Merge branch 'master' into network-server

beacon_node/beacon_chain/src/beacon_chain.rs

@@ -82,7 +82,7 @@ where
         let state_root = genesis_state.canonical_root();
         state_store.put(&state_root, &ssz_encode(&genesis_state)[..])?;
 
-        let block_root = genesis_block.into_header().canonical_root();
+        let block_root = genesis_block.block_header().canonical_root();
         block_store.put(&block_root, &ssz_encode(&genesis_block)[..])?;
 
         let finalized_head = RwLock::new(CheckPoint::new(
@@ -189,7 +189,7 @@ where
     pub fn advance_state(&self, slot: Slot) -> Result<(), SlotProcessingError> {
         let state_slot = self.state.read().slot;
 
-        let latest_block_header = self.head().beacon_block.into_header();
+        let latest_block_header = self.head().beacon_block.block_header();
 
         for _ in state_slot.as_u64()..slot.as_u64() {
             per_slot_processing(&mut *self.state.write(), &latest_block_header, &self.spec)?;
@@ -561,7 +561,7 @@ where
     pub fn process_block(&self, block: BeaconBlock) -> Result<BlockProcessingOutcome, Error> {
         debug!("Processing block with slot {}...", block.slot);
 
-        let block_root = block.into_header().canonical_root();
+        let block_root = block.block_header().canonical_root();
 
         let present_slot = self.present_slot();
 
@@ -596,8 +596,7 @@ where
 
         // Transition the parent state to the present slot.
         let mut state = parent_state;
-        println!("parent process state: {:?}", state.latest_block_header);
+        let previous_block_header = parent_block.block_header();
-        let previous_block_header = parent_block.into_header();
         for _ in state.slot.as_u64()..present_slot.as_u64() {
             if let Err(e) = per_slot_processing(&mut state, &previous_block_header, &self.spec) {
                 return Ok(BlockProcessingOutcome::InvalidBlock(
@@ -614,8 +613,6 @@ where
             ));
         }
 
-        println!("process state: {:?}", state.latest_block_header);
-
         let state_root = state.canonical_root();
 
         if block.state_root != state_root {
@@ -706,8 +703,6 @@ where
 
         per_block_processing_without_verifying_block_signature(&mut state, &block, &self.spec)?;
 
-        println!("produce state: {:?}", state.latest_block_header);
-
         let state_root = state.canonical_root();
 
         block.state_root = state_root;

beacon_node/beacon_chain/test_harness/specs/validator_registry.yaml

@@ -9,6 +9,7 @@ test_cases:
       deposits_for_chain_start: 1000
       num_slots: 64
       skip_slots: [2, 3]
+      persistent_committee_period: 0
       deposits:
           # At slot 1, create a new validator deposit of 5 ETH.
         - slot: 1

beacon_node/beacon_chain/test_harness/src/test_case.rs

@@ -62,6 +62,10 @@ impl TestCase {
             spec.slots_per_epoch = n;
         }
 
+        if let Some(n) = self.config.persistent_committee_period {
+            spec.persistent_committee_period = n;
+        }
+
         spec
     }
 

beacon_node/beacon_chain/test_harness/src/test_case/config.rs

@@ -20,6 +20,8 @@ pub struct Config {
     pub deposits_for_chain_start: usize,
     /// Number of slots in an epoch.
     pub slots_per_epoch: Option<u64>,
+    /// Affects the number of epochs a validator must be active before they can withdraw.
+    pub persistent_committee_period: Option<u64>,
     /// Number of slots to build before ending execution.
     pub num_slots: u64,
     /// Number of slots that should be skipped due to inactive validator.
@@ -45,6 +47,7 @@ impl Config {
             deposits_for_chain_start: as_usize(&yaml, "deposits_for_chain_start")
                 .expect("Must specify validator count"),
             slots_per_epoch: as_u64(&yaml, "slots_per_epoch"),
+            persistent_committee_period: as_u64(&yaml, "persistent_committee_period"),
             num_slots: as_u64(&yaml, "num_slots").expect("Must specify `config.num_slots`"),
             skip_slots: as_vec_u64(yaml, "skip_slots"),
             deposits: parse_deposits(&yaml),

eth2/fork_choice/src/bitwise_lmd_ghost.rs

@@ -10,10 +10,7 @@ use db::{
 use log::{debug, trace};
 use std::collections::HashMap;
 use std::sync::Arc;
-use types::{
+use types::{BeaconBlock, ChainSpec, Hash256, Slot, SlotHeight};
-    validator_registry::get_active_validator_indices, BeaconBlock, ChainSpec, Hash256, Slot,
-    SlotHeight,
-};
 
 //TODO: Pruning - Children
 //TODO: Handle Syncing
@@ -93,10 +90,8 @@ where
             .get_deserialized(&state_root)?
             .ok_or_else(|| ForkChoiceError::MissingBeaconState(*state_root))?;
 
-        let active_validator_indices = get_active_validator_indices(
+        let active_validator_indices =
-            &current_state.validator_registry[..],
+            current_state.get_active_validator_indices(block_slot.epoch(spec.slots_per_epoch));
-            block_slot.epoch(spec.slots_per_epoch),
-        );
 
         for index in active_validator_indices {
             let balance = std::cmp::min(

eth2/fork_choice/src/optimized_lmd_ghost.rs

@@ -10,10 +10,7 @@ use log::{debug, trace};
 use std::cmp::Ordering;
 use std::collections::HashMap;
 use std::sync::Arc;
-use types::{
+use types::{BeaconBlock, ChainSpec, Hash256, Slot, SlotHeight};
-    validator_registry::get_active_validator_indices, BeaconBlock, ChainSpec, Hash256, Slot,
-    SlotHeight,
-};
 
 //TODO: Pruning - Children
 //TODO: Handle Syncing
@@ -93,10 +90,8 @@ where
             .get_deserialized(&state_root)?
             .ok_or_else(|| ForkChoiceError::MissingBeaconState(*state_root))?;
 
-        let active_validator_indices = get_active_validator_indices(
+        let active_validator_indices =
-            &current_state.validator_registry[..],
+            current_state.get_active_validator_indices(block_slot.epoch(spec.slots_per_epoch));
-            block_slot.epoch(spec.slots_per_epoch),
-        );
 
         for index in active_validator_indices {
             let balance = std::cmp::min(

eth2/fork_choice/src/slow_lmd_ghost.rs

@@ -8,9 +8,7 @@ use db::{
 use log::{debug, trace};
 use std::collections::HashMap;
 use std::sync::Arc;
-use types::{
+use types::{BeaconBlock, ChainSpec, Hash256, Slot};
-    validator_registry::get_active_validator_indices, BeaconBlock, ChainSpec, Hash256, Slot,
-};
 
 //TODO: Pruning and syncing
 
@@ -61,10 +59,8 @@ where
             .get_deserialized(&state_root)?
             .ok_or_else(|| ForkChoiceError::MissingBeaconState(*state_root))?;
 
-        let active_validator_indices = get_active_validator_indices(
+        let active_validator_indices =
-            &current_state.validator_registry[..],
+            current_state.get_active_validator_indices(block_slot.epoch(spec.slots_per_epoch));
-            block_slot.epoch(spec.slots_per_epoch),
-        );
 
         for index in active_validator_indices {
             let balance = std::cmp::min(

eth2/fork_choice/tests/tests.rs

@@ -242,8 +242,9 @@ fn setup_inital_state(
 
     let spec = ChainSpec::foundation();
 
-    let state_builder =
+    let mut state_builder =
         TestingBeaconStateBuilder::from_single_keypair(num_validators, &Keypair::random(), &spec);
+    state_builder.build_caches(&spec).unwrap();
     let (state, _keypairs) = state_builder.build();
 
     let state_root = state.canonical_root();

eth2/state_processing/src/common/exit_validator.rs

@@ -0,0 +1,22 @@
+use types::{BeaconStateError as Error, *};
+
+/// Exit the validator of the given `index`.
+///
+/// Spec v0.5.0
+pub fn exit_validator(
+    state: &mut BeaconState,
+    validator_index: usize,
+    spec: &ChainSpec,
+) -> Result<(), Error> {
+    if validator_index >= state.validator_registry.len() {
+        return Err(Error::UnknownValidator);
+    }
+
+    let delayed_epoch = state.get_delayed_activation_exit_epoch(state.current_epoch(spec), spec);
+
+    if state.validator_registry[validator_index].exit_epoch > delayed_epoch {
+        state.validator_registry[validator_index].exit_epoch = delayed_epoch;
+    }
+
+    Ok(())
+}

eth2/state_processing/src/common/mod.rs

@@ -0,0 +1,7 @@
+mod exit_validator;
+mod slash_validator;
+mod verify_bitfield;
+
+pub use exit_validator::exit_validator;
+pub use slash_validator::slash_validator;
+pub use verify_bitfield::verify_bitfield_length;

eth2/state_processing/src/common/slash_validator.rs

@@ -0,0 +1,62 @@
+use crate::common::exit_validator;
+use types::{BeaconStateError as Error, *};
+
+/// Slash the validator with index ``index``.
+///
+/// Spec v0.5.0
+pub fn slash_validator(
+    state: &mut BeaconState,
+    validator_index: usize,
+    spec: &ChainSpec,
+) -> Result<(), Error> {
+    let current_epoch = state.current_epoch(spec);
+
+    if (validator_index >= state.validator_registry.len())
+        | (validator_index >= state.validator_balances.len())
+    {
+        return Err(BeaconStateError::UnknownValidator);
+    }
+
+    let validator = &state.validator_registry[validator_index];
+
+    let effective_balance = state.get_effective_balance(validator_index, spec)?;
+
+    // A validator that is withdrawn cannot be slashed.
+    //
+    // This constraint will be lifted in Phase 0.
+    if state.slot
+        >= validator
+            .withdrawable_epoch
+            .start_slot(spec.slots_per_epoch)
+    {
+        return Err(Error::ValidatorIsWithdrawable);
+    }
+
+    exit_validator(state, validator_index, spec)?;
+
+    state.set_slashed_balance(
+        current_epoch,
+        state.get_slashed_balance(current_epoch, spec)? + effective_balance,
+        spec,
+    )?;
+
+    let whistleblower_index =
+        state.get_beacon_proposer_index(state.slot, RelativeEpoch::Current, spec)?;
+    let whistleblower_reward = effective_balance / spec.whistleblower_reward_quotient;
+
+    safe_add_assign!(
+        state.validator_balances[whistleblower_index as usize],
+        whistleblower_reward
+    );
+    safe_sub_assign!(
+        state.validator_balances[validator_index],
+        whistleblower_reward
+    );
+
+    state.validator_registry[validator_index].slashed = true;
+
+    state.validator_registry[validator_index].withdrawable_epoch =
+        current_epoch + Epoch::from(spec.latest_slashed_exit_length);
+
+    Ok(())
+}

eth2/state_processing/src/common/verify_bitfield.rs

@@ -1,10 +1,10 @@
-use crate::*;
+use types::*;
 
