beacon, yamltests: pass all final updates test

beacon/src/executive/transition/per_epoch/finalize.rs

+use crate::types::*;
+use crate::{Config, BeaconState, Error};
+use bm_le::{MaxVec, Compact, tree_root};
+use core::cmp::min;
+
+impl<C: Config> BeaconState<C> {
+	/// Process final updates
+	pub fn process_final_updates(&mut self) -> Result<(), Error> {
+		let current_epoch = self.current_epoch();
+		let next_epoch = current_epoch + 1;
+
+		// Reset eth1 data votes
+		if (self.slot + 1) % C::slots_per_eth1_voting_period() == 0 {
+			self.eth1_data_votes = Default::default();
+		}
+
+		// Update effective balances with hysteresis
+		for index in 0..(self.validators.len() as u64) {
+			let validator = &mut self.validators[index as usize];
+			let balance = self.balances[index as usize];
+			let half_increment = C::effective_balance_increment() / 2;
+			if balance < validator.effective_balance ||
+				validator.effective_balance + 3 * half_increment < balance
+			{
+				validator.effective_balance = min(
+					balance - balance % C::effective_balance_increment(),
+					C::max_effective_balance()
+				);
+			}
+		}
+
+		// Update start shard
+		self.start_shard =
+			(self.start_shard + self.shard_delta(current_epoch)) %
+			C::shard_count();
+
+		// Set active index root
+		let index_epoch = next_epoch + C::activation_exit_delay();
+		let index_root_position = index_epoch % C::epochs_per_historical_vector();
+		self.active_index_roots[index_root_position as usize] =
+			tree_root::<C::Digest, _>(
+				&Compact(MaxVec::<_, C::ValidatorRegistryLimit>::from(self.active_validator_indices(
+					next_epoch + C::activation_exit_delay()
+				)))
+			);
+
+		// Set committees root
+		let committee_root_position = next_epoch % C::epochs_per_historical_vector();
+		self.compact_committees_roots[committee_root_position as usize] =
+			self.compact_committees_root(next_epoch)?;
+
+		// Set total slashed balances
+		self.slashings[
+			(next_epoch % C::epochs_per_slashings_vector()) as usize
+		] = 0;
+
+		// Set randao mix
+		self.randao_mixes[
+			(next_epoch % C::epochs_per_historical_vector()) as usize
+		] = self.randao_mix(current_epoch);
+
+		// Set historical root accumulator
+		if next_epoch %
+			(C::slots_per_historical_root() / C::slots_per_epoch())
+			== 0
+		{
+			self.historical_roots.push(tree_root::<C::Digest, _>(&HistoricalBatch::<C> {
+				block_roots: self.block_roots.clone(),
+				state_roots: self.state_roots.clone(),
+			}));
+		}
+
+		// Rotate current/previous epoch attestations
+		self.previous_epoch_attestations =
+			self.current_epoch_attestations.clone();
+		self.current_epoch_attestations = Default::default();
+
+		Ok(())
+	}
+}

beacon/src/executive/transition/per_epoch/mod.rs

@@ -4,3 +4,4 @@ mod crosslink;
 mod reward;
 mod registry;
 mod slashing;
+mod finalize;

yamltests/transitiontests/src/epoch_processing.rs

@@ -65,3 +65,19 @@ impl<C: Config> Test for SlashingsTest<C> {
 		});
 	}
 }
+
+#[derive(Serialize, Deserialize, Debug)]
+#[serde(deny_unknown_fields)]
+pub struct FinalUpdatesTest<C: Config> {
+	pub description: String,
+	pub pre: BeaconState<C>,
+	pub post: Option<BeaconState<C>>,
+}
+
+impl<C: Config> Test for FinalUpdatesTest<C> {
+	fn run(&self) {
+		run_test_with(&self.description, &self.pre, self.post.as_ref(), |state| {
+			state.process_final_updates()
+		});
+	}
+}

yamltests/transitiontests/src/main.rs

@@ -49,6 +49,7 @@ fn run_all<C: Config + serde::Serialize + DeserializeOwned>(runner: &str, file:
 		"crosslinks" => run::<CrosslinksTest<C>>(file),
 		"registry_updates" => run::<RegistryUpdatesTest<C>>(file),
 		"slashings" => run::<SlashingsTest<C>>(file),
+		"final_updates" => run::<FinalUpdatesTest<C>>(file),
 		// "blocks" => run::<BlocksTest, _>(file, &config),
 		// "slots" => run::<SlotsTest, _>(file, &config),
 		_ => panic!("Unsupported runner"),