Fixed one bug

Author: darkcoderrises

posting/list.go

@@ -321,6 +321,10 @@ func NewPosting(t *pb.DirectedEdge) *pb.Posting {
 	return p
 }
 
+func HasDeleteAll(mpost *pb.Posting) bool {
+	return hasDeleteAll(mpost)
+}
+
 func hasDeleteAll(mpost *pb.Posting) bool {
 	return mpost.Op == Del && bytes.Equal(mpost.Value, []byte(x.Star)) && len(mpost.LangTag) == 0
 }

posting/lists.go

@@ -253,11 +253,20 @@ func (lc *LocalCache) getInternal(key []byte, readFromDisk bool) (*List, error)
 
 func (lc *LocalCache) GetSinglePosting(key []byte) (*pb.PostingList, error) {
 	pl := &pb.PostingList{}
+	validatePl := func() {
+		for _, postings := range pl.Postings {
+			if hasDeleteAll(postings) {
+				pl = nil
+				return
+			}
+		}
+	}
 	lc.RLock()
 	if delta, ok := lc.deltas[string(key)]; ok && len(delta) > 0 {
 		err := pl.Unmarshal(delta)
 		lc.RUnlock()
 		if err != nil {
+			validatePl()
 			return pl, nil
 		}
 	} else {
@@ -267,6 +276,7 @@ func (lc *LocalCache) GetSinglePosting(key []byte) (*pb.PostingList, error) {
 	txn := pstore.NewTransactionAt(lc.startTs, false)
 	item, err := txn.Get(key)
 	if err != nil {
+		validatePl()
 		return pl, err
 	}
 
@@ -278,9 +288,11 @@ func (lc *LocalCache) GetSinglePosting(key []byte) (*pb.PostingList, error) {
 	})
 
 	if err != nil {
+		validatePl()
 		return pl, err
 	}
 
+	validatePl()
 	return pl, nil
 }
 

worker/task.go

@@ -398,7 +398,21 @@ func (qs *queryState) handleValuePostings(ctx context.Context, args funcArgs) er
 			fcs := &pb.FacetsList{FacetsList: make([]*pb.Facets, 0)} // TODO Figure out how it is stored
 
 			if !pickMultiplePostings {
-				pl, _ := qs.cache.GetSinglePosting(key)
+				pl, err := qs.cache.GetSinglePosting(key)
+				if pl == nil || err == posting.ErrNoValue {
+					out.UidMatrix = append(out.UidMatrix, &pb.List{})
+					out.FacetMatrix = append(out.FacetMatrix, &pb.FacetsList{})
+					out.ValueMatrix = append(out.ValueMatrix,
+						&pb.ValueList{Values: []*pb.TaskValue{}})
+					if q.ExpandAll {
+						// To keep the cardinality same as that of ValueMatrix.
+						out.LangMatrix = append(out.LangMatrix, &pb.LangList{})
+					}
+					continue
+				}
+				if err != nil {
+					return err
+				}
 				vals = make([]types.Val, len(pl.Postings))
 				for i, p := range pl.Postings {
 					vals[i] = types.Val{