 /// Verify ``bitfield`` against the ``committee_size``.
 ///
 /// Is title `verify_bitfield` in spec.
 ///
-/// Spec v0.4.0
+/// Spec v0.5.0
 pub fn verify_bitfield_length(bitfield: &Bitfield, committee_size: usize) -> bool {
     if bitfield.num_bytes() != ((committee_size + 7) / 8) {
         return false;

eth2/state_processing/src/get_genesis_state.rs

@@ -34,11 +34,10 @@ pub fn get_genesis_state(
 
     // Set all the active index roots to be the genesis active index root.
     let active_validator_indices = state
-        .get_active_validator_indices(spec.genesis_epoch, spec)?
+        .get_cached_active_validator_indices(RelativeEpoch::Current, spec)?
         .to_vec();
     let genesis_active_index_root = Hash256::from_slice(&active_validator_indices.hash_tree_root());
-    state.latest_active_index_roots =
+    state.fill_active_index_roots_with(genesis_active_index_root, spec);
-        vec![genesis_active_index_root; spec.latest_active_index_roots_length as usize];
 
     // Generate the current shuffling seed.
     state.current_shuffling_seed = state.generate_seed(spec.genesis_epoch, spec)?;

eth2/state_processing/src/lib.rs

@@ -1,6 +1,7 @@
 #[macro_use]
 mod macros;
 
+pub mod common;
 pub mod get_genesis_state;
 pub mod per_block_processing;
 pub mod per_epoch_processing;

eth2/state_processing/src/per_block_processing.rs

@@ -1,4 +1,5 @@
 use self::verify_proposer_slashing::verify_proposer_slashing;
+use crate::common::slash_validator;
 use errors::{BlockInvalid as Invalid, BlockProcessingError as Error, IntoWithIndex};
 use rayon::prelude::*;
 use ssz::{SignedRoot, TreeHash};
@@ -100,12 +101,15 @@ pub fn process_block_header(
 ) -> Result<(), Error> {
     verify!(block.slot == state.slot, Invalid::StateSlotMismatch);
 
+    // NOTE: this is not to spec. I think spec is broken. See:
+    //
+    // https://github.com/ethereum/eth2.0-specs/issues/797
     verify!(
-        block.previous_block_root.as_bytes() == &state.latest_block_header.hash_tree_root()[..],
+        block.previous_block_root == *state.get_block_root(state.slot - 1, spec)?,
         Invalid::ParentBlockRootMismatch
     );
 
-    state.latest_block_header = block.into_temporary_header(spec);
+    state.latest_block_header = block.temporary_block_header(spec);
 
     Ok(())
 }
@@ -219,7 +223,7 @@ pub fn process_proposer_slashings(
 
     // Update the state.
     for proposer_slashing in proposer_slashings {
-        state.slash_validator(proposer_slashing.proposer_index as usize, spec)?;
+        slash_validator(state, proposer_slashing.proposer_index as usize, spec)?;
     }
 
     Ok(())
@@ -276,7 +280,7 @@ pub fn process_attester_slashings(
             .map_err(|e| e.into_with_index(i))?;
 
         for i in slashable_indices {
-            state.slash_validator(i as usize, spec)?;
+            slash_validator(state, i as usize, spec)?;
         }
     }
 
@@ -384,7 +388,7 @@ pub fn process_deposits(
             // Create a new validator.
             let validator = Validator {
                 pubkey: deposit_input.pubkey.clone(),
-                withdrawal_credentials: deposit_input.withdrawal_credentials.clone(),
+                withdrawal_credentials: deposit_input.withdrawal_credentials,
                 activation_epoch: spec.far_future_epoch,
                 exit_epoch: spec.far_future_epoch,
                 withdrawable_epoch: spec.far_future_epoch,

eth2/state_processing/src/per_block_processing/validate_attestation.rs

@@ -1,6 +1,6 @@
 use super::errors::{AttestationInvalid as Invalid, AttestationValidationError as Error};
+use crate::common::verify_bitfield_length;
 use ssz::TreeHash;
-use types::beacon_state::helpers::*;
 use types::*;
 
 /// Indicates if an `Attestation` is valid to be included in a block in the current epoch of the
@@ -176,17 +176,7 @@ fn validate_attestation_signature_optional(
     );
 
     if verify_signature {
-        let attestation_epoch = attestation.data.slot.epoch(spec.slots_per_epoch);
+        verify_attestation_signature(state, committee, attestation, spec)?;
-        verify_attestation_signature(
-            state,
-            committee,
-            attestation_epoch,
-            &attestation.aggregation_bitfield,
-            &attestation.custody_bitfield,
-            &attestation.data,
-            &attestation.aggregate_signature,
-            spec,
-        )?;
     }
 
     // Crosslink data root is zero (to be removed in phase 1).
@@ -210,32 +200,29 @@ fn validate_attestation_signature_optional(
 fn verify_attestation_signature(
     state: &BeaconState,
     committee: &[usize],
-    attestation_epoch: Epoch,
+    a: &Attestation,
-    aggregation_bitfield: &Bitfield,
-    custody_bitfield: &Bitfield,
-    attestation_data: &AttestationData,
-    aggregate_signature: &AggregateSignature,
     spec: &ChainSpec,
 ) -> Result<(), Error> {
     let mut aggregate_pubs = vec![AggregatePublicKey::new(); 2];
     let mut message_exists = vec![false; 2];
+    let attestation_epoch = a.data.slot.epoch(spec.slots_per_epoch);
 
     for (i, v) in committee.iter().enumerate() {
-        let validator_signed = aggregation_bitfield.get(i).map_err(|_| {
+        let validator_signed = a.aggregation_bitfield.get(i).map_err(|_| {
             Error::Invalid(Invalid::BadAggregationBitfieldLength {
                 committee_len: committee.len(),
-                bitfield_len: aggregation_bitfield.len(),
+                bitfield_len: a.aggregation_bitfield.len(),
             })
         })?;
 
         if validator_signed {
-            let custody_bit: bool = match custody_bitfield.get(i) {
+            let custody_bit: bool = match a.custody_bitfield.get(i) {
                 Ok(bit) => bit,
                 // Invalidate signature if custody_bitfield.len() < committee
                 Err(_) => {
                     return Err(Error::Invalid(Invalid::BadCustodyBitfieldLength {
                         committee_len: committee.len(),
-                        bitfield_len: aggregation_bitfield.len(),
+                        bitfield_len: a.aggregation_bitfield.len(),
                     }));
                 }
             };
@@ -254,14 +241,14 @@ fn verify_attestation_signature(
 
     // Message when custody bitfield is `false`
     let message_0 = AttestationDataAndCustodyBit {
-        data: attestation_data.clone(),
+        data: a.data.clone(),
         custody_bit: false,
     }
     .hash_tree_root();
 
     // Message when custody bitfield is `true`
     let message_1 = AttestationDataAndCustodyBit {
-        data: attestation_data.clone(),
+        data: a.data.clone(),
         custody_bit: true,
     }
     .hash_tree_root();
@@ -283,7 +270,8 @@ fn verify_attestation_signature(
     let domain = spec.get_domain(attestation_epoch, Domain::Attestation, &state.fork);
 
     verify!(
-        aggregate_signature.verify_multiple(&messages[..], domain, &keys[..]),
+        a.aggregate_signature
+            .verify_multiple(&messages[..], domain, &keys[..]),
         Invalid::BadSignature
     );
 

eth2/state_processing/src/per_block_processing/verify_deposit.rs

@@ -71,9 +71,7 @@ pub fn get_existing_validator_index(
 ) -> Result<Option<u64>, Error> {
     let deposit_input = &deposit.deposit_data.deposit_input;
 
-    let validator_index = state
+    let validator_index = state.get_validator_index(&deposit_input.pubkey)?;
-        .get_validator_index(&deposit_input.pubkey)?
-        .and_then(|i| Some(i));
 
     match validator_index {
         None => Ok(None),

eth2/state_processing/src/per_block_processing/verify_slashable_attestation.rs

@@ -1,8 +1,8 @@
 use super::errors::{
     SlashableAttestationInvalid as Invalid, SlashableAttestationValidationError as Error,
 };
+use crate::common::verify_bitfield_length;
 use ssz::TreeHash;
-use types::beacon_state::helpers::verify_bitfield_length;
 use types::*;
 
 /// Indicates if a `SlashableAttestation` is valid to be included in a block in the current epoch of the given

eth2/state_processing/src/per_epoch_processing.rs

@@ -1,18 +1,24 @@
+use apply_rewards::apply_rewards;
 use errors::EpochProcessingError as Error;
-use integer_sqrt::IntegerSquareRoot;
+use process_ejections::process_ejections;
-use process_validator_registry::process_validator_registry;
+use process_exit_queue::process_exit_queue;
-use rayon::prelude::*;
+use process_slashings::process_slashings;
 use ssz::TreeHash;
 use std::collections::HashMap;
-use types::{validator_registry::get_active_validator_indices, *};
+use types::*;
+use update_registry_and_shuffling_data::update_registry_and_shuffling_data;
 use validator_statuses::{TotalBalances, ValidatorStatuses};
 use winning_root::{winning_root, WinningRoot};
 
+pub mod apply_rewards;
 pub mod errors;
 pub mod get_attestation_participants;
 pub mod inclusion_distance;
-pub mod process_validator_registry;
+pub mod process_ejections;
+pub mod process_exit_queue;
+pub mod process_slashings;
 pub mod tests;
+pub mod update_registry_and_shuffling_data;
 pub mod validator_statuses;
 pub mod winning_root;
 
@@ -26,34 +32,51 @@ pub type WinningRootHashSet = HashMap<u64, WinningRoot>;
 /// Mutates the given `BeaconState`, returning early if an error is encountered. If an error is
 /// returned, a state might be "half-processed" and therefore in an invalid state.
 ///
-/// Spec v0.4.0
+/// Spec v0.5.0
 pub fn per_epoch_processing(state: &mut BeaconState, spec: &ChainSpec) -> Result<(), Error> {
     // Ensure the previous and next epoch caches are built.
     state.build_epoch_cache(RelativeEpoch::Previous, spec)?;
     state.build_epoch_cache(RelativeEpoch::Current, spec)?;
 
-    let mut statuses = initialize_validator_statuses(&state, spec)?;
+    // Load the struct we use to assign validators into sets based on their participation.
+    //
+    // E.g., attestation in the previous epoch, attested to the head, etc.
+    let mut validator_statuses = ValidatorStatuses::new(state, spec)?;
+    validator_statuses.process_attestations(&state, spec)?;
 
-    process_eth1_data(state, spec);
+    // Justification.
+    update_justification_and_finalization(state, &validator_statuses.total_balances, spec)?;
 
