bug#13475: 24.2.91; accept-process-output hangs emacs on killed sub-process

[Vitalie Spinu]

Hi, 

Accept-process-output, when run with WAIT argument, hangs emacs when the
underlying sub-process was killed. When WAIT is nil this problem does
not occur.

Start M-x shell and execute:

   (let ((proc (get-process "shell")))
     (process-send-string proc "sleep 60\n")
     (while (not (accept-process-output proc .01))))

This puts emacs in a loop as expected. Now kill the bash process from
outside emacs and you will see that emacs is still hanged.

This problem does not occur when WAIT argument is nil. For example on
the execution of the following code, emacs successfully exits the waiting
loop after the bash process has been killed:

   
   (let ((proc (get-process "shell")))
     (accept-process-output proc))
   

Thanks, 

    Vitalie



In GNU Emacs 24.2.91.1 (i686-pc-linux-gnu, GTK+ Version 2.24.13)
 of 2012-12-29 on vitoshka-home
Windowing system distributor `The X.Org Foundation', version 11.0.11300000
System Description:     Ubuntu 12.10

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:
  semantic-minor-modes-format: ((:eval (if (or semantic-highlight-edits-mode 
semantic-show-unmatched-syntax-mode)  S)))
  global-semanticdb-minor-mode: t
  global-semantic-idle-scheduler-mode: t
  semantic-mode: t
  jabber-activity-mode: t
  TeX-PDF-mode: t
  sr-popviewer-mode: t
  global-auto-complete-mode: t
  auto-complete-mode: t
  diff-auto-refine-mode: t
  helm-match-plugin-mode: t
  shell-dirtrack-mode: t
  eldoc-mode: t
  recentf-mode: t
  show-paren-mode: t
  savehist-mode: t
  display-time-mode: t
  ido-everywhere: t
  global-auto-revert-mode: t
  global-subword-mode: t
  subword-mode: t
  tooltip-mode: t
  mouse-wheel-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
  hs-minor-mode: t

Recent input:
s s SPC " h <backspace> s h e l l C-f ) ) ) C-n <tab> 
C-n <tab> M-f M-f M-f M-f M-b M-d p r o c M-f M-b M-d 
. 0 0 1 <backspace> <backspace> 1 C-f <return> C-p 
C-f C-f C-e C-M-b <C-backspace> <backspace> SPC C-e 
) C-c t <return> <return> M-: M-p C-k C-y M-y C-p C-o 
C-x b s c <return> C-x C-e C-p C-n <tab> ) C-x C-e 
C-n C-p C-p <return> ( p r o c e s s - s e n d - s 
t <tab> SPC " C-b p r o c SPC <down-mouse-1> <mouse-1> 
b s <backspace> <backspace> C-b s l e e p SPC 3 0 \ 
n C-e ) C-n C-e C-x C-e C-p C-n C-o C-o <return> <return> 
C-o M-b M-b M-b M-b M-b C-b ( n o t SPC M-f C-h f <return> 
<down-mouse-5> <mouse-5> <down-mouse-5> <mouse-5> <down-mouse-4> 
<mouse-4> <down-mouse-1> <mouse-1> C-o C-o C-o <return> 
<return> C-o C-e ) C-x C-e C-p M-b M-b C-d 6 C-n C-p 
<backspace> 3 C-n C-e C-x C-e C-p M-b M-b C-d 6 C-p 
C-a C-SPC C-n C-n C-n M-w <return> C-o C-o C-o C-c 
t <return> <return> C-o C-y C-p C-p C-p M-f M-f C-n 
C-a C-k C-k M-f M-f C-f <M-backspace> <backspace> C-M-f 
C-b <M-backspace> <backspace> <backspace> M-m C-f M-f 
C-f <M-backspace> <backspace> C-M-f C-e <backspace> 
<backspace> C-M-b <tab> n <backspace> C-n <tab> C-e 
C-x C-e C-p C-p C-n C-n C-o C-o C-o <return> C-o C-p 
C-p C-p C-e C-p M-b M-b C-d 3 C-n C-e C-x C-e C-o C-o 
C-o C-c t <return> C-o C-x C-e C-o C-o C-o <return> 
C-c t C-o C-n C-n C-n C-x C-e C-p C-n C-n C-x 4 C-g 
M-x e <backspace> <backspace> r e p o r t <return>

