Bug#632798: libc6: broken LANGUAGE design

[Vincent Lefevre <vincent@vinc17.net>]

Package: libc6
Version: 2.13-10
Severity: normal

The current LANGUAGE design is broken. Here an example:

ypig% locale
LANG=POSIX
LANGUAGE=
LC_CTYPE=en_US.ISO8859-1
LC_NUMERIC="POSIX"
LC_TIME=en_DK
LC_COLLATE=POSIX
LC_MONETARY="POSIX"
LC_MESSAGES=fr_FR
LC_PAPER="POSIX"
LC_NAME="POSIX"
LC_ADDRESS="POSIX"
LC_TELEPHONE="POSIX"
LC_MEASUREMENT="POSIX"
LC_IDENTIFICATION="POSIX"
LC_ALL=
ypig% cp
cp: opérande fichier manquant
Saisissez « cp --help » pour plus d'informations.
ypig% ssh localhost locale
Connected to ypig (from ::1)
LANG=POSIX
LANGUAGE=en_US:en
LC_CTYPE=en_US.ISO8859-1
LC_NUMERIC="POSIX"
LC_TIME=en_DK
LC_COLLATE=POSIX
LC_MONETARY="POSIX"
LC_MESSAGES=fr_FR
LC_PAPER="POSIX"
LC_NAME="POSIX"
LC_ADDRESS="POSIX"
LC_TELEPHONE="POSIX"
LC_MEASUREMENT="POSIX"
LC_IDENTIFICATION="POSIX"
LC_ALL=
ypig% ssh localhost cp    
Connected to ypig (from ::1)
cp: missing file operand
Try `cp --help' for more information.

The problem is that the system sets LANGUAGE in the user's back, so
that the standard user's choice (LC_MESSAGES=fr_FR) is no longer taken
into account.

The best solution would be to make the standard locale system override
LANGUAGE, which could just be used as a fallback. Said otherwise, it
is equivalent to internally prepend the current LC_MESSAGES setting
(possibly coming from LANG or LC_ALL) to the LANGUAGE value.

Alternatively the system that sets LANGUAGE could be smarter (but it's
difficult to know what the user expects, in particular if SSH doesn't
transmit LANGUAGE).

-- System Information:
Debian Release: wheezy/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (500, 'testing'), (500, 'stable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.39-2-amd64 (SMP w/8 CPU cores)
Locale: LANG=POSIX, LC_CTYPE=en_US.ISO8859-1 (charmap=ISO-8859-1)
Shell: /bin/sh linked to /bin/dash

Versions of packages libc6 depends on:
ii  libc-bin                      2.13-10    Embedded GNU C Library: Binaries
ii  libgcc1                       1:4.6.1-2  GCC support library

libc6 recommends no packages.

Versions of packages libc6 suggests:
ii  debconf [debconf-2.0]         1.5.40     Debian configuration management sy
ii  glibc-doc                     2.13-10    Embedded GNU C Library: Documentat
ii  locales                       2.13-10    Embedded GNU C Library: National L

-- debconf information:
  glibc/upgrade: true
  glibc/disable-screensaver:
  glibc/restart-failed:
* glibc/restart-services: exim4 cups cron atd apache2