Add support for language fallback.

3 files changed, 25 insertions, 1 deletions

diff --git a/CHANGES.txt b/CHANGES.txt
index 9dd1af2c5..0254ac2b0 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -42,6 +42,12 @@ Documentation
 Features
 --------
 
+- Add support for language fallbacks: when trying to translate for a
+  specific territory (such as ``en_GB``) fall back to translations
+  for the language (ie ``en``). This brings the translation behaviour in line
+  with GNU gettext and fixes partially translated texts when using C
+  extensions.
+
 - New authentication policy:
   ``pyramid.authentication.SessionAuthenticationPolicy``, which uses a session
   to store credentials.
diff --git a/pyramid/i18n.py b/pyramid/i18n.py
index 4b8281673..7bc096bb1 100644
--- a/pyramid/i18n.py
+++ b/pyramid/i18n.py
@@ -151,11 +151,16 @@ def make_localizer(current_locale_name, translation_directories):
     translations found in the list of translation directories."""
     translations = Translations()
     translations._catalog = {}
+
+    locales_to_try = [current_locale_name]
+    if '_' in current_locale_name:
+        locales_to_try.append(current_locale_name.split('_')[0])
+
     for tdir in translation_directories:
         locale_dirs = [ (lname, os.path.join(tdir, lname)) for lname in
                         os.listdir(tdir) ]
         for locale_name, locale_dir in locale_dirs:
-            if locale_name != current_locale_name:
+            if locale_name not in locales_to_try:
                 continue
             messages_dir = os.path.join(locale_dir, 'LC_MESSAGES')
             if not os.path.isdir(os.path.realpath(messages_dir)):
diff --git a/pyramid/tests/test_i18n.py b/pyramid/tests/test_i18n.py
index 588f0a7cc..97117a8cd 100644
--- a/pyramid/tests/test_i18n.py
+++ b/pyramid/tests/test_i18n.py
@@ -200,6 +200,19 @@ class Test_make_localizer(unittest.TestCase):
         self.assertEqual(result.translate('Approve', 'deformsite'),
                          'Approve')
 
+    def test_territory_fallback(self):
+        import os
+        from pyramid.i18n import Localizer
+        here = os.path.dirname(__file__)
+        localedir = os.path.join(here, 'localeapp', 'locale')
+        localedirs = [localedir]
+        locale_name = 'de_DE'
+        result = self._callFUT(locale_name, localedirs)
+        self.assertEqual(result.__class__, Localizer)
+        self.assertEqual(result.translate('Approve', 'deformsite'),
+                         'Genehmigen')
+
+
 class Test_get_localizer(unittest.TestCase):
     def setUp(self):
         cleanUp()