bug#1301: previous-single-char-property-change on string with no match returns string end

[Tim Toolan]

When searching a string using previous-single-char-property-change, and no
change is found, it returns the maximum valid position in object, instead
of the minimum valid position in object as stated in the emacs lisp manual.

This can be reproduced by the following lisp statement, which returns 10
instead of 0.

(previous-single-char-property-change 10 'display "0123456789")


In GNU Emacs 22.2.1 (x86_64-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2008-06-12 on aquarius
Windowing system distributor `The X.Org Foundation', version 11.0.10300000
configured using `configure  '--prefix=/usr' '--host=x86_64-pc-linux-gnu' 
'--mandir=/usr/share/man' '--infodir=/usr/share/info' '--datadir=/usr/share' 
'--sysconfdir=/etc' '--localstatedir=/var/lib' '--program-suffix=-emacs-22' 
'--infodir=/usr/share/info/emacs-22' '--without-carbon' '--with-sound' 
'--with-x' '--with-toolkit-scroll-bars' '--with-jpeg' '--with-tiff' 
'--with-gif' '--with-png' '--with-xpm' '--with-x-toolkit=athena' 
'--without-gtk' '--without-hesiod' '--with-kerberos' '--with-kerberos5' 
'--libdir=/usr/lib64' '--build=x86_64-pc-linux-gnu' 
'build_alias=x86_64-pc-linux-gnu' 'host_alias=x86_64-pc-linux-gnu' 
'CFLAGS=-march=nocona -pipe -O2' 'LDFLAGS=''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: C
  locale-coding-system: nil
  default-enable-multibyte-characters: t

Major mode: Emacs-Lisp

Minor modes in effect:
  show-paren-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  auto-compression-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
M-x r e p o r t <tab> <return>

Recent messages:
Warning: no fonts matching `-*-fixed-medium-r-normal-*-16-*-*-*-*-*-iso8859-1' 
available [2 times]
("emacs" "pscpc.el")
Loading paren...done
Loading /usr/share/emacs/site-lisp/auctex/tex-site.el (source)...done
Loading /u/staff/toolan/.emacs.d/auxlabel.el (source)...done
Loading /u/staff/toolan/.emacs.d/auxlabel.el (source)...done
For information about GNU Emacs and the GNU system, type C-h C-a.
Loading emacsbug...
Loading regexp-opt...done
Loading emacsbug...done