-    process_justification(state, &statuses.total_balances, spec);
+    // Crosslinks.
-
-    // Crosslinks
     let winning_root_for_shards = process_crosslinks(state, spec)?;
 
-    // Rewards and Penalities
+    // Eth1 data.
-    process_rewards_and_penalities(state, &mut statuses, &winning_root_for_shards, spec)?;
+    maybe_reset_eth1_period(state, spec);
 
-    // Ejections
+    // Rewards and Penalities.
-    state.process_ejections(spec)?;
+    apply_rewards(
+        state,
+        &mut validator_statuses,
+        &winning_root_for_shards,
+        spec,
+    )?;
 
-    // Validator Registry
+    // Ejections.
-    process_validator_registry(state, spec)?;
+    process_ejections(state, spec)?;
 
-    // Final updates
+    // Validator Registry.
-    update_active_tree_index_roots(state, spec)?;
+    update_registry_and_shuffling_data(
-    update_latest_slashed_balances(state, spec);
+        state,
-    clean_attestations(state);
+        validator_statuses.total_balances.current_epoch,
+        spec,
+    )?;
+
+    // Slashings and exit queue.
+    process_slashings(state, validator_statuses.total_balances.current_epoch, spec)?;
+    process_exit_queue(state, spec);
+
+    // Final updates.
+    finish_epoch_update(state, spec)?;
 
     // Rotate the epoch caches to suit the epoch transition.
     state.advance_caches();
@@ -61,39 +84,10 @@ pub fn per_epoch_processing(state: &mut BeaconState, spec: &ChainSpec) -> Result
     Ok(())
 }
 
-/// Returns a list of active validator indices for the state's current epoch.
-///
-/// Spec v0.5.0
-pub fn calculate_active_validator_indices(state: &BeaconState, spec: &ChainSpec) -> Vec<usize> {
-    get_active_validator_indices(
-        &state.validator_registry,
-        state.slot.epoch(spec.slots_per_epoch),
-    )
-}
-
-/// Calculates various sets of attesters, including:
-///
-/// - current epoch attesters
-/// - current epoch boundary attesters
-/// - previous epoch attesters
-/// - etc.
-///
-/// Spec v0.5.0
-pub fn initialize_validator_statuses(
-    state: &BeaconState,
-    spec: &ChainSpec,
-) -> Result<ValidatorStatuses, BeaconStateError> {
-    let mut statuses = ValidatorStatuses::new(state, spec)?;
-
-    statuses.process_attestations(&state, spec)?;
-
-    Ok(statuses)
-}
-
 /// Maybe resets the eth1 period.
 ///
 /// Spec v0.5.0
-pub fn process_eth1_data(state: &mut BeaconState, spec: &ChainSpec) {
+pub fn maybe_reset_eth1_period(state: &mut BeaconState, spec: &ChainSpec) {
     let next_epoch = state.next_epoch(spec);
     let voting_period = spec.epochs_per_eth1_voting_period;
 
@@ -114,83 +108,68 @@ pub fn process_eth1_data(state: &mut BeaconState, spec: &ChainSpec) {
 /// - `justified_epoch`
 /// - `previous_justified_epoch`
 ///
-/// Spec v0.4.0
+/// Spec v0.5.0
-pub fn process_justification(
+pub fn update_justification_and_finalization(
     state: &mut BeaconState,
     total_balances: &TotalBalances,
     spec: &ChainSpec,
-) {
+) -> Result<(), Error> {
     let previous_epoch = state.previous_epoch(spec);
     let current_epoch = state.current_epoch(spec);
 
     let mut new_justified_epoch = state.current_justified_epoch;
+    let mut new_finalized_epoch = state.finalized_epoch;
+
+    // Rotate the justification bitfield up one epoch to make room for the current epoch.
     state.justification_bitfield <<= 1;
 
-    // If > 2/3 of the total balance attested to the previous epoch boundary
+    // If the previous epoch gets justified, full the second last bit.
-    //
+    if (total_balances.previous_epoch_boundary_attesters * 3) >= (total_balances.previous_epoch * 2)
-    // - Set the 2nd bit of the bitfield.
-    // - Set the previous epoch to be justified.
-    if (3 * total_balances.previous_epoch_boundary_attesters) >= (2 * total_balances.previous_epoch)
     {
-        state.justification_bitfield |= 2;
         new_justified_epoch = previous_epoch;
+        state.justification_bitfield |= 2;
     }
-    // If > 2/3 of the total balance attested to the previous epoch boundary
+    // If the current epoch gets justified, fill the last bit.
-    //
+    if (total_balances.current_epoch_boundary_attesters * 3) >= (total_balances.current_epoch * 2) {
-    // - Set the 1st bit of the bitfield.
-    // - Set the current epoch to be justified.
-    if (3 * total_balances.current_epoch_boundary_attesters) >= (2 * total_balances.current_epoch) {
-        state.justification_bitfield |= 1;
         new_justified_epoch = current_epoch;
+        state.justification_bitfield |= 1;
     }
 
-    // If:
+    let bitfield = state.justification_bitfield;
-    //
+
-    // - All three epochs prior to this epoch have been justified.
+    // The 2nd/3rd/4th most recent epochs are all justified, the 2nd using the 4th as source.
-    // - The previous justified justified epoch was three epochs ago.
+    if ((bitfield >> 1) % 8 == 0b111) & (state.previous_justified_epoch == current_epoch - 3) {
-    //
+        new_finalized_epoch = state.previous_justified_epoch;
-    // Then, set the finalized epoch to be three epochs ago.
-    if ((state.justification_bitfield >> 1) % 8 == 0b111)
-        & (state.previous_justified_epoch == previous_epoch - 2)
-    {
-        state.finalized_epoch = state.previous_justified_epoch;
     }
-    // If:
+    // The 2nd/3rd most recent epochs are both justified, the 2nd using the 3rd as source.
-    //
+    if ((bitfield >> 1) % 4 == 0b11) & (state.previous_justified_epoch == current_epoch - 2) {
-    // - Both two epochs prior to this epoch have been justified.
+        new_finalized_epoch = state.previous_justified_epoch;
-    // - The previous justified epoch was two epochs ago.
-    //
-    // Then, set the finalized epoch to two epochs ago.
-    if ((state.justification_bitfield >> 1) % 4 == 0b11)
-        & (state.previous_justified_epoch == previous_epoch - 1)
-    {
-        state.finalized_epoch = state.previous_justified_epoch;
     }
-    // If:
+    // The 1st/2nd/3rd most recent epochs are all justified, the 1st using the 2nd as source.
-    //
+    if (bitfield % 8 == 0b111) & (state.current_justified_epoch == current_epoch - 2) {
-    // - This epoch and the two prior have been justified.
+        new_finalized_epoch = state.current_justified_epoch;
-    // - The presently justified epoch was two epochs ago.
-    //
-    // Then, set the finalized epoch to two epochs ago.
-    if (state.justification_bitfield % 8 == 0b111)
-        & (state.current_justified_epoch == previous_epoch - 1)
-    {
-        state.finalized_epoch = state.current_justified_epoch;
     }
-    // If:
+    // The 1st/2nd most recent epochs are both justified, the 1st using the 2nd as source.
-    //
+    if (bitfield % 4 == 0b11) & (state.current_justified_epoch == current_epoch - 1) {
-    // - This epoch and the epoch prior to it have been justified.
+        new_finalized_epoch = state.current_justified_epoch;
-    // - Set the previous epoch to be justified.
-    //
-    // Then, set the finalized epoch to be the previous epoch.
-    if (state.justification_bitfield % 4 == 0b11)
-        & (state.current_justified_epoch == previous_epoch)
-    {
-        state.finalized_epoch = state.current_justified_epoch;
     }
 
     state.previous_justified_epoch = state.current_justified_epoch;
-    state.current_justified_epoch = new_justified_epoch;
+    state.previous_justified_root = state.current_justified_root;
+
+    if new_justified_epoch != state.current_justified_epoch {
+        state.current_justified_epoch = new_justified_epoch;
+        state.current_justified_root =
+            *state.get_block_root(new_justified_epoch.start_slot(spec.slots_per_epoch), spec)?;
+    }
+
+    if new_finalized_epoch != state.finalized_epoch {
+        state.finalized_epoch = new_finalized_epoch;
+        state.finalized_root =
+            *state.get_block_root(new_finalized_epoch.start_slot(spec.slots_per_epoch), spec)?;
+    }
+
+    Ok(())
 }
 
 /// Updates the following fields on the `BeaconState`:
@@ -240,238 +219,53 @@ pub fn process_crosslinks(
     Ok(winning_root_for_shards)
 }
 
