bug#33268: 26.1.50; Can't decode the utf-8 text file

[Zhang Haijun]

Open the attachment text file with "emacs -Q". There are many 
unrecognized chars(like \342\200\230). Following is the encoding info of 
the buffer.

-------------------------------------------------
= -- no-conversion (alias: binary)

Do no conversion.

When you visit a file with this coding, the file is read into a
unibyte buffer as is, thus each byte of a file is treated as a
character.
Type: raw-text (text with random binary characters)
EOL type: LF
--------------------------------------------------

But if I run the command revert-buffer, then there is no unrecognized 
chars. Encoding info of the buffer becomes:

---------------------------------------------------
U -- utf-8-unix (alias: mule-utf-8-unix cp65001-unix)

UTF-8 (no signature (BOM))
Type: utf-8 (UTF-8: Emacs internal multibyte form)
EOL type: LF
This coding system encodes the following charsets:
   unicode
---------------------------------------------------



In GNU Emacs 26.1.50 (build 4, x86_64-pc-linux-gnu, GTK+ Version 3.22.26)
  of 2018-11-04 built on centos7.home
Repository revision: 7cadb328092e354225149bbc74c2ddaf4b49b638
Windowing system distributor 'The X.Org Foundation', version 11.0.11905000
Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Quit [3 times]
user-error: Beginning of history; no preceding item
funcall-interactively: End of buffer

Configured using:
  'configure --prefix=/home/jun/apps/emacs-26 --without-makeinfo
  --with-x-toolkit=gtk3 --with-modules'

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND DBUS GSETTINGS GLIB NOTIFY
LIBSELINUX GNUTLS LIBXML2 FREETYPE XFT ZLIB TOOLKIT_SCROLL_BARS GTK3 X11
XDBE XIM MODULES THREADS

Important settings:
   value of $LANG: en_US.UTF-8
   value of $XMODIFIERS: @im=fcitx
   locale-coding-system: utf-8-unix

Major mode: Text

Minor modes in effect:
   diff-auto-refine-mode: t
   tooltip-mode: t
   global-eldoc-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
   auto-composition-mode: t
   auto-encryption-mode: t
   auto-compression-mode: t
   line-number-mode: t
   transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny seq byte-opt gv
bytecomp byte-compile cconv cl-loaddefs cl-lib dired dired-loaddefs
format-spec rfc822 mml mml-sec password-cache epa derived epg epg-config
gnus-util rmail rmail-loaddefs mm-decode mm-bodies mm-encode mail-parse
rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045
ietf-drums mm-util mail-prsvr mail-utils vc-git diff-mode easymenu
easy-mmode elec-pair time-date mule-util tooltip eldoc electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel term/x-win x-win
term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode elisp-mode lisp-mode
prog-mode register page menu-bar rfn-eshadow isearch timer select
scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame cl-generic 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 charscript charprop case-table epa-hook jka-cmpr-hook
help simple abbrev obarray minibuffer cl-preloaded nadvice loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote threads dbusbind inotify dynamic-setting system-font-setting
font-render-setting move-toolbar gtk x-toolkit x multi-tty
make-network-process emacs)

Memory information:
((conses 16 98466 14078)
  (symbols 48 20784 1)
  (miscs 40 42 154)
  (strings 32 29892 1511)
  (string-bytes 1 791061)
  (vectors 16 14723)
  (vector-slots 8 510132 7238)
  (floats 8 51 372)
  (intervals 56 222 0)
  (buffers 992 13)
  (heap 1024 24474 3071))

emacs-26.txt
Description: emacs-26.txt