Is Rust app somewhat special? All other packages are downloaded from cache.nixos.org but Rust packages always involve local compilation (and make the CPU burn)
3 weeks ago I discovered that ofBorg is failing to build rust packages under sandbox on Darwin (see buildRustPackage derivations fail ofBorg's sandboxed Darwin build due to cert error · Issue #332 · NixOS/ofborg · GitHub). I assume this same issue is affecting hydra. I don’t know how to fix it.
I’d say it’s more that macOS is “special” around here, in the sense that there seem to be very few nixpkgs contributors for it, it has less resources on Hydra.nixos.org (because Apple HW is expensive and OS licensing complicates stuff), and apparently the packaging and Hydra machine maintenance is a bit more difficult than for linux, too.
As a combined consequence, the level of support for darwin is (currently) worse than for linux platforms. Well, if enough people get interested and working on fixing stuff, it’s surely possible to improve the overall situation. EDIT: hmm, perhaps this post was a bit too generic for this thread.
I don’t have a lot of free time but I’m certainly willing to do what I can to try and improve things, but I have no idea how to even begin to try and help with this problem.
Let’s be more concrete. It seems that rustc binaries are without problems: