From 11f307a5a8fa66605652e0496c7385e584bfcad7 Mon Sep 17 00:00:00 2001
From: Yuri Kriachko <yuriykryachko@gmail.com>
Date: Sun, 7 Sep 2014 13:56:34 +0200
Subject: [PATCH] Fixed #23196 -- Short-circuited empty string translation

Translating an empty string used to return the gettext catalog
metadata instead of the empty string.
Thanks Ned Batchelder for the suggestion, Tim Graham for the review
and Anton Berezin and Claude Paroz for contributions to the patch.
---
 django/utils/translation/trans_real.py | 17 +++++++++++------
 tests/i18n/tests.py                    | 10 ++++++++++
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/django/utils/translation/trans_real.py b/django/utils/translation/trans_real.py
index 3d94f22348..dd40ac5de2 100644
--- a/django/utils/translation/trans_real.py
+++ b/django/utils/translation/trans_real.py
@@ -292,15 +292,20 @@ def do_translate(message, translation_function):
 
     # str() is allowing a bytestring message to remain bytestring on Python 2
     eol_message = message.replace(str('\r\n'), str('\n')).replace(str('\r'), str('\n'))
-    t = getattr(_active, "value", None)
-    if t is not None:
-        result = getattr(t, translation_function)(eol_message)
+
+    if len(eol_message) == 0:
+        # Returns an empty value of the corresponding type if an empty message
+        # is given, instead of metadata, which is the default gettext behavior.
+        result = type(message)("")
     else:
-        if _default is None:
-            _default = translation(settings.LANGUAGE_CODE)
-        result = getattr(_default, translation_function)(eol_message)
+        _default = _default or translation(settings.LANGUAGE_CODE)
+        translation_object = getattr(_active, "value", _default)
+
+        result = getattr(translation_object, translation_function)(eol_message)
+
     if isinstance(message, SafeData):
         return mark_safe(result)
+
     return result
 
 
diff --git a/tests/i18n/tests.py b/tests/i18n/tests.py
index 321f3b17e2..9cf979ab16 100644
--- a/tests/i18n/tests.py
+++ b/tests/i18n/tests.py
@@ -345,6 +345,16 @@ class TranslationTests(TestCase):
         """
         self.assertEqual('django', six.text_type(string_concat("dja", "ngo")))
 
+    def test_empty_value(self):
+        """
+        Empty value must stay empty after being translated (#23196).
+        """
+        with translation.override('de'):
+            self.assertEqual("", ugettext(""))
+            self.assertEqual(b"", gettext(b""))
+            s = mark_safe("")
+            self.assertEqual(s, ugettext(s))
+
     def test_safe_status(self):
         """
         Translating a string requiring no auto-escaping shouldn't change the "safe" status.