Bug#413249: severity of 413249 is important, tagging 413249

[Frank Küster <frank@kuesterei.ch>]

clone 413249 -1
retitle 413249 "wrong returnvalue logic in config script"
tags 413249 -unreproducible
retitle -1 debconf: database communication does not work
reassign -1 debconf
thanks

Frank Küster <frank@kuesterei.ch> wrote:

> It is very well reproducible here, it occurred again today.  
[...]
> The bug I found so far is

(this is going to stay 413249, package x11-common)

> while :; do
>   run db_input low x11-common/xwrapper/nice_value
>   # is the question going to be asked?
>   if [ $? -eq 30 ]; then
>     break # no; bail out of validation loop
>   fi
>
> Because db_input is wrapped in the "run" function, the return value of
> db_input is no longer in $?, and the script will not break the loop.  It
> is in $_retval, though:
>
> run () {
> [...]
>   "$@" || _retval=$?
>
>   if [ ${_retval:-0} -ne 0 ]; then
>     observe "command \"$*\" exited with status $_retval"
>   fi
>
> The patch for this would be
>
>  while :; do
>    run db_input low x11-common/xwrapper/nice_value
>    # is the question going to be asked?
> +  WILL_BE_ASKED=$_retval
> -  if [ $? -eq 30 ]; then
> +  if [ $WILL_BE_ASKED -eq 30 ]; then
>     break # no; bail out of validation loop
>   fi
>
> However, changing this doesn't fix my problem, and I got sceptical
> whether it originates in x11-common, since I get so many internal
> debconf errors.

This is why I reassign the other part of this to debconf.  I'm quite
sure that what is going on on my system is not a general breakage of
debconf, but for sure it is something that needs investigation

[work on debconf snipped, see bug log]
> debconf (developer): <-- GET x11-common/xwrapper/nice_value
> debconf (developer): --> 0 0
> + IFS='
> '
> + read -r _db_internal_line
[...]
> Why on earth is "$RET" now "value set", where it should be "0"?  Note
> that "value set" was the last answer that debconf communicated about
> that template, but not the last answer it communcated in that script
> (which was about allowed_users.

Now the debug output below adds to the confusion, but it might be easier
to debug.  I have done

# dpkg --purge --force-depends x11-common

and then installed again, with "set -xv" in the maintainer scripts.
Things to observe:

- db_set returns with exit code "1".  Is this okay?  I think it
  shouldn't, and it's a peculiarity of x11-common to not stop when this
  happens.  However, what does it indicate on the debconf side?

- after the skipped parts, the db_input part is not interesting, but
  shows that that goes without errors

- db_go gives an internal debconf error (I have just "apt-get
  --reinstall install"'ed the etch version, so the files should be okay) 

- db_get returns *nothing*, although it was set to "0" earlier.

+ run db_set x11-common/xwrapper/nice_value 0
+ '[' 3 -lt 1 ']'
+ db_set x11-common/xwrapper/nice_value 0
+ _db_cmd 'SET x11-common/xwrapper/nice_value' 0
+ IFS=' '
+ printf '%s\n' 'SET x11-common/xwrapper/nice_value 0'
debconf (developer): <-- SET x11-common/xwrapper/nice_value 0
debconf (developer): --> 0 value set
+ IFS='
'
+ read -r _db_internal_line
+ RET='value set'
+ case ${_db_internal_line%%[ 	]*} in
+ return 0
+ '[' 1 -ne 0 ']'
+ observe 'command "db_set x11-common/xwrapper/nice_value 0" exited with status 1'
+ '[' -n '' ']'

[... some parts skipped ...]

+ run db_input low x11-common/xwrapper/nice_value
+ '[' 3 -lt 1 ']'
+ db_input low x11-common/xwrapper/nice_value
+ _db_cmd 'INPUT low' x11-common/xwrapper/nice_value
+ IFS=' '
+ printf '%s\n' 'INPUT low x11-common/xwrapper/nice_value'
+ IFS='
'
+ read -r _db_internal_line
debconf (developer): <-- INPUT low x11-common/xwrapper/nice_value
debconf (developer): --> 30 question skipped
+ RET='30 question skipped'
+ case ${_db_internal_line%%[ 	]*} in
+ return 30
+ _retval=30
+ '[' 30 -ne 0 ']'
+ observe 'command "db_input low x11-common/xwrapper/nice_value" exited with status 30'
+ '[' -n '' ']'
+ '[' 0 -eq 30 ']'
+ run db_go
+ '[' 1 -lt 1 ']'
+ db_go
+ _db_cmd 'GO '
+ IFS=' '
+ printf '%s\n' 'GO '
+ IFS='
'
+ read -r _db_internal_line
debconf (developer): <-- GO 
Use of uninitialized value in join or string at /usr/share/perl5/Debconf/DbDriver/Stack.pm line 104, <GEN1> line 7.
debconf (developer): --> 0 ok
+ RET=ok
+ case ${_db_internal_line%%[ 	]*} in
+ return 0
+ '[' 30 -ne 0 ']'
+ observe 'command "db_go" exited with status 30'
+ '[' -n '' ']'
+ RET=
+ db_get x11-common/xwrapper/nice_value
+ _db_cmd 'GET x11-common/xwrapper/nice_value'
+ IFS=' '
+ printf '%s\n' 'GET x11-common/xwrapper/nice_value'
+ IFS='
'
+ read -r _db_internal_line
debconf (developer): <-- GET x11-common/xwrapper/nice_value
debconf (developer): --> 0 
+ RET=

Any idea what's going on?

Regards, Frank

-- 
Dr. Frank Küster
Single Molecule Spectroscopy, Protein Folding @ Inst. f. Biochemie, Univ. Zürich
Debian Developer (teTeX/TeXLive)