Add docs, examples for overriding provided hooks

[domenkozar]

Something like:

nix-pre-commit-hooks.run {
  src = gitignoreSource ./.;
  hooks = ["shellcheck"];
}

[roberth]

I'd be perfectly happy to require the YAML to be JSON and DRY it with builtins.fromJSON.
(as an alternative, not everyone likes JSON)

[roberth]

Even better: generate a YAML from with builtins.toJSON. Best: use the module system.

[roberth]

If this is about download size, I wrote a thing https://github.com/roberth/nix-lazy-env

[domenkozar]

Nice! Yes, partially it's about the download size and partially it's for providing additional hooks.

[domenkozar]

This seems nice and simple: https://github.com/kampka/pre-commit-hooks

[domenkozar]

Let's leave this one open as it needs some examples in the docs.

[timokau]

For what it's worth, I came up with this config to run the black python code formatter:

let
  nix-pre-commit-hooks = import (builtins.fetchTarball "https://github.com/cachix/pre-commit-hooks.nix/tarball/master");
  pkgs = import <nixpkgs> {};
in {
  pre-commit-check = nix-pre-commit-hooks.run {
    src = ./.;
    hooks = {
      shellcheck.enable = true;
      black = {
        enable = true;
        name = "black";
        description = "Format Python files";
        entry = "${pkgs.python3.pkgs.black}/bin/black --check";
        types = ["python"];
      };
    };
  };
}

That could probably be used as an example. I'm wondering: Why do you use the module-system here? Wouldn't it be easier and more convenient to just use a list of attrsets, with some attrsets pre defined?

[domenkozar]

I'll let that @roberth answer, I was also more for simple design of attrsets and defaults.

[roberth]

With the module system you get

• type checking, improving error messages
• a framework for documentation
• configurations merging and overrides, so you can have defaults for your team for example

[domenkozar]

https://github.com/cachix/pre-commit-hooks.nix#custom-hooks is now there