properly construct attestation data for selected slot

beacon_chain/attestation_aggregation.nim

@@ -5,15 +5,9 @@
 #   * Apache v2 license (license terms in the root directory or at http://www.apache.org/licenses/LICENSE-2.0).
 # at your option. This file may not be copied, modified, or distributed except according to those terms.
 
-# Mostly TODOs at this point, but basically, called every 1/3 + expected
-# network + attestation pool lag to collect attestations, if one wants a
-# maximally updated pool (but could also just only aggregate to previous
-# slots, safer probably), check for some fixed slot offset to past for a
-# locally attached validator (externally-to-this-module supplied), run a
-# set of supplied algorithms (already implemented) to check if that is a
-# matching pair. Aggregation itself's already implemented in attestation
-# pool, so this is mostly (a) selection of when to aggregate, (b) change
-# of validation, (c) and specific sending deadlines with slots.
+# Have an an aggregated aggregation ready for broadcast at
+# SECONDS_PER_SLOT * 2 / 3, i.e. 2/3 through relevant slot
+# intervals.
 #
 # The other part is arguably part of attestation pool -- the validation's
 # something that should be happing on receipt, not aggregation per se. In
@@ -23,23 +17,21 @@
 # already done.
 #
 # Finally, some of the filtering's libp2p stuff. Consistency checks between
-# topic/message types and GOSSIP_MAX_SIZE.
+# topic/message types and GOSSIP_MAX_SIZE -- mostly doesn't belong here, so
+# while TODO, isn't TODO for this module.
 
 import
   options,
-  ./spec/[datatypes, crypto, digest, helpers, validator],
+  ./spec/[beaconstate, datatypes, crypto, digest, helpers, validator],
   ./attestation_pool, ./beacon_node_types, ./ssz
 
 # TODO gossipsub validation lives somewhere, maybe here
 # TODO add tests, especially for validation
 # https://github.com/status-im/nim-beacon-chain/issues/122#issuecomment-562479965
-# it's conceptually separate, sort of, but depends on beaconstate, so isn't a
-# pure libp2p thing.
 
 const
   # https://github.com/ethereum/eth2.0-specs/blob/v0.9.2/specs/networking/p2p-interface.md#configuration
-  ATTESTATION_PROPAGATION_SLOT_RANGE* = 32
-  GOSSIP_MAX_SIZE = 1048576
+  ATTESTATION_PROPAGATION_SLOT_RANGE = 32
 
 # https://github.com/ethereum/eth2.0-specs/blob/v0.9.2/specs/validator/0_beacon-chain-validator.md#aggregation-selection
 func get_slot_signature(state: BeaconState, slot: Slot, privkey: ValidatorPrivKey):
@@ -77,18 +69,18 @@ proc aggregate_attestations*(
   if not is_aggregator(state, slot, index, slot_signature):
     return none(AggregateAndProof)
 
-  # https://github.com/ethereum/eth2.0-specs/blob/v0.9.2/specs/validator/0_beacon-chain-validator.md#construct-aggregate
-  let attestations = getAttestationsForBlock(pool, state, slot)
-
-  var correct_attestation_data: AttestationData
+  let attestation_data =
+    makeAttestationData(state, slot, index, get_block_root_at_slot(state, slot))
 
-  for attestation in attestations:
-    if attestation.data == correct_attestation_data:
+  # https://github.com/ethereum/eth2.0-specs/blob/v0.9.2/specs/validator/0_beacon-chain-validator.md#construct-aggregate
+  for attestation in getAttestationsForBlock(pool, state, slot):
+    if attestation.data == attestation_data:
+      # https://github.com/ethereum/eth2.0-specs/blob/v0.9.2/specs/validator/0_beacon-chain-validator.md#aggregateandproof
       return some(AggregateAndProof(
         aggregator_index: index,
         aggregate: attestation,
         selection_proof: slot_signature))
 
+  # TODO in catch-up mode, we could get here, so probably shouldn't assert
+  doAssert false
   none(AggregateAndProof)
-  # SECONDS_PER_SLOT / 3 in: initial aggregation TODO adjust this elsewhere
-  # SECONDS_PER_SLOT * 2 / 3