When I was working on 832e220d99a, I actually considered for more detailed error messages, but I ended up giving up. I think we should be careful about adding more branches here unless the existing message is causing significant confusion in practice.
So, I personally don’t like 0002.
I hear the concern of adding more branches here. FWIW, neither the deferrable PK limitation nor the REPLICA IDENTITY FULL case is documented in repack.sgml, and the current error message doesn't surface either issue. The user has no way to discover what's wrong without reading the source. That's why I think the improved messages are warranted here. Happy to add a documentation note as well, or both. Let me know what's preferred.
But happy to drop 0002 if others feel the same. 0001 and 0003 stand on their own.
