* Support per slot state diffs
* Store HierarchyConfig on disk. Support storing hdiffs at per slot level.
* Revert HierachyConfig change for testing.
* Add validity check for the hierarchy config when opening the DB.
* Update HDiff tests.
* Fix `get_cold_state` panic when the diff for the slot isn't stored.
* Use slots instead of epochs for storing snapshots in freezer DB.
* Add snapshot buffer to `diff_buffer_cache` instead of loading it from db every time.
* Add `hierarchy-exponents` cli flag to beacon node.
* Add test for `StorageStrategy::ReplayFrom` and ignore a flaky test.
* Drop hierarchy_config in tests for more frequent snapshot and fix an issue where hdiff wasn't stored unless it's a epoch boundary slot.
## Issue Addressed
Fix a bug in the storage of the linear block roots array in the freezer DB. Previously this array was always written as part of state storage (or block backfill). With state pruning enabled by #4610, these states were no longer being written and as a result neither were the block roots.
The impact is quite low, we would just log an error when trying to forwards-iterate the block roots, which for validating nodes only happens when they try to look up blocks for peers:
> Aug 25 03:42:36.980 ERRO Missing chunk in forwards iterator chunk index: 49726, service: freezer_db
Any node checkpoint synced off `unstable` is affected and has a corrupt database. If you see the log above, you need to re-sync with the fix. Nodes that haven't checkpoint synced recently should _not_ be corrupted, even if they ran the buggy version.
## Proposed Changes
- Use a `ChunkWriter` to write the block roots when states are not being stored.
- Tweak the usage of `get_latest_restore_point` so that it doesn't return a nonsense value when state pruning is enabled.
- Tweak the guarantee on the block roots array so that block roots are assumed available up to the split slot (exclusive). This is a bit nicer than relying on anything to do with the latest restore point, which is a nonsensical concept when there aren't any restore points.
## Additional Info
I'm looking forward to deleting the chunked vector code for good when we merge tree-states 😁
## Issue Addressed
Closes#3210Closes#3211
## Proposed Changes
- Checkpoint sync from the latest finalized state regardless of its alignment.
- Add the `block_root` to the database's split point. This is _only_ added to the in-memory split in order to avoid a schema migration. See `load_split`.
- Add a new method to the DB called `get_advanced_state`, which looks up a state _by block root_, with a `state_root` as fallback. Using this method prevents accidental accesses of the split's unadvanced state, which does not exist in the hot DB and is not guaranteed to exist in the freezer DB at all. Previously Lighthouse would look up this state _from the freezer DB_, even if it was required for block/attestation processing, which was suboptimal.
- Replace several state look-ups in block and attestation processing with `get_advanced_state` so that they can't hit the split block's unadvanced state.
- Do not store any states in the freezer database by default. All states will be deleted upon being evicted from the hot database unless `--reconstruct-historic-states` is set. The anchor info which was previously used for checkpoint sync is used to implement this, including when syncing from genesis.
## Additional Info
Needs further testing. I want to stress-test the pruned database under Hydra.
The `get_advanced_state` method is intended to become more relevant over time: `tree-states` includes an identically named method that returns advanced states from its in-memory cache.
Co-authored-by: realbigsean <seananderson33@gmail.com>
## Issue Addressed
#4118
## Proposed Changes
This PR introduces a "progressive balances" cache on the `BeaconState`, which keeps track of the accumulated target attestation balance for the current & previous epochs. The cached values are utilised by fork choice to calculate unrealized justification and finalization (instead of converting epoch participation arrays to balances for each block we receive).
This optimization will be rolled out gradually to allow for more testing. A new `--progressive-balances disabled|checked|strict|fast` flag is introduced to support this:
- `checked`: enabled with checks against participation cache, and falls back to the existing epoch processing calculation if there is a total target attester balance mismatch. There is no performance gain from this as the participation cache still needs to be computed. **This is the default mode for now.**
- `strict`: enabled with checks against participation cache, returns error if there is a mismatch. **Used for testing only**.
- `fast`: enabled with no comparative checks and without computing the participation cache. This mode gives us the performance gains from the optimization. This is still experimental and not currently recommended for production usage, but will become the default mode in a future release.
