Why is my locale replaced when I run an external command?

Question

Why is my locale setting replaced when I run an external command with :!cmd ?

And which configurations should I check to find the cause of this problem? I've checked configs for my shell (zsh): .zshenv, .zshrc; my configs for neovim; my config for KDE. But I still don't understand why nvim seems to reset locale to en from en_GB

Within vim, running :!locale gives me this output:

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

In zsh I get:

[I] ➜ locale
LANG=en_GB.utf8
LC_CTYPE="en_GB.utf8"
LC_NUMERIC="en_GB.utf8"
LC_TIME="en_GB.utf8"
LC_COLLATE="en_GB.utf8"
LC_MONETARY="en_GB.utf8"
LC_MESSAGES="en_GB.utf8"
LC_PAPER="en_GB.utf8"
LC_NAME="en_GB.utf8"
LC_ADDRESS="en_GB.utf8"
LC_TELEPHONE="en_GB.utf8"
LC_MEASUREMENT="en_GB.utf8"
LC_IDENTIFICATION="en_GB.utf8"
LC_ALL=

UPDATE.

Inside nvim: :!echo $SHELL gets "/bin/zsh", :set shell: "shell=/bin/zsh".

In .zprofile and in .zshenv there is nothing. In .zshrc no changes to locale, LANG.

UPDATE 2

The problem is with hledger not being invoked correctly (with 'en' locale).

Answer 1

I believe Vim should not modify your current locale except for LC_NUMERIC, LC_CTYPE and possibly LC_MESSAGES. The reason being, that LC_NUMERIC is needed for handling floating point numbers and LC_CTYPE is needed for handling character classes and similar things for multibyte characters.

You can query the output of the locale inside your vim using the :lang command. The difference to using the :!locale command is, that in the later form, this will be run through another shell layer (which may or may not change the locale in the initialization scripts).

However, I believe Vim only sets LC_CTYPE and LC_NUMERIC to a default of C which should always be available on a POSIX like system. (There was once a bug, that the locale has been reset by the time the gtk/gnome libraries have been initialized, but that has been fixed long ago, and this should not apply to neovim).

LC_MESSAGES, LC_CTYPE and LC_TIME can also be set using the :lang [messages|ctype|time] value command and can be queried using the v:lang (LC_MESSAGES), v:ctype (LC_CTYPE) and v:time (LC_TIME) internal variables.

Answer 2

Vim is probably running the external program under a non-login shell, and your configuration is setting the locale correctly only for login shells.

I have no experience with zsh, but under bash it would be checking if the locale is correctly set in ~/.bash_profile and not only on ~/.bashrc.

Answer 3

Carefully read what is inside your vim configuration. It turned out I was setting let $LANG='en' in my vimrc in part I took from https://github.com/amix/vimrc/blob/master/vimrcs/basic.vim .