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terlar/dev-flake

Nix flake to support the pattern of using a separate development flake
Source code at GitHub null
terlar/dev-flake.json
{
  "createdAt": "2023-07-07T06:01:03Z",
  "defaultBranch": "main",
  "description": "Nix flake to support the pattern of using a separate development flake",
  "fullName": "terlar/dev-flake",
  "homepage": null,
  "language": "Nix",
  "name": "dev-flake",
  "pushedAt": "2025-11-20T16:48:41Z",
  "stargazersCount": 10,
  "topics": [],
  "updatedAt": "2025-11-03T08:32:52Z",
  "url": "https://github.com/terlar/dev-flake"
}

dev-flake

Section titled “dev-flake”

Nix flake to support the pattern of using a separate development sub-flake. dev-flake can also be used within the root flake. The integration is done via flake-parts.

Features

Section titled “Features”

Features are enabled by default in order to get “the best experience out of the box”, however it is possible to opt-out from the default configuration and/or add additional configuration. See available configuration options in the [flake module interface]!(flake-module/interface.nix) and the corresponding documentation for each dependency flake module.

Dependency flake modules:

Default devShell

Section titled “Default devShell”

The default devShell is provided via devshell.

  • Installs pre-commit hooks.
  • Menu with available commands.
  • Named shell prompt
  • Can be used together with direnv for seamless shell integration.
    • See the example [subflake-project template]!(template/subflake-project).

treefmt

Section titled “treefmt”

treefmt is a nice abstraction on top of formatters to format the whole project.

To configure more formatters, see the treefmt-nix documentation.

pre-commit hooks

Section titled “pre-commit hooks”

pre-commit is a framework to configure and run git hooks before commit. Usually formatting and linting.

  • Configures flake check to run pre-commit hooks
  • Enables hooks for:
    • deadnix
    • statix
    • treefmt

To configure more pre-commit hooks, see the git-hooks-nix documentation.

Usage

Section titled “Usage”

Subflake

Section titled “Subflake”

To avoid polluting the top-level flake inputs with development inputs, dev-flake can be used in a subflake.

Existing project

Section titled “Existing project”

Within an existing project ([template]!(template/subflake)):

Terminal window
mkdir -p dev
cd dev
nix flake init -t github:terlar/dev-flake

Add the following to your flake-parts config:

# ...
imports = [ inputs.flake-parts.flakeModules.partitions ];


partitionedAttrs = {
  checks = "dev";
  devShells = "dev";
};


partitions.dev = {
  extraInputsFlake = ./dev;
  module = { imports = [ ./dev/flake-module.nix ]; };
};
# ...

New project

Section titled “New project”

Create a new project ([template]!(template/subflake-project)):

Terminal window
mkdir -p project
nix flake init -t github:terlar/dev-flake#subflake-project

Subflake (with nixpkgs)

Section titled “Subflake (with nixpkgs)”

If you are creating a flake-parts library or some other flake that only produce system outputs for development purposes, you do not need to include nixpkgs within the main flake.

Existing project

Section titled “Existing project”

Within an existing project ([template]!(template/subflake-nixpkgs)):

Terminal window
mkdir -p dev
cd dev
nix flake init -t github:terlar/dev-flake#subflake-nixpkgs

Add the following to your flake-parts config:

# ...
imports = [ inputs.flake-parts.flakeModules.partitions ];


systems = [ ];


partitionedAttrs = {
  checks = "dev";
  devShells = "dev";
};


partitions.dev = {
  extraInputsFlake = ./dev;
  module = { imports = [ ./dev/flake-module.nix ]; };
};
# ...

New project

Section titled “New project”

Create a new project ([template]!(template/subflake-nixpkgs-project)):

Terminal window
mkdir -p project
nix flake init -t github:terlar/dev-flake#subflake-nixpkgs-project

Root flake

Section titled “Root flake”

You can also use this flake in the root flake, when using flake-parts, all you need to do is import the flake.

{
  inputs = {
    flake-parts.url = "github:hercules-ci/flake-parts";
    dev-flake.url = "github:terlar/dev-flake";
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
  };


  outputs = inputs:
    inputs.flake-parts.lib.mkFlake { inherit inputs; } {
      systems = [ "aarch64-darwin" "aarch64-linux" "x86_64-darwin" "x86_64-linux" ];
      imports = [ inputs.dev-flake.flakeModule ];
      dev.name = "my-project";
    };
}

Within an existing project ([template]!(template/root)):

Terminal window
mkdir -p dev
cd dev
nix flake init -t github:terlar/dev-flake#root

Create a new project ([template]!(template/root-project)):

Terminal window
mkdir -p project
nix flake init -t github:terlar/dev-flake#root-project

Examples

Section titled “Examples”