Avoid buffer overflow with empty automaton.

1 files changed, 4 insertions, 0 deletions

diff --git a/fsa/src/vespa/fsa/automaton.cpp b/fsa/src/vespa/fsa/automaton.cpp
index 88777f4e198..ee80fee0db1 100644
--- a/fsa/src/vespa/fsa/automaton.cpp
+++ b/fsa/src/vespa/fsa/automaton.cpp
@@ -341,6 +341,10 @@ void Automaton::PackedAutomaton::finalize()
         _packed_idx[i] = _pack_map[_packed_ptr[i]];
       }
     }
+    if (_blob_used == 0) {
+        _packable = false;
+        return;
+    }
 
     // compact blobs if the size is constant
     std::map<uint32_t,uint32_t> bcomp;