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PO-DEBCONF(7) po-debconf PO-DEBCONF(7)
 

NAME

po-debconf - introduction

DESCRIPTION

The goal of "debconf" was to make package configuration user-friendly. In order to achieve this, it is important to ensure that users will get the question in their own language. Translators need a framework to easily work on translations without having to track package development; "po-debconf" was designed to be able to work with standard "gettext" tools when translating debconf templates files.

ADDING I18N SUPPORT TO DEBCONF TEMPLATES FILES

If you are adding debconf support to your package, you have written a templates file containing English text. To add proper i18n support into your package, you need to:
- Create debian/po/POTFILES.in
This file contains the list of master templates. It typically contains a single line:
  [type: gettext/rfc822deb] templates
    
Paths are relative to the parent directory.
- Prepend an underscore before translatable fields in each template
Normally "Description", "Choices" and sometimes "Default" fields can be translated.
- Run debconf-updatepo
This will create the debian/po/templates.pot file that translators will translate into their language.
- Add a build dependency on "po-debconf" in debian/control

UPDATE TEMPLATES

In order to help translators, PO files in your package should always be up-to-date, otherwise they may waste their time translating unused strings. For that, simply call the following command without arguments:
  $ debconf-updatepo
You should run this command every time you change templates in English, but also when you receive new or updated translations, because translators may have worked on an obsolete PO file.
If you rename, add or remove some templates files, remember also to edit debian/po/POTFILES.in accordingly, otherwise English strings are missing from PO files and will be displayed to users even if PO files are fully translated.
The debconf-updatepo program is idempotent, it modifies PO files only if their content has been updated. Thus the best way to provide up-to-date PO files in your source package is to call this command from the "clean" target of the debian/rules file.
Please note that you need to run debconf-updatepo even if you use dh_installdebconf. The latter calls po2debconf which used to call debconf-updatepo if outdated files were detected, but this is no more the case because it was not a good solution for at least two reasons:
1.
po2debconf relied on timestamps to detect outdated files, and may be abused when using "pbuilder" or if an outdated translation has been stored on disk after templates have been modified
2.
dh_installdebconf is called long after ".diff.gz" file has been generated

MERGE TRANSLATIONS AND ORIGINAL

You have to make sure that when your package is compiled, translations will get into the built package. You can do that manually, or automatically using the dh_installdebconf script (make sure to have a versioned build dependency against "debhelper (>= 4.1.16)").
To do that manually, you'll have to merge the templates and the translations at compile time (and to have a build depend against "po-debconf") like this:
  $ po2debconf debian/templates > debian/tmp/DEBIAN/templates
BE CAREFUL: the two files called templates are not the same at all. The first one contains only the English text, with marks to denote some fields to be translated while the second contains all languages. That is to say that you CANNOT keep only the merged templates, or you won't be able to deal with translations as people submit them to you.

NEW MASTER TEMPLATES

The new templates file source format is almost identical to one of distributed templates files, but translatable fields are prepended with an underscore. Example:
  Template: debconf/frontend
  Type: select
  _Choices: Dialog, Readline, Gnome, Editor, Noninteractive
  Default: Dialog
  _Description: Interface to use for configuring packages:
   Packages that use debconf for configuration share a common look and
   feel.  You can select the type of user interface they use.
   .
   The dialog frontend is a full-screen, character based interface,
   while the readline frontend uses a more traditional plain text
   interface, and the gnome frontend is a modern X interface.  The
   editor frontend lets you configure things using your favorite text
   editor. The noninteractive frontend never asks you any questions.

SPLITTING CHOICES LIST

Since "po-debconf" 0.6.0, localized fields may contain two leading underscores. In this case, the field value is supposed to be a comma separated list of values, which are put in separate msgids. Thus if the previous example did contain
  __Choices: Dialog, Readline, Gnome, Editor, Noninteractive
there would be 5 different msgids. Note that spaces after commas are not significant.
When a choices list never changes, "_Choices" may be considered fine. However, splitting such lists may help avoiding frequent mistakes in translations such as omitting a choice or using non-standard commas. For such reasons, the use of "__Choices" will ease translator's life and is strongly recommended.
Unfortunately if you decide to switch from "_Choices" to "__Choices", all translations become fuzzy. Here is an explanation to make this change without translation loss (it requires "po-debconf" >= 1.0). Suppose that we want to switch the previous example to "__Choices". You copy the templates file into a temporary file.
  $ cp debian/templates debian/foo
Edit debian/foo and keep only "Template", "Type" and "_Choices" fields, which are in this example
  Template: debconf/frontend
  Type: select
  _Choices: Dialog, Readline, Gnome, Kde, Editor, Noninteractive
Run debconf-gettextize with "--merge" and "--choices" flags to build PO files as if "__Choices" was written, and merge these PO files to existing ones:
  $ debconf-gettextize --merge --choices debian/foo
Eventually you have to remove foo and manually edit debian/templates to replace "_Choices" by "__Choices" before debconf-updatepo is run.

