## Issue Addressed
N/A
## Proposed Changes
Changes required for the `merge-devnet-3`. Added some more non substantive renames on top of @realbigsean 's commit.
Note: this doesn't include the proposer boosting changes in kintsugi v3.
This devnet isn't running with the proposer boosting fork choice changes so if we are looking to merge https://github.com/sigp/lighthouse/pull/2822 into `unstable`, then I think we should just maintain this branch for the devnet temporarily.
Co-authored-by: realbigsean <seananderson33@gmail.com>
Co-authored-by: Paul Hauner <paul@paulhauner.com>
## Issue Addressed
New rust lints
## Proposed Changes
- Boxing some enum variants
- removing some unused fields (is the validator lockfile unused? seemed so to me)
## Additional Info
- some error fields were marked as dead code but are logged out in areas
- left some dead fields in our ef test code because I assume they are useful for debugging?
Co-authored-by: realbigsean <seananderson33@gmail.com>
* 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>
* 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
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
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.
## Issue Addressed
NA
## Proposed Changes
This is a wholesale rip-off of #2708, see that PR for more of a description.
I've made this PR since @realbigsean is offline and I can't merge his PR due to Github's frustrating `target-branch-check` bug. I also changed the branch to `unstable`, since I'm trying to minimize the diff between `merge-f2f`/`unstable`. I'll just rebase `merge-f2f` onto `unstable` after this PR merges.
When running `make lint` I noticed the following warning:
```
warning: patch for `fixed-hash` uses the features mechanism. default-features and features will not take effect because the patch dependency does not support this mechanism
```
So, I removed the `features` section from the patch.
## Additional Info
NA
Co-authored-by: realbigsean <seananderson33@gmail.com>
## 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
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
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>
## Proposed Changes
Cache the total active balance for the current epoch in the `BeaconState`. Computing this value takes around 1ms, and this was negatively impacting block processing times on Prater, particularly when reconstructing states.
With a large number of attestations in each block, I saw the `process_attestations` function taking 150ms, which means that reconstructing hot states can take up to 4.65s (31 * 150ms), and reconstructing freezer states can take up to 307s (2047 * 150ms).
I opted to add the cache to the beacon state rather than computing the total active balance at the start of state processing and threading it through. Although this would be simpler in a way, it would waste time, particularly during block replay, as the total active balance doesn't change for the duration of an epoch. So we save ~32ms for hot states, and up to 8.1s for freezer states (using `--slots-per-restore-point 8192`).
## 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>
## Proposed Changes
* Consolidate Tokio versions: everything now uses the latest v1.10.0, no more `tokio-compat`.
* Many semver-compatible changes via `cargo update`. Notably this upgrades from the yanked v0.8.0 version of crossbeam-deque which is present in v1.5.0-rc.0
* Many semver incompatible upgrades via `cargo upgrades` and `cargo upgrade --workspace pkg_name`. Notable ommissions:
- Prometheus, to be handled separately: https://github.com/sigp/lighthouse/issues/2485
- `rand`, `rand_xorshift`: the libsecp256k1 package requires 0.7.x, so we'll stick with that for now
- `ethereum-types` is pinned at 0.11.0 because that's what `web3` is using and it seems nice to have just a single version
## Additional Info
We still have two versions of `libp2p-core` due to `discv5` depending on the v0.29.0 release rather than `master`. AFAIK it should be OK to release in this state (cc @AgeManning )
## Issue Addressed
N/A
## Proposed Changes
- Removing a bunch of unnecessary references
- Updated `Error::VariantError` to `Error::Variant`
- There were additional enum variant lints that I ignored, because I thought our variant names were fine
- removed `MonitoredValidator`'s `pubkey` field, because I couldn't find it used anywhere. It looks like we just use the string version of the pubkey (the `id` field) if there is no index
## Additional Info
Co-authored-by: realbigsean <seananderson33@gmail.com>
## Proposed Changes
Add the `sync_aggregate` from `BeaconBlock` to the bulk signature verifier for blocks. This necessitates a new signature set constructor for the sync aggregate, which is different from the others due to the use of [`eth2_fast_aggregate_verify`](https://github.com/ethereum/eth2.0-specs/blob/v1.1.0-alpha.7/specs/altair/bls.md#eth2_fast_aggregate_verify) for sync aggregates, per [`process_sync_aggregate`](https://github.com/ethereum/eth2.0-specs/blob/v1.1.0-alpha.7/specs/altair/beacon-chain.md#sync-aggregate-processing). I made the choice to return an optional signature set, with `None` representing the case where the signature is valid on account of being the point at infinity (requires no further checking).
