support EIP4844 LC data format (#4520)

Implements the proposed light client data format for EIP4844:
- https://github.com/ethereum/consensus-specs/pull/3151

ConsensusSpecPreset-mainnet.md

@@ -2023,6 +2023,14 @@ OK: 1/1 Fail: 0/1 Skip: 0/1
 +   Testing    Withdrawal                                                                    OK
 ```
 OK: 48/48 Fail: 0/48 Skip: 0/48
+## EF - EIP4844 - Unittests - Light client - Sync protocol [Preset: mainnet]
+```diff
++ process_light_client_update_finality_updated                                               OK
++ process_light_client_update_timeout                                                        OK
++ test_process_light_client_update_at_period_boundary                                        OK
++ test_process_light_client_update_not_timeout                                               OK
+```
+OK: 4/4 Fail: 0/4 Skip: 0/4
 ## EF - Phase 0 - Epoch Processing - Effective balance updates [Preset: mainnet]
 ```diff
 + Effective balance updates - effective_balance_hysteresis [Preset: mainnet]                 OK
@@ -2588,4 +2596,4 @@ OK: 63/63 Fail: 0/63 Skip: 0/63
 OK: 100/100 Fail: 0/100 Skip: 0/100
 
 ---TOTAL---
-OK: 2289/2298 Fail: 0/2298 Skip: 9/2298
+OK: 2293/2302 Fail: 0/2302 Skip: 9/2302

ConsensusSpecPreset-minimal.md

@@ -2187,6 +2187,14 @@ OK: 5/5 Fail: 0/5 Skip: 0/5
 +   Testing    Withdrawal                                                                    OK
 ```
 OK: 48/48 Fail: 0/48 Skip: 0/48
+## EF - EIP4844 - Unittests - Light client - Sync protocol [Preset: minimal]
+```diff
++ process_light_client_update_finality_updated                                               OK
++ process_light_client_update_timeout                                                        OK
++ test_process_light_client_update_at_period_boundary                                        OK
++ test_process_light_client_update_not_timeout                                               OK
+```
+OK: 4/4 Fail: 0/4 Skip: 0/4
 ## EF - Phase 0 - Epoch Processing - Effective balance updates [Preset: minimal]
 ```diff
 + Effective balance updates - effective_balance_hysteresis [Preset: minimal]                 OK
@@ -2755,4 +2763,4 @@ OK: 68/68 Fail: 0/68 Skip: 0/68
 OK: 102/102 Fail: 0/102 Skip: 0/102
 
 ---TOTAL---
-OK: 2440/2449 Fail: 0/2449 Skip: 9/2449
+OK: 2444/2453 Fail: 0/2453 Skip: 9/2453

beacon_chain/light_client.nim

@@ -347,10 +347,6 @@ proc installMessageValidators*(
 
   let forkDigests = lightClient.forkDigests
   for stateFork in BeaconStateFork:
-    if stateFork >= BeaconStateFork.EIP4844:
-      # Format is still in development, do not use Gossip at this time.
-      continue
-
     withLcDataFork(lcDataForkAtStateFork(stateFork)):
       when lcDataFork > LightClientDataFork.None:
         let
@@ -420,9 +416,6 @@ proc updateGossipStatus*(
 
   for gossipFork in oldGossipForks:
     if gossipFork >= BeaconStateFork.Altair:
-      if gossipFork >= BeaconStateFork.EIP4844:
-        # Format is still in development, do not use Gossip at this time.
-        continue
       let forkDigest = lightClient.forkDigests[].atStateFork(gossipFork)
       lightClient.network.unsubscribe(
         getLightClientFinalityUpdateTopic(forkDigest))
@@ -431,9 +424,6 @@ proc updateGossipStatus*(
 
   for gossipFork in newGossipForks:
     if gossipFork >= BeaconStateFork.Altair:
-      if gossipFork >= BeaconStateFork.EIP4844:
-        # Format is still in development, do not use Gossip at this time.
-        continue
       let forkDigest = lightClient.forkDigests[].atStateFork(gossipFork)
       lightClient.network.subscribe(
         getLightClientFinalityUpdateTopic(forkDigest),

beacon_chain/nimbus_beacon_node.nim

@@ -1430,7 +1430,7 @@ proc installMessageValidators(node: BeaconNode) =
   installPhase0Validators(forkDigests.altair)
   installPhase0Validators(forkDigests.bellatrix)
   installPhase0Validators(forkDigests.capella)
-  if node.dag.cfg.EIP4844_FORK_EPOCH != FAR_FUTURE_EPOCH:  
+  if node.dag.cfg.EIP4844_FORK_EPOCH != FAR_FUTURE_EPOCH:
     installPhase0Validators(forkDigests.eip4844)
 
   node.network.addValidator(
@@ -1466,8 +1466,14 @@ proc installMessageValidators(node: BeaconNode) =
   if node.dag.cfg.EIP4844_FORK_EPOCH != FAR_FUTURE_EPOCH:
     node.network.addValidator(
       getBeaconBlockAndBlobsSidecarTopic(forkDigests.eip4844),
-      proc (signedBlock: eip4844.SignedBeaconBlockAndBlobsSidecar): ValidationResult =
+      proc (
-        # TODO: take into account node.shouldSyncOptimistically(node.currentSlot)
+          signedBlock: eip4844.SignedBeaconBlockAndBlobsSidecar
+      ): ValidationResult =
+        if node.shouldSyncOptimistically(node.currentSlot):
+          toValidationResult(
+            node.optimisticProcessor.processSignedBeaconBlock(
+              signedBlock.beacon_block))
+        else:
           toValidationResult(node.processor[].processSignedBeaconBlock(
             MsgSource.gossip, signedBlock)))
 

beacon_chain/nimbus_light_client.nim

@@ -13,7 +13,7 @@ import
   ./gossip_processing/optimistic_processor,
   ./networking/topic_params,
   ./spec/beaconstate,
-  ./spec/datatypes/[phase0, altair, bellatrix, capella],
+  ./spec/datatypes/[phase0, altair, bellatrix, capella, eip4844],
   "."/[filepath, light_client, light_client_db, nimbus_binary_common, version]
 
 from ./consensus_object_pools/consensus_manager import runForkchoiceUpdated
@@ -156,6 +156,14 @@ programMain:
     proc (signedBlock: capella.SignedBeaconBlock): ValidationResult =
       toValidationResult(
         optimisticProcessor.processSignedBeaconBlock(signedBlock)))
+  network.addValidator(
+    getBeaconBlockAndBlobsSidecarTopic(forkDigests.eip4844),
+    proc (
+        signedBlock: eip4844.SignedBeaconBlockAndBlobsSidecar
+    ): ValidationResult =
+      toValidationResult(
+        optimisticProcessor.processSignedBeaconBlock(
+          signedBlock.beacon_block)))
   lightClient.installMessageValidators()
   waitFor network.startListening()
   waitFor network.start()
@@ -252,16 +260,10 @@ programMain:
       oldGossipForks = currentGossipState - targetGossipState
 
