Not sure if that's intentional, and whether this is still reproducible…
I found out today that EPEL9 already ships a few Rust packages even though rust-packaging is not (was not) available in the repos.
rust-packaging
https://kojipkgs.fedoraproject.org//packages/rust-plotters-backend/0.3.2/3.el9/data/logs/aarch64/root.log
indicates that rust-packaging-17-5.el9 was used from the build repo which means it was configured as part of external repo in koji. That package is not present in BaseOS/AppStream/CRB which I understand means it is supposed to be RHEL internal package and not supposed to be used in the EPEL builds.
build
When the initial EPEL9-next and EPEL9 packages were being built, they were using a copy of the koji tree from CentOS Stream9's koji. That contained packages like rust-packaging and such. At some point 2-3 weeks ago, it was decided to just use the shipped repos. However builds had already been done and we now have packages which can't be rebuilt until an epel-rust-packaging is created.
This build ahs happened on 18 December so I'm not sure if the changes were implemented or not.. but if you think it is OK now, feel free to close this ticket.
I'm starting to feel more strongly that we should be able to build against the RHEL packages that aren't shipped. I have no idea if it's possible in practice, but we're generating a huge amount of make-work for EPEL. Especially since my impression (no numbers to back it up) is that there are even more un-shipped packages in RHEL9.
Metadata Update from @humaton: - Issue close_status updated to: Fixed - Issue status updated to: Closed (was: Open)