- `disabled`: disable the usage of progressive cache, and use the existing method for FFG progression calculation. This mode may be useful if we find a bug and want to stop the frequent error logs.
### Tasks
- [x] Initial cache implementation in `BeaconState`
- [x] Perform checks in fork choice to compare the progressive balances cache against results from `ParticipationCache`
- [x] Add CLI flag, and disable the optimization by default
- [x] Testing on Goerli & Benchmarking
- [x] Move caching logic from state processing to the `ProgressiveBalancesCache` (see [this comment](https://github.com/sigp/lighthouse/pull/4362#discussion_r1230877001))
- [x] Add attesting balance metrics
Co-authored-by: Jimmy Chen <jimmy@sigmaprime.io>
## Issue Addressed
- #4293
- #4264
## Proposed Changes
*Changes largely follow those suggested in the main issue*.
- Add new routes to HTTP API
- `post_beacon_blocks_v2`
- `post_blinded_beacon_blocks_v2`
- Add new routes to `BeaconNodeHttpClient`
- `post_beacon_blocks_v2`
- `post_blinded_beacon_blocks_v2`
- Define new Eth2 common types
- `BroadcastValidation`, enum representing the level of validation to apply to blocks prior to broadcast
- `BroadcastValidationQuery`, the corresponding HTTP query string type for the above type
- ~~Define `_checked` variants of both `publish_block` and `publish_blinded_block` that enforce a validation level at a type level~~
- Add interactive tests to the `bn_http_api_tests` test target covering each validation level (to their own test module, `broadcast_validation_tests`)
- `beacon/blocks`
- `broadcast_validation=gossip`
- Invalid (400)
- Full Pass (200)
- Partial Pass (202)
- `broadcast_validation=consensus`
- Invalid (400)
- Only gossip (400)
- Only consensus pass (i.e., equivocates) (200)
- Full pass (200)
- `broadcast_validation=consensus_and_equivocation`
- Invalid (400)
- Invalid due to early equivocation (400)
- Only gossip (400)
- Only consensus (400)
- Pass (200)
- `beacon/blinded_blocks`
- `broadcast_validation=gossip`
- Invalid (400)
- Full Pass (200)
- Partial Pass (202)
- `broadcast_validation=consensus`
- Invalid (400)
- Only gossip (400)
- ~~Only consensus pass (i.e., equivocates) (200)~~
- Full pass (200)
- `broadcast_validation=consensus_and_equivocation`
- Invalid (400)
- Invalid due to early equivocation (400)
- Only gossip (400)
- Only consensus (400)
- Pass (200)
- Add a new trait, `IntoGossipVerifiedBlock`, which allows type-level guarantees to be made as to gossip validity
- Modify the structure of the `ObservedBlockProducers` cache from a `(slot, validator_index)` mapping to a `((slot, validator_index), block_root)` mapping
- Modify `ObservedBlockProducers::proposer_has_been_observed` to return a `SeenBlock` rather than a boolean on success
- Punish gossip peer (low) for submitting equivocating blocks
- Rename `BlockError::SlashablePublish` to `BlockError::SlashableProposal`
## Additional Info
This PR contains changes that directly modify how blocks are verified within the client. For more context, consult [comments in-thread](https://github.com/sigp/lighthouse/pull/4316#discussion_r1234724202).
Co-authored-by: Michael Sproul <michael@sigmaprime.io>
* Get tests passing
* Get benchmarks compiling
* Fix EF withdrawals test
* Remove unused deps
* Fix tree_hash panic in tests
* Fix slasher compilation
* Fix ssz_generic test
* Get more tests passing
* Fix EF tests for real
* Fix local testnet scripts
## Issue Addressed
Resolves#3238
## Proposed Changes
Please list or describe the changes introduced by this PR.
## Additional Info
Please provide any additional information. For example, future considerations
or information useful for reviewers.
## Issue Addressed
Closes#4332
## Proposed Changes
Remove the `CountUnrealized` type, defaulting unrealized justification to _on_. This fixes the #4332 issue by ensuring that importing the same block to fork choice always results in the same outcome.