     for gossipFork in oldGossipForks:
-      if gossipFork >= BeaconStateFork.EIP4844:
-        # Format is still in development, do not use Gossip at this time.
-        continue
       let forkDigest = forkDigests[].atStateFork(gossipFork)
       network.unsubscribe(getBeaconBlocksTopic(forkDigest))
 
     for gossipFork in newGossipForks:
-      if gossipFork >= BeaconStateFork.EIP4844:
-        # Format is still in development, do not use Gossip at this time.
-        continue
       let forkDigest = forkDigests[].atStateFork(gossipFork)
       network.subscribe(
         getBeaconBlocksTopic(forkDigest), blocksTopicParams,

beacon_chain/spec/datatypes/eip4844.nim

@@ -19,8 +19,10 @@ else:
   {.push raises: [].}
 
 import
-  stew/byteutils,
+  chronicles,
+  stew/[bitops2, byteutils],
   json_serialization,
+  ssz_serialization/[merkleization, proofs],
   ssz_serialization/types as sszTypes,
   ../digest,
   "."/[base, phase0, altair, bellatrix, capella]
@@ -108,6 +110,102 @@ type
   ExecutePayload* = proc(
     execution_payload: ExecutionPayload): bool {.gcsafe, raises: [Defect].}
 
+  # https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.1/specs/capella/light-client/sync-protocol.md#lightclientheader
+  LightClientHeader* = object
+    beacon*: BeaconBlockHeader
+      ## Beacon block header
+
+    execution*: ExecutionPayloadHeader
+      ## Execution payload header corresponding to `beacon.body_root` (from Capella onward)
+    execution_branch*: capella.ExecutionBranch
+
+  # https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.1/specs/altair/light-client/sync-protocol.md#lightclientbootstrap
+  LightClientBootstrap* = object
+    header*: LightClientHeader
+      ## Header matching the requested beacon block root
+
+    current_sync_committee*: SyncCommittee
+      ## Current sync committee corresponding to `header.beacon.state_root`
+    current_sync_committee_branch*: altair.CurrentSyncCommitteeBranch
+
+  # https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.1/specs/altair/light-client/sync-protocol.md#lightclientupdate
+  LightClientUpdate* = object
+    attested_header*: LightClientHeader
+      ## Header attested to by the sync committee
+
+    next_sync_committee*: SyncCommittee
+      ## Next sync committee corresponding to `attested_header.beacon.state_root`
+    next_sync_committee_branch*: altair.NextSyncCommitteeBranch
+
+    # Finalized header corresponding to `attested_header.beacon.state_root`
+    finalized_header*: LightClientHeader
+    finality_branch*: altair.FinalityBranch
+
+    sync_aggregate*: SyncAggregate
+      ## Sync committee aggregate signature
+    signature_slot*: Slot
+      ## Slot at which the aggregate signature was created (untrusted)
+
+  # https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.1/specs/altair/light-client/sync-protocol.md#lightclientfinalityupdate
+  LightClientFinalityUpdate* = object
+    # Header attested to by the sync committee
+    attested_header*: LightClientHeader
+
+    # Finalized header corresponding to `attested_header.beacon.state_root`
+    finalized_header*: LightClientHeader
+    finality_branch*: altair.FinalityBranch
+
+    # Sync committee aggregate signature
+    sync_aggregate*: SyncAggregate
+    # Slot at which the aggregate signature was created (untrusted)
+    signature_slot*: Slot
+
+  # https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.1/specs/altair/light-client/sync-protocol.md#lightclientoptimisticupdate
+  LightClientOptimisticUpdate* = object
+    # Header attested to by the sync committee
+    attested_header*: LightClientHeader
+
+    # Sync committee aggregate signature
+    sync_aggregate*: SyncAggregate
+    # Slot at which the aggregate signature was created (untrusted)
+    signature_slot*: Slot
+
+  SomeLightClientUpdateWithSyncCommittee* =
+    LightClientUpdate
+
+  SomeLightClientUpdateWithFinality* =
+    LightClientUpdate |
+    LightClientFinalityUpdate
+
+  SomeLightClientUpdate* =
+    LightClientUpdate |
+    LightClientFinalityUpdate |
+    LightClientOptimisticUpdate
+
+  SomeLightClientObject* =
+    LightClientBootstrap |
+    SomeLightClientUpdate
+
+  # https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.1/specs/altair/light-client/sync-protocol.md#lightclientstore
+  LightClientStore* = object
+    finalized_header*: LightClientHeader
+      ## Header that is finalized
+
+    current_sync_committee*: SyncCommittee
+      ## Sync committees corresponding to the finalized header
+    next_sync_committee*: SyncCommittee
+
+    best_valid_update*: Opt[LightClientUpdate]
+      ## Best available header to switch finalized head to if we see nothing else
+
+    optimistic_header*: LightClientHeader
+      ## Most recent available reasonably-safe header
+
+    previous_max_active_participants*: uint64
+      ## Max number of active participants in a sync committee (used to compute
+      ## safety threshold)
+    current_max_active_participants*: uint64
+
   # https://github.com/ethereum/consensus-specs/blob/v1.3.0-alpha.1/specs/capella/beacon-chain.md#beaconstate
   # changes indirectly via ExecutionPayloadHeader
   BeaconState* = object
@@ -403,6 +501,243 @@ func shortLog*(v: SomeSignedBeaconBlock): auto =
     blck: shortLog(v.message),
     signature: shortLog(v.signature)
   )
+
+# https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.1/specs/eip4844/light-client/sync-protocol.md#get_lc_execution_root
+func get_lc_execution_root*(
+    header: LightClientHeader, cfg: RuntimeConfig): Eth2Digest =
+  let epoch = header.beacon.slot.epoch
+
+  if epoch >= cfg.EIP4844_FORK_EPOCH:
+    return hash_tree_root(header.execution)
+
+  if epoch >= cfg.CAPELLA_FORK_EPOCH:
+    let execution_header = capella.ExecutionPayloadHeader(
+      parent_hash: header.execution.parent_hash,
+      fee_recipient: header.execution.fee_recipient,
+      state_root: header.execution.state_root,
+      receipts_root: header.execution.receipts_root,
+      logs_bloom: header.execution.logs_bloom,
+      prev_randao: header.execution.prev_randao,
+      block_number: header.execution.block_number,
+      gas_limit: header.execution.gas_limit,
+      gas_used: header.execution.gas_used,
+      timestamp: header.execution.timestamp,
+      extra_data: header.execution.extra_data,
+      base_fee_per_gas: header.execution.base_fee_per_gas,
+      block_hash: header.execution.block_hash,
+      transactions_root: header.execution.transactions_root,
+      withdrawals_root: header.execution.withdrawals_root)
+    return hash_tree_root(execution_header)
+
+  ZERO_HASH
+
+# https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.1/specs/eip4844/light-client/sync-protocol.md#is_valid_light_client_header
+func is_valid_light_client_header*(
+    header: LightClientHeader, cfg: RuntimeConfig): bool =
+  let epoch = header.beacon.slot.epoch
+
+  if epoch < cfg.EIP4844_FORK_EPOCH:
+    if header.execution.excess_data_gas != 0.u256:
+      return false
+
+  if epoch < cfg.CAPELLA_FORK_EPOCH:
+    return
+      header.execution == default(ExecutionPayloadHeader) and
+      header.execution_branch == default(ExecutionBranch)
+
+  is_valid_merkle_branch(
+    get_lc_execution_root(header, cfg),
+    header.execution_branch,
+    log2trunc(EXECUTION_PAYLOAD_INDEX),
+    get_subtree_index(EXECUTION_PAYLOAD_INDEX),
+    header.beacon.body_root)
+
+# https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.1/specs/eip4844/light-client/fork.md#upgrade_lc_header_to_eip4844
+func upgrade_lc_header_to_eip4844*(
+    pre: capella.LightClientHeader): LightClientHeader =
+  LightClientHeader(
+    beacon: pre.beacon,
