babe: support online configuration upgrades

bin/node/runtime/src/lib.rs

@@ -127,7 +127,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	// and set impl_version to 0. If only runtime
 	// implementation changes and behavior does not, then leave spec_version as
 	// is and increment impl_version.
-	spec_version: 243,
+	spec_version: 244,
 	impl_version: 0,
 	apis: RUNTIME_API_VERSIONS,
 	transaction_version: 1,
@@ -789,13 +789,13 @@ impl_runtime_apis! {
 	}
 
 	impl sp_consensus_babe::BabeApi<Block> for Runtime {
-		fn configuration() -> sp_consensus_babe::BabeConfiguration {
+		fn configuration() -> sp_consensus_babe::BabeGenesisConfiguration {
 			// The choice of `c` parameter (where `1 - c` represents the
 			// probability of a slot being empty), is done in accordance to the
 			// slot duration and expected target block time, for safely
 			// resisting network delays of maximum two seconds.
 			// <https://research.web3.foundation/en/latest/polkadot/BABE/Babe/#6-practical-results>
-			sp_consensus_babe::BabeConfiguration {
+			sp_consensus_babe::BabeGenesisConfiguration {
 				slot_duration: Babe::slot_duration(),
 				epoch_length: EpochDuration::get(),
 				c: PRIMARY_PROBABILITY,

client/consensus/babe/rpc/src/lib.rs

@@ -118,7 +118,7 @@ impl<B, C, SC> BabeApi for BabeRPCHandler<B, C, SC>
 
 			for slot_number in epoch_start..epoch_end {
 				let epoch = epoch_data(&shared_epoch, &client, &babe_config, slot_number, &select_chain)?;
-				if let Some((claim, key)) = authorship::claim_slot(slot_number, &epoch, &babe_config, &keystore) {
+				if let Some((claim, key)) = authorship::claim_slot(slot_number, &epoch, &keystore) {
 					match claim {
 						PreDigest::Primary { .. } => {
 							claims.entry(key.public()).or_default().primary.push(slot_number);
@@ -184,7 +184,7 @@ fn epoch_data<B, C, SC>(
 		&parent.hash(),
 		parent.number().clone(),
 		slot_number,
-		|slot| babe_config.genesis_epoch(slot),
+		|slot| Epoch::genesis(&babe_config, slot),
 	)
 		.map_err(|e| Error::Consensus(ConsensusError::ChainLookup(format!("{:?}", e))))?
 		.ok_or(Error::Consensus(ConsensusError::InvalidAuthoritiesSet))

client/consensus/babe/src/authorship.rs

@@ -19,7 +19,7 @@
 use merlin::Transcript;
 use sp_consensus_babe::{
 	AuthorityId, BabeAuthorityWeight, BABE_ENGINE_ID, BABE_VRF_PREFIX,
-	SlotNumber, AuthorityPair, BabeConfiguration
+	SlotNumber, AuthorityPair,
 };
 use sp_consensus_babe::digests::{PreDigest, PrimaryPreDigest, SecondaryPreDigest};
 use sp_consensus_vrf::schnorrkel::{VRFOutput, VRFProof};
@@ -147,12 +147,11 @@ fn claim_secondary_slot(
 pub fn claim_slot(
 	slot_number: SlotNumber,
 	epoch: &Epoch,
-	config: &BabeConfiguration,
 	keystore: &KeyStorePtr,
 ) -> Option<(PreDigest, AuthorityPair)> {
-	claim_primary_slot(slot_number, epoch, config.c, keystore)
+	claim_primary_slot(slot_number, epoch, epoch.config.c, keystore)
 		.or_else(|| {
-			if config.secondary_slots {
+			if epoch.config.secondary_slots {
 				claim_secondary_slot(
 					slot_number,
 					&epoch.authorities,

client/consensus/babe/src/aux_schema.rs

@@ -24,13 +24,13 @@ use codec::{Decode, Encode};
 use sc_client_api::backend::AuxStore;
 use sp_blockchain::{Result as ClientResult, Error as ClientError};
 use sp_runtime::traits::Block as BlockT;
-use sp_consensus_babe::BabeBlockWeight;
+use sp_consensus_babe::{BabeBlockWeight, BabeGenesisConfiguration};
 use sc_consensus_epochs::{EpochChangesFor, SharedEpochChanges, migration::EpochChangesForV0};
-use crate::Epoch;
+use crate::{Epoch, migration::EpochV0};
 