PUTTING IN COMMENTS FOR TRANSLATORS

"Dpkg" maintainers decided that by convention lines beginning with a number sign ("#") are comments in debian/control files, and "po-debconf" follows this rule. Since "po-debconf" 0.8.0, such comments are written into PO files, and can then contain valuable information for translators. Incidentally all previous "po-debconf" versions ignore lines which do not contain a colon, thus if your comments does not contain any colons, there is no need to add a versioned build dependency against "po-debconf". Here is an example:
  Template: debconf/button-yes
  Type: text
  # Translators, this text will appear on a button, so KEEP IT SHORT
  _Description: Yes
Special comments have been introduced in "po-debconf" 1.0 to deal with strings which are composed of several items (as with Choices field) or paragraphs (like Description). With these directives, developers have a better control over what is exposed to translators. They are in the form "#flag: directive"; directives are detailed below.
translate:spec, translate!:spec
Mark only some items as translatable; spec is a comma separated list of numbers, it specifies which strings will be printed into PO files. Ranges can also be defined via a minus sign (for instance "2-6"), and a star ("*") means all strings. For instance, with
  Template: partman-basicfilesystems/fat_mountpoint
  Type: select
  #flag:translate:3,4
  __Choices: /dos, /windows, Enter manually, Do not mount it
  _Description: Mount point for this partition:
    
"Enter manually" and "Do not mount it" will appear in PO files but not "/dos" and "/windows". When an exclamation mark follows the translate keyword, spec specifies which strings will be discarded from PO files, all other strings are printed. Previous example is similar to
  Template: partman-basicfilesystems/fat_mountpoint
  Type: select
  #flag:translate!:1,2
  __Choices: /dos, /windows, Enter manually, Do not mount it
  _Description: Mount point for this partition:
    
The same keyword can also be applied to the Description field to make sure that some strings are not translated.
  Template: partman-crypto/options_missing
  Type: error
  #flag:translate!:3
  _Description: Required encryption options missing
   The encryption options for ${DEVICE} are incomplete. Please
   return to the partition menu and select all required options.
   .
   ${ITEMS}
    
But this is hazardous because context may be dropped from PO files, please add comments in this case so that translators are not confused.
comment:spec, comment!:spec
The comment just below this directive applies to the strings specified by spec, which is defined above. By default, a comment written before a translatable field is printed along with all strings belonging to this field. (Note: with "po-debconf" < 1.0, the comment was printed only with the first string)
  Template: arcboot-installer/prom-variables
  Type: note
  # Translators, the 4th string of this description has been dropped
  # from PO files.  It contains shell commands and should not be
  # translated.
  #flag:comment:3
  # "Stop for Maintenance" should be left in English
  #flag:translate!:4
  _Description: Setting PROM variables for Arcboot
   If this is the first Linux installation on this machine, or if the
   hard drives have been repartitioned, some variables need to be set
   in the PROM before the system is able to boot normally.
   .
   At the end of this installation stage, the system will reboot.
   After this, enter the command monitor from the "Stop for
   Maintenance" option, and enter the following commands:
   .
      setenv OSLoader arcboot
      setenv OSLoadFilename Linux
   .
   You will only need to do this once.  Afterwards, enter the "boot"
   command or reboot the system to proceed to the next stage of the
   installation.
    
The example above has a comment without "#flag:comment" directive, where an implicit "#flag:comment:*" is added. This comment appears with all strings, but the one about Stop for Maintenance is printed only before the relevant string.
partial
This keyword tells po2debconf to keep translated strings even if all strings have not been translated. Please use with caution, this keyword has been introduced for very specific purposes.

GIVING NOTICES TO TRANSLATORS BEFORE UPLOADING

Usually translators notice on the status web pages (see below) that translations are outdated, and send patches which will be included in future uploads. But developers are encouraged to ask maintainers of outdated translations for an update before an upload, for instance one week in advance. A dedicated tool, podebconf-report-po, has been written for this purpose. Do not hesitate to abuse it!

DEBUGGING

You will find that debconf-loadtemplate will not accept a templates file with i18n markups. However, it will accept a merged file, so if you have been debugging your debconf setup like this
  rm /tmp/{config,templates}.dat{,-old}
  debconf-loadtemplate debian/templates
  DEBIAN_PRIORITY=low debconf -freadline debian/config configure 28.0
you will now need something like this instead:
  po2debconf debian/templates > debian/tmp/DEBIAN/templates
  rm /tmp/{config,templates}.dat{,-old}
  debconf-loadtemplate debian/tmp/DEBIAN/templates
  DEBIAN_PRIORITY=low debconf -freadline debian/config configure 28.0

CAVEATS

"Debconf" 1.2.0 recognizes fields in the form Name-lang. encoding, e.g. "Description-de.ISO-8859-1" or "Choices-ru.KOI8-R". By default po2debconf writes templates files in that new format. Older "debconf" will ignore these fields, and English text is displayed. See po2debconf(1) to know how to change encoding and output format.
A given English string may be given only one unique translation in a given language. It is impossible to give two different translations, depending on the context. To solve this issue, you have to add special markups to the different occurrences of a given string to make them different. (These markers will only be visible to translators, and they will be removed from the string before being displayed to user)
Such markers must be added to the end of the strings to translate, they must start with "[ " (a left bracket followed by a space) and end with "]" (right bracket), and may contain any character but brackets or new lines. For example "[ blahblah]" is a valid marker while "[ bla[bla]bla]" isn't. For Perl regexp addicts, the markers are recognized (and removed) using this rule:
  $msg =~ s/\[\s[^\[\]]*\]$//s;
    
Spacing is not handled exactly the same way by "po-debconf" and "debconf-utils"; with the latter, paragraphs are reformatted when updating and merging translations, so "debconf-utils" is very smart and spaces are not considered as being part of strings when determining fuzzy entries. (i.e., the ones needing translator's attention because the original changed)
On the other hand "po-debconf" relies on "gettext" to detect fuzzy entries, and it does not treat spaces as special characters. Thus superfluous spaces must be removed at end of lines in master templates files, or they will appear in PO and POT files.
For the same reason, debconf-gettextize can mark text fuzzy because of mismatch with space characters, and translators have to manually unfuzzy such strings. This only happens once when converting templates to "po-debconf" format, unless you randomly change spaces in master templates files, which will be painful for translators.
Normally the Default: field must not be translated when template type is Select or Multiselect. Under rare circumstances (e.g. when selecting the default language for an application) localized values may be meaningful.
The localized value must not be translated, but chosen from the English values listed in the Choices field. The best way to achieve this goal is to insert a comment in your templates file which will be copied into PO files.
  Template: geneweb/lang
  Type: select
  __Choices: Danish (da), Dutch (nl), English (en), Esperanto (eo)
  #  You must NOT translate this string, but you can change its value.
  #  The comment between brackets is used to distinguish this msgid
  #  from the one in the Choices list; you do not have to worry about
  #  them, and have to simply choose a msgstr among the English values
  #  listed in the Choices field above, e.g. msgstr "Dutch (nl)"
  _Default: English (en)[ default language]
  _Description: Geneweb default language
    
The default value also appears in the Choices field, and both have different translations: the former is an untranslated value chosen among Choices values, whereas the latter is a normal translation. As "gettext" cannot have two different translations for the same msgid, both msgids must be different by using bracketed comments as described in a previous subsection.
Prior to "po-debconf" 0.8.0, such comments were not available and maintainers had to replace the _Default: field by _DefaultChoice: in order to highlight such fields in PO files:
  #. DefaultChoice
  msgid ""
  "English[ default: do not translate bracketed material, put your "
  "own language here but UNTRANSLATED.  If it is not in the list, "
  "put English (without bracketed material)]"
  msgstr ""
  "Swedish"
    
Plain comments in templates files are less error prone and are encouraged.

STATUS WEB PAGES

Statistics for "po-debconf" translations are available at <http://www.debian.org/intl/l10n/po-debconf/> (or from mirrors); they are automatically updated when new packages are uploaded. Only packages shipping debian/po/templates.pot and debian/po/POTFILES.in files are considered, so you should make sure your source package provides them.
Translators can grab PO and POT files from there, but they must always get in touch with the previous translator (her mail address can be found in the PO file) and/or their fellow translators on debian-l10n- <language>@lists.debian.org (if such a list does exist) to make sure that no one is currently working on the same translation, and read current bugreports against the package they are going to translate to see if a translation has already been reported.
After translating these files, they should submit their work to the maintainer as bug report of severity wishlist with the patch tag.

SEE ALSO

debconf-gettextize(1), debconf-updatepo(1), dh_installdebconf(1), podebconf-report-po(1), po2debconf(1), debconf-devel(7).

AUTHORS

  Martin Quinson <Martin.Quinson@ens-lyon.fr>
  Denis Barbier <barbier@linuxfr.org>
2016-10-01