+    execution: ExecutionPayloadHeader(
+        parent_hash: pre.execution.parent_hash,
+        fee_recipient: pre.execution.fee_recipient,
+        state_root: pre.execution.state_root,
+        receipts_root: pre.execution.receipts_root,
+        logs_bloom: pre.execution.logs_bloom,
+        prev_randao: pre.execution.prev_randao,
+        block_number: pre.execution.block_number,
+        gas_limit: pre.execution.gas_limit,
+        gas_used: pre.execution.gas_used,
+        timestamp: pre.execution.timestamp,
+        extra_data: pre.execution.extra_data,
+        base_fee_per_gas: pre.execution.base_fee_per_gas,
+        block_hash: pre.execution.block_hash,
+        transactions_root: pre.execution.transactions_root,
+        withdrawals_root: pre.execution.withdrawals_root),
+    execution_branch: pre.execution_branch)
+
+# https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.1/specs/eip4844/light-client/fork.md#upgrade_lc_bootstrap_to_eip4844
+func upgrade_lc_bootstrap_to_eip4844*(
+    pre: capella.LightClientBootstrap): LightClientBootstrap =
+  LightClientBootstrap(
+    header: upgrade_lc_header_to_eip4844(pre.header),
+    current_sync_committee: pre.current_sync_committee,
+    current_sync_committee_branch: pre.current_sync_committee_branch)
+
+# https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.1/specs/eip4844/light-client/fork.md#upgrade_lc_update_to_eip4844
+func upgrade_lc_update_to_eip4844*(
+    pre: capella.LightClientUpdate): LightClientUpdate =
+  LightClientUpdate(
+    attested_header: upgrade_lc_header_to_eip4844(pre.attested_header),
+    next_sync_committee: pre.next_sync_committee,
+    next_sync_committee_branch: pre.next_sync_committee_branch,
+    finalized_header: upgrade_lc_header_to_eip4844(pre.finalized_header),
+    finality_branch: pre.finality_branch,
+    sync_aggregate: pre.sync_aggregate,
+    signature_slot: pre.signature_slot)
+
+# https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.1/specs/eip4844/light-client/fork.md#upgrade_lc_finality_update_to_eip4844
+func upgrade_lc_finality_update_to_eip4844*(
+    pre: capella.LightClientFinalityUpdate): LightClientFinalityUpdate =
+  LightClientFinalityUpdate(
+    attested_header: upgrade_lc_header_to_eip4844(pre.attested_header),
+    finalized_header: upgrade_lc_header_to_eip4844(pre.finalized_header),
+    finality_branch: pre.finality_branch,
+    sync_aggregate: pre.sync_aggregate,
+    signature_slot: pre.signature_slot)
+
+# https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.1/specs/eip4844/light-client/fork.md#upgrade_lc_optimistic_update_to_eip4844
+func upgrade_lc_optimistic_update_to_eip4844*(
+    pre: capella.LightClientOptimisticUpdate): LightClientOptimisticUpdate =
+  LightClientOptimisticUpdate(
+    attested_header: upgrade_lc_header_to_eip4844(pre.attested_header),
+    sync_aggregate: pre.sync_aggregate,
+    signature_slot: pre.signature_slot)
+
+func shortLog*(v: LightClientHeader): auto =
+  (
+    beacon: shortLog(v.beacon),
+    execution: (
+      block_hash: v.execution.block_hash,
+      block_number: v.execution.block_number)
+  )
+
+func shortLog*(v: LightClientBootstrap): auto =
+  (
+    header: shortLog(v.header)
+  )
+
+func shortLog*(v: LightClientUpdate): auto =
+  (
+    attested: shortLog(v.attested_header),
+    has_next_sync_committee:
+      v.next_sync_committee != default(typeof(v.next_sync_committee)),
+    finalized: shortLog(v.finalized_header),
+    num_active_participants: v.sync_aggregate.num_active_participants,
+    signature_slot: v.signature_slot
+  )
+
+func shortLog*(v: LightClientFinalityUpdate): auto =
+  (
+    attested: shortLog(v.attested_header),
+    finalized: shortLog(v.finalized_header),
+    num_active_participants: v.sync_aggregate.num_active_participants,
+    signature_slot: v.signature_slot
+  )
+
+func shortLog*(v: LightClientOptimisticUpdate): auto =
+  (
+    attested: shortLog(v.attested_header),
+    num_active_participants: v.sync_aggregate.num_active_participants,
+    signature_slot: v.signature_slot,
+  )
+
+chronicles.formatIt LightClientBootstrap: shortLog(it)
+chronicles.formatIt LightClientUpdate: shortLog(it)
+chronicles.formatIt LightClientFinalityUpdate: shortLog(it)
+chronicles.formatIt LightClientOptimisticUpdate: shortLog(it)
+
+template toFull*(
+    update: SomeLightClientUpdate): LightClientUpdate =
+  when update is LightClientUpdate:
+    update
+  elif update is SomeLightClientUpdateWithFinality:
+    LightClientUpdate(
+      attested_header: update.attested_header,
+      finalized_header: update.finalized_header,
+      finality_branch: update.finality_branch,
+      sync_aggregate: update.sync_aggregate,
+      signature_slot: update.signature_slot)
+  else:
+    LightClientUpdate(
+      attested_header: update.attested_header,
+      sync_aggregate: update.sync_aggregate,
+      signature_slot: update.signature_slot)
+
+template toFinality*(
+    update: SomeLightClientUpdate): LightClientFinalityUpdate =
+  when update is LightClientFinalityUpdate:
+    update
+  elif update is SomeLightClientUpdateWithFinality:
+    LightClientFinalityUpdate(
+      attested_header: update.attested_header,
+      finalized_header: update.finalized_header,
+      finality_branch: update.finality_branch,
+      sync_aggregate: update.sync_aggregate,
+      signature_slot: update.signature_slot)
+  else:
+    LightClientFinalityUpdate(
+      attested_header: update.attested_header,
+      sync_aggregate: update.sync_aggregate,
+      signature_slot: update.signature_slot)
+
+template toOptimistic*(
+    update: SomeLightClientUpdate): LightClientOptimisticUpdate =
+  when update is LightClientOptimisticUpdate:
+    update
+  else:
+    LightClientOptimisticUpdate(
+      attested_header: update.attested_header,
+      sync_aggregate: update.sync_aggregate,
+      signature_slot: update.signature_slot)
+
+func matches*[A, B: SomeLightClientUpdate](a: A, b: B): bool =
+  if a.attested_header != b.attested_header:
+    return false
+  when a is SomeLightClientUpdateWithSyncCommittee and
+      b is SomeLightClientUpdateWithSyncCommittee:
+    if a.next_sync_committee != b.next_sync_committee:
+      return false
+    if a.next_sync_committee_branch != b.next_sync_committee_branch:
+      return false
+  when a is SomeLightClientUpdateWithFinality and
+      b is SomeLightClientUpdateWithFinality:
+    if a.finalized_header != b.finalized_header:
+      return false
+    if a.finality_branch != b.finality_branch:
+      return false
+  if a.sync_aggregate != b.sync_aggregate:
+    return false
+  if a.signature_slot != b.signature_slot:
+    return false
+  true
+
+# https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.1/specs/eip4844/light-client/fork.md#upgrade_lc_store_to_eip4844
+func upgrade_lc_store_to_eip4844*(
+    pre: capella.LightClientStore): LightClientStore =
+  let best_valid_update =
+    if pre.best_valid_update.isNone:
+      Opt.none(LightClientUpdate)
+    else:
+      Opt.some upgrade_lc_update_to_eip4844(pre.best_valid_update.get)
+  LightClientStore(
+    finalized_header: upgrade_lc_header_to_eip4844(pre.finalized_header),
+    current_sync_committee: pre.current_sync_committee,
+    next_sync_committee: pre.next_sync_committee,
+    best_valid_update: best_valid_update,
+    optimistic_header: upgrade_lc_header_to_eip4844(pre.optimistic_header),
+    previous_max_active_participants: pre.previous_max_active_participants,
+    current_max_active_participants: pre.current_max_active_participants)
+
 template asSigned*(
     x: SigVerifiedSignedBeaconBlock |
        MsgTrustedSignedBeaconBlock |

