I've pushed the first (and main) part of the patch series, after some more cleanup and comment polishing.
As explained in my previous message, I'm not sure about 0002. I don't know if we need to worry about it (no reports AFAICS). And while the patch works I'm not sure it's the best fix, or whether we need to do something about exhausting hash bits. In any case, it's not PG18 material. And it's a separate issue, so I'm marking this as committed. Thanks everyone who helped with any of the many old patch versions! -- Tomas Vondra