Hey so I just got into nix flakes and I'm trying to make the following flake:

{
  description = "A very basic flake";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
    poetry2nix.url = "github:nix-community/poetry2nix";
  };

  outputs = { nixpkgs, ... } @ inputs:
  let
    pkgs = nixpkgs.legacyPackages.aarch64-darwin;
    poetry2nix = inputs.poetry2nix.lib.mkPoetry2Nix { inherit pkgs; };
    pythonEnv = poetry2nix.mkPoetryEnv {
        python = pkgs.python311;
        projectDir = ./.;
    };
  in 
  {
      devShells.aarch64-darwin.default = pkgs.mkShell {
          packages = [ pkgs.python311 pkgs.poetry pythonEnv ];
      };
  };
}

But I am getting this error:

error:
       … while calling the 'derivationStrict' builtin
         at <nix/derivation-internal.nix>:9:12:
            8|
            9|   strict = derivationStrict drvAttrs;
             |            ^
           10|

       … while evaluating derivation 'nix-shell'
         whose name attribute is located at /nix/store/bd4fmzws6n5542khxbifbkr6nrygi232-source/pkgs/stdenv/generic/make-derivation.nix:336:7

       … while evaluating attribute 'nativeBuildInputs' of derivation 'nix-shell'
         at /nix/store/bd4fmzws6n5542khxbifbkr6nrygi232-source/pkgs/stdenv/generic/make-derivation.nix:380:7:
          379|       depsBuildBuild              = elemAt (elemAt dependencies 0) 0;
          380|       nativeBuildInputs           = elemAt (elemAt dependencies 0) 1;
             |       ^
          381|       depsBuildTarget             = elemAt (elemAt dependencies 0) 2;

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

       error: opening file '/nix/store/afbjx0hhv5q3lkv0rmcmagd3wkq1vhrr-source/poetry.lock': No such file or directory

In reply to @rpop0:matrix.org

Hey so I just got into nix flakes and I'm trying to make the following flake:

{
  description = "A very basic flake";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
    poetry2nix.url = "github:nix-community/poetry2nix";
  };

  outputs = { nixpkgs, ... } @ inputs:
  let
    pkgs = nixpkgs.legacyPackages.aarch64-darwin;
    poetry2nix = inputs.poetry2nix.lib.mkPoetry2Nix { inherit pkgs; };
    pythonEnv = poetry2nix.mkPoetryEnv {
        python = pkgs.python311;
        projectDir = ./.;
    };
  in 
  {
      devShells.aarch64-darwin.default = pkgs.mkShell {
          packages = [ pkgs.python311 pkgs.poetry pythonEnv ];
      };
  };
}

But I am getting this error:

error:
       … while calling the 'derivationStrict' builtin
         at <nix/derivation-internal.nix>:9:12:
            8|
            9|   strict = derivationStrict drvAttrs;
             |            ^
           10|

       … while evaluating derivation 'nix-shell'
         whose name attribute is located at /nix/store/bd4fmzws6n5542khxbifbkr6nrygi232-source/pkgs/stdenv/generic/make-derivation.nix:336:7

       … while evaluating attribute 'nativeBuildInputs' of derivation 'nix-shell'
         at /nix/store/bd4fmzws6n5542khxbifbkr6nrygi232-source/pkgs/stdenv/generic/make-derivation.nix:380:7:
          379|       depsBuildBuild              = elemAt (elemAt dependencies 0) 0;
          380|       nativeBuildInputs           = elemAt (elemAt dependencies 0) 1;
             |       ^
          381|       depsBuildTarget             = elemAt (elemAt dependencies 0) 2;

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

       error: opening file '/nix/store/afbjx0hhv5q3lkv0rmcmagd3wkq1vhrr-source/poetry.lock': No such file or directory

In reply to @adis:blad.is
It's probably a flake thing: Add poetry.lock to git.

In reply to @rpop0:matrix.org
What would be the alternative? nix-shell?

In reply to @rpop0:matrix.org
So just to understand, for example in a project when using a flake that would be for setting up a more general environment to be used by everyone. On the other hand, if I need something set up just for myself (Or I'm the only one interested in using nix), a nix-shell would be the better solution?

In reply to @vengmark2:matrix.org

Yep, it's definitely something to do with the wrong Python version - I see mention of Python 3.12 in pre-commit output, and both mypy and pylint complain about missing libraries which are installed in the poetry2nix package set. Also:

❯ type -a python
python is /nix/store/d6cy7nfpwjppghqg3mav9537ypl6ww82-python3-3.11.9-env/bin/python
python is /nix/store/pgb120fb7srbh418v4i2a70aq1w9dawd-python3-3.12.5/bin/python

Any idea why this could be? I don't have Python installed at the OS level:

❯ python --version
The program 'python' is currently not installed. It is provided by
several packages. You can install it by typing one of the following:

It's even easier to see the issue in this PR.

In reply to @vengmark2:matrix.org

Yep, it's definitely something to do with the wrong Python version - I see mention of Python 3.12 in pre-commit output, and both mypy and pylint complain about missing libraries which are installed in the poetry2nix package set. Also:

❯ type -a python
python is /nix/store/d6cy7nfpwjppghqg3mav9537ypl6ww82-python3-3.11.9-env/bin/python
python is /nix/store/pgb120fb7srbh418v4i2a70aq1w9dawd-python3-3.12.5/bin/python

Any idea why this could be? I don't have Python installed at the OS level:

❯ python --version
The program 'python' is currently not installed. It is provided by
several packages. You can install it by typing one of the following:

It's even easier to see the issue in this PR, which only bumps nixpkgs and sets the global repo Python to pkgs.python311.

Or even easier than that, check out master and apply this diff:

diff --git a/python.nix b/python.nix
index 2c252db..64d5494 100644
--- a/python.nix
+++ b/python.nix
@@ -1,2 +1,2 @@
 {pkgs}:
-pkgs.python3
+pkgs.python310

With the old version of nixpkgs it builds, you get both Python 3.10 and 3.11 in the resulting shell.