beacon_chain/spec/forks.nim

@@ -927,8 +927,10 @@ func nextForkEpochAtEpoch*(cfg: RuntimeConfig, epoch: Epoch): Epoch =
   of BeaconStateFork.Phase0:    cfg.ALTAIR_FORK_EPOCH
 
 func lcDataForkAtStateFork*(stateFork: BeaconStateFork): LightClientDataFork =
-  static: doAssert LightClientDataFork.high == LightClientDataFork.Capella
+  static: doAssert LightClientDataFork.high == LightClientDataFork.EIP4844
-  if stateFork >= BeaconStateFork.Capella:
+  if stateFork >= BeaconStateFork.EIP4844:
+    LightClientDataFork.EIP4844
+  elif stateFork >= BeaconStateFork.Capella:
     LightClientDataFork.Capella
   elif stateFork >= BeaconStateFork.Altair:
     LightClientDataFork.Altair

beacon_chain/spec/forks_light_client.nim

@@ -18,27 +18,33 @@ type
   LightClientDataFork* {.pure.} = enum  # Append only, used in DB data!
     None = 0,  # only use non-0 in DB to detect accidentally uninitialized data
     Altair = 1,
-    Capella = 2
+    Capella = 2,
+    EIP4844 = 3
 
   ForkyLightClientHeader* =
     altair.LightClientHeader |
-    capella.LightClientHeader
+    capella.LightClientHeader |
+    eip4844.LightClientHeader
 
   ForkyLightClientBootstrap* =
     altair.LightClientBootstrap |
-    capella.LightClientBootstrap
+    capella.LightClientBootstrap |
+    eip4844.LightClientBootstrap
 
   ForkyLightClientUpdate* =
     altair.LightClientUpdate |
-    capella.LightClientUpdate
+    capella.LightClientUpdate |
+    eip4844.LightClientUpdate
 
   ForkyLightClientFinalityUpdate* =
     altair.LightClientFinalityUpdate |
-    capella.LightClientFinalityUpdate
+    capella.LightClientFinalityUpdate |
+    eip4844.LightClientFinalityUpdate
 
   ForkyLightClientOptimisticUpdate* =
     altair.LightClientOptimisticUpdate |
-    capella.LightClientOptimisticUpdate
+    capella.LightClientOptimisticUpdate |
+    eip4844.LightClientOptimisticUpdate
 
   SomeForkyLightClientUpdateWithSyncCommittee* =
     ForkyLightClientUpdate
@@ -58,7 +64,8 @@ type
 
   ForkyLightClientStore* =
     altair.LightClientStore |
-    capella.LightClientStore
+    capella.LightClientStore |
+    eip4844.LightClientStore
 
   ForkedLightClientHeader* = object
     case kind*: LightClientDataFork
@@ -68,6 +75,8 @@ type
       altairData*: altair.LightClientHeader
     of LightClientDataFork.Capella:
       capellaData*: capella.LightClientHeader
+    of LightClientDataFork.EIP4844:
+      eip4844Data*: eip4844.LightClientHeader
 
   ForkedLightClientBootstrap* = object
     case kind*: LightClientDataFork
@@ -77,6 +86,8 @@ type
       altairData*: altair.LightClientBootstrap
     of LightClientDataFork.Capella:
       capellaData*: capella.LightClientBootstrap
+    of LightClientDataFork.EIP4844:
+      eip4844Data*: eip4844.LightClientBootstrap
 
