Allow to import overridden translations from different po-file

issue4971
review18581002

CHANGELOG

@@ -1,3 +1,4 @@
+* Load po files also in 'override' subdirectory
 * Add support for float and integer on Property fields
 * Remove foreign-key on create_uid and write_uid
 * Prevent deletion of any user

doc/topics/index.rst

@@ -25,3 +25,4 @@ Introduction to all the key parts of trytond:
     wizard
     reports/index
     modules/index
+    translation

doc/topics/translation.rst

@@ -0,0 +1,64 @@
+.. _topics-translation:
+
+===========
+Translation
+===========
+
+The translation of the user interface is provided module-wise.
+Translations are stored in the ``locale/`` directory of a module, each language
+in a `PO-file <https://en.wikipedia.org/wiki/Gettext#Translating>`_. The
+official language files are named after the
+`POSIX locale <https://en.wikipedia.org/wiki/Locale#POSIX_platforms>`_
+standard, e.g. de_DE.po, es_AR.po, es_EC.po...
+
+The names of custom language files must match the code of the language in the
+Model ir.lang.
+
+If a language is set ``translatable``, the translations will be loaded into
+the database on each trytond module update.
+
+
+Translation Wizards
+===================
+
+Set Report Translations Wizard
+------------------------------
+
+The wizard adds new translations to the base language ``en_US``.
+
+Clean Translations Wizard
+-------------------------
+
+The wizard deletes obsolete translations from the database.
+
+Synchronize Translations Wizard
+-------------------------------
+
+The wizard updates the translations of the selected language based on the
+translations of the base language ``en_US``.
+
+Export Translations Wizard
+--------------------------
+
+The wizard requires to select a language and a module and will export the
+translations for this selection into a PO-file.
+
+
+Override translations
+=====================
+
+Translations of a module can be overridden by another module. This can be done
+by putting a PO file into the ``locale/override`` directory of the module that
+shall contain the translations to override.
+
+To override the translation of another module the ``msgctxt`` string must have
+the following content:
+
+type:name:module.xml_id
+
+    * ``type``: Value of the field type of ir.translation.
+    * ``name``: Value of the field name of ir.translation.
+    * ``module``: Value of the field module ir.translation.
+    * ``xml_id``: The XML id that is stored in ir.model.data as fs_id
+
+The xml_id part is optional and can be omitted if it is None.

trytond/modules/__init__.py

@@ -249,8 +249,10 @@ def load_module_graph(graph, pool, update=None, lang=None):
 
             modules_todo.append((module, list(tryton_parser.to_delete)))
 
-            for filename in iglob('%s/%s/*.po'
-                    % (package.info['directory'], 'locale')):
+            localedir = '%s/%s' % (package.info['directory'], 'locale')
+            for filename in itertools.chain(
+                    iglob('%s/*.po' % localedir),
+                    iglob('%s/override/*.po' % localedir)):
                 filename = filename.replace('/', os.sep)
                 lang2 = os.path.splitext(os.path.basename(filename))[0]
                 if lang2 not in lang: