sanpo

sanpo is a command line tool to sanitize PO files from gettext for version control.

The problem

The gettext tool collects text to be translated from source code in PO files that can be sent to translators. These files contain metadata about the project that can be helpful when using an email based workflow.

When creating a PO file the first time, these metadata look like this:

"Project-Id-Version: PACKAGE VERSION\n"
"Report-Msgid-Bugs-To: \n"
"POT-Creation-Date: 2021-09-06 16:16+0200\n"
"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
"Language-Team: LANGUAGE <LL@li.org>\n"
"Language: \n"
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=UTF-8\n"
"Content-Transfer-Encoding: 8bit\n"
"Plural-Forms: nplurals=2; plural=(n != 1);\n"

However, when having the PO file under version control, these metadata get in the way. Most of them are available from the commit history. And when running gettext automatically as part of the build process, the PO-Revision-Date gets updated every time even if none of the messages changed, resulting in spuriously modified PO files without any actual changes worth committing.

The solution

Because your localized software does not use the PO files directly but the MO files compiled from them, the unhelpful metadata can be removed. Which is exactly what sanpo does.

A typical build chain would look like this:

1. gettext - collect PO file
2. msgfmt - compile into MO file
3. sanpo - remove unhelpful metadata from PO
4. commit possible changes in PO file

sanpo simple takes one or more PO files as argument, for example:

sanpo locale/de/LC_MESSAGES/django.po locale/en/LC_MESSAGES/django.po locale/hu/LC_MESSAGES/django.po

After this, the remaining metadata are:

"Language: \n"
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=UTF-8\n"
"Content-Transfer-Encoding: 8bit\n"
"Plural-Forms: nplurals=2; plural=(n != 1);\n"

Using the special pattern ** folders can be scanned recursively.

To sanitize PO files for all languages in a certain folder, use for example:

sanpo locale/**/django.po

Django

For Django projects, the typical workflow is:

1. django-admin makemessages
2. django-admin compilemessages
3. sanpo
4. commit possible changes in PO file