* Attestation superstruct changes for EIP 7549 (#5644)
* update
* experiment
* superstruct changes
* revert
* superstruct changes
* fix tests
* indexed attestation
* indexed attestation superstruct
* updated TODOs
* `superstruct` the `AttesterSlashing` (#5636)
* `superstruct` Attester Fork Variants
* Push a little further
* Deal with Encode / Decode of AttesterSlashing
* not so sure about this..
* Stop Encode/Decode Bounds from Propagating Out
* Tons of Changes..
* More Conversions to AttestationRef
* Add AsReference trait (#15)
* Add AsReference trait
* Fix some snafus
* Got it Compiling! :D
* Got Tests Building
* Get beacon chain tests compiling
---------
Co-authored-by: Michael Sproul <micsproul@gmail.com>
* Merge remote-tracking branch 'upstream/unstable' into electra_attestation_changes
* Make EF Tests Fork-Agnostic (#5713)
* Finish EF Test Fork Agnostic (#5714)
* Superstruct `AggregateAndProof` (#5715)
* Upgrade `superstruct` to `0.8.0`
* superstruct `AggregateAndProof`
* Merge remote-tracking branch 'sigp/unstable' into electra_attestation_changes
* cargo fmt
* Merge pull request #5726 from realbigsean/electra_attestation_changes
Merge unstable into Electra attestation changes
* EIP7549 `get_attestation_indices` (#5657)
* get attesting indices electra impl
* fmt
* get tests to pass
* fmt
* fix some beacon chain tests
* fmt
* fix slasher test
* fmt got me again
* fix more tests
* fix tests
* Some small changes (#5739)
* cargo fmt (#5740)
* Sketch op pool changes
* fix get attesting indices (#5742)
* fix get attesting indices
* better errors
* fix compile
* only get committee index once
* Ef test fixes (#5753)
* attestation related ef test fixes
* delete commented out stuff
* Fix Aggregation Pool for Electra (#5754)
* Fix Aggregation Pool for Electra
* Remove Outdated Interface
* fix ssz (#5755)
* Get `electra_op_pool` up to date (#5756)
* fix get attesting indices (#5742)
* fix get attesting indices
* better errors
* fix compile
* only get committee index once
* Ef test fixes (#5753)
* attestation related ef test fixes
* delete commented out stuff
* Fix Aggregation Pool for Electra (#5754)
* Fix Aggregation Pool for Electra
* Remove Outdated Interface
* fix ssz (#5755)
---------
Co-authored-by: realbigsean <sean@sigmaprime.io>
* Revert "Get `electra_op_pool` up to date (#5756)" (#5757)
This reverts commit ab9e58aa3d.
* Merge branch 'electra_attestation_changes' of https://github.com/sigp/lighthouse into electra_op_pool
* Compute on chain aggregate impl (#5752)
* add compute_on_chain_agg impl to op pool changes
* fmt
* get op pool tests to pass
* update the naive agg pool interface (#5760)
* Fix bugs in cross-committee aggregation
* Add comment to max cover optimisation
* Fix assert
* Merge pull request #5749 from sigp/electra_op_pool
Optimise Electra op pool aggregation
* update committee offset
* Fix Electra Fork Choice Tests (#5764)
* Subscribe to the correct subnets for electra attestations (#5782)
* subscribe to the correct att subnets for electra
* subscribe to the correct att subnets for electra
* cargo fmt
* fix slashing handling
* Merge remote-tracking branch 'upstream/unstable'
* Send unagg attestation based on fork
* Publish all aggregates
* just one more check bro plz..
