
+			VoterSetState::Live { current_rounds, .. } => {
+				current_rounds.get(&round).and_then(|has_voted| match has_voted {
+					HasVoted::Yes(id, vote) =>
+						Some(HasVoted::Yes(id.clone(), vote.clone())),
+					_ => None,
+				})
+				.unwrap_or(HasVoted::No)
+			},
 			_ => HasVoted::No,
 		}
 	}
@@ -502,7 +562,7 @@ where
 
 		let local_key = crate::is_voter(&self.voters, &self.config.keystore);
 
-		let has_voted = match self.voter_set_state.has_voted() {
+		let has_voted = match self.voter_set_state.has_voted(round) {
 			HasVoted::Yes(id, vote) => {
 				if local_key.as_ref().map(|k| k.public() == id).unwrap_or(false) {
 					HasVoted::Yes(id, vote)
@@ -541,7 +601,7 @@ where
 		}
 	}
 
-	fn proposed(&self, _round: u64, propose: PrimaryPropose<Block>) -> Result<(), Self::Error> {
+	fn proposed(&self, round: u64, propose: PrimaryPropose<Block>) -> Result<(), Self::Error> {
 		let local_id = crate::is_voter(&self.voters, &self.config.keystore);
 
 		let local_id = match local_id {
@@ -550,23 +610,26 @@ where
 		};
 
 		self.update_voter_set_state(|voter_set_state| {
-			let completed_rounds = match voter_set_state {
-				VoterSetState::Live { completed_rounds, current_round: HasVoted::No } => completed_rounds,
-				VoterSetState::Live { current_round, .. } if !current_round.can_propose() => {
-					// we've already proposed in this round (in a previous run),
-					// ignore the given vote and don't update the voter set
-					// state
-					return Ok(None);
-				},
-				_ => {
-					let msg = "Voter proposing after prevote/precommit or while paused.";
-					return Err(Error::Safety(msg.to_string()));
-				},
-			};
+			let (completed_rounds, current_rounds) = voter_set_state.with_current_round(round)?;
+			let current_round = current_rounds.get(&round)
+				.expect("checked in with_current_round that key exists; qed.");
+
+			if !current_round.can_propose() {
+				// we've already proposed in this round (in a previous run),
+				// ignore the given vote and don't update the voter set
+				// state
+				return Ok(None);
+			}
+
+			let mut current_rounds = current_rounds.clone();
+			let current_round = current_rounds.get_mut(&round)
+				.expect("checked previously that key exists; qed.");
+
+			*current_round = HasVoted::Yes(local_id, Vote::Propose(propose));
 
 			let set_state = VoterSetState::<Block>::Live {
 				completed_rounds: completed_rounds.clone(),
-				current_round: HasVoted::Yes(local_id, Vote::Propose(propose)),
+				current_rounds,
 			};
 
 			#[allow(deprecated)]
@@ -578,7 +641,7 @@ where
 		Ok(())
 	}
 
-	fn prevoted(&self, _round: u64, prevote: Prevote<Block>) -> Result<(), Self::Error> {
+	fn prevoted(&self, round: u64, prevote: Prevote<Block>) -> Result<(), Self::Error> {
 		let local_id = crate::is_voter(&self.voters, &self.config.keystore);
 
 		let local_id = match local_id {
@@ -587,26 +650,28 @@ where
 		};
 
 		self.update_voter_set_state(|voter_set_state| {
-			let (completed_rounds, propose) = match voter_set_state {
-				VoterSetState::Live { completed_rounds, current_round: HasVoted::No } =>
-					(completed_rounds, None),
-				VoterSetState::Live { completed_rounds, current_round: HasVoted::Yes(_, Vote::Propose(propose)) } =>
-					(completed_rounds, Some(propose)),
-				VoterSetState::Live { current_round, .. } if !current_round.can_prevote() => {
-					// we've already prevoted in this round (in a previous run),
-					// ignore the given vote and don't update the voter set
-					// state
-					return Ok(None);
-				},
-				_ => {
-					let msg = "Voter prevoting after precommit or while paused.";
-					return Err(Error::Safety(msg.to_string()));
-				},
-			};
+			let (completed_rounds, current_rounds) = voter_set_state.with_current_round(round)?;
+			let current_round = current_rounds.get(&round)
+				.expect("checked in with_current_round that key exists; qed.");
+
+			if !current_round.can_prevote() {
+				// we've already prevoted in this round (in a previous run),
+				// ignore the given vote and don't update the voter set
+				// state
+				return Ok(None);
+			}
+
+			let propose = current_round.propose();
+
+			let mut current_rounds = current_rounds.clone();
+			let current_round = current_rounds.get_mut(&round)
+				.expect("checked previously that key exists; qed.");
+
+			*current_round = HasVoted::Yes(local_id, Vote::Prevote(propose.cloned(), prevote));
 
 			let set_state = VoterSetState::<Block>::Live {
 				completed_rounds: completed_rounds.clone(),
-				current_round: HasVoted::Yes(local_id, Vote::Prevote(propose.cloned(), prevote)),
+				current_rounds,
 			};
 
