Do not perform string formatting if no variables were passed.

Fixes complaints raised by the CKAN project and reflects the behaviour
of Python, pylons, and django's gettext().

Author: TkTech

flask_babel/__init__.py

@@ -532,8 +532,9 @@ def gettext(string, **variables):
     """
     t = get_translations()
     if t is None:
-        return string % variables
-    return t.ugettext(string) % variables
+        return string if not variables else string % variables
+    s = t.ugettext(string)
+    return s if not variables else s % variables
 _ = gettext
 
 
@@ -552,8 +553,11 @@ def ngettext(singular, plural, num, **variables):
     variables.setdefault('num', num)
     t = get_translations()
     if t is None:
-        return (singular if num == 1 else plural) % variables
-    return t.ungettext(singular, plural, num) % variables
+        s = singular if num == 1 else plural
+        return s if not variables else s % variables
+
+    s = t.ungettext(singular, plural, num)
+    return s if not variables else s % variables
 
 
 def pgettext(context, string, **variables):
@@ -563,8 +567,9 @@ def pgettext(context, string, **variables):
     """
     t = get_translations()
     if t is None:
-        return string % variables
-    return t.upgettext(context, string) % variables
+        return string if not variables else string % variables
+    s = t.upgettext(context, string)
+    return s if not variables else s % variables
 
 
 def npgettext(context, singular, plural, num, **variables):
@@ -575,8 +580,10 @@ def npgettext(context, singular, plural, num, **variables):
     variables.setdefault('num', num)
     t = get_translations()
     if t is None:
-        return (singular if num == 1 else plural) % variables
-    return t.unpgettext(context, singular, plural, num) % variables
+        s = singular if num == 1 else plural
+        return s if not variables else s % variables
+    s = t.unpgettext(context, singular, plural, num)
+    return s if not variables else s % variables
 
 
 def lazy_gettext(string, **variables):

tests/tests.py

@@ -229,6 +229,18 @@ def test_list_translations(self):
         assert len(translations) == 1
         assert str(translations[0]) == 'de'
 
+    def test_no_formatting(self):
+        """
+        Ensure we don't format strings unless a variable is passed.
+        """
+        app = flask.Flask(__name__)
+        babel.Babel(app)
+
+        with app.test_request_context():
+            assert gettext(u'Test %s') == u'Test %s'
+            assert gettext(u'Test %(name)s', name=u'test') == u'Test test'
+            assert gettext(u'Test %s') % 'test' == u'Test test'
+
 
 if __name__ == '__main__':
     unittest.main()