 const BABE_EPOCH_CHANGES_VERSION: &[u8] = b"babe_epoch_changes_version";
 const BABE_EPOCH_CHANGES_KEY: &[u8] = b"babe_epoch_changes";
-const BABE_EPOCH_CHANGES_CURRENT_VERSION: u32 = 1;
+const BABE_EPOCH_CHANGES_CURRENT_VERSION: u32 = 2;
 
 fn block_weight_key<H: Encode>(block_hash: H) -> Vec<u8> {
 	(b"block_weight", block_hash).encode()
@@ -53,14 +53,19 @@ fn load_decode<B, T>(backend: &B, key: &[u8]) -> ClientResult<Option<T>>
 /// Load or initialize persistent epoch change data from backend.
 pub(crate) fn load_epoch_changes<Block: BlockT, B: AuxStore>(
 	backend: &B,
+	config: &BabeGenesisConfiguration,
 ) -> ClientResult<SharedEpochChanges<Block, Epoch>> {
 	let version = load_decode::<_, u32>(backend, BABE_EPOCH_CHANGES_VERSION)?;
 
 	let maybe_epoch_changes = match version {
-		None => load_decode::<_, EpochChangesForV0<Block, Epoch>>(
+		None => load_decode::<_, EpochChangesForV0<Block, EpochV0>>(
 			backend,
 			BABE_EPOCH_CHANGES_KEY,
-		)?.map(|v0| v0.migrate()),
+		)?.map(|v0| v0.migrate().map(|_, _, epoch| epoch.migrate(config))),
+		Some(1) => load_decode::<_, EpochChangesFor<Block, EpochV0>>(
+			backend,
+			BABE_EPOCH_CHANGES_KEY,
+		)?.map(|v1| v1.map(|_, _, epoch| epoch.migrate(config))),
 		Some(BABE_EPOCH_CHANGES_CURRENT_VERSION) => load_decode::<_, EpochChangesFor<Block, Epoch>>(
 			backend,
 			BABE_EPOCH_CHANGES_KEY,
@@ -131,18 +136,19 @@ pub(crate) fn load_block_weight<H: Encode, B: AuxStore>(
 #[cfg(test)]
 mod test {
 	use super::*;
-	use crate::Epoch;
+	use crate::migration::EpochV0;
 	use fork_tree::ForkTree;
 	use substrate_test_runtime_client;
 	use sp_core::H256;
 	use sp_runtime::traits::NumberFor;
+	use sp_consensus_babe::BabeGenesisConfiguration;
 	use sc_consensus_epochs::{PersistedEpoch, PersistedEpochHeader, EpochHeader};
 	use sp_consensus::Error as ConsensusError;
 	use sc_network_test::Block as TestBlock;
 
 	#[test]
 	fn load_decode_from_v0_epoch_changes() {
-		let epoch = Epoch {
+		let epoch = EpochV0 {
 			start_slot: 0,
 			authorities: vec![],
 			randomness: [0; 32],
@@ -160,7 +166,7 @@ mod test {
 
 		client.insert_aux(
 			&[(BABE_EPOCH_CHANGES_KEY,
-			   &EpochChangesForV0::<TestBlock, Epoch>::from_raw(v0_tree).encode()[..])],
+			   &EpochChangesForV0::<TestBlock, EpochV0>::from_raw(v0_tree).encode()[..])],
 			&[],
 		).unwrap();
 
@@ -169,7 +175,16 @@ mod test {
 			None,
 		);
 
-		let epoch_changes = load_epoch_changes::<TestBlock, _>(&client).unwrap();
+		let epoch_changes = load_epoch_changes::<TestBlock, _>(
+			&client, &BabeGenesisConfiguration {
+				slot_duration: 10,
+				epoch_length: 4,
+				c: (3, 10),
+				genesis_authorities: Vec::new(),
+				randomness: Default::default(),
+				secondary_slots: true,
+			},
+		).unwrap();
 
 		assert!(
 			epoch_changes.lock()
@@ -192,7 +207,7 @@ mod test {
 
 		assert_eq!(
 			load_decode::<_, u32>(&client, BABE_EPOCH_CHANGES_VERSION).unwrap(),
-			Some(1),
+			Some(2),
 		);
 	}
 }