python-peps/peps/pep-0545.rst

PEP: 545
Title: Python Documentation Translations
Author: Julien Palard <julien@palard.fr>,
        Inada Naoki <songofacandy@gmail.com>,
        Victor Stinner <vstinner@python.org>
Status: Final
Type: Process
Content-Type: text/x-rst
Created: 04-Mar-2017
Resolution: https://mail.python.org/pipermail/python-dev/2017-May/147957.html


Abstract
========

The intent of this PEP is to make existing translations of the Python
Documentation more accessible and discoverable.  By doing so, we hope
to attract and motivate new translators and new translations.

Translated documentation will be hosted on python.org.  Examples of
two active translation teams:

* http://docs.python.org/fr/: French
* http://docs.python.org/ja/: Japanese

http://docs.python.org/en/ will redirect to http://docs.python.org/.

Sources of translated documentation will be hosted in the Python
organization on GitHub: https://github.com/python/.  Contributors will
have to accept a Documentation Contribution Agreement.


Motivation
==========

On the French ``#python-fr`` IRC channel on freenode, it's not rare to
meet people who don't speak English and so are unable to read the
Python official documentation.  Python wants to be widely available
to all users in any language: this is also why Python 3 supports
any non-ASCII identifiers:
:pep:`3131#rationale`

There are at least 4 groups of people who are translating the Python
documentation to their native language (French [16]_ [17]_ [18]_,
Japanese [19]_ [20]_, Spanish [21]_, Hungarian [26]_ [27]_) even
though their translations are not visible on d.p.o.  Other, less
visible and less organized groups, are also translating the
documentation, we've heard of Russian [25]_, Chinese and
Korean. Others we haven't found yet might also exist.  This PEP
defines rules describing how to move translations on docs.python.org
so they can easily be found by developers, newcomers and potential
translators.

The Japanese team has (as of March 2017) translated ~80% of the
documentation, the French team ~20%.  French translation went from 6%
to 23% in 2016 [13]_ with 7 contributors [14]_, proving a translation
team can be faster than the rate the documentation mutates.


Quoting Xiang Zhang about Chinese translations:

  I have seen several groups trying to translate part of our official
  doc.  But their efforts are disperse and quickly become lost because
  they are not organized to work towards a single common result and
  their results are hold anywhere on the Web and hard to find.  An
  official one could help ease the pain.


Rationale
=========

Translation
-----------

Issue tracker
'''''''''''''

Considering that issues opened about translations may be written in
the translation language, which can be considered noise but at least
is inconsistent, issues should be placed outside `bugs.python.org
<https://bugs.python.org/>`_ (b.p.o).

As all translation must have their own GitHub project (see `Repository
for Po Files`_), they must use the associated GitHub issue tracker.

Considering the noise induced by translation issues redacted in any
languages which may beyond every warnings land in b.p.o, triage will
have to be done.  Considering that translations already exist and are
not actually a source of noise in b.p.o, an unmanageable amount of
work is not to be expected.  Considering that Xiang Zhang and Victor
Stinner are already triaging, and Julien Palard is willing to help on
this task, noise on b.p.o is not to be expected.

Also, language team coordinators (see `Language Team`_) should help
with triaging b.p.o by properly indicating, in the language of the
issue author if required, the right issue tracker.


Branches
''''''''

Translation teams should focus on last stable versions, and use tools
(scripts, translation memory, …) to automatically translate what is
done in one branch to other branches.

.. note::
   Translation memories are a kind of database of previously translated
   paragraphs, even removed ones.  See also `Sphinx Internationalization
   <http://www.sphinx-doc.org/en/stable/intl.html>`_.

The three currently stable branches that will be translated are [12]_:
2.7, 3.5, and 3.6.  The scripts to build the documentation of older
branches needs to be modified to support translation [12]_, whereas
these branches now only accept security-only fixes.

The development branch (main) should have a lower translation priority
than stable branches.  But docsbuild-scripts should build it anyway so
it is possible for a team to work on it to be ready for the next
release.


Hosting
-------

Domain Name, Content negotiation and URL
''''''''''''''''''''''''''''''''''''''''

Different translations can be identified by changing one of the
following: Country Code Top Level Domain (CCTLD),
path segment, subdomain or content negotiation.

