Issue with page `src/pages/start/3.nix-develop.mdx`

[adamjsawicki]

Hey everyone - ran into a small error on the above page.

As I was working my way through, I was unable to run the command in Beyond language-specific environments:

nix develop "https://flakehub.com/f/DeterminateSystems/zero-to-nix/*#multi"

I got the following error (forgive the blind copy paste - don't have enough context yet to know what I could leave out!):

error:
       … while calling the 'derivationStrict' builtin
         at <nix/derivation-internal.nix>:34:12:
           33|
           34|   strict = derivationStrict drvAttrs;
             |            ^
           35|

       … while evaluating derivation 'nix-shell'
         whose name attribute is located at /nix/store/qkzr5clkyq7j6n43qs5ff73in6c3wacv-source/pkgs/stdenv/generic/make-derivation.nix:333:7

       … while evaluating attribute 'nativeBuildInputs' of derivation 'nix-shell'
         at /nix/store/qkzr5clkyq7j6n43qs5ff73in6c3wacv-source/pkgs/stdenv/generic/make-derivation.nix:377:7:
          376|       depsBuildBuild              = elemAt (elemAt dependencies 0) 0;
          377|       nativeBuildInputs           = elemAt (elemAt dependencies 0) 1;
             |       ^
          378|       depsBuildTarget             = elemAt (elemAt dependencies 0) 2;

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

       error: Package ‘terraform-1.8.3’ in /nix/store/qkzr5clkyq7j6n43qs5ff73in6c3wacv-source/pkgs/applications/networking/cluster/terraform/default.nix:52 has an unfree license (‘bsl11’), 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) [
             "terraform"
           ];
         }

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

Happy to send over any relevant details / system information, but the tutorial was my introduction to Nix, so followed download + setup instructions as it was presented here. Some high level sys details:

> nix --version
nix (Nix) 2.24.6

> cat /etc/os-release
PRETTY_NAME="Ubuntu 24.04.1 LTS"
NAME="Ubuntu"
VERSION_ID="24.04"
VERSION="24.04.1 LTS (Noble Numbat)"
VERSION_CODENAME=noble
ID=ubuntu
ID_LIKE=debian
...

> uname -m
x64_64

Also, I run fish shell - not sure if that makes a difference.

[dontdieych]

Same here.

NIXPKGS_ALLOW_UNFREE=1 and ~/.config/nixpkgs/config.nix does not effect too.

Asahilinux, fish shell, rebooted after install nix.

❯ nix --version
nix (Nix) 2.24.9

❯ env|rg nix
SESSION_MANAGER=local/unix:@/tmp/.ICE-unix/2201,unix/unix:/tmp/.ICE-unix/2201
NIX_PROFILES=/nix/var/nix/profiles/default /home/a/.nix-profile
NIX_SSL_CERT_FILE=/etc/ssl/certs/ca-certificates.crt
XDG_DATA_DIRS=/home/a/.local/share/flatpak/exports/share:/var/lib/flatpak/exports/share:/usr/local/share:/usr/share:/home/a/.nix-profile/share:/nix/var/nix/profiles/default/share:/nix/var/nix/profiles/default/share:/nix/var/nix/profiles/default/share
DOCKER_HOST=unix:///run/user/1000/podman/podman.sock
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
PATH=/nix/var/nix/profiles/default/bin:/home/a/.ghcup/bin:/home/a/bin:/home/a/.bun/bin:/home/a/.deno/bin:/usr/local/go/bin:/home/a/.config/emacs/bin:/home/a/.config/fish/conf.d/jq_repl_bin:/home/a/git-clone/wiwinwlh:/home/a/.cabal/bin:/home/a/.radicle/bin:/home/a/.local/bin:/home/a/.cargo/bin:/home/a/perl5/bin:/home/a/perl5/bin:/home/a/.nvm/versions/node/v22.9.0/bin:/home/a/.config/guix/current/bin:/home/a/.nix-profile/bin:/usr/lib64/ccache:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin
NIXPKGS_ALLOW_UNFREE=1

[zalom]

Same here

❯ nix --version
nix (Nix) 2.24.9

❯ echo $0
/bin/zsh

❯ sw_vers
ProductName:            macOS
ProductVersion:         15.0.1
BuildVersion:           24A348

❯ uname -m
arm64

Trace

❯ NIXPKGS_ALLOW_UNFREE=1 nix develop "https://flakehub.com/f/DeterminateSystems/zero-to-nix/*#multi" --show-trace
error:
       … while calling the 'derivationStrict' builtin
         at <nix/derivation-internal.nix>:34:12:
           33|
           34|   strict = derivationStrict drvAttrs;
             |            ^
           35|

       … while evaluating derivation 'nix-shell'
         whose name attribute is located at /nix/store/qkzr5clkyq7j6n43qs5ff73in6c3wacv-source/pkgs/stdenv/generic/make-derivation.nix:333:7

       … while evaluating attribute 'nativeBuildInputs' of derivation 'nix-shell'
         at /nix/store/qkzr5clkyq7j6n43qs5ff73in6c3wacv-source/pkgs/stdenv/generic/make-derivation.nix:377:7:
          376|       depsBuildBuild              = elemAt (elemAt dependencies 0) 0;
          377|       nativeBuildInputs           = elemAt (elemAt dependencies 0) 1;
             |       ^
          378|       depsBuildTarget             = elemAt (elemAt dependencies 0) 2;

       … in the condition of the assert statement
         at /nix/store/qkzr5clkyq7j6n43qs5ff73in6c3wacv-source/lib/customisation.nix:352:23:
          351|             drvPath = assert condition; drv.${outputName}.drvPath;
          352|             outPath = assert condition; drv.${outputName}.outPath;
             |                       ^
          353|           } //

       … while evaluating the attribute 'handled'
         at /nix/store/qkzr5clkyq7j6n43qs5ff73in6c3wacv-source/pkgs/stdenv/generic/check-meta.nix:507:7:
          506|       # or, alternatively, just output a warning message.
          507|       handled =
             |       ^
          508|         (

       … from call site
         at /nix/store/qkzr5clkyq7j6n43qs5ff73in6c3wacv-source/pkgs/stdenv/generic/check-meta.nix:511:13:
          510|           else if valid == "no" then (
          511|             handleEvalIssue { inherit meta attrs; } { inherit (validity) reason errormsg; }
             |             ^
          512|           )

       … while calling 'handleEvalIssue'
         at /nix/store/qkzr5clkyq7j6n43qs5ff73in6c3wacv-source/pkgs/stdenv/generic/check-meta.nix:269:38:
          268|
          269|   handleEvalIssue = { meta, attrs }: { reason , errormsg ? "" }:
             |                                      ^
          270|     let

       … while calling the 'throw' builtin
         at /nix/store/qkzr5clkyq7j6n43qs5ff73in6c3wacv-source/pkgs/stdenv/generic/check-meta.nix:281:8:
          280|         else throw;
          281|     in handler msg;
             |        ^
          282|

       error: Package ‘terraform-1.8.3’ in /nix/store/qkzr5clkyq7j6n43qs5ff73in6c3wacv-source/pkgs/applications/networking/cluster/terraform/defaul

       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) [
             "terraform"
           ];
         }

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

[zalom]

Hi @lucperkins, can you please check this when convenient?