-/// Updates the following fields on the BeaconState:
+/// Finish up an epoch update.
-///
-/// - `validator_balances`
-///
-/// Spec v0.4.0
-pub fn process_rewards_and_penalities(
-    state: &mut BeaconState,
-    statuses: &mut ValidatorStatuses,
-    winning_root_for_shards: &WinningRootHashSet,
-    spec: &ChainSpec,
-) -> Result<(), Error> {
-    let next_epoch = state.next_epoch(spec);
-
-    statuses.process_winning_roots(state, winning_root_for_shards, spec)?;
-
-    let total_balances = &statuses.total_balances;
-
-    let base_reward_quotient =
-        total_balances.previous_epoch.integer_sqrt() / spec.base_reward_quotient;
-
-    // Guard against a divide-by-zero during the validator balance update.
-    if base_reward_quotient == 0 {
-        return Err(Error::BaseRewardQuotientIsZero);
-    }
-    // Guard against a divide-by-zero during the validator balance update.
-    if total_balances.previous_epoch == 0 {
-        return Err(Error::PreviousTotalBalanceIsZero);
-    }
-    // Guard against an out-of-bounds during the validator balance update.
-    if statuses.statuses.len() != state.validator_balances.len() {
-        return Err(Error::ValidatorStatusesInconsistent);
-    }
-
-    // Justification and finalization
-
-    let epochs_since_finality = next_epoch - state.finalized_epoch;
-
-    state.validator_balances = state
-        .validator_balances
-        .par_iter()
-        .enumerate()
-        .map(|(index, &balance)| {
-            let mut balance = balance;
-            let status = &statuses.statuses[index];
-            let base_reward = get_base_reward(state, index, total_balances.previous_epoch, spec)
-                .expect(
-                    "Cannot fail to access a validator balance when iterating validator balances.",
-                );
-
-            if epochs_since_finality <= 4 {
-                // Expected FFG source
-                if status.is_previous_epoch_attester {
-                    safe_add_assign!(
-                        balance,
-                        base_reward * total_balances.previous_epoch_attesters
-                            / total_balances.previous_epoch
-                    );
-                } else if status.is_active_in_previous_epoch {
-                    safe_sub_assign!(balance, base_reward);
-                }
-
-                // Expected FFG target
-                if status.is_previous_epoch_boundary_attester {
-                    safe_add_assign!(
-                        balance,
-                        base_reward * total_balances.previous_epoch_boundary_attesters
-                            / total_balances.previous_epoch
-                    );
-                } else if status.is_active_in_previous_epoch {
-                    safe_sub_assign!(balance, base_reward);
-                }
-
-                // Expected beacon chain head
-                if status.is_previous_epoch_head_attester {
-                    safe_add_assign!(
-                        balance,
-                        base_reward * total_balances.previous_epoch_head_attesters
-                            / total_balances.previous_epoch
-                    );
-                } else if status.is_active_in_previous_epoch {
-                    safe_sub_assign!(balance, base_reward);
-                };
-            } else {
-                let inactivity_penalty = get_inactivity_penalty(
-                    state,
-                    index,
-                    epochs_since_finality.as_u64(),
-                    total_balances.previous_epoch,
-                    spec,
-                )
-                .expect(
-                    "Cannot fail to access a validator balance when iterating validator balances.",
-                );
-
-                if status.is_active_in_previous_epoch {
-                    if !status.is_previous_epoch_attester {
-                        safe_sub_assign!(balance, inactivity_penalty);
-                    }
-                    if !status.is_previous_epoch_boundary_attester {
-                        safe_sub_assign!(balance, inactivity_penalty);
-                    }
-                    if !status.is_previous_epoch_head_attester {
-                        safe_sub_assign!(balance, inactivity_penalty);
-                    }
-
-                    if state.validator_registry[index].slashed {
-                        let base_reward =
-                            get_base_reward(state, index, total_balances.previous_epoch, spec).expect(
-                                "Cannot fail to access a validator balance when iterating validator balances.",
-                            );
-                        safe_sub_assign!(balance, 2 * inactivity_penalty + base_reward);
-                    }
-                }
-            }
-
-            // Crosslinks
-
-            if let Some(ref info) = status.winning_root_info {
-                safe_add_assign!(
-                    balance,
-                    base_reward * info.total_attesting_balance / info.total_committee_balance
-                );
-            } else {
-                safe_sub_assign!(balance, base_reward);
-            }
-
-            balance
-        })
-        .collect();
-
-    // Attestation inclusion
-
-    // Guard against an out-of-bounds during the attester inclusion balance update.
-    if statuses.statuses.len() != state.validator_registry.len() {
-        return Err(Error::ValidatorStatusesInconsistent);
-    }
-
-    for (index, _validator) in state.validator_registry.iter().enumerate() {
-        let status = &statuses.statuses[index];
-
-        if status.is_previous_epoch_attester {
-            let proposer_index = status.inclusion_info.proposer_index;
-            let inclusion_distance = status.inclusion_info.distance;
-
-            let base_reward =
-                get_base_reward(state, proposer_index, total_balances.previous_epoch, spec).expect(
-                    "Cannot fail to access a validator balance when iterating validator balances.",
-                );
-
-            if inclusion_distance > 0 && inclusion_distance < Slot::max_value() {
-                safe_add_assign!(
-                    state.validator_balances[proposer_index],
-                    base_reward * spec.min_attestation_inclusion_delay
-                        / inclusion_distance.as_u64()
-                )
-            }
-        }
-    }
-
-    Ok(())
-}
-
-/// Returns the base reward for some validator.
 ///
 /// Spec v0.5.0
-pub fn get_base_reward(
+pub fn finish_epoch_update(state: &mut BeaconState, spec: &ChainSpec) -> Result<(), Error> {
-    state: &BeaconState,
-    index: usize,
-    previous_total_balance: u64,
-    spec: &ChainSpec,
-) -> Result<u64, BeaconStateError> {
-    if previous_total_balance == 0 {
-        Ok(0)
-    } else {
-        let adjusted_quotient = previous_total_balance.integer_sqrt() / spec.base_reward_quotient;
-        Ok(state.get_effective_balance(index, spec)? / adjusted_quotient / 5)
-    }
-}
-
-/// Returns the inactivity penalty for some validator.
-///
-/// Spec v0.5.0
-pub fn get_inactivity_penalty(
-    state: &BeaconState,
-    index: usize,
-    epochs_since_finality: u64,
-    previous_total_balance: u64,
-    spec: &ChainSpec,
-) -> Result<u64, BeaconStateError> {
-    Ok(get_base_reward(state, index, previous_total_balance, spec)?
-        + state.get_effective_balance(index, spec)? * epochs_since_finality
-            / spec.inactivity_penalty_quotient
-            / 2)
-}
-
-/// Updates the state's `latest_active_index_roots` field with a tree hash the active validator
-/// indices for the next epoch.
-///
-/// Spec v0.4.0
-pub fn update_active_tree_index_roots(
-    state: &mut BeaconState,
-    spec: &ChainSpec,
-) -> Result<(), Error> {
-    let next_epoch = state.next_epoch(spec);
-
-    let active_tree_root = get_active_validator_indices(
-        &state.validator_registry,
-        next_epoch + Epoch::from(spec.activation_exit_delay),
-    )
-    .hash_tree_root();
-
-    state.latest_active_index_roots[(next_epoch.as_usize()
-        + spec.activation_exit_delay as usize)
-        % spec.latest_active_index_roots_length] = Hash256::from_slice(&active_tree_root[..]);
-
-    Ok(())
-}
-
-/// Advances the state's `latest_slashed_balances` field.
-///
-/// Spec v0.4.0
-pub fn update_latest_slashed_balances(state: &mut BeaconState, spec: &ChainSpec) {
     let current_epoch = state.current_epoch(spec);
     let next_epoch = state.next_epoch(spec);
 
-    state.latest_slashed_balances[next_epoch.as_usize() % spec.latest_slashed_exit_length] =
+    // This is a hack to allow us to update index roots and slashed balances for the next epoch.
-        state.latest_slashed_balances[current_epoch.as_usize() % spec.latest_slashed_exit_length];
+    //
-}
+    // The indentation here is to make it obvious where the weird stuff happens.
+    {
+        state.slot += 1;
 
-/// Removes all pending attestations from the previous epoch.
+        // Set active index root
-///
+        let active_index_root = Hash256::from_slice(
-/// Spec v0.4.0
+            &state
-pub fn clean_attestations(state: &mut BeaconState) {
+                .get_active_validator_indices(next_epoch + spec.activation_exit_delay)
-    state.previous_epoch_attestations = vec![];
+                .hash_tree_root()[..],
+        );
+        state.set_active_index_root(next_epoch, active_index_root, spec)?;
+
+        // Set total slashed balances
+        state.set_slashed_balance(
+            next_epoch,
+            state.get_slashed_balance(current_epoch, spec)?,
+            spec,
+        )?;
+
+        // Set randao mix
+        state.set_randao_mix(
+            next_epoch,
+            *state.get_randao_mix(current_epoch, spec)?,
+            spec,
+        )?;
+
+        state.slot -= 1;
+    }
+
+    if next_epoch.as_u64() % (spec.slots_per_historical_root as u64 / spec.slots_per_epoch) == 0 {
+        let historical_batch: HistoricalBatch = state.historical_batch();
+        state
+            .historical_roots
+            .push(Hash256::from_slice(&historical_batch.hash_tree_root()[..]));
+    }
+
+    state.previous_epoch_attestations = state.current_epoch_attestations.clone();
+    state.current_epoch_attestations = vec![];
+
+    Ok(())
 }