Finalized sync speed may be slightly impacted by this change, but that is deemed an acceptable trade-off until the optimisation from #4118 is implemented.
TODO:
- [x] Also check that the block isn't a duplicate before importing
## Issue Addressed
NA
## Proposed Changes
Adds metrics to track validators that are submitting equivocating (but not slashable) sync messages. This follows on from some research we've been doing in a separate fork of LH.
## Additional Info
@jimmygchen and @michaelsproul have already run their eyes over this so it should be easy to get into v4.2.0, IMO.
## Issue Addressed
Closes https://github.com/sigp/lighthouse/issues/4291, part of #3613.
## Proposed Changes
- Implement the `el_offline` field on `/eth/v1/node/syncing`. We set `el_offline=true` if:
- The EL's internal status is `Offline` or `AuthFailed`, _or_
- The most recent call to `newPayload` resulted in an error (more on this in a moment).
- Use the `el_offline` field in the VC to mark nodes with offline ELs as _unsynced_. These nodes will still be used, but only after synced nodes.
- Overhaul the usage of `RequireSynced` so that `::No` is used almost everywhere. The `--allow-unsynced` flag was broken and had the opposite effect to intended, so it has been deprecated.
- Add tests for the EL being offline on the upcheck call, and being offline due to the newPayload check.
## Why track `newPayload` errors?
Tracking the EL's online/offline status is too coarse-grained to be useful in practice, because:
- If the EL is timing out to some calls, it's unlikely to timeout on the `upcheck` call, which is _just_ `eth_syncing`. Every failed call is followed by an upcheck [here](693886b941/beacon_node/execution_layer/src/engines.rs (L372-L380)), which would have the effect of masking the failure and keeping the status _online_.
- The `newPayload` call is the most likely to time out. It's the call in which ELs tend to do most of their work (often 1-2 seconds), with `forkchoiceUpdated` usually returning much faster (<50ms).
- If `newPayload` is failing consistently (e.g. timing out) then this is a good indication that either the node's EL is in trouble, or the network as a whole is. In the first case validator clients _should_ prefer other BNs if they have one available. In the second case, all of their BNs will likely report `el_offline` and they'll just have to proceed with trying to use them.
## Additional Changes
- Add utility method `ForkName::latest` which is quite convenient for test writing, but probably other things too.
- Delete some stale comments from when we used to support multiple execution nodes.
## Issue Addressed
Addresses #4238
## Proposed Changes
- [x] Add tests for the scenarios
- [x] Use the fork of the attestation slot for signature verification.
## Issue Addressed
Addresses #4234
## Proposed Changes
- Skip withdrawals processing in an inconsistent state replay.
- Repurpose `StateRootStrategy`: rename to `StateProcessingStrategy` and always skip withdrawals if using `StateProcessingStrategy::Inconsistent`
- Add a test to reproduce the scenario
Co-authored-by: Jimmy Chen <jimmy@sigmaprime.io>
## Issue Addressed
NA
## Proposed Changes
- Implements https://github.com/ethereum/consensus-specs/pull/3290/
- Bumps `ef-tests` to [v1.3.0-rc.4](https://github.com/ethereum/consensus-spec-tests/releases/tag/v1.3.0-rc.4).
The `CountRealizedFull` concept has been removed and the `--count-unrealized-full` and `--count-unrealized` BN flags now do nothing but log a `WARN` when used.
## Database Migration Debt
This PR removes the `best_justified_checkpoint` from fork choice. This field is persisted on-disk and the correct way to go about this would be to make a DB migration to remove the field. However, in this PR I've simply stubbed out the value with a junk value. I've taken this approach because if we're going to do a DB migration I'd love to remove the `Option`s around the justified and finalized checkpoints on `ProtoNode` whilst we're at it. Those options were added in #2822 which was included in Lighthouse v2.1.0. The options were only put there to handle the migration and they've been set to `Some` ever since v2.1.0. There's no reason to keep them as options anymore.
