Bad post URL gives database error instead of 404

[Bobcat]

If I enter a URL such as http://www.example.com/blog/2007/12/unknown/ where there is no such post, I expect to get a 404 error. Instead, I get the following database error:

WordPress database error: [You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'ORDER BY p.post_date ASC LIMIT 1' at line 1]
SELECT p.ID, p.post_title FROM wp_posts AS p WHERE p.post_date > '' AND p.post_type = 'post' AND p.post_status = 'publish' AND p.ID != ORDER BY p.post_date ASC LIMIT 1

This is a duplicate of another ticket.

Need ticket number before closing.

After doing some more research, I think my problem is that the _wp_old_slug redirect doesn't work. I see the old slug in the post_meta table, but the redirect doesn't happen.

It looks like the wp_old_slug_redirect redirect isn't happening because it's not being classified as a 404. And it's not a 404 because $wp_query->posts is not empty even though the post doesn't exist. $wp_query->posts has one element with only comment_status and ping_status, nothing else; there's no real post there.

Doesnt appear to be a problem on trunk for me. (Just tested)

Related: #5185, #5471

I just retested this with 2.5. I get a page with an empty post; HTTP response is '200'. Still not the '404' response I expected, which would allow an error message to be displayed to the user.

Works for me on trunk.

I'm getting 404 errors from 404'ing posts and pages on 2.8 trunk, It could be a theme issue that causes the empty post.