Hello,
I’m using the emacs-overlay since months but every time I run sudo nixos-rebuild switch Emacs get compiled from scratch, so now I would like to try out the nix-community binary cache and save time.
Consider that I’m using Nixos 20.09 (channel nixos-20.09) and I installed Cachix declaratively putting in my configuration.nix's imports the cachix.nix file that cachix generates when I launch cachix use nix-community, however I think that this part is ok because I don’t have errors and in my log I can read things like
copying path '[...]' from 'https://nix-community.cachix.org'...
The emacs-overlay is installed putting this in my configuration.nix:
nixpkgs.overlays = with sources; [
(import emacs-overlay)
];
where
sources = {
emacs-overlay = "${builtins.fetchTarball https://github.com/nix-community/emacs-overlay/archive/master.tar.gz}";
}
Then if I put e.g. emacsGit in my environment.systemPackages when I run sudo nixos-rebuild switch I get
[...]
/nix/store/pnm2s6q1wv51cfmcasr5iykbk63qff4s-source
copying path '/nix/store/pnm2s6q1wv51cfmcasr5iykbk63qff4s-source' from 'https://nix-community.cachix.org'...
building '/nix/store/0341rymrv7fbfk2dz8msyhh5jjr2yz7m-emacs-git-20210227.0.drv'...
unpacking sources
unpacking source archive /nix/store/pnm2s6q1wv51cfmcasr5iykbk63qff4s-source
[...]
and then the build starts. I think that only the Emacs source code derivation is downloaded from the cache.
Note that I simplified my configuration, actually I’m installing Emacs as service (specifying the package I want to use) and using a custom emacsWithPackagesFromUsePackage that uses emacsPgtkGcc. However I tried excluding what I don’t think is the cause of the problem for simplicity, I still can’t get Emacs from the cache, even with the simplification used here.
If you want you can find my complete configuration here.
Thanks all.