get_default_cube_config: clear ValueError instead of UnboundLocalError for invalid text_mem_type

src/memos/mem_os/utils/default_config.py

@@ -231,6 +231,11 @@ def get_default_cube_config(
             },
         }
 
+    else:
+        raise ValueError(
+            f"text_mem_type must be 'tree_text' or 'general_text', got {text_mem_type!r}"
+        )
+
     # Configure activation memory if enabled.
     # KV cache activation memory requires a local HuggingFace/vLLM model (it
     # extracts internal attention KV tensors via build_kv_cache), so it cannot

tests/mem_os/test_default_config_text_mem_type.py

@@ -0,0 +1,17 @@
+import pytest
+
+from memos.mem_os.utils.default_config import get_default_cube_config
+
+
+@pytest.mark.parametrize("bad_type", ["tree-text", "Tree_Text", ""])
+def test_invalid_text_mem_type_raises_clear_error(bad_type):
+    # an unrecognized text_mem_type used to crash with a bare
+    # UnboundLocalError because text_mem_config was never assigned
+    with pytest.raises(ValueError, match="text_mem_type must be"):
+        get_default_cube_config(openai_api_key="sk-x", text_mem_type=bad_type)
+
+
+@pytest.mark.parametrize("mem_type", ["tree_text", "general_text"])
+def test_valid_text_mem_types_build_cube_config(mem_type):
+    config = get_default_cube_config(openai_api_key="sk-x", text_mem_type=mem_type)
+    assert config.text_mem.backend == mem_type