Various spec fixes for EIP-7251

specs/_features/eip7251/beacon-chain.md

@@ -30,6 +30,8 @@
   - [Extended Containers](#extended-containers)
     - [`BeaconState`](#beaconstate)
     - [`BeaconBlockBody`](#beaconblockbody)
+    - [`ExecutionPayload`](#executionpayload)
+    - [`ExecutionPayloadHeader`](#executionpayloadheader)
 - [Helpers](#helpers)
   - [Predicates](#predicates)
     - [Updated `is_eligible_for_activation_queue`](#updated-is_eligible_for_activation_queue)
@@ -75,13 +77,14 @@
         - [New `process_consolidation`](#new-process_consolidation)
       - [Voluntary exits](#voluntary-exits)
         - [Updated `process_voluntary_exit`](#updated-process_voluntary_exit)
+- [Testing](#testing)
 
 <!-- END doctoc generated TOC please keep comment here to allow auto update -->
 <!-- /TOC -->
 
 ## Introduction
 
-See [a modest proposal](https://notes.ethereum.org/@mikeneuder/increase-maxeb), the [diff view](https://github.com/michaelneuder/consensus-specs/pull/3/files) and 
+See [a modest proposal](https://notes.ethereum.org/@mikeneuder/increase-maxeb), the [diff view](https://github.com/michaelneuder/consensus-specs/pull/3/files) and
 [security considerations](https://notes.ethereum.org/@fradamt/meb-increase-security).
 
 *Note:* This specification is built upon [Deneb](../../deneb/beacon-chain.md).
@@ -136,6 +139,7 @@ The following values are (non-configurable) constants used throughout the specif
 
 | Name | Value | Description |
 | - | - | - |
+| `MAX_WITHDRAWAL_REQUESTS_PER_PAYLOAD` | `uint64(16)` |
 | `MAX_PARTIAL_WITHDRAWALS_PER_PAYLOAD` | `uint64(2**3)` (= 8) | Maximum amount of partial withdrawals allowed in each payload |
 
 ### State list lengths
@@ -282,12 +286,64 @@ class BeaconBlockBody(Container):
     voluntary_exits: List[SignedVoluntaryExit, MAX_VOLUNTARY_EXITS]
     sync_aggregate: SyncAggregate
     # Execution
-    execution_payload: ExecutionPayload 
+    execution_payload: ExecutionPayload
     bls_to_execution_changes: List[SignedBLSToExecutionChange, MAX_BLS_TO_EXECUTION_CHANGES]
     blob_kzg_commitments: List[KZGCommitment, MAX_BLOB_COMMITMENTS_PER_BLOCK]
     consolidations: List[SignedConsolidation, MAX_CONSOLIDATIONS]  # [New in EIP-7251]
 ```
 
+#### `ExecutionPayload`
+
+```python
+class ExecutionPayload(Container):
+    # Execution block header fields
+    parent_hash: Hash32
+    fee_recipient: ExecutionAddress  # 'beneficiary' in the yellow paper
+    state_root: Bytes32
+    receipts_root: Bytes32
+    logs_bloom: ByteVector[BYTES_PER_LOGS_BLOOM]
+    prev_randao: Bytes32  # 'difficulty' in the yellow paper
+    block_number: uint64  # 'number' in the yellow paper
+    gas_limit: uint64
+    gas_used: uint64
+    timestamp: uint64
+    extra_data: ByteList[MAX_EXTRA_DATA_BYTES]
+    base_fee_per_gas: uint256
+    # Extra payload fields
+    block_hash: Hash32  # Hash of execution block
+    transactions: List[Transaction, MAX_TRANSACTIONS_PER_PAYLOAD]
+    withdrawals: List[Withdrawal, MAX_WITHDRAWALS_PER_PAYLOAD]
+    blob_gas_used: uint64
+    excess_blob_gas: uint64
+    withdraw_requests: List[ExecutionLayerWithdrawRequest, MAX_WITHDRAWAL_REQUESTS_PER_PAYLOAD]  # [New in EIP-7251]
+```
+
+#### `ExecutionPayloadHeader`
+
+```python
+class ExecutionPayloadHeader(Container):
+    # Execution block header fields
+    parent_hash: Hash32
+    fee_recipient: ExecutionAddress
+    state_root: Bytes32
+    receipts_root: Bytes32
+    logs_bloom: ByteVector[BYTES_PER_LOGS_BLOOM]
+    prev_randao: Bytes32
+    block_number: uint64
+    gas_limit: uint64
+    gas_used: uint64
+    timestamp: uint64
+    extra_data: ByteList[MAX_EXTRA_DATA_BYTES]
+    base_fee_per_gas: uint256
+    # Extra payload fields
+    block_hash: Hash32  # Hash of execution block
+    transactions_root: Root
+    withdrawals_root: Root
+    blob_gas_used: uint64
+    excess_blob_gas: uint64
+    withdraw_requests_root: Root  # [New in EIP-7251]
+```
+
 ## Helpers
 
 ### Predicates
@@ -386,7 +442,7 @@ def get_churn_limit(state: BeaconState) -> Gwei:
     Return the churn limit for the current epoch.
     """
     churn = max(
-        MIN_PER_EPOCH_CHURN_LIMIT_EIP7251, 
+        MIN_PER_EPOCH_CHURN_LIMIT_EIP7251,
         get_total_active_balance(state) // CHURN_LIMIT_QUOTIENT
     )
     return churn - churn % EFFECTIVE_BALANCE_INCREMENT
@@ -472,7 +528,6 @@ def queue_excess_active_balance(state: BeaconState, index: ValidatorIndex) -> No
 
 #### New `compute_exit_epoch_and_update_churn`
 
