Wheezy locales problem - gnome-control-center region crashes with segfault

Question

In the last couple of days my locales have a serious issue. I normally am "en_GB.UTF-8". Suddenly when running apt, error messages are appearing saying

Traceback (most recent call last):
File "/usr/bin/apt-listchanges", line 33, in <module>
from ALChacks import *
File "/usr/share/apt-listchanges/ALChacks.py", line 32, in <module>
sys.stderr.write(_("Can't set locale; make sure $LC_* and $LANG are correct!\n"))
NameError: name '_' is not defined
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
LANGUAGE = (unset),
LC_ALL = (unset),
LC_TIME = "en_gb",
LC_MONETARY = "en_gb",
LC_MEASUREMENT = "en_gb",
LC_NUMERIC = "en_gb",
LANG = "en_US.utf8"
are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
Gtk-WARNING **: Locale not supported by C library.
Using the fallback 'C' locale. at /usr/share/perl5/Debconf/FrontEnd    /Gnome.pm line 97, <> line 1.

Also if I try to run "gnome-control-center region" it either segfaults or the GUI appears, but if I try to set anything, it segfaults. Notice the "en_gb"s in the error message - a lower-case "GB" is illegal. Also I don't think en_US even exists as a locale on my system. When I login a dialog asks me if I want to rename directories as "my language has changed" - a bit disturbing. I think it started after an update, but I did try to install gnome-shell 3.2 from sid (because I mistakenly believed it would be easy to fulfil its dependencies, & wanted to use gnome extensions). I rolled it back, but could that have bent something out of shape? If so what should I reinstall?

Output of /usr/bin/locale:

locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
LANG=en_US.utf8
LANGUAGE=
LC_CTYPE="en_US.utf8"
LC_NUMERIC=en_gb
LC_TIME=en_gb
LC_COLLATE="en_US.utf8"
LC_MONETARY=en_gb
LC_MESSAGES="en_US.utf8"
LC_PAPER="en_US.utf8"
LC_NAME="en_US.utf8"
LC_ADDRESS="en_US.utf8"
LC_TELEPHONE="en_US.utf8"
LC_MEASUREMENT=en_gb
LC_IDENTIFICATION="en_US.utf8"
LC_ALL=

Output of locale -a:

C
C.UTF-8
en_GB
en_GB.iso88591
en_GB.utf8
POSIX

Answer 1

Locale definitions take up a lot of disk space (if you add up all the different locales that are available), so Debian and other distributions generate them upon request. On Debian, run dpkg-reconfigure locales (as root) and select the locales you are interested in. Make sure to check the box for en_US.utf8 (and other en_US variants while you're at it). Also, some categories are strangely declared as en_gb; search for the string en_gb in your configuration files (grep -r en_gb ~/.[!.]* /etc) and fix the offending file.

Answer 2

Finally found where the "en_gb" was coming from. Ran dconf (the new gconf2-style gnome config replacement. I should've checked these settings before :-). Under system->locale, lo! & behold! there it is. I altered it to "en_GB" & restarted the Gnome session. Now the output of /usr/bin/locale is exactly as expected, no lower-case locales & no spurious en_US ones either. Not sure how the dconf stting came to be miss-set. I certainly have no memory of doing it myself & can't think why I'd want to alter it either. "gnome-control-center region" works fine now also. No segfaulting, & all seems to work OK. Bit shabby that a non-existent locale causes it to fall over, surely it wouldn't be too hard to fail more gracefully & perhaps offer up an informative message. Thanks to Gilles for his helpful suggestions - he was right about the config aspect, I don't know how I missed it. Shall have to see how dconf data is actually stored.