Subject: bug#78474: 31.0.50; Wrong char insertion in rxvt

From: Eli Zaretskii <[email-masked]>
Date: Sun, 18 May 2025 12:18:32 +0300

> Date: Sun, 18 May 2025 10:30:01 +0200
> From: Samuel Thibault <[email-masked]>
> Cc: [email-masked], [email-masked], [email-masked]
> 
> Eli Zaretskii, le dim. 18 mai 2025 11:05:49 +0300, a ecrit:
> > > Eli Zaretskii, le dim. 18 mai 2025 08:13:58 +0300, a ecrit:
> > > > > Quoting Samuel: "Emacs, instead of sending a rightward cursor movement
> > > > > (\e[C), sends \009\008 (a tabulation and a leftward cursor movement)"
> > > > 
> > > > If Sébastien or Samuel (or someone else) can help us understand how to
> > > > modify the cost calculations and/or what optimizations of cursor
> > > > motion to avoid when these technologies for the visually impaired are
> > > > used, we could see how to fix this.
> > > 
> > > That is exactly what is written above.
> > 
> > Sorry, I don't understand: what is written above?
> 
> ?
> 
> "Emacs, instead of sending a rightward cursor movement
> (\e[C), sends \009\008 (a tabulation and a leftward cursor movement)"
> 
> that is the optimization that disturbs some terminals such as rxvt or
> vte.

Yes, but what does that mean in general?  Should Emacs refrain from
sending TAB in all the cases?  Are there other characters that should
not be sent for similar reasons?

To modify the code, it is not enough to understand what should be done
in this specific case, we need to better understand the problem and
its various aspects, in order to be able to translate that into code
changes.

Also, I'm a bit confused: you say that sending \009\008 disturbs rxvt
or vte, but the original report seemed to be not about what the
terminals do, but about what that causes to the various software
solutions for the visually impaired.  Can you please tell more about
this to resolve the confusion?

Thanks.