Re: Readline fencepost error with long prompt

[Chet Ramey]

Andreas Schwab wrote:
> Configuration Information [Automatically generated, do not change]:
> Machine: powerpc
> OS: linux-gnu
> Compiler: gcc
> Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='powerpc' 
> -DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='powerpc-suse-linux-gnu' 
> -DCONF_VENDOR='suse' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL 
> -DHAVE_CONFIG_H   -I.  -I. -I./include -I./lib   -O2 -g
> uname output: Linux igel 2.6.30-rc3 #5 SMP Thu Apr 23 11:56:14 CEST 2009 
> ppc64 ppc64 ppc64 GNU/Linux
> Machine Type: powerpc-suse-linux-gnu
> 
> Bash Version: 4.0
> Patch Level: 17
> Release Status: release
> 
> Description:
>       If the length of $PS1 exactly matches the screen width and it ends
>       in invisible characters the cursor is placed to far to the right
>       by the number of invisible characters.
> 
> Repeat-By:
>       $ PS1="$(printf %80s .)\[\033[m\]"

Try the attached patch.  It should fix the problem without introducing any
regressions.

Chet
-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer

Chet Ramey, ITS, CWRU    chet@case.edu    http://cnswww.cns.cwru.edu/~chet/

*** ../bash-4.0-patched/lib/readline/display.c  2009-01-04 14:32:32.000000000 
-0500
--- lib/readline/display.c      2009-04-25 21:42:18.000000000 -0400
***************
*** 1893,1896 ****
--- 1895,1902 ----
    woff = WRAP_OFFSET (_rl_last_v_pos, wrap_offset);
    cpos = _rl_last_c_pos;
+ 
+   if (cpos == 0 && cpos == new)
+     return;
+ 
  #if defined (HANDLE_MULTIBYTE)
    /* If we have multibyte characters, NEW is indexed by the buffer point in
***************
*** 1906,1912 ****
         desired display position. */
        if ((new > prompt_last_invisible) ||            /* XXX - don't use woff 
here */
!         (prompt_physical_chars > _rl_screenwidth &&
           _rl_last_v_pos == prompt_last_screen_line &&
!          wrap_offset >= woff &&
           new > 
(prompt_last_invisible-(_rl_screenwidth*_rl_last_v_pos)-wrap_offset)))
           /* XXX last comparison might need to be >= */
--- 1912,1918 ----
         desired display position. */
        if ((new > prompt_last_invisible) ||            /* XXX - don't use woff 
here */
!         (prompt_physical_chars >= _rl_screenwidth &&
           _rl_last_v_pos == prompt_last_screen_line &&
!          wrap_offset >= woff && dpos >= woff &&
           new > 
(prompt_last_invisible-(_rl_screenwidth*_rl_last_v_pos)-wrap_offset)))
           /* XXX last comparison might need to be >= */