This is a misreading of the documentation. object itself, the base class of all objects, does not and never has had __enter__ and __exit__ methods.

The entire page uses "object" to refer to some generic object, e.g. the section on Emulating numeric types uses "object" to refer to something that emulates a numeric value. In this section, "object" refers to any arbitrary object whose type defines the two __enter__ and __exit__ methods, which makes it a context manager.

In hindsight we should have called the base class Object, to avoid ambiguity between arbitrary objects or instances, and the base class object.

In this case I suggest we change the documentation to use "instance" instead of "object" for the entire page, not just the context manager section.

Would it be a good idea to also add positional-only markers, to indicate that the names are conventions and don’t necessarily need to match the docs?

In this case I suggest we change the documentation to use "instance" instead of "object" for the entire page, not just the context manager section.

That might require updating a lot of links across the rest of CPython's documentation.

Yes, I agree that it might make the data model documentation less confusing if we referred to dunders as instance.__await__, instance.__enter__, etc.

My point is that a lot of links to these methods from other parts of the documentation might be broken if the data model docs were reworked in this way. For example, there are currently six other docs files in the CPython repo that link to the datamodel docs on object.__class_getitem__. I think we might have to update all of those links if we started calling it instance.__class_getitem__ instead.

a lot of links to these methods from other parts of the documentation might be broken

A lot of links from other parts of the internet, too, for example from Stack Overflow. Is there no way to have anchors for both or to redirect the old links?

Is there no way to have anchors for both or to redirect the old links?

I'm not sure. @CAM-Gerlach might know more :)

But if we're talking about updating the whole page for the datamodel docs so that all dunders are referred to as instance.__dunder__, we'd presumably have to implement those redirects for every single dunder method.

A lot of links from other parts of the internet, too, for example from Stack Overflow. Is there no way to have anchors for both or to redirect the old links?

We can redirect external links by creating a ref target label that matches the old anchor pointing to the relevant object, which is only one line per method. That won't for internal links using :meth:/:func:, though; those can be updated here, but it will break other docs sites linking to them via intersphinx (though it will generate a warning with -n, and visibly display as unlinked in the rendered docs).