Fix max packet sizes
Fix max_payload_size function
Add merge block test
Fix max size calculation; fix up test
Clear comments
Add a payload_size_function
Use safe arith for payload calculation
Return an error if block too big in block production
Separate test to check if block is over limit
* Fix fork choice after rebase
* Remove paulhauner warp dep
* Fix fork choice test compile errors
* Assume fork choice payloads are valid
* Add comment
* Ignore new tests
* Fix error in test skipping
* Fix arbitrary check kintsugi
* Add merge chain spec fields, and a function to determine which constant to use based on the state variant
* increment spec test version
* Remove `Transaction` enum wrapper
* Remove Transaction new-type
* Remove gas validations
* Add `--terminal-block-hash-epoch-override` flag
* Increment spec tests version to 1.1.5
* Remove extraneous gossip verification https://github.com/ethereum/consensus-specs/pull/2687
* - Remove unused Error variants
- Require both "terminal-block-hash-epoch-override" and "terminal-block-hash-override" when either flag is used
* - Remove a couple more unused Error variants
Co-authored-by: Paul Hauner <paul@paulhauner.com>
* update initializing from eth1 for merge genesis
* read execution payload header from file lcli
* add `create-payload-header` command to `lcli`
* fix base fee parsing
* Apply suggestions from code review
* default `execution_payload_header` bool to false when deserializing `meta.yml` in EF tests
Co-authored-by: Paul Hauner <paul@paulhauner.com>
* Add payload verification status to fork choice
* Pass payload verification status to import_block
* Add valid back-propagation
* Add head safety status latch to API
* Remove ExecutionLayerStatus
* Add execution info to client notifier
* Update notifier logs
* Change use of "hash" to refer to beacon block
* Shutdown on invalid finalized block
* Tidy, add comments
* Fix failing FC tests
* Allow blocks with unsafe head
* Fix forkchoiceUpdate call on startup
* Ignore payload errors
* Only return payload handle on valid response
* Push some engine logs down to debug
* Push ee fork choice log to debug
* Push engine call failure to debug
* Push some more errors to debug
* Fix panic at startup
* Reject some HTTP endpoints when EL is not ready
* Restrict more endpoints
* Add watchdog task
* Change scheduling
* Update to new schedule
* Add "syncing" concept
* Remove RequireSynced
* Add is_merge_complete to head_info
* Cache latest_head in Engines
* Call consensus_forkchoiceUpdate on startup
* Thread eth1_block_hash into interop genesis state
* Add merge-fork-epoch flag
* Build LH with minimal spec by default
* Add verbose logs to execution_layer
* Add --http-allow-sync-stalled flag
* Update lcli new-testnet to create genesis state
* Fix http test
* Fix compile errors in tests
* Start adding merge tests
* Expose MockExecutionLayer
* Add mock_execution_layer to BeaconChainHarness
* Progress with merge test
* Return more detailed errors with gas limit issues
* Use a better gas limit in block gen
* Ensure TTD is met in block gen
* Fix basic_merge tests
* Start geth testing
* Fix conflicts after rebase
* Remove geth tests
* Improve merge test
* Address clippy lints
* Make pow block gen a pure function
* Add working new test, breaking existing test
* Fix test names
* Add should_panic
* Don't run merge tests in debug
* Detect a tokio runtime when starting MockServer
* Fix clippy lint, include merge tests
* - Update the fork choice `ProtoNode` to include `is_merge_complete`
- Add database migration for the persisted fork choice
* update tests
* Small cleanup
* lints
* store execution block hash in fork choice rather than bool
Added Execution Payload from Rayonism Fork
Updated new Containers to match Merge Spec
Updated BeaconBlockBody for Merge Spec
Completed updating BeaconState and BeaconBlockBody
Modified ExecutionPayload<T> to use Transaction<T>
Mostly Finished Changes for beacon-chain.md
Added some things for fork-choice.md
Update to match new fork-choice.md/fork.md changes
ran cargo fmt
Added Missing Pieces in eth2_libp2p for Merge
fix ef test
Various Changes to Conform Closer to Merge Spec
## Issue Addressed
Closes#1996
## Proposed Changes
Run a second `Logger` via `sloggers` which logs to a file in the background with:
- separate `debug-level` for background and terminal logging
- the ability to limit log size
- rotation through a customizable number of log files
- an option to compress old log files (`.gz` format)
Add the following new CLI flags:
- `--logfile-debug-level`: The debug level of the log files
- `--logfile-max-size`: The maximum size of each log file
- `--logfile-max-number`: The number of old log files to store
- `--logfile-compress`: Whether to compress old log files
By default background logging uses the `debug` log level and saves logfiles to:
- Beacon Node: `$HOME/.lighthouse/$network/beacon/logs/beacon.log`
- Validator Client: `$HOME/.lighthouse/$network/validators/logs/validator.log`
Or, when using the `--datadir` flag:
`$datadir/beacon/logs/beacon.log` and `$datadir/validators/logs/validator.log`
Once rotated, old logs are stored like so: `beacon.log.1`, `beacon.log.2` etc.