 			#[allow(deprecated)]
@@ -618,7 +683,7 @@ where
 		Ok(())
 	}
 
-	fn precommitted(&self, _round: u64, precommit: Precommit<Block>) -> Result<(), Self::Error> {
+	fn precommitted(&self, round: u64, precommit: Precommit<Block>) -> Result<(), Self::Error> {
 		let local_id = crate::is_voter(&self.voters, &self.config.keystore);
 
 		let local_id = match local_id {
@@ -627,24 +692,38 @@ where
 		};
 
 		self.update_voter_set_state(|voter_set_state| {
-			let (completed_rounds, propose, prevote) = match voter_set_state {
-				VoterSetState::Live { completed_rounds, current_round: HasVoted::Yes(_, Vote::Prevote(propose, prevote)) } =>
-					(completed_rounds, propose, prevote),
-				VoterSetState::Live { current_round, .. } if !current_round.can_precommit() => {
-					// we've already precommitted in this round (in a previous run),
-					// ignore the given vote and don't update the voter set
-					// state
-					return Ok(None);
-				},
+			let (completed_rounds, current_rounds) = voter_set_state.with_current_round(round)?;
+			let current_round = current_rounds.get(&round)
+				.expect("checked in with_current_round that key exists; qed.");
+
+			if !current_round.can_precommit() {
+				// we've already precommitted in this round (in a previous run),
+				// ignore the given vote and don't update the voter set
+				// state
+				return Ok(None);
+			}
+
+			let propose = current_round.propose();
+			let prevote = match current_round {
+				HasVoted::Yes(_, Vote::Prevote(_, prevote)) => prevote,
 				_ => {
-					let msg = "Voter precommitting while paused.";
+					let msg = "Voter precommitting before prevoting.";
 					return Err(Error::Safety(msg.to_string()));
-				}
+				},
 			};
 
+			let mut current_rounds = current_rounds.clone();
+			let current_round = current_rounds.get_mut(&round)
+				.expect("checked previously that key exists; qed.");
+
+			*current_round = HasVoted::Yes(
+				local_id,
+				Vote::Precommit(propose.cloned(), prevote.clone(), precommit),
+			);
+
 			let set_state = VoterSetState::<Block>::Live {
 				completed_rounds: completed_rounds.clone(),
-				current_round: HasVoted::Yes(local_id, Vote::Precommit(propose.clone(), prevote.clone(), precommit)),
+				current_rounds,
 			};
 
 			#[allow(deprecated)]
@@ -673,25 +752,37 @@ where
 		);
 
 		self.update_voter_set_state(|voter_set_state| {
-			let mut completed_rounds = voter_set_state.completed_rounds();
+			// NOTE: we don't use `with_current_round` here, it is possible that
+			// we are not currently tracking this round if it is a round we
+			// caught up to.
+			let (completed_rounds, current_rounds) =
+				if let VoterSetState::Live { completed_rounds, current_rounds } = voter_set_state {
+					(completed_rounds, current_rounds)
+				} else {
+					let msg = "Voter acting while in paused state.";
+					return Err(Error::Safety(msg.to_string()));
+				};
+
+			let mut completed_rounds = completed_rounds.clone();
 
 			// TODO: Future integration will store the prevote and precommit index. See #2611.
 			let votes = historical_votes.seen().clone();
 
-			// NOTE: the Environment assumes that rounds are *always* completed in-order.
-			if !completed_rounds.push(CompletedRound {
+			completed_rounds.push(CompletedRound {
 				number: round,
 				state: state.clone(),
 				base,
 				votes,
-			}) {
-				let msg = "Voter completed round that is older than the last completed round.";
-				return Err(Error::Safety(msg.to_string()));
-			};
+			});
+
+			// remove the round from live rounds and start tracking the next round
+			let mut current_rounds = current_rounds.clone();
+			current_rounds.remove(&round);
+			current_rounds.insert(round + 1, HasVoted::No);
 
 			let set_state = VoterSetState::<Block>::Live {
 				completed_rounds,
-				current_round: HasVoted::No,
+				current_rounds,
 			};
 