To "dogfood" the changes and prevent duplication, the consensus logic now uses the signature set approach as well whenever it is required to verify signatures (which should only be in testing AFAIK). The EF tests pass with the code as it exists currently, but failed before I adapted the `eth2_fast_aggregate_verify` changes (which is good).
As a result of this change Altair block processing should be a little faster, and importantly, we will no longer accidentally verify signatures when replaying blocks, e.g. when replaying blocks from the database.
## Issue Addressed
NA
## Proposed Changes
This PR addresses two things:
1. Allows the `ValidatorMonitor` to work with Altair states.
1. Optimizes `altair::process_epoch` (see [code](https://github.com/paulhauner/lighthouse/blob/participation-cache/consensus/state_processing/src/per_epoch_processing/altair/participation_cache.rs) for description)
## Breaking Changes
The breaking changes in this PR revolve around one premise:
*After the Altair fork, it's not longer possible (given only a `BeaconState`) to identify if a validator had *any* attestation included during some epoch. The best we can do is see if that validator made the "timely" source/target/head flags.*
Whilst this seems annoying, it's not actually too bad. Finalization is based upon "timely target" attestations, so that's really the most important thing. Although there's *some* value in knowing if a validator had *any* attestation included, it's far more important to know about "timely target" participation, since this is what affects finality and justification.
For simplicity and consistency, I've also removed the ability to determine if *any* attestation was included from metrics and API endpoints. Now, all Altair and non-Altair states will simply report on the head/target attestations.
The following section details where we've removed fields and provides replacement values.
### Breaking Changes: Prometheus Metrics
Some participation metrics have been removed and replaced. Some were removed since they are no longer relevant to Altair (e.g., total attesting balance) and others replaced with gwei values instead of pre-computed values. This provides more flexibility at display-time (e.g., Grafana).
The following metrics were added as replacements:
- `beacon_participation_prev_epoch_head_attesting_gwei_total`
- `beacon_participation_prev_epoch_target_attesting_gwei_total`
- `beacon_participation_prev_epoch_source_attesting_gwei_total`
- `beacon_participation_prev_epoch_active_gwei_total`
The following metrics were removed:
- `beacon_participation_prev_epoch_attester`
- instead use `beacon_participation_prev_epoch_source_attesting_gwei_total / beacon_participation_prev_epoch_active_gwei_total`.
- `beacon_participation_prev_epoch_target_attester`
- instead use `beacon_participation_prev_epoch_target_attesting_gwei_total / beacon_participation_prev_epoch_active_gwei_total`.
- `beacon_participation_prev_epoch_head_attester`
- instead use `beacon_participation_prev_epoch_head_attesting_gwei_total / beacon_participation_prev_epoch_active_gwei_total`.
The `beacon_participation_prev_epoch_attester` endpoint has been removed. Users should instead use the pre-existing `beacon_participation_prev_epoch_target_attester`.
