fix(server): return 404/400 instead of 502 for not-found and invalid input (#5634)

tests/test_memory.py

@@ -536,6 +536,59 @@ async def test_async_update_nonexistent_memory_raises_error(mock_sqlite, mock_ll
     mock_vector_store.update.assert_not_called()
 
 
+@patch('mem0.utils.factory.EmbedderFactory.create')
+@patch('mem0.utils.factory.VectorStoreFactory.create')
+@patch('mem0.utils.factory.LlmFactory.create')
+@patch('mem0.memory.storage.SQLiteManager')
+def test_update_propagates_vector_store_failure(mock_sqlite, mock_llm_factory, mock_vector_factory, mock_embedder_factory):
+    """A backing-store failure while fetching the memory during update must
+    surface as the original error, not be masked as a 'provide a valid
+    memory_id' ValueError. The REST layer relies on this so an outage maps to
+    5xx instead of a misleading 4xx."""
+    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)
+
+    mock_vector_store.get.side_effect = ConnectionError("vector store unreachable")
+
+    with pytest.raises(ConnectionError, match="vector store unreachable"):
+        memory._update_memory("mem-1", "new data", {"new data": [0.1, 0.2]})
+
+    mock_vector_store.update.assert_not_called()
+
+
+@pytest.mark.asyncio
+@patch('mem0.utils.factory.EmbedderFactory.create')
+@patch('mem0.utils.factory.VectorStoreFactory.create')
+@patch('mem0.utils.factory.LlmFactory.create')
+@patch('mem0.memory.storage.SQLiteManager')
+async def test_async_update_propagates_vector_store_failure(mock_sqlite, mock_llm_factory, mock_vector_factory, mock_embedder_factory):
+    """Async twin: a backing-store failure during update re-raises the original
+    error instead of masking it as a ValueError."""
+    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)
+
+    mock_vector_store.get.side_effect = ConnectionError("vector store unreachable")
+
+    with pytest.raises(ConnectionError, match="vector store unreachable"):
+        await memory._update_memory("mem-1", "new data", {"new data": [0.1, 0.2]})
+
+    mock_vector_store.update.assert_not_called()
+
+
 @patch('mem0.utils.factory.EmbedderFactory.create')
 @patch('mem0.utils.factory.VectorStoreFactory.create')
 @patch('mem0.utils.factory.LlmFactory.create')

tests/test_server_params.py

@@ -12,6 +12,8 @@ from unittest.mock import MagicMock, patch
 
 import pytest
 
+from mem0.exceptions import ValidationError as Mem0ValidationError
+
 pytest.importorskip("fastapi", reason="fastapi not installed")
 
 from fastapi.testclient import TestClient
@@ -701,3 +703,44 @@ class TestSearchValidationErrors:
         )
         resp = client.post("/search", json={"query": "food"})
         assert resp.status_code == 400
+
+
+# ===========================================================================
+# add / update / delete: map core errors to 4xx instead of 502
+# ===========================================================================
+
+class TestWriteHandlerErrorMapping:
+    """ValueError("... not found") -> 404, other ValueError / Mem0ValidationError
+    -> 400. A real outage still surfaces as 502 via upstream_error()."""
+
+    def test_update_not_found_returns_404(self, client, mock_memory):
+        mock_memory.update.side_effect = ValueError("Memory with id mem-1 not found")
+        resp = client.put("/memories/mem-1", json={"text": "new"})
+        assert resp.status_code == 404
+        assert "not found" in resp.json()["detail"]
+
+    def test_delete_not_found_returns_404(self, client, mock_memory):
+        mock_memory.delete.side_effect = ValueError("Memory with id mem-1 not found")
+        resp = client.delete("/memories/mem-1")
+        assert resp.status_code == 404
+
+    def test_update_other_value_error_returns_400(self, client, mock_memory):
+        mock_memory.update.side_effect = ValueError("data must be a non-empty string")
+        resp = client.put("/memories/mem-1", json={"text": "new"})
+        assert resp.status_code == 400
+
+    def test_add_validation_error_returns_400(self, client, mock_memory):
+        mock_memory.add.side_effect = Mem0ValidationError(
+            message="messages must be str, dict, or list[dict]", error_code="VALIDATION_003"
+        )
+        resp = client.post("/memories", json={
+            "messages": [{"role": "user", "content": "hi"}], "user_id": "u1",
+        })
+        assert resp.status_code == 400
+
+    def test_add_real_outage_still_returns_502(self, client, mock_memory):
+        mock_memory.add.side_effect = RuntimeError("vector store unreachable")
+        resp = client.post("/memories", json={
+            "messages": [{"role": "user", "content": "hi"}], "user_id": "u1",
+        })
+        assert resp.status_code == 502