bug#69718: 29.2; grep japanese-iso-8bit-unix string fails with "grep: illegal byte sequence"

[Akira Shirai]

1. emacs -Q on macOS
2. evaluate (set-language-environment "Japanese")
3. visit the directory where SKK-JISYO.L exists (ex. ~/emacs-29.2/leim/SKK-DIC/ 
)
4. type C-x RET c to run universal-coding-system-argument command, and specify 
japanese-iso-8bit-unix as the coding-system
5. type M-x grep to run grep, and specify "grep --color=auto -nH --null -e 
この辞書は SKK-JISYO.L" as the command-args
  => grep fails with "grep: illegal byte sequence"

On emacs 29.1, the grep runs successfully with the same procedures.
If the command-args is "LANG=C grep --color=auto -nH --null -e この辞書は 
SKK-JISYO.L", the grep runs successfully.



In GNU Emacs 29.2 (build 1, x86_64-apple-darwin23.3.0, NS appkit-2487.40
 Version 14.3 (Build 23D56)) of 2024-01-25 built on F9A6231BCF26.local
Windowing system distributor 'Apple', version 10.3.2487
System Description:  macOS 14.3.1

Configured using:
 'configure --with-ns --without-x --without-compress-install
 --with-gnutls=no'

Configured features:
ACL LIBXML2 MODULES NOTIFY KQUEUE NS PDUMPER SQLITE3 THREADS
TOOLKIT_SCROLL_BARS ZLIB

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Fundamental

Minor modes in effect:
  shell-dirtrack-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  buffer-read-only: t
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media puny rfc822
mml mml-sec password-cache epa derived epg rfc6068 epg-config gnus-util
mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils
mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr
mail-utils face-remap help-mode shell pcomplete thingatpt files-x grep
compile text-property-search comint ansi-osc ansi-color ring dired-aux
dired dired-loaddefs japan-util time-date subr-x cl-loaddefs cl-lib rmc
iso-transl tooltip cconv eldoc paren electric uniquify ediff-hook
vc-hooks lisp-float-type elisp-mode mwheel term/ns-win ns-win
ucs-normalize mule-util term/common-win tool-bar dnd fontset image
regexp-opt fringe tabulated-list replace newcomment text-mode lisp-mode
prog-mode register page tab-bar menu-bar rfn-eshadow isearch easymenu
timer select scroll-bar mouse jit-lock font-lock syntax font-core
term/tty-colors frame minibuffer nadvice seq simple cl-generic
indonesian philippine cham georgian utf-8-lang misc-lang vietnamese
tibetan thai tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek
romanian slovak czech european ethiopic indian cyrillic chinese
composite emoji-zwj charscript charprop case-table epa-hook
jka-cmpr-hook help abbrev obarray oclosure cl-preloaded button loaddefs
theme-loaddefs faces cus-face macroexp files window text-properties
overlay sha1 md5 base64 format env code-pages mule custom widget keymap
hashtable-print-readable backquote threads kqueue cocoa ns multi-tty
make-network-process emacs)

Memory information:
((conses 16 58569 6787)
 (symbols 48 6316 0)
 (strings 32 18079 1823)
 (string-bytes 1 543082)
 (vectors 16 14244)
 (vector-slots 8 280500 7109)
 (floats 8 26 33)
 (intervals 56 785 0)
 (buffers 976 16))