eth2/state_processing/src/per_epoch_processing/apply_rewards.rs

@@ -0,0 +1,334 @@
+use super::validator_statuses::{TotalBalances, ValidatorStatus, ValidatorStatuses};
+use super::{Error, WinningRootHashSet};
+use integer_sqrt::IntegerSquareRoot;
+use types::*;
+
+/// Use to track the changes to a validators balance.
+#[derive(Default, Clone)]
+pub struct Delta {
+    rewards: u64,
+    penalties: u64,
+}
+
+impl Delta {
+    /// Reward the validator with the `reward`.
+    pub fn reward(&mut self, reward: u64) {
+        self.rewards += reward;
+    }
+
+    /// Penalize the validator with the `penalty`.
+    pub fn penalize(&mut self, penalty: u64) {
+        self.penalties += penalty;
+    }
+}
+
+impl std::ops::AddAssign for Delta {
+    /// Use wrapping addition as that is how it's defined in the spec.
+    fn add_assign(&mut self, other: Delta) {
+        self.rewards += other.rewards;
+        self.penalties += other.penalties;
+    }
+}
+
+/// Apply attester and proposer rewards.
+///
+/// Spec v0.5.0
+pub fn apply_rewards(
+    state: &mut BeaconState,
+    validator_statuses: &mut ValidatorStatuses,
+    winning_root_for_shards: &WinningRootHashSet,
+    spec: &ChainSpec,
+) -> Result<(), Error> {
+    // Guard against an out-of-bounds during the validator balance update.
+    if validator_statuses.statuses.len() != state.validator_balances.len() {
+        return Err(Error::ValidatorStatusesInconsistent);
+    }
+    // Guard against an out-of-bounds during the attester inclusion balance update.
+    if validator_statuses.statuses.len() != state.validator_registry.len() {
+        return Err(Error::ValidatorStatusesInconsistent);
+    }
+
+    let mut deltas = vec![Delta::default(); state.validator_balances.len()];
+
+    get_justification_and_finalization_deltas(&mut deltas, state, &validator_statuses, spec)?;
+    get_crosslink_deltas(&mut deltas, state, &validator_statuses, spec)?;
+
+    // Apply the proposer deltas if we are finalizing normally.
+    //
+    // This is executed slightly differently to the spec because of the way our functions are
+    // structured. It should be functionally equivalent.
+    if epochs_since_finality(state, spec) <= 4 {
+        get_proposer_deltas(
+            &mut deltas,
+            state,
+            validator_statuses,
+            winning_root_for_shards,
+            spec,
+        )?;
+    }
+
+    // Apply the deltas, over-flowing but not under-flowing (saturating at 0 instead).
+    for (i, delta) in deltas.iter().enumerate() {
+        state.validator_balances[i] += delta.rewards;
+        state.validator_balances[i] = state.validator_balances[i].saturating_sub(delta.penalties);
+    }
+
+    Ok(())
+}
+
+/// Applies the attestation inclusion reward to each proposer for every validator who included an
+/// attestation in the previous epoch.
+///
+/// Spec v0.5.0
+fn get_proposer_deltas(
+    deltas: &mut Vec<Delta>,
+    state: &mut BeaconState,
+    validator_statuses: &mut ValidatorStatuses,
+    winning_root_for_shards: &WinningRootHashSet,
+    spec: &ChainSpec,
+) -> Result<(), Error> {
+    // Update statuses with the information from winning roots.
+    validator_statuses.process_winning_roots(state, winning_root_for_shards, spec)?;
+
+    for (index, validator) in validator_statuses.statuses.iter().enumerate() {
+        let mut delta = Delta::default();
+
+        if validator.is_previous_epoch_attester {
+            let inclusion = validator
+                .inclusion_info
+                .expect("It is a logic error for an attester not to have an inclusion distance.");
+
+            let base_reward = get_base_reward(
+                state,
+                inclusion.proposer_index,
+                validator_statuses.total_balances.previous_epoch,
+                spec,
+            )?;
+
+            if inclusion.proposer_index >= deltas.len() {
+                return Err(Error::ValidatorStatusesInconsistent);
+            }
+
+            delta.reward(base_reward / spec.attestation_inclusion_reward_quotient);
+        }
+
+        deltas[index] += delta;
+    }
+
+    Ok(())
+}
+
+/// Apply rewards for participation in attestations during the previous epoch.
+///
+/// Spec v0.5.0
+fn get_justification_and_finalization_deltas(
+    deltas: &mut Vec<Delta>,
+    state: &BeaconState,
+    validator_statuses: &ValidatorStatuses,
+    spec: &ChainSpec,
+) -> Result<(), Error> {
+    let epochs_since_finality = epochs_since_finality(state, spec);
+
+    for (index, validator) in validator_statuses.statuses.iter().enumerate() {
+        let base_reward = get_base_reward(
+            state,
+            index,
+            validator_statuses.total_balances.previous_epoch,
+            spec,
+        )?;
+        let inactivity_penalty = get_inactivity_penalty(
+            state,
+            index,
+            epochs_since_finality.as_u64(),
+            validator_statuses.total_balances.previous_epoch,
+            spec,
+        )?;
+
+        let delta = if epochs_since_finality <= 4 {
+            compute_normal_justification_and_finalization_delta(
+                &validator,
+                &validator_statuses.total_balances,
+                base_reward,
+                spec,
+            )
+        } else {
+            compute_inactivity_leak_delta(&validator, base_reward, inactivity_penalty, spec)
+        };
+
+        deltas[index] += delta;
+    }
+
+    Ok(())
+}
+
+/// Determine the delta for a single validator, if the chain is finalizing normally.
+///
+/// Spec v0.5.0
+fn compute_normal_justification_and_finalization_delta(
+    validator: &ValidatorStatus,
+    total_balances: &TotalBalances,
+    base_reward: u64,
+    spec: &ChainSpec,
+) -> Delta {
+    let mut delta = Delta::default();
+
+    let boundary_attesting_balance = total_balances.previous_epoch_boundary_attesters;
+    let total_balance = total_balances.previous_epoch;
+    let total_attesting_balance = total_balances.previous_epoch_attesters;
+    let matching_head_balance = total_balances.previous_epoch_boundary_attesters;
+
+    // Expected FFG source.
+    if validator.is_previous_epoch_attester {
+        delta.reward(base_reward * total_attesting_balance / total_balance);
+        // Inclusion speed bonus
+        let inclusion = validator
+            .inclusion_info
+            .expect("It is a logic error for an attester not to have an inclusion distance.");
+        delta.reward(
+            base_reward * spec.min_attestation_inclusion_delay / inclusion.distance.as_u64(),
+        );
+    } else if validator.is_active_in_previous_epoch {
+        delta.penalize(base_reward);
+    }
+
+    // Expected FFG target.
+    if validator.is_previous_epoch_boundary_attester {
+        delta.reward(base_reward / boundary_attesting_balance / total_balance);
+    } else if validator.is_active_in_previous_epoch {
+        delta.penalize(base_reward);
+    }
+
+    // Expected head.
+    if validator.is_previous_epoch_head_attester {
+        delta.reward(base_reward * matching_head_balance / total_balance);
+    } else if validator.is_active_in_previous_epoch {
+        delta.penalize(base_reward);
+    };
+
+    // Proposer bonus is handled in `apply_proposer_deltas`.
+    //
+    // This function only computes the delta for a single validator, so it cannot also return a
+    // delta for a validator.
+
+    delta
+}
+
+/// Determine the delta for a single delta, assuming the chain is _not_ finalizing normally.
+///
+/// Spec v0.5.0
+fn compute_inactivity_leak_delta(
+    validator: &ValidatorStatus,
+    base_reward: u64,
+    inactivity_penalty: u64,
+    spec: &ChainSpec,
+) -> Delta {
+    let mut delta = Delta::default();
+
+    if validator.is_active_in_previous_epoch {
+        if !validator.is_previous_epoch_attester {
+            delta.penalize(inactivity_penalty);
+        } else {
+            // If a validator did attest, apply a small penalty for getting attestations included
+            // late.
+            let inclusion = validator
+                .inclusion_info
+                .expect("It is a logic error for an attester not to have an inclusion distance.");
+            delta.reward(
+                base_reward * spec.min_attestation_inclusion_delay / inclusion.distance.as_u64(),
+            );
+            delta.penalize(base_reward);
+        }
+
+        if !validator.is_previous_epoch_boundary_attester {
+            delta.reward(inactivity_penalty);
+        }
+
+        if !validator.is_previous_epoch_head_attester {
+            delta.penalize(inactivity_penalty);
+        }
+    }
+
+    // Penalize slashed-but-inactive validators as though they were active but offline.
+    if !validator.is_active_in_previous_epoch
+        & validator.is_slashed
+        & !validator.is_withdrawable_in_current_epoch
+    {
+        delta.penalize(2 * inactivity_penalty + base_reward);
+    }
+
+    delta
+}
+
+/// Calculate the deltas based upon the winning roots for attestations during the previous epoch.
+///
+/// Spec v0.5.0
+fn get_crosslink_deltas(
+    deltas: &mut Vec<Delta>,
+    state: &BeaconState,
+    validator_statuses: &ValidatorStatuses,
+    spec: &ChainSpec,
+) -> Result<(), Error> {
+    for (index, validator) in validator_statuses.statuses.iter().enumerate() {
+        let mut delta = Delta::default();
+
+        let base_reward = get_base_reward(
+            state,
+            index,
+            validator_statuses.total_balances.previous_epoch,
+            spec,
+        )?;
+
+        if let Some(ref winning_root) = validator.winning_root_info {
+            delta.reward(
+                base_reward * winning_root.total_attesting_balance
+                    / winning_root.total_committee_balance,
+            );
+        } else {
+            delta.penalize(base_reward);
+        }
+
+        deltas[index] += delta;
+    }
+
+    Ok(())
+}
+
+/// Returns the base reward for some validator.
+///
+/// Spec v0.5.0
+fn get_base_reward(
+    state: &BeaconState,
+    index: usize,
+    previous_total_balance: u64,
+    spec: &ChainSpec,
+) -> Result<u64, BeaconStateError> {
+    if previous_total_balance == 0 {
+        Ok(0)
+    } else {
+        let adjusted_quotient = previous_total_balance.integer_sqrt() / spec.base_reward_quotient;
+        Ok(state.get_effective_balance(index, spec)? / adjusted_quotient / 5)
+    }
+}
+
+/// Returns the inactivity penalty for some validator.
+///
+/// Spec v0.5.0
+fn get_inactivity_penalty(
+    state: &BeaconState,
+    index: usize,
+    epochs_since_finality: u64,
+    previous_total_balance: u64,
+    spec: &ChainSpec,
+) -> Result<u64, BeaconStateError> {
+    Ok(get_base_reward(state, index, previous_total_balance, spec)?
+        + state.get_effective_balance(index, spec)? * epochs_since_finality
+            / spec.inactivity_penalty_quotient
+            / 2)
+}
+
+/// Returns the epochs since the last finalized epoch.
+///
+/// Spec v0.5.0
+fn epochs_since_finality(state: &BeaconState, spec: &ChainSpec) -> Epoch {
+    state.current_epoch(spec) + 1 - state.finalized_epoch
+}

eth2/state_processing/src/per_epoch_processing/errors.rs

@@ -9,6 +9,7 @@ pub enum EpochProcessingError {
     PreviousTotalBalanceIsZero,
     InclusionDistanceZero,
     ValidatorStatusesInconsistent,
+    DeltasInconsistent,
     /// Unable to get the inclusion distance for a validator that should have an inclusion
     /// distance. This indicates an internal inconsistency.
     ///

eth2/state_processing/src/per_epoch_processing/get_attestation_participants.rs

@@ -1,4 +1,5 @@
-use types::{beacon_state::helpers::verify_bitfield_length, *};
+use crate::common::verify_bitfield_length;
+use types::*;
 
 /// Returns validator indices which participated in the attestation.
 ///
@@ -27,7 +28,7 @@ pub fn get_attestation_participants(
     let mut participants = Vec::with_capacity(committee.len());
     for (i, validator_index) in committee.iter().enumerate() {
         match bitfield.get(i) {
-            Ok(bit) if bit == true => participants.push(*validator_index),
+            Ok(bit) if bit => participants.push(*validator_index),
             _ => {}
         }
     }

eth2/state_processing/src/per_epoch_processing/process_ejections.rs

@@ -0,0 +1,28 @@
+use crate::common::exit_validator;
+use types::{BeaconStateError as Error, *};
+
+/// Iterate through the validator registry and eject active validators with balance below
+/// ``EJECTION_BALANCE``.
+///
+/// Spec v0.5.0
+pub fn process_ejections(state: &mut BeaconState, spec: &ChainSpec) -> Result<(), Error> {
+    // There is an awkward double (triple?) loop here because we can't loop across the borrowed
+    // active validator indices and mutate state in the one loop.
+    let exitable: Vec<usize> = state
+        .get_cached_active_validator_indices(RelativeEpoch::Current, spec)?
+        .iter()
+        .filter_map(|&i| {
+            if state.validator_balances[i as usize] < spec.ejection_balance {
+                Some(i)
+            } else {
+                None
+            }
+        })
+        .collect();
+
+    for validator_index in exitable {
+        exit_validator(state, validator_index, spec)?
+    }
+
+    Ok(())
+}

eth2/state_processing/src/per_epoch_processing/process_exit_queue.rs

@@ -0,0 +1,42 @@
+use types::*;
+
+/// Process the exit queue.
+///
+/// Spec v0.5.0
+pub fn process_exit_queue(state: &mut BeaconState, spec: &ChainSpec) {
+    let current_epoch = state.current_epoch(spec);
+
+    let eligible = |index: usize| {
+        let validator = &state.validator_registry[index];
+
+        if validator.withdrawable_epoch != spec.far_future_epoch {
+            false
+        } else {
+            current_epoch >= validator.exit_epoch + spec.min_validator_withdrawability_delay
+        }
+    };
+
+    let mut eligable_indices: Vec<usize> = (0..state.validator_registry.len())
+        .filter(|i| eligible(*i))
+        .collect();
+    eligable_indices.sort_by_key(|i| state.validator_registry[*i].exit_epoch);
+
+    for (dequeues, index) in eligable_indices.iter().enumerate() {
+        if dequeues as u64 >= spec.max_exit_dequeues_per_epoch {
+            break;
+        }
+        prepare_validator_for_withdrawal(state, *index, spec);
+    }
+}
+
+/// Initiate an exit for the validator of the given `index`.
+///
+/// Spec v0.5.0
+fn prepare_validator_for_withdrawal(
+    state: &mut BeaconState,
+    validator_index: usize,
+    spec: &ChainSpec,
+) {
+    state.validator_registry[validator_index].withdrawable_epoch =
+        state.current_epoch(spec) + spec.min_validator_withdrawability_delay;
+}