* Merge pull request #5832 from ethDreamer/electra_attestation_changes_merge_unstable
Merge `unstable` into `electra_attestation_changes`
* Merge pull request #5835 from realbigsean/fix-validator-logic
Fix validator logic
* Merge pull request #5816 from realbigsean/electra-attestation-slashing-handling
Electra slashing handling
* Electra attestation changes rm decode impl (#5856)
* Remove Crappy Decode impl for Attestation
* Remove Inefficient Attestation Decode impl
* Implement Schema Upgrade / Downgrade
* Update beacon_node/beacon_chain/src/schema_change/migration_schema_v20.rs
Co-authored-by: Michael Sproul <micsproul@gmail.com>
---------
Co-authored-by: Michael Sproul <micsproul@gmail.com>
* Fix failing attestation tests and misc electra attestation cleanup (#5810)
* - get attestation related beacon chain tests to pass
- observed attestations are now keyed off of data + committee index
- rename op pool attestationref to compactattestationref
- remove unwraps in agg pool and use options instead
- cherry pick some changes from ef-tests-electra
* cargo fmt
* fix failing test
* Revert dockerfile changes
* make committee_index return option
* function args shouldnt be a ref to attestation ref
* fmt
* fix dup imports
---------
Co-authored-by: realbigsean <seananderson33@GMAIL.com>
* fix some todos (#5817)
* Merge branch 'unstable' of https://github.com/sigp/lighthouse into electra_attestation_changes
* add consolidations to merkle calc for inclusion proof
* Remove Duplicate KZG Commitment Merkle Proof Code (#5874)
* Remove Duplicate KZG Commitment Merkle Proof Code
* s/tree_lists/fields/
* Merge branch 'unstable' of https://github.com/sigp/lighthouse into electra_attestation_changes
* fix compile
* Fix slasher tests (#5906)
* Fix electra tests
* Add electra attestations to double vote tests
* Update superstruct to 0.8
* Merge remote-tracking branch 'origin/unstable' into electra_attestation_changes
* Small cleanup in slasher tests
* Clean up Electra observed aggregates (#5929)
* Use consistent key in observed_attestations
* Remove unwraps from observed aggregates
* Merge branch 'unstable' of https://github.com/sigp/lighthouse into electra_attestation_changes
* De-dup attestation constructor logic
* Remove unwraps in Attestation construction
* Dedup match_attestation_data
* Remove outdated TODO
* Use ForkName Ord in fork-choice tests
* Use ForkName Ord in BeaconBlockBody
* Make to_electra not fallible
* Remove TestRandom impl for IndexedAttestation
* Remove IndexedAttestation faulty Decode impl
* Drop TestRandom impl
* Add PendingAttestationInElectra
* Indexed att on disk (#35)
* indexed att on disk
* fix lints
* Update slasher/src/migrate.rs
Co-authored-by: ethDreamer <37123614+ethDreamer@users.noreply.github.com>
---------
Co-authored-by: Lion - dapplion <35266934+dapplion@users.noreply.github.com>
Co-authored-by: ethDreamer <37123614+ethDreamer@users.noreply.github.com>
* add electra fork enabled fn to ForkName impl (#36)
* add electra fork enabled fn to ForkName impl
* remove inadvertent file
* Update common/eth2/src/types.rs
Co-authored-by: ethDreamer <37123614+ethDreamer@users.noreply.github.com>
* Dedup attestation constructor logic in attester cache
* Use if let Ok for committee_bits
* Dedup Attestation constructor code
* Diff reduction in tests
* Fix beacon_chain tests
* Diff reduction
* Use Ord for ForkName in pubsub
* Resolve into_attestation_and_indices todo
* Remove stale TODO
* Fix beacon_chain tests
* Test spec invariant
* Use electra_enabled in pubsub
* Remove get_indexed_attestation_from_signed_aggregate
* Use ok_or instead of if let else
* committees are sorted
* remove dup method `get_indexed_attestation_from_committees`
* Merge pull request #5940 from dapplion/electra_attestation_changes_lionreview
Electra attestations #5712 review
* update default persisted op pool deserialization
* ensure aggregate and proof uses serde untagged on ref
* Fork aware ssz static attestation tests
* Electra attestation changes from Lions review (#5971)
* dedup/cleanup and remove unneeded hashset use
* remove irrelevant TODOs
* Merge branch 'unstable' of https://github.com/sigp/lighthouse into electra_attestation_changes
* Electra attestation changes sean review (#5972)
* instantiate empty bitlist in unreachable code
* clean up error conversion
* fork enabled bool cleanup
* remove a couple todos
* return bools instead of options in `aggregate` and use the result
* delete commented out code
* use map macros in simple transformations
* remove signers_disjoint_from
* get ef tests compiling
* get ef tests compiling
* update intentionally excluded files
* Avoid changing slasher schema for Electra
* Delete slasher schema v4
* Fix clippy
* Fix compilation of beacon_chain tests
* Update database.rs
* Add electra lightclient types
* Update slasher/src/database.rs
* fix imports
* Merge pull request #5980 from dapplion/electra-lightclient
Add electra lightclient types
* Merge pull request #5975 from michaelsproul/electra-slasher-no-migration
Avoid changing slasher schema for Electra
* Update beacon_node/beacon_chain/src/attestation_verification.rs
* Update beacon_node/beacon_chain/src/attestation_verification.rs
* max_value -> MAX
* remove unnecesary closures
* a couple more max_value -> MAX
* a couple more max_value -> MAX
* Revert "a couple more max_value -> MAX"
This reverts commit 807fe7cae9.
