bug#23880: Hyperbole causes frame to widen in Gnus

[Stephen Berman]

On Fri, 1 Jul 2016 13:12:42 -0400 Robert Weiner <address@hidden> wrote:

> On Fri, Jul 1, 2016 at 11:53 AM, Stephen Berman <address@hidden> wrote:
>> DejaVu Sans Mono
>
> I tested your test code on a Mac using the "Menlo" font which is
> derived from DejaVu Sans Mono and it did not change the frame width.
> Are you sure, Hyperbole is the only thing you are loading that changes
> between when it happens and when it doesn't?

I test by starting Emacs with -Q, so the only code loaded beyond what's
in the dumped emacs executable is what is called in the test code,
i.e. Hyperbole and Gnus.

> I am using Emacs 24.0.94 which is pretty new but it sounds like your
> Emacs is even newer, so there may just be a bug there that your Emacs
> state is bringing out.

(I assume you mean 25.0.94.)  I've tested with current builds from the
master and emacs-25 branches (the latter is at 25.0.95), but also with a
build of 25.0.94 as well as a build of the released 24.5, and see the
frame widening all of these.

In my testing I have noticed a couple of things that make a difference:
font size and when the test code is evaluated.  For example, the
widening happens with this font:

-unknown-DejaVu Sans Mono-normal-normal-normal-*-12-*-*-*-m-0-iso10646-1

but not with this one:

-unknown-DejaVu Sans Mono-normal-normal-normal-*-15-*-*-*-m-0-iso10646-1

and the same pattern holds for several other fonts I've tried.  And the
widening only happens when I evaluate the test code in a running Emacs;
if I invoke Emacs like this: `emacs -Q -l test.el', where the file
contains the test code, the widening does not happen.  In both cases, I
have no idea why this makes a difference.

> If you want to troubleshoot more, try to isolate a particular library
> whose loading triggers the problem.  I don't think it is a Hyperbole
> bug.

I don't know if a bug in Hyperbole is causing this, all I can conclude
at the moment is that the combination of Hyperbole, Gnus and particular
fonts result in this problem; it seems likely these combinations are
exposing a bug in Emacs.  I did try versions of my test code that load
an individual Hyperbole file instead of the whole package, and in a few
cases -- hui-select.el, hycontrol.el and wconfig.el -- also observed the
frame widening, though the pattern was not exactly the same as when the
entire package is loaded.  I also tried using Gnus code to insert a
button (since that is what appears to trigger the widening) in a
non-Gnus buffer, but that did not result in the frame widening.

In short, this is a strange problem, and I don't know how to proceed
from here.  I'll try asking for advice on emacs-devel.

Steve Berman