eth2/state_processing/src/per_epoch_processing/process_slashings.rs

@@ -0,0 +1,35 @@
+use types::{BeaconStateError as Error, *};
+
+/// Process slashings.
+///
+/// Spec v0.5.0
+pub fn process_slashings(
+    state: &mut BeaconState,
+    current_total_balance: u64,
+    spec: &ChainSpec,
+) -> Result<(), Error> {
+    let current_epoch = state.current_epoch(spec);
+
+    let total_at_start = state.get_slashed_balance(current_epoch + 1, spec)?;
+    let total_at_end = state.get_slashed_balance(current_epoch, spec)?;
+    let total_penalities = total_at_end - total_at_start;
+
+    for (index, validator) in state.validator_registry.iter().enumerate() {
+        let should_penalize = current_epoch.as_usize()
+            == validator.withdrawable_epoch.as_usize() - spec.latest_slashed_exit_length / 2;
+
+        if validator.slashed && should_penalize {
+            let effective_balance = state.get_effective_balance(index, spec)?;
+
+            let penalty = std::cmp::max(
+                effective_balance * std::cmp::min(total_penalities * 3, current_total_balance)
+                    / current_total_balance,
+                effective_balance / spec.min_penalty_quotient,
+            );
+
+            state.validator_balances[index] -= penalty;
+        }
+    }
+
+    Ok(())
+}

eth2/state_processing/src/per_epoch_processing/process_validator_registry.rs

@@ -1,72 +0,0 @@
-use super::Error;
-use types::*;
-
-/// Peforms a validator registry update, if required.
-///
-/// Spec v0.4.0
-pub fn process_validator_registry(state: &mut BeaconState, spec: &ChainSpec) -> Result<(), Error> {
-    let current_epoch = state.current_epoch(spec);
-    let next_epoch = state.next_epoch(spec);
-
-    state.previous_shuffling_epoch = state.current_shuffling_epoch;
-    state.previous_shuffling_start_shard = state.current_shuffling_start_shard;
-
-    state.previous_shuffling_seed = state.current_shuffling_seed;
-
-    if should_update_validator_registry(state, spec)? {
-        state.update_validator_registry(spec)?;
-
-        state.current_shuffling_epoch = next_epoch;
-        state.current_shuffling_start_shard = (state.current_shuffling_start_shard
-            + spec.get_epoch_committee_count(
-                state
-                    .get_active_validator_indices(current_epoch, spec)?
-                    .len(),
-            ) as u64)
-            % spec.shard_count;
-        state.current_shuffling_seed = state.generate_seed(state.current_shuffling_epoch, spec)?
-    } else {
-        let epochs_since_last_registry_update =
-            current_epoch - state.validator_registry_update_epoch;
-        if (epochs_since_last_registry_update > 1)
-            & epochs_since_last_registry_update.is_power_of_two()
-        {
-            state.current_shuffling_epoch = next_epoch;
-            state.current_shuffling_seed =
-                state.generate_seed(state.current_shuffling_epoch, spec)?
-        }
-    }
-
-    state.process_slashings(spec)?;
-    state.process_exit_queue(spec);
-
-    Ok(())
-}
-
-/// Returns `true` if the validator registry should be updated during an epoch processing.
-///
-/// Spec v0.5.0
-pub fn should_update_validator_registry(
-    state: &BeaconState,
-    spec: &ChainSpec,
-) -> Result<bool, BeaconStateError> {
-    if state.finalized_epoch <= state.validator_registry_update_epoch {
-        return Ok(false);
-    }
-
-    let num_active_validators = state
-        .get_active_validator_indices(state.current_epoch(spec), spec)?
-        .len();
-    let current_epoch_committee_count = spec.get_epoch_committee_count(num_active_validators);
-
-    for shard in (0..current_epoch_committee_count)
-        .into_iter()
-        .map(|i| (state.current_shuffling_start_shard + i as u64) % spec.shard_count)
-    {
-        if state.latest_crosslinks[shard as usize].epoch <= state.validator_registry_update_epoch {
-            return Ok(false);
-        }
-    }
-
-    Ok(true)
-}

eth2/state_processing/src/per_epoch_processing/update_registry_and_shuffling_data.rs

@@ -0,0 +1,150 @@
+use super::super::common::exit_validator;
+use super::Error;
+use types::*;
+
+/// Peforms a validator registry update, if required.
+///
+/// Spec v0.5.0
+pub fn update_registry_and_shuffling_data(
+    state: &mut BeaconState,
+    current_total_balance: u64,
+    spec: &ChainSpec,
+) -> Result<(), Error> {
+    // First set previous shuffling data to current shuffling data.
+    state.previous_shuffling_epoch = state.current_shuffling_epoch;
+    state.previous_shuffling_start_shard = state.previous_shuffling_start_shard;
+    state.previous_shuffling_seed = state.previous_shuffling_seed;
+
+    let current_epoch = state.current_epoch(spec);
+    let next_epoch = current_epoch + 1;
+
+    // Check we should update, and if so, update.
+    if should_update_validator_registry(state, spec)? {
+        update_validator_registry(state, current_total_balance, spec)?;
+
+        // If we update the registry, update the shuffling data and shards as well.
+        state.current_shuffling_epoch = next_epoch;
+        state.current_shuffling_start_shard = {
+            let active_validators =
+                state.get_cached_active_validator_indices(RelativeEpoch::Current, spec)?;
+            let epoch_committee_count = spec.get_epoch_committee_count(active_validators.len());
+
+            (state.current_shuffling_start_shard + epoch_committee_count) % spec.shard_count
+        };
+        state.current_shuffling_seed = state.generate_seed(state.current_shuffling_epoch, spec)?;
+    } else {
+        // If processing at least on crosslink keeps failing, the reshuffle every power of two, but
+        // don't update the current_shuffling_start_shard.
+        let epochs_since_last_update = current_epoch - state.validator_registry_update_epoch;
+
+        if epochs_since_last_update > 1 && epochs_since_last_update.is_power_of_two() {
+            state.current_shuffling_epoch = next_epoch;
+            state.current_shuffling_seed =
+                state.generate_seed(state.current_shuffling_epoch, spec)?;
+        }
+    }
+
+    Ok(())
+}
+
+/// Returns `true` if the validator registry should be updated during an epoch processing.
+///
+/// Spec v0.5.0
+pub fn should_update_validator_registry(
+    state: &BeaconState,
+    spec: &ChainSpec,
+) -> Result<bool, BeaconStateError> {
+    if state.finalized_epoch <= state.validator_registry_update_epoch {
+        return Ok(false);
+    }
+
+    let num_active_validators = state
+        .get_cached_active_validator_indices(RelativeEpoch::Current, spec)?
+        .len();
+    let current_epoch_committee_count = spec.get_epoch_committee_count(num_active_validators);
+
+    for shard in (0..current_epoch_committee_count)
+        .map(|i| (state.current_shuffling_start_shard + i as u64) % spec.shard_count)
+    {
+        if state.latest_crosslinks[shard as usize].epoch <= state.validator_registry_update_epoch {
+            return Ok(false);
+        }
+    }
+
+    Ok(true)
+}
+
+/// Update validator registry, activating/exiting validators if possible.
+///
+/// Note: Utilizes the cache and will fail if the appropriate cache is not initialized.
+///
+/// Spec v0.5.0
+pub fn update_validator_registry(
+    state: &mut BeaconState,
+    current_total_balance: u64,
+    spec: &ChainSpec,
+) -> Result<(), Error> {
+    let current_epoch = state.current_epoch(spec);
+
+    let max_balance_churn = std::cmp::max(
+        spec.max_deposit_amount,
+        current_total_balance / (2 * spec.max_balance_churn_quotient),
+    );
+
+    // Activate validators within the allowable balance churn.
+    let mut balance_churn = 0;
+    for index in 0..state.validator_registry.len() {
+        let not_activated =
+            state.validator_registry[index].activation_epoch == spec.far_future_epoch;
+        let has_enough_balance = state.validator_balances[index] >= spec.max_deposit_amount;
+
+        if not_activated && has_enough_balance {
+            // Check the balance churn would be within the allowance.
+            balance_churn += state.get_effective_balance(index, spec)?;
+            if balance_churn > max_balance_churn {
+                break;
+            }
+
+            activate_validator(state, index, false, spec);
+        }
+    }
+
+    // Exit validators within the allowable balance churn.
+    let mut balance_churn = 0;
+    for index in 0..state.validator_registry.len() {
+        let not_exited = state.validator_registry[index].exit_epoch == spec.far_future_epoch;
+        let has_initiated_exit = state.validator_registry[index].initiated_exit;
+
+        if not_exited && has_initiated_exit {
+            // Check the balance churn would be within the allowance.
+            balance_churn += state.get_effective_balance(index, spec)?;
+            if balance_churn > max_balance_churn {
+                break;
+            }
+
+            exit_validator(state, index, spec)?;
+        }
+    }
+
+    state.validator_registry_update_epoch = current_epoch;
+
+    Ok(())
+}
+
+/// Activate the validator of the given ``index``.
+///
+/// Spec v0.5.0
+pub fn activate_validator(
+    state: &mut BeaconState,
+    validator_index: usize,
+    is_genesis: bool,
+    spec: &ChainSpec,
+) {
+    let current_epoch = state.current_epoch(spec);
+
+    state.validator_registry[validator_index].activation_epoch = if is_genesis {
+        spec.genesis_epoch
+    } else {
+        state.get_delayed_activation_exit_epoch(current_epoch, spec)
+    }
+}

eth2/state_processing/src/per_epoch_processing/validator_statuses.rs

@@ -23,7 +23,7 @@ pub struct WinningRootInfo {
 }
 
 /// The information required to reward a block producer for including an attestation in a block.
-#[derive(Clone)]
+#[derive(Clone, Copy)]
 pub struct InclusionInfo {
     /// The earliest slot a validator had an attestation included in the previous epoch.
     pub slot: Slot,
@@ -59,7 +59,11 @@ impl InclusionInfo {
 
