Subject: bug#20440: reproducible recipe

From: Sho Takemori <[email-masked]>
Date: Fri, 11 Sep 2015 17:57:32 +0900

> Is this a real buffer corruption, or just the display corruption?

It is a real buffer corruption. I made the second gist by C-x h, M-w and
pasting it to the browser.
If I change the size of the frame or the window configuration, I still have
a corrupted buffer.

> Also, how do you invoke Emacs to reproduce the problem?

By evaluating the code in the first gist.

I use emacs-jedi (https://github.com/tkf/emacs-jedi). So does the original
reporter.
Since the problem occurs frequently, I can find strings file-content1 and
file-content2 in the first gist.
As for the function my/add-to-after-change-functions, I looked into the
source of emacs-jedi and wrote a similar code.

> Finally, does the problem go away if you set your locale to something
> else, like en_US.UTF-8?

No. I can also reproduce it in the live session of Xubuntu 14.04, where
LANG=en_US.UTF-8.
Here is the output of M-x report-emacs-bug in Emacs 24.3 in the live
session.

----------------------------------------------------------------------
From: Live session user
<[email-masked]>
To: [email-masked]
Subject: 24.3; revert-buffer
--text follows this line--
This bug report will be sent to the Bug-GNU-Emacs mailing list
and the GNU bug tracker at debbugs.gnu.org.  Please check that
the From: line contains a valid email address.  After a delay of up
to one day, you should receive an acknowledgment at that address.

Please write in English if possible, as the Emacs maintainers
usually do not have translators for other languages.

Please describe exactly what actions triggered the bug, and
the precise symptoms of the bug.  If you can, give a recipe
starting from `emacs -Q':

If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
For information about debugging Emacs, please read the file
/usr/share/emacs/24.3/etc/DEBUG.

In GNU Emacs 24.3.1 (x86_64-pc-linux-gnu, GTK+ Version 3.10.7)
 of 2014-03-07 on lamiak, modified by Debian
Windowing system distributor `The X.Org Foundation', version 11.0.11600000
System Description:    Ubuntu 14.04.2 LTS

Configured using:
 `configure '--build' 'x86_64-linux-gnu' '--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/emacs24:/etc/emacs:/usr/local/share/emacs/24.3/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.3/site-lisp:/usr/share/emacs/site-lisp'
 '--with-crt-dir=/usr/lib/x86_64-linux-gnu' '--with-x=yes'
 '--with-x-toolkit=gtk3' '--with-toolkit-scroll-bars'
 'build_alias=x86_64-linux-gnu' 'CFLAGS=-g -O2 -fstack-protector
 --param=ssp-buffer-size=4 -Wformat -Werror=format-security -Wall'
 'LDFLAGS=-Wl,-Bsymbolic-functions -Wl,-z,relro'
 'CPPFLAGS=-D_FORTIFY_SOURCE=2''

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Python

Minor modes in effect:
  tooltip-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 input:
<help-echo> <help-echo> C-y M-x e v a l - b u <tab>
<return> M-x r e p o r t - e m a c s - b u <tab> <
return>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Mark set
Can't guess python-indent-offset, using defaults: 4 [2 times]
or: Assertion failed: (string= (buffer-string) file-content2)

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util
mail-prsvr mail-utils python rx easymenu comint ring ansi-color cl-macs
gv cl-lib time-date tooltip ediff-hook vc-hooks lisp-float-type mwheel
x-win x-dnd tool-bar dnd fontset image regexp-opt fringe tabulated-list
newcomment lisp-mode register page menu-bar rfn-eshadow timer select
scroll-bar mouse jit-lock font-lock syntax facemenu font-core frame cham
georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese hebrew greek romanian slovak czech european ethiopic
indian cyrillic chinese case-table epa-hook jka-cmpr-hook help simple
abbrev minibuffer loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote make-network-process
dbusbind dynamic-setting system-font-setting font-render-setting
move-toolbar gtk x-toolkit x multi-tty emacs)
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