bug#6585: 23.1; Hang / CPU 100% on background interaction when in minibuffer

[Jason S. Cornez]

On 08/31/2010 03:09 PM, Stefan Monnier wrote:
> 100% agreement.  Patch welcome,
> 
> 
>         Stefan

How about something like this...
----8<----
src/keyboard.c /usr/local/emacs-23.2/src/keyboard.c
*** src/keyboard.c      2010-04-04 00:26:07.000000000 +0200
--- /usr/local/emacs-23.2/src/keyboard.c        2010-08-31
17:03:14.648740153 +0200
*************** interrupt_signal (signalnum)    /* If we do
*** 11122,11127 ****
--- 11122,11136 ----
    errno = old_errno;
  }

+
+ /* JSC: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=6585 */
+
+ /* If emacs is stuck because `inhibit-quit' is true, then keep track
+    of the number of times C-g has been requested.  If C-g is pressed 3
+    times, then quit anyway.  If `debug-on-quit' is true, then it is
+    honored when the quit occurs after the third C-g. */
+ static int force_quit_count;
+
  /* This routine is called at interrupt level in response to C-g.

     It is called from the SIGINT handler or kbd_buffer_store_event.
*************** handle_interrupt ()
*** 11239,11246 ****
          UNGCPRO;
        }
        else
!       /* Else request quit when it's safe */
!       Vquit_flag = Qt;
      }

  /* TODO: The longjmp in this call throws the NS event loop integration
off,
--- 11248,11266 ----
          UNGCPRO;
        }
        else
!         {
!           /* Else request quit when it's safe */
!           if (NILP (Vquit_flag))
!             {
!               force_quit_count = 0;
!             }
!         if (++force_quit_count == 3)
!             {
!               immediate_quit = 1;
!               Vinhibit_quit = Qnil;
!             }
!           Vquit_flag = Qt;
!         }
      }

  /* TODO: The longjmp in this call throws the NS event loop integration
off,
----8<----

This does indeed solve the problem for me.  But I freely admit that I've
never done emacs development before and so something more may be
required or desired.  Anyway, this is certain a start and I hope it helps.

Best,
-Jason