bug#3158: 23.0.92; assertion failure in fontset_find_font

[YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>]

Steps to reproduce:

  1. Compile Emacs with "make CFLAGS='-g -DENABLE_CHECKING'"
  2. emacs -Q
  3. M-x list-charset-chars RET mac-roman RET

Result:

  .../src/fontset.c:551: Emacs fatal error: assertion failed: VECTORLIKEP((rfont_def))

The value of rfont_def is nil when this failure happens.

#3  0x00241da4 in fontset_find_font (fontset=17297828, c=57374, face=0x1054820, id=147, fallback=0) at .../src/fontset.c:551
551		      = FONT_DEF_REPERTORY (RFONT_DEF_FONT_DEF (rfont_def));
(gdb) list
546		   first.  */
547		for (i = 0; i < ASIZE (vec); i++)
548		  {
549		    Lisp_Object rfont_def = AREF (vec, i);
550		    Lisp_Object repertory
551		      = FONT_DEF_REPERTORY (RFONT_DEF_FONT_DEF (rfont_def));
552	
553		    if (XINT (repertory) == id)
554		      {
555			charset_matched = i;
(gdb) call debug_print (rfont_def)
nil
(gdb) call debug_print (vec)
[[nil [#<font-spec nil nil nil nil iso10646-1 nil nil nil nil nil nil nil nil> 142 nil] nil 0] nil]
(gdb) p i
$1 = 1

				     YAMAMOTO Mitsuharu
				mituharu@math.s.chiba-u.ac.jp

In GNU Emacs 23.0.92.1 (powerpc-apple-darwin9.6.0, X toolkit)
 of 2009-04-29 on yamamoto-mitsuharu-no-power-mac-g5.local
Windowing system distributor `The X.Org Foundation', version 11.0.10300000
configured using `configure  '--without-jpeg' '--without-gif' '--without-tiff''

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: ja_JP.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  tool-bar-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-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t