Avoiding building Julia from source when using 20.09?

[matklad]

I’d like to try 20.09 before it is officially released. However, when I do

$ sudo nix-channel --add https://nixos.org/channels/nixos-20.03 nixos
$ sudo nixos-rebuild switch --upgrade

I think I got stuck compiling Julia and llvm from source, and running Julia’s test suite, which fails. Is there any trick to use julia package from binary cache for 20.03?

[NobbZ]

Yes, you can use different channels and install different software from those.

As julia was already broken on 20.03, you need to know the exact commit it worked on anyway, and then can install a pinned version.

let
  oldPkgs = import (fetchFromGitHub { … }) {};
in
{
  environment.systemPackages = [ oldPkgs.julia ];
}

[SRGOM]

Generally:

The 0 → pro answer here:

Steps to find a commit with cached version of package

Builds are done by hydra. Hydra periodically builds most easily reachable packages from nixpkgs. When enough packages build correctly, that commit becomes the new xxx channel. Depending on the channel, the subset of required packages is different. To inspect build state for a given package, you can search it in hydra. Searching for onedrive you get plenty of job and builds corresponding to that. [image] Lets look at the nixos:trunk-combined entry because the only other nixos-related entry is …

Specifically:

julia_10_Success = fetchTarball
{
	url = https://github.com/NixOS/nixpkgs/archive/2104c8bbdb120d6c13d999a6c0fbfe4f702cb4f9.tar.gz;
	sha256 = "1f5k2v3gd73ykcwy9lhrqfh0kl31i9y8q4fdf9nmmxfqmra0m9j9";
};