fix from challenger review (#17)

Author: sh-cha

challenger/child/withdraw.go

@@ -119,7 +119,7 @@ func (ch *Child) handleTree(blockHeight uint64, blockHeader cmtproto.Header) (kv
 	// panic if we passed the finalizing block height
 	// this must not happened
 	if ch.finalizingBlockHeight != 0 && ch.finalizingBlockHeight < blockHeight {
-		panic(fmt.Errorf("INVARIANT failed; handleTree expect to finalize tree at block `%d` but we got block `%d`", blockHeight-1, blockHeight))
+		panic(fmt.Errorf("INVARIANT failed; handleTree expect to finalize tree at block `%d` but we got block `%d`", ch.finalizingBlockHeight, blockHeight))
 	}
 
 	if ch.finalizingBlockHeight == blockHeight {

challenger/eventhandler/challenge.go

@@ -36,6 +36,7 @@ func (ch *ChallengeEventHandler) CheckValue(events []challengertypes.ChallengeEv
 		}
 		processedEvents = append(processedEvents, pendingEvent)
 
+		// clearing pending oracle events up to l1 height of the last oracle event
 		if event.Type() == challengertypes.EventTypeOracle {
 			oracleEvents := ch.getOraclePendingEvents(event.Id().Id)
 			processedEvents = append(processedEvents, oracleEvents...)
@@ -48,8 +49,8 @@ func (ch *ChallengeEventHandler) CheckValue(events []challengertypes.ChallengeEv
 func (ch *ChallengeEventHandler) GetPrevPendingEvent(event challengertypes.ChallengeEvent) (challengertypes.ChallengeEvent, bool) {
 	prevId := event.Id()
 	prevId.Id--
-	prevOutputEvent, ok := ch.GetPendingEvent(prevId)
-	return prevOutputEvent, ok
+	prevEvent, ok := ch.GetPendingEvent(prevId)
+	return prevEvent, ok
 }
 
 func (ch *ChallengeEventHandler) CheckTimeout(blockTime time.Time, events []challengertypes.ChallengeEvent) ([]challengertypes.Challenge, []challengertypes.ChallengeEvent) {

challenger/handler.go

@@ -48,9 +48,9 @@ func (c *Challenger) insertLatestChallenges(challenge challengertypes.Challenge)
 	sort.Slice(c.latestChallenges, func(i, j int) bool {
 		if c.latestChallenges[i].Time.Equal(c.latestChallenges[j].Time) {
 			if c.latestChallenges[i].Id.Type == c.latestChallenges[j].Id.Type {
-				return c.latestChallenges[i].Id.Type < c.latestChallenges[j].Id.Type
+				return c.latestChallenges[i].Id.Id < c.latestChallenges[j].Id.Id
 			}
-			return c.latestChallenges[i].Id.Id < c.latestChallenges[j].Id.Id
+			return c.latestChallenges[i].Id.Type < c.latestChallenges[j].Id.Type
 		}
 		return c.latestChallenges[i].Time.Before(c.latestChallenges[j].Time)
 	})

db/db.go

@@ -89,6 +89,7 @@ func (db *LevelDB) Close() error {
 // @dev: `LevelDB.prefix + prefix` is used as the prefix for the iteration.
 func (db *LevelDB) PrefixedIterate(prefix []byte, cb func(key, value []byte) (stop bool, err error)) error {
 	iter := db.db.NewIterator(util.BytesPrefix(db.PrefixedKey(prefix)), nil)
+	defer iter.Release()
 	for iter.Next() {
 		key := db.UnprefixedKey(iter.Key())
 		if stop, err := cb(key, iter.Value()); err != nil {
@@ -97,12 +98,12 @@ func (db *LevelDB) PrefixedIterate(prefix []byte, cb func(key, value []byte) (st
 			break
 		}
 	}
-	iter.Release()
 	return iter.Error()
 }
 
 func (db *LevelDB) PrefixedReverseIterate(prefix []byte, cb func(key, value []byte) (stop bool, err error)) error {
 	iter := db.db.NewIterator(util.BytesPrefix(db.PrefixedKey(prefix)), nil)
+	defer iter.Release()
 	if iter.Last() {
 		for {
 			key := db.UnprefixedKey(iter.Key())
@@ -117,7 +118,6 @@ func (db *LevelDB) PrefixedReverseIterate(prefix []byte, cb func(key, value []by
 			}
 		}
 	}
-	iter.Release()
 	return iter.Error()
 }
 
@@ -126,13 +126,13 @@ func (db *LevelDB) PrefixedReverseIterate(prefix []byte, cb func(key, value []by
 // @dev: `LevelDB.prefix + prefix` is used as the prefix for the iteration.
 func (db *LevelDB) SeekPrevInclusiveKey(prefix []byte, key []byte) (k []byte, v []byte, err error) {
 	iter := db.db.NewIterator(util.BytesPrefix(db.PrefixedKey(prefix)), nil)
+	defer iter.Release()
 	if iter.Seek(db.PrefixedKey(key)) || iter.Valid() && iter.Prev() || iter.Last() && iter.Valid() {
 		k = db.UnprefixedKey(iter.Key())
 		v = iter.Value()
 	} else {
 		err = dbtypes.ErrNotFound
 	}
-	iter.Release()
 	if iter.Error() != nil {
 		err = iter.Error()
 	}