> Note: `beacon.log.1` is always newer than `beacon.log.2`.
## Additional Info
Currently the default value of `--logfile-max-size` is 200 (MB) and `--logfile-max-number` is 5.
This means that the maximum storage space that the logs will take up by default is 1.2GB.
(200MB x 5 from old log files + <200MB the current logfile being written to)
Happy to adjust these default values to whatever people think is appropriate.
It's also worth noting that when logging to a file, we lose our custom `slog` formatting. This means the logfile logs look like this:
```
Oct 27 16:02:50.305 INFO Lighthouse started, version: Lighthouse/v2.0.1-8edd9d4+, module: lighthouse:413
Oct 27 16:02:50.305 INFO Configured for network, name: prater, module: lighthouse:414
```
## Issue Addressed
Resolves#2545
## Proposed Changes
Adds the long-overdue EF tests for fork choice. Although we had pretty good coverage via other implementations that closely followed our approach, it is nonetheless important for us to implement these tests too.
During testing I found that we were using a hard-coded `SAFE_SLOTS_TO_UPDATE_JUSTIFIED` value rather than one from the `ChainSpec`. This caused a failure during a minimal preset test. This doesn't represent a risk to mainnet or testnets, since the hard-coded value matched the mainnet preset.
## Failing Cases
There is one failing case which is presently marked as `SkippedKnownFailure`:
```
case 4 ("new_finalized_slot_is_justified_checkpoint_ancestor") from /home/paul/development/lighthouse/testing/ef_tests/consensus-spec-tests/tests/minimal/phase0/fork_choice/on_block/pyspec_tests/new_finalized_slot_is_justified_checkpoint_ancestor failed with NotEqual:
head check failed: Got Head { slot: Slot(40), root: 0x9183dbaed4191a862bd307d476e687277fc08469fc38618699863333487703e7 } | Expected Head { slot: Slot(24), root: 0x105b49b51bf7103c182aa58860b039550a89c05a4675992e2af703bd02c84570 }
```
This failure is due to #2741. It's not a particularly high priority issue at the moment, so we fix it after merging this PR.
## Issue Addressed
@paulhauner noticed that when we send head events, we use the block root from `new_head` in `fork_choice_internal`, but calculate `dependent_root` and `previous_dependent_root` using the `canonical_head`. This is normally fine because `new_head` updates the `canonical_head` in `fork_choice_internal`, but it's possible we have a reorg updating `canonical_head` before our head events are sent. So this PR ensures `dependent_root` and `previous_dependent_root` are always derived from the state associated with `new_head`.
Co-authored-by: realbigsean <seananderson33@gmail.com>
## Issue Addressed
Resolves#2612
## Proposed Changes
Implements both the checks mentioned in the original issue.
1. Verifies the `randao_reveal` in the beacon node
2. Cross checks the proposer index after getting back the block from the beacon node.
## Additional info
The block production time increases by ~10x because of the signature verification on the beacon node (based on the `beacon_block_production_process_seconds` metric) when running on a local testnet.
## Proposed Changes
Add several metrics for the number of attestations in the op pool. These give us a way to observe the number of valid, non-trivial attestations during block packing rather than just the size of the entire op pool.
## Issue Addressed
Mitigates #1096
## Proposed Changes
Add a flag to the beacon node called `--disable-lock-timeouts` which allows opting out of lock timeouts.
The lock timeouts serve a dual purpose:
1. They prevent any single operation from hogging the lock for too long. When a timeout occurs it logs a nasty error which indicates that there's suboptimal lock use occurring, which we can then act on.
2. They allow deadlock detection. We're fairly sure there are no deadlocks left in Lighthouse anymore but the timeout locks offer a safeguard against that.
