bug#12183: 24.1.50; Unrecognized pasteboard formats quit yank in Emacs.app

[Jason T. Miller]

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':


1. Start Emacs.app in OS X (or, presumably, GNUstep). On OS X,
    $PATH_TO_EMACS_APP/Contents/MacOS/Emacs -Q
is fine.

2. Load something in the pasteboard that lacks a plain text representation*.

3. Yank. Emacs aborts the yank with the quit message "empty or unsupported
pasteboard type".

From my perspective at least, this behavior is never useful, frequently 
annoying,
and particularly painful when `save-interprogram-paste-before-kill' is enabled.
My preferred solution is for Emacs to simply ignore unsupported pasteboard data.
For example, replacing

    (defun ns-get-pasteboard ()
      "Returns the value of the pasteboard."
      (ns-get-selection-internal 'CLIPBOARD))

with

    (defun ns-get-pasteboard ()
      "Returns the value of the pasteboard, or nil for unsupported formats."
     (condition-case nil
         (ns-get-selection-internal 'CLIPBOARD)
       (quit nil)))

has this effect, while retaining the old behavior in the Objective-C
implementation for applications that require special handling for empty,
unrecognized, and invalid pasteboard data.

* Convenient OS X example: without leaving Emacs, take a screenshot with
C-Command-# (or whatever keyboard shortcut is defined in
    System Preferences -> Keyboard -> Keyboard Shortcuts -> Screen Shots
for "Copy picture of screen to the...").


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
/Applications/Emacs.app/Contents/Resources/etc/DEBUG.


In GNU Emacs 24.1.50.1 (x86_64-apple-darwin12.0.0, NS apple-appkit-1187.00)
 of 2012-08-09 on socrates.jasomill.at.home
Windowing system distributor `Apple', version 10.3.1187
Configured using:
 `configure '--with-ns''

Important settings:
  value of $LANG: en_US.UTF-8
  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
  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:
M-x r e p o r <tab> <return>

Recent messages:
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 ns-win 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 files text-properties overlay sha1 md5 base64 format env
code-pages mule custom widget hashtable-print-readable backquote
make-network-process ns multi-tty emacs)

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