[1.0.X] Fixed #10014 -- Don't crash when using debug template tag inside a block node tag.

Returning non-ASCII characters from TextNode.__repr__ was causing
problems in the BlockNode.__repr__ method (and probably in other places
we don't know about yet). We now forcibly convert to ascii and replace any
unconvertible characters, rather than returning some moderately
corrupted data in the non-ASCII case.

Backport of r9757 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@9758 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/template/__init__.py

@@ -55,7 +55,7 @@ from django.template.context import Context, RequestContext, ContextPopException
 from django.utils.itercompat import is_iterable
 from django.utils.functional import curry, Promise
 from django.utils.text import smart_split
-from django.utils.encoding import smart_unicode, force_unicode
+from django.utils.encoding import smart_unicode, force_unicode, smart_str
 from django.utils.translation import ugettext as _
 from django.utils.safestring import SafeData, EscapeData, mark_safe, mark_for_escaping
 from django.utils.html import escape
@@ -785,7 +785,8 @@ class TextNode(Node):
         self.s = s
 
     def __repr__(self):
-        return "<Text Node: '%s'>" % self.s[:25]
+        return "<Text Node: '%s'>" % smart_str(self.s[:25], 'ascii',
+                errors='replace')
 
     def render(self, context):
         return self.s