fix: add timestamps for DELETE operations in history (#4492)

mem0/memory/main.py

@@ -1320,12 +1320,19 @@ class Memory(MemoryBase):
             if existing_memory is None:
                 raise ValueError(f"Memory with id {memory_id} not found")
         prev_value = existing_memory.payload.get("data", "")
+
+        # Preserve original created_at and record deletion time
+        created_at = _normalize_iso_timestamp_to_utc(existing_memory.payload.get("created_at"))
+        updated_at = datetime.now(timezone.utc).isoformat()
+
         self.vector_store.delete(vector_id=memory_id)
         self.db.add_history(
             memory_id,
             prev_value,
             None,
             "DELETE",
+            created_at=created_at,
+            updated_at=updated_at,
             actor_id=existing_memory.payload.get("actor_id"),
             role=existing_memory.payload.get("role"),
             is_deleted=1,
@@ -2460,6 +2467,10 @@ class AsyncMemory(MemoryBase):
                 raise ValueError(f"Memory with id {memory_id} not found")
         prev_value = existing_memory.payload.get("data", "")
 
+        # Preserve original created_at and record deletion time
+        created_at = _normalize_iso_timestamp_to_utc(existing_memory.payload.get("created_at"))
+        updated_at = datetime.now(timezone.utc).isoformat()
+
         await asyncio.to_thread(self.vector_store.delete, vector_id=memory_id)
         await asyncio.to_thread(
             self.db.add_history,
@@ -2467,6 +2478,8 @@ class AsyncMemory(MemoryBase):
             prev_value,
             None,
             "DELETE",
+            created_at=created_at,
+            updated_at=updated_at,
             actor_id=existing_memory.payload.get("actor_id"),
             role=existing_memory.payload.get("role"),
             is_deleted=1,

tests/test_memory.py

@@ -1,4 +1,5 @@
 import json
+from datetime import datetime
 from unittest.mock import MagicMock, patch
 
