fix: handle empty vector in decode_vector

tests/peewee/test_peewee.py

@@ -48,6 +48,13 @@ def teardown_class(self):
     def setup_method(self):
         Item1Model.truncate_table()
 
+    def test_empty_vector(self):
+        Item1Model.create(embedding=[])
+        assert Item1Model.select().count() == 1
+        item1 = Item1Model.get()
+        assert np.array_equal(item1.embedding, np.array([]))
+        assert item1.embedding.dtype == np.float32
+
     def test_insert_get_record(self):
         Item1Model.create(embedding=[1, 2, 3])
         assert Item1Model.select().count() == 1

tests/sqlalchemy/test_sqlalchemy.py

@@ -56,6 +56,16 @@ def test_insert_get_record(self):
             assert np.array_equal(item1.embedding, np.array([1, 2, 3]))
             assert item1.embedding.dtype == np.float32
 
+    def test_empty_vector(self):
+        with Session() as session:
+            item1 = Item1Model(embedding=[])
+            session.add(item1)
+            session.commit()
+            assert session.query(Item1Model).count() == 1
+            item1 = session.query(Item1Model).first()
+            assert np.array_equal(item1.embedding, np.array([]))
+            assert item1.embedding.dtype == np.float32
+
     def test_get_with_different_dimensions(self):
         with Session() as session:
             item1 = Item1Model(embedding=[1, 2, 3])

tidb_vector/utils.py

@@ -29,4 +29,7 @@ def decode_vector(value):
     if isinstance(value, bytes):
         value = value.decode("utf-8")
 
+    if value == "[]":
+        return np.array([], dtype=np.float32)
+
     return np.array(value[1:-1].split(","), dtype=np.float32)