Refs #13167 -- Corrected a regression in the way non-existent variables are…

Refs #13167 -- Corrected a regression in the way non-existent variables are handled by {% if %} tags. Thanks to ohmi2 for pointing out the regression in 1.2, and Karen for the patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12954 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/template/defaulttags.py

@@ -243,7 +243,12 @@ class IfNode(Node):
             yield node
 
     def render(self, context):
-        if self.var.eval(context):
+        try:
+            var = self.var.eval(context)
+        except VariableDoesNotExist:
+            var = None
+
+        if var:
             return self.nodelist_true.render(context)
         else:
             return self.nodelist_false.render(context)

tests/regressiontests/templates/tests.py

@@ -782,6 +782,12 @@ class Templates(unittest.TestCase):
             'if-tag-error11': ("{% if 1 == %}yes{% endif %}", {}, template.TemplateSyntaxError),
             'if-tag-error12': ("{% if a not b %}yes{% endif %}", {}, template.TemplateSyntaxError),
 
+            # Non-existent args
+            'if-tag-badarg01':("{% if x|default_if_none:y %}yes{% endif %}", {}, ''),
+            'if-tag-badarg02':("{% if x|default_if_none:y %}yes{% endif %}", {'y': 0}, ''),
+            'if-tag-badarg03':("{% if x|default_if_none:y %}yes{% endif %}", {'y': 1}, 'yes'),
+            'if-tag-badarg04':("{% if x|default_if_none:y %}yes{% else %}no{% endif %}", {}, 'no'),
+
             # Additional, more precise parsing tests are in SmartIfTests
 
             ### IFCHANGED TAG #########################################################