Fix BABE epochs-transition logic on the core side

core/client/src/client.rs

@@ -1482,6 +1482,9 @@ impl<B, E, Block, RA> CallRuntimeAt<Block> for Client<B, E, Block, RA> where
 	}
 }
 
+/// NOTE: only use this implementation when you are sure there are NO consensus-level BlockImport
+/// objects. Otherwise, importing blocks directly into the client would be bypassing
+/// important verification work.
 impl<'a, B, E, Block, RA> consensus::BlockImport<Block> for &'a Client<B, E, Block, RA> where
 	B: backend::Backend<Block, Blake2Hasher>,
 	E: CallExecutor<Block, Blake2Hasher> + Clone + Send + Sync,
@@ -1491,6 +1494,13 @@ impl<'a, B, E, Block, RA> consensus::BlockImport<Block> for &'a Client<B, E, Blo
 
 	/// Import a checked and validated block. If a justification is provided in
 	/// `BlockImportParams` then `finalized` *must* be true.
+	///
+	/// NOTE: only use this implementation when there are NO consensus-level BlockImport
+	/// objects. Otherwise, importing blocks directly into the client would be bypassing
+	/// important verification work.
+	///
+	/// If you are not sure that there are no BlockImport objects provided by the consensus
+	/// algorithm, don't use this function.
 	fn import_block(
 		&mut self,
 		import_block: BlockImportParams<Block>,
@@ -1899,25 +1909,27 @@ where
 /// Utility methods for the client.
 pub mod utils {
 	use super::*;
-	use crate::{backend::Backend, blockchain, error};
+	use crate::{blockchain, error};
 	use primitives::H256;
+	use std::borrow::Borrow;
 
 	/// Returns a function for checking block ancestry, the returned function will
 	/// return `true` if the given hash (second parameter) is a descendent of the
 	/// base (first parameter). If the `current` parameter is defined, it should
 	/// represent the current block `hash` and its `parent hash`, if given the
 	/// function that's returned will assume that `hash` isn't part of the local DB
 	/// yet, and all searches in the DB will instead reference the parent.
-	pub fn is_descendent_of<'a, B, E, Block: BlockT<Hash=H256>, RA>(
-		client: &'a Client<B, E, Block, RA>,
-		current: Option<(&'a H256, &'a H256)>,
+	pub fn is_descendent_of<'a, Block: BlockT<Hash=H256>, T, H: Borrow<H256> + 'a>(
+		client: &'a T,
+		current: Option<(H, H)>,
 	) -> impl Fn(&H256, &H256) -> Result<bool, error::Error> + 'a
-		where B: Backend<Block, Blake2Hasher>,
-			  E: CallExecutor<Block, Blake2Hasher> + Send + Sync,
+		where T: ChainHeaderBackend<Block>,
 	{
 		move |base, hash| {
 			if base == hash { return Ok(false); }
 
+			let current = current.as_ref().map(|(c, p)| (c.borrow(), p.borrow()));
+
 			let mut hash = hash;
 			if let Some((current_hash, current_parent_hash)) = current {
 				if base == current_hash { return Ok(false); }
@@ -1931,7 +1943,7 @@ pub mod utils {
 			}
 
 			let tree_route = blockchain::tree_route(
-				|id| client.header(&id)?.ok_or_else(|| Error::UnknownBlock(format!("{:?}", id))),
+				|id| client.header(id)?.ok_or_else(|| Error::UnknownBlock(format!("{:?}", id))),
 				BlockId::Hash(*hash),
 				BlockId::Hash(*base),
 			)?;

core/consensus/aura/src/lib.rs

@@ -217,8 +217,8 @@ impl<H, B, C, E, I, P, Error, SO> slots::SimpleSlotWorker<B> for AuraWorker<C, E
 		self.block_import.clone()
 	}
 
-	fn epoch_data(&self, block: &B::Hash) -> Result<Self::EpochData, consensus_common::Error> {
-		authorities(self.client.as_ref(), &BlockId::Hash(*block))
+	fn epoch_data(&self, header: &B::Header, _slot_number: u64) -> Result<Self::EpochData, consensus_common::Error> {
+		authorities(self.client.as_ref(), &BlockId::Hash(header.hash()))
 	}
 
 	fn authorities_len(&self, epoch_data: &Self::EpochData) -> usize {
@@ -740,7 +740,7 @@ mod tests {
 			}
 		}
 
