Fix VC not properly handled getAggregatedAttestation's 404 error. (#6254)

* Fix VC not properly handled getAggregatedAttestation's 404 error.

* Update AllTests.

AllTests-mainnet.md

@@ -891,6 +891,7 @@ OK: 1/1 Fail: 0/1 Skip: 0/1
 + /eth/v1/validator/sync_committee_selections serialization/deserialization test             OK
 + bestSuccess() API timeout test                                                             OK
 + firstSuccessParallel() API timeout test                                                    OK
++ getAggregatedAttestationDataScore() default test                                           OK
 + getAggregatedAttestationDataScore() test vectors                                           OK
 + getAttestationDataScore() test vectors                                                     OK
 + getLiveness() response deserialization test                                                OK
@@ -899,7 +900,7 @@ OK: 1/1 Fail: 0/1 Skip: 0/1
 + getUniqueVotes() test vectors                                                              OK
 + normalizeUri() test vectors                                                                OK
 ```
-OK: 11/11 Fail: 0/11 Skip: 0/11
+OK: 12/12 Fail: 0/12 Skip: 0/12
 ## Validator change pool testing suite
 ```diff
 + addValidatorChangeMessage/getAttesterSlashingMessage                                       OK
@@ -1019,4 +1020,4 @@ OK: 2/2 Fail: 0/2 Skip: 0/2
 OK: 9/9 Fail: 0/9 Skip: 0/9
 
 ---TOTAL---
-OK: 684/689 Fail: 0/689 Skip: 5/689
+OK: 685/690 Fail: 0/690 Skip: 5/690

beacon_chain/spec/eth2_apis/rest_types.nim

@@ -45,6 +45,9 @@ const
 
 const
   preferSSZ* = "application/octet-stream,application/json;q=0.9"
+  LowestScoreAggregatedAttestation* =
+    phase0.Attestation(
+      aggregation_bits: CommitteeValidatorsBits(BitSeq.init(1)))
 
 static:
   doAssert(ClientMaximumValidatorIds <= ServerMaximumValidatorIds)
@@ -615,6 +618,10 @@ type
     fork_choice_nodes*: seq[RestNode]
     extra_data*: RestExtraData
 
+func isLowestScoreAggregatedAttestation*(a: phase0.Attestation): bool =
+  (a.data.slot == Slot(0)) and (a.data.index == 0'u64) and
+  (a.data.source.epoch == Epoch(0)) and (a.data.target.epoch == Epoch(0))
+
 func `==`*(a, b: RestValidatorIndex): bool =
   uint64(a) == uint64(b)
 

beacon_chain/validator_client/api.nim

@@ -1708,6 +1708,13 @@ proc getAggregatedAttestation*(
           handle400()
           ApiResponse[GetAggregatedAttestationResponse].err(
             ResponseInvalidError)
+        of 404:
+          # A 404 error must be returned if no attestation is available for the
+          # requested `attestation_data_root`. To address the issue #6184, we
+          # use empty GetAggregatedAttestationResponse.
+          ApiResponse[GetAggregatedAttestationResponse].ok(
+            GetAggregatedAttestationResponse(
+              data: LowestScoreAggregatedAttestation))
         of 500:
           handle500()
           ApiResponse[GetAggregatedAttestationResponse].err(

beacon_chain/validator_client/attestation_service.nim

@@ -296,6 +296,12 @@ proc produceAndPublishAggregates(service: AttestationServiceRef,
               err_name = exc.name, err_msg = exc.msg
         return
 
+    if isLowestScoreAggregatedAttestation(aggAttestation):
+      warn "Aggregated attestation with the root was not seen by the " &
+           "beacon node",
+           attestation_root = shortLog(attestationRoot)
+      return
+
     let pendingAggregates =
       block:
         var res: seq[Future[bool]]

tests/test_validator_client.nim

@@ -746,6 +746,15 @@ suite "Validator Client test suite":
         score = shortScore(getAggregatedAttestationDataScore(adata))
       check score == vector[1]
 
+  test "getAggregatedAttestationDataScore() default test":
+    let
+      adata = GetAggregatedAttestationResponse(
+        data: LowestScoreAggregatedAttestation)
+      score = shortScore(getAggregatedAttestationDataScore(adata))
+    check:
+      score == "0.0000"
+      isLowestScoreAggregatedAttestation(adata.data) == true
+
   test "getSyncCommitteeContributionDataScore() test vectors":
     for vector in ContributionDataVectors:
       let