 /// Information required to reward some validator during the current and previous epoch.
 #[derive(Default, Clone)]
-pub struct AttesterStatus {
+pub struct ValidatorStatus {
+    /// True if the validator has been slashed, ever.
+    pub is_slashed: bool,
+    /// True if the validator can withdraw in the current epoch.
+    pub is_withdrawable_in_current_epoch: bool,
     /// True if the validator was active in the state's _current_ epoch.
     pub is_active_in_current_epoch: bool,
     /// True if the validator was active in the state's _previous_ epoch.
@@ -81,14 +85,14 @@ pub struct AttesterStatus {
 
     /// Information used to reward the block producer of this validators earliest-included
     /// attestation.
-    pub inclusion_info: InclusionInfo,
+    pub inclusion_info: Option<InclusionInfo>,
     /// Information used to reward/penalize the validator if they voted in the super-majority for
     /// some shard block.
     pub winning_root_info: Option<WinningRootInfo>,
 }
 
-impl AttesterStatus {
+impl ValidatorStatus {
-    /// Accepts some `other` `AttesterStatus` and updates `self` if required.
+    /// Accepts some `other` `ValidatorStatus` and updates `self` if required.
     ///
     /// Will never set one of the `bool` fields to `false`, it will only set it to `true` if other
     /// contains a `true` field.
@@ -97,6 +101,8 @@ impl AttesterStatus {
     pub fn update(&mut self, other: &Self) {
         // Update all the bool fields, only updating `self` if `other` is true (never setting
         // `self` to false).
+        set_self_if_other_is_true!(self, other, is_slashed);
+        set_self_if_other_is_true!(self, other, is_withdrawable_in_current_epoch);
         set_self_if_other_is_true!(self, other, is_active_in_current_epoch);
         set_self_if_other_is_true!(self, other, is_active_in_previous_epoch);
         set_self_if_other_is_true!(self, other, is_current_epoch_attester);
@@ -105,7 +111,13 @@ impl AttesterStatus {
         set_self_if_other_is_true!(self, other, is_previous_epoch_boundary_attester);
         set_self_if_other_is_true!(self, other, is_previous_epoch_head_attester);
 
-        self.inclusion_info.update(&other.inclusion_info);
+        if let Some(other_info) = other.inclusion_info {
+            if let Some(self_info) = self.inclusion_info.as_mut() {
+                self_info.update(&other_info);
+            } else {
+                self.inclusion_info = other.inclusion_info;
+            }
+        }
     }
 }
 
@@ -137,7 +149,7 @@ pub struct TotalBalances {
 #[derive(Clone)]
 pub struct ValidatorStatuses {
     /// Information about each individual validator from the state's validator registy.
-    pub statuses: Vec<AttesterStatus>,
+    pub statuses: Vec<ValidatorStatus>,
     /// Summed balances for various sets of validators.
     pub total_balances: TotalBalances,
 }
@@ -154,7 +166,12 @@ impl ValidatorStatuses {
         let mut total_balances = TotalBalances::default();
 
         for (i, validator) in state.validator_registry.iter().enumerate() {
-            let mut status = AttesterStatus::default();
+            let mut status = ValidatorStatus {
+                is_slashed: validator.slashed,
+                is_withdrawable_in_current_epoch: validator
+                    .is_withdrawable_at(state.current_epoch(spec)),
+                ..ValidatorStatus::default()
+            };
 
             if validator.is_active_at(state.current_epoch(spec)) {
                 status.is_active_in_current_epoch = true;
@@ -193,10 +210,10 @@ impl ValidatorStatuses {
                 get_attestation_participants(state, &a.data, &a.aggregation_bitfield, spec)?;
             let attesting_balance = state.get_total_balance(&attesting_indices, spec)?;
 
-            let mut status = AttesterStatus::default();
+            let mut status = ValidatorStatus::default();
 
             // Profile this attestation, updating the total balances and generating an
-            // `AttesterStatus` object that applies to all participants in the attestation.
+            // `ValidatorStatus` object that applies to all participants in the attestation.
             if is_from_epoch(a, state.current_epoch(spec), spec) {
                 self.total_balances.current_epoch_attesters += attesting_balance;
                 status.is_current_epoch_attester = true;
@@ -211,7 +228,7 @@ impl ValidatorStatuses {
 
                 // The inclusion slot and distance are only required for previous epoch attesters.
                 let relative_epoch = RelativeEpoch::from_slot(state.slot, a.data.slot, spec)?;
-                status.inclusion_info = InclusionInfo {
+                status.inclusion_info = Some(InclusionInfo {
                     slot: a.inclusion_slot,
                     distance: inclusion_distance(a),
                     proposer_index: state.get_beacon_proposer_index(
@@ -219,7 +236,7 @@ impl ValidatorStatuses {
                         relative_epoch,
                         spec,
                     )?,
-                };
+                });
 
                 if has_common_epoch_boundary_root(a, state, state.previous_epoch(spec), spec)? {
                     self.total_balances.previous_epoch_boundary_attesters += attesting_balance;

eth2/state_processing/src/per_slot_processing.rs

@@ -25,9 +25,6 @@ pub fn per_slot_processing(
 
     state.slot += 1;
 
-    let latest_block_root = Hash256::from_slice(&state.latest_block_header.hash_tree_root()[..]);
-    state.set_block_root(state.slot - 1, latest_block_root, spec)?;
-
     Ok(())
 }
 

eth2/types/src/beacon_block.rs

@@ -71,7 +71,7 @@ impl BeaconBlock {
     /// Note: performs a full tree-hash of `self.body`.
     ///
     /// Spec v0.5.0
-    pub fn into_header(&self) -> BeaconBlockHeader {
+    pub fn block_header(&self) -> BeaconBlockHeader {
         BeaconBlockHeader {
             slot: self.slot,
             previous_block_root: self.previous_block_root,
@@ -84,11 +84,11 @@ impl BeaconBlock {
     /// Returns a "temporary" header, where the `state_root` is `spec.zero_hash`.
     ///
     /// Spec v0.5.0
-    pub fn into_temporary_header(&self, spec: &ChainSpec) -> BeaconBlockHeader {
+    pub fn temporary_block_header(&self, spec: &ChainSpec) -> BeaconBlockHeader {
         BeaconBlockHeader {
             state_root: spec.zero_hash,
             signature: spec.empty_signature.clone(),
-            ..self.into_header()
+            ..self.block_header()
         }
     }
 }

eth2/types/src/beacon_state/epoch_cache.rs

@@ -107,6 +107,7 @@ impl EpochCache {
         })
     }
 
+    /// Return a vec of `CrosslinkCommittee` for a given slot.
     pub fn get_crosslink_committees_at_slot(
         &self,
         slot: Slot,
@@ -116,6 +117,8 @@ impl EpochCache {
             .get_crosslink_committees_at_slot(slot, spec)
     }
 
+    /// Return `Some(CrosslinkCommittee)` if the given shard has a committee during the given
+    /// `epoch`.
     pub fn get_crosslink_committee_for_shard(
         &self,
         shard: Shard,
@@ -131,6 +134,10 @@ impl EpochCache {
     }
 }
 
+/// Returns a list of all `validator_registry` indices where the validator is active at the given
+/// `epoch`.
+///
+/// Spec v0.5.0
 pub fn get_active_validator_indices(validators: &[Validator], epoch: Epoch) -> Vec<usize> {
     let mut active = Vec::with_capacity(validators.len());
 
@@ -145,13 +152,17 @@ pub fn get_active_validator_indices(validators: &[Validator], epoch: Epoch) -> V
     active
 }
 
+/// Contains all `CrosslinkCommittees` for an epoch.
 #[derive(Debug, Default, PartialEq, Clone, Serialize, Deserialize)]
 pub struct EpochCrosslinkCommittees {
+    /// The epoch the committees are present in.
     epoch: Epoch,
+    /// Each commitee for each slot of the epoch.
     pub crosslink_committees: Vec<Vec<CrosslinkCommittee>>,
 }
 
 impl EpochCrosslinkCommittees {
+    /// Return a new instances where all slots have zero committees.
     fn new(epoch: Epoch, spec: &ChainSpec) -> Self {
         Self {
             epoch,
@@ -159,6 +170,7 @@ impl EpochCrosslinkCommittees {
         }
     }
 
+    /// Return a vec of `CrosslinkCommittee` for a given slot.
     fn get_crosslink_committees_at_slot(
         &self,
         slot: Slot,
@@ -176,6 +188,7 @@ impl EpochCrosslinkCommittees {
     }
 }
 
+/// Builds an `EpochCrosslinkCommittees` object.
 pub struct EpochCrosslinkCommitteesBuilder {
     epoch: Epoch,
     shuffling_start_shard: Shard,
@@ -185,6 +198,7 @@ pub struct EpochCrosslinkCommitteesBuilder {
 }
 
 impl EpochCrosslinkCommitteesBuilder {
+    /// Instantiates a builder that will build for the `state`'s previous epoch.
     pub fn for_previous_epoch(
         state: &BeaconState,
         active_validator_indices: Vec<usize>,
@@ -199,6 +213,7 @@ impl EpochCrosslinkCommitteesBuilder {
         }
     }
 
+    /// Instantiates a builder that will build for the `state`'s next epoch.
     pub fn for_current_epoch(
         state: &BeaconState,
         active_validator_indices: Vec<usize>,
@@ -213,6 +228,10 @@ impl EpochCrosslinkCommitteesBuilder {
         }
     }
 
+    /// Instantiates a builder that will build for the `state`'s next epoch.
+    ///
+    /// Note: there are two possible epoch builds for the next epoch, one where there is a registry
+    /// change and one where there is not.
     pub fn for_next_epoch(
         state: &BeaconState,
         active_validator_indices: Vec<usize>,
@@ -257,6 +276,7 @@ impl EpochCrosslinkCommitteesBuilder {
         })
     }
 
+    /// Consumes the builder, returning a fully-build `EpochCrosslinkCommittee`.
     pub fn build(self, spec: &ChainSpec) -> Result<EpochCrosslinkCommittees, Error> {
         // The shuffler fails on a empty list, so if there are no active validator indices, simply
         // return an empty list.
@@ -284,7 +304,6 @@ impl EpochCrosslinkCommitteesBuilder {
 
         for (i, slot) in self.epoch.slot_iter(spec.slots_per_epoch).enumerate() {
             for j in (0..committees.len())
-                .into_iter()
                 .skip(i * committees_per_slot)
                 .take(committees_per_slot)
             {

eth2/types/src/beacon_state/epoch_cache/tests.rs

@@ -7,15 +7,19 @@ use swap_or_not_shuffle::shuffle_list;
 fn do_sane_cache_test(
     state: BeaconState,
     epoch: Epoch,
+    relative_epoch: RelativeEpoch,
     validator_count: usize,
     expected_seed: Hash256,
     expected_shuffling_start: u64,
     spec: &ChainSpec,
 ) {
     let active_indices: Vec<usize> = (0..validator_count).collect();
+
     assert_eq!(
         &active_indices[..],
-        state.get_active_validator_indices(epoch, &spec).unwrap(),
+        state
+            .get_cached_active_validator_indices(relative_epoch, &spec)
+            .unwrap(),
         "Validator indices mismatch"
     );
 
