Re: Incorrect cursor position when ZLE_RPROMPT_INDENT=0 (with a fix)

[Roman Perepelitsa <roman.perepelitsa@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 1931 bytes --]

On Sun, May 19, 2019 at 7:05 PM Bart Schaefer <schaefer@brasslantern.com>
wrote:

> We constantly go around on this.  If we un-break it for one terminal
> type it breaks for another.  It's an acknowledged problem that in some
> cases you can't set ZLE_RPROMPT_INDENT=0, that's why the variable
> exists in the first place; if it always worked to set it to zero we'd
> remove it.
>
> All your patch does is remove a test for the value of that variable.
> A more correct change would be to add to the test condition a check
> for whether placing a character in the rightmost column (or the
> rightmost/bottom-most position) causes the terminal to auto-wrap (or
> not) the cursor onto the next line.


At first I thought that on my terminal (GNOME Terminal) there is
auto-wrapping when RPROMPT is written at the very right edge. It can be
seen when I set RPROMPT='%K{red}X' and ZLE_RPROMPT_INDENT=0, which results
in an extra line below the prompt with a red cell on the left. Then, after
some debugging, I realized that it's not my terminal that causes
auto-wrapping but ZSH. zputs(rpromptbuf, shout) at zle_refresh.c:1680
doesn't create that new line even when ZLE_RPROMPT_INDENT=0. The following
ZSH code does. That's why my patch doesn't just disable a condition but
also adjusts vcs after zputs(rpromptbuf, shout).

Do I understand you correctly that prior to my patch ZSH
handled ZLE_RPROMPT_INDENT=0 correctly on terminals that do auto-wrap after
RPROMPT is written, but my patch broke them? If so, could point me to such
a terminal? It would be very helpful. I realize that you've had this
discussion a million times and I appreciate your patience.

What $ZSH_PATCHLEVEL were you testing against?  There was a related
> change committed only a month ago, and there has not been a release in
> the meantime.
>

echo $ZSH_PATCHLEVEL
zsh-5.7.1-77-gfae7c85

My fork is currently 1 commit ahead of zsh-users/zsh on github.

Roman.