However, timeouts on locks are not without downsides:
They allow for the possibility of livelock, particularly on slower hardware. If lock timeouts keep failing spuriously the node can be prevented from making any progress, even if it would be able to make progress slowly without the timeout. One particularly concerning scenario which could occur would be if a DoS attack succeeded in slowing block signature verification times across the network, and all Lighthouse nodes got livelocked because they timed out repeatedly. This could also occur on just a subset of nodes (e.g. dual core VPSs or Raspberri Pis).
By making the behaviour runtime configurable this PR allows us to choose the behaviour we want depending on circumstance. I suspect that long term we could make the timeout-free approach the default (#2381 moves in this direction) and just enable the timeouts on our testnet nodes for debugging purposes. This PR conservatively leaves the default as-is so we can gain some more experience before switching the default.
## Issue Addressed
NA
## Proposed Changes
Adds some more testing for Altair to the op pool. Credits to @michaelsproul for some appropriated efforts here.
## Additional Info
NA
Co-authored-by: Michael Sproul <michael@sigmaprime.io>
## Proposed Changes
Clone the proposer pubkeys during backfill signature verification to reduce the time that the pubkey cache lock is held for. Cloning such a small number of pubkeys has negligible impact on the total running time, but greatly reduces lock contention.
On a Ryzen 5950X, the setup step seems to take around 180us regardless of whether the key is cloned or not, while the verification takes 7ms. When Lighthouse is limited to 10% of one core using `sudo cpulimit --pid <pid> --limit 10` the total time jumps up to 800ms, but the setup step remains only 250us. This means that under heavy load this PR could cut the time the lock is held for from 800ms to 250us, which is a huge saving of 99.97%!
## Issue Addressed
NA
## Proposed Changes
This PR is near-identical to https://github.com/sigp/lighthouse/pull/2652, however it is to be merged into `unstable` instead of `merge-f2f`. Please see that PR for reasoning.
I'm making this duplicate PR to merge to `unstable` in an effort to shrink the diff between `unstable` and `merge-f2f` by doing smaller, lead-up PRs.
## Additional Info
NA
## Issue Addressed
Fix#2585
## Proposed Changes
Provide a canonical version of test_logger that can be used
throughout lighthouse.
## Additional Info
This allows tests to conditionally emit logging data by adding
test_logger as the default logger. And then when executing
`cargo test --features logging/test_logger` log output
will be visible:
wink@3900x:~/lighthouse/common/logging/tests/test-feature-test_logger (Add-test_logger-as-feature-to-logging)
$ cargo test --features logging/test_logger
Finished test [unoptimized + debuginfo] target(s) in 0.02s
Running unittests (target/debug/deps/test_logger-e20115db6a5e3714)
running 1 test
Sep 10 12:53:45.212 INFO hi, module: test_logger:8
test tests::test_fn_with_logging ... ok
test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
Doc-tests test-logger
running 0 tests
test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
Or, in normal scenarios where logging isn't needed, executing
`cargo test` the log output will not be visible:
wink@3900x:~/lighthouse/common/logging/tests/test-feature-test_logger (Add-test_logger-as-feature-to-logging)
$ cargo test
Finished test [unoptimized + debuginfo] target(s) in 0.02s
Running unittests (target/debug/deps/test_logger-02e02f8d41e8cf8a)
running 1 test
test tests::test_fn_with_logging ... ok
test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
Doc-tests test-logger
running 0 tests
test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
## Issue Addressed
This PR addresses an issue found by @YorickDowne during testing of v2.0.0-rc.0.
Due to a lack of atomic database writes on checkpoint sync start-up, it was possible for the database to get into an inconsistent state from which it couldn't recover without `--purge-db`. The core of the issue was that the store's anchor info was being stored _before_ the `PersistedBeaconChain`. If a crash occured so that anchor info was stored but _not_ the `PersistedBeaconChain`, then on restart Lighthouse would think the database was unitialized and attempt to compare-and-swap a `None` value, but would actually find the stale info from the previous run.
## Proposed Changes
The issue is fixed by writing the anchor info, the split point, and the `PersistedBeaconChain` atomically on start-up. Some type-hinting ugliness was required, which could possibly be cleaned up in future refactors.
## Issue Addressed
Closes#2528
## Proposed Changes
- Add `BlockTimesCache` to provide block timing information to `BeaconChain`. This allows additional metrics to be calculated for blocks that are set as head too late.
