* electra attestation updates
In Electra, we have two attestation formats: on-chain and on-network -
the former combines all committees of a slot in a single committee bit
list.
This PR makes a number of cleanups to move towards fixing this -
attestation packing however still needs to be fixed as it currently
creates attestations with a single committee only which is very
inefficient.
* more attestations in the blocks
* signing and aggregation fixes
* tool fix
* test, import
Add support for using era file for the initial checkpoint block.
This should also avoid an error when the beacon node is restarted
before the backfill process has made any progress (#6059).
When initializing from a state that's not aligned to an epoch boundary,
an earlier state is loaded that's epoch aligned, and subsequently topped
up with the missing blocks. `dag.headSyncCommittee` is initialized prior
to topping up the missing blocks, though. If the sync committee changes
while applying the blocks (e.g., a sync committee period boundary hits),
the cached information becomes unlinked from `dag.head`, leading to
valid blocks based on that chain being rejected. To fix this, move cache
initialization after the top up with blocks. This has been observed on
Goerli by initializing from 7919502 and attempting to top up 7920111.
The block gets rejected with an invalid state root on nodes that have
restarted after setting 7920111 as head, while it gets accepted by all
other nodes. Error message is `block: state root verification failed`.
The incorrect initialization behaviour was introduced in #4592, before
which the sync committee cache was initialized after applying blocks.
`batchVerify`'s precondition is a non-empty signature list:
```nim
if input.len == 0:
# Spec precondition
return false
```
This means that in eras without any blocks (as has happened on Goerli),
calling it leads to era files being reported as invalid.
Using a dedicated branch for researching the effectiveness of split view
scenario handling simplifies testing and avoids having partial work on
`unstable`. If we want, we can reintroduce it under a `--debug` flag at
a later time. But for now, Goerli is a rare opoprtunity to test this,
maybe just for another week or so.
- https://github.com/status-im/infra-nimbus/pull/179
In split view situation, the canonical chain may only be served by a
tiny amount of peers, and branches may span long durations. Minority
branches may still have a large weight from attestations and should
be discovered. To assist with that, add a branch discovery module that
assists in such a situation by specifically targeting peers with unknown
histories and downloading from them, in addition to sync manager work
which handles popular branches.
There are situations where all states in the `blockchain_dag` are
occupied and cannot be borrowed.
- headState: Many assumptions in the code that it cannot be advanced
- clearanceState: Resets every time a new block gets imported, including
blocks from non-canonical branches
- epochRefState: Used even more frequently than clearanceState
This means that during the catch-up mechanic where the head state is
slowly advanced to wall clock to catch up on validator duties in the
situation where the canonical head is way behind non-canonical heads,
we cannot use any of the three existing states. In that situation,
Nimbus already consumes an increased amount of memory due to all the
`BlockRef`, fork choice states and so on, so experience is degraded.
It seems reasonable to allocate a fourth state temporarily during that
mechanic, until a new proposal could be made on the canonical chain.
Note that currently, on `unstable`, proposals _do_ happen every couple
hours because sync manager doesn't manage to discover additional heads
in a split-view scenario on Goerli. However, with the branch discovery
module, new blocks are discovered all the time, and the clearanceState
may no longer be borrowed as it is reset to different branch too often.
The extra state could also find other uses in the future, e.g., for
incremental computations as in reindexing the database, or online
collection of historical light client data.
Use the same eviction policy for blocks as already the case for blobs.
FIFO makes more sense, because it favors keeping ancestors of blocks
which need to be applied to the DAG before their children get eligible.
Agnish Ghosh
tersec
Jacek Sieka
Etan Kissling