73 lines
3.1 KiB
Markdown
73 lines
3.1 KiB
Markdown
# Ethereum 2.0 The Merge
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**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.
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**Notice**: This document is a work-in-progress for researchers and implementers.
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## Table of contents
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<!-- TOC -->
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<!-- START doctoc generated TOC please keep comment here to allow auto update -->
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<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
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- [Introduction](#introduction)
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- [Prerequisites](#prerequisites)
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- [Beacon chain responsibilities](#beacon-chain-responsibilities)
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- [Block proposal](#block-proposal)
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- [Constructing the `BeaconBlockBody`](#constructing-the-beaconblockbody)
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- [Execution Payload](#execution-payload)
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- [`get_pow_chain_head`](#get_pow_chain_head)
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- [`produce_execution_payload`](#produce_execution_payload)
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<!-- END doctoc generated TOC please keep comment here to allow auto update -->
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<!-- /TOC -->
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## Introduction
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This document represents the changes to be made in the code of an "honest validator" to implement executable beacon chain proposal.
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## Prerequisites
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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.
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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.
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## Beacon chain responsibilities
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All validator responsibilities remain unchanged other than those noted below. Namely, the transition block handling and the addition of `ExecutionPayload`.
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### Block proposal
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#### Constructing the `BeaconBlockBody`
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##### Execution Payload
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###### `get_pow_chain_head`
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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.
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###### `produce_execution_payload`
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Let `produce_execution_payload(parent_hash: Hash32, timestamp: uint64) -> ExecutionPayload` be the function that produces new instance of execution payload.
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The body of this function is implementation dependent.
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* Set `block.body.execution_payload = get_execution_payload(state)` where:
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```python
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def get_execution_payload(state: BeaconState) -> ExecutionPayload:
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if not is_transition_completed(state):
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pow_block = get_pow_chain_head()
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if not is_valid_transition_block(pow_block):
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# Pre-merge, empty payload
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return ExecutionPayload()
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else:
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# Signify merge via producing on top of the last PoW block
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timestamp = compute_time_at_slot(state, state.slot)
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return produce_execution_payload(pow_block.block_hash, timestamp)
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# Post-merge, normal payload
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execution_parent_hash = state.latest_execution_payload_header.block_hash
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timestamp = compute_time_at_slot(state, state.slot)
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return produce_execution_payload(execution_parent_hash, timestamp)
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```
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