bug#15826: 24.3.50; SMIE hangs in sh-mode

[Aaron Ecay <aaronecay@gmail.com>]

I observe hangs when using sh-mode in recent trunk emacs (latest commit
Tue Nov 5 18:36:37 2013 +0200).  Recipe to reproduce:

- emacs -Q
- C-x C-f foo.sh
- type “for i in”
- immediately after entering the ‘n’, emacs will hang

Setting debug-on-quit to t and quitting yields the following backtrace:
Debugger entered--Lisp error: (quit)
  re-search-backward("\\(?:\\(?:^\\|[^\\]\\)\\(?:\\\\\\\\\\)*\\(\\(?:&&\\|;\\(?:;&\\|[&;]\\)\\||[&|]\\|[&;|]\\)\\)\\)\\=" 1 t)
  looking-back("\\(?:^\\|[^\\]\\)\\(?:\\\\\\\\\\)*\\(\\(?:&&\\|;\\(?:;&\\|[&;]\\)\\||[&|]\\|[&;|]\\)\\)" 1 greedy)
  sh-smie-sh-backward-token()
  sh-smie--sh-keyword-in-p()
  sh-smie--sh-keyword-p("in")
  sh-smie-sh-backward-token()
  smie-blink-matching-open()
  self-insert-command(1)
  call-interactively(self-insert-command nil nil)
  command-execute(self-insert-command)

Thanks,
Aaron



In GNU Emacs 24.3.50.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.10.2)
 of 2013-11-05 on haize
Windowing system distributor `The X.Org Foundation', version 11.0.11404000
Configured using:
 `configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var
 --libexecdir=/usr/lib --mandir=/usr/share/man --without-sound
 --with-xft --with-x-toolkit=gtk --with-gif=no 'CFLAGS=-march=x86-64
 -mtune=generic -O2 -pipe -fstack-protector --param=ssp-buffer-size=4'
 CPPFLAGS=-D_FORTIFY_SOURCE=2
 LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro'

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

-- 
Aaron Ecay