Update to spec v0.8.3

eth2/state_processing/src/common/get_attesting_indices.rs

@@ -17,11 +17,9 @@ pub fn get_attesting_indices<T: EthSpec>(
         target_relative_epoch,
     )?;
 
-    /* TODO(freeze): re-enable this?
+    if bitlist.len() != committee.committee.len() {
-    if bitlist.len() > committee.committee.len() {
         return Err(BeaconStateError::InvalidBitfield);
     }
-    */
 
     Ok(committee
         .committee

eth2/state_processing/src/common/get_compact_committees_root.rs

@@ -3,7 +3,7 @@ use types::*;
 
 /// Return the compact committee root at `relative_epoch`.
 ///
-/// Spec v0.8.0
+/// Spec v0.8.3
 pub fn get_compact_committees_root<T: EthSpec>(
     state: &BeaconState<T>,
     relative_epoch: RelativeEpoch,
@@ -11,28 +11,13 @@ pub fn get_compact_committees_root<T: EthSpec>(
 ) -> Result<Hash256, BeaconStateError> {
     let mut committees =
         FixedVector::<_, T::ShardCount>::from_elem(CompactCommittee::<T>::default());
-    // FIXME: this is a spec bug, whereby the start shard for the epoch after the next epoch
+    let start_shard = state.get_epoch_start_shard(relative_epoch)?;
-    // is mistakenly used. The start shard from the cache SHOULD work.
-    // Waiting on a release to fix https://github.com/ethereum/eth2.0-specs/issues/1315
-    let start_shard = if relative_epoch == RelativeEpoch::Next {
-        state.next_epoch_start_shard(spec)?
-    } else {
-        state.get_epoch_start_shard(relative_epoch)?
-    };
 
     for committee_number in 0..state.get_committee_count(relative_epoch)? {
         let shard = (start_shard + committee_number) % T::ShardCount::to_u64();
-        // FIXME: this is a partial workaround for the above, but it only works in the case
-        // where there's a committee for every shard in every epoch. It works for the minimal
-        // tests but not the mainnet ones.
-        let fake_shard = if relative_epoch == RelativeEpoch::Next {
-            (shard + 1) % T::ShardCount::to_u64()
-        } else {
-            shard
-        };
 
         for &index in state
-            .get_crosslink_committee_for_shard(fake_shard, relative_epoch)?
+            .get_crosslink_committee_for_shard(shard, relative_epoch)?
             .committee
         {
             let validator = state

eth2/state_processing/src/common/get_indexed_attestation.rs

@@ -11,6 +11,8 @@ pub fn get_indexed_attestation<T: EthSpec>(
     state: &BeaconState<T>,
     attestation: &Attestation<T>,
 ) -> Result<IndexedAttestation<T>, Error> {
+    // Note: we rely on both calls to `get_attesting_indices` to check the bitfield lengths
+    // against the committee length
     let attesting_indices =
         get_attesting_indices(state, &attestation.data, &attestation.aggregation_bits)?;
 

eth2/state_processing/src/per_epoch_processing.rs

@@ -218,9 +218,6 @@ pub fn process_final_updates<T: EthSpec>(
         }
     }
 
-    // Update start shard.
-    state.start_shard = state.next_epoch_start_shard(spec)?;
-
     // Set active index root
     let index_epoch = next_epoch + spec.activation_exit_delay;
     let indices_list = VariableList::<usize, T::ValidatorRegistryLimit>::from(
@@ -252,6 +249,9 @@ pub fn process_final_updates<T: EthSpec>(
             .push(Hash256::from_slice(&historical_batch.tree_hash_root()))?;
     }
 
+    // Update start shard.
+    state.start_shard = state.get_epoch_start_shard(RelativeEpoch::Next)?;
+
     // Rotate current/previous epoch attestations
     state.previous_epoch_attestations =
         std::mem::replace(&mut state.current_epoch_attestations, VariableList::empty());

eth2/types/src/beacon_state.rs

@@ -298,14 +298,6 @@ impl<T: EthSpec> BeaconState<T> {
         Ok(cache.epoch_start_shard())
     }
 
-    pub fn next_epoch_start_shard(&self, spec: &ChainSpec) -> Result<u64, Error> {
-        let cache = self.cache(RelativeEpoch::Current)?;
-        let active_validator_count = cache.active_validator_count();
-        let shard_delta = T::get_shard_delta(active_validator_count, spec.target_committee_size);
-
-        Ok((self.start_shard + shard_delta) % T::ShardCount::to_u64())
-    }
-
     /// Get the slot of an attestation.
     ///
     /// Note: Utilizes the cache and will fail if the appropriate cache is not initialized.