-
 ```python
 def compute_exit_epoch_and_update_churn(state: BeaconState, exit_balance: Gwei) -> Epoch:
     earliest_exit_epoch = compute_activation_exit_epoch(get_current_epoch(state))
@@ -566,16 +621,23 @@ def process_epoch(state: BeaconState) -> None:
     process_effective_balance_updates(state)  # [Modified in EIP7251]
     process_slashings_reset(state)
     process_randao_mixes_reset(state)
+    process_historical_summaries_update(state)
+    process_participation_flag_updates(state)
+    process_sync_committee_updates(state)
 ```
 
 #### Updated  `process_registry_updates`
 
+`process_registry_updates` uses the updated definition of `initiate_validator_exit`
+and changes how the activation epochs are computed for eligible validators.
+
 ```python
 def process_registry_updates(state: BeaconState) -> None:
     # Process activation eligibility and ejections
     for index, validator in enumerate(state.validators):
         if is_eligible_for_activation_queue(validator):
             validator.activation_eligibility_epoch = get_current_epoch(state) + 1
+
         if (
             is_active_validator(validator, get_current_epoch(state))
             and validator.effective_balance <= EJECTION_BALANCE
@@ -607,7 +669,7 @@ def process_pending_balance_deposits(state: BeaconState) -> None:
     state.pending_balance_deposits = state.pending_balance_deposits[next_deposit_index:]
 
     if len(state.pending_balance_deposits) == 0:
-        state.deposit_balance_to_consume = 0
+        state.deposit_balance_to_consume = Gwei(0)
     else:
         state.deposit_balance_to_consume = available_for_processing - processed_amount
 ```
@@ -638,6 +700,8 @@ def process_pending_consolidations(state: BeaconState) -> None:
 
 #### Updated `process_effective_balance_updates`
 
+`process_effective_balance_updates` is updated with a new limit for the maximum effective balance.
+
 ```python
 def process_effective_balance_updates(state: BeaconState) -> None:
     # Update effective balances with hysteresis
@@ -760,7 +824,7 @@ def process_withdrawals(state: BeaconState, payload: ExecutionPayload) -> None:
         state.next_withdrawal_validator_index = next_validator_index
 ```
 
-#### Operations 
+#### Operations
 
 ##### Updated `process_operations`
 
@@ -779,14 +843,16 @@ def process_operations(state: BeaconState, body: BeaconBlockBody) -> None:
     for_ops(body.deposits, process_deposit)  # [Modified in EIP7251]
     for_ops(body.voluntary_exits, process_voluntary_exit)  # [Modified in EIP7251]
     for_ops(body.bls_to_execution_changes, process_bls_to_execution_change)
-    for_ops(body.execution_payload.withdraw_requests, process_execution_layer_withdraw_request)  # New in EIP7251
-    for_ops(body.consolidations, process_consolidation)  # New in EIP7251
+    for_ops(body.execution_payload.withdraw_requests, process_execution_layer_withdraw_request)  # [New in EIP7251]
+    for_ops(body.consolidations, process_consolidation)  # [New in EIP7251]
 ```
 
 ##### Deposits
 
 ###### Updated  `apply_deposit`
 
+*NOTE*: `process_deposit` is updated with a new definition of `apply_deposit`.
+
 ```python
 def apply_deposit(state: BeaconState,
                   pubkey: BLSPubkey,
@@ -819,7 +885,7 @@ def apply_deposit(state: BeaconState,
 def is_valid_deposit_signature(pubkey: BLSPubkey,
                                withdrawal_credentials: Bytes32,
                                amount: uint64,
-                               signature: BLSSignature) -> None:
+                               signature: BLSSignature) -> bool:
     deposit_message = DepositMessage(
         pubkey=pubkey,
         withdrawal_credentials=withdrawal_credentials,
@@ -862,7 +928,7 @@ def get_validator_from_deposit(pubkey: BLSPubkey, withdrawal_credentials: Bytes3
     )
 ```
 
