config.languages.rust.import when dependency needs pkg-config

[devurandom]

I have a Rust dependency that needs pkg-config to build. With the Cargo.toml, devenv.nix and devenv.yaml below, I get this error (full logs below):

thread 'main' panicked at build.rs:10:47:
called `Result::unwrap()` on an `Err` value: Could not run `PKG_CONFIG_ALLOW_SYSTEM_LIBS=1 PKG_CONFIG_ALLOW_SYSTEM_CFLAGS=1 pkg-config --libs --cflags wayland-client`
The pkg-config command could not be found.

How do I teach devenv / crate2nix / nix that rust_wayland-sys-0.31.7 needs pkg-config installed?

Cargo.toml (excerpt)

[dependencies]
bevy = "0.17"

devenv.nix

{ pkgs, lib, config, ... }:
let
  myapp = config.languages.rust.import ./. {};
in
{
  languages.rust = {
    enable = true;
    mold.enable = true;
    components = [ "rustc" "cargo" "clippy" "rustfmt" "rust-analyzer" ];
  };

  packages = with pkgs; [
    pkg-config
    alsa-lib.dev
    systemd.dev
    wayland.dev
    myapp
  ];

  outputs ={
    inherit myapp;
  };

  git-hooks.hooks = {
    rustfmt.enable = true;
    clippy.enable = true;
  };

  enterShell = ''
    echo "Linking rust source for stable access"
    ln -sfn ${config.env.RUST_SRC_PATH} ${config.env.DEVENV_STATE}/rust-lib-src
  '';
}

devenv.yaml

inputs:
  crate2nix:
    url: github:nix-community/crate2nix
    inputs:
      nixpkgs:
        follows: nixpkgs
  nixpkgs:
    url: github:cachix/devenv-nixpkgs/rolling

nix log

Running phase: unpackPhase
@nix { "action": "setPhase", "phase": "unpackPhase" }
unpacking source archive /nix/store/i22ybrphbdprjl2jn693az2z9p25c4g0-wayland-sys-0.31.7.tar.gz
source root is wayland-sys-0.31.7
setting SOURCE_DATE_EPOCH to timestamp 1153704088 of file "wayland-sys-0.31.7/src/server.rs"
Running phase: patchPhase
@nix { "action": "setPhase", "phase": "patchPhase" }
Running phase: updateAutotoolsGnuConfigScriptsPhase
@nix { "action": "setPhase", "phase": "updateAutotoolsGnuConfigScriptsPhase" }
Running phase: configurePhase
@nix { "action": "setPhase", "phase": "configurePhase" }
[0;1;32mRunning [0mcd .
[0;1;32mBuilding build.rs (wayland_sys)[0m
[0;1;32mRunning [0mrustc --crate-name build_script_build build.rs --crate-type bin -C opt-level=3 -C codegen-units=1 --edition 2021 --cfg feature="client" --cfg feature="default" --cfg feature="dlib" --cfg feature="log" --out-dir target/build/wayland-sys --emit=dep-info,link -L dependency=target/buildDeps --extern pkg_config=/nix/store/qqgi6qm5s435hvfv62wx9h5pw1k7b9sm-rust_pkg-config-0.3.32-lib/lib/libpkg_config-a43828a6b1.rlib --cap-lints allow --color always

thread 'main' panicked at build.rs:10:47:
called `Result::unwrap()` on an `Err` value: Could not run `PKG_CONFIG_ALLOW_SYSTEM_LIBS=1 PKG_CONFIG_ALLOW_SYSTEM_CFLAGS=1 pkg-config --libs --cflags wayland-client`
The pkg-config command could not be found.

Most likely, you need to install a pkg-config package for your OS.
Try `apt install pkg-config`, or `yum install pkg-config`, or `brew install pkgconf`
or `pkg install pkg-config`, or `apk add pkgconfig` depending on your distribution.

If you've already installed it, ensure the pkg-config command is one of the
directories in the PATH environment variable.

If you did not expect this build to link to a pre-installed system library,
then check documentation of the wayland-sys crate for an option to
build the library from source, or disable features or dependencies
that require pkg-config.
stack backtrace:
cargo:rerun-if-env-changed=WAYLAND_CLIENT_NO_PKG_CONFIG
cargo:rerun-if-env-changed=PKG_CONFIG_x86_64-unknown-linux-gnu
cargo:rerun-if-env-changed=PKG_CONFIG_x86_64_unknown_linux_gnu
cargo:rerun-if-env-changed=HOST_PKG_CONFIG
cargo:rerun-if-env-changed=PKG_CONFIG
cargo:rerun-if-env-changed=WAYLAND_CLIENT_STATIC
cargo:rerun-if-env-changed=WAYLAND_CLIENT_DYNAMIC
cargo:rerun-if-env-changed=PKG_CONFIG_ALL_STATIC
cargo:rerun-if-env-changed=PKG_CONFIG_ALL_DYNAMIC
cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64-unknown-linux-gnu
cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64_unknown_linux_gnu
cargo:rerun-if-env-changed=HOST_PKG_CONFIG_PATH
cargo:rerun-if-env-changed=PKG_CONFIG_PATH
cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64-unknown-linux-gnu
cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64_unknown_linux_gnu
cargo:rerun-if-env-changed=HOST_PKG_CONFIG_LIBDIR
cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR
cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64-unknown-linux-gnu
cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64_unknown_linux_gnu
cargo:rerun-if-env-changed=HOST_PKG_CONFIG_SYSROOT_DIR
cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR
cargo:rerun-if-env-changed=WAYLAND_CLIENT_STATIC
cargo:rerun-if-env-changed=WAYLAND_CLIENT_DYNAMIC
cargo:rerun-if-env-changed=PKG_CONFIG_ALL_STATIC
cargo:rerun-if-env-changed=PKG_CONFIG_ALL_DYNAMIC
cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64-unknown-linux-gnu
cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64_unknown_linux_gnu
cargo:rerun-if-env-changed=HOST_PKG_CONFIG_PATH
cargo:rerun-if-env-changed=PKG_CONFIG_PATH
cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64-unknown-linux-gnu
cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64_unknown_linux_gnu
cargo:rerun-if-env-changed=HOST_PKG_CONFIG_LIBDIR
cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR
cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64-unknown-linux-gnu
cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64_unknown_linux_gnu
cargo:rerun-if-env-changed=HOST_PKG_CONFIG_SYSROOT_DIR
cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR
   0: __rustc::rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::result::unwrap_failed
   3: build_script_build::main
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

[domenkozar]

We should allow telling the import to override some thing like adding tools.

Ideally, we'd offer a way to specify these in Cargo.toml and then keep a central registry for packages that don't specify it in Cargo.toml.

[devurandom]

We should allow telling the import to override some thing like adding tools.

You mean putting something like the following in devenv.nix?

{ pkgs, lib, config, ... }:
let
  myapp = config.languages.rust.import ./. {
    extraPackages = [
      pkgs.pkg-config
    ];
  };
in
{
  ...
}

That'd get the job done for me and I'd be OK figuring out the list of packages on my own based on the software I'm trying to build.

[domenkozar]

Yeah something like this should work, we need to figure out the correct interface here.