bug#19940: 25.0.50; Infinite loop in `studlify-word' with Subword mode

[Simen Heggestøyl]

An infinite loop occurs when Subword mode is active and

`studlify-word' is run on a word with more than one subword. The bug

seems to have been introduced by changes made to subword.el in commit

6ddc44225e743e2b2a0d5c192f50aefd7a4a915b.

Here is a recipe that triggers the bug, starting from emacs -Q:

  1. Open a new buffer, and type in "subWord".

  2. Activate Subword mode by `M-x subword-mode'.

  3. Move point to the beginning of the line, and run `M-x

     studlify-word'.

In GNU Emacs 25.0.50.2 (x86_64-unknown-linux-gnu, GTK+ Version 3.14.5)

 of 2015-02-24 on x240

Repository revision: 450bebaec94611f0958e13e35faf494e17931f8e

Windowing system distributor `The X.Org Foundation', version 11.0.11604000

System Description: Debian GNU/Linux 8.0 (jessie)

Configured using:

 `configure --without-makeinfo'

Configured features:

XPM JPEG TIFF GIF PNG SOUND DBUS GSETTINGS NOTIFY LIBXML2 FREETYPE XFT

ZLIB

Important settings:

  value of $LANG: en_US.UTF-8

  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

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

Recent messages:

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

Load-path shadows:

None found.

Features:

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rfc822 mml easymenu mml-sec mm-decode mm-bodies mm-encode mail-parse

rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045

ietf-drums mm-util help-fns mail-prsvr mail-utils time-date tooltip

eldoc electric uniquify ediff-hook vc-hooks lisp-float-type mwheel x-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 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 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 make-network-process dbusbind

gfilenotify dynamic-setting system-font-setting font-render-setting

move-toolbar gtk x-toolkit x multi-tty emacs)

Memory information:

((conses 16 74956 6410)

 (symbols 48 18012 0)

 (miscs 40 43 124)

 (strings 32 10961 5159)

 (string-bytes 1 296944)

 (vectors 16 9377)

 (vector-slots 8 386766 15535)

 (floats 8 70 63)

 (intervals 56 175 0)

 (buffers 976 11)

 (heap 1024 31954 1039))