Recent messages:
nil
Quit
Mark set [2 times]
nil
user-error: Current buffer has no process
let: Buffer *scratch* has no process
Quit
user-error: Current buffer has no process
nil
with-no-warnings: Text is read-only

Load-path shadows:
/home/vitoshka/Dropbox/ELPA/magit-20130112.1253/.dir-locals hides 
/home/vitoshka/Dropbox/ELPA/sunrise-commander-20130107.37/.dir-locals
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~/VC/gnus/.dir-locals
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~/VC/org-mode/lisp/ob-plantuml hides 
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~/VC/org-mode/lisp/org-gnus hides /home/vitoshka/TVC/emacs/lisp/org/org-gnus
~/VC/org-mode/lisp/ob-maxima hides /home/vitoshka/TVC/emacs/lisp/org/ob-maxima
~/VC/org-mode/lisp/ob-js hides /home/vitoshka/TVC/emacs/lisp/org/ob-js
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~/VC/org-mode/lisp/org-mac-message hides 
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~/VC/org-mode/lisp/ob-awk hides /home/vitoshka/TVC/emacs/lisp/org/ob-awk
~/VC/org-mode/lisp/org-wl hides /home/vitoshka/TVC/emacs/lisp/org/org-wl
~/VC/org-mode/lisp/ob-picolisp hides 
/home/vitoshka/TVC/emacs/lisp/org/ob-picolisp
~/VC/org-mode/lisp/org-protocol hides 
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~/VC/org-mode/lisp/ob-sh hides /home/vitoshka/TVC/emacs/lisp/org/ob-sh
~/VC/org-mode/lisp/org-exp hides /home/vitoshka/TVC/emacs/lisp/org/org-exp
~/VC/org-mode/lisp/ob-dot hides /home/vitoshka/TVC/emacs/lisp/org/ob-dot
~/VC/org-mode/lisp/org-archive hides 
/home/vitoshka/TVC/emacs/lisp/org/org-archive
~/VC/gnus/lisp/sasl hides /home/vitoshka/TVC/emacs/lisp/net/sasl
~/VC/gnus/lisp/gnus-bookmark hides 
/home/vitoshka/TVC/emacs/lisp/gnus/gnus-bookmark
~/VC/gnus/lisp/sieve-mode hides /home/vitoshka/TVC/emacs/lisp/gnus/sieve-mode
~/VC/gnus/lisp/gnus-setup hides /home/vitoshka/TVC/emacs/lisp/gnus/gnus-setup
~/VC/gnus/lisp/gnus-kill hides /home/vitoshka/TVC/emacs/lisp/gnus/gnus-kill
~/VC/gnus/lisp/yenc hides /home/vitoshka/TVC/emacs/lisp/gnus/yenc
~/VC/gnus/lisp/messcompat hides /home/vitoshka/TVC/emacs/lisp/gnus/messcompat
~/VC/gnus/lisp/nnml hides /home/vitoshka/TVC/emacs/lisp/gnus/nnml
~/VC/gnus/lisp/deuglify hides /home/vitoshka/TVC/emacs/lisp/gnus/deuglify
~/VC/gnus/lisp/mm-extern hides /home/vitoshka/TVC/emacs/lisp/gnus/mm-extern
~/VC/gnus/lisp/gnus-html hides /home/vitoshka/TVC/emacs/lisp/gnus/gnus-html
~/VC/gnus/lisp/nnweb hides /home/vitoshka/TVC/emacs/lisp/gnus/nnweb
~/VC/gnus/lisp/gnus-srvr hides /home/vitoshka/TVC/emacs/lisp/gnus/gnus-srvr
~/VC/gnus/lisp/pgg-gpg hides /home/vitoshka/TVC/emacs/lisp/obsolete/pgg-gpg
/home/vitoshka/Dropbox/ELPA/rebox2-20121113.2100/rebox2 hides 
/home/vitoshka/Dropbox/.emacs.d/site-lisp/rebox2/rebox2

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