From 6d863fef8a992ef28b081e9fa6043e4a9799e965 Mon Sep 17 00:00:00 2001
From: Gary Wilson Jr <gary.wilson@gmail.com>
Date: Fri, 15 Aug 2008 21:08:11 +0000
Subject: [PATCH] Fixed #5270 -- Allow template tags and filters to accept an
 emtpy string, patch from jdunck.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@8393 bcc190cf-cafb-0310-a4f2-bffc1f526a37
---
 django/template/__init__.py              | 11 ++++++++---
 tests/regressiontests/templates/tests.py |  8 ++++++--
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/django/template/__init__.py b/django/template/__init__.py
index 5c4ab3052a..ffdb4e4809 100644
--- a/django/template/__init__.py
+++ b/django/template/__init__.py
@@ -485,9 +485,14 @@ class FilterExpression(object):
                                            (token[:upto], token[upto:start], token[start:]))
             if var == None:
                 var, constant, i18n_constant = match.group("var", "constant", "i18n_constant")
-                if i18n_constant:
-                    var = '"%s"' %  _(i18n_constant.replace(r'\"', '"'))
-                elif constant:
+                if i18n_constant is not None:
+                    # Don't pass the empty string to gettext, because the empty
+                    # string translates to meta information.
+                    if i18n_constant == "":
+                        var = '""'
+                    else:
+                        var = '"%s"' %  _(i18n_constant.replace(r'\"', '"'))
+                elif constant is not None:
                     var = '"%s"' % constant.replace(r'\"', '"')
                 upto = match.end()
                 if var == None:
diff --git a/tests/regressiontests/templates/tests.py b/tests/regressiontests/templates/tests.py
index 13b8c6b488..96e1d662c6 100644
--- a/tests/regressiontests/templates/tests.py
+++ b/tests/regressiontests/templates/tests.py
@@ -365,6 +365,9 @@ class Templates(unittest.TestCase):
 
             # Numbers as filter arguments should work
             'filter-syntax19': ('{{ var|truncatewords:1 }}', {"var": "hello world"}, "hello ..."),
+            
+            #filters should accept empty string constants
+            'filter-syntax20': ('{{ ""|default_if_none:"was none" }}', {}, ""),
 
             ### COMMENT SYNTAX ########################################################
             'comment-syntax01': ("{# this is hidden #}hello", {}, "hello"),
@@ -770,11 +773,12 @@ class Templates(unittest.TestCase):
             'i18n14': ('{% cycle "foo" _("Password") _(\'Password\') as c %} {% cycle c %} {% cycle c %}', {'LANGUAGE_CODE': 'de'}, 'foo Passwort Passwort'),
             'i18n15': ('{{ absent|default:_("Password") }}', {'LANGUAGE_CODE': 'de', 'absent': ""}, 'Passwort'),
             'i18n16': ('{{ _("<") }}', {'LANGUAGE_CODE': 'de'}, '<'),
+            'i18n17': ('{{ _("") }}', {'LANGUAGE_CODE': 'de'}, ''),
 
             # Escaping inside blocktrans works as if it was directly in the
             # template.
-            'i18n17': ('{% load i18n %}{% blocktrans with anton|escape as berta %}{{ berta }}{% endblocktrans %}', {'anton': 'α & β'}, u'α &amp; β'),
-            'i18n18': ('{% load i18n %}{% blocktrans with anton|force_escape as berta %}{{ berta }}{% endblocktrans %}', {'anton': 'α & β'}, u'α &amp; β'),
+            'i18n18': ('{% load i18n %}{% blocktrans with anton|escape as berta %}{{ berta }}{% endblocktrans %}', {'anton': 'α & β'}, u'α &amp; β'),
+            'i18n19': ('{% load i18n %}{% blocktrans with anton|force_escape as berta %}{{ berta }}{% endblocktrans %}', {'anton': 'α & β'}, u'α &amp; β'),
 
             ### HANDLING OF TEMPLATE_STRING_IF_INVALID ###################################