@@ -101,6 +105,7 @@ fn builds_sane_current_epoch_cache() {
     do_sane_cache_test(
         state.clone(),
         state.current_epoch(&spec),
+        RelativeEpoch::Current,
         validator_count as usize,
         state.current_shuffling_seed,
         state.current_shuffling_start_shard,
@@ -117,6 +122,7 @@ fn builds_sane_previous_epoch_cache() {
     do_sane_cache_test(
         state.clone(),
         state.previous_epoch(&spec),
+        RelativeEpoch::Previous,
         validator_count as usize,
         state.previous_shuffling_seed,
         state.previous_shuffling_start_shard,
@@ -134,6 +140,7 @@ fn builds_sane_next_without_update_epoch_cache() {
     do_sane_cache_test(
         state.clone(),
         state.next_epoch(&spec),
+        RelativeEpoch::NextWithoutRegistryChange,
         validator_count as usize,
         state.current_shuffling_seed,
         state.current_shuffling_start_shard,

eth2/types/src/beacon_state/pubkey_cache.rs

@@ -6,13 +6,17 @@ type ValidatorIndex = usize;
 
 #[derive(Debug, PartialEq, Clone, Default, Serialize, Deserialize)]
 pub struct PubkeyCache {
+    /// Maintain the number of keys added to the map. It is not sufficient to just use the HashMap
+    /// len, as it does not increase when duplicate keys are added. Duplicate keys are used during
+    /// testing.
+    len: usize,
     map: HashMap<PublicKey, ValidatorIndex>,
 }
 
 impl PubkeyCache {
-    /// Returns the number of validator indices already in the map.
+    /// Returns the number of validator indices added to the map so far.
     pub fn len(&self) -> ValidatorIndex {
-        self.map.len()
+        self.len
     }
 
     /// Inserts a validator index into the map.
@@ -20,8 +24,9 @@ impl PubkeyCache {
     /// The added index must equal the number of validators already added to the map. This ensures
     /// that an index is never skipped.
     pub fn insert(&mut self, pubkey: PublicKey, index: ValidatorIndex) -> bool {
-        if index == self.map.len() {
+        if index == self.len {
             self.map.insert(pubkey, index);
+            self.len += 1;
             true
         } else {
             false

eth2/types/src/chain_spec.rs

@@ -124,7 +124,7 @@ pub struct ChainSpec {
 impl ChainSpec {
     /// Return the number of committees in one epoch.
     ///
-    /// Spec v0.4.0
+    /// Spec v0.5.0
     pub fn get_epoch_committee_count(&self, active_validator_count: usize) -> u64 {
         std::cmp::max(
             1,

eth2/types/src/lib.rs

@@ -34,7 +34,6 @@ pub mod relative_epoch;
 pub mod slot_epoch;
 pub mod slot_height;
 pub mod validator;
-pub mod validator_registry;
 
 use ethereum_types::{H160, H256, U256};
 use std::collections::HashMap;

eth2/types/src/relative_epoch.rs

@@ -33,7 +33,7 @@ impl RelativeEpoch {
     /// Returns the `epoch` that `self` refers to, with respect to the `base` epoch.
     ///
     /// Spec v0.5.0
-    pub fn into_epoch(&self, base: Epoch) -> Epoch {
+    pub fn into_epoch(self, base: Epoch) -> Epoch {
         match self {
             RelativeEpoch::Previous => base - 1,
             RelativeEpoch::Current => base,

eth2/types/src/test_utils/testing_beacon_state_builder.rs

@@ -214,7 +214,7 @@ impl TestingBeaconStateBuilder {
             - spec.min_attestation_inclusion_delay;
         let last_slot = std::cmp::min(state.slot.as_u64(), last_slot);
 
-        for slot in first_slot..last_slot + 1 {
+        for slot in first_slot..=last_slot {
             let slot = Slot::from(slot);
 
             let committees = state

eth2/types/src/test_utils/testing_deposit_builder.rs

@@ -47,7 +47,7 @@ impl TestingDepositBuilder {
         self.deposit
             .deposit_data
             .deposit_input
-            .withdrawal_credentials = withdrawal_credentials.clone();
+            .withdrawal_credentials = withdrawal_credentials;
 
         self.deposit.deposit_data.deposit_input.proof_of_possession = self
             .deposit

eth2/types/src/transfer.rs

@@ -9,7 +9,7 @@ use test_random_derive::TestRandom;
 
 /// The data submitted to the deposit contract.
 ///
-/// Spec v0.4.0
+/// Spec v0.5.0
 #[derive(
     Debug,
     PartialEq,

eth2/types/src/validator_registry.rs

@@ -1,174 +0,0 @@
-/// Contains logic to manipulate a `&[Validator]`.
-/// For now, we avoid defining a newtype and just have flat functions here.
-use super::validator::*;
-use crate::Epoch;
-
-/// Given an indexed sequence of `validators`, return the indices corresponding to validators that are active at `epoch`.
-///
-/// Spec v0.4.0
-pub fn get_active_validator_indices(validators: &[Validator], epoch: Epoch) -> Vec<usize> {
-    let mut active = Vec::with_capacity(validators.len());
-
-    for (index, validator) in validators.iter().enumerate() {
-        if validator.is_active_at(epoch) {
-            active.push(index)
-        }
-    }
-
-    active.shrink_to_fit();
-
-    active
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-
-    #[test]
-    fn can_get_empty_active_validator_indices() {
-        let mut rng = XorShiftRng::from_seed([42; 16]);
-
-        let validators = vec![];
-        let some_epoch = Epoch::random_for_test(&mut rng);
-        let indices = get_active_validator_indices(&validators, some_epoch);
-        assert_eq!(indices, vec![]);
-    }
-
-    #[test]
-    fn can_get_no_active_validator_indices() {
-        let mut rng = XorShiftRng::from_seed([42; 16]);
-        let mut validators = vec![];
-        let count_validators = 10;
-        for _ in 0..count_validators {
-            validators.push(Validator::default())
-        }
-
-        let some_epoch = Epoch::random_for_test(&mut rng);
-        let indices = get_active_validator_indices(&validators, some_epoch);
-        assert_eq!(indices, vec![]);
-    }
-
-    #[test]
-    fn can_get_all_active_validator_indices() {
-        let mut rng = XorShiftRng::from_seed([42; 16]);
-        let count_validators = 10;
-        let some_epoch = Epoch::random_for_test(&mut rng);
-
-        let mut validators = (0..count_validators)
-            .into_iter()
-            .map(|_| {
-                let mut validator = Validator::default();
-
-                let activation_offset = u64::random_for_test(&mut rng);
-                let exit_offset = u64::random_for_test(&mut rng);
-
-                validator.activation_epoch = some_epoch - activation_offset;
-                validator.exit_epoch = some_epoch + exit_offset;
-
-                validator
-            })
-            .collect::<Vec<_>>();
-
-        // test boundary condition by ensuring that at least one validator in the list just activated
-        if let Some(validator) = validators.get_mut(0) {
-            validator.activation_epoch = some_epoch;
-        }
-
-        let indices = get_active_validator_indices(&validators, some_epoch);
-        assert_eq!(
-            indices,
-            (0..count_validators).into_iter().collect::<Vec<_>>()
-        );
-    }
-
-    fn set_validators_to_default_entry_exit(validators: &mut [Validator]) {
-        for validator in validators.iter_mut() {
-            validator.activation_epoch = Epoch::max_value();
-            validator.exit_epoch = Epoch::max_value();
-        }
-    }
-
-    // sets all `validators` to be active as of some epoch prior to `epoch`. returns the activation epoch.
-    fn set_validators_to_activated(validators: &mut [Validator], epoch: Epoch) -> Epoch {
-        let activation_epoch = epoch - 10;
-        for validator in validators.iter_mut() {
-            validator.activation_epoch = activation_epoch;
-        }
-        activation_epoch
-    }
-
-    // sets all `validators` to be exited as of some epoch before `epoch`.
-    fn set_validators_to_exited(
-        validators: &mut [Validator],
-        epoch: Epoch,
-        activation_epoch: Epoch,
-    ) {
-        assert!(activation_epoch < epoch);
-        let mut exit_epoch = activation_epoch + 10;
-        while exit_epoch >= epoch {
-            exit_epoch -= 1;
-        }
-        assert!(activation_epoch < exit_epoch && exit_epoch < epoch);
-
-        for validator in validators.iter_mut() {
-            validator.exit_epoch = exit_epoch;
-        }
-    }
-
-    #[test]
-    fn can_get_some_active_validator_indices() {
-        let mut rng = XorShiftRng::from_seed([42; 16]);
-        const COUNT_PARTITIONS: usize = 3;
-        const COUNT_VALIDATORS: usize = 3 * COUNT_PARTITIONS;
-        let some_epoch: Epoch = Epoch::random_for_test(&mut rng);
-
-        let mut validators = (0..COUNT_VALIDATORS)
-            .into_iter()
-            .map(|_| {
-                let mut validator = Validator::default();
-
-                let activation_offset = Epoch::random_for_test(&mut rng);
-                let exit_offset = Epoch::random_for_test(&mut rng);
-
-                validator.activation_epoch = some_epoch - activation_offset;
-                validator.exit_epoch = some_epoch + exit_offset;
-
-                validator
-            })
-            .collect::<Vec<_>>();
-
-        // we partition the set into partitions based on lifecycle:
-        for (i, chunk) in validators.chunks_exact_mut(COUNT_PARTITIONS).enumerate() {
-            match i {
-                0 => {
-                    // 1. not activated (Default::default())
-                    set_validators_to_default_entry_exit(chunk);
-                }
-                1 => {
-                    // 2. activated, but not exited
-                    set_validators_to_activated(chunk, some_epoch);
-                    // test boundary condition by ensuring that at least one validator in the list just activated
-                    if let Some(validator) = chunk.get_mut(0) {
-                        validator.activation_epoch = some_epoch;
-                    }
-                }
-                2 => {
-                    // 3. exited
-                    let activation_epoch = set_validators_to_activated(chunk, some_epoch);
-                    set_validators_to_exited(chunk, some_epoch, activation_epoch);
-                    // test boundary condition by ensuring that at least one validator in the list just exited
-                    if let Some(validator) = chunk.get_mut(0) {
-                        validator.exit_epoch = some_epoch;
-                    }
-                }
-                _ => unreachable!(
-                    "constants local to this test not in sync with generation of test case"
-                ),
-            }
-        }
-
-        let indices = get_active_validator_indices(&validators, some_epoch);
-        assert_eq!(indices, vec![3, 4, 5]);
-    }
-}