Separate type for unaggregated network attestations

specs/electra/beacon-chain.md

@@ -30,6 +30,7 @@
     - [`WithdrawalRequest`](#withdrawalrequest)
     - [`ConsolidationRequest`](#consolidationrequest)
     - [`PendingConsolidation`](#pendingconsolidation)
+    - [`SingleAttestation`](#singleattestation)
   - [Modified Containers](#modified-containers)
     - [`AttesterSlashing`](#attesterslashing)
   - [Extended Containers](#extended-containers)
@@ -258,6 +259,17 @@ class PendingConsolidation(Container):
     target_index: ValidatorIndex
 ```
 
+
+#### `SingleAttestation`
+
+```python
+class SingleAttestation(Container):
+    committee_index: CommitteeIndex
+    attester_index: ValidatorIndex
+    data: AttestationData
+    signature: BLSSignature
+```
+
 ### Modified Containers
 
 #### `AttesterSlashing`
@@ -875,7 +887,7 @@ def process_pending_balance_deposits(state: BeaconState) -> None:
             if processed_amount + deposit.amount > available_for_processing:
                 break
             # Deposit fits in the churn, process it. Increase balance and consume churn.
-            else: 
+            else:
                 increase_balance(state, deposit.index, deposit.amount)
                 processed_amount += deposit.amount
         # Regardless of how the deposit was handled, we move on in the queue.

specs/electra/p2p-interface.md

@@ -54,9 +54,18 @@ The following validations are added:
 
 ##### `beacon_attestation_{subnet_id}`
 
-The following convenience variables are re-defined
-- `index = get_committee_indices(attestation.committee_bits)[0]`
+The topic is updated to propagate `SingleAttestation` objects.
+
+The following convenience variables are re-defined:
+- `index = attestation.committee_index`
 
 The following validations are added:
-* [REJECT] `len(committee_indices) == 1`, where `committee_indices = get_committee_indices(attestation)`.
-* [REJECT] `attestation.data.index == 0`
+- _[REJECT]_ `attestation.data.index == 0`
+- _[REJECT]_ The attester is a member of the committee -- i.e.
+  `atestation.attester_index in get_beacon_committee(state, attestation.data.slot, index)`.
+
+The following validations are removed:
+- _[REJECT]_ The attestation is unaggregated --
+  that is, it has exactly one participating validator (`len([bit for bit in aggregation_bits if bit]) == 1`, i.e. exactly 1 bit is set).
+- _[REJECT]_ The number of aggregation bits matches the committee size -- i.e.
+  `len(aggregation_bits) == len(get_beacon_committee(state, attestation.data.slot, index))`.