lnl-overlay.nix

self: super:

{
  # Install overlay:
  # $ mkdir -p ~/.config/nixpkgs/overlays
  # $ curl https://gist.githubusercontent.com/LnL7/570349866bb69467d0caf5cb175faa74/raw/3f3d53fe8e8713ee321ee894ecf76edbcb0b3711/lnl-overlay.nix -o ~/.config/nixpkgs/overlays/lnl.nix
  userPackages = super.userPackages or {} // {

    # Example:
    hello = self.hello;
    # add more packages here...

    # Default packages:
    # cacert = self.cacert;
    # nix = self.nix;  # don't enable this on multi-user.

    nix-rebuild = super.writeScriptBin "nix-rebuild" ''
      #!${super.stdenv.shell}
      if ! command -v nix-env &>/dev/null; then
          echo "warning: nix-env was not found in PATH, add nix to userPackages" >&2
          PATH=${self.nix}/bin:$PATH
      fi
      exec nix-env -f '<nixpkgs>' -r -iA userPackages "$@"
    '';

  };
}

Thanks again, @lilyball. I should have noticed:

Here's the version I've been using lately:

self: super:

{
  userPackages = super.userPackages or {}
    // import ./packages.nix self super
    // super.lib.optionalAttrs (builtins.pathExists ./local.nix) (import ./local.nix self super)
    // {
      # Default packages for single-user; don't include this for multi-user
      inherit (self) cacert nix;
    }
    // {
      # Utilities
      nix-rebuild = super.writeShellScriptBin "nix-rebuild" ''
        set -e
        if ! command -v nix-env &>/dev/null; then
          echo "warning: nix-env was not found in PATH, add nix to userPackages" >&2
          PATH=${self.nix}/bin:$PATH
        fi
        IFS=- read -r _ oldGen _ <<<"$(readlink "$(readlink ~/.nix-profile)")"
        oldVersions=$(readlink ~/.nix-profile/package_versions || echo "/dev/null")
        nix-env -f '<nixpkgs>' -r -iA userPackages "$@"
        IFS=- read -r _ newGen _ <<<"$(readlink "$(readlink ~/.nix-profile)")"
        ${self.diffutils}/bin/diff --color -u --label "generation $oldGen" $oldVersions \
          --label "generation $newGen" ~/.nix-profile/package_versions \
          || true
      '';
      nix-what-rebuild = super.writeShellScriptBin "nix-what-rebuild" ''
        set -e
        if ! command -v nix-env &>/dev/null; then
          echo "warning: nix-env was not found in PATH, add nix to userPackages" >&2
          PATH=${self.nix}/bin:$PATH
        fi
        IFS=- read -r _ oldGen _ <<<"$(readlink "$(readlink ~/.nix-profile)")"
        oldVersions=$(readlink ~/.nix-profile/package_versions || echo "/dev/null")
        newVersions=$(nix-build --no-out-link -A userPackages.packageVersions '<nixpkgs>')
        ${self.diffutils}/bin/diff --color -u --label "generation $oldGen" "$oldVersions" \
          --label "after rebuild" "$newVersions" \
          && echo "no changes" \
          || true
      '';

      packageVersions =
        let
          collect = attrs:
            let recurse = x:
              if super.lib.isDerivation x then [x]
              else if x.recurseForDerivations or false then collect x
              else [];
            in super.lib.concatMap recurse (super.lib.attrValues attrs);
          versions = map (pkg: pkg.name) (collect self.userPackages);
          versionText = super.lib.strings.concatMapStrings (s: s+"\n") versions;
        in
        super.writeTextDir "package_versions" versionText;
  };
}

With this version my packages are stored in a sibling file called packages.nix, which looks like

self: super:
# Packages exposed as part of nixpkgs.userPackages
{
  inherit (self)
    fish tmux
    # …
    ;
}

and I can optionally add a separate local.nix that looks the same. The reason for this is I sync this overlay between machines, and this way I can exclude local.nix from the syncing in order to get per-machine customization.

