blackbird

GC Warning: Failed to expand heap by 4194304 KiB
error:
       … while evaluating attribute 'drv'
         at /nix/store/3wxp25h4zm6vkbzljhjnj5hca89jx8zp-filnix-experiment-0.13.2/lib/experiment/planner.nix:14:3:
           13| {
           14|   drv = p.drvPath;
             |   ^
           15|   name = p.name;

       … while evaluating the attribute 'drvPath'
         at /nix/store/3h89fdpd5ri9an98yzq75irk0ccgdbzw-source/lib/customisation.nix:418:7:
          417|     // {
          418|       drvPath =
             |       ^
          419|         assert condition;

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

       error: Package ‘Blackbird-2017-12-13’ in /nix/store/3h89fdpd5ri9an98yzq75irk0ccgdbzw-source/pkgs/by-name/bl/blackbird/package.nix:25 has an unfree license (‘gpl2Plus cc-by-nc-sa-30’), refusing to evaluate.

       a) To temporarily allow unfree packages, you can use an environment variable
          for a single invocation of the nix tools.

            $ export NIXPKGS_ALLOW_UNFREE=1

          Note: When using `nix shell`, `nix build`, `nix develop`, etc with a flake,
                then pass `--impure` in order to allow use of environment variables.

       b) For `nixos-rebuild` you can set
         { nixpkgs.config.allowUnfree = true; }
       in configuration.nix to override this.

       Alternatively you can configure a predicate to allow specific packages:
         { nixpkgs.config.allowUnfreePredicate = pkg: builtins.elem (lib.getName pkg) [
             "Blackbird"
           ];
         }

       c) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
         { allowUnfree = true; }
       to ~/.config/nixpkgs/config.nix.