`nixos-rebuild` no longer finds the Intero package for Emacs

I recently became unable to build a configuration that used to work.
It began giving me this error:

[jeff@jbb-dell:~/nix/jbb-config]$ sudo nixos-rebuild switch
unpacking 'https://github.com/nix-community/emacs-overlay/archive/master.tar.g
building Nix...
building the system configuration...
error: undefined variable 'intero' at /etc/nixos/emacs.nix:24:7
(use '--show-trace' to show detailed location information)

Searching NixOS Search - Loading... for Intero,
I find emacs26Packages.intero, which has the name emacs-intero.
I tried replacing intero with emacs-intero,
and even with emacs26Packages.intero, but it didn’t work.

I think the problem might be that I’m using Emacs 27.1.
Here’s my Emacs configuration. Here’s the top level of my configuration, which includes the following Emacs overlay:

  nixpkgs.overlays = [
    (import (builtins.fetchTarball {
      url = https://github.com/nix-community/emacs-overlay/archive/master.tar.gz;

But I’ve had that since November, and had the config rebuilding nightly throughout all of January without incident. I don’t understand the overlay (or overlays generally). I think I copied it from Jethro Kuan, creator of org-roam, as a way to make sure things were sufficiently up to date that org-roam would work.

For now I’ve just deleted it from my config.

If I want it to work again, will I have to build an Intero package for Emacs 27 Or is that a red herring, and if so, how can I restore Intero?

Intero got removed from melpa a couple of days ago:

You should be able to restore it by using an older version of the Emacs overlay.

1 Like

Aha! Thanks for that! It led me to look at the Intero repo again – I had before but I didn’t read it very well – and it pointed me to Dante, a replacement. Which installed in seconds and works like a charm :smiley: