Build your own Claude Code | Build Failure on NIXOS

Challenges
1

I’m stuck on Stage #YY2 .

I am on nixos . I am using devshell to install python and uv . then point uv to use this python. I installed codecrafters-cli from nixpkg. Issue is when i am trying to run codecrafters submit , I get below error

Here are my logs:

codecrafters-claude-code-python on  master is 📦 v0.1.0 via 🐍 v3.14.3 (codecrafters-claude-code-python) via ❄️  impure (nix-shell-env) took 28s 
λ codecrafters submit
Submitting changes (commit: 52b29e2)...

We're warming up test runners for your repository, please bear with us.
Subsequent builds will be snappy ⚡

Streaming build logs...

[build] Starting build...
[build] If you don't see logs for 60s+, please contact us at hello@codecrafters.io
[build] Step 1 complete.
[build] Step 2 complete.
[build] Step 3 complete.
[build] Step 4 complete.
[build] Step 5 complete.
[build] Step 6 complete.
[build] Step 7 complete.
[build] Step 8 complete.
[build] Step 9 complete.
[build] Step 10 complete.
[build] Step 11 complete.
[build] Step 12 complete.
[build] Step 13 complete.
[build] Step 14 complete.
[build] Error: failed to calculate checksum of ref wue8mn02yfmm39qrqsae76xl4::02c3u3nour5g7oyxp4hswntdl: "/nix/store/a453sxdh5yk3g457ds1ph3v6xf6d728g-source": not found.
[build] Build failed. Check the logs above for the reason.
[build] If you think this is a CodeCrafters error, please contact us at hello@codecrafters.io.


Looks like your codebase failed to build.
If you think this is a CodeCrafters error, please let us know at
hello@codecrafters.io.

here is my devshell that i used to download python and uv

{
  description = "A very basic flake";

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

  outputs =
    { self, nixpkgs }:
    let
      system = "x86_64-linux";
      pkgs = nixpkgs.legacyPackages.${system};
    in
    {
      devShells.${system}.default = pkgs.mkShell {

        packages = with pkgs; [
          codecrafters-cli
          nil
          nixfmt

          uv
          pyright
          ruff

          python314
        ];
        shellHook = ''
          					export UV_PYTHON_DOWNLOADS=never
                    				'';
      };
    };
}

I also have this in pyproject.toml to disable uv from managing python

[tools.uv]
python-downloads = "never"
python-preference = "only-system"

Any idea what could be the reason and how to fix it ?

2

Hi, thanks for your post!

I’m currently out of the office and will be back on March 23. I’ll get back to you as soon as possible once I return.

3

Solved it. I bymistake commited the .direnv