   ForkedLightClientUpdate* = object
     case kind*: LightClientDataFork
@@ -86,6 +97,8 @@ type
       altairData*: altair.LightClientUpdate
     of LightClientDataFork.Capella:
       capellaData*: capella.LightClientUpdate
+    of LightClientDataFork.EIP4844:
+      eip4844Data*: eip4844.LightClientUpdate
 
   ForkedLightClientFinalityUpdate* = object
     case kind*: LightClientDataFork
@@ -95,6 +108,8 @@ type
       altairData*: altair.LightClientFinalityUpdate
     of LightClientDataFork.Capella:
       capellaData*: capella.LightClientFinalityUpdate
+    of LightClientDataFork.EIP4844:
+      eip4844Data*: eip4844.LightClientFinalityUpdate
 
   ForkedLightClientOptimisticUpdate* = object
     case kind*: LightClientDataFork
@@ -104,6 +119,8 @@ type
       altairData*: altair.LightClientOptimisticUpdate
     of LightClientDataFork.Capella:
       capellaData*: capella.LightClientOptimisticUpdate
+    of LightClientDataFork.EIP4844:
+      eip4844Data*: eip4844.LightClientOptimisticUpdate
 
   SomeForkedLightClientUpdateWithSyncCommittee* =
     ForkedLightClientUpdate
@@ -129,11 +146,15 @@ type
       altairData*: altair.LightClientStore
     of LightClientDataFork.Capella:
       capellaData*: capella.LightClientStore
+    of LightClientDataFork.EIP4844:
+      eip4844Data*: eip4844.LightClientStore
 
 func lcDataForkAtEpoch*(
     cfg: RuntimeConfig, epoch: Epoch): LightClientDataFork =
-  static: doAssert LightClientDataFork.high == LightClientDataFork.Capella
+  static: doAssert LightClientDataFork.high == LightClientDataFork.EIP4844
-  if epoch >= cfg.CAPELLA_FORK_EPOCH:
+  if epoch >= cfg.EIP4844_FORK_EPOCH:
+    LightClientDataFork.EIP4844
+  elif epoch >= cfg.CAPELLA_FORK_EPOCH:
     LightClientDataFork.Capella
   elif epoch >= cfg.ALTAIR_FORK_EPOCH:
     LightClientDataFork.Altair
@@ -160,8 +181,20 @@ template kind*(
       capella.LightClientStore]): LightClientDataFork =
   LightClientDataFork.Capella
 
+template kind*(
+    x: typedesc[ # `SomeLightClientObject` doesn't work here (Nim 1.6)
+      eip4844.LightClientHeader |
+      eip4844.LightClientBootstrap |
+      eip4844.LightClientUpdate |
+      eip4844.LightClientFinalityUpdate |
+      eip4844.LightClientOptimisticUpdate |
+      eip4844.LightClientStore]): LightClientDataFork =
+  LightClientDataFork.EIP4844
+
 template LightClientHeader*(kind: static LightClientDataFork): auto =
-  when kind == LightClientDataFork.Capella:
+  when kind == LightClientDataFork.EIP4844:
+    typedesc[eip4844.LightClientHeader]
+  elif kind == LightClientDataFork.Capella:
     typedesc[capella.LightClientHeader]
   elif kind == LightClientDataFork.Altair:
     typedesc[altair.LightClientHeader]
@@ -169,7 +202,9 @@ template LightClientHeader*(kind: static LightClientDataFork): auto =
     static: raiseAssert "Unreachable"
 
 template LightClientBootstrap*(kind: static LightClientDataFork): auto =
-  when kind == LightClientDataFork.Capella:
+  when kind == LightClientDataFork.EIP4844:
+    typedesc[eip4844.LightClientBootstrap]
+  elif kind == LightClientDataFork.Capella:
     typedesc[capella.LightClientBootstrap]
   elif kind == LightClientDataFork.Altair:
     typedesc[altair.LightClientBootstrap]
@@ -177,7 +212,9 @@ template LightClientBootstrap*(kind: static LightClientDataFork): auto =
     static: raiseAssert "Unreachable"
 
 template LightClientUpdate*(kind: static LightClientDataFork): auto =
-  when kind == LightClientDataFork.Capella:
+  when kind == LightClientDataFork.EIP4844:
+    typedesc[eip4844.LightClientUpdate]
+  elif kind == LightClientDataFork.Capella:
     typedesc[capella.LightClientUpdate]
   elif kind == LightClientDataFork.Altair:
     typedesc[altair.LightClientUpdate]
@@ -185,7 +222,9 @@ template LightClientUpdate*(kind: static LightClientDataFork): auto =
     static: raiseAssert "Unreachable"
 
 template LightClientFinalityUpdate*(kind: static LightClientDataFork): auto =
-  when kind == LightClientDataFork.Capella:
+  when kind == LightClientDataFork.EIP4844:
+    typedesc[eip4844.LightClientFinalityUpdate]
+  elif kind == LightClientDataFork.Capella:
     typedesc[capella.LightClientFinalityUpdate]
   elif kind == LightClientDataFork.Altair:
     typedesc[altair.LightClientFinalityUpdate]
@@ -193,7 +232,9 @@ template LightClientFinalityUpdate*(kind: static LightClientDataFork): auto =
     static: raiseAssert "Unreachable"
 
 template LightClientOptimisticUpdate*(kind: static LightClientDataFork): auto =
-  when kind == LightClientDataFork.Capella:
+  when kind == LightClientDataFork.EIP4844:
+    typedesc[eip4844.LightClientOptimisticUpdate]
+  elif kind == LightClientDataFork.Capella:
     typedesc[capella.LightClientOptimisticUpdate]
   elif kind == LightClientDataFork.Altair:
     typedesc[altair.LightClientOptimisticUpdate]
@@ -201,7 +242,9 @@ template LightClientOptimisticUpdate*(kind: static LightClientDataFork): auto =
     static: raiseAssert "Unreachable"
 
 template LightClientStore*(kind: static LightClientDataFork): auto =
-  when kind == LightClientDataFork.Capella:
+  when kind == LightClientDataFork.EIP4844:
+    typedesc[eip4844.LightClientStore]
+  elif kind == LightClientDataFork.Capella:
     typedesc[capella.LightClientStore]
   elif kind == LightClientDataFork.Altair:
     typedesc[altair.LightClientStore]
@@ -258,7 +301,10 @@ template Forked*(x: typedesc[ForkyLightClientStore]): auto =
 
