https://bugzilla.redhat.com/show_bug.cgi?id=2080743
--- Comment #11 from Fabio Valentini decathorpe@gmail.com --- Having Conflicts would maybe help in one way (make the packages not installable on those architectures), but it would not help in another way (the packages would still have broken dependencies on those architectures).
This is also not a limitation of Rust packaging, this is a limitation of RPM itself and Fedora build infrastructure: https://pagure.io/koji/issue/1843 https://pagure.io/pungi/issue/1518
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If you don't have a concrete use case for this crate yet, I don't think packaging something that will end up unused makes much sense. Instead, I'd recommend to use one of the "trust-dns" libraries, instead: https://crates.io/crates/trust-dns-resolver
They have support for DNSSEC, "DNS over SSL", and "DNS over HTTPS" (the latter is not enabled yet in Fedora), support OpenSSL as a crypto backend, and are already packaged for Fedora, because they are the "library of choice" for this functionality in most HTTP(S) libraries and web frameworks.
On the other hand, the DNSSec support in the "domain" crate is labeled as "incomplete" and "experimental", which doesn't inspire confidence ...