mirror of
https://github.com/ethereum/consensus-specs.git
synced 2026-02-15 19:35:19 -05:00
2e97af2627
While the light client sync protocol currently provides access to the latest `BeaconBlockHeader`, obtaining the matching execution data needs workarounds such as downloading the full block. Having ready access to the EL state root simplifies use cases that need a way to cross-check `eth_getProof` responses against LC data. Access to `block_hash` unlocks scenarios where a CL light client drives an EL without `engine_newPayload`. As of Altair, only the CL beacon block root is available, but the EL block hash is needed for engine API. Other fields in the `ExecutionPayloadHeader` such as `logs_bloom` may allow light client applications to monitor blocks for local interest, e.g. for transfers affecting a certain wallet. This enables to download only the few relevant blocks instead of every single one. A new `LightClientStore` is proposed into the Capella spec that may be used to sync LC data that includes execution data. Existing pre-Capella LC data will remain as is, but can be locally upgraded before feeding it into the new `LightClientStore` so that light clients do not need to run a potentially expensive fork transition at a specific time. This enables the `LightClientStore` to be upgraded at a use case dependent timing at any time before Capella hits. Smart contract and embedded deployments benefit from reduced code size and do not need synchronization with the beacon chain clock to perform the Capella fork.
92 lines
3.5 KiB
Markdown
92 lines
3.5 KiB
Markdown
# Light client sync tests
|
|
|
|
This series of tests provides reference test vectors for validating that a light client implementing the sync protocol can sync to the latest block header.
|
|
|
|
## Test case format
|
|
|
|
### `meta.yaml`
|
|
|
|
```yaml
|
|
genesis_validators_root: Bytes32 -- string, hex encoded, with 0x prefix
|
|
trusted_block_root: Bytes32 -- string, hex encoded, with 0x prefix
|
|
bootstrap_fork_digest: string -- Encoded `ForkDigest`-context of `bootstrap`
|
|
store_fork_digest: string -- Encoded `ForkDigest`-context of `store` object being tested
|
|
```
|
|
|
|
### `bootstrap.ssz_snappy`
|
|
|
|
An SSZ-snappy encoded `bootstrap` object of type `LightClientBootstrap` to initialize a local `store` object of type `LightClientStore` with `store_fork_digest` using `initialize_light_client_store(trusted_block_rooot, bootstrap)`. The SSZ type can be determined from `bootstrap_fork_digest`.
|
|
|
|
If `store_fork_digest` differs from `bootstrap_fork_digest`, the `bootstrap` object may need upgrading before initializing the store.
|
|
|
|
### `steps.yaml`
|
|
|
|
The steps to execute in sequence.
|
|
|
|
#### Checks to run after each step
|
|
|
|
Each step includes checks to verify the expected impact on the `store` object.
|
|
|
|
```yaml
|
|
finalized_header: {
|
|
slot: int, -- Integer value from get_lc_beacon_slot(store.finalized_header)
|
|
beacon_root: string, -- Encoded 32-byte value from get_lc_beacon_root(store.finalized_header)
|
|
execution_root: string, -- From Capella onward; get_lc_execution_root(store.finalized_header)
|
|
}
|
|
optimistic_header: {
|
|
slot: int, -- Integer value from get_lc_beacon_slot(store.optimistic_header)
|
|
beacon_root: string, -- Encoded 32-byte value from get_lc_beacon_root(store.optimistic_header)
|
|
execution_root: string, -- From Capella onward; get_lc_execution_root(store.optimistic_header)
|
|
}
|
|
```
|
|
|
|
#### `force_update` execution step
|
|
|
|
The function `process_light_client_store_force_update(store, current_slot)`
|
|
should be executed with the specified parameters:
|
|
|
|
```yaml
|
|
{
|
|
current_slot: int -- integer, decimal
|
|
checks: {<store_attibute>: value} -- the assertions.
|
|
}
|
|
```
|
|
|
|
After this step, the `store` object may have been updated.
|
|
|
|
#### `process_update` execution step
|
|
|
|
The function `process_light_client_update(store, update, current_slot, genesis_validators_root)` should be executed with the specified parameters:
|
|
|
|
```yaml
|
|
{
|
|
update_fork_digest: string -- Encoded `ForkDigest`-context of `update`
|
|
update: string -- name of the `*.ssz_snappy` file to load
|
|
as a `LightClientUpdate` object
|
|
current_slot: int -- integer, decimal
|
|
checks: {<store_attibute>: value} -- the assertions.
|
|
}
|
|
```
|
|
|
|
If `store_fork_digest` differs from `update_fork_digest`, the `update` object may need upgrading before initializing the store.
|
|
|
|
After this step, the `store` object may have been updated.
|
|
|
|
#### `process_upgrade_store`
|
|
|
|
The `store` should be upgraded to reflect the new `store_fork_digest`:
|
|
|
|
```yaml
|
|
{
|
|
store_fork_digest: string -- Encoded `ForkDigest`-context of `store`
|
|
checks: {<store_attibute>: value} -- the assertions.
|
|
}
|
|
```
|
|
|
|
After this step, the `store` object may have been updated.
|
|
|
|
|
|
## Condition
|
|
|
|
A test-runner should initialize a local `LightClientStore` using the provided `bootstrap` object. It should then proceed to execute all the test steps in sequence. After each step, it should verify that the resulting `store` verifies against the provided `checks`.
|