feat: implement electra deposits (#1424)

Author: LeanSerra

electra-gap.md

@@ -62,23 +62,26 @@ This document outlines the gaps in the current implementation of the Electra. It
 - [ ] Modified `process_epoch` ([Spec](docs/specs/electra/beacon-chain.md#modified-process_epoch))
 - [x] Modified `process_registry_updates` ([Spec](docs/specs/electra/beacon-chain.md#modified-process_registry_updates), [PR](https://github.com/lambdaclass/lambda_ethereum_consensus/pull/1420))
 - [x] Modified `process_slashings` ([Spec](docs/specs/electra/beacon-chain.md#modified-process_slashings), [PR](https://github.com/lambdaclass/lambda_ethereum_consensus/pull/1417))
-- [ ] New `apply_pending_deposit` ([Spec](docs/specs/electra/beacon-chain.md#new-apply_pending_deposit))
-- [ ] New `process_pending_deposits` ([Spec](docs/specs/electra/beacon-chain.md#new-process_pending_deposits))
+- [x] New `apply_pending_deposit` ([Spec](docs/specs/electra/beacon-chain.md#new-apply_pending_deposit), [PR](https://github.com/lambdaclass/lambda_ethereum_consensus/pull/1424))
+- [x] New `process_pending_deposits` ([Spec](docs/specs/electra/beacon-chain.md#new-process_pending_deposits), [PR](https://github.com/lambdaclass/lambda_ethereum_consensus/pull/1424))
 - [ ] New `process_pending_consolidations` ([Spec](docs/specs/electra/beacon-chain.md#new-process_pending_consolidations))
 - [ ] Modified `process_effective_balance_updates` ([Spec](docs/specs/electra/beacon-chain.md#modified-process_effective_balance_updates))
+- [x] Modified `get_validator_from_deposit` ([Spec](docs/specs/electra/beacon-chains.md#modified-get_validator_from_deposit), [PR](https://github.com/lambdaclass/lambda_ethereum_consensus/pull/1424))
 
 ## Block Processing
 
 - [ ] Modified `process_withdrawals` ([Spec](docs/specs/electra/beacon-chain.md#modified-process_withdrawals))
 - [ ] Modified `process_execution_payload` ([Spec](docs/specs/electra/beacon-chain.md#modified-process_execution_payload))
-- [ ] Modified `process_operations` ([Spec](docs/specs/electra/beacon-chain.md#modified-process_operations))
+- [x] Modified `process_operations` ([Spec](docs/specs/electra/beacon-chain.md#modified-process_operations), [PR](https://github.com/lambdaclass/lambda_ethereum_consensus/pull/1424))
 - [ ] Modified `process_attestation` ([Spec](docs/specs/electra/beacon-chain.md#modified-process_attestation))
-- [ ] Modified `process_deposit` ([Spec](docs/specs/electra/beacon-chain.md#modified-process_deposit))
+- [x] Modified `process_deposit` ([Spec](docs/specs/electra/beacon-chain.md#modified-process_deposit), [PR](https://github.com/lambdaclass/lambda_ethereum_consensus/pull/1424))
 - [ ] Modified `process_voluntary_exit` ([Spec](docs/specs/electra/beacon-chain.md#modified-process_voluntary_exit))
 - [ ] New `process_withdrawal_request` ([Spec](docs/specs/electra/beacon-chain.md#new-process_withdrawal_request))
-- [ ] New `process_deposit_request` ([Spec](docs/specs/electra/beacon-chain.md#new-process_deposit_request))
+- [x] New `process_deposit_request` ([Spec](docs/specs/electra/beacon-chain.md#new-process_deposit_request), [PR](https://github.com/lambdaclass/lambda_ethereum_consensus/pull/1424))
 - [ ] New `process_consolidation_request` ([Spec](docs/specs/electra/beacon-chain.md#new-process_consolidation_request))
-
+- [x] New `is_valid_deposit_signature` ([Spec](docs/specs/electra/beacon-chain.md#new-is_valid_deposit_signature), [PR](https://github.com/lambdaclass/lambda_ethereum_consensus/pull/1424))
+- [x] Modified `add_validator_to_registry` ([Spec](docs/specs/electra/beacon-chain.md#modified-add_validator_to_registry), [PR](https://github.com/lambdaclass/lambda_ethereum_consensus/pull/1424))
+- [x] Modified `apply_deposit` ([Spec](docs/specs/electra/beacon-chain.md#modified-apply_deposit), [PR](https://github.com/lambdaclass/lambda_ethereum_consensus/pull/1424))
 ## Execution Engine
 
