added logging on import;crashing bug on sync on empty fragment

executor.go

@@ -71,7 +71,6 @@ func (e *Executor) Execute(db string, q *pql.Query, slices []uint64, opt *ExecOp
 		}
 		results = append(results, v)
 	}
-
 	return results, nil
 }
 

fragment.go

@@ -854,8 +854,8 @@ func (f *Fragment) Import(bitmapIDs, profileIDs []uint64) error {
 			if bitmap.SetBit(profileID) {
 				bmCounter += 1
 			}
-			// Update the cache.
 		}
+		f.cache.Invalidate()
 		return nil
 	}(); err != nil {
 		_ = f.closeStorage()

handler.go

@@ -398,12 +398,14 @@ func (h *Handler) handlePostImport(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// Find the correct fragment.
+	h.logger().Println("Go Import:", db, frame, slice)
 	f, err := h.Index.CreateFragmentIfNotExists(db, frame, slice)
 	if err != nil {
 		h.logger().Printf("fragment error: db=%s, frame=%s, slice=%d, err=%s", db, frame, slice, err)
 		http.Error(w, "fragment error", http.StatusInternalServerError)
 		return
 	}
+	h.logger().Println("Import into Fragment:", db, frame, slice, len(reg.GetProfileIDs()))
 
 	// Import into fragment.
 	err = f.Import(req.GetBitmapIDs(), req.GetProfileIDs())

roaring/roaring.go

@@ -638,6 +638,9 @@ func (c *container) max() uint16 {
 }
 
 func (c *container) arrayMax() uint16 {
+	if len(c.array) == 0 {
+		return 0 //probably hiding some ugly bug but it prevents a crash
+	}
 	return c.array[len(c.array)-1]
 }