In reply to @emilytrau:matrix.org
p14: i'm not sure but #exotic:nixos.org might have more active people who could help :)

In reply to @p14:matrix.org

On aarch64-linux, pkgsCross.musl64.pkgsStatic.stdenv stopped being a cache hit sometime around the 26th of May. Sha eb5cd54d0 looks to be the first commit at which it is missing on the nixos-23.05 branch, but the non cross stdenv also broke/stopped being a cache hit then by the looks of things.

Does anyone have any idea why it might have gone missing and can we bring it back… ?

I would also like to have the equivalent, but from x86 to aarch64 cross.

If there's consensus about this being useful (#cross-compiling:nixos.org I guess), I think it would be fine to have copies of that jobset, active for the currently supported stable branch(es). (I'm on build infra team; ping me to set it up.)

Though on a related note, it seemed like contents of the jobset would benefit from some redesign of content/policy.

I want to experiment with nixpkgs#pkgsStatic.stdenv.cc.cc, and to that end I'm dropping into a nix develop shell. Unfortunately, gcc has its own builder.sh, so genericBuild doesn't give me a build. And then, running the builder.sh also doesn't work.

genericBuild fails with Makefile:26: *** missing separator. Stop.
and running the builder.sh fails with unpacker appears to have produced no directories, even though it clearly does produce a gcc-12.2.0 directory.

So two questions:

1. How do I develop nixpkgs#pkgsStatic.stdenv.cc.cc?
2. How do I reproduce what nix build does, in a nix develop shell, in general? Why doesn't genericBuild or running the builder.sh work here?

As a workaround you can try staging version of it where builder.sh was removed: $ nix develop nixpkgs/staging#pkgsStatic.stdenv.cc.cc.

I think nix develop assumes that $drv.args is -e stdenv/generic/default-builder.sh and sources that. You might be able to sourcce it manually.

nix develop also uses nixpkgs#bashInteractive instead of drv's bash and does many other ad-hoc things: https://github.com/NixOS/nix/blob/master/src/nix/develop.cc#L484

https://github.com/NixOS/nixpkgs/pull/238525

This change adds a flag to update shebang paths that point to the Nix store. This is particularly useful when a cross-compiled package uses same script at compile-time and run-time, but the interpreter must be changed since hostPlatform ≠ buildPlatform.

In reply to @p14:matrix.org
I want to try and debug the lack of an $AR variable set while building a package without incurring a full rebuild. Is there a good way to turn on tracing (set -x) while all the setup scripts run for nix develop? (context: https://github.com/NixOS/nixpkgs/pull/246577#issuecomment-1672980907)