Ticket #12068: 12068.diff

django/template/defaulttags.py

@@ -1118 +1118 @@
     if len(bits) > 2:
         bits = iter(bits[2:])
         for bit in bits:
+
             if bit == 'as':
-                asvar = bits.next()
-                break
-            else:
-                for arg in bit.split(","):
-                    if '=' in arg:
-                        k, v = arg.split('=', 1)
-                        k = k.strip()
-                        kwargs[k] = parser.compile_filter(v)
-                    elif arg:
-                        args.append(parser.compile_filter(arg))
+                try:
+                    asvar = bits.next()
+
+                    # "as" cannot be the argument of the 'as' keyword, because it is
+                    # ambiguous:
+                    #
+                    #    {% url view as as %}
+                    # 
+                    # Meaning 1. This is an 'as' variable and an incomplete 'as' clause
+                    # Meaning 2. There is a complete 'as' clause and no variables
+
+                    if asvar == 'as':
+                        raise TemplateSyntaxError("'as' may not be used as the argument"
+                                                  " to an 'as' keyword")
+
+                    # We break out of this loop once we've processed an 'as' clause
+                    break
+
+                except StopIteration:
+                    # An incomplete 'as' clause is an error
+                    raise TemplateSyntaxError("'as' must be followed by an argument in"
+                                              " the 'url' template tag")
+
+
+            for arg in bit.split(","):
+                if '=' in arg:
+                    k, v = arg.split('=', 1)
+                    k = k.strip()
+                    kwargs[k] = parser.compile_filter(v)
+                elif arg:
+                    args.append(parser.compile_filter(arg))
+
     return URLNode(viewname, args, kwargs, asvar)
 url = register.tag(url)
 

tests/regressiontests/templates/tests.py

@@ -181 +181 @@
         settings.SETTINGS_MODULE = old_settings_module
         settings.TEMPLATE_DEBUG = old_template_debug
 
+    def test_url_incomplete_as_clause(self):
+        # Regression test for #12068
+        from django.template import Template, TemplateSyntaxError
+
+        # The 'as' keyword is reserved in the url tag, and must be followed by a name
+        # (which is not 'as')
+
+        self.assertRaises(TemplateSyntaxError, Template, '{% url view as %}')
+        self.assertRaises(TemplateSyntaxError, Template, '{% url view as as %}')
+
     def test_templates(self):
         template_tests = self.get_template_tests()
         filter_tests = filters.get_filter_tests()

docs/ref/templates/builtins.txt

@@ -947 +947 @@
       <a href="{{ the_url }}">Link to optional stuff</a>
     {% endif %}
 
+Note that "as" is a reserved keyword, which can't be used as a variable name or as
+the value of ``var``, as below::
+
+    {% url path.to.view as %}
+    {% url path.to.view as as %}
+
+
 .. versionadded:: 1.1
 
 If you'd like to retrieve a namespaced URL, specify the fully qualified name::