* unused spec field -> phantom data
* ignore some dead code warnings
* update kurtosis repo location
## Issue Addressed
Addresses the recent CI failures caused by caching `blst` for the wrong CPU type.
## Proposed Changes
- Use `FEATURES: jemalloc,portable` when building Lighthouse & `lcli` in tests
- Add a new `TEST_FEATURES` and set to `portable` for all CI test jobs.
- Updated Makefiles to read the `TEST_FEATURES` environment variable, and default to none.
## Issue Addressed
Synchronize dependencies and edition on the workspace `Cargo.toml`
## Proposed Changes
with https://github.com/rust-lang/cargo/issues/8415 merged it's now possible to synchronize details on the workspace `Cargo.toml` like the metadata and dependencies.
By only having dependencies that are shared between multiple crates aligned on the workspace `Cargo.toml` it's easier to not miss duplicate versions of the same dependency and therefore ease on the compile times.
## Additional Info
this PR also removes the no longer required direct dependency of the `serde_derive` crate.
should be reviewed after https://github.com/sigp/lighthouse/pull/4639 get's merged.
closes https://github.com/sigp/lighthouse/issues/4651
Co-authored-by: Michael Sproul <michael@sigmaprime.io>
Co-authored-by: Michael Sproul <micsproul@gmail.com>
## Issue Addressed
NA
## Proposed Changes
Similar to #4181 but without the version bump and a more nuanced fix.
Patches the high CPU usage seen after the Capella fork which was caused by processing exits when there are skip slots.
## Additional Info
~~This is an imperfect solution that will cause us to drop some exits at the fork boundary. This is tracked at #4184.~~
* Add first efforts at broadcast
* Tidy
* Move broadcast code to client
* Progress with broadcast impl
* Rename to address change
* Fix compile errors
* Use `while` loop
* Tidy
* Flip broadcast condition
* Switch to forgetting individual indices
* Always broadcast when the node starts
* Refactor into two functions
* Add testing
* Add another test
* Tidy, add more testing
* Tidy
* Add test, rename enum
* Rename enum again
* Tidy
* Break loop early
* Add V15 schema migration
* Bump schema version
* Progress with migration
* Update beacon_node/client/src/address_change_broadcast.rs
Co-authored-by: Michael Sproul <micsproul@gmail.com>
* Fix typo in function name
---------
Co-authored-by: Michael Sproul <micsproul@gmail.com>
* Import BLS to execution changes before Capella
* Test for BLS to execution change HTTP API
* Pack BLS to execution changes in LIFO order
* Remove unused var
* Clippy
## Issue Addressed
New lints for rust 1.65
## Proposed Changes
Notable change is the identification or parameters that are only used in recursion
## Additional Info
na
## 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.
## Overview
This rather extensive PR achieves two primary goals:
1. Uses the finalized/justified checkpoints of fork choice (FC), rather than that of the head state.
2. Refactors fork choice, block production and block processing to `async` functions.
Additionally, it achieves:
- Concurrent forkchoice updates to the EL and cache pruning after a new head is selected.
- Concurrent "block packing" (attestations, etc) and execution payload retrieval during block production.
- Concurrent per-block-processing and execution payload verification during block processing.
- The `Arc`-ification of `SignedBeaconBlock` during block processing (it's never mutated, so why not?):
- I had to do this to deal with sending blocks into spawned tasks.
- Previously we were cloning the beacon block at least 2 times during each block processing, these clones are either removed or turned into cheaper `Arc` clones.
- We were also `Box`-ing and un-`Box`-ing beacon blocks as they moved throughout the networking crate. This is not a big deal, but it's nice to avoid shifting things between the stack and heap.
- Avoids cloning *all the blocks* in *every chain segment* during sync.
- It also has the potential to clean up our code where we need to pass an *owned* block around so we can send it back in the case of an error (I didn't do much of this, my PR is already big enough 😅)
- The `BeaconChain::HeadSafetyStatus` struct was removed. It was an old relic from prior merge specs.
For motivation for this change, see https://github.com/sigp/lighthouse/pull/3244#issuecomment-1160963273
## Changes to `canonical_head` and `fork_choice`
Previously, the `BeaconChain` had two separate fields:
```
canonical_head: RwLock<Snapshot>,
fork_choice: RwLock<BeaconForkChoice>
```
Now, we have grouped these values under a single struct:
```
canonical_head: CanonicalHead {
cached_head: RwLock<Arc<Snapshot>>,
fork_choice: RwLock<BeaconForkChoice>
}
```
Apart from ergonomics, the only *actual* change here is wrapping the canonical head snapshot in an `Arc`. This means that we no longer need to hold the `cached_head` (`canonical_head`, in old terms) lock when we want to pull some values from it. This was done to avoid deadlock risks by preventing functions from acquiring (and holding) the `cached_head` and `fork_choice` locks simultaneously.
