code review

data/transactions/heartbeat.go

@@ -34,9 +34,9 @@ type HeartbeatTxnFields struct {
 	// HbProof is a signature using HeartbeatAddress's partkey, thereby showing it is online.
 	HbProof crypto.HeartbeatProof `codec:"hbprf"`
 
-	// HbSeed must be the block seed for the block before this transaction's
-	// firstValid. It is supplied in the transaction so that Proof can be
-	// checked at submit time without a ledger lookup, and must be checked at
-	// evaluation time for equality with the actual blockseed.
+	// HbSeed must be the block seed for the this transaction's firstValid
+	// block. It is supplied in the transaction so that Proof can be checked at
+	// submit time without a ledger lookup, and must be checked at evaluation
+	// time for equality with the actual blockseed.
 	HbSeed committee.Seed `codec:"hbsd"`
 }

ledger/apply/challenge.go

@@ -72,7 +72,7 @@ func FindChallenge(rules config.ProposerPayoutRules, current basics.Round, heade
 	}
 	challengeHdr, err := headers.BlockHdr(lastChallenge)
 	if err != nil {
-		panic(err)
+		return challenge{}
 	}
 	challengeProto := config.Consensus[challengeHdr.CurrentProtocol]
 	// challenge is not considered if rules have changed since that round

ledger/apply/heartbeat.go

@@ -62,7 +62,7 @@ func Heartbeat(hb transactions.HeartbeatTxnFields, header transactions.Header, b
 			return fmt.Errorf("%s heartbeat is not allowed when not IncentiveEligible %+v", kind, hb.HbAddress)
 		}
 		ch := FindChallenge(proto.Payouts, round, provider, ChRisky)
-		if ch.round == 0 {
+		if ch.IsZero() {
 			return fmt.Errorf("%s heartbeat for %s is not allowed with no challenge", kind, hb.HbAddress)
 		}
 		if !ch.Failed(hb.HbAddress, account.LastSeen()) {