Buying a CCTLD for each translations is expensive, time-consuming, and
sometimes almost impossible when already registered, this solution
should be avoided.

Using subdomains like "es.docs.python.org" or "docs.es.python.org" is
possible but confusing ("is it ``es.docs.python.org`` or
``docs.es.python.org``?").  Hyphens in subdomains like
``pt-br.doc.python.org`` is uncommon and SEOMoz [23]_ correlated the
presence of hyphens as a negative factor.  Usage of underscores in
subdomain is prohibited by the :rfc:`1123`, section 2.1.  Finally,
using subdomains means creating TLS certificates for each
language. This not only requires more maintenance but will also cause
issues in language switcher if, as for version switcher, we want a
preflight to check if the translation exists in the given version:
preflight will probably be blocked by same-origin-policy.  Wildcard
TLS certificates are very expensive.

Using content negotiation (HTTP headers ``Accept-Language`` in the
request and ``Vary: Accept-Language``) leads to a bad user experience
where they can't easily change the language.  According to Mozilla:
"This header is a hint to be used when the server has no way of
determining the language via another way, like a specific URL, that is
controlled by an explicit user decision." [24]_.  As we want to be
able to easily change the language, we should not use the content
negotiation as a main language determination, so we need something
else.

Last solution is to use the URL path, which looks readable, allows
for an easy switch from a language to another, and nicely accepts
hyphens.  Typically something like: "docs.python.org/de/" or, by
using a hyphen: "docs.python.org/pt-BR/".

As for the version, sphinx-doc does not support compiling for multiple
languages, so we'll have full builds rooted under a path, exactly like
we're already doing with versions.

So we can have "docs.python.org/de/3.6/" or
"docs.python.org/3.6/de/".  A question that arises is:
"Does the language contain multiple versions or does the version contain
multiple languages?".  As versions exist in any case and translations
for a given version may or may not exist, we may prefer
"docs.python.org/3.6/de/", but doing so scatters languages everywhere.
Having "/de/3.6/" is clearer, meaning: "everything under /de/ is written
in German".  Having the version at the end is also a habit taken by
readers of the documentation: they like to easily change the version
by changing the end of the path.

So we should use the following pattern:
"docs.python.org/LANGUAGE_TAG/VERSION/".

The current documentation is not moved to "/en/", instead
"docs.python.org/en/" will redirect to "docs.python.org".


Language Tag
''''''''''''

A common notation for language tags is the :rfc:`IETF Language Tag <5646>`
[4]_ based on ISO 639, although gettext uses ISO 639 tags with
underscores (ex: ``pt_BR``) instead of dashes to join tags [5]_
(ex: ``pt-BR``).  Examples of IETF Language Tags: ``fr`` (French),
``ja`` (Japanese), ``pt-BR`` (Orthographic formulation of 1943 -
Official in Brazil).

It is more common to see dashes instead of underscores in URLs [6]_,
so we should use IETF language tags, even if sphinx uses gettext
internally: URLs are not meant to leak the underlying implementation.

It's uncommon to see capitalized letters in URLs, and docs.python.org
doesn't use any, so it may hurt readability by attracting the eye on it,
like in: "https://docs.python.org/pt-BR/3.6/library/stdtypes.html".
:rfc:`5646#section-2.1.1`
(Tags for Identifying Languages (IETF)) section-2.1
states that tags are not case sensitive.  As the RFC allows lower case,
and it enhances readability, we should use lowercased tags like
``pt-br``.

We may drop the region subtag when it does not add distinguishing
information, for example: "de-DE" or "fr-FR". (Although it might
make sense, respectively meaning "German as spoken in Germany"
and "French as spoken in France"). But when the region subtag
actually adds information, for example "pt-BR" or "Portuguese as
spoken in Brazil", it should be kept.

So we should use IETF language tags, lowercased, like ``/fr/``,
``/pt-br/``, ``/de/`` and so on.


Fetching And Building Translations
''''''''''''''''''''''''''''''''''

Currently docsbuild-scripts are building the documentation [8]_.
These scripts should be modified to fetch and build translations.

Building new translations is like building new versions so, while we're
adding complexity it is not that much.

