In reply to @outfoxxed:outfoxxed.me
the package just uses ${libstemmer} directly, and not via a native/target dep
how is that suppposed to be handled?

Splicing can't work when packages do that.

Use targetPackages.libstemmer instead and it might work.
If you don't want to patch Nixpkgs, you can override { inherit (self.targetPackages) libstemmer; } instead.

In reply to @outfoxxed:outfoxxed.me
Since this is in the critical chain to even getting a zero package nixos install running I'd assume theres some reason everyone doesn't run into this

Have you looked at why it's in the build time closure?

Changes to other packages may have resulted in it being required where it wasn't before.
I suspect that one of the dependants in the chain can be overridden to not require it.

libstemmer = builtins.trace "${targetPackages.libstemmer} ${buildPackages.libstemmer} ${pkgs.libstemmer}" targetPackages.libstemmer;

prints 3x and only in one of them is targetPackages set correctly

trace: /nix/store/4fca7idn7b9hy41ch7kbbwi2dn96zfyq-libstemmer-2.2.0 /nix/store/4fca7idn7b9hy41ch7kbbwi2dn96zfyq-libstemmer-2.2.0 /nix/store/4fca7idn7b9hy41ch7kbbwi2dn96zfyq-libstemmer-2.2.0
trace: /nix/store/bdsm3nvxjczzyki4057bmj941wr7gjqs-libstemmer-riscv64-unknown-linux-gnu-2.2.0 /nix/store/4fca7idn7b9hy41ch7kbbwi2dn96zfyq-libstemmer-2.2.0 /nix/store/rxys7b8xsdm6zk710f4vdmsib1gsi9zv-libstemmer-2.2.0
trace: /nix/store/4fca7idn7b9hy41ch7kbbwi2dn96zfyq-libstemmer-2.2.0 /nix/store/4fca7idn7b9hy41ch7kbbwi2dn96zfyq-libstemmer-2.2.0 /nix/store/4fca7idn7b9hy41ch7kbbwi2dn96zfyq-libstemmer-2.2.0

{
  lib,
  python,
  fetchFromGitHub,
  fetchpatch2,
  buildPythonPackage,
  cython,
  setuptools,
  targetPackages,
  buildPackages,
  pkgsCross,
  pkgs,
}: let
  #inherit (targetPackages) libstemmer;
  libstemmer = builtins.trace "${targetPackages.libstemmer} ${buildPackages.libstemmer} ${pkgs.libstemmer}" targetPackages.libstemmer;#targetPackages.libstemmer;
in buildPythonPackage rec {
  pname = "pystemmer";
  version = "2.2.0.1-fix";

  src = fetchFromGitHub {
    owner = "snowballstem";
    repo = "pystemmer";
    tag = "v${version}";
    hash = "sha256-ngPx95ybgJmndpNPBwCa3BCNsozRg+dlEw+nhlIwI58=";
  };

  patches = [
    (fetchpatch2 {
      # relax cython constraint
      name = "pystemmer-relax-cython.patch";
      url = "https://github.com/snowballstem/pystemmer/commit/d3d423dc877b4f49e0ab1776f7edaff37feb6799.patch";
      hash = "sha256-9K6gy/cLFPfW82XYHVVPXUbQhf8XyB4NUi4YqNtyWcw=";
    })
  ];

  build-system = [
    cython
    setuptools
  ];

  postConfigure = let a = ''
    export PYSTEMMER_SYSTEM_LIBSTEMMER="${lib.getDev libstemmer}/include"
  ''; in builtins.trace a a;

  env.NIX_CFLAGS_COMPILE = toString [ "-I${lib.getDev libstemmer}/include" ];

  NIX_CFLAGS_LINK = [ "-L${libstemmer}/lib" ];

  pythonImportsCheck = [ "Stemmer" ];

  checkPhase = ''
    runHook preCheck
    ${python.interpreter} runtests.py
    runHook postCheck
  '';

  meta = with lib; {
    description = "Snowball stemming algorithms, for information retrieval";
    downloadPage = "https://github.com/snowballstem/pystemmer";
    homepage = "http://snowball.tartarus.org/";
    license = with licenses; [
      bsd3
      mit
    ];
    platforms = platforms.unix;
  };
}

just doesn't build at all if i try to build it directly

nix-repl> :b nixosConfigurations.jupiter.pkgs.python312Packages.pystemmer
error:
       … while evaluating the attribute 'drvPath'
         at /nix/store/isfbldda5j8j6x3nbv1zim0c0dpf90v8-source/lib/customisation.nix:418:7:
          417|     // {
          418|       drvPath =
             |       ^
          419|         assert condition;

       … while evaluating the attribute 'drvPath'
         at /nix/store/isfbldda5j8j6x3nbv1zim0c0dpf90v8-source/lib/customisation.nix:418:7:
          417|     // {
          418|       drvPath =
             |       ^
          419|         assert condition;

       … while calling the 'derivationStrict' builtin
         at <nix/derivation-internal.nix>:37:12:
           36|
           37|   strict = derivationStrict drvAttrs;
             |            ^
           38|

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: attribute 'libstemmer' missing
       at /nix/store/070hcnb78yzmrh3xg95hn6pjkyb31r21-source/pystemmer.nix:15:34:
           14|   #inherit (targetPackages) libstemmer;
           15|   libstemmer = builtins.trace "${targetPackages.libstemmer} ${buildPackages.libstemmer} ${pkgs.libstemmer}" targetPackages.libstemmer;#targetPackages.libstemmer;
             |                                  ^
           16| in buildPythonPackage rec {

nix-repl> :p nixosConfigurations.jupiter.pkgs.targetPackages
{
  __raw = true;
  recurseForDerivations = false;
  stdenv = {
    cc = «derivation /nix/store/r1mr2kx550g5n8ayc0rxlm09ijq4pbn7-gcc-wrapper-14.2.1.20250322.drv»;
  };
}

that's certainly unhelpful

I'm getting linker errors that look like this

> /nix/store/28kj37kcx5gshdk38adk4383rfcawvhj-binutils-2.44/bin/ld: /nix/store/rxys7b8xsdm6zk710f4vdmsib1gsi9zv-libstemmer-2.2.0/lib/libstemmer.a(libstemmer.o): relocation R_X86_64_32 against `.data' can not be used when making a shared object; recompile with -fPIC