Bug#594427: xdg-user-dirs: "Update standard folders" should add language links to folders, not rename them

[Papou]

Package: xdg-user-dirs
Version: 0.10-1ubuntu2
Severity: important


Limiting this explanation to French and Desktop, what xdg-user-dirs is trying to do when the user 
changes his language from English to French (and agrees) is to rename Desktop to Bureau.
For multiple reasons, see below, this is an impossible thing to do.
Instead, all these reasons disappear if a Bureau -> Desktop symbolic link is created.
And, for the same reasons, that symbolic link must be kept should the user change his language away from 
French.

The fix is simple:
- instead of renaming Desktop to Bureau, create a Bureau -> Desktop symbolic link
- instead of renaming Bureau to <any language>, do nothing
- the rest remains unchanged
unfortunately, corrective action must be taken for already polluted systems:
- corrective action, Desktop must be created and desktop data migrated to it by user

Experience:
- after filling Desktop and creating a Bureau -> Desktop symbolic link,
- xdg-user-dirs moved to French as if that fix was applied
- and the system ran flawlessly for 6 users during two years

Reasons:
They have been described in a "user experience" manner in Ubuntu bug 556933
https://bugs.launchpad.net/ubuntu/+source/xdg-user-dirs/+bug/556933

More technically:
- if any directory is renamed, its contents becomes unreachable by those having a reference to it
- hence, xdg-user-dirs quite rightly does not rename a non-empty Desktop but just creates Bureau
- in that case, the continuing user lives in a mad system (see Ubuntu's bug) until he logs in again
- and even in a new login it seems that he lost his Bureau when in fact the contents are in Desktop.

- and problems exist even if xdg-user-dirs does rename Desktop to Bureau
- many programs, scripts, people are unaware of standard folders renaming
- every time one refers to ~/Desktop, it's a mistake, and that's not only in programs...
- every time someone writes "cd ~/Desktop" in sample code on the Web, they're doing a BIG MISTAKE.
- and even worse in a script,
- they should explain that, it might well be cd "~/работая стол" !!!

-- System Information:
Debian Release: lenny/sid
  APT prefers intrepid-updates
  APT policy: (500, 'intrepid-updates'), (500, 'intrepid-security'), (500, 'intrepid-proposed'), (500, 'intrepid-backports'), (500, 'intrepid')
Architecture: i386 (i686)

Kernel: Linux 2.6.27-16-generic (SMP w/1 CPU core)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages xdg-user-dirs depends on:
ii  libc6              2.8~20080505-0ubuntu9 GNU C Library: Shared libraries

xdg-user-dirs recommends no packages.

-- no debconf information