repo-lib

Simple Nix flake library for:

• a shared development shell (mkDevShell)
• an optional release command (mkRelease)
• a starter template (template/)

Prerequisites

• Nix with flakes enabled
• direnv (recommended)

Use the template (new repo)

From your new project folder:

nix flake new myapp -t 'git+https://git.dgren.dev/eric/nix-flake-lib?ref=v2.0.1#default' --refresh

Use the library (existing repo)

Add this flake input:

inputs.devshell-lib.url = "git+https://git.dgren.dev/eric/nix-flake-lib?ref=v2.0.1";
inputs.devshell-lib.inputs.nixpkgs.follows = "nixpkgs";

Create your shell from mkDevShell:

env = devshell-lib.lib.mkDevShell {
  inherit system;
  src = ./.;
  extraPackages = [ ];
  preToolHook = "";
  tools = [ ];
  additionalHooks = { };
};

Expose it in devShells as default and run:

nix develop

Use preToolHook when a tool needs bootstrap work before the shell prints tool versions. This is useful for tools you install outside nixpkgs, as long as the hook is idempotent.

env = devshell-lib.lib.mkDevShell {
  inherit system;
  src = ./.;

  # assumes `go` is already available in PATH, for example via `extraPackages`

  preToolHook = ''
    export GOBIN="$PWD/.tools/bin"
    export PATH="$GOBIN:$PATH"

    if ! command -v golangci-lint >/dev/null 2>&1; then
      go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest
    fi
  '';

  tools = [
    { name = "golangci-lint"; bin = "golangci-lint"; versionCmd = "version"; color = "YELLOW"; }
  ];
};

Common commands

nix fmt           # format files

Optional: release command

If your flake defines:

packages.${system}.release = devshell-lib.lib.mkRelease { inherit system; };

Run releases with:

release
release patch
release beta
release minor beta
release stable
release set 1.2.3

The release script uses ./VERSION as the source of truth and creates tags like v1.2.3. When switching from stable to a prerelease channel without an explicit bump (for example, release beta), it applies a patch bump automatically (for example, 1.0.0 -> 1.0.1-beta.1).