Bug#318015: xserver-xorg: dies in preinst due to debconf bug

["Steinar H. Gunderson" <sgunderson@bigfoot.com>]

Package: xserver-xorg
Version: 6.8.2.dfsg.1-1
Severity: serious

After first doing "aptitude install xserver-common" and then "aptitude
install xserver-xorg" (just "aptitude dist-upgrade" wanted to remove
~300 packages, including GNOME :-) ), I got:

   xserver-xorg config warning: migrating xserver-xfree86 templates to xserver-xorg.
   Can't call method "choices" on an undefined value at
   /usr/share/perl5/Debconf/Question.pm line 85, <GEN13> line 118.

   Received signal.  Aborting xserver-xorg package config script.

Then, it installed some other packages, and tried again, giving
essentially the same error:

   xserver-xorg config warning: migrating xserver-xfree86 templates to xserver-xorg.
   Can't call method "choices" on an undefined value at
   /usr/share/perl5/Debconf/Question.pm line 85, <GEN1> line 115.

Some manual debugging with DEBCONF_DEBUG=developer revealed:

[...]
debconf (developer): <-- SET xserver-xorg/autodetect_monitor true
debconf (developer): --> 0 value set
debconf (developer): <-- FSET xserver-xorg/autodetect_monitor seen true
debconf (developer): --> 0 true
debconf (developer): <-- METAGET xserver-xfree86/config/display/modes choices
Can't call method "choices" on an undefined value at
/usr/share/perl5/Debconf/Question.pm line 85, <GEN1> line 115.

Now, this does indeed exist in debconf:

  Name: xserver-xfree86/config/display/modes
  Template: xserver-xfree86/config/display/modes
  Value: 800x600, 640x480
  Owners: xserver-xfree86

However, there are no choices there, actually... and I can't find
anything in the templates, either. I guess the problem is:

baby:~/xorg> grep -c config/display/modes /var/cache/debconf/templates.dat
0

So, the template in question is kind of half-there, since it has a _value_
but not a template. Now, debconf shouldn't _die_ on this, and that is
probably a bug (I guess I'll kick Joey when I see him later today :-) ),
for in the meantime this breaks X.org installation in these cases...

-- System Information:
Debian Release: testing/unstable
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: i386 (i686)
Shell:  /bin/sh linked to /bin/bash
Kernel: Linux 2.6.12-3-686
Locale: LANG=nb_NO.UTF-8, LC_CTYPE=nb_NO.UTF-8 (charmap=UTF-8)

-- no debconf information

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