feat: electra process_registry_updates & slash_validators changes (#1420)

Author: LeanSerra

config/networks/mainnet/config.yaml

@@ -151,3 +151,9 @@ WHISK_PROPOSER_SELECTION_GAP: 2
 # EIP7594
 EIP7594_FORK_VERSION: 0x06000001
 EIP7594_FORK_EPOCH: 18446744073709551615
+
+# Electra
+# 2**7 * 10**9 (= 128,000,000,000) Gwei
+MIN_PER_EPOCH_CHURN_LIMIT_ELECTRA: 128000000000
+# 2**8 * 10**9) (= 256,000,000,000) Gwei
+MAX_PER_EPOCH_ACTIVATION_EXIT_CHURN_LIMIT: 256000000000

config/networks/minimal/config.yaml

@@ -149,3 +149,9 @@ WHISK_PROPOSER_SELECTION_GAP: 1
 # EIP7594
 EIP7594_FORK_VERSION: 0x06000001
 EIP7594_FORK_EPOCH: 18446744073709551615
+
+# Electra
+# [customized] 2**7 * 10**9 (= 128,000,000,000) Gwei
+MIN_PER_EPOCH_CHURN_LIMIT_ELECTRA: 64000000000
+# [customized] 2**8 * 10**9) (= 256,000,000,000) Gwei
+MAX_PER_EPOCH_ACTIVATION_EXIT_CHURN_LIMIT: 128000000000

config/presets/mainnet/electra.yaml

@@ -47,4 +47,4 @@ MAX_PENDING_PARTIALS_PER_WITHDRAWALS_SWEEP: 8
 # Pending deposits processing
 # ---------------------------------------------------------------
 # 2**4 ( = 4) pending deposits
-MAX_PENDING_DEPOSITS_PER_EPOCH: 16
+MAX_PENDING_DEPOSITS_PER_EPOCH: 16

config/presets/minimal/electra.yaml

@@ -47,4 +47,4 @@ MAX_PENDING_PARTIALS_PER_WITHDRAWALS_SWEEP: 2
 # Pending deposits processing
 # ---------------------------------------------------------------
 # 2**4 ( = 4) pending deposits
-MAX_PENDING_DEPOSITS_PER_EPOCH: 16
+MAX_PENDING_DEPOSITS_PER_EPOCH: 16

lib/lambda_ethereum_consensus/state_transition/accessors.ex

@@ -657,4 +657,29 @@ defmodule LambdaEthereumConsensus.StateTransition.Accessors do
 
     for {bit, index} <- Enum.with_index(bitlist), bit == 1, do: index
   end
+
+  @doc """
+  Return the churn limit for the current epoch.
+  """
+  @spec get_balance_churn_limit(Types.BeaconState.t()) :: Types.gwei()
+  def get_balance_churn_limit(state) do
+    churn =
+      max(
+        ChainSpec.get("MIN_PER_EPOCH_CHURN_LIMIT_ELECTRA"),
+        div(get_total_active_balance(state), ChainSpec.get("CHURN_LIMIT_QUOTIENT"))
+      )
+
+    churn - rem(churn, ChainSpec.get("EFFECTIVE_BALANCE_INCREMENT"))
+  end
+
+  @doc """
+  Return the churn limit for the current epoch dedicated to activations and exits.
+  """
+  @spec get_activation_exit_churn_limit(Types.BeaconState.t()) :: Types.gwei()
+  def get_activation_exit_churn_limit(state) do
+    min(
+      ChainSpec.get("MAX_PER_EPOCH_ACTIVATION_EXIT_CHURN_LIMIT"),
+      get_balance_churn_limit(state)
+    )
+  end
 end

lib/lambda_ethereum_consensus/state_transition/epoch_processing.ex

@@ -144,49 +144,75 @@ defmodule LambdaEthereumConsensus.StateTransition.EpochProcessing do
     current_epoch = Accessors.get_current_epoch(state)
     activation_exit_epoch = Misc.compute_activation_exit_epoch(current_epoch)
 
-    churn_limit = Accessors.get_validator_activation_churn_limit(state)
+    validators
+    |> Enum.with_index()
+    |> Enum.reduce_while(state, fn {validator, idx}, state ->
+      handle_validator_registry_update(
+        state,
+        validator,
+        idx,
+        current_epoch,
+        activation_exit_epoch,
+        ejection_balance
+      )
+    end)
+    |> then(fn
+      %BeaconState{} = state -> {:ok, state}
+      {:error, reason} -> {:error, reason}
+    end)
+  end
 
-    result =
-      validators
-      |> Stream.with_index()
-      |> Stream.map(fn {v, i} ->
-        {{v, i}, Predicates.eligible_for_activation_queue?(v),
-         Predicates.active_validator?(v, current_epoch) and
-           v.effective_balance <= ejection_balance}
-      end)
-      |> Stream.filter(&(elem(&1, 1) or elem(&1, 2)))
-      |> Stream.map(fn
-        {{v, i}, true, b} -> {{%{v | activation_eligibility_epoch: current_epoch + 1}, i}, b}
-        {{v, i}, false = _is_eligible, b} -> {{v, i}, b}
-      end)
-      |> Enum.reduce({:ok, state}, fn
-        _, {:error, _} = err -> err
-        {{v, i}, should_be_ejected}, {:ok, st} -> eject_validator(st, v, i, should_be_ejected)
-        {err, _}, _ -> err
-      end)
+  defp handle_validator_registry_update(
+         state,
+         validator,
+         idx,
+         current_epoch,
+         activation_exit_epoch,
+         ejection_balance
+       ) do
+    cond do
+      Predicates.eligible_for_activation_queue?(validator) ->
+        updated_validator = %Validator{
+          validator
+          | activation_eligibility_epoch: current_epoch + 1
+        }
 
-    with {:ok, new_state} <- result do
-      new_state.validators
-      |> Stream.with_index()
-      |> Stream.filter(fn {v, _} -> Predicates.eligible_for_activation?(state, v) end)
-      |> Enum.sort_by(fn {%{activation_eligibility_epoch: ep}, i} -> {ep, i} end)
-      |> Enum.take(churn_limit)
-      |> Enum.reduce(new_state.validators, fn {v, i}, acc ->
-        %{v | activation_epoch: activation_exit_epoch}
-        |> then(&Aja.Vector.replace_at!(acc, i, &1))
-      end)
-      |> then(&{:ok, %BeaconState{new_state | validators: &1}})
-    end
-  end
+        {:cont,
+         %BeaconState{
+           state
+           | validators: Aja.Vector.replace_at!(state.validators, idx, updated_validator)
+         }}
 
-  defp eject_validator(state, validator, index, false) do
-    {:ok, %{state | validators: Aja.Vector.replace_at!(state.validators, index, validator)}}
-  end
+      Predicates.active_validator?(validator, current_epoch) &&
+          validator.effective_balance <= ejection_balance ->
+        case Mutators.initiate_validator_exit(state, validator) do
+          {:ok, {state, ejected_validator}} ->
+            updated_state = %{
+              state
+              | validators: Aja.Vector.replace_at!(state.validators, idx, ejected_validator)
+            }
+
+            {:cont, updated_state}
+
+          {:error, msg} ->
+            {:halt, {:error, msg}}
+        end
+
+      Predicates.eligible_for_activation?(state, validator) ->
+        updated_validator = %Validator{
+          validator
+          | activation_epoch: activation_exit_epoch
+        }
+
+        updated_state = %BeaconState{
+          state
+          | validators: Aja.Vector.replace_at!(state.validators, idx, updated_validator)
+        }
+
+        {:cont, updated_state}
 
-  defp eject_validator(state, validator, index, true) do
-    with {:ok, ejected_validator} <- Mutators.initiate_validator_exit(state, validator) do
-      {:ok,
-       %{state | validators: Aja.Vector.replace_at!(state.validators, index, ejected_validator)}}
+      true ->
+        {:cont, state}
     end
   end
 

lib/lambda_ethereum_consensus/state_transition/mutators.ex

@@ -11,59 +11,33 @@ defmodule LambdaEthereumConsensus.StateTransition.Mutators do
   Initiate the exit of the validator with index ``index``.
   """
   @spec initiate_validator_exit(BeaconState.t(), integer()) ::
-          {:ok, Validator.t()} | {:error, String.t()}
+          {:ok, {BeaconState.t(), Validator.t()}} | {:error, String.t()}
   def initiate_validator_exit(%BeaconState{} = state, index) when is_integer(index) do
     initiate_validator_exit(state, Aja.Vector.at!(state.validators, index))
   end
 
   @spec initiate_validator_exit(BeaconState.t(), Validator.t()) ::
-          {:ok, Validator.t()} | {:error, String.t()}
+          {:ok, {BeaconState.t(), Validator.t()}} | {:error, String.t()}
   def initiate_validator_exit(%BeaconState{} = state, %Validator{} = validator) do
     far_future_epoch = Constants.far_future_epoch()
     min_validator_withdrawability_delay = ChainSpec.get("MIN_VALIDATOR_WITHDRAWABILITY_DELAY")
 
     if validator.exit_epoch != far_future_epoch do
-      {:ok, validator}
+      {:ok, {state, validator}}
     else
-      exit_epochs =
-        state.validators
-        |> Stream.filter(fn validator ->
-          validator.exit_epoch != far_future_epoch
-        end)
-        |> Stream.map(fn validator -> validator.exit_epoch end)
-        |> Enum.to_list()
-
-      exit_queue_epoch =
-        Enum.max(
-          exit_epochs ++ [Misc.compute_activation_exit_epoch(Accessors.get_current_epoch(state))]
-        )
-
-      exit_queue_churn =
-        state.validators
-        |> Stream.filter(fn validator ->
-          validator.exit_epoch == exit_queue_epoch
-        end)
-        |> Enum.to_list()
-        |> length()
-
-      exit_queue_epoch =
-        if exit_queue_churn >= Accessors.get_validator_churn_limit(state) do
-          exit_queue_epoch + 1
-        else
-          exit_queue_epoch
-        end
-
-      next_withdrawable_epoch = exit_queue_epoch + min_validator_withdrawability_delay
+      state = compute_exit_epoch_and_update_churn(state, validator.effective_balance)
+      exit_queue_epoch = state.earliest_exit_epoch
 
