Use x.rnd properly as the _previous_ round.

config/consensus.go

@@ -606,7 +606,7 @@ type ProposerPayoutRules struct {
 //
 //	BaseAmount: 0, DecayInterval: XXX
 //
-// by using a zero baseAmount, the amount not affected.
+// by using a zero baseAmount, the amount is not affected.
 // For a bigger change, we'd use a plan like:
 //
 //	BaseRound:  <FUTURE round>, BaseAmount: <new amount>, DecayInterval: <new>

ledger/eval/eval.go

@@ -207,14 +207,16 @@ func (x *roundCowBase) lookup(addr basics.Address) (ledgercore.AccountData, erro
 }
 
 // balanceRound reproduces the way that the agreement package finds the round to
-// consider for online accounts.
+// consider for online accounts. It returns the round that would be considered
+// while voting on the current round (which is x.rnd+1).
 func (x *roundCowBase) balanceRound() (basics.Round, error) {
-	phdr, err := x.BlockHdr(agreement.ParamsRound(x.rnd))
+	current := x.rnd + 1
+	phdr, err := x.BlockHdr(agreement.ParamsRound(current))
 	if err != nil {
 		return 0, err
 	}
 	agreementParams := config.Consensus[phdr.CurrentProtocol]
-	return agreement.BalanceRound(x.rnd, agreementParams), nil
+	return agreement.BalanceRound(current, agreementParams), nil
 }
 
 // lookupAgreement returns the online accountdata for the provided account address. It uses an internal cache
@@ -248,7 +250,7 @@ func (x *roundCowBase) onlineStake() (basics.MicroAlgos, error) {
 	if err != nil {
 		return basics.MicroAlgos{}, err
 	}
-	total, err := x.l.OnlineCirculation(brnd, x.rnd)
+	total, err := x.l.OnlineCirculation(brnd, x.rnd+1) // x.rnd+1 is round being built
 	if err != nil {
 		return basics.MicroAlgos{}, err
 	}