| 20 Oct 2025 |
 Anders | I get the same macro errors as in 1.89.0 | 12:43:17 |
|  rec joined the room. | 13:07:07 |
|  @vlmutolo:matrix.org left the room. | 15:55:08 |
| Anders | Ok, they are still using nightly features. But we can still use my nix build using rust nightly. | 16:02:40 |
 K900 | No | 16:03:31 |
| K900 | We can't | 16:03:32 |
| K900 | We will not allow Rust nightlies in nixpkgs, as that's a maintenance nightmare long term | 16:03:46 |
| Anders | I mean just to compile it outside nixpkgs. It is a flake. | 16:05:29 |
| Anders | https://github.com/Anderssorby/relibc/blob/add-nix-build/flake.nix | 16:06:18 |
| K900 | Outside of nixpkgs you can do whatever you want yeah | 16:10:13 |
 hexa | curious case of cargo metadata call of a libraries build.rs erroring out due to a missing optional dependency (libz-rs-sys) when libz-sys has been chosen instead by the lockfile of the application | 20:01:24 |
| hexa | ugh, I'm rewriting that | 20:01:49 |
| hexa | * I have a curious case where a library's build.rs calls cargo metadata and fails because an optional dependency (libz-rs-sys) is missing. | 20:02:41 |
| hexa | * Servo has locked libz-sys instead, which is an alternative to libz-rs-sys and that has been correctly vendored. | 20:03:02 |
| hexa | https://github.com/NixOS/nixpkgs/pull/453957 | 20:03:22 |
| hexa | called `Result::unwrap()` on an `Err` value: CargoMetadata {
stderr: "error: no matching package found\nsearched package name: `libz-rs-sys`
perhaps you meant: libdbus-sys or libz-sys
location searched: directory source `/build/servo-0.0.1-unstable-2025-10-20-vendor` (which is replacing registry `crates-io`)
required by package `mozjs_sys v0.140.0-6 (/build/servo-0.0.1-unstable-2025-10-20-vendor/mozjs_sys-0.140.0-6)`
" }
| 20:03:32 |
| hexa | reproducer included, but I'm frankly lost again | 20:03:58 |
| hexa | preBuild = ''
pushd ../servo-*-vendor/mozjs*sys*/
cargo metadata
exit 1
'';
| 20:04:09 |
| hexa | * preBuild = ''
pushd ../servo-*-vendor/mozjs*sys*/
cargo metadata
exit 1
'';
| 20:04:11 |
 Albert Larsan | There exists the FORBIDDEN internal-only RUSTC_BOOTSTRAP=1 env var IIRC if you want to use nightly features on stable, but you shouldn't. | 20:41:25 |
| 21 Oct 2025 |
 dramforever | don't grep RUSTC_BOOTSTRAP in nixpkgs | 04:43:27 |
|  Andrew Zah set a profile picture. | 09:49:41 |
 Sandro 🐧 | A friendly reminder about https://github.com/NixOS/nixpkgs/pull/451179 | 14:38:56 |
 niklaskorz | tested two meson-based packages and they build fine | 22:04:06 |
| niklaskorz | so from my perspective there have been enough reference packages in the comments that show this is good to go as-is | 22:07:08 |
| Sandro 🐧 | nice, thank you | 22:41:13 |
| niklaskorz | let's give Alyssa Ross same more time to react but otherwise I'd merge it tomorrow | 23:03:49 |
| niklaskorz | In reply to @hexa:lossy.network
ugh, I'm rewriting that After going through the relevant Cargo.tomls in servo and mozjs I can only conclude that this is the correct behavior | 23:17:46 |
| niklaskorz | I don't have an answer yet why cargo metadata would try to fetch a dependency that's disabled by default though | 23:18:10 |
| hexa | there is --locked for cargo metadata, but mozjs doesn't lock anything | 23:20:26 |
