"cannot change locale" warnings

[dpprdan]

I get "cannot change locale" warnings, when I build r-ver (4.1.2) images. They occur on GHA here as well:

E.g. here

/bin/bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)

and here

#10 6.729 perl: warning: Setting locale failed.
#10 6.729 perl: warning: Please check that your locale settings:
#10 6.729 	LANGUAGE = (unset),
#10 6.729 	LC_ALL = "en_US.UTF-8",
#10 6.730 	LANG = "en_US.UTF-8"
#10 6.730     are supported and installed on your system.
#10 6.730 perl: warning: Falling back to the standard locale ("C").

I can't really tell whether it succeeds in the end. I just noticed that the following code is recommended for the official Ubuntu image:

RUN apt-get update && apt-get install -y locales && rm -rf /var/lib/apt/lists/* \
	&& localedef -i en_US -c -f UTF-8 -A /usr/share/locale/locale.alias en_US.UTF-8
ENV LANG en_US.utf8

[cboettig]

Thanks @dpprdan . We do install locales and configure as such:

https://github.com/rocker-org/rocker-versioned2/blob/master/scripts/install_R.sh#L59-L61

but maybe we ought to switch to that recommended way using localedef instead?

We also set LANG, https://github.com/rocker-org/rocker-versioned2/blob/master/dockerfiles/r-ver_4.1.2.Dockerfile#L11, but maybe that needs to be utf8 instead of UTF-8? I'm not really up-to-speed on locale issues, @eddelbuettel probably knows more about this. Dirk, would you recommend we set locales as Daniel recommends above instead? Or is something else the issue here perhaps?

[eddelbuettel]

Yes, saw this issue, scratched my head, remember I have seen it too. Like you, I think it has to do with which locales are installed. and maybe something (or a value) is missing. But I do not recall what I did to nip this myself. The answer is likely tucked away in one of my containers -- if rocker/r-base does not have it, see what it does that the (similar but different) versioned2 does not.

[dpprdan]

I can't really tell whether it succeeds in the end.

I've built r-ver on GitLab and my tests confirm that the locale is set to en_US.UTF-8 in the end.

So it is just a matter of getting rid of those pesky warnings.

The r-base Dockerfile seems more or less the same as r-ver, though in somewhat different order:

https://github.com/rocker-org/rocker/blob/df1414259dceb0282f163f29f4dccfa184d38d86/r-base/4.1.2/Dockerfile#L18-L35

My hunch is that setting the ENV vars before installing the locale package in r-ver may be causing the warning.
Or maybe that the ENV vars are set both in the Dockerfile and the install_R.sh script.

[dpprdan]

Confirmed my hunch that setting the ENV vars before the locale package is available is causing the warning.
Setting ENV LANG after the install_R.sh script is run get's rid of the warnings re: locale (see this build log and this test log confirms that the locale is set.).

I am using the recommended setup (via localedef) here, which is also recommended for Debian, BTW. It is essentially identical to using local-gen as used by rocker, because, as the locale-gen manpage says:

locale-gen is a program that reads the file /etc/locale.gen and invokes localedef for the chosen localisation profiles.

Since we are only generating one locale, localedef should be sufficient, I suppose. Apparently it is also not necessary to update /etc/default/locale?!

Finally, I've also not set LC_ALL, since it is strongly discouraged e.g. in the Debian wiki.

If you want, @cboettig, I can draft a PR with these changes.

[cboettig]

@dpprdan nice, thanks! a PR on that would be great