23.0.60; GNU Emacs does not handle composed characters

[Peter Dyballa]

Hello!

When pasting a copy of a filled in text from OmniWeb (a Web browser  
coming from the NeXT) into a file buffer in GNU Emacs (mode-line  
starts with -U:), which was launched with -Q, the German umlauts ä,  
ö, ü, Ä, Ö, Ü are stripped off their diaereses and mutate to a, o, u,  
A, O, U. Typing C-u C-x = on such a Marcel Duchamps character leads  
to an error message in echo area:

        Format specifier doesn't match argument type

In *Messages* buffer a ``describe-char: ´´is prepended the text.

In dired buffers the same umlauts in file names are stripped, while  
the date fields can display an abbreviated month's name as ``Mär´´.  
Typing on this ä C-c C-x = I get:

                character: ä (228, #o344, #xe4)
        preferred charset: iso-8859-1 (Latin-1 (ISO/IEC 8859-1))
               code point: 0xE4
                   syntax: w    which means: word
                 category: j:Japanese l:Latin
              buffer code: #xC3 #xA4
                file code: #xC3 #xA4 (encoded by coding system utf-8-unix)
                  display: by this font (glyph code)
	     -B&H-LucidaTypewriter-Medium-R-Normal-Sans-10-100-75-75-M-60- 
ISO8859-1 (#xE4)
        
        Character code properties are not shown: customize what to show
        
        There are text properties here:
          auto-composed        t
          fontified            t

instead of an error message. The error message is output when I type  
on as tripped umlaut in a file name!


Looking with GNU Emacs 23.0.50 into the file saved with its stripped  
umlauts I see instead of them ``{äöüÄÖÜ}<an open box>´. This box is  
described in GNU Emacs 23.0.50 as:

                character:  (332488, #o1211310, #x512c8, U+0308)
                  charset: mule-unicode-0100-24ff
                           (Unicode characters of the range U+0100..U+24FF.)
               code point: #x25 #x48
                   syntax: w    which means: word
                 category: ^:Combining diacritic or mark
              buffer code: #x9C #xF4 #xA5 #xC8
                file code: #xCC #x88 (encoded by coding system mule-utf-8-unix)
                  display: by this font (glyph code)
	     -b&h-lucida sans typewriter-medium-r-normal--10-98-74-74-m-60- 
iso10646-1 (#x308)
             Unicode data:
                     Name: COMBINING DIAERESIS
                 Category: non-spacing mark
          Combining class: Above
            Bidi category: Non-Spacing Mark
                 Old name: NON-SPACING DIAERESIS
        ISO 10646 comment: Dialytika


In GNU Emacs 23.0.60.1 (powerpc-apple-darwin8.11.0, GTK+ Version 2.6.10)
 of 2007-12-25 on Latsche.local
Windowing system distributor `The XFree86 Project, Inc', version  
11.0.40400000
configured using `configure  '--enable-font-backend' '--with-x- 
toolkit=gtk' '--with-dbus' '--without-sound' '--without-pop' '--with- 
xpm' '--with-jpeg' '--with-tiff' '--with-gif' '--with-png' '--enable- 
locallisppath=/Library/Application Support/Emacs/calendar22:/Library/ 
Application Support/Emacs/caml:/Library/Application Support/Emacs:/sw/ 
share/emacs21/site-lisp/elib' 'PKG_CONFIG_PATH=/sw/lib/freetype219/ 
lib/pkgconfig:/sw/lib/fontconfig2/lib/pkgconfig:/sw/lib/pkgconfig:/sw/ 
lib/system-openssl/lib/pkgconfig:/sw/share/pkgconfig:/usr/lib/ 
pkgconfig:/usr/local/lib/pkgconfig:/usr/local/clamXav/lib/pkgconfig:/ 
usr/local/lib/pkgconfig' 'CPPFLAGS=-no-cpp-precomp -D__BIND_NOSTATIC - 
I/usr/include/openssl -I/sw/include/pango-1.0 -I/sw/lib/fontconfig2/ 
include -I/sw/lib/freetype219/include -I/sw/lib/freetype219/include/ 
freetype2 -I/sw/include -I/usr/local/include -idirafter /usr/X11R6/ 
include' 'CXXFLAGS=-no-cpp-precomp -I/usr/include/openssl -I/sw/ 
include/pango-1.0 -I/sw/lib/fontconfig2/include -I/sw/lib/freetype219/ 
include -I/sw/lib/freetype219/include/freetype2 -I/sw/include -I/usr/ 
local/include' 'CFLAGS=-ggdb -g3 -gfull -H -bind_at_load -pipe -fPIC - 
mcpu=7450 -mtune=7450 -O0' 'LDFLAGS=-dead_strip -multiply_defined  
suppress -L/sw/lib/ncurses -L/sw/lib/fontconfig2/lib -L/sw/lib/ 
freetype219/lib -L/sw/lib -L/usr/local/lib -L/usr/X11R6/lib''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: de_DE.UTF-8
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: de_DE.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t

Major mode: Fundamental

Minor modes in effect:
  tooltip-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-compression-mode: t
  line-number-mode: t

Recent input:
<down-mouse-1> <mouse-1> C-x C-f D a t e i <return>
<down-mouse-2> <mouse-2> <down-mouse-1> <mouse-1> C-x


--
Greetings

  Pete

America believes in education: the average professor earns more money  
in a year than a professional athlete earns in a whole week.
                                ­ Evan Esar