From aca3e4cd5cef9a660d0c4e07db0e5b82bf6e9084 Mon Sep 17 00:00:00 2001
From: tersec <tersec@users.noreply.github.com>
Date: Sun, 14 Feb 2021 19:31:01 +0000
Subject: [PATCH] per HF1, split process_final_updates() (#2319)

---
 beacon_chain/spec/state_transition_epoch.nim | 39 +++++++++++++++++---
 1 file changed, 33 insertions(+), 6 deletions(-)

diff --git a/beacon_chain/spec/state_transition_epoch.nim b/beacon_chain/spec/state_transition_epoch.nim
index a06061cb7..0a91f46e0 100644
--- a/beacon_chain/spec/state_transition_epoch.nim
+++ b/beacon_chain/spec/state_transition_epoch.nim
@@ -1,5 +1,5 @@
 # beacon_chain
-# Copyright (c) 2018-2020 Status Research & Development GmbH
+# Copyright (c) 2018-2021 Status Research & Development GmbH
 # Licensed and distributed under either of
 #   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
 #   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
@@ -544,16 +544,16 @@ func process_slashings*(state: var BeaconState, total_balance: Gwei) {.nbench.}=
       let penalty = penalty_numerator div total_balance * increment
       decrease_balance(state, index.ValidatorIndex, penalty)
 
-# https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#final-updates
-func process_final_updates*(state: var BeaconState) {.nbench.}=
-  let
-    current_epoch = get_current_epoch(state)
-    next_epoch = current_epoch + 1
+# https://github.com/ethereum/eth2.0-specs/blob/dev/specs/phase0/beacon-chain.md#eth1-data-votes-updates
+func process_eth1_data_reset(state: var BeaconState) {.nbench.} =
+  let next_epoch = get_current_epoch(state) + 1
 
   # Reset eth1 data votes
   if next_epoch mod EPOCHS_PER_ETH1_VOTING_PERIOD == 0:
     state.eth1_data_votes = default(type state.eth1_data_votes)
 
+# https://github.com/ethereum/eth2.0-specs/blob/dev/specs/phase0/beacon-chain.md#effective-balances-updates
+func process_effective_balance_updates(state: var BeaconState) {.nbench.} =
   # Update effective balances with hysteresis
   for index in 0..<state.validators.len:
     let balance = state.balances.asSeq()[index]
@@ -571,14 +571,28 @@ func process_final_updates*(state: var BeaconState) {.nbench.}=
           balance - balance mod EFFECTIVE_BALANCE_INCREMENT,
           MAX_EFFECTIVE_BALANCE)
 
+# https://github.com/ethereum/eth2.0-specs/blob/dev/specs/phase0/beacon-chain.md#slashings-balances-updates
+func process_slashings_reset(state: var BeaconState) {.nbench.} =
+  let next_epoch = get_current_epoch(state) + 1
+
   # Reset slashings
   state.slashings[int(next_epoch mod EPOCHS_PER_SLASHINGS_VECTOR)] = 0.Gwei
 
+# https://github.com/ethereum/eth2.0-specs/blob/dev/specs/phase0/beacon-chain.md#randao-mixes-updates
+func process_randao_mixes_reset(state: var BeaconState) {.nbench.} =
+  let
+    current_epoch = get_current_epoch(state)
+    next_epoch = current_epoch + 1
+
   # Set randao mix
   state.randao_mixes[next_epoch mod EPOCHS_PER_HISTORICAL_VECTOR] =
     get_randao_mix(state, current_epoch)
 
+# https://github.com/ethereum/eth2.0-specs/blob/dev/specs/phase0/beacon-chain.md#historical-roots-updates
+func process_historical_roots_update(state: var BeaconState) {.nbench.} =
   # Set historical root accumulator
+  let next_epoch = get_current_epoch(state) + 1
+
   if next_epoch mod (SLOTS_PER_HISTORICAL_ROOT div SLOTS_PER_EPOCH) == 0:
     # Equivalent to hash_tree_root(foo: HistoricalBatch), but without using
     # significant additional stack or heap.
@@ -587,11 +601,24 @@ func process_final_updates*(state: var BeaconState) {.nbench.}=
     state.historical_roots.add hash_tree_root(
       [hash_tree_root(state.block_roots), hash_tree_root(state.state_roots)])
 
+# https://github.com/ethereum/eth2.0-specs/blob/dev/specs/phase0/beacon-chain.md#participation-records-rotation
+func process_participation_record_updates(state: var BeaconState) {.nbench.} =
   # Rotate current/previous epoch attestations - using swap avoids copying all
   # elements using a slow genericSeqAssign
   state.previous_epoch_attestations.clear()
   swap(state.previous_epoch_attestations, state.current_epoch_attestations)
 
+# https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#final-updates
+func process_final_updates*(state: var BeaconState) {.nbench.} =
+  # This function's a wrapper over the HF1 split/refactored HF1 version. TODO
+  # remove once test vectors become available for each HF1 function.
+  process_eth1_data_reset(state)
+  process_effective_balance_updates(state)
+  process_slashings_reset(state)
+  process_randao_mixes_reset(state)
+  process_historical_roots_update(state)
+  process_participation_record_updates(state)
+
 # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#epoch-processing
 proc process_epoch*(state: var BeaconState, updateFlags: UpdateFlags,
     cache: var StateCache) {.nbench.} =