### Breaking Changes: HTTP API
The `/lighthouse/validator_inclusion/{epoch}/{validator_id}` endpoint loses the following fields:
- `current_epoch_attesting_gwei` (use `current_epoch_target_attesting_gwei` instead)
- `previous_epoch_attesting_gwei` (use `previous_epoch_target_attesting_gwei` instead)
The `/lighthouse/validator_inclusion/{epoch}/{validator_id}` endpoint lose the following fields:
- `is_current_epoch_attester` (use `is_current_epoch_target_attester` instead)
- `is_previous_epoch_attester` (use `is_previous_epoch_target_attester` instead)
- `is_active_in_current_epoch` becomes `is_active_unslashed_in_current_epoch`.
- `is_active_in_previous_epoch` becomes `is_active_unslashed_in_previous_epoch`.
## Additional Info
NA
## TODO
- [x] Deal with total balances
- [x] Update validator_inclusion API
- [ ] Ensure `beacon_participation_prev_epoch_target_attester` and `beacon_participation_prev_epoch_head_attester` work before Altair
Co-authored-by: realbigsean <seananderson33@gmail.com>
## Proposed Changes
Remove the remaining Altair `FIXME`s from consensus land.
1. Implement tree hash caching for the participation lists. This required some light type manipulation, including removing the `TreeHash` bound from `CachedTreeHash` which was purely descriptive.
2. Plumb the proposer index through Altair attestation processing, to avoid calculating it for _every_ attestation (potentially 128ms on large networks). This duplicates some work from #2431, but with the aim of getting it in sooner, particularly for the Altair devnets.
3. Removes two FIXMEs related to `superstruct` and cloning, which are unlikely to be particularly detrimental and will be tracked here instead: https://github.com/sigp/superstruct/issues/5
## Proposed Changes
Implement the consensus changes necessary for the upcoming Altair hard fork.
## Additional Info
This is quite a heavy refactor, with pivotal types like the `BeaconState` and `BeaconBlock` changing from structs to enums. This ripples through the whole codebase with field accesses changing to methods, e.g. `state.slot` => `state.slot()`.
Co-authored-by: realbigsean <seananderson33@gmail.com>
## Issue Addressed
Closes#2052
## Proposed Changes
- Refactor the attester/proposer duties endpoints in the BN
- Performance improvements
- Fixes some potential inconsistencies with the dependent root fields.
- Removes `http_api::beacon_proposer_cache` and just uses the one on the `BeaconChain` instead.
- Move the code for the proposer/attester duties endpoints into separate files, for readability.
- Refactor the `DutiesService` in the VC
- Required to reduce the delay on broadcasting new blocks.
- Gets rid of the `ValidatorDuty` shim struct that came about when we adopted the standard API.
- Separate block/attestation duty tasks so that they don't block each other when one is slow.
- In the VC, use `PublicKeyBytes` to represent validators instead of `PublicKey`. `PublicKey` is a legit crypto object whilst `PublicKeyBytes` is just a byte-array, it's much faster to clone/hash `PublicKeyBytes` and this change has had a significant impact on runtimes.
- Unfortunately this has created lots of dust changes.
- In the BN, store `PublicKeyBytes` in the `beacon_proposer_cache` and allow access to them. The HTTP API always sends `PublicKeyBytes` over the wire and the conversion from `PublicKey` -> `PublickeyBytes` is non-trivial, especially when queries have 100s/1000s of validators (like Pyrmont).
- Add the `state_processing::state_advance` mod which dedups a lot of the "apply `n` skip slots to the state" code.
- This also fixes a bug with some functions which were failing to include a state root as per [this comment](072695284f/consensus/state_processing/src/state_advance.rs (L69-L74)). I couldn't find any instance of this bug that resulted in anything more severe than keying a shuffling cache by the wrong block root.
- Swap the VC block service to use `mpsc` from `tokio` instead of `futures`. This is consistent with the rest of the code base.
~~This PR *reduces* the size of the codebase 🎉~~ It *used* to reduce the size of the code base before I added more comments.
## Observations on Prymont
- Proposer duties times down from peaks of 450ms to consistent <1ms.
