Using niv to version home-manager zsh plugins?

mjlbach · December 9, 2019, 4:43am

I currently have a shell configuration through home-manager which pulls specific commits from github. I’d like to automatically update these throughout my project. Currently, my config does this:

Read them by running the command 'home-manager news'.
{ config, pkgs, libs, ... }:

let sources = import ../../nix/sources.nix ;
in
{
  home = {

    packages = with pkgs; [
      zsh
      nix-zsh-completions
      bat
      exa
      fd
      fzf
      htop
      tmux
      ripgrep
      tree
      universal-ctags
      z-lua
    ];
  };

  programs.zsh = {
    enable = true;
    enableCompletion= false;
    initExtraBeforeCompInit = builtins.readFile ../../config/zsh/.zshrc ;
    plugins = [ {
      name = "powerlevel10k";
      src =  pkgs.fetchFromGitHub {
        owner = sources.powerlevel10k.owner;
        repo = sources.powerlevel10k.repo;
        rev = sources.powerlevel10k.rev;
        sha256 = sources.powerlevel10k.sha256;
       };
     }
    ];
  };
}

I’ve heard niv is the right solution from Freenode, but I’m currently unclear how to use it in my config. The above works, but I’m not sure if there is a cleaner way which could avoid using fetchFromGithub (this seems redundant since calling the niv expression should pull the source?

fzakaria · September 2, 2020, 5:43am

@mjlbach you can use outPath

For instance my niv has ohmytmux

nix-repl> sources = import ./nix/sources.nix

nix-repl> :p sources.ohmytmux.outPath        
"/nix/store/g4rqqm935w80vv4ybi8g6z1m4y2pxnlj-ohmytmux-src"

So you can probably just set src to that; in fact the variable automatically converts to a string. (Unclear what causes this in Nix)

nix-repl> :p sources.ohmytmux.outPath + "/"
"/nix/store/g4rqqm935w80vv4ybi8g6z1m4y2pxnlj-ohmytmux-src/"

danieldk · September 2, 2020, 12:16pm

Or use antiquotation. E.g.:

somepath = "${sources.mozilla}/package-set.nix"

fzakaria · September 2, 2020, 2:06pm

What part of the nix language auto coerces attrset to a string?

I can’t find it anywhere.

danieldk · September 2, 2020, 3:58pm

Good question.

github.com

NixOS/nix/blob/b721877b85bbf9f78fd2221d8eb540373ee1e889/src/libexpr/eval.cc#L1772


if (v.type == tPath) {
    Path path(canonPath(v.path));
    return copyToStore ? copyPathToStore(context, path) : path;
}

if (v.type == tAttrs) {
    auto maybeString = tryAttrsToString(pos, v, context, coerceMore, copyToStore);
    if (maybeString) {
        return *maybeString;
    }
    auto i = v.attrs->find(sOutPath);
    if (i == v.attrs->end()) throwTypeError(pos, "cannot coerce a set to a string");
    return coerceToString(pos, *i->value, context, coerceMore, copyToStore);
}

if (v.type == tExternal)
    return v.external->coerceToString(pos, context, coerceMore, copyToStore);

if (coerceMore) {

    /* Note that `false' is represented as an empty string for

nix-repl> foo = {}
nix-repl> "${foo}"
error: cannot coerce a set to a string, at (string):1:2
nix-repl> bar = { outPath = "/hello/world"; }
nix-repl> "${bar}"                            
"/hello/world"

I guess it would be nice if this was documented in the Nix manual.

fzakaria · September 2, 2020, 4:12pm

Thanks for finding the source lines; yea it seems like a pretty useful feature for coercing.
Maybe a Wiki entry or a GitHub issue to document.

I’ll see what I have time for today.