Keep concurrent note deletes idempotent

Signed-off-by: phernandez <paul@basicmachines.co>

Author: phernandez

src/basic_memory/indexing/accepted_note_mutation_runner.py

@@ -625,13 +625,28 @@ async def run_accepted_note_delete(
 
     # The entity lookup above is intentionally unlocked so an already-missing
     # delete stays idempotent. Once the note exists, claim its mutation lock and
-    # refresh both evidence rows before deleting: a concurrent update or move may
-    # have committed between the initial lookup and this lock acquisition.
+    # reload it before deleting: another delete may have removed the row while we
+    # waited, while an update or move may have changed its accepted evidence.
     await lock_accepted_note_content_for_entity_mutation(
         session,
         project_id=project.id,
         entity_id=entity.id,
     )
+    entity = await entity_repository.get_by_external_id(
+        session,
+        request.entity_external_id,
+        load_relations=False,
+    )
+    if entity is None:
+        return AcceptedNoteMutationResult(
+            change=await delete_accepted_note(
+                session,
+                project_id=project.id,
+                entity=None,
+                repositories=dependencies.write_repositories,
+            )
+        )
+
     await session.refresh(entity)
     note_content = await load_accepted_note_content(
         session,

tests/indexing/test_accepted_note_mutation_runner.py

@@ -2075,6 +2075,41 @@ async def test_run_accepted_note_delete_removes_entity_and_returns_cleanup() ->
     assert result.relation_publication is None
 
 
+@pytest.mark.asyncio
+async def test_run_accepted_note_delete_stays_idempotent_after_concurrent_delete() -> None:
+    session = _MutationSession()
+    project = _project()
+    entity = _entity(file_path="notes/accepted.md")
+    entity_lookup_repository = _EntityLookupRepository(by_external_id=entity)
+    entity_lookup_repository.get_by_external_id = AsyncMock(side_effect=[entity, None])
+    search_repository = _SearchRepository()
+
+    result = await run_accepted_note_delete(
+        cast(AsyncSession, session),
+        request=AcceptedNoteDeleteMutation(
+            project_external_id="project-123",
+            entity_external_id="note-123",
+        ),
+        dependencies=_dependencies(
+            project_repository=_ProjectRepository(project),
+            entity_lookup_repository=entity_lookup_repository,
+            note_content_lookup_repository=_NoteContentLookupRepository(),
+            preparer_factory=_PreparerFactory(_CreatePreparer(_prepared())),
+            pending_entity_repository=_PendingEntityRepository(entity),
+            note_content_accept_repository=_NoteContentAcceptRepository(_note_content(entity)),
+            search_repository=search_repository,
+        ),
+    )
+
+    assert result.change.status_code == 200
+    assert result.change.payload == {"deleted": False}
+    assert session.scalar_count == 1
+    assert session.refreshed == []
+    assert session.deleted == []
+    assert search_repository.deleted_entity_ids == []
+    assert search_repository.deleted_vector_entity_ids == []
+
+
 def _prepared_with_graph(
     *,
     observations: Sequence[AcceptedObservationWrite],