edebug can hang Emacs

[Alex Schroeder]

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In GNU Emacs 21.2.92.1 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2002-11-22 on confusibombus
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: C
  locale-coding-system: nil
  default-enable-multibyte-characters: t

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:



In emacs -q, edebug the following defun using C-u M-C-x:

(defun test ()
  (let ((l (make-list 100000 1)))
    (dolist (i l)
      (1+ i))))

Now call it:

(test)

When you get to the dolist, Emacs hangs.  I cannot awaken it using C-g
multiple times, ESC multiple times, C-z multiple times, having the
window manager send a kill, switching to the xterm running GDB and
hitting C-c or C-z multiple times also does not change anything --
neither Emacs nor GDB is killed or interrupted.

This should be handler more gracefully.  I don't even know what causes
the problem -- is Emacs trying to print the list l in a message, and
trying to determine which parts not to show?  If so, perhaps Emacs
needs a way to estimate the size of something, before starting to
print it.

Alex.



Recent input:
<escape> <escape> <escape> C-c n <down> <down> <down> 
<down> <down> <return> <down> <down> <down> d d d d 
<down> <down> <down> <return> ! s <up> <up> <up> d 
<down> <return> SPC ! s q <return> <return> s q <down> 
<down> <down> <down> <return> d <return> ! s <return> 
! ! s q <return> <return> SPC SPC s c y <escape> x 
r e p o r t - e m <tab> <return>

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