Zle redisplay bug in pws-24

Zle redisplay bug in pws-24

[Bart Schaefer]

It's probably present in other versions too ... yup, 3.0.6-pre-5 has it ..

It happens with a multiline buffer, and appears to have something to do with
killing a line that is exactly one character shorter than the width of the
terminal.  Here's how I reproduced it:

Start with a prompt string that's ten characters long (e.g. "zagzig<2> " was
mine at the time).  In netscape, go to article 6850 in the zsh-workers
archive; drag-select the patch at the end (from "---" through "sleep(1);").
Back in your zsh terminal, start a here-document ("patch -p0 -R <<'EOF'")
and then paste in the text.  Finish with EOF and hit return.  Note that
the patch fails because of whitespace differences (sigh).  Hit ctrl-P to
call back the here-document and move up to edit the "patch" line.  Decide
that's not what you want to do after all and idly begin tapping ctrl-K
until you see:

zagzig<2>             while ((ttpgrp = gettygrp()) != -1 && ttpgrp != mypgrp) {
                sleep(1);

EOF

The cursor at this moment is right after the prompt.  Hit ctrl-K again and
you see (cursor represented by an underscore):

          _
zagzig<7>       sleep(1);                                                      
                
EOF

Whoops, the prompt moved down to the "sleep(1);" line, but the cursor is
still on the line above it!

-- 
Bart Schaefer                                 Brass Lantern Enterprises
http://www.well.com/user/barts              http://www.brasslantern.com

Re: Zle redisplay bug in pws-24

[Geoff Wing]

Bart Schaefer <schaefer@candle.brasslantern.com> typed:
[...stuff deleted...]
:and appears to have something to do with killing a line that is exactly
:one character shorter than the width of the terminal.
[...stuff deleted...]

My brain must be malfunctioning for me to have spent ages on the wrong track
after being misled by this.

This is the simple patch.  I doubt the super optimised version would be
worth the complexities involved.

*** Src/Zle/zle_refresh.c.org	Sun Jun 20 22:36:14 1999
--- Src/Zle/zle_refresh.c	Mon Jun 28 06:11:09 1999
***************
*** 495,501 ****
      /* if old line and new line are different,
         see if we can insert/delete a line to speed up update */
  
! 	if (ln < olnct - 1 && !(hasam && vcs == winw) &&
  	    nbuf[ln] && obuf[ln] &&
  	    strncmp(nbuf[ln], obuf[ln], 16)) {
  	    if (tccan(TCDELLINE) && obuf[ln + 1] && obuf[ln + 1][0] &&
--- 495,501 ----
      /* if old line and new line are different,
         see if we can insert/delete a line to speed up update */
  
! 	if (ln > 0 && ln < olnct - 1 && !(hasam && vcs == winw) &&
  	    nbuf[ln] && obuf[ln] &&
  	    strncmp(nbuf[ln], obuf[ln], 16)) {
  	    if (tccan(TCDELLINE) && obuf[ln + 1] && obuf[ln + 1][0] &&

-- 
Geoff Wing : <gcw@pobox.com>     Work URL: http://www.primenet.com.au/
Rxvt Stuff : <gcw@rxvt.org>      Ego URL : http://pobox.com/~gcw/
Zsh Stuff  : <gcw@zsh.org>       Phone   : (Australia) 0413 431 874