`LightClientUpdate` structures currently use different merkle proof root
depending on the presence of `finalized_header`. By always rooting it in
the same state (the `attested_header.state_root`), logic gets simpler.
Caveats:
- In periods of extended non-finality, `update.finalized_header` may now
be outdated by several sync committee periods. The old implementation
rejected such updates as the `next_sync_committee` in them was stale,
but the new implementation can properly handle this case.
- The `next_sync_committee` can no longer be considered finalized based
on `is_finality_update`. Instead, waiting until `finalized_header` is
in the `attested_header`'s sync committee period is now necessary.
- Because `update.finalized_header > store.finalized_header` no longer
holds (for updates with finality), an `is_better_update` helper is
added to improve `best_valid_update` tracking (in the past, finalized
updates with supermajority participation would always directly apply)
This PR builds on prior work from:
- @hwwhww at https://github.com/ethereum/consensus-specs/pull/2829
The existing README has a reference to an alias type `Bytes[N]` that has been removed from the repo so it is not clear what it exactly refers to.
This PR updates the type to the equivalent `List[T, N]` using more recent SSZ typing syntax.
Building merkle proofs is required functionality for implementing light
client sync. Although the spec currently only defines a function to
verify merkle proofs (`is_valid_merkle_branch`) there are still a few
PySpec unit tests that produce merkle proofs. This patch adds a new
generator to extract test vectors from those static unit tests, so that
light client implementations can validate their merkle proof logic.
Note that to execute on_attestation after on_block
Output more checking field
Disable mainnet config test_filtered_block_tree
Fix after rectoring + use more run_on_block
Fix and refactor `tick_and_run_on_attestation`
Etan Kissling
Alex Stokes
Hsiao-Wei Wang
Danny Ryan
protolambda
Dmitrii Shmatko
Mikhail Kalinin