Nix does not provide en_US.UTF-8 locale

[gpanders]

Describe the bug

There has been some prior discussion of this (see #599), but I thought it best to open a new issue rather than resurrect an old one.

I installed nix on Red Hat 7, but I am having all kinds of difficulties with locales. I have my system locale set to en_US.UTF-8, but when I use programs installed by Nix I get errors of this form:

/nix/store/68c5b0h2w2ab57sbas1b4m073ik8hlm5-bash-4.4-p23/bin/bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = (unset),
        LC_ALL = "en_US.UTF-8",
        LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").

I asked about this on IRC and the answer I got was to simply set LC_ALL to C.UTF-8. Unfortunately, RHEL 7 does not support C.UTF-8. So I'm stuck between a rock and a hard place: if I set the locale to C.UTF-8 then Nix packages work, but system packages do not. Conversely, if I use en_US.UTF-8, system packages work, but Nix packages do not.

I have installed glibc-locales and tried setting $LOCALE_ARCHIVE, but that didn't make a difference either. Interestingly, f I install the locale package from Nix and run locale -a, en_US.UTF-8 is listed. This makes me think that the en_US.UTF-8 locale is included in the locale-archive file provided by nix; however, some programs still (apparently?) look for an actual en_US.UTF-8 directory:

$ nix-shell -p perl
bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)
bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)
bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)

[nix-shell:~]$ strace -e openat perl -E '1' 2>&1 | grep locale
openat(AT_FDCWD, "/nix/store/vaf92wc23m067q9aig6zjkcnjvrg768n-glibc-2.32-46/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
openat(AT_FDCWD, "/nix/store/vaf92wc23m067q9aig6zjkcnjvrg768n-glibc-2.32-46/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 3
openat(AT_FDCWD, "/nix/store/vaf92wc23m067q9aig6zjkcnjvrg768n-glibc-2.32-46/lib/locale/en_US.UTF-8/LC_CTYPE", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/nix/store/vaf92wc23m067q9aig6zjkcnjvrg768n-glibc-2.32-46/lib/locale/en_US.utf8/LC_CTYPE", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/nix/store/vaf92wc23m067q9aig6zjkcnjvrg768n-glibc-2.32-46/lib/locale/en_US/LC_CTYPE", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/nix/store/vaf92wc23m067q9aig6zjkcnjvrg768n-glibc-2.32-46/lib/locale/en.UTF-8/LC_CTYPE", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/nix/store/vaf92wc23m067q9aig6zjkcnjvrg768n-glibc-2.32-46/lib/locale/en.utf8/LC_CTYPE", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/nix/store/vaf92wc23m067q9aig6zjkcnjvrg768n-glibc-2.32-46/lib/locale/en/LC_CTYPE", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
perl: warning: Falling back to the standard locale ("C").

The problem is that these files don't exist:

[nix-shell:~]$ ls -al /nix/store/vaf92wc23m067q9aig6zjkcnjvrg768n-glibc-2.32-46/lib/locale
total 1792
dr-xr-xr-x 2 greande greande      28 Dec 31  1969 .
dr-xr-xr-x 5 greande greande    4096 Dec 31  1969 ..
-r--r--r-- 1 greande greande 1829488 Dec 31  1969 locale-archive

I admit that I don't understand locales very well, so I'm not sure what exactly is needed from Nix here. But it would be nice if Nix was able to support the en_US.UTF-8 locale out of the box.

Steps To Reproduce

See above.

Expected behavior

No locale issues.

nix-env --version output

nix-env (Nix) 2.4pre20210503_6d2553a

[matthewbauer]

The /en_US.UTF-8/LC_CTYPE is just a fallback if the locale isn't in locale-archive. It should be harmless.

Is it possible LOCALE_ARCHIVE is not getting set correctly in your nix-shell? This work correctly for me on NixOS:

env -i NIX_PATH=$NIX_PATH nix-shell -p perl glibcLocales --run 'LC_ALL=en_US.UTF-8 perl -e echo'

Does that fail on RHEL7? Adding glibcLocales to your nix-shell will export LOCALE_ARCHIVE for you.

[gpanders]

I just tried setting LOCALE_ARCHIVE again and now it's working... I honestly have no idea what I did differently from yesterday. Thanks for your help.

[matthewbauer]

It's possible that LOCALE_ARCHIVE could mess up your RHEL7 environment too if it's exported. That is, you probably don't want LOCALE_ARCHIVE set when you run RHEL7 commands. You could try using LOCALE_ARCHIVE_2_27 which I think will just be read by Nixpkgs.

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/warning-setlocale-lc-all-cannot-change-locale-de-de-utf-8-utf-8-invalid-argument/23621/1

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/dict-offline-version/33004/6