-##### Withdrawals 
+##### Withdrawals
 
 ###### New `process_execution_layer_withdraw_request`
 
@@ -874,7 +940,7 @@ def process_execution_layer_withdraw_request(
     amount = execution_layer_withdraw_request.amount
     is_full_exit_request = amount == FULL_EXIT_REQUEST_AMOUNT
 
-    # If partial withdrawal queue is full, only full exits are processed 
+    # If partial withdrawal queue is full, only full exits are processed
     if len(state.pending_partial_withdrawals) >= PENDING_PARTIAL_WITHDRAWALS_LIMIT and not is_full_exit_request:
         return
 
@@ -947,7 +1013,7 @@ def process_consolidation(state: BeaconState, signed_consolidation: SignedConsol
     assert source_validator.exit_epoch == FAR_FUTURE_EPOCH
     assert target_validator.exit_epoch == FAR_FUTURE_EPOCH
     # Consolidations must specify an epoch when they become valid; they are not valid before then
-    assert current_epoch >= consolidation.epoch 
+    assert current_epoch >= consolidation.epoch
 
     # Verify the source and the target have Execution layer withdrawal credentials
     assert has_execution_withdrawal_credential(source_validator)
@@ -989,12 +1055,70 @@ def process_voluntary_exit(state: BeaconState, signed_voluntary_exit: SignedVolu
     assert get_current_epoch(state) >= voluntary_exit.epoch
     # Verify the validator has been active long enough
     assert get_current_epoch(state) >= validator.activation_epoch + SHARD_COMMITTEE_PERIOD
+    # Only exit validator if it has no pending withdrawals in the queue
+    assert get_pending_balance_to_withdraw(state, voluntary_exit.validator_index) == 0  # [New in EIP7251]
     # Verify signature
-    domain = get_domain(state, DOMAIN_VOLUNTARY_EXIT, voluntary_exit.epoch)
+    domain = compute_domain(DOMAIN_VOLUNTARY_EXIT, CAPELLA_FORK_VERSION, state.genesis_validators_root)
     signing_root = compute_signing_root(voluntary_exit, domain)
     assert bls.Verify(validator.pubkey, signing_root, signed_voluntary_exit.signature)
-    # Only exit validator if it has no pending withdrawals in the queue
-    assert get_pending_balance_to_withdraw(state, voluntary_exit.validator_index) == 0  # [New in EIP7251]
     # Initiate exit
     initiate_validator_exit(state, voluntary_exit.validator_index)
 ```
+
+## Testing
+
+*Note*: The function `initialize_beacon_state_from_eth1` is modified for pure EIP-7251 testing only.
+
+```python
+def initialize_beacon_state_from_eth1(eth1_block_hash: Hash32,
+                                      eth1_timestamp: uint64,
+                                      deposits: Sequence[Deposit],
+                                      execution_payload_header: ExecutionPayloadHeader=ExecutionPayloadHeader()
+                                      ) -> BeaconState:
+    fork = Fork(
+        previous_version=EIP7251_FORK_VERSION,  # [Modified in EIP-7251] for testing only
+        current_version=EIP7251_FORK_VERSION,  # [Modified in EIP-7251]
+        epoch=GENESIS_EPOCH,
+    )
+    state = BeaconState(
+        genesis_time=eth1_timestamp + GENESIS_DELAY,
+        fork=fork,
+        eth1_data=Eth1Data(block_hash=eth1_block_hash, deposit_count=uint64(len(deposits))),
+        latest_block_header=BeaconBlockHeader(body_root=hash_tree_root(BeaconBlockBody())),
+        randao_mixes=[eth1_block_hash] * EPOCHS_PER_HISTORICAL_VECTOR,  # Seed RANDAO with Eth1 entropy
+    )
+
+    # Process deposits
+    leaves = list(map(lambda deposit: deposit.data, deposits))
+    for index, deposit in enumerate(deposits):
+        deposit_data_list = List[DepositData, 2**DEPOSIT_CONTRACT_TREE_DEPTH](*leaves[:index + 1])
+        state.eth1_data.deposit_root = hash_tree_root(deposit_data_list)
+        process_deposit(state, deposit)
+
+    # Process deposit balance updates
+    for deposit in state.pending_balance_deposits:
+        increase_balance(state, deposit.index, deposit.amount)
+    state.pending_balance_deposits = []
+
+    # Process activations
+    for index, validator in enumerate(state.validators):
+        balance = state.balances[index]
+        validator.effective_balance = min(balance - balance % EFFECTIVE_BALANCE_INCREMENT, MAX_EFFECTIVE_BALANCE)
+        if validator.effective_balance == MAX_EFFECTIVE_BALANCE:
+            validator.activation_eligibility_epoch = GENESIS_EPOCH
+            validator.activation_epoch = GENESIS_EPOCH
+
+    # Set genesis validators root for domain separation and chain versioning
+    state.genesis_validators_root = hash_tree_root(state.validators)
+
+    # Fill in sync committees
+    # Note: A duplicate committee is assigned for the current and next committee at genesis
+    state.current_sync_committee = get_next_sync_committee(state)
+    state.next_sync_committee = get_next_sync_committee(state)
+
+    # Initialize the execution payload header
+    # If empty, will initialize a chain that has not yet gone through the Merge transition
+    state.latest_execution_payload_header = execution_payload_header
+
+    return state
+```

specs/_features/eip7251/fork.md

@@ -131,8 +131,7 @@ def upgrade_to_eip7251(pre: deneb.BeaconState) -> BeaconState:
     # Ensure early adopters of compounding credentials go through the activation churn
     for index, validator in enumerate(post.validators):
         if has_compounding_withdrawal_credential(validator):
-            queue_excess_active_balance(post, index)
+            queue_excess_active_balance(post, ValidatorIndex(index))
 
     return post
 ```
-