- Thread the `seen_timestamp` of blocks received from RPC responses (except blocks from syncing) through to the sync manager, similar to what is done for blocks from gossip.
## Additional Info
This provides the following additional metrics:
- `BEACON_BLOCK_OBSERVED_SLOT_START_DELAY_TIME`
- The delay between the start of the slot and when the block was first observed.
- `BEACON_BLOCK_IMPORTED_OBSERVED_DELAY_TIME`
- The delay between when the block was first observed and when the block was imported.
- `BEACON_BLOCK_HEAD_IMPORTED_DELAY_TIME`
- The delay between when the block was imported and when the block was set as head.
The metric `BEACON_BLOCK_IMPORTED_SLOT_START_DELAY_TIME` was removed.
A log is produced when a block is set as head too late, e.g.:
```
Aug 27 03:46:39.006 DEBG Delayed head block set_as_head_delay: Some(21.731066ms), imported_delay: Some(119.929934ms), observed_delay: Some(3.864596988s), block_delay: 4.006257988s, slot: 1931331, proposer_index: 24294, block_root: 0x937602c89d3143afa89088a44bdf4b4d0d760dad082abacb229495c048648a9e, service: beacon
```
## Issue Addressed
Resolves#2552
## Proposed Changes
Offers some improvement in inclusion distance calculation in the validator monitor.
When registering an attestation from a block, instead of doing `block.slot() - attesstation.data.slot()` to get the inclusion distance, we now pass the parent block slot from the beacon chain and do `parent_slot.saturating_sub(attestation.data.slot())`. This allows us to give best effort inclusion distance in scenarios where the attestation was included right after a skip slot. Note that this does not give accurate results in scenarios where the attestation was included few blocks after the skip slot.
In this case, if the attestation slot was `b1` and was included in block `b2` with a skip slot in between, we would get the inclusion delay as 0 (by ignoring the skip slot) which is the best effort inclusion delay.
```
b1 <- missed <- b2
```
Here, if the attestation slot was `b1` and was included in block `b3` with a skip slot and valid block `b2` in between, then we would get the inclusion delay as 2 instead of 1 (by ignoring the skip slot).
```
b1 <- missed <- b2 <- b3
```
A solution for the scenario 2 would be to count number of slots between included slot and attestation slot ignoring the skip slots in the beacon chain and pass the value to the validator monitor. But I'm concerned that it could potentially lead to db accesses for older blocks in extreme cases.
This PR also uses the validator monitor data for logging per epoch inclusion distance. This is useful as we won't get inclusion data in post-altair summaries.
Co-authored-by: Michael Sproul <micsproul@gmail.com>
## Issue Addressed
NA
## Proposed Changes
Implements the "union" type from the SSZ spec for `ssz`, `ssz_derive`, `tree_hash` and `tree_hash_derive` so it may be derived for `enums`:
https://github.com/ethereum/consensus-specs/blob/v1.1.0-beta.3/ssz/simple-serialize.md#union
The union type is required for the merge, since the `Transaction` type is defined as a single-variant union `Union[OpaqueTransaction]`.
### Crate Updates
This PR will (hopefully) cause CI to publish new versions for the following crates:
- `eth2_ssz_derive`: `0.2.1` -> `0.3.0`
- `eth2_ssz`: `0.3.0` -> `0.4.0`
- `eth2_ssz_types`: `0.2.0` -> `0.2.1`
- `tree_hash`: `0.3.0` -> `0.4.0`
- `tree_hash_derive`: `0.3.0` -> `0.4.0`
These these crates depend on each other, I've had to add a workspace-level `[patch]` for these crates. A follow-up PR will need to remove this patch, ones the new versions are published.
### Union Behaviors
We already had SSZ `Encode` and `TreeHash` derive for enums, however it just did a "transparent" pass-through of the inner value. Since the "union" decoding from the spec is in conflict with the transparent method, I've required that all `enum` have exactly one of the following enum-level attributes:
#### SSZ
- `#[ssz(enum_behaviour = "union")]`
- matches the spec used for the merge
- `#[ssz(enum_behaviour = "transparent")]`
- maintains existing functionality
- not supported for `Decode` (never was)
#### TreeHash
- `#[tree_hash(enum_behaviour = "union")]`
- matches the spec used for the merge
- `#[tree_hash(enum_behaviour = "transparent")]`
- maintains existing functionality
This means that we can maintain the existing transparent behaviour, but all existing users will get a compile-time error until they explicitly opt-in to being transparent.
