No coding system used for environment variables

[Göran Uddeborg]

It seems there is no coding system applied to values of environment
variables.

I'm running a system using UTF-8.  My locale is sv_SE.utf8.  And emacs
uses UTF-8 as default most of the time.  When I open a new file for
example.

I do have issues with strings coming from environment variables
though.  I first discovered this in the vm mail system, since it
misinterpreted the variable MAIL which has the value
/var/spool/mail/göran encoded in UTF-8.  (In case your mailer mangles
it, the last file name component is g ö r a n.)  But it also
causes problems in various places, for example with functions relating
to the home directory.  $HOME is /home/göran (same last component as
before).

As an example, I start emacs in my home directory, and do a few
experiments in the scratch buffer (which has a "u" for coding system
in the mode line):

    default-directory
    "/home/göran/"

Looks good.  I see my ö.

    (expand-file-name "")
    "/home/göran"

Ok too.

    (expand-file-name "~")
    "/home/g\303\266ran"

Here the octal codes for a UTF-8 encoded ö is shown instead of
the ö itself.  The source of ~ is the environment variable HOME.
But if I explicitly ask for that variable:

    (getenv "HOME")
    "/home/göran"

Here I see the ö.

Let's have a bit more fun.  Here I try to expand a FILE with my own
name:

    (expand-file-name "göran")
    "/home/göran/göran"

Looks the way I expected it.  Now the same thing, explicitly saying to
put it in the home directory:

    (expand-file-name "~/göran")
    "/home/g\xc3\xb6ran/göran"

The ö in the file name is ok.  The ö in the directory name
is strange again, only this time it is shown in hex rather than octal.

I asked about this on gnu.emacs.help first,
(http://groups.google.se/group/gnu.emacs.help/browse_thread/thread/80258d0a17e37138/75411fce63db9b2c#75411fce63db9b2c)
I was unsure if it was a bug or my lack of understanding.  But two
other posters have suggested I report it as a bug.



In GNU Emacs 22.1.1 (x86_64-redhat-linux-gnu, GTK+ Version 2.12.1)
 of 2007-11-06 on xenbuilder2.fedora.redhat.com
Windowing system distributor `The X.Org Foundation', version 11.0.70101000
configured using `configure  '--build=x86_64-redhat-linux-gnu' 
'--host=x86_64-redhat-linux-gnu' '--target=x86_64-redhat-linux-gnu' 
'--program-prefix=' '--prefix=/usr' '--exec-prefix=/usr' '--bindir=/usr/bin' 
'--sbindir=/usr/sbin' '--sysconfdir=/etc' '--datadir=/usr/share' 
'--includedir=/usr/include' '--libdir=/usr/lib64' '--libexecdir=/usr/libexec' 
'--localstatedir=/var' '--sharedstatedir=/usr/com' '--mandir=/usr/share/man' 
'--infodir=/usr/share/info' '--with-pop' '--with-sound' '--with-gtk' 
'build_alias=x86_64-redhat-linux-gnu' 'host_alias=x86_64-redhat-linux-gnu' 
'target_alias=x86_64-redhat-linux-gnu' 'CFLAGS=-DMAIL_USE_LOCKF 
-DSYSTEM_PURESIZE_EXTRA=16777216 -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 
-fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: sv_SE.utf8
  locale-coding-system: utf-8
  default-enable-multibyte-characters: t

Major mode: Fundamental

Minor modes in effect:
  which-function-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  auto-compression-mode: t
  temp-buffer-resize-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
? <return> M-< C-n C-k C-k <switch-frame> <switch-frame> 
<switch-frame> C-y <switch-frame> <next> <down> <down> 
<down> <up> <up> <up> <up> <up> <up> <up> <up> p <switch-frame> 
<switch-frame> <switch-frame> <down-mouse-2> <mouse-2> 
<backspace> C-j C-x 4 C-f . e m <tab> <return> C-s 
v m - s p o o M-< C-x C-f . v m C-g C-x C-f ~ / . v 
m <return> C-s C-g C-_ C-s v m - s p o o l - f i l 
e s C-a ; C-x C-s <help-echo> <switch-frame> <switch-frame> 
q <switch-frame> C-n C-n C-n C-n C-n C-n C-n C-n C-n 
C-n C-n C-n C-n C-n C-c C-g <switch-frame> <help-echo> 
<help-echo> C-x M q q <help-echo> C-x M n n n n n n 
n M-< C-s S E C C-a SPC <switch-frame> <help-echo> 
C-x C-f ~ / N <tab> <return> C-x c C-a C-k r p m g 
r e p SPC l h a <return> ! <help-echo> <help-echo> 
<switch-frame> <switch-frame> <help-echo> <switch-frame> 
<switch-frame> <help-echo> <switch-frame> <switch-frame> 
<switch-frame> <switch-frame> <help-echo> <switch-frame> 
d <switch-frame> <help-echo> C-u C-u C-u <f6> C-x o 
C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p 
C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p M-> 
C-x o C-x C-f <M-backspace> <M-backspace> u p d <return> 
<help-echo> <switch-frame> M-> C-p C-p C-p C-p C-p 
C-p C-p C-p C-p C-p C-p SPC n n d d d e <next> <down> 
<down> <down> <down> <down> <down> <down> <down> <down> 
<down> <down> <down> <down> <down> <down> <down> <down> 
<down> <down> <down> <down> <down> <down> <down> <down> 
<down> <down> <down> <down> <down> <left> = C-c C-c 
SPC SPC <backspace> <backspace> <down-mouse-2> <mouse-2> 
<switch-frame> <switch-frame> <switch-frame> <switch-frame> 
n <down-mouse-2> <mouse-2> s I <tab> <return> q d SPC 
<switch-frame> M-x r e p o <tab> r <tab> <return>

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