Two steps should be configurable distinctively: Building a new language,
and adding it to the language switcher.  This allows a transition step
between "we accepted the language" and "it is translated enough to be
made public".  During this step, translators can review their
modifications on d.p.o without having to build the documentation
locally.

From the translation repositories, only the ``.po`` files should be
opened by the docsbuild-script to keep the attack surface and probable
bug sources at a minimum.  This means no translation can patch sphinx
to advertise their translation tool.  (This specific feature should be
handled by sphinx anyway [9]_).


Community
---------

Mailing List
''''''''''''

The `doc-sig`_ mailing list will be used to discuss cross-language
changes on translated documentation.

There is also the i18n-sig list but it's more oriented towards i18n APIs
[1]_ than translating the Python documentation.

.. _i18n-sig: https://mail.python.org/mailman/listinfo/i18n-sig
.. _doc-sig: https://mail.python.org/mailman/listinfo/doc-sig


Chat
''''

Due to the Python community being highly active on IRC, we should
create a new IRC channel on freenode, typically #python-doc for
consistency with the mailing list name.

Each language coordinator can organize their own team, even by choosing
another chat system if the local usage asks for it.  As local teams
will write in their native languages, we don't want each team in a
single channel.  It's also natural for the local teams to reuse
their local channels like "#python-fr" for French translators.


Repository for PO Files
'''''''''''''''''''''''

Considering that each translation team may want to use different
translation tools, and that those tools should easily be synchronized
with git, all translations should expose their ``.po`` files via a git
repository.

Considering that each translation will be exposed via git
repositories, and that Python has migrated to GitHub, translations
will be hosted on GitHub.

For consistency and discoverability, all translations should be in the
same GitHub organization and named according to a common pattern.

Given that we want translations to be official, and that Python
already has a GitHub organization, translations should be hosted as
projects of the `Python GitHub organization`_.

For consistency, translation repositories should be called
``python-docs-LANGUAGE_TAG`` [22]_, using the language tag used in
paths: without region subtag if redundant, and lowercased.

The docsbuild-scripts may enforce this rule by refusing to fetch
outside of the Python organization or a wrongly named repository.

The CLA bot may be used on the translation repositories, but with a
limited effect as local coordinators may synchronize themselves with
translations from an external tool, like transifex, and lose track
of who translated what in the process.

Versions can be hosted on different repositories, different directories
or different branches.  Storing them on different repositories will
probably pollute the Python GitHub organization.  As it
is typical and natural to use branches to separate versions, branches
should be used to do so.

.. _Python GitHub organization: https://github.com/python/


Translation tools
'''''''''''''''''

Most of the translation work is actually done on Transifex [15]_.

Other tools may be used later like https://pontoon.mozilla.org/
and http://zanata.org/.


Documentation Contribution Agreement
''''''''''''''''''''''''''''''''''''

Documentation does require a license from the translator, as it
involves creativity in the expression of the ideas.

There's multiple solutions, quoting Van Lindberg from the PSF asked
about the subject:

  1. Docs should either have the copyright assigned or be under CCO. A
     permissive software license (like Apache or MIT) would also get the
     job done, although it is not quite fit for task.

  2. The translators should either sign an agreement or submit a
     declaration of the license with the translation.

  3. We should have in the project page an invitation for people to
     contribute under a defined license, with acceptance defined by their
     act of contribution. Such as:

  "By posting this project on Transifex and inviting you to
  participate, we are proposing an agreement that you will provide
  your translation for the PSF's use under the CC0 license. In return,
  you may noted that you were the translator for the portion you
  translate. You signify acceptance of this agreement by submitting
  your work to the PSF for inclusion in the documentation."


It looks like having a "Documentation Contribution Agreement"
is the most simple thing we can do as we can use multiple ways (GitHub
bots, invitation page, …) in different context to ensure contributors
are agreeing with it.


Language Team
'''''''''''''

Each language team should have one coordinator responsible for:

- Managing the team.
- Choosing and managing the tools the team will use (chat, mailing list, …).
- Ensure contributors understand and agree with the documentation
  contribution agreement.
- Ensure quality (grammar, vocabulary, consistency, filtering spam, ads, …).
- Redirect issues posted on b.p.o to the correct GitHub issue tracker
  for the language.


Alternatives
------------

Simplified English
''''''''''''''''''

It would be possible to introduce a "simplified English" version like
Wikipedia did [10]_, as discussed on python-dev [11]_, targeting
English learners and children.

Pros: It yields a single translation, theoretically readable by
everyone and reviewable by current maintainers.

Cons: Subtle details may be lost, and translators from English to English
may be hard to find as stated by Wikipedia:

> The main English Wikipedia has 5 million articles, written by nearly
140K active users; the Swedish Wikipedia is almost as big, 3M articles
from only 3K active users; but the Simple English Wikipedia has just
123K articles and 871 active users.  That's fewer articles than
Esperanto!


Changes
=======

Get a Documentation Contribution Agreement
------------------------------------------

The Documentation Contribution Agreement have to be written by the
PSF, then listed at https://www.python.org/psf/contrib/ and have its
own page like https://www.python.org/psf/contrib/doc-contrib-form/.


Migrate GitHub Repositories
---------------------------

We (authors of this PEP) already own French and Japanese Git repositories,
so moving them to the Python documentation organization will not be a
problem.  We'll however be following the `New Translation Procedure`_.


Setup a GitHub bot for Documentation Contribution Agreement
-----------------------------------------------------------

To help ensuring contributors from GitHub have signed the
Documentation Contribution Agreement, We can setup the "The Knights
Who Say Ni" GitHub bot customized for this agreement on the migrated
repositories [28]_.


Patch docsbuild-scripts to Compile Translations
-----------------------------------------------

Docsbuild-script must be patched to:

- List the language tags to build along with the branches to build.
- List the language tags to display in the language switcher.
- Find translation repositories by formatting
  ``github.com:python/python-docs-{language_tag}.git`` (See
  `Repository for Po Files`_)
- Build translations for each branch and each language.

Patched docsbuild-scripts must only open ``.po`` files from
translation repositories.


List coordinators in the devguide
---------------------------------

Add a page or a section with an empty list of coordinators to the
devguide, each new coordinator will be added to this list.


Create sphinx-doc Language Switcher
-----------------------------------

Highly similar to the version switcher, a language switcher must be
implemented.  This language switcher must be configurable to hide or
show a given language.

The language switcher will only have to update or add the language
segment to the path like the current version switcher does.  Unlike
the version switcher, no preflight are required as destination page
always exists (translations does not add or remove pages).
Untranslated (but existing) pages still exists, they should however be
rendered as so, see `Enhance Rendering of Untranslated and Fuzzy
Translations`_.


Update sphinx-doc Version Switcher
----------------------------------

The ``patch_url`` function of the version switcher in
``version_switch.js`` have to be updated to understand and allow the
presence of the language segment in the path.


Enhance Rendering of Untranslated and Fuzzy Translations
--------------------------------------------------------

It's an opened sphinx issue [9]_, but we'll need it so we'll have to
work on it.  Translated, fuzzy, and untranslated paragraphs should be
differentiated.  (Fuzzy paragraphs have to warn the reader what he's
reading may be out of date.)


New Translation Procedure
=========================

Designate a Coordinator
-----------------------

The first step is to designate a coordinator, see `Language Team`_,
The coordinator must sign the CLA.

The coordinator should be added to the list of translation coordinators
on the devguide.


Create GitHub Repository
------------------------

Create a repository named "python-docs-{LANGUAGE_TAG}" (IETF language
tag, without redundant region subtag, with a dash, and lowercased.) on
the Python GitHub organization (See `Repository For Po Files`_.), and
grant the language coordinator push rights to this repository.


Setup the Documentation Contribution Agreement
----------------------------------------------

The README file should clearly show the following Documentation
Contribution Agreement::

   NOTE REGARDING THE LICENSE FOR TRANSLATIONS: Python's documentation is
   maintained using a global network of volunteers. By posting this
   project on Transifex, GitHub, and other public places, and inviting
   you to participate, we are proposing an agreement that you will
   provide your improvements to Python's documentation or the translation
   of Python's documentation for the PSF's use under the CC0 license
   (available at
   `https://creativecommons.org/publicdomain/zero/1.0/legalcode`_). In
   return, you may publicly claim credit for the portion of the
   translation you contributed and if your translation is accepted by the
   PSF, you may (but are not required to) submit a patch including an
   appropriate annotation in the Misc/ACKS or TRANSLATORS file. Although
   nothing in this Documentation Contribution Agreement obligates the PSF
   to incorporate your textual contribution, your participation in the
   Python community is welcomed and appreciated.