 - [ ] Modified `is_valid_block_hash` ([Spec](docs/specs/electra/beacon-chain.md#modified-is_valid_block_hash))

lib/lambda_ethereum_consensus/state_transition/epoch_processing.ex

@@ -10,6 +10,7 @@ defmodule LambdaEthereumConsensus.StateTransition.EpochProcessing do
   alias LambdaEthereumConsensus.Utils.BitVector
   alias LambdaEthereumConsensus.Utils.Randao
   alias Types.BeaconState
+  alias Types.DepositMessage
   alias Types.HistoricalSummary
   alias Types.Validator
 
@@ -454,4 +455,154 @@ defmodule LambdaEthereumConsensus.StateTransition.EpochProcessing do
       max(balance + delta, 0)
     end)
   end
+
+  @spec process_pending_deposits(BeaconState.t()) :: {:ok, BeaconState.t()}
+  def process_pending_deposits(%BeaconState{} = state) do
+    available_for_processing =
+      state.deposit_balance_to_consume + Accessors.get_activation_exit_churn_limit(state)
+
+    finalized_slot = Misc.compute_start_slot_at_epoch(state.finalized_checkpoint.epoch)
+
+    {state, churn_limit_reached, processed_amount, deposits_to_postpone, last_processed_index} =
+      state.pending_deposits
+      |> Enum.with_index()
+      |> Enum.reduce_while({state, false, 0, [], 0}, fn {deposit, index},
+                                                        {state, churn_limit_reached,
+                                                         processed_amount, deposits_to_postpone,
+                                                         _last_processed_index} ->
+        cond do
+          # Do not process deposit requests if Eth1 bridge deposits are not yet applied.
+          deposit.slot > Constants.genesis_slot() &&
+              state.eth1_deposit_index < state.deposit_requests_start_index ->
+            {:halt,
+             {state, churn_limit_reached, processed_amount, deposits_to_postpone, index - 1}}
+
+          # Check if deposit has been finalized, otherwise, stop processing.
+          deposit.slot > finalized_slot ->
+            {:halt,
+             {state, churn_limit_reached, processed_amount, deposits_to_postpone, index - 1}}
+
+          # Check if number of processed deposits has not reached the limit, otherwise, stop processing.
+          index >= ChainSpec.get("MAX_PENDING_DEPOSITS_PER_EPOCH") ->
+            {:halt,
+             {state, churn_limit_reached, processed_amount, deposits_to_postpone, index - 1}}
+
+          true ->
+            handle_pending_deposit(
+              deposit,
+              state,
+              churn_limit_reached,
+              processed_amount,
+              deposits_to_postpone,
+              index,
+              available_for_processing
+            )
+        end
+      end)
+
+    deposit_balance_to_consume =
+      if churn_limit_reached do
+        available_for_processing - processed_amount
+      else
+        0
+      end
+
+    {:ok,
+     %BeaconState{
+       state
+       | pending_deposits:
+           Enum.drop(state.pending_deposits, last_processed_index + 1)
+           |> Enum.concat(deposits_to_postpone),
+         deposit_balance_to_consume: deposit_balance_to_consume
+     }}
+  end
+
+  defp handle_pending_deposit(
+         deposit,
+         state,
+         churn_limit_reached,
+         processed_amount,
+         deposits_to_postpone,
+         index,
+         available_for_processing
+       ) do
+    far_future_epoch = Constants.far_future_epoch()
+    next_epoch = Accessors.get_current_epoch(state)
+
+    {is_validator_exited, is_validator_withdrawn} =
+      case Enum.find(state.validators, fn v -> v.pubkey == deposit.pubkey end) do
+        %Validator{} = validator ->
+          {validator.exit_epoch < far_future_epoch, validator.withdrawable_epoch < next_epoch}
