STEPS TO REPRODUCE 1. on nixos, change the localization search "defaultLocale" to en_US or something different (e.g. LC_ADDRESS, LC_TIME, LC_MONETARY etc.) in /etc/nixos/configuration.nix 2. run sudo nixos-rebuild switch --upgrade 3. restart 4. run command "localectl" to confirm your new localization. 5. go to System Settings > Region & Language 6. in there, you'll see that what you did on configuration.nix did not change the localizations in Region & Language
We first look locale config in ~/.config/plasma-localerc, if the file or config entry is non-exist, we read value from enironment. Is your ~/.config/plasma-localerc different from the system-wide config, or the system-wide config does not affect the environment?
my ~/.config/plasma-localerc different from the system-wide config. my ~/.config/plasma-localerc content is [Formats] LANG=C.UTF-8 (i intentionally installed my system with this locale ) after i changed my localed in /etc/nixos/configuration.nix, if i do localectl it says: System Locale: LANG=en_US.UTF-8 LC_NUMERIC=en_US.UTF-8 LC_TIME=en_US.UTF-8 LC_MONETARY=en_US.UTF-8 LC_PAPER=en_US.UTF-8 LC_NAME=en_US.UTF-8 LC_ADDRESS=en_US.UTF-8 LC_TELEPHONE=en_US.UTF-8 LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=en_US.UTF-8 and this is what my system follows.
~/.config/plasma-localerc has higher priority than environment variables. On kde start, the value in ~/.config/plasma-localerc should override the global one.
in Region & Language, i changed Language to American English (en_US i think it is). however, my plasma-localerc content is still LANG=C.UTF-8 not en_US.UTF-8. and yes, i see n journalctl after booting it says : nixos org.kde.powerdevil.backlighthelper[1891]: Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8. Qt depends on a UTF-8 locale, and has switched to "C.UTF-8" instead. If this causes problems, reconfigure your locale. See the locale(1) manual for more information.
I think the locale does not get set in Region & Language, maybe related to https://bugs.kde.org/show_bug.cgi?id=488692 ?
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This bug has been in NEEDSINFO status with no change for at least 30 days. The bug is now closed as RESOLVED > WORKSFORME due to lack of needed information. For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging Thank you for helping us make KDE software even better for everyone!