Subject: bug#23819: 25.0.95; display botched badly in xterm window

From: Eli Zaretskii <[email-masked]>
Date: Thu, 23 Jun 2016 17:53:21 +0300

> Cc: [email-masked]
> From: Paul Eggert <[email-masked]>
> Date: Thu, 23 Jun 2016 10:58:15 +0200
> 
>     Can you modify xterm.el such that it stores the value of 'version' in xterm--version-handler in a variable? Then you could report the values of that variable when you see the problems and when you don't, and maybe we will learn something that way. 
> 
> The version string is "1;3201;0" and the version is therefore computed to be 200, when things work at startup. This corresponds to GNOME Terminal 3.4.1.1 on the client (Ubuntu 12.04.5 LTS). Right now I can't reproduce the problem where the version string is copied into the start of the first buffer (I assume this is because my Internet connection is good right now). However, after doing a lot of searches I can occasionally reproduce the problem where characters are misdisplayed, with 'emacs -Q src/conf_post.h'. I repeatedly type "C-s h a s M-<" with a few extra C-s's thrown in.

Which probably means there are two separate problems.

Actually, what you describe now kinda rings a bell: we had similar
unexplained glitches when TTY menus were introduced.  See bug#17497;
starting with http://debbugs.gnu.org/cgi/bugreport.cgi?bug=17497#230
there are some thoughts about a particular code fragment in cm.c that
never got addressed; perhaps you can dig into this, as you evidently
have access to a system where these problems can be reproduced.

Also, in http://debbugs.gnu.org/cgi/bugreport.cgi?bug=17497#236, you
will see a link to a Virtual Box related discussion where someone
claims Emacs fails to deliver a crucial cursor-motion command to the
TTY driver, for some reason.  At the time, I analyzed many termscript
files people sent from affected machines, and saw no missing commands,
but maybe I missed something.

If you can see the same menu-related glitches, perhaps they will
provide an easier way to reproduce the problem and try solving it.

OTOH, if what you see is the same problem as in bug#17497, then it's
by no means new.

Thanks.