| 16 Jan 2026 |
|  @marcel:envs.net left the room. | 00:49:58 |
 emily | fwiw I did pkgs.rust-bin.fromRustupToolchain { channel = "nightly"; components = ["miri" "rust-src"]; } last time I needed Miri. maybe toolchain.default.override doesn't work properly there. not sure | 02:47:25 |
 Logan Devine | Still doesn't work, hm | 03:13:56 |
 accelbread | I've got my miri package definitions here if it helps: [https://github.com/accelbread/flakelight-rust/tree/master/packages](miri packages) | 05:43:42 |
| accelbread | * I've got my miri package definitions here if it helps: https://github.com/accelbread/flakelight-rust/tree/master/packages | 05:43:54 |
| accelbread | Has anyone gotten build-std working with nixpkgs rustc? | 05:57:29 |
| Logan Devine | thank ya, I'll try this out | 15:47:28 |
| 17 Jan 2026 |
|  roxie joined the room. | 03:33:14 |
| roxie set a profile picture. | 03:35:00 |
| roxie changed their profile picture. | 03:37:35 |
 debtquity | are there any tricks for speeding up local build times for rust packages in nixpkgs?
...
┏━ Dependency Graph:
┃ ✔ stalwart-0.15.3 ⏱ 21m29s
┣━━━ Builds
┗━ ∑ ⏵ 0 │ ✔ 1 │ ⏸ 0 │ Finished at 22:18:53 after 21m38s
20 minutes is wild
| 06:04:49 |
 Charles ⚡️ | try disabling runtime performance optimizations like codegen-units = 1 and lto = true https://github.com/stalwartlabs/stalwart/blob/22fc4a795d56264aefd082040c6998c9371b83aa/Cargo.toml#L46-L47 | 06:21:37 |
| Charles ⚡️ | not sure if that fits your "local" criteria though | 06:22:30 |
| debtquity | oh, i was hoping to do it from the building side without modifying the project | 06:22:44 |
| Charles ⚡️ | i don't know any such tricks unfortunately (but maybe someone else might?) | 06:23:11 |
| Charles ⚡️ | i mean, you could add patches to the derivation to make those changes via overrideAttrs, unless you really mean "without changing any nix code or upstream code" | 06:25:20 |
| debtquity | ah, i'll give that a shot. what do we lose with LTO, though? | 06:26:09 |
| Charles ⚡️ | https://doc.rust-lang.org/cargo/reference/profiles.html#lto | 06:26:46 |
| Charles ⚡️ | summary to the point of being unhelpful: you lose some performance | 06:27:20 |
 Marien Zwart | Should be about the same performance as a non-incremental release build, if it's way slower than that you may be building at cores = 1 or something along those lines | 06:28:07 |
| debtquity | makes sense, so then whatever I write in overrideAttrs shouldn't be pushed to nixpkgs :) | 06:28:13 |
| Charles ⚡️ | yeah | 06:28:31 |
| Charles ⚡️ | for in-nixpkgs stuff the runtime performance increase is possibly worth the build time increase since it can then be pulled by multiple users from the binary cache without having to build it themselves | 06:30:40 |
| debtquity | another thing i notice is that everytime i run nix build ./#package, it re-compiles all of the project. I thought rust had some build cache mechanism? | 06:33:36 |
| Charles ⚡️ | rust does, nix doesn't | 06:33:51 |
| debtquity | or maybe that's just the nature of nix? | 06:33:57 |
| debtquity | ooh | 06:33:59 |
| Charles ⚡️ | * rust (cargo, more accurately) does, nix doesn't | 06:34:00 |
| debtquity | so nixpkgs function would need to be improved then | 06:34:29 |
| Charles ⚡️ | nix can't do incremental builds, it can only build complete derivations | 06:34:38 |