-      if next_withdrawable_epoch > Constants.far_future_epoch() do
-        {:error, "withdrawable_epoch_too_large"}
+      if exit_queue_epoch + min_validator_withdrawability_delay > 2 ** 64 do
+        {:error, "withdrawable_epoch overflow"}
       else
         {:ok,
-         %{
-           validator
-           | exit_epoch: exit_queue_epoch,
-             withdrawable_epoch: next_withdrawable_epoch
-         }}
+         {state,
+          %{
+            validator
+            | exit_epoch: exit_queue_epoch,
+              withdrawable_epoch: exit_queue_epoch + min_validator_withdrawability_delay
+          }}}
       end
     end
   end
@@ -78,17 +52,17 @@ defmodule LambdaEthereumConsensus.StateTransition.Mutators do
         ) ::
           {:ok, BeaconState.t()} | {:error, String.t()}
   def slash_validator(state, slashed_index, whistleblower_index \\ nil) do
-    with {:ok, validator} <- initiate_validator_exit(state, slashed_index),
+    with {:ok, {state, validator}} <- initiate_validator_exit(state, slashed_index),
          state = add_slashing(state, validator, slashed_index),
          {:ok, proposer_index} <- Accessors.get_beacon_proposer_index(state) do
       slashing_penalty =
         validator.effective_balance
-        |> div(ChainSpec.get("MIN_SLASHING_PENALTY_QUOTIENT_BELLATRIX"))
+        |> div(ChainSpec.get("MIN_SLASHING_PENALTY_QUOTIENT_ELECTRA"))
 
       whistleblower_index = whistleblower_index(whistleblower_index, proposer_index)
 
       whistleblower_reward =
-        div(validator.effective_balance, ChainSpec.get("WHISTLEBLOWER_REWARD_QUOTIENT"))
+        div(validator.effective_balance, ChainSpec.get("WHISTLEBLOWER_REWARD_QUOTIENT_ELECTRA"))
 
       proposer_reward =
         (whistleblower_reward * Constants.proposer_weight())
@@ -187,4 +161,41 @@ defmodule LambdaEthereumConsensus.StateTransition.Mutators do
     )
     |> then(&{:ok, &1})
   end
+
+  @spec compute_exit_epoch_and_update_churn(Types.BeaconState.t(), Types.gwei()) ::
+          Types.BeaconState.t()
+  def compute_exit_epoch_and_update_churn(state, exit_balance) do
+    current_epoch = Accessors.get_current_epoch(state)
+
+    earliest_exit_epoch =
+      max(state.earliest_exit_epoch, Misc.compute_activation_exit_epoch(current_epoch))
+
+    per_epoch_churn = Accessors.get_activation_exit_churn_limit(state)
+
+    exit_balance_to_consume =
+      if state.earliest_exit_epoch < earliest_exit_epoch do
+        per_epoch_churn
+      else
+        state.exit_balance_to_consume
+      end
+
+    {earliest_exit_epoch, exit_balance_to_consume} =
+      if exit_balance > exit_balance_to_consume do
+        balance_to_process = exit_balance - exit_balance_to_consume
+        additional_epochs = div(balance_to_process - 1, per_epoch_churn) + 1
+
+        {
+          earliest_exit_epoch + additional_epochs,
+          exit_balance_to_consume + additional_epochs * per_epoch_churn
+        }
+      else
+        {earliest_exit_epoch, exit_balance_to_consume}
+      end
+
+    %BeaconState{
+      state
+      | exit_balance_to_consume: exit_balance_to_consume - exit_balance,
+        earliest_exit_epoch: earliest_exit_epoch
+    }
+  end
 end

lib/lambda_ethereum_consensus/state_transition/operations.ex

@@ -571,7 +571,7 @@ defmodule LambdaEthereumConsensus.StateTransition.Operations do
         {:error, "invalid signature"}
 
       true ->
-        with {:ok, validator} <- Mutators.initiate_validator_exit(state, validator_index) do
+        with {:ok, {state, validator}} <- Mutators.initiate_validator_exit(state, validator_index) do
           Aja.Vector.replace_at!(state.validators, validator_index, validator)
           |> then(&{:ok, %BeaconState{state | validators: &1}})
         end