I started adding the DB migration to this branch but I started to feel like I was bloating this rather critical PR with nice-to-haves. I've kept the partially-complete migration [over in my repo](https://github.com/paulhauner/lighthouse/tree/fc-pr-18-migration) so we can pick it up after this PR is merged.
* Use eth1_withdrawal_credential in Some Test States
* Update beacon_node/genesis/src/interop.rs
Co-authored-by: Michael Sproul <micsproul@gmail.com>
* Update beacon_node/genesis/src/interop.rs
Co-authored-by: Michael Sproul <micsproul@gmail.com>
* Increase validator sizes
* Pick next sync committee message
Co-authored-by: Michael Sproul <micsproul@gmail.com>
Co-authored-by: Paul Hauner <paul@paulhauner.com>
## Issue Addressed
NA
## Proposed Changes
Myself and others (#3678) have observed that when running with lots of validators (e.g., 1000s) the cardinality is too much for Prometheus. I've seen Prometheus instances just grind to a halt when we turn the validator monitor on for our testnet validators (we have 10,000s of Goerli validators). Additionally, the debug log volume can get very high with one log per validator, per attestation.
To address this, the `bn --validator-monitor-individual-tracking-threshold <INTEGER>` flag has been added to *disable* per-validator (i.e., non-aggregated) metrics/logging once the validator monitor exceeds the threshold of validators. The default value is `64`, which is a finger-to-the-wind value. I don't actually know the value at which Prometheus starts to become overwhelmed, but I've seen it work with ~64 validators and I've seen it *not* work with 1000s of validators. A default of `64` seems like it will result in a breaking change to users who are running millions of dollars worth of validators whilst resulting in a no-op for low-validator-count users. I'm open to changing this number, though.
Additionally, this PR starts collecting aggregated Prometheus metrics (e.g., total count of head hits across all validators), so that high-validator-count validators still have some interesting metrics. We already had logging for aggregated values, so nothing has been added there.
I've opted to make this a breaking change since it can be rather damaging to your Prometheus instance to accidentally enable the validator monitor with large numbers of validators. I've crashed a Prometheus instance myself and had a report from another user who's done the same thing.
## Additional Info
NA
## Breaking Changes Note
A new label has been added to the validator monitor Prometheus metrics: `total`. This label tracks the aggregated metrics of all validators in the validator monitor (as opposed to each validator being tracking individually using its pubkey as the label).
Additionally, a new flag has been added to the Beacon Node: `--validator-monitor-individual-tracking-threshold`. The default value is `64`, which means that when the validator monitor is tracking more than 64 validators then it will stop tracking per-validator metrics and only track the `all_validators` metric. It will also stop logging per-validator logs and only emit aggregated logs (the exception being that exit and slashing logs are always emitted).
These changes were introduced in #3728 to address issues with untenable Prometheus cardinality and log volume when using the validator monitor with high validator counts (e.g., 1000s of validators). Users with less than 65 validators will see no change in behavior (apart from the added `all_validators` metric). Users with more than 65 validators who wish to maintain the previous behavior can set something like `--validator-monitor-individual-tracking-threshold 999999`.
## Proposed Changes
With proposer boosting implemented (#2822) we have an opportunity to re-org out late blocks.
This PR adds three flags to the BN to control this behaviour:
* `--disable-proposer-reorgs`: turn aggressive re-orging off (it's on by default).
* `--proposer-reorg-threshold N`: attempt to orphan blocks with less than N% of the committee vote. If this parameter isn't set then N defaults to 20% when the feature is enabled.
* `--proposer-reorg-epochs-since-finalization N`: only attempt to re-org late blocks when the number of epochs since finalization is less than or equal to N. The default is 2 epochs, meaning re-orgs will only be attempted when the chain is finalizing optimally.
For safety Lighthouse will only attempt a re-org under very specific conditions:
1. The block being proposed is 1 slot after the canonical head, and the canonical head is 1 slot after its parent. i.e. at slot `n + 1` rather than building on the block from slot `n` we build on the block from slot `n - 1`.
2. The current canonical head received less than N% of the committee vote. N should be set depending on the proposer boost fraction itself, the fraction of the network that is believed to be applying it, and the size of the largest entity that could be hoarding votes.
