bug#18959: 25.0.50; vc-change-log displays "show 2x entries" even when none available

[Lars Ingebrigtsen <larsi@gnus.org>]

Tom Tromey <tom@tromey.com> writes:

> I did "C-x v l" on a file with 5 revisions.
> They all appear in *vc-change-log*.
>
> At the bottom I see two buttons:
>
>     Show 2X entries    Show unlimited entries
>
> First, there aren't any more entries, so showing these buttons is
> confusing.  That's somewhat understandable but it would be nice if it
> didn't do that.

(I'm going through old bug reports that unfortunately got no response at
the time.)

It would be -- and this behaviour is still present in Emacs 28.  But I
guess the problem is that we don't really know how many revisions there
are?

On the other hand, we know how many revisions we asked for, and we know
how many we got.  So if we asked for 2000 revisions, and got 5
revisions, then displaying those buttons is probably not necessary?  And
that sounds like something that should be easy to implement.  (If we
asked for 2000 and got 2000, then we don't know, and we'll probably get
a bug report on that, too, but whatevs).

I've now done this on the trunk, and it seem to work OK in my repos.
More testing in non-git VCs would be nice.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no