Make Nix precisely emulate gitignore

This goal of this project lets you include local sources in your Nix projects, while taking gitignore files into account.

Note that although this project does a good job at emulating git's behavior, it is not the same implementation!

Installation

Recommended with Niv

nix-env -iA niv -f https://github.com/nmattia/niv/tarball/master
niv init
niv add hercules-ci/gitignore

Plain Nix way

let
  gitignoreSrc = pkgs.fetchFromGitHub { 
    owner = "hercules-ci";
    repo = "gitignore";
    # put the latest commit sha of gitignore Nix library here:
    rev = "";
    # use what nix suggests in the mismatch message here:
    sha256 = "sha256:0000000000000000000000000000000000000000000000000000";
  };
  inherit (import gitignoreSrc { inherit (pkgs) lib; }) gitignoreSource;
in
  <your nix expression>

Usage

mkDerivation {
  name = "hello";
  src = gitignoreSource ./vendored/hello;
}

Features

Reads parent gitignores even if only pointed at a subdirectory
Source hashes only change when output changes
Not impacted by large or inaccessible ignored directories
Reads user git configuration; no need to bother your team with your tool config.
Also works with restrict-eval enabled (if avoiding fetchFromGitHub)
No import from derivation ("IFD")

Comparison

Feature \ Implementation	cleanSource	siers	siers recursive	icetan	Profpatsch	numtide	this project
Ignores .git	✔️	✔️	✔️	✔️	✔️	✔️	✔️
No special Nix configuration	✔️	✔️	✔️	✔️	✔️		✔️
No import from derivation	✔️	✔️		✔️	✔️	✔️	✔️
Uses subdirectory gitignores			✔️			✔️	✔️
Uses parent gitignores						✔️ ?	✔️
Uses user gitignores						✔️	✔️
Has a test suite		✔️	✔️	✔️		?	✔️
Works with `restrict-eval` / Hydra	✔️	✔️		✔️	✔️		✔️
Descends into submodule correctly		?	?	?	?	✔️ ?	? #8
Included in nixpkgs	✔️	✔️	✔️

	Legend
✔️	Supported
✔️ ?	Probably supported
	Not supported
?	Probably not supported
-	Not applicable or depends

Please open a PR if you've found another feature, determined any of the '?' or found an inaccuracy!

Contributing

This project isn't perfect (yet) so please submit test cases and fixes as pull requests. Before doing anything drastic, it's a good idea to open an issue first to discuss and optimize the approach.

Thanks

A great shoutout to @siers for writing the intial test suite and rule translation code!

duog/gitignore