 import pytest
@@ -572,3 +573,143 @@ def test_update_infer_true_caches_embedding_on_llm_rewrite(mock_sqlite, mock_llm
     # It should NOT be called a 3rd time inside _update_memory
     assert embedder.embed.call_count == 2
     mock_vector_store.update.assert_called_once()
+
+
+@patch('mem0.utils.factory.EmbedderFactory.create')
+@patch('mem0.utils.factory.VectorStoreFactory.create')
+@patch('mem0.utils.factory.LlmFactory.create')
+@patch('mem0.memory.main.SQLiteManager')
+def test_delete_memory_history_has_timestamps(mock_sqlite, mock_llm_factory, mock_vector_factory, mock_embedder_factory):
+    """
+    Test that deleting a memory records created_at and updated_at in history.
+
+    Ensures DELETE operations preserve the original creation timestamp
+    and record the deletion time for proper audit trails.
+    """
+    mock_embedder_factory.return_value = MagicMock()
+    mock_vector_store = MagicMock()
+    mock_vector_factory.return_value = mock_vector_store
+    mock_llm_factory.return_value = MagicMock()
+    mock_sqlite.return_value = MagicMock()
+
+    from mem0.memory.main import Memory as MemoryClass
+    config = MemoryConfig()
+    memory = MemoryClass(config)
+
+    existing_memory = MagicMock()
+    existing_memory.payload = {
+        "data": "I like Python.",
+        "created_at": "2024-01-01T00:00:00+00:00",
+        "actor_id": None,
+        "role": None,
+    }
+    mock_vector_store.get.return_value = existing_memory
+
+    memory.delete("mem-123")
+
+    call_kwargs = memory.db.add_history.call_args.kwargs
+    assert call_kwargs["created_at"] == "2024-01-01T00:00:00+00:00"
+    assert call_kwargs["updated_at"] is not None
+    datetime.fromisoformat(call_kwargs["updated_at"])  # verify valid ISO timestamp
+
+
+@patch('mem0.utils.factory.EmbedderFactory.create')
+@patch('mem0.utils.factory.VectorStoreFactory.create')
+@patch('mem0.utils.factory.LlmFactory.create')
+@patch('mem0.memory.main.SQLiteManager')
+def test_delete_memory_normalizes_non_utc_created_at(mock_sqlite, mock_llm_factory, mock_vector_factory, mock_embedder_factory):
+    """Test that non-UTC created_at timestamps are normalized to UTC on delete."""
+    mock_embedder_factory.return_value = MagicMock()
+    mock_vector_store = MagicMock()
+    mock_vector_factory.return_value = mock_vector_store
+    mock_llm_factory.return_value = MagicMock()
+    mock_sqlite.return_value = MagicMock()
+
+    from mem0.memory.main import Memory as MemoryClass
+    config = MemoryConfig()
+    memory = MemoryClass(config)
+
+    existing_memory = MagicMock()
+    existing_memory.payload = {
+        "data": "I like Python.",
+        "created_at": "2024-01-01T05:00:00+05:00",  # UTC+5
+        "actor_id": None,
+        "role": None,
+    }
+    mock_vector_store.get.return_value = existing_memory
+
+    memory.delete("mem-123")
+
+    call_kwargs = memory.db.add_history.call_args.kwargs
+    assert call_kwargs["created_at"] == "2024-01-01T00:00:00+00:00"  # normalized to UTC
+
+
+@patch('mem0.utils.factory.EmbedderFactory.create')
+@patch('mem0.utils.factory.VectorStoreFactory.create')
+@patch('mem0.utils.factory.LlmFactory.create')
+@patch('mem0.memory.main.SQLiteManager')
+def test_delete_memory_missing_created_at(mock_sqlite, mock_llm_factory, mock_vector_factory, mock_embedder_factory):
+    """Test that delete works when created_at is absent from the payload (pre-existing memories)."""
+    mock_embedder_factory.return_value = MagicMock()
+    mock_vector_store = MagicMock()
+    mock_vector_factory.return_value = mock_vector_store
+    mock_llm_factory.return_value = MagicMock()
+    mock_sqlite.return_value = MagicMock()
+
+    from mem0.memory.main import Memory as MemoryClass
+    config = MemoryConfig()
+    memory = MemoryClass(config)
+
+    existing_memory = MagicMock()
+    existing_memory.payload = {
+        "data": "I like Python.",
+        "actor_id": None,
+        "role": None,
+    }
+    mock_vector_store.get.return_value = existing_memory
+
+    memory.delete("mem-123")
+
+    call_kwargs = memory.db.add_history.call_args.kwargs
+    assert call_kwargs["created_at"] is None
+    assert call_kwargs["updated_at"] is not None
+    datetime.fromisoformat(call_kwargs["updated_at"])  # verify valid ISO timestamp
+
+
+@pytest.mark.asyncio
+@patch('mem0.utils.factory.EmbedderFactory.create')
+@patch('mem0.utils.factory.VectorStoreFactory.create')
+@patch('mem0.utils.factory.LlmFactory.create')
+@patch('mem0.memory.main.SQLiteManager')
+async def test_async_delete_memory_history_has_timestamps(mock_sqlite, mock_llm_factory, mock_vector_factory, mock_embedder_factory):
+    """
+    Test that async deleting a memory records created_at and updated_at in history.
+
+    Ensures async DELETE operations preserve the original creation timestamp
+    and record the deletion time for proper audit trails.
+    """
+    mock_embedder_factory.return_value = MagicMock()
+    mock_vector_store = MagicMock()
+    mock_vector_factory.return_value = mock_vector_store
+    mock_llm_factory.return_value = MagicMock()
+    mock_sqlite.return_value = MagicMock()
+
+    from mem0.memory.main import AsyncMemory
+    config = MemoryConfig()
+    memory = AsyncMemory(config)
+
+    existing_memory = MagicMock()
+    existing_memory.payload = {
+        "data": "I like Python.",
+        "created_at": "2024-01-01T00:00:00+00:00",
+        "actor_id": None,
+        "role": None,
+    }
+    mock_vector_store.get.return_value = existing_memory
+
+    await memory.delete("mem-123")
+
+    call_kwargs = memory.db.add_history.call_args.kwargs
+    assert call_kwargs["created_at"] == "2024-01-01T00:00:00+00:00"
+    assert call_kwargs["updated_at"] is not None
+    datetime.fromisoformat(call_kwargs["updated_at"])  # verify valid ISO timestamp