do not set maxFeeRate for cancels v2 upgrade

client/db/bolt/db.go

@@ -704,6 +704,16 @@ func decodeOrderBucket(oid []byte, oBkt *bbolt.Bucket) (*dexdb.MetaOrder, error)
 	var linkedID order.OrderID
 	copy(linkedID[:], oBkt.Get(linkedKey))
 
+	// Old cancel orders may not have a maxFeeRate set since the v2 upgrade
+	// doesn't set it for cancel orders.
+	var maxFeeRate uint64
+	if maxFeeRateB := oBkt.Get(maxFeeRateKey); len(maxFeeRateB) == 8 {
+		maxFeeRate = intCoder.Uint64(maxFeeRateB)
+	} else if ord.Type() != order.CancelOrderType {
+		// Cancel orders should use zero, but trades need a non-zero value.
+		maxFeeRate = ^uint64(0) // should not happen for trade orders after v2 upgrade
+	}
+
 	return &dexdb.MetaOrder{
 		MetaData: &dexdb.OrderMetaData{
 			Proof:              *proof,
@@ -712,7 +722,7 @@ func decodeOrderBucket(oid []byte, oBkt *bbolt.Bucket) (*dexdb.MetaOrder, error)
 			ChangeCoin:         getCopy(oBkt, changeKey),
 			LinkedOrder:        linkedID,
 			SwapFeesPaid:       intCoder.Uint64(oBkt.Get(swapFeesKey)),
-			MaxFeeRate:         intCoder.Uint64(oBkt.Get(maxFeeRateKey)),
+			MaxFeeRate:         maxFeeRate,
 			RedemptionFeesPaid: intCoder.Uint64(oBkt.Get(redemptionFeesKey)),
 		},
 		Order: ord,

client/db/bolt/upgrades.go

@@ -137,8 +137,8 @@ func v1Upgrade(dbtx *bbolt.Tx) error {
 }
 
 // v2Upgrade adds a MaxFeeRate field to the OrderMetaData. The upgrade sets the
-// MaxFeeRate field for all historical orders to the max uint64. This avoids any
-// chance of rejecting a pre-existing active match.
+// MaxFeeRate field for all historical trade orders to the max uint64. This
+// avoids any chance of rejecting a pre-existing active match.
 func v2Upgrade(dbtx *bbolt.Tx) error {
 	const oldVersion = 1
 
@@ -164,6 +164,18 @@ func v2Upgrade(dbtx *bbolt.Tx) error {
 		if oBkt == nil {
 			return fmt.Errorf("order %x bucket is not a bucket", oid)
 		}
+		// Cancel orders should be stored with a zero maxFeeRate, as done in
+		// (*Core).tryCancelTrade. Besides, the maxFeeRate should not be applied
+		// to cancel matches, as done in (*dexConnection).parseMatches.
+		oTypeB := oBkt.Get(typeKey)
+		if len(oTypeB) != 1 {
+			return fmt.Errorf("order %x type invalid: %x", oid, oTypeB)
+		}
+		if order.OrderType(oTypeB[0]) == order.CancelOrderType {
+			// Don't bother setting maxFeeRate for cancel orders.
+			// decodeOrderBucket will default to zero for cancels.
+			return nil
+		}
 		return oBkt.Put(maxFeeRateKey, maxFeeB)
 	})
 }