3. The current canonical head arrived after the attestation deadline from our perspective. This condition was only added to support suppression of forkchoiceUpdated messages, but makes intuitive sense.
4. The block is being proposed in the first 2 seconds of the slot. This gives it time to propagate and receive the proposer boost.
## Additional Info
For the initial idea and background, see: https://github.com/ethereum/consensus-specs/pull/2353#issuecomment-950238004
There is also a specification for this feature here: https://github.com/ethereum/consensus-specs/pull/3034
Co-authored-by: Michael Sproul <micsproul@gmail.com>
Co-authored-by: pawan <pawandhananjay@gmail.com>
## Issue Addressed
#3704
## Proposed Changes
Adds is_syncing_finalized: bool parameter for block verification functions. Sets the payload_verification_status to Optimistic if is_syncing_finalized is true. Uses SyncState in NetworkGlobals in BeaconProcessor to retrieve the syncing status.
## Additional Info
I could implement FinalizedSignatureVerifiedBlock if you think it would be nicer.
## Issue Addressed
Fix a bug in block production that results in blocks with 0 attestations during the first slot of an epoch.
The bug is marked by debug logs of the form:
> DEBG Discarding attestation because of missing ancestor, block_root: 0x3cc00d9c9e0883b2d0db8606278f2b8423d4902f9a1ee619258b5b60590e64f8, pivot_slot: 4042591
It occurs when trying to look up the shuffling decision root for an attestation from a slot which is prior to fork choice's finalized block. This happens frequently when proposing in the first slot of the epoch where we have:
- `current_epoch == n`
- `attestation.data.target.epoch == n - 1`
- attestation shuffling epoch `== n - 3` (decision block being the last block of `n - 3`)
- `state.finalized_checkpoint.epoch == n - 2` (first block of `n - 2` is finalized)
Hence the shuffling decision slot is out of range of the fork choice backwards iterator _by a single slot_.
Unfortunately this bug was hidden when we weren't pruning fork choice, and then reintroduced in v2.5.1 when we fixed the pruning (https://github.com/sigp/lighthouse/releases/tag/v2.5.1). There's no way to turn that off or disable the filtering in our current release, so we need a new release to fix this issue.
Fortunately, it also does not occur on every epoch boundary because of the gradual pruning of fork choice every 256 blocks (~8 epochs):
01e84b71f5/consensus/proto_array/src/proto_array_fork_choice.rs (L16)01e84b71f5/consensus/proto_array/src/proto_array.rs (L713-L716)
So the probability of proposing a 0-attestation block given a proposal assignment is approximately `1/32 * 1/8 = 0.39%`.
## Proposed Changes
- Load the block's shuffling ID from fork choice and verify it against the expected shuffling ID of the head state. This code was initially written before we had settled on a representation of shuffling IDs, so I think it's a nice simplification to make use of them here rather than more ad-hoc logic that fundamentally does the same thing.
## Additional Info
Thanks to @moshe-blox for noticing this issue and bringing it to our attention.
## Issue Addressed
Closes https://github.com/sigp/lighthouse/issues/2371
## Proposed Changes
Backport some changes from `tree-states` that remove duplicated calculations of the `proposer_index`.
With this change the proposer index should be calculated only once for each block, and then plumbed through to every place it is required.
## Additional Info
In future I hope to add more data to the consensus context that is cached on a per-epoch basis, like the effective balances of validators and the base rewards.
There are some other changes to remove indexing in tests that were also useful for `tree-states` (the `tree-states` types don't implement `Index`).
## Issue Addressed
NA
## Proposed Changes
This PR attempts to fix the following spurious CI failure:
```
---- store_tests::garbage_collect_temp_states_from_failed_block stdout ----
thread 'store_tests::garbage_collect_temp_states_from_failed_block' panicked at 'disk store should initialize: DBError { message: "Error { message: \"IO error: lock /tmp/.tmp6DcBQ9/cold_db/LOCK: already held by process\" }" }', beacon_node/beacon_chain/tests/store_tests.rs:59:10
```
I believe that some async task is taking a clone of the store and holding it in some other thread for a short time. This creates a race-condition when we try to open a new instance of the store.
