Make NixOS provide version-specific LOCALE_ARCHIVE environment variables

README.md

This NixOS code ensures that the system provide version-specific $LOCALE_ARCHIVE environment variables to mitigate the effects of NixOS/nixpkgs#38991.

To deploy it, copy the file into your /etc/nixos folder using a file name like multi-glibc-locale-paths.nix. Then edit your configuration.nix file to contain the attribute:

imports = [ ./multi-glibc-locale-paths.nix ];

If you are running Nix on a host system other than NixOS, you'll have to configure those environment variables manually:

• Set $LOCALE_ARCHIVE_2_27 to the path "${glibcLocales}/lib/locale/locale-archive". You can find out what glibcLocales is by running:

    $ nix-build --no-out-link "<nixpkgs>" -A glibcLocales
    /nix/store/m53mq2077pfxhqf37gdbj7fkkdc1c8hc-glibc-locales-2.27
  

• Set $LOCALE_ARCHIVE_2_11 to the path of your system's locale.

multi-glibc-locale-paths.nix

{ config, pkgs, ... }:          # multi-glibc-locale-paths.nix

/*
 * Provide version-specific LOCALE_ARCHIVE environment variables to mitigate
 * the effects of https://github.com/NixOS/nixpkgs/issues/38991.
 */

let

  # A random Nixpkgs revision *before* the default glibc
  # was switched to version 2.27.x.
  oldpkgsSrc = pkgs.fetchFromGitHub {
    owner = "nixos";
    repo = "nixpkgs";
    rev = "0252e6ca31c98182e841df494e6c9c4fb022c676";
    sha256 = "1sr5a11sb26rgs1hmlwv5bxynw2pl5w4h5ic0qv3p2ppcpmxwykz";
  };

  oldpkgs = import oldpkgsSrc {};

  # A random Nixpkgs revision *after* the default glibc
  # was switched to version 2.27.x.
  newpkgsSrc = pkgs.fetchFromGitHub {
    owner = "nixos";
    repo = "nixpkgs";
    rev = "1d0a71879dac0226272212df7a2463d8eeb8f75b";
    sha256 = "0nh6wfw50lx6wkzyiscfqg6fl6rb17wmncj8jsdvbgmsd6rm95rg";
  };

  newpkgs = import newpkgsSrc {};

in

{
  environment.sessionVariables = {
    LOCALE_ARCHIVE_2_11 = "${oldpkgs.glibcLocales}/lib/locale/locale-archive";
    LOCALE_ARCHIVE_2_27 = "${newpkgs.glibcLocales}/lib/locale/locale-archive";
  };
}

Got entirely rid of related warnings (bash: warning: setlocale: LC_CTYPE: cannot change locale (de_DE.UTF-8): No such file or directory) by editing my nix hosts (arch linux) /etc/locale.gen file accordingly and running sudo -i locale-gen. Still have the LOCALE_ARCHIVE settings applied in my nix config though not sure if they're needed in my case.