+
+        _ ->
+          {false, false}
+      end
+
+    cond do
+      # Deposited balance will never become active. Increase balance but do not consume churn
+      is_validator_withdrawn ->
+        {:ok, state} = apply_pending_deposit(state, deposit)
+
+        {:cont, {state, churn_limit_reached, processed_amount, deposits_to_postpone, index}}
+
+      # Validator is exiting, postpone the deposit until after withdrawable epoch
+      is_validator_exited ->
+        deposits_to_postpone = Enum.concat(deposits_to_postpone, [deposit])
+
+        {:cont, {state, churn_limit_reached, processed_amount, deposits_to_postpone, index}}
+
+      true ->
+        # Check if deposit fits in the churn, otherwise, do no more deposit processing in this epoch.
+        is_churn_limit_reached =
+          processed_amount + deposit.amount > available_for_processing
+
+        if is_churn_limit_reached do
+          {:halt, {state, true, processed_amount, deposits_to_postpone, index - 1}}
+        else
+          # Consume churn and apply deposit.
+          processed_amount = processed_amount + deposit.amount
+          {:ok, state} = apply_pending_deposit(state, deposit)
+          {:cont, {state, false, processed_amount, deposits_to_postpone, index}}
+        end
+    end
+  end
+
+  @spec process_pending_consolidations(BeaconState.t()) :: {:ok, BeaconState.t()}
+  def process_pending_consolidations(%BeaconState{} = state) do
+    # TODO: Not implemented yet
+    {:ok, state}
+  end
+
+  defp apply_pending_deposit(state, deposit) do
+    index =
+      Enum.find_index(state.validators, fn validator -> validator.pubkey == deposit.pubkey end)
+
+    current_validator? = is_number(index)
+
+    valid_signature? =
+      current_validator? ||
+        DepositMessage.valid_deposit_signature?(
+          deposit.pubkey,
+          deposit.withdrawal_credentials,
+          deposit.amount,
+          deposit.signature
+        )
+
+    cond do
+      current_validator? ->
+        {:ok, BeaconState.increase_balance(state, index, deposit.amount)}
+
+      !current_validator? && valid_signature? ->
+        Mutators.add_validator_to_registry(
+          state,
+          deposit.pubkey,
+          deposit.withdrawal_credentials,
+          deposit.amount
+        )
+
+      true ->
+        # Neither a validator nor have a valid signature, we do not apply the deposit
+        {:ok, state}
+    end
+  end
 end

lib/lambda_ethereum_consensus/state_transition/mutators.ex

@@ -5,6 +5,8 @@ defmodule LambdaEthereumConsensus.StateTransition.Mutators do
   alias LambdaEthereumConsensus.StateTransition.Accessors
   alias LambdaEthereumConsensus.StateTransition.Misc
   alias Types.BeaconState
+  alias Types.DepositMessage
+  alias Types.PendingDeposit
   alias Types.Validator
 
   @doc """
@@ -122,31 +124,49 @@ defmodule LambdaEthereumConsensus.StateTransition.Mutators do
           Types.uint64(),
           Types.bls_signature()
         ) :: {:ok, BeaconState.t()} | {:error, String.t()}
-  def apply_deposit(state, pubkey, withdrawal_credentials, amount, signature) do
-    case Enum.find_index(state.validators, fn validator -> validator.pubkey == pubkey end) do
-      index when is_number(index) ->
-        {:ok, BeaconState.increase_balance(state, index, amount)}
-
-      _ ->
-        deposit_message = %Types.DepositMessage{
-          pubkey: pubkey,
-          withdrawal_credentials: withdrawal_credentials,
-          amount: amount
-        }
-
-        domain = Misc.compute_domain(Constants.domain_deposit())
+  def apply_deposit(state, pubkey, withdrawal_credentials, amount, sig) do
+    current_validator? = Enum.any?(state.validators, &(&1.pubkey == pubkey))
 
