Ticket #12212: 12212.patch

django/template/__init__.py

@@ -929 +929 @@
                 self.vars_to_resolve = map(Variable, vars_to_resolve)
 
             def render(self, context):
-                resolved_vars = [var.resolve(context) for var in self.vars_to_resolve]
+                resolved_vars = []
+                for var in self.vars_to_resolve:
+                    try:
+                        resolved_vars.append(var.resolve(context))
+                    except VariableDoesNotExist:
+                        resolved_vars.append(None)
+               
                 return func(*resolved_vars)
 
         compile_func = curry(generic_tag_compiler, params, defaults, getattr(func, "_decorated_function", func).__name__, SimpleNode)
@@ -951 +957 @@
                     self.vars_to_resolve = map(Variable, vars_to_resolve)
 
                 def render(self, context):
-                    resolved_vars = [var.resolve(context) for var in self.vars_to_resolve]
+                    resolved_vars = []
+                    for var in self.vars_to_resolve:
+                        try:
+                            resolved_vars.append(var.resolve(context))
+                        except VariableDoesNotExist:
+                            resolved_vars.append(None)
+                    
                     if takes_context:
                         args = [context] + resolved_vars
                     else:

docs/howto/custom-template-tags.txt

@@ -669 +669 @@
       so we just receive a plain string.
     * If the argument was a template variable, our function is passed the
       current value of the variable, not the variable itself.
+    * If a variable with the argument's name does not exist in the context the
+      argument will be set to ``None``.
 
 When your template tag does not need access to the current context, writing a
 function to work with the input values and using the ``simple_tag`` helper is
@@ -788 +790 @@
 the tag is passed the context object, as in this example. That's the only
 difference between this case and the previous ``inclusion_tag`` example.
 
+.. note::
+    Named arguments in the function wrapped by ``inclusion_tag`` will be set
+    to ``None`` for variables that don't exist in the context. If
+    ``takes_context=True`` they will not exist in the ``context`` dictionary
+    either.
+
+
 Setting a variable in the context
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

tests/regressiontests/templates/taghelpers.py

@@ +1 @@
+import unittest
+from django.template import Template, Context
+
+class InclusionTagTests(unittest.TestCase):
+    def test_variable_not_found(self):
+        t = Template("{% load custom %}Testing - {% it_sample dog %}")
+        self.assertEqual(t.render(Context({})), u'Testing - None')
+
+    def test_variable_not_found_with_takes_context(self):
+        t = Template("{% load custom %}Testing - {% it_takes_context %}")
+        self.assertRaises(KeyError, t.render, Context({}))
+
+    def test_variable_not_found_with_takes_context_arg(self):
+        t = Template("{% load custom %}Testing - {% it_takes_context_arg dog %}")
+        self.assertEqual(t.render(Context({})), u'Testing - None')
+        
+class SimpleTagTests(unittest.TestCase):
+    def test_variable_not_found(self):
+        t = Template("{% load custom %}Testing - {% st_sample dog %}")
+        self.assertEqual(t.render(Context({})), u'Testing - None')

tests/regressiontests/templates/templatetags/custom.py

@@ -9 +9 @@
 
 register.filter(trim)
 
+def it_sample(foo):
+    return {'bar': foo}
+
+register.inclusion_tag('taghelpers_test.txt')(it_sample)
+
+def it_takes_context(context):
+    return {'bar': context['foo']}
+
+register.inclusion_tag('taghelpers_test.txt', takes_context=True)(it_takes_context)
+
+def it_takes_context_arg(context, foo):
+    return {'bar': foo}
+
+register.inclusion_tag('taghelpers_test.txt', takes_context=True)(it_takes_context_arg)
+
+def st_sample(foo):
+    return foo
+
+register.simple_tag(st_sample)
+ No newline at end of file

tests/regressiontests/templates/tests.py

@@ -25 +25 @@
 from parser import token_parsing, filter_parsing, variable_parsing
 from unicode import unicode_tests
 from nodelist import NodelistTest
-from smartif import *
+from smartif import SmartIfTests
+from taghelpers import InclusionTagTests, SimpleTagTests
 
 try:
     from loaders import *

tests/templates/taghelpers_test.txt

@@ +1 @@
+{{ bar }}
+ No newline at end of file