It is documented in the system requirements that we do not support 32-bit systems.

While it mentions some examples, these are not the only cases that assume a 64-bit Datum type. Making pgrx work on 32-bit very well requires more than these changes, and it requires pervasive changes, because we e.g. provide a pg_sys::Datum::from(i64). That cannot work except by truncating data on a 32-bit system.

While we have merged changes that make it a little easier to run pgrx on a 32-bit system before, this is the point where things become more than incidentally adding support. I really want to know why we'd be adding support. Finishing 32-bit support is going to cost hundreds of lines of code of revision and review.

And I'd want real tests, here, that I can run while on a 64-bit system, because otherwise I'm going to break it again. With a test suite that is a command away, I at least can lean on those.