Fix calculation of GasReward in messagepool

chain/messagepool/selection.go

@@ -585,16 +585,18 @@ func (mp *MessagePool) getPendingMessages(curTs, ts *types.TipSet) (map[address.
 	return result, nil
 }
 
-func (mp *MessagePool) getGasReward(msg *types.SignedMessage, baseFee types.BigInt, ts *types.TipSet) *big.Int {
+func (*MessagePool) getGasReward(msg *types.SignedMessage, baseFee types.BigInt) *big.Int {
 	maxPremium := types.BigSub(msg.Message.GasFeeCap, baseFee)
-	if types.BigCmp(maxPremium, msg.Message.GasPremium) < 0 {
+
+	if types.BigCmp(maxPremium, msg.Message.GasPremium) > 0 {
 		maxPremium = msg.Message.GasPremium
 	}
+
 	gasReward := abig.Mul(maxPremium, types.NewInt(uint64(msg.Message.GasLimit)))
 	return gasReward.Int
 }
 
-func (mp *MessagePool) getGasPerf(gasReward *big.Int, gasLimit int64) float64 {
+func (*MessagePool) getGasPerf(gasReward *big.Int, gasLimit int64) float64 {
 	// gasPerf = gasReward * build.BlockGasLimit / gasLimit
 	a := new(big.Rat).SetInt(new(big.Int).Mul(gasReward, bigBlockGasLimit))
 	b := big.NewRat(1, gasLimit)
@@ -672,7 +674,7 @@ func (mp *MessagePool) createMessageChains(actor address.Address, mset map[uint6
 			balance = new(big.Int).Sub(balance, value)
 		}
 
-		gasReward := mp.getGasReward(m, baseFee, ts)
+		gasReward := mp.getGasReward(m, baseFee)
 		rewards = append(rewards, gasReward)
 	}
 
@@ -776,7 +778,7 @@ func (mc *msgChain) Before(other *msgChain) bool {
 func (mc *msgChain) Trim(gasLimit int64, mp *MessagePool, baseFee types.BigInt, ts *types.TipSet) {
 	i := len(mc.msgs) - 1
 	for i >= 0 && (mc.gasLimit > gasLimit || mc.gasPerf < 0) {
-		gasReward := mp.getGasReward(mc.msgs[i], baseFee, ts)
+		gasReward := mp.getGasReward(mc.msgs[i], baseFee)
 		mc.gasReward = new(big.Int).Sub(mc.gasReward, gasReward)
 		mc.gasLimit -= mc.msgs[i].Message.GasLimit
 		if mc.gasLimit > 0 {

chain/messagepool/selection_test.go

@@ -2,6 +2,7 @@ package messagepool
 
 import (
 	"context"
+	"fmt"
 	"math"
 	"math/big"
 	"math/rand"
@@ -1055,17 +1056,17 @@ func testCompetitiveMessageSelection(t *testing.T, rng *rand.Rand, getPremium fu
 
 		greedyReward := big.NewInt(0)
 		for _, m := range greedyMsgs {
-			greedyReward.Add(greedyReward, mp.getGasReward(m, baseFee, ts))
+			greedyReward.Add(greedyReward, mp.getGasReward(m, baseFee))
 		}
 
 		optReward := big.NewInt(0)
 		for _, m := range optMsgs {
-			optReward.Add(optReward, mp.getGasReward(m, baseFee, ts))
+			optReward.Add(optReward, mp.getGasReward(m, baseFee))
 		}
 
 		bestTqReward := big.NewInt(0)
 		for _, m := range bestMsgs {
-			bestTqReward.Add(bestTqReward, mp.getGasReward(m, baseFee, ts))
+			bestTqReward.Add(bestTqReward, mp.getGasReward(m, baseFee))
 		}
 
 		totalBestTQReward += float64(bestTqReward.Uint64())
@@ -1146,3 +1147,35 @@ func TestCompetitiveMessageSelectionZipf(t *testing.T) {
 	t.Logf("Average reward boost across all seeds: %f", rewardBoost)
 	t.Logf("Average reward of best ticket across all seeds: %f", tqReward)
 }
+
+func TestGasReward(t *testing.T) {
+	tests := []struct {
+		Premium   uint64
+		FeeCap    uint64
+		BaseFee   uint64
+		GasReward int64
+	}{
+		{Premium: 100, FeeCap: 200, BaseFee: 100, GasReward: 100},
+		{Premium: 100, FeeCap: 200, BaseFee: 210, GasReward: -10},
+		{Premium: 200, FeeCap: 250, BaseFee: 210, GasReward: 40},
+		{Premium: 200, FeeCap: 250, BaseFee: 2000, GasReward: -1750},
+	}
+
+	mp := new(MessagePool)
+	for _, test := range tests {
+		test := test
+		t.Run(fmt.Sprintf("%v", test), func(t *testing.T) {
+			msg := &types.SignedMessage{
+				Message: types.Message{
+					GasLimit:   10,
+					GasFeeCap:  types.NewInt(test.FeeCap),
+					GasPremium: types.NewInt(test.Premium),
+				},
+			}
+			rew := mp.getGasReward(msg, types.NewInt(test.BaseFee))
+			if rew.Cmp(big.NewInt(test.GasReward*10)) != 0 {
+				t.Errorf("bad reward: expected %d, got %s", test.GasReward*10, rew)
+			}
+		})
+	}
+}