specs/_features/eip7251/validator.md

@@ -0,0 +1,73 @@
+# EIP-7251 -- Honest Validator
+
+## Table of contents
+
+<!-- TOC -->
+<!-- START doctoc generated TOC please keep comment here to allow auto update -->
+<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
+
+- [Introduction](#introduction)
+- [Prerequisites](#prerequisites)
+- [Beacon chain responsibilities](#beacon-chain-responsibilities)
+  - [Block and sidecar proposal](#block-and-sidecar-proposal)
+    - [Constructing the `BeaconBlockBody`](#constructing-the-beaconblockbody)
+      - [ExecutionPayload](#executionpayload)
+
+<!-- END doctoc generated TOC please keep comment here to allow auto update -->
+<!-- /TOC -->
+
+## Introduction
+
+This document represents the changes to be made in the code of an "honest validator".
+
+## Prerequisites
+
+This document is an extension of the [Deneb -- Honest Validator](../deneb/validator.md) guide.
+All behaviors and definitions defined in this document, and documents it extends, carry over unless explicitly noted or overridden.
+
+All terminology, constants, functions, and protocol mechanics defined in the updated [Beacon Chain doc of EIP-7251](./beacon-chain.md) are requisite for this document and used throughout.
+Please see related Beacon Chain doc before continuing and use them as a reference throughout.
+
+## Beacon chain responsibilities
+
+All validator responsibilities remain unchanged other than those noted below.
+
+### Block and sidecar proposal
+
+#### Constructing the `BeaconBlockBody`
+
+##### ExecutionPayload
+
+`prepare_execution_payload` is updated from the Deneb specs.
+
+*Note*: In this section, `state` is the state of the slot for the block proposal _without_ the block yet applied.
+That is, `state` is the `previous_state` processed through any empty slots up to the assigned slot using `process_slots(previous_state, slot)`.
+
+*Note*: The only change to `prepare_execution_payload` is the new definition of `get_expected_withdrawals`.
+
+```python
+def prepare_execution_payload(state: BeaconState,
+                              safe_block_hash: Hash32,
+                              finalized_block_hash: Hash32,
+                              suggested_fee_recipient: ExecutionAddress,
+                              execution_engine: ExecutionEngine) -> Optional[PayloadId]:
+    # Verify consistency of the parent hash with respect to the previous execution payload header
+    parent_hash = state.latest_execution_payload_header.block_hash
+
+    # Set the forkchoice head and initiate the payload build process
+    withdrawals, _ = get_expected_withdrawals(state)  # [Modified in EIP-7251]
+
+    payload_attributes = PayloadAttributes(
+        timestamp=compute_timestamp_at_slot(state, state.slot),
+        prev_randao=get_randao_mix(state, get_current_epoch(state)),
+        suggested_fee_recipient=suggested_fee_recipient,
+        withdrawals=withdrawals,
+        parent_beacon_block_root=hash_tree_root(state.latest_block_header),
+    )
+    return execution_engine.notify_forkchoice_updated(
+        head_block_hash=parent_hash,
+        safe_block_hash=safe_block_hash,
+        finalized_block_hash=finalized_block_hash,
+        payload_attributes=payload_attributes,
+    )
+```