Besides that, the differences between this and my previous version are the nix-what-rebuild command that prints the diff that nix-rebuild will print if I run it, and it fixes the package version tracking to handle children of userPackages being package sets (which installs the whole set if it's marked with recurseForDerivations).

@lilyball how can I use it with flakes?

@AndersonTorres What, like, pulling in packages from flakes? I honestly don’t know, I haven’t used flakes, and what I can find with some quick internet searching does not mention any way to access flakes from outside of other flakes. Which is to say, I don’t know how flakes are actually used outside of NixOS. Surely there must be some way to do this though.

How can I use packages which have a . (period) in the name, e.g. gnome3.dconf-editor?

Now I'm getting

 nix-env -f '<nixpkgs>' -r -iA userPackages
error: syntax error, unexpected '.', at /home/ppenguin/.config/nixpkgs/packages.nix:13:8

@ppenguin You’ll have to show your packages.nix (or at least line 13), because the period there isn’t in the package name, it’s just part of the attribute path.

If the period was part of the package name (like in my case I have a package named apollo-2.30.2) you have to quote the name, like nixpkgs."apollo-2.30.2"), but that’s not the case here. What you have here is just a syntax error and I can’t diagnose it without seeing the code.

@lilyball thanks for the quick reply, my packages.nix:

self: super:
# Packages exposed as part of nixpkgs.userPackages
{
  inherit (self)
        aspell
        bc
        coreutils
        gdb
        # ... 
        # gnome3.dconf-editor
        # xorg.xdpyinfo
        # xorg.xev
        # ...
    ;
}

If I don't comment out the above lines with the ., I get the mentioned error, but if I don't use the full attribute path (i.e. when I just have e.g. xev in the file), the package is not found:

$ nix-rebuild
at: (3:2) in file: /home/ppenguin/.config/nixpkgs/packages.nix

     2| # Packages exposed as part of nixpkgs.userPackages
     3| {
      |  ^
     4|   inherit (self)

attribute 'xev' missing

$  nix-env -qaP '.*xev.*' | cat
nixos.xorg.xev  xev-1.2.3

If I quote like this "xorg.xev" or like this "nixos.xorg.xev", it also gives me the attribute missing error.

I'm using the latest script you posted.

@ppenguin You can’t use dotted paths in inherit like that. You’ll have to write it like

{
  inherit (self)
        aspell
        bc
        coreutils
        gdb
    ;
  inherit (self.gnome3)
        dconf-editor
    ;
  inherit (self.xorg)
        xdpyinfo
        xev
    ;
}

@lilyball Thanks a lot, that's something I'd have figured out by myself about a few decades later 😁

does this need to be setup for every channel?

@lilyball thanks for sharing that, looks great. I'm getting an infinite recursion error when trying to use your 2020 version (The older one works fine).

nix-env -f '' -r -iA userPackages
error: infinite recursion encountered, at /home/user/.config/nixpkgs/overlays/packages.nix:4:17

Any idea what could be causing this?

@Amir-Ahmad What does your packages.nix look like?

@lilyball I was trying with this, copied from your comment https://gist.github.com/LnL7/570349866bb69467d0caf5cb175faa74#gistcomment-3372828.

self: super:
# Packages exposed as part of nixpkgs.userPackages
{
  inherit (self)
    fish tmux
    # …
    ;
}

@Amir-Ahmad Oh I think you probably put this in ~/.config/nixpkgs/overlays/ directly, yes? I suppose I should have elaborated. Your directory structure should look like

~/.config/nixpkgs/overlays/
    userPackages/
        default.nix
        packages.nix

The nested folder name (userPackages above) doesn't matter, but the two files do need to be nested in a folder, and the main file is default.nix in this folder.

What this does is it makes userPackages/default.nix to be the actual overlay, and that in turn imports ./packages.nix to construct the userPackages set. By putting both files in the top level overlays folder you instead make them two separate overlays and the packages.nix file is then trying to overwrite each package with itself, which causes infinite recursion.

@lilyball It's working now! thanks for the explanation 👍