## Breaking Changes
### The `state` (root) field in the `finalized_checkpoint` SSE event
Consider the scenario where epoch `n` is just finalized, but `start_slot(n)` is skipped. There are two state roots we might in the `finalized_checkpoint` SSE event:
1. The state root of the finalized block, which is `get_block(finalized_checkpoint.root).state_root`.
4. The state root at slot of `start_slot(n)`, which would be the state from (1), but "skipped forward" through any skip slots.
Previously, Lighthouse would choose (2). However, we can see that when [Teku generates that event](de2b2801c8/data/beaconrestapi/src/main/java/tech/pegasys/teku/beaconrestapi/handlers/v1/events/EventSubscriptionManager.java (L171-L182)) it uses [`getStateRootFromBlockRoot`](de2b2801c8/data/provider/src/main/java/tech/pegasys/teku/api/ChainDataProvider.java (L336-L341)) which uses (1).
I have switched Lighthouse from (2) to (1). I think it's a somewhat arbitrary choice between the two, where (1) is easier to compute and is consistent with Teku.
## Notes for Reviewers
I've renamed `BeaconChain::fork_choice` to `BeaconChain::recompute_head`. Doing this helped ensure I broke all previous uses of fork choice and I also find it more descriptive. It describes an action and can't be confused with trying to get a reference to the `ForkChoice` struct.
I've changed the ordering of SSE events when a block is received. It used to be `[block, finalized, head]` and now it's `[block, head, finalized]`. It was easier this way and I don't think we were making any promises about SSE event ordering so it's not "breaking".
I've made it so fork choice will run when it's first constructed. I did this because I wanted to have a cached version of the last call to `get_head`. Ensuring `get_head` has been run *at least once* means that the cached values doesn't need to wrapped in an `Option`. This was fairly simple, it just involved passing a `slot` to the constructor so it knows *when* it's being run. When loading a fork choice from the store and a slot clock isn't handy I've just used the `slot` that was saved in the `fork_choice_store`. That seems like it would be a faithful representation of the slot when we saved it.
I added the `genesis_time: u64` to the `BeaconChain`. It's small, constant and nice to have around.
Since we're using FC for the fin/just checkpoints, we no longer get the `0x00..00` roots at genesis. You can see I had to remove a work-around in `ef-tests` here: b56be3bc2. I can't find any reason why this would be an issue, if anything I think it'll be better since the genesis-alias has caught us out a few times (0x00..00 isn't actually a real root). Edit: I did find a case where the `network` expected the 0x00..00 alias and patched it here: 3f26ac3e2.
You'll notice a lot of changes in tests. Generally, tests should be functionally equivalent. Here are the things creating the most diff-noise in tests:
- Changing tests to be `tokio::async` tests.
- Adding `.await` to fork choice, block processing and block production functions.
- Refactor of the `canonical_head` "API" provided by the `BeaconChain`. E.g., `chain.canonical_head.cached_head()` instead of `chain.canonical_head.read()`.
- Wrapping `SignedBeaconBlock` in an `Arc`.
- In the `beacon_chain/tests/block_verification`, we can't use the `lazy_static` `CHAIN_SEGMENT` variable anymore since it's generated with an async function. We just generate it in each test, not so efficient but hopefully insignificant.
I had to disable `rayon` concurrent tests in the `fork_choice` tests. This is because the use of `rayon` and `block_on` was causing a panic.
Co-authored-by: Mac L <mjladson@pm.me>
## Issue Addressed
NA
## Proposed Changes
- Uses a `Vec` in `SingleEpochParticipationCache` rather than `HashMap` to speed up processing times at the cost of memory usage.
- Cache the result of `integer_sqrt` rather than recomputing for each validator.
- Cache `state.previous_epoch` rather than recomputing it for each validator.
### Benchmarks
Benchmarks on a recent mainnet state using #3252 to get timing.
