bug#17776: 24.3; bug? regression: xterm-mouse-mode does not work any more with rxvt-unicode

[Gregor Zattler <grfz@gmx.de>]

xterm-mouse-mode used to work under rxvt-unicode but does not any more.
I'm not sure who ist to blame (emacs or rxvt-unicode).

How to reproduce:

start emacs like so:

urxvt -e emacs-snapshot -Q -nw --eval '(progn (xterm-mouse-mode 1)(switch-to-buffer "*Messages*")(toggle-debug-on-error))'

then klick in the one window.  You'll see a backtrace etc.

I see:
- in *Messages*

Entering debugger...
[ is undefined
M is undefined
# is undefined
@ is undefined


- backtrace:
Debugger entered--Lisp error: (wrong-type-argument stringp nil)
  intern(nil)
  xterm-mouse--read-event-sequence-1000()
  xterm-mouse-event(nil)
  xterm-mouse-translate-1()
  xterm-mouse-translate(nil)


This happens with
rxvt-unicode (urxvt) v9.20 - released: 2014-04-26
options:
perl,xft,styles,combining,blink,iso14755,unicode3,encodings=eu+vn+jp+jp-ext+kr+zh+zh-ext,fade,transparent,tint,pixbuf,XIM,frills,selectionscrolling,wheel,slipwheel,smart-resize,cursorBlink,pointerBlank,scrollbars=plain+rxvt+NeXT+xterm


I git-bisected this:

da26b804bfee2a137e999bb03c736bf85dd3bf5a is the first bad commit
commit da26b804bfee2a137e999bb03c736bf85dd3bf5a
Author: Stefan Monnier <monnier@iro.umontreal.ca>
Date:   Wed May 7 21:46:15 2014 -0400

    * lisp/xt-mouse.el: Drop spurious/oddly shaped events.
    (xterm-mouse--read-event-sequence-1000): Return nil if something looks fishy.
    (xterm-mouse-event): Propagate it.
    (xterm-mouse-translate-1): Handle it.

:040000 040000 bfe3c645c9b390c2bca2aa5b114ec10594142782 42a69b7988a9f3bc90a86a26401b5036ac41f876 M      lisp


HTH, thanks for your attention, Gregor



In GNU Emacs 24.3.1 (i486-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2014-05-16 on babin, modified by Debian
System Description:	Debian GNU/Linux testing (jessie)

Configured using:
 `configure '--build' 'i486-linux-gnu' '--build' 'i486-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/i386-linux-gnu' '--with-x=yes'
 '--with-x-toolkit=lucid' '--with-toolkit-scroll-bars' '--without-gconf'
 '--without-gsettings' 'build_alias=i486-linux-gnu' 'CFLAGS=-g -O2
 -fstack-protector --param=ssp-buffer-size=4 -Wformat
 -Werror=format-security -Wall' 'LDFLAGS=-Wl,-z,relro'
 'CPPFLAGS=-D_FORTIFY_SOURCE=2''

Important settings:
  value of $LC_COLLATE: de_DE.utf8
  value of $LC_CTYPE: de_DE.utf8
  value of $LC_MESSAGES: POSIX
  value of $LC_MONETARY: de_DE.utf8
  value of $LC_NUMERIC: de_DE.utf8
  value of $LC_TIME: de_DE.utf8
  value of $LANG: de_DE.utf8
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Lisp Interaction

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
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
ESC x r e p o r t - e m a TAB RET

Recent messages:
("emacs24")
Loading term/xterm...done
For information about GNU Emacs and the GNU system, type C-h C-a.

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message format-spec 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 mail-prsvr mail-utils 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 font-render-setting
x-toolkit x multi-tty emacs)