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

[Nicholas Ochiel <nochiel@gmail.com>]

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

> Are zsh and a GUI frame necessary for reproducing this issue?

- zsh is necessary.
- The issue occurs both in gui and virtual console.

> Does the recipe you posted reproduce the
problem in "emacs -Q"?

Reproduced with ~ emacs -Q --eval '(term "/bin/zsh")' ~

> Do you mean point jumps by itself, or do you mean it jumps when you
try moving it with cursor motion keys?  IOW, please describe what
triggers these jumps.

- Type one char at a time until the edge of the frame is reached.
- Type one char; line wraps to the next line.
- Type one char; point moves to line above.

> Did you try to disable the fringes?  Did it help?

Issue still occurs when:
- ~(fringe-mode nil)~
- ~(setq overflow-newline-into-fringe nil)
--
Sincerely,
Nicholas Ochiel


On 26 November 2016 at 12:12, Eli Zaretskii <eliz@gnu.org> wrote:
>> From: Nicholas Ochiel <nochiel@gmail.com>
>> Date: Sat, 26 Nov 2016 02:04:56 +0300
>> Cc: emacs-devel@gnu.org
>>
>> Steps:
>> 0. Open gui emacs in X.
>> 1. M-x term (char mode, /bin/zsh)
>
> Are zsh and a GUI frame necessary for reproducing this issue?
>
>> 2. Enter a long input that causes text to wrap at fringe.
>> 3. Notice that point jumps irregularly.
>
> Do you mean point jumps by itself, or do you mean it jumps when you
> try moving it with cursor motion keys?  IOW, please describe what
> triggers these jumps.
>
>> 4. Move point and attempt to edit some portion of wrapped line in terminal.
>> 5. Notice that prompt or previous terminal output is overwritten in an
>> unpredictable manner.
>> 6. Further operations on text cause unpredictable editing behaviour.
>> 7. This occurs regardless of truncate-lines, visual-line-mode.
>
> Did you try to disable the fringes?  Did it help?
>
>>
>> Reproduced with:
>> - Emacs 24.5.1,
>> - emacs-snapshot 26.0.50.2
>>
>> This odd behaviour was also reported here:
>> 1. https://github.com/syl20bnr/spacemacs/issues/5520
>
> The discussion there seems to say it has to do with something called
> oh-my-zsh and/or multi-term?  Does the recipe you posted reproduce the
> problem in "emacs -Q"?
>
> Thanks.