adjust get_shuffling and get_active_validator_indices to use slot, per spec

beacon_chain/spec/beaconstate.nim

@@ -295,7 +295,7 @@ func get_initial_beacon_state*(
   # set initial committee shuffling
   let
     initial_shuffling =
-      get_shuffling(Eth2Digest(), state.validator_registry, 0)
+      get_shuffling(Eth2Digest(), state.validator_registry, 0, state.slot)
 
   # initial_shuffling + initial_shuffling in spec, but more ugly
   for i, n in initial_shuffling:
@@ -304,7 +304,7 @@ func get_initial_beacon_state*(
 
   # set initial persistent shuffling
   let active_validator_indices =
-    get_active_validator_indices(state.validator_registry)
+    get_active_validator_indices(state.validator_registry, state.slot)
 
   state.persistent_committees = split(shuffle(
     active_validator_indices, ZERO_HASH), SHARD_COUNT)
@@ -353,14 +353,14 @@ func process_ejections*(state: var BeaconState) =
   ## Iterate through the validator registry
   ## and eject active validators with balance below ``EJECTION_BALANCE``.
 
-  for index in get_active_validator_indices(state.validator_registry):
+  for index in get_active_validator_indices(state.validator_registry, state.slot):
     if state.validator_balances[index] < EJECTION_BALANCE:
       exit_validator(state, index, EXITED_WITHOUT_PENALTY)
 
 func update_validator_registry*(state: var BeaconState) =
   let
     active_validator_indices =
-      get_active_validator_indices(state.validator_registry)
+      get_active_validator_indices(state.validator_registry, state.slot)
     # The total effective balance of active validators
     total_balance = sum_effective_balances(state, active_validator_indices)
 

beacon_chain/spec/helpers.nim

@@ -185,14 +185,13 @@ proc is_surround_vote*(attestation_data_1: AttestationData,
 #  ### Checks if validator is active
 #  validator.activation_slot <= slot and slot < validator.exit_slot
 
-func is_active_validator*(validator: Validator): bool =
+func is_active_validator*(validator: Validator, slot: uint64): bool =
   validator.status in {ACTIVE, ACTIVE_PENDING_EXIT}
 
 func get_active_validator_indices*(validators: openArray[Validator], slot: uint64): seq[Uint24] =
   ## Gets indices of active validators from validators
   for idx, val in validators:
-    #if is_active_validator(val, slot):
+    if is_active_validator(val, slot):
-    if is_active_validator(val):
       result.add idx.Uint24
 
 func get_committee_count_per_slot*(active_validator_count: int): uint64 =

beacon_chain/spec/validator.nim

@@ -22,22 +22,18 @@ func min_empty_validator_index*(
           ZERO_BALANCE_VALIDATOR_TTL.uint64 <= current_slot:
       return some(i)
 
-func get_active_validator_indices*(validators: openArray[Validator]): seq[Uint24] =
-  ## Select the active validators
-  for idx, val in validators:
-    if is_active_validator(val):
-      result.add idx.Uint24
-
 func get_shuffling*(seed: Eth2Digest,
                     validators: openArray[Validator],
-                    crosslinking_start_shard: uint64
+                    crosslinking_start_shard: uint64, # TODO remove
+                    slot_nonaligned: uint64
                     ): array[EPOCH_LENGTH, seq[ShardCommittee]] =
   ## Split up validators into groups at the start of every epoch,
   ## determining at what height they can make attestations and what shard they are making crosslinks for
   ## Implementation should do the following: http://vitalik.ca/files/ShuffleAndAssign.png
 
   let
-    active_validator_indices = get_active_validator_indices(validators)
+    slot = slot_nonaligned - slot_nonaligned mod EPOCH_LENGTH
+    active_validator_indices = get_active_validator_indices(validators, slot)
     committees_per_slot = clamp(
       len(active_validator_indices) div EPOCH_LENGTH div TARGET_COMMITTEE_SIZE,
       1, SHARD_COUNT div EPOCH_LENGTH).uint64

beacon_chain/state_transition.nim

@@ -304,7 +304,6 @@ proc processExits(
       warn("Exit: bad slot")
       return false
 
-    exit_validator(state, exit.validator_index, ACTIVE_PENDING_EXIT)
     initiate_validator_exit(state, exit.validator_index)
 
   return true
@@ -316,7 +315,7 @@ proc process_ejections(state: var BeaconState) =
   ## https://github.com/ethereum/eth2.0-specs/blob/master/specs/core/0_beacon-chain.md#ejections
 
   for index, validator in state.validator_registry:
-    if is_active_validator(validator) and
+    if is_active_validator(validator, state.slot) and
         state.validator_balances[index] < EJECTION_BALANCE:
       exit_validator(state, index.Uint24, EXITED_WITHOUT_PENALTY)
 
@@ -443,7 +442,7 @@ func processEpoch(state: var BeaconState) =
   # Precomputation
   let
     active_validator_indices =
-      get_active_validator_indices(state.validator_registry)
+      get_active_validator_indices(state.validator_registry, state.slot)
     total_balance = sum_effective_balances(state, active_validator_indices)
     total_balance_in_eth = total_balance div GWEI_PER_ETH
 
@@ -714,7 +713,7 @@ func processEpoch(state: var BeaconState) =
       for i, v in get_shuffling(
           state.latest_randao_mixes[
             (state.slot - EPOCH_LENGTH) mod LATEST_RANDAO_MIXES_LENGTH],
-          state.validator_registry, next_start_shard):
+          state.validator_registry, next_start_shard, state.slot):
         state.shard_committees_at_slots[i + EPOCH_LENGTH] = v
 
     else:
@@ -733,7 +732,7 @@ func processEpoch(state: var BeaconState) =
         for i, v in get_shuffling(
             state.latest_randao_mixes[
               (state.slot - EPOCH_LENGTH) mod LATEST_RANDAO_MIXES_LENGTH],
-            state.validator_registry, start_shard):
+            state.validator_registry, start_shard, state.slot):
           state.shard_committees_at_slots[i + EPOCH_LENGTH] = v
         # Note that `start_shard` is not changed from the last epoch.
 

tests/test_validator.nim

@@ -25,7 +25,7 @@ suite "Validators":
         ), 32*1024)
 
     # TODO the shuffling looks really odd, probably buggy
-    let s = get_shuffling(Eth2Digest(), validators, 0)
+    let s = get_shuffling(Eth2Digest(), validators, 0, 0)
     check:
       s.len == EPOCH_LENGTH
        # 32k validators means 2 shards validated per slot - the aim is to get