 template withAll*(
     x: typedesc[LightClientDataFork], body: untyped): untyped =
-  static: doAssert LightClientDataFork.high == LightClientDataFork.Capella
+  static: doAssert LightClientDataFork.high == LightClientDataFork.EIP4844
+  block:
+    const lcDataFork {.inject, used.} = LightClientDataFork.EIP4844
+    body
   block:
     const lcDataFork {.inject, used.} = LightClientDataFork.Capella
     body
@@ -272,6 +318,9 @@ template withAll*(
 template withLcDataFork*(
     x: LightClientDataFork, body: untyped): untyped =
   case x
+  of LightClientDataFork.EIP4844:
+    const lcDataFork {.inject, used.} = LightClientDataFork.EIP4844
+    body
   of LightClientDataFork.Capella:
     const lcDataFork {.inject, used.} = LightClientDataFork.Capella
     body
@@ -285,6 +334,10 @@ template withLcDataFork*(
 template withForkyHeader*(
     x: ForkedLightClientHeader, body: untyped): untyped =
   case x.kind
+  of LightClientDataFork.EIP4844:
+    const lcDataFork {.inject, used.} = LightClientDataFork.EIP4844
+    template forkyHeader: untyped {.inject, used.} = x.eip4844Data
+    body
   of LightClientDataFork.Capella:
     const lcDataFork {.inject, used.} = LightClientDataFork.Capella
     template forkyHeader: untyped {.inject, used.} = x.capellaData
@@ -300,6 +353,10 @@ template withForkyHeader*(
 template withForkyBootstrap*(
     x: ForkedLightClientBootstrap, body: untyped): untyped =
   case x.kind
+  of LightClientDataFork.EIP4844:
+    const lcDataFork {.inject, used.} = LightClientDataFork.EIP4844
+    template forkyBootstrap: untyped {.inject, used.} = x.eip4844Data
+    body
   of LightClientDataFork.Capella:
     const lcDataFork {.inject, used.} = LightClientDataFork.Capella
     template forkyBootstrap: untyped {.inject, used.} = x.capellaData
@@ -315,6 +372,10 @@ template withForkyBootstrap*(
 template withForkyUpdate*(
     x: ForkedLightClientUpdate, body: untyped): untyped =
   case x.kind
+  of LightClientDataFork.EIP4844:
+    const lcDataFork {.inject, used.} = LightClientDataFork.EIP4844
+    template forkyUpdate: untyped {.inject, used.} = x.eip4844Data
+    body
   of LightClientDataFork.Capella:
     const lcDataFork {.inject, used.} = LightClientDataFork.Capella
     template forkyUpdate: untyped {.inject, used.} = x.capellaData
@@ -330,6 +391,10 @@ template withForkyUpdate*(
 template withForkyFinalityUpdate*(
     x: ForkedLightClientFinalityUpdate, body: untyped): untyped =
   case x.kind
+  of LightClientDataFork.EIP4844:
+    const lcDataFork {.inject, used.} = LightClientDataFork.EIP4844
+    template forkyFinalityUpdate: untyped {.inject, used.} = x.eip4844Data
+    body
   of LightClientDataFork.Capella:
     const lcDataFork {.inject, used.} = LightClientDataFork.Capella
     template forkyFinalityUpdate: untyped {.inject, used.} = x.capellaData
@@ -345,6 +410,10 @@ template withForkyFinalityUpdate*(
 template withForkyOptimisticUpdate*(
     x: ForkedLightClientOptimisticUpdate, body: untyped): untyped =
   case x.kind
+  of LightClientDataFork.EIP4844:
+    const lcDataFork {.inject, used.} = LightClientDataFork.EIP4844
+    template forkyOptimisticUpdate: untyped {.inject, used.} = x.eip4844Data
+    body
   of LightClientDataFork.Capella:
     const lcDataFork {.inject, used.} = LightClientDataFork.Capella
     template forkyOptimisticUpdate: untyped {.inject, used.} = x.capellaData
@@ -360,6 +429,10 @@ template withForkyOptimisticUpdate*(
 template withForkyObject*(
     x: SomeForkedLightClientObject, body: untyped): untyped =
   case x.kind
+  of LightClientDataFork.EIP4844:
+    const lcDataFork {.inject, used.} = LightClientDataFork.EIP4844
+    template forkyObject: untyped {.inject, used.} = x.eip4844Data
+    body
   of LightClientDataFork.Capella:
     const lcDataFork {.inject, used.} = LightClientDataFork.Capella
     template forkyObject: untyped {.inject, used.} = x.capellaData
@@ -375,6 +448,10 @@ template withForkyObject*(
 template withForkyStore*(
     x: ForkedLightClientStore, body: untyped): untyped =
   case x.kind
+  of LightClientDataFork.EIP4844:
+    const lcDataFork {.inject, used.} = LightClientDataFork.EIP4844
+    template forkyStore: untyped {.inject, used.} = x.eip4844Data
+    body
   of LightClientDataFork.Capella:
     const lcDataFork {.inject, used.} = LightClientDataFork.Capella
     template forkyStore: untyped {.inject, used.} = x.capellaData
@@ -444,7 +521,9 @@ template forky*(
       SomeForkedLightClientObject |
       ForkedLightClientStore,
     kind: static LightClientDataFork): untyped =
-  when kind == LightClientDataFork.Capella:
+  when kind == LightClientDataFork.EIP4844:
+    x.eip4844Data
+  elif kind == LightClientDataFork.Capella:
     x.capellaData
   elif kind == LightClientDataFork.Altair:
     x.altairData
@@ -475,7 +554,15 @@ func migrateToDataFork*(
           capellaData: upgrade_lc_header_to_capella(
             x.forky(LightClientDataFork.Altair)))
 
-    static: doAssert LightClientDataFork.high == LightClientDataFork.Capella
+    # Upgrade to EIP4844
+    when newKind >= LightClientDataFork.EIP4844:
+      if x.kind == LightClientDataFork.Capella:
+        x = ForkedLightClientHeader(
+          kind: LightClientDataFork.EIP4844,
+          eip4844Data: upgrade_lc_header_to_eip4844(
+            x.forky(LightClientDataFork.Capella)))
+
+    static: doAssert LightClientDataFork.high == LightClientDataFork.EIP4844
     doAssert x.kind == newKind
 
 func migrateToDataFork*(
@@ -502,7 +589,15 @@ func migrateToDataFork*(
           capellaData: upgrade_lc_bootstrap_to_capella(
             x.forky(LightClientDataFork.Altair)))
 
-    static: doAssert LightClientDataFork.high == LightClientDataFork.Capella
+    # Upgrade to EIP4844
+    when newKind >= LightClientDataFork.EIP4844:
+      if x.kind == LightClientDataFork.Capella:
+        x = ForkedLightClientBootstrap(
+          kind: LightClientDataFork.EIP4844,
+          eip4844Data: upgrade_lc_bootstrap_to_eip4844(
+            x.forky(LightClientDataFork.Capella)))
+
+    static: doAssert LightClientDataFork.high == LightClientDataFork.EIP4844
     doAssert x.kind == newKind
 
 func migrateToDataFork*(
@@ -529,7 +624,15 @@ func migrateToDataFork*(
           capellaData: upgrade_lc_update_to_capella(
             x.forky(LightClientDataFork.Altair)))
 
