Uninformative error if block.super is used inside the block tag of a base template

[Mitar]

If block.super is used inside the block tag of a base template, an uninformative error is thrown:

'BlockNode' object has no attribute 'context'

It is thrown in super method when doing:

render_context = self.context.render_context

I think code should check for missing self.context and throw a more informative exception.

[ANUBHAV JOSHI]

I have added a small patch which raises TemplateSyntaxError.

[Tim Graham]

I would hope there's a more specific way to detect this problem than catching all AttributeErrors. Also TemplateSyntaxError should include a helpful message.

[ANUBHAV JOSHI]

Sure.
I just had a quick look. I'll add a better patch soon.

[ANUBHAV JOSHI]

Changed the position where I handled AttributeError

[Tim Graham]

Rather than try/except, it would probably be better to do:

if not hasattr(self, 'context'):
    raise TemplateSyntaxError(...)

And make the message less definitive (e.g. include the original exception message and add "Did you use {{ block.super }} in a base template?". I am not sure, but there might be other cases where context could be missing so including the original exception could be helpful just in case.

[ANUBHAV JOSHI]

​https://github.com/django/django/pull/2949

[Tim Graham <timograham@…>]

In b1abfb3c59467d0bb088e19be76fc42fcb570835:

Fixed #21707 -- Added helpful error message when using {{ block.super }} in base template.

Thanks mitar for the suggestion.