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1a8b7469e3
* move quarantine outside of chaindag
The quarantine has been part of the ChainDAG for the longest time, but
this design has a few issues:
* the function in which blocks are verified and added to the dag becomes
reentrant and therefore difficult to reason about - we're currently
using a stateful flag to work around it
* quarantined blocks bypass the processing queue leading to a processing
stampede
* the quarantine flow is unsuitable for orphaned attestations - these
should also should be quarantined eventually
Instead of processing the quarantine inside ChainDAG, this PR moves
re-queueing to `block_processor` which already is responsible for
dealing with follow-up work when a block is added to the dag
This sets the stage for keeping attestations in the quarantine as well.
Also:
* make `BlockError` `{.pure.}`
* avoid use of `ValidationResult` in block clearance (that's for gossip)
Consensus object pools
This folder holds the various consensus object pools needed for a blockchain client.
Object in those pools have passed the "gossip validation" filter according to specs:
- blocks: https://github.com/ethereum/consensus-specs/blob/v1.1.6/specs/phase0/p2p-interface.md#beacon_block
- aggregate attestations: https://github.com/ethereum/consensus-specs/blob/v1.1.6/specs/phase0/p2p-interface.md#beacon_aggregate_and_proof
- unaggregated attestation: https://github.com/ethereum/consensus-specs/blob/v1.1.6/specs/phase0/p2p-interface.md#beacon_attestation_subnet_id
- voluntary exits: https://github.com/ethereum/consensus-specs/blob/v1.1.6/specs/phase0/p2p-interface.md#voluntary_exit
- Attester slashings: https://github.com/ethereum/consensus-specs/blob/v1.1.6/specs/phase0/p2p-interface.md#attester_slashing
- Proposer slashings: https://github.com/ethereum/consensus-specs/blob/v1.1.6/specs/phase0/p2p-interface.md#proposer_slashing
After "gossip validation" the consensus objects can be rebroadcasted as they are optimistically good, however for internal processing further verification is needed. For blocks, this means verifying state transition and all contained cryptographic signatures (instead of just the proposer signature). For other consensus objects, it is possible that gossip validation is a superset of consensus verification (TODO).
The pools presenet in this folder are:
- block_pools:
- block_quarantine: for seemingly valid blocks that are on a fork unknown to us.
- block_clearance: to verify (state_transition + cryptography) candidate blocks.
- blockchain_dag: an in-memory direct-acyclic graph of fully validated and verified blockchain candidates with the tail being the last finalized epoch. A block in the DAG MUST be in the fork choice and a block in the fork choice MUST be in the DAG (except for orphans following finalization). On finalization non-empty epoch blocks are stored in the beacon_chain_db.
- attestation_pool: Handles the attestation received from gossip and collect them for fork choice.
- exit_pool: Handle voluntary exits and forced exits (attester slashings and proposer slashings)