bug#19258: 24.3; Python Mode breaks self-insert-command

bug#19258: 24.3; Python Mode breaks self-insert-command

[Taylor R Campbell]

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':


Open a file named foo.py.  Enter the following text:

    f = (
    if y[]

Then put the point between the square brackets and type `i', a key
which is bound to self-insert-command.  Instead of simply inserting an
`i' as I asked, the whole line will jump to the right several spaces.

This happens because Python Mode has incorrectly put a function into
`post-self-insert-hook' that randomly messes with the buffer.  There
is no reason Python Mode should touch `post-self-insert-hook' at all
unless I intentionally turn on `electric' nonsense, which I do not do.


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 11.0.11501000
System Description:	Ubuntu 14.04.1 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_GB.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Python

Minor modes in effect:
  diff-auto-refine-mode: t
  shell-dirtrack-mode: t
  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
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:

Recent messages:

Load-path shadows:
/usr/share/emacs/24.3/site-lisp/debian-startup hides /usr/share/emacs/site-lisp/debian-startup
/usr/share/emacs/site-lisp/rst hides /usr/share/emacs/24.3/lisp/textmodes/rst

Features:
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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 pp cus-edit wid-edit find-func apropos
dabbrev compare-w tabify cus-start cus-load etags novice diff-mode
easy-mmode diff add-log sh-script smie executable make-mode scheme dired
face-remap sort mule-util shell pcomplete grep misearch multi-isearch
help-mode uniquify advice help-fns advice-preload python rx vc-git
cc-langs cl cl-lib cc-mode cc-fonts easymenu cc-guess cc-menus cc-cmds
cc-styles cc-align cc-engine cc-vars cc-defs pylint compile comint
ansi-color ring haskell-mode-autoloads edmacro kmacro 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)

bug#19258: 24.3; Python Mode breaks self-insert-command

[Stefan Monnier]

Version: 24.4

> Open a file named foo.py.  Enter the following text:

>     f = (
>     if y[]

> Then put the point between the square brackets and type `i', a key
> which is bound to self-insert-command.  Instead of simply inserting an
> `i' as I asked, the whole line will jump to the right several spaces.

That was fixed in 24.4

> This happens because Python Mode has incorrectly put a function into
> `post-self-insert-hook' that randomly messes with the buffer.  There
> is no reason Python Mode should touch `post-self-insert-hook' at all
> unless I intentionally turn on `electric' nonsense, which I do not do.

Thanks for the lecture ;-)


        Stefan