### Legacy Option Encoding
Before this PR, we already had a union-esque encoding for `Option<T>`. However, this was with the *old* SSZ spec where the union selector was 4 bytes. During merge specification, the spec was changed to use 1 byte for the selector.
Whilst the 4-byte `Option` encoding was never used in the spec, we used it in our database. Writing a migrate script for all occurrences of `Option` in the database would be painful, especially since it's used in the `CommitteeCache`. To avoid the migrate script, I added a serde-esque `#[ssz(with = "module")]` field-level attribute to `ssz_derive` so that we can opt into the 4-byte encoding on a field-by-field basis.
The `ssz::legacy::four_byte_impl!` macro allows a one-liner to define the module required for the `#[ssz(with = "module")]` for some `Option<T> where T: Encode + Decode`.
Notably, **I have removed `Encode` and `Decode` impls for `Option`**. I've done this to force a break on downstream users. Like I mentioned, `Option` isn't used in the spec so I don't think it'll be *that* annoying. I think it's nicer than quietly having two different union implementations or quietly breaking the existing `Option` impl.
### Crate Publish Ordering
I've modified the order in which CI publishes crates to ensure that we don't publish a crate without ensuring we already published a crate that it depends upon.
## TODO
- [ ] Queue a follow-up `[patch]`-removing PR.
## Issue Addressed
NA
## Proposed Changes
Adds the ability to verify batches of aggregated/unaggregated attestations from the network.
When the `BeaconProcessor` finds there are messages in the aggregated or unaggregated attestation queues, it will first check the length of the queue:
- `== 1` verify the attestation individually.
- `>= 2` take up to 64 of those attestations and verify them in a batch.
Notably, we only perform batch verification if the queue has a backlog. We don't apply any artificial delays to attestations to try and force them into batches.
### Batching Details
To assist with implementing batches we modify `beacon_chain::attestation_verification` to have two distinct categories for attestations:
- *Indexed* attestations: those which have passed initial validation and were valid enough for us to derive an `IndexedAttestation`.
- *Verified* attestations: those attestations which were indexed *and also* passed signature verification. These are well-formed, interesting messages which were signed by validators.
The batching functions accept `n` attestations and then return `n` attestation verification `Result`s, where those `Result`s can be any combination of `Ok` or `Err`. In other words, we attempt to verify as many attestations as possible and return specific per-attestation results so peer scores can be updated, if required.
When we batch verify attestations, we first try to map all those attestations to *indexed* attestations. If any of those attestations were able to be indexed, we then perform batch BLS verification on those indexed attestations. If the batch verification succeeds, we convert them into *verified* attestations, disabling individual signature checking. If the batch fails, we convert to verified attestations with individual signature checking enabled.
Ultimately, we optimistically try to do a batch verification of attestation signatures and fall-back to individual verification if it fails. This opens an attach vector for "poisoning" the attestations and causing us to waste a batch verification. I argue that peer scoring should do a good-enough job of defending against this and the typical-case gains massively outweigh the worst-case losses.
## Additional Info
Before this PR, attestation verification took the attestations by value (instead of by reference). It turns out that this was unnecessary and, in my opinion, resulted in some undesirable ergonomics (e.g., we had to pass the attestation back in the `Err` variant to avoid clones). In this PR I've modified attestation verification so that it now takes a reference.
I refactored the `beacon_chain/tests/attestation_verification.rs` tests so they use a builder-esque "tester" struct instead of a weird macro. It made it easier for me to test individual/batch with the same set of tests and I think it was a nice tidy-up. Notably, I did this last to try and make sure my new refactors to *actual* production code would pass under the existing test suite.
## Issue Addressed
Closes#1891Closes#1784
## Proposed Changes
Implement checkpoint sync for Lighthouse, enabling it to start from a weak subjectivity checkpoint.
## Additional Info
- [x] Return unavailable status for out-of-range blocks requested by peers (#2561)
- [x] Implement sync daemon for fetching historical blocks (#2561)
- [x] Verify chain hashes (either in `historical_blocks.rs` or the calling module)
- [x] Consistency check for initial block + state
- [x] Fetch the initial state and block from a beacon node HTTP endpoint
- [x] Don't crash fetching beacon states by slot from the API
- [x] Background service for state reconstruction, triggered by CLI flag or API call.