-    static: doAssert LightClientDataFork.high == LightClientDataFork.Capella
+    # Upgrade to EIP4844
+    when newKind >= LightClientDataFork.EIP4844:
+      if x.kind == LightClientDataFork.Capella:
+        x = ForkedLightClientUpdate(
+          kind: LightClientDataFork.EIP4844,
+          eip4844Data: upgrade_lc_update_to_eip4844(
+            x.forky(LightClientDataFork.Capella)))
+
+    static: doAssert LightClientDataFork.high == LightClientDataFork.EIP4844
     doAssert x.kind == newKind
 
 func migrateToDataFork*(
@@ -556,7 +659,15 @@ func migrateToDataFork*(
           capellaData: upgrade_lc_finality_update_to_capella(
             x.forky(LightClientDataFork.Altair)))
 
-    static: doAssert LightClientDataFork.high == LightClientDataFork.Capella
+    # Upgrade to EIP4844
+    when newKind >= LightClientDataFork.EIP4844:
+      if x.kind == LightClientDataFork.Capella:
+        x = ForkedLightClientFinalityUpdate(
+          kind: LightClientDataFork.EIP4844,
+          eip4844Data: upgrade_lc_finality_update_to_eip4844(
+            x.forky(LightClientDataFork.Capella)))
+
+    static: doAssert LightClientDataFork.high == LightClientDataFork.EIP4844
     doAssert x.kind == newKind
 
 func migrateToDataFork*(
@@ -583,7 +694,15 @@ func migrateToDataFork*(
           capellaData: upgrade_lc_optimistic_update_to_capella(
             x.forky(LightClientDataFork.Altair)))
 
-    static: doAssert LightClientDataFork.high == LightClientDataFork.Capella
+    # Upgrade to EIP4844
+    when newKind >= LightClientDataFork.EIP4844:
+      if x.kind == LightClientDataFork.Capella:
+        x = ForkedLightClientOptimisticUpdate(
+          kind: LightClientDataFork.EIP4844,
+          eip4844Data: upgrade_lc_optimistic_update_to_eip4844(
+            x.forky(LightClientDataFork.Capella)))
+
+    static: doAssert LightClientDataFork.high == LightClientDataFork.EIP4844
     doAssert x.kind == newKind
 
 func migrateToDataFork*(
@@ -610,7 +729,15 @@ func migrateToDataFork*(
           capellaData: upgrade_lc_store_to_capella(
             x.forky(LightClientDataFork.Altair)))
 
-    static: doAssert LightClientDataFork.high == LightClientDataFork.Capella
+    # Upgrade to EIP4844
+    when newKind >= LightClientDataFork.EIP4844:
+      if x.kind == LightClientDataFork.Capella:
+        x = ForkedLightClientStore(
+          kind: LightClientDataFork.EIP4844,
+          eip4844Data: upgrade_lc_store_to_eip4844(
+            x.forky(LightClientDataFork.Capella)))
+
+    static: doAssert LightClientDataFork.high == LightClientDataFork.EIP4844
     doAssert x.kind == newKind
 
 func migratingToDataFork*[
@@ -651,8 +778,7 @@ func toCapellaLightClientHeader(
 
 func toCapellaLightClientHeader(
     blck:  # `SomeSignedBeaconBlock` doesn't work here (Nim 1.6)
-      capella.SignedBeaconBlock | capella.TrustedSignedBeaconBlock |
+      capella.SignedBeaconBlock | capella.TrustedSignedBeaconBlock
-      eip4844.SignedBeaconBlock | eip4844.TrustedSignedBeaconBlock
 ): capella.LightClientHeader =
   template payload: untyped = blck.message.body.execution_payload
   capella.LightClientHeader(
@@ -676,6 +802,75 @@ func toCapellaLightClientHeader(
     execution_branch: blck.message.body.build_proof(
       capella.EXECUTION_PAYLOAD_INDEX).get)
 
+# https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.1/specs/eip4844/light-client/full-node.md#block_to_light_client_header
+func toEIP4844LightClientHeader(
+    blck:  # `SomeSignedBeaconBlock` doesn't work here (Nim 1.6)
+      phase0.SignedBeaconBlock | phase0.TrustedSignedBeaconBlock |
+      altair.SignedBeaconBlock | altair.TrustedSignedBeaconBlock |
+      bellatrix.SignedBeaconBlock | bellatrix.TrustedSignedBeaconBlock
+): eip4844.LightClientHeader =
+  # Note that during fork transitions, `finalized_header` may still
+  # point to earlier forks. While Bellatrix blocks also contain an
+  # `ExecutionPayload` (minus `withdrawals_root`), it was not included
+  # in the corresponding light client data. To ensure compatibility
+  # with legacy data going through `upgrade_lc_header_to_capella`,
+  # leave out execution data.
+  eip4844.LightClientHeader(
+    beacon: blck.message.toBeaconBlockHeader())
+
+func toEIP4844LightClientHeader(
+    blck:  # `SomeSignedBeaconBlock` doesn't work here (Nim 1.6)
+      capella.SignedBeaconBlock | capella.TrustedSignedBeaconBlock
+): eip4844.LightClientHeader =
+  template payload: untyped = blck.message.body.execution_payload
+  eip4844.LightClientHeader(
+    beacon: blck.message.toBeaconBlockHeader(),
+    execution: eip4844.ExecutionPayloadHeader(
+      parent_hash: payload.parent_hash,
+      fee_recipient: payload.fee_recipient,
+      state_root: payload.state_root,
+      receipts_root: payload.receipts_root,
+      logs_bloom: payload.logs_bloom,
+      prev_randao: payload.prev_randao,
+      block_number: payload.block_number,
+      gas_limit: payload.gas_limit,
+      gas_used: payload.gas_used,
+      timestamp: payload.timestamp,
+      extra_data: payload.extra_data,
+      base_fee_per_gas: payload.base_fee_per_gas,
+      block_hash: payload.block_hash,
+      transactions_root: hash_tree_root(payload.transactions),
+      withdrawals_root: hash_tree_root(payload.withdrawals)),
+    execution_branch: blck.message.body.build_proof(
+      capella.EXECUTION_PAYLOAD_INDEX).get)
+
+func toEIP4844LightClientHeader(
+    blck:  # `SomeSignedBeaconBlock` doesn't work here (Nim 1.6)
+      eip4844.SignedBeaconBlock | eip4844.TrustedSignedBeaconBlock
+): eip4844.LightClientHeader =
+  template payload: untyped = blck.message.body.execution_payload
+  eip4844.LightClientHeader(
+    beacon: blck.message.toBeaconBlockHeader(),
+    execution: eip4844.ExecutionPayloadHeader(
+      parent_hash: payload.parent_hash,
+      fee_recipient: payload.fee_recipient,
+      state_root: payload.state_root,
+      receipts_root: payload.receipts_root,
+      logs_bloom: payload.logs_bloom,
+      prev_randao: payload.prev_randao,
+      block_number: payload.block_number,
+      gas_limit: payload.gas_limit,
+      gas_used: payload.gas_used,
+      timestamp: payload.timestamp,
+      extra_data: payload.extra_data,
+      base_fee_per_gas: payload.base_fee_per_gas,
+      excess_data_gas: payload.excess_data_gas,
+      block_hash: payload.block_hash,
+      transactions_root: hash_tree_root(payload.transactions),
+      withdrawals_root: hash_tree_root(payload.withdrawals)),
+    execution_branch: blck.message.body.build_proof(
+      capella.EXECUTION_PAYLOAD_INDEX).get)
+
 func toLightClientHeader*(
     blck:  # `SomeSignedBeaconBlock` doesn't work here (Nim 1.6)
       phase0.SignedBeaconBlock | phase0.TrustedSignedBeaconBlock |
@@ -684,7 +879,9 @@ func toLightClientHeader*(
       capella.SignedBeaconBlock | capella.TrustedSignedBeaconBlock |
       eip4844.SignedBeaconBlock | eip4844.TrustedSignedBeaconBlock,
     kind: static LightClientDataFork): auto =
-  when kind == LightClientDataFork.Capella:
+  when kind == LightClientDataFork.EIP4844:
+    blck.toEIP4844LightClientHeader()
+  elif kind == LightClientDataFork.Capella:
     blck.toCapellaLightClientHeader()
   elif kind == LightClientDataFork.Altair:
     blck.toAltairLightClientHeader()

