emacs 21.1 writes invalidly encoded ISO-2022-JP-2 files

[Bruno Haible]

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In GNU Emacs 21.1.1 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2001-10-28 on linuix
configured using `configure  --prefix=/packages/gnu'
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: POSIX
  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: de_DE
  locale-coding-system: iso-latin-1
  default-enable-multibyte-characters: t

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

I started editing an ASCII file, adding several ISO-8859-1:GR
characters and copy&pasting from xterm a Unicode arrow character
(produced via "/usr/bin/printf '\u2191'"). When saving the file, emacs
told me that the encoding mule-utf-8-unix was not suitable for the
file contents (very astonishing and inconvenient). So I chose to save
in iso-2022-jp-2, and then attempted to convert to UTF-8 using GNU
libiconv's "iconv" program. It failed:

$ iconv -f ISO-2022-JP-2 -t UTF-8 < de.po > /dev/null 
iconv: (stdin): cannot convert

$ iconv --version
iconv (GNU libiconv 1.7)
Copyright (C) 2000-2002 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Written by Bruno Haible.

The reason is that the saved file (de.po, attached) is in fact
invalid. It contains in line 22 a G2 designation for ISO-8859-1 (ESC
. A) and a use of it (ESC N ;), and later in line 27 a use of G2 (ESC
N ;) without prior designation on the same line. But the document
which defines ISO-2022-JP-2, RFC 1554, says:

   At the beginning of a line, information on G2 designation of the
   previous line is cleared.  New designation must be given before a
   character in 96 character sets is used in the line.


Recent input:
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<menu-bar> <help-menu> <report-emacs-bug>

Recent messages:
(emacs)
Loading disp-table...done
Loading tool-bar...done
Loading image...done
Loading tooltip...done
Loading cl-indent...done
Loading derived...done
For information about the GNU Project and its goals, type C-h C-p.
Loading emacsbug...done

de.po
Description: de.po