Considered out of scope for this PR:
- Drop the requirement to provide the `--checkpoint-block` (this would require some pretty heavy refactoring of block verification)
Co-authored-by: Diva M <divma@protonmail.com>
## Issue Addressed
Related to: #2259
Made an attempt at all the necessary updates here to publish the crates to crates.io. I incremented the minor versions on all the crates that have been previously published. We still might run into some issues as we try to publish because I'm not able to test this out but I think it's a good starting point.
## Proposed Changes
- Add description and license to `ssz_types` and `serde_util`
- rename `serde_util` to `eth2_serde_util`
- increment minor versions
- remove path dependencies
- remove patch dependencies
## Additional Info
Crates published:
- [x] `tree_hash` -- need to publish `tree_hash_derive` and `eth2_hashing` first
- [x] `eth2_ssz_types` -- need to publish `eth2_serde_util` first
- [x] `tree_hash_derive`
- [x] `eth2_ssz`
- [x] `eth2_ssz_derive`
- [x] `eth2_serde_util`
- [x] `eth2_hashing`
Co-authored-by: realbigsean <seananderson33@gmail.com>
## Issue Addressed
N/A
## Proposed Changes
Add functionality in the validator monitor to provide sync committee related metrics for monitored validators.
Co-authored-by: Michael Sproul <michael@sigmaprime.io>
## Issue Addressed
NA
## Proposed Changes
Missed head votes on attestations is a well-known issue. The primary cause is a block getting set as the head *after* the attestation deadline.
This PR aims to shorten the overall time between "block received" and "block set as head" by:
1. Persisting the head and fork choice *after* setting the canonical head
- Informal measurements show this takes ~200ms
1. Pruning the op pool *after* setting the canonical head.
1. No longer persisting the op pool to disk during `BeaconChain::fork_choice`
- Informal measurements show this can take up to 1.2s.
I also add some metrics to help measure the effect of these changes.
Persistence changes like this run the risk of breaking assumptions downstream. However, I have considered these risks and I think we're fine here. I will describe my reasoning for each change.
## Reasoning
### Change 1: Persisting the head and fork choice *after* setting the canonical head
For (1), although the function is called `persist_head_and_fork_choice`, it only persists:
- Fork choice
- Head tracker
- Genesis block root
Since `BeaconChain::fork_choice_internal` does not modify these values between the original time we were persisting it and the current time, I assert that the change I've made is non-substantial in terms of what ends up on-disk. There's the possibility that some *other* thread has modified fork choice in the extra time we've given it, but that's totally fine.
Since the only time we *read* those values from disk is during startup, I assert that this has no impact during runtime.
### Change 2: Pruning the op pool after setting the canonical head
Similar to the argument above, we don't modify the op pool during `BeaconChain::fork_choice_internal` so it shouldn't matter when we prune. This change should be non-substantial.
### Change 3: No longer persisting the op pool to disk during `BeaconChain::fork_choice`
This change *is* substantial. With the proposed changes, we'll only be persisting the op pool to disk when we shut down cleanly (i.e., the `BeaconChain` gets dropped). This means we'll save disk IO and time during usual operation, but a `kill -9` or similar "crash" will probably result in an out-of-date op pool when we reboot. An out-of-date op pool can only have an impact when producing blocks or aggregate attestations/sync committees.
I think it's pretty reasonable that a crash might result in an out-of-date op pool, since:
- Crashes are fairly rare. Practically the only time I see LH suffer a full crash is when the OOM killer shows up, and that's a very serious event.
- It's generally quite rare to produce a block/aggregate immediately after a reboot. Just a few slots of runtime is probably enough to have a decent-enough op pool again.
## Additional Info
Credits to @macladson for the timings referenced here.
## Issue Addressed
Closes#2526
## Proposed Changes
If the head block fails to decode on start up, do two things:
1. Revert all blocks between the head and the most recent hard fork (to `fork_slot - 1`).
2. Reset fork choice so that it contains the new head, and all blocks back to the new head's finalized checkpoint.
## Additional Info
I tweaked some of the beacon chain test harness stuff in order to make it generic enough to test with a non-zero slot clock on start-up. In the process I consolidated all the various `new_` methods into a single generic one which will hopefully serve all future uses 🤞
