bug#27505: LC_CTYPE affects tutorial language

[Eli Zaretskii <eliz@gnu.org>]

> From: Leonard Lausen <leonard@lausen.nl>
> Date: Tue, 27 Jun 2017 23:48:41 +0900
> 
> as far as I know the environment variable LC_CTYPE applies to
> classification and conversion of characters, and to multibyte and wide
> characters. So setting it should not influence the interface language,
> correct?
> 
> However, with the following locale:
> LANG=en_US.UTF-8
> LC_CTYPE=zh_CN.UTF-8
> LC_NUMERIC="en_US.UTF-8"
> LC_TIME="en_US.UTF-8"
> LC_COLLATE=C
> LC_MONETARY="en_US.UTF-8"
> LC_MESSAGES="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"
> LC_ALL=
> 
> I find that the emacs tutorial (C-h t) is displayed in Chinese.
> 
> Is this expected behavior or a bug?

It's the intended behavior: LC_CTYPE affects the language environment
which Emacs sets up by default.  From the Emacs manual:

     Some operating systems let you specify the character-set locale you
  are using by setting the locale environment variables ‘LC_ALL’,
  ‘LC_CTYPE’, or ‘LANG’.  (If more than one of these is set, the first one
  that is nonempty specifies your locale for this purpose.)  During
  startup, Emacs looks up your character-set locale’s name in the system
  locale alias table, matches its canonical name against entries in the
  value of the variables ‘locale-charset-language-names’ and
  ‘locale-language-names’ (the former overrides the latter), and selects
  the corresponding language environment if a match is found.  It also
  adjusts the display table and terminal coding system, the locale coding
  system, the preferred coding system as needed for the locale, and—last
  but not least—the way Emacs decodes non-ASCII characters sent by your
  keyboard.

And the language environment includes a setting for the default
tutorial.