- Current epoch attester duties times down from >1s peaks to a consistent 20-30ms.
- Block production down from +600ms to 100-200ms.
## Additional Info
- ~~Blocked on #2241~~
- ~~Blocked on #2234~~
## TODO
- [x] ~~Refactor this into some smaller PRs?~~ Leaving this as-is for now.
- [x] Address `per_slot_processing` roots.
- [x] Investigate slow next epoch times. Not getting added to cache on block processing?
- [x] Consider [this](072695284f/beacon_node/store/src/hot_cold_store.rs (L811-L812)) in the scenario of replacing the state roots
Co-authored-by: pawan <pawandhananjay@gmail.com>
Co-authored-by: Michael Sproul <michael@sigmaprime.io>
## Issue Addressed
Closes#1621
## Proposed Changes
Use the `disallowed_method` lint to ban uses of `Iterator::{sum,product}` from `types` and `state_processing`.
## Additional Info
The lint is turned off in the tree hash caching code, as it is performance sensitive and overflowy arithmetic is already allowed there.
## Issue Addressed
NA
## Proposed Changes
Add an optimization to perform `per_slot_processing` from the *leading-edge* of block processing to the *trailing-edge*. Ultimately, this allows us to import the block at slot `n` faster because we used the tail-end of slot `n - 1` to perform `per_slot_processing`.
Additionally, add a "block proposer cache" which allows us to cache the block proposer for some epoch. Since we're now doing trailing-edge `per_slot_processing`, we can prime this cache with the values for the next epoch before those blocks arrive (assuming those blocks don't have some weird forking).
There were several ancillary changes required to achieve this:
- Remove the `state_root` field of `BeaconSnapshot`, since there's no need to know it on a `pre_state` and in all other cases we can just read it from `block.state_root()`.
- This caused some "dust" changes of `snapshot.beacon_state_root` to `snapshot.beacon_state_root()`, where the `BeaconSnapshot::beacon_state_root()` func just reads the state root from the block.
- Rename `types::ShuffingId` to `AttestationShufflingId`. I originally did this because I added a `ProposerShufflingId` struct which turned out to be not so useful. I thought this new name was more descriptive so I kept it.
- Address https://github.com/ethereum/eth2.0-specs/pull/2196
- Add a debug log when we get a block with an unknown parent. There was previously no logging around this case.
- Add a function to `BeaconState` to compute all proposers for an epoch without re-computing the active indices for each slot.
## Additional Info
- ~~Blocked on #2173~~
- ~~Blocked on #2179~~ That PR was wrapped into this PR.
- There's potentially some places where we could avoid computing the proposer indices in `per_block_processing` but I haven't done this here. These would be an optimization beyond the issue at hand (improving block propagation times) and I think this PR is already doing enough. We can come back for that later.
## TODO
- [x] Tidy, improve comments.
- [x] ~~Try avoid computing proposer index in `per_block_processing`?~~
## Issue Addressed
NA
## Proposed Changes
Rust 1.50 has landed 🎉
The shiny new `clippy` peers down upon us mere mortals with disgust. Brutish peasants wrapping our `usize`s in superfluous `Option`s... tsk tsk.
I've performed the goat sacrifice and corrected our evil ways in this PR. Tonight we shall pray that Github Actions bestows the almighty green tick upon us.
## Additional Info
NA
Co-authored-by: realbigsean <seananderson33@gmail.com>
Co-authored-by: Michael Sproul <michael@sigmaprime.io>
## Issue Addressed
NA
## Proposed Changes
Reduces allocations by initializing the `pubkeys` vec to its final size. I doubt this will make a substantial difference, but it's nice to do it this way.
Seeing as `indexed_attestation.attesting_indices` has a [fixed length](e4b62139d7/consensus/types/src/indexed_attestation.rs (L22)), there's no real risk of a memory blow-up by pre-allocating the size of the `Vec`.