#### Without this PR
```
lcli skip-slots --state-path /tmp/state-0x3cdc.ssz --partial-state-advance --slots 32 --state-root 0x3cdc33cd02713d8d6cc33a6dbe2d3a5bf9af1d357de0d175a403496486ff845e --runs 10
[2022-06-09T08:21:02Z INFO lcli::skip_slots] Using mainnet spec
[2022-06-09T08:21:02Z INFO lcli::skip_slots] Advancing 32 slots
[2022-06-09T08:21:02Z INFO lcli::skip_slots] Doing 10 runs
[2022-06-09T08:21:02Z INFO lcli::skip_slots] State path: "/tmp/state-0x3cdc.ssz"
SSZ decoding /tmp/state-0x3cdc.ssz: 43ms
[2022-06-09T08:21:03Z INFO lcli::skip_slots] Run 0: 245.718794ms
[2022-06-09T08:21:03Z INFO lcli::skip_slots] Run 1: 245.364782ms
[2022-06-09T08:21:03Z INFO lcli::skip_slots] Run 2: 255.866179ms
[2022-06-09T08:21:04Z INFO lcli::skip_slots] Run 3: 243.838909ms
[2022-06-09T08:21:04Z INFO lcli::skip_slots] Run 4: 250.431425ms
[2022-06-09T08:21:04Z INFO lcli::skip_slots] Run 5: 248.68765ms
[2022-06-09T08:21:04Z INFO lcli::skip_slots] Run 6: 262.051113ms
[2022-06-09T08:21:05Z INFO lcli::skip_slots] Run 7: 264.293967ms
[2022-06-09T08:21:05Z INFO lcli::skip_slots] Run 8: 293.202007ms
[2022-06-09T08:21:05Z INFO lcli::skip_slots] Run 9: 264.552017ms
```
#### With this PR:
```
lcli skip-slots --state-path /tmp/state-0x3cdc.ssz --partial-state-advance --slots 32 --state-root 0x3cdc33cd02713d8d6cc33a6dbe2d3a5bf9af1d357de0d175a403496486ff845e --runs 10
[2022-06-09T08:57:59Z INFO lcli::skip_slots] Run 0: 73.898678ms
[2022-06-09T08:57:59Z INFO lcli::skip_slots] Run 1: 75.536978ms
[2022-06-09T08:57:59Z INFO lcli::skip_slots] Run 2: 75.176104ms
[2022-06-09T08:57:59Z INFO lcli::skip_slots] Run 3: 76.460828ms
[2022-06-09T08:57:59Z INFO lcli::skip_slots] Run 4: 75.904195ms
[2022-06-09T08:58:00Z INFO lcli::skip_slots] Run 5: 75.53077ms
[2022-06-09T08:58:00Z INFO lcli::skip_slots] Run 6: 74.745572ms
[2022-06-09T08:58:00Z INFO lcli::skip_slots] Run 7: 75.823489ms
[2022-06-09T08:58:00Z INFO lcli::skip_slots] Run 8: 74.892055ms
[2022-06-09T08:58:00Z INFO lcli::skip_slots] Run 9: 76.333569ms
```
## Additional Info
NA
## Proposed Changes
Remove support for DB migrations that support upgrading from schema's below version 5. This is mostly for cosmetic/code quality reasons as in most circumstances upgrading from versions of Lighthouse this old will almost always require a re-sync.
## Additional Info
The minimum supported database schema is now version 5.
## Proposed Changes
I did some gardening 🌳 in our dependency tree:
- Remove duplicate versions of `warp` (git vs patch)
- Remove duplicate versions of lots of small deps: `cpufeatures`, `ethabi`, `ethereum-types`, `bitvec`, `nix`, `libsecp256k1`.
- Update MDBX (should resolve#3028). I tested and Lighthouse compiles on Windows 11 now.
- Restore `psutil` back to upstream
- Make some progress updating everything to rand 0.8. There are a few crates stuck on 0.7.
Hopefully this puts us on a better footing for future `cargo audit` issues, and improves compile times slightly.
## Additional Info
Some crates are held back by issues with `zeroize`. libp2p-noise depends on [`chacha20poly1305`](https://crates.io/crates/chacha20poly1305) which depends on zeroize < v1.5, and we can only have one version of zeroize because it's post 1.0 (see https://github.com/rust-lang/cargo/issues/6584). The latest version of `zeroize` is v1.5.4, which is used by the new versions of many other crates (e.g. `num-bigint-dig`). Once a new version of chacha20poly1305 is released we can update libp2p-noise and upgrade everything to the latest `zeroize` version.
I've also opened a PR to `blst` related to zeroize: https://github.com/supranational/blst/pull/111
## Proposed Changes
Lots of lint updates related to `flat_map`, `unwrap_or_else` and string patterns. I did a little more creative refactoring in the op pool, but otherwise followed Clippy's suggestions.
## Additional Info
We need this PR to unblock CI.
## 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
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>
## 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.
