Handle removal of docid with empty tensor in HNSW index.

2 files changed, 11 insertions, 1 deletions

diff --git a/searchlib/src/tests/tensor/hnsw_index/hnsw_index_test.cpp b/searchlib/src/tests/tensor/hnsw_index/hnsw_index_test.cpp
index f3487f6e585..d9230849699 100644
--- a/searchlib/src/tests/tensor/hnsw_index/hnsw_index_test.cpp
+++ b/searchlib/src/tests/tensor/hnsw_index/hnsw_index_test.cpp
@@ -816,6 +816,14 @@ TEST_F(HnswMultiIndexTest, duplicate_docid_is_removed)
     EXPECT_EQ(2, filter->max_docid());
 };
 
+TEST_F(HnswMultiIndexTest, docid_with_empty_tensor_can_be_removed)
+{
+    this->init(false);
+    this->vectors.set(1, {});
+    this->add_document(1);
+    this->remove_document(1);
+}
+
 TEST(LevelGeneratorTest, gives_various_levels)
 {
     InvLogLevelGenerator generator(4);
diff --git a/searchlib/src/vespa/searchlib/tensor/hnsw_nodeid_mapping.cpp b/searchlib/src/vespa/searchlib/tensor/hnsw_nodeid_mapping.cpp
index e3afbc3b4c5..8c169e63f9a 100644
--- a/searchlib/src/vespa/searchlib/tensor/hnsw_nodeid_mapping.cpp
+++ b/searchlib/src/vespa/searchlib/tensor/hnsw_nodeid_mapping.cpp
@@ -91,7 +91,9 @@ HnswNodeidMapping::free_ids(uint32_t docid)
 {
     assert(docid < _refs.size());
     EntryRef ref = _refs[docid];
-    assert(ref.valid());
+    if (!ref.valid()) {
+        return;
+    }
     auto nodeids = _nodeids.get(ref);
     for (auto nodeid : nodeids) {
         _hold_list.insert(nodeid);