From b9e088ae14141ccb6a5aaf7952868a6e15e1a6c7 Mon Sep 17 00:00:00 2001
From: Malcolm Tredinnick <malcolm.tredinnick@gmail.com>
Date: Mon, 4 Feb 2008 04:52:37 +0000
Subject: [PATCH] Fixed #5124 -- Added a reasonable error when "extends" is not
 the first template tag. Patch from k0001.

Refs #6274.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@7084 bcc190cf-cafb-0310-a4f2-bffc1f526a37
---
 django/template/__init__.py    | 7 +++++++
 django/template/loader_tags.py | 7 +++++++
 2 files changed, 14 insertions(+)

diff --git a/django/template/__init__.py b/django/template/__init__.py
index 750c48988d..c53d400f3c 100644
--- a/django/template/__init__.py
+++ b/django/template/__init__.py
@@ -289,6 +289,9 @@ class Parser(object):
         return NodeList()
 
     def extend_nodelist(self, nodelist, node, token):
+        if (node.must_be_first and nodelist and
+                (not isinstance(nodelist[0], TextNode) or len(nodelist) > 2)):
+            raise TemplateSyntaxError("%r must be the first tag in the template." % node)
         nodelist.append(node)
 
     def enter_command(self, command, token):
@@ -708,6 +711,10 @@ class Variable(object):
         return current
 
 class Node(object):
+    # Set this to True for nodes that must be first in the template (although
+    # they can be preceded by text nodes.
+    must_be_first = False
+
     def render(self, context):
         "Return the node rendered as a string"
         pass
diff --git a/django/template/loader_tags.py b/django/template/loader_tags.py
index ef4d8ab23a..7597c04b73 100644
--- a/django/template/loader_tags.py
+++ b/django/template/loader_tags.py
@@ -37,11 +37,18 @@ class BlockNode(Node):
             self.parent = BlockNode(self.name, nodelist)
 
 class ExtendsNode(Node):
+    must_be_first = True
+
     def __init__(self, nodelist, parent_name, parent_name_expr, template_dirs=None):
         self.nodelist = nodelist
         self.parent_name, self.parent_name_expr = parent_name, parent_name_expr
         self.template_dirs = template_dirs
 
+    def __repr__(self):
+        if self.parent_name_expr:
+            return "<ExtendsNode: extends %s>" % self.parent_name_expr.token
+        return '<ExtendsNode: extends "%s">' % self.parent_name
+
     def get_parent(self, context):
         if self.parent_name_expr:
             self.parent_name = self.parent_name_expr.resolve(context)