Fix unknown fields should be ignored when parsing liveness responses. (#5418)

beacon_chain/spec/eth2_apis/eth2_rest_serialization.nim

@@ -940,6 +940,9 @@ template unrecognizedFieldWarning =
   trace "JSON field not recognized by the current version of Nimbus. Consider upgrading",
         fieldName, typeName = typetraits.name(typeof value)
 
+template unrecognizedFieldIgnore =
+  discard readValue(reader, JsonString)
+
 ## ForkedBeaconBlock
 template prepareForkedBlockReading(
     reader: var JsonReader[RestJson],
@@ -2767,7 +2770,7 @@ proc readValue*(reader: var JsonReader[RestJson],
           "Multiple `active` fields found", "RestActivityItem")
       active = some(reader.readValue(bool))
     else:
-      discard
+      unrecognizedFieldIgnore()
 
   if index.isNone():
     reader.raiseUnexpectedValue("Missing or empty `index` value")
@@ -2807,7 +2810,7 @@ proc readValue*(reader: var JsonReader[RestJson],
           "Multiple `is_live` fields found", "RestLivenessItem")
       isLive = some(reader.readValue(bool))
     else:
-      discard
+      unrecognizedFieldIgnore()
 
   if index.isNone():
     reader.raiseUnexpectedValue("Missing or empty `index` value")
@@ -2935,8 +2938,7 @@ proc readValue*(reader: var JsonReader[RestJson],
                                     "RestErrorMessage")
       stacktraces = some(reader.readValue(seq[string]))
     else:
-      # We ignore all additional fields.
-      discard reader.readValue(JsonString)
+      unrecognizedFieldIgnore()
 
   if code.isNone():
     reader.raiseUnexpectedValue("Missing or invalid `code` value")

tests/test_validator_client.nim

@@ -376,3 +376,15 @@ suite "Validator Client test suite":
       check:
         res.isOk()
         res.get().data == expect
+
+    let vector = stringToBytes(
+      "{\"data\":[{\"index\":\"100000\",\"epoch\":\"202919\",\"is_live\":true}]}")
+
+    let contentType = getContentType("application/json").tryGet()
+    let res = decodeBytes(
+      GetValidatorsLivenessResponse, vector, Opt.some(contentType))
+    check:
+      res.isOk()
+      len(res.get().data) == 1
+      res.get().data[0].index == 100000
+      res.get().data[0].is_live == true