tests/consensus_spec/eip4844/test_fixture_ssz_consensus_objects.nim

@@ -126,15 +126,15 @@ suite "EF - EIP4844 - SSZ consensus objects " & preset():
           of "HistoricalSummary": checkSSZ(HistoricalSummary, path, hash)
           of "IndexedAttestation": checkSSZ(IndexedAttestation, path, hash)
           of "LightClientBootstrap":
-            discard  # checkSSZ(capella.LightClientBootstrap, path, hash)
+            discard  # checkSSZ(eip4844.LightClientBootstrap, path, hash)
           of "LightClientHeader":
-            discard  # checkSSZ(capella.LightClientHeader, path, hash)
+            discard  # checkSSZ(eip4844.LightClientHeader, path, hash)
           of "LightClientUpdate":
-            discard  # checkSSZ(capella.LightClientUpdate, path, hash)
+            discard  # checkSSZ(eip4844.LightClientUpdate, path, hash)
           of "LightClientFinalityUpdate":
-            discard  # checkSSZ(capella.LightClientFinalityUpdate, path, hash)
+            discard  # checkSSZ(eip4844.LightClientFinalityUpdate, path, hash)
           of "LightClientOptimisticUpdate":
-            discard  # checkSSZ(capella.LightClientOptimisticUpdate, path, hash)
+            discard  # checkSSZ(eip4844.LightClientOptimisticUpdate, path, hash)
           of "PendingAttestation": checkSSZ(PendingAttestation, path, hash)
           of "PowBlock": checkSSZ(PowBlock, path, hash)
           of "ProposerSlashing": checkSSZ(ProposerSlashing, path, hash)

tests/test_light_client_processor.nim

@@ -151,13 +151,8 @@ suite "Light client processor" & preset():
         applyPeriodWithSupermajority(period)
 
       # Reduce stack size by making this a `proc`
-      proc applyPeriodWithoutSupermajority(period: SyncCommitteePeriod) =
+      proc applyPeriodWithoutSupermajority(
-        let update = newClone(dag.getLightClientUpdateForPeriod(period))
+          period: SyncCommitteePeriod, update: ref ForkedLightClientUpdate) =
-        check update[].kind > LightClientDataFork.None
-        withForkyUpdate(update[]):
-          when lcDataFork > LightClientDataFork.None:
-            setTimeToSlot(forkyUpdate.signature_slot)
-
         for i in 0 ..< 2:
           res = processor[].storeObject(
             MsgSource.gossip, getBeaconTime(), update[])
@@ -198,7 +193,8 @@ suite "Light client processor" & preset():
                   forkyStore.best_valid_update.isSome
                   not forkyStore.best_valid_update.get.matches(forkyUpdate)
 
-          proc applyDuplicate() = # Reduce stack size by making this a `proc`
+          # Reduce stack size by making this a `proc`
+          proc applyDuplicate(update: ref ForkedLightClientUpdate) =
             res = processor[].storeObject(
               MsgSource.gossip, getBeaconTime(), update[])
             check update[].kind <= store[].kind
@@ -226,10 +222,10 @@ suite "Light client processor" & preset():
                     forkyStore.best_valid_update.isSome
                     not forkyStore.best_valid_update.get.matches(forkyUpdate)
 
-          applyDuplicate()
+          applyDuplicate(update)
           time += chronos.minutes(15)
           for _ in 0 ..< 150:
-            applyDuplicate()
+            applyDuplicate(update)
             time += chronos.seconds(5)
           time += chronos.minutes(15)
 
@@ -272,6 +268,16 @@ suite "Light client processor" & preset():
                   res.error == VerifierError.MissingParent
                   forkyStore.best_valid_update.isSome
                   not forkyStore.best_valid_update.get.matches(forkyUpdate)
+
+      for period in lastPeriodWithSupermajority + 1 .. highPeriod:
+        let update = newClone(dag.getLightClientUpdateForPeriod(period))
+        check update[].kind > LightClientDataFork.None
+        withForkyUpdate(update[]):
+          when lcDataFork > LightClientDataFork.None:
+            setTimeToSlot(forkyUpdate.signature_slot)
+
+        applyPeriodWithoutSupermajority(period, update)
+
         if finalizationMode == LightClientFinalizationMode.Optimistic:
           withForkyStore(store[]):
             when lcDataFork > LightClientDataFork.None:
@@ -287,9 +293,6 @@ suite "Light client processor" & preset():
               template forkyUpdate: untyped = upgraded[].forky(lcDataFork)
               check forkyStore.finalized_header != forkyUpdate.attested_header
 
-      for period in lastPeriodWithSupermajority + 1 .. highPeriod:
-        applyPeriodWithoutSupermajority(period)
-
       var oldFinalized {.noinit.}: ForkedLightClientHeader
       withForkyStore(store[]):
         when lcDataFork > LightClientDataFork.None: