Fixed #24063 -- Allowed locale variants supported by gettext.

The locale code can contain a variant after @, so allowed that.

django/utils/translation/trans_real.py

@@ -43,9 +43,12 @@ accept_language_re = re.compile(r'''
         (?:\s*,\s*|$)                                 # Multiple accepts per header.
         ''', re.VERBOSE)
 
-language_code_re = re.compile(r'^[a-z]{1,8}(?:-[a-z0-9]{1,8})*$', re.IGNORECASE)
+language_code_re = re.compile(
+    r'^[a-z]{1,8}(?:-[a-z0-9]{1,8})*(?:@[a-z0-9]{1,20})?$',
+    re.IGNORECASE
+)
 
-language_code_prefix_re = re.compile(r'^/([\w-]+)(/|$)')
+language_code_prefix_re = re.compile(r'^/([\w@-]+)(/|$)')
 
 
 @receiver(setting_changed)

docs/releases/1.9.txt

@@ -162,6 +162,10 @@ Internationalization
 * The :func:`django.utils.timezone.make_aware` function gained an ``is_dst``
   argument to help resolve ambiguous times during DST transitions.
 
+* You can now use locale variants supported by gettext. These are usually used
+  for languages which can be written in different scripts, for example Latin
+  and Cyrillic (e.g. ``be@latin``).
+
 Management Commands
 ^^^^^^^^^^^^^^^^^^^
 

tests/i18n/tests.py

@@ -1420,9 +1420,18 @@ class CountrySpecificLanguageTests(TestCase):
         self.assertTrue(check_for_language('en'))
         self.assertTrue(check_for_language('en-us'))
         self.assertTrue(check_for_language('en-US'))
+        self.assertTrue(check_for_language('be'))
+        self.assertTrue(check_for_language('be@latin'))
+        self.assertTrue(check_for_language('sr-RS@latin'))
+        self.assertTrue(check_for_language('sr-RS@12345'))
         self.assertFalse(check_for_language('en-ü'))
         self.assertFalse(check_for_language('en\x00'))
         self.assertFalse(check_for_language(None))
+        self.assertFalse(check_for_language('be@ '))
+        # Specifying encoding is not supported (Django enforces UTF-8)
+        self.assertFalse(check_for_language('tr-TR.UTF-8'))
+        self.assertFalse(check_for_language('tr-TR.UTF8'))
+        self.assertFalse(check_for_language('de-DE.utf-8'))
 
     def test_get_language_from_request(self):
         # issue 19919