   You signify acceptance of this agreement by submitting your work to
   the PSF for inclusion in the documentation.


Add support for translations in docsbuild-scripts
-------------------------------------------------

As soon as the translation hits its first commits, update the
docsbuild-scripts configuration to build the translation (but not
displaying it in the language switcher).


Add Translation to the Language Switcher
----------------------------------------

As soon as the translation hits:

- 100% of bugs.html with proper links to the language repository
  issue tracker.
- 100% of tutorial.
- 100% of library/functions (builtins).

the translation can be added to the language switcher.


Previous Discussions
====================

`[Python-ideas] Cross link documentation translations (January, 2016)
<https://mail.python.org/pipermail/python-ideas/2016-January/038010.html>`__

`[Python-Dev] Translated Python documentation (February 2016)
<https://mail.python.org/pipermail/python-dev/2017-February/147416.html>`__

`[Python-ideas] https://docs.python.org/fr/ ? (March 2016)
<https://mail.python.org/pipermail/python-ideas/2016-March/038879.html>`__


References
==========

.. [1] [I18n-sig] Hello Python members, Do you have any idea about
   Python documents?
   (https://mail.python.org/pipermail/i18n-sig/2013-September/002130.html)

[2] [Doc-SIG] Localization of Python docs
\   (https://mail.python.org/pipermail/doc-sig/2013-September/003948.html)

.. [4] IETF language tag
   (https://en.wikipedia.org/wiki/IETF_language_tag)

.. [5] GNU Gettext manual, section 2.3.1: Locale Names
   (https://www.gnu.org/software/gettext/manual/html_node/Locale-Names.html)

.. [6] Semantic URL: Slug
   (https://en.wikipedia.org/wiki/Clean_URL#Slug)

.. [8] Docsbuild-scripts GitHub repository
   (https://github.com/python/docsbuild-scripts/)

.. [9] i18n: Highlight untranslated paragraphs
   (https://github.com/sphinx-doc/sphinx/issues/1246)

.. [10] Wikipedia: Simple English
   (https://simple.wikipedia.org/wiki/Main_Page)

.. [11] Python-dev discussion about simplified English
   (https://mail.python.org/pipermail/python-dev/2017-February/147446.html)

.. [12] Passing options to sphinx from Doc/Makefile
   (https://github.com/python/cpython/commit/57acb82d275ace9d9d854b156611e641f68e9e7c)

.. [13] French translation progression
   (https://mdk.fr/pycon2016/#/11)

.. [14] French translation contributors
   (https://github.com/AFPy/python_doc_fr/graphs/contributors?from=2016-01-01&to=2016-12-31&type=c)

.. [15] Python-doc on Transifex
   (https://www.transifex.com/python-doc/public/)

.. [16] French translation
   (https://www.afpy.org/doc/python/)

.. [17] French translation on Gitea
   (https://git.afpy.org/AFPy/python-docs-fr)

.. [18] French mailing list
   (http://lists.afpy.org/mailman/listinfo/traductions)

.. [19] Japanese translation
   (http://docs.python.jp/3/)

.. [20] Japanese translation on GitHub
   (https://github.com/python-doc-ja/python-doc-ja)

.. [21] Spanish translation
   (https://docs.python.org/es/3/tutorial/index.html)

.. [22] [Python-Dev] Translated Python documentation: doc vs docs
   (https://mail.python.org/pipermail/python-dev/2017-February/147472.html)

.. [23] Domains - SEO Best Practices | Moz
   (https://moz.com/learn/seo/domain)

.. [24] Accept-Language
   (https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Language)

.. [25] Документация Python 2.7!
   (http://python-lab.ru/documentation/index.html)

.. [26] Python-oktató
   (http://web.archive.org/web/20170526080729/http://harp.pythonanywhere.com/python_doc/tutorial/index.html)

.. [27] The Python-hu Archives
   (https://mail.python.org/pipermail/python-hu/)

.. [28] [Python-Dev] PEP 545: Python Documentation Translations
   (https://mail.python.org/pipermail/python-dev/2017-April/147752.html)


Copyright
=========

This document has been placed in the public domain.