Query with limit=1 returns empty for non-empty feed - app.bsky.feed.getAuthorFeed

[oestradiol]

Describe the bug

If you pass the query filters...

• limit=1;
• filter=posts_and_author_threads
• no cursor (although I didn't test with a cursor, but the idea is fetching the latest post, so I don't think this will be particularly relevant)

...to app.bsky.feed.getAuthorFeed, and the last post the person made was deleted, it returns an empty feed (as if they had 0 posts) instead of their actual last available post.

To Reproduce

Steps to reproduce the behavior:

1. Make sure you have at least one post;
2. Post or Repost anything;
3. Undo the previous action;
4. Issue a request: {{your_pds}}/xrpc/app.bsky.feed.getAuthorFeed?actor={{your_did}}&filter=posts_and_author_threads&limit=1

Expected behavior

One would expect the XRPC to return an array containing the last available post.

Additional context

I'm not sure because haven't read much of this codebase, but I think it might be related to this: The field nullsLast is undefined by default... https://github.com/bluesky-social/atproto/blob/c5b765d043d3a1e934d6444decf3940968230f5f/packages/bsky/src/data-plane/server/db/pagination.ts#L135-L152 ...and should be for getAuthorFeed too, since it's not set here: https://github.com/bluesky-social/atproto/blob/c5b765d043d3a1e934d6444decf3940968230f5f/packages/bsky/src/data-plane/server/routes/feeds.ts#L48-L52 Because of that, it reaches this query if statement: https://github.com/bluesky-social/atproto/blob/c5b765d043d3a1e934d6444decf3940968230f5f/packages/bsky/src/data-plane/server/db/pagination.ts#L156-L158

According to the Postgres documentation (and as mentioned on line 141 of pagination.ts above):

[oestradiol]

Update: Mary (@mary-ext) mentioned something relevant, so I'm adding this here.

"posts_and_author_threads have an additional filter that's done outside of a db query so part of it could be that"