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
36271	{% extends %} tag causes AttributeError if origin is None and path is relative	Yogya Chugh 	Yogya Chugh 	"So while working on a ticket, I came across a strange behaviour that whenever I pass a relative path like './goa.html' to the extends tag that leads to an Attribution error !
I have attached a test case which will pass if error is produced ! You can check it out !
So, I tried to find the reason for this and found:-
When we separately create a `Template` and `Context` class along with calling the `render` method of Template, the error is produced. 

This happens because in such a case the `origin` for the template is None hence, setting it to '<unknown source>' due to this code:-
{{{
#django/template/base.py
if origin is None:
    origin = Origin(UNKNOWN_SOURCE)
}}}
Here, UNKNOWN_SOURCE is global variable with value ""<unknown source>""

So this ain't an issue normally but when we use `{% extends %}` tag, it makes use of a function `construct_relative_path` which is passed the `template name` from `origin` !

The function `construct_relative_path` performs an `lstrip` method on the template leading to error in case the template's origin is ""<unknown source>"". Because, `origin.template_name` is `None`. And so does the `lstrip` method produces error .

Code Snippet:-
{{{
#django/template/loader_tags.py
new_name = posixpath.normpath(
        posixpath.join(
            posixpath.dirname(current_template_name.lstrip(""/"")),
            new_name,
        )
    )
}}}

The Error log:-
{{{
Internal Server Error: /
Traceback (most recent call last):
  File ""C:\Users\Lenovo\AppData\Roaming\Python\Python313\site-packages\django\core\handlers\exception.py"", line 55, in inner
    response = get_response(request)
  File ""C:\Users\Lenovo\AppData\Roaming\Python\Python313\site-packages\django\core\handlers\base.py"", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File ""C:\Users\Lenovo\OneDrive\Desktop\djangoplz\new\trial\views.py"", line 9, in index
    temp = Template(temp_string)
  File ""C:\Users\Lenovo\AppData\Roaming\Python\Python313\site-packages\django\template\base.py"", line 154, in __init__
    self.nodelist = self.compile_nodelist()
                    ~~~~~~~~~~~~~~~~~~~~~^^
  File ""C:\Users\Lenovo\AppData\Roaming\Python\Python313\site-packages\django\template\base.py"", line 196, in compile_nodelist
    nodelist = parser.parse()
  File ""C:\Users\Lenovo\AppData\Roaming\Python\Python313\site-packages\django\template\base.py"", line 518, in parse
    raise self.error(token, e)
  File ""C:\Users\Lenovo\AppData\Roaming\Python\Python313\site-packages\django\template\base.py"", line 516, in parse
    compiled_result = compile_func(self, token)
  File ""C:\Users\Lenovo\AppData\Roaming\Python\Python313\site-packages\django\template\loader_tags.py"", line 293, in do_extends
    bits[1] = construct_relative_path(parser.origin.template_name, bits[1])
              ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File ""C:\Users\Lenovo\AppData\Roaming\Python\Python313\site-packages\django\template\loader_tags.py"", line 258, in construct_relative_path
    posixpath.dirname(current_template_name.lstrip(""/"")),
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'lstrip'
}}}

This error is produced on both `5.1.7` version and on the `dev` too !

I would love to work on this ! Please do review"	Bug	closed	Template system	dev	Normal	fixed	extends		Ready for checkin	1	0	0	0	0	0