i completely forgot about all that

are you building it as part of the nixpkgs-review, or separately?

ok gonna try

ari@dell-h100-nj4-2:~/src/nixpkgs$ git fetch origin pull/460701/head:pr-460701
From https://github.com/NixOS/nixpkgs
 * [new ref]                   refs/pull/460701/head -> pr-460701
ari@dell-h100-nj4-2:~/src/nixpkgs$ git checkout pr-460701
nix buildSwitched to branch 'pr-460701'
ari@dell-h100-nj4-2:~/src/nixpkgs$ nix-build -A "python312Packages.jax" --arg config '{ cudaSupport = true; allowUnfree = true; }'

ok gonna try

ari@dell-h100-nj4-2:~/src/nixpkgs$ git fetch origin pull/460701/head:pr-460701
From https://github.com/NixOS/nixpkgs
 * [new ref]                   refs/pull/460701/head -> pr-460701
ari@dell-h100-nj4-2:~/src/nixpkgs$ git checkout pr-460701
Switched to branch 'pr-460701'
ari@dell-h100-nj4-2:~/src/nixpkgs$ nix-build -A "python312Packages.jax" --arg config '{ cudaSupport = true; allowUnfree = true; }'

Yeah, I think so. I tend to use this one-liner, to not have to use git worktrees etc.:

 nix-build https://github.com/daniel-fahey/nixpkgs/archive/fix/python3Packages.vllm.tar.gz \
--pure --arg config '{ allowUnfree = true; cudaSupport = true; }' \
--attr python312Packages.jax

I have noticed that the pytestFlags are hard-coded and aren't affected by -j/--max-jobs:

https://github.com/NixOS/nixpkgs/blob/5d2aef6a2766b8d97f520563aace1c9b7f538051/pkgs/development/python-modules/jax/default.nix#L96-L99

so you'd have to use an overlay to change it, like this:

nix-build https://github.com/daniel-fahey/nixpkgs/archive/fix/python3Packages.vllm.tar.gz --pure --arg config '{ allowUnfree = true; cudaSupport = true; }' --arg overlays '[
      (self: super: {
        python312Packages = super.python312Packages.override {
          overrides = pythonSelf: pythonSuper: {
            jax = pythonSuper.jax.overrideAttrs (oldAttrs: {
              pytestFlags = [
                "--numprocesses=2"
                "-Wignore::DeprecationWarning"
              ];
            });
          };
        };
      })
    ]' --attr python312Packages.jax

could probably do with refactoring the derivation? Gaétan Lepage (sorry for bugging you again)