alt Hacker NewsAs I said, that sounds like a recipe for potential TOCTOU errors.
But again, this was an off-the-cuff example that I explicitly described as contrived from the start. I could probably flesh it out to make more sense, but I think it'd be easier just to refer to sibling comments rather than bikeshed this to death.
Not really? It returns no owner if the document is deleted or just does not exist, which is accurate. Why do you need get_owner to tell you if the document exists or not? If anything it should be an error if the document doesn’t exist because you’ve violated a precondition.