Fixed #24569 -- Made some translation functions accept None value

get_language() can return None when translations are deactivated.
Thanks Nicola Peduzzi for the reporti and Tim Graham for the review.

django/utils/translation/trans_real.py

@@ -248,6 +248,10 @@ def get_language_bidi():
     * False = left-to-right layout
     * True = right-to-left layout
     """
+    lang = get_language()
+    if lang is None:
+        return False
+    else:
         base_lang = get_language().split('-')[0]
         return base_lang in settings.LANGUAGES_BIDI
 
@@ -394,7 +398,7 @@ def check_for_language(lang_code):
     <https://www.djangoproject.com/weblog/2007/oct/26/security-fix/>.
     """
     # First, a quick check to make sure lang_code is well-formed (#21458)
-    if not language_code_re.search(lang_code):
+    if lang_code is None or not language_code_re.search(lang_code):
         return False
     for path in all_locale_paths():
         if gettext_module.find('django', path, [to_locale(lang_code)]) is not None:

docs/releases/1.8.1.txt

@@ -14,3 +14,6 @@ Bugfixes
 
 * Restored proper parsing of the :djadmin:`testserver` command's positional
   arguments (fixture names) (:ticket:`24571`).
+
+* Prevented ``TypeError`` in translation functions ``check_for_language()`` and
+  ``get_language_bidi()`` when translations are deactivated (:ticket:`24569`).

tests/i18n/tests.py

@@ -27,10 +27,10 @@ from django.utils.safestring import SafeBytes, SafeString, SafeText, mark_safe
 from django.utils.six import PY3
 from django.utils.translation import (
     LANGUAGE_SESSION_KEY, activate, check_for_language, deactivate,
-    get_language, get_language_from_request, get_language_info, gettext,
-    gettext_lazy, ngettext_lazy, npgettext, npgettext_lazy, pgettext,
-    pgettext_lazy, string_concat, to_locale, trans_real, ugettext,
-    ugettext_lazy, ungettext, ungettext_lazy,
+    get_language, get_language_bidi, get_language_from_request,
+    get_language_info, gettext, gettext_lazy, ngettext_lazy, npgettext,
+    npgettext_lazy, pgettext, pgettext_lazy, string_concat, to_locale,
+    trans_real, ugettext, ugettext_lazy, ungettext, ungettext_lazy,
 )
 
 from .forms import CompanyForm, I18nForm, SelectDateForm
@@ -398,6 +398,11 @@ class TranslationTests(TestCase):
         self.assertEqual(trans_real.to_language('en_US'), 'en-us')
         self.assertEqual(trans_real.to_language('sr_Lat'), 'sr-lat')
 
+    def test_language_bidi(self):
+        self.assertEqual(get_language_bidi(), False)
+        with translation.override(None):
+            self.assertEqual(get_language_bidi(), False)
+
     @override_settings(LOCALE_PATHS=[os.path.join(here, 'other', 'locale')])
     def test_bad_placeholder_1(self):
         """
@@ -1417,6 +1422,7 @@ class CountrySpecificLanguageTests(TestCase):
         self.assertTrue(check_for_language('en-US'))
         self.assertFalse(check_for_language('en-ü'))
         self.assertFalse(check_for_language('en\x00'))
+        self.assertFalse(check_for_language(None))
 
     def test_get_language_from_request(self):
         # issue 19919