## Additional Info
NA
## Issue Addressed
NA
## Proposed Changes
This PR removes duplicated block root computation.
Computing the `SignedBeaconBlock::canonical_root` has become more expensive since the merge as we need to compute the merke root of each transaction inside an `ExecutionPayload`.
Computing the root for [a mainnet block](https://beaconcha.in/slot/4704236) is taking ~10ms on my i7-8700K CPU @ 3.70GHz (no sha extensions). Given that our median seen-to-imported time for blocks is presently 300-400ms, removing a few duplicated block roots (~30ms) could represent an easy 10% improvement. When we consider that the seen-to-imported times include operations *after* the block has been placed in the early attester cache, we could expect the 30ms to be more significant WRT our seen-to-attestable times.
## Additional Info
NA
## Issue Addressed
Closes https://github.com/sigp/lighthouse/issues/3556
## Proposed Changes
Delete finalized execution payloads from the database in two places:
1. When running the finalization migration in `migrate_database`. We delete the finalized payloads between the last split point and the new updated split point. _If_ payloads are already pruned prior to this then this is sufficient to prune _all_ payloads as non-canonical payloads are already deleted by the head pruner, and all canonical payloads prior to the previous split will already have been pruned.
2. To address the fact that users will update to this code _after_ the merge on mainnet (and testnets), we need a one-off scan to delete the finalized payloads from the canonical chain. This is implemented in `try_prune_execution_payloads` which runs on startup and scans the chain back to the Bellatrix fork or the anchor slot (if checkpoint synced after Bellatrix). In the case where payloads are already pruned this check only imposes a single state load for the split state, which shouldn't be _too slow_. Even so, a flag `--prepare-payloads-on-startup=false` is provided to turn this off after it has run the first time, which provides faster start-up times.
There is also a new `lighthouse db prune_payloads` subcommand for users who prefer to run the pruning manually.
## Additional Info
The tests have been updated to not rely on finalized payloads in the database, instead using the `MockExecutionLayer` to reconstruct them. Additionally a check was added to `check_chain_dump` which asserts the non-existence or existence of payloads on disk depending on their slot.
## Proposed Changes
This PR has two aims: to speed up attestation packing in the op pool, and to fix bugs in the verification of attester slashings, proposer slashings and voluntary exits. The changes are bundled into a single database schema upgrade (v12).
Attestation packing is sped up by removing several inefficiencies:
- No more recalculation of `attesting_indices` during packing.
- No (unnecessary) examination of the `ParticipationFlags`: a bitfield suffices. See `RewardCache`.
- No re-checking of attestation validity during packing: the `AttestationMap` provides attestations which are "correct by construction" (I have checked this using Hydra).
- No SSZ re-serialization for the clunky `AttestationId` type (it can be removed in a future release).
So far the speed-up seems to be roughly 2-10x, from 500ms down to 50-100ms.
Verification of attester slashings, proposer slashings and voluntary exits is fixed by:
- Tracking the `ForkVersion`s that were used to verify each message inside the `SigVerifiedOp`. This allows us to quickly re-verify that they match the head state's opinion of what the `ForkVersion` should be at the epoch(s) relevant to the message.
- Storing the `SigVerifiedOp` on disk rather than the raw operation. This allows us to continue track the fork versions after a reboot.
This is mostly contained in this commit 52bb1840ae.
## Additional Info
The schema upgrade uses the justified state to re-verify attestations and compute `attesting_indices` for them. It will drop any attestations that fail to verify, by the logic that attestations are most valuable in the few slots after they're observed, and are probably stale and useless by the time a node restarts. Exits and proposer slashings and similarly re-verified to obtain `SigVerifiedOp`s.
This PR contains a runtime killswitch `--paranoid-block-proposal` which opts out of all the optimisations in favour of closely verifying every included message. Although I'm quite sure that the optimisations are correct this flag could be useful in the event of an unforeseen emergency.
Finally, you might notice that the `RewardCache` appears quite useless in its current form because it is only updated on the hot-path immediately before proposal. My hope is that in future we can shift calls to `RewardCache::update` into the background, e.g. while performing the state advance. It is also forward-looking to `tree-states` compatibility, where iterating and indexing `state.{previous,current}_epoch_participation` is expensive and needs to be minimised.
