nimbus-eth2/beacon_chain/consensus_object_pools
Jacek Sieka a7a65bce42
disentangle eth2 types from the ssz library (#2785)
* reorganize ssz dependencies

This PR continues the work in
https://github.com/status-im/nimbus-eth2/pull/2646,
https://github.com/status-im/nimbus-eth2/pull/2779 as well as past
issues with serialization and type, to disentangle SSZ from eth2 and at
the same time simplify imports and exports with a structured approach.

The principal idea here is that when a library wants to introduce SSZ
support, they do so via 3 files:

* `ssz_codecs` which imports and reexports `codecs` - this covers the
basic byte conversions and ensures no overloads get lost
* `xxx_merkleization` imports and exports `merkleization` to specialize
and get access to `hash_tree_root` and friends
* `xxx_ssz_serialization` imports and exports `ssz_serialization` to
specialize ssz for a specific library

Those that need to interact with SSZ always import the `xxx_` versions
of the modules and never `ssz` itself so as to keep imports simple and
safe.

This is similar to how the REST / JSON-RPC serializers are structured in
that someone wanting to serialize spec types to REST-JSON will import
`eth2_rest_serialization` and nothing else.

* split up ssz into a core library that is independendent of eth2 types
* rename `bytes_reader` to `codec` to highlight that it contains coding
and decoding of bytes and native ssz types
* remove tricky List init overload that causes compile issues
* get rid of top-level ssz import
* reenable merkleization tests
* move some "standard" json serializers to spec
* remove `ValidatorIndex` serialization for now
* remove test_ssz_merkleization
* add tests for over/underlong byte sequences
* fix broken seq[byte] test - seq[byte] is not an SSZ type

There are a few things this PR doesn't solve:

* like #2646 this PR is weak on how to handle root and other
dontSerialize fields that "sometimes" should be computed - the same
problem appears in REST / JSON-RPC etc

* Fix a build problem on macOS

* Another way to fix the macOS builds

Co-authored-by: Zahary Karadjov <zahary@gmail.com>
2021-08-18 20:57:58 +02:00
..
README.md Consensus object pools [reorg 4/5] (#2374) 2021-03-04 10:13:44 +01:00
attestation_pool.nim disentangle eth2 types from the ssz library (#2785) 2021-08-18 20:57:58 +02:00
block_clearance.nim disentangle eth2 types from the ssz library (#2785) 2021-08-18 20:57:58 +02:00
block_pools_types.nim rework spec imports (#2779) 2021-08-12 13:08:20 +00:00
block_quarantine.nim rework spec imports (#2779) 2021-08-12 13:08:20 +00:00
blockchain_dag.nim disentangle eth2 types from the ssz library (#2785) 2021-08-18 20:57:58 +02:00
exit_pool.nim rework spec imports (#2779) 2021-08-12 13:08:20 +00:00
forkedbeaconstate_dbhelpers.nim forkedbeaconstate_helpers -> forks (#2772) 2021-08-10 22:46:35 +02:00
spec_cache.nim rework spec imports (#2779) 2021-08-12 13:08:20 +00:00

README.md

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:

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)