bug#22048: 25.1; frame title vanishes when speedbar present

[Eli Zaretskii <eliz@gnu.org>]

> From: David Reitter <david.reitter@gmail.com>
> Date: Mon, 30 Nov 2015 11:20:00 -0500
> Cc: 22048@debbugs.gnu.org,
>  konrad.podczeck@univie.ac.at
> 
> > 
> > I'm afraid I don't follow: why does ns_set_name_as_filename need the
> > buffer to be the current buffer?  It access that buffer through the
> > frame pointer:
> 
> Yes, but x_implicitly_set_name reads Vframe_title_format directly:
> 
> if (FRAME_NS_P (f) && ((FRAME_ICONIFIED_P (f) && EQ (Vicon_title_format, Qt))
>                          || EQ (Vframe_title_format, Qt)))
> 
> It picks up the wrong value there.  Based on that, I think ns_set_name_as_filename isn’t called at all because it reads the value meant for the speedbar frame. I didn’t bother to look at what then happens in ns_set_name and ns_set_name_internal.

Sorry, I'm still confused: Vframe_title_format is a global variable,
it's neither buffer-local not frame-local, AFAIK.  So how come the
wrong value is picked up by x_implicitly_set_name?

> (By the way, I first tried to do this in x_implicitly_set_name:
> 
> set_buffer_internal_1
> 	(XBUFFER (XWINDOW (f->selected_window)->contents));
> 
> which works, but I find that the more dangerous change as the current buffer is permanently changed.

Not sure how the current buffer enters the picture here.