id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
7034	get_nodes_by_type() fails if nodelist = None	kilian	nobody	"Using [http://toys.jacobian.org/hg/googlecharts/ Jacob's Google Charts templatetags], I've encountered a strange bug in the template systems. The `{% axis ""bottom"" hide %}` directive works fine in a stand-alone template, but fails if the template extends an other template. 

For instance, the following template (straight from the examples):
{{{
{% extends ""base.html"" %}
{% load charts %}
{% chart %}
  {% chart-size ""300x200"" %}
  {% chart-type ""line"" %}
  {% chart-data ""1,5,2,10"" %}
  {% axis ""left"" %}
    {% axis-range ""0"" ""10"" %}
  {% endaxis %}
  {% axis ""left"" hide %}
{% endchart %}
}}}
raises the following exception:
{{{
File ""/home/kilian/django/django/template/__init__.py"" in get_nodes_by_type
  762.             nodes.extend(node.get_nodes_by_type(nodetype))
File ""/home/kilian/django/django/template/__init__.py"" in get_nodes_by_type
  741.             nodes.extend(self.nodelist.get_nodes_by_type(nodetype))

Exception Type: AttributeError at /test/
Exception Value: 'NoneType' object has no attribute 'get_nodes_by_type'
}}}

If the `{% extends ""base.html"" %}` is removed from the template, then it works fine, and no exception is raised. It looks like, for some reason, the parsing of the `{% axis ""left"" hide %}` tag generates a Node whose `nodelist` attribute is not a !NodeList object. neither a list, but rather None. 

The attached patch proposes a solution to take care of this case.
"		closed	Template system	dev		invalid	inheritance nodelist		Unreviewed	1	0	0	0	0	0