## Additional Info
NA
## Issue Addressed
- Resolves#2064
## Proposed Changes
Adds a `ValidatorMonitor` struct which provides additional logging and Grafana metrics for specific validators.
Use `lighthouse bn --validator-monitor` to automatically enable monitoring for any validator that hits the [subnet subscription](https://ethereum.github.io/eth2.0-APIs/#/Validator/prepareBeaconCommitteeSubnet) HTTP API endpoint.
Also, use `lighthouse bn --validator-monitor-pubkeys` to supply a list of validators which will always be monitored.
See the new docs included in this PR for more info.
## TODO
- [x] Track validator balance, `slashed` status, etc.
- [x] ~~Register slashings in current epoch, not offense epoch~~
- [ ] Publish Grafana dashboard, update TODO link in docs
- [x] ~~#2130 is merged into this branch, resolve that~~
## Issue Addressed
`test_dht_persistence` failing
## Proposed Changes
Bind `NetworkService::start` to an underscore prefixed variable rather than `_`. `_` was causing it to be dropped immediately
This was failing 5/100 times before this update, but I haven't been able to get it to fail after updating it
Co-authored-by: realbigsean <seananderson33@gmail.com>
## Proposed Changes
This quiets the slasher logs when ingesting slashings that are already known. Previously we would log an `ERRO` when a slashing was rediscovered locally but had already been submitted on-chain. This is to be expected from time to time, as different users' slashers will run at different times, and it's likely that slashings will make it on-chain before all users have detected them locally.
## Issue Addressed
NA
## Proposed Changes
Updates out of date dependencies.
## Additional Info
See also https://github.com/sigp/lighthouse/issues/1712 for a list of dependencies that are still out of date and the resasons.
## Issue Addressed
Resolves#1333
## Proposed Changes
- Remove `deposit_signature_set()` function
- Prevent deposits from being in `SignatureSets`
- User `Signature.verify()` to verify deposit signatures rather than a signature set which uses `fast_aggregate_verify()`
## Additional Info
n/a
## Issue Addressed
- Resolves#1706
## Proposed Changes
Updates dependencies across the workspace. Any crate that was not able to be brought to the latest version is listed in #1712.
## Additional Info
NA
## Proposed Changes
Update test vectors for v0.12.3, and introduced configurable `proportional_slashing_multiplier`.
Also makes `YamlConfig` a bit safer by making every field access in `apply_to_chain_spec` explicit, and removing the `#[serde(default)]` attribute, which would instantiate missing fields to type defaults! Risky!
## Issue Addressed
Resolves#1100
## Proposed Changes
* Implement the `SafeArith` trait for `Slot` and `Epoch`, so that methods like `safe_add` become available.
* Tweak the `SafeArith` trait to allow a different `Rhs` type (analagous to `std::ops::Add`, etc).
* Add a `legacy-arith` feature to `types` and `state_processing` that conditionally enables implementations of
the `std` ops with saturating semantics.
* Check compilation of `types` and `state_processing` _without_ `legacy-arith` on CI,
thus guaranteeing that they only use the `SafeArith` primitives 🎉
## Additional Info
The `legacy-arith` feature gets turned on by all higher-level crates that depend on `state_processing` or `types`, thus allowing the beacon chain, networking, and other components to continue to rely on the availability of ops like `+`, `-`, `*`, etc.
**This is a consensus-breaking change**, but brings us in line with the spec, and our incompatibilities shouldn't have been reachable with any valid configuration of Eth2 parameters.
## Issue Addressed
- Resolves#1080
## Proposed Changes
- Call `update_pubkey_cache` only in the `build_all_caches` method and `get_validator_index` method.
## Additional Info
This does reduce the number of places the cache is updated, making it simpler. But the `get_validator_index` method is used a couple times when we are iterating through the entire validator registry (or set of active validators). Before, we would only call `update_pubkey_cache` once before iterating through all validators. So I'm not _totally_ sure this change is worth it.
