Build failure: turbo-unwrapped

[typedrat]

Nixpkgs version

• Unstable (25.11)

Steps to reproduce

1. Build turbo-unwrapped for aarch64-linux

Can Hydra reproduce this build failure?

Please select the Hydra Status.

Link to Hydra build job

https://hydra.nixos.org/build/313887779

Relevant log output

error: let chains are only allowed in Rust 2024 or later
   --> crates/turborepo-lib/src/engine/builder.rs:735:24
    |
735 |                     if let Some((span, text)) = read_req.required()
    |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: let chains are only allowed in Rust 2024 or later
   --> crates/turborepo-lib/src/turbo_json/validator.rs:101:8
    |
101 |     if let Some(package_name) = turbo_json.extends.first()
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

warning: the feature `let_chains` has been stable since 1.88.0 and no longer requires an attribute to enable
 --> crates/turborepo-lib/src/lib.rs:7:12
  |
7 | #![feature(let_chains)]
  |            ^^^^^^^^^^
  |
  = note: `#[warn(stable_features)]` on by default

warning: `turborepo-lib` (lib) generated 1 warning
error: could not compile `turborepo-lib` (lib) due to 2 previous errors; 1 warning emitted

Additional context

No response

System metadata

sh-5.3$ nix run nixpkgs#nix-info -- -m
 - system: `"aarch64-linux"`
 - host os: `Linux 6.12.57, NixOS, 25.11 (Xantusia), 25.11.20251111.9da7f1c`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Determinate Nix 3.13.1) 2.32.4`
 - nixpkgs: `/nix/store/hbmffmfg8gnp2ahfw29w1y4avzqsliyn-source`

Notify maintainers

@dlip @getchoo

---

Note for maintainers: Please tag this issue in your pull request description. (i.e. Resolves #ISSUE.)

I assert that this issue is relevant for Nixpkgs

• I assert that this is a bug and not a support request.
• I assert that this is not a duplicate of an existing issue.
• I assert that I have read the NixOS Code of Conduct and agree to abide by it.

Is this issue important to you?

Add a 👍 reaction to issues you find important.

[typedrat]

This is fixed by #457482.

Since the Modrinth breakage is already extant on nixos-unstable, can we merge this?

(More precisely, I think it's in the blast radius of the same Rust change that causes this issue, but I haven't bisected on it so I can't be sure. If someone's feeling motivated, the working commit I have pre-update is 7241bcbb4f099a66aafca120d37c65e8dda32717)

[gepbird]

To clear up the confusion: there was an experimental feature in rust called let_chains which were available in nightly (in nixpkgs using env.RUSTC_BOOTSTRAP = 1). A few weeks ago it was stabilized and got released which means it's NOT available in nightly like before and the the opting-in to the features is redundant (#![feature(let_chains)] can be removed). However it's only available if the project uses at least the 2024 rust edition. See more at: rust-lang/rust#132833.

Since the Modrinth breakage is already extant on nixos-unstable, can we merge this?

Unfortunately it needs extra changes, because that still fails on #457482.

(More precisely, I think it's in the blast radius of the same Rust change that causes this issue, but I haven't bisected on it so I can't be sure. If someone's feeling motivated, the working commit I have pre-update is 7241bcb)

Caused by #451179