bug#20810: 25.0.50; tabulated-list is broken

[Artur Malabarba]

>> I can't reproduce that. Could you try emacs -Q?
>
> Hmm, I did a "git pull" and recompiled everything, and the problem is
> gone for me with the `buffer-menu' command. But it still remains for
> `debbugs-gnu'.

Ok, I confirm I have it for debbugs as well.

> The second argument s2 of `debbugs-gnu-sort-id' is (nil nil), which
> doesn't look like a valid sort item.

Indeed.

> Does `tabulated-list-print' calls the
> sort function with possibly incorrect items? Or is there an incompatible
> change?

Answer to both of these should be "no", but clearly at least one
isn't. :-) I'm looking into it.

> etc/NEWS mentions a change of `tabulated-list-print', but I don't
> see how it is related to the problem.

As part of that change, the sorting logic got refactored a bit, so I
probably messed it up. It doesn't really have anything to do with the
new printing method that's actually announced in the news.