## Issue Addressed
Resolves#3379
## Proposed Changes
Remove instances of `InvalidTerminalBlock` in lighthouse and use
`Invalid {latest_valid_hash: "0x0000000000000000000000000000000000000000000000000000000000000000"}`
to represent that status.
## Proposed Changes
Update the invalid head tests so that they work with the current default fork choice configuration.
Thanks @realbigsean for fixing the persistence test and the EF tests.
Co-authored-by: realbigsean <sean@sigmaprime.io>
## Issue Addressed
NA
## Proposed Changes
This PR will make Lighthouse return blocks with invalid payloads via the API with `execution_optimistic = true`. This seems a bit awkward, however I think it's better than returning a 404 or some other error.
Let's consider the case where the only possible head is invalid (#3370 deals with this). In such a scenario all of the duties endpoints will start failing because the head is invalid. I think it would be better if the duties endpoints continue to work, because it's likely that even though the head is invalid the duties are still based upon valid blocks and we want the VC to have them cached. There's no risk to the VC here because we won't actually produce an attestation pointing to an invalid head.
Ultimately, I don't think it's particularly important for us to distinguish between optimistic and invalid blocks on the API. Neither should be trusted and the only *real* reason that we track this is so we can try and fork around the invalid blocks.
## Additional Info
- ~~Blocked on #3370~~
## Issue Addressed
NA
## Proposed Changes
There are scenarios where the only viable head will have an invalid execution payload, in this scenario the `get_head` function on `proto_array` will return an error. We must recover from this scenario by importing blocks from the network.
This PR stops `BeaconChain::recompute_head` from returning an error so that we can't accidentally start down-scoring peers or aborting block import just because the current head has an invalid payload.
## Reviewer Notes
The following changes are included:
1. Allow `fork_choice.get_head` to fail gracefully in `BeaconChain::process_block` when trying to update the `early_attester_cache`; simply don't add the block to the cache rather than aborting the entire process.
1. Don't return an error from `BeaconChain::recompute_head_at_current_slot` and `BeaconChain::recompute_head` to defensively prevent calling functions from aborting any process just because the fork choice function failed to run.
- This should have practically no effect, since most callers were still continuing if recomputing the head failed.
- The outlier is that the API will return 200 rather than a 500 when fork choice fails.
1. Add the `ProtoArrayForkChoice::set_all_blocks_to_optimistic` function to recover from the scenario where we've rebooted and the persisted fork choice has an invalid head.
## Issue Addressed
Add a flag that optionally enables unrealized vote tracking. Would like to test out on testnets and benchmark differences in methods of vote tracking. This PR includes a DB schema upgrade to enable to new vote tracking style.
Co-authored-by: realbigsean <sean@sigmaprime.io>
Co-authored-by: Paul Hauner <paul@paulhauner.com>
Co-authored-by: sean <seananderson33@gmail.com>
Co-authored-by: Mac L <mjladson@pm.me>
## Issue Addressed
Resolves#3316
## Proposed Changes
This PR fixes an issue where lighthouse created a transition block with `block.execution_payload().timestamp == terminal_block.timestamp` if the terminal block was created at the slot boundary.
## Issue Addressed
NA
## Proposed Changes
After some discussion in Discord with @mkalinin it was raised that it was not the intention of the engine API to have CLs validate the `latest_valid_hash` (LVH) and all ancestors.
Whilst I believe the engine API is being updated such that the LVH *must* identify a valid hash or be set to some junk value, I'm not confident that we can rely upon the LVH as being valid (at least for now) due to the confusion surrounding it.
Being able to validate blocks via the LVH is a relatively minor optimisation; if the LVH value ends up becoming our head we'll send an fcU and get the VALID status there.
Falsely marking a block as valid has serious consequences and since it's a minor optimisation to use LVH I think that we don't take the risk.
For clarity, we will still *invalidate* the *descendants* of the LVH, we just wont *validate* the *ancestors*.
## Additional Info
NA