-		fn make_verifier(&self, client: PeersClient, _cfg: &ProtocolConfig)
+		fn make_verifier(&self, client: PeersClient, _cfg: &ProtocolConfig, _peer_data: &())
 			-> Self::Verifier
 		{
 			match client {

core/consensus/babe/primitives/src/digest.rs

@@ -79,6 +79,15 @@ impl BabePreDigest {
 			BabePreDigest::Secondary { slot_number, .. } => *slot_number,
 		}
 	}
+
+	/// Returns the weight _added_ by this digest, not the cumulative weight
+	/// of the chain.
+	pub fn added_weight(&self) -> crate::BabeBlockWeight {
+		match self {
+			BabePreDigest::Primary { .. } => 1,
+			BabePreDigest::Secondary { .. } => 0,
+		}
+	}
 }
 
 /// The prefix used by BABE for its VRF keys.
@@ -103,6 +112,11 @@ pub enum RawBabePreDigest {
 	#[codec(index = "2")]
 	Secondary {
 		/// Authority index
+		///
+		/// This is not strictly-speaking necessary, since the secondary slots
+		/// are assigned based on slot number and epoch randomness. But including
+		/// it makes things easier for higher-level users of the chain data to
+		/// be aware of the author of a secondary-slot block.
 		authority_index: AuthorityIndex,
 		/// Slot number
 		slot_number: SlotNumber,

core/consensus/babe/primitives/src/lib.rs

@@ -85,7 +85,7 @@ pub struct Epoch {
 	/// The epoch index
 	pub epoch_index: u64,
 	/// The starting slot of the epoch,
-	pub start_slot: u64,
+	pub start_slot: SlotNumber,
 	/// The duration of this epoch
 	pub duration: SlotNumber,
 	/// The authorities and their weights
@@ -94,6 +94,19 @@ pub struct Epoch {
 	pub randomness: [u8; VRF_OUTPUT_LENGTH],
 }
 
+impl Epoch {
+	/// "increment" the epoch, with given descriptor for the next.
+	pub fn increment(&self, descriptor: NextEpochDescriptor) -> Epoch {
+		Epoch {
+			epoch_index: self.epoch_index + 1,
+			start_slot: self.start_slot + self.duration,
+			duration: self.duration,
+			authorities: descriptor.authorities,
+			randomness: descriptor.randomness,
+		}
+	}
+}
+
 /// An consensus log item for BABE.
 #[derive(Decode, Encode, Clone, PartialEq, Eq)]
 pub enum ConsensusLog {
@@ -131,7 +144,7 @@ pub struct BabeConfiguration {
 	/// The authorities for the genesis epoch.
 	pub genesis_authorities: Vec<(AuthorityId, BabeAuthorityWeight)>,
 
-	/// The randomness for this epoch.
+	/// The randomness for the genesis epoch.
 	pub randomness: [u8; VRF_OUTPUT_LENGTH],
 
 	/// Whether this chain should run with secondary slots, which are assigned
@@ -145,7 +158,7 @@ impl slots::SlotData for BabeConfiguration {
 		self.slot_duration
 	}
 
-	const SLOT_KEY: &'static [u8] = b"babe_bootstrap_data";
+	const SLOT_KEY: &'static [u8] = b"babe_configuration";
 }
 
 decl_runtime_apis! {

core/consensus/babe/src/aux_schema.rs

@@ -22,11 +22,16 @@ use codec::{Decode, Encode};
 use client::backend::AuxStore;
 use client::error::{Result as ClientResult, Error as ClientError};
 use sr_primitives::traits::Block as BlockT;
+use babe_primitives::BabeBlockWeight;
 
 use super::{EpochChanges, SharedEpochChanges};
 
 const BABE_EPOCH_CHANGES: &[u8] = b"babe_epoch_changes";
 
+fn block_weight_key<H: Encode>(block_hash: H) -> Vec<u8> {
+	(b"block_weight", block_hash).encode()
+}
+
 fn load_decode<B, T>(backend: &B, key: &[u8]) -> ClientResult<Option<T>>
 	where
 		B: AuxStore,
@@ -69,3 +74,28 @@ pub(crate) fn write_epoch_changes<Block: BlockT, F, R>(
 		&[(BABE_EPOCH_CHANGES, encoded_epoch_changes.as_slice())],
 	)
 }
+
+/// Write the cumulative chain-weight of a block ot aux storage.
+pub(crate) fn write_block_weight<H: Encode, F, R>(
+	block_hash: H,
+	block_weight: &BabeBlockWeight,
+	write_aux: F,
+) -> R where
+	F: FnOnce(&[(Vec<u8>, &[u8])]) -> R,
+{
+
+	let key = block_weight_key(block_hash);
+	block_weight.using_encoded(|s|
+		write_aux(
+			&[(key, s)],
+		)
+	)
+}
+
+/// Load the cumulative chain-weight associated with a block.
+pub(crate) fn load_block_weight<H: Encode, B: AuxStore>(
+	backend: &B,
+	block_hash: H,
+) -> ClientResult<Option<BabeBlockWeight>> {
+	load_decode(backend, block_weight_key(block_hash).as_slice())
+}