bug#31169: 26.1; Emacs 26.1 RC1 (gtk) display issues over SSH/X11 with xming/vcxsrv

[Eli Zaretskii <eliz@gnu.org>]

> From: charlie hemlock <charliehemlock@gmail.com>
> Date: Sun, 15 Apr 2018 20:09:42 -0400
> 
> 1. Build emacs 26 RC1 with --with-x-toolkit=gtk3
>      a. confirm builds and runs ok when run local
> 2. Login to windows box, launch ssh -X putty session to linux host with
> emacs 26 installed.  (windows xserver: vcxsrv or xming) 
> 3. emacs -Q
> 4. Emacs does not display correctly. Missing minibuffer, & can't type in buffer.  Compare to attached
> screenshot.

Is this all you see in the Emacs frame?  It looks like a part of a
frame, did you clip the image, perhaps?  If so, please show all of the
frame.

> I can compile Emacs 26.1 RC1 ok, and use it locally on the host fine.
> 
> However, when attempting to ssh -X to host via PuTTY 0.70 and launch  the Emacs gui  (emacs -Q), emacs
> is not displaying correctly. Using Windows xserver program VcXsrv (1.19.6.3).
> 
> See attached screenshot - no default welcome screen, and missing minibuffer too. 

It sounds like Emacs is hung or infloops somewhere.  Does it eat CPU
cycles?  Can you exit it with "C-x C-c" or do you have to kill it by a
signal?  Can you attach GDB to it (on the GNU/Linux side) and show a C
backtrace?  Please do this several times, restarting Emacs each time,
to make sure the backtrace points to the same place.

> I suspect this issue is related to some combination of GTK and
> Xming/VcXsrv, however the behavior does change between Emacs 25.3 and 26.1 RC1, see table below:

To make sure this is related to GTK, could you try building with a
different toolkit, just to see if that build starts as expected?

> Possibly related posts:
>  -
> https://emacs.stackexchange.com/questions/40990/emacs-aborted-core-dumped-centos-7-0-emacs-25-3-please-help
> 
>  - https://bugs.launchpad.net/elementaryos/+bug/1355274
>  - https://bugzilla.gnome.org/show_bug.cgi?id=85715

These don't look related to me, because the problems they describe
existed before Emacs 25, which you say worked OK for you.

Thanks.