bug#34224: 25.1; ansi-term displays garbage on tree(1) command

[Marvin Gülker]

The ansi-term (and likewise, term) modes fail to properly display the
Unicode drawing characters used by the tree(1) command. Steps to
reproduce:

1. Run M-x ansi-term
2. Switch to the directory you want to tree(1)
3. Execute tree command
4. The output looks like this:

    testtree
    0tqq Ba
    0tqq Bb
    0x   tqq Bb-a
    0x   mqq Bb-b
    0mqq Bc

Whereas it should look like this:

    testtree
    ├── a
    ├── b
    │   ├── b-a
    │   └── b-b
    └── c

This is on Debian Linux using the GUI emacs.



In GNU Emacs 25.1.1 (x86_64-pc-linux-gnu, GTK+ Version 3.22.11)
 of 2017-09-15, modified by Debian built on trouble
Windowing system distributor 'The X.Org Foundation', version 11.0.11902000
System Description:     Debian GNU/Linux 9.7 (stretch)

Configured using:
 'configure --build x86_64-linux-gnu --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/lib
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes
 
--enable-locallisppath=/etc/emacs25:/etc/emacs:/usr/local/share/emacs/25.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/25.1/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --build x86_64-linux-gnu --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/lib
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes
 
--enable-locallisppath=/etc/emacs25:/etc/emacs:/usr/local/share/emacs/25.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/25.1/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --with-x=yes --with-x-toolkit=gtk3
 --with-toolkit-scroll-bars 'CFLAGS=-g -O2
 -fdebug-prefix-map=/build/emacs25-wN2qS3/emacs25-25.1+1=. 
-fstack-protector-strong
 -Wformat -Werror=format-security -Wall' 'CPPFLAGS=-Wdate-time
 -D_FORTIFY_SOURCE=2' LDFLAGS=-Wl,-z,relro'

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GCONF GSETTINGS
NOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11

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

Major mode: Term

Minor modes in effect:
  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

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message dired format-spec rfc822 mml
mml-sec password-cache epg epg-config gnus-util mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
rfc2047 rfc2045 ietf-drums mm-util help-fns help-mode cl-loaddefs pcase
cl-lib mail-prsvr mail-utils term disp-table easymenu ehelp ring
time-date mule-util tooltip eldoc electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel x-win term/common-win x-dnd tool-bar dnd fontset
image regexp-opt fringe tabulated-list newcomment elisp-mode lisp-mode
prog-mode register page menu-bar rfn-eshadow timer select scroll-bar
mouse jit-lock font-lock syntax facemenu font-core 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 charscript case-table epa-hook
jka-cmpr-hook help simple abbrev 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 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 90204 7403)
 (symbols 48 20271 0)
 (miscs 40 53 146)
 (strings 32 15590 4312)
 (string-bytes 1 444050)
 (vectors 16 12487)
 (vector-slots 8 438436 6828)
 (floats 8 164 11)
 (intervals 56 329 17)
 (buffers 976 19))