-        signing_root = Misc.compute_signing_root(deposit_message, domain)
+    valid_signature? =
+      current_validator? ||
+        DepositMessage.valid_deposit_signature?(pubkey, withdrawal_credentials, amount, sig)
 
-        if Bls.valid?(pubkey, signing_root, signature) do
-          apply_initial_deposit(state, pubkey, withdrawal_credentials, amount)
+    if !current_validator? && !valid_signature? do
+      # Neither a validator nor have a valid signature, we do not apply the deposit
+      {:ok, state}
+    else
+      updated_state =
+        if current_validator? do
+          state
         else
-          {:ok, state}
+          {:ok, state} = add_validator_to_registry(state, pubkey, withdrawal_credentials, 0)
+          state
         end
+
+      deposit = %PendingDeposit{
+        pubkey: pubkey,
+        withdrawal_credentials: withdrawal_credentials,
+        amount: amount,
+        signature: sig,
+        slot: Constants.genesis_slot()
+      }
+
+      {:ok,
+       %BeaconState{
+         updated_state
+         | pending_deposits: updated_state.pending_deposits ++ [deposit]
+       }}
     end
   end
 
-  defp apply_initial_deposit(%BeaconState{} = state, pubkey, withdrawal_credentials, amount) do
+  @spec add_validator_to_registry(
+          BeaconState.t(),
+          Types.bls_pubkey(),
+          Types.bytes32(),
+          Types.gwei()
+        ) ::
+          {:ok, BeaconState.t()}
+  def add_validator_to_registry(%BeaconState{} = state, pubkey, withdrawal_credentials, amount) do
     Types.Deposit.get_validator_from_deposit(pubkey, withdrawal_credentials, amount)
     |> then(&Aja.Vector.append(state.validators, &1))
     |> then(

lib/lambda_ethereum_consensus/state_transition/operations.ex

@@ -13,17 +13,21 @@ defmodule LambdaEthereumConsensus.StateTransition.Operations do
   alias LambdaEthereumConsensus.Utils.BitList
   alias LambdaEthereumConsensus.Utils.BitVector
   alias LambdaEthereumConsensus.Utils.Randao
+  alias Types.PendingDeposit
 
   alias Types.Attestation
   alias Types.BeaconBlock
   alias Types.BeaconBlockBody
   alias Types.BeaconBlockHeader
   alias Types.BeaconState
+  alias Types.ConsolidationRequest
+  alias Types.DepositRequest
   alias Types.ExecutionPayload
   alias Types.ExecutionPayloadHeader
   alias Types.SyncAggregate
   alias Types.Validator
   alias Types.Withdrawal
+  alias Types.WithdrawalRequest
 
   @spec process_block_header(BeaconState.t(), BeaconBlock.t()) ::
           {:ok, BeaconState.t()} | {:error, String.t()}
@@ -918,6 +922,43 @@ defmodule LambdaEthereumConsensus.StateTransition.Operations do
     end
   end
 
