Re: [GUI emacs:term.el] Possible regression causes word wrapping to break term display in zsh

[Eli Zaretskii <eliz@gnu.org>]

> From: Nicholas Ochiel <nochiel@gmail.com>
> Date: Sat, 26 Nov 2016 13:29:48 +0300
> Cc: Dan Nicolaescu <dann@ics.uci.edu>, emacs-devel@gnu.org
> 
> > The discussion there seems to say it has to do with something called
> oh-my-zsh and/or multi-term?
> 
> Indeed, yes, oh-my-zsh (http://ohmyz.sh), which provides plugins for
> zsh appears to be the source of the problem. (I apologise for not
> investigating that a bit more before posting.)
> 
> Specifically, by disabling the plugin which provides *syntax
> highlighting* in the shell,
> (https://github.com/zsh-users/zsh-syntax-highlighting), ~ emacs -Q
> --eval '(term "/bin/zsh")' ~ works without error.
> 
> (However, the syntax highlighting plugin works without any issues in xterm.)

I hope you are aware of the significant difference between any
terminal emulator and an Emacs terminal emulator.  Where the former
can rely on the terminal device driver to perform certain commands
sent by the shell, Emacs must reproduce all of those features in Lisp
code, and convert each command to the equivalent Emacs commands to
move the cursor, insert or delete text, change color of the text, etc.

> I've provided further details below in case they are still relevant.

Thanks.  I think the reason is that term.el's ANSI sequence handler is
simply unprepared to deal with the complex commands this plug-in
causes zsh to send.  As result, term.el becomes confused when text
deletion and reinsertion happen at the end of the screen line.
Patches to term.el to support that are welcome.