fix(graph_dbs, feedback): fix Neo4j CypherTypeError and empty added_ids IndexError (#1122)

src/memos/graph_dbs/neo4j_community.py

@@ -56,6 +56,9 @@ def add_node(
         # Safely process metadata
         metadata = _prepare_node_metadata(metadata)
 
+        # Flatten info fields to top level (for Neo4j flat structure)
+        metadata = _flatten_info_fields(metadata)
+
         # Initialize delete_time and delete_record_id fields
         metadata.setdefault("delete_time", "")
         metadata.setdefault("delete_record_id", "")

src/memos/mem_feedback/feedback.py

@@ -250,6 +250,15 @@ def _single_add_operation(
         )
 
         logger.info(f"[Memory Feedback ADD] memory id: {added_ids!s}")
+        if not added_ids:
+            logger.warning(
+                "[Memory Feedback ADD] add returned empty list, memory may not have been persisted"
+            )
+            return {
+                "id": None,
+                "text": to_add_memory.memory,
+                "source_doc_id": None,
+            }
         return {
             "id": added_ids[0],
             "text": to_add_memory.memory,

tests/graph_dbs/test_neo4j_community_flatten_info.py

@@ -0,0 +1,97 @@
+"""
+Regression tests for issue #1122:
+Neo4jCommunityGraphDB.add_node() must flatten nested 'info' dict in metadata
+to avoid Neo4j CypherTypeError on Map-type property values.
+"""
+
+import uuid
+
+from datetime import datetime
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from memos.configs.graph_db import Neo4jGraphDBConfig
+
+
+@pytest.fixture
+def neo4j_community_config():
+    return Neo4jGraphDBConfig(
+        uri="bolt://localhost:7687",
+        user="neo4j",
+        password="test",
+        db_name="neo4j",
+        auto_create=False,
+        use_multi_db=False,
+        user_name="test-user",
+        embedding_dimension=3,
+    )
+
+
+@pytest.fixture
+def neo4j_community_db(neo4j_community_config):
+    with patch("neo4j.GraphDatabase") as mock_gd:
+        mock_driver = MagicMock()
+        mock_gd.driver.return_value = mock_driver
+
+        from memos.graph_dbs.neo4j_community import Neo4jCommunityGraphDB
+
+        db = object.__new__(Neo4jCommunityGraphDB)
+        db.config = neo4j_community_config
+        db.driver = mock_driver
+        db.db_name = neo4j_community_config.db_name
+        db.vec_db = MagicMock()
+        yield db
+
+
+class TestNeo4jCommunityFlattenInfo:
+    """Regression: add_node must flatten nested info dict before passing to Neo4j."""
+
+    def test_add_node_flattens_info_field(self, neo4j_community_db):
+        """Nested 'info' dict should be flattened to top-level keys in metadata."""
+        node_id = str(uuid.uuid4())
+        memory = "User prefers Python for AI development"
+        now = datetime.utcnow().isoformat()
+        metadata = {
+            "embedding": [0.1, 0.2, 0.3],
+            "created_at": now,
+            "updated_at": now,
+            "sources": [],
+            "info": {
+                "preference": "python",
+            },
+        }
+
+        session_mock = neo4j_community_db.driver.session.return_value.__enter__.return_value
+
+        neo4j_community_db.add_node(
+            id=node_id, memory=memory, metadata=metadata, user_name="test-user"
+        )
+
+        call_args = session_mock.run.call_args
+        passed_metadata = call_args.kwargs.get("metadata", call_args[1].get("metadata", {}))
+
+        assert "info" not in passed_metadata, (
+            f"'info' field was not flattened: metadata={passed_metadata}"
+        )
+        assert passed_metadata.get("preference") == "python"
+
+    def test_add_node_without_info_field_still_works(self, neo4j_community_db):
+        """add_node should work normally when metadata has no 'info' field."""
+        node_id = str(uuid.uuid4())
+        memory = "Simple memory"
+        now = datetime.utcnow().isoformat()
+        metadata = {
+            "embedding": [0.1, 0.2, 0.3],
+            "created_at": now,
+            "updated_at": now,
+            "sources": [],
+        }
+
+        session_mock = neo4j_community_db.driver.session.return_value.__enter__.return_value
+
+        neo4j_community_db.add_node(
+            id=node_id, memory=memory, metadata=metadata, user_name="test-user"
+        )
+
+        assert session_mock.run.called

tests/mem_feedback/test_feedback_empty_added_ids.py

@@ -0,0 +1,78 @@
+"""
+Regression tests for issue #1122 (Bug #2):
+MemFeedback._single_add_operation() must handle empty added_ids
+without raising IndexError.
+"""
+
+import uuid
+
+from datetime import datetime
+from unittest.mock import MagicMock
+
+import pytest
+
+from memos.mem_feedback.feedback import MemFeedback
+from memos.memories.textual.item import TextualMemoryItem, TreeNodeTextualMemoryMetadata
+
+
+def _make_memory_item(memory_text="I prefer Python for AI development"):
+    """Create a minimal TextualMemoryItem for testing."""
+    return TextualMemoryItem(
+        id=str(uuid.uuid4()),
+        memory=memory_text,
+        metadata=TreeNodeTextualMemoryMetadata(
+            user_id="user1",
+            memory_type="WorkingMemory",
+            sources=[],
+            embedding=[0.1, 0.2, 0.3],
+            created_at=datetime.now().isoformat(),
+            background="",
+            key="test-key",
+            tags=[],
+        ),
+    )
+
+
+@pytest.fixture
+def feedback_instance():
+    """Create a MemFeedback instance bypassing __init__."""
+    fb = object.__new__(MemFeedback)
+    fb.memory_manager = MagicMock()
+    fb.embedder = MagicMock()
+    return fb
+
+
+class TestSingleAddOperationEmptyIds:
+    """Test _single_add_operation when memory_manager.add() returns empty list."""
+
+    def test_empty_added_ids_returns_none_id(self, feedback_instance):
+        """When added_ids is empty, should return {"id": None} instead of IndexError."""
+        feedback_instance.memory_manager.add.return_value = []
+
+        new_item = _make_memory_item()
+        result = feedback_instance._single_add_operation(
+            old_memory_item=None,
+            new_memory_item=new_item,
+            user_id="user1",
+            user_name="test-user",
+        )
+
+        assert result["id"] is None
+        assert result["text"] == new_item.memory
+        assert result["source_doc_id"] is None
+
+    def test_normal_added_ids_returns_first_id(self, feedback_instance):
+        """When added_ids has values, should return the first id normally."""
+        expected_id = str(uuid.uuid4())
+        feedback_instance.memory_manager.add.return_value = [expected_id]
+
+        new_item = _make_memory_item()
+        result = feedback_instance._single_add_operation(
+            old_memory_item=None,
+            new_memory_item=new_item,
+            user_id="user1",
+            user_name="test-user",
+        )
+
+        assert result["id"] == expected_id
+        assert result["text"] == new_item.memory