Ticket #13167: r12820_with_tests.diff

django/template/__init__.py

@@ -570 +570 @@
                 if not lookup:
                     arg_vals.append(mark_safe(arg))
                 else:
-                    arg_vals.append(arg.resolve(context))
+                    try:
+                        arg_vals.append(arg.resolve(context))
+                    except VariableDoesNotExist:
+                        arg_vals.append(settings.TEMPLATE_STRING_IF_INVALID)
             if getattr(func, 'needs_autoescape', False):
                 new_obj = func(obj, autoescape=context.autoescape, *arg_vals)
             else:

tests/regressiontests/templates/tests.py

@@ -551 +551 @@
 
             #filters should accept empty string constants
             'filter-syntax20': ('{{ ""|default_if_none:"was none" }}', {}, ""),
+            
+            # regression test for #13167
+            'filter-syntax21': ("{{ foo|default:notreal }}", {'foo': 'test'}, ('test', 'test')), 
+            'filter-syntax22': ("{{ foo|default:notreal }}", {'foo': ''}, ('', 'INVALID')),
 
             ### COMMENT SYNTAX ########################################################
             'comment-syntax01': ("{# this is hidden #}hello", {}, "hello"),