 			#[allow(deprecated)]

substrate/core/finality-grandpa/src/lib.rs

@@ -75,7 +75,7 @@ use serde_json;
 use srml_finality_tracker;
 
 use grandpa::Error as GrandpaError;
-use grandpa::{voter, round::State as RoundState, BlockNumberOps, voter_set::VoterSet};
+use grandpa::{voter, BlockNumberOps, voter_set::VoterSet};
 
 use std::fmt;
 use std::sync::Arc;
@@ -103,7 +103,7 @@ pub use light_import::light_block_import;
 pub use observer::run_grandpa_observer;
 
 use aux_schema::PersistentData;
-use environment::{CompletedRound, CompletedRounds, Environment, HasVoted, SharedVoterSetState, VoterSetState};
+use environment::{Environment, SharedVoterSetState, VoterSetState};
 use import::GrandpaBlockImport;
 use until_imported::UntilGlobalMessageBlocksImported;
 use communication::NetworkBridge;
@@ -635,22 +635,11 @@ pub fn run_grandpa_voter<B, E, Block: BlockT<Hash=H256>, N, RA, SC, X>(
 
 					// start the new authority set using the block where the
 					// set changed (not where the signal happened!) as the base.
-					let genesis_state = RoundState::genesis((new.canon_hash, new.canon_number));
-
-					let set_state = VoterSetState::Live {
-						// always start at round 0 when changing sets.
-						completed_rounds: CompletedRounds::new(
-							CompletedRound {
-								number: 0,
-								state: genesis_state,
-								base: (new.canon_hash, new.canon_number),
-								votes: Vec::new(),
-							},
-							new.set_id,
-							&*authority_set.inner().read(),
-						),
-						current_round: HasVoted::No,
-					};
+					let set_state = VoterSetState::live(
+						new.set_id,
+						&*authority_set.inner().read(),
+						(new.canon_hash, new.canon_number),
+					);
 
 					#[allow(deprecated)]
 					aux_schema::write_voter_set_state(&**client.backend(), &set_state)?;
@@ -763,4 +752,4 @@ fn is_voter(
 			.find_map(|(p, _)| keystore.read().key_pair::<AuthorityPair>(&p).ok()),
 		None => None,
 	}
-}
+}

substrate/core/finality-grandpa/src/observer.rs

@@ -20,7 +20,7 @@ use futures::prelude::*;
 use futures::future::{self, Loop as FutureLoop};
 
 use grandpa::{
-	BlockNumberOps, Error as GrandpaError, round::State as RoundState, voter, voter_set::VoterSet
+	BlockNumberOps, Error as GrandpaError, voter, voter_set::VoterSet
 };
 use log::{debug, info, warn};
 
@@ -36,7 +36,6 @@ use crate::{
 use crate::authorities::SharedAuthoritySet;
 use crate::communication::NetworkBridge;
 use crate::consensus_changes::SharedConsensusChanges;
-use crate::environment::{CompletedRound, CompletedRounds, HasVoted};
 use fg_primitives::AuthorityId;
 
 struct ObserverChain<'a, Block: BlockT, B, E, RA>(&'a Client<B, E, Block, RA>);
@@ -238,22 +237,11 @@ pub fn run_grandpa_observer<B, E, Block: BlockT<Hash=H256>, N, RA, SC>(
 				VoterCommand::ChangeAuthorities(new) => {
 					// start the new authority set using the block where the
 					// set changed (not where the signal happened!) as the base.
-					let genesis_state = RoundState::genesis((new.canon_hash, new.canon_number));
-
-					let set_state = VoterSetState::Live::<Block> {
-						// always start at round 0 when changing sets.
-						completed_rounds: CompletedRounds::new(
-							CompletedRound {
-								number: 0,
-								state: genesis_state,
-								base: (new.canon_hash, new.canon_number),
-								votes: Vec::new(),
-							},
-							new.set_id,
-							&*authority_set.inner().read(),
-						),
-						current_round: HasVoted::No,
-					};
+					let set_state = VoterSetState::live(
+						new.set_id,
+						&*authority_set.inner().read(),
+						(new.canon_hash, new.canon_number),
+					);
 
 					#[allow(deprecated)]
 					crate::aux_schema::write_voter_set_state(&**client.backend(), &set_state)?;

substrate/core/finality-grandpa/src/tests.rs

@@ -17,6 +17,7 @@
 //! Tests and test helpers for GRANDPA.
 
 use super::*;
+use environment::HasVoted;
 use network::test::{Block, DummySpecialization, Hash, TestNetFactory, Peer, PeersClient};
 use network::test::{PassThroughVerifier};
 use network::config::{ProtocolConfig, Roles, BoxFinalityProofRequestBuilder};