views.Feed methods cannot be decorated

[Germano Gabbianelli]

If one applies a decorator on a method which is called by __get_dynamic_attr a TypeError like this occurs:

Exception Type: TypeError at /blog/feed/
Exception Value: item_link() takes exactly 2 arguments (1 given)

I think this is because __get_dynamic_attr tries to count the function's arguments, but decorators usally get defined with the *args, **kwargs syntax, so this trick does not work here.

            if code.co_argcount == 2:       # one argument is 'self'
                return attr(obj)
            else:
                return attr()

I think the best approach would be to remove one of the two methods. IMHO We should have either attr(item) or attr() not both, as "there should be one, and preferably only one, obvious way to do it".

[Aymeric Augustin]

Yes, that code is fragile.

[coldmin]

I reproduced it. I'm working now on fix.

[coldmin]

sample project, which show how patch works now

[coldmin]

I sended pull request.
​https://github.com/django/django/pull/2584

The problem is that methods without the 'item' argument (only with self) should be static now:

    @staticmethod
    def item_description(self):
        return force_text(item)

But the decorators works now (sample project is in attachments)

[Marcelo Galigniana]

Pull Request created: ​PR

[Mariusz Felisiak <felisiak.mariusz@…>]

In 241fe59b:

Refs #22078 -- Added syndication test for feeds with callable objects.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 7e4656e4:

Refs #22078 -- Added syndication test for feeds with static methods.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 9d3b8120:

[4.1.x] Refs #22078 -- Added syndication test for feeds with static methods.

Backport of 7e4656e4b2189390a433a149091442d53a777e2b from main.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 8c0886b0:

Fixed #22078 -- Fixed crash of Feed with decorated methods.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 0210dbcb:

[4.1.x] Fixed #22078 -- Fixed crash of Feed with decorated methods.

Backport of 8c0886b068ba4e224dd78104b93c9638b860b398 from main.