preseeded value of "locales/locales_to_be_generated"

[andrew bezella]

hi -

i've been having some issues w/locales on a xenial system, installed
from a jessie nfsroot with fai 5.1.  my initial problem was that i'd not
been including the 'language-pack-en' but it still doesn't seem to be
working as expected.

i'd logged https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/1598326
but at one point it appeared that might be a red herring.
the locales excerpts from debconf.data ([2]) are: 
locales locales/default_environment_locale select None
locales locales/locales_to_be_generated multiselect en_US.UTF-8 UTF-8

it's unclear to me why the run of `/var/lib/dpkg/info/locales.config
reconfigure 2.23-0ubuntu3` behaves as it does.  beyond the above
"Substitution failed" error, while looking at the debug output i noticed
other confusing bits.  e.g., after finding $target/etc/locale.gen empty,
the locales.config script (via GEN_LOCALES and SELECTED_LOCALES
variables)  appears to *un*set locales/locales_to_be_generated: 
+ SELECTED_LOCALES=
+ db_set locales/locales_to_be_generated 
+ _db_cmd SET locales/locales_to_be_generated 
+ _db_internal_IFS=     

+ IFS= 
+ printf %s\n SET locales/locales_to_be_generated 
+ IFS=  

+ IFS=
 read -r _db_internal_line
debconf (developer): <-- SET locales/locales_to_be_generated 
debconf (developer): --> 0 value set
+ RET=value set
+ return 0

similarly, it seems that the script tries to substitute the
DEFAULT_LOCALES that it finds (from on-disk files) into
locales/default_environment_locale (cf. the debconf error above) without
regard to its existing value.

while investigating i did also find this unexpected bit during fai's
debconf task (full logs[1]): 
 read -r _db_internal_line
debconf (developer): <-- SUBST locales/default_environment_locale locales en_US.UTF-8
debconf (developer): --> 100 Substitution failed
+ RET=100 Substitution failed
+ return 100

but i'm guessing some of my confusion there may have to do with: 
DEBCONF_DB_OVERRIDE="File{$tmpdb readonly:true}"
and its interaction with `dpkg-reconfigure`

because despite all the above, the resultant system ends up with the
desired debconf settings: 
locales locales/locales_to_be_generated multiselect     en_US.UTF-8 UTF-8
locales locales/default_environment_locale      select  None

*however*, the on-disk /etc/locale.gen only has commented lines and
while /etc/default/locale is empty when i set "None", it is also empty
when i set locales/default_environment_locale to en_US.UTF-8 via fai's
debconf.

then there's a bit that leads me back to that bug.  on the live system,
attempting to noninteractively reconfigure locales again *un*sets
locales/locales_to_be_generated (full output [3]): 
~# debconf-show locales
* locales/locales_to_be_generated: en_US.UTF-8 UTF-8
* locales/default_environment_locale: en_US.UTF-8
~# egrep -v ^\# /etc/locale.gen 
				[intentionally blank lines]

~# cat /etc/default/locale 
#  File generated by update-locale
~# DEBIAN_FRONTEND=noninteractive /usr/sbin/dpkg-reconfigure locales
Generating locales (this might take a while)...
  en_AG.UTF-8... done
  en_AU.UTF-8... done
  en_BW.UTF-8... done
  en_CA.UTF-8... done
  en_DK.UTF-8... done
  en_GB.UTF-8... done
  en_HK.UTF-8... done
  en_IE.UTF-8... done
  en_IN.UTF-8... done
  en_NG.UTF-8... done
  en_NZ.UTF-8... done
  en_PH.UTF-8... done
  en_SG.UTF-8... done
  en_US.UTF-8... done
  en_ZA.UTF-8... done
  en_ZM.UTF-8... done
  en_ZW.UTF-8... done
Generation complete.
~# debconf-show locales
* locales/locales_to_be_generated:
* locales/default_environment_locale: en_US.UTF-8
~# egrep -v ^\# /etc/locale.gen 


~# cat /etc/default/locale 
#  File generated by update-locale
LANG=en_US.UTF-8

so at this point i believe i'm back to it being a bug of some sort in
locales's dpkg wrappings.  notably, when `/usr/sbin/dpkg-reconfigure
locales` is run *interactively* in place of the noninteractive call,
"en_US.UTF-8 UTF-8" is *not* preselected; selecting it and completing
the reconfigure results in what i would expect (full output [4]): 
~# debconf-show locales
* locales/locales_to_be_generated: en_US.UTF-8 UTF-8
* locales/default_environment_locale: en_US.UTF-8
~# egrep -v ^\# /etc/locale.gen 


~# cat /etc/default/locale 
#  File generated by update-locale
~# /usr/sbin/dpkg-reconfigure locales
Generating locales (this might take a while)...
  en_AG.UTF-8... done
  en_AU.UTF-8... done
  en_BW.UTF-8... done
  en_CA.UTF-8... done
  en_DK.UTF-8... done
  en_GB.UTF-8... done
  en_HK.UTF-8... done
  en_IE.UTF-8... done
  en_IN.UTF-8... done
  en_NG.UTF-8... done
  en_NZ.UTF-8... done
  en_PH.UTF-8... done
  en_SG.UTF-8... done
  en_US.UTF-8... done
  en_ZA.UTF-8... done
  en_ZM.UTF-8... done
  en_ZW.UTF-8... done
Generation complete.
~# debconf-show locales
* locales/default_environment_locale: en_US.UTF-8
* locales/locales_to_be_generated: en_US.UTF-8 UTF-8
~# egrep -v ^\# /etc/locale.gen 


en_US.UTF-8 UTF-8
~# cat /etc/default/locale 
#  File generated by update-locale
LANG=en_US.UTF-8

if anyone has feedback/advice/thoughts, please lmk.  otherwise i think
i'll be adding this to that bug report.

tia!

andy

1 https://www.us.archive.org/~abezella/tmp/fai-debconf+debug.log
2 https://catalogd.archive.org/~abezella/tmp/debconf.data.txt
3 https://catalogd.archive.org/~abezella/tmp/noninteractive-dpkg-reconfigure+debug.log
4 https://catalogd.archive.org/~abezella/tmp/interactive-dpkg-reconfigure+debug.log

-- 
andrew bezella <abezella at archive.org>
Internet Archive