+  @spec process_deposit_request(BeaconState.t(), DepositRequest.t()) :: {:ok, BeaconState.t()}
+  def process_deposit_request(state, deposit_request) do
+    start_index =
+      if state.deposit_requests_start_index == Constants.unset_deposit_requests_start_index(),
+        do: deposit_request.index,
+        else: state.deposit_requests_start_index
+
+    deposit = %PendingDeposit{
+      pubkey: deposit_request.pubkey,
+      withdrawal_credentials: deposit_request.withdrawal_credentials,
+      amount: deposit_request.amount,
+      signature: deposit_request.signature,
+      slot: state.slot
+    }
+
+    {:ok,
+     %BeaconState{
+       state
+       | deposit_requests_start_index: start_index,
+         pending_deposits: state.pending_deposits ++ [deposit]
+     }}
+  end
+
+  @spec process_withdrawal_request(BeaconState.t(), WithdrawalRequest.t()) ::
+          {:ok, BeaconState.t()}
+  def process_withdrawal_request(state, _withdrawal_request) do
+    # TODO: Not implemented yet
+    {:ok, state}
+  end
+
+  @spec process_consolidation_request(BeaconState.t(), ConsolidationRequest.t()) ::
+          {:ok, BeaconState.t()}
+  def process_consolidation_request(state, _consolidation_request) do
+    # TODO: Not implemented yet
+    {:ok, state}
+  end
+
   @spec process_operations(BeaconState.t(), BeaconBlockBody.t()) ::
           {:ok, BeaconState.t()} | {:error, String.t()}
   def process_operations(state, body) do
@@ -934,6 +975,17 @@ defmodule LambdaEthereumConsensus.StateTransition.Operations do
         body.bls_to_execution_changes,
         &process_bls_to_execution_change/2
       )
+      |> for_ops(:deposit_request, body.execution_requests.deposits, &process_deposit_request/2)
+      |> for_ops(
+        :withdrawal_request,
+        body.execution_requests.withdrawals,
+        &process_withdrawal_request/2
+      )
+      |> for_ops(
+        :consolidation_request,
+        body.execution_requests.consolidations,
+        &process_consolidation_request/2
+      )
     end
   end
 
@@ -954,13 +1006,22 @@ defmodule LambdaEthereumConsensus.StateTransition.Operations do
 
   @spec verify_deposits(BeaconState.t(), BeaconBlockBody.t()) :: :ok | {:error, String.t()}
   defp verify_deposits(state, body) do
-    deposit_count = state.eth1_data.deposit_count - state.eth1_deposit_index
-    deposit_limit = min(ChainSpec.get("MAX_DEPOSITS"), deposit_count)
+    eth1_deposit_index_limit =
+      min(state.eth1_data.deposit_count, state.deposit_requests_start_index)
 
-    if length(body.deposits) == deposit_limit do
-      :ok
-    else
-      {:error, "deposits length mismatch"}
+    max_deposits = ChainSpec.get("MAX_DEPOSITS")
+
+    cond do
+      state.eth1_deposit_index < eth1_deposit_index_limit and
+          length(body.deposits) ==
+            min(max_deposits, eth1_deposit_index_limit - state.eth1_deposit_index) ->
+        :ok
+
+      state.eth1_deposit_index >= eth1_deposit_index_limit and Enum.empty?(body.deposits) ->
+        :ok
+
+      true ->
+        {:error, "Invalid deposits"}
     end
   end
 end

lib/lambda_ethereum_consensus/state_transition/state_transition.ex

@@ -156,6 +156,8 @@ defmodule LambdaEthereumConsensus.StateTransition do
     |> epoch_op(:registry_updates, &EpochProcessing.process_registry_updates/1)
     |> epoch_op(:slashings, &EpochProcessing.process_slashings/1)
     |> epoch_op(:eth1_data_reset, &EpochProcessing.process_eth1_data_reset/1)
+    |> epoch_op(:pending_deposits, &EpochProcessing.process_pending_deposits/1)
+    |> epoch_op(:pending_consolidations, &EpochProcessing.process_pending_consolidations/1)
     |> epoch_op(:effective_balance_updates, &EpochProcessing.process_effective_balance_updates/1)
     |> epoch_op(:slashings_reset, &EpochProcessing.process_slashings_reset/1)
     |> epoch_op(:randao_mixes_reset, &EpochProcessing.process_randao_mixes_reset/1)