Description

When vector_store.get() returns None (memory ID not found), the code accesses .payload on None, causing an unhelpful AttributeError: 'NoneType' object has no attribute 'payload'.

This affects delete(), update(), and the session ID update handler in add() — all 3 code paths hit the same crash. Confirmed that all 6 vector store implementations (Qdrant, MongoDB, PGVector,
FAISS, Pinecone, Supabase) can return None from get().

This fix adds null checks after every vector_store.get() call that accesses .payload in both Memory and AsyncMemory:

• _delete_memory() — raises ValueError with descriptive message
• _update_memory() — raises ValueError with descriptive message
• add() NONE event handler — logs warning and skips gracefully

Fixes #3849

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• Unit Test

Added 4 new tests:

• test_delete_nonexistent_memory_raises_error — verifies sync delete() raises ValueError when memory ID doesn't exist, and does not call vector_store.delete()
• test_async_delete_nonexistent_memory_raises_error — verifies the same for AsyncMemory.delete()
• test_update_nonexistent_memory_raises_error — verifies sync _update_memory() raises ValueError when memory ID doesn't exist, and does not call vector_store.update()
• test_async_update_nonexistent_memory_raises_error — verifies the same for AsyncMemory._update_memory()

pytest tests/test_memory.py -v

21/21 passed

Bug reproduction verified — without the fix, both delete() and update() crash with AttributeError: 'NoneType' object has no attribute 'payload'. With the fix, they raise a clear ValueError.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

Maintainer Checklist

• closes # Bug Report: memory.delete() fails with AttributeError: 'NoneType' object has no attribute 'payload' when using Qdrant #3849
• Made sure Checks passed