104 lines
4.2 KiB
Markdown
104 lines
4.2 KiB
Markdown
# Ethereum 2.0 The Merge
|
|
|
|
**Warning:** This document is currently based on [Phase 0](../phase0/validator.md) but will be rebased to [Altair](../altair/validator.md) once the latter is shipped.
|
|
|
|
**Notice**: This document is a work-in-progress for researchers and implementers.
|
|
|
|
## 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)
|
|
- [Protocols](#protocols)
|
|
- [`ExecutionEngine`](#executionengine)
|
|
- [`assemble_block`](#assemble_block)
|
|
- [Beacon chain responsibilities](#beacon-chain-responsibilities)
|
|
- [Block proposal](#block-proposal)
|
|
- [Constructing the `BeaconBlockBody`](#constructing-the-beaconblockbody)
|
|
- [Execution Payload](#execution-payload)
|
|
- [`get_pow_chain_head`](#get_pow_chain_head)
|
|
|
|
<!-- 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" to implement executable beacon chain proposal.
|
|
|
|
## Prerequisites
|
|
|
|
This document is an extension of the [Phase 0 -- Validator](../phase0/validator.md). All behaviors and definitions defined in the Phase 0 doc carry over unless explicitly noted or overridden.
|
|
|
|
All terminology, constants, functions, and protocol mechanics defined in the updated Beacon Chain doc of [The Merge](./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.
|
|
|
|
## Protocols
|
|
|
|
### `ExecutionEngine`
|
|
|
|
The following methods are added to the `ExecutionEngine` protocol for use as a validator:
|
|
|
|
#### `assemble_block`
|
|
|
|
Produces a new instance of an execution payload, with the specified `timestamp`,
|
|
on top of the execution payload chain tip identified by `block_hash`.
|
|
|
|
The body of this function is implementation dependent.
|
|
The Consensus API may be used to implement this with an external execution engine.
|
|
|
|
```python
|
|
def assemble_block(self: ExecutionEngine, block_hash: Hash32, timestamp: uint64, random: Bytes32) -> ExecutionPayload:
|
|
...
|
|
```
|
|
|
|
## Beacon chain responsibilities
|
|
|
|
All validator responsibilities remain unchanged other than those noted below. Namely, the transition block handling and the addition of `ExecutionPayload`.
|
|
|
|
### Block proposal
|
|
|
|
#### Constructing the `BeaconBlockBody`
|
|
|
|
##### Execution Payload
|
|
|
|
###### `get_pow_chain_head`
|
|
|
|
Let `get_pow_chain_head() -> PowBlock` be the function that returns the head of the PoW chain. The body of the function is implementation specific.
|
|
|
|
* Set `block.body.execution_payload = get_execution_payload(state, transition_store, execution_engine)` where:
|
|
|
|
```python
|
|
def compute_randao_mix(state: BeaconState, randao_reveal: BLSSignature) -> Bytes32:
|
|
epoch = get_current_epoch(state)
|
|
return xor(get_randao_mix(state, epoch), hash(randao_reveal))
|
|
|
|
|
|
def produce_execution_payload(state: BeaconState,
|
|
parent_hash: Hash32,
|
|
randao_reveal: BLSSignature,
|
|
execution_engine: ExecutionEngine) -> ExecutionPayload:
|
|
timestamp = compute_timestamp_at_slot(state, state.slot)
|
|
randao_mix = compute_randao_mix(state, randao_reveal)
|
|
return execution_engine.assemble_block(parent_hash, timestamp, randao_mix)
|
|
|
|
|
|
def get_execution_payload(state: BeaconState,
|
|
transition_store: TransitionStore,
|
|
randao_reveal: BLSSignature,
|
|
execution_engine: ExecutionEngine) -> ExecutionPayload:
|
|
if not is_merge_complete(state):
|
|
pow_block = get_pow_chain_head()
|
|
if not is_valid_terminal_pow_block(transition_store, pow_block):
|
|
# Pre-merge, empty payload
|
|
return ExecutionPayload()
|
|
else:
|
|
# Signify merge via producing on top of the last PoW block
|
|
return produce_execution_payload(state, pow_block.block_hash, randao_reveal, execution_engine)
|
|
|
|
# Post-merge, normal payload
|
|
parent_hash = state.latest_execution_payload_header.block_hash
|
|
return produce_execution_payload(state, parent_hash, randao_reveal, execution_engine)
|
|
```
|